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Sample records for femtosecond laser-assisted keratoplasty

  1. Preliminary results of femtosecond laser-assisted descemet stripping endothelial keratoplasty.

    NARCIS (Netherlands)

    Cheng, Y.Y.; Hendrikse, F.; Pels, E.; Wijdh, R.J.; Cleynenbreugel, H. van; Eggink, C.A.; Rij, G. van; Rijneveld, W.J.; Nuijts, R.M.

    2008-01-01

    OBJECTIVE: To evaluate the preliminary visual results of femtosecond laser-assisted Descemet stripping endothelial keratoplasty (FS-DSEK). METHODS: We prospectively analyzed results of 20 consecutive patients with Fuchs endothelial dystrophy or aphakic/pseudophakic bullous keratopathy who underwent

  2. Preliminary results of femtosecond laser-assisted descemet stripping endothelial keratoplasty

    NARCIS (Netherlands)

    Cheng, Yanny Y. Y.; Hendrikse, Fred; Pels, Elisabeth; Wijdh, Robert-Jan; van Cleynenbreugel, Hugo; Eggink, Cathariena A.; van Rij, Gabriel; Rijneveld, Wilhelmina J.; Nuijts, Rudy M. M. A.

    2008-01-01

    Objective: To evaluate the preliminary visual results of femtosecond laser-assisted descemet stripping endothelial keratoplasty (FS-DSEK). keratoplasty (FS-DSEK). Methods: We prospectively analyzed results of 20 consecutive patients with Fuchs endothelial dystrophy or aphakic/pseudophakic bullous ke

  3. Femtosecond laser-assisted deep anterior lamellar keratoplasty for keratoconus and keratectasia

    Institute of Scientific and Technical Information of China (English)

    Yan; Lu; Yu-Hua; Shi; Li-Ping; Yang; Yi-Rui; Ge; Xiang-Fei; Chen; Yan; Wu; Zhen-Ping; Huang

    2014-01-01

    ·AIM: To describe the initial outcomes and safety of femtosecond laser-assisted deep anterior lamellar keratoplasty(DALK) for keratoconus and post-LASIK keratectasia.·METHODS: In this non-comparative case series, 10 eyes of 9 patients underwent DALK procedures with a femtosecond laser(Carl Zeiss Meditec AG, Jena,Germany). Of the 9 patients, 7 had keratoconus and 2had post-LASIK keratectasia. A 500 kHz VisuMax femtosecond laser was used to perform corneal cuts on both donor and recipient corneas. The outcome measures were the uncorrected visual acuity(UCVA),best-corrected visual acuity(BCVA), corneal thickness,astigmatism, endothelial density count(EDC), and corneal power.·RESULTS: All eyes were successfully treated. Early postoperative evaluation showed a clear graft in all cases. Intraoperative complications included one case of a small Descemet’s membrane perforation.Postoperatively, there was one case of stromal rejection,one of loosened sutures, and one of wound dehiscence.A normal corneal pattern topography and transparency were restored, UCVA and BCVA improved significantly,and astigmatism improved slightly. There was no statistically significant decrease in EDC.· CONCLUSION: Our early results indicate that femtosecond laser-assisted deep anterior lamellar keratoplasty could improve UCVA and BCVA in patients with anterior corneal pathology. This approach shows promise as a safe and effective surgical choice in the treatment of keratoconus and post-LASIK keratectasia.

  4. Femtosecond laser assisted design of sutureless intrastromal graft as an alternative to partial thickness keratoplasty

    Science.gov (United States)

    Rossi, Francesca; Durkee, Heather; Pini, Roberto; Canovetti, Annalisa; Malandrini, Alex; Lenzetti, Ivo; Rubino, Pierangela; Leaci, Rosachiara; Neri, Alberto; Scaroni, Patrizia; Menabuoni, Luca; Macaluso, Claudio

    2014-02-01

    Minimally invasive laser assisted surgery in ophthalmology is continuously developing in order to find new surgical approaches, preserve patient tissue and improve surgical results in terms of cut precision, restoration of visual acuity, and invasiveness. In order to achieve these goals, the current approach in corneal transplant is lamellar keratoplasty, where only the anterior or posterior part of the patient's cornea is substituted depending on the lesion or pathology. In this work, we present a novel alternative approach: a case study of intrastromal sutureless transplant, where a portion of the anterior stroma of a donor cornea was inserted into the stroma of the recipient cornea, aiming to restore the correct thickness of the patient's cornea. The patient cornea was paracentrally thin, as the result of a trophic ulcer due to ocular pemphigoid. A discoid corneal graft from the anterior stroma of a donor eye was prepared: a femtosecond laser cut with a trapezoidal profile (thickness was 300 μm, minor and major basis were 3.00 and 3.50 mm, respectively). In the recipient eye, an intrastromal cut was also performed with the femtosecond laser using a specifically designed mask; the cut position was 275 μm in depth. The graft was loaded into an injector and inserted as an intrastromal presbyopic implant. The postoperative analysis evidenced a clear and stable graft that selectively restored corneal thickness in the thinned area. Intrastromal corneal transplant surgery is a minimally invasive alternative to anterior or posterior lamellar keratoplasty in select cases. We believe that Sutureless Intrastromal Laser Keratoplasty (SILK) could open up new avenues in the field of corneal transplantation by fully utilizing the potential and precision of existing lasers.

  5. Observation on ultrastructure and histopathology of cornea following femtosecond laser-assisted deep lamellar keratoplasty for acute corneal alkaline burns.

    Science.gov (United States)

    Li, Wen-Jing; Hu, Yu-Kun; Song, Hui; Gao, Xiao-Wei; Zhao, Xu-Dong; Dong, Jing; Guo, Yun-Lin; Cai, Yan

    2016-01-01

    To demonstrate the changes in ultrastructure and histopathology of the cornea in acute corneal alkaline burns after femtosecond laser-assisted deep lamellar keratoplasty. The New Zealand white rabbits treated with alkaline corneal burn were randomized into two groups, Group A (16 eyes) with femtosecond laser-assisted deep lamellar keratoplasty 24h after burn and Group B (16 eyes) without keratoplasty as controls. All eyes were evaluated with transmission electron microscopy (TEM) at 1, 2, 3, and 4wk follow-up, then all corneas were tested by hematoxylin and eosin staining histology. The corneal grafts in Group A were transparent, while those in Group B showed corneal stromal edema and loosely arranged collagen fibers. One week after treatment, TEM revealed the intercellular desmosomes in the epithelial layers and intact non-dissolving nuclei in Group A. At week 4, the center of the corneas in Group A was transparent with regularly arranged collagen fibers and fibroblasts in the stroma. In Group B, squamous cells were observed on the corneal surface and some epithelial cells were detached. Femtosecond laser-assisted deep lamellar keratoplasty can suppress inflammatory responses, prevent toxic substance-induced injury to the corneal endothelium and inner tissues with quicker recovery and better visual outcomes.

  6. Femtosecond laser-assisted keratoplasty combined with cataract extraction in a patient with keratoconus and oculocutaneous albinism

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    Dorottya Pásztor

    2016-01-01

    Full Text Available In this study, we present a case of a 58-year-old male patient with oculocutaneous albinism, keratoconus, total cataract, and glaucoma originating from father-daughter incest. He underwent femtosecond laser-assisted keratoplasty with “open-sky” cataract extraction and posterior chamber intraocular lens implantation. One week after surgery his uncorrected visual acuity improved from hand motion to 20/200. Six months later corneal K values were 49.1 D in the flat and 50.0 D in the steep meridian. The graft had a central corneal thickness of 488 µm and was well fitted. The patient's quality of life improved substantially due to the surgery. To the best of our knowledge, this is the first report on the association of albinism with advanced keratoconus, total cataract, and glaucoma. Moreover, no previous report on femtosecond laser-assisted keratoplasty using VisuMax femtosecond laser system with “open-sky” cataract extraction is available in the literature. The VisuMax femtosecond laser-assisted keratoplasty ensures fast patient rehabilitation in such challenging cases.

  7. Femtosecond laser-assisted keratoplasty combined with cataract extraction in a patient with keratoconus and oculocutaneous albinism

    Science.gov (United States)

    Pásztor, Dorottya; Kolozsvári, Bence Lajos; Losonczy, Gergely; Fodor, Mariann

    2016-01-01

    In this study, we present a case of a 58-year-old male patient with oculocutaneous albinism, keratoconus, total cataract, and glaucoma originating from father-daughter incest. He underwent femtosecond laser-assisted keratoplasty with “open-sky” cataract extraction and posterior chamber intraocular lens implantation. One week after surgery his uncorrected visual acuity improved from hand motion to 20/200. Six months later corneal K values were 49.1 D in the flat and 50.0 D in the steep meridian. The graft had a central corneal thickness of 488 µm and was well fitted. The patient's quality of life improved substantially due to the surgery. To the best of our knowledge, this is the first report on the association of albinism with advanced keratoconus, total cataract, and glaucoma. Moreover, no previous report on femtosecond laser-assisted keratoplasty using VisuMax femtosecond laser system with “open-sky” cataract extraction is available in the literature. The VisuMax femtosecond laser-assisted keratoplasty ensures fast patient rehabilitation in such challenging cases. PMID:27146942

  8. Femtosecond laser-assisted keratoplasty in a child with corneal opacity:case report

    Directory of Open Access Journals (Sweden)

    E. Yu. Markova

    2014-01-01

    Full Text Available Corneal opacities are the fourth cause of blindness world-wide. Over the past two centuries, various corneal transplantation (i.e., keratoplasty methods have been developed and improved. Nowadays, femtolaserssisted keratoplasty is one of most promising techniques. Femtosecond laser have several advantages that provide additional surgical benefits. Among them, no thermal injury, the ability to cut deeply on a single plane and to perform various corneal profiles should be mentioned. In children, corneal disorders are of special importance while femtosecondassisted keraatoplasty case reports are rare. Here, we describe femtosecond laserssisted penetrating keratoplasty in a girl with a rough central corneal opacity.

  9. Femtosecond laser-assisted lamellar keratoplasty Transplante lamelar auxiliado pelo laser de fentosegundo

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    Hunson Kaz Soong

    2008-08-01

    Full Text Available Lamellar keratoplasty consists of transplanting partial-thickness donor cornea onto a complementary recipient bed. Manual lamellar dissection is technically very difficult, time-consuming, and imprecise. Also, the manually-dissected lamellar interface often has topographical irregularities that may optically degrade the best-corrected visual acuity. The femtosecond clinical laser (IntraLase FS LaserTM, Irvine, CA is a recent innovation that can be programmed to produce bladeless, precise lamellar cuts at any depth with accompanying trephination cuts for both anterior and posterior lamellar transplantion. Posterior laser cuts may be used to assist in deep lamellar endothelial keratoplasty or Descemet's stripping automated endothelial keratoplasty.A ceratoplastia lamelar consiste em transplante de espessura parcial da córnea doadora em um leito receptor complementar. A dissecção lamelar manual é técnica de difícil realização, imprecisa e que demanda tempo. Além disso, a interface lamelar freqüentemente apresenta irregularidade topográfica que pode comprometer a acuidade visual final. O laser clínico "femtosecond" (IntraLase FS LaserTM, Irvine, CA é uma recente inovação que pode ser utilizado para produzir cortes lamelares precisos em qualquer profundidade da córnea, acompanhados de cortes verticais tanto para transplantes lamelares anteriores como posteriores sem a utilização de lâminas. Os cortes posteriores podem ser utilizados para a realização de ceratoplastia endotelial lamelar profunda ou ceratoplastia endotelial com remoção da membrana de Descemet.

  10. Results of Femtosecond Laser-Assisted Descemet Stripping Automated Endothelial Keratoplasty

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    Mohamed H. Hosny

    2017-01-01

    Full Text Available Purpose. To evaluate femtosecond laser in DSAEK surgery as an improvement to manual DSAEK. Settings. Department of Ophthalmology, Cairo University. Design. A retrospective observational clinical study. Methods. 20 eyes with SBK and Fuchs’ dystrophy underwent a Femto-assisted DSAEK by laser cutting of two matching posterior stromal discs in the recipient and donor corneas and then fitting the donor disc in the posterior corneal defect of the recipient using Busin’s glide or Terry forceps. Results. Corneal thickness decreased significantly from a mean of 900-micron preoperative values (900.7 m to 562 m postoperatively. Evidence of side healing was documented by OCT. One patient had a double AC, one patient had an air interface entrapment “Double Bubble,” one patient had a fungal infection and was treated by a therapeutic penetrating keratoplasty, and one patient had a CMO. Conclusion. Femtolaser-assisted DSAEK may be superior to manual techniques as it offers better centration, thinner graft/host complex, earlier corneal detergecense, and stronger healing. This study was registered at Researchregistry.com with a UID: researchregistry2274.

  11. Femtosecond laser-assisted penetrating keratoplasty in the treatment for keratoconus%飞秒激光辅助角膜移植手术在圆锥角膜治疗中的应用

    Institute of Scientific and Technical Information of China (English)

    朱小敏; 叶芬; 吴艳; 陆燕; 黄振平

    2016-01-01

    Femtosecond laser as a type of infrared laser operated in pulse fashion has been applied in the treatment of keratoconus .Compared with traditional methods such as keratoplasty , femtosecond laser-assisted penetrating keratoplasty and femtosecond laser-assisted deep anterior lamellar keratoplasty have better clinical outcomes and higher safety to pa -tients.This paper focuses on the related applications of femtosecond laser -assisted keratoplasty in the treatment for kerato-conus, and our experience in using this new technique .%飞秒激光是一种以脉冲形式运转的红外线激光,在圆锥角膜的手术治疗中得到了很好的应用,与传统手术方式相比,飞秒激光辅助的穿透性角膜移植术和飞秒激光辅助的深板层角膜移植术在圆锥角膜患者术后均取得了良好的临床效果和更高的安全性。本文就近几年飞秒激光在圆锥角膜手术治疗中的应用进展进行综述,并结合我们临床应用中的经验和体会进行阐述。

  12. [Comparison of anatomic and functional results between Z6 femtosecond laser assisted and manual trephination in deep anterior lamellar keratoplasty for advanced keratoconus [French version

    Science.gov (United States)

    Blériot, A; Martin, E; Lebranchu, P; Zimmerman, K; Libeau, L; Weber, M; Vabres, B; Orignac, I

    2017-09-01

    The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4 of the Krumeich classification. It is a retrospective study including all patients with stage 4 keratoconus who underwent femtosecond laser assisted DALK between November 2012 and November 2015 in Nantes hospital. We compared those patients to a group of patients who underwent manual DALK in the same period, paired by age and maximal keratometry. We assessed visual acuity, pachymetry, endothelial cell density (specular microscopy), and keratometry before surgery and at 4, 8 and 12 months of follow-up. Laser settings and intraoperative complications were recorded. Nineteen patients underwent surgery by femtosecond assisted DALK, 6 women and 12 men with average age 30.2±10.8 years at transplantation. They were paired with a group of 17 patients who underwent manual DALK in order to compare results. Before surgery, mean visual acuity in the femtosecond group was 0.90 logMAR versus 0.89 logMAR in the manual group, showing no statistically significant difference (P=0.96). Both groups were similar in terms of preoperative age, mean keratometry, pachymetry and endothelial cell density. Average visual acuity post-surgery was 0.27, 0.26; and 0.14 logMAR for femtosecond DALK versus 0.27, 0.17 et 0.25 for manual DALK at 4, 8 and 12 months follow-up, respectively showing no statistically significant difference. After surgery, at 4, 8 and 12 months, mean pachymetry

  13. Comparison of 12-month anatomic and functional results between Z6 femtosecond laser-assisted and manual trephination in deep anterior lamellar keratoplasty for advanced keratoconus.

    Science.gov (United States)

    Blériot, A; Martin, E; Lebranchu, P; Zimmerman, K; Libeau, L; Weber, M; Vabres, B; Orignac, I

    2017-06-01

    The management of severe keratoconus requires corneal transplantation, for which the gold standard is deep anterior lamellar keratoplasty (DALK), preserving the healthy Descemet's membrane and endothelium. The safety and reproducibility of corneal cuts have been improved by the evolution of femtosecond lasers in refractive surgery, and femtosecond laser in DALK would seem to provide the same advantages over the manual method. In our retrospective study, we compare functional and anatomical results of femtosecond-assisted DALK versus manual trephination DALK in patients with keratoconus in stage 4 of the Krumeich classification. It is a retrospective study including all patients with stage 4 keratoconus who underwent femtosecond laser-assisted DALK between November 2012 and November 2015 in Nantes university medical center. We compared those patients to a group of patients who underwent manual DALK in the same period, paired by age and maximal keratometry. We assessed visual acuity, pachymetry, endothelial cell density (specular microscopy), and keratometry before surgery and at 4, 8 and 12 months of follow-up. Laser settings and intraoperative complications were recorded. Nineteen patients underwent surgery by femtosecond-assisted DALK, 6 women and 12 men with average age 30.2±10.8 years at transplantation. They were paired with a group of 17 patients who underwent manual DALK in order to compare results. Before surgery, mean visual acuity in the femtosecond group was 0.90 logMAR versus 0.89 logMAR in the manual group, showing no statistically significant difference (P=0.96). Both groups were similar in terms of preoperative age, mean keratometry, pachymetry and endothelial cell density. Average visual acuity post-surgery was 0.27; 0.26; and 0.14 logMAR for femtosecond DALK versus 0.27; 0.17 et 0.25 for manual DALK at 4, 8 and 12 months follow-up respectively, showing no statistically significant difference. After surgery, at 4, 8 and 12 months, mean

  14. 飞秒激光辅助的深板层角膜移植治疗圆锥角膜患者的护理%Nursing of femtosecond laser-assisted deep anterior lamellar keratoplasty for keratoconus

    Institute of Scientific and Technical Information of China (English)

    卢玉文; 丁颖; 刘佳; 叶婷; 张利

    2014-01-01

    目的:探讨飞秒激光辅助的深板层角膜移植治疗圆锥角膜患者的护理方法。方法对9例10眼圆锥角膜患者行飞秒激光辅助的深板层角膜移植术,进行充分的术前、术中、术后护理,总结护理经验。结果所有患者术后效果满意,视力均有不同程度提高,达到治疗目的。1例患者术中出现角膜后弹力层微穿孔并发症。结论飞秒激光辅助的深板层角膜移植术对圆锥角膜患者安全有效。术前协助患者做好飞秒激光参数设置相关的眼部检查,术中协助患者配合手术及严格无菌操作,术后严密观察病情变化,出院指导及随访是巩固治疗成果的重要环节。%Objective To explore the nursing of patients with keratoconus after performing the deep anterior lamellar keratoplasty assisted by femtosecond laser .Methods 9 patients with keratoconus hadfemtosecond laser-assisted deep anterior lamellar keratoplasty . Adequate preoperative , intraoperative and postoperative nursing care was performed .Results All the patients were satisfied with the results of sugery and their visual acuity were improved for various status .The purpose of treatment was achieved .One patient had intraoperative complication of small descemet membrane perforation .Conclusions Our early results of femtosecond laser-assisted deep anterior lamellar keratoplasty turn to be safe and effective .The key nursing care of preoperative period is to help patients make ophthalmic examination related to parameter settings of femtosecond laser , and the intraoperative period is to help patients coordinate with surgery and closely observe the changes of patients .The instructions of discharge and follow-up are also the important parts of consolidation the therapy outcomes .

  15. Femtosecond laser-assisted deep anterior lamellar keratoplasty using the big bubble technique for keratoconus%飞秒激光辅助的大气泡法深板层角膜移植治疗圆锥角膜

    Institute of Scientific and Technical Information of China (English)

    陆燕; 陈祥菲; 杨丽萍; 曹茜; 王春红; 黄振平

    2015-01-01

    Objective To evaluate the clinical results and safety of big bubble deep anterior lamellar keratoplasty assisted by a femtosecond laser for keratoconus.Methods A case series of 11 eyes of 9 keratoconus patients were enrolled in the study.A 500 kHz VisuMax femtosecond laser (Carl Zeiss Meditec AG,Jena,Germany) was used to create a vertical side cut on both donor and recipient corneas.The mean thinnest corneal thickness measured with ultrasound corneal pachymetry,was 359.7±49.8 μm.Preoperative UCVA was counting fingers (CF) to-0.1 and preoperative BCVA was CF to-0.12.The mean donor diameter was 7.51±0.14 mm and mean recipient diameter was 7.38±0.10 mm.Mean follow-up was 7.70±2.88 months.Results All eyes were successfully treated without intraoperative complications.Early postoperative evaluation showed a clear graft in all cases.Mean corneal thickness was 481.4±51.3 μm.A normal corneal topographic pattern was restored.At the last postoperative examination,UCVA was 0.15 to 0.40 and the BCVA was 0.30 to 0.80.Conclusion Our early results indicate that femtosecond laser-assisted deep anterior lamellar keratoplasty using the big bubble technique shows promise as a safe and effective surgical choice in the treatment of keratoconus.%目的 评价飞秒激光辅助的大气泡法深板层角膜移植术治疗圆锥角膜临床效果及安全性.方法 系列病例研究.9例(11眼)圆锥角膜患者采用飞秒激光辅助进行大气泡法深板层角膜移植手术.供体及受体角膜均采用500 kHz VisuMax飞秒激光进行垂直边切,术前超声测量角膜最薄点厚度,角膜厚度为(359.7±49.8) μm,术前UCVA为指数~0.1,术前BCVA为指数~0.12,供体直径为(7.51±0.14)mm,受体直径为(7.38±0.10)mm,随访时间为(7.70±2.88)个月.结果 所有患者手术顺利,术中无并发症,术后早期所有角膜植片透明.角膜厚度为(481.4±51.3)μm,角膜地形图恢复正常形态.术后最后1次随访,UCVA为0.15~0.40,BCVA为0.30~0

  16. Femtosecond-laser assisted cell reprogramming

    Science.gov (United States)

    Breunig, Hans Georg; Uchugonova, Aisada; Batista, Ana; König, Karsten

    2017-02-01

    Femtosecond-laser pulses can assist to transfect cells by creating transient holes in the cell membrane, thus making them temporarily permeable for extraneous genetic material. This procedure offers the advantage of being completely "virus free" since no viruses are used for the delivery and integration of gene factors into the host genome and, thereby, avoiding serious side effects which so far prevent clinical application. Unfortunately, focusing of the laser radiation onto individual cell membranes is quite elaborate and time consuming. Regarding these obstacles, we briefly review two optical setups for fast, efficient and high throughput laser-assisted cell transfection based on femtosecond laser pulse excitation. The first setup aims at assisting the transfection of adherent cells. It comprises of a modified laser-scanning microscope with beamshaping optics as well as home-made software to automate the detection, targeting and laser-irradiation process. The second setup aims at laser-assisted transfection of non-adherent cells in suspension which move in a continuous flow through the laser focus region. The setup allows to address a large number of cells, however, with much lower transfection efficiency than the individual-cell targeting approach.

  17. Femtosecond laser-assisted cataract surgery: A current review

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    Majid Moshirfar

    2011-01-01

    Full Text Available To evaluate the safety, efficacy, advantages, and limitations of femtosecond laser-assisted cataract surgery through a review of the literature. A PubMed search was conducted using topic-appropriate keywords to screen and select articles. Initial research has shown appropriate safety and efficacy of femtosecond laser-assisted cataract surgery, with improvements in anterior capsulotomy, phacofragmentation, and corneal incision. Limitations of these studies include small sample size and short-term follow-up. Cost-benefit analysis has not yet been addressed. Preliminary data for femtosecond laser-assisted cataract surgery shows appropriate safety and efficacy, and possible advantage over conventional cataract surgery. Questions to eventually be answered include comparisons of long-term postoperative complication rates-including infection and visual outcomes-and analysis of contraindications and financial feasibility.

  18. Deep Laser-Assisted Lamellar Anterior Keratoplasty with Microkeratome-Cut Grafts

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    Yokogawa, Hideaki; Tang, Maolong; Li, Yan; Liu, Liang; Chamberlain, Winston; Huang, David

    2016-01-01

    Background The goals of this laboratory study were to evaluate the interface quality in laser-assisted lamellar anterior keratoplasty (LALAK) with microkeratome-cut grafts, and to achieve good graft–host apposition. Methods Simulated LALAK surgeries were performed on six pairs of eye bank corneoscleral discs. Anterior lamellar grafts were precut with microkeratomes. Deep femtosecond (FS) laser cuts were performed on host corneas followed by excimer laser smoothing. Different parameters of FS laser cuts and excimer laser smoothing were tested. OCT was used to measure corneal pachymetry and evaluate graft-host apposition. The interface quality was quantified in a masked fashion using a 5-point scale based on scanning electron microscopy images. Results Deep FS laser cuts at 226–380 μm resulted in visible ridges on the host bed. Excimer laser smoothing with central ablation depth of 29 μm and saline as a smoothing agent did not adequately reduce ridges (score = 4.0). Deeper excimer laser ablation of 58 μm and Optisol-GS as a smoothing agent smoothed ridges to an acceptable level (score = 2.1). Same sizing of the graft and host cut diameters with an approximately 50 μm deeper host side-cut relative to the central graft thickness provided the best graft–host fit. Conclusions Deep excimer laser ablation with a viscous smoothing agent was needed to remove ridges after deep FS lamellar cuts. The host side cut should be deep enough to accommodate thicker graft peripheral thickness compared to the center. This LALAK design provides smooth lamellar interfaces, moderately thick grafts, and good graft-host fits. PMID:26890667

  19. Femtosecond laser enabled keratoplasty for advanced keratoconus

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    Yathish Shivanna

    2013-01-01

    Full Text Available Purpose : To assess the efficacy and advantages of femtosecond laser enabled keratoplasty (FLEK over conventional penetrating keratoplasty (PKP in advanced keratoconus. Materials and Methods: Detailed review of literature of published randomized controlled trials of operative techniques in PKP and FLEK. Results: Fifteen studies were identified, analyzed, and compared with our outcome. FLEK was found to have better outcome in view of better and earlier stabilization uncorrected visual acuity (UCVA, best corrected visual acuity (BCVA, and better refractive outcomes with low astigmatism as compared with conventional PKP. Wound healing also was noticed to be earlier, enabling early suture removal in FLEK. Conclusions: Studies relating to FLEK have shown better results than conventional PKP, however further studies are needed to assess the safety and intraoperative complications of the procedure.

  20. Eye-Tracker-Guided Non-Mechanical Excimer Laser Assisted Penetrating Keratoplasty

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    Achim Langenbucher

    2013-03-01

    Full Text Available Purpose: The purpose of the study was to implement a new eye tracking mask which could be used to guide the laser beam in automated non-mechanical excimer laser assisted penetrating keratoplasty. Materials and methods: A new trephination mask design with an elevated surface geometry has been proposed with a step formation between conical and flat interfaces. Two recipient masks of 7.5/8.0 mm have been manufactured and tested. The masks have outer diameter of 12.5 mm, step formation at 10.5 mm, and slope of conical surfaces 15°. Its functionality has been tested in different lateral positions and tilts on a planar surface, and pig eye experiments. After successful validation on porcine eyes, new masks have been produced and tested on two patients. Results: The build-in eye tracking software of the MEL 70 was always able to capture the masks. It has been shown that the unwanted pigmentation/pattern induced by the laser pulses on the mask surface does not influence the eye-tracking efficiency. The masks could be tracked within the 18 × 14 mm lateral displacement and up to 12° tilt. Two patient cases are demonstrated. No complications were observed during the surgery, although it needs some attention for aligning the mask horizontally before trephination. Stability of eye tracking masks is emphasized by inducing on purpose movements of the patient head. Conclusion: Eye-tracking-guided penetrating keratoplasty was successfully applied in clinical practice, which enables robust tracking criteria within an extended range. It facilitates the automated trephination procedure of excimer laser-assisted penetrating keratoplasty.

  1. Eye-Tracker-Guided Non-Mechanical Excimer Laser Assisted Penetrating Keratoplasty

    Science.gov (United States)

    Janunts, Edgar; Schirra, Frank; Szentmáry, Nora; Seitz, Berthold; Langenbucher, Achim

    2013-01-01

    Purpose: The purpose of the study was to implement a new eye tracking mask which could be used to guide the laser beam in automated non-mechanical excimer laser assisted penetrating keratoplasty. Materials and methods: A new trephination mask design with an elevated surface geometry has been proposed with a step formation between conical and flat interfaces. Two recipient masks of 7.5/8.0 mm have been manufactured and tested. The masks have outer diameter of 12.5 mm, step formation at 10.5 mm, and slope of conical surfaces 15°. Its functionality has been tested in different lateral positions and tilts on a planar surface, and pig eye experiments. After successful validation on porcine eyes, new masks have been produced and tested on two patients. Results: The build-in eye tracking software of the MEL 70 was always able to capture the masks. It has been shown that the unwanted pigmentation/pattern induced by the laser pulses on the mask surface does not influence the eye-tracking efficiency. The masks could be tracked within the 18 × 14 mm lateral displacement and up to 12° tilt. Two patient cases are demonstrated. No complications were observed during the surgery, although it needs some attention for aligning the mask horizontally before trephination. Stability of eye tracking masks is emphasized by inducing on purpose movements of the patient head. Conclusion: Eye-tracking-guided penetrating keratoplasty was successfully applied in clinical practice, which enables robust tracking criteria within an extended range. It facilitates the automated trephination procedure of excimer laser-assisted penetrating keratoplasty. PMID:23507821

  2. Resident surgeon efficiency in femtosecond laser-assisted cataract surgery

    Science.gov (United States)

    Pittner, Andrew C; Sullivan, Brian R

    2017-01-01

    Purpose Comparison of resident surgeon performance efficiencies in femtosecond laser-assisted cataract surgery (FLACS) versus conventional phacoemulsification. Patients and methods A retrospective cohort study was conducted on consecutive patients undergoing phacoemulsification cataract surgery performed by senior ophthalmology residents under the supervision of 1 attending physician during a 9-month period in a large Veterans Affairs medical center. Medical records were reviewed for demographic information, preoperative nucleus grade, femtosecond laser pretreatment, operative procedure times, total operating room times, and surgical complications. Review of digital video records provided quantitative interval measurements of core steps of the procedures, including completion of incisions, anterior capsulotomy, nucleus removal, cortical removal, and intraocular lens implantation. Results Total room time, operation time, and corneal incision completion time were found to be significantly longer in the femtosecond laser group versus the traditional phacoemulsification group (each Pcataract surgery is generally less efficient when trainees have more experience with traditional phacoemulsification. FLACS was found to have a significant advantage in completion of capsulotomy, but subsequent surgical steps were not shorter or longer. Resident learning curve for the FLACS technology may partially explain the disparities of performance. Educators should be cognizant of a potential for lower procedural efficiency when introducing FLACS into resident training. PMID:28203055

  3. Posterior Corneal Surface Stability after Femtosecond Laser-Assisted Keratomileusis

    Directory of Open Access Journals (Sweden)

    Carlo Cagini

    2015-01-01

    Full Text Available The purpose of this study was to evaluate posterior corneal surface variation after femtosecond laser-assisted keratomileusis in patients with myopia and myopic astigmatism. Patients were evaluated by corneal tomography preoperatively and at 1, 6, and 12 months. We analyzed changes in the posterior corneal curvature, posterior corneal elevation, and anterior chamber depth. Moreover, we explored correlation between corneal ablation depth, residual corneal thickness, percentage of ablated corneal tissue, and preoperative corneal thickness. During follow-up, the posterior corneal surface did not have a significant forward corneal shift: no significant linear relationships emerged between the anterior displacement of the posterior corneal surface and corneal ablation depth, residual corneal thickness, or percentage of ablated corneal tissue.

  4. Resident surgeon efficiency in femtosecond laser-assisted cataract surgery

    Directory of Open Access Journals (Sweden)

    Pittner AC

    2017-01-01

    Full Text Available Andrew C Pittner,1 Brian R Sullivan2 1Department of Ophthalmology, Stritch School of Medicine, Loyola University Chicago, Maywood, 2Edward Hines Jr VA Hospital, Ophthalmology Section, Hines, IL, USA Purpose: Comparison of resident surgeon performance efficiencies in femtosecond laser-assisted cataract surgery (FLACS versus conventional phacoemulsification.Patients and methods: A retrospective cohort study was conducted on consecutive patients undergoing phacoemulsification cataract surgery performed by senior ophthalmology residents under the supervision of 1 attending physician during a 9-month period in a large Veterans Affairs medical center. Medical records were reviewed for demographic information, preoperative nucleus grade, femtosecond laser pretreatment, operative procedure times, total operating room times, and surgical complications. Review of digital video records provided quantitative interval measurements of core steps of the procedures, including completion of incisions, anterior capsulotomy, nucleus removal, cortical removal, and intraocular lens implantation.Results: Total room time, operation time, and corneal incision completion time were found to be significantly longer in the femtosecond laser group versus the traditional phacoemulsification group (each P<0.05. Mean duration for manual completion of anterior capsulotomy was shorter in the laser group (P<0.001. There were no statistically significant differences in the individual steps of nucleus removal, cortical removal, or intraocular lens placement. Surgical complication rates were not significantly different between the groups.Conclusion: In early cases, resident completion of femtosecond cataract surgery is generally less efficient when trainees have more experience with traditional phacoemulsification. FLACS was found to have a significant advantage in completion of capsulotomy, but subsequent surgical steps were not shorter or longer. Resident learning curve for the

  5. The clinical results of femtosecond laser-assisted deep anterior lamellar keratoplasty in patients with keratoconus%飞秒激光辅助的深板层角膜移植术治疗圆锥角膜的初步临床研究

    Institute of Scientific and Technical Information of China (English)

    陆燕; 段娴艺; 陈祥菲; 葛轶睿; 杨丽萍; 黄振平

    2014-01-01

    spectacle-corrected visual acuity was 0.41 ± 0.35 (range,0.12-1.00).The donor corneal lamella diameters were 0.20 mm larger and thicker than the recipient to restore a physiologic corneal thickness and shape.Mean donor diameter was (7.8 ± 0.2) mm (range,7.3-8.0 mm) and mean thickness was (372 ± 40) μm (range,350-400 μm).Early postoperative evaluation showed a clear graft in all cases.Mean corneal thickness was (459 ± 36) μm(range,389-488 μm).At the last postoperative examination mean uncorrected visual acuity was 0.32 ± 0.19 (range,0.12-0.60),and the mean best corrected visual acuity was 0.58 ± 0.29 (range,0.20-1.00).The UCVA and BCVA improved significantly after surgery (t =-4.433,-3.348,P < 0.05).Conclusions Our early results indicate that femtosecond laser-assisted deep anterior lamellar keratoplasty shows promise as a safe and effective surgical choice in the treatment of keratoconus.

  6. Orientation teeth in nonmechanical femtosecond laser corneal trephination for penetrating keratoplasty.

    Science.gov (United States)

    Mastropasqua, Leonardo; Nubile, Mario; Lanzini, Manuela; Calienno, Roberta; Trubiani, Oriana

    2008-07-01

    To evaluate femtosecond laser-assisted corneal full-thickness trephination with orientation teeth and notches for penetrating keratoplasty (PKP). Interventional case series. Four eyes of four patients aged 34 to 55 years underwent PKP using a femtosecond laser system enabling corneal trephination with orientation teeth and notches. Patients were affected by advanced keratoconus (n = 2) or postinfectious corneal scar (n = 2). Scanning electron microscopy (SEM) was performed to evaluate the cut quality of donor and recipient cornea. All procedures were completed without any complications. In all cases, the donor and the recipient cornea were cut with the same size of 8.0-mm diameter. A complete perforating cut was achieved in all eyes, and a correct intraoperative matching of teeth and notches was obtained. SEM of donor and recipient specimens showed a full-thickness cut with smooth and regular shape of orientation teeth and notches. Orientation teeth and notches shaped PKP using the femtosecond laser technology is feasible and may offer further promising approaches toward customized trephination techniques.

  7. Microcapillary sign of flap alignment in femtosecond laser-assisted in situ keratomileusis

    Science.gov (United States)

    Fawzy, Fathy; Wahba, Sherine S; Fawzy, Nader

    2016-01-01

    We present an observational sign that ensures perfect alignment during femtosecond laser-assisted in situ keratomileusis (FS LASIK). Alignment is assured when a microsponge is used to dry the flap and the area of dryness exceeds the area of direct touch of the microsponge. The area might even reach the whole circumference of the flap at the first touch. This sign of alignment can be explained by microcapillary action. This sign was not elicited in flaps created by a microkeratome. PMID:27799731

  8. Femtosecond laser-assisted cataract surgery and implantable miniature telescope

    Directory of Open Access Journals (Sweden)

    Randal Pham

    2017-09-01

    Conclusions and importance: To our knowledge and confirmed by the manufacturer of the implantable miniature telescope this is the first case ever reported of a patient who has undergone femtosecond laser cataract surgery with corneal astigmatism correction and implantation of the implantable miniature telescope. This is also the first case report of the preoperative use of microperimetry and visual electrophysiology to evaluate a patient's postoperative potential visual acuity. The success of the procedure illustrated the importance of meticulous preoperative planning, the combined use of state-of-the-art technologies and the seamless teamwork in order to achieve the best clinical outcome for patients who undergo implantation of the implantable miniature telescope.

  9. Penetrating Keratoplasty for Keratoconus - Excimer Versus Femtosecond Laser Trephination.

    Science.gov (United States)

    Seitz, Berthold; Langenbucher, Achim; Hager, Tobias; Janunts, Edgar; El-Husseiny, Moatasem; Szentmáry, Nora

    2017-01-01

    In case of keratoconus, rigid gas-permeable contact lenses as the correction method of first choice allow for a good visual acuity for quite some time. In a severe stage of the disease with major cone-shaped protrusion of the cornea, even specially designed keratoconus contact lenses are no more tolerated. In case of existing contraindications for intrastromal ring segments, corneal transplantation typically has a very good prognosis. In case of advanced keratoconus - especially after corneal hydrops due to rupture of Descemet's membrane - penetrating keratoplasty (PKP) still is the surgical method of first choice. Noncontact excimer laser trephination seems to be especially beneficial for eyes with iatrogenic keratectasia after LASIK and those with repeat grafts in case of "keratoconus recurrences" due to small grafts with thin host cornea. For donor trephination from the epithelial side, an artificial chamber is used. Wound closure is achieved with a double running cross-stitch suture according to Hoffmann. Graft size is adapted individually depending on corneal size ("as large as possible - as small as necessary"). Limbal centration will be preferred intraoperatively due to optical displacement of the pupil. During the last 10 years femtosecond laser trephination has been introduced from the USA as a potentially advantageous approach. Prospective clinical studies have shown that the technique of non-contact excimer laser PKP improves donor and recipient centration, reduces "vertical tilt" and "horizontal torsion" of the graft in the recipient bed, thus resulting in significantly less "all-sutures-out" keratometric astigmatism (2.8 vs. 5.7 D), higher regularity of the topography (SRI 0.80 vs. 0.98) and better visual acuity (0.80 vs. 0.63) in contrast to the motor trephine. The stage of the disease does not influence functional outcome after excimer laser PKP. Refractive outcomes of femtosecond laser keratoplasty, however, resemble that of the motor trephine. In

  10. Penetrating Keratoplasty for Keratoconus – Excimer Versus Femtosecond Laser Trephination

    Science.gov (United States)

    Seitz, Berthold; Langenbucher, Achim; Hager, Tobias; Janunts, Edgar; El-Husseiny, Moatasem; Szentmáry, Nora

    2017-01-01

    Background: In case of keratoconus, rigid gas-permeable contact lenses as the correction method of first choice allow for a good visual acuity for quite some time. In a severe stage of the disease with major cone-shaped protrusion of the cornea, even specially designed keratoconus contact lenses are no more tolerated. In case of existing contraindications for intrastromal ring segments, corneal transplantation typically has a very good prognosis. Methods: In case of advanced keratoconus – especially after corneal hydrops due to rupture of Descemet’s membrane – penetrating keratoplasty (PKP) still is the surgical method of first choice. Noncontact excimer laser trephination seems to be especially beneficial for eyes with iatrogenic keratectasia after LASIK and those with repeat grafts in case of “keratoconus recurrences” due to small grafts with thin host cornea. For donor trephination from the epithelial side, an artificial chamber is used. Wound closure is achieved with a double running cross-stitch suture according to Hoffmann. Graft size is adapted individually depending on corneal size („as large as possible – as small as necessary“). Limbal centration will be preferred intraoperatively due to optical displacement of the pupil. During the last 10 years femtosecond laser trephination has been introduced from the USA as a potentially advantageous approach. Results: Prospective clinical studies have shown that the technique of non-contact excimer laser PKP improves donor and recipient centration, reduces “vertical tilt” and “horizontal torsion” of the graft in the recipient bed, thus resulting in significantly less “all-sutures-out” keratometric astigmatism (2.8 vs. 5.7 D), higher regularity of the topography (SRI 0.80 vs. 0.98) and better visual acuity (0.80 vs. 0.63) in contrast to the motor trephine. The stage of the disease does not influence functional outcome after excimer laser PKP. Refractive outcomes of femtosecond laser

  11. Microcapillary sign of flap alignment in femtosecond laser-assisted in situ keratomileusis

    Directory of Open Access Journals (Sweden)

    Fawzy F

    2016-10-01

    Full Text Available Fathy Fawzy,1,2 Sherine S Wahba,1,3 Nader Fawzy1,4 1Al Watany Eye Hospital, 2Ophthalmology Department, Military Medical Academy, 3Ophthalmology Department, Ain Shams University, Cairo, Egypt; 4Sehkraft Augenzentrum, Cologne, Germany Abstract: We present an observational sign that ensures perfect alignment during femtosecond laser-assisted in situ keratomileusis (FS LASIK. Alignment is assured when a microsponge is used to dry the flap and the area of dryness exceeds the area of direct touch of the microsponge. The area might even reach the whole circumference of the flap at the first touch. This sign of alignment can be explained by microcapillary action. This sign was not elicited in flaps created by a microkeratome. Keywords: capillarity, femtosecond LASIK flap, corneal flap alignment

  12. Comparing the intraoperative complication rate of femtosecond laser-assisted cataract surgery to traditional phacoemulsification

    Institute of Scientific and Technical Information of China (English)

    Ming; Chen; Christian; Swinney; Mindy; Chen

    2015-01-01

    AIM: To compare the complication rate of femtosecond laser-assisted cataract surgery(FLACS) and traditional phacoemulsification for the first 18 mo of FLACS use at a private surgical center in Hawaii.METHODS: A retrospective chart review was conducted from January 2012 to June 2013. The first 273 consecutive eyes receiving FLACS and 553 eyes receiving traditional phacoemulsification were examined.All surgeries were performed at a single surgical center in Hawaii. The presence of intraoperative complications was used as the main outcome measure. Approval was obtained from the institutional review board of the University of Hawaii.RESULTS: The overall complication rate for FLACS was 1.8%, while that of the traditional procedure was5.8%(P <0.05). A majority of the surgeons(80%) had a lower complication rate while using FLACS.CONCLUSION: FLACS is comparable in safety, if not safer, than traditional cataract surgery when performed by qualified cataract surgeons on carefully selected patients.

  13. Comparing the intraoperative complication rate of femtosecond laser-assisted cataract surgery to traditional phacoemulsification

    Directory of Open Access Journals (Sweden)

    Ming Chen

    2015-02-01

    Full Text Available AIM: To compare the complication rate of femtosecond laser-assisted cataract surgery (FLACS and traditional phacoemulsification for the first 18mo of FLACS use at a private surgical center in Hawaii. METHODS: A retrospective chart review was conducted from January 2012 to June 2013. The first 273 consecutive eyes receiving FLACS and 553 eyes receiving traditional phacoemulsification were examined. All surgeries were performed at a single surgical center in Hawaii. The presence of intraoperative complications was used as the main outcome measure. Approval was obtained from the institutional review board of the University of Hawaii. RESULTS: The overall complication rate for FLACS was 1.8%, while that of the traditional procedure was 5.8% (PCONCLUSION: FLACS is comparable in safety, if not safer, than traditional cataract surgery when performed by qualified cataract surgeons on carefully selected patients.

  14. Suction loss during femtosecond laser-assisted small-incision lenticule extraction: Incidence and analysis of risk factors.

    Science.gov (United States)

    Osman, Ihab M; Awad, Ramy; Shi, Wei; Abou Shousha, Mohamed

    2016-02-01

    To determine the incidence of and analyze risk factors for suction loss during femtosecond laser-assisted small incision lenticule extraction in the management of myopia or myopic astigmatism. Roayah Vision Correction Center, Alexandria, Egypt. Retrospective comparative case-control study. All eyes that had femtosecond laser-assisted small-incision lenticule extraction for the correction of myopia and myopic astigmatism performed between August 2010 and April 2014 were included. Eyes that developed suction loss were identified. Their characteristics, including demographic data (age and sex), eye laterality, manifest refraction, flat keratometry (K) reading, steep K reading, K astigmatism, optical zone, central corneal thickness, and corneal cap diameter and thickness, were compared with those in randomly selected control eyes to determine the risk factors for developing suction loss. Of the 3376 eyes that had femtosecond laser-assisted small-incision lenticule extraction during the study, 70 (2.1%) developed loss of suction. The incidence decreased with surgical experience (5.06% in 2010, 3.59% in 2011, 3.41% in 2012, 2.32% in 2013, and 1.84% in 2014), suggesting a learning curve. A multivariate logistic regression model showed that eyes with a larger cap diameter were significantly more likely to develop suction loss (P = .023; odds ratio, 9.60). Surgical experience significantly decreased the risk for suction loss during femtosecond laser-assisted small incision lenticule extraction for the correction of myopia or myopic astigmatism but did not eliminate it. A larger cap diameter significantly increased the risk for developing the suction loss. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  15. Laser assisted bioprinting using a femtosecond laser with and without a gold transductive layer: a parametric study

    Science.gov (United States)

    Desrus, H.; Chassagne, B.; Catros, S.; Artiges, C.; Devillard, R.; Petit, S.; Deloison, F.; Fricain, J. C.; Guillemot, F.; Kling, R.

    2016-03-01

    Experimental results of femtosecond Laser Assisted Bioprinting (LAB) are reported on. Two set-up, used to print different model bioinks and keratinocytes cells line HaCaT, were studied: first one was using a femtosecond laser with low pulse energy and an absorbing gold layer, whereas the second one used high pulse energy enabling the removal of the absorbing layer. Printed drop diameter and resulting height of the bioink jet are then quantified as a function of the LAB parameters such as laser energy, focus spot location or numerical aperture.

  16. Tomographic Analysis of Anterior and Posterior and Total Corneal Refractive Power Changes After Femtosecond Laser-Assisted Keratotomy.

    Science.gov (United States)

    Löffler, Franziska; Böhm, Myriam; Herzog, Michael; Petermann, Kerstin; Kohnen, Thomas

    2017-08-01

    To analyze the effect of penetrating femtosecond laser-assisted keratotomy (pFLAK) during laser lens surgery on anterior and posterior corneal astigmatism and total corneal refractive power (TCRP) astigmatism (CAant, CApost, CATCRP) measured with Scheimpflug tomography. Prospective, interventional case series. This institutional study included 27 eyes of 23 patients (aged 65 ± 8 years) with low-to-moderate CATCRP determined with Scheimpflug tomography (Pentacam HR; Oculus, Wetzlar, Germany) after penetrating femtosecond laser-assisted keratotomy (pFLAK) and laser lens surgery. The CAant, CApost, and CATCRP were determined before and 1 and 3 months after surgery. Vector analysis according to the Alpins method was used to calculate surgically induced astigmatism (SIA). The mean preoperative CAant (0.97 ± 0.30 diopter [D]) was significantly reduced to 0.63 ± 0.34 D (P low (0.12 ± 0.07 D). The CATCRP showed similar results as CAant. pFLAKs planned according to Scheimpflug-based CATCRP result in a significant reduction of the CAant and CATCRP, but do not affect the posterior corneal curvature significantly, as measured by Scheimpflug tomography. Further research is required to develop a new valid nomogram for laser-assisted lens surgery. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Reversible Femtosecond Laser-Assisted Endokeratophakia Using Cryopreserved Allogeneic Corneal Lenticule.

    Science.gov (United States)

    Sun, Yuan; Zhang, Ting; Zhou, Yuehua; Liu, Manli; Zhou, Yugui; Yang, Xiaonan; Weng, Shengbei; To, Chi-Ho; Liu, Quan

    2016-08-01

    To evaluate outcomes, reversibility, and wound healing response after the femtosecond laser-assisted endokeratophakia procedure in a rabbit model. Allogeneic rabbit corneal lenticules were cryopreserved in liquid nitrogen for 3 months. Twenty rabbits underwent the monocular endokeratophakia procedure and were divided into four groups according to the follow-up periods. The first three groups were killed at 3 days, 2 weeks, and 6 months after endokeratophakia, respectively. The rabbits in the fourth group received re-extraction of implanted lenticules at 6 months after endokeratophakia and were killed at 1 month after re-extraction. The rabbits were monitored by slit-lamp microscopy, ultrasonic pachymetry, in vivo confocal microscopy, optical coherence tomography (OCT), Corvis ST tonometry (Oculus Optikgeräte, Wetzlar, Germany), and Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, NY). The tissue responses were analyzed by immunohistochemistry and transmission electron microscopy. After endokeratophakia, corneal clarity improved continually with time. The changes in the refraction and corneal thickness were stable after implantation and could be reversed after re-extracting the lenticules. The interfaces were clearly visible on confocal microscopy and transmission electron microscopy images over the entire follow-up period. There were significant numbers of TUNEL-positive keratocytes in lenticules after endokeratophakia. CD11b-positive cells and deposition of fibronectin and tenascin were observed at earlier follow-up times. No alpha-smooth muscle actin-positive fibroblasts could be detected. In addition, the corneal biomechanics parameters were not significantly increased after endokeratophakia. The endokeratophakia procedure using allogeneic cryopreserved lenticules was clinically stable and could be reversed. The wound healing response was mild, limited, and produced no scars. [J Refract Surg. 2016;32(8):569-576.]. Copyright 2016, SLACK

  18. Top-hat shaped corneal trephination for penetrating keratoplasty using the femtosecond laser: a histomorphological study.

    Science.gov (United States)

    Kook, Daniel; Derhartunian, Victor; Bug, Reinhold; Kohnen, Thomas

    2009-08-01

    To evaluate a novel technique for penetrating keratoplasty (PK) with the use of a new software algorithm for the femtosecond laser, designed to create penetrating cuts in a top hat configuration. Consecutive histomorphological case series. Twelve eyes of 12 patients underwent penetrating keratoplasty by means of a 60-kHz femtosecond laser (IntraLase, Irvine, California) with a software specifically developed for corneal surgery. Of the 12 patients, the reason for keratoplasty was keratoconus in 4 patients, bullous keratopathy in 6 patients, keratotorus in 1 patient, and status post chemical burn in 1 patient. A new software was used to create penetrating cuts in a top-hat-shaped configuration. In all cases, cutting parameters were identical in all donor and corresponding host corneas: 7.0 mm diameter of the anterior side cut, 8.5-8.7 mm diameter of the posterior side cut, and a depth of 300 microm for the lamellar cut. In all cases, a complete penetrating cut with the laser in the host cornea was not intended intraoperatively. Complete penetration was performed subsequently and manually with a diamond knife because of logistic conditions. Trephined corneoscleral rings and button corneas were analyzed macroscopically and histologically to determine cut quality. All procedures were performed without any complications. With application of appropriate combinations of pulse energy and spacing, trephination took less than 200 seconds. Macroscopic examination and histology of donor and recipient specimens showed a straight, smooth cut with perpendicular edges in all donor buttons. No corneal edema and no visible damage to the keratocyte nuclei were found. At the region of manual dissection, a small stromal tissue-tag was present in parts of the circumference in all donor buttons. No evidence of any cut complication was noted. Top-hat-shaped penetrating keratoplasty using the IntraLase femtosecond laser enables a quick and sufficient trephination of both human donor and

  19. Morphologic and histopathologic changes in the rabbit cornea produced by femtosecond laser-assisted multilayer intrastromal ablation.

    Science.gov (United States)

    Zhang, Zhen-Yong; Chu, Ren-Yuan; Zhou, Xing-Tao; Dai, Jin-Hui; Sun, Xing-Huai; Hoffman, Matthew R; Zhang, Xing-Ru

    2009-05-01

    To observe morphologic and histopathologic changes in the midperiphery of the rabbit cornea produced by femtosecond laser-assisted multilayer intrastromal ablation, determine whether this method may be used to correct myopia, and study how the cornea heals when the epithelium is not injured. The right eyes of 10 New Zealand White rabbits were used for the experiments. A 60-kHz femtosecond laser delivery system was used, and three lamellar layers of laser pulses were focused starting at a corneal depth of 180 microm and ending at 90 microm from the surface, with each successive layer placed 45 microm anterior to the previous layer. In the interface of the applanation contact lens cone, a 6-mm diameter aluminum circle was placed at the center to block the laser, and ablation was limited to the midperiphery of the cornea. The laser settings were spot/line separation, 10 microm; diameter, 8.5 mm; energy for ablating the stroma, 1.3 microJ. Topography examination was used to document changes in corneal power. Light microscopy, transmission electron microscopy (TEM), and confocal microscopy in vivo were applied to observe changes in the cornea. There was significant change in mean corneal power between baseline and postoperative month 3 (n = 8; P = 0.0001), with a decrease from 46.82 D to 44.42 D. There was no haze formation or refractive regression throughout the follow-up. There were no corneal structural abnormalities under light microscopy. Activated keratocytes and necrotic debris were visible under confocal microscopy. Fibroblasts were observed, and no myofibroblasts appeared under TEM. Multilayer intrastromal ablation by the femtosecond laser with intact epithelium in the midperiphery of the corneal stroma can flatten the cornea without causing haze formation or refractive regression. This procedure allows the cornea to heal differently than when traditional corneal refractive surgery is performed and the epithelium is damaged.

  20. [Femtosecond laser-assisted lens surgery depending on interface design and laser pulse energy: results of the first 200 cases].

    Science.gov (United States)

    Mayer, W J; Klaproth, O K; Ostovic, M; Hengerer, F H; Kohnen, T

    2014-12-01

    This study was designed to evaluate the effectiveness and safety of femtosecond laser-assisted lens surgery depending on interface design and laser pulse energy settings. In this non-randomized, consecutive case series200 eyes underwent femtosecond laser-assisted (LenSx, Alcon) lens surgery between November 2012 and June 2013. Group 1 consisted of 85 eyes with 60 cataracts and 25 refractive lens exchanges (RLE) which were treated with a curved direct contact interface, and group 2 consisting of 115 eyes with 72 cataracts and 43 RLEs treated with a modified interface using an additional soft contact lens (SoftFit™, Alcon) between the corneal surface and the interface. The degree of opacity of the lens in cataract eyes was measured with a Scheimpflug camera. Afterwards, phacoemulsification was performed with intraocular lens (IOL) implantation in all eyes. Primary endpoints were the effective phacoemulsification time (EPT), the average laser treatment time and the occurrence of intraoperative complications. The mean EPT in group 1 was 1.62 ± 1.12 s (cataract 1.94 ± 1.31 s, RLE 1.29 ± 1.01 s) and in group 2 the mean EPT was 1.66 ± 0.92 s (cataract 1.98 ± 1.28 s, RLE 1.33 ± 1.22 s, p = 0.32 between groups). The laser treatment lasted on average 48.90 ± 2.45 s (group 1) and 49.70 ± 2.87 s (group 2) with an average lens fragmentation thickness of 3401.48 ± 401.12 µm (all groups). In four cases of group 1, a second applanation of the interface was necessary. Furthermore, one anterior capsule tear, 39 cases of intraoperative wrinkling of the corneal surface and 21 cases in which the corneal incision had to be opened manually were documented in group 1. In group 2 no second applanation of the interface, no anterior capsule tears and no corneal wrinkling but 9 cases with a manual opening of corneal incisions were documented (p interface and reduced laser pulse energy.

  1. Corneal biomechanical properties after femtosecond laser assisted LASIK with the corneal visualization Scheimpflug technology and ocular response analyzer

    Directory of Open Access Journals (Sweden)

    Jing Li

    2017-02-01

    Full Text Available AIM: To investigate the changes of corneal biomechanical properties before and after femtosecond laser assisted LASIK(FS-LASIKusing Corneal Visualisation Scheimpflug Technology(Corvis STand Ocular Response Analyzer(ORA, and the correlation with other myopic parameters. METHODS:Sixty three patients(63 eyeswho had myopic femtosecond laser assisted LASIK(FS-LASIKwere enrolled in the study. The right eye of each patient was analyzed in this study. The corneal biomechanical parameters pre-operative and 1mo post-operative was measured with the Corvis ST(Oculus, Wetzlar, Germanyand ORA(Reichert, Buffalo, New York, USA. Comparison of the biomechanical property values before and after surgery was peformed using Paired t-test or Mann-Whitney U. Pearson or Spearman correlations were used to evaluate the relationship between parameters.RESULTS: The postoperative 1st A-time, Vin, 2nd A length, Vout, HC time and Radius demonstrate significant decreases comparing with preoperative values(P=0.00, P=0.00, P=0.00, P=0.00, P=0.00, P=0.00 respectively. The postoperative 2nd A-time, DA and PD significantly increases(P=0.00, P=0.00, P=0.00, however, the 1st A length had no significant difference after surgery. The CH and CRF were significantly lower after FS-LASIK(P=0.00, P=0.00. A statistically significant correlation coefficient was found between preoperative central corneal thickness(CCTwith postoperative-preoperative changes of 1st A-time, 2nd A-time, DA and Radius respectively(P=0.01, P=0.04, P=0.03, P=0.01. CONCLUSION:There were significantly changes of corneal biomechanical properties after FS-LASIK surgery. The changes of corneal biomechanical properties after FS-LASIK can be reflected by some parameters of Corvis ST and ORA. The mainly influence of corneal biomechanical alteration was possibly correlation with corneal thickness.

  2. Femtosecond laser assisted 3-dimensional freeform fabrication of metal microstructures in fused silica (Conference Presentation)

    Science.gov (United States)

    Ebrahim, Fatmah; Charvet, Raphaël.; Dénéréaz, Cyril; Mortensen, Andreas; Bellouard, Yves

    2017-03-01

    Femtosecond laser exposure of fused silica combined with chemical etching has opened up new opportunities for three-dimensional freeform processing of micro-structures that can form complex micro-devices of silica, integrating optical, mechanical and/or fluidic functionalities. Here, we demontrate an expansion of this process with an additional fabrication step that enables the integration of three-dimensional embedded metallic structures out of useful engineering metals such as silver, gold, copper as well as some of their alloys. This additional step is an adaptation of the pressure infiltration for the insertion of high conductivity, high melting point metals and alloys into topologically complex, femtosecond laser-machined cavities in fused silica. This produces truly 3-dimensional microstructures, including microcoils and needles, within the bulk of glass substrates. Combining this added capability with the existing possibilities of femtosecond laser micromachining (i.e. direct written waveguides, microchannels, resonators, etc.) opens up a host of potential applications for the contactless fabrication of highly integrated monolithic devices that include conductive element of all kind. We present preliminary results from this new fabrication process, including prototype devices that incorporate 3D electrodes with aspect ratios of 1:100 and a feature size resolution down to 2μm. We demonstrate the generation of high electric field gradients (of the order of 1013 Vm-2) in these devices due to the 3-dimensional topology of fabricated microstructures.

  3. Endothelial cell loss and refractive predictability in femtosecond laser-assisted cataract surgery compared with conventional cataract surgery

    DEFF Research Database (Denmark)

    Krarup, Therese; Holm, Lars Morten; la Cour, Morten

    2014-01-01

    preoperatively, 1-3 days postoperatively and 3 months postoperatively. RESULTS: Three days postoperatively, mean ECL was 249 cells/mm(2) (SD ± 744) (9.1%) by FLACS and 235 cells/mm(2) (SD ± 681) (8.2%) by CPS (p = 0.87). Three months postoperatively, mean ECL was 274 cells/mm(2) (SD ± 358) (11.4%) by FLACS......PURPOSE: To investigate the amount of endothelial cell loss (ECL) and refractive predictability by femtosecond laser-assisted cataract surgery (FLACS) compared to conventional phacoemulsification cataract surgery (CPS). METHODS: Forty-seven patients had one eye operated by FLACS...... compared with 333 cells/mm(2) (SD ± 422) (13.9%) by CPS, (p = 0.30) 3 months postoperatively, hexagonality was decreased by 1.8% (SD ± 30) by FLACS and by 1.4% (SD ± 13) by CPS, (p = 0.84). The mean absolute difference from the attempted refraction was 0.37 dioptres (D) (SD ± 0.33) by FLACS and 0.41 D (SD...

  4. Combined femtosecond laser-assisted intracorneal ring segment implantation and corneal collagen cross-linking for correction of keratoconus

    Directory of Open Access Journals (Sweden)

    Ibrahim O

    2016-03-01

    Full Text Available Osama Ibrahim,1 Ahmed Elmassry,1 Amr Said,1,2 Moones Abdalla,2 Hazem El Hennawi,1 Ihab Osman1 1Department of Ophthalmology, Alexandria University, Alexandria, Egypt; 2Roayah Vision Correction Center, Alexandria, Egypt Purpose: To assess the safety, predictability, and effectiveness of Keraring intrastromal corneal ring segments (ICRS insertion assisted by femtosecond laser and corneal collagen cross-linking (CXL for keratoconus correction. Patients and methods: In this prospective, noncomparative, and interventional case series, 160 eyes of 100 adult keratoconus patients with poor best-corrected visual acuity (BCVA (less than 0.7 and intolerance to contact lens wear were included. Patients underwent femtosecond laser-assisted placement of ICRS and CXL. All patients were examined for a complete ophthalmological test: uncorrected visual acuity (UCVA, BCVA, spherical equivalent, keratometry (K1-flat and K2-steep, pachymetry, and Scheimpflug imaging with the Pentacam at 1 week and at 1, 3, and 6 months postoperatively. Results: At 6 months, a significant difference was observed (P<0.001 in mean UCVA and BCVA from 0.92±0.677 and 0.42±0.600 logMAR preoperatively to 0.20±0.568 and 0.119±0.619 logMAR, respectively. Mean spherical equivalent refractions were significantly lower (P<0.001 at 6 months. Mean keratometry (K also significantly reduced (P<0.001 from 50.93±5.53 D (K1-flat and 55.37±5.76 D (K2-steep to 47.32±4.61 and 51.08±5.38 D, respectively. In terms of pachymetry, no significant difference was observed preoperatively versus postoperatively (P=1.000. Conclusion: Keraring ICRS insertion assisted by femtosecond laser and corneal CXL provided significant improvement in visual acuity, spherical equivalent, and keratometry, which suggests that it may be effective, safe, and predictable for keratoconus correction. Keywords: keratometry, pachymetry, keratectesia, Pentacam, irregular astigmatism

  5. Blood pressure change during phacoemulsification and femtosecond laser-assisted cataract surgery

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    Hung-Yuan Lin

    2016-11-01

    Full Text Available AIM: To evaluate blood pressure (BP changes during phacoemulsification (PC and femtosecond laser (FSL-assisted cataract surgery. METHODS: A retrospective chart review was performed for all patients who received traditional phacoemulsification surgery (PC group and FSL-assisted cataract surgery (FS group from July 2013 to December 2014. Totally 206 eyes from 133 patients receiving the two types of procedures were included. Patient characteristics (age, gender, and hypertension history, pre- and post-operative BPs were collected. RESULTS: The pro-operative systolic and diastolic BPs (mm Hg were 124.89±20.48 vs 126.98±16.85, and 71.88±9.81 vs 73.56±10.03, in PC and FS groups, respectively. While the post-operative systolic and diastolic BPs (mm Hg were 130.13±22.59 vs 134.77±17.52, and 73.41±11.62 vs 78.89±12.2, in PC and FS groups, respectively. Paired-sample t-tests showed obvious systolic and diastolic BP elevations in FS group after surgery (P=0.001 and 0.007 and no reliability in PC group (P=0.094 and 0.359. A linear regression model revealed systolic and diastolic BP elevations, which were related to longer surgical times for FS group (P=0.008 and 0.021. Age, gender, and hypertension history were not correlated with blood pressure elevation in either group. CONCLUSION: BP increases but at a limited level after FSL-assisted cataract surgery compared to traditional phacoemulsificationKEYWORDS: cataract surgery; blood pressure; femtosecond-assisted cataract surgery; phacoemulsification

  6. Analysis of femtosecond laser assisted capsulotomy cutting edges and manual capsulorhexis using environmental scanning electron microscopy.

    Science.gov (United States)

    Serrao, Sebastiano; Lombardo, Giuseppe; Desiderio, Giovanni; Buratto, Lucio; Schiano-Lomoriello, Domenico; Pileri, Marco; Lombardo, Marco

    2014-01-01

    Purpose. To investigate the structure and irregularity of the capsulotomy cutting edges created by two femtosecond (FS) laser platforms in comparison with manual continuous circular capsulorhexis (CCC) using environmental scanning electron microscopy (eSEM). Methods. Ten anterior capsulotomies were obtained using two different FS laser cataract platforms (LenSx, n = 5, and Victus, n = 5). In addition, five manual CCC (n = 5) were obtained using a rhexis forceps. The specimens were imaged by eSEM (FEI Quanta 400, OR, USA). Objective metrics, which included the arithmetic mean deviation of the surface (Sa) and the root-mean-square deviation of the surface (Sq), were used to evaluate the irregularity of both the FS laser capsulotomies and the manual CCC cutting edges. Results. Several microirregularities were shown across the FS laser capsulotomy cutting edges. The edges of manually torn capsules were shown, by comparison of Sa and Sq values, to be smoother (P laser capsulotomy edges. Conclusions. Work is needed to understand whether the FS laser capsulotomy edge microirregularities, not seen in manual CCC, may act as focal points for the concentration of stress that would increase the risk of capsular tear during phacoemulsification as recently reported in the literature.

  7. Comparison of Maximum Stretch Forces between Femtosecond Laser-Assisted Capsulotomy and Continuous Curvilinear Capsulorhexis.

    Science.gov (United States)

    Takagi, Mari; Kojima, Takashi; Ichikawa, Kei; Tanaka, Yoshiki; Kato, Yukihito; Horai, Rie; Tamaoki, Akeno; Ichikawa, Kazuo

    2017-01-01

    The current study reports comparing the postoperative mechanical properties of the anterior capsule between femtosecond laser capsulotomy (FLC) and continuous curvilinear capsulorhexis (CCC) of variable size and shape in porcine eyes. All CCCs were created using capsule forceps. Irregular or eccentric CCCs were also created to simulate real cataract surgery. For FLC, capsulotomies 5.3 mm in diameter were created using the LenSx® (Alcon) platform. Fresh porcine eyes were used in all experiments. The edges of the capsule openings were pulled at a constant speed using two L-shaped jigs. Stretch force and distance were recorded over time, and the maximum values in this regard were defined as those that were recorded when the capsule broke. There was no difference in maximum stretch force between CCC and FLC. There were no differences in circularity between FLC and same-sized CCC. However, same-sized CCC did show significantly higher maximum stretch forces than FLC. Teardrop-shaped CCC showed lower maximum stretch forces than same-sized CCC and FLC. Heart-shaped CCC showed lower maximum stretch forces than same-sized CCC. Conclusively, while capsule edge strength after CCC varied depending on size or irregularities, FLC had the advantage of stable maximum stretch forces.

  8. Analysis of Femtosecond Laser Assisted Capsulotomy Cutting Edges and Manual Capsulorhexis Using Environmental Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Sebastiano Serrao

    2014-01-01

    Full Text Available Purpose. To investigate the structure and irregularity of the capsulotomy cutting edges created by two femtosecond (FS laser platforms in comparison with manual continuous circular capsulorhexis (CCC using environmental scanning electron microscopy (eSEM. Methods. Ten anterior capsulotomies were obtained using two different FS laser cataract platforms (LenSx, n=5, and Victus, n=5. In addition, five manual CCC (n=5 were obtained using a rhexis forceps. The specimens were imaged by eSEM (FEI Quanta 400, OR, USA. Objective metrics, which included the arithmetic mean deviation of the surface (Sa and the root-mean-square deviation of the surface (Sq, were used to evaluate the irregularity of both the FS laser capsulotomies and the manual CCC cutting edges. Results. Several microirregularities were shown across the FS laser capsulotomy cutting edges. The edges of manually torn capsules were shown, by comparison of Sa and Sq values, to be smoother (P<0.05 than the FS laser capsulotomy edges. Conclusions. Work is needed to understand whether the FS laser capsulotomy edge microirregularities, not seen in manual CCC, may act as focal points for the concentration of stress that would increase the risk of capsular tear during phacoemulsification as recently reported in the literature.

  9. Penetrating keratoplasty using femtosecond laser-enabled keratoplasty with zig-zag incisions versus a mechanical trephine in patients with keratoconus.

    Science.gov (United States)

    Gaster, Ronald N; Dumitrascu, Oanna; Rabinowitz, Yaron S

    2012-09-01

    This paper will compare the visual outcomes of two different penetrating keratoplasty (PKP) techniques in patients with keratoconus. It is a retrospective comparative surgical case series of 116 keratoconus patients (137 eyes) who had PKP at the Cornea Eye Institute, Beverly Hills, California, USA. 56 keratoconus patients (66 eyes) underwent femtosecond laser-enabled keratoplasty (FLEK) with a zig-zag incision configuration. Their visual parameters were compared with those of 60 patients (71 eyes) who had traditional blade mechanical trephination PKP. The range of follow-up was between 3 and 6 months. The main outcome measures included uncorrected visual acuity and best spectacle-corrected visual acuity (BSCVA), manifest refractive spherical equivalent and topographically determined astigmatism. BSCVA was significantly better as early as 3 months postoperatively (p=0.001) in the FLEK group. Visual recovery to 20/40 after 3 months was significantly better in the FLEK group (p<0.001). Topographic astigmatism was lower in the FLEK group, but the difference between the two groups reached significance only at 3 months of follow-up (p=0.001). Postoperative complications noted were not different between the two groups. Faster visual recovery and better long-term outcomes were observed in keratoconus patients who had FLEK compared with those who had the mechanical PKP procedure with 6 months of postoperative follow-up.

  10. Interface quality of different corneal lamellar–cut depths for femtosecond laser–assisted lamellar anterior keratoplasty

    Science.gov (United States)

    Zhang, Chenxing; Bald, Matthew; Tang, Maolong; Li, Yan; Huang, David

    2015-01-01

    PURPOSE To evaluate interface quality of different corneal lamellar–cut depths with the femtosecond laser and determine a feasible range of depth for femtosecond laser–assisted lamellar anterior keratoplasty. SETTING Casey Eye Institute, Portland, Oregon, USA. DESIGN Experimental study. METHODS Full lamellar cuts were made on 20 deepithelialized human cadaver corneas using the femtosecond laser. The cut depth was 17% to 21% (100 μm), 31%, 35%, 38% to 40%, and 45% to 48% of the central stromal thickness. Scanning electron microscopy images of cap and bed surfaces were subjectively graded for ridge and roughness using a scale of 1 to 5 (1 = best). The graft–host match was evaluated by photography and optical coherence tomography in a simulated procedure. RESULTS The ridge score was correlated with the cut depth (P = .0078, R = 0.58) and better correlated with the percentage cut depth (P = .00024, R = 0.73). The shallowest cuts had the least ridges (score 1.25). The 31% cut depth produced significantly less ridges (score 2.15) than deeper cuts. The roughness score ranged from 2.19 to 3.08 for various depths. A simulated procedure using a 100 μm host cut and a 177 μm (31%) graft had a smooth interface and flush anterior junction using an inverted side-cut design. CONCLUSIONS The femtosecond laser produced more ridges in deeper lamellar cuts. A depth setting of 31% stromal thickness might produce adequate surface quality for femtosecond laser–assisted lamellar anterior keratoplasty. The inverted side-cut design produced good edge apposition even when the graft was thicker than the host lamellar–cut depth. PMID:25747165

  11. Quantum interference in laser-assisted photo-ionization excited by a femtosecond x-ray pulse

    Institute of Scientific and Technical Information of China (English)

    Ge Yu-Cheng

    2008-01-01

    The photoelectron energy spectra (PESs) excited by monochromatic femtosecond x-ray pulses in the presence of a femtosecond laser are investigated. APES is composed of a set of separate peaks, showing interesting comb-like structures. These structures result from the quantum interferences between photoelectron wave packets generated at different times. The width and the localization of each peak as well as the number of peaks are determined by all the laser and x-ray parameters. Most of peak heights of the PES are higher than the classical predictions.

  12. Comparison of intraocular pressure during the application of a liquid patient interface (FEMTO LDV Z8) for femtosecond laser-assisted cataract surgery using two different vacuum levels.

    Science.gov (United States)

    Ebner, Martina; Mariacher, Siegfried; Januschowski, Kai; Boden, Katrin; Seuthe, Anna-Maria; Szurman, Peter; Boden, Karl Thomas

    2017-08-01

    To evaluate intraocular pressure (IOP) using the application of a novel liquid patient interface for femtosecond laser-assisted cataract surgery with the FEMTO LDV Z8. IOP was evaluated in enucleated porcine eyes prior, during and after the application of the Femto LDV Z8 liquid patient interface (Ziemer Ophthalmic Systems, Switzerland) using intracameral cannulation (n=20), intravitreal cannulation (n=20), rebound tonometry (n=20) and indentation tonometry (n=20). Pressure was assessed prior vacuum, during vacuum (30 s, 1 min, 2 min, 3 min) and after releasing the vacuum (1 min and 2 min). Two groups with different predefined vacuum levels (350 mbar, 420 mbar) were investigated. Mean intracameral pressure (±SD) increased during vacuum application from 20 mm Hg to 52.00 mm Hg (±6.35mm Hg; p=0.005) and 45.18 mmHg (±4.34 mm Hg; p=0.005) for the 420 mbar and the 350 mbar vacuum levels, respectively. Mean intravitreal pressure increased from 20 mm Hg to 25.60 mm Hg (±9.85 mm Hg; p=0.058) and 28.10 mm Hg (±2.54 mm Hg; p=0.059) for the 420 mbar and the 350 mbar vacuum levels, respectively. Pressure values from indentation and rebound tonometry were in between intracameral and intravitreal values. Mean intracameral IOP was 18.1% higher (p=0.019) in the 420 mbar group compared with the 350 mbar group. During vacuum application of the liquid patient interface of the Femto LDV Z8 for femtosecond laser-assisted cataract surgery, IOP values were higher in the anterior chamber compared with the intravitreal pressure measurements. The higher predefined vacuum level (350 mbar vs 420 mbar) resulted in significant higher intracameral IOP. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  13. Corneal Backscatter Analysis by In Vivo Confocal Microscopy: Fellow Eye Comparison of Small Incision Lenticule Extraction and Femtosecond Laser-Assisted LASIK

    Directory of Open Access Journals (Sweden)

    Alper Agca

    2014-01-01

    Full Text Available Purpose. To evaluate and compare corneal backscatter from anterior stroma between small incision lenticule extraction (SMILE and femtosecond laser-assisted LASIK (femto-LASIK. Methods. A cohort of 60 eyes of 30 patients was randomized to receive SMILE in one eye and femto-LASIK in the fellow eye. In vivo confocal microscopy was performed at 1 week and 1, 3, and 6 months after surgery. The main outcome measurements were maximum backscattered intensity and the depth from which it was measured, the backscattered light intensity 30 μm below Bowman’s membrane at the flap interface and 150 μm below the superficial epithelium, and the number of refractive particles at the flap interface. Results. The mean backscattered light intensity (LI at all measured depths and the maximum backscattered LI were higher in the SMILE group than the femto-LASIK group at all postoperative visits. LI differences at 1 week and 1- and 3-month visits were statistically significant (P<0,05. LI differences at 6 months were not statistically significant. There was no difference in the number of refractive particles at the flap interface between the groups at any visit. Conclusions. SMILE results in increased backscattered LI in the anterior stroma when compared with femto-LASIK were evaluated.

  14. Comparison of the corneal biomechanical effects after small-incision lenticule extraction and Q value guided femtosecond laser-assisted laser in situ keratomileusis

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2016-04-01

    Full Text Available AIM:By comparing the changes of biomechanical properties of the cornea after small-incision lenticule extraction(SMILEand those after Q value guided femtosecond laser-assisted laser in situ keratomileusis(FSLASIK, to study the stability of biomechanical properties of the cornea after these two kinds of surgery and provide objective data for clinical operation.METHODS: Prospective comparative cases. One hundred and two cases(200 eyeswith myopia and myopic astigmatism were divided into 2 groups, 51 cases(100 eyesfor SMILE, and 51 cases(100 eyesfor Q value guided FS-LASIK. Corneal hysteresis(CHand the corneal resistance factor(CRFwere quantitatively assessed with the Ocular Response Analyzer(ORApreoperatively and 1d, 2wk, 1 and 3mo postoperatively.RESULTS: The decrease in CH and the CRF were statistically significant in both groups(PP>0.05. There were no statistically significant differences between the biomechanical changes in the two groups at any time(P>0.05.CONCLUSION: Both SMILE and Q value guided FS-LASIK can cause biomechanical decreases in the cornea. After 1d postoperatively, the decreases are nearly stable. There are no significant differences between the effect of SMILE and Q value guided FS-LASIK on the biomechanical properties of the cornea.

  15. Monolithic integration of a lithium niobate microresonator with a free-standing waveguide using femtosecond laser assisted ion beam writing

    Science.gov (United States)

    Fang, Zhiwei; Xu, Yingxin; Wang, Min; Qiao, Lingling; Lin, Jintian; Fang, Wei; Cheng, Ya

    2017-01-01

    We demonstrated integrating a high quality factor lithium niobate microdisk resonator with a free-standing membrane waveguide. Our technique is based on femtosecond laser direct writing which produces the pre-structure, followed by focused ion beam milling which reduces the surface roughness of sidewall of the fabricated structure to nanometer scale. Efficient light coupling between the integrated waveguide and microdisk was achieved, and the quality factor of the microresonator was measured as high as 1.67 × 105. PMID:28358135

  16. Comparison of penetrating keratoplasty performed with a femtosecond laser zig-zag incision versus conventional blade trephination.

    Science.gov (United States)

    Farid, Marjan; Steinert, Roger F; Gaster, Ronald N; Chamberlain, Winston; Lin, Amy

    2009-09-01

    To evaluate visual outcomes and astigmatism in patients who underwent penetrating keratoplasty (PK) with 2 different incision techniques. Retrospective comparison of a consecutive surgical series. Fifty-seven consecutive patients who underwent PK at the University of California, Irvine, academic referral practice. A comparison of 49 eyes of 43 patients that underwent femtosecond laser zig-zag incision pattern PK versus 17 eyes of 14 patients that underwent conventional Barron suction trephination PK performed contemporaneously. All PKs were closed with an identical, 24-bite running nylon suture technique. Topographically determined astigmatism, best spectacle-corrected visual acuity (BSCVA), and recovery of full visual potential. The postoperative follow-up ranged from 1 to 12 months. There was a significant difference in average astigmatism between the groups at postoperative month 1 (P = 0.013) and 3 (P = 0.018). By month 3, the average astigmatism was 3 diopters (D) in the zig-zag group and 4.46 D in the conventional group. Of the patients with normal macular and optic nerve function (n(ZZ) = 32; n(con) = 14), a significant difference in BSCVA was seen at month 1 (P = 0.0003) and month 3 (P = 0.006) with 81% of the zig-zag group versus 45% of the conventional group achieving BSCVA of > or =20/40 by month 3 (P = 0.03). The femtosecond laser generated zig-zag-shaped incision results in a more rapid recovery of BSCVA and induces less astigmatism compared with conventional blade trephination PK. Proprietary commercial disclosure may be found after the references.

  17. Rate of ectasia and incidence of irregular topography in patients with unidentified preoperative risk factors undergoing femtosecond laser-assisted LASIK

    Directory of Open Access Journals (Sweden)

    Moshirfar M

    2013-12-01

    Full Text Available Majid Moshirfar,1 Jared G Smedley,2 Valliammai Muthappan,1 Allison Jarsted,3 Erik M Ostler1 1John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA; 2College of Human Medicine, Michigan State University, Lansing, MI, USA; 3Department of Ophthalmology, State University of New York Upstate Medical University, Syracuse, NY, USA Purpose: To report the rate of postoperative ectasia after laser-assisted in situ keratomileusis (LASIK with femtosecond laser-assisted flap creation, in a population of patients with no identified preoperative risk factors. Methods: A retrospective case review of 1,992 eyes (1,364 patients treated between March 2007 and January 2009 was conducted, with a follow up of over 4 years. After identifying cases of ectasia, all the patient charts were examined retrospectively for preoperative findings suggestive of forme fruste keratoconus (FFKC. Results: Five eyes of four patients with post-LASIK ectasia were identified. All eyes passed preoperative screening and received bilateral LASIK. One of the five patients developed ectasia in both eyes. Three patients retrospectively revealed preoperative topography suggestive of FFKC, while one patient had no identifiable preoperative risk factors. Upon review of all the charts, a total 69 eyes, including four of the five eyes with ectasia, were retrospectively found to have topographies suggestive of FFKC. Conclusion: We identified four cases of post-LASIK ectasia that had risk factors for FFKC on reexamination of the chart and one case of post-LASIK ectasia with no identifiable preoperative risk factors. The most conservative screening recommendations would not have precluded this patient from LASIK. The rate of purely iatrogenic post-LASIK ectasia at our center was 0.05% (1/1,992, and the total rate of post-LASIK ectasia for our entire study was 0.25% (1/398. The rate of eyes with unrecognized preoperative FFKC that developed post-LASIK ectasia was 5.8% (1/17. Keywords

  18. Femtosecond laser-assisted in situ keratomileusis multifocal ablation profile using a mini-monovision approach for presbyopic patients with hyperopia

    Directory of Open Access Journals (Sweden)

    Vastardis I

    2016-07-01

    Full Text Available Iraklis Vastardis,1 Brigitte Pajic-Eggspühler,1 Jörg Müller,1,2 Zeljka Cvejic,2 Bojan Pajic,1–4 1Swiss Eye Research Foundation, Orasis Eye Clinic, Aargau, Reinach, Switzerland; 2Faculty of Physics, University of Novi Sad, Novi Sad, Serbia; 3Department of Ophthalmology, Geneva University Hospitals, Geneva, Switzerland; 4Medical Faculty, Military Medical Academy, University of Defence, Belgrade, Serbia Purpose: To report the visual outcomes of the femtosecond laser-assisted multifocal aspheric corneal ablation profile using a mini-monovision approach and to evaluate if corneal multifocality was effective, and to report the relative benefits of this approach.Patients and methods: Bilateral femtosecond laser-assisted in situ keratomileusis using a multifocal aspheric corneal ablation profile was performed on 19 hyperopic patients (38 eyes. They were divided into two groups based on eye dominance: dominant eye (DE group targeting emmetropia and the nondominant eye (NDE group targeting -0.5 D slight myopia. The uncorrected distance visual acuity (UDVA, uncorrected intermediate visual acuity (UIVA, uncorrected near visual acuity (UNVA, and retreatment rates were reported from baseline to 6 months.Results: The UNVA, UIVA, and UDVA improved significantly in both groups (Kruskal–Wallis test, DE and NDE: P<0.00001, P<0.000005, and P=0.00001, respectively. Corrected distance visual acuity (CDVA baseline was better in both groups in comparison to UDVA at 6 months (Wilcoxon test, DE: P<0.001, 95% confidence interval (CI of the median 0.0–0.0 LogMAR and 0.1000–0.1218 LogMAR and NDE: P=0.010, 95% CI of the median 0.0–0.0 LogMAR and 0.00–0.10 LogMAR. There was a significant loss of lines between CDVA baseline and UDVA at 6 months in both groups (DE group: 68% of eyes lost one line or more; NDE group: 58% of eyes lost one line or more. The corrected near visual acuity baseline compared to UNVA at 6 months was not statistically important

  19. Reversible femtosecond laser-assisted myopia correction: a non-human primate study of lenticule re-implantation after refractive lenticule extraction.

    Directory of Open Access Journals (Sweden)

    Andri K Riau

    Full Text Available LASIK (laser-assisted in situ keratomileusis is a common laser refractive procedure for myopia and astigmatism, involving permanent removal of anterior corneal stromal tissue by excimer ablation beneath a hinged flap. Correction of refractive error is achieved by the resulting change in the curvature of the cornea and is limited by central corneal thickness, as a thin residual stromal bed may result in biomechanical instability of the cornea. A recently developed alternative to LASIK called Refractive Lenticule Extraction (ReLEx utilizes solely a femtosecond laser (FSL to incise an intrastromal refractive lenticule (RL, which results in reshaping the corneal curvature and correcting the myopia and/or astigmatism. As the RL is extracted intact in the ReLEx, we hypothesized that it could be cryopreserved and re-implanted at a later date to restore corneal stromal volume, in the event of keratectasia, making ReLEx a potentially reversible procedure, unlike LASIK. In this study, we re-implanted cryopreserved RLs in a non-human primate model of ReLEx. Mild intrastromal haze, noted during the first 2 weeks after re-implantation, subsided after 8 weeks. Refractive parameters including corneal thickness, anterior curvature and refractive error indices were restored to near pre-operative values after the re-implantation. Immunohistochemistry revealed no myofibroblast formation or abnormal collagen type I expression after 8 weeks, and a significant attenuation of fibronectin and tenascin expression from week 8 to 16 after re-implantation. In addition, keratocyte re-population could be found along the implanted RL interfaces. Our findings suggest that RL cryopreservation and re-implantation after ReLEx appears feasible, suggesting the possibility of potential reversibility of the procedure, and possible future uses of RLs in treating other corneal disorders and refractive errors.

  20. Early changes in ocular surface and tear inflammatory mediators after small-incision lenticule extraction and femtosecond laser-assisted laser in situ keratomileusis.

    Directory of Open Access Journals (Sweden)

    Shaohui Gao

    Full Text Available To characterize the early ocular-surface changes or tear inflammatory-mediators levels following small-incision lenticule extraction (ReLEx smile and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK.Forty-seven myopic subjects were recruited for this prospective study. Fifteen underwent ReLEx smile and thirty-two underwent FS-LASIK. Corneal fluorescein (FL staining, tear break-up time (TBUT, Schirmer I test (SIT, ocular surface disease index (OSDI and central corneal sensitivity were evaluated in all participants. Tears were collected and analyzed for interleukin-6 (IL-6, tumor necrosis factor-α (TNF-α, nerve growth factor (NGF and intercellular adhesion molecule-1 (ICAM-1 levels using multiplex magnetic beads. All measurements were preformed preoperatively and 1 day, 1 week, 1 month and 3 months postoperatively.FL scores in ReLEx smile group were lower than those of FS-LASIK group 1 week postoperatively (P = 0.010. Compared to the FS-LASIK group, longer TBUT were observed in ReLEx smile group 1 month (P = 0.029 and 3 months (P = 0.045 postoperatively. No significant differences were found in tear secretion for the two groups (P>0.05. OSDI scores were higher in FS-LASIK group 1 month after surgery (P = 0.020. Higher central corneal sensitivity was observed in ReLEx smile group 1 week, 1 month and 3 months (P0.05. Moreover, IL-6 and NGF levels correlated with ocular surface changes after ReLEx smile or FS-LASIK.In the early postoperative period, ReLEx smile results in milder ocular surface changes than FS-LASIK. Furthermore, the tear inflammatory mediators IL-6 and NGF may play a crucial role in the ocular surface healing process following ReLEx smile and FS-LASIK.

  1. Effect of femtosecond laser-assisted lens surgery on posterior capsule opacification in the human capsular bag in vitro.

    Science.gov (United States)

    Wertheimer, Christian; Kreutzer, Thomas C; Dirisamer, Martin; Eibl-Lindner, Kirsten; Kook, Daniel; Priglinger, Siegfried; Mayer, Wolfgang J

    2017-03-01

    To compare posterior capsule opacification (PCO) by observing lens epithelial cell growth in the human capsular bag in vitro between conventional lens surgery using phacoemulsification (Phaco) technique and femtosecond laser-assisted lens surgery (FLACS). For the in vitro human capsular bag model, 18 cadaver eyes from nine human donors underwent three types of lens surgery. Three groups consisting of six capsular bags were established, that is FLACS, Phaco and extracapsular lens extraction (ECCE). The capsular bag was transferred into equal cell culture conditions after using one of the defined surgical approaches. Cellular growth of lens epithelial cells was observed and photo-documented. The time until full cell-coverage of the capsular bag was measured. The human capsular bag model can be successfully prepared using FLACS. There was no statistically significant difference in time until cell-coverage of the human donor capsular bag in vitro in all three surgical settings (ECCE versus Phaco p = 0.6; ECCE versus FLACS p = 1.0; Phaco versus FLACS p = 1.0). In our in vitro human capsular bag model, we could not observe a statistically significant difference in PCO formation using different surgical approaches of lens extraction. Therefore, PCO formation might not be attributed to the type of surgery. Furthermore, this study shows that FLACS can be used for the human capsular bag model preparation and validates the human capsular bag model for future research. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  2. Topography-guided hyperopic and hyperopic astigmatism femtosecond laser-assisted LASIK: long-term experience with the 400 Hz eye-Q excimer platform

    Directory of Open Access Journals (Sweden)

    Kanellopoulos AJ

    2012-06-01

    Full Text Available Anastasios John KanellopoulosDepartment of Ophthalmology, New York University Medical School, New York, NY, and LaserVision.gr Eye Institute, Athens, GreeceBackground: The purpose of this study was to evaluate the safety and efficacy of topography-guided ablation using the WaveLight 400 Hz excimer laser in laser-assisted in situ keratomileusis (LASIK for hyperopia and/or hyperopic astigmatism.Methods: We prospectively evaluated 208 consecutive LASIK cases for hyperopia with or without astigmatism using the topography-guided platform of the 400 Hz Eye-Q excimer system. The mean preoperative sphere value was +3.04 ± 1.75 (range 0.75–7.25 diopters (D and the mean cylinder value was –1.24 ± 1.41 (–4.75–0 D. Flaps were created either with Intralase FS60 (AMO, Irvine, CA or FS200 (Alcon, Fort Worth, TX femtosecond lasers. Parameters evaluated included age, preoperative and postoperative refractive error, uncorrected distance visual acuity, corrected distance visual acuity, flap diameter and thickness, topographic changes, higher order aberration changes, and low contrast sensitivity. These measurements were repeated postoperatively at regular intervals for at least 24 months.Results: Two hundred and two eyes were available for follow-up at 24 months. Uncorrected distance visual acuity improved from 5.5/10 to 9.2/10. At 24 (8–37 months, 75.5% of the eyes were in the ±0.50 D range and 94.4% were in the ±1.00 D range of the refractive goal. Postoperatively, the mean sphere value was –0.39 ± 0.3 and the cylinder value was –0.35 ± 0.25. Topographic evidence showed that ablation was made in the visual axis and not in the center of the cornea, thus correlating with the angle kappa. No significant complications were encountered in this small group of patients.Conclusion: Hyperopic LASIK utilizing the topography-guided platform of the 400 Hz Eye-Q Allegretto excimer and a femtosecond laser flap appears to be safe and effective for

  3. 飞秒激光辅助白内障摘除手术的临床分析%Clinic analysis of femtosecond laser-assisted cataract surgery

    Institute of Scientific and Technical Information of China (English)

    张广斌; 叶向彧; 陈伟; 毛祖红; 王乐; 李孟琼

    2016-01-01

    目的 评估飞秒激光辅助超声乳化白内障吸除手术的安全性及有效性.方法 病例对照研究.2013年4月至11月在厦门眼科中心行超声乳化白内障手术的患者233例(314只眼),将其分为飞秒激光组(153只眼)及传统超声乳化组(161只眼),比较两组术前一般情况,术中超声乳化能量释放量(CDE)、有效超声时间(EPT)、角膜内皮丢失量、房水闪光值及术后并发症.计量资料采用独立样本t检验;计数资料采用交互列表的卡方或者Fisher确切概率法分析.结果 两组术前一般情况(年龄、性别、眼压、眼轴、角膜曲率、前房深度、核分级)差异无统计学意义(P>0.05).飞秒激光组CDE、EPT分别为4.78%(3.18%~8.88%)和14.05 s(10.07 ~ 20.85 s),小于传统超声乳化组的8.82%(6.01%~19.16%)和23.65 s(18.36 ~ 46.96 s),差异有统计学意义(z=2.30,2.91;P<0.05).飞秒激光组撕囊相对直径和圆形度均较传统超声乳化组更精确(t=2.58,3.92;P<0.05).角膜内皮丢失量在术后1个月时飞秒激光组为73.50(-69.51~ 111.03)个/mm2,低于传统超声乳化组的118.06(53.55~299.03)个/mm2,差异有统计学意义(z=2.44;P<0.05).房水闪光值在术后1d激光组18.81(13.32~20.23) ph/ms,传统超声乳化组24.51(16.38~ 32.18) ph/m和1个月时飞秒激光组13.01(9.23~ 16.28) ph/ms,传统超声乳化组18.05(12.37~ 24.97) ph/ms,传统超声乳化组均高于飞秒激光组,差异有统计学意义(z=2.40,2.31;P<0.05).两组术后均无严重并发症出现.结论 飞秒激光辅助超声乳化白内障吸除手术具有较高安全性及有效性,可降低CDE和减少EPT,进而减少角膜内皮损伤和术后前房反应,且撕囊更精确、重复性更好.%Objective To evaluate the safety and effectiveness of femtosecond laser-assisted cataract surgery.Methods The interventional case series enrolled 314 eyes undergoing cataract surgery in Xiamen Ophthalmic Center between April and

  4. Small Incision Lenticule Extraction (SMILE versus Femtosecond Laser-Assisted In Situ Keratomileusis (FS-LASIK for Myopia: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Zeren Shen

    Full Text Available The goal of this study was to compare small incision lenticule extraction (SMILE with femtosecond laser-assisted in situ keratomileusis (FS-LASIK for treating myopia.The CENTRAL, EMBASE, PubMed databases and a Chinese database (SinoMed were searched in May of 2016. Twelve studies with 1,076 eyes, which included three randomized controlled trials (RCTs and nine cohorts, met our inclusion criteria. The overall quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE working group framework. Data were extracted and analysed at three to six months postoperatively. Primary outcome measures included a loss of one or more lines of best spectacle corrected visual acuity (BSCVA, uncorrected visual acuity (UCVA of 20/20 or better, mean logMAR UCVA, postoperative mean spherical equivalent (SE and postoperative refraction within ±1.0 D of the target refraction. Secondary outcome measures included ocular surface disease index (OSDI, tear breakup time (TBUT and Schirmer's 1 test (S1T as dry eye parameters, along with corneal sensitivity.The overall quality of evidence was considered to be low to very low. Pooled results revealed no significant differences between the two groups with regard to a loss of one or more lines in the BSCVA (OR 1.71; 95% CI: 0.81, 3.63; P = 0.16, UCVA of 20/20 or better (OR 0.71; 95% CI: 0.44, 1.15; P = 0.16, logMAR UCVA (MD 0.00; 95% CI: -0.03, 0.04; P = 0.87, postoperative refractive SE (MD -0.00; 95% CI: -0.05, 0.05; P = 0.97 or postoperative refraction within ±1.0 D of the target refraction (OR 0.78; 95% CI: 0.22, 2.77; P = 0.70 within six months postoperatively. The pooled analysis also indicated that the FS-LASIK group suffered more severely from dry eye symptoms (OSDI; MD -6.68; 95% CI: -11.76, -2.00; P = 0.006 and lower corneal sensitivity (MD 12.40; 95% CI: 10.23, 14.56; P < 0.00001 at six months postoperatively.In conclusion, both FS-LASIK and SMILE are safe

  5. Laser assisted robotic surgery in cornea transplantation

    Science.gov (United States)

    Rossi, Francesca; Micheletti, Filippo; Magni, Giada; Pini, Roberto; Menabuoni, Luca; Leoni, Fabio; Magnani, Bernardo

    2017-03-01

    Robotic surgery is a reality in several surgical fields, such as in gastrointestinal surgery. In ophthalmic surgery the required high spatial precision is limiting the application of robotic system, and even if several attempts have been designed in the last 10 years, only some application in retinal surgery were tested in animal models. The combination of photonics and robotics can really open new frontiers in minimally invasive surgery, improving the precision, reducing tremor, amplifying scale of motion, and automating the procedure. In this manuscript we present the preliminary results in developing a vision guided robotic platform for laser-assisted anterior eye surgery. The robotic console is composed by a robotic arm equipped with an "end effector" designed to deliver laser light to the anterior corneal surface. The main intended application is for laser welding of corneal tissue in laser assisted penetrating keratoplasty and endothelial keratoplasty. The console is equipped with an integrated vision system. The experiment originates from a clear medical demand in order to improve the efficacy of different surgical procedures: when the prototype will be optimized, other surgical areas will be included in its application, such as neurosurgery, urology and spinal surgery.

  6. In vivo ultrathin Descemet stripping automated endothelial keratoplasty with a low-energy and high-frequency femtosecond laser

    Directory of Open Access Journals (Sweden)

    Gustavo Victor

    2014-04-01

    Full Text Available This case report describes the production of an ultrathin endothelial donor corneal lamella using a femtosecond laser with low energy and a high frequency. In addition, we report its use in vivo in an eye with pseudophakic bullous keratopathy. The outcomes were observed 3 months after surgery in terms of the change in endothelial donor lamella and full cornea thickness (including pachymetric mapping, visual acuity, and endothelial cell count.

  7. Femtosecond laser's application in the corneal surgery

    Directory of Open Access Journals (Sweden)

    Shu-Liang Wang

    2015-10-01

    Full Text Available With the rapid development over the past two decades,femtosecond(10-15slasers(FShas become a new application in ophthalmic surgery. As laser power is defined as energy delivered per unit time, decreasing the pulse duration to femtosecond level(100fsnot only increases the power delivered but also decreases the fluence threshold for laser induced optical breakdown. In ablating tissue, FS has an edge over nanosecond lasers as there is minimal collateral damage from shock waves and heat conduction during surgical ablation. Thus, application of FS has been widely spread, from flap creation for laser-assisted in situ keratomileusis(LASIKsurgery, cutting of donor and recipient corneas in keratoplasty, creation of pockets for intracorneal ring implantation. FS applied in keratoplasty is mainly used in making graft and recipient bed, and can exactly cut different tissue of keratopathy. FS can also cut partial tissue of cornea, even if it is under the moderate corneal macula and corneal edema condition.

  8. Can we improve the efficacy of modern cataract surgery by using different tip designs? A comparison of balanced and tapered tip in femtosecond laser-assisted cataract surgery and manual phacoemulsification.

    Science.gov (United States)

    Pahlitzsch, Milena; Pahlitzsch, Marie-Luise; Sumarni, Uly; Pahlitzsch, Thomas

    2017-05-31

    Different tip designs in modern cataract surgery have not been studied between the reported systems. Aim of this study is to assess the efficacy of two tip designs, Intrepid® balanced tip (BT) and Kelman tapered tip (TT), in femtosecond laser assisted cataract surgery (FLACS) and the microcoaxial torsional phacoemulsification. Prospective randomized unmasked cohort outcome study (hospital setting). Threehundert-forty-three eyes of 343 patientes underwent cataract surgery. Data of n = 196 FLACS and n = 147 manual phacoemulsification were analysed. Intrepid® balanced tip and Kelman tapered tip, Alcon, USA, were tested in FLACS (LenSx Alcon, USA) und manual phaco (Alcon Centurion System, USA). Four study cohorts were formed; FLACS BT (n = 90, 70.2 years), FLACS TT (n = 106, 68.1years), Manual BT (n = 70, 71.3 years), Manual TT (n = 77, 71.8 years). The nuclei were graded in Lens Opacities Classification System (LOCS) II,III and IV. Cumulative dissipated energy (CDE%s), balanced salt solution volume (BSSml), total longitudinal energy (%s) and torsional amplitude (%s). Lower CDE values were seen in FLACS compared to manual phacoemulsification (CDE %s median FLACS BT 3.28, FLACS TT 4.07, Manual BT 5.57, Manual TT 6.27). There was a significant difference between CDE FLACS BT and FLACS TT (p = 0.038), and between FLACS BT and Manual TT (p = 0.001). The right choice of tip designs in advanced phacoemulsification systems is a key factor in increasing efficacy in cataract surgery. The balanced tip showed a considerable energy-saving advantage in FLACS and manual phacoemulsification compared to the tapered tip. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

  9. Laser-assisted photoelectric effect from surfaces.

    Science.gov (United States)

    Miaja-Avila, L; Lei, C; Aeschlimann, M; Gland, J L; Murnane, M M; Kapteyn, H C; Saathoff, G

    2006-09-15

    We report the first observation of the laser-assisted photoelectric effect from a solid surface. By illuminating a Pt(111) sample simultaneously with ultrashort 1.6 eV and 42 eV pulses, we observe sidebands in the extreme ultraviolet photoemission spectrum. The magnitude of these sidebands as a function of time delay between the laser and extreme ultraviolet pulses represents a cross-correlation measurement of the extreme ultraviolet pulse. This effect promises to be useful to extend extreme ultraviolet pulse duration measurements to higher photon energies, as well as opening up femtosecond-to-attosecond time-scale electron dynamics in solid and surface-adsorbate systems.

  10. Laser assisted electron dynamics

    CERN Document Server

    Bray, Alexander William

    2016-01-01

    We apply the convergent close-coupling (CCC) formalism to analyse the processes of laser assisted electron impact ionisation of He, and the attosecond time delay in the photodetachment of the H^{-} ion and the photoionisation of He. Such time dependent atomic collision processes are of considerable interest as experimental measurements on the relevant timescale (attoseconds 10^{-18} s) are now possible utilising ultrafast and intense laser pulses. These processes in particular are furthermore of interest as they are strongly influenced by many-electron correlations. In such cases their theoretical description requires a more comprehensive treatment than that offered by first order perturbation theory. We apply such a treatment through the use of the CCC formalism which involves the complete numeric solution of the integral Lippmann-Schwinger equations pertaining to a particular scattering event. For laser assisted electron impact ionisation of He such a treatment is of a considerably greater accuracy than the...

  11. Manual suction versus femtosecond laser trephination for penetrating keratoplasty: intraocular pressure, endothelial cell damage, incision geometry, and wound healing responses.

    Science.gov (United States)

    Angunawela, Romesh I; Riau, Andri; Chaurasia, Shyam S; Tan, Donald T; Mehta, Jodhbir S

    2012-05-04

    To measure real-time intraocular pressure (IOP) during trephination with a manual suction trephine (MST) and the femtosecond laser (FSL), and to assess endothelial cell damage, incision geometry, and wound healing response with these procedures. IOP was monitored with an intracameral sensor. Eight rabbits underwent manual suction trephination. Eight rabbits had FSL trephination (FSL-T). Slit lamp photography, confocal microscopy, and anterior segment optical coherence tomography (AS-OCT) were performed at baseline and postoperatively. Animals were sacrificed at 4 hours and 3 days. Tissue was examined with scanning electron microscopy (SEM) and immunohistochemistry for an array of wound-healing markers. Separately, 6 human corneas had MST (3) and FSL-T (3). Incision geometry was imaged with high resolution Optovue AS-OCT. The average IOP during MST and FSL-T was similar (37 mm Hg). There was wider IOP fluctuation during the MST cutting phase (60 mm Hg maximum). There were 1-2 rows of endothelial loss on either side of the incision for FSL-T and 2-5 rows deep for MST. Immune cell responses at 4 hours (CD11b) were comparable, greater apoptosis with FSL-T (TUNEL) occurred at 4 hours, and there was increased keratocyte proliferation at 3 days (Ki67) with FSL-T. There was significantly greater undercutting of the cornea with MST (46.86 degrees versus 16.72 degrees). There is more IOP variation during MST. Average IOP is 37 mm Hg for both techniques. More endothelial damage and undercutting of the cornea occurs with MST. The wound healing response to FSL-T appears greater at 3 days.

  12. Femtosecond-assisted preparation of donor tissue for Boston type 1 keratoprosthesis

    Directory of Open Access Journals (Sweden)

    Moshirfar M

    2011-07-01

    Full Text Available Majid Moshirfar1, Marcus C Neuffer1, Krista Kinard1, Monette T Lependu1, Shameema Sikder21John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USAAbstract: We describe a technique for femtosecond laser-assisted preparation of donor tissue for Boston type 1 keratoprosthesis to provide accurate double punching of the donor tissue for optimized alignment in the visual axis. The technique was reproducibly performed in four donor corneas mounted in an artificial anterior chamber. This technique can provide optically centered donor tissue with smooth trephinated edges.Keywords: keratoplasty, femtosecond laser, cornea, laser-trephinated tissue

  13. Laser assisted forming techniques

    Science.gov (United States)

    Kratky, Alexander

    2007-05-01

    During forming processes high deformations rates can lead to cracks and rupture very easily. Especially brittle materials like titanium or magnesium make difficulties in forming. Due to the dependence of the yield strength on temperature, forming at elevated temperatures eases processing of such materials. Since forming takes place only at localized areas of the work piece selective heating is suffcient and advantageous in most cases. Selective Laser heating offers a possibility to heat only the areas of the work piece where strongest deformations are required. For this purpose several laser sources have been tested like CO II, Diode and Nd:YAG Lasers and their advantages and disadvantages in localized heating of the work pieces will be discussed. The work presented here summarizes research activities at the Institute for Forming and High Power Laser Technology, Vienna University of Technology, on laser assisted deep drawing, laser assisted bending, wire drawing and so on during the last decade. Recent developments like roll profiling, incremental forming processes and hydro forming are discussed briefly.

  14. Laser assisted {alpha} decay

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda Cortes, Hector Mauricio

    2012-02-01

    Excited or short-lived nuclei often decay by emitting alpha particles that are assumed to be preformed inside the nucleus and confined in the nuclear potential well. In this picture, {alpha} decay refers to the tunneling of the alpha particle through the potential barrier. In this thesis we investigate for the first time how strong laser fields can assist the tunneling of the alpha particle and thus influence the nuclear decay. Generally speaking, laser-assisted {alpha} decay can be described as laser-assisted tunneling of a quasistationary state, i.e, a slowly decaying state. Our theoretical treatment is developed starting from the complex trajectory formulation of the well-known strong-field approximation used to describe laser-induced ionization. We extend this formulation and develop a method to treat the decay of quasistationary states. The effect of both static and optical and X-ray monochromatic fields on the lifetimes and {alpha}-particle emission spectra are investigated for a number of {alpha}-emitting nuclei. We find that even at strong intensities, the laser-induced acceleration of the {alpha} decay is negligible, ranging from a relative modification in the decay rate of 10{sup -3} for static fields of electric field strengths of 10{sup 15} V/m, to 10{sup -8} for strong optical fields with intensities of 10{sup 22} W/cm{sup 2}, and to 10{sup -6} for strong X-ray fields with laser intensities around 10{sup 24} W/cm{sup 2}. However, the effect of the external field is visible in the spectrum of emitted alpha particles, leading in the case of optical fields even to rescattering phenomena for intensities approaching 6 x 10{sup 22} W/cm{sup 2}. The dynamics of the alpha particle in laser fields of intensities below the rescattering limit is investigated.

  15. Laser assisted graffiti paints removing

    Science.gov (United States)

    Novikov, B. Y.; Chikalev, Y. V.; Shakhno, E. A.

    2011-02-01

    It's hard to imagine a modern city view without some drawings and inscriptions, usually called "graffiti". Traditional cleaning methods do not suit modern requirements. Investigation of possibilities of laser assisted paints removing is described in this article. The conditions for removing different paints from different surfaces were defined.

  16. Laser assisted hair-removal.

    Science.gov (United States)

    Choudhary, S; Elsaie, M L; Nouri, K

    2009-10-01

    A number of lasers and light devices are now available for the treatment of unwanted hair. The goal of laser hair removal is to damage stem cells in the bulge of the hair follicle by targeting melanin, the endogenous chromophore for laser and light devices utilized to remove hair. The competing chromophores in the skin and hair, oxyhemoglobin and water, have a decreased absorption between 690 nm and 1000 nm, thus making this an ideal range for laser and light sources. Laser hair removal is achieved through follicular unit destruction based on selective photothermolysis. The principle of selective photothermolysis predicts that the thermal injury will be restricted to a given target if there is sufficient selective absorption of light and the pulse duration is shorter than the thermal relaxation time of the target. This review will focus on the mechanisms of laser assisted hair removal and provide an update on the newer technologies emerging in the field of lasers assisted hair removal.

  17. Rhabdomyolysis After Cosmetic Laser-Assisted Liposuction.

    Science.gov (United States)

    Shin, Jin-yong; Chang, Hak

    2015-08-01

    A 34-year-old-female patient visited our emergency room for symptoms of disturbance of urination and shortness of breath. She was diagnosed with rhabdomyolysis with acute kidney injury after laser-assisted liposuction and required hemodialysis. Although laser-assisted liposuction is a well-used procedure, it can cause local complications, such as burns and skin irregularities, as well as systemic complications, such as infection, fever, and emboli. However, laser-assisted, liposuction-induced rhabdomyolysis has not been reported. Repetitive exercises, trauma, and crush injury are the major causes of rhabdomyolysis. In this study, a unique case of rhabdomyolysis that developed after laser-assisted liposuction is reported.

  18. Laser-assisted fabrication of materials

    CERN Document Server

    Manna, Indranil

    2013-01-01

    Laser assisted fabrication involves shaping of materials using laser as a source of heat. It can be achieved by removal of materials (laser assisted cutting, drilling, etc.), deformation (bending, extrusion), joining (welding, soldering) and addition of materials (surface cladding or direct laser cladding). This book on ´Laser assisted Fabrication’ is aimed at developing in-depth engineering concepts on various laser assisted macro and micro-fabrication techniques with the focus on application and a review of the engineering background of different micro/macro-fabrication techniques, thermal history of the treated zone and microstructural development and evolution of properties of the treated zone.

  19. Financial modelling of femtosecond laser-assisted cataract surgery within the National Health Service using a ‘hub and spoke’ model for the delivery of high-volume cataract surgery

    Science.gov (United States)

    Roberts, H W; Ni, M Z; O'Brart, D P S

    2017-01-01

    Aims To develop financial models which offset additional costs associated with femtosecond laser (FL)-assisted cataract surgery (FLACS) against improvements in productivity and to determine important factors relating to its implementation into the National Health Service (NHS). Methods FL platforms are expensive, in initial purchase and running costs. The additional costs associated with FL technology might be offset by an increase in surgical efficiency. Using a ‘hub and spoke’ model to provide high-volume cataract surgery, we designed a financial model, comparing FLACS against conventional phacoemulsification surgery (CPS). The model was populated with averaged financial data from 4 NHS foundation trusts and 4 commercial organisations manufacturing FL platforms. We tested our model with sensitivity and threshold analyses to allow for variations or uncertainties. Results The averaged weekly workload for cataract surgery using our hub and spoke model required either 8 or 5.4 theatre sessions with CPS or FLACS, respectively. Despite reduced theatre utilisation, CPS (average £433/case) was still found to be 8.7% cheaper than FLACS (average £502/case). The greatest associated cost of FLACS was the patient interface (PI) (average £135/case). Sensitivity analyses demonstrated that FLACS could be less expensive than CPS, but only if increased efficiency, in terms of cataract procedures per theatre list, increased by over 100%, or if the cost of the PI was reduced by almost 70%. Conclusions The financial viability of FLACS within the NHS is currently precluded by the cost of the PI and the lack of knowledge regarding any gains in operational efficiency. PMID:28302635

  20. Investigation of surgically induced astigmatism resulting from femtosecond laser-assisted cataract surgery using a 2.2 mm clear corneal incision%2.2mm透明角膜切口飞秒激光辅助白内障超声乳化手术术源性散光的临床研究

    Institute of Scientific and Technical Information of China (English)

    李博; 张素华; 张哲; 刘建亭; 曹伟芳; 李晓艳; 董慧; 郭彩虹; 张海宁

    2016-01-01

    Objective To evaluate surgically induced astigmatism (SIA) resulting from femtosecond laser-assisted phacoemulsification cataract surgery with a 2.2 mm clear corneal incision.Methods A prospective,comparative analysis was performed in a case series.A total of 105 eyes of 84 patients (from No.1 cataract department of Shanxi Eye Hospital) who underwent femtosecond laser-assisted phacoemulsification cataract surgery between March 2014 and April 2016 were enrolled in this study.The main outcomes were a comparison of SIA,far visual acuity,and spherical refractive power preoperatively and 1,3,and 6 months postoperatively.Distance visual acuity was recorded as logMAR.Based on follow-up times (1,3,and 6 months postoperatively),lens nucleus hardness (grades Ⅱ,Ⅲ,Ⅳ),corneal astigmatism types (with-the-rule,against-the-rule,oblique) and laterality (left,right),SIA was analyzed using Alphins vector analysis.Data were analyzed using repeated measured ANOVA.Results The mean preoperative logMAR visual acuity was 0.65±0.24,which was significantly different from postoperative logMAR visual acuity at 1 month (0.07±0.02),3 months (0.06±0.01),and 6 months (0.06±0.01).No significant logMAR visual acuity differences were found at the three postoperative follow-up times.SIAs at 1,3,and 6 months after surgery were 0.28±0.11 D,0.25±0.13 D,0.24±0.10 D,respectively.No statistically significant differences in SIA were found when postoperative follow-up times (1,3,and 6 months) and factor groups for lens nucleus hardness (grades Ⅱ,Ⅲ,Ⅳ),corneal astigmatism types (with-the-rule,against-the-rule,oblique) and laterality (left,right) were compared.Conclusion Femtosecond laser-assisted phacoemulsification cataract surgery using a 2.2 mm clear corneal incision can provide stable SIA and better postoperative visual acuity.%目的 观察飞秒激光辅助白内障超声乳化手术中2.2 mm透明角膜切口引起的术源性散光(SIA)的影响因素.方法 前瞻性研究.纳入2014

  1. Laser welding in penetrating keratoplasty and cataract surgery in pediatric patients: early results.

    Science.gov (United States)

    Buzzonetti, Luca; Capozzi, Paolo; Petrocelli, Gianni; Valente, Paola; Petroni, Sergio; Menabuoni, Luca; Rossi, Francesca; Pini, Roberto

    2013-12-01

    To evaluate the efficacy of diode laser welding to close corneal wounds in penetrating keratoplasty (PKP) and cataract surgery in pediatric patients. Ophthalmology Department, Bambino Gesù Children's Hospital, Rome, Italy. Prospective observational study. Patients had surgery for congenital cataract (Group 1) or femtosecond laser-assisted PKP (Group 2). The surgery was followed by corneal wound closure using diode laser welding of the stroma. In Group 1, no standard suturing was used. In Group 2, the donor button was sutured onto the recipient using 8 single nylon sutures or a 10-0 nylon running suture (12 passages). Laser welding was then used as an adjunct to the traditional suturing procedure. Group 1 comprised 7 eyes (7 patients; mean age 8.1 years ± 5.3 [SD], range 1 to 15 years) and Group 2, 5 eyes (5 patients; mean age 10.6 ± 3.3 years, range 6 to 15 years). The adhesion of the laser-welded tissues was perfect; there were no collateral effects, and restoration of the treated tissues was optimum. Seidel testing showed no wound leakage during the follow-up. Postoperative astigmatism did not change significantly from the first day after cataract surgery and shifted moderately 3 months after PKP. Laser welding of corneal tissue appeared to be safe and effective in children for whom a sutureless surgical procedure is important to reduce the use of anesthesia for suture management, prevent endophthalmitis, and improve the antiamblyopic effect. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  2. Commissioning of laser assisted cold spraying technology

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2012-10-01

    Full Text Available This study demonstrates the potential of a newly designed, assembled and commissioned laser assisted cold spraying (LACS) technology at the National Laser Centre, Pretoria, South Africa, to deposit Al-12wt%Si coatings on stainless steel substrate...

  3. Ballistic laser-assisted solid transfer (BLAST) from a thin film precursor.

    Science.gov (United States)

    Banks, David P; Grivas, Christos; Zergioti, Ioanna; Eason, Robert W

    2008-03-03

    A novel technique for the laser-induced forward transfer (LIFT) of material in solid phase from a thin film precursor is presented. Multiple, sub-threshold energy femtosecond pulses are used to lessen the adhesion of a donor film to a support substrate to facilitate forward transfer of solid 'pellets' of donor material to a receiver. A relatively higher intensity outer ring is added to the transfer laser pulses, by means of the near-field diffraction pattern of a circular aperture, to define the area for transfer in the donor film and allow for more reproducible pellet shapes. This technique has been termed Ballistic Laser-Assisted Solid Transfer (BLAST).

  4. Multi-scale graphene patterns on arbitrary substrates via laser-assisted transfer-printing process

    KAUST Repository

    Park, J. B.

    2012-01-01

    A laser-assisted transfer-printing process is developed for multi-scale graphene patterns on arbitrary substrates using femtosecond laser scanning on a graphene/metal substrate and transfer techniques without using multi-step patterning processes. The short pulse nature of a femtosecond laser on a graphene/copper sheet enables fabrication of high-resolution graphene patterns. Thanks to the scale up, fast, direct writing, multi-scale with high resolution, and reliable process characteristics, it can be an alternative pathway to the multi-step photolithography methods for printing arbitrary graphene patterns on desired substrates. We also demonstrate transparent strain devices without expensive photomasks and multi-step patterning process. © 2012 American Institute of Physics.

  5. Endothelial keratoplasty: evolution and horizons

    Directory of Open Access Journals (Sweden)

    Gustavo Teixeira Grottone

    2012-12-01

    Full Text Available Endothelial keratoplasty has been adopted by corneal surgeons worldwide as an alternative to penetrating keratoplasty (PK in the treatment of corneal endothelial disorders. Since the first surgeries in 1998, different surgical techniques have been used to replace the diseased endothelium. Compared with penetrating keratoplasty, all these techniques may provide faster and better visual rehabilitation with minimal change in refractive power of the transplanted cornea, minimal induced astigmatism, elimination of suture-induced complications and late wound dehiscence, and a reduced demand for postoperative care. Translational research involving cell-based therapy is the next step in work on endothelial keratoplasty. The present review updates information on comparisons among different techniques and predicts the direction of future treatment.

  6. Quantum Electrodynamics Theory of Laser Assisted Recombination

    Institute of Scientific and Technical Information of China (English)

    敖淑艳; 程太旺; 李晓峰; 潘守甫; 傅盘铭

    2003-01-01

    Using a formal scattering theoretical approach, we develop a nonperturbative quantum electrodynamics theory to describe laser assisted recombination (LAR), in which an electron initially in the quantized Volkov state recombines with an ion and emits a high-energy photon with frequency defined by energy conservation laws.The transition probability is expressed as an analytic closed form and the spectrum of LAR reflects mainly the properties of general Bessel functions. For the case of a fast electron the LAR spectrum is confined in a well-defined range, while for a slow electron, the LAR spectrum exhibits a double-plateau structure.

  7. Laser assisted Drug Delivery: Grundlagen und Praxis.

    Science.gov (United States)

    Braun, Stephan Alexander; Schrumpf, Holger; Buhren, Bettina Alexandra; Homey, Bernhard; Gerber, Peter Arne

    2016-05-01

    Die topische Applikation von Wirkstoffen ist eine zentrale Therapieoption der Dermatologie. Allerdings mindert die effektive Barrierefunktion der Haut die Bioverfügbarkeit der meisten Externa. Fraktionierte ablative Laser stellen ein innovatives Verfahren dar, um die epidermale Barriere standardisiert, kontaktfrei zu überwinden. Die Bioverfügbarkeit im Anschluss applizierter Externa wird im Sinne einer laser assisted drug delivery (LADD) signifikant gesteigert. Das Prinzip der LADD wird bereits in einigen Bereichen der Dermatologie erfolgreich eingesetzt. Die vorliegende Übersichtsarbeit soll einen Überblick über die aktuellen aber auch perspektivischen Einsatzmöglichkeiten der LADD bieten.

  8. Laser-assisted growth of carbon nanotubes - A review

    NARCIS (Netherlands)

    Burgt, Y. van de

    2014-01-01

    Laser-assisted chemical vapor deposition (LACVD) is an attractive maskless process for growing locally carbon nanotubes at selected places on substrates that may contain temperature-sensitive components. This review gives a comprehensive overview of the reported research with respect to laser assist

  9. Laser-Assisted Photoelectric Effect from Liquids

    Science.gov (United States)

    Arrell, C. A.; Ojeda, J.; Mewes, L.; Grilj, J.; Frassetto, F.; Poletto, L.; van Mourik, F.; Chergui, M.

    2016-09-01

    The laser-assisted photoelectric effect from liquid surfaces is reported for the first time. Photoelectrons generated by 35.6 eV radiation from a liquid microjet of water under vacuum are dressed with a ℏω =1.55 eV laser field. The subsequent redistribution of the photoelectron energies consists in the appearance of sidebands shifted by energies equivalent to ℏω , 2 ℏω , and 3 ℏω . The response has been modeled to the third order and combined with energy-resolved measurements. This result opens the possibility to investigate the dynamics at surfaces of liquid solutions and provide information about the electron emission process from a liquid.

  10. The Laser-assisted photoelectric effect of He, Ne, Ar and Xe in intense extreme ultraviolet and infrared laser fields

    Science.gov (United States)

    Hayden, P.; Dardis, J.; Hough, P.; Richardson, V.; Kennedy, E. T.; Costello, J. T.; Düsterer, S.; Redlin, H.; Feldhaus, J.; Li, W. B.; Cubaynes, D.; Meyer, M.

    2016-02-01

    In this paper, we report results on two-colour above-threshold ionisation, where extreme ultraviolet pulses of femtosecond duration were synchronised to intense infrared laser pulses of picosecond duration, in order to study the laser-assisted photoelectric effect of atomic helium, neon, krypton and xenon which leads to the appearance of characteristic sidebands in the photoelectron spectra. The observed trends are found to be well described by a simple model based on the soft-photon approximation, at least for the relatively low optical intensities of up to ? employed in these early experiments.

  11. Laser-assisted rapid prototyping in Japan

    Science.gov (United States)

    Kathuria, Yash P.

    2002-04-01

    In the recent past years, developments in the rapid prototyping of various parts have taken new dynamic turns in manufacturing technology. Besides the use of new materials, unrelenting demands for the downsizing of miniature components in the micro-domain have expanded the application area of the rapid prototype product. Their requirements with reduced time lag have forced the manufacturers to adopt and develop innovative techniques which meet these demands. In order to overcome this problem, several techniques, predominantly laser stereolithography, have successfully been used in Japan for the past several years to generate a complex micro-/macro part of polymer resin based in two- or three-dimensional domains. The main disadvantage of this process is that they consist of two or more steps for producing metallic/metal-matrix composite microstructures. But recently developed new technologies of selective laser sintering/generating and ballistic particles manufacturing processes offer the possibility of the direct generation of these microstructures in a single step process. The last two processes actually have limitations on the feature size produced, due to the minimum size of the molten droplet. But the selective laser sintering technique can bind the particles by melting together at the interfacial grain contact area only and thus producing smaller feature sizes. Based upon these techniques, the present paper aims to review the current status and the future prospective of laser assisted rapid prototyping in Japan.

  12. Cell patterning by laser-assisted bioprinting.

    Science.gov (United States)

    Devillard, Raphaël; Pagès, Emeline; Correa, Manuela Medina; Kériquel, Virginie; Rémy, Murielle; Kalisky, Jérôme; Ali, Muhammad; Guillotin, Bertrand; Guillemot, Fabien

    2014-01-01

    The aim of tissue engineering is to produce functional three-dimensional (3D) tissue substitutes. Regarding native organ and tissue complexity, cell density and cell spatial 3D organization, which influence cell behavior and fate, are key parameters in tissue engineering. Laser-Assisted Bioprinting (LAB) allows one to print cells and liquid materials with a cell- or picoliter-level resolution. Thus, LAB seems to be an emerging and promising technology to fabricate tissue-like structures that have the physiological functionality of their native counterparts. This technology has additional advantages such as automation, reproducibility, and high throughput. It makes LAB compatible with the (industrial) fabrication of 3D constructs of physiologically relevant sizes. Here we present exhaustively the numerous steps that allow printing of viable cells with a well-preserved micrometer pattern. To facilitate the understanding of the whole cell patterning experiment using LAB, it is discussed in two parts: (1) preprocessing: laser set-up, bio-ink cartridge and bio-paper preparation, and pattern design; and (2) processing: bio-ink printing on the bio-paper.

  13. Laser-assisted hatching in assisted reproduction.

    Science.gov (United States)

    Montag, M; van der Ven, H

    1999-09-01

    The use of a 1.48 um diode laser for assisted hatching was investigated in animal experimentation. Laser assisted hatching was offered to patients with advanced maternal age to evaluate a possible benefit. Using the Fertilase(r) system we investigated the impact of openings with different size in the zona of mouse embryos on the hatching process, as well as that of two openings. Laser-drilling was performed at the blastocyst stage to look for differences in timing and efficacy of hatching. The possible benefit of assisted hatching was studied in 24 couples with advanced maternal age (38.8+2.1 years) and compared to a control group (37.8+2.5 years) treated in the same time period but without assisted hatching. A certain diameter of a laser drilled opening in the zona pellucida is necessary for efficient hatching. When two openings are present in the zona, the embryo will use both openings for hatching and subsequently become trapped. Laser-drilling at th e expanded blastocyst stage causes an immediate collapse of treated blastocysts and the onset of hatching is retarded. Assisted hatching in 24 patients with advanced maternal age resulted in a significant increase (plaser to drill an opening into the zona pellucida provides a good alternate to conventionally applied techniques. The procedure is efficient and safe as long as it is applied properly. In a human in vitro fertilization program, selected patients will have a benefit form assisted hatching.

  14. Refractive keratoplasty. Keratophakia and keratomileusis.

    Science.gov (United States)

    Troutman, R C; Swinger, C

    1982-01-01

    Early experience with the refractive keratoplasty techniques of José Barraquer--keratophakia and hypermetropic keratomileusis is presented. In contradistinction to the alloplastic lens substitutes currently being employed for the integral correction of aphakia, Barraquer's techniques would seem to offer a more permanent, more physiologic, full-time optical correction of the aphakic state. Their use is limited only by the condition of the patient's cornea and, in fact, may be applied not only in aphakia but also in phakic eyes with higher degrees of hyperopia or myopia. In the opinion of the authors, the refractive keratoplasty techniques of Barraquer can be performed by any well-instructed ophthalmic surgeon. These techniques offer to many patients a satisfactory, and potentially a physiologically superior alternative to alloplastic lens substitute for aphakic correction.

  15. Refractive keratoplasty: keratophakia and keratomileusis.

    Science.gov (United States)

    Troutman, R C; Swinger, C

    1978-01-01

    We have presented our early experience with the refractive keratoplasty techniques of Doctor Jose Barraquer--keratophakia and hypermetropic keratomileusis. In contradistinction to the alloplastic lens substitutes currently being employed for the integral correction of aphakia, his techniques would seem to offer a more permanent, more physiologic, full-time optical correction of the aphakic state. Their use is limited only by the condition of the patient's corneaa and, in fact, may be applied not only in aphakia but also in phakic eyes with higher degrees of hyperopia or myopia. In the opinion of the authors, the refractive keratoplasty techniques of Barraquer can be perfored by any well-instructed ophthalmic surgeon. These techniques offer to many patients a satisfactory and potentially a physiologically superior alternative to alloplastic lens substitute for aphakic correction.

  16. Graft stability after endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Jovanović Vesna

    2015-01-01

    Full Text Available Bacground/Aim. Techniques for replacing the corneal endothelium have been improved. The host-graft interface is the key to graft adhesion and visual recovery. The aim of this study was to establish graft stability after Descemet stripping with endothelial keratoplasty (DSEK, compare it to the graft stability after endothelial keratoplasty with the intact posterior corneal layers (nDSEK in the rabbit cornea, and to investigate the nature of wound healing. Methods. Adult white rabbits (n = 20 were divided in two experimental groups: ten rabbits underwent monocular DSEK, and ten rabbits underwent endothelial keratoplasty without Descemet stripping (nDSEK. On the second postoperative day a horizontal dislocation of the graft was tried using the Lindstrom roller in each animal. Corneas were processed for the light microscopy study. Results. Rolling the Lindstrom instrument over the corneal surface did not cause horizontal dislocation in any of the operated eyes. In the DSEK group light microscopy revealed the lack of inflammation and fibrosis at the clearly distinctive donor-recipient interface (DRI. Retrocorneal membrane was found in two eyes. In nDSEK group, the host Descemet` s membrane (DM was intact without endothelial cells, with good graft apposition, without inflammation, fibrosis, or retrocorneal membrane. Conclusion. This study suggests that there is no difference in graft stability in DSEK compared to nDSEK in rabbit corneas. Wounds healed at DRI by hypocellular scarring only in both experimental groups.

  17. Deep anterior lamellar keratoplasty in the management of keratoconus

    Directory of Open Access Journals (Sweden)

    Rajesh Fogla

    2013-01-01

    Full Text Available Advanced cases of keratoconus often require surgical intervention to restore corneal anatomy and improve eyesight. Penetrating keratoplasty (PK although commonly performed has potential risk of immunological rejection and is now no longer automatically the first choice of surgery. DALK procedures have evolved, which allows surgical replacement of recipient′s corneal stroma, leaving behind healthy descemet membrane (DM and endothelium. This reduces the risk of allograft endothelial rejection and late graft failure. In recent times, DALK techniques have led to significant improvements in visual outcome and current results are comparable to PK. Big bubble technique of DALK has become the most popular among the various surgical techniques described. Manual near DM DALK also gives good outcome although the visual recovery is often delayed. Future integration of femtosecond laser technology along with diagnostic imaging technology is likely to further improve outcomes of DALK in keratoconus.

  18. Laser assisted hybrid additive manufacturing of thermoelectric modules

    Science.gov (United States)

    Zhang, Tao; Tewolde, Mahder; Longtin, Jon P.; Hwang, David J.

    2017-02-01

    Thermoelectric generators (TEGs) are an attractive means to produce electricity, particular from waste heat applications. However, TEGs are almost exclusively manufactured as flat, rigid modules of limited size and shape, and therefore an appropriate mounting for intimate contact of TEGs modules onto arbitrary surfaces represents a significant challenge. In this study, we introduce laser assisted additive manufacturing method to produce multi-layered thermoelectric generator device directly on flat and non-flat surfaces for waste heat recovery. The laser assisted processing spans from laser scribing of thermal sprayed thin films, curing of dispensed thermoelectric inks and selective laser sintering to functionalize thermoelectric materials.

  19. Application of laser assisted cold spraying process for metal deposition

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-02-01

    Full Text Available Laser assisted cold spraying (LACS) process is a hybrid technique that uses laser and cold spray to deposit solid powders on metal substrates. For bonding to occur, the particle velocities must be supersonic which are achieved by entraining...

  20. Respiratory complications after diode-laser-assisted tonsillotomy.

    Science.gov (United States)

    Fischer, Miloš; Horn, Iris-Susanne; Quante, Mirja; Merkenschlager, Andreas; Schnoor, Jörg; Kaisers, Udo X; Dietz, Andreas; Kluba, Karsten

    2014-08-01

    Children with certain risk factors, such as comorbidities or severe obstructive sleep apnea syndrome (OSAS) are known to require extended postoperative monitoring after adenotonsillectomy. However, there are no recommendations available for diode-laser-assisted tonsillotomy. A retrospective chart review of 96 children who underwent diode-laser-assisted tonsillotomy (07/2011-06/2013) was performed. Data for general and sleep apnea history, power of the applied diode-laser (λ = 940 nm), anesthesia parameters, the presence of postoperative respiratory complications and postoperative healing were evaluated. After initially uncomplicated diode-laser-assisted tonsillotomy, an adjustment of post-anesthesia care was necessary in 16 of 96 patients due to respiratory failure. Respiratory complications were more frequent in younger children (3.1 vs. 4.0 years, p = 0.049, 95 % CI -1.7952 to -0.0048) and in children who suffered from nocturnal apneas (OR = 5.00, p diode-laser power higher than 13 W could be identified as a risk factor for the occurrence of a postoperative oropharyngeal edema (OR = 3.45, p diode-laser-assisted tonsillotomy. We recommend a reduced diode-laser power (<13 W) to reduce oropharyngeal edema.

  1. Prospective study on laser-assisted laparascopic partial nephrectomy

    Science.gov (United States)

    Sroka, Ronald; Hennig, Georg; Zilinberg, Katja; Khoder, Wael Y.

    2012-02-01

    Introduction: Developments in laparoscopic partial nephrectomy (LPN) opened a demand for surgical tools compatible with laparoscopic manipulations to make laser assisted technique safe, feasible and reproducible. Warm ischemia and bleeding during laparoscopic partial nephrectomy place technical constraints on surgeons. Therefore it was the aim to develop a safe and effective laser assisted partial nephrectomy technique without need for ischemia. Patients and methods: A diode laser emitting light at 1318nm in cw mode was coupled into a bare fibre (core diameter 600 μm) thus able to transfer up to 100W to the tissue. After dry lab experience, a total of 10 patients suffering from kidney malformations underwent laparoscopic/retroperitoneoscopic partial nephrectomy. Clinically, postoperative renal function and serum c-reactive protein (CRP) were monitored. Laser induced coagulation depth and effects on resection margins were evaluated. Demographic, clinical and follow-up data are presented. Using a commercial available fibre guidance instrument for lanringeal intervention, the demands on an innovative laser fibre guidance instrument for the laser assisted laparoscopic partial nephrectomy (LLPN) are summarized. Results: Overall, all laparascopic intervention were succesfull and could be performed without conversion to open surgery. Mean operative time and mean blood loss were comparable to conventional open and laparascopic approaches. Laser assisted resection of the kidney tissue took max 15min. After extirpation of the tumours all patients showed clinical favourable outcome during follow up period. Tumour sizes were measured to be up 5cm in diameter. The depth of the coagulation on the removed tissue ranged between <1 to 2mm without effect on histopathological evaluation of tumours or resection margin. As the surface of the remaining kidney surface was laser assisted coagulated after removal. The sealing of the surface was induced by a slightly larger coagulation

  2. Femtosecond-assisted preparation of donor tissue for Boston type 1 keratoprosthesis.

    Science.gov (United States)

    Moshirfar, Majid; Neuffer, Marcus C; Kinard, Krista; Lependu, Monette T; Sikder, Shameema

    2011-01-01

    We describe a technique for femtosecond laser-assisted preparation of donor tissue for Boston type 1 keratoprosthesis to provide accurate double punching of the donor tissue for optimized alignment in the visual axis. The technique was reproducibly performed in four donor corneas mounted in an artificial anterior chamber. This technique can provide optically centered donor tissue with smooth trephinated edges.

  3. Challenges in pediatric endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Vikas Mittal

    2014-01-01

    Full Text Available We performed endothelial keratoplasty (EK in three eyes of two siblings (2.5 years, male and 3.5 years, female with congenital hereditary endothelial dystrophy (CHED and report the intraoperative and postoperative difficulties. Repeated iris prolapse, apprehension of crystalline lens touch due to positive vitreous pressure, and need for frequent air injections to attach the graft were intraoperative challenges in all three eyes. These were addressed by use of Sheet′s glide instead of Busin′s glide during graft insertion and suturing of main and side ports before air injection. One eye had graft dislocation on second postoperative day due to eye rubbing by the child. Graft was repositioned with air and a venting incision was created. Postoperative examination required repeated general anesthesia. Corneal edema resolved completely in all three eyes. Present case series highlights the possible intraoperative and postoperative challenges and their solutions in pediatric EK for CHED.

  4. Laser-assisted machining of difficult-to-machine materials

    Energy Technology Data Exchange (ETDEWEB)

    Incropera, F.P.; Rozzi, J.C.; Pfefferkorn, F.E.; Lei, S.; Shin, Y.C.

    1999-07-01

    Laser-assisted machining (LAM) is a hybrid process for which a difficult-to-machine material, such as a ceramic or super alloy, is irradiated by a laser source prior to material removal by a cutting tool. The process has the potential to significantly increase material removal rates, as well as to improve the geometry and properties of the finished work piece. Features and limitations of theoretical and experimental procedures for determining the transient thermal response of a work piece during LAM are described, and representative results are presented for laser-assisted turning of sintered silicon nitride. Significant physical trends are revealed by the calculations, as are guidelines for the selection of appropriate operating conditions.

  5. Complications from laser-assisted liposuction performed by noncore practitioners.

    Science.gov (United States)

    Blum, Craig A; Sasser, Charles G S; Kaplan, Jonathan L

    2013-10-01

    Liposuction is one of the most commonly performed aesthetic surgery procedures in the United States, and most plastic surgeons perform suction-assisted, ultrasound-assisted, or power-assisted liposuction. The past decade has seen a growing interest in laser-assisted liposuction (LAL) and the proposed advantages of traditional liposuction methods. However, it is performed by a minority of plastic surgeons. In fact, many LAL providers are not trained in aesthetic practice, and many offer LAL as their only body-contouring procedure. When only one method of body contouring is available to a provider, it may lead to inappropriate patient selection with associated poor outcomes. This report discusses the use of laser liposuction in body contouring and the demographics of those performing liposuction, including LAL. Complications from laser-assisted liposuction performed by noncore practitioners are illustrated.

  6. Laser Assisted Free-Free Transition in Electron - Atom Collision

    Science.gov (United States)

    Sinha, C.; Bhatia, A. K.

    2011-01-01

    Free-free transition is studied for electron-Hydrogen atom system in ground state at very low incident energies in presence of an external homogeneous, monochromatic and linearly polarized laser field. The incident electron is considered to be dressed by the laser in a non perturbative manner by choosing the Volkov solutions in both the channels. The space part of the scattering wave function for the electron is solved numerically by taking into account the effect of electron exchange, short range as well as of the long range interactions. Laser assisted differential as well as elastic total cross sections are calculated for single photon absorption/emission in the soft photon limit, the laser intensity being much less than the atomic field intensity. A strong suppression is noted in the laser assisted cross sections as compared to the field free situations. Significant difference is noted in the singlet and the triplet cross sections.

  7. Rainbow glare after laser-assisted in situ keratomileusis: a review of literature

    Directory of Open Access Journals (Sweden)

    Moshirfar M

    2016-11-01

    Full Text Available Majid Moshirfar,1,2 Jordan D Desautels,3 Tyler S Quist,4 David F Skanchy,5 Mark T Williams,6 Ryan T Wallace7 1Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, 2HDR Research Center, Hoopes Vision, Draper, UT, 3Tufts University School of Medicine, Boston, MA, 4University of Utah School of Medicine, Salt Lake City, UT, 5McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 6University of California, San Francisco School of Medicine, San Francisco, CA, 7Brigham Young University, Provo, UT, USA Abstract: This article reviews the current literature pertaining to rainbow glare (RG, including incidence rate, clinical presentation, etiology, prognosis, and management. RG is a rare optical complication of femtosecond laser-assisted in situ keratomileusis that results in patients seeing an array of spectral bands surrounding point sources of light under mesopic and scotopic conditions. The mechanism is thought to be a consequence of the formation of a transmissive diffraction grating on the posterior surface of the corneal flap created by the FS laser. RG has a good prognosis and is usually self-limiting. Persistent RG with concomitant residual refractive error may warrant lifting the flap and photoablating the posterior surface of the flap. Patients with persistent RG and no residual refractive error should be considered candidates for phototherapeutic keratectomy on the posterior flap surface. Keywords: rainbow glare, femtosecond, LASIK, keratomileusis, phototherapeutic keratectomy

  8. The effects of laser assisted hatching on pregnancy rates

    OpenAIRE

    Alireza Ghannadi; Marjaneh Kazerooni; Fatemeh Jamalzadeh; Sahar Amiri; Parifar Rostami; Forouzan Absalan

    2011-01-01

    Background: For infertile women aged over 35 years, failure of the ZP (zona pellucida) to rupture is believed to be associated with a decreased implantation rate in in vitro fertilization (IVF) or intra cytoplasmic sperm injection (ICSI). Objective: In this research, laser assisted hatching (LAH) was offered to patients with advanced maternal age to evaluate a possible benefit. Materials and Methods: Nine hundred thirty two cycles of IVF/ICSI in females were analyzed. Women included in this s...

  9. Pulsed laser-assisted machining of Inconel 718 superalloy

    Science.gov (United States)

    Azhdari Tadavani, Soheila; Shoja Razavi, Reza; Vafaei, Reza

    2017-01-01

    Nickel-based superalloys including Inconel 718(IN718) are widely used in aerospace industries due to their superior high temperature strength, toughness, and corrosion resistance. These alloys are difficult to machine mainly because of their low thermal conductivity and high work hardening rate, which cause steep temperature gradient and high cutting forces at the tool edge. The application of laser assisted machining is the subject of many new researches since shear forces; surface coarsening and tool wear are reduced. The aim of this investigation was to evaluate laser assisted machining behavior of a 718 Inconel superalloy from the view point of machining specific energy, surface roughness, tool wear and chip appearance. Experimental apparatuses used included optical and scanning electron microscopy, spark emission spectroscopy, and EDS analysis. The results indicated that increasing the temperature to about 540 °C just ahead of primary shear zone, can result in 35% reduction of machining specific energy, in comparison with conventional machining. Furthermore, surface coarsening and tool wear were reduced by 22% and 23% respectively. Flank wear was the main deteriorating factor on cutting tools during laser assisted machining. SEM micrographs indicated that increase in temperature has no noticeable effect on finished workpiece surface. Analysis of variance obtained from regression analysis indicated that frequency of laser beam has the most influential effect on temperature. The optimum conditions for laser assisted machining of 718 superalloy is suggested as follows: 80 Hz frequency, 400 W power, 24 m/min cutting speed, and 0.052 mm/rev feed rate along with 540 °C temperature, 2.51 J/mm2 machining specific energy and 130 N cutting force.

  10. Laser-assisted new attachment procedure in private practice.

    Science.gov (United States)

    Harris, David M; Gregg, Robert H; McCarthy, Delwin K; Colby, Leigh E; Tilt, Lloyd V

    2004-01-01

    Three private dental practices conducted a retrospective analysis of patients receiving the laser-assisted new attachment procedure (LANAP). Retrospective results were compared to clinical trial data from the University of Texas Health Sciences Center in San Antonio (UTHSCSA) to determine if outcomes from a controlled clinical trial can be duplicated in private practice. Results also are compared with published results of other surgical and nonsurgical therapies for inflammatory periodontal disease.

  11. Process characteristics of fibre-laser-assisted plasma arc welding

    OpenAIRE

    Mahrle, A; SCHNICK, M; Rose, S; Demuth, C; Beyer, E.; Füssel, U

    2011-01-01

    Abstract Experimental and theoretical investigations on fibre-laser assisted plasma arc welding (LAPW) have been performed. Welding experiments were carried out on aluminium and steel sheets. In case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In case of aluminium weldin...

  12. Traumatic wound dehiscence after corneal keratoplasty

    Directory of Open Access Journals (Sweden)

    Patrick Frensel Tzelikis

    2015-10-01

    Full Text Available ABSTRACTPurpose:To assess patient characteristics, risk factors, outcomes, and the treatment of wound dehiscence (WD in patients after corneal keratoplasty.Methods:Retrospective chart review of 11 eyes of 11 patients with corneal grafts who underwent repair of WD from January 1, 2004 to December 31, 2012 at Hospital Oftalmologico de Brasilia.Results:Eight (72.7% patients were men and three were women. Six (54.5% patients had deep anterior lamellar keratoplasty (DALK and 5 had penetrating keratoplasty. The mean age at trauma was 31.1 years. The mean time from corneal keratoplasty to WD was 12.82 months (range, 3-33 months. The mean best-corrected visual acuity of patients before trauma was 20/60 (0.48 logMAR and after final treatment was 20/160 (0.90 logMAR (P=0.15. In one case, visual acuity decreased to no light perception because of retinal detachment and phthisis bulbi. Accidental blunt trauma and fall were the most common causes of WD.Conclusion:Patients who undergo corneal keratoplasty have a life-long risk of WD. The full-thickness rupture at the graft-host junction in our study suggests that the junction remains vulnerable, even following DALK, and can rupture with trauma. In our series, depending upon the severity of the trauma, postkeratoplastic WD can be associated with a good visual prognosis.

  13. Laser-assisted advanced assembly for MEMS fabrication

    Science.gov (United States)

    Atanasov, Yuriy Andreev

    Micro Electro-Mechanical Systems (MEMS) are currently fabricated using methods originally designed for manufacturing semiconductor devices, using minimum if any assembly at all. The inherited limitations of this approach narrow the materials that can be employed and reduce the design complexity, imposing limitations on MEMS functionality. The proposed Laser-Assisted Advanced Assembly (LA3) method solves these problems by first fabricating components followed by assembly of a MEMS device. Components are micro-machined using a laser or by photolithography followed by wet/dry etching out of any material available in a thin sheet form. A wide range of materials can be utilized, including biocompatible metals, ceramics, polymers, composites, semiconductors, and materials with special properties such as memory shape alloys, thermoelectric, ferromagnetic, piezoelectric, and more. The approach proposed allows enhancing the structural and mechanical properties of the starting materials through heat treatment, tribological coatings, surface modifications, bio-functionalization, and more, a limited, even unavailable possibility with existing methods. Components are transferred to the substrate for assembly using the thermo-mechanical Selective Laser Assisted Die Transfer (tmSLADT) mechanism for microchips assembly, already demonstrated by our team. Therefore, the mechanical and electronic part of the MEMS can be fabricated using the same equipment/method. The viability of the Laser-Assisted Advanced Assembly technique for MEMS is demonstrated by fabricating magnetic switches for embedding in a conductive carbon-fiber metamaterial for use in an Electromagnetic-Responsive Mobile Cyber-Physical System (E-RMCPS), which is expected to improve the wireless communication system efficiency within a battery-powered device.

  14. Excimer laser assisted angioplasty in hemodialysis access intervention.

    Science.gov (United States)

    Yevzlin, Alexander S; Urbanes, Aris

    2009-01-01

    A case is described in which an excimer laser is used to assist angioplasty of a severe central venous lesion that is refractory to conventional techniques. Modern laser technology uses the ultraviolet (UV) spectral region to generate nanosecond pulses of energy. This results in photoablation, which is the process by which energy photons cause molecular bond disruption, while minimizing thermal damage to the surrounding vascular tissues. Further investigation of excimer laser assisted angioplasty in the setting of hemodialysis access intervention is needed to rigorously define its potential role. In occlusive disease where no conventional alternative is available, however, laser therapy is a viable option.

  15. Laser-Assisted Removal of Aspirated Thumbtacks by Flexible Bronchoscopy

    Directory of Open Access Journals (Sweden)

    Oren Fruchter

    2010-01-01

    Objectives. To describe a technique for removal of sharp aspirated metal objects employing laser through flexible bronchoscopy. Methods. We report two patients in whom a new technique for removal of sharp aspirated metal objects utilizing Nd-Yag laser flexible bronchoscopy was used. Results. Successful and uncomplicated removal of the aspirated thumbpack by flexible bronchoscopy under conscious sedation was accomplished in the two patients described. Both patients were discharged within 24 hours. Conclusions. In patients with aspirated thumbtack laser-assisted breakage of the object through flexible bronchoscopy may obviate the need for rigid bronchoscopy or thoracotomy.

  16. Laser-assisted cleaning: Dominant role of surface

    Indian Academy of Sciences (India)

    J Padma Nilaya; D J Biswas

    2010-12-01

    Pulsed laser-assisted removal of particulates from substrates has decided advantages over the conventional methods of cleaning. Experiments conducted with loose contamination on metal and transparent dielectric surfaces proved conclusively the dominant role played by the absorption of the incident radiation by the surface towards the generation of the cleaning force as against the absorption in the particulates alone. Further, the presence of transparent/semi-transparent particulates on a metal surface was found to result in an increased absorption of the incident radiation by the substrate. This effect, identified as field-enhanced surface absorption was found to increase with reduction in the average particulate size.

  17. Laser-assisted treatment of patients with hemorrhagic diathesis

    Science.gov (United States)

    Neckel, Claus P.

    2000-03-01

    Today more and more patients with bleeding disorder come to our office for treatment. The number of patients with therapeutic anticoagulation is growing steadily. Discontinuation of this therapy can often be crucial. On the other hand are oralsurgical procedures extremely sensitive to bleeding due to the constant presents of saliva with its high fibrinolytic activity. The aim of this study was to evaluate the use of a surgical diode (wavelength 810 nm) laser as accessory tool in the treatment of patients with hemorrhagic diathesis. Enclosed in the study were 123 patients with: (1) Coumarintherapy, a Quick test ratio of 15 - 25%; (2) More than 300 mg of ASS/die; (3) Hemophilia, a factor activity under 35%; (4) Morbus Werlhof with less than 30000 thrombocytes. 179 Surgical procedures: (1) Tooth extraction 86%; (2) Apexectomy 3%; (3) Tumorexcision 9%; (4) Curettage and flapsurgery 1%; (5) Gingivectomy 1%. All procedures were laser-assisted with a diode laser emitting 810 nm. The glass fibers used were depending on the procedures either 200, 400, or 600 micron. No coagulating agents or tissue adhesives were used in addition. The postoperative outcome and complication rates were compared to substitution therapy and tissue adhesives. Laser-assisted treatment of these patients shows a high predictability and success rate leaving out side effects of drugs and human cryoprecipitates. Postoperative impairment is diminished.

  18. In situ monitoring of single-wall carbon nanotube laser assisted growth

    NARCIS (Netherlands)

    Haluška, M.; Bellouard, Y.; Burgt, Y. van de; Dietzel, A.H.

    2010-01-01

    Laser assisted catalytic chemical vapor deposition has recently emerged as an attractive method for locally growing carbon nanotubes (CNTs) in a cold wall reactor. So far, reported laser assisted CNT growth has been carried out without insitu process monitoring. This has made it difficult to control

  19. Bioceramic 3D Implants Produced by Laser Assisted Additive Manufacturing

    Science.gov (United States)

    Lusquiños, Fernando; del Val, Jesús; Arias-González, Felipe; Comesaña, Rafael; Quintero, Félix; Riveiro, Antonio; Boutinguiza, Mohamed; Jones, Julian R.; Hill, Robert G.; Pou, Juan

    Cranial defect restoration requires a suitable implant capable to fulfill protective and aesthetic functions, such as polymeric and metallic implants. Nevertheless, the former materials cannot provide osteointegration of the implant within the host bone nor implant resorption, which is also required in pediatricorthopedics for normal patient growth. Resorbable and osteoconductivebioceramics are employed, such as silicate bioactive glasses. Nevertheless, manufacturing based on conventional casting in graphite moulds is not effective for warped shape implants suitable for patient tailored treatments. In this work, we analyze the application of rapid prototyping based on laser cladding to manufacture bioactive glass implants for low load bearing bone restoration. This laser-assisted additive technique is capable to produce three-dimensional geometries tailored to patient, with reduced fabrication time and implant composition modification. The obtained samples were characterized; the relationships between the processing conditions and the measured features were studied, in addition to the biological behavior analysis.

  20. Laser-Assisted Elastic Electron Scattering from Argon

    Institute of Scientific and Technical Information of China (English)

    HU Qiu-Bo; SUN Jin-Feng

    2009-01-01

    The second Born approximation (SBA) theory is applied to the study of electron-atom scattering in the presence of a CO2 laser field. The absolute differential cross sections of e-At scattering are calculated with multiphoton exchange in two special scattering geometries G1 (for small-angle scattering) and G2. For geometry G1, compared with the results of two different model potentials for electron elastic scattering by atoms, it is found that electronatom polarization potential plays an important role in laser-assisted electron-atom scattering. Some calculational results in geometries G2 are given. Our results are found to be better than other theoretical results as compared with the experimental data in geometries G1 and G2.

  1. Kinetics of Laser-Assisted Carbon Nanotube Growth

    CERN Document Server

    van de Burgt, Yoeri; Mandamparambil, Rajesh

    2014-01-01

    Laser-assisted chemical vapour deposition (CVD) growth is an attractive mask-less process for growing locally aligned carbon nanotubes (CNTs) in selected places on temperature sensitive substrates. The nature of the localized process results in fast carbon nanotube growth with high experimental throughput. Here, we report on detailed investigation of growth kinetics related to physical and chemical process characteristics. Specifically, the growth kinetics is investigated by monitoring the dynamical changes of reflected laser beam intensity during growth. Benefiting from the fast growth and high experimental throughput, we investigate a wide range of experimental conditions and propose several growth regimes. Rate-limiting steps are determined using rate equations linked to the proposed growth regimes, which are further characterized by Raman spectroscopy and Scanning Electron Microscopy (SEM), therefore directly linking growth regimes to the structural quality of the CNTs. Activation energies for the differe...

  2. Laser-assisted fabrication of highly viscous alginate microsphere

    Science.gov (United States)

    Lin, Yafu; Huang, Yong

    2011-04-01

    Encapsulated microspheres have been widely used in various biomedical applications. However, fabrication of encapsulated microspheres from highly viscous materials has always been a manufacturing challenge. The objective of this study is to explore a novel metallic foil-assisted laser-induced forward transfer (LIFT), a laser-assisted fabrication technique, to make encapsulated microspheres using high sodium alginate concentration solutions. The proposed four-layer approach includes a quartz disk, a sacrificial and adhesive layer, a metallic foil, and a transferred suspension layer. It is found that the proposed four-layer modified LIFT approach provides a promising fabrication technology for making of bead-encapsulated microspheres from highly viscous solutions. During the process, the microsphere only can be formed if the direct-writing height is larger than the critical direct-writing height; otherwise, tail structured droplets are formed; and the encapsulated microsphere diameter linearly increases with the laser fluence and decreases with the sodium alginate concentration.

  3. Laser-assisted delivery of topical methotrexate - in vitro investigations

    DEFF Research Database (Denmark)

    Taudorf, Elisabeth Hjardem

    2016-01-01

    Ablative fractional lasers (AFXL) are increasingly used to treat dermatological disorders and to facilitate laser-assisted topical drug delivery. In this thesis, laser-tissue interactions generated by stacked pulses with a miniaturized low-power 2,940 nm AFXL were characterized (study I). Knowledge...... of the correlation between laser parameters and tissue effects was used to deliver methotrexate (MTX) topically through microscopic ablation zones (MAZs) of precise dimensions. MTX is a well-known chemotherapeutic and anti-inflammatory drug that may cause systemic adverse effects, and topical delivery is thus......, while MAZ width increased linearly with the logarithm of stacked pulses. Results were gathered in a mathematical model estimating relations between laser parameters and specific MAZ dimensions. Impact of MAZ depth on AFXL-assisted topical MTX delivery: Pretreatment by AFXL facilitated topical MTX...

  4. Diode Laser Assisted Filament Winding of Thermoplastic Matrix Composites

    Directory of Open Access Journals (Sweden)

    Claudia Prosperi

    2010-01-01

    Full Text Available A new consolidation method for the laser-assisted filament winding of thermoplastic prepregs is discussed: for the first time a diode laser is used, as well as long glass fiber reinforced polypropylene prepregs. A consolidation apparatus was built by means of a CNC motion table, a stepper motor and a simple tensioner. Preliminary tests were performed in a hoop winding configuration: only the winding speed was changed, and all the other process parameters (laser power, distance from the laser focus, consolidation force were kept constant. Small wound rings with an internal diameter of 25 mm were produced and compression tests were carried out to evaluate the composite agglomeration in dependence of the winding speed. At lower winding speeds, a stronginterpenetration of adjacent layers was observed.

  5. Diffuse epithelial ingrowth after perforating keratoplasty.

    Science.gov (United States)

    Severin, M; Kirchhof, B; Hartmann, C

    1987-01-01

    Diffuse epithelial ingrowth was observed in 2 patients after perforating keratoplasty. Both cases involved a corneal graft after perforating injury with aphakia. In the first patient, the epithelial invasion was probably stimulated by a spatula synecholysis. In this case, the diagnosis was only made by histological investigation after enucleation. In the second patient the epithelial ingrowth was observed 8 months after keratoplasty. The clinical diagnosis was made on the basis of the typical slitlamp findings. In this case, the epithelial invasion led to hypotension with high resistance of outflow measured by electrotonography. In a very close chronological relation to the probable fall of chamber fluid secretion, development of a band-shaped keratopathy was observed.

  6. PENETRATING KERATOPLASTY IN MENTALLY RETARDED PATIENTS

    Directory of Open Access Journals (Sweden)

    Dušica Pahor

    2002-12-01

    Full Text Available Background. Penetrating keratoplasty (PK is rarely performed in mentally retarded patients, first of all because of numerous complications after surgery such as inflammation, self-inflicted injury, injury and because of difficult post-operative treatment. The aim of this study was to present the success of PK in this patients. In 16 years (from May 1984 to May 2000 201 PK were performed, but only three in mentally retarded patients.Methods. We present three cases of PK in mentally retarded patients. All the patients were men. They were 14, 16 and 27 year old. The indication for PK were in two cases acute keratoconus and in one case acute keratoglobus. The mean followup was 24.6 months. Trepanation was made with rotor threpin and donor material was sutured using single continuous 10-0 nylon suture.Results. In two cases keratoplasties stayed clear. Visual acuities were 0,4 and 0,5. In one patient with very aggressive behaviour graft failure developed with significant corneal vascularisation. Re-keratoplasty was not performed.Conclusions. Adequate post-operative care following PK in mentally retarded patients is the most important factor for the success of transplantation. The indication for the surgery must be made very carefully especially in self-aggressive patients in residential care.

  7. Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique)

    NARCIS (Netherlands)

    Van Dooren, BTH; Mulder, PGH; Nieuwendaal, CP; Beekhuis, WH; Melles, GRJ

    PURPOSE: To measure the recipient endothelial cell loss after the Melles technique for deep anterior lamellar keratoplasty. METHODS: In 21 eyes of 21 patients, a deep anterior lamellar keratoplasty procedure was performed. Before surgery and at 6, 12, and 24 months after surgery, specular microscopy

  8. Research Progress on Ocular Surface Changes after Fem-tosecond Laser Small Incision Lenticule Extraction

    Institute of Scientific and Technical Information of China (English)

    Xiangfei Chen; Yan Lu; Chunhong Wang; Zhenping Huang

    2015-01-01

    The femtosecond laser has a number of advantages,.such as short pulse time,.high instantaneous power,.high repetition rate, low monopulse energy, and small thermal effect. Fem-tosecond laser-assisted small incision lenticule extraction (SMILE) is becoming the new direction in refractive surgery, and the ocular surface changes after SMILE are attracting in-creasingly more attention. This article reviews adverse effects, including dry eye, injury of corneal nerves, and ocular sur-face inflammation,.occurring after SMILE.

  9. Surgical adhesives for laser-assisted wound closure

    Science.gov (United States)

    Hodges, Diane E.; McNally-Heintzelman, Karen M.; Welch, Ashley J.

    2001-10-01

    Solid protein solder-doped polymer membranes were developed for laser-assisted tissue repair. Biodegradable polymer membranes of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) (PLGA), poly(ethylene glycol) (PEG), and salt particles, using a solvent-casting and particulate-leaching technique. The membranes provided a porous scaffold that readily absorbed the traditional protein solder composed of serum albumin, indocyanine green dye, and de-ionized water. In vitro investigations were conducted to assess the influence of various processing parameters on the strength of tissue repairs formed using the new membranes. These parameters included PLGA copolymer and PLGA/PEG blend ratios, membrane pore size, initial albumin weight fraction, and laser irradiance used to denature the solder. Altering the PLGA copolymer ratio had little effect on repair strength, however such variations are known to influence the degradation rate of the membranes. The repair strength increased with increased membrane pore size and bovine serum albumin concentration. The addition of PEG during the membrane casting stage increased the flexibility of the membranes but not necessarily the repair strength. Typically, the repair strength increased with increasing irradiance from 12 to 18 W/cm2. The new solder-doped polymer membranes provided all of the benefits associated with solid protein solders including high repair strength and improved edge coaptation. In addition, the flexible, moldable nature of the new membranes offers the capability of tailoring the membranes to a wide range of clinically relevant geometries.

  10. Minimally invasive laser-assisted treatment of arytenoid chondritis

    Science.gov (United States)

    Sullins, Kenneth E.

    2001-05-01

    Five adult performance horses presented with the complaints of exercise intolerance and/or upper airway noise. Endoscopy revealed reduced arytenoid movement, mucosal defects with protruding granulation masses and occasional perilaryngeal swelling. While standing, a 1-cm stab incision was created, and a 5-mm trocar with sleeve was inserted through the cricothyroid membrane using nasopharyngeal endoscopic guidance. A fiber guide containing a 600-micron diode free-beam laser fiber was inserted, and the masses were ablated to the cartilage surface. Lesions determined to be limited to the cartilage substance were further ablated using the laser. Lesions determined to extend through the cartilage were manually debrided using an angled curette. The wounds were left unsutured after placing 2-3 ml of antiseptic ointment subcutaneously. Reexamination revealed resolution of the lesions in all horses, and arytenoid mobility was present. Lesions affecting the corniculate process (two) resulted in noticeable atrophy. The author concludes that laser-assisted debridement of septic tracts in the arytenoid cartilages that have not become completely deformed by the process is a reasonable procedure to restore athletic function.

  11. Laser-Assisted in situ Keratomileusis for Hyperopic Defects

    Directory of Open Access Journals (Sweden)

    Ester Novoa Sánchez

    2014-06-01

    Full Text Available Background: currently, LASIK is one of the most common surgical procedures for refractive disorders, including hyperopic defects. Objective: to assess the results of laser-assisted in situ keratomileusis for the treatment of hyperopic defects. Methods: an ambispective study was conducted in 31 eyes (16 patients operated on for hyperopia and simple and compound hyperopic astigmatism in the Refractive Surgery Unit of the Ophthalmology Department of the Hermanos Ameijeiras Hospital between January 2009 and December 2010. Visual acuity with and without optical correction, spherical and astigmatic component before and after surgery and intra- and postoperative complications were analyzed. Results: patients aged 40 to 49 years predominated; compound hyperopic astigmatism was the most frequent defect; the mean uncorrected visual acuity improved and remained stable up to six months after surgery; the average values were 0.87 for moderate defects and 0.79 for high defects with optical correction. The mean sphero-cylindrical component decreased. The efficacy and safety rates were acceptable for moderate and high degrees of the defects and predictability was 100 % for all degrees of ametropia. Conclusion: LASIK is a safe, effective and predictable procedure to treat patients with moderate and high degrees hyperopia and hyperopic astigmatism.

  12. Process characteristics of fibre-laser-assisted plasma arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Mahrle, A; Schnick, M; Rose, S; Demuth, C; Beyer, E; Fuessel, U, E-mail: achim.mahrle@iws.fraunhofer.de [Dresden University of Technology, Institute of Surface and Manufacturing Technology, PO Box, D-01062 Dresden (Germany)

    2011-08-31

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  13. Realizing the Harper Hamiltonian with laser-assisted tunneling in optical lattices.

    Science.gov (United States)

    Miyake, Hirokazu; Siviloglou, Georgios A; Kennedy, Colin J; Burton, William Cody; Ketterle, Wolfgang

    2013-11-01

    We experimentally implement the Harper Hamiltonian for neutral particles in optical lattices using laser-assisted tunneling and a potential energy gradient provided by gravity or magnetic field gradients. This Hamiltonian describes the motion of charged particles in strong magnetic fields. Laser-assisted tunneling processes are characterized by studying the expansion of the atoms in the lattice. The band structure of this Hamiltonian should display Hofstadter's butterfly. For fermions, this scheme should realize the quantum Hall effect and chiral edge states.

  14. Laser-assisted cold-sprayed hydroxyapatite/titanium composites: evaluation for tissues engineering applications

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2013-08-01

    Full Text Available -1 Laser-assisted cold-sprayed hydroxyapatite/titanium composites: evaluation for tissues engineering applications Monnamme Tlotleng, Mukul Shukla, Esther Akinlabi and Sisa Pityana AIMS AND OBJECTIVES This research work seeks to establish titanium... and hydroxyapatite (Ti-HAP) using Laser- Assisted Cold Spray (LACS) technique on Ti-6Al-4V substrate. The produced coatings must be characterised for: a) Micro-structure (porosity, cracks, etc.) using Optical Microscope (OM); b) Mechanical properties (Hardness...

  15. Formation of plano-convex micro-lens array in fused silica glass using CO2 laser assisted reshaping technique

    CERN Document Server

    Sohn, Ik-Bu; Yoo, Dongyoon; Noh, Young-Chul; Ahsan, Md Shamim; Sung, Jae-Hee; Lee, Seong-Ku

    2016-01-01

    We report on fabricating high-fill-factor plano-convex spherical and square micro-lens arrays on fused silica glass surface using CO2 laser assisted reshaping technique. Initially, periodic micro-pillars have been encoded on the glass surface by means of a femtosecond laser beam. Afterwards, the micro-pillars are polished several times by irradiating a CO2 laser beam on top of the micro-pillars. Consequently, spherical micro-lens array with micro-lens size of 50 um x 50 um and square micro-lens array with micro-lens size of 100 um x 100 um are formed on fused silica glass surface. We also study the intensity distribution of light passed through the spherical micro-lens array engraved glass sample. The simulation result shows that, the focal length of the spherical micro-lens array is 35 um. Furthermore, we investigate the optical properties of the micro-lens array engraved glass samples. The proposed CO2 laser based reshaping technique is simple and fast that shows promises in fabrication arrays of smooth mic...

  16. The effects of laser assisted hatching on pregnancy rates

    Directory of Open Access Journals (Sweden)

    Alireza Ghannadi

    2011-01-01

    Full Text Available Background: For infertile women aged over 35 years, failure of the ZP (zona pellucida to rupture is believed to be associated with a decreased implantation rate in in vitro fertilization (IVF or intra cytoplasmic sperm injection (ICSI.Objective: In this research, laser assisted hatching (LAH was offered to patients with advanced maternal age to evaluate a possible benefit.Materials and Methods: Nine hundred thirty two cycles of IVF/ICSI in females were analyzed. Women included in this study were allocated in 4 groups. In group I and II, embryos were cultured and transferred with and without LAH in women aged ≤35, whereas embryos of group III and IV were examined with and without LAH in women aged ≥ 35. Laser manipulations were performed using a suturn-Tm3 system using 2-3 pulses of 0.8 millisecond with 400 voltage duration. The size of the hole made in the zona was measured to be 5-10 μm, depending on the zona thickness of each individual embryo.Results: The performance of LAH significantly increased clinical pregnancy rates in all patients. In group I and II, the chemical (50.99% and 31.61% respectively, clinical (50% and 30.69% respectively and multiple pregnancies (22.27% and 5.94% respectively significantly differ between these groups. In the patients with advanced female age ≥35 the performance of LAH significantly increased chemical (30.12% and clinical pregnancy (27.71% rates compared to whom without LAH (18.96% and 16.37% respectively.Conclusion: Our data demonstrate in the patients who were less than 35 years old, multiple pregnancy rates were significantly increased compared to other groups who aged over 35 years old. In addition benefit of LAH in improving pregnancy rates after IVF or ICSI in women of advanced age (≥35 was shown

  17. The effects of laser assisted hatching on pregnancy rates

    Science.gov (United States)

    Ghannadi, Alireza; Kazerooni, Marjaneh; Jamalzadeh, Fatemeh; Amiri, Sahar; Rostami, Parifar; Absalan, Forouzan

    2011-01-01

    Background: For infertile women aged over 35 years, failure of the ZP (zona pellucida) to rupture is believed to be associated with a decreased implantation rate in in vitro fertilization (IVF) or intra cytoplasmic sperm injection (ICSI). Objective: In this research, laser assisted hatching (LAH) was offered to patients with advanced maternal age to evaluate a possible benefit. Materials and Methods: Nine hundred thirty two cycles of IVF/ICSI in females were analyzed. Women included in this study were allocated in 4 groups. In group I and II, embryos were cultured and transferred with and without LAH in women aged ≤35, whereas embryos of group III and IV were examined with and without LAH in women aged ≥ 35. Laser manipulations were performed using a suturn-Tm3 system using 2-3 pulses of 0.8 millisecond with 400 voltage duration. The size of the hole made in the zona was measured to be 5-10 µm, depending on the zona thickness of each individual embryo. Results: The performance of LAH significantly increased clinical pregnancy rates in all patients. In group I and II, the chemical (50.99% and 31.61% respectively), clinical (50% and 30.69% respectively) and multiple pregnancies (22.27% and 5.94% respectively) significantly differ between these groups. In the patients with advanced female age ≥35 the performance of LAH significantly increased chemical (30.12%) and clinical pregnancy (27.71%) rates compared to whom without LAH (18.96% and 16.37% respectively). Conclusion: Our data demonstrate in the patients who were less than 35 years old, multiple pregnancy rates were significantly increased compared to other groups who aged over 35 years old. In addition benefit of LAH in improving pregnancy rates after IVF or ICSI in women of advanced age (≥35) was shown. PMID:25587254

  18. Techniques for posterior lamellar keratoplasty through a scleral incision

    NARCIS (Netherlands)

    Melles, GRJ; Kamminga, N

    2003-01-01

    Purpose. To describe several techniques for posterior lamellar keratoplasty through a scleral incision, for management of corneal endothelial disorders like pseudophacic bullous keratopathy and Fuchs' endothelial dystrophy, and to report the mid-term clinical results. Methods. Three techniques have

  19. Contrast and glare testing in keratoconus and after penetrating keratoplasty

    National Research Council Canada - National Science Library

    Pesudovs, K; Schoneveld, P; Seto, R J; Coster, D J

    2004-01-01

    To compare the performance of keratoconus, penetrating keratoplasty (PK), and control subjects on clinical tests of contrast and glare vision, to determine whether differences in vision were independent of visual acuity (VA...

  20. Histology of corneal wound healing after deep lamellar endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Chaoran Zhang

    2008-03-01

    Full Text Available Chaoran Zhang1, Jianjiang Xu1, Rongjia Chen21Ophthalmology Department, 2Pathology Department, Eye and Ear Nose Throat Hospital, Fudan University, Shanghai, ChinaAbstract: Deep lamellar endothelial keratoplasty (DLEK has become an alternative procedure for bullous keratopathy. Herein, the histopathological characteristics of corneal wound healing after DLEK were reported. A 71-year-old man suffering from left psuedophakia bullous keratopathy received small incision DLEK. Twenty months later, another penetrating keratoplasty (PK was performed because of the graft failure. The histopathology of the corneal button removed during PK demonstrated the regularity of stromal fiber alignment at the graft interface. Fibrotic repair was limited to the peripheral margins.Keywords: Deep lamellar endothelial keratoplasty, DLEK, bullous keratopathy, penetrating keratoplasty

  1. Indications of Optical Coherence Tomography in Keratoplasties: Literature Review

    Directory of Open Access Journals (Sweden)

    Thiago Trindade Nesi

    2012-01-01

    Full Text Available Optical coherence tomography (OCT of the anterior segment, in particular corneal OCT, has become a reliable tool for the cornea specialist, as it provides the acquisition of digital images at high resolution with a noncontact technology. In penetrating or lamellar keratoplasties, OCT can be used to assess central corneal thickness and pachymetry maps, as well as precise measurements of deep stromal opacities, thereby guiding the surgeon to choose the best treatment option. OCT has also been used to evaluate the keratoplasty postoperative period, for early identification of possible complications, such as secondary glaucoma or donor disc detachments in endothelial keratoplasties. Intraoperatively, OCT can be used to assess stromal bed regularity and transparency in anterior lamellar surgeries, especially for those techniques in which a bare Descemet’s membrane is the goal. The purpose of this paper is to review and discuss the role of OCT as a diagnostic tool in various types of keratoplasties.

  2. Compliance of laser-assisted microvascular anastomosis: a comparative study with manual anastomosis (preliminary results)

    Science.gov (United States)

    Demaria, Roland G.; Lhote, Francois-Marie; Dauzat, Michel; Juan, Jean-Marie; Oliva-Lauraire, Marie-Claire; Durrleman, Nicolas; Delacretaz, Guy P.; Albat, Bernard; Frapier, Jean-Marc; Chaptal, Paul-Andre; Godlewski, Guilhem

    1999-01-01

    The compliance of microvascular anastomosis is an important predictive factor for long term patency of graft or vascular reconstruction. This experimental study compare the compliance of manual suture and laser assisted end to end microvascular anastomosis. In nine New-Zealand white rabbits we performed manual end-to-end suture anastomosis on the left femoral artery and laser assisted anastomosis on the right femoral artery, with a diode laser (wavelength 988 nm, power output 500 mW). Compliance was obtained by echotracking (CBI 8000 sonomicrometry system with 20 MHz implantable microprobe from Crystal-Biotech, USA) on the anastomosis site as well as upstream, and downstream from the anastomosis. Vessel compliance was lower on the manual suture side compared to the laser assisted anastomosis side, especially downstream from the anastomosis.

  3. Use and Evaluation of a Cooling Aid in Laser-Assisted Dental Surgery: An Innovative Study.

    Science.gov (United States)

    Bernardi, Sara; Mummolo, Stefano; Zeka, Keti; Pajewski, Leonardo; Continenza, Maria Adelaide; Marzo, Giuseppe

    2016-06-01

    The aim of this study was to evaluate the beneficial effect of NeoHeal during laser-assisted oral surgery. Laser-assisted surgery is a less invasive technique than conventional surgery using a blade; however, the heat produced by the laser can damage tissue proximal to the treated area. We hypothesized the hydrogel NeoHeal could be applied during oral surgery and have similar benefits as those already described for dermatological surgery. In our randomized controlled trial, we first selected 30 patients who were to undergo laser surgical intervention using a diode laser. Both at the end of intervention and at follow-up, each patient filled out a questionnaire comprising two questions. The answers to the questions were statistically analyzed with regard to frequency of each response, and validated by the Wilcoxon test with a p value cooling aid in laser-assisted dental surgery.

  4. Laser-assisted delivery of topical methotrexate - in vitro investigations.

    Science.gov (United States)

    Taudorf, Elisabeth Hjardem

    2016-06-01

    Ablative fractional lasers (AFXL) are increasingly used to treat dermatological disorders and to facilitate laser-assisted topical drug delivery. In this thesis, laser-tissue interactions generated by stacked pulses with a miniaturized low-power 2,940 nm AFXL were characterized (study I). Knowledge of the correlation between laser parameters and tissue effects was used to deliver methotrexate (MTX) topically through microscopic ablation zones (MAZs) of precise dimensions. MTX is a well-known chemotherapeutic and anti-inflammatory drug that may cause systemic adverse effects, and topical delivery is thus of potential benefit. The impact of MAZ depth (study II) and transport kinetics (study III) on MTX deposition in skin as well as transdermal permeation was determined in vitro. Quantitative analyses of dermal and transdermal MTX concentrations were performed by high performance liquid chromatography (HPLC) (study II & III), while qualitative analyses of MTX biodistribution in skin were illustrated and semi-quantified by fluorescence microscopy (study II & III) and desorption electro spray mass spectrometry imaging (DESI-MSI) (study III). Laser-tissue interactions generated by AFXL: AFXL-exposure generated a variety of MAZ-dimensions. MAZ depth increased linearly with the logarithm of total energy delivered by stacked pulses, but was also affected by variations in power, pulse energy, pulse duration, and pulse repetition rate. Coagulation zones lining MAZs increased linearly with the applied total energy, while MAZ width increased linearly with the logarithm of stacked pulses. Results were gathered in a mathematical model estimating relations between laser parameters and specific MAZ dimensions. Impact of MAZ depth on AFXL-assisted topical MTX delivery: Pretreatment by AFXL facilitated topical MTX delivery to all skin layers. Deeper MAZs increased total MTX deposition in skin compared to superficial MAZs and altered the intradermal biodistribution profile towards

  5. First Demonstration of Laser-Assisted Charge Exchange for Microsecond Duration H- Beams

    Science.gov (United States)

    Cousineau, Sarah; Rakhman, Abdurahim; Kay, Martin; Aleksandrov, Alexander; Danilov, Viatcheslav; Gorlov, Timofey; Liu, Yun; Plum, Michael; Shishlo, Andrei; Johnson, David

    2017-02-01

    This Letter reports on the first demonstration of laser-assisted H- charge exchange for microsecond duration H- beam pulses. Laser-assisted charge exchange injection is a breakthrough technology that overcomes long-standing limitations associated with the traditional method of producing high intensity, time structured beams of protons in accelerators via the use of carbon foils for charge exchange injection. The central theme of this experiment is the demonstration of novel techniques that reduce the laser power requirement to allow high efficiency stripping of microsecond duration beams with commercial laser technology.

  6. A Comparison of Different Operating Systems for Femtosecond Lasers in Cataract Surgery

    Directory of Open Access Journals (Sweden)

    B. M. Wu

    2015-01-01

    Full Text Available The introduction of femtosecond lasers is potentially a major shift in the way we approach cataract surgery. The development of increasingly sophisticated intraocular lenses (IOLs, coupled with heightened patient expectation of high quality postsurgical visual outcomes, has generated the need for a more precise, highly reproducible and standardized method to carry out cataract operations. As femtosecond laser-assisted cataract surgery (FLACS becomes more commonplace in surgical centers, further evaluation of the potential risks and benefits needs to be established, particularly in the medium/long term effects. Healthcare administrators will also have to weigh and balance out the financial costs of these lasers relative to the advantages they put forth. In this review, we provide an operational overview of three of five femtosecond laser platforms that are currently commercially available: the Catalys (USA, the Victus (USA, and the LDV Z8 (Switzerland.

  7. Precise femtosecond laser ablation of dental hard tissue: preliminary investigation on adequate laser parameters

    Science.gov (United States)

    Hikov, Todor; Pecheva, Emilia; Montgomery, Paul; Antoni, Frederic; Leong-Hoi, Audrey; Petrov, Todor

    2017-01-01

    This work aims at evaluating the possibility of introducing state-of-the-art commercial femtosecond laser system in restorative dentistry by maintaining well-known benefits of lasers for caries removal, but also in overcoming disadvantages such as thermal damage of irradiated substrate. Femtosecond ablation of dental hard tissue is investigated by changing the irradiation parameters (pulsed laser energy, scanning speed and pulse repetition rate), assessed for enamel and dentin. The femtosecond laser system used in this work may be suitable for cavity preparation in dentin and enamel, due to the expected effective ablation and low temperature increase when using ultra short laser pulses. If adequate laser parameters are selected, this system seems to be promising for promoting a laser-assisted, minimally invasive approach in restorative dentistry.

  8. A Comparison of Different Operating Systems for Femtosecond Lasers in Cataract Surgery.

    Science.gov (United States)

    Wu, B M; Williams, G P; Tan, A; Mehta, J S

    2015-01-01

    The introduction of femtosecond lasers is potentially a major shift in the way we approach cataract surgery. The development of increasingly sophisticated intraocular lenses (IOLs), coupled with heightened patient expectation of high quality postsurgical visual outcomes, has generated the need for a more precise, highly reproducible and standardized method to carry out cataract operations. As femtosecond laser-assisted cataract surgery (FLACS) becomes more commonplace in surgical centers, further evaluation of the potential risks and benefits needs to be established, particularly in the medium/long term effects. Healthcare administrators will also have to weigh and balance out the financial costs of these lasers relative to the advantages they put forth. In this review, we provide an operational overview of three of five femtosecond laser platforms that are currently commercially available: the Catalys (USA), the Victus (USA), and the LDV Z8 (Switzerland).

  9. Long-term safety and efficacy follow-up of prophylactic higher fluence collagen cross-linking in high myopic laser-assisted in situ keratomileusis

    Directory of Open Access Journals (Sweden)

    Kanellopoulos AJ

    2012-07-01

    Full Text Available Anastasios John KanellopoulosLaservision.gr Institute, Athens, Greece, and New York University Medical School, New York, NY, USABackground: The purpose of this study was to evaluate the safety and efficacy of ultraviolet A irradiation cross-linking on completion for cases of high myopic laser-assisted in situ keratomileusis (LASIK.Methods: Forty-three consecutive LASIK cases treated with femtosecond laser flap and the WaveLight excimer platform were evaluated perioperatively for uncorrected visual acuity, best corrected spectacle visual acuity, refraction, keratometry, topography, total and flap pachymetry, corneal optical coherence tomography, and endothelial cell count. All eyes at the completion of LASIK had cross-linking through the repositioned flap, with higher fluence (10 mW/cm2 ultraviolet light of an average 370 µm wavelength and 10 mW/cm2 fluence applied for 3 minutes following an earlier single instillation of 0.1% riboflavin within the flap interface. Mean follow-up duration was 3.5 (range 1.0–4.5 years.Results: Mean uncorrected visual acuity changed from 0.2 to 1.2, best corrected spectacle visual acuity from 1.1 to 1.2, spherical equivalent from -7.5 diopters (D to -0.2 D, keratometry from 44.5 D to 38 D, flap pachymetry from 105 µm to, total pachymetry from 525 to 405, and endothelial cell count from 2750 to 2800. None of the cases developed signs of ectasia or significant regression during follow-up.Conclusion: Prophylactic collagen cross-linking for high-risk LASIK cases appears to be a safe and effective adjunctive treatment for refractive regression and potential ectasia. This application may be viewed as prophylactic customization of the biomechanical behavior of corneal collagen.Keywords: prophylactic collagen cross-linking, laser-assisted in situ keratomileusis, high-risk, post-LASIK ectasia

  10. Laser assisted cold spraying of aluminium alloy powder on stainless steel substrate

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2012-12-01

    Full Text Available International Conference on Information Warfare and Security, Denver, USA 25-26 March 2013 LASER ASSISTED COLD SPRAYING OF ALUMINIUM ALLOY POWDER ON STAINLESS STEEL SUBSTRATE M. Tlotleng1, 2; E.O. Olakanmi2; C. Meacock; Sisa Pityana1, 3; E.T. Akinlabi2...

  11. Miniaturized reaction chamber for optimized laser-assisted carbon nanotube growth

    NARCIS (Netherlands)

    Burgt, Y. van de; Loon, W. van; Mandamparambil, R.; Bellouard, Y.

    2014-01-01

    The localized growth of carbon nanotube structures has potential in many applications such as interconnects, field emitters and sensors. Using a laser to locally heat the substrate offers a highly versatile process compatible with a broad range of substrates and devices. However, for laser-assisted

  12. Fundamentals of laser-assisted fabrication of inorganic and organic films

    DEFF Research Database (Denmark)

    Schou, Jørgen

    2008-01-01

    The standard method for producing films by laser-assisted methods, Pulsed Laser Deposition (PLD) will be reviewed. The films considered are usually inorganic films, but also films of organic materials have been produced. Also the deposition of organic films by MAPLE (Matrix Assisted Pulsed Laser ...

  13. A Laser-Assisted Anastomotic Technique : Feasibility on Human Diseased Coronary Arteries

    NARCIS (Netherlands)

    Stecher, David; Bronkers, Glenn; Vink, Aryan; Homoet-van der Kraak, Petra H|info:eu-repo/dai/nl/313984166; Helthuis, Jasper; Pasterkamp, Gerard|info:eu-repo/dai/nl/138488304; Buijsrogge, Marc P|info:eu-repo/dai/nl/24420098X

    2016-01-01

    OBJECTIVE: Atherosclerotic disease might hamper the efficacy of the Excimer laser-assisted Trinity Clip anastomotic connector in coronary arteries. Therefore, its efficacy was evaluated on human diseased coronary arteries (study 1). In addition, the acute laser effects onto the coronary wall were as

  14. Low-temperature laser assisted CBE-growth of AlGaAs

    Science.gov (United States)

    Jothilingam, R.; Farrell, T.; Joyce, T. B.; Goodhew, P. J.

    1998-06-01

    We report preliminary studies of low-temperature (335-400°C) chemical beam epitaxial (CBE) growth of Al xGa 1- xAs on GaAs(0 0 1) using triethylgallium (TEG), trimethylaminealane (TMAA) and thermally precracked Arsine (AsH 3) as precursors. We also report results of Ar + laser assisted chemical beam epitaxial growth over the same temperature range. The growth rate for both assisted and unassisted growth as a function of substrate temperature, laser power and precursor beam pressures was determined using laser reflectometry in which the Ar + laser was also used as the probe. In the nonlaser assisted growth Al incorporation is observed to be significantly higher than would be expected at the normal growth temperature of 500°C. With laser assistance the Al concentration, while higher than that at normal growth temperatures, is less than that without laser assistance and the growth rate is higher. These observations, which extended Abernathy's early results to higher nominal Al concentration, are discussed in terms of the relative enhancement of the decomposition of TEG and the alane during laser assistance. Using literature values of the refractive index of AlGaAs alloys at the growth temperature, laser reflectometry was used to monitor both composition and growth rate over a range of growth temperatures. Reflectometry data were compared with the results of Auger Electron Microscopy (AES) and Dektak stylus profiling.

  15. Evaluation and further development of the Excimer Laser Assisted Non-occlusive Anastomosis (ELANA) technique

    NARCIS (Netherlands)

    van Doormaal, T.P.C.

    2010-01-01

    The research described in this thesis had 2 main goals. The first goal was to evaluate the clinical results of the Excimer Laser Assisted Non-occlusive Anastomosis (ELANA) technique. The most important subgroups of patients were separately evaluated in the first part of this thesis (chapters 2 to 5)

  16. Microstructure-sensitive flow stress modeling for force prediction in laser assisted milling of Inconel 718

    Directory of Open Access Journals (Sweden)

    Pan Zhipeng

    2017-01-01

    Full Text Available Inconel 718 is a typical hard-to-machine material that requires thermally enhanced machining technology such as laser-assisted milling. Based upon finite element analysis, this study simulates the forces in the laser-assisted milling process of Inconel 718 considering the effects of grain growth due to γ' and γ" phases. The γ" phase is unstable and becomes the δ phase, which is likely to precipitate at a temperature over 750 °C. The temperature around the center of spot in the experiments is 850 °C, so the phase transformation and grain growth happen throughout the milling process. In the analysis, this study includes the microstructure evolution while accounting for the effects of dynamic recrystallization and grain growth through the Avrami model. The grain growth reduces the yield stress and flow stress, which improves the machinability. In finite element analysis (FEA, several boundary conditions of temperature varying with time are defined to simulate the movement of laser spot, and the constitutive model is described by Johnson-Cook equation. In experiments, this study collects three sets of cutting forces and finds that the predicted values are in close agreements with measurements especially in feed direction, in which the smallest error is around 5%. In another three simulations, this study also examines the effect of laser preheating on the cutting forces by comparison with a traditional milling process without laser assist. When the laser is off, the forces increase in all cases, which prove the softening effect of laser-assisted milling. In addition, when the axial depth of milling increases, the laser has a more significant influence, especially in axial direction, in which the force with laser is more than 18% smaller than the one without laser. Overall, this study validates the influence of laser-assisted milling on Inconel 718 by predicting the cutting forces in FEA.

  17. Contact Lens Visual Rehabilitation in Keratoconus and Corneal Keratoplasty

    Directory of Open Access Journals (Sweden)

    Yelda Ozkurt

    2012-01-01

    Full Text Available Keratoconus is the most common corneal distrophy. It’s a noninflammatory progressive thinning process that leads to conical ectasia of the cornea, causing high myopia and astigmatism. Many treatment choices include spectacle correction and contact lens wear, collagen cross linking, intracorneal ring segments implantation and finally keratoplasty. Contact lenses are commonly used to reduce astigmatism and increase vision. There are various types of lenses are available. We reviewed soft contact lenses, rigid gas permeable contact lenses, piggyback contact lenses, hybrid contact lenses and scleral-semiscleral contact lenses in keratoconus management. The surgical option is keratoplasty, but even after sutur removal, high astigmatism may stil exists. Therefore, contact lens is an adequate treatment option to correct astigmatism after keratoplasty.

  18. Development prospects of keratoplasty in Moscow

    Directory of Open Access Journals (Sweden)

    E. M. Kildyushov

    2013-01-01

    Full Text Available A retrospective analysis of the statistical data for the years 2010‑2012 on mortality and the donor selection of the Bureau of Forensic Pathology of Moscow, Department of Forensic Pathology of Pirogov N. I. Russian National Research Medical University and ILab Eye Bank in order to determine the possible number of keratoplastic surgeries. The results of statistical data analysis testify to the fact that the number of available donor material is not sufficient to meet the needs for keratoplastic material and it is necessary to create eye banks, which would have provided this need. It is necessary to create eye banks, that possess a clear logistics chain of intake donor tissue, preliminary assessment of the donor tissue, laboratory diagnostics of the donor’s blood and delivery of tissue to the Bank. Theeye bank should not only produce preserved material for keratoplasty, but also carry out full morpho-functional assessment of material and its subsequent delivery to consumers in health facilities.

  19. Spontaneous wound dehiscence after penetrating keratoplasty

    Institute of Scientific and Technical Information of China (English)

    Alireza; Foroutan; Seyed; Ali; Tabatabaei; Mahmoud; Jabbarvand; Behrouz; Reza; Zarei; Mohammad; Soleimani

    2014-01-01

    Spontaneous wound separation may be developed even months after suture removal especially in the context of long-term corticosteroid therapy. A 68-yearold Caucasian woman presented to our cornea clinic with spontaneous wound dehiscence after her third penetrating keratoplasty(PKP) which was performed three years ago. An Ahmed glaucoma valve(New World Medical, Ranchos Cucamonga, CA) was inserted ten months after the third PKP, which successfully controlled intraocular pressure(IOP). At the examination, the last sutures were removed eight months ago and she was using flourometholone 0.1%(Sina Darou, Tehran, Iran)with a dose of once a day. There was one quadrant of wound dehiscence from 8 to 11 o`clock associated with anterior wound gape and severe corneal edema.Resuturing was performed for the patient. At the one month examination, the corneal edema was resolved and best corrected visual acuity was 20/200 mainly due to previous glaucomatous optic neuropathy. Caution about the prolonged use of corticosteroids is necessary. Topical immunosuppressives could be a promising choice in this field.

  20. Analysis of low-energy and high-frequency femtosecond laser for the construction of deep anterior donor corneal lamellae

    Directory of Open Access Journals (Sweden)

    Gustavo Victor

    2014-04-01

    Full Text Available Purpose: To evaluate the efficacy and reliability of a low-energy femtosecond laser with a high repetition rate for construction of deep anterior donor corneal lamellae. Methods: This was a prospective laboratory investigation. Twenty-five human corneal buttons were femtosecond laser cut to create thick anterior lamellae (diameter, 10mm; thickness, 500µm. The laser cuts were made using an LDV® femtosecond laser in a Ziemer® anterior chamber. To obtain a better edge, the lamellae were trephined with an 8mm trephine (Katena®. The central corneal thickness and the anterior lamellae were measured using a Mitutoyo® thickness gauge with an accuracy of 0.001mm. Results: The central thickness of the 25 corneas ranged from 500 to 705µm (mean, 584 ± 51µm. The thickness of the anterior lamellae ranged from 420 to 480µm (mean, 455 ± 12.7µm. The anterior lamellae diameters were 7.90 ± 0.1mm, and all laser cuts were round. The lamellar interfaces appeared regular by surgical microscopy. There were no cases of inter-lamellar adhesion. Conclusion: The LDV® femtosecond laser appears to be a safe and reliable instrument for cutting deep anterior lamellae from donor corneoscleral buttons. Minimal variation in donor lamellar depth with the laser will be useful for creating donor corneal tissue for deeper anterior lamellar keratoplasty or endothelial keratoplasty surgery or both from a single donor cornea.

  1. Confocal microscopy findings in deep anterior lamellar keratoplasty performed after Descemet's stripping automated endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Pang A

    2014-01-01

    Full Text Available Audrey Pang,1,2 Karim Mohamed-Noriega,1 Anita S Chan,1,3–5 Jodbhir S Mehta1,3 1Singapore National Eye Centre, 2Department of Ophthalmology, Tan Tock Seng Hospital, 3Singapore Eye Research Institute, 4Department of Histopathology, Pathology, Singapore General Hospital, 5Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore Background: This study describes the in vivo confocal microscopy findings in two patients who had deep anterior lamellar keratoplasty (DALK following Descemet's stripping automated endothelial keratoplasty (DSAEK. Methods: The study reviewed the cases of two patients who first underwent DSAEK followed by DALK when their vision failed to improve due to residual stromal scarring. In the first case, a DSAEK was performed for a patient with pseudophakic bullous keratopathy. After surgery, the patient's vision failed to improve satisfactorily due to residual anterior stromal opacity and irregularity. Subsequently, the patient underwent a DALK. The same two consecutive operations were performed for a second patient with keratoconus whose previous penetrating keratoplasty had failed and had secondary graft ectasia. In vivo confocal microscopy was performed 2 months after the DALK surgery in both cases. Results: At 3 months after DALK, the best-corrected visual acuity was 6/30 in case 1 and 6/24 in case 2. In vivo confocal microscopy in both cases revealed the presence of quiescent keratocytes in the stroma layers of the DSAEK and DALK grafts, which was similar in the central and peripheral cornea. There was no activated keratocytes or haze noted in the interface between the grafts. Conclusion: Our short-term results show that performing a DALK after a DSAEK is an effective way of restoring cornea clarity in patients with residual anterior stromal opacity. In vivo confocal microscopy showed that there were no activated keratocytes seen in the interface of the grafts, which suggests

  2. Acute Comitant Esotropia Following Penetrating Keratoplasty

    Directory of Open Access Journals (Sweden)

    Abbas Bagheri

    2008-12-01

    Full Text Available

    PURPOSE: To report a case of acute comitant esotropia in a patient with bilateral keratoconus presenting after penetrating keratoplasty (PKP in the fellow eye. CASE REPORT: A 17-year-old male patient with bilateral keratoconus underwent PKP in his right eye. He experienced diplopia after removal of the patch from the operated eye 12 hour postoperatively due to esotropia in his left (unoperated eye. Diplopia was controlled using prism glasses and botulinum toxin A injections until PKP was performed in his left eye which resulted in restoration of stable fusion up to 3 years of follow up. CONCLUSION: Acute comitant esotropia may occur after loss of fusion due to ocular patching in a vulnerable patient. In this patient fusion was preserved with non-surgical methods until it was restored by surgical means.

  3. Simultaneous Penetrating Keratoplasty and Cataract Surgery

    Directory of Open Access Journals (Sweden)

    Mohammad-Ali Javadi

    2013-01-01

    Full Text Available Purpose: To determine the clinical outcomes of simultaneous penetrating keratoplasty (PK, cataract removal and intraocular lens implantation (triple procedure, and to compare the safety and efficacy of two different cataract extraction techniques during the course of PK. Methods: This retrospective comparative study was conducted on patients who had undergone a triple procedure. The technique of cataract extraction was either opensky extracapsular cataract extraction (ECCE or phacoemulsification (PE. In the ECCE group, the posterior chamber intraocular lens (PCIOL was implanted in the ciliary sulcus, while in the PE group PCIOLs were fixated within the capsular bag. Outcome measures included best spectacle corrected visual acuity (BSCVA, refractive results, graft clarity and complications. Results: Seventy-six eyes of 69 consecutive patients with mean age of 61.4±14.2 years were enrolled. Mean follow-up period was 61.4±37.2 months over which mean BSCVA was significantly improved from 1.40±0.68 to 0.44±0.33 LogMAR (P<0.001. Mean postoperative spherical equivalent refractive error was -2.13±3.02 D, which significantly differed from the target refraction (-0.73±0.29 D, P=0.004. At final follow-up, 89.5% of the corneal grafts remained clear. Conclusion: The triple procedure is a safe and effective approach to restore vision in patients with coexisting corneal pathologies and cataracts. However, unacceptable postoperative refractive error can be anticipated.

  4. Simultaneous Penetrating Keratoplasty and Cataract Surgery

    Science.gov (United States)

    Javadi, Mohammad-Ali; Feizi, Sepehr; Moein, Hamid-Reza

    2013-01-01

    Purpose To determine the clinical outcomes of simultaneous penetrating keratoplasty (PK), cataract removal and intraocular lens implantation (triple procedure), and to compare the safety and efficacy of two different cataract extraction techniques during the course of PK. Methods This retrospective comparative study was conducted on patients who had undergone a triple procedure. The technique of cataract extraction was either open- sky extracapsular cataract extraction (ECCE) or phacoemulsification (PE). In the ECCE group, the posterior chamber intraocular lens (PCIOL) was implanted in the ciliary sulcus, while in the PE group PCIOLs were fixated within the capsular bag. Outcome measures included best spectacle corrected visual acuity (BSCVA), refractive results, graft clarity and complications. Results Seventy-six eyes of 69 consecutive patients with mean age of 61.4±14.2 years were enrolled. Mean follow-up period was 61.4±37.2 months over which mean BSCVA was significantly improved from 1.40±0.68 to 0.44±0.33 LogMAR (P<0.001). Mean postoperative spherical equivalent refractive error was -2.13±3.02 D, which significantly differed from the target refraction (-0.73±0.29 D, P=0.004). At final follow-up, 89.5% of the corneal grafts remained clear. Conclusion The triple procedure is a safe and effective approach to restore vision in patients with coexisting corneal pathologies and cataracts. However, unacceptable postoperative refractive error can be anticipated. PMID:23825711

  5. A report of laser-assisted modified Widman flap for periodontal regeneration: Clinical and radiographic evaluation

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar Salaria

    2010-01-01

    Full Text Available Periodontitis is a relatively common disease. Various therapies have been recommended for its treatment which includes nonsurgical, antimicrobial, and surgical therapy. In recent years lasers have been used for all the three above-mentioned purposes. Lasers have been applied for hard and soft tissue debridement, contouring as well as the bacterial load reduction in the pocket. Here we present a case report of chronic periodontitis treated with the help of a new technique, laser-assisted modified Widman flap (LAMWF. The surgical procedure followed with a 980 nm diode laser has been described. The present case report resulted in significant pocket depth reduction, attachment gain, and radiographic evidence of bone fill. The laser-assisted modified Widman flap provided excellent results without complications and high patient as well as clinician satisfaction.

  6. A critical test for distorted wave theories: laser-assisted single ionization by ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Ciappina, Marcelo [Max-Planck-Institut fuer Physik Komplexer Systeme, Dresden (Germany); Madsen, Lars Bojer [Department of Physics and Astronomy, Univ. of Aarhus (Denmark)

    2008-07-01

    We study single ionization in laser-assisted high-energy non-relativistic ion-atom collisions and show that the low-energy angular differential electron spectrum may be enhanced significantly by a weak external field. With increasing the strength of the assisting field, the energy spectrum develops a plateau with a characteristic cut-off. In the plateau region we predict distinct multiphoton peaks separated by the photon-energy of the laser field. In the present laser-assisted continuum-distorted-wave eikonal-initial-state (LA-CDW-EIS) theory, this effect may be related to the dynamics in the two-body electron-projectile subsystem. The combined process where an electron is ionized by a heavy ion and subsequently moves in the laser field and under the influence of the Coulomb fields of the projectile and the target represents a stringent test for distorted wave theories.

  7. Indications for and techniques of keratoplasty at Vietnam National Institute of Ophthalmology

    Directory of Open Access Journals (Sweden)

    Pham Ngoc Dong

    2016-03-01

    Full Text Available AIM: To report the indications for and techniques of corneal transplantation at Vietnam National Institute of Ophthalmology (VNIO over a period of 12y (2002-2013. METHODS: Records of patients who had undergone corneal transplantation at VNIO from January 1, 2002 to January 1, 2014 were reviewed to determine the indication for and type of corneal transplant performed. Patient age, gender, indication for corneal transplantation and surgical technique were recorded and analyzed. RESULTS: Corneal transplantation were underwent in 1390 eyes of 1278 patients with a mean age of 44.9±18.1y during the period under review. The most common indication was infectious corneal ulcer (n=670; 48.2%, followed by corneal scar (n=333, 24.0%, corneal dystrophy (n=138, 9.9% and failed graft (n=112, 8.1%. Nearly all procedures performed were penetrating keratoplasty (n=1300, 93.5%, with a few lamellar keratoplasty procedures performed: lamellar keratoplasty (n=52, 3.7%, Descemet’s stripping automated endothelial keratoplasty (n=27, 1.9% and deep anterior lamellar keratoplasty (n=11, 0.8%. CONCLUSION: While the most common indication for keratoplasty was infectious keratitis, nearly all indications for corneal transplantation were managed with penetrating keratoplasty. However, lamellar keratoplasty techniques, including deep anterior lamellar keratoplasty and Descemet’s stripping automated endothelial keratoplasty, are being performed with increasing frequency for isolated stromal and endothelial disorders, respectively.

  8. Muon's anomalous magnetic moment effects on laser assisted Coulomb scattering process

    CERN Document Server

    Taj, S; Idrissi, M El; Attaourti, Y; Oufni, L

    2012-01-01

    Laser assisted Coulomb scattering by relativistic electron and heavy electron (muon) is studied by using Salamin waves (Salamin 1993) in the Weak Field Approximation (WFA). Both electron and muon are described by the Dirac equation, with the anomalous magnetic moment effects fully included. The generalization of this paper to heavy electron (muon) gives interesting insights as to how the mass affects the magnitude of the differential cross sections. No significant difference in the muon's DCS with and without AMM effects was detected.

  9. Microfabrication of Tungsten, Molybdenum and Tungsten Carbide Rods by Laser-Assisted CVD

    OpenAIRE

    Björklund, Kajsa

    2001-01-01

    Thin films of refractory metals and carbides have been studied extensively over many years because of their wide range of application. The two major techniques used are Chemical Vapour Deposition (CVD) and Physical Vapour Deposition (PVD). These can result in the deposition of two-dimensional blanket or patterned thin films. Laser-assisted Chemical Vapour Deposition (LCVD) can provide a maskless alternative for localised deposition in two and three dimensions. This thesis describes LCVD of mi...

  10. Secondary implantation of a double intraocular lens after penetrating keratoplasty.

    Science.gov (United States)

    Gayton, J L

    1998-02-01

    Penetrating keratoplasty (PKP) patients often have severe, visually disabling refractive errors. Astigmatism can be addressed by refractive surgery; however, correcting hyperopia is more problematic. Although pseudophakic PKP patients can have a lens exchange, it can be traumatic in this population. In this pseudophakic PKP patient, I added a second posterior chamber intraocular lens, correcting the hyperopia and resolving visual complaints.

  11. Ceratoplastia penetrante e glaucoma Penetrating keratoplasty and glaucoma

    Directory of Open Access Journals (Sweden)

    Márcio Eulálio Barreto Soares

    2007-08-01

    Full Text Available O objetivo deste artigo é discutir os conhecimentos atuais sobre a abordagem clínica e terapêutica da ceratoplastia penetrante e do glaucoma a ela associado.The aim of this article is to make a review about glaucoma associated with penetrating keratoplasty, describing since its incidence and risk factors until the different options for treatment.

  12. MERSILENE (POLYESTER), A NEW SUTURE FOR PENETRATING KERATOPLASTY

    NARCIS (Netherlands)

    RAMSELAAR, JAM; BEEKHUIS, WH; RIJNEVELD, WJ; VANANDEL, MV; DIJK, F; JONGEBLOED, WL

    1992-01-01

    Mersilene (polyester monofilament) seems to be suitable for penetrating keratoplasty because it is strong, shows no degradation by ultraviolet light, is insoluble, so that it can be left in situ, and offers the possibility of regulating postoperative astigmatism by suture adjustment. In 12 patients

  13. Systematic review comparing penetrating keratoplasty and deep anterior lamellar keratoplasty for management of keratoconus.

    Science.gov (United States)

    Henein, Christin; Nanavaty, Mayank A

    2017-02-01

    Perception of reduced incidence of graft rejection after deep anterior lamellar keratoplasty (DALK) has attracted many surgeons towards this technique in keratoconus. This review aims to compare the visual, refractive and graft outcomes after penetrating keratoplasty (PK) and DALK for keratoconus. Electronic searches of PubMed, MEDLINE, EMBASE, Latin American and Caribbean Health Sciences Literature database (LILACS), metaRegister of Controlled Trials (mRCT), ClinicalTrial.gov and the WHO International Clinical Trials Registry Platform (ICTRP) were performed. We included randomized control trials (RCTs) and comparative studies to assess primary and secondary outcomes after PK and DALK in eyes with keratoconus. Primary outcome was best-corrected visual acuity (BCVA) LogMAR at ≥6 months. Secondary outcomes included number of patients with BCVA≥0 LogMAR, uncorrected visual acuity (UCVA) LogMAR, spherical equivalent (SE), refractive and keratometric astigmatism, endothelial cell density (ECD) cell/mm(2), graft rejection and graft survival. Eighteen studies (including 2 RCTs) compared DALK (965 eyes) and PK (2402 eyes) for keratoconus. There was strong evidence through RCTs suggesting better LogMAR BCVA at ≥6 months and better LogMAR UCVA with PK; reduced refractive astigmatism and rejection with DALK and no difference in SE and keratometric astigmatism. Moreover, there was weak evidence to suggest better BCVA≥0 LogMAR after PK and no difference in ECD between the two techniques. Despite the popularity of DALK amongst corneal surgeons for keratoconus, there is a paucity of high quality RCTs. The existing limited evidence confirms reduced rejection and refractive astigmatism with DALK but better visual outcomes with PK. Internationally agreed data sets and follow-up protocol are warranted. Copyright © 2016 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  14. Effects of laser power during laser assisted cold spraying of Al-12wt%Si on stainless steel

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2012-10-01

    Full Text Available This study seeks to demonstrate Laser Assisted Cold Spraying (LACS) by depositing Al-12wt%Si on stainless steel substrate. LACS is a newly designed, assembled and commissioned technology in the CSIR, laser materials processing laboratories...

  15. Laser-assisted drug delivery in dermatology: from animal models to clinical practice.

    Science.gov (United States)

    Ali, Faisal R; Al-Niaimi, Firas

    2016-02-01

    Topical medicaments are the mainstay of the dermatologists' therapeutic arsenal. Laser-assisted drug delivery enhances the ability of topically applied medicaments to penetrate the skin. We discuss the mechanisms of laser-assisted drug delivery and animal models that have informed clinical practice. We review clinical studies that have employed laser-assisted drug delivery for a range of indications to date including non-melanoma skin cancer, vitiligo, scarring, vaccination, local anaesthesia, analgesia, viral warts, infantile haemangiomas and cosmetic uses. Studies thus far suggest that laser pre-treatment improves transepidermal absorption of topical agents and allows for a much deeper penetration of drugs than is possible with topical medicaments alone. This may allow more efficacious action of current treatments, such that conventional duration of treatment can be shortened or lower concentrations of active agents be used, potentially obviating side effects of treatment. The prospect of using laser technologies to facilitate transdermal vaccination and as an adjunct for inflammatory dermatoses and cosmetic indications remains in its infancy. As larger trials are published, involving greater numbers of patients and utilising various laser and topical medicament parameters, we will enhance our understanding of this nascent modality of treatment delivery.

  16. Pulse laser assisted MOVPE for InGaN with high indium content

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, Norihito [Technical Development and Engineering Center, Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama 235-8501 (Japan); Dept. of Applied Chemistry, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Hida, Kennosuke; Kangawa, Yoshihiro; Kumagai, Yoshinao; Koukitu, Akinori [Dept. of Applied Chemistry, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2004-09-01

    In{sub 0.53}Ga{sub 0.47}N film was grown at 600 C by Nd:YAG pulse laser assisted MOVPE. The optical and structural properties of the film were compared with that grown without laser assistance at the same condition. The results of XRD measurements showed that the crystallinity of the film grown with laser was better than that of the one grown without laser. The surface morphology and cross-sectional SEM image of the film grown with laser revealed that there were no In droplets on the film. The band-edge emission of the film grown with laser at room temperature and 77 K was observed at 840 nm. The results of micro-Raman measurement showed that the film grown with laser had better crystalline structure than that of the film grown without laser and the radiative recombination which contributed to photoluminescence mainly occurred at In{sub 0.53}Ga{sub 0.47}N region. Those results imply that pulse laser enhances the surface migration and reaction of elements in spite of low-growth temperature. We suggest that pulse laser assisted technique is effective for low-temperature growth of InGaN with high indium content. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Pulse laser assisted MOVPE for InGaN with high indium content

    Science.gov (United States)

    Kawaguchi, Norihito; Hida, Ken-Nosuke; Kangawa, Yoshihiro; Kumagai, Yoshinao; Koukitu, Akinori

    2004-09-01

    In0.53Ga0.47N film was grown at 600 °C by Nd:YAG pulse laser assisted MOVPE. The optical and structural properties of the film were compared with that grown without laser assistance at the same condition. The results of XRD measurements showed that the crystallinity of the film grown with laser was better than that of the one grown without laser. The surface morphology and cross-sectional SEM image of the film grown with laser revealed that there were no In droplets on the film. The band-edge emission of the film grown with laser at room temperature and 77 K was observed at 840 nm. The results of micro-Raman measurement showed that the film grown with laser had better crystalline structure than that of the film grown without laser and the radiative recombination which contributed to photoluminescence mainly occurred at In0.53Ga0.47N region. Those results imply that pulse laser enhances the surface migration and reaction of elements in spite of low-growth temperature. We suggest that pulse laser assisted technique is effective for low-temperature growth of InGaN with high indium content.

  18. CdS thin films prepared by laser assisted chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, L.V.; Mendivil, M.I.; Garcia Guillen, G.; Aguilar Martinez, J.A. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Krishnan, B. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); CIIDIT – Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Avellaneda, D.; Castillo, G.A.; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); CIIDIT – Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2015-05-01

    Highlights: • CdS thin films by conventional CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • Improved dark conductivity and good photocurrent response for the LACBD CdS. - Abstract: In this work, we report the preparation and characterization of CdS thin films by laser assisted chemical bath deposition (LACBD). CdS thin films were prepared from a chemical bath containing cadmium chloride, triethanolamine, ammonium hydroxide and thiourea under various deposition conditions. The thin films were deposited by in situ irradiation of the bath using a continuous laser of wavelength 532 nm, varying the power density. The thin films obtained during deposition of 10, 20 and 30 min were analyzed. The changes in morphology, structure, composition, optical and electrical properties of the CdS thin films due to in situ irradiation of the bath were analyzed by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–vis spectroscopy. The thin films obtained by LACBD were nanocrystalline, photoconductive and presented interesting morphologies. The results showed that LACBD is an effective synthesis technique to obtain nanocrystalline CdS thin films having good optoelectronic properties.

  19. Contrast sensitivity in deep anterior lamellar keratoplasty versus penetrating keratoplasty Sensibilidade ao contraste entre transplante lamelar anterior profundo e transplante penetrante de córnea

    Directory of Open Access Journals (Sweden)

    Carlos Anchieta Castro Cardoso da Silva

    2007-01-01

    Full Text Available PURPOSE: To compare the measurements of contrast sensitivity at a distance in patients submitted to penetrating keratoplasty versus patients submitted to deep anterior lamellar keratoplasty for keratoconus treatment. METHODS: Contrast sensitivity of 15 subjects submitted to penetrating keratoplasty and 15 subjects submitted to deep anterior lamellar keratoplasty have been analyzed through the Functional Acuity Contrast Test (F.A.C.T® 301. RESULTS: There was no statistically significant difference between the measurements for penetrating keratoplasty and deep anterior lamellar keratoplasty. CONCLUSION: Contrast sensitivity was similar among the subjects submitted to penetrating keratoplasty and to deep anterior lamellar keratoplasty for keratoconus treatment.OBJETIVO: Comparar as medidas de sensibilidade ao contraste à distância entre pacientes submetidos à ceratoplastia penetrante e pacientes submetidos à ceratoplastia lamelar anterior profunda para tratamento do ceratocone. MÉTODOS: Sensibilidades ao contraste de 15 pacientes submetidos à ceratoplastia penetrante e de 15 pacientes submetidos à ceratoplastia lamelar anterior profunda foram analisadas através do Functional Acuity Contrast Test (F.A.C.T® 301. RESULTADOS: Não existiu diferença estatisticamente significante entre as medidas em ceratoplastia penetrante e ceratoplastia lamelar anterior profunda. CONCLUSÃO: Sensibilidade ao contraste foi similar entre os pacientes submetidos à ceratoplastia penetrante e à ceratoplastia lamelar anterior profunda para tratamento do ceratocone.

  20. Profitability analysis of a femtosecond laser system for cataract surgery using a fuzzy logic approach.

    Science.gov (United States)

    Trigueros, José Antonio; Piñero, David P; Ismail, Mahmoud M

    2016-01-01

    To define the financial and management conditions required to introduce a femtosecond laser system for cataract surgery in a clinic using a fuzzy logic approach. In the simulation performed in the current study, the costs associated to the acquisition and use of a commercially available femtosecond laser platform for cataract surgery (VICTUS, TECHNOLAS Perfect Vision GmbH, Bausch & Lomb, Munich, Germany) during a period of 5y were considered. A sensitivity analysis was performed considering such costs and the countable amortization of the system during this 5y period. Furthermore, a fuzzy logic analysis was used to obtain an estimation of the money income associated to each femtosecond laser-assisted cataract surgery (G). According to the sensitivity analysis, the femtosecond laser system under evaluation can be profitable if 1400 cataract surgeries are performed per year and if each surgery can be invoiced more than $500. In contrast, the fuzzy logic analysis confirmed that the patient had to pay more per surgery, between $661.8 and $667.4 per surgery, without considering the cost of the intraocular lens (IOL). A profitability of femtosecond laser systems for cataract surgery can be obtained after a detailed financial analysis, especially in those centers with large volumes of patients. The cost of the surgery for patients should be adapted to the real flow of patients with the ability of paying a reasonable range of cost.

  1. Combining femtosecond laser ablation and diode laser welding in lamellar and endothelial corneal transplants

    Science.gov (United States)

    Pini, Roberto; Rossi, Francesca; Matteini, Paolo; Ratto, Fulvio; Menabuoni, Luca; Lenzetti, Ivo; Yoo, Sonia H.; Parel, Jean-Marie

    2008-02-01

    Based on our previous clinical experiences in minimally invasive diode laser-induced welding of corneal tissue in penetrating keratoplasty (PK), i.e. full-thickness transplant of the cornea, we combined this technique with the use of a femtosecond laser for applications in lamellar (LK) and endothelial (EK) keratoplasty. In LK, the femtosecond laser was used to prepare donor button and recipient corneal bed; the wound edges were stained with a water solution of Indocyanine Green (ICG) and then irradiated with a diode laser emitting in CW mode to induce stromal welding. Intraoperatory observations and follow-up results up to 6 months indicated the formation of a smooth stromal interface, total absence of edema as well as inflammation, and reduction of post-operative astigmatism, as compared with conventional suturing procedures. In EK the femtosecond laser was used for the preparation of a 100 μm thick, 8.5mm diameter donor corneal endothelium flap. The flap stromal side was stained with ICG. After stripping the recipient Descemet's membrane and endothelium, the donor flap was positioned in the anterior chamber on the inner face of the cornea by an air bubble and secured to the recipient cornea by diode laser pulses delivered by means of a fiberoptic contact probe introduced in the anterior chamber, which produced welding spots of 200 μm diameter. Femtosecond laser sculpturing of the donor cornea provided lamellar and endothelial flaps of preset and constant thickness. Diode laserinduced welding showed a unique potential to permanently secure the donor flap in place, avoiding postoperative displacement and inflammation reaction.

  2. Diode laser-assisted transcanalicular dacryocystorhinostomy: the effect of age on the results

    Directory of Open Access Journals (Sweden)

    Fahrettin Akay

    2015-06-01

    Full Text Available ABSTRACT Purpose: The aim of this study was to explore the effect of age on the success of transcanalicular diode laser-assisted dacryocystorhinostomy (TCDCR. Methods: Seventy patients (70 eyes who underwent transcanalicular diode laser-assisted dacryocystorhinostomy for the treatment of nasolacrimal duct obstruction as a primary surgery were included in this retrospective, nonrandomized study. The patients were divided into two groups according to age. Mean ages were 21.3 ± 3.3 in group 1 and 60.3 ± 7.3 in group 2. The records of the 3-, 6-, and 12-month follow-up examinations were evaluated, and the anatomical and functional outcomes were noted. Functional success was defined as the absence of epiphora as indicated by the patient. Anatomical success was determined as patency of the neo-ostium with irrigation. Results: At the 3-month follow-up, 67% cases in group 1 showed anatomical success and 52% showed functional success; in group 2, the rates were 100% and 92%, respectively. Functional and anatomical success rates were the same for both the 6- and 12-month visits; 46% in group 1 and 76% in group 2. The results in group 2 were significantly better at all three follow-up visits (p<0.05. Conclusions: This study clearly showed that the older patients experienced better transcanalicular diode laser-assisted dacryocystorhinostomy results than the younger patients. The diminished inflammatory response in the older population may be a possible contributing factor to these results.

  3. Selective tuning of high-Q silicon photonic crystal nanocavities via laser-assisted local oxidation

    CERN Document Server

    Chen, Charlton J; Gu, Tingyi; McMillan, James F; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee; Wong, Chee Wei

    2011-01-01

    We examine the cavity resonance tuning of high-Q silicon photonic crystal heterostructures by localized laser-assisted thermal oxidation using a 532 nm continuous wave laser focused to a 2.5 mm radius spot-size. The total shift is consistent with the parabolic rate law. A tuning range of up to 8.7 nm is achieved with ~ 30 mW laser powers. Over this tuning range, the cavity Q decreases from 3.2\\times10^5 to 1.2\\times10^5. Numerical simulations model the temperature distributions in the silicon photonic crystal membrane and the cavity resonance shift from oxidation.

  4. Management of Gingival Overgrowth in a Cardiac Transplant Patient Using Laser-Assisted Gingivectomy/Gingivoplasty.

    Science.gov (United States)

    Maddi, Abhiram; Alluri, Leela Subhashini; Ciancio, Sebastian G

    2015-07-01

    Drug-induced gingival overgrowth (DIGO) is an oral clinical manifestation associated with certain medications such as immunosuppressants that are administered to organ transplant patients to prevent graft rejection. In patients with cardiac transplants, management of DIGO is critical. In such patients, plaque biofilm accumulation at the gingival interface might be detrimental as it may lead to transient bacteremia as well as systemic inflammation resulting in thromboembolic events. This case report describes the management of DIGO in a cardiac transplant recipient by change of immunosuppressant medication, non-surgical periodontal therapy and laser-assisted gingivectomy.

  5. Experimental and theoretical evaluation of the laser-assisted machining of silicon nitride

    Science.gov (United States)

    Rozzi, Jay Christopher

    This study focused on the experimental and theoretical evaluation of the laser assisted machining (LAM) of silicon nitride ceramics. A laser assisted machining facility was constructed whose main components consist of a COsb2 laser and a CNC lathe. Surface temperature histories were first measured and compared to a transient, three-dimensional numerical simulation for a rotating silicon nitride workpiece heated by a translating laser for ranges of the workpiece rotational and laser-translation speeds, as well as the laser beam diameter and power. Excellent agreement was obtained between the experimental and predicted temperature histories. Laser assisted machining experiments on silicon nitride ceramic workpieces were completed for a wide range of operating conditions. Data for cutting forces and surface temperature histories illustrated that the lower bound for the avoidance of cutting tool and/or workpiece fracture for LAM is defined by the YSiAlON glass transition temperature (920-970sp°C). As temperatures near the cutting tool increase to values above the glass transition temperature range, the glassy phase softened, facilitating plastic deformation and, correspondingly, the production of semi-continuous or continuous chips. The silicon nitride machined workpiece surface roughness (Rsb{a}=0.39\\ mum) for LAM at the nominal operating condition was nearly equivalent to a value associated with the grinding of silicon nitride using a diamond wheel (Rsb{a}=0.2\\ mum). By examining the machined surfaces and chips, it was shown that LAM does not produce detectable sub-surface cracking or significant silicon nitride microstructure alteration, respectively. A transient, three-dimensional numerical heat transfer model of laser assisted machining was constructed, which includes a preheat phase and material removal, with the associated changes in the workplace geometry. Excellent agreement was obtained between the measured and predicted temperature histories. The strong

  6. The impact of treatment density and molecular weight for fractional laser-assisted drug delivery

    DEFF Research Database (Denmark)

    Haak, Christina S; Bhayana, Brijesh; Farinelli, William A

    2012-01-01

    Ablative fractional lasers (AFXL) facilitate uptake of topically applied drugs by creating narrow open micro-channels into the skin, but there is limited information on optimal laser settings for delivery of specific molecules. The objective of this study was to investigate the impact of laser tr...... treatment density (% of skin occupied by channels) and molecular weight (MW) for fractional CO(2) laser-assisted drug delivery. AFXL substantially increased intra- and transcutaneous delivery of polyethylene glycols (PEGs) in a MW range from 240 to 4300 Da (Nuclear Magnetic Resonance, p...

  7. Laser and optical system for laser assisted hydrogen ion beam stripping at SNS

    Science.gov (United States)

    Liu, Y.; Rakhman, A.; Menshov, A.; Webster, A.; Gorlov, T.; Aleksandrov, A.; Cousineau, S.

    2017-03-01

    Recently, a high-efficiency laser assisted hydrogen ion (H-) beam stripping was successfully carried out in the Spallation Neutron Source (SNS) accelerator. The experiment was not only an important step toward foil-less H- stripping for charge exchange injection, it also set up a first example of using megawatt ultraviolet (UV) laser source in an operational high power proton accelerator facility. This paper reports in detail the design, installation, and commissioning result of a macro-pulsed multi-megawatt UV laser system and laser beam transport line for the laser stripping experiment.

  8. Tool life of diamond inserts after laser assisted turning of cemented carbides

    Directory of Open Access Journals (Sweden)

    Kieruj Piotr

    2017-01-01

    Full Text Available The paper presents results and discussion on parameters influence on tool life when turning laser cladded cemented carbides under laser assisted machining (LAM conditions. The layers are known as Technolase 30S. This material is widely recognized as hard-to-cut. The experimental investigation was carried out with diamond inserts. The laser power density, feed rate and laser scanning speed were analysed. Flank wear (VBc indicator was measured and cutting tool life was calculated. It was proved that Technolase 30S can be machined with LAM technology. The laser enhanced turning is more efficient than conventional turning and grinding.

  9. Laser-assisted direct ink writing of planar and 3D metal architectures

    Science.gov (United States)

    Skylar-Scott, Mark A.; Gunasekaran, Suman; Lewis, Jennifer A.

    2016-05-01

    The ability to pattern planar and freestanding 3D metallic architectures at the microscale would enable myriad applications, including flexible electronics, displays, sensors, and electrically small antennas. A 3D printing method is introduced that combines direct ink writing with a focused laser that locally anneals printed metallic features “on-the-fly.” To optimize the nozzle-to-laser separation distance, the heat transfer along the printed silver wire is modeled as a function of printing speed, laser intensity, and pulse duration. Laser-assisted direct ink writing is used to pattern highly conductive, ductile metallic interconnects, springs, and freestanding spiral architectures on flexible and rigid substrates.

  10. Laser-assisted direct ink writing of planar and 3D metal architectures.

    Science.gov (United States)

    Skylar-Scott, Mark A; Gunasekaran, Suman; Lewis, Jennifer A

    2016-05-31

    The ability to pattern planar and freestanding 3D metallic architectures at the microscale would enable myriad applications, including flexible electronics, displays, sensors, and electrically small antennas. A 3D printing method is introduced that combines direct ink writing with a focused laser that locally anneals printed metallic features "on-the-fly." To optimize the nozzle-to-laser separation distance, the heat transfer along the printed silver wire is modeled as a function of printing speed, laser intensity, and pulse duration. Laser-assisted direct ink writing is used to pattern highly conductive, ductile metallic interconnects, springs, and freestanding spiral architectures on flexible and rigid substrates.

  11. Heat transfer model of semi-transparent ceramics undergoing laser-assisted machining

    Energy Technology Data Exchange (ETDEWEB)

    Pfefferkorn, F.E. [University of Wisconsin-Madison (United States). Department of Mechanical Engineering; Incropera, F.P. [University of Notre Dame, IN (United States). College of Engineering; Yung C. Shin [Purdue University, West Lafayette, IN (United States). School of Mechanical Engineering

    2005-05-01

    A three-dimensional, unsteady heat transfer model has been developed for predicting the temperature field in partially-stabilized zirconia (PSZ) undergoing laser-assisted machining. The semi-transparent PSZ is treated as optically thick within a spectral band from approximately 0.5 to 8 {mu}m. After comparing the diffusion approximation and the discrete ordinates method for predicting internal radiative transfer, suitability of the diffusion approximation is established from a comparison of model predictions with surface temperature measurements. The temperature predictions are in good agreement with measured values during machining. Parametric calculations reveal that laser power and feedrate have the greatest effect on machining temperatures. (author)

  12. Studies on surface pitting during laser assisted removal of translucent ellipsoidal particulates from metallic substrates

    Science.gov (United States)

    Sugathan, Bijoy; Nilaya, J. Padma; Pillai, V. P. Mahadevan; Biswas, D. J.

    2017-04-01

    We report on the manifestation of field enhanced surface absorption during laser assisted removal of translucent particulates of ellipsoidal geometry from a metallic substrate surface. The surface pitting caused due to this effect has been experimentally probed as a function of the ratio of minor to major axis of the ellipsoid and the behavioral trend has been theoretically interpreted by invoking the principle of geometrical optics. The study also includes the effect of fluence and wavelength of the incident coherent radiation on the surface pitting. Probing of the surface topography has helped gain insight into the formation of multiple pits by a single particulate following its removal post laser exposure.

  13. Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy

    OpenAIRE

    Sabina Luisa Campanelli; Giuseppe Casalino; Caterina Casavola; Vincenzo Moramarco

    2013-01-01

    Friction Stir Welding (FSW) is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW) is a combination in which the FSW is the dominant welding process and the laser pre-heats the we...

  14. Effects of Volkov functions in laser-assisted electron momentum spectroscopy

    Science.gov (United States)

    Bulychev, Andrey A.; Kouzakov, Konstantin A.; Popov, Yuri V.

    2013-02-01

    We consider theoretically an electron-impact ionization process at high impact energy and large momentum transfer in the presence of laser radiation. The target is modeled as an electron bound by a harmonic potential. Dressing of the target state by the laser field is treated exactly. Laser-assisted differential cross sections are calculated using either Volkov functions or plane waves for incoming and outgoing electrons. It is shown that even in the case of the low-frequency and weak-intensity laser radiation the effect of the field on these electrons can dramatically influence the shape of the cross sections.

  15. An Investigation of Laser Assisted Machining of Al_2O_3 Particle Reinforced Aluminum Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Al 2O 3 particles reinforced aluminum matrix composite (Al 2O 3p/Al) are more and more widely used for their excellent physical and chemical properties. However, their poor machinability leads to severe tool wear and bad machined surface. In this paper laser assisted machining is adopted in machining Al 2O 3p/Al composite and good result was obtained. The result of experiment shows in machining Al 2O 3p/Al composites the cutting force is reduced in 30%~50%, the tool wear is reduced in 20%~30% an...

  16. Laser-assisted field evaporation of metal oxides: A time-dependent density functional theory study

    Science.gov (United States)

    Xia, Yu; Li, Zhibing

    2016-11-01

    To understand laser-assisted field evaporation of semiconductors and insulators at the microscopic level, we study the time evolution of the electronic and atomic structure of a MgO cluster in high electrostatic fields subjected to strong laser pulses. We find that the critical laser intensity for evaporation decreases linearly as the electrostatic field strength increases. The optical absorption enhancement in high electrostatic field is confirmed by the redshift of the optical absorption spectra, the reduction of the energy gap, and the increase of the absorption cross section.

  17. Laser-assisted metal spinning for an efficient and flexible processing of challenging materials

    Science.gov (United States)

    Brummer, C.; Eck, S.; Marsoner, S.; Arntz, K.; Klocke, F.

    2016-03-01

    The demand for components made from high performance materials like titanium or nickel-based alloys as well as strain-hardening stainless steel is steadily increasing. However, conventional forming operations conducted on these materials are generally very laborious and time-consuming. This is where the limitations of metal spinning also become apparent. Using a laser to apply heat localized to the forming zone during metal spinning facilitates to enhance the formability of a material. In order to analyse the potential of the new manufacturing process, experimental investigations on laser-assisted shear forming and multi-pass metal spinning have been performed with austenitic stainless steel X5CrNi18-10, nickel-based alloy Inconel 718 and titanium grade 2. It could be demonstrated that the formability of these materials can be enhanced by laser-assistance. Besides the resulting enhancement of forming limits for metal spinning of challenging materials, the forming forces were reduced and the product quality was improved significantly.

  18. Analysis of plasma characteristics and conductive mechanism of laser assisted pulsed arc welding

    Science.gov (United States)

    Liu, Shuangyu; Chen, Shixian; Wang, Qinghua; Li, Yanqing; Zhang, Hong; Ding, Hongtao

    2017-05-01

    This study aims to investigate the arc plasma shape and the spectral characteristics during the laser assisted pulsed arc welding process. The arc plasma shape was synchronously observed using a high speed camera, and the emission spectrum of plasma was obtained by spectrometer. The well-known Boltzmann plot method and Stark broadening were used to calculate the electron temperature and density respectively. The conductive mechanism of arc ignition in laser assisted arc hybrid welding was investigated, and it was found that the plasma current moved to the arc anode under the action of electric field. Thus, a significant parabolic channel was formed between the keyhole and the wire tip. This channel became the main method of energy transformation between the arc and the molten pool. The calculation results of plasma resistivity show that the laser plasma has low resistivity as the starting point of conductive channel formation. When the laser pulse duration increases, the intensity of the plasma radiation spectrum and the plasma electron density will increase, and the electron temperature will decrease.

  19. Laser assisted micro-welding of ultra-thin glass wafers

    Science.gov (United States)

    Hevonkorpi, V.; Lundén, H.; Määttänen, A.

    2016-03-01

    The use of glass in semiconductor industry has been growing during the past years and the grow is estimated to continue and accelerate considerably during the coming years. For efficient manufacturing, especially when using ultra-thin wafers, novel bonding technologies are needed. In this paper, a laser assisted additive free glass-glass welding technology is presented. Furthermore, the use of laser assisted welding to manufacture hermetic packages for optical components is investigated. The reliability and robustness of the weld and the process is verified by damp heat (85 °C at 85% RH) testing. A large quantity, one hundred samples, was tested to define the repeatability of the welding process. D263T, a glass type commonly used in manufacturing consumer products, was selected. Glass-glass welding proved to be a reliable bonding method offering a non-outgassing, room temperature bonding. In addition, it was verified that the weld is hermetic having a good resistance to high temperature and moisture conditions. No changes in the welding seams were observed during or after damp heat testing.

  20. Dispensing pico to nanolitre of a natural hydrogel by laser-assisted bioprinting

    Directory of Open Access Journals (Sweden)

    Deiwick Andrea

    2011-03-01

    Full Text Available Abstract Background Laser-assisted bioprinting of multi-cellular replicates in accordance with CAD blueprint may substantially improve our understandings of fundamental aspects of 3 D cell-cell and cell-matrix interactions in vitro. For predictable printing results, a profound knowledge about effects of different processing parameters is essential for realisation of 3 D cell models with well-defined cell densities. Methods Time-resolved imaging of the hydrogel jet dynamics and quantitative assessment of the dependence of printed droplet diameter on the process characteristics were conducted. Results The existence of a counterjet was visualised, proving the bubble collapsing theory for the jet formation. Furthermore, by adjusting the viscosity and height of the applied hydrogel layer in combination with different laser pulse energies, the printing of volumes in the range of 10 to 7000 picolitres was demonstrated. Additionally, the relationship between the viscosity and the layer thickness at different laser pulse energies on the printed droplet volume was identified. Conclusions These findings are essential for the advancement of laser-assisted bioprinting by enabling predictable printing results and the integration of computational methods in the generation of 3 D multi-cellular constructs.

  1. System technology for laser-assisted milling with tool integrated optics

    Science.gov (United States)

    Hermani, Jan-Patrick; Emonts, Michael; Brecher, Christian

    2013-02-01

    High strength metal alloys and ceramics offer a huge potential for increased efficiency (e. g. in engine components for aerospace or components for gas turbines). However, mass application is still hampered by cost- and time-consuming end-machining due to long processing times and high tool wear. Laser-induced heating shortly before machining can reduce the material strength and improve machinability significantly. The Fraunhofer IPT has developed and successfully realized a new approach for laser-assisted milling with spindle and tool integrated, co-rotating optics. The novel optical system inside the tool consists of one deflection prism to position the laser spot in front of the cutting insert and one focusing lens. Using a fiber laser with high beam quality the laser spot diameter can be precisely adjusted to the chip size. A high dynamic adaption of the laser power signal according to the engagement condition of the cutting tool was realized in order not to irradiate already machined work piece material. During the tool engagement the laser power is controlled in proportion to the current material removal rate, which has to be calculated continuously. The needed geometric values are generated by a CAD/CAM program and converted into a laser power signal by a real-time controller. The developed milling tool with integrated optics and the algorithm for laser power control enable a multi-axis laser-assisted machining of complex parts.

  2. Five-year comparative study on conventional and laser-assisted therapy of periimplantitis and periodontitis

    Science.gov (United States)

    Bach, Georg; Neckel, Claus P.

    2000-03-01

    Numerous groups have recommended the use of the diode laser to decontaminate infected root and implant surfaces. The aim of this study was to show the outcome after laser assisted and conventional therapy of periimplantitis and periodontitis administering approved treatment protocols. Between 1994 and 1999 a total of 50 patients with periimplantitis (20) and periodontitis (30) were treated in two groups each. Clinical, microbiological and radiographic evaluation was performed before and 6, 12, 24, 36, 48 and 60 months after treatment. In addition to the conventional treatment protocol, flap surgery, the tooth or implant surface was decontaminated with a 810 nm diode laser using 1 Watt output for 20 sec (CW mode). All accessible surfaces were decontaminated at the follow up dates. In the periimplantitis group recurrence of the marker bacteria was higher and faster over time for the conventionally operated patients. Also the clinical and radiographic reevaluation showed significantly better results. The laser group of the periodontitis patients also showed significantly better outcome in terms of clinical evaluation, microbiological counts, radiographic evaluation and tooth loss. In comparison to other long term studies our results for the conventional therapy were adequate, the laser assisted therapy brought up significantly better and reproducible results.

  3. An experimental investigation of pulsed laser-assisted machining of AISI 52100 steel

    Science.gov (United States)

    Panjehpour, Afshin; Soleymani Yazdi, Mohammad R.; Shoja-Razavi, Reza

    2014-11-01

    Grinding and hard turning are widely used for machining of hardened bearing steel parts. Laser-assisted machining (LAM) has emerged as an efficient alternative to grinding and hard turning for hardened steel parts. In most cases, continuous-wave lasers were used as a heat source to cause localized heating prior to material removal by a cutting tool. In this study, an experimental investigation of pulsed laser-assisted machining of AISI 52100 bearing steel was conducted. The effects of process parameters (i.e., laser mean power, pulse frequency, pulse energy, cutting speed and feed rate) on state variables (i.e., material removal temperature, specific cutting energy, surface roughness, microstructure, tool wear and chip formation) were investigated. At laser mean power of 425 W with frequency of 120 Hz and cutting speed of 70 m/min, the benefit of LAM was shown by 25% decrease in specific cutting energy and 18% improvement in surface roughness, as compared to those of the conventional machining. It was shown that at constant laser power, the increase of laser pulse energy causes the rapid increase in tool wear rate. Pulsed laser allowed efficient control of surface temperature and heat penetration in material removal region. Examination of the machined subsurface microstructure and microhardness profiles showed no change under LAM and conventional machining. Continuous chips with more uniform plastic deformation were produced in LAM.

  4. Laser-assisted machining process simulation for precision mould/die manufacturing

    Directory of Open Access Journals (Sweden)

    Zeng Quanren

    2015-01-01

    Full Text Available Laser-assisted machining (LAM is a kind of thermally assisted manufacturing process which preheats workpiece material with a highly-localized laser beam and then is followed by a conventional machining operation. It could greatly improve the machinability and gives better machining quality, especially suitable for hard-to-cut materials such as superalloys, tool steels. For manufacturing the high-precision moulds/dies that could fabricate micro and precision components, the thermal assistance at the local cutting zone, will help to lower the cutting force and consequently improve the internal surface quality of the machined moulds/dies. In this paper, a numerical study of the laser-assisted cutting of plastic mould steel NAK80 is reported. The simulation of LAM of NAK80 is realized by combining two procedures: simulation of moving laser heat source applied on the local surface of workpiece which causes the corresponding temperature field arise and material soften, and simulation of the subsequent cutting processes. This research will offer the die/mould manufacturers a more efficient planning tool for the fabrication of the micro, precision dies/moulds of high surface quality, and hence, for forming the high-quality micro components as well as for longer die/mould life.

  5. [The treatment of otosclerosis using laser assisted stapedotomy with mini incision in external auditory meatus].

    Science.gov (United States)

    Hao, Xinping; Chen, Shubin; Yu, Zilong; Liang, Fenghe; Li, Yongxin

    2016-03-01

    To investigate the feasibility of the treatment of otosclerosis using laser stapedotomy with mini incision in the external auditory meatus. Thirteen patients(15 ears) with otosclerosis evidence on clinic history. They were all operated using the laser assisted stapedotomy by mini incision in external auditory meatus because of the wide straight canal. Laser resection the tendo musculistapedius and anterior and postrior arch, breaking the articulatioincudostapedia, removing the stapes superstructure, making a hole of 6mm diameter in the rear of stapes footplate by laser drilling, implanting the corresponding length Piston artificial ossicle. All the surgeries were successful and the operation time was about one hour. There was only one patient manifested vertigo and nausea after the operation. But the symptoms improved three days later after the expectant treatment. All the incisions were healed in the externals. There was significant difference between the preoperative and postoperative PTA. The air conduct improved in every frequent and the bone conduct improved in 1 kHz, 2 kHz and 4 kHz. Laser assisted stapedotomy by mini incision in the external auditory meatus in patients having wide straight canal with otosclerosis can shorten the operation time, minimize the tissue damage, fasten the healing of the incision and reduce the complications postoperatively. In addition, the mini incision is beauty and easy to nurse.

  6. Rescue of Primary Incomplete Microkeratome Flap with Secondary Femtosecond Laser Flap in LASIK

    Directory of Open Access Journals (Sweden)

    E. A. Razgulyaeva

    2014-01-01

    Full Text Available For laser-assisted in situ keratomileusis (LASIK retreatments with a previous unsuccessful mechanical microkeratome-assisted surgery, some surgical protocols have been described as feasible, such as relifting of the flap or the creation of a new flap and even the change to a surface ablation procedure (photorefractive keratectomy (PRK. This case shows the use of femtosecond technology for the creation of a secondary flap to perform LASIK in a cornea with a primary incomplete flap obtained with a mechanical microkeratome. As we were unable to characterize the interface of the first partial lamellar cut, a thick flap was planned and created using a femtosecond laser platform. As the primary cut was very thick in the nasal quadrant, a piece of loose corneal tissue appeared during flap lifting which was fitted in its position and not removed. Despite this condition and considering the regularity of the new femtosecond laser cut, the treatment was uneventful. This case report shows the relevance of a detailed corneal analysis with an advanced imaging technique before performing a secondary flap in a cornea with a primary incomplete flap. The femtosecond laser technology seems to be an excellent tool to manage such cases successfully.

  7. Laser assisted conical spin forming of dual phase automotive steel. Experimental demonstration of work hardening reduction and forming limit extension

    Science.gov (United States)

    Romero, P.; Otero, N.; Cabrera, J. M.; Masagué, D.

    Laser Assisted Spin Forming is investigated for improving the poor formability of Advanced High Strength Steel DP-800 and Aeronautic Grade Titanium alloy, with minor or no change in microstructure, final properties improvements and no damage to coating, thanks to controlled energy input and fast thermal cycles. IR imaging and force-torque monitoring are used to characterise the forming process. Residual stress measurement, microstructure, microhardness and EBSD are used to study the formed parts under the combined action of laser and mechanical force. A micromechanism of laser assisted spinning is proposed, as well as advantages and limitations of the technique.

  8. Comparative evaluation of visual outcomes and corneal asphericity after laser-assisted in situ keratomileusis with the six-dimension Amaris excimer laser system

    Science.gov (United States)

    Piao, JunJie; Li, Ying-Jun; Whang, Woong-Joo; Choi, Mihyun; Kang, Min Ji; Lee, Jee Hye; Yoon, Geunyoung; Joo, Choun-Ki

    2017-01-01

    Purpose To compare the visual and refractive outcomes after laser-assisted in situ keratomileusis (LASIK) surgery for correction of myopia or myopic astigmatism using a six-dimensional Amaris excimer laser. Methods In this retrospective cohort study, we enrolled 47 eyes of 28 patients (age: 19–36 years) with myopia or myopic astigmatism. We used the Custom Ablation Manager protocol and performed ablations with the SCHWIND AMARIS system. LASIK flaps were cut with an iFS Advanced Femtosecond Laser. Mean static (SCC) and dynamic cyclotorsion (DCC) were evaluated. Visual and refractive outcomes were evaluated during 6 months’ follow-up. Corneal asphericity (Q-value) was analyzed at 4 months postoperatively. Results The spherical equivalent (SE) reduction was statistically significant reduce 1 day after refractive surgery (P Free mode (AF) and 90% in the Corneal Wavefront mode (CW). SCC measurements were within ± 5 degrees in 57% (AF) and 68% (CW) of eyes. Mean DCC was within ± 1 degree in 96% (AF) or 95% (CW) of cases. At 6 months, the uncorrected distance visual acuity was 20/25 or better in all eyes. At last follow-up, both steep and flat keratometry values had significantly flattened in both groups (P < 0.001). Corneal asphericity also increased significantly during the postoperative period for an 8-mm corneal diameter (P < 0.001). Conclusions LASIK for myopia or myopic compound astigmatism correction using the six-dimensional AMARIS 750S excimer laser is safe, effective, and predictable. Postoperative corneal asphericity can be analyzed by linear regression to predict the changes in postoperative corneal asphericity with this approach. PMID:28187180

  9. Dacriocistorrinostomia transcanalicular com laser diodo: resultados preliminares Transcanalicular laser-assisted dacryocystorhinostomy: initial results

    Directory of Open Access Journals (Sweden)

    Ricardo Tomoyoshi Kanecadan

    2006-10-01

    Full Text Available OBJETIVO: Descrever a técnica e os resultados iniciais da dacriocistorrinostomia com laser diodo, realizada pela via transcanalicular. MÉTODOS: Dez pacientes com diagnóstico de obstrução lacrimal baixa foram submetidos à dacriocistorrinostomia com laser diodo, realizada pela via transcanalicular. A via lacrimal foi entubada com silicone, onde deveria permanecer por 6 meses. RESULTADOS: Todas as dez cirurgias foram realizadas sem intercorrências. Um paciente apresentou saída do tubo de silicone, um dia após a cirurgia. Após uma semana, os outros nove, relataram desaparecimento da epífora. Durante o primeiro mês de seguimento, mais um paciente apresentou perda do tubo de silicone e outro voltou apresentar epífora, por obstrução da fístula lacrimonasal. CONCLUSÕES: A dacriocistorrinostomia assistida por laser diodo, realizada pela via transcanalicular, é novo método para tratamento da obstrução das vias lacrimais. Com o desenvolvimento desta técnica espera-se aumento no índice de sucesso cirúrgico, tanto imediato como a longo prazo.PURPOSE: To describe the technique and initial results of laser-assisted dacryocystorhinostomy performed through the canaliculi. METHODS: Ten patients with nasolacrimal duct obstruction underwent transcanalicular laser-assisted dacryocystorhinostomy. A silicone tube was inserted through the canaliculi and the ostium into the nasal cavity where it will be kept for 6 months. RESULTS: All ten operations were performed without negative occurrences. One patient presented displacement of the silicone tube one day after surgery. Nine of the ten patients reported disappearance of epiphora at the end of the first week following surgery. During the first month, one of these patients presented with epiphora due to obstruction of the lacrimal-nasal fistula and another lost the silicone tube in the first month following surgery. CONCLUSIONS: Transcanalicular laser-assisted dacryocystorhinostomy is a

  10. Laser-assisted modification of polymers for microfluidic, micro-optics, and cell culture applications

    Science.gov (United States)

    Pfleging, W.; Adamietz, R.; Brückner, H. J.; Bruns, M.; Welle, A.

    2007-02-01

    Laser-assisted patterning of polymers is investigated for the direct fabrication of polymeric lab-on-a-chip devices in microsystem technology for capillary electrophoresis chips in bio-analytical applications. In many cases the laser process induces a chemical, physical and topographical change in the laser treated surface. This material modification significantly influences the lab-on-a-chip-functionalities. We will present our current research results in laser-assisted modification of polystyrene (PS) and polymethylmethacrylate (PMMA) with respect to applications in micro-optics, micro-fluidics and cell culture applications. For this purpose the refractive index change, the wettability and the adsorption of proteins and the adhesion of animal cells were investigated as function of laser- and processing parameters. The possible change of surface chemistry was characterized by X-ray photoelectron spectroscopy. The local UV-laser-assisted formation of chemical structures suitable for improved cell adhesion was realized on two- and three-dimensional PS and polycarbonate (PC) surfaces. Above and below the laser ablation threshold two different mechanisms were detected. In one case the produced debris was responsible for improved cell adhesion, while in the other case a photolytical activation of the polymer surface including a subsequent oxidization in oxygen or ambient air leads to a highly localized alteration of protein adsorption from cell culture media and increased cell adhesion. The highly localized control of wettability on polymeric surfaces was investigated for PS and PMMA. In the case of PS the dynamic advancing contact angle could be adjusted between 2° and 150°. This was possible for a suitable exposure dose and an appropriate choice of processing gas (helium or oxygen). A similar but not so significant effect was observed for PMMA below the laser ablation threshold. For PMMA the dynamic advancing contact angle could be adjusted between nearly 50° and

  11. Analysis of the changes in keratoplasty indications and preferred techniques.

    Directory of Open Access Journals (Sweden)

    Stefan J Lang

    Full Text Available Recently, novel techniques introduced to the field of corneal surgery, e.g. Descemet membrane endothelial keratoplasty (DMEK and corneal crosslinking, extended the therapeutic options. Additionally contact lens fitting has developed new alternatives. We herein investigated, whether these techniques have affected volume and spectrum of indications of keratoplasties in both a center more specialized in treating Fuchs' dystrophy (center 1 and a second center that is more specialized in treating keratoconus (center 2.We retrospectively reviewed the waiting lists for indication, transplantation technique and the patients' travel distances to the hospital at both centers.We reviewed a total of 3778 procedures. Fuchs' dystrophy increased at center 1 from 17% (42 to 44% (150 and from 13% (27 to 23% (62 at center 2. In center 1, DMEK increased from zero percent in 2010 to 51% in 2013. In center 2, DMEK was not performed until 2013. The percentage of patients with keratoconus slightly decreased from 15% (36 in 2009 vs. 12% (40 in 2013 in center 1. The respective percentages in center 2 were 28% (57 and 19% (51. In both centers, the patients' travel distances increased.The results from center 1 suggest that DMEK might increase the total number of keratoplasties. The increase in travel distance suggests that this cannot be fully attributed to recruiting the less advanced patients from the hospital proximity. The increase is rather due to more referrals from other regions. The decrease of keratoconus patients in both centers is surprising and may be attributed to optimized contact lens fitting or even to the effect corneal crosslinking procedure.

  12. Femtosecond Laser Filamentation

    CERN Document Server

    Chin, See Leang

    2010-01-01

    Femtosecond Laser Filamentation gives a comprehensive review of the physics of propagation of intense femtosecond laser pulses in optical media (principally air) and the applications and challenges of this new technique. This book presents the modern understanding of the physics of femtosecond laser pulse propagation, including unusual new effects such as the self-transformation of the pulse into a white light laser pulse, intensity clamping, the physics of multiple filamentation and competition, and how filaments’ ability to melt glass leads to wave guide writing. The potential applications of laser filamentation in atmospheric sensing and the generation of other electromagnetic pulses from the UV to the radio frequency are treated, together with possible future challenges in the excitation of super-excited states of molecules. Exciting new phenomena such as filament induced ultrafast birefringence and the excitation of molecular rotational wave packets and their multiple revivals in air (gases) will also ...

  13. Micromachining using femtosecond lasers

    Science.gov (United States)

    Toenshoff, Hans K.; Ostendorf, Andreas; Nolte, Stefan; Korte, Frank; Bauer, Thorsten

    2000-11-01

    Femtosecond laser systems have been proved to be effective tools for high precision micro-machining. Almost all solid materials can be processed with high precision. The dependence on material properties like thermal conductivity, transparency, heat- or shock sensitivity is strongly reduced and no significant influence on the remaining bulk material is observed after ablation using femtosecond laser pulses. In contrast to conventional laser processing, where the achievable precision is reduced due to a formed liquid phase causing burr formation, the achievable precision using femtosecond pulses is only limited by the diffraction of the used optics. Potential applications of this technique, aincluding the structuring of biodegradable polymers for cardiovascular implants, so-called stents, as well as high precision machining of transparent materials are presented.

  14. Femtosecond laser spectroscopy

    CERN Document Server

    Hannaford, Peter

    2005-01-01

    As concepts and methodologies have evolved over the past two decades, the realm of ultrafast science has become vast and exciting and has impacted many areas of chemistry, biology and physics, and other fields such as materials science, electrical engineering, and optical communication. The field has recently exploded with the announcement of a series of remarkable new developments and advances. This volume surveys this recent growth in eleven chapters written by leading international researchers in the field. It includes sections on femtosecond optical frequency combs, soft x-ray femtosecond laser sources, and attosecond laser sources. In addition, the contributors address real-time spectroscopy of molecular vibrations with sub-5-fs pulses and multidimensional femtosecond coherent spectroscopies for studying molecular and electron dynamics. Novel methods for measuring and characterizing ultrashort laser pulses and ultrashort pulses of light are also described. The topics covered are revolutionizing the field...

  15. Evaluation of tissue tightening by the subdermal Nd: Yag laser-assisted liposuction versus liposuction alone

    Directory of Open Access Journals (Sweden)

    Alberto Goldman

    2011-01-01

    Full Text Available Background: Skin tightening is a desirable outcome for skin flaccidity. Objective: We evaluated the applicability, safety, capacity and intensity of skin tightening with the subdermal 1,064 nm Nd: YAG laser application to the upper arms, and compared the results with liposuction. Materials and Methods: Patients with lipodystrophy and mild-to-severe skin laxity of the arms were included (n=28. In half of patients, a single treatment with a subcutaneous laser and liposuction was performed, while the other 14 had a regular liposuction. Treatment parameters, adverse effects and photographic documentation were recorded. Results: Aesthetic improvement and skin retraction was superior by laser lipolysis. The procedure was well tolerated without significant complications. Conclusions: The subdermal laser-assisted liposuction using a 1,064 nm Nd: YAG laser achieves improved skin tightening.

  16. Monte Carlo simulations of multiple scattering effects in laser assisted free-free scattering experiments

    Science.gov (United States)

    Deharak, B. A.; Savich, J. L.; Roberts, H. M.; Brown, E. G.; McGill, M. R.; Kim, B. N.; Weaver, C. M.; Martin, N. L. S.

    2016-05-01

    We have conducted a series of Monte Carlo simulations of laser assisted free-free scattering experiments. The simulations make use of Kroll-Watson approximation to account for the effects of the laser field on the scattering process. The parameters for these simulations are believed to mimic the experimental conditions of the work reported by Wallbank and Holmes, particularly the target number density. The simulations account for the effects multiple scattering (i.e., the scattering of a single incident electron from multiple target atoms). We present a comparison of the results of these simulations to the experimental results of Wallbank and Holmes. This work was supported by the National Science Foundation under Grants Nos. PHY-0855040 (NLSM) and PHY-1402899 (BAd).

  17. Laser-assisted gingivectomy in pediatric patients: A novel alternative treatment

    Directory of Open Access Journals (Sweden)

    G Gontiya

    2011-01-01

    Full Text Available Gingival enlargement is quite a common pathology in pediatric patients and may be inflammatory, noninflammatory, or a combination of both. Idiopathic gingival fibromatosis, although rare, is a slowly progressive benign enlargement that affects the marginal gingiva, attached gingival, and interdental papilla. The fibromatosis may potentially cover the exposed tooth surfaces, causing esthetic and functional problems. The treatment of gingival fibromatosis is essential because it causes difficulties with mastication, speech problems, mispositioning of teeth, esthetic effects, and psychological difficulties for the patient. Traditional gingivectomy procedures have been a challenge for dentists who confront issues of patient cooperation and discomfort. In the last decade, laser procedures in oral cavity had shown many optimum effects in both hard and soft tissue procedures. Laser soft-tissue surgery has been shown to be well accepted by children. The following case report describes a laser-assisted gingivectomy procedure performed on a 13-year-old female.

  18. Laser-assisted gingivectomy in pediatric patients: a novel alternative treatment.

    Science.gov (United States)

    Gontiya, G; Bhatnagar, S; Mohandas, U; Galgali, S R

    2011-01-01

    Gingival enlargement is quite a common pathology in pediatric patients and may be inflammatory, noninflammatory, or a combination of both. Idiopathic gingival fibromatosis, although rare, is a slowly progressive benign enlargement that affects the marginal gingiva, attached gingival, and interdental papilla. The fibromatosis may potentially cover the exposed tooth surfaces, causing esthetic and functional problems. The treatment of gingival fibromatosis is essential because it causes difficulties with mastication, speech problems, mispositioning of teeth, esthetic effects, and psychological difficulties for the patient. Traditional gingivectomy procedures have been a challenge for dentists who confront issues of patient cooperation and discomfort. In the last decade, laser procedures in oral cavity had shown many optimum effects in both hard and soft tissue procedures. Laser soft-tissue surgery has been shown to be well accepted by children. The following case report describes a laser-assisted gingivectomy procedure performed on a 13-year-old female.

  19. Laser-assisted nanomaterial deposition, nanomanufacturing, in situ monitoring and associated apparatus

    Science.gov (United States)

    Mao, Samuel S; Grigoropoulos, Costas P; Hwang, David J; Minor, Andrew M

    2013-11-12

    Laser-assisted apparatus and methods for performing nanoscale material processing, including nanodeposition of materials, can be controlled very precisely to yield both simple and complex structures with sizes less than 100 nm. Optical or thermal energy in the near field of a photon (laser) pulse is used to fabricate submicron and nanometer structures on a substrate. A wide variety of laser material processing techniques can be adapted for use including, subtractive (e.g., ablation, machining or chemical etching), additive (e.g., chemical vapor deposition, selective self-assembly), and modification (e.g., phase transformation, doping) processes. Additionally, the apparatus can be integrated into imaging instruments, such as SEM and TEM, to allow for real-time imaging of the material processing.

  20. Low-level laser-assisted liposuction: the Neira 4 L technique.

    Science.gov (United States)

    Neira, Rodrigo; Toledo, Luiz; Arroyave, Jose; Solarte, Efrain; Isaza, Carolina; Gutierrez, Oscar; Criollo, William; Ramirez, Hugo; Gutierrez, Maria I; Ortiz-Neira, Clara L

    2006-01-01

    Low-level laser-assisted liposuction (LLLL), known as the Neira 4 L technique, is an excellent adjuvant tool for the surgeon practicing liposculpture. A low-level laser is used to create a transitory pore in the cell membrane of the adipocyte to move fat from inside the cell to the interstitial space outside without killing the cell. LLLL has been performed successfully in in-vitro and human adipose tissue cultures. It protects the patient from the surgical trauma of liposuction by protecting and preparing tissues for the surgical trauma; modulating the inflammatory response to prevent short and long-term side effects of surgery; and improving the quality and quantity of the healing process by accelerating recovery time, modulating secondary cicatrization, and preventing postoperative neuralgias.

  1. Conventional dacryocystorhinostomy in a failed Trans-canalicular laser-assisted dacryocystorhinostomy

    Directory of Open Access Journals (Sweden)

    Rajesh Subhash Joshi

    2011-01-01

    Full Text Available We report the success rate and problems associated with conventional dacryocystorhinostomy (DCR in failed cases of Trans-canalicular, laser-assisted DCR (TCLADCR. Out of 50 patients operated by the TCLADCR technique during the period 2005 - 2006, 33 patients had failure, which was confirmed on syringing of the nasolacrimal passage. Before considering them for conventional DCR, a thorough ear, nose, throat (ENT examination was done by an ENT surgeon, to rule out a nasal pathology. All the patients were operated by the conventional standard DCR method at a medical college. While performing the surgery, the problems that came across were identified and noted. The success rate was found to be 91% in this study in a follow-up period of one year, with no major intra-operative problems. Conventional DCR is still a gold standard and should be considered as a procedure of choice in failed cases of TCLDCR.

  2. Laser-assisted reduction of graphene oxide for paper based large area flexible electronics

    Science.gov (United States)

    Balliu, E.; Andersson, H.; Engholm, M.; Forsberg, S.; Olin, H.

    2016-03-01

    In this work we present a promising method for fabrication of conductive tracks on paper based substrates by laser assisted reduction of Graphene Oxide (GO). Printed electronics on paper based substrates is be coming more popular due to lower cost and recyclability. Fabrication of conductive tracks is of great importance where metal, carbon and polymer inks are commonly used. An emerging option is reduced graphene oxide (r-GO), which can be a good conductor. Here we have evaluated reduction of GO by using a 532 nm laser source, showing promising results with a decrease of sheet resistance from >100 M Ω/Sqr for unreduced GO down to 126 Ω/Sqr. without any observable damage to the paper substrates.

  3. Thermal laser-assisted angioplasty of renal artery stenosis for renovascular hypertension.

    Science.gov (United States)

    Tani, M; Mizuno, K; Midorikawa, H; Igari, T; Egawa, M; Niimura, S; Fukuchi, S; Hoshino, S

    1993-01-01

    Percutaneous transluminal laser-assisted angioplasty of a renal artery stenosis was performed in a 16-year-old woman with renovascular hypertension. The stenotic portion of the renal artery was predilated by delivering Nd-YAG laser energy to the terminal tip of a laser catheter. Although the luminal diameter did not increase sufficiently with laser angioplasty alone, it allowed passage of the balloon catheter and subsequent successful balloon angioplasty. Immediately after dilatation, the patient's blood pressure fell to normal, and plasma renin activity decreased. There were no serious complications. Thermal laser angioplasty seems to be an effective adjunct technique for the treatment of severe renal artery stenosis which does not allow initial passage of a balloon catheter.

  4. Evaporation mechanisms of MgO in laser assisted atom probe tomography

    KAUST Repository

    Mazumder, Baishakhi

    2011-05-01

    In this paper the field evaporation properties of bulk MgO and sandwiched MgO layers in Fe are compared using laser assisted Atom Probe Tomography. The comparison of flight time spectra gives an estimate of the evaporation times as a function of the wavelength and the laser energy. It is shown that the evaporation takes place in two steps on two different time scales in MgO. It is also shown that as long as the MgO layer is buried in Fe, the evaporation is dominated by the photon absorption in Fe layer at the tip apex. Eventually the evaporation process of MgO is discussed based on the difference between the bulk materials and the multilayer samples. © 2010 Elsevier B.V.

  5. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    Science.gov (United States)

    Shaji, S.; Garcia, L. V.; Loredo, S. L.; Krishnan, B.; Aguilar Martinez, J. A.; Das Roy, T. K.; Avellaneda, D. A.

    2017-01-01

    Antimony sulfide (Sb2S3) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb2S3 thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb2S3 thin films for optoelectronic applications.

  6. Significance of the Resonance Condition for Controlling the Seam Position in Laser-assisted TIG Welding

    Science.gov (United States)

    Emde, B.; Huse, M.; Hermsdorf, J.; Kaierle, S.; Wesling, V.; Overmeyer, L.; Kozakov, R.; Uhrlandt, D.

    As an energy-preserving variant of laser hybrid welding, laser-assisted arc welding uses laser powers of less than 1 kW. Recent studies have shown that the electrical conductivity of a TIG welding arc changes within the arc in case of a resonant interaction between laser radiation and argon atoms. This paper presents investigations on how to control the position of the arc root on the workpiece by means of the resonant interaction. Furthermore, the influence on the welding result is demonstrated. The welding tests were carried out on a cooled copper plate and steel samples with resonant and non-resonant laser radiation. Moreover, an analysis of the weld seam is presented.

  7. A prospective 9-month human clinical evaluation of Laser-Assisted New Attachment Procedure (LANAP) therapy.

    Science.gov (United States)

    Nevins, Marc; Kim, Soo-Woo; Camelo, Marcelo; Martin, Ignacio Sanz; Kim, David; Nevins, Myron

    2014-01-01

    This investigation was designed and implemented as a single-center, prospective study to evaluate the clinical response to the Laser-Assisted New Attachment Procedure (LANAP). Eight patients with advanced periodontitis were enrolled and treated with full-mouth LANAP therapy and monitored for 9 months. Fullmouth clinical measurements, including clinical attachment level (CAL), probing depth (PD), and recession, were provided at baseline and after 9 months of healing by a single calibrated examiner, including a total of 930 sites and 444 sites with initial PD equal to or greater than 5 mm. Clinical results for the 930 sites measured pre- and postoperatively revealed that mean PD was reduced from 4.62 ± 2.29 mm to 3.14 ± 1.48 mm after 9 months (P LANAP therapy should be further investigated with long-term clinical trials to compare the stability of clinical results with conventional therapy.

  8. Fast steel-cleanness characterization by means of laser-assisted plasma spectrometric methods.

    Science.gov (United States)

    Müller, Gregor; Stahnke, Frank; Bleiner, Davide

    2006-12-15

    Laser-assisted plasma spectrometry is a palette of analytical techniques (L-OES, LA-ICP-MS) capable of fast spatially-resolved elemental analysis in the micrometer range. For fast estimation of the occurrence in steel samples of non-metallic inclusions, which degrade the material's technical properties, simultaneous OES detection and sequential ICP-MS detection were compared. Histograms were obtained for the intensity distribution of the acquired signals (laser pulse statistics). The skewness coefficient of the histograms for Al (indicator of non-metallic inclusions) was found to be clearly dependent on the fraction of non-metallic inclusions in the case of scanning L-OES. For LA-ICP-MS less clear dependence was observed, which was influenced by the acquisition characteristics. In fact, less measurement throughput limited for LA-ICP-MS the counting statistics to an extent that overrides the benefit of higher detection power as compared to L-OES.

  9. Pustulotic arthro-osteitis report of a case successfully treated with laser-assisted arthroscopic synovectomy.

    Science.gov (United States)

    Yamada, K; Imaizumi, T; Uemura, M

    1999-02-01

    A 61-year-old man with palmoplantar pustulosis had pain and swelling persisting in his left knee for more than 3 years. The rheumatoid factor and HLA B 27 antigen were absent. Plain radiographs of the knee revealed no abnormalities despite the persistent synovitis. The bone scintigraphy showed increased uptake in the manubriosternal joint as well as in the knee. Eventually, the patient underwent arthroscopic synovectomy assisted with a holmium: YAG laser. No postoperative complications such as hemarthrosis were noted. The patient was pain free with full range of motion of the knee 22 months after surgery. Peripheral arthritis associated with palmoplantar pustulosis is usually transient. This unique case suggests that laser-assisted arthroscopic synovectomy would be a useful therapeutic option for persistent severe synovitis resistant to conservative treatment in pustulotic arthro-osteitis.

  10. A meta-analysis of aneurysm formation in laser assisted vascular anastomosis (LAVA)

    Science.gov (United States)

    Chen, Chen; Peng, Fei; Xu, Dahai; Cheng, Qinghua

    2009-08-01

    Laser assisted vascular anastomosis (LAVA) is looked as a particularly promising non-suture method in future. However, aneurysm formation is one of the main reasons delay the clinical application of LAVA. Some scientists investigated the incidence of aneurysms in animal model. To systematically analyze the literature on reported incidence of aneurysm formation in LAVA therapy, we performed a meta-analysis comparing LAVA with conventional suture anastomosis (CSA) in animal model. Data were systematically retrieved and selected from PUBMED. In total, 23 studies were retrieved. 18 studies were excluded, and 5 studies involving 647 animals were included. Analysis suggested no statistically significant difference between LAVA and CSA (OR 1.24, 95%CI 0.66-2.32, P=0.51). Result of meta analysis shows that the technology of LAVA is very close to clinical application.

  11. Relativistic electronic dressing in laser-assisted ionization of atomic hydrogen by electron impact

    CERN Document Server

    Attaourti, Y

    2004-01-01

    Within the framework of the coplanar binary geometry where it is justified to use plane wave solutions for the study of the $(e,2e)$ reaction and in the presence of a circularly polarized laser field, we introduce as a first step the DVRPWBA1 (Dirac-Volkov Plane Wave Born Approximation1) where we take into account only the relativistic dressing of the incident and scattered electrons. Then, we introduce the DVRPWBA2 (Dirac-Volkov Plane Wave Born Approximation2) where we take totally into account the relativistic dressing of the incident, scattered and ejected electrons. We then compare the corresponding triple differential cross sections for laser-assisted ionization of atomic hydrogen by electron impact both for the non relativistic and the relativistic regime.

  12. Effect of bound-state dressing in laser-assisted radiative recombination

    Science.gov (United States)

    Müller, Robert A.; Seipt, Daniel; Fritzsche, Stephan; Surzhykov, Andrey

    2015-11-01

    We present a theoretical study on the recombination of a free electron into the ground state of a hydrogenlike ion in the presence of an external laser field. Emphasis is placed on the effects caused by the laser dressing of the residual ionic bound state. To investigate how this dressing affects the total and angle-differential cross section of laser-assisted radiative recombination (LARR) we apply first-order perturbation theory and the separable Coulomb-Volkov continuum ansatz. Using this approach, detailed calculations are performed for low-Z hydrogenlike ions and laser intensities in the range from IL=1012 to 1013W/cm2 . It is seen that the total cross section as a function of the laser intensity is remarkably affected by the bound-state dressing. Moreover, the laser dressing becomes manifest as asymmetries in the angular distribution and the (energy) spectrum of the emitted recombination photons.

  13. Laser assisted vascular anastomosis (LAVA): a promising nonsuture technique for surgery

    Science.gov (United States)

    Chen, Chen; Peng, Fei; Xu, Dahai; Cheng, Qinghua

    2009-08-01

    The first successful experiment of laser vascular welding was reported in 1979. Laser assisted vascular anastomosis (LAVA) is looked as a particularly promising non-suture method in future. We performed a Medline literature search on laser vessel welding combined with cross-referencing. According to the former experimental animal studies, CO2-, argon-, diode-, KTP-, Holmium:YAG-, and Nd:YAG-lasers have been used for LAVA. Almost all lasers have been used in combination with stay suture and/or solders in order to improve the strength on anastomosis site. Advantages of LAVA are minimal vessel damage, faster operation and the potential for minimally invasive application. However, the clinical application of LAVA is still seldom employed because of aneurysm formation. In conclusion of the literature study, the diode laser is the most popular, but long-term evaluation is required.

  14. Relaxing incision for control of postoperative astigmatism following keratoplasty.

    Science.gov (United States)

    Troutman, R C; Swinger, C

    1980-02-01

    A new technique has been presented which provides a second surgical approach to correct excessive residual astigmatism following keratoplasty. The relaxing incision procedure has advantages over wedge resection in that it can be performed at the slit lamp, it gives no initial overcorrection, and it has a much shorter postoperative course while giving rapid results without suturing. Since this technique does not appear to produce significant hyperopia and may produce a tendency toward myopia, the corneal surgeon would thus have alternative techniques from which to choose, depending, in part, on the spherical component of the refraction.

  15. "Blow-torch phenomenon" during laser assisted excision of a thyroglossal cyst at the base of the tongue

    Directory of Open Access Journals (Sweden)

    Anitha G Bhat

    2012-01-01

    Full Text Available We report a case of blow-torch phenomenon encountered during diode laser assisted excision of a thyroglossal cyst in a child. This is first such case report from India and highlights an unusual complication which anesthesiologists need to be aware of due to the increasing use of operative laser.

  16. Evaluation of microstructure and micro-hardness of 410L SS coatings fabricated using laser assisted cold spraying: process development

    CSIR Research Space (South Africa)

    Mathebula, TE

    2014-11-01

    Full Text Available , contaminating and erosive environments which accelerate the degradation of these components. Surface coatings are generally used to protect and prolong the lifetime of the parts. Laser Assisted Cold Spray (LACS) is a relatively new surface coating process which...

  17. Laser-assisted growth of carbon nanotubes on laser-patterned substrates and inside sealed micro-channels

    NARCIS (Netherlands)

    Burgt, Y. van de; Bellouard, Y.

    2014-01-01

    Carbon nanotube assemblies can be used for specific applications such as sensors and filters. We present a method and proof-of-concept to directly grow vertically-aligned carbon nanotube structures within sealed enclosures by means of a feedback-controlled laser-assisted chemical vapor deposition te

  18. Isolation of human adipose-derived stromal cells using laser-assisted liposuction and their therapeutic potential in regenerative medicine.

    Science.gov (United States)

    Chung, Michael T; Zimmermann, Andrew S; Paik, Kevin J; Morrison, Shane D; Hyun, Jeong S; Lo, David D; McArdle, Adrian; Montoro, Daniel T; Walmsley, Graham G; Senarath-Yapa, Kshemendra; Sorkin, Michael; Rennert, Robert; Chen, Hsin-Han; Chung, Andrew S; Vistnes, Dean; Gurtner, Geoffrey C; Longaker, Michael T; Wan, Derrick C

    2013-10-01

    Harvesting adipose-derived stromal cells (ASCs) for tissue engineering is frequently done through liposuction. However, several different techniques exist. Although third-generation ultrasound-assisted liposuction has been shown to not have a negative effect on ASCs, the impact of laser-assisted liposuction on the quality and differentiation potential of ASCs has not been studied. Therefore, ASCs were harvested from laser-assisted lipoaspirate and suction-assisted lipoaspirate. Next, in vitro parameters of cell yield, cell viability and proliferation, surface marker phenotype, osteogenic differentiation, and adipogenic differentiation were performed. Finally, in vivo bone formation was assessed using a critical-sized cranial defect in athymic nude mice. Although ASCs isolated from suction-assisted lipoaspirate and laser-assisted lipoaspirate both successfully underwent osteogenic and adipogenic differentiation, the cell yield, viability, proliferation, and frequency of ASCs (CD34(+)CD31(-)CD45(-)) in the stromal vascular fraction were all significantly less with laser-assisted liposuction in vitro (p liposuction appears to negatively impact the biology of ASCs, cell harvest using suction-assisted liposuction is preferable for tissue-engineering purposes.

  19. Solid protein solder-doped biodegradable polymer membranes for laser-assisted tissue repair

    Science.gov (United States)

    Hodges, Diane E.; McNally-Heintzelman, Karen M.; Welch, Ashley J.

    2000-05-01

    Solid protein solder-doped polymer membranes have been developed for laser-assisted tissue repair. Biodegradable polymer films of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) using a solvent-casting and particulate-leaching technique. The films provided a porous scaffold that readily absorbed the traditional protein solder mix composed of bovine serum albumin (BSA) and indocyanine green (ICG) dye. In vitro investigations were conducted to assess the influence of various processing parameters on the strength of tissue repairs formed using the new membranes. These parameters included the PLGA copolymer and PLGA/PEG blend ratio, the salt particle size, the initial bovine serum albumin (BSA) weight fraction, and the laser irradiance used to denature the solder. Altering the PLGA copolymer ratio had little effect on repair strength, however, it influenced the membrane degradation rate. Repair strength increased with increased membrane pore size and BSA concentration. The addition of PEG during the film casting stage increased the flexibility of the membranes but not necessarily the repair strength. The repair strength increased with increasing irradiance from 12 W/cm2 to 15 W/cm2. The new solder-doped polymer membranes provide all of the benefits associated with solid protein solders including high repair strength and improved edge coaptation. In addition, the flexible and moldable nature of the new membranes offer the capability of tailoring the membranes to a wide range of tissue geometries, and consequently, improved clinical applicability of laser- assisted tissue repair.

  20. Laser-assisted preparation and photoelectric properties of grating-structured Pt/FTO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Nai-fei, E-mail: rnf_ujs@126.com [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Huang, Li-jing, E-mail: lij_huang@126.com [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Li, Bao-jia [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhou, Ming [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2014-09-30

    Highlights: • Pt layers were deposited by DC magnetron sputtering on commercial FTO glasses. • Pt/FTO films were irradiated by laser for inducing gratings and annealing. • An ideal grating-structured Pt/FTO film was obtained using a fluence of 1.05 J/cm{sup 2}. • The grating-structured Pt/FTO film exhibited excellent photoelectric properties. • Laser-assisted treatment is effective for improving performance of FTO-based films. - Abstract: In order to improve the transparency and conductivity of commercial fluorine-doped tin oxide (FTO) glass, platinum (Pt) layers were deposited on the FTO film by direct current (DC) magnetron sputtering, followed by being irradiating with a 532 nm nanosecond pulsed laser for the dual purpose of inducing grating structures and annealing. Introducing a Pt layer decreased the average transmittance (400–800 nm) and the sheet resistance of the initial FTO film from 80.2% and 8.4 Ω/sq to 68.6% and 7.9 Ω/sq, respectively. The ideal grating-structured Pt/FTO film was obtained by laser irradiation with a fluence of 1.05 J/cm{sup 2}, and X-ray diffraction (XRD) analysis confirmed that this film underwent optimal annealing. As a result, it exhibited an average transmittance (400–800 nm) of 84.1% and a sheet resistance of 6.8 Ω/sq. These results indicated that laser-assisted treatment combined with introduction of metal layer can effectively improve photoelectric properties of FTO single-layer films.

  1. Laser-assisted inkjet printing of highly viscous fluids with sub-nozzle resolution

    Science.gov (United States)

    Delrot, Paul; Modestino, Miguel A.; Psaltis, Demetri; Moser, Christophe

    2016-04-01

    Drop-on-demand inkjet printing is mostly based on thermal and piezo-actuation, allowing for densely packed nozzles in inkjet printers. However, the droplet diameter is typically defined by the nozzle diameter, thus limiting the range of viscosity that can be jetted to 10-100 mPa.s to prevent nozzle clogging. Here, we present a laser-assisted system for the delivery of micro-droplets of highly viscous fluids with sub-nozzle resolution. Highly focused supersonic jets have recently been demonstrated by focusing a nanosecond pulse of light into a micro-capillary filled with dyed water, hence generating a cavitation bubble. The consequent pressure wave impact on the concave free surface of the liquid generated flow-focused micro-jets. We implemented this technique for the production of low velocity micro-droplets with photopolymer inks of increasing viscosity (0.6-148 mPa.s) into a 300 μm-wide glass capillary using low laser energies (3-70 μJ). Time-resolved imaging provided details on the droplet generation. Single micro-droplets of diameter 70-80 μm were produced on demand with inks of viscosity 0.6-9 mPa.s with good controllability and reproducibility, thus enabling to print two-dimensional patterns with a precision of 13 μm. Furthermore, the primary droplet produced with the most viscous fluid was about 66% of the capillary diameter. Preliminary results also showed that the process is linearly scalable to narrower capillaries (100-200 μm), thus paving the way for a compact laser-assisted inkjet printer. A possible application of the device would be additive manufacturing as the printed patterns could be consequently cured.

  2. Exploring the potential of laser assisted flow deposition grown ZnO for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, J., E-mail: joana.catarina@ua.pt [Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Cerqueira, A.F.R.; Sousa, M.G.; Santos, N.F. [Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal); Pimentel, A.; Fortunato, E. [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Cunha, A.F. da; Monteiro, T.; Costa, F.M. [Departamento de Física & I3N, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro (Portugal)

    2016-07-01

    Zinc oxide (ZnO) is a widely studied wide band gap semiconductor with applications in several fields, namely to enhance solar cells efficiency. Its ability to be grown in a wide variety of nanostructured morphologies, allowing the designing of the surface area architecture constitutes an important advantage over other semiconductors. Laser assisted flow deposition (LAFD) is a recently developed growth method, based on a vapour-solid mechanism, which proved to be a powerful approach in the production of ZnO micro/nanostructures with different morphologies as well as high crystallinity and optical quality. In the present work we report the use of the LAFD technique to grow functional ZnO nanostructures (nanoparticles and tetrapods) working as nano templates to improve the dye-sensitized solar cells (DSSCs) efficiency. The structural and morphological characterization of the as-grown ZnO crystals were performed by X-ray diffraction and electron microscopy, respectively, and the optical quality was assessed by photoluminescence spectroscopy. DSSCs were produced using a combination of these nanostructures, which were subsequently sensitized with N719 dye. An efficiency of ∼3% was achieved under simulated AM 1.5 illumination conditions for a dye loading time of 1 h. - Highlights: • Laser assisted flow deposition proved to be an efficient technique to produce high quality ZnO. • Active layer formed by an interconnected network of tetrapods and a small amount of nanoparticles. • Efficiency of ∼3% obtained under simulated AM 1.5 illumination conditions.

  3. In vivo laser assisted end-to-end anastomosis with ICG-infused chitosan patches

    Science.gov (United States)

    Rossi, Francesca; Matteini, Paolo; Esposito, Giuseppe; Scerrati, Alba; Albanese, Alessio; Puca, Alfredo; Maira, Giulio; Rossi, Giacomo; Pini, Roberto

    2011-07-01

    Laser assisted vascular repair is a new optimized technique based on the use of ICG-infused chitosan patch to close a vessel wound, with or even without few supporting single stitches. We present an in vivo experimental study on an innovative end-to-end laser assisted vascular anastomotic (LAVA) technique, performed with the application of ICGinfused chitosan patches. The photostability and the mechanical properties of ICG-infused chitosan films were preliminary measured. The in vivo study was performed in 10 New Zealand rabbits. After anesthesia, a 3-cm segment of the right common carotid artery was exposed, thus clamped proximally and distally. The artery was then interrupted by means of a full thickness cut. Three single microsutures were used to approximate the two vessel edges. The ICG-infused chitosan patch was rolled all over the anastomotic site and welded by the use of a diode laser emitting at 810 nm and equipped with a 300 μm diameter optical fiber. Welding was obtained by delivering single laser spots to induce local patch/tissue adhesion. The result was an immediate closure of the anastomosis, with no bleeding at clamps release. Thus animals underwent different follow-up periods, in order to evaluate the welded vessels over time. At follow-up examinations, all the anastomoses were patent and no bleeding signs were documented. Samples of welded vessels underwent histological examinations. Results showed that this technique offer several advantages over conventional suturing methods: simplification of the surgical procedure, shortening of the operative time, better re-endothelization and optimal vascular healing process.

  4. Corneal endothelium after deep anterior lamellar keratoplasty and penetrating keratoplasty for keratoconus: A four-year comparative study

    Directory of Open Access Journals (Sweden)

    Anil Kubaloglu

    2012-01-01

    Full Text Available Purpose: To compare the status of corneal endothelium and central corneal thickness within the first four postoperative years after deep anterior lamellar keratoplasty (DALK and penetrating keratoplasty (PK in patients with keratoconus. Materials and Methods: Thirty-nine eyes (Group A which had PK and 44 eyes (Group B which had DALK for the treatment of keratoconus were included in this retrospective study. The endothelial cell density (ECD, the mean endothelial cell area and the coefficient of variation of cell area were assessed with a non-contact specular microscope, and the central corneal thickness (CCT was measured with an ultrasound pachymeter. Results: Mean ECD loss rate at two years was 36.24% in Group A and 18.12% in Group B (P<0.001. Mean ECD loss rate at four years was 47.82% in Group A and 21.62% in Group B (P<0.001. Mean annual ECD loss rate was calculated 14.12% per year in Group A and 5.78% per year in Group B. In the PK group, increase in mean CCT was 15.60% in two years and 15.03% in four years, while in the DALK group, mean CCT increased by 8.05% in two years and 9.31% in four years. Conclusions: As the majority of ectatic disorders such as keratoconus occur in young people, long-term endothelial cell survival following treatment with keratoplasty is essential for the long-term visual ability. Our finding that corneal endothelial cell loss in the DALK group occurs at a slower rate than in the PK group suggests DALK as a safer alternative to PK in these selected patients.

  5. Candida albicans interface infection after deep anterior lamellar keratoplasty

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Sedaghat

    2012-01-01

    Full Text Available The clinical features of interface Candida keratitis after deep anterior lamellar keratoplasty (DALK, may imitate rejection or crystalline keratopathy. We report here an 18-year-old woman presented with red eye, 4 months after undergoing DALK. Slit lamp examination revealed keratic precipitates (KPs and cojunctival injection. She was prescribed corticosteroid treatment for endothelial rejection by another ophthalmologist because of misdiagnosis, but suffered a recurrence of symptoms after reduction of the corticosteroid treatment. At that time, she was referred to our office. The recurrence persisted despite antibiotic and antifungal therapies. Ten days after treatment with interface irrigation with amphotericin, the infiltration and hypopyon were resolved. Topical steroid was added after 3 months of antifungal monotherapy. Irrigant cultures confirmed the presence of Candida albicans. The corneal graft appeared semi-clear with no signs of infection at 17-month follow-up. We recommend a close follow-up and a timely intervention to prevent the need for more invasive treatment such as penetrating keratoplasty.

  6. Hybrid Technique of Lamellar Keratoplasty (DMEK-S

    Directory of Open Access Journals (Sweden)

    Pavel Studeny

    2013-01-01

    Full Text Available Purpose: To evaluate the outcomes of the hybrid technique of posterior lamellar keratoplasty (DMEK-S. Materials and Methods: 71 eyes of 55 patients enrolled in a single-center study underwent posterior lamellar keratoplasty with a hybrid lamella DMEK-S implanted using a solution implantation technique, owing to endothelial dysfunction. The outcome measures studied were visual acuity and endothelial cell density. Results: The rate of endothelial cell loss caused by surgery was 43.8%. During followups, we observed the stabilization of postoperative findings, or at minimum a very low rate of corneal endothelial cell loss. The UCDVA and BCDVA dramatically improved postoperatively. The rebubbling rate in our group of patients was 61.9%. We replaced the lamella due to its failure or malfunction in 17 patients (23.9%. Conclusion: In summary, DMEK-S combines the advantages of DSEK/DSAEK and DMEK. The central zone of bare Descemet’s membrane and endothelium allows for very good visual outcomes, and the peripheral rim allows for better manipulation of the lamella during implantation. It is an effective method of treating the endothelial dysfunction of various etiologies, but the high complication rate needs to be addressed before widespread implementation of the technique in the future.

  7. [PKP for Keratoconus - From Hand/Motor Trephine to Excimer Laser and Back to Femtosecond Laser].

    Science.gov (United States)

    Seitz, B; Szentmáry, N; Langenbucher, A; Hager, T; Viestenz, A; Janunts, E; El-Husseiny, M

    2016-06-01

    For patients with keratoconus, rigid gas-permeable contact lenses are the first line correction method and allow good visual acuity for quite some time. In severe stages of the disease with major cone-shaped protrusion of the cornea, even specially designed keratoconus contact lenses are no longer tolerated. If there are contraindications for intrastromal ring segments, corneal transplantation typically has a very good prognosis. In patients with advanced keratoconus - especially after corneal hydrops due to rupture of Descemet's membrane - penetrating keratoplasty (PKP) is still the first line surgical method. Non-contact excimer laser trephination seems to be especially beneficial for eyes with iatrogenic keratectasia after LASIK and for patients with repeat grafts due to "keratoconus recurrences" due to small grafts with thin host cornea. For donor trephination from the epithelial side, an artificial chamber is used. Wound closure is achieved with a double running cross-stitch suture according to Hoffmann. Graft size is adapted individually, depending on corneal size ("as large as possible - as small as necessary"). Limbal centration is preferred intraoperatively, due to optical displacement of the pupil. During the last 10 years, femtosecond laser trephination has been introduced from the USA as a potentially advantageous approach. Prospective clinical studies have shown that the technique of non-contact excimer laser PKP improves donor and recipient centration, reduces "vertical tilt" and "horizontal torsion" of the graft in the recipient bed, and thus results in significantly less "all-sutures-out" keratometric astigmatism (2.8 vs. 5.7 D), more regular topography (surface regularity index [SRI] 0.80 vs. 1.0) and better visual acuity (0.80 vs. 0.60), in comparison to the motor trephine. The stage of the disease does not influence functional outcome after excimer laser PKP. However, the refractive outcome of femtosecond laser keratoplasty resembles that with

  8. Comparison of Descemet Stripping Automated Endothelial Keratoplasty and Penetrating Keratoplasty in a Patient with Fuchs Endothelial Dystrophy

    Directory of Open Access Journals (Sweden)

    Alime Güneş

    2013-06-01

    Full Text Available To report a patient with Fuchs endothelial dystrophy (FED who underwent Descemet stripping automated endothelial keratoplasty (DSAEK on one eye and penetrating keratoplasty (PK on the fellow eye. A 74-year-old female patient with diagnosis of FED underwent uncomplicated cataract surgeries of both eyes, but developed bullous keratopathy eventually. The right eye underwent DSAEK and the left eye underwent PK. After 3 years of follow-up, the right eye had an uncorrected visual acuity (UCVA of 20/40 and best-corrected visual acuity (BCVA of 20/20 with spectacle correction (+2.25(-0.50x20°. Graft was clear with endothelial cell density (ECD of 1532 cells/mm2 (donor ECD was 3215 cells/mm2 and central corneal thickness (CCT was 674 µm. After 1 year of follow-up, the left eye had UCVA of 20/200, spectacle corrected (-3.50x100° visual acuity of 20/125, and BCVA of 20/40 with rigid contact lens correction. Graft was also clear with ECD of 1785 cells/mm2 (donor ECD was 3100 cells/mm2 and CCT was 610 : This case report represents the advantages and disadvantages of two surgical techniques (PK and DASEK applied on fellow eyes of a patient with FED (Turk J Ophthalmol 2013; 43: 202-4

  9. Visual rehabilitation using mini-scleral contact lenses after penetrating keratoplasty.

    Science.gov (United States)

    Rocha, Guilherme Andrade do Nascimento; Miziara, Patrícia Oliveira Braga; Castro, Ana Clara Vieira de; Rocha, Arthur Andrade do Nascimento

    2017-01-01

    To report the visual rehabilitation outcomes and complications of patients fitted with mini-scleral rigid gas-permeable (RGP) contact lenses (mini-SCLs) after penetrating keratoplasty. We retrospectively reviewed 27 eyes (21 patients) that were fitted with mini-SCLs between October 2013 and December 2014. We analyzed demographic data, previous corneal disorders, visual outcomes, interval from keratoplasty to contact lens fitting, topographic and specular microscope data, fitted contact lens parameters, and complications. The patients were divided into two groups according to the elapsed time since surgery: Group A, grafts with 8 D, and 1,231 ± 723 cells/mm2, respectively. Mini-SCL use allowed successful visual rehabilitation after corneal keratoplasty, particularly in patients who required corrective lenses for low visual acuity and were unable to wear RGP contact lenses. Our results indicate that mini-scleral lenses may be an option for the treatment of corneal irregularities, such as those associated with keratoplasty.

  10. [Rhegmatogenous retinal detachment in a patient with previous penetrating keratoplasty (clinical case)].

    Science.gov (United States)

    Burcea, M; Muşat, O; Gheorghe, Andreea; Mahdi, Labib; Colta, Diana; Cernat, Corina; Mansour, Agajani

    2014-01-01

    We present the case of a 54 year old patient diagnosed with rhegmatogenous retinal detachment and perforating keratoplasty. Surgery is recommended and we performed posterior vitrectomy, endolaser, and internal heavy oil tamponade. The post-operative course was favorable.

  11. A Feasibility Study of UV Laser Assisted 3D-Atom Probe Analysis of AlGaN/GaN HEMTs

    Science.gov (United States)

    2013-03-05

    Final Report for AOARD Grant-FA2386-11-1-4031 “A feasibility study of UV laser assisted 3D-atom probe analysis of AlGaN/ GaN HEMTs ” March 5...20-06-2011 to 19-06-2012 4. TITLE AND SUBTITLE A feasibility study of UV laser assisted 3D-atom probe analysis of AlGaN/ GaN HEMTs 5a. CONTRACT...gate region (gate metal, interfacial layer and defects, and AlGaN/ GaN epilayers) of an AFRL HEMT using laser assisted 3-D atom probe (3DAP

  12. A case of acute postoperative keratitis after deep anterior lamellar keratoplasty by multidrug resistant Klebsiella

    Directory of Open Access Journals (Sweden)

    Leena Bajracharya

    2015-01-01

    Full Text Available A healthy lady of 42 years underwent deep anterior lamellar keratoplasty for granular dystrophy. The very next day, it was complicated by development of infectious keratitis. The organism was identified as multidrug resistant Klebsiella pneumoniae. Donor corneal button may be implicated in the transmission of infection in an otherwise uneventful surgery and follow-up. Nosocomial infections are usually severe, rapidly progressive and difficult to treat. Finally, the lady had to undergo therapeutic penetrating keratoplasty for complete resolution of infection.

  13. Laser assisted die bending: a new application of high power diode lasers

    Science.gov (United States)

    Schuöcker, D.; Schumi, T.; Spitzer, O.; Bammer, F.; Schuöcker, G.; Sperrer, G.

    2015-02-01

    Nowadays high power lasers are mainly used for cutting of sheet metals, for welding, hardening and rapid prototyping. In the forming of sheet metals as bending or deep drawing lasers are not used. Nevertheless a few years ago a new application of high power lasers has been invented, where bending of materials that break at room temperature becomes possible by heating them along the bending edge with high power lasers thus allowing their treatment without cracks and rupture. For this purpose a large number of diode lasers are arranged in the bottom tool of a bending machine (a V-shaped die) which heat up the initially flat sheet metal during the bending process what is performed by pressing it into the die with a knife shaped upper tool where due to the laser heating the material is softened and thus cracks are avoided. For the technical realization of the new process of laser assisted die bending, modules equipped with numerous laser diodes and a total beam power of 2,5 kW are used. The light emitted by these modules enters a tool with a length of 15cm and is deflected towards the workpiece. By using ten of these modules with adjacent dies and by integrating those in a bending press a bending edge of sheet metals with a length of 1500mm can be realized. Such a bending press with laser assistance also needs energization with a power of practically 50kW, a respective water flow, a heat exchanger system and also a control for all functions of this system. Special measures have also been developed to avoid radiating of those tools that are not covered by a workpiece in the case of bending edges shorter than the full length of the bending tools whereas individual short circuiting of diode modules can be performed. Specific measures to ensure a safe operation without any harm to the operational person have been realized. Exploitation of the bending process has been carried out for titanium, where material thicknesses up to 3mm have been bent successfully.

  14. Ten-year postoperative results of penetrating keratoplasty.

    Science.gov (United States)

    Ing, J J; Ing, H H; Nelson, L R; Hodge, D O; Bourne, W M

    1998-10-01

    To investigate the changes in central corneal endothelial cells and corneal thickness in transplanted corneas from 5 to 10 years after grafting. This study also aimed to investigate the development of glaucoma, graft rejection, and graft failure during the first 10 postoperative years. Longitudinal cohort study of 500 consecutive penetrating keratoplasties by 1 surgeon. Patients were asked to return for follow-up examinations at 2 months and at 1, 3, 5, and 10 years after grafting. The authors excluded eyes regrafted during the study and the fellow eyes of bilateral cases, leaving 394 grafts in 394 patients for analysis. Penetrating keratoplasty was performed. Using specular microscopy, the authors measured endothelial cell density, coefficient of variation of cell area, percentage of hexagonal cells, and corneal thickness. The authors performed clinical examinations to determine graft rejection or failure and the development of glaucoma. By 10 years postkeratoplasty, 80 of the 394 patients had died and 68 grafts had failed. Of the remaining 246 patients, 119 (48%) returned for their 10-year examinations. For the 72 patients who returned for all of the scheduled postoperative visits and had no rejection episodes, reoperations, or failure, endothelial cell loss from preoperative donor levels at 10 years was 67 +/- 18% (mean +/- standard deviation), endothelial cell density was 958 +/- 471 cells/mm2, coefficient of variation was 0.32 +/- 0.11, hexagonal cells were 56 +/- 12%, and corneal thickness was 0.58 +/- 0.05 mm. The 5- to 10-year changes for all these values were significant (P risk of glaucoma, rejection, or failure was 21%, 21%, and 22%, respectively. Late endothelial failure became the major cause for graft failure, accounting for 9 of the 11 failures after 5 postoperative years. From 5 to 10 years after penetrating keratoplasty, the annual rate of endothelial cell loss was seven times the normal rate. The endothelial cell loss, pleomorphism, polymegethism

  15. Tunable femtosecond Cherenkov fiber laser

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Svane, Ask Sebastian; Lægsgaard, Jesper

    2014-01-01

    We demonstrate electrically-tunable femtosecond Cherenkov fiber laser output at the visible range. Using an all-fiber, self-starting femtosecond Yb-doped fiber laser as the pump source and nonlinear photonic crystal fiber link as the wave-conversion medium, ultrafast, milliwatt-level, tunable...... and spectral isolated Cherenkov radiation at visible wavelengths are reported. Such a femtosecond Cherenkov laser source is promising for practical biophotonics applications....

  16. Patterning of Endothelial Cells and Mesenchymal Stem Cells by Laser-Assisted Bioprinting to Study Cell Migration

    Directory of Open Access Journals (Sweden)

    Jean-Michel Bourget

    2016-01-01

    Full Text Available Tissue engineering of large organs is currently limited by the lack of potent vascularization in vitro. Tissue-engineered bone grafts can be prevascularized in vitro using endothelial cells (ECs. The microvascular network architecture could be controlled by printing ECs following a specific pattern. Using laser-assisted bioprinting, we investigated the effect of distance between printed cell islets and the influence of coprinted mesenchymal cells on migration. When printed alone, ECs spread out evenly on the collagen hydrogel, regardless of the distance between cell islets. However, when printed in coculture with mesenchymal cells by laser-assisted bioprinting, they remained in the printed area. Therefore, the presence of mesenchymal cell is mandatory in order to create a pattern that will be conserved over time. This work describes an interesting approach to study cell migration that could be reproduced to study the effect of trophic factors.

  17. Patterning of Endothelial Cells and Mesenchymal Stem Cells by Laser-Assisted Bioprinting to Study Cell Migration

    Science.gov (United States)

    Medina, Manuela; Rémy, Murielle; Thébaud, Noélie Brunehilde; Bareille, Reine; Chassande, Olivier; Amédée, Joëlle; Catros, Sylvain

    2016-01-01

    Tissue engineering of large organs is currently limited by the lack of potent vascularization in vitro. Tissue-engineered bone grafts can be prevascularized in vitro using endothelial cells (ECs). The microvascular network architecture could be controlled by printing ECs following a specific pattern. Using laser-assisted bioprinting, we investigated the effect of distance between printed cell islets and the influence of coprinted mesenchymal cells on migration. When printed alone, ECs spread out evenly on the collagen hydrogel, regardless of the distance between cell islets. However, when printed in coculture with mesenchymal cells by laser-assisted bioprinting, they remained in the printed area. Therefore, the presence of mesenchymal cell is mandatory in order to create a pattern that will be conserved over time. This work describes an interesting approach to study cell migration that could be reproduced to study the effect of trophic factors. PMID:27833916

  18. Laser-Assisted Simultaneous Transfer and Patterning of Vertically Aligned Carbon Nanotube Arrays on Polymer Substrates for Flexible Devices

    KAUST Repository

    In, Jung Bin

    2012-09-25

    We demonstrate a laser-assisted dry transfer technique for assembling patterns of vertically aligned carbon nanotube arrays on a flexible polymeric substrate. A laser beam is applied to the interface of a nanotube array and a polycarbonate sheet in contact with one another. The absorbed laser heat promotes nanotube adhesion to the polymer in the irradiated regions and enables selective pattern transfer. A combination of the thermal transfer mechanism with rapid direct writing capability of focused laser beam irradiation allows us to achieve simultaneous material transfer and direct micropatterning in a single processing step. Furthermore, we demonstrate that malleability of the nanotube arrays transferred onto a flexible substrate enables post-transfer tailoring of electric conductance by collapsing the aligned nanotubes in different directions. This work suggests that the laser-assisted transfer technique provides an efficient route to using vertically aligned nanotubes as conductive elements in flexible device applications. © 2012 American Chemical Society.

  19. Laser-assisted chemical vapor deposition setup for fast synthesis of graphene patterns

    Science.gov (United States)

    Zhang, Chentao; Zhang, Jianhuan; Lin, Kun; Huang, Yuanqing

    2017-05-01

    An automatic setup based on the laser-assisted chemical vapor deposition method has been developed for the rapid synthesis of graphene patterns. The key components of this setup include a laser beam control and focusing unit, a laser spot monitoring unit, and a vacuum and flow control unit. A laser beam with precision control of laser power is focused on the surface of a nickel foil substrate by the laser beam control and focusing unit for localized heating. A rapid heating and cooling process at the localized region is induced by the relative movement between the focalized laser spot and the nickel foil substrate, which causes the decomposing of gaseous hydrocarbon and the out-diffusing of excess carbon atoms to form graphene patterns on the laser scanning path. All the fabrication parameters that affect the quality and number of graphene layers, such as laser power, laser spot size, laser scanning speed, pressure of vacuum chamber, and flow rates of gases, can be precisely controlled and monitored during the preparation of graphene patterns. A simulation of temperature distribution was carried out via the finite element method, providing a scientific guidance for the regulation of temperature distribution during experiments. A multi-layer graphene ribbon with few defects was synthesized to verify its performance of the rapid growth of high-quality graphene patterns. Furthermore, this setup has potential applications in other laser-based graphene synthesis and processing.

  20. Laser-assisted atom probe tomography investigation of magnetic FePt nanoclusters: First experiments

    Energy Technology Data Exchange (ETDEWEB)

    Folcke, E.; Larde, R. [Groupe de Physique des Materiaux, UMR CNRS 6634, Universite de Rouen, 76801 Saint Etienne du Rouvray (France); Le Breton, J.M., E-mail: jean-marie.lebreton@univ-rouen.fr [Groupe de Physique des Materiaux, UMR CNRS 6634, Universite de Rouen, 76801 Saint Etienne du Rouvray (France); Gruber, M.; Vurpillot, F. [Groupe de Physique des Materiaux, UMR CNRS 6634, Universite de Rouen, 76801 Saint Etienne du Rouvray (France); Shield, J.E.; Rui, X. [Department of Mechanical and Materials Engineering, Nebraska Center for Materials and Nanoscience, University of Nebraska, N104 WSEC, Lincoln, NE 68588 (United States); Patterson, M.M. [Department of Physics, University of Wisconsin-Stout, Menomonie, WI 54751 (United States)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer FePt nanoclusters dispersed in a Cr matrix were studied by atom probe tomography. Black-Right-Pointing-Pointer Simulated experiments were conducted to study the artefacts of the analysis. Black-Right-Pointing-Pointer In FePt nanoclusters, Fe and Pt are present in equiatomic proportions. Black-Right-Pointing-Pointer FePt nanoclusters are homogeneous, no core-shell structure is observed. - Abstract: FePt nanoclusters dispersed in a Cr matrix have been investigated by laser-assisted atom probe tomography. The results were analysed according to simulated evaporation experiments. Three-dimensional (3D) reconstructions reveal the presence of nanoclusters roughly spherical in shape, with a size in good agreement with previous transmission electron microscopy observations. Some clusters appear to be broken up after the evaporation process due to the fact that the Cr matrix has a lower evaporation field than Fe and Pt. It is thus shown that the observed FePt nanoclusters are chemically homogeneous. They contain Fe and Pt in equiatomic proportions, with no core-shell structure observed.

  1. Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy.

    Science.gov (United States)

    Campanelli, Sabina Luisa; Casalino, Giuseppe; Casavola, Caterina; Moramarco, Vincenzo

    2013-12-18

    Friction Stir Welding (FSW) is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW) is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force.

  2. Guidable Thermophoretic Janus Micromotors Containing Gold Nanocolorifiers for Infrared Laser Assisted Tissue Welding.

    Science.gov (United States)

    He, Wenping; Frueh, Johannes; Hu, Narisu; Liu, Liping; Gai, Meiyu; He, Qiang

    2016-12-01

    Current wound sealing systems such as nanoparticle-based gluing of tissues allow almost immediate wound sealing. The assistance of a laser beam allows the wound sealing with higher controllability due to the collagen fiber melting which is defined by loss of tertiary protein structure and restoration upon cooling. Usually one employs dyes to paint onto the wound, if water absorption bands are absent. In case of strong bleeding or internal wounds such applications are not feasible due to low welding depth in case of water absorption bands, dyes washing off, or the dyes becoming diluted within the wound. One possible solution of these drawbacks is to use autonomously movable particles composing of biocompatible gold and magnetite nanoparticles and biocompatible polyelectrolyte complexes. In this paper a proof of principle study is presented on the utilization of thermophoretic Janus particles and capsules employed as dyes for infrared laser-assisted tissue welding. This approach proves to be efficient in sealing the wound on the mouse in vivo. The temperature measurement of single particle level proves successful photothermal heating, while the mechanical characterizations of welded liver, skin, and meat confirm mechanical restoration of the welded biological samples.

  3. Laser-assisted Zr/ZrO(2) coating on Ti for load-bearing implants.

    Science.gov (United States)

    Balla, Vamsi Krishna; Xue, Weichang; Bose, Susmita; Bandyopadhyay, Amit

    2009-09-01

    Oxidized Zr alloys have been shown to exhibit lower friction and superior wear properties, suggesting that they could be used in hip and knee implants. However, conventional oxidation of Zr alloys above 500 degrees C, in dry air, for several hours has been shown to have detrimental effects on the substrate's properties. In this work, we deposited pure Zr on Ti, then oxidized the coating using a continuous-wave Nd:YAG laser, which facilitated localized heating to elevated temperatures without affecting the substrate. Laser-assisted oxidation resulted in a 7microm thick fully dense ZrO(2) layer on Zr in which an increase in oxidation kinetics was evident due to an increase in the laser power and/or the oxygen partial pressure. Due to its high surface energy and wettability, the wear rate of laser-oxidized Zr was two orders of magnitude less compared to that of as-deposited Zr. The oxidized coatings showed comparable in vitro biocompatibility to that of pure Ti and excellent in vitro cell-material interactions. This article reports the processing of Zr/ZrO(2) coatings on Ti using lasers, and the influence of laser parameters and oxygen partial pressure on the coating's mechanical, microstructural, wear and in vitro biological properties using human osteoblast cells.

  4. Laser-Assisted Semi Relativistic Excitation of Atomic Hydrogen by Electronic Impact

    CERN Document Server

    Taj, S; Idrissi, M El; Oufni, L

    2012-01-01

    The excitation of H ($1s-2s$) by electron impact in the presence and in the absence of the laser field is studied in the framework of the first Born approximation. The angular variation of the laser-assisted differential cross section (DCS) for atomic hydrogen by electronic impact is presented at various kinetic energies for the incident electron. The use of Darwin wave function as a semirelativistic state to represent the atomic hydrogen gives interesting results when the condition $z/c\\ll1$ is fulfilled. A comparison with the non relativistic theory and experimental data gives good agreement. It was observed that beyond (2700 $eV$) which represents the limit between the two approaches, the non relativistic theory does not yield close agreement with our theory and that, over certain ranges of energy, it can be in error by several orders of magnitude. The sum rule given by Bunkin and Fedorov and by Kroll and Watson \\cite{22} has been verified in both nonrelativistic and relativistic regimes.

  5. Sentinel Lymph Node Detection Using Laser-Assisted Indocyanine Green Dye Lymphangiography in Patients with Melanoma

    Directory of Open Access Journals (Sweden)

    Vikalp Jain

    2013-01-01

    Full Text Available Introduction. Sentinel lymph node (SLN biopsy is a vital component of staging and management of multiple cancers. The current gold standard utilizes technetium 99 (tech99 and a blue dye to detect regional nodes. While the success rate is typically over 90%, these two methods can be inconclusive or inconvenient for both patient and surgeon. We evaluated a new technique using laser-assisted ICG dye lymphangiography to identify SLN. Methods. In this retrospective analysis, we identified patients with melanoma who were candidates for SLN biopsy. In addition to tech99 and methylene blue, patients received a dermal injection of indocyanine green (ICG. The infrared signal was detected with the SPY machine (Novadaq, and nodes positive by any method were excised. Results. A total of 15 patients were evaluated, with 40 SLNs removed. Four patients were found to have nodal metastases on final pathology. 100% of these 4 nodes were identified by ICG, while only 75% (3/4 were positive for tech99 and/or methylene blue. Furthermore, none of the nodes missed by ICG (4/40 had malignant cells. Conclusion. ICG dye lymphangiography is a reasonable alternative for locating SLNs in patients with melanoma. Prospective studies are needed to better ascertain the full functionality of this technique.

  6. Vitreoretinal surgery for macular hole after laser assisted in situ keratomileusis for the correction of myopia

    Science.gov (United States)

    Arevalo, J F; Rodriguez, F J; Rosales-Meneses, J L; Dessouki, A; Chan, C K; Mittra, R A; Ruiz-Moreno, J M

    2005-01-01

    Ams: To describe the characteristics and surgical outcomes of full thickness macular hole surgery after laser assisted in situ keratomileusis (LASIK) for the correction of myopia. Methods: 13 patients (14 eyes) who developed a macular hole after bilateral LASIK for the correction of myopia participated in the study. Results: Macular hole formed 1–83 months after LASIK (mean 13 months). 11 out of 13 (84.6%) patients were female. Mean age was 45.5 years old (25–65). All eyes were myopic (range −0.50 to −19.75 dioptres (D); mean −8.4 D). Posterior vitreous detachment (PVD) was not present before and was documented after LASIK on 42.8% of eyes. Most macular hole were unilateral, stage 4 macular hole, had no yellow deposits on the retinal pigment epithelium, had no associated epiretinal membrane, were centric, and had subretinal fluid. The mean diameter of the hole was 385.3 μm (range 200–750 μm). A vitrectomy closed the macular hole on all eyes with an improvement on final best corrected visual acuity (VA) on 13 out of 14 (92.8%) patients. Conclusions: This study shows that vitreoretinal surgery can be successful in restoring vision for most myopic eyes with a macular hole after LASIK. PMID:16234445

  7. Laser-assisted Stark deceleration of polar diatomic molecules in the Χ1Σ state

    Science.gov (United States)

    Huang, Yunxia; Xu, Shuwu; Yang, Xiaohua

    2016-07-01

    The traditional Stark deceleration method is difficult to apply in chemically stable polar diatomic molecules in their ground (Χ1Σ) state because the Χ1Σ state normally experiences little Stark shift and the rovibronic ground level is mostly high-field-seeking. To solve this problem, we propose a laser-assisted Stark deceleration scheme to decelerate such molecules in the present paper. Our results show that, owing to the transverse bunching effect of the applied red-detuning laser beam, the molecules of the high-field-seeking level |J = 0, M = 0> in the Χ1Σ state can be effectively decelerated. Furthermore, the present scheme is more effective because the interaction between the molecules and the combined fields can produce the pseudo-first-order Stark effect, and thus increase the depth of the effective potential. Compared to those molecules in the low-field-seeking state |J = 1, MΩ = -1> in the usual electrostatic Stark deceleration, a higher molecular density and lower velocity can be achieved under an equivalent initial phase angle.

  8. Long-term efficacy of microbiology-driven periodontal laser-assisted therapy.

    Science.gov (United States)

    Martelli, F S; Fanti, E; Rosati, C; Martelli, M; Bacci, G; Martelli, M L; Medico, E

    2016-03-01

    Periodontitis represents a highly prevalent health problem, causing severe functional impairment, reduced quality of life and increased risk of systemic disorders, including respiratory, cardiovascular and osteoarticular diseases, diabetes and fertility problems. It is a typical example of a multifactorial disease, where a polymicrobial infection inducing chronic inflammation of periodontal tissues is favoured by environmental factors, life style and genetic background. Since periodontal pathogens can colonise poorly vascularised niches, antiseptics and antibiotics are typically associated with local treatments to manage the defects, with unstable outcomes especially in early-onset cases. Here, the results of a retrospective study are reported, evaluating the efficacy of a protocol (Periodontal Biological Laser-Assisted Therapy, Perioblast™) by which microbial profiling of periodontal pockets is used to determine the extent and duration of local neodymium-doped yttrium aluminium garnet (Nd:YAG) laser irradiation plus conventional treatment. The protocol was applied multicentrically on 2683 patients, and found to produce a significant and enduring improvement of all clinical and bacteriological parameters, even in aggressive cases. Microbiome sequencing of selected pockets revealed major population shifts after treatment, as well as strains potentially associated with periodontitis in the absence of known pathogens. This study, conducted for the first time on such a large series, clearly demonstrates long-term efficacy of microbiology-driven non-invasive treatment of periodontal disease.

  9. Laser-assisted photothermal heating of a plasmonic nanoparticle-suspended droplet in a microchannel.

    Science.gov (United States)

    Walsh, Timothy; Lee, Jungchul; Park, Keunhan

    2015-03-07

    The present article reports the numerical and experimental investigations on the laser-assisted photothermal heating of a nanoliter-sized droplet in a microchannel when plasmonic particles are suspended in the droplet. Plasmonic nanoparticles exhibit strong light absorption and scattering upon the excitation of localized surface plasmons (LSPs), resulting in intense and rapid photothermal heating in a microchannel. Computational models are implemented to theoretically verify the photothermal behavior of gold nanoshell (GNS) and gold nanorod (GNR) particles suspended in a liquid microdroplet. Experiments were conducted to demonstrate rapid heating of a sub-100 nL droplet up to 100 °C with high controllability and repeatability. The heating and cooling time to the steady state is on the order of 1 second, while cooling requires less time than heating. The effects of core parameters, such as nanoparticle structure, volumetric concentration, microchannel depth, and laser power density on heating are studied. The obtained results can be integrated into existing microfluidic technologies that demand accurate and rapid heating of microdroplets in a microchannel.

  10. Indoor radiation mapping using the Laser Assisted Ranging and Data System (LARADS). Innovative technology summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-11-01

    The US Department of Energy`s (DOE`s) nuclear facilities require characterization and documentation of the results as part of planning and decision-making for decontamination and decommissioning (D and D) projects and to release areas that have been cleaned up. Conducting radiation surveys of indoor and outdoor surfaces and generating accurate survey reports is an important component of the D and D program. The Laser Assisted Ranging and Data System (LARADS) is a characterization technology that provides real-time data on the location and concentration levels of radiological contamination. The system can be utilized with a number of available detection instruments and can be integrated with existing data analysis and mapping software technologies to generate superior quality survey data reports. This innovative technology is competitive with baseline technologies in terms of cost and survey times, but is much more flexible and provides more useful reports. The system also has the capability of electronically logging survey data, making it easy to store and retrieve. Such data are scientifically derived and not subject to interpretation. The LARADS is an extremely attractive alternative to manually generated survey data reports.

  11. En-face OCT microleakage investigation after laser-assisted dental hard tissue treatment

    Science.gov (United States)

    Todea, Carmen; Balabuc, Cosmin; Sinescu, Cosmin; Negrutiu, Meda; Filip, Laura; Bradu, Adrian; Podoleanu, Adrian Gh.

    2008-09-01

    Purpose: To investigate using en-face Optical Coherence Tomography (OCT) the microleakage after Er:YAG laser cavity preparation. Material and Methods: Thirty single- and multi-rooted freshly extracted human teeth divided into two study groups, group I (laser) and group II (control), were used in this study. In group I, Class V cavities were prepared using laser on the buccal surface of each tooth. The laser device used was an Er:YAG laser (2940 nm, VSP, 250-320 mJ, 10-20 Hz). In group II, cavities were prepared conventionally and acid etched on the oral surface of the same tooth. All cavities were filled with composite resin. The cavity microleakage was investigated using en-face Optical Coherence Tomography prototype, based on transverse scanning and operating at 1300 nm. Results: The investigation demonstrated qualitatively the reduction of microleakage in cavities prepared with Er:YAG laser as compared to the control group, in which cavities were prepared conventionally. Conclusion: The en-face OCT method provided a superior non-invasive and real time investigation method, thus reducing the occurrence of secondary caries by early detection. Moreover, based on the results of this investigation, it may be concluded that Er:YAG laser-assisted cavity preparation leads to reduction of microleakage.

  12. Corneal Deposit of Ciprofloxacin after Laser Assisted Subepithelial Keratomileusis Procedure: A Case Report

    Directory of Open Access Journals (Sweden)

    Giacomo De Benedetti

    2010-01-01

    Full Text Available Purpose. To report one case of corneal antibiotic deposition after ciprofloxacin administration in Laser Assisted Subepithelial Keratomileusis (LASEK. Methods. One case of post-LASEK treatment resulted in corneal precipitates and poor wound healing. Debris was analyzed with dark field microscopy and placed on a blood-agar plate seeded with a susceptible stain of Staphylococcus aureus (ATCC 29213. Results. The alterations resolved with discontinuation of ciprofloxacin treatment, although some residual deposits persisted subepithelially for 6 months. Analysis of precipitates revealed polydisperse crystalline needles of 183 m average length (SD=54 m and the excised precipitate demonstrated a zone of inhibition. Conclusions. Fluoroquinolone antibiotic drops have been used extensively in postsurgical treatment of refractive surgery. Corneal precipitates have been previously reported in the literature, but up to now nothing has been documented after LASEK. Polypharmacy during refractive surgery may impair epithelialisation, and clinical management should reduce toxic environment and promote ocular surface stability when performing surface ablations.

  13. Self-assembled germanium nano-structures by laser-assisted oxidation

    Institute of Scientific and Technical Information of China (English)

    Huang Wei-Qi; Liu Shi-Rong

    2006-01-01

    The investigation on the oxidation behaviour of Si1-xGex; alloys (x=0.05, 0.15, and 0.25) is carried out. It is found for the first time that on the oxide film a germanium nano-cap with a thickness of 1.8ranging from 5.5 nm to 10 nm are formed by the low-temperature laser-assisted dry oxidation of Si1-xGex substrate. A new scanning method on the decline cross-section of the multiple-layer sample is adopted to measure the layer thickness and the composition. Some new peaks in photoluminescence (PL) spectra are discovered, which could be related to the nano-cap and the nano-particles of germanium. A suitable model and several new calculating formulae with the unrestricted Hartree-Fock-Roothaan (UHFR) method and quantum confinement analysis are proposed to interpret the PL spectra and the nano-structure mechanism in the oxide.

  14. The effect of bound state dressing in laser assisted radiative recombination

    CERN Document Server

    Müller, Robert Alexander; Fritzsche, Stephan; Surzhykov, Andrey

    2015-01-01

    We present a theoretical study on the recombination of a free electron into the ground state of a hydrogen-like ion in the presence of an external laser field. Emphasis is placed on the effects caused by the laser dressing of the residual ionic bound state. To investigate how this dressing affects the total and angle-differential cross section of laser assisted radiative recombination (LARR) we apply first-order perturbation theory and the separable Coulomb-Volkov-continuum ansatz. Using this approach detailed calculations were performed for low-$Z$ hydrogen like ions and laser intensities in the range from $I_L=10^{11}\\text{W/cm}^2$ to $I_L=10^{13}\\text{W/cm}^2$. It is seen that the total cross section as a function of the laser intensity is remarkably affected by the bound state dressing. Moreover the laser dressing becomes manifest as asymmetries in the angular distribution and the (energy) spectrum of the emitted recombination photons.

  15. Laser-assisted synthesis of diamond crystals in open air through vibrational excitation of precursor molecules

    Science.gov (United States)

    Xie, Z. Q.; Zhou, Y. S.; He, X. N.; Gao, Y.; Park, J. B.; Guillemet, T.; Lu, Y. F.

    2011-03-01

    Fast growth of diamond crystals in open air was achieved by laser-assisted combustion synthesis through vibrational excitation of precursor molecules. A wavelength-tunable CO2 laser (spectrum range from 9.2 to 10.9 μm) was used for the vibrational excitation in synthesis of diamond crystals. A pre-mixed C2H4/C2H2/O2 gas mixture was used as precursors. Through resonant excitation of the CH2-wagging mode of ethylene (C2H4) molecules using the CO2 laser tuned at 10.532 Μm, high-quality diamond crystals were grown on silicon substrates with a high growth rate of ~139 μm/hr. Diamond crystals with a length up to 5 mm and a diameter of 1 mm were grown in 36 hours. Sharp Raman peaks at 1332 cm-1 with full width at half maximum (FWHM) values around 4.5 cm-1 and distinct X-ray diffraction spectra demonstrated the high quality of the diamond crystals. The effects of the resonant excitation of precursor molecules by the CO2 laser were investigated using optical emission spectroscopy.

  16. Preparation of nanowire specimens for laser-assisted atom probe tomography.

    Science.gov (United States)

    Blumtritt, H; Isheim, D; Senz, S; Seidman, D N; Moutanabbir, O

    2014-10-31

    The availability of reliable and well-engineered commercial instruments and data analysis software has led to development in recent years of robust and ergonomic atom-probe tomographs. Indeed, atom-probe tomography (APT) is now being applied to a broader range of materials classes that involve highly important scientific and technological problems in materials science and engineering. Dual-beam focused-ion beam microscopy and its application to the fabrication of APT microtip specimens have dramatically improved the ability to probe a variety of systems. However, the sample preparation is still challenging especially for emerging nanomaterials such as epitaxial nanowires which typically grow vertically on a substrate through metal-catalyzed vapor phase epitaxy. The size, morphology, density, and sensitivity to radiation damage are the most influential parameters in the preparation of nanowire specimens for APT. In this paper, we describe a step-by-step process methodology to allow a precisely controlled, damage-free transfer of individual, short silicon nanowires onto atom probe microposts. Starting with a dense array of tiny nanowires and using focused ion beam, we employed a sequence of protective layers and markers to identify the nanowire to be transferred and probed while protecting it against Ga ions during lift-off processing and tip sharpening. Based on this approach, high-quality three-dimensional atom-by-atom maps of single aluminum-catalyzed silicon nanowires are obtained using a highly focused ultraviolet laser-assisted local electrode atom probe tomograph.

  17. Laser-assisted friction stir welding of aluminum alloy lap joints: microstructural and microhardness characterizations

    Science.gov (United States)

    Casalino, Giuseppe; Campanelli, Sabina L.; Contuzzi, Nicola; Angelastro, Andrea; Ludovico, Antonio D.

    2014-02-01

    Friction Stir Welding (FSW) is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. The laser Assisted Friction Stir Welding (LAFSW) combines a Friction Stir Welding machine and a laser system. Laser power is used to preheat and to plasticize the volume of the workpiece ahead of the rotating tool; the workpiece is then joined in the same way as in the conventional FSW process. In this work an Ytterbium fiber laser with maximum power of 4 kW and a commercial FSW machine were coupled. Both FSW and LAFSW tests were conducted on 3 mm thick 5754H111 aluminum alloy plates in lap joint configuration with a constant tool rotation rate and with different feed rates. The two processes were compared and evaluated in terms of differences in the microstructure and in the micro-hardness profile.

  18. Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Sabina Luisa Campanelli

    2013-12-01

    Full Text Available Friction Stir Welding (FSW is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force.

  19. Histologic evaluation of an Nd:YAG laser-assisted new attachment procedure in humans.

    Science.gov (United States)

    Yukna, Raymond A; Carr, Ronald L; Evans, Gerald H

    2007-12-01

    This report presents histologic results in humans following a laser-assisted new attachment procedure (LANAP) for the treatment of periodontal pockets. Six pairs of single-rooted teeth with moderate to advanced chronic periodontitis associated with subgingival calculus deposits were treated. A bur notch was placed within the pocket at the clinically and radiographically measured apical extent of calculus. All teeth were scaled and root planed with ultrasonic and hand scalers. One of each pair of teeth received treatment of the inner pocket wall with a free-running pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser to remove the pocket epithelium, and the test pockets were lased a second time to seal the pocket. After 3 months, all treated teeth were removed en bloc for histologic processing. LANAP-treated teeth exhibited greater probing depth reductions and clinical probing attachment level gains than the control teeth. All LANAP-treated specimens showed new cementum and new connective tissue attachment in and occasionally coronal to the notch, whereas five of the six control teeth had a long junctional epithelium with no evidence of new attachment or regeneration. There was no evidence of any adverse histologic changes around the LANAP specimens. These cases support the concept that LANAP can be associated with cementum-mediated new connective tissue attachment and apparent periodontal regeneration of diseased root surfaces in humans.

  20. Natural guide-star processing for wide-field laser-assisted AO systems

    CERN Document Server

    Correia, Carlos M; Conan, Jean-Marc; Petit, Cyril; Sauvage, Jean-Francois; Fusco, Thierry; Vernet, Joel D R; Thatte, Niranjan

    2016-01-01

    Sky-coverage in laser-assisted AO observations largely depends on the system's capability to guide on the faintest natural guide-stars possible. Here we give an up-to-date status of our natural guide-star processing tailored to the European-ELT's visible and near-infrared (0.47 to 2.45 {\\mu}m) integral field spectrograph - Harmoni. We tour the processing of both the isoplanatic and anisoplanatic tilt modes using the spatio-angular approach whereby the wave-front is estimated directly in the pupil plane avoiding a cumbersome explicit layered estimation on the 35-layer profiles we're currently using. Taking the case of Harmoni, we cover the choice of wave-front sensors, the number and field location of guide-stars, the optimised algorithms to beat down angular anisoplanatism and the performance obtained with different temporal controllers under split high-order/low-order tomography or joint tomography. We consider both atmospheric and far greater telescope wind buffeting disturbances. In addition we provide the...

  1. Evaluation of Laser-Assisted Trans-Nail Drug Delivery with Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Meng-Tsan Tsai

    2016-12-01

    Full Text Available The nail provides a functional protection to the fingertips and surrounding tissue from external injuries. The nail plate consists of three layers including dorsal, intermediate, and ventral layers. The dorsal layer consists of compact, hard keratins, limiting topical drug delivery through the nail. In this study, we investigate the application of fractional CO2 laser that produces arrays of microthermal ablation zones (MAZs to facilitate drug delivery in the nails. We utilized optical coherence tomography (OCT for real-time monitoring of the laser–skin tissue interaction, sparing the patient from an invasive surgical sampling procedure. The time-dependent OCT intensity variance was used to observe drug diffusion through an induced MAZ array. Subsequently, nails were treated with cream and liquid topical drugs to investigate the feasibility and diffusion efficacy of laser-assisted drug delivery. Our results show that fractional CO2 laser improves the effectiveness of topical drug delivery in the nail plate and that OCT could potentially be used for in vivo monitoring of the depth of laser penetration as well as real-time observations of drug delivery.

  2. femtosecond laser ablation

    OpenAIRE

    Margetic, Vanja

    2003-01-01

    Femtosecond laser ablation was investigated as a solid sampling method for elemental chemical analysis. In comparison to the sampling with longer laser pulses, two aspects could be improved by using ultrashort pulses: elimination of the elemental fractionation from the ablation crater, which is necessary for an accurate quantitative analysis, and better control of the material removal (especially for metals), which increases the spatial resolution of microanalysis. Basic aspects of ultrashort...

  3. Morphological changes in corneal endothelial cells after penetrating keratoplasty.

    Science.gov (United States)

    Laing, R A; Sandstrom, M; Berrospi, A R; Leibowitz, H M

    1976-09-01

    Fifteen patients who had had a successful penetrating keratoplasty were photographed with the clinical specular microscope and the resulting endothelial photomicrographs were analyzed. The average endothelial cell area was one to six times larger and the average endothelial cell perimeter was one to 2 1/2 times larger than that of a normal cornea of a subject the same age as the donor. In each corneal graft, endothelial cell areas and perimeters clustered tightly around a mean value, although the mean value for different corneas varied significantly. The thickness and transparency of each graft was normal, indicating that within the observed limits the success of the transplantation procedure did not depend on final endothelial cell size or perimeter.

  4. Can we overcome the challenges of sutures in lamellar keratoplasty?

    Directory of Open Access Journals (Sweden)

    Anita Panda

    2011-01-01

    Full Text Available Lamellar keratoplasty (LK is a technique which can be followed for both tectonic and optical purposes. We describe a technique of sutureless anterior LK by fixing the donor lenticule to the recipient bed using fibrin glue. LK was performed in an eye with corneal opacity using the manual dissection method. The donor lenticule was cut with a microkeratome after fixing the corneoscleral rim in an artificial anterior chamber. The size of the donor lenticule was 8.5 mm and fixed to the recipient bed with fibrin glue. The surgical time was reduced significantly with this technique. There was an uneventful postoperative period during the follow-up of 12 months. Best corrected visual acuity improved from hand movement to 20/60. Thus, the use of fibrin glue for fixing the anterior lamellar lenticule is a viable option for both optical and anatomical purposes.

  5. Current Approaches for Management of Postpenetrating Keratoplasty Astigmatism

    Directory of Open Access Journals (Sweden)

    Sepehr Feizi

    2011-01-01

    Full Text Available A successful corneal graft requires both clarity and an acceptable refraction. A clear corneal graft may be an optical failure if high astigmatism limits visual acuity. Intraoperative measures to reduce postkeratoplasty astigmatism include round and central trephination of cornea with an adequate size, appropriate sutures with evenly distributed tension, and perfect graft-host apposition. Suture manipulation has been described for minimising early postoperative astigmatism. If significant astigmatism remains after suture removal, which cannot be corrected by optical means, then further surgical procedures containing relaxing incisions, compression sutures, laser refractive surgery, insertion of intrastromal corneal ring segments, wedge resection, and toric intraocular lens implantation can be performed. When astigmatism cannot be reduced using one or more abovementioned approaches, repeat penetrating keratoplasty should inevitably be considered. However, none of these techniques has emerged as an ideal one, and corneal surgeons may require combining two or more approaches to exploit the maximum advantages.

  6. Study of Pulse Laser Assisted Metalorganic Vapor Phase Epitaxy of InGaN with Large Indium Mole Fraction

    Science.gov (United States)

    Kangawa, Yoshihiro; Kawaguchi, Norihito; Hida, Ken-nosuke; Kumagai, Yoshinao; Koukitu, Akinori

    2004-08-01

    The indium composition of the InGaN film increases with decreasing growth temperature; however, the crystalline quality of the film is poor when it is grown at low temperatures. To form a high-quality InGaN film with a large indium mole fraction, Nd: YAG pulse laser assisted metalorganic vapor phase epitaxy (MOVPE) was carried out at low temperatures. The results suggest that film quality can be improved by pulse laser irradiation on the surface of the film.

  7. Effect of laser-assisted bleaching with Nd:YAG and diode lasers on shear bond strength of orthodontic brackets.

    Science.gov (United States)

    Mirhashemi, Amirhossein; Emadian Razavi, Elham Sadat; Behboodi, Sara; Chiniforush, Nasim

    2015-12-01

    The aim of the present study was to assess the effect of laser-assisted bleaching with neodymium:yttrium-aluminum-garnet (Nd:YAG) and diode lasers on shear bond strength (SBS) of orthodontic brackets. One hundred and four extracted human premolars were randomly divided into four groups: group 1: No bleaching applied (control group); group 2: Teeth bleached with 40 % hydrogen peroxide; group 3: Teeth treated with 30 % hydrogen peroxide activated with Nd:YAG laser (1064 nm, 2.5 W, 25 Hz, pulse duration of 100 μs, 6 mm distance); and group 4: Teeth treated with 30 % hydrogen peroxide activated with diode laser (810 nm, 1 W, CW, 6 mm distance). Equal numbers of teeth in groups 2, 3, and 4 were bonded at start, 1 h, 24 h, and 1 week after bleaching. A universal testing machine measured the SBS of the samples 24 h after bonding. After bracket debonding, the amount of residual adhesive on the enamel surface was observed under a stereomicroscope to determine the adhesive remnant index (ARI) scores. The SBS in the unbleached group was significantly higher than that in the bleached groups bonded immediately and 1 h after laser-assisted bleaching (P laser-assisted bleaching, the SBS was found to be significantly lower than that in the control group. Significant differences in the ARI scores existed among groups as well. The SBS of brackets seems to increase quickly within an hour after laser-assisted bleaching and 24 h after conventional bleaching. Thus, this protocol can be recommended if it is necessary to bond the brackets on the same day of bleaching.

  8. Comparison of contrast sensitivity and visual acuity between deep anterior lamellar keratoplasty and penetrating keratoplasty in patients with keratoconus

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    Mehmet Orcun Akdemir

    2012-12-01

    Full Text Available AIM: To evaluate postoperative visual acuity and contrast sensitivity results following deep anterior lamellar keratoplasty (DALK and penetrating keratoplasty (PK in patients with keratoconus (KC. METHODS: All the patients’ records with KC who had PK or DALK surgery between May 2010 and May 2011 were retrospectively reviewed. Sixty patients who underwent successful corneal transplantation for KC: 30 eyes underwent DALK and 30 eyes underwent PK were included in this study. Preoperative and postoperative mean logarithm of the minimum angle of resolution (logMAR uncorrected visual acuity (UCVA, logMAR best spectacle-corrected visual acuity (BSCVA and intraocular pressure (IOP were evaluated. Contrast sensitivity tests (CS were done preoperative and 2 months after all sutures had removed. All surgeries were performed under regional anesthesia (retrobulbar anesthesia by 1 surgeon (B.K. who was experienced in penetrating and lamellar keratoplasty techniques.RESULTS: The mean age of the DALK group was 29.67±4.95 (range 18-40 years and the PK group was 28.7±3.53 (range 18-39 years. Preoperatively there was no significant difference in the logMAR UCVA, logMAR BSCVA and IOP between the DALK (1.281±0.56; 0.97±0.85; 12.07±2.12mmHg and PK (1.34±0.21; 0.98±0.21; 13±2.12mmHg groups. One-year after surgery there was no significant difference in the mean logMAR UCVA and IOP between the DALK (0.46±0.37; 11.73±2.1mmHg and PK (0.38±0.21; 12±2.12mmHg groups. The mean contrast sensitivity was evaluated by CC-100 Topcon LCD at 1.5, 2.52, 4.23, 7.10 and 11.91 cycles per degree (cs/deg spatial frequencies before and 2 months after the all sutures had removed. CONCLUSION: All patients with keratoconus in both DALK and PK groups performed good visual function postoperatively. The mean contrast sensitivity increased considerably at all spatial frequencies compared with preoperative levels in the DALK and PK groups. The mean post-operative evaluation of

  9. Outcomes of Penetrating Keratoplasty for Macular Corneal Dystrophy

    Science.gov (United States)

    Karimian, Farid; Baradaran-Rafii, Ali-Reza; Feizi, Sepehr; Zare, Mohammad; Jafarinasab, Mohammad-Reza; Javadi, Mohammad-Ali; Mirdehghan, S. Ali; Einollahi, Bahram

    2009-01-01

    Purpose To report the outcomes of penetrating keratoplasty (PKP) in patients with macular corneal dystrophy (MCD). Methods This retrospective case series includes consecutive patients with MCD who underwent PKP from 1986 to 2006 with at least 6 months’ follow-up. Main outcome measures included best spectacle-corrected visual acuity (BSCVA), postoperative astigmatism and graft survival. Results Sixty-two eyes of 39 patients with mean age of 34.0±10.5 (range 13–58) years at the time of keratoplasty were included for analysis. After a mean follow-up period of 52.0±47.3 (range 6–190) months, BSCVA improved from 1.4±0.4 logMAR (4/100) preoperatively to 0.2±0.3 logMAR (20/32) at final follow-up (P<0.001).Mean postoperative BSCVA was 0.15±0.40 logMAR in patients (36 eyes) aged less than 35 years at the time of surgery as compared to 0.26±0.25 logMAR in subjects (26 eyes) older than 35 years (P=0.005). Final astigmatism was comparable with different suturing techniques including separate, continuous, and combined sutures (P=0.9). All grafts were clear at final follow-up except a single case of MCD with visually insignificant recurrence.Episodes of immunologic graft rejection occurred in 12 eyes (19.4%) but none led to graft failure. Conclusion PKP for MCD entails favorable outcomes in terms of graft survival and visual improvement. Final visual acuity seems to be better when transplantation is performed before the age of 35 years. PMID:23056668

  10. [Emergency Keratoplasty with Porcine Xenografts in Necrotizing Keratitis].

    Science.gov (United States)

    Drozhzhyna, Galyna I; Gaidamaka, Tetiana B; Cursiefen, Claus; Bachmann, Björn O; Ivanovska, Olena V; Ostashevsky, Viktor L; Kogan, Boris M; Usov, Volodymyr J; Pasyechnikova, Natalija V

    2017-07-06

    Background The great shortage of donor material in Ukraine makes it necessary to find additional sources of transplant material. A possible suitable material are the porcine corneas, as they are similar in structure and biomechanical parameters to the human cornea. The purpose of our study was to analyze the results of therapeutic keratoplasty (KP) with keratoxenotransplants from cryolyophilized porcine corneas in patients with severe necrotizing keratitis. Methods A retrospective analysis of 32 xenotransplantations patients with severe necrotizing keratitis (17 lamellar, 6 stepped perforating, 4 perforating, 5 "biological coverage" according to Puchkovskaya) was completed. Results All eyes could be preserved, but the graft was rejected in all eyes. A semitransparent xenograft (XG) was achieved in 9 patients (33.3%). The best results were obtained after lamellar XKP with an XT diameter of 3.5 - 6.5 mm. Lamellar XTs with larger diameters (7.0 - 10.0 mm) were opaque. Postoperatively, the intensity of the inflammatory response after stepped XKP was slightly lower than that of the classical perforating XKP. A new KP with human corneas had to be performed in 5 patients, in one case combined with an antiglaucomatous operation and in another case with cataract extraction. Antiglaucomatous surgery had to be performed in 5 patients (15.6%). Conclusion In the absence of human donor corneas, a porcine keratoxenoimplant can be used as temporary therapeutic keratoplasty in case of emergency stop the inflammation process and to save the eye. In cases of keratoxenoimplant, a poor visual outcome is expected. Georg Thieme Verlag KG Stuttgart · New York.

  11. Novel spatula and dissector for safer deep anterior lamellar keratoplasty

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    Gustavo ,2,3 Bonfadini

    2014-10-01

    Full Text Available Objective: We describe a novel spatula and dissector to facilitate the big-bubble technique in deep anterior lamellar keratoplasty (DALK. Methods: A 29-year-old man who was diagnosed with bilateral keratoconus underwent deep anterior lamellar keratoplasty (DALK. After 350μm partial thickness incision of the recipient cornea, the Bonfadini dissector was inserted at the deepest point in the peripheral incision and could be advanced to the center of the cornea safely because of its "semi-sharp" tip. After achieving the big-bubble (BB separation of Descemet membrane (DM from the overlying stroma, the anterior stromal disc was removed. Viscoelastic material was placed on the stromal bed to prevent uncontrolled collapse and perforation of DM during the paracentesis blade incision into the BB. We could detect the safe opening of the BB using the Bonfadini dissector by the leakage of air bubbles into the viscoelastic material. After injecting viscoelastic material into the BB space, we inserted the Bonfadini spatula into the bigbubble safely because of its curved profile and blunt edges. The groove along the length of the Bonfadini spatula enables safe and efficient incision or the residual stromal tissue using the pointed end of a sharp blade while protecting the underlying DM. After removal of posterior stroma, the donor button was sutured with 16 interrupted 10-0 nylon sutures. Results: This technique and the use of the Bonfadini spatula and dissector facilitate exposure of Descemet membrane. Conclusion: The smooth Bonfadini DALK spatula and dissector facilitate safe and efficient completion of DALK surgery.

  12. Complications and Management of Deep Anterior Lamellar Keratoplasty

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    Banu Torun Acar

    2014-10-01

    Full Text Available Objectives: To report the intraoperative and postoperative follow-up complications and management of these in deep anterior lamellar keratoplasty (DALK surgery. Materials and Methods: Two hundred eighty-four eyes of 252 patients followed up in our cornea clinic who underwent DALK using Anwar’s big-bubble technique with healthy Descemet’s membrane and endothelium were included in this study. Intraoperative and postoperative complications as well as the management and treatment of these complications were evaluated. Results: Big bubble was created in 220 (77.5% eyes of 284 eyes, and lamellar dissection was performed in 64 (22.5% eyes. Perforation occurred during trephination in 4 eyes, and the procedure was accomplished by penetrating keratoplasty (PK. Intraoperative microperforation occurred in 44 eyes. Perforation enlarged in 4 eyes and PK was performed. Operation was continued in 40 eyes with air injection into the anterior chamber. In postopertive follow-up period, double anterior chamber (DAC occurred in 32 of 40 eyes. DAC spontaneously regressed in 8 eyes, and air was given into the anterior chamber with a second surgical intervention in 24 eyes. DAC improved in 20 eyes. Four eyes underwent PK. Fungal keratitis evolved at the interface in one eye, because of no healing during the follow-up period, this eye underwent PK under antifungal therapy. Eyes with interface haze and Descemet’s membrane folds were followed. Conclusion: DALK is a difficult technique with a steep learning curve. In addition to the complications seen in PK, specific complications can occur in lamellar surgery. (Turk J Ophthalmol 2014; 44: 337-40

  13. Percutaneous laser-assisted recanalization of long chronic iliac artery occlusions: primary and mid-term results

    Energy Technology Data Exchange (ETDEWEB)

    Balzer, Joern O.; Gastinger, Verena; Thalhammer, Axel; Vogl, Thomas J. [Johann Wolfgang Goethe University, Department of Diagnostic and Interventional Radiology, University Clinic, Frankfurt/Main (Germany); Ritter, Ralf G.; Schmitz-Rixen, Thomas [Johann Wolfgang Goethe University, Department of Vascular and Endovascular Surgery, University Clinic, Frankfurt/Main (Germany); Lindhoff-Last, Edelgard [Johann Wolfgang Goethe University, Center of Internal Medicine I, Division of Angiology, University Clinic, Frankfurt/Main (Germany)

    2006-02-01

    We report the primary and mid-term outcome of patients with long chronic iliac artery occlusions after percutaneous excimer-laser-assisted interventional recanalization. Between 2000 and 2001, 43 patients with 46 chronic occlusions of either the common iliac artery (n=27), the external iliac artery (n=13) or both (n=3) underwent laser-assisted percutaneous transluminal angioplasty and implantation of stents. The average length of the occlusion was 57.1{+-}26 mm. After laser-assisted angioplasty and implantation of a total of 60 stents, the patients were followed up for up to 4 years. Patency rates were analyzed by ankle-brachial index (ABI) measurement and duplex ultrasound. The primary technical success rate was 95.3%, with a major complication rate of 6.9%. Clinical improvement as categorized by the Rutherford guidelines could be observed in 97.6% of cases. The ABI of all patients improved from an average of 0.46{+-}0.08 before intervention to 0.97{+-}0.13 at the end of the follow-up period. The overall primary patency rate was 86.1%. Four reinterventions were successful (secondary patency rate 95.4%). The mid-term results of the percutaneous recanalization of iliac artery occlusions with primary and secondary patency rates of 86.1 and 95.4% are similar to those of the treatment of short stenoses. (orig.)

  14. New technology update: femtosecond laser in cataract surgery

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    Nagy ZZ

    2014-06-01

    Full Text Available Zoltan Z NagyDepartment of Ophthalmology, Semmelweis University, Budapest, HungaryAbstract: Femtosecond lasers represent a new frontier in cataract surgery. Since their ­introduction and first human treatment in 2008, a lot of new developments have been achieved. In this review article, the physical principle of femtolasers is discussed, together with the indications and side effects of the method in cataract surgery. The most important clinical results are also presented regarding capsulotomy, fragmentation of the crystalline lens, corneal wound creation, and refractive results. Safety issues such as endothelial and macular changes are also discussed. The most important advantage of femtolaser cataract technology at present is that all the important surgical steps of cataract surgery can be planned and customized, delivering unparalleled accuracy, repeatability, and consistency in surgical results. The advantages of premium lenses can be maximally used in visual and presbyopia restoration as well. The advantages of ­premium lenses can be maximally used, not only in visual, but in presbyopia restoration as well. Quality of vision can be improved with less posterior chamber lens (PCL tilt, more centralized position of the PCL, possibly less endothelial damage, less macular edema, and less posterior capsule opacification (PCO formation. This technological achievement should be followed by other technical developments in the lens industry. Hopefully this review article will help us to understand the technology and the results to ­demonstrate the differences between the use of femtolasers and phacoemulsification-based cataract surgery. The most important data of the literature are summarized to show ophthalmologists the benefits of the technology in order to provide the best refractive results to the patient.Keywords: femtosecond laser-assisted cataract surgery, capsulotomy, lens fragmentation, corneal wound, arcuate keratotomy, safety

  15. Comparison of Outcomes in Patients Who Underwent Deep Anterior Lamellar Keratoplasty and Those Converted to Penetrating Keratoplasty

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    Yusuf Koçluk

    2017-03-01

    Full Text Available Objectives: To compare clinical outcomes of cases who underwent deep anterior lamellar keratoplasty (DALK and cases who were converted to penetrating keratoplasty (PKP from DALK surgery. Materials and Methods: The records of 54 patients for whom DALK surgery was planned and were operated for different diagnoses between March 2013 and June 2015 were retrospectively analyzed. Patients were divided into two groups: group 1 (PKP group consisted of 23 cases who were converted to PKP due to Descemet’s membrane perforation at any stage of surgery; group 2 (DALK group consisted of 31 patients whose surgery could be completed as DALK. Preoperative and postoperative follow-up results were evaluated in each group. Results: Corrected distance visual acuity (CDVA increased in the postoperative period according to baseline in both groups. However, there was no statistically significant difference in the rates of CDVA increase between the groups (p=0.142. The mean astigmatism measured by corneal topography at final examination was 5.8±2.3 diopters in group 1 and 5.4±1.8 diopters in group 2. The difference between groups was not statistically significant (p=0.430. The groups were not statistically different regarding postoperative pachymetry (p=0.453. The grafts in all 54 patients (100% were clear at final postoperative examination. There were no statistically significant differences between the groups in terms of postoperative complications. Conclusion: Similar clinical outcomes were obtained in our study for patients who underwent DALK and those whose procedure was converted from DALK to PKP.

  16. Comparison of Outcomes in Patients Who Underwent Deep Anterior Lamellar Keratoplasty and Those Converted to Penetrating Keratoplasty

    Science.gov (United States)

    Koçluk, Yusuf; Alyamaç Sukgen, Emine; Burcu, Ayşe

    2017-01-01

    Objectives: To compare clinical outcomes of cases who underwent deep anterior lamellar keratoplasty (DALK) and cases who were converted to penetrating keratoplasty (PKP) from DALK surgery. Materials and Methods: The records of 54 patients for whom DALK surgery was planned and were operated for different diagnoses between March 2013 and June 2015 were retrospectively analyzed. Patients were divided into two groups: group 1 (PKP group) consisted of 23 cases who were converted to PKP due to Descemet’s membrane perforation at any stage of surgery; group 2 (DALK group) consisted of 31 patients whose surgery could be completed as DALK. Preoperative and postoperative follow-up results were evaluated in each group. Results: Corrected distance visual acuity (CDVA) increased in the postoperative period according to baseline in both groups. However, there was no statistically significant difference in the rates of CDVA increase between the groups (p=0.142). The mean astigmatism measured by corneal topography at final examination was 5.8±2.3 diopters in group 1 and 5.4±1.8 diopters in group 2. The difference between groups was not statistically significant (p=0.430). The groups were not statistically different regarding postoperative pachymetry (p=0.453). The grafts in all 54 patients (100%) were clear at final postoperative examination. There were no statistically significant differences between the groups in terms of postoperative complications. Conclusion: Similar clinical outcomes were obtained in our study for patients who underwent DALK and those whose procedure was converted from DALK to PKP.

  17. Laser-Assisted Stir Welding of 25-mm-Thick HSLA-65 Plate

    Science.gov (United States)

    Williamson, Keith M.

    2002-12-01

    Laser-assisted stir welding is a hybrid process that combines energy from a laser with functional heating and mechanical energy to join materials in the solid state. The technology is an adaptation of friction stir welding which is particularly suited for joining thick plates. Aluminum plates up to 75 mm thick have been successfully joined using friction stir welding. Since joining occurs in the solid state, stir technology offers the capability for fabricating full penetration joints in thick plates with better mechanical properties and less weld distortion than is possible by fusion processes. Currently friction stir welding is being used in several industries to improve productivity, reduce weight, and increase the strength of welded structures. Examples include: (a) the aircraft/aerospace industry where stir technology is currently being used to fabricate the space shuttle's external tank as well as components of the Delta family of rockets; (b) the shipping industry where container manufacturers are using stir technology to produce lighter containers with more payload capacity; and (c) the oil industry where offshore platform manufactures are using automated stir welding plants to fabricate large panels and structures up to 16 meters long with widths as required. In all these cases, stir technology has been restricted to aluminum alloys; however, stainless and HSLA 65 steels have been recently stir welded with friction as the primary heat source. One of the difficulties in adapting stir welding to steel is tool wear aggravated by the high tool rubbing velocities needed to provide frictional heat input into the material. Early work showed that the tool shoulder reached temperatures above 1000 C and the weld seam behind the tool stayed within this temperature range for up to 25 mm behind the tool. Cross sections of stir welded samples showed that the heat-affected zone is relatively wide and follows the profile of the tool shoulder. Besides minimizing the tool

  18. Laser-assisted lipolysis for cankle remodelling: a prospective study in 30 patients.

    Science.gov (United States)

    Leclère, Franck Marie; Moreno-Moraga, Javier; Mordon, Serge; Servell, Pascal; Unglaub, Frank; Kolb, Frédéric; Rimareix, Françoise; Trelles, Mario A

    2014-01-01

    Cankles refer to the area where the calf and ankle meet. Unaesthetic fat cankles, where definition between the calf and ankle is impossible, are a frustrating aesthetic deformity, which are exacerbated by their genetic conditioning and special resistance to diet. This article reports our experience with laser-assisted lipolysis (LAL) in cankle remodelling. A total of 30 patients were treated for unaesthetic fat cankles with LAL. The 924/975-nm diode laser used in this study consisted of two lasers, one emitting at 924 nm, and the other at 975 nm. According to our mathematical models, we assumed that to destroy 1 ml of fat, 0.1 kJ was required in dual emission mode at 924/975 nm. Patients were asked to file a satisfaction questionnaire. Ultrasound was used to measure the fat thickness pre- and postoperatively. Oedema in both lateral sulcus of the Achilles tendon was seen in all patients. It subsided after 4 weeks in nine cases and 6 weeks in 21 cases. Only two patients developed mild hyperpigmentation that disappeared, respectively, after 4 and 10 weeks. Pain during the anaesthesia and discomfort after the procedure were low with this technique. Mean down time was 1.0 day. Of the 30 patients, 29 would recommend this treatment. Overall, high patient and investigator satisfaction was confirmed by the sonography used to measure decrease in fat thickness. LAL in cankle remodelling is a safe and reproducible technique that is particularly appreciated by the patient. The procedure allows homogenous reduction of fatty tissue together with skin tightening.

  19. Laser-assisted structuring and modification of LiCoO2 thin films

    Science.gov (United States)

    Kohler, R.; Proell, J.; Ulrich, S.; Trouillet, V.; Indris, S.; Przybylski, M.; Pfleging, W.

    2009-02-01

    The material development of improved lithium ion batteries will play an important role in future mobile applications and energy storage systems. Electrode materials made of nano-composited materials are expected to improve battery lifetime and will lead to an enhancement of lithium diffusion and thus improve battery capacity and cyclability. In this study, research was conducted to further improve the electrochemical properties of thin film cathodes by increasing the surface to volume ratio and thereby the lithium intercalation rate. Cathode materials were synthesised by r.f. magnetron sputtering of LiCoO2 targets in a pure argon plasma. LiCoO2 films 3 μm thick and with a grain size of 10 to 500 nm were deposited on silicon and stainless steel substrates. The deposition parameters (argon pressure, substrate bias) were varied to create stoichiometric films with controlled nano-crystalline texture and morphology. During laser-assisted surface treatment, cone-shaped periodic surface structures were produced. For this purpose high repetition excimer laser radiation at wavelengths of 193 nm and 248 nm and with short laser pulse widths (4-6 ns) were used. Structure sizes varied with laser and processing parameters, e.g. laser fluences, pulse number, wavelength and processing gas. Laser annealing in air or furnace annealing in a controlled argon/oxygen environment were then used to create the high temperature phase of LiCoO2 (HT-LiCoO2). The sputtered films were studied with Raman spectroscopy, x-ray photoelectron spectroscopy and x-ray diffraction to determine their stoichiometry and crystallinity before and after laser treatment. The development of HT-LiCoO2 and also the formation of a Co3O4 phase were discussed. By means of electrochemical cycling, the performance of the manufactured films was investigated.

  20. Laser-assisted removal of a feline eosinophilic granuloma from the back of the tongue.

    Science.gov (United States)

    Kovács, Katalin; Jakab, Csaba; Szász, Attila Marcell

    2009-09-01

    Recently, an increase in the occurrence of oral diseases in cats has been observed. Symptoms vary from case to case, but loss of appetite or fastidiousness can almost always be noted. Proliferative inflammatory eosinophilic granulomatosis is a common disease in cats, which may be localised to the skin, the mucocutaneous junctions or the oral cavity. The disease has three different manifestations: indolent cellular ulcer, eosinophilic plaque, and eosinophilic granuloma. The last mentioned form predominantly affects the medial surface of the thigh, the cheek, the tongue and the palate. Pain is not common, the lesion is nonpruritic if localised to the skin, but the nodular form in the oral cavity may make deglutition difficult. In this case, a 10.5-year-old cat was presented in poor condition due to feeding problems. Examination revealed a mass of unknown origin with macroscopically tumorous appearance, localised to the pharyngeal part of the tongue, which made swallowing and voluntary feeding difficult. The granuloma was removed by laser-assisted surgery. After adequate preparation, a LASER diode with 6-10 W output power was used, set to continuous constant-amplitude output (CW) running in a 0.6 mm optic fibre to the site of interest. The removed tissue was examined for pathomorphological features: haematoxylin and eosin, Giemsa, Azan and PAS stainings were performed to aid diagnosis. After surgery the cat recovered fast on steroids, and its condition and quality of life improved greatly. The traditional surgical technique was inapplicable due to the heavy vasculature and corresponding bleeding of the tongue.

  1. Laser-assisted atom probe tomography of Ti/TiN films deposited on Si.

    Science.gov (United States)

    Sanford, N A; Blanchard, P T; White, R; Vissers, M R; Diercks, D R; Davydov, A V; Pappas, D P

    2017-03-01

    Laser-assisted atom probe tomography (L-APT) was used to examine superconducting TiN/Ti/TiN trilayer films with nominal respective thicknesses of 5/5/5 (nm). Such materials are of interest for applications that require large arrays of microwave kinetic inductance detectors. The trilayers were deposited on Si substrates by reactive sputtering. Electron energy loss microscopy performed in a scanning transmission electron microscope (STEM/EELS) was used to corroborate the L-APT results and establish the overall thicknesses of the trilayers. Three separate batches were studied where the first (bottom) TiN layer was deposited at 500°C (for all batches) and the subsequent TiN/Ti bilayer was deposited at ambient temperature, 250°C, and 500°C, respectively. L-APT rendered an approximately planar TiN/Si interface by making use of plausible mass-spectral assignments to N3(1+), SiN(1+), and SiO(1+). This was necessary since ambiguities associated with the likely simultaneous occurrence of Si(1+) and N2(1+) prevented their use in rendering the TiN/Si interface upon reconstruction. The non-superconducting Ti2N phase was also revealed by L-APT. Neither L-APT nor STEM/EELS rendered sharp Ti/TiN interfaces and the contrast between these layers diminished with increased film deposition temperature. L-APT also revealed that hydrogen was present in varying degrees in all samples including control samples that were composed of single layers of Ti or TiN.

  2. The impact of laser-assisted hatching on the outcome of frozen human embryo transfer cycles.

    Science.gov (United States)

    Kanyo, Katalin; Zeke, Jozsef; Kriston, Rita; Szücs, Zoltan; Cseh, Sandor; Somoskoi, Bence; Konc, Janos

    2016-10-01

    Biochemical modifications of zona pellucida (ZP) result in zona hardening. Zona hardening (ZH) is induced by several factors such as advancing maternal age, in vitro culture conditions and cryopreservation and adversely effects implantation. The objective of the clinical study was to determine whether or not laser-assisted hatching (LAH) applied on day 3 frozen embryos improves the outcome of frozen embryo transfer (FET) cycles in patients with recurrent implantation failure and/or advanced female age. In total, 413 patients of different ages with recurrent implantation failure (maximum three cycles) were involved into the study. Patients were allocated randomly into LAH and control groups. On the day of FET, after thawing and just before FET, the ZP was thinned using a laser system. In the control group no treatment was applied on frozen embryo before transfer. The main outcome measures were clinical pregnancy rate. Overall, the results indicate a tendency that LAH increased (P = 0.08) clinical pregnancy. However, for patients older than 37 years, LAH increased pregnancy rates significantly (P = 0.03). In the LAH and control groups, the age of patients and the number of transferred embryos influenced pregnancy rates (P = 0.01). For patients older than 37 years, no effect of number of transferred embryos was detected (P = 0.14). The incidence of multiple pregnancies also increased in the LAH group (P = 0.01). In conclusion, in older woman, to overcome the negative effect of zona hardening, LAH could be performed on frozen embryos as a routine strategy before FET in frozen cycles in order to increase the possibility of pregnancy formation.

  3. Human clinical and histologic evaluation of laser-assisted new attachment procedure.

    Science.gov (United States)

    Nevins, Marc L; Camelo, Marcelo; Schupbach, Peter; Kim, Soo-Woo; Kim, David M; Nevins, Myron

    2012-10-01

    This investigation was designed to evaluate the healing response to the laser-assisted new attachment procedure (LANAP). Eight patients presenting with 12 teeth predetermined to be surgically extracted were enrolled and consented to treatment with full-mouth LANAP therapy. LANAP surgical therapy consisted of a first pass with a 360-Μm fiber diameter, laser settings with verified output of 4.0 W and energy density of 1,965 mJ/mm2, 100-Μs pulse duration, and 20 Hz applied from the gingival margin to the base of the pocket parallel to the root surface and moved laterally and apically to remove the diseased pocket epithelium. The teeth were aggressively scaled and root planed with piezo ultrasonic instrumentation. A second pass was performed with a 360-Μm fiber diameter, laser settings with verified output of 4.0 W and energy density of 1,965 mJ/mm2, 650-Μs pulse duration, and 20 Hz applied from the apical extent of the bone defect to the gingival margin. After 9 months of healing, en bloc biopsy extractions were provided. Ten teeth were analyzed histologically to assess the periodontal wound healing. Five teeth evidenced a degree of periodontal regeneration with new cementum, periodontal ligament, and alveolar bone. One tooth had new attachment with new cementum and inserting collagen fibers, and four teeth healed via a long junctional epithelium. LANAP therapy should be further investigated with long-term clinical trials to compare the stability of clinical results to conventional therapy. This report provides evidence that LANAP therapy can induce periodontal regeneration.

  4. Endoluminal laser-assisted vascular anastomosis-an in vivo study in a pig model.

    Science.gov (United States)

    Mbaidjol, Zacharia; Kiermeir, David; Schönfeld, Annemarie; Arnoldi, Jörg; Frenz, Martin; Constantinescu, Mihai A

    2017-08-01

    Microvascular surgery is time consuming and requires high expertise. Laser-assisted vascular anastomosis (LAVA) is a promising sutureless technique that has the potential to facilitate this procedure. In this study, we evaluate the handling of our soldering material and the 1-week patency rate in a porcine model. Six pigs were subjected to LAVA. For each pig, the saphenous artery on one side was transected while the contralateral side was used as control. A porous polycaprolactone scaffold soaked in 40% (w/w) bovine serum albumin solution in combination with 0.1% (w/w) indocyanine green was wrapped at the anastomosis site and at the control site. Both sides were then soldered with a diode laser coupled into a light diffuser fiber emitting radiation with a wavelength of 808 nm and a power of 2-2.2 W. Vessels were successfully soldered with a 100% immediate patency rate. The 1-week patency rate was 83% for the anastomoses versus 67% for the control side. Vessels irradiated for 80 to 90 s tended to maintain the highest patency rate. Macroscopically, there was no difference between the two sides. The patch was easy to handle provided that the environment could be kept dry. This study shows the potential and the limitations of endoluminal LAVA as a one-step procedure without the use of stay sutures. Further studies are needed to improve the soldering material, the long-term patency rate, and standardized irradiation parameters. The long-term effects of laser soldering on the vessel wall remain to be determined.

  5. Parametric modeling and optimization of laser scanning parameters during laser assisted machining of Inconel 718

    Science.gov (United States)

    Venkatesan, K.; Ramanujam, R.; Kuppan, P.

    2016-04-01

    This paper presents a parametric effect, microstructure, micro-hardness and optimization of laser scanning parameters (LSP) on heating experiments during laser assisted machining of Inconel 718 alloy. The laser source used for experiments is a continuous wave Nd:YAG laser with maximum power of 2 kW. The experimental parameters in the present study are cutting speed in the range of 50-100 m/min, feed rate of 0.05-0.1 mm/rev, laser power of 1.25-1.75 kW and approach angle of 60-90°of laser beam axis to tool. The plan of experiments are based on central composite rotatable design L31 (43) orthogonal array. The surface temperature is measured via on-line measurement using infrared pyrometer. Parametric significance on surface temperature is analysed using response surface methodology (RSM), analysis of variance (ANOVA) and 3D surface graphs. The structural change of the material surface is observed using optical microscope and quantitative measurement of heat affected depth that are analysed by Vicker's hardness test. The results indicate that the laser power and approach angle are the most significant parameters to affect the surface temperature. The optimum ranges of laser power and approach angle was identified as 1.25-1.5 kW and 60-65° using overlaid contour plot. The developed second order regression model is found to be in good agreement with experimental values with R2 values of 0.96 and 0.94 respectively for surface temperature and heat affected depth.

  6. High-speed deposition of titanium carbide coatings by laser-assisted metal–organic CVD

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yansheng [Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Tu, Rong, E-mail: turong@whut.edu.cn [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Goto, Takashi [Institute for Materials Research, Tohoku University, Aoba-ku, 2-1-1 Katahira, Sendai 980-8577 (Japan)

    2013-08-01

    Graphical abstract: - Highlights: • A semiconductor laser was first used to prepare wide-area LCVD-TiC{sub x} coatings. • The effect of laser power for the deposition of TiC{sub x} coatings was discussed. • TiC{sub x} coatings showed a columnar cross section and a dense surface texture. • TiC{sub x} coatings had a 1–4 order lower laser density than those of previous reports. • This study gives the possibility of LCVD applying on the preparation of TiC{sub x} coating. - Abstract: A semiconductor laser-assisted chemical vapor deposition (LCVD) of titanium carbide (TiC{sub x}) coatings on Al{sub 2}O{sub 3} substrate using tetrakis (diethylamido) titanium (TDEAT) and C{sub 2}H{sub 2} as source materials were investigated. The influences of laser power (P{sub L}) and pre-heating temperature (T{sub pre}) on the microstructure and deposition rate of TiC{sub x} coatings were examined. Single phase of TiC{sub x} coatings were obtained at P{sub L} = 100–200 W. TiC{sub x} coatings had a cauliflower-like surface and columnar cross section. TiC{sub x} coatings in the present study had the highest R{sub dep} (54 μm/h) at a relative low T{sub dep} than those of conventional CVD-TiC{sub x} coatings. The highest volume deposition rate (V{sub dep}) of TiC{sub x} coatings was about 4.7 × 10{sup −12} m{sup 3} s{sup −1}, which had 3–10{sup 5} times larger deposition area and 1–4 order lower laser density than those of previous LCVD using CO{sub 2}, Nd:YAG and argon ion laser.

  7. Fractional carbon-dioxide (CO2) laser-assisted topical therapy for the treatment of onychomycosis.

    Science.gov (United States)

    Bhatta, Anil Kumar; Keyal, Uma; Huang, Xin; Zhao, Jing Jun

    2016-05-01

    Inability of topical medications to penetrate via nail plate brings a great challenge to clinicians in treating onychomycosis. Furthermore, oral medications are not appropriate for all patients because of drug interactions, adverse effects, and contraindications. We sought to evaluate the clinical efficacy of fractional carbon-dioxide laser-assisted topical therapy for onychomycosis. In total, 75 patients with 356 onychomycotic nails confirmed by mycologic examination were included in this study. All the affected nails received 3 sessions of laser therapy at 4-week intervals and once-daily application of terbinafine cream for 3 months. In all, 94.66% and 92% of the treated patients were potassium hydroxide and culture negative, respectively, after 3 months of treatment. However, only 84% and 80% were potassium hydroxide and culture negative, respectively, at 6 months of follow-up. Using Scoring Clinical Index for Onychomycosis electronic calculator, 73.33% of the patients scored higher than 6 and 26.66% of the patients scored 6 or less. Those who scored more than 6 were evaluated clinically and 98.18% of them showed response to treatment at 3 months and 78.18% of them at 6 months of follow-up. Lack of control group and short duration of follow-up are limitations. Fractional carbon-dioxide laser therapy combined with topical antifungal was found to be effective in the treatment of onychomycosis. However, randomized clinical studies are needed before it can be widely used in clinics. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  8. Holmium laser assisted ′anatomical′ enucleation of adenoma of benign hyperplasia of prostate

    Directory of Open Access Journals (Sweden)

    Shivadeo S Bapat

    2006-01-01

    Full Text Available Aims: To present our technique of Holmium Laser assisted "ANATOMICAL" enucleation of the benign prostatic adenoma (HoLEP in 219 patients. Procedure is based on the principle of digital enucleation of the adenoma from its surgical capsule, but performed entirely by perurethral endoscopic technique assisted by Holmium Laser. Materials and Methods: From March 2001 to November 2004, 219 patients under went HoLEP. After the initial cuts from bladder neck to verumontanum at 5 and 7 o′clock position, capsule is identified. The beak of the resectoscope sheath was inserted in the plane between the capsule and the adenoma and the adenoma was physically pushed away towards the urethra from the capsule. Laser was used to coagulate the bleeders, to cut the mucosal attachments and tough stromal tissue. Procedure was repeated for median and two lateral lobes. There was minimal bleeding and fluid absorption. Complications were few. Results: In 206 cases successful enucleation of the adenoma was carried out. First 13 cases formed part of the learning curve and were completed by standard transurethral resection of prostate (TURP. IPSS score dropped from average of 23 to 8 and peak flow improved from 20. No patient had postoperative urinary incontinence or stricture. Conclusions: HoLEP is an effective alternative to TURP. Ultimate end results replicate the end results of open enucleation of BPH without its morbidity and have all the advantages of endoscopic surgery. It offers distinct advantages over standard TURP as the incidence of blood transfusion and fluid absorption are greatly minimized.

  9. Laser-assisted ultrafast photoassociation in HeH{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Bo Y.; Shin, Seokmin [School of Chemistry (BK21), Seoul National University, Seoul 151-747 (Korea, Republic of); Santamaria, Jesus [Departamento de Química Física I, Universidad Complutense, 28040 Madrid (Spain); Sola, Ignacio R., E-mail: isola@ucm.es [Departamento de Química Física I, Universidad Complutense, 28040 Madrid (Spain)

    2014-10-17

    Highlights: • We study numerically photoassociation assisted by femtosecond pulses in HeH{sup 2+}. • The bond can be formed in a hot collision with the electron initially in H or He{sup +}. • We predict Rabi oscillations of the yield as a function of the pulse amplitude. • We predict weak dependence of the yield on the initial nuclear momentum uncertainty. - Abstract: In this work we report control on the photoassociation of a proton and a Helium cation, or an alpha particle and an Hydrogen atom, to form HeH{sup 2+} assisted by strong femtosecond laser pulses. The results follow from the numerical solution of the time-dependent Schrödinger equation using soft-core Coulomb potentials in a (1+1)D model (one dimension for the electronic motion plus one dimension for the nuclear motion) and for a nuclear Hamiltonian describing the dynamics in four electronic states. We study the dependence of the photoassociation yield on the initial nuclear wave function for a hot collision (impact kinetic energy of the order of a eV) and on the laser parameters. We predict high sensitivity on the synchronization of the laser with the collision time and Rabi oscillations for the yield as a function of the pulse amplitude and duration, while the ionization and inelastic scattering can be minimized with pulses of 50 fs or shorter.

  10. Evaluation of corneal biomechanical properties following penetrating keratoplasty using ocular response analyzer

    Directory of Open Access Journals (Sweden)

    Vanathi Murugesan

    2014-01-01

    Full Text Available Purpose: To evaluate corneal biomechanical properties in eyes that has undergone penetrating keratoplasty (PK. Materials and Methods: Retrospective observational study in a tertiary care centre. Data recorded included ocular response analyzer (ORA values of normal and post-keratoplasty eyes [corneal hysteresis (CH, corneal resistance factor (CRF, Goldmann-correlated intraocular pressure (IOPg, and cornea-compensated intraocular pressure (IOPcc], corneal topography, and central corneal thickness (CCT. Wilcoxon signed rank test was used to analyze the difference in ORA parameter between post-PK eyes and normal eyes. Correlation between parameters was evaluated with Spearman′s rho correlation. Results: The ORA study of 100 eyes of 50 normal subjects and 54 post-keratoplasty eyes of 51 patients showed CH of 8.340 ± 1.85 and 9.923 ± 1.558, CRF of 8.846 ± 2.39 and 9.577 ± 1.631 in post-PK eyes and normal eyes, respectively. CH and CRF did not correlate with post-keratoplasty astigmatism (P = 0.311 and 0.276, respectively while a significant correlation was observed with IOPg (P = 0.004 and IOPcc (P < 0.001. Conclusion: Biomechanical profiles were significantly decreased in post-keratoplasty eyes with significant correlation with higher IOP as compared with that in normal eyes.

  11. Outcomes of Penetrating Keratoplasty for Macular Corneal Dystrophy

    Directory of Open Access Journals (Sweden)

    Farid Karimian

    2009-01-01

    Full Text Available

    PURPOSE: To report the outcomes of penetrating keratoplasty (PKP in patients with macular corneal dystrophy (MCD. METHODS: This retrospective case series includes consecutive patients with MCD who underwent PKP from 1986 to 2006 with at least 6 months' follow-up. Main outcome measures included best spectacle-corrected visual acuity (BSCVA, postoperative astigmatism and graft survival. RESULTS: Sixty-two eyes of 39 patients with mean age of 34.0±10.5 (range 13-58 years at the time of keratoplasty were included for analysis. After a mean follow-up period of 52.0±47.3 (range 6-190 months, BSCVA improved from 1.4±0.4 logMAR (4/100 preoperatively to 0.2±0.3 logMAR (20/32 at final follow-up (P < 0.001. Mean postoperative BSCVA was 0.15±0.40 logMAR in patients (36 eyes aged less than 35 years at the time of surgery as compared to 0.26±0.25 logMAR in subjects (26 eyes older than 35 years (P=0.005. Final astigmatism was comparable with different suturing techniques including separate, continuous, and combined sutures (P=0.9. All grafts were clear at final follow-up except a single case of MCD with visually insignificant recurrence. Episodes of immunologic graft rejection occurred in 12 eyes (19.4% but none led to graft failure. CONCLUSION: PKP for MCD entails favorable outcomes in terms of graft survival and visual improvement

  12. Clinical study of two kinds of bandage contact lenses after laser-assisted subepithelial keratectomy

    Directory of Open Access Journals (Sweden)

    Wan-Ting Zhang

    2016-07-01

    Full Text Available AIM: To investigate the clinical safety and effectiveness of the two kind of bandage contact lenses: Senofilcon A(Johnson & Johnson Acuvue Oasysand Balafilcon A(Bausch& Lomb pure visionafter laser-assisted subepithelial keratectomy(LASEK. METHODS: Thirty-eight patients(76 eyeswho had undergone the LASEK were divided into two groups. One group of patients wore Balafilcon A, the other group of patients fitted with Senofilcon A. The lenses were worn continuously for 7d. This was a seven-day experience and the patients scored for the symptom of the eyes(sore eyes, foreign body sensation and tearingon the third day and the seventh day. Both of the two groups of patients taken off the soft contact lens on the seventh day and let their vision and corneal staining checked.RESULTS: The symptoms of eye sore and tearing of the two groups patients were different. The patients who wore the Senofilcon A were better. The pain of eyes were also different at 3 and 7d after surgeries(Z=-4.146, P=0.000; Z=-2.814, P=0.005. The difference on tearing between the two groups at 3 and 7d after surgeries were significant(Z=-2.309, P=0.021; Z=-3.276, P=0.001. There was no difference on sensation of dryness between the two groups at 3 and 7d after surgeries(Z=-0.447, P=0.655; Z=-0.966, P=0.334. After the lenses were taken off, the visual acuity of patients wearing Senofilcon A was better(t=3.800, P=0.001; corneal staining showed limited spots in 1-2 quadrants with significant difference(Z=-2.384,P=0.017. CONCLUSION: The Senofilcon A(Johnson & Johnson Acuvue Oasysand Balafilcon A(Bausch& Lomb pure visionbandage contact lenses are safe and effective after LASEK, and the former is better than the latter in epithelial regeneration.

  13. Deep anterior lamellar keratoplasty for the management of iatrogenic keratectasia occurring after hexagonal keratotomy

    Directory of Open Access Journals (Sweden)

    Paras Mehta

    2012-01-01

    Full Text Available Iatrogenic keratectasia has been reported subsequent to refractive surgery or trauma. Hexagonal keratotomy (HK is a surgical incisional technique to correct hyperopia. A number of complications have been reported following this procedure, including irregular astigmatism, wound healing abnormalities and corneal ectasia. When visual acuity is poor because of ectasia or irregular astigmatism and contact lens fitting is not possible, penetrating or lamellar keratoplasty can be performed. Since incisions in refractive keratotomy are set at 90-95% depth of cornea, intraoperative microperforations are known to occur and lamellar keratoplasty may become difficult. We describe deep anterior lamellar keratoplasty (DALK used to successfully manage keratectasia after HK. Pre DALK vision was 20/400 and post DALK vision was 20/30 two months after surgery. This report aims to show improved visual outcome in corneal ectasia secondary to HK. DALK can be a procedure of choice with proper case selection.

  14. Fungal interface keratitis by Candida orthopsilosis following deep anterior lamellar keratoplasty.

    Science.gov (United States)

    Wessel, Julia M; Bachmann, Björn O; Meiller, Ralph; Kruse, Friedrich E

    2013-01-23

    A 39-year-old male patient underwent uncomplicated deep anterior lamellar keratoplasty due to keratoconus. On day 5 after surgery, small whitish infiltrates developed in the corneal interface. The diagnosis of fungal keratitis was made when the culture medium of the graft grew Candida after the surgical intervention. Despite intensive antimycotic treatment and irrigation of the interface, the infiltrates persisted and eventually enlarged. Therefore, revision surgery with penetrating keratoplasty was performed. Microbiological analysis showed Candida orthopsilosis in the culture of the excised graft button. Histopathological staining of the excised graft showed periodic acid-Schiff-positive and Grocott methenamine silver-positive clusters of yeast between Descemet's membrane and the deep corneal stroma with focal perforations through Descemet's membrane. The treatment of mycotic keratitis caused by C orthopsilosis is challenging. Antimycotic treatment was unsuccessful in this case. Progression of the keratitis and perforation of Descemet's membrane suggest that early surgical intervention by penetrating keratoplasty is required.

  15. Comparison of visual and topographic outcomes of deep-anterior lamellar keratoplasty and penetrating keratoplasty in keratoconus

    Science.gov (United States)

    Yüksel, Bora; Kandemir, Baran; Uzunel, Umut Duygu; Çelik, Ozan; Ceylan, Sezgin; Küsbeci, Tuncay

    2017-01-01

    AIM To compare visual, surgical and topographic outcomes of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) for keratoconus (KC). METHODS In this multicenter, prospective, randomized clinical trial 76 eyes of 71 KC patients operated between January 2011 and July 2014 in 2 tertiary referral hospitals were included. Consecutive patients were alternately selected to receive one of the two surgical methods. Thirty eight eyes underwent DALK with the big-bubble technique and 38 eyes underwent PK. RESULTS Mean best spectacle corrected visual acuity (BSCVA) at the first postoperative week (P=0.012) and the first postoperative month (P<0.001) was statistically significantly higher in DALK group. The mean BSCVA at 12mo was not significantly different for DALK (0.30±1.99 logMAR) versus PK (0.40±0.33 logMAR) (P=0.104). The 76.3% of the eyes had a BSCVA over 0.5 in DALK and 47.4% in PK group (P=0.009). The 7.9% of the eyes had a BSCVA of 1.0 in DALK and 5.3% in PK group (P=0.644). Mean spherical equivalent was -2.94 D in DALK and -3.09 D in PK group. Mean topographic astigmatism was 4.62 D and 4.18 D respectively. Regular topographic patterns were observed in 31 (81.6%) of DALK and 29 (76.3%) of PK (P=0.574). The most frequent topographic pattern was oblate asymmetric bow tie, seen in 39.5% in DALK and 23.7% in PK. CONCLUSION Big bubble DALK provides an earlier visual improvement compare to PK. However, visual and topographic outcomes are similar to those in PK at 1y. Postoperative complications including rejection and intraocular pressure elevation are more frequent in PK. DALK is a safer alternative to PK for KC. However, intraoperative perforation of the Descemet's membrane is a significant complication.

  16. Polarization Effects in Two-Photon Free-Free Transitions in Laser-Assisted Electron-Hydrogen Collisions

    CERN Document Server

    Cionga, Aurelia

    2013-01-01

    Two-photon free-free transitions in elastic laser-assisted electron-hydrogen collisions are studied in the domain of high scattering energies and low or moderate field intensities, in the third order of perturbation theory, taking into account all the involved Feynman diagrams. Based on the analytical expressions of the transition amplitudes, the differential cross sections for two-photon absorption/emission are computed at impact energy $E_i=100$ eV. The effect of field polarizations on the angular distribution and on the frequency dependence of the differential cross section is analyzed.

  17. Analysis of Macular and Retinal Nerve Fiber Layer Thickness in Children with Refractory Amblyopia after Femtosecond Laser-assisted Laser In situ Keratomileusis: A Retrospective Study

    Directory of Open Access Journals (Sweden)

    Peng-Fei Zhao

    2017-01-01

    Conclusions: The foveal center retinal edema after FS-LASIK is mild and reversible in children, that mostly occurred in the high myopic group with no effect on the visual acuity, and is always relieved within 1 week.

  18. Clinical features of single and repeated globe rupture after penetrating keratoplasty.

    Science.gov (United States)

    Murata, Noriaki; Yokogawa, Hideaki; Kobayashi, Akira; Yamazaki, Natsuko; Sugiyama, Kazuhisa

    2013-01-01

    In this paper, we report our experience of the clinical features of single and repeated globe rupture after penetrating keratoplasty. We undertook a retrospective analysis of single and repeated globe ruptures following keratoplasty in eight eyes from seven consecutive patients referred to Kanazawa University Hospital over a 10-year period from January 2002 to March 2012. We analyzed their ophthalmic and demographic data, including age at time of globe rupture, incidence, time interval between keratoplasty and globe rupture, cause of rupture, complicated ocular damage, and visual outcome after surgical repair. Five patients (71.4%) experienced a single globe rupture and two patients (28.6%) experienced repeated globe ruptures. Patient age at the time of globe rupture was 75.4 ± 6.8 (range 67-83) years. Four of the patients were men and three were women. During the 10-year study period, the incidence of globe rupture following penetrating keratoplasty was 2.8%. The time interval between penetrating keratoplasty and globe rupture was 101 ± 92 months (range 7 months to 23 years). The most common cause of globe rupture in older patients was a fall (n = 5, 79.8 ± 3.7 years, all older than 67 years). Final best-corrected visual acuity was >20/200 in three eyes (37.5%). In all except one eye, globe rupture involved the graft-host junction; in the remaining eye, the rupture occurred after disruption of the extracapsular cataract extraction wound by blunt trauma. Preventative measures should be taken to avoid single and repeated ocular trauma following penetrating keratoplasty.

  19. Donor disc attachment assessment with intraoperative spectral optical coherence tomography during descemet stripping automated endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Edward Wylegala

    2013-01-01

    Full Text Available Optical coherence tomography has already been proven to be useful for pre- and post-surgical anterior eye segment assessment, especially in lamellar keratoplasty procedures. There is no evidence for intraoperative usefulness of optical coherence tomography (OCT. We present a case report of the intraoperative donor disc attachment assessment with spectral-domain optical coherence tomography in case of Descemet stripping automated endothelial keratoplasty (DSAEK surgery combined with corneal incisions. The effectiveness of the performed corneal stab incisions was visualized directly by OCT scan analysis. OCT assisted DSAEK allows the assessment of the accuracy of the Descemet stripping and donor disc attachment.

  20. Clinical picture and problems of keratoplasty in Richner-Hanhart syndrome (tyrosinemia type II).

    Science.gov (United States)

    Sayar, R B; von Domarus, D; Schäfer, H J; Beckenkamp, G

    1988-01-01

    The Richner-Hanhart syndrome seen in a middle-aged woman is described. The patient had the typical clinical manifestations of tyrosinemia II with a bilateral keratopathy, palmar and plantar hyperkeratosis. The patient was subjected to a specific diet and to perforating keratoplasty. Postoperative systemic therapy with steroids had a negative influence on the clinical manifestations; dendritic lesions which developed on the corneal graft disappeared after interruption of the systemic steroid therapy. This suggests that cortisone treatment after keratoplasty should be avoided in this special metabolic disorder.

  1. The results descemet-stripping automated endothelial keratoplasty at bullous keratopathy

    Directory of Open Access Journals (Sweden)

    S. V. Trufanov

    2012-01-01

    Full Text Available Purpose: to evaluate outcomes of the descemet-stripping automated endothelial keratoplasty using eye drops Kombinil-Duo dur- ing postoperative period.Methods: 26 patients suffered from bullous keratopathy underwent descemet-stripping automated endothelial keratoplasty using our own technique. We applied eye drops Kombinil-Duo during postoperative period.Results: 25 patients had clear corneas whole period of observation. Graft rejection occurred in 1 eye. Mean BSCVA was 0.47±0.21.Conclusion: Kombinil-Duo has been allowed to avoid infectious complication and to increase efficiency of the operative interven-tion during postoperative period.

  2. Detection Techniques of Femtosecond Lasers

    Institute of Scientific and Technical Information of China (English)

    LIU Li-peng; ZHOU Ming; DAI Qi-xun; CAI Lan

    2004-01-01

    The measurement techniques of femtosecond spectroscopy are effective method to investigate ultrafast dynamics, they are widely used in the fields of physics, chemistry and biology. In this paper, the principle, experiment setup and the approaches to deal with the experiment data were presented. Then different measurement techniques such as transient absorption spectroscopy, photon echoes, optical Kerr effect and degenerate four-wave mixing were explained with special examples. At last, the application prospect of measurement techniques of femtosecond spectroscopy was forecasted.

  3. Cataract Surgery Performed by High Frequency LDV Z8 Femtosecond Laser: Safety, Efficacy, and Its Physical Properties

    Directory of Open Access Journals (Sweden)

    Bojan Pajic

    2017-06-01

    Full Text Available Background: The aim of our study was to investigate the safety and efficacy of the LDV Z8 femtosecond laser in cataract surgery compared to the conventional procedure. Methods: This prospective study was performed at the Swiss Eye Research Foundation, Eye Clinic ORASIS, Reinach, Switzerland. The study included 130 eyes from 130 patients: 68 treated with femtosecond laser-assisted cataract surgery (FLACS using the FEMTO LDV Z8 and 62 treated with conventional phacoemulsification. Capsulotomy and lens fragmentation in the laser group were performed with the FEMTO LDV Z8 femtosecond laser system, which employs a new, low-energy, high repetition rate laser process for cataract surgery. In the conventional group, the capsulotomy was performed by a cystotome, and lens fragmentation was achieved by the stop-and-chop. Results: Ease of phacoemulsification (on a 4-point scale, the completeness of capsulotomy (on a 10-point scale, effective phacoemulsification time (seconds, uncorrected distance visual acuity (UCVA, best spectacle-corrected distance visual acuity (BSCVA, spherical equivalent (SE, and safety of the procedure were evaluated. The total follow-up time was three months. Conclusions: FLACS with the FEMTO LDV Z8 system was characterized by complete and reproducible capsulotomy and highly effective lens fragmentation. Postoperative visual outcomes were excellent, and the safety of the procedure was optimal.

  4. Ship-in-a-bottle integration by hybrid femtosecond laser technology for fabrication of true 3D biochips

    Science.gov (United States)

    Sima, Felix; Wu, Dong; Xu, Jian; Midorikawa, Katsumi; Sugioka, Koji

    2015-03-01

    We propose herein the "ship-in-a-bottle" integration of three-dimensional (3D) polymeric sinusoidal ridges inside photosensitive glass microfluidic channel by a hybrid subtractive - additive femtosecond laser processing method. It consists of Femtosecond Laser Assisted Wet Etching (FLAE) of a photosensitive Foturan glass followed by Two-Photon Polymerization (TPP) of a SU-8 negative epoxy-resin. Both subtractive and additive processes are carried out using the same set-up with the change of laser focusing objective only. A 522 nm wavelength of the second harmonic generation from an amplified femtosecond Yb-fiber laser (FCPA µJewel D-400, IMRA America, 1045 nm; pulse width 360 fs, repetition rate 200 kHz) was employed for irradiation. The new method allows lowering the size limit of 3D objects created inside channels to smaller details down to the dimensions of a cell, and improve the structure stability. Sinusoidal periodic patterns and ridges are of great use as base scaffolds for building up new structures on their top or for modulating cell migration, guidance and orientation while created interspaces can be exploited for microfluidic applications. The glass microchannel offers robustness and appropriate dynamic flow conditions for cellular studies while the integrated patterns are reducing the size of structure to the level of cells responsiveness. Taking advantage of the ability to directly fabricate 3D complex shapes, both glass channels and polymeric integrated patterns enable us to 3D spatially design biochips for specific applications.

  5. Nanosurgery of cells and chromosomes using near-infrared twelve-femtosecond laser pulses.

    Science.gov (United States)

    Uchugonova, Aisada; Lessel, Matthias; Nietzsche, Sander; Zeitz, Christian; Jacobs, Karin; Lemke, Cornelius; König, Karsten

    2012-10-01

    ABSTRACT. Laser-assisted surgery based on multiphoton absorption of near-infrared laser light has great potential for high precision surgery at various depths within the cells and tissues. Clinical applications include refractive surgery (fs-LASIK). The non-contact laser method also supports contamination-free cell nanosurgery. In this paper we describe usage of an ultrashort femtosecond laser scanning microscope for sub-100 nm surgery of human cells and metaphase chromosomes. A mode-locked 85 MHz Ti:Sapphire laser with an M-shaped ultrabroad band spectrum (maxima: 770  nm/830  nm) and an in situ pulse duration at the target ranging from 12 fs up to 3 ps was employed. The effects of laser nanoprocessing in cells and chromosomes have been quantified by atomic force microscopy. These studies demonstrate the potential of extreme ultrashort femtosecond laser pulses at low mean milliwatt powers for sub-100 nm surgery of cells and cellular organelles.

  6. Excimer laser-assisted retrieval of Günther Tulip vena cava filters: a pilot study in a canine Model.

    Science.gov (United States)

    Saito, Naritatsu; Shimamoto, Takeshi; Takeda, Takahide; Marui, Akira; Kimura, Takeshi; Ikeda, Tadashi; Sakata, Ryuzo

    2010-05-01

    Although most Günther Tulip filters (GTFs) can be safely retrieved within a few months after implantation, their recommended safe retrieval period is within a few weeks. This study aims to assess the feasibility of excimer laser-assisted retrieval of GTFs incorporated into the inferior vena cava (IVC) wall in a canine model. Six GTFs were implanted in six mongrel dogs and retrieved after four weeks. The retrieval system consisted of a 14-F excimer laser sheath, an 8-F guide catheter, and a 15-mm Goose Neck snare. All filters were tightly fixed to the IVC wall. After ablation of the adhesions by excimer laser emission, all filters were successfully retrieved. Final cavography after retrieval revealed no caval damage except for minor extravasation in three dogs. Examination of the caval specimen taken from a dog immediately after filter retrieval revealed partial absence of the intima and media. In the remaining five dogs, cavography performed 2 days after filter retrieval revealed complete hemostasis and almost indistinguishable intimal indentations. On follow-up cavography 28 days after filter retrieval, caval stenosis with 38% +/- 11% diameter narrowing was noted. The caval specimen obtained from a dog at 28 days showed neointima formation at the level where the filter struts were in contact with the caval wall. The other four dogs have survived for more than 3 months without any adverse events. Laser-assisted retrieval of a GTF incorporated into the IVC wall is feasible in dogs.

  7. Improvements in springback control by external force laser-assisted sheet bending of titanium and aluminum alloys

    Science.gov (United States)

    Gisario, A.; Barletta, M.; Venettacci, S.

    2016-12-01

    The present investigation deals with an external-force laser assisted bending process of Grade 2 CP titanium and AA 7075 T6 aluminum sheets. High bending angles, sharp fillet radii and control of springback were achieved by tuning the contact pressure of a hydraulically driven tool with the local and selective heating of the bending zone by irradiation with a high power diode laser. First, the role of laser operational parameters, namely power, scanning speed and number of passes, in metal bending was investigated, allowing to identify the most suitable processing window. Second, a custom-built equipment to measure the bending angle during the forming process, together with the metal temperature, was implemented. Real-time monitoring of the bending angle and temperature allowed to evaluate the continuous evolution of the geometry of the metal substrates during the external force laser-assisted bending process. Experimental results showed both metal sheets could be bent to high angles with very low fillet radii by the appropriate combination of the tooling contact pressure and selective laser heating of the bending zone. Laser heating also reduces the risk of rupture in both metals during bending at high angles, limits the springback extent up to 10 times on titanium and 30 times on aluminum in comparison with conventional bending process and does not affect significantly the visual appearance of the bending zone.

  8. Effect of the Femtosecond Laser on an Intracorneal Inlay for Surgical Compensation of Presbyopia during Cataract Surgery: Scanning Electron Microscope Imaging.

    Science.gov (United States)

    Ibarz, Marta; Rodríguez-Prats, Jose Luis; Hernández-Verdejo, Jose Luis; Tañá, Pedro

    2017-02-01

    To investigate the effect of the femtosecond laser-assisted cataract surgery (FLACS) on porcine eyes implanted with a Kamra corneal inlay and to describe how the inlay may change the effect of the femtosecond laser on the lens. FLACS was performed on six porcine eyes and a Kamra corneal inlay had been implanted, exploring the lens under the surgical microscope. Another Kamra corneal inlay was attached to the upper part of the transparent hemisphere used for calibration of the femtosecond laser. Capsulorhexis, arcuate incisions, and phacofragmentation were carried out. The Kamra corneal inlay was compared with a nontreated one using a scanning electron microscope (SEM), and the hemisphere was analyzed with a surgical microscope. Capsulorhexis and phacofragmentation were completed in all the porcine eyes, although accuracy to determine the exact effect on the lens was not possible to achieve. The effect of the femtosecond laser on the PMMA hemisphere through the Kamra corneal inlay showed the capsulorhexis was placed outside the outer margin of the inlay and a sharply sculpted fragmentation pattern with a three-dimensional (donut-shaped) annulus untreated beneath it. SEM images of the nontreated and the treated inlays were comparable. No ultrastructural changes were found in the treated Kamra corneal inlay. FLACS can be performed with a Kamra corneal inlay for surgical compensation of presbyopia without the risk of damaging the inlay. The Kamra corneal inlay acts as a screen that avoids the laser to reach the areas beneath its shadow, but not the exposed areas of the lens.

  9. Simultaneous Phacoemulsification and Graft Refractive Surgery in Penetrating Keratoplasty Eyes

    Science.gov (United States)

    Feizi, Sepehr; Zare, Mohammad; Einollahi, Bahram

    2011-01-01

    Purpose. To report outcomes of graft refractive surgery (GRS) along with clear-cornea phacoemulsification and intraocular lens (IOL) implantation in penetrating keratoplasty (PKP) eyes. Methods. Fourteen eyes of 13 patients who had received PKP underwent simultaneous GRS (relaxing incisions with or without counter-quadrant compression sutures) and clear-cornea phacoemulsification with IOL implantation. To calculate IOL power, preoperative keratometry readings and the SRK-T formula were used. Results. Mean patient age and follow-up period were 50.5 ± 14.4 years and 14.6 ± 7.1 months, respectively. A significant increase was observed in best spectacle-corrected visual acuity (from 0.55 ± 0.18 logMAR to 0.33 ± 0.18 logMAR, P = 0.001). There was a significant decrease in vector keratometric astigmatism by 6.22 D (P = 0.03). Spherical equivalent refraction was reduced from −3.31 ± 3.96 D to −1.69 ± 2.38 D (P = 0.02) which did not significantly differ from the target refraction (−0.76 ± 0.14 D, P = 0.20). No complications developed and all the grafts remained clear at the final examination. Conclusion. Simultaneous phacoemulsification and GRS is a safe and effective method to address post-PKP astigmatism and lens opacity. IOL power can be calculated from preoperative keratometry readings with an acceptable accuracy. However, patients should be informed about the possibility of high refractive errors postoperatively. PMID:24527227

  10. Intraocular Lens Calcifications After (Triple-) Descemet Membrane Endothelial Keratoplasty.

    Science.gov (United States)

    Schrittenlocher, Silvia; Penier, Marius; Schaub, Friederike; Bock, Felix; Cursiefen, Claus; Bachmann, Björn

    2017-07-01

    To identify incidence of and risk factors for calcifications of intraocular lenses (IOLs) after Descemet membrane endothelial keratoplasty (DMEK). Retrospective cohort study. Retrospective review of charts and slit-lamp images of 564 consecutive patients from the prospective Cologne DMEK database who underwent DMEK in pseudophakic eyes or DMEK in combination with cataract surgery (triple-DMEK) between September 3, 2013 and October 30, 2015 at the Department of Ophthalmology, University of Cologne. IOL calcifications after (triple-)DMEK occurred in 14 patients (2.5%). Visual acuities in affected and unaffected eyes were 0.33 ± 0.24 logMAR and 0.16 ± 0.01 logMAR after 3 months (P < .001) as well as 0.28 ± 0.16 logMAR and 0.13 ± 0.08 logMAR (P < .001) after 6 months, respectively. The proportions of triple-DMEK vs DMEK, the use of SF6 gas vs room air for anterior chamber tamponade, and the presence of hydrophilic vs hydrophobic acrylic IOLs were comparable in affected and unaffected eyes. Patients with IOL calcifications had higher rebubbling rates than patients without. Larger pupil diameters at the time of surgery showed a tendency to slightly larger areas of IOL calcifications. IOL calcifications after anterior chamber gas tamponade in DMEK lead to visual impairment and are associated with the number of rebubblings after DMEK. IOL calcifications also occur in hydrophobic acrylic IOLs. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Da Vinci Xi Robot-Assisted Penetrating Keratoplasty.

    Science.gov (United States)

    Chammas, Jimmy; Sauer, Arnaud; Pizzuto, Joëlle; Pouthier, Fabienne; Gaucher, David; Marescaux, Jacques; Mutter, Didier; Bourcier, Tristan

    2017-06-01

    This study aims (1) to investigate the feasibility of robot-assisted penetrating keratoplasty (PK) using the new Da Vinci Xi Surgical System and (2) to report what we believe to be the first use of this system in experimental eye surgery. Robot-assisted PK procedures were performed on human corneal transplants using the Da Vinci Xi Surgical System. After an 8-mm corneal trephination, four interrupted sutures and one 10.0 monofilament running suture were made. For each procedure, duration and successful completion of the surgery as well as any unexpected events were assessed. The depth of the corneal sutures was checked postoperatively using spectral-domain optical coherence tomography (SD-OCT). Robot-assisted PK was successfully performed on 12 corneas. The Da Vinci Xi Surgical System provided the necessary dexterity to perform the different steps of surgery. The mean duration of the procedures was 43.4 ± 8.9 minutes (range: 28.5-61.1 minutes). There were no unexpected intraoperative events. SD-OCT confirmed that the sutures were placed at the appropriate depth. We confirm the feasibility of robot-assisted PK with the new Da Vinci Surgical System and report the first use of the Xi model in experimental eye surgery. Operative time of robot-assisted PK surgery is now close to that of conventional manual surgery due to both improvement of the optical system and the presence of microsurgical instruments. Experimentations will allow the advantages of robot-assisted microsurgery to be identified while underlining the improvements and innovations necessary for clinical use.

  12. Phototherapeutic keratectomy for recurrent granular dystrophy in postpenetrating keratoplasty eyes

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2016-01-01

    Full Text Available Purpose: The purpose is to assess the clinical and visual outcome after phototherapeutic keratectomy (PTK procedure in eyes with prior penetrating keratoplasty (PKP for granular corneal dystrophy (GCD and the time of performance of repeat PTK for recurrence. Methods: PTK was performed for visually significant recurrence: A reduction in best-corrected visual acuity (BCVA by >2 lines over BCVA before recurrence was considered as visually significant recurrence. Three eyes had amniotic membrane patch performed with PTK. The main outcome measures were a recurrence of GCD, clinical course, and visual outcome. Intervals between repeat PTK procedures were noted. Results: Six patients (n = 10 eyes; males: 4, mean age 39 ± 13.97 years underwent PTK. The mean pachymetry before first PTK was 527.1 ± 34 microns. The mean duration between PKP and first PTK was 85.1 months (range: 37–108 months. Two and three PTK procedures were done for seven and five eyes, respectively. Mean duration between first and second and second and third PTK was 62.12 ± 34.41 and 42.8 ± 13.54 months respectively. The average cut depth was 43.66 ± 19.57, 75 ± 43.30 and 39 ± 19.79 microns after the first, second and third PTK procedures, respectively. All eyes had a corneal haze. Pre first PTK mean BCVA was 20/200 and improved significantly after the first two PTK procedures to 20/40 and after the third PTK procedure to 20/32 (P < 0.001. Five eyes had hyperopia. One acute graft rejection was managed successfully at 5 months with medical therapy. Conclusion: Multiple PTK procedures can be performed safely with improved visual acuity in grafts without compromising graft survival.

  13. Femtosecond laser induced microripple on PDMS surface

    Institute of Scientific and Technical Information of China (English)

    Jin Xie; Changhe Zhou; Wei Wang; Tengfei Wu

    2009-01-01

    laser pulses and the subsequent cool-down solidification of the melting PDMS along with the movement of the femtosecond laser spot. This result will be helpful to understand the interaction between the femtosecond laser and the polymer.

  14. Does Corneal Collagen Cross-linking Reduce the Need for Keratoplasties in Patients With Keratoconus?

    Science.gov (United States)

    Sandvik, Gunhild Falleth; Thorsrud, Andreas; Råen, Marianne; Østern, Atle E; Sæthre, Marit; Drolsum, Liv

    2015-09-01

    To investigate whether the introduction of corneal collagen cross-linking (CXL) influences the frequency of keratoplasties in patients with keratoconus. Data were obtained from a cohort of patients from our corneal transplant registry. Two different periods were compared, 2005 to 2006 (period 1) and 2013 to 2014 (period 2). Patients during period 1 had surgery before the introduction of CXL treatment, and patients in period 2 had surgery after this treatment was well established in our department. Age and gender were registered, and the Amsler-Krumeich classification system was applied to grade the degree of keratoconus. The total number of keratoplasties performed during period 1 was 137, and keratoconus was the cause of surgery in 55 eyes (55 patients). The corresponding numbers in period 2 were 231 and 26 eyes (26 patients), respectively. The difference in the number of keratoplasties for keratoconus in both periods was statistically significant (P = 0.003). There were no significant differences in the distributions of age and gender between both periods. In period 1, 63.6% of the eyes were graded as stage 4 in the Amsler-Krumeich classification, compared with 96.2% in period 2 (P = 0.001). The frequency of keratoplasty for keratoconus has been more than halved in our department over the last decade. There is reason to believe that this reduction is for a great part caused by the introduction of CXL treatment.

  15. Infectious crystalline keratopathy caused by Cladosporium sp. after penetrating keratoplasty: a case report

    Science.gov (United States)

    Stock, Ricardo Alexandre; Bonamigo, Elcio Luiz; Cadore, Emeline; Oechsler, Rafael Allan

    2016-01-01

    Background Infectious crystalline keratopathy is a rare, progressive infection characterized by the insidious progression of branches and crystalline corneal opacities with minimal or no inflammation. This case report describes the evolution of an infectious crystalline keratopathy caused by Cladosporium sp., which developed after tectonic keratoplasty in a patient with a history of ocular trauma. Case presentation A 40-year-old Brazilian male was the victim of firework-induced trauma to the left eye, which resulted in a corneal laceration that could not be sutured as well as a severe traumatic cataract. The patient underwent penetrating keratoplasty and phacoemulsification. During postoperative follow-up, another therapeutic keratoplasty was required because unresponsive infectious keratitis was observed. The infiltrate’s characteristics were suggestive of infectious crystalline keratopathy; in particular, the infiltrate was insidious and progressive, and grayish-white branches appeared in the anterior corneal stroma. As different therapies were administered, inflammatory reactions ranging from mild to severe were observed. The infection was unresponsive to typical antifungal drugs. This lack of response most likely occurred due to steroid treatment and the diffuse corneal spread of an atypical microorganism, which was subsequently identified in culture as Cladosporium sp. After the second therapeutic keratoplasty, the patient’s eye integrity was successfully reestablished. Conclusion This study likely provides the first report describing a case of infectious crystalline keratopathy caused by Cladosporium sp. This case emphasizes the clinical characteristics and outcome of this type of keratitis. PMID:27621671

  16. Effect of oral acyclovir after penetrating keratoplasty for herpetic keratitis: a placebo-controlled multicenter trial.

    NARCIS (Netherlands)

    Rooij, J.G.M. van; Rijneveld, W.J.; Remeijer, L.; Volker-Dieben, H.J.; Eggink, C.A.; Geerards, A.J.; Mulder, P.G.H.; Doornenbal, P.; Beekhuis, W.H.

    2003-01-01

    OBJECTIVE: To determine the prophylactic effect of oral acyclovir on the recurrence rate of herpetic eye disease after penetrating keratoplasty. DESIGN: A randomized, double-masked, placebo-controlled multicenter trial. PARTICIPANTS: Sixty-eight consecutive patients (68 eyes) with corneal opacities

  17. Diffraction efficiency enhancement of femtosecond laser-engraved diffraction gratings due to CO{sub 2} laser polishing

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hun-Kook [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Chosun University, Gwangju (Korea, Republic of); Jung, Deok; Sohn, Ik-Bu; Noh, Young-Chul; Lee, Yong-Tak [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Kim, Jin-Tae [Chosun University, Gwangju (Korea, Republic of); Ahsan, Shamim [Khulna University, Khulna (Bangladesh)

    2014-11-15

    This research demonstrates laser-assisted fabrication of high-efficiency diffraction gratings in fused-silica glass samples. Initially, femtosecond laser pulses are used to engrave diffraction gratings on the glass surfaces. Then, these micro-patterned glass samples undergo CO{sub 2} laser polishing process. unpolished diffraction gratings encoded in the glass samples show an overall diffraction efficiency of 18.1%. diffraction gratings imprinted on the glass samples and then polished four times by using a CO{sub 2} laser beam attain a diffraction efficiency of 32.7%. We also investigate the diffraction patterns of the diffraction gratings encoded on fused-silica glass surfaces. The proposed CO{sub 2} laser polishing technique shows great potential in patterning high-efficiency diffraction gratings on the surfaces of various transparent materials.

  18. Pediatric penetrating keratoplasty in Shanghai: a retrospective multiple centre study from 2003 to 2007

    Institute of Scientific and Technical Information of China (English)

    HONG Jia-xu; XU Jian-jiang; SHENG Min-jie; LIU Yan; ZHU Li

    2008-01-01

    Background With advances in pediatric keratoplasty over the last two decades, the success rate of surgery has increased remarkably. However, few epidemiological studies in this field have been performed in China. The present study investigated the indications and characteristics of pediatric penetrating keratoplasty in Shanghai.Methods All records of pediatric keratoplasty performed on 156 eyes in 149 children (<14 years) at four ophthalmic units in Shanghai during a 5-year period (2003-2007) were used for this retrospective study. Patients were from the Eye,Ear, Nose & Throat Hospital of Fudan University, Shanghai No.10 People's Hospital, Shanghai No.1 People's Hospital,and Shanghai Peace Ophthalmology Hospital; and included mostly school-age children (97 boys and 59 girls).Results The median age at surgery was 9 years with an interval quartile range of 6-12 years. Scarring after keratitis (29.5%, 46/156) and traumatic corneal scar (19.2%, 30/156) were the most common indications. Best Corrected Snellen visual acuity (BCSVA) was reported only in 72% (112/156) of cases. Visual acuity outcomes were significantly better for keratoplasty 1 year postoperatively compared to preoperative visual acuity (P=0.001). Of all patients, 13% (14/112) achieved a BCSVA of 6/18 or better. None of the indications was associated with a higher rate of failure compared to after 1 year follow-up.Conclusion We obtained valuable information on pediatric keratoplasty in Shanghai. There was no significant difference in graft survival rate among the two indications. Vision outcomes after corneal transplantation in Chinese children were significantly better compared with pre-operation status. In conclusion, corneal graft survival can be achieved in childhood.

  19. Infectious crystalline keratopathy caused by Cladosporium sp. after penetrating keratoplasty: a case report

    Directory of Open Access Journals (Sweden)

    Stock RA

    2016-08-01

    Full Text Available Ricardo Alexandre Stock,1 Elcio Luiz Bonamigo,2 Emeline Cadore,3 Rafael Allan Oechsler4 1Corneal Transplant Section, Santa Terezinha University Hospital, 2Department of Ophthalmology and Bioethics, 3University of Western Santa Catarina, Joaçaba, 4Cornea Department, Oftalmo Center Blumenau, Blumenau, Santa Catarina, Brazil Background: Infectious crystalline keratopathy is a rare, progressive infection characterized by the insidious progression of branches and crystalline corneal opacities with minimal or no inflammation. This case report describes the evolution of an infectious crystalline keratopathy caused by Cladosporium sp., which developed after tectonic keratoplasty in a patient with a history of ocular trauma.Case presentation: A 40-year-old Brazilian male was the victim of firework-induced trauma to the left eye, which resulted in a corneal laceration that could not be sutured as well as a severe traumatic cataract. The patient underwent penetrating keratoplasty and phacoemulsification. During postoperative follow-up, another therapeutic keratoplasty was required because unresponsive infectious keratitis was observed. The infiltrate’s characteristics were suggestive of infectious crystalline keratopathy; in particular, the infiltrate was insidious and progressive, and grayish-white branches appeared in the anterior corneal stroma. As different therapies were administered, inflammatory reactions ranging from mild to severe were observed. The infection was unresponsive to typical antifungal drugs. This lack of response most likely occurred due to steroid treatment and the diffuse corneal spread of an atypical microorganism, which was subsequently identified in culture as Cladosporium sp. After the second therapeutic keratoplasty, the patient’s eye integrity was successfully reestablished.Conclusion: This study likely provides the first report describing a case of infectious crystalline keratopathy caused by Cladosporium sp. This case

  20. Reduced myofibroblast differentiation on femtosecond laser treated 316LS stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Oberringer, Martin [Department of Trauma, Hand and Reconstructive Surgery, Saarland University, Homburg (Germany); Akman, Erhan [Laser Technologies Research and Application Center (LATARUM), Kocaeli University, Yenikoey/Kocaeli (Turkey); Lee, Juseok [CVD/Biosurfaces Division, INM - Leibniz Institute for New Materials, Saarbruecken (Germany); Metzger, Wolfgang [Department of Trauma, Hand and Reconstructive Surgery, Saarland University, Homburg (Germany); Akkan, Cagri Kaan [CVD/Biosurfaces Division, INM - Leibniz Institute for New Materials, Saarbruecken (Germany); Kacar, Elif [Laser Technologies Research and Application Center (LATARUM), Kocaeli University, Yenikoey/Kocaeli (Turkey); Demir, Arif [Laser Technologies Research and Application Center (LATARUM), Kocaeli University, Yenikoey/Kocaeli (Turkey); BEAM Ar-Ge Optic, Laser and Spectroscopy, KOU Technopark, Kocaeli, 41275 (Turkey); Abdul-Khaliq, Hashim [Clinic for Pediatric Cardiology, Saarland University Hospital, Homburg (Germany); Puetz, Norbert; Wennemuth, Gunther [Department of Anatomy and Cell Biology, Saarland University, Homburg (Germany); Pohlemann, Tim [Department of Trauma, Hand and Reconstructive Surgery, Saarland University, Homburg (Germany); Veith, Michael [CVD/Biosurfaces Division, INM - Leibniz Institute for New Materials, Saarbruecken (Germany); Aktas, Cenk, E-mail: cenk.aktas@inm-gmbh.de [CVD/Biosurfaces Division, INM - Leibniz Institute for New Materials, Saarbruecken (Germany)

    2013-03-01

    In-stent restenosis is a common complication after stent surgery which leads to a dangerous wall narrowing of a blood vessel. Laser assisted patterning is one of the effective methods to modify the stent surface to control cell-surface interactions which play a major role in the restenosis. In this current study, 316LS stainless steel substrates are structured by focusing a femtosecond laser beam down to a spot size of 50 {mu}m. By altering the laser induced spot density three distinct surfaces (low density (LD), medium density (MD) and high density (HD)) were prepared. While such surfaces are composed of primary microstructures, due to fast melting and re-solidification by ultra-short laser pulses, nanofeatures are also observed as secondary structures. Following a detailed surface characterization (chemical and physical properties of the surface), we used a well-established co-culture assay of human microvascular endothelial cells and human fibroblasts to check the cell compatibility of the prepared surfaces. The surfaces were analyzed in terms of cell adherence, proliferation, cell morphology and the differentiation of the fibroblast into the myofibroblast, which is a process indicating a general fibrotic shift within a certain tissue. It is observed that myofibroblast proliferation decreases significantly on laser treated samples in comparison to non-treated ones. On the other hand endothelial cell proliferation is not affected by the surface topography which is composed of micro- and nanostructures. Such surfaces may be used to modify stent surfaces for prevention or at least reduction of restenosis. - Highlights: Black-Right-Pointing-Pointer Reduced myofibroblast proliferation by micro- and nanotopography Black-Right-Pointing-Pointer Ultra-hydrophobic surfaces by femtosecond laser structuring Black-Right-Pointing-Pointer Micro- and nanostructuring of stainless steel surfaces by a femtosecond laser.

  1. Femtosecond photography lessons

    Science.gov (United States)

    Fanchenko, S. D.

    1999-06-01

    Antic scientists, sailors, warriors, physician, etc. were perceiving the space by means of their eye vision system. Nowadays the same people use eyeglasses, telescopes, microscopes, image converters. All these devices fit the necessary magnification, intensification gain and image spectrum to the eyes. The human brain is processing the image data offered to him in a format pertaining to eyes. Hence, the cognition of images can be regarded as a direct measurement. As to the time scale converters, they turned out to be harder done as compared with the spatial scale converters. Hence, the development of the high-speed photography (HSP) continues for more than a hundred and fifty years. The recent pico- femtosecond HSP branch sprang up in 1949 at the Kurchatov Institute -- its cradle. All about the HSP had been advertised. Instead of reprinting what is already well known, it makes sense to emphasize some instructive lessons drawn from past experience. Also it is tempting to look a bit into the high-speed photography future.

  2. Femtosecond optomagnetism in dielectric antiferromagnets

    Science.gov (United States)

    Bossini, D.; Rasing, Th

    2017-02-01

    Optical femtosecond manipulation of magnetic order is attractive for the development of new concepts for ultrafast magnetic recording. Theoretical and experimental investigations in this research area aim at establishing a physical understanding of magnetic media in light-induced non-equilibrium states. Such a quest requires one to adjust the theory of magnetism, since the thermodynamical concepts of elementary excitations and spin alignment determined by the exchange interaction are not applicable on the femtosecond time-scale after the photo-excitation. Here we report some key milestones concerning the femtosecond optical control of spins in dielectric antiferromagnets, whose spin dynamics is by nature faster than that of ferromagnets and can be triggered even without any laser heating. The recent progress of the opto-magnetic effect in the sub-wavelength regime makes this exciting research area even more promising, in terms of both fundamental breakthroughs and technological perspectives.

  3. Beating oscillation and Fano resonance in the laser assisted electron transmission through graphene δ-function magnetic barriers

    Science.gov (United States)

    Biswas, R.; Maity, S.; Sinha, C.

    2016-10-01

    We investigate theoretically the transmission of electrons through a pair of δ-function magnetic barriers in graphene in presence of external monochromatic, linearly polarized and CW laser field. The transmission coefficients are calculated in the framework of non-perturbative Floquet theory using the transfer matrix method. It is noted that the usual Fabry-Perot oscillations in transmission through the graphene magnetic barriers with larger inter barrier separation takes the shape of beating oscillations in presence of the external laser field. The laser assisted transmission spectra are also found to exhibit the characteristic Fano resonances (FR) for smaller values of the inter barrier separation. The appearance of the perfect node in the beating oscillation and the asymmetric Fano line shape can be controlled by varying the intensity of the laser field. The above features could provide some useful and potential information about the light - matter interactions and may be utilized in the graphene based optoelectronic device applications.

  4. Numerical Investigation of Laser-Assisted Nanoimprinting on a Copper Substrate from a Perspective of Heat Transfer Analysis

    CERN Document Server

    Jen, Chun-Ping

    2008-01-01

    The technique of laser-assisted nanoimprinting lithography (LAN) has been proposed to utilize an excimer laser to irradiate through a quartz mold and melts a thin polymer film on the substrate for micro- to nano-scaled fabrications. In the present study, the novel concept of that copper was adopted as the substrate instead of silicon, which is conventionally used, was proposed. The micro/nano structures on the copper substrate could be fabricated by chemical/electrochemical etching or electroforming ; following by the patterns have been transferred onto the substrate using LAN process. Alternatives of the substrate materials could lead versatile applications in micro/nano-fabrication. To demonstrate the feasibility of this concept numerically, this study introduced optical multiple reflection theory to perform both analytical and numerical modeling during the process and to predict the thermal response theoretically.

  5. Changing indications for lamellar keratoplasty in Shandong,1993-2008

    Institute of Scientific and Technical Information of China (English)

    QU Li-jun; XIE Li-xin

    2010-01-01

    Background With the advancement of microsurgical techniques, lamellar keratoplasty (LK) has been more valued and performed to treat corneal blindness. This study aimed to evaluate the indications and changing trends for LK during the past 16 years in Shandong Eye lnstitute, an eye center in China.Methods A total of 1529 eyes, predominantly from male (70.7%) patients undergoing LK between January 1993 and December 2008, were enrolled in this study. Data were collected by reviewing patient medical records for demographic characteristics, clinical diagnosis, laboratory findings and risk factors. Surgical times, initial diagnoses and causes of regrafting were recorded. All LKs were sequentially divided into period 1 (from 1993 to 2000) and period 2 (from 2001 to 2008).Results Rural-dwelling patients in this study numbered 1089 (71.2%); in all cases of infectious keratitis, rural patients accounted for 90.5%. The leading indications for LK were infectious keratitis (31.0%), corneal trauma (21.1%),keratoconus (18.7%), corneal dystrophy and degeneration (7.3%), regrafting (7.1%), immunologic disorders (6.7%),congenital abnormalities and corneal tumor (4.1%) and corneal scarring (3.1%). The most common subcategory of infectious keratitis was fungal keratitis (67.5%). Fusarium solani was the most morbigenous fungi. Among the patients,73.1% of thermal burns were caused by hot molten metal, and 47.8% of alkali burns by lime. Dermoid was the most common indication for congenital abnormalities. The two main initial diagnoses from 109 regrafting cases were corneal trauma (45.9%) and Mooren's ulcer (27.5%). The most common cause for regrafting was immune rejection (35.8%).lnfectious keratitis was the most common indication for LK from 16.0% in period 1 to 41.1% in period 2, followed by keratoconus (16.8%) and corneal trauma (14.5%).Conclusions During the past 16 years, there have been major changes in the constituent ratios of leading indications for LK in Shangdong. Infectious

  6. Impact of different vehicles for laser-assisted drug permeation via skin: full-surface versus fractional ablation.

    Science.gov (United States)

    Lee, Woan-Ruoh; Shen, Shing-Chuan; Aljuffali, Ibrahim A; Li, Yi-Ching; Fang, Jia-You

    2014-02-01

    This study aimed to assess impact of different vehicles for laser-assisted skin drug delivery. We also tried to uncover the mechanisms by which different vehicles affect laser-aided skin permeation. Full-surface ablative (conventional) and fractional lasers were used to irradiate nude mouse skin. Imiquimod and 5-aminolevulinic acid (ALA) were used as lipophilic and hydrophilic permeants. Vehicles employed included water with 40% polyethylene glycol 400 (PEG 400), propylene glycol (PG), and ethanol. Lipid nanoparticles were also utilized as carriers. In vitro permeation profiles showed improvement in imiquimod flux with conventional laser (2.5 J/cm2) producing a 12-, 9-, and 5-fold increase when loading imiquimod in 40% PEG400, PG, and ethanol, respectively, as compared with intact skin. Nanoparticulate delivery by laser produced a 6-fold enhancement in permeation. Fractional laser produced less enhancement of imiquimod delivery than conventional laser. Laser exposure increased follicular imiquimod accumulation from 0.80 to 5.81 μg/cm2. ALA permeation from aqueous buffer, PEG 400, and PG with conventional laser treatment was 641-, 445-, and 104-fold superior to passive control. In vivo skin deposition of topically applied ALA examined by confocal microscopy indicated the same trend as the in vitro experiment, with aqueous buffer showing the greatest proporphyllin IX signaling. Diffusion of cosolvent molecules into ablated skin and drug partitioning from vehicle to skin are two predominant factors controlling laser-assisted delivery. In contrast to conventional laser, lateral drug diffusion was anticipated for fractional laser. Our results suggest that different drug delivery vehicles substantially influence drug penetration enhanced by lasers.

  7. Long-pulsed Nd:YAG laser-assisted hair removal in Fitzpatrick skin types IV-VI.

    Science.gov (United States)

    Rao, Krishna; Sankar, Thangasamy K

    2011-09-01

    Unwanted hair is a common problem for which a variety of laser treatments is available. Laser treatment in dark-skinned individuals carries a higher risk of complications like hyperpigmentation and burn. The objective of this study was to evaluate efficacy and safety profile of laser-assisted hair removal in individuals with Fitzpatrick type IV-VI skin using long-pulsed Nd:YAG laser. Retrospective data was collected from 150 individuals with Fitzpatrick type IV-VI skin who underwent laser-assisted hair removal. This included area treated, fluence, number of treatments, and outcome. Data was also gathered on patient satisfaction and complications. The most common phototype was type IV (94%). The most frequently treated area was the face (84.7%) followed by the underarms and legs. Among the facial areas, the chin was the most frequently treated area followed by the upper lip and jaw line. The mean number of treatments was 8.9 (range 4-22). The maximum fluence averaged 26.8 Joules/cm(2) and was significantly higher for facial hair. Of the patients, 78.7% felt that their treatment was good or satisfactory. Mean hair reduction was 54.3%. Satisfaction from the treatment was significantly higher in individuals undergoing treatment of non-facial areas. Subsequent hair growth was slower and finer in 79.3% of the patients. There were no complications in 86% of the patients. All the complications were transient, with hyperpigmentation being the most frequent complication. Our results show that laser hair removal using the long-pulsed Nd:YAG laser is safe and effective in dark-skinned individuals with satisfactory results in most patients.

  8. Femtosecond Fiber Lasers

    Science.gov (United States)

    Bock, Katherine J.

    This thesis focuses on research I have done on ytterbium-doped femtosecond fiber lasers. These lasers operate in the near infrared region, lasing at 1030 nm. This wavelength is particularly important in biomedical applications, which includes but is not limited to confocal microscopy and ablation for surgical incisions. Furthermore, fiber lasers are advantageous compared to solid state lasers in terms of their cost, form factor, and ease of use. Solid state lasers still dominate the market due to their comparatively high energy pulses. High energy pulse generation in fiber lasers is hindered by either optical wave breaking or by multipulsing. One of the main challenges for fiber lasers is to overcome these limitations to achieve high energy pulses. The motivation for the work done in this thesis is increasing the output pulse peak power and energy. The main idea of the work is that decreasing the nonlinearity that acts on the pulse inside the cavity will prevent optical wave breaking, and thus will generate higher energy pulses. By increasing the output energy, ytterbium-doped femtosecond fiber lasers can be competitive with solid state lasers which are used commonly in research. Although fiber lasers tend to lack the wavelength tuning ability of solid state lasers, many biomedical applications take advantage of the 1030 microm central wavelength of ytterbium-doped fiber lasers, so the major limiting factor of fiber lasers in this field is simply the output power. By increasing the output energy without resorting to external amplification, the cavity is optimized and cost can remain low and economical. During verification of the main idea, the cavity was examined for possible back-reflections and for components with narrow spectral bandwidths which may have contributed to the presence of multipulsing. Distinct cases of multipulsing, bound pulse and harmonic mode-locking, were observed and recorded as they may be of more interest in the future. The third

  9. A comparative study of internal laser-assisted and conventional liposuction: a look at the influence of drugs and major surgery on laboratory postoperative values

    Directory of Open Access Journals (Sweden)

    Przylipiak AF

    2013-10-01

    Full Text Available Andrzej Feliks Przylipiak,1 Elżbieta Galicka,1 Magdalena Donejko,1 Marek Niczyporuk,1 Jerzy Przylipiak21Department of Aesthetic Medicine, Faculty of Pharmacy, Medical University of Bialystok, Bialystok, Poland; 2Medical Office, Bialystok, PolandBackground: Liposuction is a type of aesthetic surgery that has been performed on humans for decades. There is not much literature addressing the subject matter of pre- and post-surgery blood parameters, although this information is rather interesting. Documentation on patients who received laser-assisted liposuction treatment is particularly scarce. Until now, there has been no literature showing values of platelets, lymphocytes, and neutrophils after liposuction.Purpose: The aim of the work is to analyze and interpret values of platelets, lymphocytes and neutrophils in patient blood before and after liposuction, a surgery in which an extraordinarily large amount of potent drugs are used. Moreover, the aim is to compare values changes in patients of conventional and laser-assisted liposuction.Material and methods: We evaluated standard blood samples in patients prior to and after liposuction. This paper covers the number of platelets, lymphocytes, and neutrophils. A total of 54 patients were examined. Moreover, we compared the change in postoperative values in laser-assisted liposuction patients with the change of values in conventional liposuction patients. A paired two-sided Student's t-test was used for statistical evaluation. P < 0.005 was acknowledged to be statistically significant.Results: Values of platelets were raised both in conventional and in laser-assisted liposuction patients, but this difference was statistically non-significant and levels of platelets were still normal and within the range of blood levels in healthy patients. Values of neutrophils rose by up to 79.49% ± 7.74% standard deviation (SD and values of lymphocytes dropped by up to 12.68% ± 5.61% SD. The before

  10. STUDY OF THE ANATOMICAL AND VISUAL RESULTS OF THERAPEUTIC PENETRATING KERATOPLASTY

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    Chhaya Ashok Shinde

    2017-03-01

    Full Text Available BACKGROUND Therapeutic penetrating keratoplasty for corneal infections restores anatomical integrity. Improvement in instrumentation and surgical techniques, better postoperative management have improved corneal transplant outcome. Purpose of the study was to know what are the anatomical and visual results after therapeutic keratoplasty and to judge what could be the factors affecting the results. MATERIALS AND METHODS Prospective, non-comparative, observational cohort study was done in 56 patient (56 eyes operated for therapeutic penetrating keratoplasty at tertiary care institute .Patients were reviewed for demographic data, postoperative best-corrected visual acuity, graft clarity, and complications. Pre-operative treatment in bacterial infections included Cefazolin 50 mg/ml and Tobramycin 1.4 % or gentamicin 1.4% half hourly, 1% atropine drops. Fungal infections were treated with Natamycin 5% suspension. Debridement was done. Amphotericin B was used against yeasts. Voriconazole (1% eye drops were given in Aspergillus species. With full aseptic precautions penetrating keratoplasty was carried out. The graft was 0.5 mm larger than the lesion. Keratoplasties were evaluated for (1 Graft clarity at 1 month and 1 year postoperative. (2 Cure of the infectious disease after surgery. (3 Anatomical success rate and visual results. RESULTS At the end of one year clear graft with bacterial keratitis was seen in 23 eyes (74.19% out of 31 eyes. In fungal keratitis clear graft was seen in 10 eyes (45.45% out of 22 eyes. 48.22% patients had vision of FC 1m-6/60 compared to preoperative vision at the end of one year. At the end of one year anatomical integrity was maintained in 53 (94.64% cases and it was lost in 5.36% patients. CONCLUSION Patients who underwent keratoplasty with 7.5 mm graft size had maximum graft clarity at the end of one year. Graft was clear in 36 patients (64.29% out of total 56 patients. At the end of 1 year vision improved to FC 1 mt

  11. Simultaneous bilensectomy and endothelial keratoplasty for angle-supported phakic intraocular lens-induced corneal decompensation

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    Vikas Mittal

    2011-01-01

    Full Text Available A 40-year-old lady presented with severe endothelial cell loss in both eyes 14 years after angle-supported phakic intraocular lens (AS PIOL implantation. The left eye had severe corneal edema with bullous keratopathy. The right eye had markedly reduced endothelial cell count (655 cells/mm 2 although the cornea was clear. She underwent simultaneous bilensectomy (AS PIOL explantation and phacoemulsification and Descemet′s stripping and endothelial keratoplasty (DSEK in the left eye. Explanted AS PIOL was identified as ZSAL-4 (Morcher, Stuttgart, Germany model. Corneal edema cleared completely in 2 months with a best corrected visual acuity (-2.25 D sph of 20/60. No intervention was done in the right eye. The present case illustrates that AS PIOL-induced endothelial decompensation can be effectively managed by simultaneous bilensectomy and endothelial keratoplasty.

  12. Tectonic deep anterior lamellar keratoplasty in impending corneal perforation using cryopreserved cornea.

    Science.gov (United States)

    Jang, Ji Hye; Chang, Sung Dong

    2011-04-01

    We report a case of tectonic corneal transplantation for impending corneal perforation to preserve anatomic integrity using cryopreserved donor tissue. An 82-year-old woman exhibiting impending corneal perforation suffered from moderate ocular pain in the left eye for one week. After abnormal tissues around the impending perforation area were carefully peeled away using a Crescent blade and Vannas scissors, the patient received tectonic deep anterior lamellar keratoplasty using a cryopreserved cornea stored in Optisol GS® solution at -70℃ for four weeks. At six months after surgery, the cornea remained transparent and restored the normal corneal thickness. There were no complications such as corneal haze or scars, graft rejection, recurrent corneal ulcer, and postoperative rise of intraocular pressure. Cryopreserved donor lamellar tissue is an effective substitute in emergency tectonic lamellar keratoplasty, such as impending corneal perforation and severe necrotic corneal keratitis.

  13. AcrySof toric intraocular lens for post-keratoplasty astigmatism

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    Nishant Gupta

    2012-01-01

    Full Text Available We report a 63-year-old male who had undergone left eye optical penetrating keratoplasty for central leucomatous corneal opacity 10 years earlier. The eye had clear donor graft with residual astigmatism of −6.50 diopter cylinder (DC at 30°. The patient underwent clear corneal phacoemulsification with implantation of +6.0 D spherical equivalent AcrySof SN60T9 intraocular lens (IOL. Postoperatively, at 10 months, the patient had distance corrected visual acuity of 20/30 with −2.00 DC at 20°. AcrySof toric IOL offers an effective treatment option for post-keratoplasty high corneal astigmatism in patients with cataract.

  14. Demonstration of cornea Dua's layer at a deep anterior lamellar keratoplasty surgery

    OpenAIRE

    Yusuf Kocluk; Ayse Burcu; Emine Alyamac Sukgen

    2016-01-01

    The authors aimed to present a deep anterior lamellar keratoplasty (DALK) surgery case with mixed type bubble demonstrating Dua′s layer (DL). This was a reported case of DALK surgery. The authors encountered cornea DL structure at DALK surgery while cleaning the remaining stromal pieces. We also observed perforation in the central part of DL. However, DALK surgery could be completed. It is possible to encounter DL in a DALK surgery performed with mixed type big-bubble.

  15. Demonstration of cornea Dua′s layer at a deep anterior lamellar keratoplasty surgery

    Directory of Open Access Journals (Sweden)

    Yusuf Kocluk

    2016-01-01

    Full Text Available The authors aimed to present a deep anterior lamellar keratoplasty (DALK surgery case with mixed type bubble demonstrating Dua′s layer (DL. This was a reported case of DALK surgery. The authors encountered cornea DL structure at DALK surgery while cleaning the remaining stromal pieces. We also observed perforation in the central part of DL. However, DALK surgery could be completed. It is possible to encounter DL in a DALK surgery performed with mixed type big-bubble.

  16. Inadequate results for microkeratome-assisted additive stromal keratoplasty for management of keratoconus.

    Science.gov (United States)

    Coullet, Julien; Fournié, Pierre; Malecaze, François; Arné, Jean-Louis

    2008-02-01

    To evaluate a new automated technique--microkeratome-assisted additive stromal keratoplasty (MASK)--for the management of keratoconus in eyes scheduled for surgery with clear cornea associated with total contact lens intolerance. This non-comparative, interventional case series included four eyes of four patients with stage I and II keratoconus associated with total contact lens intolerance. The first step of the surgical procedure consisted of performing a nasal-hinged flap on the host cornea with a microkeratome. The second step consisted of extracting a stromal piano-powered disk from the donor's cornea using an artificial chamber. The 80-microm thick lamellar graft was punched with a 7.5-mm circular trephine and positioned beneath the flap. Corneal refractive surgery was scheduled for the end of the sixth postoperative month. No corneal refractive surgery was performed after 6 months of follow-up. Only one eye gained five lines of best spectacle-corrected visual acuity (BSCVA). Among the other three eyes, two had unchanged BSCVA and one lost one line of BSCVA. At the end of surgery, mean corneal thickness was increased by 148.75 microm. Microkeratome-assisted additive stromal keratoplasty appears to be a safe and straightforward surgical technique that preserves the host endothelium and avoids the need of an open-sky procedure. However, in our study, MASK is not considered as an alternative to penetrating or deep lamellar keratoplasty in the management of keratoconus with clear cornea because of imprecise anatomic and refractive outcomes.

  17. Donor cornea preparation in partial big bubble deep anterior lamellar keratoplasty

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    Lim L

    2014-02-01

    Full Text Available Li Lim,1 Samuel Wen Yan Lim21Corneal and External Eye Disease Service, Singapore National Eye Centre, 2Yong Loo Lin School of Medicine, National University of Singapore, SingaporeBackground: The purpose of this paper is to describe a technique of donor cornea preparation to ensure good graft-host apposition in incomplete big bubble deep anterior lamellar keratoplasty.Methods: Following a partial-thickness trephination, manual dissection and excision of corneal stroma was performed. Anwar's big-bubble technique involving a deep stromal air injection was then initiated. However, the big bubble could not extend to the trephination edge and the peripheral residual corneal stroma could not be removed. Donor cornea preparation involving trimming of the posterior lip of the corneal button was then performed and good graft-host apposition was obtained without graft over-ride.Results: We performed peripheral donor cornea trimming prior to allograft placement in order to ensure good graft-host apposition. Postoperatively, best-corrected visual acuity in both eyes was 6/7.5.Conclusion: Donor cornea preparation involving trimming of the posterior lip of the corneal button is a useful technique in instances where the big bubble does not extend to the trephination edge and ensures good graft-host apposition.Keywords: deep anterior lamellar keratoplasty, incomplete Anwar big bubble deep anterior lamellar keratoplasty, donor cornea preparation

  18. New stroboscopic light source and technique for intraoperative retinal fluorescein angiography during penetrating keratoplasty

    Science.gov (United States)

    Krueger, Ronald R.; Morales, Ronald B.; Chong, Lawrence P.; Smith, Ronald E.

    1994-06-01

    We report the development of a new stroboscopic light source system and technique for performing intraoperative fluorescein angiography during penetrating keratoplasty for aphakic or pseudophakic bullous keratopathy. A controllable pulse xenon light source system with a fiber optic endoilluminator probe is used to perform high-quality intraoperative fluorescein angiography during penetrating keratoplasty in pigmented rabbits and human subjects. Following corneal trephination and extraction of the intraocular lens, a temporary Cobo keratoprosthesis is secured while a 20-gauge endoilluminator is inserted into the vitreous cavity through a limbal incision. The endoilluminator is advanced to a retinal illumination area of approximately 3 DD and 10% fluorescein is injected intravenously. A microscope camera coupled to a 50:50 beamsplitter photographs the passage of fluorescein dye while the surgeon maintains an unaltered view through the operating microscope. Angiograms through a keratoprosthesis show excellent contrast and resolution, comparable to standard fluorescein angiography. Fine peripapillary vessels are seen reproducibly and with great detail in the rabbits. All the phases of retinal angiography can be seen, including arteriolar constriction and capillary nonperfusion in one of four human subjects examined. High quality intraoperative fluorescein angiography can be performed in patients undergoing penetrating keratoplasty for aphakic/ pseudophakic bullous keratopathy. With this technology, preexisting retinal disorders such as cystoid macular edema might be identified in the perioperative setting allowing for important management decisions to be made intraoperatively.

  19. Keratorefractive Effect of High Intensity Focused Ultrasound Keratoplasty on Rabbit Eyes

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    Zhiyu Du

    2016-01-01

    Full Text Available Purpose. To evaluate high intensity focused ultrasound (HIFU as an innovation and noninvasive technique to correct presbyopia by altering corneal curvature in the rabbit eye. Methods. Eighteen enucleated rabbit eyes were treated with a prototype HIFU keratoplasty. According to the therapy power, these eyes were divided three groups: group 1 (1 W, group 2 (2 W, and group 3 (3 W. The change in corneal power was quantified by a Sirius Scheimpflug camera. Light microscopy (LM and transmission electron microscopy (TEM were performed to determine the effect on the corneal stroma. Results. In the treated eyes, the corneal curvature increases from 49.42 ± 0.30 diopters (D and 48.00 ± 1.95 D before procedure to 51.37 ± 1.11 D and 57.00 ± 1.84 D after HIFU keratoplasty application in groups 1 and 3, respectively. The major axis and minor axis of the focal region got longer when the powers of the HIFU got increased; the difference was statistically significant (p<0.05. LM and TEM showed HIFU-induced shrinkage of corneal stromal collagen with little disturbance to the underlying epithelium. Conclusions. We have preliminarily exploited HIFU to establish a new technique for correcting presbyopia. HIFU keratoplasty will be a good application prospect for treating presbyopia.

  20. Laser-assisted skin closure at 1.32 microns: the use of a software-driven medical laser system

    Science.gov (United States)

    Dew, Douglas K.; Hsu, Tung M.; Hsu, Long S.; Halpern, Steven J.; Michaels, Charles E.

    1991-06-01

    This study investigated the use of a computerized 1 .3 micron Nd:YAG laser to seal approximated wound edges in pig skin. The medical laser system used was the DLS Type 1 , 1 .32 micron Nd:YAG laser (Laser Surgery Software, Inc.). The purpose of this study was to evaluate the effectiveness of laser assisted skin closure using the DLS YAG laser in a large animal model. Effectiveness was judged on the basis of wound dehiscence, infection, unusual healing result and consistency of results. Comparative cosmetic result was also evaluated. In this study, the DLS YAG laser was used to close scalpel-induced, full-thickness wounds. The pig model was chosen for its many integumentary similarities to man. Controls included scalpel-induced wounds closed using suture, staple and some with norepair. After adequate anesthesia was achieved, the dorsum of Yucutan pigs (approximately 75- 100 pounds) each was clipped with animal hair clippers from the shoulder area to the hind legs. The area was then shaved with a razor blade, avoiding any inadvertent cuts or abrasions of the skin. The dorsum was divided into four rows of four parallel incisions made by a #15 scalpel blade. Full-thickness incisions, 9 cm long, were placed over the dorsum of the pigs and then closed either with one loosely approximating Prolene" suture (the "no repair' group), multiple interrupted 6-0 nylon sutures, staples or laser. The experimental tissue sealing group consisted of 1 69 laser assisted closures on 1 3 pigs. Sutured control wounds were closed with 6-0 nylon, full thickness, simple, interrupted sutures. Eight sutures were placed 1 cm apart along the 9 cm incision. Stapled control wounds were approximated using two evenly spaced 3-0 VicryP' sub-dermal sutures and the dermis closed using Proximate' skin staples. Eight staples were placed 1 cm apart along the 9 cm incision. The no-repair incisions were grossly approximated using a single 2-0 Prolene full thickness, simple, interrupted suture located at the

  1. Outcome of therapeutic penetrating keratoplasty in a tertiary eye care center in Nepal

    Directory of Open Access Journals (Sweden)

    Bajracharya L

    2015-12-01

    Full Text Available Leena Bajracharya, Reeta Gurung Department of Cornea, Tilganga Institute of Ophthalmology, Kathmandu, Nepal Background: Corneal ulcer is an important cause of blindness in developing countries. Therapeutic keratoplasty for infective keratitis is a frequently performed surgery in these countries.Objective: To find out the outcome of therapeutic keratoplasty for infective keratitis.Methods: Records of 5 years were reviewed of patients who underwent therapeutic keratoplasty from 2006 to 2010. Data collected included demographic parameters, indications for surgery, microbiology of the ulcers, type of surgery performed, and donor tissue details. In the follow-up period, ocular status was evaluated in terms of eradication of disease, anatomic success, graft clarity, visual acuity, and development of glaucoma and cataract.Results: In all, 180 eyes of 180 patients were enrolled in the study; 59.4% of the patients were male. Average age was 44.4±16.7 years. Overall, 71% of infective keratitis was perforated. A total of 101 (56% eyes were positive for organisms of which 49 showed pure fungus and 49 showed pure bacteria. The commonest fungus and bacteria isolated were Aspergillus and Streptococcus, respectively. Average follow-up period was 29±23 months. Overall cure rate of infection was 88.8%, anatomical success rate was 89.5%, and graft clarity was 37.2%. Overall, 43.4% had secondary glaucoma. In the postoperative course, 65.8% of phakic eyes had developed cataract. In all, 38.6% of graft had endothelial failure and 24% of the graft failed due to late infective keratitis. Overall functional success with a visual acuity above 6/60 was 25.4%. Bacterial keratitis had a significantly higher cure rate, anatomical success, and graft clarity compared to fungal keratitis.Conclusion: Therapeutic keratoplasty is an important procedure to save the eye and preserve vision in severe infective keratitis. There is a high incidence of postoperative glaucoma

  2. Dynamics of Femtosecond Electron Bunches

    OpenAIRE

    Khachatryan, A. G.; Irman, A.; van Goor, F. A.; Boller, K. -J.

    2007-01-01

    In the laser wakefield accelerator (LWFA) a short intense laser pulse, with a duration of the order of a plasma wave period, excites an unusually strong plasma wake wave (laser wakefield). Recent experiments on laser wakefield acceleration [Nature (London) 431, p.535, p.538, p.541 (2004)] demonstrated generation of ultra-short (with a duration of a few femtoseconds) relativistic electron bunches with relatively low energy spread of the order of a few percent. We have studied the dynamics of s...

  3. Thickness dependence of electrical properties of PZT films deposited on metal substrates by laser-assisted aerosol deposition.

    Science.gov (United States)

    Baba, S; Tsuda, H; Akedo, J

    2008-05-01

    Dependence of electrical properties-dielectric, ferroelectric, and piezoelectric properties-on film thickness was studied for lead-zirconate titanate (PZT) thick films directly deposited onto stainless-steel (SUS) substrates in actuator devices by using a carbon dioxide (CO(2) ), laser assisted aerosol deposition technique. Optical spectroscopic analysis data and laser irradiation experiments revealed that absorption at a given wavelength by the film increased with increasing film thickness. Dielectric constant epsilon, remanent polarization value P(r), and coercive field strength E(c) of PZT films directly deposited onto a SUS-based piezoelectric actuator substrate annealed by CO(2) laser irradiation at 850 degrees C improved with increasing film thickness, and for films thicker than 25 microm, epsilon 800, P(r) 40 microC/cm(2), and E(c) 45 kV/cm. In contrast, the displacement of the SUS-based actuator with the laser-annealed PZT thick film decreased with increasing film thickness.

  4. Ambulatory treatment of sleep apnea syndrome with CO2 laser: laser-assisted UPPP (LAUP), results on 70 patients

    Science.gov (United States)

    Kamami, Yves-Victor

    1995-05-01

    The pharyngeal airway obstruction during sleep in the Obstructive Sleep Apnea Syndrome (OSAS) can be improved after treatment by LAUP (Laser Assisted Uvulopalatoplasty). This new technique, performed under local anesthesia, permits the snoring treatment without any hospitalization, or general anesthetic; like an ordinary dental visit. This is done by reducing the amount of tissue in the uvula, the velum, and the upper part of the posterior pillars. Our experience with the LAUP in Sleep Apnea Syndrome is described, from December 1988 to May 1994, in 70 patients. Among 62 patients classified as successful `responders', the respiratory disturbance index was reduced more than 50%. Among all the 70 patients: in 51.4 % of cases (36 patients), there's a healing of snoring and Sleep Apnea Syndrome. In 37.2% of cases (26 patients), there's an improvement reduction of length and number of apneas and a significant improvement in nocturnal oxygen saturation. 11.4% (8 patients), are relative failures, with always decrease of snoring, but still Sleep Apnea Syndrome, (with a higher B.M.I.). There were no important complications reported. Patients withstand it well and there's had a better tolerance of the C.P.A.P. in the cases of OSAS LRPP failures. Popularization of LAUP will require serious training of surgeon and further long-term studies.

  5. Ambulatory treatment of snoring with CO2 laser: laser-assisted UPPP (LAUP), results on 856 patients

    Science.gov (United States)

    Kamami, Yves-Victor

    1995-05-01

    The usual treatment of snoring in the absence of sleep apneas has been UPPP. Patients are often reluctant to undergo this painful procedure under general anesthesia. The Laser Assisted Uvulopalatoplasty (LAUP) is a new procedure, introduced six years ago by the author, using local anesthesia for the treatment of snoring in an office setting. This technique is designed to correct breathing abnormalities during sleep, caused by pharyngeal airway obstruction in patients suffering of Snoring or Obstructive Sleep Apnea Syndrome. This is done by reducing the amount of tissue in the uvula, the velum, and the upper part of the posterior pillars. LAUP allows surgery for the relief of snoring to be performed in the office, under local anesthesia. LAUP has many advantages over the traditional UPPP. It is simple, reliable, hemostatic, and less painful. It is also less expensive as it can be performed as an outpatient. This makes the LAUP more accessible to patients. Our experience with LAUP in 856 patients from December 1988 to July 1994 (141 women and 715 men) is described. Good results were obtained in 94.8% of patients and there were no complications. This new technique can be easily performed by other otolaryngologists after serious suitable training. LAUP provides a simple alternative for many patients who do not wish to undergo a traditional UPPP.

  6. Excimer laser assisted re-oxidation of BaTiO{sub 3} thin films on Ni metal foils

    Energy Technology Data Exchange (ETDEWEB)

    Bharadwaja, S. S. N., E-mail: s.s.n.bharadwaja@gmail.com; Ko, S. W.; Qu, W.; Clark, T. [Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Rajashekhar, A. [Materials Science and Engineering Department, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Motyka, M. [Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Podraza, N. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606 (United States); Randall, C. A.; Trolier-McKinstry, S. [Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Materials Science and Engineering Department, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2016-01-14

    Excimer laser assisted re-oxidation for reduced, crystallized BaTiO{sub 3} thin films on Ni-foils was investigated. It was found that the BaTiO{sub 3} can be re-oxidized at an oxygen partial pressure of ∼50 mTorr and substrate temperature of 350 °C without forming a NiO{sub x} interface layer between the film and base metal foil. The dielectric permittivity of re-oxidized films was >1000 with loss tangent values <2% at 100 Hz, 30 mV{sub rms} excitation signal. Electron Energy Loss Spectroscopy indicated that BaTiO{sub 3} thin films can be re-oxidized to an oxygen stoichiometry close to ∼3 (e.g., stoichiometric). High resolution cross sectional transmission electron microscopy showed no evidence of NiO{sub x} formation between the BaTiO{sub 3} and the Ni foil upon excimer laser re-oxidation. Spectroscopic ellipsometry studies on laser re-oxidized [001]{sub C} and [111]{sub C} BaTiO{sub 3} single crystals indicate that the re-oxidation of BaTiO{sub 3} single crystals is augmented by photo-excitation of the ozone, as well as laser pulse induced temperature and local stress gradients.

  7. Laser-assisted direct joining of AISI304 stainless steel with polycarbonate sheets: Thermal analysis, mechanical characterization, and bonds morphology

    Science.gov (United States)

    Lambiase, F.; Genna, S.

    2017-02-01

    Laser-Assisted Metal and Plastic bonding (LAMP) of AISI304 sheets with polycarbonate sheets is investigated in this work. The process was performed by means of a high power diode laser with a maximum power of 200 W. The study introduces an integrated experimental approach aimed at understanding how the main process conditions (laser power and scanning speed) influence the direct-bonds quality, dimensions and presence of defects. To this end, the bonds dimension, shear strength, formation and dimension of bubbles in the bonded region were related to the temperature measurements and process parameters. According to the achieved results, the processing window that enables a good adhesion of the two materials is relatively small; this is due the activation of the adhesion phenomena that require overcoming an energy threshold. However, excessive energy levels reduce the bonds strength due to the increase in defects (bubbles) dimension that may combine (coalescence) leading to the formation of a central tunnel where the two substrates are completely detached.

  8. Preparation, characterisation and optimisation of lithium battery anodes consisting of silicon synthesised using Laser assisted Chemical Vapour Pyrolysis

    Science.gov (United States)

    Veliscek, Ziga; Perse, Lidija Slemenik; Dominko, Robert; Kelder, Erik; Gaberscek, Miran

    2015-01-01

    Suitability of silicon prepared using Laser assisted Chemical Vapour Pyrolysis (LaCVP) as a potential anode material in lithium batteries is systematically investigated. Its compositional, morphological, physical-chemical and electrochemical properties are compared to a current benchmark commercial silicon. Important differences in particle size and particle composition are found which, as shown, affect critically the rheological properties of the corresponding electrode slurries. In order to overcome the rheological problems of prepared nanosilicon, we introduce and optimise a spraying method instead of using the usual casting technique for slurry application. Interestingly, the optimised electrodes show similar electrochemical performance, regardless of the particle size or composition of nanosilicon. This unexpected result is explained by the unusually high resistance of electrochemical wiring in silicon-based electrodes (about 60 Ohm per 1 mg cm-2 of active material loading). Despite that, the optimised material still shows a capacity up to 1200 mA h g-1 at a relatively high loading of 1.6 mg cm-2 and after 20 cycles. On the other hand, by decreasing the loading to below ca. 0.9 mg cm-2 the wiring problems are effectively overcome and capacities close to theoretical values can be obtained.

  9. Fractional Laser-Assisted Topical Imiquimod 5% Cream Treatment for Recalcitrant Common Warts in Children: A Pilot Study.

    Science.gov (United States)

    Park, Sung-Min; Kim, Gun-Wook; Mun, Je-Ho; Song, Margaret; Kim, Hoon-Soo; Kim, Byung-Soo; Kim, Moon-Bum; Ko, Hyun-Chang

    2016-12-01

    Conventional treatments for warts like cryotherapy are limited by the pain during procedures, especially in pediatric patients. Imiquimod is a topical immune response modifier, but the thick stratum corneum of common warts prevents drug permeation through skin. To evaluate the efficacy and safety of fractional laser/topical 5% imiquimod cream for the treatment of warts in children. Eleven pediatric patients with multiple recalcitrant common warts were included. Lesions were treated using an ablative fractional 2,940-nm Er:YAG laser at 1- or 2-week interval. After each laser treatment session, imiquimod 5% cream was self-applied once daily 5 days a week. Response and adverse effects were assessed 2 weekly until complete clearance or up to maximum of 48 weeks. Pain during fractional laser was assessed using a visual analogue scale (0-10). Eight of the 11 (72.7%) children experienced complete clearance. Mean duration was 29.7 (16-48) weeks, and the mean number of fractional laser was 17.5 (8-37). No significant adverse effect was observed. Pain visual analogue scale during fractional laser was 2.4 (1-4) compared to 6.2 (5-8) during cryotherapy. This pilot study indicates that fractional laser-assisted topical imiquimod may provide benefit for recalcitrant warts in children.

  10. Growth and modification of thin SiGeC films at low substrate temperatures through UV laser assisted processing

    Science.gov (United States)

    López, E.; Chiussi, S.; Serra, J.; González, P.; Serra, C.; Kosch, U.; León, B.; Fabbri, F.; Fornarini, L.; Martelli, S.

    2004-07-01

    Enhancing the performance of solar cells, near infrared photo-detectors and microelectronic devices through band gap engineering caused an increasing attention in processes for growing thin silicon germanium carbon (SiGeC) films in a wide range of composition and crystalline structures. Moreover, the demand of using cheap substrates and the development of new devices with advanced materials like "high- k dielectrics" and "organic materials" implies the need of new processes avoiding high substrate temperatures that may decompose or alter the substrate materials, crystallise part of the heterostructures or promote segregation effects. Laser induced chemical vapour deposition (LCVD) and excimer laser assisted crystallisation (ELC) are such alternative and relatively cheap "low thermal budget" techniques that, in addition, are compatible with conventional IC silicon technology. The present study will show the possibility of tailoring the composition of amorphous SiGeC coatings through the adjustment of gas flow rates in LCVD processes performed at substrate temperatures between 180 and 400 °C. The modification of an amorphous film through a subsequent ELC process performed at room temperature is analysed through SEM and depth profile XPS in order to study the effects of controlled laser radiation on it, as well as on a very thin underlaying interfacial SiO 2 layer and on the Si(1 0 0) substrate.

  11. Carbon-dioxide laser-assisted tonsil ablation for adults with chronic tonsillitis: a 6-month follow-up study.

    Science.gov (United States)

    Remacle, Marc; Keghian, Jerome; Lawson, Georges; Jamart, Jacques

    2003-09-01

    Sixty-six adult patients with a mean age of 44 years (range: 16-78) with chronic tonsillitis underwent laser-assisted tonsil ablation between January 1998 and January 2002. Instead of vaporization of the tonsil surface, extended serial tonsillectomy was performed, namely, vaporizing 80-90% of the palatine lymphoid tissue. Of the 66 patients, 49 (74%) underwent local anesthesia (LA group) and 17 (26%) general anesthesia (GA group). In the LA group, one surgical session sufficed for 40 patients (82%); two sessions were required for seven patients (14%) and three sessions for two patients (4%). Monopolar electrocautery was necessary to ensure hemostasis in two patients (3%). Median value results revealed a pain-intensity score of 4.5 (range: 0-10) for the GA group and 5 (range: 0-10) for the LA group. Pain lasted for 3 days (range: 0-15) in both groups (nonsignificant difference). A satisfaction score of 10 (range: 1-10) was recorded for the GA group and 8 (range: 1-10) for the LA group (P=0.029). The minimum follow-up was 6 months. Forty of the 49 LA group patients (82%) and 16 of the 17 GA group patients (94%) would recommend the surgical procedure and would accept undergoing the same operation again (nonsignificant difference).

  12. Effect of laser-assisted multi-point zona thinning on development and hatching of cleavage embryos in mice.

    Science.gov (United States)

    Lee, Young Seok; Park, Min Jung; Park, Sea Hee; Koo, Ja Seong; Moon, Hwa Sook; Joo, Bo Sun

    2015-06-01

    This study aimed to examine the effect of laser-assisted zona thinning (LAZT) at one or four-points on the blastocyst formation and hatching process in mice with respect to female age. Eight-cell or morula embryos collected from superovulated C57BL female mice with different ages (6-11 and 28-31 weeks) were treated with LAZT at one-point (LAZT1) or four-points (LAZT4). The zona pellucida was thinned to more than 70% of its initial thickness by making two holes of 15-20 µm. In the young mice, LAZT resulted in a significant increase in early hatching and hatching rates compared to the control group (p<0.05). However, in the old mice, LAZT significantly increased blastocyst formation as well as early hatching and hatching compared to the controls (p<0.05). These effects were more remarkable in LAZT4 than in LAZT1 and in aged mice than in young ones. These results show that multi-point LAZT leads to a significant improvement of blastocyst formation and hatching in mice compared to controls.

  13. Dislocation, fold and striae of corneal flap with laser assisted in situ keratomileusis after ocular trauma: a case report

    Institute of Scientific and Technical Information of China (English)

    Sang Yanzhi; Liu Xin; Zhong Ming; Zhao Chunyan

    2008-01-01

    Objective: To report the occurrence, management and outcome of late-onset traumatic dehiscence and islocation of laser assisted in situ keratomileusis (LASIK) flaps. Treatment and Results: One patient occurred ate-onset LASIK corneal flap dislocation after ocular trauma 7days after surgery. The flap was lifted, stretched, and epositioned after irrigation and scraping of the stromal bed and the underside of the flap. A bandage contact lens as placed, and topical antibiotic and corticosteroids were given postoperatively. The dislocated corneal flap was successfully repositioned in the case. The dislocated flap was repositioned 7 days after the trauma, and the patient recovered his uncorrected visual acuity (UCVA) of 10/20, 20/20 day 1 and day 20 after the procedure, of 20/20 20 days later and had a well-positioned flap with a clear interface. Diffuse lamellar keratitis developed in the patients hat resolved with the use of topical corticosteroids. Conclusion: Laser in situ keratomileusis corneal flaps are ulnerable to traumatic dehiscence and dislocation, which should be pay more attention to it for us.

  14. Tailored surface-enhanced Raman nanopillar arrays fabricated by laser-assisted replication for biomolecular detection using organic semiconductor lasers.

    Science.gov (United States)

    Liu, Xin; Lebedkin, Sergei; Besser, Heino; Pfleging, Wilhelm; Prinz, Stephan; Wissmann, Markus; Schwab, Patrick M; Nazarenko, Irina; Guttmann, Markus; Kappes, Manfred M; Lemmer, Uli

    2015-01-27

    Organic semiconductor distributed feedback (DFB) lasers are of interest as external or chip-integrated excitation sources in the visible spectral range for miniaturized Raman-on-chip biomolecular detection systems. However, the inherently limited excitation power of such lasers as well as oftentimes low analyte concentrations requires efficient Raman detection schemes. We present an approach using surface-enhanced Raman scattering (SERS) substrates, which has the potential to significantly improve the sensitivity of on-chip Raman detection systems. Instead of lithographically fabricated Au/Ag-coated periodic nanostructures on Si/SiO2 wafers, which can provide large SERS enhancements but are expensive and time-consuming to fabricate, we use low-cost and large-area SERS substrates made via laser-assisted nanoreplication. These substrates comprise gold-coated cyclic olefin copolymer (COC) nanopillar arrays, which show an estimated SERS enhancement factor of up to ∼ 10(7). The effect of the nanopillar diameter (60-260 nm) and interpillar spacing (10-190 nm) on the local electromagnetic field enhancement is studied by finite-difference-time-domain (FDTD) modeling. The favorable SERS detection capability of this setup is verified by using rhodamine 6G and adenosine as analytes and an organic semiconductor DFB laser with an emission wavelength of 631.4 nm as the external fiber-coupled excitation source.

  15. The study on force, surface integrity, tool life and chip on laser assisted machining of inconel 718 using Nd:YAG laser source.

    Science.gov (United States)

    Venkatesan, K

    2017-07-01

    Inconel 718, a high-temperature alloy, is a promising material for high-performance aerospace gas turbine engines components. However, the machining of the alloy is difficult owing to immense shear strength, rapid work hardening rate during turning, and less thermal conductivity. Hence, like ceramics and composites, the machining of this alloy is considered as difficult-to-turn materials. Laser assisted turning method has become a promising solution in recent years to lessen cutting stress when materials that are considered difficult-to-turn, such as Inconel 718 is employed. This study investigated the influence of input variables of laser assisted machining on the machinability aspect of the Inconel 718. The comparison of machining characteristics has been carried out to analyze the process benefits with the variation of laser machining variables. The laser assisted machining variables are cutting speeds of 60-150 m/min, feed rates of 0.05-0.125 mm/rev with a laser power between 1200 W and 1300 W. The various output characteristics such as force, roughness, tool life and geometrical characteristic of chip are investigated and compared with conventional machining without application of laser power. From experimental results, at a laser power of 1200 W, laser assisted turning outperforms conventional machining by 2.10 times lessening in cutting force, 46% reduction in surface roughness as well as 66% improvement in tool life when compared that of conventional machining. Compared to conventional machining, with the application of laser, the cutting speed of carbide tool has increased to a cutting condition of 150 m/min, 0.125 mm/rev. Microstructural analysis shows that no damage of the subsurface of the workpiece.

  16. The study on force, surface integrity, tool life and chip on laser assisted machining of inconel 718 using Nd:YAG laser source

    Directory of Open Access Journals (Sweden)

    K. Venkatesan

    2017-07-01

    Full Text Available Inconel 718, a high-temperature alloy, is a promising material for high-performance aerospace gas turbine engines components. However, the machining of the alloy is difficult owing to immense shear strength, rapid work hardening rate during turning, and less thermal conductivity. Hence, like ceramics and composites, the machining of this alloy is considered as difficult-to-turn materials. Laser assisted turning method has become a promising solution in recent years to lessen cutting stress when materials that are considered difficult-to-turn, such as Inconel 718 is employed. This study investigated the influence of input variables of laser assisted machining on the machinability aspect of the Inconel 718. The comparison of machining characteristics has been carried out to analyze the process benefits with the variation of laser machining variables. The laser assisted machining variables are cutting speeds of 60–150 m/min, feed rates of 0.05–0.125 mm/rev with a laser power between 1200 W and 1300 W. The various output characteristics such as force, roughness, tool life and geometrical characteristic of chip are investigated and compared with conventional machining without application of laser power. From experimental results, at a laser power of 1200 W, laser assisted turning outperforms conventional machining by 2.10 times lessening in cutting force, 46% reduction in surface roughness as well as 66% improvement in tool life when compared that of conventional machining. Compared to conventional machining, with the application of laser, the cutting speed of carbide tool has increased to a cutting condition of 150 m/min, 0.125 mm/rev. Microstructural analysis shows that no damage of the subsurface of the workpiece.

  17. Irregularity of the posterior corneal surface during applanation using a curved femtosecond laser interface and microkeratome cutting head.

    Science.gov (United States)

    Vetter, Jan M; Holtz, Carsten; Vossmerbaeumer, Urs; Pfeiffer, Norbert

    2012-03-01

    To evaluate the irregularity of the posterior corneal surface and intrastromal dissection during the preparation of donor tissue for Descemet stripping automated endothelial keratoplasty (DSAEK) using a curved interface femtosecond laser and microkeratome. Sixteen human donor corneas unsuitable for transplantation were divided into two groups: a femtosecond (FS) laser group (n=7) using the VisuMax femtosecond laser (Carl Zeiss Meditec) and a microkeratome group (n=9) using the Amadeus II microkeratome (Ziemer Ophthalmic Group). The corneas were fixed on artificial anterior chambers. Horizontal cross-sections were obtained using spectral-domain optical coherence tomography prior to applanation, during applanation, as well as during and after intrastromal dissection at 450-μm corneal depth. The posterior surface and the dissection line were evaluated for irregularity by fitting a second-order polynomial curve using regression analysis and obtaining the root-mean-square error (RMSE). Groups were compared using analysis of variance. The RMSE of the posterior surface prior to applanation was 9.7 ± 3.1 μm in the FS laser group and 10.2 ± 2.3 μm in the microkeratome group. The RMSE increased to 50.7 ± 9.4 μm and 20.9 ± 6.1 μm during applanation and decreased again to 10.6 ± 1.4 μm and 8.1 ± 1.8 μm after applanation in the FS laser and microkeratome groups, respectively. The RMSE of the intrastromal cut was 19.5 ± 5.7 μm in the FS laser group and 7.7 ± 3.0 μm in the microkeratome group (Plaser-assisted cleavage compared to microkeratome-assisted corneal dissection, possibly due to applanation-derived deformation of the posterior cornea. Copyright 2012, SLACK Incorporated.

  18. Femtosecond laser cutting of multiple thin corneal stromal lamellae for endothelial bioengineering.

    Science.gov (United States)

    Bernard, Aurélien; He, Zhiguo; Forest, Fabien; Gauthier, Anne-Sophie; Peocʼh, Michel; Dumollard, Jean-Marc; Acquart, Sophie; Montard, Romain; Delbosc, Bernard; Gain, Philippe; Thuret, Gilles

    2015-02-01

    To assess the feasibility of cutting multiple thin stromal lamellae in human donor corneas using a commercial femtosecond laser (FSL) to provide cell carriers for future endothelial graft bioengineering. Eight edematous organ-cultured corneas not suitable for grafting for endothelial reasons were mounted on a Ziemer anterior chamber and cut with a Z6 FSL with 6 successive parallel cuts, from depth to surface. Target thickness of each lamella ranged from 100 to 150 μm depending on initial corneal thickness. Thickness was measured using anterior segment optical coherence tomography before and after cutting on mounted corneas, and on each stromal lamella after detachment. Scanning electron microscopy observation was performed on 4 lamellae and histological cross sections on 1 cornea before detachment. A median of 5 (minimum 3, maximum 7) lamellae was obtained per cornea. All lamellae still attached were the most posterior ones, suggesting that FSL was less efficient because of light scattering by edematous stroma. Cut precision and postdetachment swelling were correlated with anterior-posterior position within the cornea. Median lamella thickness was 127 μm (56-222 μm) before detachment and 196 μm (80-304 μm) after detachment. Surface state was consistent with previously reported FSL lamellar cuts during Descemet stripping automated endothelial keratoplasty. Up to 7 thin lamellae can be cut in stored corneas with an FSL. This method, once optimized primarily by using deswelled, more transparent corneas, could prove effective for recycling unsuitable donor corneas in corneal bioengineering processes.

  19. Effect of Topical FK506 Used alone or Combined with Keratoplasty on Patients with Recurrent Mooren's Corneal Ulcer

    Institute of Scientific and Technical Information of China (English)

    Hanping Xie; Jiaqi Chen; Yueshen Lin; Yongming Liu; Chentian Ye; Shiyou Zhou

    2006-01-01

    Purpose: To evaluate the efficacy of topical 0.1% FK506 used alone or combined with keratoplasty on patients with recurrent Mooren's ulcer.Methods: This is a retrospective interventional consecutive case series. Nine patients(15 eyes) with recurrent Mooren's ulcer were treated with topical 0.1% FK506 alone or combined with keratoplasty. Two eyes with ulcers involving less than half the corneal limbus were treated with topical 0.1% FK506. Of the other 13 eyes with ulcers involving more than half the limbus, twelve were treated with excision of the ulcer and adjacent conjunctiva combined with lamellar keratoplasty. One eye with a central impending corneal perforation was treated with penetrating keratoplasty.Topical0.1% FK506 was given post-operatively to all thirteen eyes after re-epithelia-lisation of the cornea. FK506 levels in the surgically resected cornea and conjunctiva of the operated eyes were measured using enzyme immunoassay procedures. Twelve patients(17 eyes) with recurrent Mooren's ulcer treated with lamellar keratoplasty combined with topical 0.1% dexamethasone were taken as the control. The main measure of the outcome was the recurrence of Mooren's ulcer in the patients.Results: Nine patients (15 eyes) with recurrent Mooren's ulcer were all successfully treated. Vision in 5 eyes improved by two lines or better after treatment. No recurrence was observed during the follow up period of 12 to 22 months. After topical application of 0.1% FK506, concentrations of 30~350 ng/g of FK506 were found in the cornea and conjunctiva. Seven eyes of Mooren's ulcer in the control group recurred during the follow up period. Conclusion: Topical 0.1% FK506 used alone or combined with keratoplasty is a safe and effective therapy for patients with recurrent Mooren's ulcer.

  20. A Technique to Salvage Big-Bubble Deep Anterior Lamellar Keratoplasty after Inadvertent Full-Thickness Trephination

    OpenAIRE

    Siamak Zarei-Ghanavati1; Mehran Zarei-Ghanavati

    2011-01-01

    Herein we describe a technique for management of large inadvertent full-thickness trephination during deep anterior lamellar keratoplasty using the big-bubble technique without converting to penetrating keratoplasty. First, the anterior chamber is formed with an ophthalmic viscosurgical device (OVD). Then, the full-thickness wound is secured with one X-type 10-0 nylon suture. A 27-gauge needle is attached to a 2 ml air-filled syringe and inserted into the corneal stroma in the meridian opposi...

  1. Isotope dilution ICP-MS with laser-assisted sample introduction for direct determination of sulfur in petroleum products.

    Science.gov (United States)

    Boulyga, Sergei F; Heilmann, Jens; Heumann, Klaus G

    2005-08-01

    Inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with direct laser-assisted introduction of isotope-diluted samples into the plasma, using a laser ablation system with high ablation rates, was developed for accurate sulfur determinations in different petroleum products such as 'sulfur-free' premium gasoline, diesel fuel, and heating oil. Two certified gas oil reference materials were analyzed for method validation. Two different 34S-enriched spike compounds, namely, elementary sulfur dissolved in xylene and dibenzothiophene in hexane, were synthesized and tested for their usefulness in this isotope dilution technique. The isotope-diluted sample was adsorbed on a filter-paper-like material, which was fixed in a special holder for irradiation by the laser beam. Under these conditions no time-dependent spike/analyte fractionation was only observed for the dibenzothiophene spike during the laser ablation process, which means that the measured 34S/32S isotope ratio of the isotope-diluted sample remained constant-a necessary precondition for accurate results with the isotope dilution technique. A comparison of LA-ICP-IDMS results with the certified values of the gas oil reference materials and with results obtained from ICP-IDMS analyses with wet sample digestion demonstrated the accuracy of the new LA-ICP-IDMS method in the concentration range of 9.2 microg g(-1) ('sulfur-free' premium gasoline) to 10.4 mg g(-1) (gas oil reference material BCR 107). The detection limit for sulfur by LA-ICP-IDMS is 0.04 microg g(-1) and the analysis time is only about 10 min, which therefore also qualifies this method for accurate determinations of low sulfur contents in petroleum products on a routine level.

  2. Isotope dilution ICP-MS with laser-assisted sample introduction for direct determination of sulfur in petroleum products

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, Sergei F.; Heilmann, Jens; Heumann, Klaus G. [Johannes Gutenberg-University Mainz (Germany). Institute of Inorganic Chemistry and Analytical Chemistry

    2005-08-01

    Inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with direct laser-assisted introduction of isotope-diluted samples into the plasma, using a laser ablation system with high ablation rates, was developed for accurate sulfur determinations in different petroleum products such as 'sulfur-free' premium gasoline, diesel fuel, and heating oil. Two certified gas oil reference materials were analyzed for method validation. Two different {sup 34}S-enriched spike compounds, namely, elementary sulfur dissolved in xylene and dibenzothiophene in hexane, were synthesized and tested for their usefulness in this isotope dilution technique. The isotope-diluted sample was adsorbed on a filter-paper-like material, which was fixed in a special holder for irradiation by the laser beam. Under these conditions no time-dependent spike/analyte fractionation was only observed for the dibenzothiophene spike during the laser ablation process, which means that the measured {sup 34}S/{sup 32}S isotope ratio of the isotope-diluted sample remained constant - a necessary precondition for accurate results with the isotope dilution technique. A comparison of LA-ICP-IDMS results with the certified values of the gas oil reference materials and with results obtained from ICP-IDMS analyses with wet sample digestion demonstrated the accuracy of the new LA-ICP-IDMS method in the concentration range of 9.2 {mu}g g{sup -1} ('sulfur-free' premium gasoline) to 10.4 mg g{sup -1} (gas oil reference material BCR 107). The detection limit for sulfur by LA-ICP-IDMS is 0.04 {mu}g g{sup -1} and the analysis time is only about 10 min, which therefore also qualifies this method for accurate determinations of low sulfur contents in petroleum products on a routine level. (orig.)

  3. Spray- and laser-assisted biomaterial processing for fast and efficient autologous cell-plus-matrix tissue engineering.

    Science.gov (United States)

    Klopsch, Christian; Gäbel, Ralf; Kaminski, Alexander; Mark, Peter; Wang, Weiwei; Toelk, Anita; Delyagina, Evgenya; Kleiner, Gabriela; Koch, Lothar; Chichkov, Boris; Mela, Petra; Jockenhoevel, Stefan; Ma, Nan; Steinhoff, Gustav

    2015-12-01

    At present, intensive investigation aims at the creation of optimal valvular prostheses. We introduced and tested the applicability and functionality of two advanced cell-plus-matrix seeding technologies, spray-assisted bioprocessing (SaBP) and laser-assisted bioprocessing (LaBP), for autologous tissue engineering (TE) of bioresorbable artificial grafts. For SaBP, human mesenchymal stem cells (HMSCs), umbilical cord vein endothelial cells (HUVECs) and fibrin were simultaneously spray-administered on poly(ε-caprolactone) (PCL) substrates. For LaBP, HUVECs and HMSCs were separately laser-printed in stripes, followed by fibrin sealing. Three-leaflet valves were manufactured following TE of electrospun PCL tissue equivalents. Grafts were monitored in vitro under static and dynamic conditions in bioreactors. SaBP and LaBP resulted in TE of grafts with homogeneous cell distribution and accurate cell pattern, respectively. The engineered valves demonstrated immediate sufficient performance, complete cell coating, proliferation, engraftment, HUVEC-mediated invasion, HMSC differentiation and extracellular matrix deposition. SaBP revealed higher efficiency, with at least 12-fold shorter processing time than the applied LaBP set-up. LaBP realized coating with higher cell density and minimal cell-scaffold distance. Fibrin and PCL stability remain issues for improvement. The introduced TE technologies resulted in complete valvular cell-plus-matrix coating, excellent engraftment and HMSCs differentiation. SaBP might have potential for intraoperative table-side TE considering the procedural duration and ease of implementation. LaBP might accelerate engraftment with precise patterns.

  4. A powerful method for transcriptional profiling of specific cell types in eukaryotes: laser-assisted microdissection and RNA sequencing.

    Directory of Open Access Journals (Sweden)

    Marc W Schmid

    Full Text Available The acquisition of distinct cell fates is central to the development of multicellular organisms and is largely mediated by gene expression patterns specific to individual cells and tissues. A spatially and temporally resolved analysis of gene expression facilitates the elucidation of transcriptional networks linked to cellular identity and function. We present an approach that allows cell type-specific transcriptional profiling of distinct target cells, which are rare and difficult to access, with unprecedented sensitivity and resolution. We combined laser-assisted microdissection (LAM, linear amplification starting from <1 ng of total RNA, and RNA-sequencing (RNA-Seq. As a model we used the central cell of the Arabidopsis thaliana female gametophyte, one of the female gametes harbored in the reproductive organs of the flower. We estimated the number of expressed genes to be more than twice the number reported previously in a study using LAM and ATH1 microarrays, and identified several classes of genes that were systematically underrepresented in the transcriptome measured with the ATH1 microarray. Among them are many genes that are likely to be important for developmental processes and specific cellular functions. In addition, we identified several intergenic regions, which are likely to be transcribed, and describe a considerable fraction of reads mapping to introns and regions flanking annotated loci, which may represent alternative transcript isoforms. Finally, we performed a de novo assembly of the transcriptome and show that the method is suitable for studying individual cell types of organisms lacking reference sequence information, demonstrating that this approach can be applied to most eukaryotic organisms.

  5. Characterization of diamond thin films deposited by a CO{sub 2} laser-assisted combustion-flame method

    Energy Technology Data Exchange (ETDEWEB)

    McKindra, Travis, E-mail: mckindra@mst.edu [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); O' Keefe, Matthew J. [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Xie Zhiqiang; Lu Yongfeng [Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States)

    2010-06-15

    Diamond thin films were deposited by a CO{sub 2} laser-assisted O{sub 2}/C{sub 2}H{sub 2}/C{sub 2}H{sub 4} combustion-flame process. The effect of the deposition parameters, in particular the laser wavelength and power, on the film surface morphology, microstructure and phases present was the primary focus of the work. The laser power was set at 100, 400 and 800 W while the wavelength was varied and set at 10.591 {mu}m in the untuned condition and set at 10.532 {mu}m to resonantly match the CH{sub 2}-wagging vibrational mode of the C{sub 2}H{sub 4} molecule when in the tuned condition. When the laser was coupled to the combustion flame during deposition the diamond film growth was enhanced as the lateral grain size increased from 1 {mu}m to greater than 5 {mu}m. The greatest increase in grain size occurred when the wavelength was in the tuned condition. Scanning transmission electron microscopy images from focused-ion beam cross-sectioned samples revealed a sub-layer of smaller grains less than 1 {mu}m in size near the substrate surface at the lower laser powers and untuned wavelength. X-ray diffraction results showed a more intense Diamond (111) peak as the laser power increased from 100 to 800 W for the films deposited with the tuned laser wavelength. Micro-Raman spectra showed a diamond peak nearly twice as intense from the films with the tuned laser wavelength.

  6. First experience with the new high-frequency femtosecond laser system (LDV Z8 for cataract surgery

    Directory of Open Access Journals (Sweden)

    Pajic B

    2014-12-01

    Full Text Available Bojan Pajic,1–3 Iraklis Vastardis,1,2 Zisis Gatzioufas,1 Brigitte Pajic-Eggspuehler1 1Swiss Eye Research Foundation, Eye Clinic ORASIS, Reinach, Switzerland; 2Eye Hospital VIDAR-ORASIS Swiss, Department of Physics, Faculty of Sciences, University of Novi Sad, Novi Sad, Serbia; 3Medical Faculty, Military Medical Academy, University of Defense, Belgrade, Serbia Background: The purpose of this work is to report our experience using the new Z8 laser system for femtosecond laser-assisted cataract surgery (FLACS and to provide a sample of the performance and safety results using this new technology. Methods: This prospective observational study was performed at the Swiss Eye Research Foundation, Eye Clinic ORASIS, Reinach, Switzerland. Fourteen patients were subjected to unilateral FLACS. Capsulotomy and lens fragmentation were performed with the aid of the LDV Z8 femtosecond laser system. Ease of phacoemulsification (on a 4-point scale, completeness of capsulotomy (on a 10-point scale, time for preparation of femtosecond laser (minutes, effective phacoemulsification time (seconds, total duration of surgery (minutes, and safety of the procedure were evaluated. Results: Ease of fragmentation and completeness of capsulotomy were estimated at 3.9 and 9.9, respectively. The preparation time for femtosecond was 3.6±0.7 minutes, effective phacoemulsification time was 2.5±3.1 seconds, and total duration of the FLACS procedure was 16.3±4.5 minutes. No major complications were observed. Approximately 42% of all patients (6/14 showed Descemet’s folds directly postoperatively. Conclusion: FLACS with the LDV Z8 system was characterized by complete capsulotomy and highly effective and reproducible lens fragmentation. The safety of the procedure was very good as perceived by the surgeon operating in this observational case series. The cost to benefit ratio should be further debated by assessing the results of a major prospective study, which is required for

  7. Comparison the post operative refractive errors in same size corneal transplantation through deep lamellar keratoplasty and penetrating keratoplasty methods after sutures removing in keratoconus patients

    Directory of Open Access Journals (Sweden)

    Hasan Razmjoo

    2016-01-01

    Full Text Available Background: Corneal transplantation is a surgery in which cornea is replaced by a donated one and can be completely penetrating keratoplasty (PK or included a part of cornea deep lamellar keratoplasty (DLK. Although the functional results are limited by some complications, it is considered as one of the most successful surgeries. This study aimed to compare the refractive errors after same size corneal transplantation through DLK and PK methods in keratoconus patients over 20 years. Materials and Methods: This descriptive, analytical study was conducted in Feiz Hospital, Sadra and Persian Clinics of Isfahan in 2013–2014. In this study, 35 patients underwent corneal transplantation by PK and 35 patients by DLK, after removing the sutures, the patients were compared in terms of best corrected visual acuity (BCVA and refractive errors. Data were analyzed using Chi-square and t Student tests by SPSS software. Results: The BCVA mean in DLK and PK groups was 6/10 ± 2/10 and 5/10 ± 2/10, respectively, with no significant difference (P = 0.4. The results showed 9 cases of DLK and 6 cases of PK had normal (8/10 ≤ BCVA visual acuity (25.7% vs. 17.1%, 24 cases of DLK and 27 cases of PK had mild vision impairment (68.6% vs. 77.1% and 2 cases of the DLK group and 2 cases of PK had moderate vision impairment, (5.7% vs. 5.7%, there was no significant difference in “BCVA” (P = 0.83. Conclusions: Both methods were acceptably effective in improving BCVA, but according to previous articles (5,9,10 the DLK method due to fewer complications and less risk of rejection was superior to another method and in the absence of any prohibition this method is recommended.

  8. [Corneal wound healing after experimental penetrating keratoplasty after excimer laser trephination in free form].

    Science.gov (United States)

    Schmitz, K; Lang, G K; Behrens-Baumann, W

    2006-12-01

    The postoperative clinical course after penetrating keratoplasty and trephination in free form using a guided excimer laser beam has been published before. Here the findings of light-microscopy comparing corneal wound healing after experimental penetrating keratoplasty after laser trephination and after conventional mechanical trephination are presented. Homologous penetrating keratoplasty was performed on 12 NZW rabbits (6 animals with mechanical trephination, 6 animals with excimer laser trephination). The cutting edges achieved by both trephination techniques were examined by light microscopy in the remaining donor rings. During the postoperative follow-up animals were sacrificed at 3 and 6 weeks and at 3 months. Corneal specimens were retrieved and corneal healing processes were evaluated by light microscopy. The cutting edges of corneal excisions with the excimer laser demonstrated a high precision with only minimal collateral damage to adjacent tissue structures. At the different intervals both trephination groups demonstrated comparable stages of corneal wound healing regarding epithelial regeneration, stromal fibroblast migration with collagen synthesis and Descemet repair by endothelial synthesis of basement membrane. After 6 months corneal specimens of both groups demonstrated complete healing with nearly parallel orientation of newly synthesised collagen lamellae. Corneal thickness in the wound areas did not differ significantly from normal corneal tissue. Experimental follow-up studies to evaluate the feasibility of the developed technology of laser trephination in the living eye have shown no differences between conventional mechanical and excimer laser trephination with a guided beam. The present histology study also does not demonstrate any significant differences in corneal wound healing between the two trephination groups. Although excimer laser trephination along metal masks has now been established for several years, the here presented technique

  9. Outcomes of Descemet Stripping Endothelial Keratoplasty Using Eye Bank-Prepared Preloaded Grafts.

    Science.gov (United States)

    Palioura, Sotiria; Colby, Kathryn

    2017-01-01

    To evaluate the feasibility of Descemet stripping endothelial keratoplasty using grafts preloaded by an eye bank in a commercially available insertion device. In this retrospective case series, a series of 35 eyes in 34 consecutive patients who underwent Descemet stripping endothelial keratoplasty for Fuchs endothelial dystrophy or previously failed full-thickness grafts at a single tertiary care center from March 2013 to March 2014 was included. The donor tissue had undergone pre-lamellar dissection, trephination, and loading into EndoGlide Ultrathin inserters at the Lions Eye Institute for Transplant and Research (Tampa, FL) and was shipped overnight in Optisol GS to the surgeon (K.C.). Surgery was performed within 24 hours from tissue preparation and loading by the eye bank. Donor and recipient characteristics, endothelial cell density (ECD), best-corrected visual acuity, and central corneal thickness were recorded. The main outcome measures were intraoperative and postoperative complications and ECD loss at 3, 6, and 12 months. One primary graft failure (2.8%), 2 rebubblings (5.7%), and 1 graft rejection (2.8%) occurred. Mean preoperative donor ECD was 2821 ± 199 cells/mm. Six months postoperatively, the mean endothelial cell loss was 25.3% ± 17.2% (n = 32), which remained stable at 1 year (31.5% ± 17.9%, n = 32). Mean best-corrected visual acuity improved from 20/100 preoperatively to 20/25 at a mean follow-up of 1 year (n = 32). Mean central corneal thickness was reduced from 711 ± 110 μm to 638 ± 66 μm at the last follow-up visit. Donor graft tissue preloaded by an eye bank can be used successfully for endothelial keratoplasty. Preloading reduces intraoperative tissue manipulation.

  10. Retained nuclear fragment found during Descemet-stripping automated endothelial keratoplasty.

    Science.gov (United States)

    Mifflin, Mark D; Neuffer, Marcus C; Mamalis, Nick

    2011-03-01

    An 82-year-old man with a 2- to 3-month history of progressive visual loss due to corneal edema was referred to our center. The ocular history was significant for uneventful cataract surgery approximately 3 years earlier. Pseudophakic bullous keratopathy was diagnosed and Descemet-stripping automated endothelial keratoplasty (DSAEK) performed. During surgery, a retained nuclear fragment was discovered in the anterior chamber. The fragment was removed and the DSAEK completed successfully. At the 4-month follow-up, the symptoms had completely resolved and the uncorrected distance visual acuity in the affected eye was 20/40. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  11. In vivo confocal microscopy in recurrent granular dystrophy in corneal graft after penetrating keratoplasty.

    Science.gov (United States)

    Traversi, Claudio; Martone, Gianluca; Malandrini, Alex; Tosi, Gian Marco; Caporossi, Aldo

    2006-11-01

    Two case reports of recurrent granular dystrophy in corneal grafts after penetrating keratoplasty are presented. Slit-lamp examination and confocal microscopy (HRT II) were performed in two patients with recurrent granular dystrophy. All confocal microscopic findings of granular dystrophy were evaluated in the graft. Dystrophic lesions of the donor cornea presented the same confocal microscopic aspects in both eyes, and were similar to granular dystrophy lesions. Confocal microscopy is an imaging method that may provide new information on corneal microanatomy in dystrophies. It may be particularly useful in improving the early diagnosis of dystrophic lesions in corneal grafts.

  12. Differentiating type 1 from type 2 big bubbles in deep anterior lamellar keratoplasty

    Directory of Open Access Journals (Sweden)

    Dua HS

    2015-06-01

    Full Text Available Harminder S Dua,1 Tarek Katamish,2 Dalia G Said,1 Lana A Faraj1 1Section of Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK; 2Department of Ophthalmology, Cairo University, Cairo, EgyptWe read with interest the paper by Anwar et al.1 The authors have described a technique to bare Descemet’s membrane (DM by multiple lamellar dissection of the deep corneal stroma when stromal injection of air fails to achieve a big bubble (BB in deep anterior lamellar keratoplasty (DALK.Read the original article

  13. Towards sub-femtosecond emission

    Science.gov (United States)

    Bach, Roger; Hansen, Peter; Batelaan, Herman; Hilbert, Shawn

    2010-03-01

    To manipulate femtosecond pulses of electrons new electron optical elements are needed. For example, if a source has a lower limit in the duration of the electron pulses that it generates, then aan electron optical element that can reduce the pulse duration could be useful. An example of this is the proposed ``temporal lens '' [1]. To detect the short electron pulses one also needs new elements. Attempts to use the ponderomotive interaction between the electron pulse and a second laser pulse will be presented [2]. Alternatively, we have started to explore a plasmonics structure provided by the Capasso group to make a fast electron switch. This has the potential to be useful both for switching, shaping and detecting the electron pulse. Finally, the experimental parameters and detection ideas for quantum degeneracy will be discussed. [1] S. Hilbert, B. Barwick, K. Uiterwaal, H. Batelaan, A. Zewail, ``Temporal lenses for attosecond and femtosecond electron pulses'', Proceedings of the National Academy of Sciences, p. 10558, vol. 106, (2009). [2] L. Kreminskaya, C. Corder, V. Engquist, O. Golovin, P. Hansen, H. Batelaan, A. I. Khizhnyak, G. A. Swartzlander, Jr., ``Laser Beam Shaping: Donut Mode Formation by Interference.'' Laser Beam Shaping X (Proceedings Volume) Proceedings of SPIE Volume: 7430.

  14. Laser-Assisted Operculectomy.

    Science.gov (United States)

    Levine, Robert; Vitruk, Peter

    2015-09-01

    The 10,600-nm CO2 laser is both an efficient and spatially precise photo-thermal ablation device and excellent coagulator because of the close match between its coagulation depth and the diameters of oral soft-tissue capillaries. The ablation of hyperplastic oral soft tissue with the flexible fiber waveguide 10,600-nm CO2 laser is a minimally invasive and typically suture-free surgical modality that ensures dependable treatment. It is, in many respects, superior to most of the alternative treatment options. Its excellent hemostatic abilities and the minimal damage to adjacent healthy tissues make the CO2 laser a perfect surgical tool for treating oral soft-tissue lesions, including the inflamed operculum.

  15. Influence of multi-hit capability on quantitative measurement of NiPtSi thin film with laser-assisted atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kinno, T., E-mail: teruyuki.kinno@toshiba.co.jp [Corporate Research and Development Center, Toshiba Corporation, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8522 (Japan); Akutsu, H.; Tomita, M. [Corporate Research and Development Center, Toshiba Corporation, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8522 (Japan); Kawanaka, S. [Center for Semiconductor Research and Development, Toshiba Corporation Semiconductor and Storage Products Company, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8522 (Japan); Sonehara, T. [Advanced Memory Development Center, Toshiba Corporation Semiconductor and Storage Products Company, 800 Yamano-Isshiki-cho, Yokkaichi, Mie 512-8550 (Japan); Hokazono, A. [Center for Semiconductor Research and Development, Toshiba Corporation Semiconductor and Storage Products Company, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8522 (Japan); Renaud, L.; Martin, I.; Benbalagh, R.; Salle, B. [Cameca SAS, 29 Quai des Gresillons, 92622 Gennevilliers Cedex (France); Takeno, S. [Corporate Research and Development Center, Toshiba Corporation, 8 Shinsugita-cho, Isogo-ku, Yokohama 235-8522 (Japan)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Laser-assisted atom probe tomography was applied to NiPtSi films on Si substrates. Black-Right-Pointing-Pointer Comparison of depth profiles of single-hit events and those of multi-hit events. Black-Right-Pointing-Pointer {approx}80% of Pt atoms were detected in multi-hit events. Black-Right-Pointing-Pointer Multiple-ion detection is important for Laser-assisted atom probe tomography. - Abstract: Laser-assisted atom probe tomography (LA-APT) was applied to NiPtSi (0, 30, and 50% Pt contents) thin films on Si substrates. Consistent results with those of high-resolution Rutherford backscattering spectrometry (HR-RBS) were obtained. Based on the obtained data sets, the composition profiles from only the signals of single-hit events, meaning detection of one ion by one laser pulse, were compiled. The profiles from only the signals of multi-hit events, meaning detection of multiple ions by one laser pulse, were also compiled. There were large discrepancies with respect to Ni and Pt concentrations among the compiled profiles and the original profiles including the signals of both types of detection events. Additionally, the profiles compiled from single-hit events showed that Si concentration in NiPtSi layer became smaller toward the surface, differing from the original profiles and the multi-hit profiles. These results suggest that capability of simultaneous multiple-ion detection is important for appropriate LA-APT analyses.

  16. Free lymph node flap transfer and laser-assisted liposuction: a combined technique for the treatment of moderate upper limb lymphedema.

    Science.gov (United States)

    Nicoli, Fabio; Constantinides, Joannis; Ciudad, Pedro; Sapountzis, Stamatis; Kiranantawat, Kidakorn; Lazzeri, Davide; Lim, Seong Yoon; Nicoli, Marzia; Chen, Pei-Yu; Yeo, Matthew Sze-Wei; Chilgar, Ram M; Chen, Hung-Chi

    2015-05-01

    Upper limb lymphedema following breast cancer surgery is a challenging problem for the surgeon. Lymphatico-venous or lymphatico-lymphatic anastomoses have been used to restore the continuity of the lymphatic system, offering a degree of improvement. Long-term review indicates that lumen obliteration and occlusion at the anastomosis level commonly occurs with time as a result of elevated venous pressure. Lymph node flap transfer is another microsurgical procedure designed to restore lymphatic system physiology but does not provide a complete volume reduction, particularly in the presence of hypertrophied adipose tissue and fibrosis, common in moderate and advanced lymphedema. Laser-assisted liposuction has been shown to effectively reduce fat and fibrotic tissues. We present preliminary results of our practice using a combination of lymph node flap transfer and laser-assisted liposuction. Between October 2012 and May 2013, ten patients (mean 54.6 ± 9.3 years) with moderate (stage II) upper extremity lymphedema underwent groin or supraclavicular lymph node flap transfer combined with laser-assisted liposuction (high-power diode pulsed laser with 1470-nm wavelength, LASEmaR 1500-EUFOTON, Trieste, Italy). A significant decrease of upper limb circumference measurements at all levels was noted postoperatively. Skin tonicity was improved in all patients. Postoperative lymphoscintigraphy revealed reduced lymph stasis. No patient suffered from donor site morbidity. Our results suggest that combining laser liposuction with lymph node flap transfer is a safe and reliable procedure, achieving a reduction of upper limb volume in treated patients suffering from moderate upper extremity lymphedema.

  17. Non-Descemet’s stripping automated endothelial keratoplasty for bullous keratopathy secondary to iridoschisis

    Directory of Open Access Journals (Sweden)

    Minezaki T

    2013-07-01

    Full Text Available Teruumi Minezaki, Takaaki Hattori, Hayate Nakagawa, Shigeto Kumakura, Hiroshi GotoDepartment of Ophthalmology, Tokyo Medical University, Shinjukuku, Tokyo, JapanPurpose: To report a case of bullous keratopathy secondary to iridoschisis treated by non-Descemet's stripping automated endothelial keratoplasty (nDSAEK.Case report: A 79-year-old woman was referred to our hospital with loss of vision in the left eye. Slit lamp examination of her left eye showed a shallow anterior chamber with cataract and schisis in the inferior quadrant of iris stroma. Bullous keratopathy secondary to iridoschisis was diagnosed. Cataract surgery with iridectomy succeeded to deepen the anterior chamber and remove the floating iris leaf, although corneal edema remained. Four days later, nDSAEK was performed, which resolved corneal edema and restored visual acuity.Conclusion: The two-step surgery of cataract surgery plus iridectomy followed by nDSAEK may be an effective strategy for treating bullous keratopathy secondary to iridoschisis.Keywords: iridoschisis, bullous keratopathy, non-Descemet's stripping automated endothelial keratoplasty

  18. Hydrophilic Acrylic Intraocular Lens Opacification after Descemet Stripping Automated Endothelial Keratoplasty

    Science.gov (United States)

    Norouzpour, Amir; Zarei-Ghanavati, Siamak

    2016-01-01

    Purpose: To report hydrophilic acylic intraocular lens (IOL) opacification after Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) in an eye with multiple prior intraocular surgeries and iatrogenic aniridia. Case Report: A 34-year-old woman with history of penetrating keratoplasty (PKP) for advanced keratoconus and subsequent Urrets-Zavalia Syndrome (UZS) underwent phacoemulsification and hydrophilic acrylic IOL implantation for her cataract. In order to control post-PKP glaucoma, multiple glaucoma surgeries including two glaucoma drainage implants were performed. As the original corneal graft failed, the patient subsequently underwent re-PKP. Four years later, she underwent DSAEK for treatment of the second graft failure. Ten months after DSAEK, a double semi-circular pattern of IOL opacification was observed on the anterior surface of the IOL. The patient did not report any complaints and we decided not to exchange the IOL. Conclusion: In an eye with UZS and iatrogenic aniridia, IOL opacification may result from direct contact between the IOL surface and exogenous air. Aniridia can be a risk factor for development of IOL opacification after DSAEK. Further studies are required to confirm this hypothesis. PMID:27413506

  19. Descemet-stripping automated endothelial keratoplasty for vitrectomized cases with traumatic aniridia and aphakic bullous keratopathy

    Directory of Open Access Journals (Sweden)

    Eguchi H

    2012-09-01

    Full Text Available Hiroshi Eguchi, Tatsuro Miyamoto, Fumika Hotta, Machiko Tomida, Masayuki Inoue, Yoshinori MitamuraDepartment of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, JapanAbstract: The surgical indication for Descemet-stripping automated endothelial keratoplasty (DSAEK is largely limited to phakic or pseudophakic cases of endothelial dysfunction with normal pupils, because the endothelial lenticule is generally attached to the recipient cornea by use of gas tamponade into the anterior chamber. Although it may be desirable for vitrectomized cases with aniridia and aphakic bullous keratopathy without capsule support to undergo DSAEK, one of the major problems is lenticule detachment during surgery or in the postoperative period. To perform DSAEK in such cases, special surgical techniques are needed in order to facilitate adhesion of the lenticule. Herein, we describe a suture technique for attaching the endothelial lenticule in DSAEK for aniridic and aphakic cases that have undergone vitrectomy for traumatic vitreoretinal disease.Keywords: traumatic aniridia, aphakic bullous keratopathy, Descemet-stripping automated endothelial keratoplasty, vitrectomy

  20. Endothelial keratoplasty for corneal decompensation leaded by a dexamethasone implant dislocation in anterior chamber

    Directory of Open Access Journals (Sweden)

    Fernanda Pacella

    2016-06-01

    Full Text Available Background: Dexamethasone intravitreal implant (DEX largely showed his safety and efficacy for the treatment of cases of macular edema. Even if uncommon, delivery dislocation in anterior chamber has been described in Literaure as complication of the injection procedure, leading to irreversible endothelial cell loss in the majority of cases. We report a case of a 66-year-old man with pain and vision loss in his left eye. The anamnesis revealed a recent intravitreal injection of DEX implant for a persistent cystoid macular edema related to central retinal vein occlusion. Anterior segment examination showed corneal edema and the rod implant adherent to corneal endothelium. A large peripheral iridectomy was evident with retroillumination and IOL appeared good centered in the bag. The implant was removed but corneal decompensation was irreversible. One month later, an endothelial keratoplasty was successfully performed restoring corneal transparency. DEX intravitreal implant can migrate from vitreous cavity to anterior chamber and lead to irreversible corneal decompensation by mechanical and chemical toxicity on corneal endothelium. Removeal of the implant is necessary to avoid total endothelial decompensation. Despite this, in some cases endothelial keratoplasty had to be performed.

  1. The complementary benefit of anterior segment optical coherence tomography in penetrating keratoplasty

    Directory of Open Access Journals (Sweden)

    Yenerel NM

    2013-07-01

    Full Text Available Nursal Melda Yenerel,1 Raciha Beril Kucumen,2 Ebru Gorgun3 1Haydarpasa Numune Research and Training Hospital, Istanbul, Turkey; 2Yeditepe University Medical Faculty, Department of Ophthalmology, Istanbul, Turkey; 3Dunya Goz Eye Hospital, Istanbul, Turkey Purpose: To evaluate the utility of anterior segment optical coherence tomography (AS-OCT assessment in the pre- and postsurgical management of full-thickness corneal grafts. Methods: Seventy eyes of 58 patients who had penetrating keratoplasty were included in the study. High resolution AS-OCT scans of the cornea and the anterior segment were performed before and after transplantation in 17 eyes with the VisanteTM optical coherence tomography. Fifty-three eyes were examined in the late postoperative period. Results: The mean follow-up was 4.3 years (range, 1–15 years. Six different graft–host junctions were identified. Three patients with graft rejection, four patients with anterior synechia, and three patients with corneal ulcer were evaluated. Preoperative evaluation of eyes with semiopaque and totally opaque corneas revealed important information about anterior segment structures additional to slit-lamp findings. Conclusion: AS-OCT is a useful complementary tool for the evaluation of penetrating corneal transplantation surgery and in the management of its postoperative complications. Keywords: anterior segment optical coherence tomography, imaging techniques, penetrating keratoplasty

  2. "Double bubble" deep anterior lamellar keratoplasty for management of corneal stromal pathologies.

    Science.gov (United States)

    Jhanji, Vishal; Beltz, Jacqueline; Sharma, Namrata; Graue, Enrique; Vajpayee, Rasik B

    2011-08-01

    'Big Bubble' deep anterior lamellar keratoplasty (DALK) is becoming an accepted corneal transplantation technique for keratoconus and other anterior stromal corneal pathologies that spare the Descemet's membrane (DM) and endothelium. However, it is not always possible to conclusively recognise formation and identification of the 'Big Bubble'. We describe the surgical technique of DALK called 'Double Bubble' technique that allows the surgeon to definitely and immediately identify the formation of an adequate big bubble. DALK was performed using the 'Double Bubble' technique in twelve eyes of twelve patients with corneal stromal pathologies (keratoconus, 9 eyes; macular corneal dystrophy, 2 eyes; postinfectious keratitis corneal stromal scar, 1 eye) at the Royal Victorian Eye and Ear Hospital, Melbourne. Big bubble was successfully formed in 10 eyes. Maximum-depth deep lamellar keratoplasty was performed in two eyes. There were no instances of intraoperative perforation of the DM. All grafts were clear at last follow-up. Best-corrected visual acuity of ≥20/40 was achieved in all the cases at last follow-up (6-12 months). 'Double Bubble' DALK helps in identification of the big bubble and has the potential to increase the success of standard 'Big Bubble' DALK in patients with corneal stromal pathologies sparing the DM and endothelium.

  3. Intracameral air following pneumatic noncontact tonometry in a recently post–perforating keratoplasty patient

    Directory of Open Access Journals (Sweden)

    Vámosi P

    2014-04-01

    Full Text Available Péter VámosiDepartment of Ophthalmology, Péterfy Sándor Hospital, Budapest, Department of Ophthalmology, Medical and Health Science Centre, University of Debrecen, Debrecen, HungaryPurpose: The purpose of this report is to highlight the potential risk of noncontact tonometry after routine uncomplicated penetrating keratoplasty (PK.Case report: After uncomplicated PK for keratoconus, routine noncontact tonometry was performed on the second postoperative day. In spite of the adequately closed wound and the tight suture, temporary wound dehiscence occurred, and two-thirds of the anterior chamber was occupied by air. The running suture remained intact, and the Seidel test was negative. One week postoperatively, the patient’s corrected distance visual acuity was 0.4 (0.4 logMAR, and the air bubble had absorbed.Conclusion: This is the first report to conclude that noncontact tonometry may not be sufficiently safe in the early postoperative period in normal PK cases. To prevent possible wound opening, we suggest the use of other tonometry methods during the first several months after PK.Keywords: wound dehiscence, penetrating keratoplasty

  4. Laser-assisted lipolysis for arm contouring in Teimourian grades I and II: a prospective study of 45 patients.

    Science.gov (United States)

    Leclère, Franck Marie; Alcolea, Justo M; Vogt, Peter; Moreno-Moraga, Javier; Mordon, Serge; Casoli, Vincent; Trelles, Mario A

    2015-04-01

    Upper arm deformities secondary to weight loss or senile elastosis have led to an increased demand for aesthetic contouring procedures. We conducted this study to objectively assess if, in Teimourian low-grade upper arm remodelling, one session of laser-assisted lypolisis (LAL) could result in full patient satisfaction. Between 2011 and 2013, 45 patients were treated for unsightly fat arm Teimourian grade I (15 patients), grade IIa (15 patients) and grade IIb (15 patients) with one session of LAL. The laser used in this study was a 1470-nm diode laser (Alma Lasers, Cesarea, Israel) with the following parameters: continuous mode, 15 W power and transmission through a 600-μm optical fibre. Previous mathematical modelling suggested that 0.1 kJ was required in order to destroy 1 ml of fat. Treatment parameters and adverse effects were recorded.The arm circumference and skin pinch measurements were assessed pre and postoperatively. Patients were asked to file a satisfaction questionnaire. Pain during the anaesthesia and discomfort after the procedure were minimal. Complications included prolonged oedema in 11 patients. The average arm circumference decreased by 4.9 ± 0.4 cm in the right arm (p < 0.01) and 4.7 ± 0.5 cm in the left arm (p < 0.01) in grade I patients, 5.5 ± 0.6 cm in the right arm (p < 0.01) and 5.2 ± 0.5 cm in the left arm (p < 0.01) in grade IIa patients and 5.4 ± 0.5 cm in the right arm (p < 0.01) and 5.3 ± 0.5 cm in the left arm (p < 0.01) in grade IIB patients. The skin tightening effect was confirmed by the reduction of the skin calliper measurements in all three groups. Overall mean opinion of treatment was high for both patients and investigators. Of the 45 patients, all but one would recommend this treatment. A single session of LAL in upper arm remodelling for Teimourian grades I to IIb is a safe and reproducible technique. The procedure allows reduction in the amount of adipose deposits

  5. Investigations of the potential functions of weakly bound diatomic molecules and laser-assisted excitive Penning ionization

    Energy Technology Data Exchange (ETDEWEB)

    Goble, J.H. Jr.

    1982-05-01

    Three variations on the Dunham series expansion function of the potential of a diatomic molecule are compared. The differences among these expansions lie in the choice of the expansion variable, lambda. The functional form of these variables are lambda/sub s/ = l-r/sub e//r for the Simon-Parr-Finlan version, lambda/sub T/ - 1-(r/sub e//r)/sup p/ for that of Thakkar, and lambda/sub H/ = 1-exp(-rho(r/r/sub e/-1) for that of Huffaker. A wide selection of molecular systems are examined. It is found that, for potentials in excess of thirty kcal/mole, the Huffaker expansion provides the best description of the three, extrapolating at large internuclear separation to a value within 10% of the true dissociation energy. For potentials that result from the interaction of excited states, all series expansions show poor behavior away from the equilibrium internuclear separation of the molecule. The series representation of the potentials of weakly bound molecules are examined in more detail. The ground states of BeAr/sup +/, HeNe/sup +/, NaAr, and Ar/sub 2/ and the excited states of HeNe+, NaNe, and NaAr are best described by the Thakkar expansion. Finally, the observation of laser-assisted excitive Penning ionization in a flowing afterglow is reported. The reaction Ar(/sup 3/P/sub 2/) + Ca + h nu ..-->.. Ar + Ca/sup +/(5p /sup 2/P/sub J/) + e/sup -/ occurs when the photon energy, h nu, is approximately equal to the energy difference between the metastable argon and one of the fine structure levels of the ion's doublet. By monitoring the cascade fluorescence of the above reaction and comparing it to the flourescence from the field-free process Ar(/sup 3/P/sub 2/) + Ca ..-->.. Ar + Ca/sup +/(4p /sup 2/P/sub J/) + e/sup -/ a surprisingly large cross section of 6.7 x 10/sup 3/ A/sup 2/ is estimated.

  6. All-fiber femtosecond Cherenkov radiation source

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Møller, Uffe

    2012-01-01

    An all-fiber femtosecond source of spectrally isolated Cherenkov radiation is reported, to the best of our knowledge, for the first time. Using a monolithic, self-starting femtosecond Yb-doped fiber laser as the pump source and the combination of photonic crystal fibers as the wave-conversion med......An all-fiber femtosecond source of spectrally isolated Cherenkov radiation is reported, to the best of our knowledge, for the first time. Using a monolithic, self-starting femtosecond Yb-doped fiber laser as the pump source and the combination of photonic crystal fibers as the wave......-conversion medium, we demonstrate milliwatt-level, stable, and tunable Cherenkov radiation at visible wavelengths 580–630 nm, with pulse duration of sub-160-fs, and the 3 dB spectral bandwidth not exceeding 36 nm. Such an all-fiber Cherenkov radiation source is promising for practical applications in biophotonics...

  7. 2 micron femtosecond fiber laser

    Science.gov (United States)

    Liu, Jian; Wan, Peng; Yang, Lihmei

    2014-07-29

    Methods and systems for generating femtosecond fiber laser pulses are disclose, including generating a signal laser pulse from a seed laser oscillator; using a first amplifier stage comprising an input and an output, wherein the signal laser pulse is coupled into the input of the first stage amplifier and the output of the first amplifier stage emits an amplified and stretched signal laser pulse; using an amplifier chain comprising an input and an output, wherein the amplified and stretched signal laser pulse from the output of the first amplifier stage is coupled into the input of the amplifier chain and the output of the amplifier chain emits a further amplified, stretched signal laser pulse. Other embodiments are described and claimed.

  8. Femtosecond optical studies of cuprates

    Science.gov (United States)

    Schneider, Michael L.; Rast, S.; Onellion, Marshall; Demsar, Jure; Taylor, Antoinette J.; Glinka, Yu D.; Tolk, Norman H.; Ren, Yuhang; Luepke, Gunter; Klimov, A.; Xu, Ying; Sobolewski, Roman; Si, Weidong; Zeng, X. H.; Soukiassian, A.; Xi, Xiaoxing; Abrecht, M.; Ariosa, Daniel; Pavuna, Davor; Manzke, Recardo; Printz, J. O.; Parkhurst, D. K.; Downum, K. E.; Guptasarma, P.; Bozovic, Ivan

    2002-11-01

    Femtosecond optical reflectivity measurements of La2-xSrxCuO4, La2CuO4+y, Bi2Sr2CuO6+z and Bi2Sr2CaCu2O8+δ thin films and single crystal samples indicate qualitative changes with fluence. At the lowest fluencies, there is a power law divergence in the relaxation time. The divergence has an onset temperature of 55+/-15K, independent of whether the sample is in the superconducting or normal states. At slightly higher fluencies, still perturbative, the additional response does not exhibit this power law divergence. At quite high fluencies- no longer perturbative- the metallic samples exhibit oscillations in the reflectivity amplitude. The period of these oscillations varies with the probe wavelength but not with the pump wavelength. The oscillations exhibit a decay time as long as 10 nsec.

  9. Transient, three-dimensional heat transfer model for the laser assisted machining of silicon nitride: 1. Comparison of predictions with measured surface temperature histories

    Energy Technology Data Exchange (ETDEWEB)

    Rozzi, J.C.; Pfefferkorn, F.E.; Shin, Y.C. [Purdue University, (United States). Laser Assisted Materials Processing Laboratory, School of Mechanical Engineering; Incropera, F.P. [University of Notre Dame, (United States). Aerospace and Mechanical Engineering Department

    2000-04-01

    Laser assisted machining (LAM), in which the material is locally heated by an intense laser source prior to material removal, provides an alternative machining process with the potential to yield higher material removal rates, as well as improved control of workpiece properties and geometry, for difficult-to-machine materials such as structural ceramics. To assess the feasibility of the LAM process and to obtain an improved understanding of governing physical phenomena, experiments have been performed to determine the thermal response of a rotating silicon nitride workpiece undergoing heating by a translating CO{sub 2} laser and material removal by a cutting tool. Using a focused laser pyrometer, surface temperature histories were measured to determine the effect of the rotational and translational speeds, the depth of cut, the laser-tool lead distance, and the laser beam diameter and power on thermal conditions. The measurements are in excellent agreement with predictions based on a transient, three-dimensional numerical solution of the heating and material removal processes. The temperature distribution within the unmachined workpiece is most strongly influenced by the laser power and laser-tool lead distance, as well as by the laser/tool translational velocity. A minimum allowable operating temperature in the material removal region corresponds to the YSiAlON glass transition temperature, below which tool fracture may occur. In a companion paper, the numerical model is used to further elucidate thermal conditions associated with laser assisted machining. (author)

  10. Performance Improvement of Microcrystalline p-SiC/i-Si/n-Si Thin Film Solar Cells by Using Laser-Assisted Plasma Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Hsin-Ying Lee

    2014-01-01

    Full Text Available The microcrystalline p-SiC/i-Si/n-Si thin film solar cells treated with hydrogen plasma were fabricated at low temperature using a CO2 laser-assisted plasma enhanced chemical vapor deposition (LAPECVD system. According to the micro-Raman results, the i-Si films shifted from 482 cm−1 to 512 cm−1 as the assisting laser power increased from 0 W to 80 W, which indicated a gradual transformation from amorphous to crystalline Si. From X-ray diffraction (XRD results, the microcrystalline i-Si films with (111, (220, and (311 diffraction were obtained. Compared with the Si-based thin film solar cells deposited without laser assistance, the short-circuit current density and the power conversion efficiency of the solar cells with assisting laser power of 80 W were improved from 14.38 mA/cm2 to 18.16 mA/cm2 and from 6.89% to 8.58%, respectively.

  11. Effects of Laser Energy and Wavelength on the Analysis of LiFePO4 Using Laser Assisted Atom Probe Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Santhanagopalan, Dhamodaran; Schreiber, Daniel K.; Perea, Daniel E.; Martens, Rich; Janssen, Yuri; Kalifah, Peter; Meng, Ying S.

    2015-01-21

    The effects of laser wavelength (355 nm and 532 nm) and laser pulse energy on the quantitative accuracy of atom probe tomography (APT) examinations of LiFePO4 (LFP) are considered. A systematic investigation of ultraviolet (UV, 355 nm) and green (532 nm) laser assisted APT of LFP has revealed distinctly different behaviors. With the use of UV laser the major issue was identified as the preferential loss of oxygen (up to 10 at. %) while other elements (Li, Fe and P) were observed to be close to nominal ratios. Lowering the laser energy per pulse to 1 pJ increased the observed oxygen concentration to near its correct stoichiometry and was well correlated with systematically higher concentrations of 16O2+ ions. This observation supports the premise that lower laser energies lead to a higher probability of oxygen molecule ionization. Conversely, at higher laser energies the resultant lower effective electric field reduces the probability of oxygen molecule ionization. Green laser assisted field evaporation led to the selective loss of Li (~50% deficiency) and correct ratios of the remaining elements, including the oxygen concentration. The loss of Li is explained by selective dc evaporation of lithium between laser pulses and relatively negligible oxygen loss as neutrals during green-laser pulsing. Lastly, plotting of multihit events on a Saxey plot for the straight-flight path data (green laser only) revealed a surprising dynamic recombination process for some molecular ions mid-flight.

  12. Effectiveness and safety of endothelial keratoplasty for pseudophakic and aphakic bullous keratopathy: a systematic review of randomized controlled trials and cohort studies

    Directory of Open Access Journals (Sweden)

    Bruno Harfuch

    2016-06-01

    Full Text Available ABSTRACT Objective: For nearly a century, penetrating keratoplasty has been the surgical technique of choice in the management of corneal changes. However, in recent years, several lamellar keratoplasty techniques have been developed, modified or improved, especially techniques for replacing the posterior portion, for the correction of bullous keratopathy. The aim of this study was to evaluate the effectiveness and safety of endothelial keratoplasty versus penetrating keratoplasty for pseudophakic and aphakic bullous keratopathy. Methods: A systematic review of the literature was carried out, and the main electronic databases were searched. The date of the most recent search was from the inception of the electronic databases to December 11, 2015. Two authors independently selected relevant clinical trials, assessed their methodological quality and extracted data. Results: The electronic search yielded a total of 893 published papers from the electronic databases. Forty-four full-text articles were retrieved for further consideration. Of these 44 full-text articles, 33 were excluded because they were all case series studies; therefore, ten studies (with one further publication met the inclusion criteria: one randomized clinical trial with two publications; three controlled studies; and six cohort studies. The clinical and methodological diversity found in the included studies meant that it was not possible to combine studies in a metaanalysis. Conclusions: There is no robust evidence that endothelial keratoplasty is more effective and safe than penetrating keratoplasty for improving visual acuity and decreasing corneal rejection for pseudophakic and aphakic bullous keratopathy. There is a need for further randomized controlled trials.

  13. Descemet membrane endothelial keratoplasty with a stromal rim in the treatment of posterior polymorphous corneal dystrophy

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    Pavel Studeny

    2012-01-01

    Full Text Available A 20-year-old patient, diagnosed with posterior polymorphous corneal dystrophy, developed corneal edema for which he underwent Descemet membrane endothelial keratoplasty with a stromal rim (DMEK-S in the right eye. No intra- or postoperative complications were noted. At the last follow-up 2 years and 9 months after the procedure, the best corrected visual acuity was 1.0 and endothelial cell density declined from 3533 cells/mm 2 to 1012 cells/mm 2 . Despite the endothelial cell loss, DMEK-S appears to be a good alternative to other surgical techniques for the treatment of corneal endotheliopathies, and it may be of benefit to young patients.

  14. Graft Suturing for Lenticule Dislocation after Descemet Stripping Automated Endothelial Keratoplasty

    Directory of Open Access Journals (Sweden)

    Wai-Kwan Wu

    2011-01-01

    Full Text Available Purpose: To report the mid-term outcomes of graft suturing in a patient with lenticule dislocation after Descemet stripping automated endothelial keratoplasty (DSAEK. Case Report: A 78-year old woman was found to have graft dislocation involving the nasal half of the cornea after uneventful DSAEK. Graft repositioning, refilling the anterior chamber with air, and placement of four full-thickness 10/0 nylon sutures over the detached area were performed two weeks after the initial surgery. The sutures were removed 6 weeks later. Serial specular microscopy and anterior segment optical coherence tomography were performed. At 18 months, there was good lenticule apposition and a clear graft. Conclusion: Anchoring sutures seem to be effective for management of graft detachment following DSAEK.

  15. Staged Penetrating Sclerokeratoplasty and Penetrating Keratoplasty for Management of Advanced Acquired Anterior Staphyloma

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    Enrique de la Torre-Gonzalez

    2011-01-01

    Full Text Available Herein we describe a staged surgical technique consisting of penetrating sclerokeratoplasty (PSKP followed by penetrating keratoplasty (PKP and present its clinical course and complications over two years of follow-up. A 23-year-old man presented with cosmetically unacceptable protrusion of the globe corresponding to the cornea and sclera. PSKP was performed transplanting a full-thickness beveled 13 mm corneoscleral tectonic graft. Hypotony developed subsequently and was successfully managed medically, however corneal graft failure occurred. After 15 months, a 7.5 mm PKP was performed for optical reasons, which subsequently remained clear with a healthy epithelium. In this particular case, cosmetic, tectonic, therapeutic, and optical requirements were met. PSKP is a surgical procedure which entails a high rate of complications but may be the only alternative when the main goal of intervention is restoration of the globe in complicated cases such as our patient.

  16. Phacoemulsification after penetrating keratoplasty with autologous limbal transplant and amniotic membrane transplant in chemical burns

    Directory of Open Access Journals (Sweden)

    Arora Ritu

    2005-01-01

    Full Text Available We report a patient who had earlier penetrating keratoplasty with amniotic membrane transplant and autologous limbal cell transplant for chemical injury who underwent cataract surgery by phacoaspiration. A posterior limbal incision with corneal valve was made superotemporally with extreme caution to avoid damage to the limbal graft. Aspiration flow rates and vacuum were kept low to avoid any turbulence during surgery. A 6.0 mm optic diameter acrylic foldable intraocular lens was inserted in the bag. The patient achieved a best-corrected visual acuity of 6/12 at 10 months′ follow-up with a clear corneal graft. We conclude that caution during wound construction and phacoaspiration can help preserve corneal and limbal graft integrity in patients undergoing cataract surgery after corneal graft and limbal transplantation.

  17. [Confocal microscopy as an early relapse marker after keratoplasty due to Fusarium solani keratitis].

    Science.gov (United States)

    Daas, L; Bischoff-Jung, M; Viestenz, A; Seitz, B; Viestenz, A

    2017-01-01

    In the case of therapy-resistant keratitis an infection with Fusarium solani should be taken into consideration as a rare but very severe eye disease. In the majority of cases Fusarium solani keratitis will result in a protracted clinical course despite aggressive medicinal and surgical interventions. We describe the case of a referred patient after intensive topical, intracameral and systemic antibacterial and antimycotic therapy as well as surgical treatment with emergency keratoplasty à chaud because of Fusarium solani keratitis. The patient presented to our department with persistent discomfort for further therapeutic interventions. Using confocal microscopy we were able to demonstrate the presence of fungal hyphae in the host cornea and the graft, which was important for making further surgical decisions. Furthermore, this emphasizes the role of confocal microscopy as an early relapse marker during the clinical monitoring.

  18. Using femtosecond laser to create customized corneal flaps for patients with low and moderate refractive error differing in corneal thickness.

    Science.gov (United States)

    Zhang, Chi; Che, Jingbin; Yu, Jianhong; Yu, Linli; Yu, Dan; Zhao, Gangping

    2015-01-01

    This study is designed to evaluate the visual outcomes, accuracy, and predictability of corneal flaps with different thicknesses created by 60-kHz femtosecond laser according to different corneal thicknesses in the patients with low and moderate refractive error. A total of 182 eyes were divided according to the central corneal thickness (470 μm-499 μm in Group A, 500 μm-549 μm in Group B, and 550 μm-599 μm in Group C) and underwent femtosecond laser-assisted LASIK for a target corneal flap thickness (100 μm for Group A, 110 μm for Group B, and 120 μm for Group C). Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and refractive status were examined. The flap thickness of each eye was measured by anterior segment optical coherence tomography (AS-OCT) on 30 points at 1-month follow-up to assess the accuracy and predictability. Postoperatively, at least 75% of eyes had a UDVA of 20/16 or better, less than 2% of eyes lost one line, over 30% of eyes gained one or more lines in CDVA, at least 95% of eyes had astigmatism of less than 0.25 D, all eyes achieved a correction within ± 1.00 D from the target spherical equivalent refraction. The visual and refractive outcomes did not differ significantly in all groups (P >0.05). The mean flap thickness was 100.36 ± 4.32 μm (range: 95-113 μm) in Group A, 111.64 ± 3.62 μm (range: 108-125 μm) in Group B, and 122.32 ± 2.88 μm (range: 112-128 μm) in Group C. The difference at each measured point among the three groups was significant (P refractive error.

  19. Evaluation of internationally shipped prestripped donor tissue for descemet membrane endothelial keratoplasty by vital dye staining.

    Science.gov (United States)

    Kobayashi, Akira; Murata, Noriaki; Yokogawa, Hideaki; Yamazaki, Natsuko; Masaki, Toshinori; Sugiyama, Kazuhisa

    2015-02-01

    The aim of this study was to evaluate endothelial cell damage of internationally shipped prestripped donor tissue for Descemet membrane endothelial keratoplasty (DMEK) using vital dye staining. Six internationally shipped prestripped DMEK donors were stained with trypan blue and were subsequently photographed before they were cut with a trephine. Quantitative analysis assessment of endothelial damage of the donor graft area (8.0 mm in diameter) was performed using Adobe Photoshop CS6 Extended software. Seven internationally shipped precut Descemet stripping automated endothelial keratoplasty (DSAEK) donors were used as controls. No statistical differences were noted between prestripped DMEK donors and precut DSAEK donors in mean donor age (67.7 vs. 56.4 years, P = 0.222), mean donor endothelial cell density (2687.3 vs. 2894.6 cells, P = 0.353), and death-to-preservation time (405.3 vs. 558.4 minutes, P = 0.173). However, the mean time of death-to-experiment time in DMEK donors was significantly longer than that of DSAEK donors (8.7 vs. 6.6 days, P = 0.031). Mean endothelial cell damage of prestripped DMEK donors was as low as 0.3%. However, DMEK donor endothelial damage (0.3%) was significantly higher compared with that of precut DSAEK donor tissue (0.01%, P = 0.029). Although endothelial damage of internationally shipped prestripped donor tissue for DMEK was higher than that of precut DSAEK donor, it was extremely low. Further evaluation using another vital dye and clinical studies may be needed to confirm this study.

  20. Quantification of collagen ultrastructure after penetrating keratoplasty - implications for corneal biomechanics.

    Directory of Open Access Journals (Sweden)

    Craig Boote

    Full Text Available PURPOSE: To quantify long-term changes in stromal collagen ultrastructure following penetrating keratoplasty (PK, and evaluate their possible implications for corneal biomechanics. METHODS: A pair of 16 mm post-mortem corneo-scleral buttons was obtained from a patient receiving bilateral penetrating keratoplasty 12 (left/28 (right years previously. Small-angle x-ray scattering quantified collagen fibril spacing, diameter and spatial order at 0.5 mm or 0.25 mm intervals along linear scans across the graft margin. Corresponding control data was collected from two corneo-scleral buttons with no history of refractive surgery. Wide-angle x-ray scattering quantified collagen fibril orientation at 0.25 mm (horizontal×0.25 mm (vertical intervals across both PK specimens. Quantification of orientation changes in the graft margin were verified by equivalent analysis of data from a 13 year post-operative right PK specimen obtained from a second patient in a previous study, and comparison made with new and published data from normal corneas. RESULTS: Marked changes to normal fibril alignment, in favour of tangentially oriented collagen, were observed around the entire graft margin in all PK specimens. The total number of meridional fibrils in the wound margin was observed to decrease by up to 40%, with the number of tangentially oriented fibrils increasing by up to 46%. As a result, in some locations the number of fibrils aligned parallel to the wound outnumbered those spanning it by up to five times. Localised increases in fibril spacing and diameter, with an accompanying reduction in matrix order, were also evident. CONCLUSIONS: Abnormal collagen fibril size and spatial order within the PK graft margin are indicative of incomplete stromal wound remodelling and the long term persistence of fibrotic scar tissue. Lasting changes in collagen fibril orientation in and around PK wounds may alter corneal biomechanics and compromise the integrity of the graft

  1. Outcome of optical penetrating keratoplasties at a tertiary care eye institute in Western India

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    Shilpa A Joshi

    2012-01-01

    Full Text Available Aim: To study the indications, risk factors, postoperative course, and long-term survival of corneal transplants done for optical purposes. Design: Retrospective case series. Materials and Methods: Data were obtained by reviewing the records of 181 patients operated at our institute (H.V. Desai Eye Hospital between October 2005 and October 2007 for optical penetrating keratoplasty. Patients with less than one year of follow up, pediatric cases, therapeutic, tectonic, and lamellar keratoplasties were excluded. Kaplan Meier survival analysis was used to calculate median survival time of grafts and to see correlation between nine variables viz. age, gender, corneal vascularization, previous failed grafts, previous Herpes Simplex keratitis, post-perforation corneal scars, donor tissue quality, graft size, type of surgery and follow-up. These variables were also used for univariate and multivariate analysis using Cox Proportional Hazard Regression Modeling. Results: Median survival of the cohort was 27 months (95% confidence interval: 20.47-33.52. One- and two-year survival rates were 65% and 52.5%, respectively. Median survival was significantly lower in poor prognosis cases (14 months than good prognosis cases (27 months, P = 0.0405. Graft survival was lower in vascularized corneas (18.55 months, P = 0.030 and in post-perforation corneal scars (17.96 months, P = 0.09, borderline significance. Multivariate analysis showed that the same factors were predictive of graft failure. Conclusion: Long-term survival of grafts at our center is different from centers in western world. More high-risk cases, paucity of excellent quality donor corneas, and differences in patient profile could be the contributory factors.

  2. Intra-individual variability of penetrating keratoplasty outcome after excimer laser versus motorized corneal trephination.

    Science.gov (United States)

    Szentmáry, Nóra; Langenbucher, Achim; Naumann, Gottfried O H; Seitz, Berthold

    2006-10-01

    To assess the intra-individual variability of outcomes after penetrating keratoplasty by comparing mechanical and nonmechanical corneal trephination. Fifteen patients (30 eyes, 16 with keratoconus and 14 with Fuchs' dystrophy; median age at penetrating keratoplasty 56.3/53.5 years) were assessed whose trephination was performed using a motor trephine in one eye and the 193-nm excimer laser (MEL 60, Carl Zeiss-Meditec) in the other eye by one experienced surgeon. Subjective refractometry, standard keratometry, and corneal topography were used to assess best spectacle-corrected visual acuity (BSCVA); spherical equivalent refraction; keratometric and topographic central corneal power; refractive, keratometric, and topographic astigmatism; surface regularity index; surface asymmetry index; and potential visual acuity preoperatively, before first suture removal (at 1 year), and at last available follow-up after final suture removal but before additional surgery (1.3 and 1.9 years, respectively). Before first suture removal BSCVA was significantly higher (0.7 vs 0.5; P=.008) after excimer laser trephination. At the end of follow-up, refractive/ keratometric/topographic astigmatism (2.20/2.10/2.40 diopters [D] vs 5.00/6.00/7.10 D) and surface regularity index (0.8 vs 1.1) were significantly lower (P=.02, P=.005, P=.01, and P=.03, respectively) and potential visual acuity was significantly higher (0.9/0.6; P=.02) after excimer laser trephination. During long-term follow-up, all-sutures-out postkeratoplasty astigmatism and surface regularity are superior in the eye where nonmechanical excimer laser was applied in contrast to the fellow eye with motor trephination in the same individual.

  3. Femtosecond laser ablation of enamel

    Science.gov (United States)

    Le, Quang-Tri; Bertrand, Caroline; Vilar, Rui

    2016-06-01

    The surface topographical, compositional, and structural modifications induced in human enamel by femtosecond laser ablation is studied. The laser treatments were performed using a Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs and 1030 nm) and fluences up to 14 J/cm2. The ablation surfaces were studied by scanning electron microscopy, grazing incidence x-ray diffraction, and micro-Raman spectroscopy. Regardless of the fluence, the ablation surfaces were covered by a layer of resolidified material, indicating that ablation is accompanied by melting of hydroxyapatite. This layer presented pores and exploded gas bubbles, created by the release of gaseous decomposition products of hydroxyapatite (CO2 and H2O) within the liquid phase. In the specimen treated with 1-kHz repetition frequency and 14 J/cm2, thickness of the resolidified material is in the range of 300 to 900 nm. The micro-Raman analysis revealed that the resolidified material contains amorphous calcium phosphate, while grazing incidence x-ray diffraction analysis allowed detecting traces of a calcium phosphate other than hydroxyapatite, probably β-tricalcium phosphate Ca3), at the surface of this specimen. The present results show that the ablation of enamel involves melting of enamel's hydroxyapatite, but the thickness of the altered layer is very small and thermal damage of the remaining material is negligible.

  4. A Technique to Salvage Big-Bubble Deep Anterior Lamellar Keratoplasty after Inadvertent Full-Thickness Trephination

    Directory of Open Access Journals (Sweden)

    Siamak Zarei-Ghanavati

    2011-01-01

    Full Text Available Herein we describe a technique for management of large inadvertent full-thickness trephination during deep anterior lamellar keratoplasty using the big-bubble technique without converting to penetrating keratoplasty. First, the anterior chamber is formed with an ophthalmic viscosurgical device (OVD. Then, the full-thickness wound is secured with one X-type 10-0 nylon suture. A 27-gauge needle is attached to a 2 ml air-filled syringe and inserted into the corneal stroma in the meridian opposite to the site of full-thickness trephination. Air is gently injected to produce a limited area of "big-bubble" detaching Descemet′s membrane (DM from the corneal stroma. The "big bubble" is slowly expanded with injection of OVD. Finally, the recipient stroma is removed, the donor lenticule is placed and the DM tear is secured with one full thickness 10-0 nylon suture.

  5. A technique to salvage big-bubble deep anterior lamellar keratoplasty after inadvertent full-thickness trephination.

    Science.gov (United States)

    Zarei-Ghanavati, Siamak; Zarei-Ghanavati, Mehran

    2011-01-01

    Herein we describe a technique for management of large inadvertent full-thickness trephination during deep anterior lamellar keratoplasty using the big-bubble technique without converting to penetrating keratoplasty. First, the anterior chamber is formed with an ophthalmic viscosurgical device (OVD). Then, the full-thickness wound is secured with one X-type 10-0 nylon suture. A 27-gauge needle is attached to a 2 ml air-filled syringe and inserted into the corneal stroma in the meridian opposite to the site of full-thickness trephination. Air is gently injected to produce a limited area of "big-bubble" detaching Descemet's membrane (DM) from the corneal stroma. The "big bubble" is slowly expanded with injection of OVD. Finally, the recipient stroma is removed, the donor lenticule is placed and the DM tear is secured with one full thickness 10-0 nylon suture.

  6. Femtosecond laser cutting of endothelial grafts: comparison of endothelial and epithelial applanation.

    Science.gov (United States)

    Bernard, Aurélien; He, Zhiguo; Gauthier, Anne Sophie; Trone, Marie Caroline; Baubeau, Emmanuel; Forest, Fabien; Dumollard, Jean Marc; Peocʼh, Michel; Thuret, Gilles; Gain, Philippe

    2015-02-01

    Stromal surface quality of endothelial lamellae cut for endothelial keratoplasty with a femtosecond laser (FSL) with epithelial applanation remains disappointing. Applanation of the endothelial side of the cornea, mounted inverted on an artificial chamber, has therefore been proposed to improve cut quality. We compared lamellar quality after FSL cutting using epithelial versus endothelial applanation. Lamellae were cut with an FSL from organ-cultured corneas. After randomization, 7 were cut with epithelial applanation and 7 with endothelial applanation. Lamellae of 50-, 75-, and 100-μm thickness were targeted. Thickness was measured by optical coherence tomography before and immediately after cutting. Viable endothelial cell density was quantified immediately after cutting using triple labeling with Hoechst/ethidium/calcein-AM coupled with image analysis with ImageJ. The stromal surface was evaluated by 9 masked observers using semiquantitative scoring of scanning electronic microscopy images. Histology of 2 samples was also analyzed before lamellar detachment. Precision (difference in target/actual thickness) and thickness regularity [coefficient of variation (CV) of 10 measurements] were significantly better with endothelial applanation (precision: 18 μm; range, 10-30; CV: 11%; range, 8-12) than with epithelial applanation (precision: 84 μm; range, 54-107; P = 0.002; CV: 24%; range, 13-47; P = 0.001). Endothelial applanation provided thinner lamellae. However, viable endothelial cell density was significantly lower after endothelial applanation (1183 cells/mm2; range, 787-1725 versus 1688 cells/mm2; range, 1288-2025; P = 0.018). FSL cutting of endothelial lamellae using endothelial applanation provides thinner more regular grafts with more predictable thickness than with conventional epithelial applanation but strongly reduces the pool of viable endothelial cells.

  7. Femtosecond fabricated surfaces for cell biology

    Science.gov (United States)

    Day, Daniel; Gu, Min

    2010-08-01

    Microfabrication using femtosecond pulse lasers is enabling access to a range of structures, surfaces and materials that was not previously available for scientific and engineering applications. The ability to produce micrometre sized features directly in polymer and metal substrates is demonstrated with applications in cell biology. The size, shape and aspect ratio of the etched features can be precisely controlled through the manipulation of the fluence of the laser etching process with respect to the properties of the target material. Femtosecond laser etching of poly(methyl methacrylate) and aluminium substrates has enabled the production of micrometre resolution moulds that can be accurately replicated using soft lithography. The moulded surfaces are used in the imaging of T cells and demonstrate the improved ability to observe biological events over time periods greater than 10 h. These results indicate the great potential femtosecond pulse lasers may have in the future manufacturing of microstructured surfaces and devices.

  8. Changing Practice Patterns and Long-term Outcomes of Endothelial Versus Penetrating Keratoplasty: A Prospective Dutch Registry Study.

    Science.gov (United States)

    Dickman, Mor M; Peeters, Jean Marie P W U; van den Biggelaar, Frank J H M; Ambergen, Ton A W; van Dongen, Martin C J M; Kruit, Pieter Jan; Nuijts, Rudy M M A

    2016-10-01

    To compare graft survival, best-corrected visual acuity (BCVA), endothelial cell density (ECD), and refraction following penetrating keratoplasty (PK) vs endothelial keratoplasty (EK) for Fuchs endothelial dystrophy (FED) and pseudophakic bullous keratopathy (PBK). Nonrandomized treatment comparison with national registry data. All consecutive patients undergoing first keratoplasty for FED and PBK between 1998 and 2014 were analyzed, with a maximum follow-up of 5 years (mean ± SD follow-up 39 ± 20 months, range 0-60 months). Graft survival was analyzed using Kaplan-Meier survival curves and Cox regression analysis. BCVA, ECD, and refractive error were compared using linear mixed models. Main outcome measures were graft survival, BCVA, refraction, and ECD. A total of 5115 keratoplasties (PK = 2390; EK = 2725) were identified. Two-year graft survival following EK was lower compared with PK (94.5% vs 96.3%, HR = 1.56, P = .001). Five-year survival was comparable for EK and PK (93.4% vs 89.7%, HR = 0.89, P = .261). EK graft survival improved significantly over time while remaining stable for PK. One-year BCVA was better following EK vs PK (0.34 vs 0.47 logMAR, P < .001). Astigmatism was lower 1 year after EK vs PK (-1.69 vs -3.52 D, P < .001). One-year ECD was lower after EK vs PK (1472 vs 1859 cells/mm(2), P < .001). At 3 years, ECD did not differ between EK and PK. Long-term graft survival after EK and PK is high and comparable despite lower short-term survival for EK. EK graft survival improved over time, suggesting a learning curve. EK results in better BCVA, lower astigmatism, and similar long-term ECD compared with PK for FED and PBK. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. 飞秒激光在圆锥角膜治疗中的应用进展%Advances in application of femtosecond for keratoconus

    Institute of Scientific and Technical Information of China (English)

    董子献

    2011-01-01

    Keratoconus is a corneal ectasia disease that dramatically affects visual function.Currently,the treatment approach of keratoconus includes wearing of spectacles or contact lenses,epikeratophakia,keratoplasty,etc.Femtosecond laser is a type of infrared laser operated in pulse form,which is accurate,safe and simple in operation.This technique has been applied in keratoplasty,intrastromal corneal ring implantation and cross-linking.Combination therapy may achieve better outcome.This review focuses on the related application of femtoseeond laser in keratoconus treatment.%圆锥角膜是一种严重影响患者视功能的扩张性角膜病变,目前其治疗方式包括配戴框架眼镜或角膜接触镜、角膜表面镜片术、角膜移植术等.飞秒激光是一种以脉冲形式运转的红外线激光,精确度高,安全性好,操作简便,已在角膜移植、基质环植入及角膜胶原交联等研究领域得到了较好的应用;尤其是在角膜胶原交联中的应用可极大地改善患者的舒适程度,此外飞秒激光与多种圆锥角膜的治疗方法联合应用也会达到更好的效果.就近年来飞秒激光在圆锥角膜治疗中的相关应用进展进行综述.

  10. Utilization of laser-assisted analytical methods for monitoring of lead and nutrition elements distribution in fresh and dried Capsicum annuum l. leaves.

    Science.gov (United States)

    Galiová, Michaela; Kaiser, Jozef; Novotný, Karel; Hartl, Martin; Kizek, Rene; Babula, Petr

    2011-09-01

    Laser induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) have been applied for high-resolution mapping of accumulation and distribution of heavy metal (lead) and nutrition elements (potassium, manganese) in leaves of Capsicum annuum L. samples. Lead was added in a form of Pb(NO₃)₂ at concentration up to 10 mmol L⁻¹ into the vessels that contained tap water and where the 2-months old Capsicum annuum L. plants were grown another seven days. Two dimensional maps of the elements are presented for both laser-assisted analytical methods. Elemental mapping performed on fresh (frozen) and dried Capsicum annuum L. leaves are compared.

  11. Gas-phase photofragmentation of tris(methyl vinyl ketone) tungsten(0) and the relationship to laser-assisted CVD of tungsten oxide thin films.

    Science.gov (United States)

    Bitner, Theodore W; Zink, Jeffrey I

    2002-02-25

    The gas-phase laser-induced photofragmentation of tris(methyl vinyl ketone) tungsten(0) is studied, and the photoproducts are identified by time-of-flight mass spectroscopy. The initially populated excited electronic state of the complex is attributed to metal-to-ligand charge transfer by analysis of the electronic and preresonance Raman spectra. The major metal-containing photofragmentation products are W(+) and WO(+); smaller amounts of WC(+) and W(C(2)H(2))(+) are also observed. Intramolecular ligand coupling occurs, and dimeric products and their fragments are identified. Reaction pathways that explain the observed products are proposed. Thin films on silicon substrates are produced by laser-assisted chemical vapor deposition. The films consist of polycrystalline tungsten oxide with less than 10% tungsten carbide and are characterized by X-ray diffraction, SEM, and Auger electron spectroscopy. Relationships between the composition of the gas-phase photofragments and that of the solid films are discussed.

  12. DIAGNOSIS AND TREATMENT FOR DEGENERATIVE RETINOSCHISIS OF MEDIUM TO HIGH MYOPIA IN YOUNG ADULTS PRIOR TO LASER-ASSISTED IN SITU KERATOMILEUSIS SURGERY

    Institute of Scientific and Technical Information of China (English)

    孙昕; 冯佩丽; 闫焱

    2013-01-01

    <正>Objective To discuss the characteristics of degenerative retinoschisis in young adults with medium to high myopia prior to laser-assisted in situ keratomileusis(LASIX) surgery and the significance of preventive photocoagulation.Methods A total of 32 eyes in 19 patients suffering from myopia combined with degenerative retinoschisis were included.The mean best-corrected visual acuity was 0.82±0.13 and the mean spherical equivalent of the subjective refraction was -(6.50±3.98) Diopter. The patients underwent preventive photocoagulation 1 month before the laser surgery for myopia.Results All the eyes that received preventive photocoagulation for retinoschisis had no further progression or retinal detachment during 4-year period of follow-up.Conclusion The degenerative retinoschisis in young adults should be recognized and treated with preventive photocoagulation.This may prevent further damage of visual field and other complications of slowly progressive retinoschisis after LASIK surgery.

  13. Progress in Cherenkov femtosecond fiber lasers

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Svane, Ask Sebastian; Lægsgaard, Jesper

    2016-01-01

    systems are highlighted—dependent on the realization scheme, the Cherenkov lasers can generate the femtosecond output tunable across the entire visible and even the UV range, and for certain designs more than 40% conversion efficiency from the pump to Cherenkov signal can be achieved. The femtosecond...... Cherenkov laser with all-fiber architecture is presented and discussed. Operating in the visible range, it delivers 100–200 fs wavelength-tunable pulses with multimilliwatt output power and exceptionally low noise figure an order of magnitude lower than the traditional wavelength tunable supercontinuumbased...

  14. An experimental study on minimally occlusive laser-assisted vascular anastomosis in bypass surgery: the importance of temperature monitoring during laser welding procedures.

    Science.gov (United States)

    Esposito, G; Rossi, F; Puca, A; Albanese, A; Sabatino, G; Matteini, P; Lofrese, G; Maira, G; Pini, R

    2010-01-01

    Laser welding has been proposed as an alternative technique to conventional stitching in microvascular anastomosis, with the advantages of improving the vascular healing process and reducing the risk of malfunction of a bypass. Our group recently proposed a laser-assisted end-to-side anastomotic technique, providing the advantages of laser welding and reducing the occlusion time of the recipient vessel, that is important in neurosurgical bypass procedures, in order to reduce the risk of cerebral ischemia. This in vivo study focuses on the control of the temperature dynamics developing in the welded tissue. A jugular vein graft was harvested and implanted on the rabbit carotid artery by means of two end-to-side anastomosis. Laser welding procedure was then carried out to implant the bypass. A real-time monitoring of the temperature during welding was performed with an infrared thermocamera, in order to control the laser-induced heating effect on the external surface of the vessel walls. The temperature analysis highlighted the dynamic of the heating effect in space and time and enabled us to define an optimal temperature range in operative conditions. The temperature control provided safe tissue heating confined within the directly irradiated area, with negligible damage to surrounding tissues, as well as effective sealing and welding of the vessel edges at the anastomotic sites. The average occlusion time of the carotid artery was about 11 minutes. After a follow-up of 30 days, all the bypasses were patent and no signs of thrombosis or leak point pressure were present, thus confirming the safety of this laser-assisted anastomotic procedure.

  15. Atmospheric pressure femtosecond laser imaging mass spectrometry

    Science.gov (United States)

    Coello, Yves; Gunaratne, Tissa C.; Dantus, Marcos

    2009-02-01

    We present a novel imaging mass spectrometry technique that uses femtosecond laser pulses to directly ionize the sample. The method offers significant advantages over current techniques by eliminating the need of a laser-absorbing sample matrix, being suitable for atmospheric pressure sampling, and by providing 10μm resolution, as demonstrated here with a chemical image of vegetable cell walls.

  16. Femtosecond SESAM lasers with shortlength cavity

    Science.gov (United States)

    Trunov, V. I.; Pestryakov, Efim V.; Petrov, V. V.; Kirpichnikov, A. V.; Bordzilovskii, A. S.; Preobrazhenskii, V. V.; Putyato, M. A.; Semyagin, B. R.

    2003-10-01

    Femtosecond pulse generation in Al2O3:Ti3+ laser with some types of laser cavity configuration with semiconductor saturable absorber mirror (SESAM), based on semiconductor quantum well low temperature (LT) GaAs/AlAs, GaxIn1-xAs/AlyGa1-yAs saturated absorbers and metal mirrors have been investigated.

  17. Femtosecond laser control of chemical reactions

    CSIR Research Space (South Africa)

    Du Plessis, A

    2010-08-31

    Full Text Available Femtosecond laser control of chemical reactions is made possible through the use of pulse-shaping techniques coupled to a learning algorithm feedback loop – teaching the laser pulse to control the chemical reaction. This can result in controllable...

  18. Bending diamonds by femtosecond laser ablation

    DEFF Research Database (Denmark)

    Balling, Peter; Esberg, Jakob; Kirsebom, Kim;

    2009-01-01

    We present a new method based on femtosecond laser ablation for the fabrication of statically bent diamond crystals. Using this method, curvature radii of 1 m can easily be achieved, and the curvature obtained is very uniform. Since diamond is extremely tolerant to high radiation doses, partly due...

  19. Development of a high power femtosecond laser

    CSIR Research Space (South Africa)

    Neethling, PH

    2010-10-01

    Full Text Available the pulses from the Coherent Mira/BMI amplified femtosecond laser at the LRI. Ideally the OPCPA stage should be pumped by a 100 ? 300 ps laser with tens of mJ pulse energy, matching the stretched pulse duration. This laser will be developed by the CSIR...

  20. Microstructuring of electrospun mats employing femtosecond laser

    Directory of Open Access Journals (Sweden)

    Erika Adomavičiūtė

    2015-03-01

    Full Text Available Electrospun mats from nano/micro-fibers with control porosity and pore shape may be ideal candidate for tissue engineering scaffolds. In this study three type of poly(vinyl alcohol (PVA mats of 48-65 µm thickness with different nano/micro-fibers diameters mostly of 100-200 nm were deposited by electrospinning process. Controlled density porosity in the electrospun mats was introduced by Yb:KGW femtosecond laser micromachining system. The influence of electrospun mat micro structure, the distance between the adjacent laser ablation points, the number of femtosecond laser pulses on quality and structure of laser irradiated holes were investigated. It was demonstrated that the quality of irradiated holes depend on structure of electrospun mats (diameter of nano/micro-fibers, thickness of mats and femtosecond laser processing parameters. Varying the distance between points and number of applied femtosecond laser pulses it is possible to fabricate electrospun mats with pores of 22-36 μm diameter.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.10249

  1. Femtosecond tunneling response of surface plasmon polaritons

    DEFF Research Database (Denmark)

    Keil, Ulrich Dieter Felix; Ha, Taekjip; Jensen, Jacob Riis

    1998-01-01

    We obtain femtosecond (200 fs) time resolution using a scanning tunneling microscope on surface plasmon polaritons (SPPs) generated by two 100 fs laser beams in total internal reflection geometry. The tunneling gap dependence of the signal clearly indicates the tunneling origin of the signal...

  2. Femtosecond laser microstructuring of zirconia dental implants

    NARCIS (Netherlands)

    Delgado-Ruiz, R. A.; Calvo-Guirado, J. L.; Moreno, P.; Guardia, J.; Gomez-Moreno, G.; Mate-Sanchez, J. E.; Ramirez-Fernandez, P.; Chiva, F.

    2011-01-01

    This study evaluated the suitability of femtosecond laser for microtexturizing cylindrical zirconia dental implants surface. Sixty-six cylindrical zirconia implants were used and divided into three groups: Control group (with no laser modification), Group A (microgropored texture), and Group 13 (mic

  3. Laser welding in penetrating keratoplasty and cataract surgery of pediatric patients: early results

    Science.gov (United States)

    Rossi, Francesca; Pini, Roberto; Menabuoni, Luca; Malandrini, Alex; Canovetti, Annalisa; Lenzetti, Ivo; Capozzi, Paolo; Valente, Paola; Buzzonetti, Luca

    2013-03-01

    Diode laser welding of ocular tissues is a procedure that enables minimally invasive closure of a corneal wound. This procedure is based on a photothermal effect: a water solution of Indocyanine Green (ICG) is inserted in the surgical wound, in order to stain the corneal tissue walls. The stained tissue is then irradiated with a low power infrared diode laser, delivering laser light through a 300-μm core diameter optical fiber. This procedure enables an immediate closure of the wounds: it is thus possible to reduce or to substitute the use of surgical threads. This is of particular interest in children, because the immediate closure improves refractive outcome and anti-amblyopic effect; moreover this procedure avoids several general anaesthesia for suture management. In this work, we present the first use of diode laser welding procedure in paediatric patients. 5 selected patients underwent cataract surgery (Group 1), while 4 underwent fs-laserassisted penetrating keratoplasty (Group 2). In Group 1 the conventional surgery procedure was performed, while no stitches were used for the closure of the surgical wounds: these were laser welded and immediately closed. In Group 2 the donor button was sutured upon the recipient by 8 single stitches, instead of 16 single stitches or a running suture. The laser welding procedure was performed in order to join the donor tissue to the recipient bed. Objective observations in the follow up study evidenced a perfect adhesion of the laser welded tissues, no collateral effects and an optimal restoration of the treated tissues.

  4. Pre-banking microbial contamination of donor conjunctiva and storage medium for penetrating keratoplasty.

    Science.gov (United States)

    Inomata, Takenori; Ono, Koichi; Matsuba, Tsuyoshi; Shiang, Tina; Di Zazzo, Antonio; Nakatani, Satoru; Yamaguchi, Masahiro; Ebihara, Nobuyuki; Murakami, Akira

    2017-06-08

    The aims of this study were to investigate the incidence of positive donor tissue cultures before transfer to preservation medium (Optisol™-GS) for penetrating keratoplasty, to verify the efficacy of antibiotics contained in Optisol™-GS by examining the drug susceptibility and to assess the relationship between the results of our microbial assessments as well as donor factors and the incidence of contamination. We conducted a retrospective, cross-sectional study using Juntendo Eye Bank records for all corneal transplantations. Two hundred donor conjunctiva harvestings and storage medium (EP-II(®)) cultures were performed between July 2008 and June 2011. We analyzed the associations between donor factors (age, gender, history of cataract surgery, death-to-preservation interval, cause of death) and contamination rates using multivariate analysis by the generalized estimating equation model. We obtained positive bacterial cultures from 154 of the 200 eyes (77.0%). The isolated bacteria were indigenous, such as coagulase-negative Staphylococci, Corynebacterium sp., and methicillin-resistant Staphylococcus aureus (MRSA). There was significant resistance to levofloxacin (18 eyes, 9.0%) and gentamicin (12 eyes, 6.0%), and no vancomycin-resistant bacteria were detected. The donor factors did not correlate with the prevalence of bacterial contamination in our criteria. Pre-banking microbial assessment allows for microbial detection, bacterial susceptibility and resistance testing. This is useful for developing preservation mediums containing effective spectrum antibiotic agents for high quality control of corneal banking.

  5. Customized photorefractive keratectomy to correct high ametropia after penetrating keratoplasty: A pilot study.

    Science.gov (United States)

    De Rosa, Giuseppe; Boccia, Rosa; Santamaria, Carmine; Fabbozzi, Lorenzo; De Rosa, Luigi; Lanza, Michele

    2015-01-01

    To evaluate preliminarily the safety and efficacy of customized photorefractive keratectomy (PRK) to correct ametropia and irregular astigmatism after penetrating keratoplasty (PK). This pilot study included five eyes of five patients with a mean spherical equivalent of -5.1±1.46D (range from -2.75 to -6.50D). In all cases, ametropia and irregular astigmatism was corrected with topography-guided customized PRK. Ocular examinations with topographic analysis were performed preoperatively as well as at 1, 3 and 6 months after surgery. All eyes gained postoperatively at least three Snellen lines of uncorrected visual acuity. Mean refractive spherical equivalent was 0.62±0.63D (range from -0.25 to -1.75D) at 6 months postoperatively. Our pilot study suggests that customized PRK can be a safe and effective method for treating ametropia and irregular astigmatisms after PK. Future studies with larger samples and longer follow-ups should be performed to confirm these results. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  6. Corneal endothelial rejection after penetrating keratoplasty treated with intravenous and topic corticosteroid: one year follow up

    Directory of Open Access Journals (Sweden)

    Ricardo Yuji Abe

    2013-02-01

    Full Text Available OBJECTIVE: To analyze the recovery of visual acuity (VA and graft survival after first episode of endothelial rejection in penetrating keratoplasty (PKP treated with intravenous (IV and topic corticosteroid. METHODS: Interventional, prospective, non-comparative case series study evolving 32 PKP patients in one year follow up, who presented first episode of corneal endothelial rejection. The patients were submitted to 500 mg IV injection of methylprednisolone in association with topical prednisolone. Main outcome measures included VA recovery and corneal edema regression. Second outcome included new rejections and graft failure. Multivariate analysis techniques were used to estimate rates of graft outcome events and the impact of risk factors. RESULTS: A total of 32 eyes from 32 patients (13 male and 19 female were included in the study. The mean VA (in number of letters before rejection was 48 (22 to 88 letters. Patients treated within 7 days or less of initial symptoms had better VA recovery, corneal edema regression and less graft failure (p<0.001. Patients with previous ocular surgery had worse VA recovery and more graft failure (p<0.047. CONCLUSION: The association between the other risk factors and the outcomes did not reach statistical significance in the multivariate model because of the small numbers of patients. Methylprednisolone in association with topical prednisolone is an alternative treatment for graft rejection. Our study showed that patients treated within 7 days of symptoms and no previous anterior segment surgery had better visual outcome and graft survival after treatment.

  7. Precut cornea for Descemet's stripping endothelial keratoplasty: experience at a single eye bank.

    Science.gov (United States)

    Mohamed, Ashik; Chaurasia, Sunita; Chandragiri, Venkataswamy; Kandhibanda, Srinivas; Gunnam, Srinivas; Garg, Prashant

    2016-07-20

    The aim of the study is to describe the experience with precut facility for endothelial keratoplasty at a single eye bank affiliated to a tertiary eye care center in India. Data on precut tissues from Nov 2012 to Dec 2014 were retrospectively reviewed from the electronic database of the eye bank of a tertiary eye care center in South India. Donor characteristic data including donor age, precut and postcut endothelial cell density (ECD), recipient age, and thickness of graft were collected. The number of precuts increased from 42 in 2012 (Nov and Dec) and 422 in 2013 to 584 in 2014. Of the total of 1048 precuts, seven (0.67 %) were miscut and could not be utilized for transplants. The donor age ranged from 2 to 89 years. A mean change of 43.6 ± 325.2 cells/mm(2) in ECD was noted after cut, proportional increase in mean being 1.9 %. The change in ECD after cut was negatively correlated with ECD before cut. The recipient age ranged from 1 to 89 years. The median thickness of donor lenticule after cut was 148 µm (interquartile range 131-166 µm). Analysis of precut donor corneas from a single eye bank shows that the ECD of the processed tissues was excellent for transplantation. The tissue wastage in the hands of eye bank personal was minimal.

  8. Stimulated penetrating keratoplasty using real-time virtual intraoperative surgical optical coherence tomography

    Science.gov (United States)

    Lee, Changho; Kim, Kyungun; Han, Seunghoon; Kim, Sehui; Lee, Jun Hoon; Kim, Hong kyun; Kim, Chulhong; Jung, Woonggyu; Kim, Jeehyun

    2014-01-01

    Abstract. An intraoperative surgical microscope is an essential tool in a neuro- or ophthalmological surgical environment. Yet, it has an inherent limitation to classify subsurface information because it only provides the surface images. To compensate for and assist in this problem, combining the surgical microscope with optical coherence tomography (OCT) has been adapted. We developed a real-time virtual intraoperative surgical OCT (VISOCT) system by adapting a spectral-domain OCT scanner with a commercial surgical microscope. Thanks to our custom-made beam splitting and image display subsystems, the OCT images and microscopic images are simultaneously visualized through an ocular lens or the eyepiece of the microscope. This improvement helps surgeons to focus on the operation without distraction to view OCT images on another separate display. Moreover, displaying the OCT live images on the eyepiece helps surgeon’s depth perception during the surgeries. Finally, we successfully processed stimulated penetrating keratoplasty in live rabbits. We believe that these technical achievements are crucial to enhance the usability of the VISOCT system in a real surgical operating condition. PMID:24604471

  9. Late spontaneous resolution of a double anterior chamber post deep anterior lamellar keratoplasty

    Directory of Open Access Journals (Sweden)

    Andrea Passani

    2017-01-01

    Full Text Available A 31-year-old healthy male underwent deep anterior lamellar keratoplasty with big-bubble technique for treatment of keratoconus in his right eye. One week after surgery, he presented with detachment of the endothelium-Descemet complex with formation of a double anterior chamber, despite the apparent absence of an intraoperative Descemet membrane rupture. A subsequent intervention with the intent to relocate the corneal graft button was not effective, because the detachment appeared again one day later. The authors hypothesized that, at the time of the stromal dissection with big bubble technique, a small amount of air penetrated into the anterior chamber, creating a false pathway through the trabecular meshwork. The aqueous humor then penetrated the graft flowing through the false pathway, causing the endothelium-Descemet detachment. The persistence of that pathway, even after the intervention of graft repositioning, caused the failure of the latter procedure and persistence of the double chamber. We decided to wait and observe. The double anterior chamber spontaneously resolved in approximately three months.

  10. Delayed-Onset Post-Keratoplasty Endophthalmitis Caused by Vancomycin-Resistant Enterococcus faecium

    Directory of Open Access Journals (Sweden)

    Julio C. Hernandez-Camarena

    2012-10-01

    Full Text Available Background: Vancomycin-resistant Enterococcus (VRE endophthalmitis after penetrating keratoplasty (PKP is very rare, the management is a challenge due to both the pattern of antibiotic resistance and the aggressive nature of the infectious process. We report the first delayed-onset case of VRE endophthalmitis after PKP. Materials and Methods: Case report of a 51-year-old female with a 7-week history of PKP who arrived at the emergency room with signs and symptoms of endophthalmitis. Initial visual acuity was light perception, and a posterior pole exam was not possible due to the intense vitreous reaction. Mode B ultrasound was used to assess the posterior pole. The patient underwent pars plana vitrectomy and received intravitreous antibiotics. Results: Vitreous stains and cultures were positive for Enterococcus faecium resistant to vancomycin. Donor rim cultures and viral PCR were negative. Treatment was carried out by repeated intravitreal antibiotics and systemic linezolid. Clinical improvement was seen after the second dose of intravitreous antibiotics and systemic linezolid, but visual acuity remained at light perception consistent with the ischemic changes observed in the posterior pole. Conclusion: VRE endophthalmitis might be associated with positive donor rim cultures. Prompt use of systemic linezolid in addition to intravitreous antibiotics is recommendable, but even with prompt treatment, visual prognosis is guarded.

  11. Minimal trephination penetrating keratoplasty for severe fungal keratitis complicated with hypopyon.

    Science.gov (United States)

    Liu, Yang; Jia, Hui; Shi, Xiaoru; Wang, Jiao; Ning, Yan; He, Bing; Wang, Chunmei; Zheng, Xiaodong

    2013-12-01

    To report outcomes after minimal trephination penetrating keratoplasty (PKP) in the treatment of severe fungal keratitis complicated with hypopyon. Retrospective case series. Series of 19 eyes in 19 patients with severe fungal keratitis complicated with hypopyon that received minimal trephination PKP. The host trephination was made equal to or smaller than the margin of the corneal lesion. Fluconazole (0.2%) was used to irrigate the trephined edge and anterior chamber during surgery, followed by irrigation of the anterior chamber with a 0.02% fluconazole solution after graft transplantation. Postoperative complications, graft rejection, transparency rate, and visual acuity were recorded. Patients were followed postoperatively for 18 to 34 months (mean 28.6 months). At 18 months after PKP, 18 grafts (94.7%) remained clear and 14 eyes (73.7%) had improved visual acuity. Three eyes (15.8%) with secondary glaucoma complications after PKP were treated with subsequent trabeculectomy. Recurrent infection was found in only 1 eye (5.26%) after transplantation and was successfully managed. Immune graft rejections were not observed in any patient during the follow-up period. The minimal trephination technique in combination with antifungal therapy was effective in the treatment of severe fungal keratitis with large corneal lesions and hypopyon. Copyright © 2013 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  12. Deep anterior lamellar keratoplasty of dog eyes using the big-bubble technique

    Science.gov (United States)

    Kim, Soohyun; Kwak, Ji Yoon; Jeong, Manbok

    2016-01-01

    This study was conducted to establish the feasibility of corneal transplantation using the big-bubble technique (BBT) to perform deep anterior lamellar keratoplasty (DALK) in three dogs. After the cornea was trephined 750 µm, 4 mL of air was injected, and the blanched stroma was removed to expose Descemet's membrane (DM). The donor corneal button, which was gently stripped off the DM, was sutured onto the bare DM of the recipient cornea. The dogs received topical antibiotics every 6 h for 7 days and 2% cyclosporine ointment every 12 h for 1 month. The eyes were examined post-operatively at 7, 14, 21, 28 and 150 days. The central portion of the transplanted cornea stayed transparent while corneal haze developed around the transplanted margin. Menace response was normal even though the transplanted cornea was edematous until 3 weeks after surgery. A marginal haze was rarely observed between the donor and recipient corneas at 150 days after the operation. A spotted haze developed in the central part of the deep stroma near the DM. Upon histopathological examination, the stroma and epithelium of the donor cornea had normal structures. Corneal transplantation using DALK with BBT can be performed in dogs preserving the healthy endothelium. PMID:26645335

  13. The treatment of acute corneal hydrops by subtotal penetrating keratoplasty. Clinical case

    Directory of Open Access Journals (Sweden)

    I. A. Loskutov

    2014-07-01

    Full Text Available Clinical case of acute hydrops treatment using subtotal penetrating keratoplasty (PK is presented. The diagnosis of acute hydrops was based on clinical and functional evaluations including optical coherent tomography (OCT. A part of diseased cornea was removed and examined under a light microscope. These studies revealed morphological changes in almost all corneal layers. OCT and histology demonstrated that PK was indicated to this patient. Recent literature data on the epidemiology and pathogenesis of acute hydrops are presented. This rare disease results from tears in the Descemet’s membrane that allow aqueous humor to enter the stroma. Current treatment is aimed to suppress corneal inflammation, restore endothelium and Descemet’s membrane integrity and drain stromal cysts to optimize cornea healing. In this case, subtotal PK was performed due to the significant corneal thinning and a high risk of its melting. «Material for corneal graft» (iLab, Moscow, Russia was used as a donor material.

  14. Ahmed glaucoma valve in post-penetrating-keratoplasty glaucoma: A critically evaluated prospective clinical study

    Science.gov (United States)

    Panda, Anita; Prakash, Vadivelu Jaya; Dada, Tanuj; Gupta, Anoop Kishore; Khokhar, Sudarshan; Vanathi, Murugesan

    2011-01-01

    Aim: The aim was to evaluate the outcome of Ahmed glaucoma valve (AGV) in post-penetrating-keratoplasty glaucoma (PKPG). Materials and Methods: In this prospective study, 20 eyes of 20 adult patients with post-PKPG with intraocular pressure (IOP) >21 mmHg, on two or more antiglaucoma medications, underwent AG (model FP7) implantation and were followed up for a minimum of 6 months. Absolute success was defined as 5

  15. Ahmed glaucoma valve in post-penetrating-keratoplasty glaucoma: A critically evaluated prospective clinical study

    Directory of Open Access Journals (Sweden)

    Anita Panda

    2011-01-01

    Full Text Available Aim: The aim was to evaluate the outcome of Ahmed glaucoma valve (AGV in post-penetrating-keratoplasty glaucoma (PKPG. Materials and Methods: In this prospective study, 20 eyes of 20 adult patients with post-PKPG with intraocular pressure (IOP >21 mmHg, on two or more antiglaucoma medications, underwent AG (model FP7 implantation and were followed up for a minimum of 6 months. Absolute success was defined as 5 < IOP < 21 mmHg and qualified success as 5 < IOP < 21 mmHg with medications or minor procedures. Results: The mean IOP decreased from 42.95 ± 10.24 to 17.69 ± 3.64 mmHg (P < 0.001 and the use of medications dropped from 2.92 to 0.39 (P < 0.001 after AGV implantation. The absolute success was achieved in 11 eyes and qualified success in 9. There was no significant change in best corrected visual acuity, graft clarity, or graft thickness. Six device-related complications occurred after AGV implantations which were successfully managed with medical or minor surgical therapy. Conclusions: Postkeratoplasty refractory glaucoma managed by AGV implantation revealed a satisfactory outcome up to 6 months of follow-up.

  16. Methicillin-Resistant Staphylococcus aureus Keratitis after Descemet's Stripping Automated Endothelial Keratoplasty

    Directory of Open Access Journals (Sweden)

    Tatsuro Miyamoto

    2013-11-01

    Full Text Available Purpose: We report a case of methicillin-resistant Staphylococcus aureus (MRSA keratitis after Descemet's stripping automated endothelial keratoplasty (DSAEK. Case Report: An 87-year-old woman who had undergone a DSAEK 4 months previously was referred to Tokushima University Hospital with a diagnosis of infectious keratitis after DSAEK. A white abscess and infiltration in the inferior cornea of the right eye were observed. We started an empiric therapy using topical levofloxacin and chloramphenicol on the basis of the microscopic findings of the corneal scraping concurrently with cultivation of the cornea. Results: A strain of MRSA was isolated from the corneal sample. Although the strain was susceptible to chloramphenicol, it was resistant to quinolone. The keratitis improved rapidly due to empiric therapy, and topical steroids could be resumed 6 days after initiation of the empiric therapy. Conclusions: To our knowledge, this is the first case of MRSA keratitis, and the second case of bacterial keratitis, after DSAEK. MRSA keratitis can occur following uneventful DSAEK. The empiric therapy on the basis of results from a light microscopic examination of a Gram-stained corneal scraping and restarting topical steroids in the early stages of medication contributed to the good clinical course of this case.

  17. Weighing of risk factors for penetrating keratoplasty graft failure: application of Risk Score System

    Directory of Open Access Journals (Sweden)

    Abdo Karim Tourkmani

    2017-03-01

    Full Text Available AIM: To analyze the relationship between the score obtained in the Risk Score System (RSS proposed by Hicks et al with penetrating keratoplasty (PKP graft failure at 1y postoperatively and among each factor in the RSS with the risk of PKP graft failure using univariate and multivariate analysis. METHODS: The retrospective cohort study had 152 PKPs from 152 patients. Eighteen cases were excluded from our study due to primary failure (10 cases, incomplete medical notes (5 cases and follow-up less than 1y (3 cases. We included 134 PKPs from 134 patients stratified by preoperative risk score. Spearman coefficient was calculated for the relationship between the score obtained and risk of failure at 1y. Univariate and multivariate analysis were calculated for the impact of every single risk factor included in the RSS over graft failure at 1y. RESULTS: Spearman coefficient showed statistically significant correlation between the score in the RSS and graft failure (P0.05 between diagnosis and lens status with graft failure. The relationship between the other risk factors studied and graft failure was significant (P<0.05, although the results for previous grafts and graft failure was unreliable. None of our patients had previous blood transfusion, thus, it had no impact. CONCLUSION: After the application of multivariate analysis techniques, some risk factors do not show the expected impact over graft failure at 1y.

  18. Delayed-Onset Post-Keratoplasty Endophthalmitis Caused by Vancomycin-Resistant Enterococcus faecium

    Science.gov (United States)

    Hernandez-Camarena, Julio C.; Bautista-de Lucio, Victor M.; Navas, Alejandro; Ramirez-Miranda, Arturo; Graue-Hernandez, Enrique O.

    2012-01-01

    Background Vancomycin-resistant Enterococcus (VRE) endophthalmitis after penetrating keratoplasty (PKP) is very rare, the management is a challenge due to both the pattern of antibiotic resistance and the aggressive nature of the infectious process. We report the first delayed-onset case of VRE endophthalmitis after PKP. Materials and Methods Case report of a 51-year-old female with a 7-week history of PKP who arrived at the emergency room with signs and symptoms of endophthalmitis. Initial visual acuity was light perception, and a posterior pole exam was not possible due to the intense vitreous reaction. Mode B ultrasound was used to assess the posterior pole. The patient underwent pars plana vitrectomy and received intravitreous antibiotics. Results Vitreous stains and cultures were positive for Enterococcus faecium resistant to vancomycin. Donor rim cultures and viral PCR were negative. Treatment was carried out by repeated intravitreal antibiotics and systemic linezolid. Clinical improvement was seen after the second dose of intravitreous antibiotics and systemic linezolid, but visual acuity remained at light perception consistent with the ischemic changes observed in the posterior pole. Conclusion VRE endophthalmitis might be associated with positive donor rim cultures. Prompt use of systemic linezolid in addition to intravitreous antibiotics is recommendable, but even with prompt treatment, visual prognosis is guarded. PMID:23185179

  19. Laser Scanning In Vivo Confocal Microscopy of Clear Grafts after Penetrating Keratoplasty

    Science.gov (United States)

    Wang, Dai; Song, Peng; Wang, Shuting; Sun, Dapeng; Wang, Yuexin; Zhang, Yangyang

    2016-01-01

    Purpose. To evaluate the changes of keratocytes and dendritic cells in the central clear graft by laser scanning in vivo confocal microscopy after penetrating keratoplasty (PK). Methods. Thirty adult subjects receiving PK at Shandong Eye Institute and with clear grafts and no sign of immune rejection after surgery were recruited into this study, and 10 healthy adults were controls. The keratocytes and dendritic cells in the central graft were evaluated by laser scanning confocal microscopy, as well as epithelium cells, keratocytes, corneal endothelium cells, and corneal nerves (especially subepithelial plexus nerves). Results. Median density of subepithelial plexus nerves, keratocyte density in each layer of the stroma, and density of corneal endothelium cells were all lower in clear grafts than in controls. The dendritic cells of five (16.7%) patients were active in Bowman's membrane and stromal membrane of the graft after PK. Conclusions. Activated dendritic cells and Langerhans cells could be detected in some of the clear grafts, which indicated that the subclinical stress of immune reaction took part in the chronic injury of the clear graft after PK, even when there was no clinical rejection episode. PMID:27034940

  20. Laser Scanning In Vivo Confocal Microscopy of Clear Grafts after Penetrating Keratoplasty

    Directory of Open Access Journals (Sweden)

    Dai Wang

    2016-01-01

    Full Text Available Purpose. To evaluate the changes of keratocytes and dendritic cells in the central clear graft by laser scanning in vivo confocal microscopy after penetrating keratoplasty (PK. Methods. Thirty adult subjects receiving PK at Shandong Eye Institute and with clear grafts and no sign of immune rejection after surgery were recruited into this study, and 10 healthy adults were controls. The keratocytes and dendritic cells in the central graft were evaluated by laser scanning confocal microscopy, as well as epithelium cells, keratocytes, corneal endothelium cells, and corneal nerves (especially subepithelial plexus nerves. Results. Median density of subepithelial plexus nerves, keratocyte density in each layer of the stroma, and density of corneal endothelium cells were all lower in clear grafts than in controls. The dendritic cells of five (16.7% patients were active in Bowman’s membrane and stromal membrane of the graft after PK. Conclusions. Activated dendritic cells and Langerhans cells could be detected in some of the clear grafts, which indicated that the subclinical stress of immune reaction took part in the chronic injury of the clear graft after PK, even when there was no clinical rejection episode.

  1. Femtosecond Optical Trapping of Cells: Efficiency and Viability

    Institute of Scientific and Technical Information of China (English)

    GONG Jixian; LI Fang; XING Qirong

    2009-01-01

    The femtosecond optical trapping capability and the effect of femtosecond laser pulses on cell viability were studied. The maximum lateral velocity at which the particles just failed to be trapped, together with the measured average trapping power, were used to calculate the lateral trapping force(Q-value). The viability of the cells after femtosecond laser trapping was ascertained by vital staining. Measurement of the Q-values shows that femtosecond optical tweezers are just as effective as continuous wave optical tweezers. The experiments demonstrate that there is a critical limit for expo-sure time at each corresponding laser power of femtosecond optical tweezers, and femtosecond laser tweezers are safe for optical trapping at low power with short exposure time.

  2. 液压碳石墨密封环激光辅助车削的加工性能研究%Study on machinability for laser-assisted machining of hydraulic carbon-graphite seal rings

    Institute of Scientific and Technical Information of China (English)

    薄纪康; 张海英

    2012-01-01

    为了实现液压碳石墨密封环的高效车削加工,采用激光辅助加工方法,进行了碳石墨密封环材料的激光辅助车削加工研究.考虑到碳石墨密封环材料具有高强度、高硬度等特点,利用激光束对工件进行局部加热,以提高加工效率、减小切削力和刀具磨损.针对碳石墨M104密封环的车削加工过程,进行了常规切削和激光辅助切削的对比实验研究.设计了激光辅助加工的实验流程,并进行了工艺参量的合理选择,得到了较高的切削效率.结果表明,激光辅助切削的主切削力和径向力分别比常规切削下降了23.5%和19.9%;激光辅助切削的切削区温度分布与常规切削相近;刀具磨损和破损的程度较小,能获得较好的表面加工质量.%To perform high efficient turning of hydraulic carbon-graphite seal rings, the laser-assisted machining of the material of carbon-graphite seal ring was conducted using laser pre-heating. The material of carbon-graphite seal rings has the characteristics of high strength and high hardness, and is typical non-metallic difficult-to-machine material. The laser-assisted machining heats the workpiece using laser beam, improving machining efficiency as well as reducing cutting force and tool wear. The turning process of carbon-graphite M104 seal ring was focused on, and the conventional machining was compared with the laser-assisted machining. The experimental process of laser-assisted machining was designed and reasonable process parameters were selected. A high cutting efficiency was obtained. The main cutting force and radial force decreased by 23. 5% and 19. 9% compared with conventional machining. The temperature distribution in the cutting zone of laser-assisted machining is similar to conventional machining. The laser-assisted machining has less tool wear and can get a better surface quality.

  3. Outcomes of vitrified-warmed cleavage-stage embryo hatching after in vitro laser-assisted zona pellucida thinning in patients

    Science.gov (United States)

    Wang, En-Hua; Wang, An-Cong; Wang, Bao-Song; Li, Bin

    2016-01-01

    The aim of the present study was to determine whether the size of the zona pellucida (ZP) thinning area by laser-assisted hatching affected the potential development of vitrified-warmed embryos. A total of 196 vitrified-warmed cleavage-stage embryos (from 49 patients, four sister embryos per patient) were used in the study, i.e., four sister embryos from each patient were randomly assigned to four groups: a control group of embryos that were not zona-manipulated (zona intact, group A); one experimental group of embryos in which a quarter of the zona pellucida was thinned using laser-assisted ZP thinning (group B); a second experimental group of embryos in which half of ZP was thinned (group C); and a third group in which two-thirds of the ZP was thinned (group D). Subsequent blastocyst development was assessed. Microscopy was performed to study the hatching process of the embryos after zona thinning. The blastocyst formation rates were 71.43% in group A, 67.35% in group B, 65.31% in group C, and 51.02% in group D (groups B-D vs. group A, P=0.661, P=0.515, P=0.038, respectively). The rates of complete hatching were 30.61% in group A, 38.78% in group B, 61.22% in group C, and 48.98% in group D (groups B-D vs. group A, P=0.396, P=0.002, P=0.063, respectively). For a subgroup of patients, there was a significant difference in the complete hatching in all the groups for women aged infertility women (P=0.022). There was no significant difference in the blastocyst formation rates in the different groups of women aged ≥35 years (P=0.340). In addition, there was no significant difference in the complete hatching in the different groups among women aged ≥35 years (P=0.492). The results of the present study showed that in vitrified-warmed embryo transfers at the cleavage-stage, and the two-thirds zona pellucida thinning group demonstrated a significantly decreased blastocyst formation rate compared with the control group, while the half zona pellucida thinning group

  4. Characteristics and Applications of Spatiotemporally Focused Femtosecond Laser Pulses

    Directory of Open Access Journals (Sweden)

    Chenrui Jing

    2016-12-01

    Full Text Available Simultaneous spatial and temporal focusing (SSTF of femtosecond laser pulses gives rise to strong suppression of nonlinear self-focusing during the propagation of the femtosecond laser beam. In this paper, we begin with an introduction of the principle of SSTF, followed by a review of our recent experimental results on the characterization and application of the spatiotemporally focused pulses for femtosecond laser micromachining. Finally, we summarize all of the results and give a future perspective of this technique.

  5. Interaction of femtosecond laser pulses with metal photocathode

    Institute of Scientific and Technical Information of China (English)

    Liu Yun-Quan; Zhang Jie; Liang Wen-Xi

    2005-01-01

    The features of interaction of femtosecond laser pulses with photocathode are studied theoretically in this paper.The surface temperature of the metal cathode film while femtosecond laser pulses irradiation is studied with twotemperature model. With a simple photoelectric model we obtain the optimum metal film thickness for the backilluminated photocathode. The generated ultrashort photocurrent pulses are strongly dependent on the temperature of the electron gas and the lattice during the femtosecond laser pulse irradiation on the photocathode.

  6. Fabrication of Micro -Optical Devices by a Femtosecond Laser

    Institute of Scientific and Technical Information of China (English)

    Kazuyuki; Hirao

    2003-01-01

    Femtosecond laser is a perfect laser source for materials processing when high accuracy and small structure size are required. Due to the ultra short interaction time and the high peak power, the process is generally characterized by the absence of heat diffusion and, consequently molten layers. Various induced structures have been observed in materials after the femtosecond laser irradiation. Here, we report on fabrication of micro-optical devices by the femtosecond laser. 1) formation of optical waveg...

  7. Nonadiabatic Induced Dipole Moment by High Intensity Femtosecond Optical Pulses

    OpenAIRE

    Koprinkov, I. G.

    2006-01-01

    Nonadiabtic dressed states and nonadiabatic induced dipole moment in the leading order of nonadiabaticity is proposed. The nonadiabatic induced dipole moment is studied in the femtosecond time domain.

  8. Excimer laser "corneal shaping": a new technique for customized trephination in penetrating keratoplasty. First experimental results in rabbits.

    Science.gov (United States)

    Schmitz, Klaus; Schreiber, Wolfram; Behrens-Baumann, Wolfgang

    2003-05-01

    The aim of the presented experimental work was to develop a technique for congruent trephination of donor and recipient corneas in free form using a 193-nm excimer laser and to study the clinical follow-up after the application of the technique in a rabbit model. In 12 New Zealand White rabbits homologous penetrating keratoplasty was performed. Trephination of donor buttons and recipient beds was achieved in six animals by conventional mechanical trephination and in six by excimer laser trephination with a guided laser beam in a non-circular geometry. The surgical procedure and its applicability to human subjects were evaluated and the postoperative clinical course was followed for 6 months. The surgical procedure of full-thickness excimer laser trephination could be performed reproducibly in the animal model both for dissection of the donor buttons and for preparation of the recipient beds. Keratoplasty was performed with kidney-shaped transplants after trephination in free form with the guided laser beam. Postoperative clinical follow-up did not show any differences between the two trephination groups that could be related to the applied trephination technique. After 6 months we observed well-adapted and clear corneal grafts, kidney-shaped in the excimer trephination group and circular in the mechanical trephination group. No side effects on the crystalline lens and the central retina could be clinically observed following excimer laser trephination. We present the first experimental study of keratoplasty with freely selected transplant geometry and perfect congruence of donor button and recipient bed. The application of this technique in certain corneal disorders in humans will offer improved treatment options in the future.

  9. Cutting NiTi with Femtosecond Laser

    Directory of Open Access Journals (Sweden)

    L. Quintino

    2013-01-01

    Full Text Available Superelastic shape memory alloys are difficult to machine by thermal processes due to the facility for Ti oxidation and by mechanical processes due to their superelastic behavior. In this study, femtosecond lasers were tested to analyze the potential for machining NiTi since femtosecond lasers allow nonthermal processing of materials by ablation. The effect of processing parameters on machining depth was studied, and material removal rates were computed. Surfaces produced were analyzed under SEM which shows a resolidified thin layer with minimal heat affected zones. However, for high cutting speeds, that is, for short interaction times, this layer was not observed. A depletion of Ni was seen which may be beneficial in biomedical applications since Ni is known to produce human tissue reactions in biophysical environments.

  10. High-dispersive mirrors for femtosecond lasers.

    Science.gov (United States)

    Pervak, V; Teisset, C; Sugita, A; Naumov, S; Krausz, F; Apolonski, A

    2008-07-07

    We report on the development of highly dispersive mirrors for chirped-pulse oscillators (CPO) and amplifiers (CPA). In this proof-of-concept study, we demonstrate the usability of highly dispersive multilayer mirrors for high-energy femtosecond oscillators, namely for i) a chirped-pulse Ti:Sa oscillator and ii) an Yb:YAG disk oscillator. In both cases a group delay dispersion (GDD) of the order of 2x10(4) fs(2) was introduced, accompanied with an overall transmission loss as low as approximately 2 per cent. This unprecedented combination of high dispersion and low loss over a sizeable bandwidth with multilayer structures opens the prospects for femtosecond CPA systems equipped with a compact, alignment-insensitive all-mirror compressors providing compensation of GDD as well as higher-order dispersion.

  11. Femtosecond Timing Distribution Using Optical Pulses

    CERN Document Server

    Winter, A; Winter, A

    2005-01-01

    Fourth-generation light sources, such as the European X-ray Free Electron Laser (XFEL) require timing signals distributed over distances of several kilometers with a stability in the order of femtoseconds. A promising approach is the use of a mode-locked laser that generates sub-picosecond pulses which are distributed in timing stabilized optical fiber links. A good candidate for a laser master oscillator (LMO) is a mode-locked Erbium-doped fiber laser, featuring extremely low phase noise far from the carrier. Results on the development of the LMO locked to an external reference microwave oscillator to suppress low frequency jitter, the distribution via timing stabilized optical fiber links and the reconversion of the optical pulses to a low phase noise microwave RF signals with overall femtosecond stability are presented.

  12. Preliminary Design of a Femtosecond Oscilloscope

    CERN Document Server

    Gazazyan, Edmond D; Kalantaryan, Davit K; Laziev, Edouard; Margaryan, Amour

    2005-01-01

    The calculations on motion of electrons in a finite length electromagnetic field of linearly and circularly polarized laser beams have shown that one can use the transversal deflection of electrons on a screen at a certain distance after the interaction region for the measurement of the length and longitudinal particle distribution of femtosecond bunches. In this work the construction and preliminary parameters of various parts of a device that may be called femtosecond oscilloscope are considered. The influence of various factors, such as the energy spread and size of the electron bunches, are taken into account. For CO2 laser intensity 1016 W/cm2 and field free drift length 1m the deflection is 5.3 and 0.06 cm, while the few centimeters long interaction length between 2 mirrors requires assembling accuracy 6 mm and 1.3 micron for 20 MeV to 50 keV, respectively.

  13. Femtosecond Laser Interaction with Energetic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Roos, E; Benterou, J; Lee, R; Roeske, F; Stuart, B

    2002-03-25

    Femtosecond laser ablation shows promise in machining energetic materials into desired shapes with minimal thermal and mechanical effects to the remaining material. We will discuss the physical effects associated with machining energetic materials and assemblies containing energetic materials, based on experimental results. Interaction of ultra-short laser pulses with matter will produce high temperature plasma at high-pressure which results in the ablation of material. In the case of energetic material, which includes high explosives, propellants and pyrotechnics, this ablation process must be accomplished without coupling energy into the energetic material. Experiments were conducted in order to characterize and better understand the phenomena of femtosecond laser pulse ablation on a variety of explosives and propellants. Experimental data will be presented for laser fluence thresholds, machining rates, cutting depths and surface quality of the cuts.

  14. Recurrent progressive anterior segment fibrosis syndrome following a descemet-stripping endothelial keratoplasty in an infant with congenital aniridia

    Directory of Open Access Journals (Sweden)

    Mihir Kothari

    2014-01-01

    Full Text Available Progressive anterior segment fibrosis syndrome (ASFS, after intraocular surgery in older children (≥9 years and adults with congenital aniridia, is described in the literature. In this report, we describe an unique case of ASFS in an infant with congenital aniridia following a combined trabeculotomy-ectomy and its recurrence after a descemet stripping endothelial keratoplasty. The ophthalmologists should be well aware of this entity and warn the parents about its possibilities. Use of immunomodulators or prolonged anti-inflammatory therapy may be considered to prevent its occurrence.

  15. Femtosecond laser additive manufacturing of YSZ

    Science.gov (United States)

    Liu, Jian; Bai, Shuang

    2017-04-01

    Laser additive manufacturing (LAM) of Yttria-Stabilized Zirconia (YSZ) is investigated using femtosecond (fs) fiber lasers. Various processing conditions are studied, which leads to desired characteristics in terms of morphology, porosity, hardness, microstructural and mechanical properties of the processed components. High-density (>99%) YSZ part with refined grain and increased hardness was obtained. Microstructure features of fabricated specimens were studied with SEM, EDX, the measured micro hardness is achieved as high as 18.84 GPa.

  16. Femtosecond laser additive manufacturing of YSZ

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian; Bai, Shuang [PolarOnyx, Inc., San Jose, CA (United States)

    2017-04-15

    Laser additive manufacturing (LAM) of Yttria-Stabilized Zirconia (YSZ) is investigated using femtosecond (fs) fiber lasers. Various processing conditions are studied, which leads to desired characteristics in terms of morphology, porosity, hardness, microstructural and mechanical properties of the processed components. High-density (>99%) YSZ part with refined grain and increased hardness was obtained. Microstructure features of fabricated specimens were studied with SEM, EDX, the measured micro hardness is achieved as high as 18.84 GPa. (orig.)

  17. Optical diagnostics of femtosecond laser plasmas

    Institute of Scientific and Technical Information of China (English)

    李玉同; 张杰; 陈黎明; 夏江帆; 腾浩; 赵理曾; 林景全; 李英骏; 魏志义; 王龙; 江文勉

    2001-01-01

    Optical diagnostics of evolution of plasmas produced by ultrashort laser pulses is carried out using a femtosecond probing beam. The time sequence of plasma shadowgrams and interferograms are obtained. The filamentation instability in high_density region induces the local density modification. Large_scale toroidal magnetic fields confine plasma expansion in the transverse direction, resulting in the formation of a plasma jet. The plasma expansion along the target normal direction is found to scale as 1 2.

  18. Corneal trephination with the femtosecond laser.

    Science.gov (United States)

    Meltendorf, Christian; Schroeter, Jan; Bug, Reinhold; Kohnen, Thomas; Deller, Thomas

    2006-10-01

    To evaluate the feasibility and cut quality of corneal trephination in human donor corneal tissue with the femtosecond laser. Twelve human corneoscleral discs were inserted in an artificial anterior chamber. After corneal thickness measurement and tonometry, the cornea was mounted on a femtosecond laser (FEMTEC; 20/10 Perfect Vision, Heidelberg, Germany) through a contact lens (patient interface). Trephination was performed with diameters of 7.0, 7.5, 8.0, and 8.5 mm in 3 corneas each. The corneal button was removed from the corneoscleral disc in 2 of the 3 corneas in each case. The cut was not manipulated in the remaining corneas to enable histologic detection of possible tissue bridges. The cut edges were macroscopically and light-microscopically examined for quality. Corneal buttons and corneoscleral discs could be separated by blunt dissection in all cases. Tissue bridges were more common in thicker edematous corneas than in thinner ones. Both the macro- and microscopic examination disclosed smooth rectilinear cut margins with a perpendicular cut edge. This feasibility study shows that the femtosecond laser enables sufficient trephination of human donor corneas.

  19. Effect of laser energy, substrate film thickness and bioink viscosity on viability of endothelial cells printed by Laser-Assisted Bioprinting

    Science.gov (United States)

    Catros, Sylvain; Guillotin, Bertrand; Bačáková, Markéta; Fricain, Jean-Christophe; Guillemot, Fabien

    2011-04-01

    Biofabrication of three dimensional tissues by Laser-Assisted Bioprinting (LAB) implies to develop specific strategies for assembling the extracellular matrix (ECM) and cells. Possible strategies consist in (i) printing cells onto or in the depth of ECM layer and/or (ii) printing bioinks containing both cells and ECM-like printable biomaterial. The aim of this article was to evaluate combinatorial effects of laser pulse energy, ECM thickness and viscosity of the bioink on cell viability. A LAB workstation was used to print Ea.hy926 endothelial cells onto a quartz substrate covered with a film of ECM mimicking Matrigel™. Hence, effect of laser energy, Matrigel™ film thickness and bioink viscosity was addressed for different experimental conditions (8-24 μJ, 20-100 μm and 40-110 mPa s, respectively). Cell viability was assessed by live/dead assay performed 24 h post-printing. Results show that increasing the laser energy tends to augment the cell mortality while increasing the thickness of the Matrigel™ film and the viscosity of the bioink support cell viability. Hence, critical printing parameters influencing high cell viability have been related to the cell landing conditions and more specifically to the intensity of the cell impacts occurring at the air-ECM interface and at the ECM-glass interface.

  20. Comparison of Immediate and 2-Year Outcomes between Excimer Laser-Assisted Angioplasty with Spot Stent and Primary Stenting in Intermediate to Long Femoropopliteal Disease

    Directory of Open Access Journals (Sweden)

    Tien-Yu Wu

    2013-01-01

    Full Text Available Background. To compare the clinical outcomes between excimer laser-assisted angioplasty (ELA with spot stent (group A and primary stenting (group B in intermediate to long femoropopliteal disease. Methods. Outcomes of 105 patients totaling 119 legs treated with two different strategies were analyzed retrospectively in a prospectively maintained database. Results. Baseline characteristics were similar in both groups. Better angiographic results and lesser increase of serum C-reactive protein levels (0.60 ± 0.72 versus 2.98 ± 0.97 mg/dL, P<0.001 after the intervention were obtained in Group B. Group A had inferior 1-year outcomes due to higher rate of binary restenosis (67% versus 32%, P=0.001 and lower rate of primary patency (40% versus 58%, P=0.039. Rates of amputation-free survival, target vessel revascularization, assisted primary patency, and stent fracture at 24 months were similar in both groups (80% versus 82%, P=0.979, 65% versus 45%, P=0.11, 78% versus 80%, P=0.75 and 6.3% versus 6.8%, P=0.71, resp.. Conclusion. Greater vascular inflammation after ELA with spot stent resulted in earlier restenosis and inferior 1-year clinical outcomes than primary stenting. This benefit was lost in the primary stenting group at 2 years due to late catch-up restenosis. Active surveillance with prompt intervention was required to maintain the vessel patency.

  1. Biodegradable polymer thin film for enhancement of laser-assisted incision closure with an indocyanine-green-doped liquid albumin solder

    Science.gov (United States)

    Sorg, Brian S.; McNally-Heintzelman, Karen M.; Welch, Ashley J.

    2000-05-01

    The purpose of this study was to determine if solid material reinforcement of a liquid albumin solder coagulum could improve the cohesive strength of the solder and thus the ultimate breaking strength of the incision repair in vitro. A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green (ICG) dye was used to repair an incision in bovine aorta. The solder was coagulated with an 806 nm CW diode laser. A 50 micrometer thick poly(DL-lactic-co-glycolic acid) film was used to reinforce the solder (the controls had no reinforcement). Acute breaking strengths were measured and the data were analyzed by one-way ANOVA (P less than 0.05). Multiple comparisons of means were performed using the Newman- Keuls test. Observations of the failure modes indicated cohesive strength reinforcement of the test specimens versus the controls. At the higher laser powers used in this study (400 and 450 mW), the reinforced solder was consistently stronger than the controls. Reinforcement of liquid albumin solders in laser-assisted incision repair may have mechanical advantages in terms of acute breaking strength over conventional methods that do not reinforce the cohesive strength of the solder.

  2. Percutaneous laser-assisted thermal coronary angioplasty in native coronary arteries and saphenous vein grafts: initial results and angiographic follow-up.

    Science.gov (United States)

    Linnemeier, T J; Rothbaum, D A; Cumberland, D C; Landin, R J; Hodes, Z I; Ball, M W

    1990-01-01

    Percutaneous laser-assisted thermal coronary angioplasty was attempted in 29 vessels (27 patients): 10 left anterior descending, 2 left circumflex and 17 mid-shaft (non-anastomotic) saphenous vein grafts. Argon or YAG laser thermal energy was applied via a 1.3, 1.6 or 1.9 mm metal capped probe followed by conventional balloon angioplasty in 27 vessels and sole thermal laser therapy in two vessels. The laser probe successfully crossed 83% (24/29) of vessels and subsequent balloon dilatation increased the success rate to 93% (25/27). Perforation occurred in a vein graft resulting in one in-hospital death post repeat emergency coronary artery bypass graft surgery. Angiographic follow-up was obtained in 85% (24/28) of vessels. Angiographic restenosis ( greater than 50% reduction in lumen diameter) occurred in 27% (3/11) of native coronary arteries and 62% (8/13) of saphenous vein grafts. Therefore, despite high initial success rates, the application of laser thermal energy with small laser probes relative to vessel size, followed by conventional balloon angioplasty, does not appear to alter restenosis. Further evaluation of coronary laser systems should be continued only with catheters that are capable of creating channels closer to the size of the vessel treated.

  3. Ablation efficiency and relative thermal confinement measurements using wavelengths 1,064, 1,320, and 1,444 nm for laser-assisted lipolysis.

    Science.gov (United States)

    Youn, Jong-In; Holcomb, J David

    2013-02-01

    Laser-assisted lipolysis is routinely used for contouring the body and the neck while modifications of the technique have recently been advocated for facial contouring. In this study, wavelength-dependence measurements of laser lipolysis effect were performed using different lasers at 1,064, 1,320, and 1,444 nm wavelengths that are currently used clinically. Fresh porcine skin with fatty tissue was used for the experiments with radiant exposure of 5-8 W with the same parameters (beam diameter = 600 μm, peak power = 200 mJ, and pulse rate = 40 Hz) for 1,064, 1,320 and 1,444 nm laser wavelengths. After laser irradiation, ablation crater depth and width and tissue mass loss were measured using spectral optical coherence tomography and a micro-analytical balance, respectively. In addition, thermal temporal monitoring was performed with a thermal imaging camera placed over ex vivo porcine fat tissue; temperature changes were recorded for each wavelength. This study demonstrated greatest ablation crater depth and width and mass removal in fatty tissue at the 1,444 nm wavelength followed by, in order, 1,320 and 1,064 nm. In the evaluation of heat distribution at different wavelengths, reduced heat diffusion was observed at 1,444 nm. The ablation efficiency was found to be dependent upon wavelength, and the 1,444 nm wavelength was found to provide both the highest efficiency for fatty tissue ablation and the greatest thermal confinement.

  4. Effects of filling material and laser power on the formation of intermetallic compounds during laser-assisted friction stir butt welding of steel and aluminum alloys

    Science.gov (United States)

    Fei, Xinjiang; Jin, Xiangzhong; Peng, Nanxiang; Ye, Ying; Wu, Sigen; Dai, Houfu

    2016-11-01

    In this paper, two kinds of materials, Ni and Zn, are selected as filling material during laser-assisted friction stir butt welding of Q235 steel and 6061-T6 aluminum alloy, and their influences on the formation of intermetallic compounds on the steel/aluminum interface of the joints were first studied. SEM was used to analyze the profile of the intermetallic compound layer and the fractography of tensile fracture surfaces. In addition, EDS was applied to investigate the types of the intermetallic compounds. The results indicate that a thin iron-abundant intermetallic compound layer forms and ductile fracture mode occurs when Ni is added, but a thick aluminum-abundant intermetallic compound layer generates and brittle fracture mode occurs when Zn is added. So the tensile strength of the welds with Ni as filling material is greater than that with Zn as filling material. Besides, the effect of laser power on the formation of intermetallic compound layer when Ni is added was investigated. The preheated temperature field produced by laser beam in the cross section of workpiece was calculated, and the tensile strength of the joints at different laser powers was tested. Results show that only when suitable laser power is adopted, can suitable preheating temperature of the steel reach, then can thin intermetallic compound layer form and high tensile strength of the joints reach. Either excessive or insufficient laser power will reduce the tensile strength of the joints.

  5. Investigation of the dynamics of the Z-pinch imploding plasma for a laser-assisted discharge-produced Sn plasma EUV source

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Q; Yamada, J; Kishi, N; Watanabe, M; Okino, A; Horioka, K; Hotta, E, E-mail: zhu.q.ab@m.titech.ac.jp [Department of Energy Sciences, Tokyo Institute of Technology, Nagatsuta 4259 J2-35, Midori-ku, Yokohama 226-8502 (Japan)

    2011-04-13

    Dynamics of the imploding plasma and its relations to the 13.5 nm EUV emissions have been experimentally investigated for a laser-assisted Sn based discharge-produced plasma EUV source. The behaviours and two-dimensional electron density distributions of the EUV-emitting plasma were obtained using the time-resolved shadowgraph and Nomarski interferometric techniques. Observation of the plasma piston in the prepinch phase justified the validity of the zero-dimensional thin-shell model, from which the ion charge state of the prepinch plasma in the cathode region was estimated. The sausage (m = 0) instability that usually enhances the EUV emission was observed, with the radial electron density distribution that displays a concave shape at the crest of the plasma and a bell shape at the neck; the maximum of the electron density is located at one peak of the concave distribution at the crest instead of the neck. Intense EUV emission was produced by the Z-pinch plasma with the electron density (2.0-3.0) x 10{sup 18} cm{sup -3}. Moreover, the shock waves generated in the anode region can also produce in-band EUV emission with the intensity of 30% of that from the Z-pinch plasma.

  6. Successful Treatment of Keloid With Fractionated Carbon Dioxide (CO2) Laser and Laser-Assisted Drug Delivery of Triamcinolone Acetonide Ointment in an African-American Man.

    Science.gov (United States)

    Kraeva, Ekaterina; Ho, Derek; Jagdeo, Jared

    2017-09-01

    Keloids are fibrous growths that occur as a result of abnormal response to dermal injury. Keloids are cosmetically disfiguring and may impair function, often resulting in decreased patient quality-of-life. Treatment of keloids remains challenging, and rate of recurrence is high. We present a case of a 39-year-old African-American man (Fitzpatrick VI) with a 10-year history of keloid, who was successfully treated with eight sessions of fractionated carbon dioxide (CO2) laser immediately followed by laser-assisted drug delivery (LADD) of topical triamcinolone acetonide (TAC) ointment and review the medical literature on fractionated CO2 laser treatment of keloids. To the best of our knowledge, this is the first report of successful treatment of a keloid using combination therapy of fractionated CO2 laser and LADD with topical TAC ointment in an African-American man (Fitzpatrick VI) with excellent cosmetic results sustained at 22 months post-treatment. We believe that this combination treatment modality may be safe and efficacious for keloids in skin of color (Fitzpatrick IV-VI) and other patients. This case highlights the ability of laser surgeons to safely use fractionated CO2 lasers in patients of all skin colors. J Drugs Dermatol. 2017;16(9):925-927..

  7. Preliminary results of CO2 laser-assisted sclerectomy surgery (CLASS) in the treatment of advanced glaucoma in a Chinese population.

    Science.gov (United States)

    Yick, Doris W F; Lee, Jacky W Y; Tsang, Susanna; Yeung, Barry Y M; Yuen, Can Y F

    2016-11-01

    To evaluate the efficacy and safety of CO2 laser-assisted sclerectomy surgery (CLASS) in Chinese patients with advanced glaucoma.Patients with advanced glaucoma who were candidates for glaucoma filtration surgery were included. The intraocular pressure (IOP) and number of antiglaucoma medications were documented before surgery and at all postoperative clinic visits. All intra- and postoperative complications were documented. The primary outcome measures were the changes in IOP and medication use before and after the procedure as well as complications from the procedure. The secondary outcome measure included the CLASS success rate.Twenty patients (23 eyes) underwent CLASS between November 2014 and September 2015. Nineteen eyes had primary open-angle glaucoma, 2 eyes had primary angle-closure glaucoma, and 2 eyes had uveitic glaucoma. One patient was lost to follow-up. The mean age of subjects was 68.1 ± 11.9 years. IOP was significantly reduced at 1 day and 1 week after CLASS. At 6 months, the IOP and number of medications were significantly reduced by 19.0% and 38.2%, respectively (both P glaucoma.

  8. Cracking the perfusion code?: Laser-assisted Indocyanine Green angiography and combined laser Doppler spectrophotometry for intraoperative evaluation of tissue perfusion in autologous breast reconstruction with DIEP or ms-TRAM flaps.

    Science.gov (United States)

    Ludolph, Ingo; Arkudas, Andreas; Schmitz, Marweh; Boos, Anja M; Taeger, Christian D; Rother, Ulrich; Horch, Raymund E; Beier, Justus P

    2016-10-01

    The aim of this prospective study was to assess the correlation of flap perfusion analysis based on laser-assisted Indocyanine Green (ICG) angiography with combined laser Doppler spectrophotometry in autologous breast reconstruction using free DIEP/ms-TRAM flaps. Between February 2014 and July 2015, 35 free DIEP/ms-TRAM flaps were included in this study. Besides the clinical evaluation of flaps, intraoperative perfusion dynamics were assessed by means of laser-assisted ICG angiography and post-capillary oxygen saturation and relative haemoglobin content (rHb) using combined laser Doppler spectrophotometry. Correlation of the aforementioned parameters was analysed, as well as the impact on flap design and postoperative complications. Flap survival rate was 100%. There were no partial flap losses. In three cases, flap design was based on the angiography, contrary to clinical evaluation and spectrophotometry. The final decision on the inclusion of flap areas was based on the angiographic perfusion pattern. Angiography and spectrophotometry showed a correlation in most of the cases regarding tissue perfusion, post-capillary oxygen saturation and relative haemoglobin content. Laser-assisted ICG angiography is a useful tool for intraoperative evaluation of flap perfusion in autologous breast reconstruction with DIEP/ms-TRAM flaps, especially in decision making in cases where flap perfusion is not clearly assessable by clinical signs and exact determination of well-perfused flap margins is difficult to obtain. It provides an objective real-time analysis of flap perfusion, with high sensitivity for the detection of poorly perfused flap areas. Concerning the topographical mapping of well-perfused flap areas, laser-assisted angiography is superior to combined laser Doppler spectrophotometry.

  9. Electrospun nanofibrous SF/P(LLA-CL membrane: a potential substratum for endothelial keratoplasty

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    Chen JZ

    2015-05-01

    Full Text Available Junzhao Chen,1,* Chenxi Yan,1,* Mengyu Zhu,1,* Qinke Yao,1 Chunyi Shao,1 Wenjuan Lu,1 Jing Wang,2 Xiumei Mo,2 Ping Gu,1 Yao Fu,1 Xianqun Fan1 1Department of Ophthalmology, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 2Biomaterials and Tissue Engineering Laboratory, College of Chemistry and Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF has good biocompatibility but poor mechanical properties, while poly(L-lactic acid-co-Ɛ-caprolactone (P(LLA-CL has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty.Methods: Five scaffolds containing different SF:P(LLA-CL blended ratios (100:0, 75:25, 50:50, 25:75, 0:100 were manufactured. A human corneal endothelial (B4G12 cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test, cell proliferation (Ki-67, BrdU staining, and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction.Results: Different blended ratios of scaffolds

  10. Comparison of 20% sulfur hexafluoride with air for intraocular tamponade in Descemet membrane endothelial keratoplasty (DMEK

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    Benjamin Botsford

    Full Text Available ABSTRACT Purpose: To compare the effect of 20% sulfur hexafluoride (SF6 with that of air on graft detachment rates for intraocular tamponade in Descemet membrane endothelial keratoplasty (DMEK. Methods: Forty-two eyes of patients who underwent DMEK by a single surgeon (A.S.J. at Wilmer Eye Institute between January 2012 and 2014 were identified; 21 received air for intraocular tamponade and the next consecutive 21 received SF6. The main outcome measure was the graft detachment rate; univariate and multivariate analyses were performed. Results: The graft detachment rate was 67% in the air group and 19% in the SF6 group (p<0.05. No complete graft detachments occurred, and all partial detachments underwent intervention with injection of intraocular air. The percentages of eyes with 20/25 or better vision were not different between the groups (67% vs. 71%. Univariate analysis showed significantly higher detachment rates with air tamponade (OR, 8.50; p<0.005 and larger donor graft size (OR, 14.96; p<0.05. Multivariate analysis with gas but not graft size included showed that gas was an independent statistically significant predictor of outcome (OR, 6.65; p<0.05. When graft size was included as a covariate, gas was no longer a statistically significant predictor of detachment but maintained OR of 7.81 (p=0.063 similar to the results of univariate and multivariate analyses without graft size. Conclusion: In comparison with air, graft detachment rates for intraocular tamponade in DMEK were significantly reduced by 20% SF6.

  11. Image-guided modified deep anterior lamellar keratoplasty (DALK) corneal transplant using intraoperative optical coherence tomography

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    Tao, Yuankai K.; LaBarbera, Michael; Ehlers, Justis P.; Srivastava, Sunil K.; Dupps, William J.

    2015-03-01

    Deep anterior lamellar keratoplasty (DALK) is an alternative to full-thickness corneal transplant and has advantages including the absence of allograft rejection; shortened duration of topical corticosteroid treatment and reduced associated risk of glaucoma, cataract, or infection; and enables use of grafts with poor endothelial quality. DALK begins by performing a trephination of approximately 80% stromal thickness, as measured by pachymetry. After removal of the anterior stoma, a needle is inserted into the residual stroma to inject air or viscoelastic to dissect Descemet's membrane. These procedures are inherently difficult and intraoperative rates of Descemet's membrane perforation between 4-39% have been reported. Optical coherence tomography (OCT) provides high-resolution images of tissue microstructures in the cornea, including Descemet's membrane, and allows quantitation of corneal layer thicknesses. Here, we use crosssectional intraoperative OCT (iOCT) measurements of corneal thickness during surgery and a novel micrometeradjustable biopsy punch to precision-cut the stroma down to Descemet's membrane. Our prototype cutting tool allows us to establish a dissection plane at the corneal endothelium interface, mitigates variability in cut-depths as a result of tremor, reduces procedure complexity, and reduces complication rates. iOCT-guided modified DALK procedures were performed on 47 cadaveric porcine eyes by non-experts and achieved a perforation rate of ~5% with a mean corneal dissection time <18 minutes. The procedure was also successful performed on a human donor eye without perforation. Our data shows the potential for iOCT-guided precision anterior segment surgery without variability as a result of tremor and improvements to standard clinical care.

  12. Penetrating keratoplasty in eThekwini Health District 2011–2014

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    Monawwar Khan

    2015-03-01

    Full Text Available Background: Penetrating keratoplasty (PK – corneal transplantation or full-thickness corneal graft remains the primary sight-restoring procedure for corneal blindness. South Africa is experiencing a shortage of donor corneas, resulting in long waiting times for a corneal transplant. A corneal graft protocol has been drawn up in the eThekwini Health District to triage prospective corneal graft recipients.Aim: To describe the clinical and demographic profiles of patients on the elective corneal graft waiting list, the waiting time for PK and the scoring system prioritisation process of corneal graft allocation.Setting: All patients on the elective corneal graft waiting list in the eThekwini Health District.Methods: An observational, descriptive cross-sectional study was conducted for a 3-year period between April 2011 and March 2014.Results: A total of 104 patients were on the elective corneal graft waiting list for PK during the study period. Only 20% (n = 21 of patients received a corneal graft during the 3-year period. Amongst those that received a corneal graft, the median waiting period was 280 days (interquartile range 143–520 days. The majority of patients on the waiting list (67% were younger than 41 years of age. The commonest indication for PK was keratoconus (64%. Patients with higher pro forma scores are more likely to receive a corneal graft when a donor cornea becomes available.Conclusion: With a shortage of donor corneas, very few patients receive a corneal graft. Educational programmes are vital to increase awareness of corneal blindness and the value of corneal donations.

  13. Clinical application of TICL implantation for ametropia following deep anterior lamellar keratoplasty for keratoconus

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    Qin, Qin; Yang, Liping; He, Zifang; Huang, Zhenping

    2017-01-01

    Abstract Background: This study aimed to investigate the clinical application of phakic toric intraocular collamer lens (TICL) implantation in treating ametropia following deep anterior lamellar keratoplasty (DALK) for patients with keratoconus, especially the effectiveness and safety of high astigmatism and indications of TICL implantation after corneal transplantation. Methods: Using the self-controlled case series observation approach, 9 patients with ametropia (9 eyes) who underwent DALK surgery for keratoconus 1.5 years ago with stitches removed 3 months ago were kept under observation from May 2013 to April 2014 in Ophthalmic Center of Nanjing Drum Tower Hospital affiliated to Nanjing Medical University. TICL implantation was performed in all patients. The uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) were examined before surgery and 1 week, 6 months, 1 year, and 2 years after surgery. Corneal astigmatism, corneal thickness, anterior chamber depth, corneal endothelial cell density (ECD), and preoperative and postoperative intraocular pressures at different time points were measured. Intraoperative or postoperative complications of TICL implantation were observed, and the safety of the operation was evaluated. Results: The UCVA and BCVA in all operated eyes were better 6 months after surgery than before surgery. The spherical diopter and cylindrical diopter decreased to different degrees after surgery. Six months after surgery, the deviation of TICL axis in all operated eyes was less than 10 degrees, tending to be stable. No severe intraoperative or postoperative complication occurred. Conclusion: TICL implantation was an optional choice for ametropia correction after DALK surgery, especially in patients with high astigmatism. PMID:28225492

  14. Deep Anterior Lamellar Keratoplasty in Keratoconic Patients with versus without Vernal Keratoconjunctivitis

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    Feizi, Sepehr; Javadi, Mohammad Ali; Javadi, Fatemeh; Jafarinasab, Mohammad Reza

    2015-01-01

    Purpose: To compare the clinical outcomes of deep anterior lamellar keratoplasty (DALK) for keratoconus in patients with vernal keratoconjunctivitis (VKC) versus those without VKC. Methods: In this retrospective comparative study, records of 262 eyes with keratoconus (Group 1) and 28 keratoconic eyes with VKC (Group 2) that had undergone DALK were compiled. Reviewed parameters included length of follow-up, best-corrected visual acuity (BCVA), refractive error, complications and cumulative graft survival. Results: Mean duration of follow-up was 38.6 ± 20.2 and 34.4 ± 20.9 months in groups 1 and 2, respectively (P = 0.21). Mean post-operative BCVA was 0.19 ± 0.11 and 0.20 ± 0.15 logMAR, in groups 1 and 2 (P = 0.79). BCVA≥20/40 was achieved in 91.6 and 88.5% of eyes in groups 1 and 2, respectively (P = 0.48). Epithelial problems were encountered in 31.3 and 42.9% of operated eyes, respectively (P = 0.16). Vascularization of suture tracts and stitch abscesses were encountered more frequently in the eyes with VKC (P = 0.01 and <0.001, respectively). At the 33-month follow-up examination, rejection-free graft survival rates were 56.0% in group 1 and 33.3% in group 2, with mean durations of 41.0 and 32.1 months, respectively (P = 0.15). Graft survival rates were 98.1% in group 1 and 95.0% in group 2, with mean durations of 88.6 and 88.4 months, respectively (P = 0.74). Conclusion: Clinical outcomes of DALK in keratoconic eyes with VKC were comparable to those in eyes with keratoconus alone. However, complications such as suture tract vascularization and stitch abscesses were more common when VKC coexisted, necessitating closer monitoring. PMID:26425311

  15. Safety of prophylactic intracameral moxifloxacin ophthalmic solution after cataract surgery in patients with penetrating keratoplasty

    Institute of Scientific and Technical Information of China (English)

    Osman; Sevki; Arslan; Ceyhun; Arici; Mustafa; Unal; Erdogan; Cicik; Mehmet; Serhat; Mangan; Eray; Atalay

    2014-01-01

    AIM:To determine the safety of prophylactic intracameral moxifloxacin after cataract surgery in patients with penetrating keratoplasty(PKP).METHODS:In this retrospective study of consecutive patients who had phacoemulsification cataract surgery after PKP, were treated with intracameral moxifloxacin0.5% ophthalmic solution(0.5 mg/0.1 mL). The main outcome measures were anterior chamber reaction, best corrected visual acuity(BCVA), corneal endothelial cell count(ECC), and central corneal thickness(CCT).RESULTS:Fifty-five patients were recruited(26 males,29 females). The mean age was 54.36±4.97y(range 45-64y).All eyes had improved postoperative BCVA. The mean BCVA was 0.25 preoperatively and 0.57 postoperatively,which was statistically significant(P <0.001). One eye had 3+, 7 eyes had 2+, 12 eyes had 1+ and 8 eyes had trace amount of aqueous cells on the first day after surgery. All eyes had no anterior chamber cells at subsequent follow up examinations. Effective phacoemulsification time was 4.33 ±1.01 s. The mean ECC was 2340.20 cells/mm2 preoperatively and 1948.75 cells/mm21 mo postoperatively(P <0.001). The increase of21.09 μm in postoperative pachymetry 1mo after surgery was statistically significant(P <0.001).CONCLUSION:Nountowardeffectswereobservedafter intracameral injection of moxifloxacin(0.5 mg/0.1 mL) in terms of anterior chamber reaction, CCT, ECC, and visual rehabilitation at the conclusion of cataract surgery in patients with PKP.

  16. Standardization of the Descemet membrane endothelial keratoplasty technique: Outcomes of the first 450 consecutive cases.

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    Satué, M; Rodríguez-Calvo-de-Mora, M; Naveiras, M; Cabrerizo, J; Dapena, I; Melles, G R J

    2015-08-01

    To evaluate the clinical outcome of the first 450 consecutive cases after Descemet membrane endothelial keratoplasty (DMEK), as well as the effect of standardization of the technique. Comparison between 3 groups: Group I: (cases 1-125), as the extended learning curve; Group II: (cases 126-250), transition to technique standardization; Group III: (cases 251-450), surgery with standardized technique. Best corrected visual acuity, endothelial cell density, pachymetry and intra- and postoperative complications were evaluated before, and 1, 3 and 6 months after DMEK. At 6 months after surgery, 79% of eyes reached a best corrected visual acuity of≥0.8 and 43%≥1.0. Mean preoperative endothelial cell density was 2,530±220 cells/mm2 and 1,613±495 at 6 months after surgery. Mean pachymetry measured 668±92 μm and 526±46 μm pre- and (6 months) postoperatively, respectively. There were no significant differences in best corrected visual acuity, endothelial cell density and pachymetry between the 3 groups (P > .05). Graft detachment presented in 17.3% of the eyes. The detachment rate declined from 24% to 12%, and the rate of secondary surgeries from 9.6% to 3.5%, from group I to III respectively. Visual outcomes and endothelial cell density after DMEK are independent of the technique standardization. However, technique standardization may have contributed to a lower graft detachment rate and a relatively low number of secondary interventions required. As such, DMEK may become the first choice of treatment in corneal endothelial disease. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  17. Complications and management in Descemet′s stripping endothelial keratoplasty: Analysis of consecutive 430 cases

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    Samar K Basak

    2014-01-01

    Full Text Available Purpose: To analyze the complications and their managements in Descemet′s stripping endothelial keratoplasty (DSEK in consecutive 430 cases by single surgeon in a tertiary eye hospital. Materials and Methods: 430 eyes of 366 patients with endothelial dysfunctions scheduled for DSEK, were analyzed retrospectively. In all cases donor dissection was performed manually, and ′Taco′ insertion and unfolding technique was used. Intra-operative and postoperative complications with their managements and outcomes were reviewed retrospectively. Periodic endothelial cell density was analyzed for each patient till the last visit. Follow-up period was between 3 to 60 months (mean 18.7 months. Results: 13 (3.0% eyes had operative complications during donor dissection and 16 (3.7% had during recipient procedure. In 7 (1.6% eyes, donor lenticule was replaced with a new one during the surgery. In early postoperative period, 21 (4.9% eyes had donor dislocation and 12 (2.8% eyes had air-induced pupillary block; and they were managed immediately. 2 cases had primary graft failure and in 1 case had postoperative bacterial endophthalmitis requiring evisceration. In late postoperative period, 48 (11.3% eyes had secondary glaucoma and 14 (3.3% eyes had late secondary graft failure. Endothelial rejection occurred in 5 (1.2% cases. Mean endothelial cell loss was 19.7% after 3 months and 54.2% after 5 years. Total graft failure in this series was 31 (7.2% and in 17 cases re-DSEK was performed successfully. Conclusions: Both operative and postoperative complications do occur in DSEK. Most of these complications can be managed by medical or appropriate surgical means. Some of the complications can be avoided and reduced with experience.

  18. 飞秒激光白内障围手术期的护理%Perioperative Nursing of Patients with Femtosecond Laser Cataract

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    袁凤

    2016-01-01

    白内障(cataract)是发生在眼球里面晶状体上的一种疾病,任何晶状体的浑浊都可称为白内障,但是当晶状体浑浊较轻时,没有明显的影响视力而不被人发现或被忽略而没有列入白内障行列。根据调查,白内障是最常见的致盲和视力残疾的原因,其手术方式经历了巨大的变革,新近发展的飞秒激光技术-一种以超短脉冲形式运转的激光,其具备瞬时功率大,聚焦尺寸小,穿透性强,精密度高的优势。飞秒激光辅助下白内障手术(FSL-assisted cataract)在临床广泛运用。%Cataract (cataract) is in the eye of the lens of a disease, any lens turbidity can be said for cataract, but when the lens opacity is light, there is no obvious influence on visual acuity and not be found or is ignored and not included in the ranks of the cataract. According to the survey, cataract is the most common of blindness and visual disability reason, the operation mode, the experienced great changes, recent development of femtosecond laser technology---a ultrashort pulse operation of the laser, it has large instantaneous power and small focus size, strong penetrability, the advantage of high precision. Femtosecond laser assisted white Cataract surgery (FSL-assisted cataract) is widely used in clinic.

  19. MMSC-LIKE LIMBAL CELLS COTRANSPLANTATION PROMOTES LOCAL IMMUNOCORRECTION AND CORNEAL GRAFT TRANSPARENT RETENTION IN HIGH RISK KERATOPLASTY

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    S. A. Borzenok

    2014-01-01

    Full Text Available Aim was to evaluate clinical results of donor corneal graft survival in high-risk recipients in co-transplantation of preserved allogenic limbal grafts. Materials and methods. Two types of penetrative keratoplasties were carried out in patients with corneal graft opacities and high risk of rejection (n = 69. Co-transplantation of donor cornea and allogenic MMSC-like limbal cells in the form of limbal transplants was carried out in the 1st group (n = 36; in the 2nd group (n = 33 only the cornea was transplanted. Results. Observation of the patients during one year after surgery showed that the rate of transparent cornea engraftment increased in the 1st group (86,1 against 69,7% in the 2nd group. The density of endothelial cells was also higher in the 1st group (85,9 against 76,2% in the 2nd group. At the same time, progressive decreasing of pro-inflammatory cytokines (IL-6, IFNγ, TNFα and increasing of anti-inflammatory cytokines (IL-10, IL-1RA, TGFβ along with higher level of HLA-G5 were revealed in the recipients’ tear fluid in the 1st group in comparison to the 2nd group. Conclusion. Simultaneous transplantation of preserved limbal grafts with corneal graft in high-risk keratoplasty favors the transparent cornea engraftment, obviously, this is due to immunoregulatory activity of the MMSC-like limbal cells. 

  20. Two cases of ultrathin Descemet stripping automated endothelial keratoplasty utilizing a graft that had undergone radial keratotomy

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    Nahum, Yoav; Ponzin, Diego; Busin, Massimo

    2016-01-01

    This is a report of two cases in which tissue that had undergone radial keratotomy (RK) was utilized for double-pass ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK). Postoperative slit-lamp examination, visual acuity, anterior segment optical coherence tomography, and specular microscopy were available 30 months after surgery. Both corneas from a donor, who had undergone RK several years before his demise, and were otherwise suitable for endothelial keratoplasty were prepared for UT-DSAEK using double-pass dissection using first a 300 mm microkeratome head and then a 130μm microkeratome head (ALTK system, Moria, Antony, France). After the second cut, the tissue was punched to 9.0 mm and transplanted in two eyes with endothelial decompensation according to standard technique. As early as 3 months after surgery, both patients had 20/25 best-corrected visual acuity, which remained stable for the following 27 months. Postoperative endothelial cell loss was 34% and 57% at 2.5 years. In conclusion, post-RK donor tissue can be used for UT-DSAEK. PMID:27050357