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Sample records for fetoscopic laser photocoagulation

  1. Recurrent twin-twin transfusion syndrome after selective fetoscopic laser photocoagulation: a systematic review of the literature.

    Walsh, C A

    2012-11-01

    Selective fetoscopic laser photocoagulation (SFLP) is now the treatment of choice for twin-twin transfusion syndrome (TTTS). The incidence of recurrent TTTS following SFLP has been inconsistently reported across different studies. We performed a systematic review of TTTS recurrence following SFLP.

  2. Survival Rate without Brain Abnormalities on Postnatal Ultrasonography among Monochorionic Twins after Fetoscopic Laser Photocoagulation for Selective Intrauterine Growth Restriction with Concomitant Oligohydramnios.

    Ishii, Keisuke; Wada, Seiji; Takano, Mayumi; Nakata, Masahiko; Murakoshi, Takeshi; Sago, Haruhiko

    2018-02-20

    We aimed to clarify the survival rate without brain abnormalities (BA) after fetoscopic laser photoco-agulation (FLP) for monochorionic diamniotic twin gestations (MCDA) with selective intrauterine growth restriction (sIUGR) accompanied by abnormal umbilical artery (UA) Doppler waveforms and isolated oligohydramnios in the sIUGR twin. This retrospective study included 52 cases that underwent FLP. The main outcome was survival rate without BA of the twins at age 28 days. BA was defined as severe intraventricular hemorrhage and periventricular leukomalacia on postnatal ultrasonography. Median gestational age at FLP was 20 (16-24) weeks. Ten cases were classified as type III based on Doppler for the UA. For all cases, including 20 cases of anterior placenta, FLP was completed without major intraoperative complications. Amnioinfusion was required in 49 cases for better fetoscopic visualization. Fetal loss occurred in 29 sIUGR twins and two larger twins, whereas one larger twin experienced neonatal death. Survival rates without BA were 44% (n = 23) for sIUGR twins and 94% (n = 49) for the larger twins. FLP for MCDA with sIUGR presenting with oligohydramnios in the sIUGR twin might be considered a prenatal treatment option. © 2018 S. Karger AG, Basel.

  3. 'A problem shared is a problem halved': success of a statewide collaborative approach to fetal therapy. Outcomes of fetoscopic laser photocoagulation for twin-twin transfusion syndrome in Victoria.

    Teoh, Mark; Walker, Sue; Cole, Stephen; Edwards, Andrew

    2013-04-01

    To evaluate the performance of a collaborative fetal therapy service for treatment for twin-twin transfusion syndrome (TTTS). The Victorian Fetal Therapy Service (VFTS) was developed in 2006. It is a state-based three-centre collaborative service comprising a surgical team and clinical leadership group, designed to optimise access to, and performance of, fetoscopic procedures in Victoria. This is a prospective cohort study of VFTS patients referred for fetoscopic laser photocoagulation (FLP) for TTTS since 2006. Forty-nine consecutive women with advanced (stage 2-4) TTTS between 2006 and 2011 were included in this study. Overall survival was 67 of 98 (68%), and survival of ≥1 twin was seen in 42 of 49 pregnancies (86%). There was no difference in survival by disease stage at diagnosis (≥1 survivor: 66% (stage 2 or 3 TTTS) vs 77% (stage 4 TTTS), P = 0.44), nor by surgical era (≥1 survivor: 60% (2006-2008) vs 74% of cases (2009-2011), P = 0.21). The median gestation gained post-FLP was 10.5 weeks. These results are consistent with published series and confirm the success of a novel service delivery model for fetal therapy in Victoria. We suggest that collaborative models such as ours should be considered for fetal conditions where treatment is complex and the total number of cases is small to ensure a consistent approach to assessment, management and follow-up of patients and to optimise training and research opportunities. © 2013 The Authors ANZJOG © 2013 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  4. Laser photocoagulation for retinal vein occlusion

    K. A. Mirzabekova

    2015-03-01

    Full Text Available Retinal vein occlusion (RVO is one of the leading causes of permanent vision loss. In adults, central retinal vein occlusion (CRVO occurs in 1.8% while branch retinal vein occlusion (BRVO occurs in 0.2%. Treatment strategy and disease prognosis are determined by RVO type (ischemic/non-ischemic. Despite numerous studies and many current CRVO and BRVO treatment approaches, the management of these patients is still being debated. Intravitreal injections of steroids (triamcinolone acetate, dexamethasone and vascular endothelial growth factor (VEGF inhibitors (bevacizumab, ranibizumab were shown to be fairly effective. However, it is unclear whether anti-VEGF agents are reasonable in ischemic RVOs. Laser photocoagulation remains the only effective treatment of optic nerve head and/or retinal neovascularization. Laser photocoagulation is also indicated for the treatment of macular edema. Both threshold and sub-threshold photocoagulation may be performed. Photocoagulation performed with argon (514 nm, krypton (647 nm, or diode (810 nm laser for macular edema provides similar results (no significant differences. The treatment may be complex and include medication therapy and/or surgery. Medication therapy includes anti-aggregant agents and antioxidants, i.e., emoxypine which may be used in acute RVO as well as in post-thrombotic retinopathy. 

  5. Laser photocoagulation for retinal vein occlusion

    K. A. Mirzabekova

    2015-01-01

    Full Text Available Retinal vein occlusion (RVO is one of the leading causes of permanent vision loss. In adults, central retinal vein occlusion (CRVO occurs in 1.8% while branch retinal vein occlusion (BRVO occurs in 0.2%. Treatment strategy and disease prognosis are determined by RVO type (ischemic/non-ischemic. Despite numerous studies and many current CRVO and BRVO treatment approaches, the management of these patients is still being debated. Intravitreal injections of steroids (triamcinolone acetate, dexamethasone and vascular endothelial growth factor (VEGF inhibitors (bevacizumab, ranibizumab were shown to be fairly effective. However, it is unclear whether anti-VEGF agents are reasonable in ischemic RVOs. Laser photocoagulation remains the only effective treatment of optic nerve head and/or retinal neovascularization. Laser photocoagulation is also indicated for the treatment of macular edema. Both threshold and sub-threshold photocoagulation may be performed. Photocoagulation performed with argon (514 nm, krypton (647 nm, or diode (810 nm laser for macular edema provides similar results (no significant differences. The treatment may be complex and include medication therapy and/or surgery. Medication therapy includes anti-aggregant agents and antioxidants, i.e., emoxypine which may be used in acute RVO as well as in post-thrombotic retinopathy. 

  6. Laser distance measurement using a newly developed composite-type optical fiberscope for fetoscopic laser surgery

    Seki, Takeshi; Oka, Kiyoshi; Naganawa, Akihiro; Yamashita, Hiromasa; Kim, Keri; Chiba, Toshio

    2010-10-01

    Twin-twin transfusion syndrome (TTTS) is a condition of twins disproportionately sharing blood by the communicating vessels in the shared placenta and resulting in the significantly high fetal and perinatal mortality rate. Fetoscopic laser surgery is performed to block these communicating vessels. It is difficult, however, to perceive the distance from the tip of the fetoscope to the placental surface with only a two-dimensional fetoscopic view. When the distance is too short it causes excessive irradiation and even the risk of inadvertent damage to the placenta. On the other hand, not only target vessels but also adjacent tissues can be irradiated when it is too long. We have developed a composite-type optical fiberscope (COF) that was able to observe the target area and also to perform laser irradiation at the same time. In this paper, we studied a method to estimate the distance from the tip of the COF to the target area. We combined the COF with a laser blood-flow meter. Using laser light from the meter, we measured the total amount of light received ("REFLEX") and estimated the relation between the "REFLEX" value and the laser irradiation distance. Further in vivo experiments were subsequently carried out using porcine mesenteric blood vessels. The results showed that the distance and the "REFLEX" value were inversely proportional, irrespective of the experimental environment (e.g. in air, water and amniotic fluid-like solution) and the target object. In the in vivo experiments, we quantitatively measured the distance within an accuracy of ±1 mm (approximately 10%). In conclusion, our new system was able to measure the distance in vivo enabling a surgeon to safely and effectively perform laser irradiation at a suitable distance. The system can be used not only for fetoscopic surgery but also for general endoscopic surgery.

  7. Krypton red laser photocoagulation of the ocular fundus. 1982.

    Yannuzzi, Lawrence A; Shakin, Jeffrey L

    2012-02-01

    The theoretical rationale, the histopathologic evidence, and the preliminary clinical studies related to krypton red laser (KRL) photocoagulation of the ocular fundus are reviewed. The authors report on their experience with currently available laser systems using this wavelength (647.1 nm) for photocoagulation of retinal vascular proliferative diseases and chorioretinal diseases associated with exudative manifestations. A histopathologic and clinical comparison of argon blue-green laser (ABGL), the pure argon green laser (AGL), and the krypton yellow laser (KYL), with reference to photocoagulation treatment of the ocular fundus is also discussed.

  8. [SOPHOCLE (Ophthalmologic Simulator of Laser PHOtocoagulation): contribution to virtual reality].

    Rouland, J F; Dubois, P; Chaillou, C; Meseuree, P; Karpf, S; Godin, S; Duquenoy, F

    1995-01-01

    This study was undertaken to teach laser retinal photocoagulation in different disorders using a "virtual eye". Most ophthalmologists routinely use laser photocoagulator. Both indications and laser effects are well-known. However, in various diseases (diabetic retinopathy, age-related-macular degeneration, myopia...) complications rate increase or at least does not decrease. The main reasons are: - ignorance of risk factors, - misuse of the instrument. We developed a new automated device stimulating a real laser photocoagulator. Only slit-lamp exists. The three-mirror lens, the fundus and the retinal photocoagulation impacts are "virtual". The aim of the simulator is to help practitioners to recognize various pathologies almost as in real conditions and to be familiar with different technics of photocoagulation. By using computer assisted learning, a constant evaluation determines the level and the progress of practitioners.

  9. Successful fetoscopic laser coagulation for twin-to-twin transfusion syndrome under local anaesthesia.

    Cooley, S

    2011-06-01

    A review of the efficacy and outcome of fifteen fetoscopic laser ablations under local anaesthesia for twin to twin transfusion syndrome (TTTS) in the National Maternity Hospital Dublin was undertaken. The mean gestation at laser was 19.7 weeks (range 16-25 weeks) with a mean gestation at delivery of 29.1 weeks (range 20-35 weeks). The overall liveborn birth rate was 79% (22 infants) and one pregnancy was still ongoing. There were four neonatal deaths secondary to complications of prematurity. The surviving eighteen infants (64%) undergo regular paediatric review. The procedure was performed successfully in all cases with local anaesthesia. In no case was there maternal discomfort that warranted the procedure to be abandoned and good visual access of the vascular anastamoses was obtained in all cases. Local anaesthesia therefore offers a safe effective anaesthetic option for fetoscopic laser coagulation in monochorionic pregnancies complicated by TTTS.

  10. Laser photocoagulation in the palliation of colorectal malignancies

    Mathus-Vliegen, E. M.; Tytgat, G. N.

    1986-01-01

    Besides surgical intervention, there are virtually no palliative treatment modalities available for bleeding and/or obstructing colorectal malignancy. The usefulness and safety of laser photocoagulation was prospectively investigated in 63 patients with colorectal cancer. The merits were evaluated

  11. Argon laser photocoagulation of cyclodialysis clefts after cataract surgery

    Bauer, B. [Univ. of Lund, Dept. of Ophthalmology, Lund (Sweden)

    1995-06-01

    Three patients with cyclodialysis clefts, hypotony and hypotonic retinopathy subsequent to cataract surgery were treated with argon laser photocoagulation. The hypotony was reversed in each patient and their visual acuity was normalized. Laser photocoagulation is a noninvasive treatment that can be repeated easily and safely. The complications of the treatment are minor. A hypertensive episode commonly occurs in the early postoperative period. (au) 8 refs.

  12. Visual Outcome after Laser Photocoagulation for Stage 4 ...

    Objective: The objectives of this research is to evaluate the visual outcome after peripheral laser photo-coagulation for Goldberg stage-4 proliferative sickle cell retinopathy patients seen in Eye Foundation Hospital Lagos between January and December 2002. Methodology: A hospital-based retrospective case review study ...

  13. Photocoagulation of disciform macular lesions with krypton laser.

    Bird, A C; Grey, R H

    1979-01-01

    Ten vascular disciform mucular lesions were treated by krypton laser photocoagulation. In 8 the lesion resolved after therapy, and in 7 the retina remained flat for 6 months. On those patients treated successfully 6 had a visual acuity of 6/12 or better. The morphology of the laser lesion differed from that of the argon lesion in that there is no evidence of thermal coagulation of the inner retina near the foveola. Images PMID:574396

  14. Dye-enhanced diode laser photocoagulation of choroidal neovascularizations

    Klingbeil, Ulrich; Puliafito, Carmen A.; McCarthy, Dan; Reichel, Elias; Olk, Joseph; Lesiecki, Michael L.

    1994-06-01

    Dye-enhanced diode laser photocoagulation, using the dye indocyanine green (ICG), has shown some potential in the treatment of choroidal neovascularizations (CNV). A diode laser system was developed and optimized to emit at the absorption maximum of ICG. In a clinical study at two retinal centers, more than 70 patients, the majority of which had age-related macular degeneration, were treated. Eighteen cases with ill-defined subfoveal CNV were followed an average of 11 months after laser treatment. The results show success in resolving the CNV with an average long-term preservation of visual function equal to or superior to data provided by the Macular Photocoagulation Study for confluent burns of low intensity applied to the CNV. Details of the technique and discussion of the controversies inherent in such a treatment strategy will be presented.

  15. Experimental transconjunctival diode laser retinal photocoagulation through silicone scleral exoplants.

    Nanda, S K; Han, D P

    1995-07-01

    To study the feasibility of inducing a chorioretinal lesion under a previously placed scleral buckle by experimental transconjunctival diode laser photocoagulation. We performed transconjunctival diode laser photocoagulation in the peripheral retinas of seven pigmented rabbit eyes with a silicone exoplant (No. 42 band or No. 276 tire) and seven eyes without an exoplant. Each eye received burns with an intensity of grades 1 to 3 in different quadrants at varying power levels, with a 0.5-second duration and 650-micron spot size. Eyes were enucleated for histopathologic studies 1 day and 1 week after treatment. Although the irradiance emitted through the No. 42 band and the No. 276 tire was attenuated by 17% and 23%, respectively, the range of threshold powers needed to produce grades 1 to 3 burns was similar between eyes with and without a silicone exoplant. At 1 day, full-thickness coagulative necrosis was observed in all lesions, except that the ganglion cell layer and inner nuclear layer were preserved in two of four grade 1 burns and the ganglion cell layer was intact in one of six grade 2 burns. Inner scleral changes were noted acutely in three of five grade 3 lesions. At 1 week, burns of all intensity grades showed a full-thickness atrophic chorioretinal lesion with inner scleral changes. Experimental transconjunctival diode laser photocoagulation through hard silicone elements reproducibly created a chorioretinal lesion with histopathologic findings similar to those of lesions obtained without these elements. Although retinal photocoagulative effects were prominent, inner scleral abnormalities were also observed histologically.

  16. Operator competence in fetoscopic laser surgery for twin-twin transfusion syndrome: validation of a procedure-specific evaluation tool.

    Peeters, S H P; Akkermans, J; Bustraan, J; Middeldorp, J M; Lopriore, E; Devlieger, R; Lewi, L; Deprest, J; Oepkes, D

    2016-03-01

    Fetoscopic laser surgery for twin-twin transfusion syndrome is a procedure for which no objective tools exist to assess technical skills. To ensure that future fetal surgeons reach competence prior to performing the procedure unsupervised, we developed a performance assessment tool. The aim of this study was to validate this assessment tool for reliability and construct validity. We made use of a procedure-specific evaluation instrument containing all essential steps of the fetoscopic laser procedure, which was previously created using Delphi methodology. Eleven experts and 13 novices from three fetal medicine centers performed the procedure on the same simulator. Two independent observers assessed each surgery using the instrument (maximum score: 52). Interobserver reliability was assessed using Spearman correlation. We compared the performance of novices and experts to assess construct validity. The interobserver reliability was high (Rs  = 0.974, P performed by experts and in 9/13 (69%) procedures performed by novices (P = 0.005). Multivariable analysis showed that the checklist score, independent of age and gender, predicted competence. The procedure-specific assessment tool for fetoscopic laser surgery shows good interobserver reliability and discriminates experts from novices. This instrument may therefore be a useful tool in the training curriculum for fetal surgeons. Further intervention studies with reassessment before and after training may increase the construct validity of the tool. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

  17. Risk Factors Associated with Preterm Delivery after Fetoscopic Laser Surgery for Twin Twin Transfusion Syndrome

    PAPANNA, Ramesha; BLOCK-ABRAHAM, Dana; Mann, Lovepreet K; BUHIMSCHI, Irina A.; BEBBINGTON, Michael; GARCIA, Elisa; KAHLEK, Nahla; HARMAN, Christopher; JOHNSON, Anthony; BASCHAT, Ahmet; MOISE, Kenneth J.

    2014-01-01

    OBJECTIVE Despite improved perinatal survival following fetoscopic laser surgery (FLS) for twin twin transfusion syndrome (TTTS), prematurity remains an important contributor to perinatal mortality and morbidity. The objective of the study was to identify risk factors for complicated preterm delivery after FLS. STUDY DESIGN Retrospective cohort study of prospectively collected data on maternal/fetal demographics and pre-operative, operative and post-operative variables of 459 patients treated in 3 U.S. fetal centers. Multivariate linear regression was performed to identify significant risk factors associated with preterm delivery, which was cross-validated using K-fold method. Multivariate logistic regression was performed to identify risk factors for early vs. late preterm delivery based on median gestational age at delivery of 32 weeks. RESULTS There were significant differences in case selection and outcomes between the centers. After controlling for the center of surgery, a multivariate analysis indicated a lower maternal age at procedure, history of previous prematurity, shortened cervical length, use of amnioinfusion, 12 Fr cannula diameter, lack of a collagen plug placement and iatrogenic preterm premature rupture of membranes (iPPROM) were significantly associated with a lower gestational age at delivery. CONCLUSION Specific fetal/maternal and operative variables are associated with preterm delivery after FLS for the treatment of TTTS. Further studies to modify some of these variables may decrease the perinatal morbidity after laser therapy. PMID:24013922

  18. Combination of Intravitreal Ranibizumab and Laser Photocoagulation for Aggressive Posterior Retinopathy of Prematurity

    Ágata Mota

    2012-04-01

    Full Text Available Purpose: To report on 2 cases of aggressive posterior retinopathy of prematurity (ROP treated with intravitreal ranibizumab (Lucentis® and laser photocoagulation. Methods: Two premature females, born at 25 and 26 weeks’ gestation with a birth weight of 530 and 550 g, respectively, with aggressive posterior ROP received combined treatment with laser photocoagulation and intravitreal ranibizumab (0.3 mg [30 µl] to each eye. Structural outcomes were evaluated by indirect ophthalmoscopy and documented by retinography. Results: An intravitreal injection was made at 34 weeks of postmenstrual age in the first case, followed by laser photocoagulation 1 week later. There was a partial regression of ROP with treatment. Five weeks later, neovascularization regrowth with bleeding in both eyes (intraretinal and subhyaloid occurred and retreatment with combined therapy was performed. In the second case, single therapy with laser photocoagulation was made at 34 weeks of postmenstrual age. In spite of the confluent photocoagulation in the avascular area, progression to 4A ROP stage occurred 1 week later. Both eyes were retreated 1 week later with intravitreal ranibizumab and laser photocoagulation. Treatment resulted in ROP regression in both cases. There were no signs of systemic or ocular adverse side effects. Conclusion: The cases presented show that combination therapy of indirect laser photocoagulation and intravitreal ranibizumab can be effective in the management of aggressive posterior ROP. Further investigation on anti-VEGF safety in premature infants is necessary . Additional studies are needed to define the role of anti-VEGF in ROP treatment.

  19. Dynamics of pulsed holmium:YAG laser photocoagulation of albumen

    Pfefer, T.J.; Welch, A.J.

    2000-01-01

    The pulsed holmium:YAG laser (λ = 2.12 μm, τ p = 250 μs) has been investigated as a method for inducing localized coagulation for medical procedures, yet the dynamics of this process are not well understood. In this study, photocoagulation of albumen (egg white) was analysed experimentally and results compared with optical-thermal simulations to investigate a rate process approach to thermal damage and the role of heat conduction and dynamic changes in absorption. The coagulation threshold was determined using probit analysis, and coagulum dynamics were documented with fast flash photography. The nonlinear computational model, which included a Beer's law optical component, a finite difference heat transfer component and an Arrhenius equation-based damage calculation, was verified against data from the literature. Moderate discrepancies between simulation results and our experimental data probably resulted from the use of a laser beam with an irregular spatial profile. This profile produced a lower than expected coagulation threshold and an irregular damage distribution within a millisecond after laser onset. After 1 ms, heat conduction led to smoothing of the coagulum. Simulations indicated that dynamic changes in absorption led to a reduction in surface temperatures. The Arrhenius equation was shown to be effective for simulating transient albumen coagulation during pulsed holmium:YAG laser irradiation. Greater understanding of pulsed laser-tissue interactions may lead to improved treatment outcome and optimization of laser parameters for a variety of medical procedures. (author)

  20. Does anemia-polycythemia complicating twin-twin transfusion syndrome affect outcome after fetoscopic laser surgery?

    Donepudi, R; Papanna, R; Snowise, S; Johnson, A; Bebbington, M; Moise, K J

    2016-03-01

    Twin anemia-polycythemia sequence (TAPS) can occur as a unique disease or as a complication of twin-twin transfusion syndrome (TTTS). Middle cerebral artery (MCA) Doppler studies are not currently part of the routine evaluation of monochorionic twins since they are not used in the Quintero staging system. As such, the true incidence of TAPS is unknown. We aimed to compare the characteristics and outcomes of twin pregnancies with TTTS complicated by spontaneous anemia-polycythemia vs those with TTTS alone. This was a secondary analysis of data collected prospectively from a cohort of 156 consecutive patients undergoing fetoscopic laser surgery for TTTS, between October 2011 and August 2014. TAPS was defined as discordance in the preoperative MCA peak systolic velocity (PSV), with one twin fetus having MCA-PSV ≤ 1.0 multiples of the median (MoM) and the other having MCA-PSV ≥ 1.5 MoM. Maternal demographics as well as preoperative, operative and postoperative variables were analyzed. Included in the final analysis were 133 patients with complete records: 11 cases with TTTS with anemia-polycythemia and 122 cases with TTTS alone. There was no difference in maternal body mass index, gestational age (GA) at procedure, rate of preterm prelabor rupture of membranes or GA at delivery between the two groups. Patients with TTTS and anemia-polycythemia were more likely to be older (P = 0.03) and parous (P = 0.04) and had a significantly lower number of placental anastomoses (P = 0.01). The dual live-birth rate was similar for both groups (P = 0.76). Cases of TTTS with anemia-polycythemia were more likely to be found in parous and older women and were characterized by fewer vascular anastomoses. TTTS with anemia-polycythemia was not associated with worse perinatal outcome after laser therapy. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

  1. Clinical therapeutic effects of intravitreal Ranibizumab injection combined laser photocoagulation for macular edema in BRVO

    Bin Liu

    2014-11-01

    Full Text Available AIM: To evaluate the clinical therapeutic efficacy of intravitreal ranibizumab injection combined grid laser photocoagulation for macular edema secondary to branch retinal vein occlusion(BRVO. METHODS: Forty-two confirmed cases(42 eyeswith macular edema secondary to BRVO were randomized into 3 groups, each group contained 14 eyes. The ranibizumab group was received intravitreal injection of ranibizumab(0.05mL, the laser group was received grid laser photocoagulation, and the combined group was received a second therapy of grid laser photocoagulation after 1wk of the intravitreal injection of ranibizumab. Recorded the best-corrected visual acuity(BCVAand the central macular thickness(CMTpreoperative and at 1, 3, 6mo after therapy. RESULTS: The BCVA and the CMT had no differences among three groups pretherapy(P>0.05. While BCVA was much better and CMT was reduced significantly posttherapy than pretherapy in all three groups(PPP>0.05. While the BCVA was better and the CMT was thinner in the combined group than ranibizumab group and laser group at every time point(PPCONCLUSION: The intravitreal ranibizumab injection combined grid laser photocoagulation is an effective treatment method for the macular edema secondary to BRVO, it is more effective in improving BCVA than intravitreal ranibizumab or grid laser photocoagulation alone.

  2. Photocoagulation of microvascular and hemorrhagic lesions of the vocal fold with the KTP laser.

    Hirano, Shigeru; Yamashita, Masaru; Kitamura, Morimasa; Takagita, Shin-ichi

    2006-04-01

    Ectasias and varices of the vocal fold are microvascular lesions that are often due to chronic abuse of the voice, and are occasionally encountered in association with other disorders such as polyps, Reinke's edema, and hematoma. The KTP laser can be used for photocoagulation of small vascular lesions, because the laser beam is well absorbed by hemoglobin, and damage to the epithelium is minimal. The present pilot study examined how the KTP laser could be used for microvascular lesions and their associated lesions. Twelve patients who had undergone phonomicrosurgery were enrolled in the present study. The microvascular lesions were treated by photocoagulation with the laser set at a low power of 1.5 W in the continuous mode, while preserving the epithelium, and associated lesions were then treated by microdissection with cold instruments. The postoperative phonatory function was assessed by maximum phonation time, a perceptual test rating (GRBAS scale), and stroboscopy. The procedures were completed successfully in all cases. An exceptional case of a small hemorrhagic polyp allowed treatment with the laser only. The postoperative stroboscopic findings, maximum phonation time, and perceptual test rating all showed significant improvement compared with the preoperative state. No adverse effects, such as scarring or reduction of the mucosal wave, were observed in the current series. KTP laser photocoagulation is a relatively simple and safe procedure for treating microvascular lesions of the vocal fold. It is not recommended for photocoagulation of hemorrhagic polyps or hematomas, because such lesions have little blood flow inside and thus photocoagulation is usually impossible or requires too much laser energy. However, photocoagulation of perimeter or feeding vessels of such disorders may facilitate the following procedure by avoiding unnecessary bleeding, as well as preventing recurrence of hemorrhagic lesions.

  3. Retinal hemodynamic influence of compound xueshuantong capsule on nonproliferative diabetic retinopathy after laser photocoagulation

    Yu-Yan Wang

    2014-07-01

    Full Text Available AIM: To observe retinal hemodynamic influence of compound xueshuantong capsule on nonproliferative diabetic retinopathy(NPDRafter laser photocoagulation. METHODS: A total of 41 patients(72 eyeswith NPDR after laser photocoagulation were enrolled in this study. They were all given compound xueshuantong capsule, and used color Doppler flow imaging for detection of retinal hemodynamics. RESULTS: After treatment, patients with retinal blood perfusion significantly improved; central retinal arterial peak systolic velocity(PSV, end-diastolic velocity(EDVand medial velocity(Vmwere increased, while the resistance index(RIdecreased. The difference have statistical significance(PCONCLUSION: Compound xueshuantong capsule can improve retinal blood perfusion for nonproliferative diabetic retinopathy after laser photocoagulation, which is related to improvement of visual prognosis.

  4. Clinical research of retinal laser photocoagulation and Ranibizumab on the treatment of neovascular glaucoma

    Wei-Peng Jiang

    2015-10-01

    Full Text Available AIM: To explore the improvement of visual function and the adverse reactions of retinal laser photocoagulation combined with ranibizumab for the treatment of neovascular glaucoma(NVG, to provide the basis for clinical treatment.METHODS: One hundred patients with 129 eyes in our hospital from January 2012 to June 2014 were selected. They were randomly divided into the observation group and the control group, 50 cases in each one. Patients in the control group(67 eyeswere treated with retinal laser photocoagulation, and those in the observation group(62 eyeswere given retinal laser photocoagulation combined with ranibizumab treatment. After the treatment, the degeneration of iris neovascularization, visual acuity, intraocular pressure, ocular fundus and the adverse reactions were evaluated. Optical coherence tomography(OCTwas used to detect retinal nerve fiber layer(RNFLthickness and visual field defect. RESULTS: The degeneration rate of the iris neovascularization in the observation group was 95.2%(59/62, higher than that of the control group 83.6%(56/67(PPPPPP>0.05.CONCLUSION: The treatment of NVG with laser photocoagulation combined with ranibizumab has good clinical efficacy, and can significantly improve the vision and retinal structure and function of the patients, and is safer.

  5. Recurrent central serous chorioretinopathy after peripheral retinal laser photocoagulation: a case report.

    Semeraro, Francesco; Russo, Andrea; Delcassi, Luisa; Costagliola, Ciro

    2013-01-01

    To report a case of recurrent central serous chorioretinopathy (CSC) after performing peripheral laser photocoagulation for retinal degenerations. A 44-year-old woman with ocular history of CSC presented to the emergency room of our department complaining of heavy photopsia due to retinal tuft and lattice degenerations, and underwent laser photocoagulation to prevent retinal detachment. Two days after laser treatment, the visual acuity dropped, and optical coherence tomography scan showed the onset of CSC. The serous detachment completely resolved in 20 days with no therapy. A new CSC episode occurred in the same eye after another analogous laser treatment and, similarly, quickly resolved spontaneously. We reviewed the literature and discuss the possibility that laser-induced inflammation could rouse an inflammatory cascade mediated by proinflammatory cytokines and PAI-1, leading to the exacerbation of retinal serous detachment in susceptible patients.

  6. Demarcation laser photocoagulation of selected macula-sparing rhegmatogenous retinal detachments.

    Vrabec, T R; Baumal, C R

    2000-06-01

    To report a series of macula-sparing rhegmatogenous retinal detachments (MSRRDs) treated with demarcation laser photocoagulation (DLP). Retrospective, noncomparative case series. Thirty-one patients (34 eyes) with primary or recurrent MSRRDs without associated visual field loss, necrotizing retinitis, or proliferative vitreoretinopathy (PVR), managed with DLP from November 1992 through May 1999. Demarcation laser photocoagulation consisting of a triple row of confluent laser burns. Best corrected postoperative visual acuity and MSRRD progression or recurrence. Thirty-four primary and recurrent MSRRDs were treated by DLP, which consisted of a triple row of confluent laser burns. Macula-sparing rhegmatogenous retinal detachments were located in all quadrants and affected 10% to 45% of the retina. Findings associated with MSRRDs included lattice degeneration (12 eyes), vitreous hemorrhage (4 eyes), and demarcation line (9 eyes). Symptoms (photopsias or floaters) were associated with 14 MSRRDs. Eight eyes were myopic and 11 were pseudophakic. Thirty-two MSRRDs were shallow, two were dome shaped, and all were smooth without corrugations. Follow-up ranged from 1.5 to 80 months (mean, 15.8 months; median, 17 months). Thirty-three of 34 detachments remained stable after DLP. Three flattened spontaneously. One eye was managed with scleral buckle 6 weeks after DLP. Progression was attributed to incomplete laser treatment. Best corrected postoperative visual acuity was the same or improved in all but one eye, in which a cataract developed. Demarcation laser photocoagulation is an effective method to manage acute or chronic, primary or recurrent MSRRDs without associated PVR that are shallow and smooth without corrugations. Demarcation laser photocoagulation is an alternative to both observation and surgical repair for these select MSRRDs.

  7. Combination of Anti-VEGF and Laser Photocoagulation for Diabetic Macular Edema: A Review

    Laura N. Distefano

    2017-01-01

    Full Text Available Diabetic macular edema (DME is the most common cause of vision loss in diabetic patients. Thirty years ago, the Early Treatment Diabetic Retinopathy Study (ETDRS demonstrated that focal/grid laser photocoagulation reduces moderate vision loss from DME by 50% or more; thus, macular photocoagulation became the gold standard treatment for DME. However, with the development of anti-VEGF drugs (bevacizumab, ranibizumab, and aflibercept, better outcomes were obtained in terms of visual acuity gain and decrease in macular thickness in some studies when antiangiogenic drugs were administered in monotherapy. Macular laser therapy may still play an important role as an adjuvant treatment because it is able to improve macular thickness outcomes and reduce the number of injections needed. Here, we review some of the clinical trials that have assessed the efficacy of macular laser treatment, either as part of the treatment protocol or as rescue therapy.

  8. Krypton laser photocoagulation induces retinal vascular remodeling rather than choroidal neovascularization.

    Behar-Cohen, F; Benezra, D; Soubrane, G; Jonet, L; Jeanny, J C

    2006-08-01

    The purpose of this study is to analyze the retina and choroid response following krypton laser photocoagulation. Ninety-two C57BL6/Sev129 and 32 C57BL/6J, 5-6-week-old mice received one single krypton (630 nm) laser lesion: 50 microm, 0.05 s, 400 mW. On the following day, every day thereafter for 1 week and every 2-3 days for the following 3 weeks, serial sections throughout the lesion were systematically collected and studied. Immunohistology using specific markers or antibodies for glial fibrillary acidic protein (GFAP) (astrocytes, glia and Muller's cells), von Willebrand (vW) (vascular endothelial cells), TUNEL (cells undergoing caspase dependent apoptosis), PCNA (proliferating cell nuclear antigen) p36, CD4 and F4/80 (infiltrating inflammatory and T cells), DAPI (cell nuclei) and routine histology were carried out. Laser confocal microscopy was also performed on flat mounts. Temporal and spatial observations of the created photocoagulation lesions demonstrate that, after a few hours, activated glial cells within the retinal path of the laser beam express GFAP. After 48 h, GFAP-positive staining was also detected within the choroid lesion center. "Movement" of this GFAP-positive expression towards the lasered choroid was preceded by a well-demarcated and localized apoptosis of the retina outer nuclear layer cells within the laser beam path. Later, death of retinal outer nuclear cells and layer thinning at this site was followed by evagination of the inner nuclear retinal layer. Funneling of the entire inner nuclear and the thinned outer nuclear layers into the choroid lesion center was accompanied by "dragging" of the retinal capillaries. Thus, from days 10 to 14 after krypton laser photocoagulation onward, well-formed blood capillaries (of retinal origin) were observed within the lesion. Only a few of the vW-positive capillary endothelial cells stained also for PCNA p36. In the choroid, dilatation of the vascular bed occurred at the vicinity of the

  9. Combination of Laser Photocoagulation and Intravitreal Bevacizumab in Aggressive Posterior Retinopathy of Prematurity.

    Altinsoy, Halil Ibrahim; Mutlu, Fatih Mehmet; Güngör, Riza; Sarici, S Ümit

    2010-03-09

    The response to combined laser photocoagulation and a single intravitreal injection of 0.75 mg bevacizumab to each eye on separate days in two patients with aggressive, posterior retinopathy of prematurity (ROP) is described. Combined treatment resulted in regression of zone-1 disease in Case 1, which had no retinal detachment. However, no significant regression or unfavorable anatomic response was observed in the second case with retinal detachment. Although the combination of laser photocoagulation and intravitreal bevacizumab injection seems to be well tolerated, inducing prompt regression of agressive zone-1 ROP without retinal detachment, further controlled studies with long-term follow-up are necessary for their use in the treatment of ROP with for potentially dangerous growth factor inhibitors in premature babies. Copyright 2010, SLACK Incorporated.

  10. LASER PHOTOCOAGULATION IN DIABETIC MACULAR EDEMA: EFFECTS ON VISUAL ACUITY AND MACULAR EDEMA

    M.H. Dehghan

    1999-06-01

    Full Text Available Due to the importance of clinically significant macular edema in diabetic patients, this study is aimed to determine if laser photocoagulation is effective in the treatment of clinically significant diabetic macular edema. In addition, the effects of risk factors arc surveyed* This is an existing data study considering patients with clinically significant diabetic macular edema, treated with argon-green laser photocoagulation in Labbafinejad hospital, department of lasertherapy, from 1995 to 1997. in 60 (42.6% eyes the treatment method was focal, in 22 (15.6% eyes grid, and in 59 (41.84 modified grid laser photocoagulation was performed. The results are based upon deterioration of visual acuity, occurance of moderate visual loss and improvement or persistence of CSME. We studied 114 eyes from 87 patients. Two years after initial treatment, visual acuity improved in 19.1% of eyes, unchanged in 9.5% and worsened in 71.4% of eyes. After this period the rate of moderate visual loss was 28.6% and CSME was improved in 23.8% of eyes. According to our study, baseline visual acuity and retinopathy severity were two important intervening factors in response to lasertherapy. Comparing our results with natural course of diabetic macular edema, indicates that in assessing visual outcome laser photocoagulation is an effective modality in treatment of CSME, but it is not effective in maintaining or improving visual acuity, which is due to patients delay in visiting ophthalmologists and paying not enough attention to follow-up visits.

  11. Active iris vascular tufts bleeding successfully treated with argon laser photocoagulation.

    Sarmad, Ambreen; Alfaqawi, Fadi; Chakrabarti, Monali; Mitra, Arijit; Mushtaq, Bushra

    2018-03-01

    Iris vascular tufts (IVT) are rare biomicroscopic capillary outgrowths from the pupillary margins. Patients are usually asymptomatic until presenting with blurred vision due to spontaneous hyphema or with raised intraocular pressure. A 61-year-old woman presented to eye casualty with left eye (LE) blurred vision and discomfort for 1 day. Her external ocular examination was unremarkable and visual acuity was 6/6 in the right eye (RE) and 6/9 in the LE. Biomicroscopic examination revealed a 2-mm hyphema in her LE and bilateral multiple small IVT and active bleeding from IVT at the pupillary margin of the LE at the 5 o'clock position. Diagnosis of LE active bleeding from IVT was made and she underwent argon laser photocoagulation directed at the source of bleeding. The bleeding stopped immediately after the second burn. She was followed up for 3 months; her visual acuity was 6/5 and 6/6 in the RE and LE, respectively, with no further problems. Iris vascular tufts are benign and recurrent hemorrhages are unlikely. Therefore, definitive argon laser photocoagulation or surgical treatment are reserved to arrest further episodes of hyphema. Our case demonstrates the effective use of argon laser photocoagulation to completely arrest active bleeding from IVT and excellent recovery of hyphema with no further problems for 5 years.

  12. Posterior Pole Sparing Laser Photocoagulation Combined with Intravitreal Bevacizumab Injection in Posterior Retinopathy of Prematurity

    Rebecca Kim

    2014-01-01

    Full Text Available Purpose. To report the results of the posterior pole sparing laser photocoagulation combined with intravitreal bevacizumab injection (IVB in retinopathy of prematurity (ROP. Methods. A retrospective chart review of premature babies with ROP, all of whom received laser photocoagulation with IVB. Eleven eyes of 6 infants with advanced zone I ROP underwent laser ablation sparing posterior pole with concurrent IVB. The results were compared with those of full-laser treatment combined with IVB to 8 eyes of 5 infants with advanced ROP without involvement of the posterior pole. Results. The posterior pole sparing laser with IVB was performed with zone I, stage 3+ ROP at the mean postmenstrual age of 36 weeks and 5 days. The plus sign decreased significantly at postoperative day 1, the neovascular proliferation regressed by postoperative week 1, and the normal vascularization started at postoperative day 32 on the average. Two months after treatment, vascularization of the spared avascular area was completed. There was no macular dragging, tractional retinal detachment, foveal destruction by laser scars, or any other adverse event. No significant anatomical differences were identified from those of full-laser ablation combined with IVB. Conclusions. Posterior pole sparing laser with IVB can give favorable results without destruction of posterior pole retina.

  13. Protective effect of basic fibroblast growth factor on retinal injury induced by argon laser photocoagulation

    Chen, P; San, Q; Wang, C Z; Yang, Z F; Kang, H X; Qian, H W; Zhang, C P

    2010-01-01

    Laser photocoagulation treatment is often complicated by a side effect of visual impairment, which is caused by the unavoidable laser-induced retinal destruction. At present no specific is found to cure this retinopathy. The aim of this study was to observe the neuroprotective effect of bFGF on laser-induced retinal injury. Chinchilla rabbits were divided into three groups and argon laser lesions were created in the retinas. Then bFGF or dexamethasone, a widely used ophthalmic preparation, or saline was given severally by retrobulbar injection. The retinal lesions were evaluated histologically and morphometrically, and visual function was examined by ERG. The results showed that bFGF administration better preserved morphology of retinal photoreceptors and significantly diminished the area of the lesions. Furthermore, bFGF promoted the restoration of the ERG b-wave amplitude. In rabbits treated with dexamethasone, however, the lesions showed almost no ameliorative changes. This is the first study to investigate the potential role of bFGF as a remedial agent in laser photocoagulation treatment. These findings suggest that bFGF has significant neuroprotective properties in the retina and this type of neuroprotection may be of clinical significance in reducing iatrogenic laser-induced retinal injuries in humans

  14. Pattern scan laser versus single spot laser in panretinal photocoagulation treatment for proliferative diabetic retinopathy

    Shu Zhang

    2017-02-01

    Full Text Available AIM: To investigate the efficacy of 577-nm pattern scan laser in panretinal photocoagulation(PRPtreatment in newly diagnosed proliferative diabetic retinopathy(PDR.METHODS:Prospective and comparative observation was performed in totally 32 patients with high-risk PDR. They were randomly divided into group 1(using pattern scan laser, PSLand 2(using single spot laser, SSL, each containing 16 subjects to which totally 20 eyes received PRP. Non-perfusion region was identified with fundus fluorescein angiography(FFAbefore and 3mo after final PRP. The advantage of PSL was verified in terms of the number and the duration of PRP sessions needed for satisfactory outcomes, and the pain score.RESULTS: Three PRP sessions were needed for each eye to complete the treatment using PSL, while 4 sessions were needed using SSL. The duration of each session with PSL in group 1 was 7.3±2.3min, which was significantly shorter than that with SSL in group 2(13.2±4.1, t38=5.596, PPCONCLUSION: PSL showed clear advantages over SSL in the PRP treatment of PDR, not only in the improved efficacy, but also in the reduction of pain and the improvement of effectiveness.

  15. Curative effect of Ranibizumab combined with laser photocoagulation for proliferative diabetic retinopathy

    Fan-Yi Meng

    2018-04-01

    Full Text Available AIM:To investigate the clinical efficacy of Ranibizumab combined with laser photocoagulation in the treatment of proliferative diabetic retinopathy(PDR. METHODS: Totally 80 patients(101 eyeswith PDR admitted to our hospital from October 2014 and October 2016 were selected and divided into the observation group and the control group, with 50 eyes and 51 eyes respectively. The patients in the control group(50 eyeswere treated with panretinal photocoagulation(PRP, and the patients in observation group(51 eyeswere treated with ranibizumab on the basis of PRP treatment. Best corrected visual acuity(BCVAwas compared before and after surgery 1, 3, and 6mo. Optical coherence tomography(OCTwas used to examine the central macular thickness(CMTand the area of neovascularization at each timepoints. Then the laser spot number, laser energy and energy density were compared between the two groups and the adverse reactions were recorded. RESULTS: Postoperative BCVA of the two groups significantly increased, and the BCVA of observation group were significantly higher than that of the control group after surgery 1, 3, 6mo, the difference was statistically significant(PPPCONCLUSION: Ranibizumab combined with laser in the treatment of PDR is an effective and safe way to improve BCVA, reduce CMT, and eliminate new blood vessels with less required laser energy.

  16. Fetoscopic laser coagulation of intertwin anastomoses reduces discordant placental autophagic activities in discordant twin growth

    Yao-Lung Chang

    2015-10-01

    Conclusion: The discordance of placenta autophagic activity in the monochorionic twin with sIUGR was reduced after laser coagulation of the intertwin anastomoses, which may result from the effect of correction of the discordant intertwin placenta perfusion.

  17. [Nd-YAG laser photocoagulation of scrotal sebaceous cysts].

    Franco de Castro, A; Truhán, D; Carretero González, P; Alcover García, J

    2002-02-01

    Scrotum's sebaceous cyst is an usual pathology, not life threatening, but susceptible of infection, producing abscess with their associated cosmetic and psychological disturbance. The classical management is the complete excision, under local anaesthesia, to prevent its recidive. Until today, the use of de Nd-YAG laser for the management of the scrotum's sebaceous cysts as not been reported. We report a case of a young man with several scrotum's sebaceous cysts, treated successfully with the use of a Nd-YAG laser.

  18. Determination of pulse profile characteristics of multi spot retinal photocoagulation lasers.

    Clarkson, Douglas McG; Makhzoum, Osama; Blackburn, John

    2015-10-01

    A system is described for determination of discrete pulse train characteristics of multi spot laser delivery systems for retinal photocoagulation. While photodiodes provide an ideal detection mechanism, measurement artifacts can potentially be introduced by the spatial pattern of the delivered beam relative to a discrete photodiode element. This problem was overcome by use of an integrating sphere to produce a uniform light field at the site of the photodiode detector. A basic current driven photodiode detection circuit incorporating an operational amplifier was used to generate a signal captured by a commercially available USB interface device at a rate of 10 kHz. Studies were undertaken of a Topcon Pascal Streamline laser system with output at a wavelength of 577 nm (yellow). This laser features the proprietary feature of 'Endpoint Management' ™ where pulses can be delivered as 100% of set energy levels with visible reaction on the retina and also at a reduced energy level to create potentially non visible but clinically effective lesions. Using the pulse train measurement device it was identified that the 'Endpoint Management' ™ delivery mode of pulses of lower energy was achieved by reducing the pulse duration of pulses for non-visible effect pulses while maintaining consistent beam power levels within the delivered pulse profile. The effect of eye geometry in determining safety and effectiveness of multi spot laser delivery for retinal photocoagulation is discussed. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  19. Comparison of pain scores between patients undergoing panretinal photocoagulation using navigated or pattern scan laser systems

    Umit Ubeyt Inan

    2016-02-01

    Full Text Available ABSTRACT Purpose: To compare the pain responses of patients with proliferative diabetic retinopathy (PDR undergoing panretinal photocoagulation (PRP using either pattern scan laser (PASCAL or navigated laser photocoagulation (NAVILAS. Methods: Patients diagnosed with PDR were randomly assigned to undergo either PASCAL or NAVILAS photocoagulation treatment. PRP was performed using the multi-shot mode with a spot size of 200-400 µm and a pulse duration of 30 ms to obtain a white-grayish spot on the retina. Parameters were identical in both procedures. After 30 min of PRP application, patients were asked to verbally describe their pain perception as either "none," "mild," "moderate," "severe," or "very severe" using a verbal rating scale (VRS and visual analog scale (VAS by indicating a score from "0" to "10," representing the severity of pain from "no pain" to "severe pain." Results: A total of 60 eyes of 60 patients (20 females and 40 males diagnosed with PDR were treated. The mean age of patients was 62.22 ± 9.19 years, and the mean diabetes duration was 195.47 ± 94.54 months. The mean number of laser spots delivered during PRP was 389.47 ± 71.52 in the NAVILAS group and 392.70 ± 54.33 in the PASCAL group (p=0.57. The difference in pain responses between patients in the NAVILAS and PASCAL groups was significant with regard to the mean VRS (1.10 ± 0.67 and 1.47 ± 0.69, respectively; p=0.042 and mean VAS (2.13 ± 1.17 and 2.97 ± 1.35, respectively; p=0.034 scores. Conclusions: Pain responses in patients undergoing PRP with a 30-ms pulse duration were significantly milder in the NAVILAS group than in the PASCAL group.

  20. Factors affecting reading speed in patients with diabetic macular edema treated with laser photocoagulation.

    Elizabeth Pearce

    Full Text Available PURPOSE: To study the factors that may affect reading speed in patients with diabetic macular edema previously treated with laser photocoagulation. METHODS: Consecutive patients with type II diabetes treated with laser photocoagulation for diabetic macular edema (DME at least twelve months previously, with best corrected visual acuity of better than 65 letters (approximately 20/40 measured with Early Treatment Diabetic Retinopathy Study (ETDRS charts were included in this study. Patients previously treated with pan-retinal photocoagulation, vitrectomy, intravitreal steroid or anti-VEGF therapy were excluded. Any other ocular co-morbidities that may influence reading ability such as cataract, glaucoma or macular degeneration were also excluded. All patients were refracted by a certified examiner, the following measurements were collected: best corrected visual acuity (BCVA, contrast sensitivity with Pelli-Robson chart, reading speed with MNREAD chart, microperimetry with Nidek MP1, and central subfield thickness with Zeiss spectral domain optical coherent topography. RESULTS: The slow reading group had poorer contrast sensitivity (p = 0.001, reduced retinal sensitivity (p = 0.027 and less stable fixation (p = 0.013. Most interestingly the reduced retinal sensitivity findings were driven by the microperimetry value on the right subfield (p = 0.033, (nasal to the fovea in the right eye and temporal to the fovea in the left eye. Multiple linear regression analysis showed that contrast sensitivity is probably the most important factor that affects reading speed (p = 0.001. CONCLUSION: Reduced retinal sensitivity after laser treatment is associated with reduced reading speed in patients with diabetic macular edema.

  1. Ultrasound-guided interstitial laser photocoagulation of an autonomous thyroid nodule

    Døssing, Helle; Bennedbaek, Finn Noe; Hegedüs, Laszlo

    2003-01-01

    effects and often necessitates multiple treatment sessions. We present a case of a 17-year-old female successfully treated with ultrasound (US)-guided percutaneous interstitial laser photocoagulation (ILP) for an AFTN. Initially, she had a serum thyrotropin (TSH) of 0.01 mU/L and normal peripheral thyroid.......9 mL (40% reduction) without further alterations during an additional 9 months of follow-up. Side effects were transient thyrotoxicosis and local pain as seen with PEI. To our knowledge, this is the first reported case of ILP used in a patient with a pretoxic thyroid nodule. US-guided thermic tissue...

  2. Failure of pan-retinal laser photocoagulation to regress ...

    Objectives: (i) To illustrate the occurrence of failure of regression of neovascularization (NV) following adequate initial and supplemental pan-retinal laser photo- coagulation (PRP) using 3 case histories (ii) To review the literature on possible aetiogenesis and further management options. Methods: The hospital records of 3 ...

  3. Observation of clinical efficacy of pattern scan laser photocoagulation on diabetic retinopathy

    Zhi-Hua Peng

    2013-08-01

    Full Text Available AIM: To evaluate the clinical efficacy of pattern scan laser photocoagulation(Pascalon proliferative diabetic retinopathy(PDR.METHODS: A total of 93 patients with retinopathy(186 eyeswere randomly divided into treatment group(96 eyes of 48 patientswho treated with panretinal photocoagulation(PRPusing Pascal at one time and control group(90 eyes of 45 patientswho treated with PRP using multi-wavelength krypton laser in 4-5 times. The visual acuity, FFA, OCT, visual field will be evaluated of each patient before and after the treatment.RESULTS: The visual acuity findings were stated as below: the overall effective rate of visual acuity in treatment group is 85.4% while it is 82.2% in control group. The overall effective rate in two groups has no significant difference. The retinal sensitivity has no significant decrease in the treatment group while which decreased significantly in the control group.CONCLUSION: The clinical efficacy of Pascal on treating the PDR is better than which of the regular argon laser. The field of vision has no significant narrowed after the Pascal treatment which can efficiently shorten the length of treatment and reduce the pain sensation.

  4. Venous Lake of the Lips Treated Using Photocoagulation with High-Intensity Diode Laser

    Galletta, Vivian C.; de Paula Eduardo, Carlos; Migliari, Dante A.

    2010-01-01

    Abstract Objective: To evaluate the effectiveness of photocoagulation with high-intensity diode laser in the treatment of venous lake (VL) lesions. Background Data: VL is a common vascular lesion characterized by elevated, usually dome-shaped papules, ranging in color from dark blue to dark purple, seen more frequently in elderly patients. They often occur as single lesions on the ears, face, lips, or neck. Once formed, lesions persist throughout life. Although these lesions are usually asymptomatic, they can bleed if injured. Methods: Seventeen patients (7 men and 10 women) with VL on the lip were treated using a noncontact diode laser (wavelength 808 nm, power output 2–3 W in continuous wave). Results: After only one irradiation exposure, all lesions were successfully treated. Healing was completed in approximately 2 to 3 weeks, and none of the patients experienced complications. Postoperative discomfort and scarring were not present or were minimal. Conclusion: Photocoagulation with high-intensity diode laser is an effective, bloodless procedure for the treatment of VL. PMID:19811083

  5. Utility of large spot binocular indirect laser delivery for peripheral photocoagulation therapy in children.

    Balasubramaniam, Saranya C; Mohney, Brian G; Bang, Genie M; Link, Thomas P; Pulido, Jose S

    2012-09-01

    The purpose of this article is to demonstrate the utility of the large spot size (LSS) setting using a binocular laser indirect delivery system for peripheral ablation in children. One patient with bilateral retinopathy of prematurity received photocoagulation with standard spot size burns placed adjacently to LSS burns. Using a pixel analysis program called Image J on the Retcam picture, the areas of each retinal spot size were determined in units of pixels, giving a standard spot range of 805 to 1294 pixels and LSS range of 1699 to 2311 pixels. Additionally, fluence was calculated using theoretical retinal areas produced by each spot size: the standard spot setting was 462 mJ/mm2 and the LSS setting was 104 mJ/mm2. For eyes with retinopathy of prematurity, our study shows that LSS laser indirect delivery halves the number of spots required for treatment and reduces fluence by almost one-quarter, producing more uniform spots.

  6. Cutaneous progressive angiomatosis on the muzzle of a dog, treated by laser photocoagulation therapy.

    Olivieri, Lara; Nardini, Giordano; Pengo, Graziano; Abramo, Francesca

    2010-10-01

    A 10-year old, female, cocker spaniel was presented with a bleeding lesion on the muzzle and nasal planum observed initially as a small raised nodule at 1 year of age. This became clinically more pronounced at 5 years of age, progressively enlarged thereafter and was diagnosed initially as a vascular tumour. On clinical examination, multiple confluent nodules of variable diameter (0.5-1.5 cm) deformed the outline of the nose. Histological examination revealed a progressive angiomatosis with multifocal infiltrative growth of increased dermal vascularization with different sized and type of anastomosing vessels lined by a monolayer of reactive endothelium, often arranged as papillary projections into the lumina. Partial nosectomy, the first therapeutic approach, was unsuccessful and the lesion relapsed within 6 months. However, subsequent laser photocoagulation therapy provided a good cosmetic outcome, no relapse 1 year later, and appeared to provide an effective alternative to ablation surgery. © 2010 The Authors. Journal compilation © 2010 ESVD and ACVD.

  7. Experience with the Pascal® photocoagulator: An analysis of over 1200 laser procedures with regard to parameter refinement

    Sheth Saumil

    2011-01-01

    Full Text Available Aim: To systematically refine and recommend parameter settings of spot size, power, and treatment duration using the Pascal® photocoagulator, a multi-spot, semi-automated, short-duration laser system. Materials and Methods: A retrospective consecutive series with 752 Caucasian eyes and 1242 laser procedures over two years were grouped into, (1 374 macular focal / grid photocoagulation (FP, (2, 666 panretinal photocoagulation (PRP, and (3 202 barrage photocoagulation (BP. Parameters for power, duration, spot number, and spot size were recorded for every group. Results: Power parameters for all groups showed a non-gaussian distribution; FP group, median 190 mW, range 100 - 950 mW, and PRP group, median 800 mW, range 100 - 2000 mW. On subgroup comparison, for similar spot size, as treatment duration decreased, the power required increased, albeit in a much lesser proportion than that given by energy = power x time. Most frequently used patterns were single spot (89% of cases in FP, 5 Χ 5 box (72% in PRP, and 2 Χ 2 box (78% in BP. Spot diameters as high as ≈ 700 μm on retina were given in the PRP group. Single session PRP was attempted in six eyes with a median spot count of 3500. Conclusion: Overall, due to the small duration of its pulse, the Pascal® photocoagulator tends to use higher powers, although much lower cumulative energies, than those used in a conventional laser. The consequent lesser heat dissipation, especially lateral, can allow one to use relatively larger spot sizes and give more closely spaced burns, without incurring significant side effects.

  8. Laser photocoagulation at birth prevents blindness in Norrie's disease diagnosed using amniocentesis.

    Chow, Clement C; Kiernan, Daniel F; Chau, Felix Y; Blair, Michael P; Ticho, Benjamin H; Galasso, John M; Shapiro, Michael J

    2010-12-01

    To report the first case of prophylactic laser treatment to prevent blindness in a patient who was diagnosed with Norrie's disease by genetic testing with amniocentesis. Case report. A 2-year-old white boy with Norrie's disease. A 37-week gestational age male with a family history of Norrie's disease was born via Cesarean section after the mother had undergone prenatal amniocentesis fetal-genetic testing at 23 weeks of gestation. A C520T (nonsense) mutation was found in the Norrie's disease gene. After examination under anesthesia confirmed the diagnosis on the first day of life, laser photocoagulation was applied to the avascular retina bilaterally. The patient was followed closely by ophthalmology, pediatrics, and occupational therapy departments. Functional outcome, as documented by Teller visual acuity and formal occupational therapy testing, and anatomic outcome, as documented by Retcam photography and fluorescein angiography. Complete regression of extraretinal fibrovascular proliferation was observed 1 month after laser treatment. No retinal detachment had occurred to date at 24 months. Teller visual acuity at 23 months of life was 20/100 in both eyes. The patient's vision and developmental milestones were age appropriate. Pre-term genetic diagnosis with immediate laser treatment after birth may preserve vision in individuals affected with Norrie's disease. Copyright © 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  9. Management of peripheral polypoidal choroidal vasculopathy with intravitreal bevacizumab and indocyanine green angiography-guided laser photocoagulation

    Pukhraj Rishi

    2012-01-01

    Full Text Available A 69-year-old lady presented with complaints of decreased vision in left eye since one month. Best Corrected Visual Acuity (BCVA was 6/18 in that eye. Fundus examination revealed non-central geographic atrophy and soft drusens at macula in both eyes. Temporal periphery of left eye revealed subretinal exudates with altered sub-RPE hemorrhage mimicking peripheral exudative hemorrhagic chorioretinopathy (PEHCR. Fundus Fluorescein Angiogram showed window defects at macula and blocked fluorescence at temporal periphery in left eye. However, Indocyanine green angiography (ICGA revealed active peripheral choroidal polyps. The patient was successfully treated with intravitreal bevacizumab and ICGA-guided laser photocoagulation. 27 months after laser treatment, BCVA improved to 6/9. Rationale of consecutive anti-vascular endothelial growth factor (VEGF treatment followed by more definitive laser photocoagulation is that anti-VEGF aids in resolution of subretinal fluid, thus making the polyp more amenable to focal laser photocoagulation which stabilizes the choroidal vasculature and prevents further leakage.

  10. The evaluation of efficacy of subtenon triamcinolone injection combined with focal laser photocoagulation in diabetic macular edema

    Hüseyin Öksüz

    2012-06-01

    Full Text Available Objectives: The aim of this study was to investigate efficacyand safety of subtenon triamcinolone (ST in combinationwith focal laser photocoagulation in diabetic macularedema (DME.Materials and methods: Medical records of patients withDME, treated with 40 mg subtenon injection of triamcinoloneacetonid prior to focal laser photocoagulation wereretrospectively analyzed. Seventeen eyes of 17 patientswith DME were enrolled in the study. All patients underwenta comprehensive ophthalmological examinationbefore the treatment. Efficacy of the treatment after STinjection was evaluated by visual acuity and flouresceinangiography (FA. Follow-up visits were performed at 1st,3rd, 6th and 12th months. Repeated measures ANOVA wasused for statistical analysis.Results: The mean age was 61.5 ± 8.7 years and themean visual acuity in the study eyes was 0.22 ± 0.13 beforethe treatment, 0.39 ± 0.15 at 1st month, 0.36 ± 0.18at 3rd month, 0.33 ± 0.15 at 6th month and 0.34 ± 0.16 at12th month. The differences in the visual acuity before thetreatment and follow-up visits were significant (p ˂0.05.Visual acuity was increased in 13 (%76,4 patients, decreasedin 1 (%5,8 and unchanged in 3 (%17,6.Conclusion: Injection of 40 mg of triamsinolon via subtenonroute combined with focal laser photocoagulation isa safe and beneficial treatment in cases of DME

  11. Endoscopic treatment by snare electrocoagulation prior to Nd:YAG laser photocoagulation in 85 voluminous colorectal villous adenomas.

    Aubert, A; Meduri, B; Fritsch, J; Aime, F; Baglin, A; Barbagelata, M

    1991-05-01

    The association of endoscopic resection with Nd:YAG laser photocoagulation was used to treat benign colorectal villous adenomas. Eight-five patients were included: 49 with surgical contraindications, 35 for whom surgical resection appeared to be too hazardous, and 1 who refused surgery. Forty-five tumors had an axial extension between 1 and 3 cm, and 40 tumors had an axial extension of at least 4 cm. Diathermic snare resection was performed to remove large tumoral fragments prior to laser photocoagulation of the residual flat lesions. Treatments were repeated every 15 days until total tumor destruction was achieved. A carcinoma was detected in biopsy specimens obtained during endoscopic treatment of five patients. Two patients were lost to follow-up. Treatment results could be analyzed in 78 patients. Successful treatment was achieved in 67 patients. Tumor destruction was complete in 77 percent of patients who had lesions of at least 4 cm diameter and in 93 percent of patients with smaller lesions. The axial extension of the tumor was the main factor affecting the results of treatment. No major complications occurred. During the average 103-week follow-up period, 21 percent of the patients with total tumor destruction had a recurrence. The risk of recurrence was correlated with the number of initial treatment sessions and previous surgery treatment. It would appear that the treatment with endoscopic resection prior to Nd:YAG laser photocoagulation is a safe and effective method in the destruction of colorectal villous adenomas.

  12. Randomized controlled trial comparing Nd:YAG laser photocoagulation and bipolar electrocautery in the management of epistaxis.

    Zhang, Jing; Cao, Luhong; Wei, Chunsheng

    2017-09-01

    The objective of this study is to evaluate the efficacy and degree of comfort of Nd:YAG laser photocoagulation compared to bipolar electrocautery in the management of epistaxis. Seventy-two consecutive patients with a history of epistaxis were randomly assigned to receive treatment in an outpatient setting consisting of either bipolar electrocautery (group 1) or Nd:YAG laser photocoagulation (group 2). The study was conducted in university-affiliated teaching hospital. Seventy-two consecutive patients who suffered from anterior epistaxis and presented to the Otolaryngology Department at the Eye, Ear, Nose and Throat Hospital, Fudan University, between June 2015 and August 2015. The following outcome measures were assessed: bleeding intensity, bleeding frequency 4 and 16 weeks after treatment (0 = no bleeding, 1 = reduced bleeding, 2 = the same, and 3 = worse), participant perception of discomfort during treatment (grade 0-10, where 10 is the worst pain), and therapy duration and complications. At 16 weeks, 91% of the laser patients versus 91% of the bipolar electrocautery patients had no reported bleeding. The outcome scores at 4 and 16 weeks after treatment showed no significant difference between the two groups (P = 0.5 and P = 0.98, respectively; P > 0.05). The median pain levels experienced during the office laser and bipolar electrocautery procedures were 3.0 and 4.0, respectively, and the median durations of the laser and electrocautery therapies were 3.0 and 4.0, respectively. Neither groups had complications. It can be concluded that Nd:YAG laser photocoagulation and bipolar electrocautery are both effective in the treatment of epistaxis. These two therapies are recommended. As a whole, these two therapies, performed in an office setting, are timely, efficacious, and well tolerated in the treatment of epistaxis.

  13. Single-Spot Yellow Laser Versus Conventional Green Laser on Panretinal Photocoagulation: Patient Pain Scores and Preferences.

    González-Saldivar, Gerardo; Rojas-Juárez, Sergio; Espinosa-Soto, Itzel; Sánchez-Ramos, Jorge; Jaurieta-Hinojosa, Noel; Ramírez-Estudillo, Abel

    2017-11-01

    Panretinal photocoagulation (PRP) is the mainstay therapy for proliferative diabetic retinopathy. Pain during and after its application is a complication that affects patients' therapeutic adherence. This study aimed to compare pain perception and patient preference for the 577-nm yellow laser (YL-577) (LIGHTL as 577; LIGHTMED, San Clemente, CA) and the conventional 532-nm green laser (GL-532) (Purepoint Laser; Alcon, Fort Worth, TX) with PRP. A total of 92 patient eyes with proliferative diabetic retinopathy treated with PRP were randomly assigned to receive both GL-532 and YL-577 (184 eyes) - one on each eye, with the order of application randomized, as well. Afterward, verbal rapid answer and visual analogue scale (VAS) scores for pain perception and patient preference were evaluated. VAS score was 7 ± 2 for the GL-532 group compared to 5 ± 3 in the YL-577 group (P = .001). Overall, 75% of the patients preferred YL-577 therapy if they were to receive a second PRP session. The use of YL-577 as an alternative approach for PRP reduces pain perception and is preferred by patients. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:902-905.]. Copyright 2017, SLACK Incorporated.

  14. Subthreshold diode-laser micropulse photocoagulation as a primary and secondary line of treatment in management of diabetic macular edema

    Othman IS

    2014-03-01

    Full Text Available Ihab Saad Othman,1 Sherif Ahmed Eissa,1 Mohamed S Kotb,1 Sherin Hassan Sadek21Cairo University, Cairo, 2Fayoum University, Al Fayoum, EgyptBackground: The purpose of this study was to evaluate subthreshold diode-laser micropulse (SDM photocoagulation as a primary and secondary line of treatment for clinically significant diabetic macular edema (CSDME.Methods: In this prospective nonrandomized case series, 220 cases of nonischemic CSDME were managed primarily and secondarily by SDM photocoagulation on a 15% duty cycle with a mean power of 828 mW and a spot size of 75–125 µm. SDM treatment was repeated at 3–4-month intervals if residual leakage was observed. Additional intravitreal pharmacologic therapy was used according to the response. Follow-up varied from 12 to 19 (mean 14±2.8 months. Novel software designed by the authors was used to record the subvisible threshold laser applications and their parameters on the fundus image of the eye. Evaluation of the results of treatment was done using fluorescein angiography and optical coherence tomography (OCT. Primary outcome measures included changes in visual acuity and foveal thickness at OCT. Secondary outcome measures included visual loss of one or more Snellen lines and laser scars detectable on fundus biomicroscopy or fluorescein angiography.Results: In the primary treatment group, there was significant improvement or stabilization of visual acuity after the first 3–4 months, which was stable thereafter. Visual acuity was stable in the secondary treatment group. A corresponding reduction of macular thickness on OCT was noted during the follow-up period in both groups. Additional therapy included repeat SDM photocoagulation, intravitreal injection of triamcinolone, and pars plana vitrectomy. Laser marks seen as changes in retinal pigment epithelium on fundus biomicroscopy and fluorescein angiography were noted in 3.3% and 5.7% of cases. Our novel software could accurately record the

  15. Comparison of Bevacizumab, Ranibizumab, and Laser Photocoagulation in the Treatment of Retinopathy of Prematurity in Turkey.

    Gunay, Murat; Sukgen, Emine Alyamac; Celik, Gokhan; Kocluk, Yusuf

    2017-03-01

    To evaluate the efficacies and treatment outcomes following intravitreal bevacizumab (IVB), intravitreal ranibizumab (IVR), and laser photocoagulation (LPC) in retinopathy of prematurity (ROP). This was a retrospective interventional case series study including the data of 134 infants (264 eyes) who were treated with IVB, IVR, or LPC for ROP. The data were collected from two major ROP treatment centers in Turkey without any randomization or masking. Regression of ROP, recurrence profile, complications after each treatment modality, and indications for retreatment were evaluated. The main outcome measures included the total inactivation of ROP with anatomic and refractive outcomes at 1.5 years of adjusted age. There were 55 infants (41.1%) in the IVB group, 22 infants (16.4%) in the IVR group, and 57 infants (42.5%) in the LPC group. All but 3 infants (5.5%) in the IVB group and 11 infants (50%) in the IVR group showed recurrence to stage 1 and 2 ROP following IVB and IVR (p < 0.001). Retreatment was performed in three infants in both IVB and IVR groups (p = 0.098). At 1.5 years of adjusted age, all infants showed favorable anatomic outcome except one infant in the LPC group. No significant difference of the mean spherical equivalent (SE) was observed between the groups (p = 0.131). In Zone I ROP, laser treated infants had significantly higher rates of myopia and high myopia than IVB and IVR treated infants (p = 0.040 and p = 0.019, respectively). Both IVB and IVR treated infants had significantly better refractive outcomes in Zone I ROP as compared to LPC treated infants at 1.5 years of adjusted age. The higher rate of disease recurrence was associated with IVR. Gestational age (GA) and the zone of ROP were also predictive factors for recurrence of ROP in the study.

  16. Analysis of failures and complications of neodymium: YAG laser photocoagulation in gastrointestinal tract tumors. A retrospective survey of 18 years' experience

    Mathus-Vliegen, E. M.; Tytgat, G. N.

    1990-01-01

    Eight years of experience with endoscopic Nd:YAG laser photocoagulation were analyzed in retrospect in an attempt to identify factors relating to both failures and complications of laser therapy, and to delineate its limits and pitfalls in benign and malignant tumors. Three hundred and seventy-eight

  17. Interstitial laser photocoagulation for benign thyroid nodules: time to treat large nodules.

    Amabile, Gerardo; Rotondi, Mario; Pirali, Barbara; Dionisio, Rosa; Agozzino, Lucio; Lanza, Michele; Buonanno, Luciano; Di Filippo, Bruno; Fonte, Rodolfo; Chiovato, Luca

    2011-09-01

    Interstitial laser photocoagulation (ILP) is a new therapeutic option for the ablation of non-functioning and hyper-functioning benign thyroid nodules. Amelioration of the ablation procedure currently allows treating large nodules. Aim of this study was to evaluate the therapeutic efficacy of ILP, performed according to a modified protocol of ablation, in patients with large functioning and non-functioning thyroid nodules and to identify the best parameters for predicting successful outcome in hyperthyroid patients. Fifty-one patients with non-functioning thyroid nodules (group 1) and 26 patients with hyperfunctioning thyroid nodules (group 2) were enrolled. All patients had a nodular volume ≥40 ml. Patients were addressed to 1-3 cycles of ILP. A cycle consisted of three ILP sessions, each lasting 5-10 minutes repeated at an interval of 1 month. After each cycle of ILP patients underwent thyroid evaluation. A nodule volume reduction, expressed as percentage of the basal volume, significantly occurred in both groups (F = 190.4; P nodule volume; (iii) total amount of energy delivered expressed in Joule. ROC curves identified the percentage of volume reduction as the best parameter predicting a normalized serum TSH (area under the curve 0.962; P thyroid nodules, both in terms of nodule size reduction and cure of hyperthyroidism (87% of cured patients after the last ILP cycle). ILP should not be limited to patients refusing or being ineligible for surgery and/or radioiodine. Copyright © 2011 Wiley-Liss, Inc.

  18. Effect of ultrasound-guided interstitial laser photocoagulation on benign solitary solid cold thyroid nodules - a randomised study

    Døssing, Helle; Bennedbaek, Finn Noe; Hegedüs, Laszlo

    2005-01-01

    AIM: To evaluate the efficacy of ultrasound (US)-guided interstitial laser photocoagulation (ILP) on thyroid function, nodule size and patient satisfaction in benign solitary solid cold thyroid nodules by comparing one ILP session with no treatment in a prospective randomised study. MATERIALS...... and thyroid function was determined by routine assays before and during follow-up. Pressure and cosmetic complaints before and at 6 months were evaluated on a visual analogue scale. ILP was performed under US guidance and with an output power of 2.5-3.5 W. RESULTS: In the ILP group, the nodule volume...

  19. Changes of plasma IL-6 and TNF-α levels during peri-operative period in patients undergoing laser photo-coagulation of greater saphenous varicosities

    Wang Taihan; Wang Chunxi

    2005-01-01

    Objective: To investigate the plasma levels of IL-6 and TNF-α during peri-operative period in patients undergoing laser photocoagulation of greater saphenous varicosities. Methods: Plasma IL-6 and TNF-α levels were determined with RIA before operation and 1, 3, 7, 14 days post-operatively in 110 patients with greater saphenous vein varicosity undergoing different forms of treatment (intravascular laser photo-coagulation 43, photo-coagulation combined with venous valve repair 35, high ligation and segmental stripping 32). Skin trophic disturbances were present in 56 of the 110 patients. Plasma IL-6 and TNF-α levels were also measured in 33 controls. Results: The plasma IL-6 and TNF-α levels in patients with skin trophic disturbances were significantly higher than those in controls (P<0.01), while levels in patients without skin lesions were not much changed. The plasma IL-6 and TNF-α levels were increased at first and dropped later to approaching pre-operative value by d14 in all the 110 patients after operation, however, the amount of increase was least and the normalization was also soonest in the simple photo-coagulation group, the reverse was true for the conventional operation group. Conclusion: Laser photo-coagulation is least stressful among the three types of operation and magnitude of changes of plasma IL-6 and TNF-α levels correctly reflects the intensity of stress. (authors)

  20. Clinicopathologic correlation of argon laser photocoagulation of retinal angiomas in a patient with von Hippel-Lindau disease followed for more than 20 years.

    Rosa, R H; Goldberg, M F; Green, W R

    1996-01-01

    The authors review the histopathologic findings in the eyes of a patient with multiple retinal angiomas and von Hippel-Lindau disease, who underwent treatment with argon laser photocoagulation with follow-up of more than 20 years. The patient was studied ophthalmoscopically and by fluorescein angiography before and after argon laser photocoagulation of retinal angiomas. The eyes were obtained postmortem, and the central portion of the right eye, including the macula and optic nerve head, was sectioned serially for light microscopy. The pupil-optic nerve segment of the left eye was step-sectioned serially for light microscopy. Histopathologic study of the right eye disclosed mild cystoid macular edema and focal areas of exudation in the midperiphery possibly secondary to irradiation of the head. A 1.5 x 0.3-mm area of residual angioma was present in the nasal peripapillary retina. Superotemporally, four chorioretinal scars were present in one photocoagulated area. These scars were composed of dense fibrous tissue with vascularization and variable retinal pigment epithelium hyperplasia. Large, nonangiomatous vessels within each of the scars were continuous with other retinal vessels. Inferotemporally, two chorioretinal scars were present in one photocoagulated area. Histopathologically, these scars were similar to the superotemporal scars, except that no patent retinal vessels traversed the inferotemporal scars. Neovascularization of the retina was associated with one superotemporal and one inferotemporal scar. No residual angiomatous tissue was present in the supero- or inferotemporal areas. Histopathologic examination of the left eye disclosed extensive vitreous organization and periretinal fibrovascular proliferation, extensive gliosis of the retina, and a 4.5 x 2-mm schisis cavity filled with fibrinous exudate. Three angiomas with variable fibrosis were present in the left eye. Despite a poor clinical course in one eye treated with xenon arc photocoagulation

  1. [Krypton laser photocoagulation at low power setting for age-related macular degeneration complicated with subfoveal choroidal neovascularization].

    Zhang, Cheng-fen; Jia, Yan; Li, Zhi-qing; Du, Hong; Han, Bao-ling

    2004-12-01

    To evaluate the efficacy of krypton laser photocoagulation for treatment of age-related macular degeneration (AMD) complicated with mainly subfoveal classic choroidal neovascularization (CNV). Seventeen eyes of 17 cases, aged 50 - 74 years (averaged 60.8 years) with mainly subfoveal classic choroidal neovascularization were treated with krypton laser at lower power setting. The treatment was completed in one session. Another course of treatment was given 4 weeks later if there was active leakage demonstrated at the CNV area. Visual acuity, anterior segment and fundus examination, perimetry test, fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were performed before and after treatment. The follow-up period was 3.5 years on average (1 - 8 years). There was no immediately decrease of visual acuity after treatment. All treated eyes showed absorption of hemorrhages and/or exudates and diminished leakages. Visual acuity was stable in 8 eyes; improved in 6 eyes (>/= 2 lines), and decreased in 3 eyes (Krypton laser photocoagulation at low power setting is an effective treatment for AMD with mainly classic subfoveal choroidal neovascularization.

  2. Analysis of laser photocoagulation with cataract surgery for improvement of visual acuity and macular edema in patients with cataract and diabetic macular edema

    Chao-Yu Wang

    2016-02-01

    Full Text Available AIM:To explore laser photocoagulation with cataract surgery for improvement of visual acuity and macular edema in patients with cataract and diabetic macular edema.METHODS:A total of 60 patients(72 eyesfrom January 2014 to July 2015 in our hospital were selected, which all were diagnosed as cataract with diabetic macular edema. According to a random number table method, the patients were divided into observation group and control group, 30 cases(36 eyesin each group. The observation group was treated with combination therapy of laser photocoagulation before cataract surgeries, while the control group with the combination therapy of laser photocoagulation after cataract surgeries. At 2mo after surgeries, some routine examination, such as visual acuity, fundus examination after mydriasis, slit lamp examination, optical coherence tomography(OCTexamination, fluorescence angiography examination(FFAfor retinal blood vessels were applied in all the patients. RESULTS:The visual acuity of the observation group and the control group before treatments was not significantly different(P>0.05. At 2mo after treatments, the visual inspection showed that compared with the visual acuity before treatment, the visual acuity of the two groups were both significantly improved(PPP>0.05. At 2mo after treatments, compared with those before treatments, the macular thickness of two groups were both significantly improved(PPCONCLUSION:The laser photocoagulation before cataract surgery for patients with cataract and diabetic macular edema can significantly improve their visual acuity and macular thickness.

  3. Fetofetal Transfusion Syndrome in Monochorionic-Triamniotic Triplets Treated with Fetoscopic Laser Ablation: Report of Two Cases and A Systematic Review

    Yair J. Blumenfeld

    2015-10-01

    Full Text Available Objective - This study aims to determine the clinical outcomes of monochorionic-triamniotic (MT pregnancies complicated by severe fetofetal transfusion undergoing laser photocoagulation. Study Design - We report two cases of MT triplets complicated by fetofetal transfusion syndrome (FFTS and a systematic review classifying cases into different subtypes: MT with two donors and one recipient, MT with one donor and two recipients, MT with one donor, one recipient, and one unaffected triplet. The number of neonatal survivors was analyzed based on this classification as well as Quintero staging. Results - A total of 26 cases of MT triples complicated by FFTS were analyzed. In 56% of the cases, the FFTS involved all three triplets, 50% of whom had an additional donor and 50% an additional recipient. Among the 24 cases that survived beyond 1 week after the procedure, the average gestational age of delivery was 29.6 weeks, and the average interval from procedure to delivery was 10.1 weeks. The overall neonatal survival rate was 71.7%, with demises occurring equally between donor and recipient triplets. Overall neonatal survival including survival of at least two fetuses occurred with equal frequency between the different groups. Conclusion - Significant neonatal survival can be achieved in most cases of MT triplets with FFTS.

  4. Pars plana vitrectomy with juxtapapillary laser photocoagulation versus vitrectomy without juxtapapillary laser photocoagulation for the treatment of optic disc pit maculopathy: the results of the KKESH International Collaborative Retina Study Group.

    Abouammoh, Marwan A; Alsulaiman, Sulaiman M; Gupta, Vishali S; Mousa, Ahmed; Hirakata, Akito; Berrocal, Maria H; Chenworth, Megan; Chhablani, Jay; Oshima, Yusuke; AlZamil, Waseem M; Casella, Antonio Marcelo; Papa-Oliva, Gabriela; Banker, Alay S; Arevalo, J Fernando

    2016-04-01

    To compare the functional and anatomic outcomes of pars plana vitrectomy (PPV) with juxtapapillary laser photocoagulation (JLP) versus vitrectomy without JLP in optic disc pit maculopathy. This was a multicentre, retrospective study of 46 consecutive patients with optic disc pit maculopathy presenting at tertiary eye centres between 1992 and 2012. Indications for surgery included distorted or decreased vision. Surgical intervention included PPV, posterior vitreous detachment, with or without gas tamponade. Twenty-four patients received laser photocoagulation at the temporal edge of the optic disc pit (group A) and 22 patients had no laser (group B). Postoperative best-corrected visual acuity (BCVA) and optical coherence tomography findings were the main outcome measures. Mean follow-up was 44 months (range 12-98 months). BCVA in group A improved significantly from 0.7 logMAR (20/100) preoperatively to 0.5 logMAR (20/60) postoperatively (p=0.017). In group B, BCVA improved from 0.7 logMAR (20/100) preoperatively to 0.4 logMAR (20/40) postoperatively (p=0.014). The difference in final BCVA between groups was not statistically significant (p=0.693). The mean central macular thickness (CMT) in group A improved significantly from 750 μm preoperatively to 309 μm at last follow-up (pfinal CMT between groups was not statistically significant (p=0.747). PPV with JLP for optic disc pit maculopathy had similar functional and anatomic outcomes compared with vitrectomy without JLP. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  5. Macular laser photocoagulation guided by spectral-domain optical coherence tomography versus fluorescein angiography for diabetic macular edema

    Gallego-Pinazo R

    2011-05-01

    Full Text Available Roberto Gallego-Pinazo1,2, Ana Marina Suelves-Cogollos1, Rosa Dolz-Marco1, J Fernando Arevalo3, Salvador García-Delpech1, J Luis Mullor4, Manuel Díaz-Llopis1,2,51Department of Ophthalmology, Hospital Universitario La Fe, Valencia, Spain; 2Centro de Investigación Biomédica en Red de Enfermedades Raras, Valencia, Spain; 3Retina and Vitreous Service, Clinical Ophthalmology Center, Caracas, Venezuela; 4Unit of Experimental Ophthalmology, Hospital Universitario La Fe, Valencia, Spain; 5University of Valencia, Faculty of Medicine, Valencia, SpainBackground: The aim of this study was to compare the efficacy of spectral-domain optical coherence tomography (SD-OCT and fluorescein angiography (FA in the guidance of macular laser photocoagulation for diabetic macular edema.Methods: This was a prospective interventional clinical comparative pilot study. Forty eyes from 24 consecutive patients with diabetic macular edema were allocated to receive laser photocoagulation guided by SD-OCT or FA. Best-corrected visual acuity (BCVA, central macular thickness, and retinal volume were assessed at baseline and two months after treatment.Results: Subjects treated using FA-guided laser improved BCVA from the logarithm of the minimum angle of resolution (logMAR 0.52 ± 0.2 to 0.37 ± 0.2 (P < 0.001, and decreased mean central macular thickness from 397.25 ± 139.1 to 333.50 ± 105.7 µm (P < 0.001 and retinal volume from 12.61 ± 1.6 to 10.94 ± 1.4 mm3 (P < 0.001. Subjects treated using SD-OCT guided laser had improved BCVA from 0.48 ± 0.2 to 0.33 ± 0.2 logMAR (P < 0.001, and decreased mean central macular thickness from 425.90 ± 149.6 to 353.4 ± 140 µm (P < 0.001 and retinal volume from 12.38 ± 2.1 to 11.53 ± 1.1 mm3 (P < 0.001. No significant differences between the groups were found in two-month BCVA (P = 0.505, two-month central macular thickness (P = 0.660, or two-month retinal volume (P = 0.582.Conclusion: The short-term results of this pilot study

  6. Clinical analysis of laser photocoagulation for diabetic retinopathy%糖尿病视网膜病变激光光凝治疗疗效分析

    张志红; 王媛媛; 曹江欣

    2013-01-01

    目的探讨激光光凝治疗糖尿病视网膜病变(DR)的疗效。方法 以DR患者54例108眼为研究对象,对增殖期(PDR)96眼行标准全视网膜光凝,非增殖期(NPDR)22眼行弥漫视网膜光凝。结果 视力提高或不变90眼,有效率83.3%。FFA检查示有效率86.1%。结论 激光光凝术是治疗DR 的一个有效方法,要把握光凝时机,争取早期发现并及时治疗DR,提高激光光凝的疗效。%Objective :To evaluate the efficacy of laser coagulation for diabetic retinopathy. Method :Total 54 patients (108 eyes) of diabetic retinopathy were as the object of this study. 96 eyes with proliferative diabetic retinopathy (PDR) were given panretinal photocoagulation. 22 eyes with non-proliferative diabetic retinopathy(NPDR)were given scatter photocoagulation.Results : the eyes of vision improve or no change are 90,totle effective rate is 83.3. totle effective rate of FFA examination is 86.1%. Conclusion: Laser photocoagulation is an effective method for diabetic retinopathy. It has different efficacy for the different stages of diabetic retinopathy. It can improve the efficacy of laser photocoagulation that we seize the opportunity of laser photocoagulation for diabetic retinopathy,early detecting and timely treating diabetic retinopathy.

  7. The combined use of surgical debulking and diode laser photocoagulation for limbal melanoma treatment: a retrospective study of 21 dogs.

    Andreani, Valentina; Guandalini, Adolfo; D'Anna, Nunzio; Giudice, Chiara; Corvi, Roberta; Di Girolamo, Nicola; Sapienza, John S

    2017-03-01

    To evaluate effectiveness and safety of debulking and diode laser photocoagulation (DPC) for the treatment of limbal melanoma (LM). Retrospective multi-institutional case series. Medical records of animals diagnosed with LM at the Centro Veterinario Specialistico (CVS) and at the Long Island Veterinary Specialists from 1994 to 2014 were retrieved. Signalment, location, extent of tumors, recurrence rate, and early and late complications were reported. Patient follow-up information was obtained from veterinary ophthalmologists, primary care veterinarians, and where appropriate, owners. Twenty-one eyes of 21 dogs (13 females and 8 males) were included in this study. The dogs' average age was 6 years (range: 7 months-11 years). The follow-up period ranged from 1-108 months (median 48 months) after the last DPC procedure. Long-term follow-up was obtained by telephone interviews in 6 of 20 cases and by clinical re-evaluations in 14 of 20 cases. The most common early complications were a moderate anterior uveitis and peripheral corneal edema (21/21 eyes). Late complications included corneal fibrosis and/or pigmentation (20/21). In one case, a severe bullous keratopathy associated with extensive corneal fibrosis was observed (1/21). One case was blind due to concurrent Sudden Acquired Retinal Degeneration (SARD). However, after surgery 2 of 20 eyes lost vision and one of these was enucleated. Debulking, in addition to diode laser photocoagulation, was technically straightforward to perform, minimally invasive, well tolerated, and highly successful in this case series. © 2016 American College of Veterinary Ophthalmologists.

  8. Comparison of Pain Response of Patients Undergoing Panretinal Photocoagulation for Proliferative Diabetic Retinopathy: 532 nm Standard Laser vs. Multispot Pattern Scan Laser

    Göktuğ Seymenoğlu

    2013-08-01

    Full Text Available Purpose: To compare pain response of patients undergoing panretinal photocoagulation (PRP for proliferative diabetic retinopathy (PDR using 532 nm standard laser versus multispot pattern scan laser and to evaluate the relationship between pain response and patient characteristics. Material and Method: Thirty-five patients had PRP with the Pascal system in a single session, while other 35 patients had PRP with conventional laser in 2 sessions. Parameters used in conventional laser were as follows: spot size 200 µm, exposure time 0.2 s, and power sufficient to produce visible grey-white burns. We used same spot size, 20-30 ms exposure time, and higher levels of laser power in order to get a similar endpoint in the Pascal system. The patients were required to evaluate the severity of pain on a visual analog scale (VAS and verbally 5 minutes after PRP with Pascal and 5 minutes after the first session of PRP with conventional laser. The relationship between pain experienced and patient characteristics was evaluated. Results: At baseline, both groups did not differ significantly (p >0.05, for all with respect to sex, age, duration of diabetes, most recent HbA1c, treatment regimen, or patient experience. The patients in the Pascal group had a mean pain score of 0.55±0.70 on verbal scale and 1.54±1.22 on VAS compared to 2.17±1.18 and 5.54±3.28, respectively in the conventional laser group which was, statistically, significantly different in both scales (p<0.05. Discussion: Our study confirms that new generation pattern scanning photocoagulators satisfactorily decrease the pain by shortening the exposure time while increasing the laser power. (Turk J Ophthalmol 2013; 43: 221-4

  9. Long-term result of out-patient neodymium-doped yttrium aluminium garnet laser photocoagulation surgery for patients with epistaxis.

    Zhang, J; Qiu, R; Wei, C

    2016-01-01

    To evaluate the long-term efficacy of out-patient neodymium-doped yttrium aluminium garnet laser photocoagulation surgery for patients with epistaxis. A retrospective clinical study was conducted. A total of 217 consecutive patients who presented with acute or recurrent epistaxis received neodymium-doped yttrium aluminium garnet laser photocoagulation treatment in an out-patient setting. At three years, 94 per cent of acute epistaxis patients versus 88 per cent of recurrent epistaxis patients reported no bleeding. The outcome scores at 12 weeks and 3 years after treatment showed no significant differences between the 2 groups (p = 0.207 and p = 0.186). However, there was a significant difference in outcome scores at four weeks after treatment (p = 0.034). The median (and mean ± standard deviation) pain levels experienced during the laser operation (performed in an office setting) were 4.0 (3.75 ± 2.09) in the acute epistaxis group and 4.0 (3.83 ± 2.01) in the recurrent epistaxis group. Neither group had any complications. Neodymium-doped yttrium aluminium garnet laser photocoagulation is desirable in the treatment of both acute and recurrent epistaxis, and has long-lasting efficacy.

  10. Microperimetry and fundus autofluorescence in diabetic macular edema: subthreshold micropulse diode laser versus modified early treatment diabetic retinopathy study laser photocoagulation.

    Vujosevic, Stela; Bottega, Elisa; Casciano, Margherita; Pilotto, Elisabetta; Convento, Enrica; Midena, Edoardo

    2010-06-01

    The purpose of this study was to evaluate and compare microperimetry and fundus autofluorescence (FAF) after subthreshold micropulse diode laser versus modified Early Treatment Diabetic Retinopathy Study photocoagulation for clinically significant diabetic macular edema. A prospective randomized clinical trial including 62 eyes (50 patients) with untreated, center-involving, clinically significant diabetic macular edema was performed. All patients underwent best-corrected visual acuity determination (logarithm of the minimum angle of resolution), slit-lamp biomicroscopy, FAF, optical coherence tomography, microperimetry (macular sensitivity), and fluorescein angiography before and after treatment. Best-corrected visual acuity, optical coherence tomography, microperimetry, and FAF were repeated at 1-, 3-, 6-, 9-, and 12-month follow-up examinations. Fluorescein angiography was performed at baseline and at 6 and 12 months. Before treatment, demographic and macular parameters were not different between the two treatment groups. At 12 months, best-corrected visual acuity remained stable in both groups (P = 0.41 and P = 0.82), mean central retinal thickness decreased in both groups (P = 0.0002 and P autofluorescence never changed in the micropulse diode laser group even after retreatment. In the Early Treatment Diabetic Retinopathy Study group, FAF increased up to 9 months and decreased in 6 eyes (20%) at 12 months. Micropulse diode laser seems to be as effective as modified Early Treatment Diabetic Retinopathy Study laser photocoagulation in the treatment of clinically significant diabetic macular edema. Micropulse diode laser treatment does not determine any change on FAF showing (at least) nonclinically visible damage of the retinal pigment epithelium. Microperimetry data encourage the use of a new, less aggressive laser therapeutic approach in the treatment of clinically significant diabetic macular edema.

  11. Comparison of the neuroinflammatory responses to selective retina therapy and continuous-wave laser photocoagulation in mouse eyes.

    Han, Jung Woo; Choi, Juhye; Kim, Young Shin; Kim, Jina; Brinkmann, Ralf; Lyu, Jungmook; Park, Tae Kwann

    2018-02-01

    This study investigated microglia and inflammatory cell responses after selective retina therapy (SRT) with microsecond-pulsed laser in comparison to continuous-wave laser photocoagulation (cwPC). Healthy C57BL/6 J mice were treated with either a train of short pulses (SRT; 527-nm, Q-switched, 1.7-μs pulse) or a conventional thermal continuous-wave (532-nm, 100-ms pulse duration) laser. The mice were sacrificed and their eyes were enucleated 1, 3, 7, and 14 days after both laser treatments. Pattern of cell death on retinal section was evaluated by TUNEL assay, and the distribution of activated inflammatory cells and glial cells were observed under immunohistochemistry. Consecutive changes for the expression of cytokines such as IL-1β, TNF-α, and TGF-β were also examined using immunohistochemistry, and compared among each period after quantification by Western blotting. The numbers of TUNEL-positive cells in the retinal pigment epithelium (RPE) layer did not differ in SRT and cwPC lesions, but TUNEL-positive cells in neural retinas were significantly less on SRT. Vague glial cell activation was observed in SRT-treated lesions. The population of inflammatory cells was also significantly decreased after SRT, and the cells were located in the RPE layer and subretinal space. Proinflammatory cytokines, including IL-1β and TNF-α, showed significantly lower levels after SRT; conversely, the level of TGF-β was similar to the cwPC-treated lesion. SRT resulted in selective RPE damage without collateral thermal injury to the neural retina, and apparently produced negligible glial activation. In addition, SRT showed a markedly less inflammatory response than cwPC, which may have important therapeutic implications for several macular diseases.

  12. Efficacy of intravitreal injection of Ranibizumab combined with laser photocoagulation in treatment of macular edema secondary to branch retina vein occlusion

    Rui-Fang Yang

    2016-01-01

    Full Text Available AIM:To observe the effect and safety of Ranibizumab intravitreal injection combined with laser photocoagulation in treatment of macular edema secondary to branch retina vein occlusion(BRVO.METHODS:Forty-four patients(44 eyeswith macular edema secondary to BRVO were enrolled. Patients received intravitreal injection of ranibizumab(0.05mL/0.5mgand laser photocoagulation(ranibizumab groupor laser photocoagulation alone(control group. Patients in ranibizumab group were given laser photocoagulation at 1mo after intravitreal injection. Then ranibizumab was given again if needed. The best corrected visual acuity(BCVA, slitlamp examination, fundus examination, non-contact tonometer examination and fundus fluorescein angiography were taken. All patients were followed up for 6mo. We analyzed the changes on BCVA,central macular thickness(CMTbefore and 1,4,12 and 24wk after treatments, and related complications were recorded. RESULTS:Outcomes are significantly better in ranibizumab group with reduced retinal thickness and improved visual acuity. In ranibizumab group, both visual acuity and CMT values were significantly better than those before treatments(visual acuity:t=5.781,7.496,7.341,7.836, all P=0.000; CMT:t=9.784,11.893,11.573,11.437, all P=0.000.In control group, the improvement on visual acuity was not significantly better than that before treatment at 1wk(t=2.130,P=0.053; while the improvement on visual acuity was significantly better at 4,12 and 24wk(t=3.524,6.429,6.922,P=0.04,0.000,0.000.The improvements on visual acuity after treatments in ranibizumab group were significantly better than those in control group at 1,4,12 and 24wk(t=2.604,3.223,3.303,3.296,P=0.015,0.03,0.04,0.03.CMT values after treatments in ranibizumab group were significantly better than those in contral group at 1,4,12 and 24wk(t=43.231,50.504,56.074,38.103,all P=0.000.No severe ocular and systematic side effect was found.CONCLUSION:Intravitreal injection of ranibizumab

  13. Clinical observation of one time short-pulse pattern scan laser pan-retinal photocoagulation for proliferative diabetic retinopathy

    Xin Liu

    2016-04-01

    Full Text Available AIM: To investigate the clinical efficacy and benefit of short-pulse pattern scan laser(PASCALphotocoagulation for proliferative diabetic retinopathy(PDR.METHODS:Twenty-eight PDR patients(42 eyesunderwent short-pulse PASCAL pan-retinal photocoagulation(PRPwere analyzed.The best corrected visual acuity was ≥0.1 in 36 eyes, RESULTS: All the cases had no pain during the short-pulse PASCAL treatment.One year after treatments,the final visual acuity was improved in 6 eyes,kept stable in 28 eyes and decreased in 8 eyes; neovascularization were regressed in 18 eyes(43%, stable in 12 eyes(29%, uncontrolled in 12 eyes(29%. Five eyes(12%received vitrectomy due to vitreous hemorrhage.Compared with before operation, retina thickness in central fovea of macula and visual field had no obvious change after one-time PASCAL PRP(P>0.05. CONCLUSION:The one-time short-pulse PASCAL PRP could stabilize the progress of PDR safely, effectively and simply.

  14. Dynamic contrast enhanced CT measurement of blood flow during interstitial laser photocoagulation: comparison with an Arrhenius damage model

    Purdie, T.J.; Lee, T.J.; Iizuka, M.; Sherar, M.D.

    2000-01-01

    One effect of heating during interstitial laser photocoagulation (ILP) is to directly destroy the tumour vasculature resulting in a loss of viable blood supply. Therefore, blood flow measured during and after treatment can be a useful indicator of tissue thermal damage. In this study, the effect of ILP treatment on rabbit thigh tumours was investigated by measuring blood flow changes using dynamic contrast enhanced computed tomography (CT). The CT measured changes in blood flow of treated tumour tissue were fitted to an Arrhenius model assuming first order rate kinetics. Our results show that changes in blood flow of tumour tissue distant from surrounding normal tissue are well described by an Arrhenius model. By contrast, the temperature profile of tumour tissue adjacent to normal tissue must be modified to account for heat dissipation by the latter. Finally, the Arrhenius parameters derived in the study are similar to those derived by heating tumour tissue to a lower temperature (<47 deg. C) than the current study. In conclusion, CT can be used to monitor blood flow changes during ILP and these measurements are related to the thermal damage predicted by the Arrhenius model. (author)

  15. Long-term efficacy of Nd:YAG laser photocoagulation vs. liquid paraffin plus antiseptic cream in the treatment of recurrent epistaxis.

    Zhang, Jing; Qiu, Rongxing; Wei, Chunsheng

    2015-12-01

    The objective of this study was to evaluate the long-term efficacy of Nd:YAG laser photocoagulation with that of liquid paraffin plus antiseptic cream in the management of recurrent epistaxis. Eighty consecutive patients who suffered from recurrent anterior epistaxis presented to the Otolaryngology Department at the Eye and ENT Hospital, Fudan University between February 2011 and June 2011. These patients with histories of recurrent epistaxis were randomly assigned to receive treatment in an outpatient setting consisting of either a combination of liquid paraffin plus antiseptic cream (Group 1) or Nd:YAG laser photocoagulation (Group 2). the following outcome measures were assessed: bleeding intensity; bleeding frequency 2 years after treatment (0 = no bleeding, 1 = reduced bleeding, 2 = the same, 3 = worse), participant's perception of discomfort during the management (grade 0-10, where 10 is the worst pain), and complications. Finally, 70 patients remain in our study. At 2 years, 86 % of laser patients versus 31 % of control patients had no reported bleeding. The outcome score at 2 years after treatment showed a significant difference between the two groups (P = 0.000, P < 0.01). The median and mean ± SD pain levels experienced were 5.0 and 5.2 ± 2.2. Both groups had no complications. It can be further concluded that Nd:YAG laser photocoagulation is a preferable therapy in the treatment of recurrent epistaxis in long-term efficacy. The level of pain associated with the procedure was well tolerated. It is a simple, easy, safe and rapid therapy, which can be performed in an office setting.

  16. Translimbal laser photocoagulation to the trabecular meshwork as a model of glaucoma in rats.

    Levkovitch-Verbin, Hana; Quigley, Harry A; Martin, Keith R G; Valenta, Danielle; Baumrind, Lisa A; Pease, Mary Ellen

    2002-02-01

    To develop and characterize a model of pressure-induced optic neuropathy in rats. Experimental glaucoma was induced unilaterally in 174 Wistar rats, using a diode laser with wavelength of 532 nm aimed at the trabecular meshwork and episcleral veins (combination treatment group) or only at the trabecular meshwork (trabecular group) through the external limbus. Intraocular pressure (IOP) was measured by a tonometer in rats under ketamine-xylazine anesthesia. Possible retinal vascular compromise was evaluated by repeated fundus examinations and by histology. The degree of retinal ganglion cell (RGC) loss was assessed by a masked, semiautomated counting of optic nerve axons. Effects of laser treatment on anterior ocular structures and retina were judged by light microscopy. After the laser treatment, IOP was increased in all eyes to higher than the normal mean IOP of 19.4 +/- 2.1 mm Hg (270 eyes). Peak IOP was 49.0 +/- 6.1 mm Hg (n = 108) in the combination group that was treated by a laser setting of 0.7 seconds and 0.4 W and 34.0 +/- 5.7 mm Hg (n = 46) in the trabecular group. Mean IOP after 6 weeks was 25.5 +/- 2.9 mm Hg in glaucomatous eyes in the combination group compared with 22.0 +/- 1.8 mm Hg in the trabecular group. IOP in the glaucomatous eyes was typically higher than in the control eyes for at least 3 weeks. In the combination group, RGC loss was 16.1% +/- 14.4% at 1 week (n = 8, P = 0.01), 59.7% +/- 25.7% at 6 weeks (n = 88, P < 0.001), and 70.9% +/- 23.6% at 9 weeks (n = 12, P < 0.001). The trabecular group had mean axonal loss of 19.1% +/- 14.0% at 3 weeks (n = 9, P = 0.004) and 24.3% +/- 20.2% at 6 weeks (n = 25, P < 0.001), increasing to 48.4% +/- 32.8% at 9 weeks (n = 12, P < 0.001). Laser treatment led to closure of intertrabecular spaces and the major outflow channel. The retina and choroid were normal by ophthalmoscopy at all times after treatment. Light microscopic examination showed only loss of RGCs and their nerve fibers. Increased IOP caused

  17. Long-term outcome following interstitial laser photocoagulation of benign cold thyroid nodules

    Døssing, Helle; Bennedbæk, Finn Noe; Hegedüs, Laszlo

    2011-01-01

    discomfort were assigned to ILP. ILP (using one laser fiber) was performed under continuous ultrasound (US) guidance and with an output power of 1.5-3.5 W. Thyroid nodule volume was assessed by US and thyroid function determined by routine assays, before and during follow-up. Pressure symptoms and cosmetic...... complaints were evaluated on a visual analogue scale (0-10 cm). Of the total patients, six had thyroid surgery 6 months after ILP and three were lost to follow-up. The median follow-up for the remaining 69 patients was 67 months (range 12-114). Results The overall median nodule volume decreased from 8.2 ml...

  18. Laser photocoagulation - eye

    ... an eye disorder that slowly destroys sharp, central vision A tear in the retina A blockage of the small veins that carry ... Since parts of the retina are burned, you may develop: Mild loss ... vision If not treated, diabetic retinopathy can cause permanent ...

  19. Estudo experimental da aplicação retiniana do laser infravermelho via transescleral sob condições de baixa visibilidade Transscleral infrared laser retinal photocoagulation experimental study under low visibility conditions

    Dario Grechi Goulart

    2008-06-01

    Full Text Available OBJETIVOS: Pesquisa experimental, com laser de diodo infravermelho, para estimar a segurança, a reprodutibilidade e a permeabilidade da parede ocular à sua atuação clínica, quando aplicado via transescleral, em condições de baixa visibilidade. MÉTODOS: Submetemos olhos de coelhos pigmentados da raça Nova Zelândia à fotocoagulação retiniana por laser de diodo infravermelho. No olho direito, realizamos fotocoagulação via transescleral sob parâmetros de potência e tempo pré-determinados clinicamente. No olho esquerdo, foram repetidos os mesmos valores da potência e tempo usados no olho direito, desta vez, via transpupilar. Imediatamente e após 2 meses, estudos clínicos baseados na retinografia e histopatológicos foram realizados. RESULTADOS: A permeabilidade da parede ocular, quando da aplicação do laser de diodo infravermelho via transescleral, variou entre 58,95 e 63,87%. A média da permeabilidade da parede ocular a 300 mW (63,14% mostrou-se significativamente superior àquela da permeabilidade da parede ocular encontrada a 500 mW (59,11%, (PPURPOSE: Retinal photocoagulation under poor visualization condition is often required. Transscleral infrared laser can be used as an alternative to regular transpupillary treatment. Based upon retinographic measurements, we proposed to estimate the reproducibility as well as ocular wall permeability rate for this treatment. Our primary goal was to evaluate whether this technique can deliver adequate photocoagulation at predetermined parameters without direct retinal visualization. METHODS: In New Zealand pigmented rabbits, optimal transscleral infrared diode laser settings were administered to the right eye. With the same parameters, transpupillary photocoagulation was repeated in the left eye. Retinographic and clinical examinations were performed immediately and two months later. RESULTS: Ocular wall permeability rate varied between 58.95 and 63.87%. Average permeability using a

  20. Clinical Abservation of Krypton Laser Photocoagulation Preventing Retinal Detachment after LASIK on High Myopia%眼底激光预防中高度近视LASIK术后视网膜脱离的临床观察

    周建平; 胡莉群; 胡长青

    2014-01-01

    目的观察LASIK术前对中高度近视患者行预防性眼底激光光凝的疗效。方法准备接受LASIK手术的中高度近视患者作详细眼底检查,直接眼底镜、间接眼底镜和三面镜检查明确有视网膜变性或(和)干性裂孔的患者共61例(112眼)行氪激光光凝治疗。结果61例(112眼)患者氪激光光凝术后变性区及裂孔封闭良好,未发生视网膜脱离。结论对明确有视网膜变性和裂孔的中高度近视患者LASIK术前行氪激光光凝是预防LASIK术后发生孔源性视网膜脱离的一种安全有效的方法。%Objective To observe the effect of krypton laser photocoagulation before LASIK on high myopia. Methods Full fundus examination on high myopic patients was performed with direct ophthalmoscopy, indirect ophthalmoscopy and three mirror contact lens. 112 eyes of 61 patients with peripheral retinal degeneration or retinal hole were treated by krypton laser photocoagulation before LASIK. Results 112 eyes of 61 patients with peripheral retinal degeneration or retinal hole were stable after krypton laser photocoagulation.No retinal detachment was occurred. Conclusion The krypton laser photocoagulation is a safe and ef ective method to preventing retinal detachment for the patients with peripheral retinal degeneration or retinal hole.

  1. Efficacy and safety of green laser photocoagulation for threshold retinopathy of prematurity Eficácia e segurança da fotocoagulação com laser verde na retinopatia da prematuridade limiar

    Rodrigo Pessoa Cavalcanti Lira

    2008-02-01

    Full Text Available PURPOSE: To report the efficacy and safety of green laser photocoagulation for threshold retinopathy of prematurity (ROP. METHODS: We reviewed the clinical records of the neonates who had undergone green laser photocoagulation for threshold ROP at the Federal University of Pernambuco in Brazil between January 2004 and January 2006. All procedures were conducted with local anesthetic drops. The neonates were monitored throughout the procedure by a neonatologist. A frequency-doubled solid state laser, diode-pumped, with 532 nm wavelength was used. The presence of tunica vasculosa lentis or cataract were excluded before laser treatment. The following preoperative data were obtained for each patient: age, birth weight and the grade of ROP. Postoperative data included complications associated with the laser treatment, grade of ROP and evaluation whether further surgery was necessary due to failure of laser photocoagulation. RESULTS: Twenty-two neonates underwent photocoagulation with green laser for threshold ROP. A total of 31 eyes were included in the study. The mean gestational age was 30 ± 3 weeks and the mean birth weight was 1120 ± 490 g. Regression of the disease after laser therapy was observed in 30 eyes (96.7%. Despite treatment one eye presented stage 4A. Only 7 eyes required repetitive laser therapy. No adverse effects such as burning anterior segment tissues or bleeding in the anterior chamber occurred. No posterior segment side-effects were observed. Cataract formation was not observed at the last follow-up examination. CONCLUSIONS: Green laser photocoagulation remains an effective and safe alternative to red laser photocoagulation and to cryotherapy in the treatment of threshold ROP.OBJETIVOS: Avaliar a eficácia e segurança da fotocoagulação com laser verde na retinopatia da prematuridade (ROP limiar. MÉTODOS: Foram revisados prontuários dos neonatos submetidos à fotocoagulação com laser verde para ROP limiar, na

  2. Efficiency and safety of laser photocoagulation with or without intravitreal ranibizumab for treatment of diabetic macular edema: a systematic review and Meta-analysis

    Tian-Wei Qian

    2017-07-01

    Full Text Available AIM: To compare the therapeutic effect and safety of laser photocoagulation along with intravitreal ranibizumab (IVR versus laser therapy in treatment of diabetic macular edema (DME. METHODS: Pertinent publications were identified through comprehensive searches of PubMed, EMBASE, Web of Science, Cochrane Library, and ClinicalTrials.gov to identify randomized clinical trials (RCTs comparing IVR+laser to laser monotherapy in patients with DME. Therapeutic effect estimates were determined by weighted mean differences (WMD of change from baseline in best corrected visual acuity (BCVA and central retinal thickness (CRT at 6, 12, or 24mo after initial treatment, and the risk ratios (RR for the proportions of patients with at least 10 letters of improvement or reduction at 12mo. Data regarding major ocular and nonocular adverse events (AEs were collected and analyzed. The Review Manager 5.3.5 was used. RESULTS: Six RCTs involving 2069 patients with DME were selected for this Meta-analysis. The results showed that IVR+laser significantly improved BCVA compared with laser at 6mo (WMD: 6.57; 95% CI: 4.37-8.77; P<0.00001, 12mo (WMD: 5.46; 95% CI: 4.35-6.58; P<0.00001, and 24mo (WMD: 3.42; 95% CI: 0.84-5.99; P=0.009 in patients with DME. IVR+laser was superior to laser in reducing CRT at 12mo from baseline with statistical significance (WMD: -63.46; 95% CI: -101.19 to -25.73; P=0.001. The pooled RR results showed that the proportions of patients with at least 10 letters of improvement or reduction were in favor of IVR+laser arms compared with laser (RR: 2.13; 95% CI: 1.77-2.57; P<0.00001 and RR: 0.37; 95% CI: 0.22-0.62; P=0.0002, respectively. As for AEs, the pooled results showed that a significantly higher proportion of patients suffering from conjunctival hemorrhage (study eye and diabetic retinal edema (fellow eye in IVR+laser group compared to laser group (RR: 3.29; 95% CI: 1.53-7.09; P=0.002 and RR: 3.02; 95% CI: 1.24-7.32; P=0.01, respectively. The

  3. Efficacy of anti-VEGF and laser photocoagulation in the treatment of visual impairment due to diabetic macular edema: a systematic review and network meta-analysis.

    Stephane Régnier

    Full Text Available Compare the efficacy of ranibizumab, aflibercept, laser, and sham in the first-line treatment of diabetic macular edema (DME to inform technology assessments such as those conducted by the UK National Institute for Health and Care Excellence (NICE.MEDLINE, Embase, Cochrane Library, congress abstracts, ClinicalTrials.gov registry and Novartis data on file.Studies reporting 6- or 12-month results of randomized controlled trials (RCTs evaluating at least two of ranibizumab 0.5 mg pro re nata, aflibercept 2.0 mg bi-monthly, laser photocoagulation or sham. Study quality was assessed based on likelihood of bias in selection, attrition, detection and performance.Improvement in best-corrected visual acuity (BCVA measured as the proportion of patients gaining ≥10 letters on the Early Treatment Diabetic Retinopathy Study scale. The outcome was chosen following acceptance by NICE of a Markov model with 10-letter health states in the assessment of ranibizumab for DME.Bayesian network meta-analyses with fixed and random effects adjusted for differences in baseline BCVA or central retinal thickness.The analysis included 1,978 patients from eight RCTs. The random effects model adjusting for baseline BCVA was the best model based on total residual. The efficacy of ranibizumab was numerically, but not statistically, superior to aflibercept (odds ratio [OR] 1.59; 95% credible interval [CrI], 0.61-5.37. Ranibizumab and aflibercept were statistically superior to laser monotherapy with ORs of 5.50 (2.73-13.16 and 3.45 (1.62-6.84 respectively. The probability that ranibizumab is the most efficacious treatment was 73% compared with 14% for aflibercept, 12% for ranibizumab plus laser, and 0% for laser.Three of the eight RCTs included are not yet published. The models did not adjust for all potential effect modifiers.Ranibizumab was non-significantly superior to aflibercept and both anti-VEGF therapies had statistically superior efficacy to laser.

  4. Intravitreal anti-VEGF therapy as an adjunct to laser photocoagulation for severe aggressive posterior retinopathy of prematurity

    Sengul Ozdek

    2013-01-01

    Conclusion: The association of IVB and laser ablation might decrease the progression rate in severe AP-ROP. Prompt regression of iris neovascularization encourages its use in cases with pupillary rigidity to allow for laser treatment. When used as a salvage therapy it may not change the overall result dramatically.

  5. Photocoagulation treatment of radiation retinopathy

    Kinyoun, J.L.; Chittum, M.E.; Wells, C.G.

    1988-01-01

    We studied the visual and anatomic effects of focal photocoagulation for clinically significant radiation macular edema in five eyes of four patients and panretinal photocoagulation for proliferative radiation retinopathy in six eyes of three patients. Focal and limited scatter photocoagulation was successful in preventing further vision loss in all five eyes treated for macular edema. Three eyes treated with panretinal photocoagulation had regression of neovascularization. The other three eyes treated for proliferative retinopathy subsequently had dense vitreous hemorrhages that required vitrectomy for restoration of useful vision

  6. Interstitial laser photocoagulation in the treatment of liver tumors. Personal technique, short term results and complications in patients with normal and impaired liver function; Fotocoagulazione laser-interstiziale ecoguidata dei tumori maligni del fegato: tecnica personale, risultati immediati e complicanze a breve termine nei pazienti con funzionalita' epatica normale e alterata

    Giorgio, A.; Tarantino, L.; De Stefano, G.; Farella, N. [Azienda Ospedaliera D. Cotugno, Naples (Italy). Servizio di Ecografia ed Ecointerventistica; Catalano, O.; Cusati, B. [Ospedale S. Maria delle Grazie, Pozzuoli, NA (Italy). Servizio di Radiologia; Alalia, A. [Azienda Ospedaliera D. Cotugno, Naples (Italy). Servizio di Anestesia e Rianimazione; Del Vescovo, L. [Naples Univ. II, Naples (Italy). Ist. di Radiologia

    2000-04-01

    The work reports the personal experience with interstitial laser photocoagulation in patients with liver tumors (mostly cirrhotics with hepatocellular carcinoma). The aim was to evaluate the short term efficacy of percutaneous interstitial laser photocoagulation in inducing focal ablation of liver tumors and the possible complications in patients with normal and impaired liver function. [Italian] Il presente lavoro riporta l'esperienza personale con l'utilizzazione della fotocoagulazione laser-interstiziale per tumori maligni del fegato, rappresentati in gran parte da epatocarcinomi in cirrosi. Lo scopo e' quello di verificare l'efficacia terapeutica in termini di volume di necrosi e di valutare gli effetti collaterali e le complicanze a breve termine sulla riserva funzionale del fegato e di altri organi, soprattutto nei pazienti con alterata funzionalita' epatica.

  7. Comparison of Intravitreal Bevacizumab, Intravitreal Ranibizumab and Laser Photocoagulation for Treatment of Type 1 Retinopathy of Prematurity in Turkish Preterm Children.

    Kabataş, Emrah Utku; Kurtul, Bengi Ece; Altıaylık Özer, Pınar; Kabataş, Naciye

    2017-07-01

    To evaluate effectiveness of treatment modalities, major complications and refractive errors in children who were treated with intravitreal bevacizumab (IVB), intravitreal ranibizumab (IVR) or laser photocoagulation (LP) for type 1 retinopathy of prematurity (ROP). Premature infants who underwent IVB monotherapy (Group 1), IVR monotherapy (Group 2) or LP (Group 3) for type 1 ROP and infants with spontaneously regressed ROP (Group 4) were included for the study. Major complications, recurrence rate, recurrence time, total retinal vascularization time and refractive errors at 18 months of corrected age (CA) were determined. Groups 1, 2, 3 and 4 included 24 eyes of 12 patients, 12 eyes of six patients, 72 eyes of 36 patients and 148 eyes of 74 patients, respectively. Recurrence of the disease occurred in two eyes of one patient in Group 1 at 52 weeks of postmenstrual age (PMA) and two eyes of one patient at 48 weeks of PMA in Group 2. In Group 3, disease did not regress after the first treatment in 10 eyes of five patients. The mean vascularization time in Group 1 was 73 ± 10.1 weeks of PMA and 61.8 ± 6.6 weeks of PMA in Group 2 (p = 0.027). Macular ectopia was seen in two eyes of one patient and exudative retinal detachment (ERD) occurred in two eyes of one patient in Group 3. Mean spherical equivalent was 1.49 ± 3.04 diopters (D) in Group 1, -1.79 ± 2.87D in Group 2, -1.27 ± 2.8 D in Group 3 and 1.52 ± 1.07 D in Group 4 at 18 months of CA. There was no significant difference in astigmatism values in all groups. IVB, IVR and LP are options that can successfully treat ROP. Myopia was observed to be the main refractive error in all treatment groups. Vascularization of the retina was completed later in the IVB group than in the IVR group.

  8. Retinal hemodynamic influence of compound xueshuantong capsule on nonproliferative diabetic retinopathy after laser photocoagulation%复方血栓通对NPDR激光光凝术后的视网膜血流动力学影响

    王禹燕; 刘映霞; 麦少云; 邱建文; 李岚

    2014-01-01

    AlM: To observe retinal hemodynamic influence of compound xueshuantong capsule on nonproliferative diabetic retinopathy ( NPDR) after laser photocoagulation.METHODS:A total of 41 patients (72 eyes) with NPDR after laser photocoagulation were enrolled in this study. They were all given compound xueshuantong capsule, and used color Doppler flow imaging for detection of retinal hemodynamics. RESULTS: After treatment, patients with retinal blood perfusion significantly improved; central retinal arterial peak systolic velocity ( PSV ) , end - diastolic velocity (EDV) and medial velocity (Vm) were increased, while the resistance index ( Rl) decreased. The difference have statistical significance (P CONCLUSlON: Compound xueshuantong capsule can improve retinal blood perfusion for nonproliferative diabetic retinopathy after laser photocoagulation, which is related to improvement of visual prognosis.%目的:观察复方血栓通对非增生性糖尿病性视网膜病变( nonproliferative diabetic retinopathy,NPDR)激光光凝术后的视网膜血流动力学的影响。  方法:选取已行激光光凝术后的NPDR患者41例72眼,给予复方血栓通治疗,于治疗前后,采用彩色多普勒血流检测仪检测视网膜血流动力学情况。  结果:治疗后患眼视网膜血流灌注有明显改善,视网膜中央动脉的收缩期峰值血流速度( PSV)、舒张末期血流速度( EDV)和平均血流速度( Vm)均增高,而阻力指数( RI)降低,差异有统计学意义(P  结论:复方血栓通对NPDR激光光凝术后患者的视网膜血流灌注有明显改善,并且这种改善和患者视力预后的改善密切相关。

  9. Photocoagulation in the treatment of bleeding peptic ulcer

    Otto, Wlodzimierz; Paczkowski, Pawel M.

    1996-03-01

    The authors present their experience in the endoscopic laser photocoagulation of bleeding peptic ulcer. From 1991 to June 1995, 203 patients admitted for UGI bleeding from peptic ulcer have been treated by this method. The source of bleeding was confirmed by endoscopy. The patients were divided into two groups: actively bleeding peptic ulcer (group IA and IB according to Forrest's classification) and ulcer with stigmata of recent bleeding (group IIA/IIB). The former group consisted of 106 patients, among whom over 40 percent (45 patients) presented signs of hypovolemic shock on admission. Nd:YAG laser (Surgical Laser Technologies) was used in a continuous mode with a contact (8 - 20 watts) or non-contact (over 50 watts) method of coagulation. In actively bleeding patients photocoagulation resulted in stopping the hemorrhage in 95 (90%). Recurrent bleeding occurred in 16 cases; in 9 of them it was stopped by repeated photocoagulation. In this group 18 patients required surgical intervention. The mortality was of 10.3% (11 patients). In 97 patients with recent bleeding stigmata photocoagulation provoked heavy hemorrhage in 3 (in 2 cases stopped by prolonged coagulation). In 9 of the remaining 94 patients recurrent bleeding occurred. Nine patients required surgical intervention. Mortality in this group was of 6%.

  10. Ocular pulse amplitude after panretinal photocoagulation in normotensive eyes with proliferative diabetic retinopathy.

    Bozic, Marija M; Karadzic, Jelena B; Kovacevic, Igor M; Marjanovic, Ivan S

    2017-06-26

    To assess the effect of panretinal laser photocoagulation on ocular pulse amplitude (OPA) in normotensive eyes with proliferative diabetic retinopathy. Prospectively, we performed unilateral argon laser panretinal photocoagulation (PRP) in 30 patients with diabetes mellitus type II and previously untreated bilateral proliferative diabetic retinopathy. Before and 7 and 30 days after the treatment, OPA was measured using dynamic contour tonometer. Compared with the untreated contralateral eyes, laser photocoagulation led to a reduction of OPA. Ocular pulse amplitude did not significantly differ in photocoagulated eyes 7 days after the treatment, but there was a significant difference in OPA 30 days after the treatment. The decrease in OPA values was 15% 7 days after PRP and 40% 30 days after PRP. Ocular pulse amplitude reduction after PRP indirectly informs us about choriocapillary closure, already reported in previous studies.

  11. Transscleral diode photocoagulation of large retinal and choroidal vascular lesions.

    Yun Feng

    Full Text Available BACKGROUND: Transscleral retinal photocoagulation with a diode laser is used in glaucoma refractory to medical and surgical treatment. Our main research question was how the technique performed in large vascular lesions associated with hemangiomas of the retina and choroid. METHODOLOGY/CLINICAL FINDINGS: Patient charts were retrieved from the hospital files for patients who underwent the procedure and were followed for at least 24 months. Five patients (6 eyes fit the criteria. Cases included Von Hippel's disease (2 eyes, Coats' disease (1 eye and choroidal hemangioma (3 cases. Transscleral diode laser treatment was performed under retrobulbar and topical anesthesia with a retinopexy probe (IRIS DioPexy, IRIS Medical Instruments, Mountain View, CA applied transsclerally under indirect ophthalmoscope visualization. We found an improvement in best-corrected visual acuity at 24 months postoperatively. CONCLUSIONS/SIGNIFICANCE: Transscleral photocoagulation may have a clinical application in these diseases as an alternate to the high cost of photodynamic therapy with photosensitizing agents.

  12. Cyclo-photocoagulation in the management of aphakic glaucoma

    Lee, P.-F.

    1984-01-01

    Transpupillary argon laser photocoagulation of the ciliary processes (TALC) through a widely dilated pupil, with or without cerebral depression, has been used in the management of glaucoma in aphakic eyes for a number of years. 58% of glaucoma in aphakics treated with TALC showed sustained and meaningful intraocular pressure reduction 2 months to 5 years after the procedure. Clinically, the TALC procedure is a relatively safe, effective, and an useful alternative approach in the management of selected cases of glaucoma in aphakics. (Auth.)

  13. 虹膜切口氪激光预光凝在青光眼激光治疗中的临床研究%Clinical Research of Pre-photocoagulation of Iris Cut by Krypton Laser in Glaucoma Laser Treatment

    张磊

    2011-01-01

    Objective To observe the effect of pre - photocoagulation iris by krypton laser in glaucoma laser treatment. Methods All 78 cases( 92 eyes )were grouped into A and B. Group A was treated by krypton laser peripheral iridoplasty( LPIP ), iris pre - photocoagulation and YAG laser peripheral iridectomy ( LPI ). Group B was only treated by LPIP and YAG LPI. After laser Treatment, IOP, visual acuity and iris haemorrhage were observed. Results The difference of IOP and iris haemorrhage between group A and group B was statistically significant( P < 0.05 ). Conclusion The method of pre - thermocoagulation iris by krypton laser can reduce the complication of glaucoma laser treatment effectively.%目的 观察虹膜切口氪激光预光凝对青光眼激光治疗的影响.方法 将我院门诊需行激光治疗的青光眼患者78例(92只眼)随机分成A、B组.A组行虹膜氪激光周边成形+切口周围预光凝+YAG激光切开术.B组行虹膜氪激光周边成形+YAG激光切开术,治疗后观察两组的视力、眼压、虹膜出血等指标.结果 比较两组在治疗后眼压和虹膜出血等并发症情况的差异有统计学意义(P < 0.05).结论 氪激光虹膜切口预光凝可以有效地降低青光眼激光治疗后的并发症.

  14. A Novel Nanoparticle Mediated Selective Inner Retinal Photocoagulation for Diseases of the Inner Retina.

    Singh, Rupesh; Rajaraman, Srinivas; Balasubramanian, Madhusudhanan

    2017-10-01

    A novel nanoparticle mediated methodology for laser photocoagulation of the inner retina to achieve tissue selective treatment is presented. Transport of 527, 577, and 810 nm laser, heat deposition, and eventual thermal damage in vitreous, retina, RPE, choroid, and sclera were modeled using Bouguer-Beer-Lambert law of absorption and solved numerically using the finite volume method. Nanoparticles were designed using Mie theory of scattering. Performance of the new photocoagulation strategy using gold nanospheres and gold-silica nanoshells was compared with that of conventional methods without nanoparticles. For experimental validation, vitreous cavity of ex vivo porcine eyes was infused with gold nanospheres. After ~6 h of nanoparticle diffusion, the porcine retina was irradiated with a green laser and imaged simultaneously using a spectral domain optical coherence tomography (Spectralis SD-OCT, Heidelberg Engineering). Our computational model predicted a significant spatial shift in the peak temperature from RPE to the inner retinal region when infused with nanoparticles. Arrhenius thermal damage in the mid-retinal location was achieved in ~14 ms for 527 nm laser thereby reducing the irradiation duration by ~30 ms compared with the treatment without nanoparticles. In ex vivo porcine eyes infused with gold nanospheres, SD-OCT retinal images revealed a lower thermal damage and expansion at RPE due to laser photocoagulation. Nanoparticle infused laser photocoagulation strategy provided a selective inner retinal thermal damage with significant decrease in laser power and laser exposure time. The proposed treatment strategy shows possibilities for an efficient and highly selective inner retinal laser treatment.

  15. 氪离子激光光凝治疗糖尿病视网膜病变疗效观察%Clinical research in the treatment of diabetic retinopathy with krypton lasers photocoagulation

    李翠英

    2013-01-01

    目的 观察氪离子激光治疗糖尿病视网膜病变(DR)的效果.方法 荧光素眼底血管造影(FFA)确诊为Ⅲ~Ⅴ期DR96例(184只眼),术前查视力、裂隙灯、眼底和FFA,根据病变部位、性质、屈光介质情况选择不同波长激光进行全视网膜光凝(PRP),术后随访6~36个月.结果 治疗后184只眼视力提高60只眼,占32.61%;视力无变化90只眼,占48.91%;视力下降34只眼,占18.48%.结论 氪离子激光治疗可提高或保护DR患者的视功能.%Objective To observe the effects of krypton lasers on diabetic retinopathy. Methods 96 cases (184 eyes) of diabetic retinopathy in the stages of Ⅲ - Ⅴ were reviewed and identified by fundus fluorescein angiography (FFA). The visual acuity, slit-lamp, ophthalmoscopy and fundus fluorescein angiography were performed preoperatively. They were treated with krypton lasers paneretinal photocoagulation, according to the characteristics and the different manifestations of the affected eyes. The follow-up period was 6-36 months. Results Visual acuity improved in 60 eyes (32.61% ), remained with no changes in 90 eyes (48.91% ), and decreased in 34 eyes (18.48% ). Conclusion The krypton lasers is a safe and effective approach in treating diabetic retinopathy. It can improve or retain patients vision.

  16. Successful Surgical Management of Retinopathy of Prematurity Showing Rapid Progression despite Extensive Retinal Photocoagulation.

    Gadkari, Salil S; Kulkarni, Sucheta R; Kamdar, Rushita R; Deshpande, Madan

    2015-01-01

    The management of retinopathy of prematurity (ROP) can be challenging in preterm babies with a gestational age premature infant presented with "hybrid" zone 1 disease in the right eye and aggressive posterior ROP in the left eye. Both eyes were adequately treated with laser photocoagulation; however, the eyes deteriorated and progressed to stage 4 ROP. Both eyes eventually underwent intravitreal bevacizumab followed by lens sparing vitrectomy with good anatomical and visual outcome. Anticipation of progression despite laser photocoagulation in certain clinical scenarios, frequent follow-up and timely surgical intervention is paramount.

  17. The application about krypton laser photocoagulation and intravitreal C3F8 in retinal detachment after vitrectomy%氪激光联合玻璃体腔C3F8填充在玻璃体切除术后视网膜脱离中的应用

    李红; 蒋模; 蔡善君

    2013-01-01

    目的 探讨氪激光视网膜光凝联合玻璃体腔注气术在玻璃体切除、眼内气体填充术后发生视网膜脱离中的适应症及临床疗效.方法 对30例因视网膜脱离或玻璃体积血行玻璃体切割、眼内光凝、联合SF6或C3F8填充,术后发现局限性视网膜再脱离的患者采用双针法行玻璃体注气联合视网膜氪激光光凝筑堤的办法,以闭合裂孔,复位视网膜脱离.术中采取双针法交换玻璃体腔部分房水,术后俯卧位休息12~18 h后予全视网膜镜下寻找裂孔,并激光光凝裂孔周围视网膜,激光参数为:能量180~300 mw,曝光时间0.2 s,光斑直径200~300 μm.结果 30眼中,玻璃体腔注C3F8气体联合氪绿激光光凝术后25只眼视网膜脱离复位,随诊3~18月视网膜稳定;4只眼视网膜未能复位,再次行玻璃体腔灌注,视网膜激光光凝及硅油填充,随访6月视网膜脱离复位,术后1只眼未能随访.结论 对于玻璃体切割术后的发生视网膜脱离患者,行氪绿激光光凝联合玻璃体腔注长效气体术是一种操作简单、节省治疗时间和费用较为理想的治疗方法.%OBJECTIVE To investigate the effect about krypton laser photocoagulation with long-gas injection in eyes in the recurrent retinal detachment after vitrectomy and long-acting gas injection. METHODS For 30 cases with retinal detachment and vitreous hemorrhage, carried out vitrectomy surgery combined with SF6 or C3F8 filled, postoperatively found that limitations of retinal detachment in patients used double needle vitreous gas injection combined with retinal krypton laser photocoagulation embankment approach to close the hole and reattach retinal detachment. Took double needle to exchange aqueous Humour, postoperative prone position rest for 12 to 18 hours, then located holes and used laser photocoagulation around them, laser parameters; energy 180-300mw, exposure time 0.2S, spot diameter 200-300μ,m. RESULTS In 30 eyes

  18. Panretinal photocoagulation versus intravitreal injection retreatment pain in high-risk proliferative diabetic retinopathy

    Célia Regina Farias de Araújo Lucena

    2013-02-01

    Full Text Available PURPOSE: To compare pain related to intravitreal injection and panretinal photocoagulation in the management of patients with high-risk proliferative diabetic retinopathy. METHODS: Prospective study including patients with high-risk proliferative diabetic retinopathy and no prior laser treatment randomly assigned to receive panretinal photocoagulation (PRP group or panretinal photocoagulation plus intravitreal ranibizumab (PRPplus group. In all patients, panretinal photocoagulation was administered in two sessions (weeks 0 and 2, and intravitreal ranibizumab was administered at the end of the first laser session in the PRPplus group. Retreatment was performed at weeks 16 and 32 if active new vessels were detected at fluorescein angiography. Patients in the PRPplus group received intravitreal ranibizumab and patients in the PRP group received 500-µm additional spots per quadrant of active new vessels. After the end of retreatment, a 100-degree Visual Analog Scale was used for pain score estimation. The patient was asked about the intensity of pain during the whole procedure (retinal photocoagulation session or intravitreal ranibizumab injection. Statistics for pain score comparison were performed using a non-parametric test (Wilcoxon rank sums. RESULTS: Seventeen patients from PRPplus and 14 from PRP group were evaluated for pain scores. There were no significant differences between both groups regarding gender, glycosylated hemoglobin and disease duration. Mean intravitreal injection pain (±SEM was 4.7 ± 2.1 and was significantly lower (p<0.0001 than mean panretinal photocoagulation pain (60.8 ± 7.8. Twelve out of 17 patients from the PRPplus group referred intensity pain score of zero, while the minimal score found in PRP group was found in one patient with 10.5. CONCLUSION: In patients with high-risk proliferative diabetic retinopathy who needed retreatment for persistent new vessels, there was more comfort for the patient when retreatment

  19. to-twin transfusion after fetoscopic laser surgery

    Intensive Care Unit. Placenta injection with color dye was performed after delivery, and no residual anastomoses were detected. On day 3 of life, increasing abdominal distension and free air on abdominal radiography ... The postoperative course was complicated by stoma retraction requiring revision. The patient had an ...

  20. Analgesic Effects of Tramadol During Panretinal Photocoagulation

    Ko, Byoung-Woo; Shim, Jae-Hang; Lee, Byung-Ro

    2009-01-01

    Purpose To evaluate the effectiveness of tramadol for the reduction of pain in panretinal photocoagulation (PRP). Methods A double-masked randomized controlled study was performed. Fifty-eight eyes in 29 patients with proliferative diabetic retinopathy were enrolled. The eyes of the patients were randomized into two groups. Group A received an empty capsule. Group B received an oral intake of 100 mg tramadol. The capsule used in Group A had the same appearance as that used in Group B. Pain during PRP was assessed using a visual analog scale. Vital signs, including blood pressure and heart rate, were measured. Results The mean pain scores for groups A and B were 4.80±2.10 and 3.83±1.82 (p=0.09). There were no significant differences in the mean pain scores between the two groups. More patients in group A complained of greater pain than moderate intensity (visual analogue scale=4). Systemic blood pressure increased significantly in group A after laser treatment. However, there were no significant differences in the diastolic blood pressure changes between the two groups. We found no statistical correlation in the heart rate changes. Conclusions We failed to prove that tramadol is effective for pain relief because of the small sample size. However, tramadol was effective for the relief of more severe pain. It was also found to stabilize vital sign changes, such as systolic blood pressure during PRP. PMID:20046687

  1. Realtime temperature determination during retinal photocoagulation on patients

    Brinkmann, Ralf; Koinzer, Stefan; Schlott, Kerstin; Ptaszynski, Lars; Bever, Marco; Baade, Alex; Miura, Yoko; Birngruber, Reginald; Roider, Johann

    2011-03-01

    Retinal photocoagulation is a long time established treatment for a variety of retinal diseases, most commonly applied for diabetic macular edema and diabetic retinopathy. The damage extent of the induced thermal coagulations depend on the temperature increase and the time of irradiation. So far, the induced temperature rise is unknown due to intraocular variations in light transmission and scattering and RPE/choroidal pigmentation, which can vary inter- and intraindividually by more than a factor of four. Thus in clinical practice, often stronger and deeper coagulations are applied than therapeutically needed, which lead to extended retinal damage and strong pain perception. The final goal of this project focuses on a dosimetry control, which automatically generates a desired temperature profile and thus coagulation strength for every individual coagulation spot, ideally unburden the ophthalmologist from any laser settings. In this paper we present the first realtime temperature measurements achieved on patients during retinal photocoagulation by means of an optoacoustic method, making use of the temperature dependence of the thermal expansion coefficient of retinal tissue. Therefore, nanosecond probe laser pulses are repetitively and simultaneously applied with the treatment radiation in order to excite acoustic waves, which are detected at the cornea with an ultrasonic transducer embedded in the contact lens and then are processed by PC.

  2. Fetoscopic tracheal occlusion for severe congenital diaphragmatic hernia: retrospective study

    Angélica de Fátima de Assunção Braga

    Full Text Available Abstract Background and objectives: The temporary fetal tracheal occlusion performed by fetoscopy accelerates lung development and reduces neonatal mortality. The aim of this paper is to present an anesthetic experience in pregnant women, whose fetuses have diaphragmatic hernia, undergoing fetoscopic tracheal occlusion (FETO. Method: Retrospective, descriptive study, approved by the Institutional Ethics Committee. Data were obtained from medical and anesthetic records. Results: FETO was performed in 28 pregnant women. Demographic characteristics: age 29.8 ± 6.5; weight 68.64 ± 12.26; ASA I and II. Obstetric: IG 26.1 ± 1.10 weeks (in FETO; 32.86 ± 1.58 (reversal of occlusion; 34.96 ± 2.78 (delivery. Delivery: cesarean section, vaginal delivery. Fetal data: Weight (g in the occlusion and delivery times, respectively (1045.82 ± 222.2 and 2294 ± 553; RPC in FETO and reversal of occlusion: 0.7 ± 0.15 and 1.32 ± 0.34, respectively. Preoperative maternal anesthesia included ranitidine and metoclopramide, nifedipine (VO and indomethacin (rectal. Preanesthetic medication with midazolam IV. Anesthetic techniques: combination of 0.5% hyperbaric bupivacaine (5-10 mg and sufentanil; continuous epidural predominantly with 0.5% bupivacaine associated with sufentanil, fentanyl, or morphine; general. In 8 cases, there was need to complement via catheter, with 5 submitted to PC and 3 to BC. Thirteen patients required intraoperative sedation; ephedrine was used in 15 patients. Fetal anesthesia: fentanyl 10-20 mg.kg-1 and pancuronium 0.1-0.2 mg.kg-1 (IM. Neonatal survival rate was 60.7%. Conclusion: FETO is a minimally invasive technique for severe congenital diaphragmatic hernia repair. Combined blockade associated with sedation and fetal anesthesia proved safe and effective for tracheal occlusion.

  3. Fetal blood gas values during fetoscopic myelomeningocele repair performed under carbon dioxide insufflation.

    Baschat, Ahmet A; Ahn, Edward S; Murphy, Jamie; Miller, Jena L

    2018-05-10

    Fetoscopic myelomeningocele (MMC) repair is performed with intrauterine carbon dioxide (CO 2 ) insufflation. While lamb experiments have shown significant fetal acidemia following CO 2 insufflation corresponding information for human pregnancies is not available. We performed umbilical venous cord blood sampling in three patients during fetoscopic MMC repair at 25+1, 25+3 and 24+1 weeks gestation. Fetal venous pH at the beginning of CO 2 insufflation were 7.36, 7.46 and 7.37; repeat values were 7.28, 7.35, 7.36 after 181, 159 and 149 minutes respectively. The partial pressure of oxygen and carbon dioxide was maintained in the normal range at these times and pH decrease was less in patient 3 receiving humidified CO2 insufflation. Our observations suggest that in contrast to sheep experiments, CO2 insufflation during fetoscopic myelomeningocele repair does not cause fetal acidemia. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. Analgesic Effects of Tramadol During Panretinal Photocoagulation

    Ko, Byoung-Woo; Shim, Jae-Hang; Lee, Byung-Ro; Cho, Hee-Yoon

    2009-01-01

    Purpose To evaluate the effectiveness of tramadol for the reduction of pain in panretinal photocoagulation (PRP). Methods A double-masked randomized controlled study was performed. Fifty-eight eyes in 29 patients with proliferative diabetic retinopathy were enrolled. The eyes of the patients were randomized into two groups. Group A received an empty capsule. Group B received an oral intake of 100 mg tramadol. The capsule used in Group A had the same appearance as that used in Group B. Pain du...

  5. Management of Labor and Delivery After Fetoscopic Repair of an Open Neural Tube Defect.

    Kohn, Jaden R; Rao, Vibha; Sellner, Allison A; Sharhan, Dina; Espinoza, Jimmy; Shamshirsaz, Alireza A; Whitehead, William E; Belfort, Michael A; Sanz Cortes, Magdalena

    2018-06-01

    To report labor, delivery, and neonatal outcomes in a cohort of women delivering neonates who had undergone fetoscopic neural tube defect repair. We conducted a retrospective cohort study from April 2014 to January 2018. All patients met Management of Myelomeningocele Study eligibility criteria. We included patients with completed second-trimester fetoscopic neural tube defect repair (laparotomy, uterine exteriorization, and minimally invasive access through two or three uterine ports) followed by standardized management of labor and delivery at our institution. Outcomes included rates of vaginal delivery, term delivery, and intrapartum cesarean delivery as well as obstetric and neonatal outcomes after oxytocin. Complications of interest included preterm prelabor rupture of membranes, chorioamnionitis, uterine dehiscence or rupture, 5-minute Apgar score less than 7, and neonatal acidosis (umbilical artery pH less than 7.15). Thirty-four patients had fetoscopic repair, followed by 17 vaginal deliveries (50%, 95% CI 32-68%). Median gestational age was 38 1/7 weeks at vaginal delivery (range 26 0/7-40 2/7 weeks of gestation) and 37 1/7 weeks of gestation at cesarean delivery (range 25 5/7-40 5/7 weeks of gestation); 62% of deliveries occurred at term. Eight patients had prelabor cesarean delivery: three nonurgent and five urgent (for nonreassuring fetal heart tracings). Twenty-six patients labored; six were induced and 20 labored spontaneously. Of the latter, five were augmented. Of 26 laboring patients, 17 delivered vaginally and nine underwent urgent cesarean delivery (35%, 95% CI 17-56%; seven nonreassuring fetal heart tracings and two breech). There were no cases of uterine rupture or dehiscence. Most (94%, 95% CI 80-99%) had normal 5-minute Apgar scores; one neonate (3%, 95% CI 0-15%) had acidosis but normal Apgar scores. Our data regarding trial of labor, use of low-dose oxytocin, and vaginal delivery after prenatal fetoscopic neural tube defect repair are

  6. In vitro Models of Laser Induced Injury: Pathophysiology and Cytoprotection

    Bowman, Phillip D; Schuschereba, Steven T

    2007-01-01

    Lasers generating predominantly thermal energy are used in medicine and research for a variety of purposes including surgical excision, pan retinal photocoagulation for treating diabetic retinopathy...

  7. Real time speckle monitoring to control retinal photocoagulation

    Bliedtner, Katharina; Seifert, Eric; Brinkmann, Ralf

    2017-07-01

    Photocoagulation is a treatment modality for several retinal diseases. Intra- and inter-individual variations of the retinal absorption as well as ocular transmission and light scattering makes it impossible to achieve a uniform effective exposure with one set of laser parameters. To guarantee a uniform damage throughout the therapy a real-time control is highly requested. Here, an approach to realize a real-time optical feedback using dynamic speckle analysis in-vivo is presented. A 532 nm continuous wave Nd:YAG laser is used for coagulation. During coagulation, speckle dynamics are monitored by a coherent object illumination using a 633 nm diode laser and analyzed by a CMOS camera with a frame rate up to 1 kHz. An algorithm is presented that can discriminate between different categories of retinal pigment epithelial damage ex-vivo in enucleated porcine eyes and that seems to be robust to noise in-vivo. Tissue changes in rabbits during retinal coagulation could be observed for different lesion strengths. This algorithm can run on a FPGA and is able to calculate a feedback value which is correlated to the thermal and coagulation induced tissue motion and thus the achieved damage.

  8. 0.1%双氯芬酸钠眼液对减轻视网膜光凝疼痛程度的观察%Analgesic effect of sodium diclofenac 0.1% drops on retinal laser photocoagulation

    高建伟; 张阿芳

    2015-01-01

    Objective To evaluate the analgesic effect of sodium diclofenac 0.1% on retinal laser photocoagulation.Methods Among the 86 patients,45 patients with proliferative diabetic retinopathy were treated by two sessions of panretinal photocoagulation (group A),and 41 patients with nonproliferative diabetic retinopathy underwent grid treatment of the posterior pole (19 bilaterally) (group B).Sodium diclofenac 0.1% or sodium chloride 0.9% drops were topically applied 30 minutes before laser treatment in a masked fashion.Patients who had two sessions were given the alternate drug in the second one.Pain level was evaluated immediately after laser treatment with the visual analogue scale (VAS).The results were statistically analyzed.Results Patients in group A had pain in 85/90 sessions (94%).The average pain level was 44.2% with sodium diclofenac 0.1% drops and 53.1% with sodium chloride 0.9% drops (P =0.011).Patients in group B had pain in only 16/60 sessions (26.7%),and the pain level ranged from 10% to 60% regardless of the kind of drops used.There was no correlation in either group between level of pain and average energy level used (160-380 mW).Conclusions Sodium diclofenac 0.1% is useful for pain reduction and should be applied before panretinal photocoagulation.%目的 观察0.1%双氯芬酸钠眼液对视网膜光凝过程中疼痛程度的影响.方法 将86例患者分为两组,A组45例患者患增殖性糖尿病视网膜病变,给予每周1次视网膜光凝术,共两次.B组41例患者患非增殖性糖尿病视网膜病变合并黄斑水肿,19例为双眼,22例为单眼,给予黄斑格栅样光凝,0.1%双氯芬酸钠眼液和0.9%氯化钠注射液视网膜光凝前30 rmin点眼.行两次激光光凝患者第1次和第2次随机应用不同药物.应用视觉模拟评分法(visual analogue scale,VAS)对疼痛反应进行评估,数据进行统计学分析.结果 A组患者90次光凝中85次(94%)出现疼痛,其中应用0.1%双

  9. 间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离%Krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles in the treatment of retinal detachment

    郑穗联; 陈如; 王若洁; 蔡剑秋; 施明光

    2011-01-01

    Objective To assess the clinical result of the krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles.Methods Forty-one eyes of 41 patients were treated with encircling scleral buckles and drainage, some combined with intravitreal injection of gas or balanced salt solution (BSS).All of the retinal breaks were treated with krypton laser photocoagulation using indirect ophthalmoscopy after surgery.Results The visual acuity improved (P<0.05).The reattachment of the retina: 36 eyes were successfully repaired, 5 eyes became recurrent retinal detachment (the reattachment rate was 88.37%).Among the 5 cases, 4 patients were successfully treated with vitrectomy except one patient of traumatic retinal detachment was given up.Conclusions The treatment of retinal detachment should follow the principles of simple surgical methods and fewer complications.The krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles in the treatment of retinal detachment in proper cases is a safe, simple and convenient, easy operated and effective method.%目的 讨论采用间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离的临床疗效.方法 对41例41只眼PVRB级或以下的孔源性视网膜脱离病人行宽环扎、放液,部分病人联合玻璃体腔注气或平衡液,术后间接镜氪激光治疗视网膜裂孔.结果 视力提高:术后视力为3.87±0.74,术前视力为3.40±0.86,P<0.05.视网膜复位情况:41只眼中手术成功36只眼,5只眼复发性,成功率88.37%.5只眼复发性视网膜脱离,除1例外伤性视网膜脱离放弃手术外,其余患者均行玻璃体手术后复位.结论 对视网膜脱离术我们建议遵循手术方式简单、并发症少的原则.选择适当病例,间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离是一种安全、简便、易操作、效果良好的方法.

  10. 氪黄激光光凝联合球后注射曲安奈德治疗糖尿病性黄斑水肿%Macular Photocoagulation by Krypton Yellow Laser Combined with Retrobulbar Injection of Triamcinolone Acetonide for Diabetic Macular Edema

    彭志华; 陈中山; 金小琴; 吴岚; 宋艳萍

    2011-01-01

    目的 探讨氪黄激光黄斑格栅光凝联合球后注射曲安奈德(TA)治疗糖尿病性黄斑水肿的方法及疗效.方法 对123例215只眼糖尿病性黄斑水肿患者进行黄斑部氪黄激光格栅光凝联合球后注射TA治疗,同时选择同期采用其他药物治疗的糖尿病性黄斑水肿患者79例144只眼作为对照组.治疗前后行视力、眼压、眼底,以及眼底荧光造影(FFA)和光学相干层析(OCT)检查.随访1年,观察治疗前后患者视力、黄斑水肿和黄斑区视网膜厚度的变化.结果 光凝联合TA组治疗后患者视力提高者112只眼(52.1%),黄斑水肿完全消退者137只眼(63.7%),部分消退者69只眼(32.1%),黄斑区视网膜厚度正常者122 只眼(56.7%);对照组治疗后视力无提高,黄斑水肿无完全消退者,部分消退者2只眼(1.4%),黄斑区视网膜厚度无达正常者.两组比较,差异具有非常显著意义.结论 氪黄激光光凝联合球后注射TA治疗糖尿病性黄斑水肿疗效显著,无明显并发症发生.%Objective To explore the clinic therapeutic methods and effect of macular grid photocoagulation by krypton yellow laser combined with retrobulbar injection of triamcinolone acetonide(TA) for diabetic macular edema, and to investigate the safety of treatment. Methods Totally 123 patients (215 eyes) diagnosed as diabetic macular edema were performed with macular grid photocoagulation by krypton yellow laser combined with retrobulbar injection of TA ( combined group). The control group of 79 patients ( 144 eyes ) was treated with other drugs. The best-corrected visual acuity ( BCVA), examination of the ocular fundus, FFA and OCT were investigated before and after treatment. Results At the final follow-up, in combined group, BCVA improved in 112 eyes (52. 1% ), complete resolution of macular edema in 137 eyes (63.7%), partial resolution in 69 eyes (32. 1% ), and macular retinal thickness became normal in 122 eyes (56. 7% ). In control group, no

  11. Decreased ocular blood flow after photocoagulation therapy in neonatal retinopathy of prematurity.

    Matsumoto, Tadashi; Itokawa, Takashi; Shiba, Tomoaki; Tomita, Masahiko; Hine, Kotaro; Mizukaki, Norio; Yoda, Hitoshi; Hori, Yuichi

    2017-11-01

    To evaluate the relationships between optic nerve head blood flow, expressed as mean blur rate (MBR) measured by laser speckle flowgraphy (LSFG), and photocoagulation therapy in neonates with retinopathy of prematurity (ROP). Case series study. We studied 5 ROP neonates either during sleep or under sedation both before and after photocoagulation, and evaluated 8 eyes in which the circulation could be measured three times consecutively. Correlations between the MBR-A (mean of all values), MBR-V (vessel mean) and MBR-T (tissue mean) and postmenstrual age were evaluated using Spearman's rank correlation coefficient. In addition, correlations between the relative MBR (-A, -V, -T) value and number of photocoagulation burns and the NV score were evaluated. Differences between post-treatment MBR in ROP subjects and normal neonates' MBR were estimated using analysis of covariance (ANCoVA), with adjustment for postmenstrual age. The relative MBR (-A, -V, -T) values after photocoagulation were 69.6 ± 16.0%, 66.7 ± 17.0% and 74.3 ± 14.6%, respectively. Postmenstrual age was significantly correlated with post-treatment MBR-A (r = 0.83, p = 0.0101), MBR-V (r = 0.85, p = 0.007) and MBR-T (r = 0.76, p = 0.0282). The relative MBR-T value was significantly correlated with the number of photocoagulation burns (r = -0.75, p = 0.033) and NV score (r = -0.72, p = 0.0437). The ANCoVA results showed no significant difference between post-treatment MBR and normal neonates' MBR. Photocoagulation improved the dilation of veins and tortuosity of arteries and reduced ocular blood flow in ROP subjects. Since the post-treatment MBR was not different from a normal neonate's MBR, it is suggested that the pre-treatment MBR was higher in severe ROP cases.

  12. Dosimetry for photo-coagulation by the use of autofluorescence

    Brodzinski, T.

    1989-01-01

    A basic problem when using lasers in medicine is that of dosimetry. The definition of the terms dose, effective value etc. will be dealt with in Chapter 2. This chapter is intended to give an insight into the problems of basic dosimetry and its technical realization within the field of photocoagulation, an established method used to treat the retina, or some skin diseases. Until now the coagulation process was assessed to be completed when the irradiated area became blanched. However in terms of dosimetry, it must be possible to predict or at least to monitor the biological effect using well-defined parameters for the laser or in achieving an objective measure for a feedback loop. In the case of coagulation, a prediction in this form is not possible. There are two ways of pro- ceeding further see Fig. 1. One can either determine the physical effect, i.e. temperature, by some kind of sensors, or even better, use some biological effect as a direct measure of the effective dose applied.

  13. Percutaneous fetoscopic closure of large open spina bifida using a bilaminar skin substitute.

    Lapa Pedreira, Denise A; Acacio, Gregório L; Gonçalves, Rodrigo T; Sá, Renato Augusto M; Brandt, Reynaldo A; Chmait, Ramen; Kontopoulos, Eftichia; Quintero, Ruben A

    2018-01-04

    We have previously described our percutaneous fetoscopic technique for the treatment of open spina bifida (OSB). However, approximately 20-30% of OSB defects are too large to allow primary skin closure. We hereby describe a modification of our standard technique using a bilaminar skin substitute to allow closure of such large spinal defects. The aim of this study was to report our clinical experience with the use of a bilaminar skin substitute and a percutaneous fetoscopic technique for the prenatal closure of large spina bifida defects. Surgeries were performed between 24.0 and 28.9 gestational weeks under general anesthesia, using an entirely percutaneous fetoscopic approach with partial CO2 insufflation of the uterine cavity, as previously described. If there was enough skin to be sutured in the midline, only a biocellulose patch was placed over the placode. In cases where skin approximation was not possible, a bilaminar skin substitute (two layers: one silicone and one dermal matrix) was placed over the biocellulose. The surgical site was assessed at birth, and long-term follow-up was performed. Forty-seven consecutive fetuses underwent percutaneous fetoscopic OSB repair. Premature preterm rupture of membranes (PPROM) occurred in 38 (84%), and the mean gestational age at delivery was 32,8 + 2.5 weeks. A bilaminar skin substitute was required in 13 (29%), of which 5 was associated with myeloschisis. In all cases the skin substitute was found at the surgical site, at birth. In 3 (15%) of these cases, postnatal additional repair was needed. In the other 10 cases, the silicone layer detached spontaneously from the dermal matrix (average 25 days after birth), and the lesion healed by secondary-intention. Operating time was significantly longer in cases requiring the bilaminar skin substitute (additional 42 minutes). The subgroup with bilaminar skin substitute had similar PPROM rate and delivery gestational age compared to the one patch group. Complete reversal of

  14. Effect of intravitreal triamcinolone acetonide on healing of retinal photocoagulation lesions.

    Nomoto, Hiroyuki; Lavinsky, Daniel; Paulus, Yannis M; Leung, Loh-Shan; Dalal, Roopa; Blumenkranz, Mark S; Palanker, Daniel

    2013-01-01

    To evaluate the effect of intravitreal triamcinolone acetonide (TA) on healing of retinal photocoagulation lesions using drug and laser dosing typically employed in clinical practice. Laser burns with a 267-μm retinal beam size at 532-nm wavelength were applied to 40 eyes of Dutch belted rabbits. Barely visible to intense lesions were produced with pulses of 5, 10, 20, and 50 milliseconds and power of 175 mW. Eyes received intravitreal injections of either 2 mg TA/50 μL or balanced salt solution administered either 1 week before or immediately after laser treatment. Lesion grades were assessed acutely ophthalmoscopically and by a masked observer histologically at 1, 3, 7, 30, and 60 days. Both TA groups demonstrated significant reduction in retinal thickness throughout follow-up compared with balanced salt solution groups (P salt solution groups contracted much more than in the TA groups, especially the more intense burns, and this difference persisted to 2 months. The healing rate of the barely visible burns was not significantly affected by TA compared with the balanced salt solution control eyes. Triamcinolone acetonide injection previously or concurrently with photocoagulation significantly decreases laser-induced edema but interferes with lesions healing, thereby leaving wider residual scarring, especially persistent in more intense burns.

  15. [Clinical observation on treating diabetic macular edema with intravitreal triamcinolone acetonide and laser].

    Wang, Yongbo; Shi, Anna; Shi, Xun; Liu, Weifeng

    2010-08-01

    To evaluate the effect of intravitreal injection of triamcinolone acetonide(IVTA) combining with retinal laser treating for diabetic macular edema(DME). Twenty five patients(32 eyes) with DME who has microangioma in macula lutea were randomly divided into group A, B,C and D(8 eyes each group). Eyes in group A were treated with laser photocoagulation. Eyes in group B were treated with multiplier-532 laser photocoagulation and transpupillary thermotherapy. Eyes in group C were treated with multiplier-532 laser photocoagulation and intravitreal triamcinolone acetonide. Eyes in group D were treated with multiplier-532 laser, transpupillary thermotherapy plus triamcinolone acetonide injection. Intravitreal injection of 4 mg triamcinolone acetonide was done 1 week after laser photocoagulation in group C and D. The visual acuity, intraocular pressure, macular thickness (foveal thickness) of the eyes in 4 groups were observed before and 1, 3 and 6 months after treatment. The visual acuity, intraocular pressure and foveal thickness of the 4 groups before treatment showed no significant difference(p> ). The visual acuity, intraocular pressure, macular thickness of eyes in group A, B were better than those of group C, D at 1, 3 and 6 months after treatment, and they had significant difference(p0.05). The effect of laser photocoagulation and intravitreal triamcinolone acetonide, laser photocoagulation combining with transpupillary thermotherapy plus triamcinolone acetonide injectionvisual treating for DME was better than laser photocoagulation alone, laser photocoagulation combining with transpupillary thermotherapy.

  16. VISUAL OUTCOME FOLLOWING PANRETINAL PHOTOCOAGULATION IN PROLIFERATIVE DIABETIC RETINOPATHY

    Nellaye Mani Sindhu

    2018-01-01

    Full Text Available BACKGROUND Diabetes mellitus can be called as a noninfectious pandemic and the incidence of diabetic retinopathy is also uncontrollable. This vision-threatening complication can be treated by early diagnosis and effective treatment like panretinal photocoagulation. The aim of the study is to evaluate the effect of panretinal photocoagulation on visual acuity, colour vision, contrast sensitivity and severity of visual field changes. MATERIALS AND METHODS Prospective study of visual outcome following panretinal photocoagulation in patients with proliferative diabetic retinopathy conducted in Retina Clinic, RIO, Trivandrum, during the time period one year from April 2008. Inclusion Criteria- Eyes with proliferative diabetic retinopathy, visual acuity better than or equal to 6/60, a follow up of at least 6 months after panretinal photocoagulation. Exclusion Criteria- Eyes with cataractous changes in the lens, eyes, which would be undergoing or have undergone focal photocoagulation eyes, which undergone barrage or sectoral retinal photocoagulation, patients with colour blindness, eyes with vitreous haemorrhage and macular preretinal haemorrhage, glaucomatous patients with peripheral field loss. RESULTS The mean age of the patients was 52 years. Male patients (30 outnumbered the female patients (23. Mean duration of diabetes was 14.42 years. Though, there is a statistically significant reduction in visual acuity in the first followup, which was improved and stabilised by 6 months. There is a statistically significant reduction in the contrast sensitivity, which was stabilised after 3 months. Only, 9.5% patients had peripheral constrictions of visual field and no significant change in the colour vision. CONCLUSION We recommend panretinal photocoagulation for all patients with proliferative diabetic retinopathy.

  17. The application of laser plasma in ophthalmology

    He Yujiang; Luo Le; Sun Yabing

    2000-01-01

    The production and development of laser plasma are introduced, and the contribution of laser biomedicine and laser plasma technology to ophthalmology is analyzed. The latest three progresses (laser photocoagulation, photo-refractive keratotomy and laser iridectomy) of laser plasma applications in ophthalmology are presented

  18. Adult Coats’ Disease Successfully Managed with the Dexamethasone Intravitreal Implant (Ozurdex® Combined with Retinal Photocoagulation

    Sebastián Martínez-Castillo

    2012-03-01

    Full Text Available Purpose: To report a case of Coats’ disease managed with the dexamethasone intravitreal implant Ozurdex® (Allergan, Inc., Irvine, Calif., USA combined with retinal photocoagulation. Methods: A 46-year-old female with 20/200 visual acuity was diagnosed with Coats’ disease with secondary retinal vasoproliferative tumor. An initial approach was performed with an intravitreal injection of the sustained-release dexamethasone implant Ozurdex. After reattachment of the retina, the telangiectatic vessels were treated with laser photocoagulation. Results: The patient’s visual acuity improved to 20/25 after the intravitreal Ozurdex. No further recurrences of exudation were evident through the 12-month follow-up. Conclusions: Ozurdex may be an effective initial therapeutic approach for Coats’ disease with immediate anatomical response and visual improvement.

  19. A Computational Model of Peripheral Photocoagulation for the Prevention of Progressive Diabetic Capillary Occlusion

    Thomas J. Gast

    2016-01-01

    Full Text Available We developed a computational model of the propagation of retinal ischemia in diabetic retinopathy and analyzed the consequences of various patterns and sizes of burns in peripheral retinal photocoagulation. The model addresses retinal ischemia as a phenomenon of adverse local feedback in which once a capillary is occluded there is an elevated probability of occlusion of adjacent capillaries resulting in enlarging areas of retinal ischemia as is commonly seen clinically. Retinal burns of different sizes and patterns, treated as local oxygen sources, are predicted to have different effects on the propagation of retinal ischemia. The patterns of retinal burns are optimized with regard to minimization of the sum of the photocoagulated retina and computer predicted ischemic retina. Our simulations show that certain patterns of retinal burns are effective at preventing the spatial spread of ischemia by creating oxygenated boundaries across which the ischemia does not propagate. This model makes no statement about current PRP treatment of avascular peripheral retina and notes that the usual spot sizes used in PRP will not prevent ischemic propagation in still vascularized retinal areas. The model seems to show that a properly patterned laser treatment of still vascularized peripheral retina may be able to prevent or at least constrain the propagation of diabetic retinal ischemia in those retinal areas with intact capillaries.

  20. Fetoscopic Open Neural Tube Defect Repair: Development and Refinement of a Two-Port, Carbon Dioxide Insufflation Technique.

    Belfort, Michael A; Whitehead, William E; Shamshirsaz, Alireza A; Bateni, Zhoobin H; Olutoye, Oluyinka O; Olutoye, Olutoyin A; Mann, David G; Espinoza, Jimmy; Williams, Erin; Lee, Timothy C; Keswani, Sundeep G; Ayres, Nancy; Cassady, Christopher I; Mehollin-Ray, Amy R; Sanz Cortes, Magdalena; Carreras, Elena; Peiro, Jose L; Ruano, Rodrigo; Cass, Darrell L

    2017-04-01

    To describe development of a two-port fetoscopic technique for spina bifida repair in the exteriorized, carbon dioxide-filled uterus and report early results of two cohorts of patients: the first 15 treated with an iterative technique and the latter 13 with a standardized technique. This was a retrospective cohort study (2014-2016). All patients met Management of Myelomeningocele Study selection criteria. The intraoperative approach was iterative in the first 15 patients and was then standardized. Obstetric, maternal, fetal, and early neonatal outcomes were compared. Standard parametric and nonparametric tests were used as appropriate. Data for 28 patients (22 endoscopic only, four hybrid, two abandoned) are reported, but only those with a complete fetoscopic repair were analyzed (iterative technique [n=10] compared with standardized technique [n=12]). Maternal demographics and gestational age (median [range]) at fetal surgery (25.4 [22.9-25.9] compared with 24.8 [24-25.6] weeks) were similar, but delivery occurred at 35.9 (26-39) weeks of gestation with the iterative technique compared with 39 (35.9-40) weeks of gestation with the standardized technique (Pmet in 9 of 12 (75%) and 3 of 10 (30%), respectively, and 7 of 12 (58%) compared with 2 of 10 (20%) have been treated for hydrocephalus to date. These latter differences were not statistically significant. Fetoscopic open neural tube defect repair does not appear to increase maternal-fetal complications as compared with repair by hysterotomy, allows for vaginal delivery, and may reduce long-term maternal risks. ClinicalTrials.gov, https://clinicaltrials.gov, NCT02230072.

  1. Green laser photocoagulator for the treatment of diabetic retinopathy

    The output power stability is better than ± 1.5% with a nearly diffraction-limited beam quality. The system includes various safety and operational features like internal ... with controllable intensity, foot switch, patient records, service mode etc.

  2. Rubber band ligation and infrared photocoagulation for the outpatient treatment of hemorrhoidal disease.

    Ricci, Maurício Pichler; Matos, Délcio; Saad, Sarhan Sydney

    2008-01-01

    To compare the results of rubber band ligation and infrared photocoagulation for the treatment of hemorrhoidal disease through the analysis of the incidence of complications after each treatment and respective success rate. Forty-eight patients with first, second or third degree hemorrhoidal disease were randomized to receive treatment with either rubber band ligation (n=23) or infrared photocoagulation (n=25). Each patient was assessed at 1 week and 4 week intervals after treatment. We compared the incidence of complications and efficiency of each treatment modality and Qui-square, Fisher's Exact Test and Student's t Test were used to statistical analysis. Bleeding occured in eight (34,7%) patients treated with rubber band ligation and in four (16,0%) after infrared photocoagulation (p=0,243). Thirteen (52,0%) patients felt pain during infrared photocoagulation and 9 (39,1%) after rubber band ligation (p=0,546). After rubber band ligation, 14 (60,8%) required medication for pain relief. One patient (4,0%) required medication after infrared photocoagulation (prubber band ligator and 1 (4,0%) treated with infrared photocoagulation had symptomatic mucosal ulcers. Perianal dermatitis occured in two (8,0%) patients treated with infrared photocoagulation and one patient (4,3%) was observed to have prolapsed thrombosed piles after rubber band ligation. One month after treatment, 17 of 23 patients treated with rubber band ligation (73,9%) and 18 of 25 patients treated with infrared photocoagulation were asymptomatic. Rubber band ligation treated bleeding and prolapse in 90,0% and 82,4% respectively. Infrared photocoagulation treats bleeding and prolapse in 93,7% and 87,5% respectively. Those differences are not significant. Rubber band ligation causes significantly more pain than infrared photocoagulation during the first week after the procedures and their success rate are not different after four weeks of treatment.

  3. A case of radiation retinopathy treated with panretinal photocoagulation

    Ohde, Hisao; Ayaki, Masahiko; Fujimura, Hiromi; Yokoyama, Noriko

    1993-01-01

    A 29-year-old male developed radiation retinopathy one year and three months after 60 Gy of radiotherapy was delivered by a linear accelerator for a grade III astrocytoma. Fundus examination at the initial visit showed several dot and blot hemorrhages and cotton-wool patches. One month later, mascular edema developed due to increased capillary permeability in the left eye, while proliferative changes and preretinal hemorrhages were noted in the right eye. Since panretinal photocoagulation was effective in treating both eyes, it may be the treatment of choice for radiation retinopathy with extensive avascular areas. (author)

  4. The relation between bevacizumab injection and the formation of subretinal fibrosis in diabetic patients with panretinal photocoagulation.

    Batman, Cosar; Ozdamar, Yasemin

    2010-01-01

    To report the development of subretinal fibrosis after the injection of intravitreal bevacizumab in eyes with proliferative diabetic retinopathy (PDR) refractory to panretinal laser photocoagulation (PRP). Twenty-one eyes of 15 patients treated with PRP and intravitreal injection of bevacizumab were included in this study. The clinical outcomes of 21 eyes having subretinal fibrosis after intravitreal bevacizumab injection were reviewed. There were 9 men and 6 women with a mean age of 51.3 +/- 8.9 years. All eyes had PDR refractory to panretinal photocoagulation and were treated with at least one intravitreal injection of 1.25 mg of bevacizumab (mean number of injections: 1.8). Before injection, there was subretinal fibrosis in 5 eyes and vitreoretinal traction in 19 eyes. After a mean follow-up period of 7 months, the development or progression of subretinal fibrosis was detected in all eyes. Intravitreal injection of bevacizumab may cause formation or progression of subretinal fibrosis in patients with PDR refractory to PRP. Copyright 2010, SLACK Incorporated.

  5. Photocoagulation treatment for clinically significant radiation macular oedema

    Kinyoun, J.L.; Zamber, R.W.; Lawrence, B.S.; Barlow, W.E.; Arnold, A.M. [Washington Univ., Seattle, WA (United States)

    1995-02-01

    Macular oedema is a leading cause of vision loss in patients with radiation retinopathy. In an effort to find an effective treatment for this vision threatening complication, 12 eyes (eight patients) were treated with photocoagulation for clinically significant radiation macular oedema (CSRMO) defined as central macular thickening, exudates threatening the macular centre, or one disc area of thickening in the macula. Median visual acuity improved from 20/100 pre-operatively to 20/90 at the initial post-operative examination (mean follow up 5 months) and to 20/75 at the final post-operative examination (mean follow up 39 months). At the final post-operative examination, visual acuity had improved in eight (67%) eyes and six (50%) eyes had complete resolution of the CSRMO; two (17%) other eyes had improved anatomically in that fewer CSRMO criteria were present. These results suggest that macular photocoagulation is effective in decreasing macular oedema and improving vision in eyes with CSRMO. (author).

  6. Photocoagulation treatment for clinically significant radiation macular oedema

    Kinyoun, J.L.; Zamber, R.W.; Lawrence, B.S.; Barlow, W.E.; Arnold, A.M.

    1995-01-01

    Macular oedema is a leading cause of vision loss in patients with radiation retinopathy. In an effort to find an effective treatment for this vision threatening complication, 12 eyes (eight patients) were treated with photocoagulation for clinically significant radiation macular oedema (CSRMO) defined as central macular thickening, exudates threatening the macular centre, or one disc area of thickening in the macula. Median visual acuity improved from 20/100 pre-operatively to 20/90 at the initial post-operative examination (mean follow up 5 months) and to 20/75 at the final post-operative examination (mean follow up 39 months). At the final post-operative examination, visual acuity had improved in eight (67%) eyes and six (50%) eyes had complete resolution of the CSRMO; two (17%) other eyes had improved anatomically in that fewer CSRMO criteria were present. These results suggest that macular photocoagulation is effective in decreasing macular oedema and improving vision in eyes with CSRMO. (author)

  7. Rubber band ligation and infrared photocoagulation for the outpatient treatment of hemorrhoidal disease

    Ricci,Maurício Pichler; Matos,Délcio; Saad,Sarhan Sydney

    2008-01-01

    PURPOSE: To compare the results of rubber band ligation and infrared photocoagulation for the treatment of hemorrhoidal disease through the analysis of the incidence of complications after each treatment and respective success rate. METHODS: Forty-eight patients with first, second or third degree hemorrhoidal disease were randomized to recieve treatment with either rubber band ligation (n=23) or infrared photocoagulation (n=25). Each patient was assessed at 1 week and 4 week intervals after t...

  8. Long-term associations between serum lipids and panretinal photocoagulation in type 1 diabetes

    Jørgensen, Jesper Skovlund; Mejnert Jørgensen, Trine; Green, Anders

    2013-01-01

    To examine the predictive value of serum lipids on the need for panretinal photocoagulation (PRP) treatment in a long-term follow-up of a cohort of Danish type 1 diabetic patients.......To examine the predictive value of serum lipids on the need for panretinal photocoagulation (PRP) treatment in a long-term follow-up of a cohort of Danish type 1 diabetic patients....

  9. Orange fiber laser for ophthalmology

    Adachi, M.; Kojima, K.; Hayashi, K.

    2007-02-01

    For the light source of photocoagulators for ophthalmology, orange laser is more suitable than green laser because of low scattering loss by the crystalline lens, and low absorption by xanthophylls in the retina. We developed two orange fiber lasers (580 nm and 590 nm) to investigate the effect depending on the difference in the range of orange. The 580nm laser is composed of a 1160 nm fiber laser and a Periodically Polled Lithium Niobate (PPLN) crystal for second harmonic generation. The 1160 nm fiber laser beam is focused into the MgO-doped PPLN crystal whose length is 30 mm with 3-pass configuration. Continuous-wave 1.3 W output power of 580 nm was obtained with 5.8 W input power of 1160nm for the first time. The conversion efficiency was 22%. The band width of the second harmonic was 0.006 nm (FWHM). The 590 nm laser is almost the same as 580 nm laser source. In this case we used a Raman shift fiber to generate 1180 nm, and the output power of 590 nm was 1.4 W. We developed an evaluation model of photocoagulator system using these two laser sources. A 700 mW coagulation output power was obtained with this orange fiber laser photocoagulator system. This is enough power for the eye surgery. We have the prospect of the maintenance-free, long-life system that is completely air-cooled. We are planning to evaluate this photocoagulator system in order to investigate the difference between the two wavelengths at the field test.

  10. A Comparative Study of Retinal Function in Rabbits after Panretinal Selective Retina Therapy versus Conventional Panretinal Photocoagulation

    Young Gun Park

    2015-01-01

    Full Text Available Purpose. This study evaluates functional changes in electroretinographic findings after selective retina therapy (SRT compared to panretinal photocoagulation (PRP in rabbits. Methods. The right eyes of 12 Chinchilla rabbits received 200 laser treatment spots. The right eyes of six rabbits received SRT (SRT group, whereas the other six animals were treated using PRP on the right eye (PRP group. The eyes were investigated using full-field ERG 1 hour and 3 weeks after treatment. Histologic exam to assess the tissue response of lasers was performed on 3 weeks. Results. No significant changes in the mean ROD or CR b-wave amplitudes of the SRT lesions were evident, compared to baseline, 1 h after laser treatment (p=0.372 and 0.278, resp.. In addition, the OPs and 30 Hz flickers of the SRT lesions were not significantly altered (p=0.17 and 0.243, resp.. At 3 weeks, similar results were found. Comparing the two groups, the ROD b-wave amplitude was reduced in the PRP and SRT groups to 60.04±4.2% and 92.32±6.43% of baseline (p<0.001. Histologically, there was no visible photoreceptor alterations on week 3. Conclusions. SRT in rabbit eyes induced less functional loss than PRP in both rod-mediated retinal function and cone-mediated retinal function. In addition, SRT irradiated eyes had no functional loss compared to its control.

  11. An experimental study on choroidal neovascularization induced by Krypton laser in rat model.

    Cui, Jing; Liu, Yuanyuan; Zhang, Jingkai; Yan, Hua

    2014-01-01

    The purpose of this work was to study the efficacy and safety of choroidal neovascularization (CNV) formation induced by Krypton laser in Brown Norway (BN) rats, and observe the trend of the change of CNV after laser photocoagulation. Twenty-five male BN rats were involved in this study. Two eyes of one rat without any laser photocoagulation were randomly selected as the control group, and the other 48 eyes of 24 rats were selected as the experimental group. Eight eyes of four rats were randomly selected to receive the examinations of fundus fluorescein angiography (FFA), histopathology, and transmission electron microscopy 3, 7, 14, 21, 28, and 56 days after laser photocoagulation. After laser photocoagulation, the leakage appeared in burns on day 7 (59%), reached the peak on day 21 (84%), (p0.05). The thickness of CNV increased from day 7 to day 21 (p0.05). The experimental model of CNV can be successfully induced by Krypton laser in rats with a stable, long-lasting, and high success rate. After laser photocoagulation, the leakages appear on day 7, reach the peak on day 21, and remain stable after day 21.

  12. Regression Rates Following the Treatment of Aggressive Posterior Retinopathy of Prematurity with Bevacizumab Versus Laser: 8-Year Retrospective Analysis

    Nicoară, Simona D.; Ştefănuţ, Anne C.; Nascutzy, Constanta; Zaharie, Gabriela C.; Toader, Laura E.; Drugan, Tudor C.

    2016-01-01

    Background Retinopathy is a serious complication related to prematurity and a leading cause of childhood blindness. The aggressive posterior form of retinopathy of prematurity (APROP) has a worse anatomical and functional outcome following laser therapy, as compared with the classic form of the disease. The main outcome measures are the APROP regression rate, structural outcomes, and complications associated with intravitreal bevacizumab (IVB) versus laser photocoagulation in APROP. Material/Methods This is a retrospective case series that includes infants with APROP who received either IVB or laser photocoagulation and had a follow-up of at least 60 weeks (for the laser photocoagulation group) and 80 weeks (for the IVB group). In the first group, laser photocoagulation of the retina was carried out and in the second group, 1 bevacizumab injection was administered intravitreally. The following parameters were analyzed in each group: sex, gestational age, birth weight, postnatal age and postmenstrual age at treatment, APROP regression, sequelae, and complications. Statistical analysis was performed using Microsoft Excel and IBM SPSS (version 23.0). Results The laser photocoagulation group consisted of 6 premature infants (12 eyes) and the IVB group consisted of 17 premature infants (34 eyes). Within the laser photocoagulation group, the evolution was favorable in 9 eyes (75%) and unfavorable in 3 eyes (25%). Within the IVB group, APROP regressed in 29 eyes (85.29%) and failed to regress in 5 eyes (14.71%). These differences are statistically significant, as proved by the McNemar test (P<0.001). Conclusions The IVB group had a statistically significant better outcome compared with the laser photocoagulation group, in APROP in our series. PMID:27062023

  13. Clinical analysis of intravitreal injection of triamcinolone acetonide combined macular grid photocoagulation treatment for macular edema

    Xian-Hua Jing

    2014-10-01

    Full Text Available AIM: To investigate the clinical efficacy and safety of intravitreal injection of triamcinolone combined macular grid photocoagulation treatment for macular edema. METHODS: Totally 150 cases(150 eyeswith macular edema in our hospital from July 2009 to November 2013 were selected, which were randomly divided into study group(75 cases, 75 eyesand control group(75 cases, 75 eyes. The cases in control group were treated with macular grid photocoagulation treatment, those in the study group used triamcinolone acetonide combined macular grid photocoagulation treatment. Best corrected visual acuity(BCVA, parallel optical coherence tomography(OCTand fundus fluorescein angiography(FFAwere detected before treatment, after treatment 7d, 1, 3, and 9mo. RESULTS:After the treatment, patients' vision were significantly improved in two groups(PPPP>0.05. Fovea macular neurosensory retinal thickness in the study group was significantly lower than that in control group(PCONCLUSION: Triamcinolone acetonide combined macular grid photocoagulation treatment is accurate, can effectively improve the visual acuity, reduce macular edema, it is safe and reliable, and suitable for clinical application.

  14. Medical-grade Sterilizable Target for Fluid-immersed Fetoscope Optical Distortion Calibration.

    Nikitichev, Daniil I; Shakir, Dzhoshkun I; Chadebecq, François; Tella, Marcel; Deprest, Jan; Stoyanov, Danail; Ourselin, Sébastien; Vercauteren, Tom

    2017-02-23

    We have developed a calibration target for use with fluid-immersed endoscopes within the context of the GIFT-Surg (Guided Instrumentation for Fetal Therapy and Surgery) project. One of the aims of this project is to engineer novel, real-time image processing methods for intra-operative use in the treatment of congenital birth defects, such as spina bifida and the twin-to-twin transfusion syndrome. The developed target allows for the sterility-preserving optical distortion calibration of endoscopes within a few minutes. Good optical distortion calibration and compensation are important for mitigating undesirable effects like radial distortions, which not only hamper accurate imaging using existing endoscopic technology during fetal surgery, but also make acquired images less suitable for potentially very useful image computing applications, like real-time mosaicing. In this paper proposes a novel fabrication method to create an affordable, sterilizable calibration target suitable for use in a clinical setup. This method involves etching a calibration pattern by laser cutting a sandblasted stainless steel sheet. This target was validated using the camera calibration module provided by OpenCV, a state-of-the-art software library popular in the computer vision community.

  15. Scatter Photocoagulation Does Not Reduce Macular Edema or Treatment Burden in Patients with Retinal Vein Occlusion: The RELATE Trial.

    Campochiaro, Peter A; Hafiz, Gulnar; Mir, Tahreem A; Scott, Adrienne W; Solomon, Sharon; Zimmer-Galler, Ingrid; Sodhi, Akrit; Duh, Elia; Ying, Howard; Wenick, Adam; Shah, Syed Mahmood; Do, Diana V; Nguyen, Quan D; Kherani, Saleema; Sophie, Raafay

    2015-07-01

    To determine whether scatter and grid laser photocoagulation (laser) adds benefit to ranibizumab injections in patients with macular edema from retinal vein occlusion (RVO) and to compare 0.5-mg with 2.0-mg ranibizumab. Randomized, double-masked, controlled clinical trial. Thirty-nine patients with central RVO (CRVO) and 42 with branch RVO (BRVO). Subjects were randomized to 0.5 mg or 2.0 mg ranibizumab every 4 weeks for 24 weeks and re-randomized to pro re nata ranibizumab plus laser or ranibizumab alone. Mean change from baseline best-corrected visual acuity (BCVA) at week 24 for BCVA at weeks 48, 96, and 144 for second randomization. Mean improvement from baseline BCVA at week 24 was 15.5 and 15.8 letters in the 0.5-mg and 2.0-mg CRVO groups, and 12.1 and 14.6 letters in the 0.5-mg and 2.0-mg BRVO groups. For CRVO, but not BRVO, there was significantly greater reduction from baseline mean central subfield thickness (CST) in the 2.0-mg versus 0.5-mg group (396.1 vs. 253.5 μm; P = 0.03). For the second randomization in CRVO patients, there was no significant difference from week 24 BCVA in the ranibizumab plus laser versus the ranibizumab only groups at week 48 (-3.3 vs. 0.0 letters), week 96 (+0.69 vs. -1.6 letters), or week 144 (+0.4 vs. -6.7 letters), and a significant increase from week 24 mean CST at week 48 (+94.7 vs. +15.2 μm; P = 0.05) but not weeks 96 or 144. For BRVO, there was a significant reduction from week 24 mean BCVA in ranibizumab plus laser versus ranibizumab at week 48 (-7.5 vs. +2.8; P 2.0 vs. +4.8; P 2.0-mg versus 0.5-mg ranibizumab injections and no long-term benefit in BCVA, resolution of edema, or number of ranibizumab injections obtained by addition of laser treatment to ranibizumab. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  16. Efficacy of patterned scan laser in treatment of macular edema and retinal neovascularization

    Dimple Modi

    2009-08-01

    Full Text Available Dimple Modi, Paulpoj Chiranand, Levent AkdumanSaint Louis University School of Medicine, Department of Ophthalmology, Saint Louis University Eye Institute, St. Louis, Missouri, USAPurpose: To analyze the benefits, efficacy, and complications of the PASCAL® photocoagulation laser system (OptiMedica, Santa Clara, CA, USA in patients treated at our institution.Methods: We conducted a retrospective chart review of 19 patients (28 eyes who underwent laser treatment using the PASCAL® photocoagulation system from November 2006 to November 2007. These 28 eyes were divided into two groups; group 1 eyes underwent macular grid laser and group 2 eyes underwent panretinal photocoagulation. Treatment was performed for macular edema or for iris or retinal neovascularization. Outcomes measured included best-corrected visual acuity (BCVA, efficacy of laser treatment, complications, duration of the procedure, and pain perception, which were noted in the charts for panretinal treatments.Results: Follow-up was 5.9 ± 2.6 months for group 1 and 5.9 ± 4.0 months for group 2. In group 1, 9/28 eyes required a second treatment for remaining edema. BCVA was stable or better in 66% (14/21 and average central foveal thickness on ocular coherence tomography improved in 71% (15/21. Time to completion for a number of laser patterns for grid photocoagulation was felt to be too long for completing the total pattern safely, although we have not noted any related complications. In group 2, the neovascularization regressed at least partially in 3/7 patients. Patient-reported pain perception was 3.6 on a scale of 1 to 10 for group 2. Occasional hemorrhages occurred secondary to irregular laser uptake at different spots in the patterns. We observed no visual outcome consequences because of these hemorrhages during follow-up.Conclusions: Retinal photocoagulation by the PASCAL® laser has comparable efficacy to historical results with conventional retinal photocoagulation in short

  17. Laser application in tracheobronchial tumors

    Rau, B. Krishna; Krishna, Sharon

    2004-09-01

    Ninety three patients with obstructing tracheobronchial tumors were treated with Neodymium: Yttrium - Aluminum - Garnet (Nd:YAG) laser photocoagulation over a period of six years. There were sixty seven Males and 26 Females with a mean age of 44.3 years (range 6- 79 years). 21 benign and 72 malignant lesions were treated with a total 212 sessions of laser photocoagulation (mean 2.4 sessions). The anatomical distribution of lesions were as follows; larynx 9 (three benign and 6 malignant) trachea 39 (27 benign and 12 malignant) left main bronchus 27 (14 malignant) right main bronchus 24 (14 malignant) and vocal cords - 9 (three malignant). There were 21 patients with squamous cell carcinoma, two adenocarcinomas, one adenoid cystic carcinoma, 7 cases of locally infiltrating tumors from thyroid and esophagus, 6 cases of carcinoid tumor and 16 benign lesions. Twenty one patients had a tracheostomy tube in place when treatment was started. Eighteen of the 21 patients with tracheostomy were weaned off the tube in a mean of 5.5 days from the start of treatment. Lumen was restored in 31 (79.4%) patients. In the other eight (20.6%), lumen was achieved, but not sustained. Complications included bleeding in three cases which were managed conservatively, two cases of pneumothorax, and four cases of bronchospasm. There were six deaths during the follow up but none attributable to the procedure. Laser photocoagulation offered effective treatment in the majority of patients with obstructing tracheobronchial tumors, with acceptable morbidity.

  18. Combined Phacoemulsification, Vitrectomy and Endolaser Photocoagulation in Patients with Diabetic Retinopathy and Cataract

    Wahab, S; Hargun, L. D.

    2014-01-01

    Objective: To determine the outcomes of early vitrectomy and endolaser photocoagulation effects during phacoemulsification in cataractous eyes with diabetic retinopathy. Study Design: Descriptive study. Place and Duration of Study: Ophthalmology Department Unit-II, DUHS, Civil Hospital, Karachi, and Al-Noor Eye Clinic, Karachi, from February 2009 to December 2010. Methodology: Consecutive 54 patients with 7 - 15 years duration of type II diabetes with severe non-proliferative diabetic retinopathy (NPDR) and early proliferative diabetic retinopathy (PDR) who had cataract grade I and II underwent vitrectomy, endolaser photocoagulation and phacoemulsification with IOL implantation. Best corrected visual acuity was main outcomes measure assessed till 6 months follow-up. Results: Out of 54 eyes, 32 patients were females and 22 were males. Majority 47 (87%) eyes gained significant (p < 0.001) improvement of best corrected visual acuity of four lines or better while 5 (9.3%) eyes retained stable visual acuity. In only 2 eyes, vision declined to 3/60 or less. Conclusion: Early vitrectomy with phacoemulsification in severe NPDR and early PDR patients, if assisted or augmented with endolaser photocoagulation, maximizes, early visual rehabilitation with less morbidity and may retard progression of retinopathy. (author)

  19. 绝对期青光眼行睫状体光凝的护理%Absolute phase glaucoma line ciliary body photocoagulation of nursing

    张丽平; 岳蕃

    2013-01-01

    objective Discuss the potential complications of using semiconductor laser photocoagulation treatment period of absolute glaucoma surgery nursing period.methods Of 158 patients with 163 eyes to the potential complications of the semiconductor laser photocoagulation, On preoperative psychological nursing、Ful preoperative preparation;Intraoperative take recumbent position 、Actively cooperate with the operation 、To adjust the laser equipment parameters ,Try to shorten the operation time, Relieve the patient pain; Postoperative pay attention to rest, Reduce activities, To anterior chamber reaction 、Eye pain、High intraocular pressure and suit support treatment. The results 163 eyes in 146 eyes (89.6%) surgery intraocular pressure control stability, To avoid the reoperation even remove eye pain, In addition to 17 cases of intraocular pressure rise again and again, Patients require evisceration line, more than no serious complications.conclusion The potential complications of the semiconductor laser photocoagulation therapy is a simple, safe and effective in the treatment of absolute glaucoma phase method, Reasonable preoperative, intraoperative and postoperative care, can greatly reduce the pain of patients and improve the success rate of laser surgery.%  目的探讨利用半导体激光经巩膜睫状体光凝治疗绝对期青光眼的手术期护理。方法对158例163眼进行半导体激光的经巩膜睫状体光凝,术前进行心理护理、充分术前准备;术中采取卧位、积极配合手术、随时调节激光设备参数,尽量缩短手术时间,减轻患者痛苦;术后注意休息,减少活动,对前房反应、眼部疼痛、高眼压等对症支持处理。结果163眼中146眼(89.6%)手术后眼压控制稳定,避免了再次手术甚至摘除眼球的痛苦,除17例因眼压反复升高,患者要求行眼球摘除,余无严重并发症出现。结论半导体激光经巩膜睫状体光凝治疗是一种

  20. Heparanase-1 activities in the development of laser induced choroidal neovascularization

    Bao-Ke Hou

    2013-04-01

    Full Text Available AIM:To investigate the role of heparanase-1 in laser-induced choroidal neovascularization (CNV.METHODS:Experimental CNV was induced by krypton laser photocoagulation in 15 male Brown Norway rats. Fundus fluorescein angiography and histopathological examination were performed in observing the CNV development. The expression and distribution of heparanase-1 protein in the laser lesions were determined by immunohistochemistry and western blotting analysis.RESULTS:The success rate of laser induced CNV was approximately 75% on 3-4 weeks after laser photocoagulation. The protein levels of heparanase-1 increased significantly in the retina-choroidal complex of CNV models when compared to normal rat eyes (P<0.01. Immunostaining confirmed strong heparanase-1 expressions in all laser lesions, and it displayed to be highest at the newly formed blood vessels within the fibrovascular complex in the subretinal space.CONCLUSION:Heparanase-1 is closely involved in the development of laser induced CNV.

  1. Efficacy of intravitreal ranibizumab injection combined with macular grid photocoagulation for diabetic macular edema

    Hu-Lin Jiang

    2014-07-01

    Full Text Available AIM:To evaluate the clinical efficacy of intravitreal injection of ranibizumab combined with macular grid photocoagulation for diabetic macular edema(DME.METHODS:Totally 60 eyes(60 patientswith DME were randomly divided into 2 groups: 30 eyes of simple injection group underwent intravitreal injection of ranibizumab, and 30 eyes of combined treatment group underwent intravitreal injection of ranibizumab and macular grid photocoagulation 1wk later. The best corrected visual acuity(BCVA, central macular thickness(CMTmeasured by optical coherence tomography(OCTand postoperative complications were observed.RESULTS:In simple injection group, the BCVA after operation were separately 0.390±0.075(4wk, 0.367±0.088(8wkand 0.319±0.064(12wk,the CMT after operation were separately 221.63±112.34μm(4wk, 337.73±99.56μm(8wkand 432.92±100.46μm(12wk, which were much better than pre-operation. But during follow-up, the BCVA presented down trend and the CMT was on the rise slowly. In combined treatment group, the BCVA after operation were separately 0.385±0.036(4wk, 0.382±0.079(8wkand 0.377±0.097(12wk,the CMT after operation were separately 249.77±106.55μm(4wk, 270.40±92.88μm(8wkand 275.84±97.34μm(12wk, which were satisfactory and steady during follow-up, better than simple injection group(PCONCLUSION:Intravitreal injection of ranibizumab can effectively improve visual acuity and decrease central foveal thickness for patients with DME, combining with macular grid photocoagulation can ensure therapeutic effects steady and permanent.

  2. Prophylactic use of the Arabin cervical pessary in fetuses with severe congenital diaphragmatic hernia treated by fetoscopic endoluminal tracheal occlusion (FETO): preliminary experience.

    Dobrescu, Oana; Cannie, Mieke M; Cordier, Anne-Gael; Rodó, Carlota; Fabietti, Isabella; Benachi, Alexandra; Carreras, Elena; Persico, Nicola; Hurtado, Ivan; Gucciardo, Léonardo; Jani, Jacques C

    2016-01-01

    The aim of this study was to describe whether the prophylactic use of a cervical pessary decreases the rate of premature birth in congenital diaphragmatic hernia (CDH) fetuses treated with fetoscopic tracheal occlusion (FETO). The study concerns a consecutive series of cases with CDH and FETO and a group of CDH without FETO. In a subgroup of the FETO group, a prophylactic cervical pessary was inserted the day following the procedure. Gestational age (GA) at birth was the primary outcome. Fifty-nine fetuses with FETO and 47 expectantly managed were included. The last 15 FETO had a cervical pessary inserted. The median GA at delivery in the FETO group with pessary was 35.1 weeks and was not different from that in the FETO group without a pessary (34.3 weeks; p = 0.28) but was below that in the expectantly managed group (38.3 weeks; p cervical pessary does not prolong gestation of CDH fetuses treated with FETO. © 2015 John Wiley & Sons, Ltd. © 2015 John Wiley & Sons, Ltd.

  3. Recent developments in retinal lasers and delivery systems

    Naresh Kumar Yadav

    2014-01-01

    Full Text Available Photocoagulation is the standard of care for several ocular disorders and in particular retinal conditions. Technology has offered us newer lasing mediums, wavelengths and delivery systems. Pattern scan laser in proliferative diabetic retinopathy and diabetic macular edema allows laser treatment that is less time consuming and less painful. Now, it is possible to deliver a subthreshold micropulse laser that is above the threshold of biochemical effect but below the threshold of a visible, destructive lesion thereby preventing collateral damage. The advent of solid-state diode yellow laser allows us to treat closer to the fovea, is more effective for vascular structures and offers a more uniform effect in patients with light or irregular fundus pigmentation. Newer retinal photocoagulation options along with their advantages is discussed in this review.

  4. Laser-Based Strategies to Treat Diabetic Macular Edema: History and New Promising Therapies

    Young Gun Park

    2014-01-01

    Full Text Available Diabetic macular edema (DME is the main cause of visual impairment in diabetic patients. The management of DME is complex and often various treatment approaches are needed. At the present time, despite the enthusiasm for evaluating several new treatments for DME, including the intravitreal pharmacologic therapies (e.g., corticosteroids and anti-VEGF drugs, laser photocoagulation still remains the current standard in DME. The purpose of this review is to update our knowledge on laser photocoagulation for DME and describe the developments in laser systems. And we will also discuss the new laser techniques and review the latest results including benefits of combined therapy. In this paper, we briefly summarize the major laser therapeutics for the treatment of diabetic macular edema and allude to some future promising laser therapies.

  5. Changes in Macular Retinal Layers and Peripapillary Nerve Fiber Layer Thickness after 577-nm Pattern Scanning Laser in Patients with Diabetic Retinopathy.

    Shin, Ji Soo; Lee, Young Hoon

    2017-12-01

    The aim of this study was to evaluate the changes in thickness of each macular retinal layer, the peripapillary retinal nerve fiber layer (RNFL), and central macular thickness (CMT) after 577-nm pattern scanning laser (PASCAL) photocoagulation in patients with diabetic retinopathy. This retrospective study included 33 eyes with diabetic retinopathy that underwent 577-nm PASCAL photocoagulation. Each retinal layer thickness, peripapillary RNFL thickness, and CMT were measured by spectral-domain optical coherence tomography before 577-nm PASCAL photocoagulation, as well as at 1, 6, and 12 months after 577-nm PASCAL photocoagulation. Computerized intraretinal segmentation of optical coherence tomography was performed to identify the thickness of each retinal layer. The average thickness of the RNFL, ganglion cell layer, inner plexiform layer, inner nuclear layer, inner retinal layer, and CMT at each follow-up increased significantly from baseline (p 0.05). Each macular retinal layer and CMT had a tendency to increase for one year after 577-nm PASCAL photocoagulation, whereas the average thickness of retinal pigment epithelium decreased at one-year follow-up compared to the baseline. Although an increase in peripapillary RNFL thickness was observed one month after 577-nm PASCAL photocoagulation, there were no significant changes at the one-year follow-up compared to the baseline. © 2017 The Korean Ophthalmological Society

  6. Effect of ultrasound-guided interstitial laser photocoagulation on benign solitary solid cold thyroid nodules

    Døssing, Helle; Bennedbaek, Finn Noe; Hegedüs, Laszlo

    2006-01-01

    with a cytologically benign solitary solid and scintigraphically cold thyroid nodule causing local discomfort were assigned to one session of ILP (ILP-1) (n = 15) or three monthly ILP sessions (ILP-3) (n = 15) and followed for 6 months. ILP was performed under continuous ultrasound (US)--guidance and with an output...... power of 2.5-3.5 W. Thyroid nodule volume was assessed by US. Pressure and cosmetic complaints were evaluated on a visual analogue scale. MAIN OUTCOME: In the ILP- 1 group, thyroid nodule volume decreased from 10.1 +/- 4.3 mL (mean +/- standard deviation [SD]) to 5.7 +/- 3.2 mL (p = 0...

  7. PHACES syndrome: Diode laser photocoagulation of intraoral hemangiomas in six young patients

    Gianfranco Favia

    2015-01-01

    Conclusions: DLP techniques are an effective and minimally invasive procedure for IH in patients with PHACES, in consideration of the multiple lesions to treat, of the necessity of multiple interventions and the higher compliance of the patients.

  8. Laser assisted soldering: microdroplet accumulation with a microjet device.

    Chan, E K; Lu, Q; Bell, B; Motamedi, M; Frederickson, C; Brown, D T; Kovach, I S; Welch, A J

    1998-01-01

    We investigated the feasibility of a microjet to dispense protein solder for laser assisted soldering. Successive micro solder droplets were deposited on rat dermis and bovine intima specimens. Fixed laser exposure was synchronized with the jetting of each droplet. After photocoagulation, each specimen was cut into two halves at the center of solder coagulum. One half was fixed immediately, while the other half was soaked in phosphate-buffered saline for a designated hydration period before fixation (1 hour, 1, 2, and 7 days). After each hydration period, all tissue specimens were prepared for scanning electron microscopy (SEM). Stable solder coagulum was created by successive photocoagulation of microdroplets even after the soldered tissue exposed to 1 week of hydration. This preliminary study suggested that tissue soldering with successive microdroplets is feasible even with fixed laser parameters without active feedback control.

  9. [Efficacy of topical ketorolac for improving visual function after photocoagulation in diabetic patients with focal macular edema].

    Razo Blanco-Hernández, Dulce Milagros; Lima-Gómez, Virgilio; Asbun-Bojalil, Juan

    2014-01-01

    Photocoagulation reduces the incidence of visual loss in diabetic patients with focal macular edema, but it can induce it for Efficacy of topical ketorolac for improving visual function after photocoagulation in diabetic patients with focal macular edema 6 weeks after treatment and produces visual improvement in some cases. Topical ketorolac may reduce the inflammation caused by photocoagulation and improve visual outcome. To determine the efficacy of topical ketorolac for improving visual function after photocoagulation in diabetic patients with focal macular edema. An experimental, comparative, prospective, longitudinal study in diabetic patients with focal macular edema was conducted. Eyes were randomized into two groups of topical treatment for 3 weeks after photocoagulation (A: ketorolac, B: placebo). Best corrected visual acuity before and after treatment was compared in each group (paired t test), and the proportion of eyes with visual improvement was compared between groups (χ(2)). The evaluation was repeated after stratifying for initial visual acuity (≥ 0.5, < 0.5). There were 105 eyes included. In group A (n= 46) mean visual acuity changed from 0.50 to 0.58 (p= 0.003), and from 0.55 to 0.55 in group B (n= 59, p= 0.83); mean percent change was 22.3% in group A and 3.5% in group B (p= 0.03). Visual improvement was identified in 25 eyes from group A (54.3%) and 19 from group B (32.2%, p= 0.019, RR 1.65); the difference only persisted when initial visual acuity was ≥ 0.5 (10 [40%], group A, 5 [14.7%], group B, p= 0.02, RR 2.72). Topical ketorolac was more effective than placebo to improve best corrected visual acuity in diabetic patients with focal macular edema.

  10. Lasers

    Milonni, Peter W

    1988-01-01

    A comprehensive introduction to the operating principles and applications of lasers. Explains basic principles, including the necessary elements of classical and quantum physics. Provides concise discussions of various laser types including gas, solid state, semiconductor, and free electron lasers, as well as of laser resonators, diffraction, optical coherence, and many applications including holography, phase conjugation, wave mixing, and nonlinear optics. Incorporates many intuitive explanations and practical examples. Discussions are self-contained in a consistent notation and in a style that should appeal to physicists, chemists, optical scientists and engineers.

  11. Changes in retinal venular oxygen saturation predict activity of proliferative diabetic retinopathy 3 months after panretinal photocoagulation.

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin; Peto, Tunde; Grauslund, Jakob

    2018-03-01

    Proliferative diabetic retinopathy (PDR) is a severe blinding condition. We investigated whether retinal metabolism, measured by retinal oximetry, may predict PDR activity after panretinal laser photocoagulation (PRP). We performed a prospective, interventional, clinical study of patients with treatment-naive PDR. Wide-field fluorescein angiography (OPTOS, Optomap) and global and focal retinal oximetry (Oxymap T1) were performed at baseline (BL), and 3 months (3M) after PRP. Angiographic findings were used to divide patients according to progression or non-progression of PDR after PRP. We evaluated differences in global and focal retinal oxygen saturation between patients with and without progression of PDR after PRP treatment. We included 45 eyes of 37 patients (median age and duration of diabetes were 51.6 and 20 years). Eyes with progression of PDR developed a higher retinal venous oxygen saturation than eyes with non-progression at 3M (global: +5.9% (95% CI -1.5 to 12.9), focal: +5.4%, (95% CI -4.1 to 14.8)). Likewise, progression of PDR was associated with a lower arteriovenular (AV) oxygen difference between BL and 3M (global: -6.1%, (95% CI -13.4 to -1.4), focal: -4.5% (95% CI -12.1 to 3.2)). In a multiple logistic regression model, increment in global retinal venular oxygen saturation (OR 1.30 per 1%-point increment, p=0.017) and decrement in AV oxygen saturation difference (OR 0.72 per 1%-point increment, p=0.016) at 3M independently predicted progression of PDR. Development of higher retinal venular and lower AV global oxygen saturation independently predicts progression of PDR despite standard PRP and might be a potential non-invasive marker of angiogenic disease activity. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. Successful treatment of radiation retinopathy with panretinal photocoagulation (PRP) in a patient of orbital MALT lymphoma

    Okamoto, Hiroyuki; Chikuda, Makoto; Kadoya, Kouji

    2012-01-01

    Report a case of satisfactory progress radiation retinopathy after radiation for mucosa-associated lymphoid tissue (MALT) lymphoma. A 26-year-old male patient, referred to our department for lacrimal sac tumor. Biopsy was done by otolaryngology and radiation therapy was performed (total irradiation of 41.4 Gy) as pathological examination revealed MALT lymphoma. Soft exudates and macula edema appeared in posterior pole of the right fundus after radiotherapy. Right vision became 0.5 because of macula edema, and panretinal photocoagulation (PRP) was performed. After PRP, macula edema withdrew and right vision improved to 1.2. It is suggested that the fundus must be monitored after radiation therapy, and early treatment, such as PRP is effective in radiation retinopathy. (author)

  13. Temporal changes in retinal vascular parameters associated with successful panretinal photocoagulation in proliferative diabetic retinopathy

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin

    2018-01-01

    PURPOSE: We aimed to investigate changes in retinal vascular geometry over time after panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PDR). METHODS: Thirty-seven eyes with PDR were included. Wide-field fluorescein angiography (Optomap, Optos PLC., Dunfermline......, Scotland, UK) was used to diagnose PDR at baseline and to assess activity at follow-up month three and six. At each time-point, a trained grader measured retinal vessel geometry on optic disc (OD) centred images using semiautomated software (SIVA, Singapore I Vessel Assessment, National University...... of Singapore, Singapore) according to a standardized protocol. RESULTS: At baseline, the mean age and duration of diabetes were 52.8 and 22.3 years, and 65% were male. Mean HbA1c was 69.9 mmol/mol, and blood pressure was 155/84 mmHg. Of the 37 eyes with PDR, eight (22%) eyes had progression at month three...

  14. Improved photoacoustic dosimetry for retinal laser surgery

    Dufour, Suzie; Brown, Robert B.; Gallant, Pascal; Mermut, Ozzy

    2018-02-01

    Lasers are employed for numerous medical interventions by exploiting ablative, disruptive or thermal effects. In ocular procedures, lasers have been used for decades to treat diseases such as diabetic retinopathy, macular edema and aged related macular degeneration via photocoagulation of retinal tissues. Although laser photocoagulation is well established in today's practice, efforts to improve clinical outcomes by reducing the collateral damage from thermal diffusion is leading to novel treatments using shorter (μs) laser pulses (e.g. selective retinal therapy) which result in physical rather than thermal damage. However, for these new techniques to be widely utilized, a method is required to ensure safe but sufficient dosage has been applied, since no visible effects can be seen by ophthalmoscopy directly post treatment. Photoacoustic feedback presents an attractive solution, as the signal is dependent directly on absorbed dosage. Here, we present a method that takes advantage of temporal pulse formatting technology to minimize variation in absorbed dose in ophthalmic laser treatment and provide intelligent dosimetry feedback based on photoacoustic (PA) response. This method tailors the pulse to match the frequency response of the sample and/or detection chain. Depending on the system, this may include the absorbing particle size, the laser beam diameter, the laser pulse duration, tissue acoustic properties and the acoustic detector frequency response. A significant improvement (<7x) of photoacoustic signal-to-noise ratio over equivalent traditional pulse formats have been achieved, while spectral analysis of the detected signal provides indications of cavitation events and other sample properties.

  15. Evaluation of RNFL thickness and serum cytokine levels after retinal photocoagulation combined with intravitreous Conbercept injection treatment of diabetic retinopathy

    Luo Na

    2016-01-01

    Objective:To evaluate the effect of retinal photocoagulation combined with intravitreous Conbercept injection in RNFL thickness, serum cytokine levels and other aspects of diabetic retinopathy.Methods:A total of 92 patients with diabetic retinopathy (126 eyes) who received inpatient treatment in our hospital from December, 2013 to December 2015 were included in the study and divided into observation group 46 cases (62 eyes) and control group 46 cases (64 eyes) according to random number table, control group received retinal photocoagulation therapy alone, observation group received retinal photocoagulation combined with intravitreous Conbercept injection treatment, and then differences in RNFL thickness, hemodynamic indexes, serum levels of cytokines and others were compared between two groups after treatment.Results: Average RNFL thickness of inner optic disc top, bottom, bitamporal and nasal ring area as well as the average full-cycle 360° RNFL thickness of observation group after treatment was less than those of control group; PSV and EDV values of CRA were higher than those of control group while RI value was lower than that of control group, and PSV, EDV and RI values of CRV were lower than those of control group; serumβ2-GPⅠ, Hcy, VEGF and SDF-1 levels were lower than those of control group while C-peptide and APN levels were higher than those of control group.Conclusion: Retinal photocoagulation combined with intravitreous Conbercept injection can significantly reduce the RNFL thickness of the patients with diabetic retinopathy and optimize the retinal hemodynamic status, and helps to improve patients’ overall conditions.

  16. Changes of levels of plasma ET-1 and NO after intravenous photocoagulation of the varicosis of greater saphenous vein

    Han Li'na; Gu Ying; Liu Fanguang

    2004-01-01

    Objective: To determine the changes of levels of plasma endothelin-1 (ET-1) and nitric oxide (NO) after intravenous photocoagulation of the varicosis of the greater saphenous vein. Methods: Fifty-eight patients with varicosis of greater saphenous vein were treated with intravenous photocoagulation. The levels of plasma ET-1 and NO were determined with radioimmunoassay and Griss method respectively on the 1st, 3rd, 7th and 14th day after the treatment. Another fifty-six patients with varicosis of greater saphenous vein were treated with the traditional high ligation and stripping method. The levels of ET-1 and NO on 1st, 3rd, 7th and 14th day postoperatively were also determined too. Results: The levels of ET-1 and NO, whether inphotocoagulation or traditional treatment group, increased at first, then decreased, approaching normal level finally. The peak levels of ET-1 and NO in photocoagulation group were lower than those in traditional method groups, reaching normal levels earlier. Conclusion: The levels of ET-1 and NO after treatment can reflect the intensity of stress and condition of recovery. (authors)

  17. Residents' training to retinal photocoagulation: virtual reality compared to conventional apprenticeship

    Peugnet, Frederic; Dubois, Patrick; Rouland, Jean-Francois

    1998-06-01

    Virtual reality is one of these recent technologies which can provide an efficient help in the field of surgical apprenticeship. We achieved an original training simulator for retinal photocoagulation destined to the residents of the ophthalmological department. This paper describes the comparison between this new training tool and the conventional practice. Two groups of residents, randomly selected, were trained exclusively by one of these methods. These two groups were under the responsibility of two distinct experts. A final evaluation was made by a third and different expert, ignoring the training mode practiced by each of the residents. The study lasted six months. The results show that this new training mode is at least as efficient as the current one in terms of elapsed time and efficiency. It may even reduce the training duration. These results confirm that a pedagogical simulator could give a new approach in the medical teaching, particularly in its management. Such a device may solve the problems of practitioner's lack of disponibility and of patients' safety and comfort during a conventional training. Furthermore, it could bring an objective way to value the students; practical ability. On the other hand, this preliminary study emphasizes the difficulties in introducing a new modality in a traditional teaching environment.

  18. Effect of diabetic retinopathy and panretinal photocoagulation on retinal nerve fiber layer and optic nerve appearance.

    Lim, Michele C; Tanimoto, Suzana A; Furlani, Bruno A; Lum, Brent; Pinto, Luciano M; Eliason, David; Prata, Tiago S; Brandt, James D; Morse, Lawrence S; Park, Susanna S; Melo, Luiz A S

    2009-07-01

    To determine if panretinal photocoagulation (PRP) alters retinal nerve fiber layer (RNFL) thickness and optic nerve appearance. Patients with diabetes who did and did not undergo PRP and nondiabetic control subjects were enrolled in a prospective study. Participants underwent optical coherence tomography of the peripapillary retina and optic nerve. Stereoscopic optic nerve photographs were graded in a masked fashion. Ninety-four eyes of 48 healthy individuals, 89 eyes of 55 diabetic patients who did not undergo PRP, and 37 eyes of 24 subjects with diabetes who underwent PRP were included in this study. Eyes that had been treated with PRP had thinner peripapillary RNFL compared with the other groups; this was statistically significantly different in the inferior (P = .004) and nasal (P = .003) regions. Optic nerve cupping did not increase with severity of disease classification, but the proportion of optic nerves graded as suspicious for glaucoma or as having nonglaucomatous optic neuropathy did (P = .008). These grading categories were associated with thinner RNFL measurements. Diabetic eyes that have been treated with PRP have thinner RNFL than nondiabetic eyes. Optic nerves in eyes treated with PRP are more likely to be graded as abnormal, but their appearance is not necessarily glaucomatous and may be related to thinning of the RNFL.

  19. Therapeutic application of lasers in ophthalmology

    Misiuk-Hojlo, M.; Krzyzanowska-Berkowska, P.; Hill-Bator, A.

    2007-01-01

    Lasers have found application in diverse branches of medicine. In ophthalmology, laser technology has various therapeutic and diagnostic applications. The purpose of this article is to review the major therapeutic applications of lasers in different eye disorders. The effects of lasers on biological tissues and different laser techniques as well as the indications for laser therapy in various parts of the eye are discussed. Lasers are used to treat glaucoma and many vascular disorders of the retina. Laser treatment may be useful in preventing the development of neovascularization in diabetic retinopathy, BRVO, or CRVO. Laser techniques are also available for the treatment of the exudative form of age-related macular degeneration (AMD) and some malignant and benign intraocular tumors and in retina abnormalities which predispose to rhegmatogenous retinal detachment. Corneal laser surgery is the most frequently applied laser procedure in ophthalmology. PRK, LASIK, and LASEK are used to correct errors in vision such as myopia, hyperopia, and astigmatism. Laser photocoagulation is also helpful in cataract surgery. Nowadays, lasers have become so universal that it is difficult to imagine ophthalmology without them. We are still witnessing rapid advances in the development of laser techniques, especially in plastic surgery, cataract extraction, and ocular imaging. (authors)

  20. [Prognostic factors for laser treatment in retinopathy of prematurity].

    Talu, Simona; Cormos, Diana; Zaharia, Gabriela; Stefanut, Claudia; Popa, Monica; Lucaci, Daiana Ioana

    2011-01-01

    The paper aims to determine the anatomical results of the eyes treated by laser photocoagulation for "threshold" retinopathy of prematurity (ROP) and to identify the potential risk factors for the unfavorable outcomes. A retrospective study including all the consecutive ROPs that were treated by laser photocoagulation between January the 1st 2006 and September the 1st 2009 has been conducted. The followed criteria has been the anatomical result after the laser treatment. The outcomes have been correlated with: the gestational ages, the birth weights, the moment of treatment (postnatal and post-conceptional ages), the sex of the premature infants, the stage and zone of ROR. RESULTS The total number of prematurely newborns that met the screening criteria for ROP in the above-mentioned period has been 474. Of these, 350 (74%) presented no ROP and the remaining 124 (26%) developed various stages of the disease. Within the ROP group, 54 patients required laser therapy (44% of the retinopathies, representing 11% of all the prematures). The anatomical outcome has been favorable in 84% of the treated eyes, the remaining 16% presenting the progression of ROP The results of the treatment depended on the type of ROP, being significantly better in the classic disease as in the agressive posterior disease (APD) (p < 0.05). The gender also influenced the outcome: the results were better in girls as compared with boys (p < 0.05). The precocity of the laser treatment (evaluated by the postnatal and postconceptional age) has positively influenced the ROP evolution (p < 0.05). Laser photocoagulation has proved its efficacy in the treatment of ROP on our cases. The factors that have negatively influenced the postlaser outcome were: the aggressive posterior disease, the delayed moment of the laser therapy and the male gender.

  1. Edaravone is a free radical scavenger that protects against laser-induced choroidal neovascularization in mice and common marmosets.

    Masuda, Tomomi; Shimazawa, Masamitsu; Takata, Shinsuke; Nakamura, Shinsuke; Tsuruma, Kazuhiro; Hara, Hideaki

    2016-05-01

    Choroidal neovascularization (CNV) is a main characteristic in exudative type of age-related macular degeneration (AMD). Our study aimed to evaluate the effects of edaravone, a free radical scavenger on laser-induced CNV. CNV was induced by laser photocoagulation to the subretinal choroidal area of mice and common marmosets. Edaravone was administered either intraperitoneally twice a day for 2 weeks or intravenously just once after laser photocoagulation. The effects of edaravone on laser-induced CNV were evaluated by fundus fluorescein angiography, CNV area measurements, and the expression of 4-hydroxy-2-nonenal (4-HNE) modified proteins, a marker of oxidative stress. Furthermore, the effects of edaravone on the production of H2O2-induced reactive oxygen species (ROS) and vascular endothelial growth factor (VEGF)-induced cell proliferation were evaluated using human retinal pigment epithelium cells (ARPE-19) and human retinal microvascular endothelial cells, respectively. CNV areas in the edaravone-treated group were significantly smaller in mice and common marmosets. The expression of 4-HNE modified proteins was upregulated 3 h after laser photocoagulation, and intravenously administered edaravone decreased it. In in vitro studies, edaravone inhibited H2O2-induced ROS production and VEGF-induced cell proliferation. These findings suggest that edaravone may protect against laser-induced CNV by inhibiting oxidative stress and endothelial cell proliferation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. [Association between visual improvement after photocoagulation and the use of angiotensin converting enzyme inhibitors in diabetic macular oedema].

    Somilleda-Ventura, Selma Alin; García-Rubio, Yatzul Zuhaila; Razo Blanco-Hernández, Dulce Milagros; Lima-Gómez, Virgilio

    2016-01-01

    Angiotensin converting enzyme inhibitors are effective in delaying the progression of diabetic retinopathy. It is unknown if their use is associated with a better visual outcome in patients with diabetic macular oedema. A non-experimental, comparative, longitudinal and retrospective study was performed on patients with diabetic macular oedema treated by focal photocoagulation, and with systemic arterial hypertension treated with angiotensin converting enzyme inhibitors (Group 1), and without hypertension (Group 2). The dependent variable was the proportion with visual improvement, operatively defined as the gain of one or more lines of vision three weeks after photocoagulation. The independent variable was the use of angiotensin converting enzyme inhibitors. The proportion of eyes with visual improvement after treatment was compared between groups using the Chi squared (χ(2)) test. A total of 33 eyes (51.6%) were assigned to group 1, and 31 (48.2%), to group 2. The mean of visual acuity improved after three weeks, compared with baseline (p=0.002). The proportion of eyes with visual improvement did not differ between patients treated with angiotensin converting enzyme inhibitors (45.5%) and those that did not use them (51.6%, p=0.4). There was no statistical difference in the proportion of eyes with visual improvement between patients treated with angiotensin converting enzyme inhibitors and in those where they were not used. There is no support for the inhibition of angiotensin II in addition to photocoagulation for improving the outcome in patients with diabetic macular oedema. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

  3. Argon laser treatment of central serous chorioretinopathy

    Ting- Bing Fang

    2013-04-01

    Full Text Available AIM: To observe the efficacy of the argon laser photocoagulation treatment of central serous chorioretinopathy(CSC. METHODS: The treatment groups: 18 patients(18 eyes, argon laser photocoagulation and oral jolethin, vitamin B1, inosine and venoruton tablets. Control group: 18 patients(18 eyes, oral lecithin complex iodine, vitamin B1, inosine, venoruton tablets. Foveal thickness and neuroepithelial layer detachment range were measured by optical coherence tomography(OCTbefore treatment, after 1 month and 3 months post-operation to compare the decline in value of foveal thickness and neuroepithelial layer detachment range of the two groups. RESULTS: After 1 month of treatment, the decline in value of the center foveal thickness: the value of treatment group was 256±72μm; the value of the control group was 82±57μm, and the difference of the two groups, P <0.05; the decline in value of neuroepithelial layer detachment range: the value of the treatment group was 3 548±168μm, the value of the control group was 1 520±143μm, And the difference of the two groups, P<0.05. After three months of treatment, the decline in value of the center foveal thickness: the value of treatment group was 383±75μm, the value of the control group was 312±67 μm, and the difference of the two groups, P<0.05; decline in value of neuroepithelial layer detachment range: the value of the treatment group was 4 908±172μm, the value of the control group was 4 211±153μm, and the difference of the two groups, P <0.05. The differences were statistically significant between the treatment and the control groups(two independent samples t-test. CONCLUSION:Argon laser photocoagulation treatment of CSC is an effective treatment method and can significantly shorten the course.

  4. Effectiveness of hemorrhoidal treatment by rubber band ligation and infrared photocoagulation.

    Linares Santiago, E; Gómez Parra, M; Mendoza Olivares, F J; Pellicer Bautista, F J; Herrerías Gutiérrez, J M

    2001-04-01

    To demonstrate the effectiveness of the treatment of internal hemorrhoids with rubber band ligation (RBL) and infrared photocoagulation (IRC). From march 1996 to december 1999, we prospectively studied 358 patients with a total of 817 hemorrhoid groups and a follow-up period of 36 months. Distribution according to gender and age was: 210 men with a mean age of 46 years and 148 women with a mean age 45.8 years. The mean number of hemorrhoids treated per patients was 2.3. All of them had complete a follow-up protocol at 15, 30, 60 and 180 days and at 12, 24 and 36 months. Rubber band ligation was performed with McGown ligator and suction pump, placing the band at the base of the hemorrhoid. For the infrared coagulation we used a Lumatec coagulation system, applying at least four shoots around each hemorrhoid, with an exposition time ranging between 1 and 1.5 seconds. Treatment was considered effective when patients became asymptomatic (relief of pain, bleeding or anal itching) and the obliteration of hemorrhoids after the treatment was confirmed by anal inspection and anoscopy. Two hundred ninety five of 358 patients were treated with RBL (82.4%), this treatment being effective in 98% of the patients after 180 days and very good after 36 months. There were 6/295 relapses at 36 months (2%). All minor and major complications were observed within the first 15 days of treatment: rectal tenesmus in 96/295 patients (32.5%), mild anal pain in 115/295 (38.9%), self-limited and mild bleeding after the detachment of the bands in 30/295 (10%), and febricula in one patient. Sixty three of 358 patients were treated with IRC (17.6%). In this group, relapses were observed in 6/63 patients (9.5%) at 36 months, all of them with grade III hemorrhoids that required additional treatment with RBL. All the complications (inherent to the technique) were observed within the first days: mild anal pain in 40/63 patients (63.4%) and mild bleeding in 1/63 (1.6%). The treatment with RBL or IRC

  5. Immediate and long-term changes of fundus autofluorescence in continuous wave laser lesions of the retina.

    Framme, Carsten; Roider, Johann

    2004-01-01

    To determine whether fundus autofluorescence imaging is able to show changes in retinal pigment epithelium (RPE) fluorescence after thermal laser photocoagulation. In vivo imaging of fundus autofluorescence was performed with a scanning laser ophthalmoscope. A laser with a wavelength of 488 nm was used for excitation of the tissue and autofluorescence was detected above 500 nm using a barrier filter. One hundred eight eyes of 87 patients who had had previous laser treatment were monitored. The appearance and size of the laser lesions were documented and correlated to the time of treatment. Immediate changes were observed prospectively in 13 eyes; long-term follow-up was studied retrospectively in 95 eyes. In all patients but one, autofluorescence was decreased in the area of laser lesions 1 hour after laser treatment. After 1 month, previously decreased autofluorescence in all lesions changed to significantly increased autofluorescence, which was stable up to 6 months after treatment. Mixed forms were present approximately 6 to 12 months after treatment, showing a central island of increased autofluorescence surrounded by a ring of decreased autofluorescence. After 1 to 2 years, lesions again changed to complete dark spots, enlarging later on. RPE destruction and subsequent proliferation after continuous wave laser photocoagulation can be visualized noninvasively by autofluorescence imaging. Immediate decreased autofluorescence may indicate acute damage of the RPE, subsequent increased autofluorescence seems to indicate proliferative behavior of the RPE, and final dark spots can indicate RPE atrophy secondary to a denaturation of neurosensory retinal tissue. Thus, autofluorescence can be used in the long-term monitoring of RPE changes after laser treatment. The enlargement of the laser atrophy zone demonstrates the potential risk of visual loss after central laser photocoagulation even years after treatment.

  6. Laser ablation of posterior urethral valves by fetal cystoscopy.

    Martínez, José María; Masoller, Narcis; Devlieger, Roland; Passchyn, Esther; Gómez, Olga; Rodo, Joan; Deprest, Jan A; Gratacós, Eduard

    2015-01-01

    To report the results of fetal cystoscopic laser ablation of posterior urethral valves (PUV) in a consecutive series in two referral centers. Twenty pregnant women with a presumptive isolated PUV were treated with fetal cystoscopy under local anesthesia. Identification and fulguration of the PUV by one or several firing-contacts with diode laser were attempted. Perinatal and long-term outcomes were prospectively recorded. The median gestational age at procedure was 18.1 weeks (range 15.0-25.6), and median operation time was 24 min (range 15-40). Access to the urethra was achieved in 19/20 (95%) cases, and postoperative, normalization of bladder size and amniotic fluid was observed in 16/20 (80%). Overall, there were 9 (45%) terminations of pregnancy and 11 women (55%) delivered a liveborn baby at a mean gestational age of 37.3 (29.1-40.2) weeks. No infants developed pulmonary hypoplasia and all were alive at 15-110 months. Eight (40% of all fetuses, 72.7% of newborns) had normal renal function and 3 (27.3%) had renal failure awaiting renal transplantation. Fetoscopic laser ablation for PUV can achieve bladder decompression and amniotic fluid normalization with a single procedure in selected cases with anyhydramnios. There is still a significant risk of progression to renal failure pre or postnatally. © 2014 S. Karger AG, Basel.

  7. Patient Self-Report of Prior Laser Treatment Reliably Indicates Presence of Severe Diabetic Retinopathy

    GRASSI, MICHAEL A.; MAZZULLA, D. ANTHONY; KNUDTSON, MICHAEL D.; HUANG, WENDY W.; LEE, KRISTINE E.; KLEIN, BARBARA E.; NICOLAE, DAN L.; KLEIN, RONALD

    2009-01-01

    PURPOSE To determine whether patient self-report of prior laser treatment can be used as a reliable tool for assessing the presence of severe diabetic retinopathy. DESIGN This was a retrospective study on two groups of diabetic subjects. METHODS One hundred patients with diabetes were recruited from the general eye and retina clinics at the University of Chicago Hospitals. The patients were asked, “Have you ever received laser treatment for your diabetic eye disease (DED)?” A chart review was then conducted noting if the patient had received either focal laser treatment for diabetic macular edema or panretinal photocoagulation for proliferative diabetic retinopathy. Data from the Wisconsin Epidemiological Study of Diabetic Retinopathy (WESDR) were also analyzed. Participant responses to the question “Have you had laser photocoagulation treatment for your eyes?” were analyzed with documentation of photocoagulation scars determined by grading seven-standard field color fundus photographs. RESULTS In the University of Chicago group, 96 of 100 (96%) of patients were accurate in reporting whether they had received previous laser treatment for DED (sensitivity 95.8%, specificity 96.1%, and positive predictive value 88.5%). In the WESDR analysis, 2,329 of 2,348 (99%) of participants were accurate in reporting whether they had prior laser treatment for DED (sensitivity 96.0%, specificity 99.5%, and positive predictive value 95.6%). CONCLUSIONS The high sensitivity and specificity of our results validate the use of patient self-report as a useful tool in assessing past laser treatment for severe diabetic retinopathy. Patient self-report may be a useful surrogate to clinical examination or medical record review to determine the presence of severe diabetic retinopathy. PMID:19054495

  8. Changes of serum IL-1 and sIL-2R levels after intravenous photo-coagulation in patients with varicose greater saphenous vein

    Han Li'na; Gu Ying; Liu Fanguang

    2004-01-01

    Objective: To determine the changes of serum interleukin 2 (IL-2) and soluble interleukin 2 receptor (sIL-2R) levels in patients with varicose greater saphenous vein after intravenous photocoagulation. Methods: Fifty patients with varicose greater saphenous vein were divided into two groups (mild and severe) according to their clinical symptoms. Serum IL-2 and sIL-2R levels were determined with RIA and ELISA respectively in these patients and 30 controls. Results: Serum levels of IL-2 and sIL-2R in patients of the mild group were about the same as those in the controls. In patients of the severe group, levels of IL-2 decreased and levels of sIL-2R increased significantly. After photocoagulation, the IL-2 levels dropped at first but gradually rose; the reverse was true for the sIL-2R levels. The final levels of IL-2 and sIL-2R approached those before treatment in the mild group. In the severe group, the final IL-2 levels were higher and sIL-2R levels lower than those before photocoagulation. Conclusion: Determination of serum IL-2 and sIL-2R levels revealed information about the immune status of the patients and could be applied for judgement of the treatment effect

  9. Bilateral Simultaneous Rhegmatogenous Retinal Detachment following Laser in situ Keratomileusis

    Erhan Yumusak

    2016-06-01

    Full Text Available A 21-year-old woman developed simultaneous rhegmatogenous retinal detachment after laser in situ keratomileusis (LASIK in both eyes. She underwent pars plana vitrectomy surgery combined with endolaser photocoagulation and silicone oil tamponade in the right eye. A week later, pneumatic retinopexy was done in the left eye. As the retinal tear did not seal, 360° scleral buckling surgery was performed and retina was attached. Bilateral simultaneous rhegmatogenous retinal detachment after LASIK for correction of myopia can be a serious complication. Patients should be informed about the possibility of this complication.

  10. Clinical effect of photocoagulation on retinal thickness in eyes with proliferative diabetic retinopathy%糖尿病视网膜病变视网膜光凝损伤的临床观察

    郝晓璐; 侯豹可; 李莹; 姚毅

    2015-01-01

    Objective To observe the damage and recovecry of panretinal photocoagulation (PRP) by different wavelengths of krypton laser on retina in eyes with proliferative diabetic retinopathy.Methods This was a prospective case-control study of 60 eyes (30 right eyes as krypton green laser group and 30 left eyes as krypton yellow laser group) from 30 patients diagnosed as proliferative diabetic retinopathy.They were treated with panretinal photocoagulation (PRP) by a wavelength of 532 nm of krypton green laser and a wavelength of 561 nm of krypton yellow laser respectively.Baseline and morphological changes of optical coherence tomography (OCT) were evaluated before PRP one hour,one week,two weeks,and four weeks after PRP.The thickness of laser spot on nasal optic area was recorded and compared.The thickness of the laser spot of the same eye at different time points were analyzed by using paired sample t-test,while the thickness of the laser spot of the different eyes at the same time point were analyzed by using independent sample t-test.Results Sixty eyes of 30 patients received krypton green laser and krypton yellow laser for PRP respectively.The retinal thickness before PRP was measured as baseline and compared with that at one hour,one week,two weeks,and four weeks after PRP.OCT showed morphological changes of the same eye after PRP:mean retinal thickness was increased by 8.4% at one hour,and dropped as early as one week by 9.5% while 17.1% at two weeks.It remained stable and unchanging at four weeks compared with the data at two weeks.The difference between different time points was statistically significant.No statistically significant difference was found between different eyes at the same time point.Conclusion Krypton green laser and krypton yellow laser all are effective in treating diabetic retinopathy,and there was no statistically significant difference between them in the effect of pigment epithelium layer of retina.The retinal thickness increased by 10

  11. Fetal Intra-Peritoneal Transfusion for the Management of Very Early Spontaneous Twin Anemia-Polycythemia Sequence in an Obese Patient With a Whole Anterior Placenta.

    Guenot, Cécile; Robyr, Romaine; Jastrow, Nicole; Vial, Yvan; Raio, Luigi; Baud, David

    2016-04-01

    Twin anemia-polycythemia sequence (TAPS) is a rare condition in monochorionic twin pregnancies. Small intertwin placental vascular communications allow transfusion, which results in a hemoglobin difference in the twins in the absence of oligohydramnios or polyhydramnios. We report here a case of TAPS diagnosed at 17 weeks' gestation in an obese patient (BMI 42) with a whole anterior placenta. The only possible treatment at this stage of pregnancy was intra-uterine transfusion (IUT), which was repeated weekly until photocoagulation of placental anastomoses was feasible. Fetoscopic laser surgery is the only curative treatment, but is challenging in TAPS because of the absence of polyhydramnios and the presence of minuscule anastomoses. An anterior placenta and high BMI can make the procedure even more challenging. This case report demonstrates that very early and rapidly progressing TAPS with technically complicated conditions (elevated BMI and anterior placenta) can be successfully managed with IUT until laser procedure is achievable.

  12. Assess the effectiveness of nimesulide in reducing pain in panretinal photocoagulation%尼美舒利在全视网膜光凝术中镇痛效果分析

    程华; 李良平; 程显芹

    2013-01-01

    目的 评估分析尼美舒利在全视网膜光凝术(Panretinal photocoagulation,PRP)中的镇痛效果.方法 应用双盲法进行研究.收集接受PRP治疗的糖尿病视网膜病变患者48例58只眼,随机分为服药组和对照组.在激光治疗前24h开始服用药物2天.激光治疗应用标准化治疗,在治疗结束后应用简式的McGill疼痛问卷表(Short form of the McGill pain questionnaire,SF-MPQ)进行评估,内容包括疼痛分级指数(pain rating index,PRI)、视觉模拟评分(visual analogous scale,VAS)和现有疼痛强度评分(present pain intensity,PPI)3部分,三者的累积分值作为疼痛系数.结果 服药组的PRI为3.8333±2.3057,对照组为4.3333±3.1132,(P>0.05).服药组的VAS为(2.6167±1.1347)分,对照组为(3.2333±0.5942)分,(P<0.05).服药组的PPI为(1.3667±0.6149)分,对照组为(1.1111±0.7511)分,(P>0.05).服药组的疼痛系数为7.8167±3.4046,对照组为8.6778±3.5499,(P>0.05).二者差异无统计学意义.结论 应用尼美舒利超前镇痛法对于缩减PRP疼痛的方法是不明显的.%Objective To evaluate the effectiveness of nimesulide for the reduction of pain in panretinal photocoagulation (PRP).Methods A double-masked randomized controlled study was performed.Fifty-eight eyes in 48 patients undergoing PRP were enrolled and randomised to group nimesulide or placebo,taken for 2 days starting 24 hours before the laser treatment.The laser treatment was performed following a standardized protocol.Pain after treatment was assessed using Short form of the McGill pain questionnaire (SF-MPQ),it included pain rating index (PRI),visual analogous scale (VAS) and present pain intensity (PPI).The score of them was the pain level.Results The PRI for group nimesulide was 3.8333±2.3057 and group placebo was 4.3333±3.1132,(P >0.05).The VAS for group nimesulide was 2.6167±1.1347 and group placebo was 3.2333±0.5942,(P <0.05).The PPI for group nimesulide was 1.3667±0.6149 and group placebo

  13. Efficacy observation on multiple wave length laser for diabetic retinopathy and central retinal vein occlusion

    Tao Tian

    2014-07-01

    Full Text Available AIM:To observe the efficacy of the multiple wave length laser in treating diabetic retinopathy combined with central retinal vein occlusion. METHODS:Totally 95 cases(100 eyeswith diabetic retinopathy combined with central retinal vein occlusion were treated by multiple wave length laser. Krypton yellow laser was used for macular edema in focal photocoagulation and diffuse photocoagulation. For peripheral retina, krypton green or krypton red laser were used. Visual acuity, slit-lamp biomicroscopy, ophthalmoscopy and fundus fluorescein angiography were performed preoperatively and postoperatively. The patients were followed up for 12 to 48wk. In this study, change in visual acuity and macular edema were observed in both groups, and statistical analysis was performed. RESULTS:The effective rate was 61.2% in diffuse macular edema group and 86.3% in focal macular edema group. The general effective rate of later was higher than the former, while the treatment effect had significant statistical difference(PCONCLUSION: Multiple wave length laser is an effective and safe way to treat diabetic macular edema of diabetic retinopathy combined with central retinal vein occlusion,which is worth widely applying in clinical practice.

  14. Fraxel laser indications and long-term follow-up.

    Tanzi, Elizabeth L; Wanitphakdeedecha, Rungsima; Alster, Tina S

    2008-01-01

    Fractional photothermolysis, based on creating spatially precise microscopic thermal wounds, is performed using a 1550-nm erbium fiber laser that targets water-containing tissue to effect the photocoagulation of narrow, sharply defined columns of skin known as microscopic thermal zones. According to the authors, Fraxel resurfacing has been shown to be both safe and effective for facial and nonfacial photodamage, atrophic acne scars, hypopigmented scars, and dyspigmentation. Because only a fraction of the skin is treated during a single session, a series (typically 3 to 6 treatments) of fractional resurfacing at 2- to 4-week intervals is required for the best clinical improvement. It is the authors' experience that a series of Fraxel treatments can achieve a similar clinical result for atrophic scars compared with traditional ablative laser skin resurfacing. However, the improvement seen after a series of Fraxel treatments for perioral laxity and rhytides often falls short of the impressive results that can be achieved with ablative laser skin resurfacing.

  15. Therapeutic application of lasers in ophthalmology; Terapeutyczne zastosowanie laserow w okulistyce

    Misiuk-Hojlo, M; Krzyzanowska-Berkowska, P; Hill-Bator, A [Department of Ophthalmology, Silesian Piasts University of Medicine in Wroclaw (Poland)

    2007-07-01

    Lasers have found application in diverse branches of medicine. In ophthalmology, laser technology has various therapeutic and diagnostic applications. The purpose of this article is to review the major therapeutic applications of lasers in different eye disorders. The effects of lasers on biological tissues and different laser techniques as well as the indications for laser therapy in various parts of the eye are discussed. Lasers are used to treat glaucoma and many vascular disorders of the retina. Laser treatment may be useful in preventing the development of neovascularization in diabetic retinopathy, BRVO, or CRVO. Laser techniques are also available for the treatment of the exudative form of age-related macular degeneration (AMD) and some malignant and benign intraocular tumors and in retina abnormalities which predispose to rhegmatogenous retinal detachment. Corneal laser surgery is the most frequently applied laser procedure in ophthalmology. PRK, LASIK, and LASEK are used to correct errors in vision such as myopia, hyperopia, and astigmatism. Laser photocoagulation is also helpful in cataract surgery. Nowadays, lasers have become so universal that it is difficult to imagine ophthalmology without them. We are still witnessing rapid advances in the development of laser techniques, especially in plastic surgery, cataract extraction, and ocular imaging. (authors)

  16. Krypton laser membranotomy in the treatment of dense premacular hemorrhage.

    Chen, Yung-Jen; Kou, His-Kung

    2004-12-01

    Neodymium:YAG (Nd:YAG) laser and argon laser membranotomy have been used in patients with premacular hemorrhage to drain premacular blood into the vitreous cavity and rapidly clear the hemorrhage. However, the Nd:YAG laser appears to be difficult to use, and argon laser energy may be more likely to be absorbed by the ocular media. We performed a study to evaluate the safety and effectiveness of krypton laser membranotomy in selected cases of premacular hemorrhage. Sixteen patients (17 eyes) with dense premacular hemorrhage for 2 weeks or less were enrolled from April 1998 to February 2004. The causes of premacular hemorrhage were proliferative diabetic retinopathy (PDR) in 12 eyes, Valsalva retinopathy in 3 eyes, leukemia in I eye and retinal arterial macroaneurysm in I eye. Krypton laser was used to create a membranotomy on the sloping edge of the premacular hemorrhage. Five eyes with PDR were treated with inferior panretinal photocoagulation and laser membranotomy simultaneously. After intravitreal dispersion of premacular blood, fundus examination was performed in all eyes and fluorescein angiography in five eyes to evaluate retinal damage. All eyes had visual improvement within 2 weeks postoperatively. No retinal damage was seen at the site of membranotomy in any eye. No eye needed vitrectomy postoperatively during a mean follow-up duration of 18.6 months. Krypton laser membranotomy appears to be a safe and simple alternative procedure for treating selected cases of premacular hemorrhage. Further trials are necessary to evaluate its benefit.

  17. Transscleral diode laser retinopexy in retinal reattachment surgery Retinopexia com laser de diodo transescleral na cirurgia de descolamento de retina

    João Carlos de Miranda Gonçalves

    2004-02-01

    Full Text Available PURPOSE: Transscleral diode retinal photocoagulation (diopexy is becoming an accepted technique in the treatment of selected retinal diseases. The objective of this study is to evaluate diopexy technique in the production of adhesive chorioretinal lesions during the surgical treatment of the rhegmatogenous retinal detachment. METHODS: 25 patients with rhegmatogenous retinal detachment were enrolled in a prospective clinical-surgical study to evaluate the technique of transscleral diode laser photocoagulation to obtain adhesive chorioretinal lesions during retinal reattachment surgery. The surgery consisted of the placement of an exoplant silicon to produce a buckle effect combined with a drainage of subretinal fluid in most cases. RESULTS: By a mean follow-up of 10 months, 21 of 25 eyes had their retinas reattached after only one surgery with diopexy used in all cases. CONCLUSION: Transscleral diode laser photocoagulation was a technically easy, controlled, effective, reproducible and safe means of obtaining chorioretinal adhesion in retinal reattachment surgery.OBJETIVO: Fotocoagulação transescleral com laser de diodo (diopexia está se tornando técnica utilizada no tratamento de algumas doenças retinianas. O objetivo deste estudo é avaliar a técnica de diopexia na produção de lesões coriorretinianas aderentes durante o tratamento cirúrgico do descolamento de retina regmatogênico. MÉTODOS: Vinte e cinco pacientes com descolamento de retina regmatogênico participaram deste estudo clínico-cirúrgico prospectivo para avaliar a técnica de fotocoagulação com laser de diodo transescleral para obter lesões coriorretinianas aderentes durante a cirurgia de descolamento de retina. A cirurgia consistiu de colocação de explante de silicone para produzir efeito de introflexão escleral combinado com drenagem do líquido subretiniano na maioria dos casos. RESULTADOS: Após um período médio de seguimento de 10 meses, em 21 dos 25 olhos

  18. Minimal Invasive Approach for Lips Venous Lake Treatment by 980 nm Diode Laser with Emphasis on the Aesthetic Results. А Clinical Series

    Voynov Parvan P.

    2016-06-01

    Full Text Available Introduction: A venous lake (VL is a vascular lesion with common occurrence in many patients, manifested as a dark blue-to-violet compressible papule, caused by dilation of venules. The main reasons for the treatment of VL are aesthetic. The haemorrhaging episodes or impairment of oral normal functions are also under considerations. Treatment of lip VL includes surgical excision, selective photocoagulation, cryotherapy, sclerotherapy and electrodessication. The high-intensity diode laser is an option. The 980 nm diode laser is selectively absorbed by haemoglobin and selectively destroys blood vessels, minimising injury to the surrounding healthy skin.

  19. Minimal Invasive Approach for Lips Venous Lake Treatment by 980 nm Diode Laser with Emphasis on the Aesthetic Results. А Clinical Series.

    Voynov, Parvan P; Tomov, Georgi T; Mateva, Nonka G

    2016-01-01

    A venous lake (VL) is a vascular lesion with common occurrence in many patients, manifested as a dark blue-to-violet compressible papule, caused by dilation of venules. The main reasons for the treatment of VL are aesthetic. The haemorrhaging episodes or impairment of oral normal functions are also under considerations. Treatment of lip VL includes surgical excision, selective photocoagulation, cryotherapy, sclerotherapy and electrodessication. The high-intensity diode laser is an option. The 980 nm diode laser is selectively absorbed by haemoglobin and selectively destroys blood vessels, minimising injury to the surrounding healthy skin. The purpose of this study was to evaluate the effectiveness of diode laser in the treatment of VL lesions with the accent on the postoperative defects and aesthetic results. 35 patients aged 37 to 71 were included in this study. A 980 nm diode laser was used in noncontact mode, under local anaesthesia in continuous wave (2-3W, for 20-60s). All patients received only one procedure. Healing process was completed within 2 to 4 weeks after treatment with no scarring. None of the typical adverse effects were observed in the process of healing. Selective photocoagulation is an effective method for treatment of VL. Lower morbidity, minimal patient discomfort and satisfactory functional and aesthetic results are favourable for patients. To optimise the results and to reduce the adverse effects, basic knowledge on lasers and laser-tissue interactions is requisite.

  20. Krypton yellow laser for the treatment of macular hole in high myopia without retinal detachment.

    Cai, Ji-Ping; Cheng, Jin-Wei; Ma, Xiao-Ye; Li, Yu-Zhen; Li, You; Wei, Rui-Li

    2008-12-01

    To evaluate the prophylactic effect of krypton yellow laser for the treatment of macular holes in high myopic eyes in order to reduce the risk of retinal detachment. Twenty-seven eyes of 27 patients with high myopia and macular holes were randomly assigned to two groups. Fifteen patients (group A, 15 eyes) were subject to laser photocoagulation around the hole margin along with an oral placebo (vitamin B1), while 12 patients (group B, 12 eyes) were only given the oral placebo (vitamin B1). The incident rate of retinal detachment due to macular hole and the mean best-corrected visual acuity of the two groups before and after treatment were measured. The data were statistically tested by X2 test and Student's t test. The incident rates of retina1 detachment in group A and group B were 20%(3/15) and 58.3%(7/12), respectively (X2=4.201, P0.05). The mean BCVA of group B on the initial examination was 24/200, while the mean BCVA at the final follow-up was 30/200 (P>0.05). No significant difference in initial visual acuity (P>0.05) or final visual acuity (P>0.05) was found between the two groups. Krypton yellow laser photocoagulation could reduce the incidence of retinal detachment due to a macular hole in high myopia with acceptable functional results in this study.

  1. Improvement in retinal venous oxygen saturation after panretinal photocoagulation is predictive of progression of proliferative diabetic retinopathy

    Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin

    blood pressure was 152/84mmHg. Retinal arterial and venous saturation was 96.7% and 67.4%, respectively. Patients in Group 1 and 2 did not differ in baseline retinal arterial and venous oxygen saturation, number of laser spots delivered, total laser energy delivered, or change in retinal arterial oxygen...... patients with diagnosed PDR were included. We performed wide-field fluorescein angiography (WFA) (Optomap; Optos PLC., Dunfermline, Scotland, UK) and retinal oximetry (Oxymap model T1; Oxymap, software version 2.4.2, Reykjavik, Iceland) at baseline and three months after PRP by a navigated laser (NAVILAS...

  2. Trabeculoperforation? Trabeculoretraction? Trabeculoplasty? Review of the various designations used for laser treatment in primary open-angle glaucoma.

    Moulin, F; Haut, J; Abboud, E

    1985-01-01

    A historical recall and an attempt to simplify the numerous terms used to designate laser treatments for primary open-angle glaucoma (POAG) are presented. There are two main types of laser treatment for POAG involving two entirely different procedures. The first one, contemporary with the beginning of laser photocoagulation, imitates the action of the scalpel, namely goniotomy ab interno or trabeculotomy ab externo. The goal of this early procedure was to produce a through and through trabecular hole but instead of the cutting edge of the knife, it uses the explosive effect of the laser. This procedure has been given numerous names. Among the most frequent ones, we find: 'laser trabeculopuncture', 'laseropuncture', 'goniopuncture', 'laser trabeculectomy', 'laser trabeculotomy', 'laser trabeculopexy'. We prefer to gather them under an explicit generic term: 'laser trabeculoperforation'. The results of this procedure have been very disappointing until now, particularly with conventional lasers, e.g. continuous-wave argon laser, owing to the predominance of their thermal effect over their explosive effect and also to the great scarring property of the trabecular meshwork. In the second type of glaucoma laser treatment, instead of trying to make a patent hole in the trabecular meshwork, the surgeon seeks to reshape the inner trabecular surface by means of argon laser microscars in order to produce a reversal of the trabecular collapse, which is now considered to be one of the major etiologies of POAG.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Lasers '89

    Harris, D.G.; Shay, T.M.

    1990-01-01

    This book covers the following topics: XUV, X-Ray and Gamma-Ray Lasers, excimer lasers, chemical lasers, nuclear pumped lasers, high power gas lasers, solid state lasers, laser spectroscopy. The paper presented include: Development of KrF lasers for fusion and Nuclear driven solid-state lasers

  4. DOE Center of Excellence in Medical Laser Applications. Final report, December 1, 1994--November 30, 1997

    Jacques, S.L.

    1998-01-01

    An engineering network of collaborating medical laser laboratories are developing laser and optical technologies for medical diagnosis and therapy and are translating the engineering into medical centers in Portland OR, Houston TX, and Galveston TX. The Center includes the University of Texas M.D. Anderson Cancer Center, the University of Texas-Austin, Texas A and M University, Rice University, the University Texas Medical Branch-Galveston, Oregon Medical Laser Center (Providence St. Vincent Medical Center, Oregon Health Sciences University, and Oregon Graduate Institute, Portland, OR), and the University of Oregon. Diagnostics include reflectance, fluorescence, Raman IR, laser photoacoustics, optical coherence tomography, and several new video techniques for spectroscopy and imaging. Therapies include photocoagulation therapy, laser welding, pulsed laser ablation, and light-activated chemotherapy of cancer (photodynamic therapy, or PDT). Medical applications reaching the clinic include optical monitoring of hyperbilirubinemia in newborns, fluorescence detection of cervical dysplasia, laser thrombolysis of blood clots in heart attack and brain stroke, photothermal coagulant of benign prostate hyperplasia, and PDT for both veterinary and human cancer. New technologies include laser optoacoustic imaging of breast tumors and hemorrhage in head trauma and brain stroke, quality control monitoring of dosimetry during PDT for esophageal and lung cancer, polarization video reflectometry of skin cancer, laser welding of artificial tissue replacements, and feedback control of laser welding.

  5. Giant Retinal Tear With Retinal Detachment in Regressed Aggressive Posterior Retinopathy of Prematurity Treated by Laser.

    Chandra, Parijat; Tewari, Ruchir; Salunkhe, Nitesh; Kumawat, Devesh; Kumar, Vinod

    2017-06-29

    Rhegmatogenous retinal detachment after successfully regressed retinopathy of prematurity is a rare occurrence. Late onset rhegmatogenous retinal detachment has been reported infrequently. The authors report a case of aggressive posterior retinopathy of prematurity that underwent uneventful regression after laser photocoagulation and later developed an inoperable closed funnel retinal detachment due to a giant retinal tear. This case represents the earliest development of such complications in regressed aggressive posterior retinopathy of prematurity treated by laser. Development of a giant retinal tear has also not been previously reported after laser treatment. This case highlights that successful regression of severe retinopathy of prematurity does not safeguard against future complications and requires frequent long-term follow-up. [J Pediatr Ophthalmol Strabismus. 2017;54:e34-e36.]. Copyright 2017, SLACK Incorporated.

  6. Design and Adaptation of an Optical System for Slit Lamp Delivery of a CO2 Laser Beam.

    1981-12-01

    laser’s efficacy to serve as a photocoagulator. A non-linear barium sodium niobate crystal converted the near infrared radiation (1.064 pm) to green...recommendations. 10 II. Theoretical Development and Predictions Corneal tissue is an excellent absorber of infrared radiation. Therefore, when high power CO2...in general, that the waist will be formed slightly to one Lde of the focal plane, as shown in Eq (4) (Ref 18:31). f2 (zl-f) 2. = + wW2 (4) (zl-f) 2

  7. OUTCOMES AFTER LASER VERSUS COMBINED LASER AND BEVACIZUMAB TREATMENT FOR TYPE 1 RETINOPATHY OF PREMATURITY IN ZONE I.

    Yoon, Je Moon; Shin, Dong Hoon; Kim, Sang Jin; Ham, Don-Il; Kang, Se Woong; Chang, Yun Sil; Park, Won Soon

    2017-01-01

    To investigate the anatomical and refractive outcomes in patients with Type 1 retinopathy of prematurity in Zone I. The medical records of 101 eyes of 51 consecutive infants with Type 1 retinopathy of prematurity in Zone I were analyzed. Infants were treated by conventional laser photocoagulation (Group I), combined intravitreal bevacizumab injection and Zone I sparing laser (Group II), or intravitreal bevacizumab with deferred laser treatment (Group III). The proportion of unfavorable anatomical outcomes including retinal fold, disc dragging, retrolental tissue obscuring the view of the posterior pole, retinal detachment, and early refractive errors were compared among the three groups. The mean gestational age at birth and the birth weight of all 51 infants were 24.3 ± 1.1 weeks and 646 ± 143 g, respectively. In Group I, an unfavorable anatomical outcome was observed in 10 of 44 eyes (22.7%). In contrast, in Groups II and III, all eyes showed favorable anatomical outcomes without reactivation or retreatment. The refractive error was less myopic in Group III than in Groups I and II (spherical equivalent of -4.62 ± 4.00 D in Group I, -5.53 ± 2.21 D in Group II, and -1.40 ± 2.19 D in Group III; P prematurity in Zone I, intravitreal bevacizumab with concomitant or deferred laser therapy yielded a better anatomical outcome than conventional laser therapy alone. Moreover, intravitreal bevacizumab with deferred laser treatment resulted in less myopic refractive error.

  8. Twin-twin transfusion syndrome: neurodevelopment of infants treated with laser surgery

    Denise Campos

    2016-04-01

    Full Text Available ABSTRACT Objective To assess the neurodevelopmental functions of survivors of twin-twin transfusion syndrome (TTTS treated by fetoscopic laser coagulation (FLC, during the first year of life, comparing them to a control group; and to verify the influence of specific variables on neurodevelopment. Method This was a prospective, longitudinal study. The sample comprised 33 monochorionic diamniotic twins who underwent FLC for treatment of TTTS and 22 full-term infants of single-fetus pregnancies. Bayley Scales of Infant and Toddler Development Screening Test were used for evaluation. Prenatal, perinatal and postnatal information were obtained. Results There was an increased frequency of infants in the TTTS group with inadequate performance compared to the control group. The identified variables (fetal donor, low economic income and cardiorespiratory disease negatively impacted expressive communication and fine motor skills. Conclusion Although through follow-up is recommended in all TTTS survivors, particular attention is required for the high-risk group as defined in this study.

  9. Early rhegmatogenous retinal detachment following laser in situ keratomileusis for high myopia.

    Farah, M E; Höfling-Lima, A L; Nascimento, E

    2000-01-01

    Four eyes had early rhegmatogenous retinal detachment within 3 months of laser in situ keratomileusis (LASIK) for correction of high myopia using the microkeratome, Clear Corneal Molder. In two eyes, retinal detachment resulted from horseshoe tears, one occurring in an otherwise normal region of the retina and the other at the margin of an area of lattice degeneration detected during preoperative examination. The first eye was treated with retinopexy using a 287 encircling scleral exoplant, drainage of subretinal fluid, and laser photocoagulation by indirect ophthalmoscopy. The other eye was treated with pneumatic retinopexy and cryotherapy. In the other eyes, retinal detachment was the result of giant tears with no evidence of prior retinal degeneration. These eyes were treated with pars plana vitrectomy, fluid-gas exchange with 15% perfluoropropane (C3F8), endolaser photocoagulation, and a 42 encircling scleral exoplant. After treatment, the first two eyes achieved spectacle-corrected visual acuity of 20/40. In the last two eyes, final spectacle-corrected visual acuity was 20/400 in one eye and light perception in the other. Although no cause-effect relationship between LASIK and retinal detachment can be stated, these cases suggest that LASIK may be associated with retinal detachment, particularly in highly myopic eyes. Further studies are necessary to determine high-risk patient characteristics.

  10. Laser treatment of drusen to prevent progression to advanced age-related macular degeneration.

    Virgili, Gianni; Michelessi, Manuele; Parodi, Maurizio B; Bacherini, Daniela; Evans, Jennifer R

    2015-10-23

    Drusen are amorphous yellowish deposits beneath the sensory retina. People with drusen, particularly large drusen, are at higher risk of developing age-related macular degeneration (AMD). The most common complication in AMD is choroidal neovascularisation (CNV), the growth of new blood vessels in the centre of the macula. The risk of CNV is higher among people who are already affected by CNV in one eye.It has been observed clinically that laser photocoagulation of drusen leads to their disappearance and may prevent the occurrence of advanced disease (CNV or geographic atrophy) associated with visual loss. To examine the effectiveness and adverse effects of laser photocoagulation of drusen in AMD. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015, Issue 7), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2015), EMBASE (January 1980 to August 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to August 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 3 August 2015. Randomised controlled trials (RCTs) of laser treatment of drusen in AMD in which laser treatment had been compared with no intervention or sham treatment. Two types of trials were included. Some trials studied one eye of each participant (unilateral studies); other studies recruited participants with bilateral drusen and randomised one eye to photocoagulation or control and the fellow eye to the other group. Two review authors independently selected studies and extracted data. We pooled data from unilateral and bilateral

  11. Treatment of extensive urethral hemangioma with KTP/532 laser.

    Lauvetz, R W; Malek, R S; Husmann, D A

    1996-01-01

    Urethral hemangiomas are rare. They vary in size from pinpoint masses to extensive honeycomb-shape deformities leading to significant hematuria. For extensive lesions, therapeutic options have included extensive surgical resection and reconstruction or multistaged neodymium:yttrium-aluminum-garnet (Nd:YAG) laser photocoagulation. We report our experience with the use of potassium titanyl phosphate (KTP/532) laser for treatment of the extensive form. A 7-year-old boy presented with a 2-week history of urethral bleeding. He had extensive hemangiomas of the genital and perineal regions. Cystourethroscopy disclosed diffusely scattered honeycomb-shape hemangiomatous malformation of the anterior urethra. KTP/532 laser energy was delivered transurethrally to the hemangiomatous areas until they blanched. The Foley catheter was removed 24 hours postoperatively, and the patient voided clear urine without difficulty. He has remained trouble-free for more than 2 years. Judicious endoscopic single-stage therapy with KTP/532 laser may obviate open surgical intervention in most cases of extensive and symptomatic urethral hemangiomas. In view of our observation and the literature, KTP/532 laser therapy should be considered the first line of treatment.

  12. Study of krypton laser-induced choroidal neovascularization in a Guinea pig model of high anisometropia.

    Wang, Jianghui; Jiang, Wei; Kang, Zefeng; Liang, Lina; Liu, Xiaoman; Tian, Nannan; Zhang, Qing

    2012-06-01

    To investigate the association between high anisometropia and the area of choroidal neovascularization (CNV) induced by krypton laser in guinea pigs and better understand the pathogenesis and prevention of myopic CNV. Nine 3-week old male guinea pigs with anisometropia >6.00D were randomly assigned to three groups according to examination date after laser photocoagulation (7d, 14d and 28d). All animals underwent refraction. The eye with higher myopia was used as the experimental eye, and the other as the control eye. All eyes received repeated multi-wavelength krypton laser photocoagulation treatments (wavelength: 532nm; laser power: 400mW; spot diameter: 50μm; exposure time: 0.1s). Fundus photography and indocyanine green angiography (ICGA) were performed. Afterwards, the animals were sacrificed immediately, and the eyes were enucleated and processed for histopathologic examination and flat mounts. CNV appeared at 7d after laser treatment. The area of CNV peaked at 14d, and decrease in area and the presence of scarring was noted at 28 d. CNV was present in 66.7% of eyes by ICGA at 14 d. CNV could be observed under light microscopy at all three time points. At 14d, flat mount showed the neovascular plexus around the lesion. Semi-quantitative analysis revealed that the area of CNV in treated eyes was greater than that of control eyes. Since the mechanism of CNV in this study resembles that of CNV in pathological myopia, this model can be used to investigate the etiology, pathogenesis and treatment of CNV in pathological myopia.

  13. Effect of Conbercept injection and macular grid pattern photocoagulation in treating macular edema after non-ischemic branch retinal vein occlusion

    Jiang Zhu

    2018-06-01

    Full Text Available AIM: To investigate the effects and safety of intravitreal injection of Conbercept combined with macular grid pattern photocoagulation for macular edema secondary to non-ischemic branch retinal vein occlusion(BRVO. METHODS: A total of 38 patients(38 eyes with macular edema following non-ischemic BRVO were retrospectively analyzed. All patients were given best corrected visual acuity(BCVA, intraocular pressure, slit lamp with preset lens, optic coherent tomography(OCTand fluorescence fundus angiography(FFAexamination. The BCVA and central macular thickness(CMTwere observed before and 1wk, 1, 2, 3, 6, 9 and 12mo after treatment. The change in pre-treatment and post-treatment were compared, and the related complications were recorded. RESULTS:BCVA before treatment and 1wk, 1, 2, 3, 6, 9 and 12mo after treatment were 0.89±0.62, 0.64±0.59, 0.55±0.62, 0.46±0.43, 0.53±0.67, 0.43±0.38, 0.42±0.29, 0.40±0.30, the difference was statistically significant between that before and after treatment(PP>0.05. CMT were 683.25±236.47, 298.65±116.12, 276.89±107.28, 281.55±99.62, 251.41±119.47, 240.58±88.62, 231.74±75.36, 209.51±84.68μm, the difference was statistically significant between that before and after treatment(PP>0.05. There were 11 eyes received one injection, 18 eyes with two injections, 2 eyes with 3, 3 eyes with 4, and 4 eyes more than 4, the average injection was 2.01±1.42. The CMT decreased after every injection. The intraocular hypertension and other complications were not seen after treatment. CONCLUSION: Intravitreal injection of conbercept combined with macular grid pattern photocoagulation for macular edema to non-ischemic BRVO can reduce the macular edema and improve BCVA, which is effective and safety.

  14. Laser therapy and sclerotherapy in the treatment of oral and maxillofacial hemangioma and vascular malformations

    Crişan, Bogdan; BǎciuÅ£, Mihaela; BǎciuÅ£, Grigore; Crişan, Liana; Bran, Simion; Rotar, Horatiu; Moldovan, Iuliu; Vǎcǎraş, Sergiu; Mitre, Ileana; Barbur, Ioan; Magdaş, Andreea; Dinu, Cristian

    2016-03-01

    Hemangioma and vascular malformations in the field of oral and maxillofacial surgery is a pathology more often found in recent years in patients. The aim of this study was to evaluate the efficacy of the laser photocoagulation performed with a diode laser (Ga-Al-As) 980 nm wavelength in the treatment of vascular lesions which are located on the oral and maxillofacial areas, using color Doppler ultrasonography for evaluation of the results. We also made a comparison between laser therapy and sclerotherapy in order to establish treatment protocols and recommendations associated with this pathology. We conducted a controlled study on a group of 92 patients (38 male and 54 female patients, with an average age of 36 years) having low flow hemangioma and vascular malformations. Patients in this trial received one of the methods of treatment for vascular lesions such as hemangioma and vascular malformations: laser therapy or sclerotherapy. After laser therapy we have achieved a reduction in size of hemangioma and vascular malformations treated with such a procedure, and the aesthetic results were favorable. No reperfusion or recanalization of laser treated vascular lesions was observed after an average follow-up of 6 to 12 months. In case of sclerotherapy a reduction in the size of vascular lesions was also obtained. The 980 nm diode laser has been proved to be an effective tool in the treatment of hemangioma and vascular malformations in oral and maxillofacial area. Laser therapy in the treatment of vascular lesions was more effective than the sclerotherapy procedure.

  15. Laser treatment of oral vascular malformations

    Romeo, U.; Gaimari, G.; Mohsen, M.; Tenore, G.; Palaia, G.

    2014-01-01

    Oral Vascular Malformations (OVM) are congenital anomalies characterized by morph-structural and/or functional changes of nature in severity and extension. OVM can affect any type of vessels arterial, venous or lymphatic and any capillary or anatomical. They are divided into two categories: low and high flow. In this study were treated 40 patients with OVM with a range size from 2 mm to 44 mm; they were subjected to clinical examination supported by Colour-Doppler Ultrasound instrumental examination and only for doubt cases the Magnetic Resonance Imaging (MRI) was prescribed. Only low flow venous and capillary malformations were treated by GaAlAs laser (Wiser®, Lambda, Brindole,Italy, 980nm) and KTP laser (SmartLite®, DEKA, Florence, Italy, 532nm) with two different techniques: the Transmucosal Thermophotocoagulation (TMT) and the Intralesional Photocoagulation (ILP). These techniques permitted a good control of haemostasis, avoiding bleeding both during surgery and in the postoperative. It is obtained an excellent and good healing respectively in 10% and 60% of cases, a moderate and poor resolution respectively in 22.5% and 7.5% of cases. A clear diagnosis allowed the management of Venous malformations (VM) by laser devices with wavelengths highly absorbed in haemoglobin in safety and efficacy and according to the principles of minimal invasive surgery. The aim of this study was to verify if the laser is effective in the treatment of OVM for the purpose of the clinical findings and the postoperative course. The Authors concluded that the laser can be considered the "gold standard" for treating OVM.

  16. 1.9 W yellow, CW, high-brightness light from a high efficiency semiconductor laser-based system

    Hansen, Anders Kragh; Christensen, Mathias; Noordegraaf, Danny

    2017-01-01

    Semiconductor lasers are ideal sources for efficient electrical-to-optical power conversion and for many applications where their small size and potential for low cost are required to meet market demands. Yellow lasers find use in a variety of bio-related applications, such as photocoagulation......, imaging, flow cytometry, and cancer treatment. However, direct generation of yellow light from semiconductors with sufficient beam quality and power has so far eluded researchers. Meanwhile, tapered semiconductor lasers at near-infrared wavelengths have recently become able to provide neardiffraction...... power in just 60 seconds. An advantage of using a single pass configuration, rather than an external cavity configuration, is increased stability towards external perturbations. For example, stability to fluctuating case temperature over a 30 K temperature span has been demonstrated. The combination...

  17. Intra- and inter-grader agreement in grading of coverage of panretinal photocoagulation by ultra-wide field color fundus images

    Torp, Thomas Lee; Jakobsen, Ditte Borup; Grauslund, Jakob

    , and each grader evaluated the total retinal area covered by laser. The graders categorized the amount of laser visible on the retina into four categories (no visible laser spots, laser was 76-100% (for both graders). Intra-grader association...

  18. Laser Technology.

    Gauger, Robert

    1993-01-01

    Describes lasers and indicates that learning about laser technology and creating laser technology activities are among the teacher enhancement processes needed to strengthen technology education. (JOW)

  19. 激光治疗糖尿病视网膜病变的疗效观察%Laser treatment for diabetic retinopathy

    张未来; 陈蕾

    2008-01-01

    目的 探讨激光治疗糖尿病视网膜病变的效果.方法 根据DRPSG(Diabetic Retinopathy Photocoagulation Study Group)制定的治疗技术规定,对280例365只眼分别为增殖前期糖尿病视网膜病变(Preproliferative diabetic retinopathy,PPDR)、增殖期糖尿病视网膜病变(Proliferative diabetic retinopathy,PDR)及糖尿病性黄斑水肿(Diabetic macular edema,DME)患者,分别行标准全视网膜光凝(S-PRP)、超全视网膜光凝(E-PRP)、局限或格栅光凝.术后3、6、12个月行FFA及彩色眼底像,新生血管未消退者和无灌注区尚存者追加光凝,随访3~36个月.结果 355只眼行全视网膜光凝,新生血管或无灌注区全部或部分消退256只眼,有效率为72.1%:视力不变和增进292只眼,占82.3%;35只黄斑水肿眼局限或格栅光凝后,26只眼水肿减轻或消失,有效率74.3%.结论 激光治疗糖尿病性视网膜病变安全有效.%Objective To evaluate the technique of laser treatment for diabetic retinopathy.Methods According to the treatment technique stipulations formulated by DRPSG (Diabetic Retinopathy photo coagulation Study Group),365 eyes of 280 patients suffering from preprcliferative diabetic retinopathy(PPDR), proliferative diabetic retinopathy (POR) and diabetic macular edema (DME) repectively were treated with laser treatment.These patients received the treatment of standard panretinal photocoagulation(S-PRP) and extra panretinal photocoagulation (E-PRP).Those with macular edema received the focal and grid photocoagulation.The fundus fluorescein angio graphy (FFA)and color photograph were taken 3,6 and12 months after the treatment.For those cases with remaining new vessels and non-perfusion areas, the treatment was complemented with further photocoagulation. The follow-up period was 3~36 months. Results Retinal new vessels partly or entirely regressed in 256 eyes (about 72.1%)of the 355 eyes subjected to PRP. Visual acuity were improved or maintained in 292 eyes

  20. [Partial regression of Barret esophagus with high grade dysplasia and adenocarcinoma after photocoagulation and endocurietherapy under antisecretory treatment].

    Fremond, L; Bouché, O; Diébold, M D; Demange, L; Zeitoun, P; Thiefin, G

    1995-01-01

    Barrett's oesophagus is a premalignant condition. The possibility of eradicating at least partially the metaplastic epithelium has been reported recently. In this case report, a patient with Barrett's oesophagus complicated by high grade dysplasia and focal adenocarcinoma was treated by Nd:Yag laser then high dose rate intraluminal irradiation while on omeprazole 40 mg/day. A partial eradication of Barrett's oesophagus and a transient tumoural regression were obtained. Histologically, residual specialized-type glandular tissue was observed beneath regenerative squamous epithelium. Four months after intraluminal irradiation, a local tumoural recurrence was detected while the area of restored squamous epithelium was unchanged on omeprazole 40 mg/day. This indicates that physical destruction of Barrett's oesophagus associated with potent antisecretory treatment can induce a regression of the metaplastic epithelium, even in presence of high grade dysplasia. The persistence of specialized-type glands beneath the squamous epithelium raises important issues about its potential malignant degeneration.

  1. Krypton laser treatment of neovascularization in retinal vein occlusion%氪激光治疗视网膜静脉阻塞的新生血管

    吴又凯; 武志峰; 张清

    2001-01-01

    Objective To investigate the method and effect of krypton laser photocoagulation for neovascularization in retinal vein occlusion. Methods Tweenty eight eyes of 27 patients with retinal vein occlusion with neovascularization were photocoagulated by krypton-green and-red laser.The fundus changes were observed by fundus fluorescein angiography after photocoagulation. Results The neovascularization disappeared completely in 20 eyes and became smaller in 6 eyes,remained no-change in 2 eyes,and the visual acuity improved in 17 eyes (60.7%) after 6 monthes to 2.5 years of follow-up. Conclusion Krypton laser photocoagulation is obviously effective on regression of neovascularization and prevenion of vitreous hemorrhage in retinal vein occlusion.%目的探讨氪激光治疗视网膜静脉阻塞新生血管的方法和疗效。方法对27例视网膜静脉阻塞伴有新生血管的28只患眼采用氪绿、氪红激光进行光凝治疗。光凝后经6个月~2.5年随访,对比分析光凝前后的荧光素眼底血管造影及视力变化情况。结果新生血管萎缩20只眼,占71.4%,好转6只眼,占21.4%,无效2只眼,占7.2%。视力进步17只眼,占60.7%。结论氪激光光凝术对视网膜静脉阻塞新生血管的消退及预防其玻璃体积血具有显著疗效。

  2. Optimization of an Image-Guided Laser-Induced Choroidal Neovascularization Model in Mice.

    Yan Gong

    Full Text Available The mouse model of laser-induced choroidal neovascularization (CNV has been used in studies of the exudative form of age-related macular degeneration using both the conventional slit lamp and a new image-guided laser system. A standardized protocol is needed for consistent results using this model, which has been lacking. We optimized details of laser-induced CNV using the image-guided laser photocoagulation system. Four lesions with similar size were consistently applied per eye at approximately double the disc diameter away from the optic nerve, using different laser power levels, and mice of various ages and genders. After 7 days, the mice were sacrificed and retinal pigment epithelium/choroid/sclera was flat-mounted, stained with Isolectin B4, and imaged. Quantification of the area of the laser-induced lesions was performed using an established and constant threshold. Exclusion criteria are described that were necessary for reliable data analysis of the laser-induced CNV lesions. The CNV lesion area was proportional to the laser power levels. Mice at 12-16 weeks of age developed more severe CNV than those at 6-8 weeks of age, and the gender difference was only significant in mice at 12-16 weeks of age, but not in those at 6-8 weeks of age. Dietary intake of omega-3 long-chain polyunsaturated fatty acid reduced laser-induced CNV in mice. Taken together, laser-induced CNV lesions can be easily and consistently applied using the image-guided laser platform. Mice at 6-8 weeks of age are ideal for the laser-induced CNV model.

  3. Efficacy and safety of intravitreal ranibizumab with panretinal photocoagulation followed by trabeculectomy compared with Ahmed glaucoma valve implantation in neovascular glaucoma

    Jin-Tao Sun

    2017-03-01

    Full Text Available AIM: To evaluate the efficacy and safety of intravitreal ranibizumab (IVR with panretinal photocoagulation (PRP followed by trabeculectomy compared with Ahmed glaucoma valve (AGV implantation in neovascular glaucoma (NVG. METHODS: This was a retrospective comparative study. We reviewed the cases of a total of 45 eyes from 45 NVG patients among which 23 eyes underwent AGV implantation and the other 22 underwent trabeculectomy. The causes of neovascular glaucoma included: diabetic retinopathy (25 eyes, and retinal vein occlusion (20 eyes. All patients received preoperative IVR combined with postoperative PRP. The mean best-corrected visual acuities (BCVA were converted to the logarithms of the minimum angle of resolution (logMAR for the statisitical analyses. Intraocular pressure (IOP, the logMAR BCVA and surgical complications were evaluated before and after surgery. The follow-up period was 12mo. RESULTS: A total of 39 cases showed complete regression of iris neovascularization at 7d after injection, and 6 cases showed a small amount of residual iris neovascularization. The success rates were 81.8% and 82.6% at 12mo after trabeculectomy and AGV implantation, respectively. In the trabeculectomy group, the logMAR BCVA improved at the last follow-up in 14 eyes, remained stable in 6 eyes and decreased in 2 eyes. In 4 cases, slight hyphemas developed after trabeculectomy. A shallow anterior chamber developed in 2 cases and 2 vitreous hemorrhages. In the AGV group, the logMAR BCVA improved in 14 eyes, remained stable in 5 eyes and decreased in 4 eyes. Slight hyphemas developed in 3 cases, and a shallow anterior chamber in 3 cases. The mean postoperative IOP was significantly lower in both groups after surgery (F=545.468, P<0.05, and the mean postoperative logMAR BCVA was also significantly improved (F=10.964, P<0.05 with no significant difference between two groups. CONCLUSION: It is safe and effective to treat NVG with this combined procedure, and we

  4. Dual Use of Image Based Tracking Techniques: Laser Eye Surgery and Low Vision Prosthesis

    Juday, Richard D.; Barton, R. Shane

    1994-01-01

    With a concentration on Fourier optics pattern recognition, we have developed several methods of tracking objects in dynamic imagery to automate certain space applications such as orbital rendezvous and spacecraft capture, or planetary landing. We are developing two of these techniques for Earth applications in real-time medical image processing. The first is warping of a video image, developed to evoke shift invariance to scale and rotation in correlation pattern recognition. The technology is being applied to compensation for certain field defects in low vision humans. The second is using the optical joint Fourier transform to track the translation of unmodeled scenes. Developed as an image fixation tool to assist in calculating shape from motion, it is being applied to tracking motions of the eyeball quickly enough to keep a laser photocoagulation spot fixed on the retina, thus avoiding collateral damage.

  5. The Newest Laser Processing

    Lee, Baek Yeon

    2007-01-01

    This book mentions laser processing with laser principle, laser history, laser beam property, laser kinds, foundation of laser processing such as laser oscillation, characteristic of laser processing, laser for processing and its characteristic, processing of laser hole including conception of processing of laser hole and each material, and hole processing of metal material, cut of laser, reality of cut, laser welding, laser surface hardening, application case of special processing and safety measurement of laser.

  6. Laser cladding assisted by friction stir processing for preparation of deformed crack-free Ni-Cr-Fe coating with nanostructure

    Xie, Siyao; Li, Ruidi; Yuan, Tiechui; Chen, Chao; Zhou, Kechao; Song, Bo; Shi, Yusheng

    2018-02-01

    Although laser cladding has find its widespread application in surface hardening, this technology has been significantly limited by the solidification crack, which usually initiates along grain boundary due to the brittle precipitation in grain boundary and networks formation during the laser rapid melting/solidification process. This paper proposed a novel laser cladding technology assisted by friction stir processing (FSP) to eliminate the usual metallurgical defects by the thermomechanical coupling effect of FSP with the Ni-Cr-Fe as representative coating material. By the FSP assisted laser cladding, the crack in laser cladding Ni-Cr-Fe coating was eliminated and the coarse networks of laser cladding coating was transformed into dispersed nanoparticles. Moreover, the plastic layers with thicknesses 47-140 μm can be observed, with gradient grain refinement from substrate to the top surface in which grain size reached 300 nm and laser photocoagulation net second phase crushed in the layer. In addition, cracks closed in the plastic zone. The refinement of grain resulted the hardness increased to over 400 HV, much higher than the 300 HV of the laser cladding structure. After FSP, the friction coefficient decreased from 0.6167 to 0.5645 which promoted the wear resistance.

  7. Aggressive posterior retinopathy of prematurity in Asian Indian babies: spectrum of disease and outcome after laser treatment.

    Sanghi, Gaurav; Dogra, Mangat R; Das, Pranab; Vinekar, Anand; Gupta, Amod; Dutta, Saurabh

    2009-10-01

    To analyze the spectrum of aggressive posterior retinopathy of prematurity and outcome after laser treatment. This is a retrospective review of 81 eyes of 44 consecutive infants diagnosed to have aggressive posterior retinopathy of prematurity and treated between September 2005 and March 2007 from a large tertiary care center in North India. Qualitative variables were tested for statistical significance using the chi-square test and independent samples with the student's t-test. Mean birth weight and gestational age were 1,259.66 +/- 310.51 g (range, 660-2,000 g) and 29.75 +/- 2.35 weeks (range, 26-36 weeks), respectively. Twenty-one infants (47.72%) had a birth weight > 1,250 g. Thirty-three (40.74%) eyes had Zone 1, and 48 (59.26%) had posterior Zone 2 disease. All eyes underwent confluent laser photocoagulation at a mean postconceptional age of 34.58 +/- 2.19 weeks (range, 31-40.5 weeks). Mean follow-up was 12.8 months (range, 6-24 months). At the last follow-up visit, 55 (71.4%) of 77 eyes had a favorable outcome. Eighteen eyes (23.4%) had a localized (1-3 clock hours) partial peripheral tractional detachment (Stage 4a), which remained stable at last follow-up. Two eyes (2.6%) developed falciform fold involving the macular area, and 2 (2.6%) developed Stage 5 retinopathy of prematurity. Aggressive posterior retinopathy of prematurity is encountered not only in low birth weight infants, but also in heavier and more mature Asian Indian infants. Early, aggressive confluent laser photocoagulation is necessary to maximize outcomes in these eyes.

  8. Diode laser assisted minimal invasive sphenoidotomy for endoscopic transphenoidal pituitary surgery: our technique and results.

    Lee, Jih-Chin; Lai, Wen-Sen; Ju, Da-Tong; Chu, Yueng-Hsiang; Yang, Jinn-Moon

    2015-03-01

    During endoscopic sinus surgery (ESS), intra-operative bleeding can significantly compromise visualization of the surgical field. The diode laser that provides good hemostatic and vaporization effects and excellent photocoagulation has been successfully applied in endoscopic surgery with several advantages. The current retrospective study demonstrates the feasibility of diode laser-combined endoscopic sinus surgery on sphenoidotomy. The patients who went through endoscopic transphenoidal pituitary surgery were enrolled. During the operation, the quality of the surgical field was assessed and graded by the operating surgeon using the scale proposed by Boezaart. The mean operation time was 37.80 ± 10.90 minutes. The mean score on the quality of surgical field was 1.95. A positive correlation between the lower surgical field quality score and the shorter surgical time was found with statistical significance (P diode laser-assisted sphenoidotomy is a reliable and safe approach of pituitary gland surgery with minimal invasiveness. It is found that application of diode laser significantly improved quality of surgical field and shortened operation time. © 2015 Wiley Periodicals, Inc.

  9. Orofacial lymphatic malformation: management with a three steps diode laser protocol

    Miccoli, Simona; Tempesta, Angela; Limongelli, Luisa; Caporusso, Concetta; Di Venere, Daniela; Petruzzi, Massimo; Lacaita, Mariagrazia; Maiorano, Eugenio; Favia, Gianfranco

    2014-01-01

    Lymphatic Malformation (LM) according to ISSVA Classification, is a rare benign disorder with unknown aetiology. LM may grow slowly over years or develop rapidly over the course of days becoming a bulky lump, infected or bleeding. We propose our three steps Diode Laser protocol for LM management, based on its persistent vascular blood component. 1. Histological and cytological examination, to evaluate the vascular blood component (10-40%), shows mature lymphocytes with red blood cells and endothelial cells. 2. Diode Laser Photocoagulation (DLP) in pulsed mode (on 100ms / off 400ms) at 10W and 800nm with a 300μm fibre kept 2-3mm from the tissues, to reduce the lesion. 3. Diode Laser surgical excision in pulsed mode (on 50ms / off 200ms) at 8W and 800nm with a 300 μm fibre in close contact with tissues, and histological intraoperative margins control on frozen sections. Even if it has inconstant results (lesions decreasing rate is 10% to 40% proportionally to vascular blood component), DLP simplifies the last and the most important step. Use of Diode Laser also in surgical excision reduces intra and postoperatory complications.

  10. The neuroprotective effect of hyperbaric oxygen treatment on laser-induced retinal damage in rats

    Vishnevskia-Dai, Victoria; Belokopytov, Mark; Dubinsky, Galina; Nachum, Gal; Avni, Isaac; Belkin, Michael; Rosner, Mordechai

    2005-04-01

    Retinal damage induced by mechanical trauma, ischemia or laser photocoagulation increases considerably by secondary degeneration processes. The spread of damage may be ameliorated by neuroprotection that is aimed at reducing the extent of the secondary degeneration and promote healing processes. Hyperbaric oxygen (HBO) treatment consists of inspiration of oxygen at higher than one absolute atmospheric pressure. Improved neural function was observed in patients with acute brain trauma or ischemia treated with HBO. This study was designed to evaluate the neuroprotective effect of hyperbaric oxygen (HBO) on laser induced retinal damage in a rat model. Standard argon laser lesions were created in 25 pigmented rats divided into three groups: Ten rats were treated immediately after the irradiation with HBO three times during the first 24 hr followed by 12 consecutive daily treatments. Five rats received a shorter treatment regimen of 10 consecutive HBO treatments. The control group (10 rats) underwent the laser damage with no additional treatment. The retinal lesions were evaluated 20 days after the injury. All outcome measures were improved by the longer HBO treatment (Ptreatment was less effective, showing an increase only in nuclei density at the central area of lesion (Pretinal damage in a rat model. In the range of HBO exposures studied, longer exposure provides more neuroprotection. These results encourage further evaluation of the potential therapeutic use of hyperbaric oxygen in diseases and injuries of the retina.

  11. Therapeutic Effect of Bone Marrow Mesenchymal Stem Cells on Laser-Induced Retinal Injury in Mice

    Yuanfeng Jiang

    2014-05-01

    Full Text Available Stem cell therapy has shown encouraging results for neurodegenerative diseases. The retina provides a convenient locus to investigate stem cell functions and distribution in the nervous system. In the current study, we investigated the therapeutic potential of bone marrow mesenchymal stem cells (MSCs by systemic transplantation in a laser-induced retinal injury model. MSCs from C57BL/6 mice labeled with green fluorescent protein (GFP were injected via the tail vein into mice after laser photocoagulation. We found that the average diameters of laser spots and retinal cell apoptosis were decreased in the MSC-treated group. Interestingly, GFP-MSCs did not migrate to the injured retina. Further examination revealed that the mRNA expression levels of glial fibrillary acidic protein and matrix metalloproteinase-2 were lower in the injured eyes after MSC transplantation. Our results suggest that intravenously injected MSCs have the ability to inhibit retinal cell apoptosis, reduce the inflammatory response and limit the spreading of damage in the laser-injured retina of mice. Systemic MSC therapy might play a role in neuroprotection, mainly by regulation of the intraocular microenvironment.

  12. Laser Therapy

    ... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Laser Resurfacing Uses for Laser Resurfacing Learn more ...

  13. Lasers technology

    2014-01-01

    The Laser Technology Program of IPEN is developed by the Center for Lasers and Applications (CLA) and is committed to the development of new lasers based on the research of new optical materials and new resonator technologies. Laser applications and research occur within several areas such as Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. Additional goals of the Program are human resource development and innovation, in association with Brazilian Universities and commercial partners

  14. YCOB lasers

    Richardson, Martin; Hammons, Dennis; Eichenholz, Jason; Chai, Bruce; Ye, Qing; Jang, Won; Shah, Lawrence

    1999-01-01

    We review new developments with a new laser host material, YCa 4 O(BO 3 ) 3 or YCOB. Lasers based on this host material will open new opportunities for the development of compact, high-power, frequency-agile visible and near IR laser sources, as well as sources for ultrashort pulses. Efficient diode-pumped laser action with both Nd-doped and Yb-doped YCOB has already been demonstrated. Moreover, since these materials are biaxial, and have high nonlinear optical coefficients, they have become the first laser materials available as efficient self-frequency-doubled lasers, capable of providing tunable laser emission in several regions of the visible spectrum. Self-frequency doubling eliminates the need for inclusion of a nonlinear optical element within or external to the laser resonator. These laser materials possess excellent thermal and optical properties, have high laser-damage thresholds, and can be grown to large sizes. In addition they are non-hygroscopic. They therefore possess all the characteristics necessary for laser materials required in rugged, compact systems. Here we summarize the rapid progress made in the development of this new class of lasers, and review their potential for a number of applications. (author)

  15. Laser sampling

    Gorbatenko, A A; Revina, E I

    2015-01-01

    The review is devoted to the major advances in laser sampling. The advantages and drawbacks of the technique are considered. Specific features of combinations of laser sampling with various instrumental analytical methods, primarily inductively coupled plasma mass spectrometry, are discussed. Examples of practical implementation of hybrid methods involving laser sampling as well as corresponding analytical characteristics are presented. The bibliography includes 78 references

  16. HF laser

    Suzuki, Kazuya; Iwasaki, Matae

    1977-01-01

    A review is made of the research and development of HF chemical laser and its related work. Many gaseous compounds are used as laser media successfully; reaction kinetics and technological problems are described. The hybrid chemical laser of HF-CO 2 system and the topics related to the isotope separation are also included. (auth.)

  17. Toward the development of a low-cost laser Doppler module for ophthalmic microscopes

    Cattini, Stefano; Rovati, Luigi

    2012-03-01

    A laser Doppler module easily integrated into a commercial ophthalmic microscope is proposed. Such setup adds flow measurement capability to standard visual inspection of the fundus. The proposed instrument may provide important clinical information such as the detection of vessel occlusion provided by surgical treatments (i.e. photocoagulation). The measuring system is based on a self-mixing laser diode Doppler flowmeter (SM-DF). Reduced costs, easy implementation and small size represent the main features of SM-DF. Moreover, this technique offers the advantage to have the excitation and measurement beams spatially overlapped, thus both overcoming the alignment difficulty of traditional laser Doppler flowmeter and, well fitting with to limited optical aperture of the pupil. Thanks to an on-board DSP-microcontroller, the optoelectronic module directly estimates the blood flow; USB connection and an ad-hoc developed user-friendly software interface allow displaying the result on a personal computer. Preliminary test demonstrates the applicability of the proposed measuring system.

  18. Histopathology of the effects of tuneable dye laser on monkey retina

    Smiddy, W.E.; Patz, A.; Quigley, H.A.; Dunkelberger, G.R.

    1988-07-01

    The tuneable dye laser was used to simulate treatment of choroidal neovascularization and panretinal photocoagulation (PRP) in monkey retina. The histopathologic effects of wavelengths from 560 to 630 nm in juxtafoveal, papillomacular bundle, and nonfoveal areas were investigated. An unexpected observation using high-intensity burns in juxtafoveal and, to a lesser extent, in papillomacular bundle areas was inner retinal damage with 600-nm light. At moderate energy levels, the effect of 600 nm were more comparable with those with other wavelengths and included much less damage to the inner retinal layers. At mild energy levels, the effects were comparable with other wavelengths. During and after the application of the burns, the energy levels and ophthalmoscopic appearances were comparable for each wavelength for the high-, moderate-, and mild-intensity burns. The histopathologic effects of 630-nm light (tuneable dye red) were comparable with those of the standard krypton red (647 nm) laser. Nonmacular and PRP effects were similar with all wavelengths. These results indicate that power levels may need to be reduced when placing 600-nm (orange) laser burns in the macula.

  19. Laser fusion

    Eliezer, S.

    1982-02-01

    In this paper, the physics of laser fusion is described on an elementary level. The irradiated matter consists of a dense inner core surrounded by a less dense plasma corona. The laser radiation is mainly absorbed in the outer periphery of the plasma. The absorbed energy is transported inward to the ablation surface where plasma flow is created. Due to this plasma flow, a sequence of inward going shock waves and heat waves are created, resulting in the compression and heating of the core to high density and temperature. The interaction physics between laser and matter leading to thermonuclear burn is summarized by the following sequence of events: Laser absorption → Energy transport → Compression → Nuclear Fusion. This scenario is shown in particular for a Nd:laser with a wavelength of 1 μm. The wavelength scaling of the physical processes is also discussed. In addition to the laser-plasma physics, the Nd high power pulsed laser is described. We give a very brief description of the oscillator, the amplifiers, the spatial filters, the isolators and the diagnostics involved. Last, but not least, the concept of reactors for laser fusion and the necessary laser system are discussed. (author)

  20. Biocavity Lasers

    Gourley, P.L.; Gourley, M.F.

    2000-10-05

    Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

  1. Argon laser in the treatment of diabetic retinopathy (Preliminary communication)

    Saprykin, P.I.; Simonova, K.K.; Belyaeva, M.I.

    1974-01-01

    The complications observed in the photocoagulation treatment of diabetic angiopathy and retinopathy include the following conditions: tractional retinal detachment, accelerated development of proliferating retinitis and massive hemmorrhaging into the vitreous body. (V.A.P.)

  2. Pain score of patients undergoing single spot, short pulse laser versus conventional laser for diabetic retinopathy.

    Mirshahi, Ahmad; Lashay, Alireza; Roozbahani, Mehdi; Fard, Masoud Aghsaei; Molaie, Saber; Mireshghi, Meysam; Zaferani, Mohamad Mehdi

    2013-04-01

    To compare pain score of single spot short duration time (20 milliseconds) panretinal photocoagulation (PRP) with conventional (100 milliseconds) PRP in diabetic retinopathy. Sixty-six eyes from 33 patients with symmetrical severe non-proliferative diabetic retinopathy (non-PDR) or proliferative diabetic retinopathy (PDR) were enrolled in this prospective randomized controlled trial. One eye of each patient was randomized to undergo conventional and the other eye to undergo short time PRP. Spot size of 200 μm was used in both laser types, and energy was adjusted to achieve moderate burn on the retina. Patients were asked to mark the level of pain felt during the PRP session for each eye on the visual analog scale (VAS) and were examined at 1 week, and at 1, 2, 4 and 6 months. Sixteen women and 17 men with mean age 58.9 ± 7.8 years were evaluated. The conventional method required a mean power of 273 ± 107 mW, whereas the short duration method needed 721 ± 406 mW (P = 0.001). An average of 1,218 ± 441 spots were delivered with the conventional method and an average of 2,125 ± 503 spots were required with the short duration method (P = 0.001). Average pain score was 7.5 ± 1.14 in conventional group and 1.75 ± 0.87 in the short duration group (P = 0.001). At 1 week, 1 month, and 4 months following PRP, the mean changes of central macular thickness (CMT) from baseline in the conventional group remained 29.2 μm (P = 0.008), 40.0 μm (P = 0.001), and 40.2 μm (P = 0.007) greater than the changes in CMT for short time group. Patient acceptance of short time single spot PRP was high, and well-tolerated in a single session by all patients. Moreover, this method is significantly less painful than but just as effective as conventional laser during 6 months of follow-up. The CMT change was more following conventional laser than short time laser.

  3. High power lasers & systems

    Chatwin, Chris; Young, Rupert; Birch, Philip

    2015-01-01

    Some laser history;\\ud Airborne Laser Testbed & Chemical Oxygen Iodine Laser (COIL);\\ud Laser modes and beam propagation;\\ud Fibre lasers and applications;\\ud US Navy Laser system – NRL 33kW fibre laser;\\ud Lockheed Martin 30kW fibre laser;\\ud Conclusions

  4. Laser Dyes

    amplification or generation of coherent light waves in the UV,. VIS, and near IR region. .... ciency in most flashlamp pumped dye lasers. It is used as reference dye .... have led to superior laser dyes with increased photostabilities. For instance ...

  5. Retrospective Study on Laser Treatment of Oral Vascular Lesions Using the "Leopard Technique": The Multiple Spot Irradiation Technique with a Single-Pulsed Wave.

    Miyazaki, Hidetaka; Ohshiro, Takafumi; Romeo, Umberto; Noguchi, Tadahide; Maruoka, Yutaka; Gaimari, Gianfranco; Tomov, Georgi; Wada, Yoshitaka; Tanaka, Kae; Ohshiro, Toshio; Asamura, Shinichi

    2018-06-01

    This study aimed to retrospectively evaluate the efficacy and safety of laser treatment of oral vascular lesions using the multiple spot irradiation technique with a single-pulsed wave. In laser therapy for vascular lesions, heat accumulation induced by excessive irradiation can cause adverse events postoperatively, including ulcer formation, resultant scarring, and severe pain. To prevent heat accumulation and side effects, we have applied a multiple pulsed spot irradiation technique, the so-called "leopard technique" (LT) to oral vascular lesions. This approach was originally proposed for laser treatment of nevi. It can avoid thermal concentration at the same spot and spare the epithelium, which promotes smooth healing. The goal of the study was to evaluate this procedure and treatment outcomes. The subjects were 46 patients with 47 oral vascular lesions treated with the LT using a Nd:YAG laser (1064 nm), including 24 thick lesions treated using a combination of the LT and intralesional photocoagulation. All treatment outcomes were satisfactory without serious complications such as deep ulcer formation, scarring, bleeding, or severe swelling. Laser therapy with the LT is a promising less-invasive treatment for oral vascular lesions.

  6. Laser for the treatment of twin to twin transfusion syndrome Laser na terapia da síndrome de transfusão feto-fetal

    Denise Araújo Lapa Pedreira

    2005-12-01

    Full Text Available PURPOSE: To report the initial experience in our country with a new technique for twin to twin transfusion syndrome (TTTS treatment, using laser to coagulate the placental vessels responsible for the twin transfusion during gestation. METHODS: Prospective study of eight cases diagnosed with TTTS evaluated in our service from january 2001 to june 2005. Through percutaneous introduction of a 2,0mm diameter fetoscope in the uterine cavity, placental surface vessels where directly visualized. Those identified as responsible for the transfusion were laser coagulated. The procedure combines ultrasonography and fetoscopy, in a so-called sonoendoscopic technique (FETENDO. RESULTS: Among the eight pregnancies evaluated, five cases were submitted to the procedure (10 fetuses. All fetuses survived for at least five weeks after surgery. A total of eight fetuses were born alive and five survived the neonatal period. In a 18 months follow-up after birth, all five are still alive and well and their mean age is now 10,6 months. The total survival rate was 50% and in three pregnancies, at least one fetus survived. CONCLUSIONS: Laser fetoscopy is actually the "gold-standard" treatment of TTTS. Nevertheless is a sophisticated technique that epends of proper training. Our service is the first in our country to offer this therapeutic technique. Our success rate is comparable with the international literature.OBJETIVO: Nosso objetivo é relatar a experiência inicial no país com uma nova técnica de tratamento para a síndrome de transfusão feto-fetal (STT, onde se utiliza o raio laser para coagulação dos vasos placentários responsáveis pela transfusão entre gêmeos durante a gravidez. MÉTODOS: Estudo prospectivo de 8 casos com diagnóstico de STT avaliados pelo nosso serviço de janeiro de 2001 a junho de 2005. Introduzindo-se um fetoscópio de 2,0 mm de diâmetro na cavidade uterina, por via percutânea, foram diretamente visualizados os vasos da superf

  7. 1.9 W yellow, CW, high-brightness light from a high efficiency semiconductor laser-based system

    Hansen, A. K.; Christensen, M.; Noordegraaf, D.; Heist, P.; Papastathopoulos, E.; Loyo-Maldonado, V.; Jensen, O. B.; Stock, M. L.; Skovgaard, P. M. W.

    2017-02-01

    Semiconductor lasers are ideal sources for efficient electrical-to-optical power conversion and for many applications where their small size and potential for low cost are required to meet market demands. Yellow lasers find use in a variety of bio-related applications, such as photocoagulation, imaging, flow cytometry, and cancer treatment. However, direct generation of yellow light from semiconductors with sufficient beam quality and power has so far eluded researchers. Meanwhile, tapered semiconductor lasers at near-infrared wavelengths have recently become able to provide neardiffraction- limited, single frequency operation with output powers up to 8 W near 1120 nm. We present a 1.9 W single frequency laser system at 562 nm, based on single pass cascaded frequency doubling of such a tapered laser diode. The laser diode is a monolithic device consisting of two sections: a ridge waveguide with a distributed Bragg reflector, and a tapered amplifier. Using single-pass cascaded frequency doubling in two periodically poled lithium niobate crystals, 1.93 W of diffraction-limited light at 562 nm is generated from 5.8 W continuous-wave infrared light. When turned on from cold, the laser system reaches full power in just 60 seconds. An advantage of using a single pass configuration, rather than an external cavity configuration, is increased stability towards external perturbations. For example, stability to fluctuating case temperature over a 30 K temperature span has been demonstrated. The combination of high stability, compactness and watt-level power range means this technology is of great interest for a wide range of biological and biomedical applications.

  8. Experimental study on the vascular thermal response to visible laser pulses.

    Li, D; Chen, B; Wu, W J; Wang, G X; He, Y L; Ying, Z X

    2015-01-01

    Port-wine stains (PWSs) are congenital vascular malformations that progressively darken and thicken with age, and laser therapy is the most effective in clinical practice. Using dorsal skin chamber (DSC), this study evaluated thermal response of blood vessel to a 595-nm pulsed dye laser (PDL) with controlled energy doses and pulse durations. Totally, 32 vessels (30∼300 μm in diameter) are selected from the dorsal skin of the mouse to match those in port-wine stain. The experimental results showed that the thermal response of the blood vessels to laser irradiation can be recognized as coagulation, constriction with diameter decrease, disappearance (complete constriction), hemorrhage, and collagen damage in the order of increasing laser radiant exposure. Blood vessels with small diameter would response poorly and survive from the laser heating because their thermal relaxation time is much shorter than the pulse duration. The optimalradiant exposure is from 10 to 12 J/cm(2) under 6 ms pulse duration without considering the epidermal light absorption. Numerical simulations were also conducted using a 1,000-μm deep Sprague-Dawley (SD) mouse skinfold. The light transportation and heat diffusion in dorsal skin were simulated with the Monte Carlo method and heat transfer equation, while the blood vessel photocoagulation was evaluated by Arrhenius-type kinetic integral. Both experimental observation and numerical simulation supported that hemorrhage is the dominant thermal response, which occurs due to preferential heating of the superior parts of large blood vessels. In clinical practice for 595 nm PDL, the consequent purpura caused by hemorrhage can be used as a treatment end point.

  9. Laser spectroscopy

    Demtröder, Wolfgang

    2008-01-01

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., frequency doubling in external cavities, reliable cw-parametric oscillators, tunable narrow-band UV sources, more sensitive detection techniques, tunable femtosecond and sub-femtosecond lasers (X-ray region and the attosecond range), control of atomic and molecular excitations, frequency combs able to synchronize independent femtosecond lasers, coherent matter waves, and still more applications in chemical analysis, medical diagnostics, and engineering.

  10. Laser spectroscopy

    Demtröder, Wolfgang

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., ultrafast lasers (atto- and femto-second lasers) and parametric oscillators, coherent matter waves, Doppler-free Fourier spectroscopy with optical frequency combs, interference spectroscopy, quantum optics, the interferometric detection of gravitational waves and still more applications in chemical analysis, medical diagnostics, and engineering.

  11. Nondamaging Retinal Laser Therapy: Rationale and Applications to the Macula.

    Lavinsky, Daniel; Wang, Jenny; Huie, Philip; Dalal, Roopa; Lee, Seung Jun; Lee, Dae Yeong; Palanker, Daniel

    2016-05-01

    Retinal photocoagulation and nondamaging laser therapy are used for treatment of macular disorders, without understanding of the response mechanism and with no rationale for dosimetry. To establish a proper titration algorithm, we measured the range of tissue response and damage threshold. We then evaluated safety and efficacy of nondamaging retinal therapy (NRT) based on this algorithm for chronic central serous chorioretinopathy (CSCR) and macular telangiectasia (MacTel). Retinal response to laser treatment below damage threshold was assessed in pigmented rabbits by expression of the heat shock protein HSP70 and glial fibrillary acidic protein (GFAP). Energy was adjusted relative to visible titration using the Endpoint Management (EpM) algorithm. In clinical studies, 21 eyes with CSCR and 10 eyes with MacTel were treated at 30% EpM energy with high spot density (0.25-diameter spacing). Visual acuity, retinal and choroidal thickness, and subretinal fluid were monitored for 1 year. At 25% EpM energy and higher, HSP70 was expressed acutely in RPE, and GFAP upregulation in Müller cells was observed at 1 month. Damage appeared starting at 40% setting. Subretinal fluid resolved completely in 81% and partially in 19% of the CSCR patients, and visual acuity improved by 12 ± 3 letters. Lacunae in the majority of MacTel patients decreased while preserving the retinal thickness, and vision improved by 10 letters. Heat shock protein expression in response to hyperthermia helps define the therapeutic window for NRT. Lack of tissue damage enables high-density treatment to boost clinical efficacy, therapy in the fovea, and retreatments to manage chronic diseases.

  12. Il laser

    Smith, William V

    1974-01-01

    Verso il 1960, il laser era ancora "una soluzione alla ricerca di un problema", ma fin dagli anni immediatamente successivi si è rivelato uno strumento insostituibile per le applicazioni più svariate.

  13. Laser Refractography

    Rinkevichyus, B.S; Raskovskaya, I.L

    2010-01-01

    This book describes the basic principles of laser refractography, a flexible new diagnostic tool for measuring optically inhomogeneous media and flows. Laser refractography is based on digital imaging and computer processing of structured laser beam refraction (SLR) in inhomogeneous transparent media. Laser refractograms provide both qualitative and quantitative measurements and can be used for the study of fast and transient processes. In this book, the theoretical basis of refractography is explored in some detail, and experimental setups are described for measurement of transparent media using either 2D (passed radiation) or 3D (scattered radiation) refractograms. Specific examples and applications are discussed, including visualization of the boundary layer near a hot or cold metallic ball in water, and observation of edge effects and microlayers in liquids and gases. As the first book to describe this new and exciting technique, this monograph has broad cross-disciplinary appeal and will be of interest t...

  14. Laser fusion

    Ashby, D.E.T.F.

    1976-01-01

    A short survey is given on laser fusion its basic concepts and problems and the present theoretical and experimental methods. The future research program of the USA in this field is outlined. (WBU) [de

  15. Laser spectroscopy

    Letokhov, V.S.

    1981-01-01

    This article describes recent progress in the application of laser atomic spectroscopy to study parameters of nuclei available in very small quantities; radioactive nuclei, rare isotopes, nuclear isomers, etc, for which study by conventional spectroscopic methods is difficult. (author)

  16. 3D Monte Carlo model of optical transport in laser-irradiated cutaneous vascular malformations

    Majaron, Boris; Milanič, Matija; Jia, Wangcun; Nelson, J. S.

    2010-11-01

    We have developed a three-dimensional Monte Carlo (MC) model of optical transport in skin and applied it to analysis of port wine stain treatment with sequential laser irradiation and intermittent cryogen spray cooling. Our MC model extends the approaches of the popular multi-layer model by Wang et al.1 to three dimensions, thus allowing treatment of skin inclusions with more complex geometries and arbitrary irradiation patterns. To overcome the obvious drawbacks of either "escape" or "mirror" boundary conditions at the lateral boundaries of the finely discretized volume of interest (VOI), photons exiting the VOI are propagated in laterally infinite tissue layers with appropriate optical properties, until they loose all their energy, escape into the air, or return to the VOI, but the energy deposition outside of the VOI is not computed and recorded. After discussing the selection of tissue parameters, we apply the model to analysis of blood photocoagulation and collateral thermal damage in treatment of port wine stain (PWS) lesions with sequential laser irradiation and intermittent cryogen spray cooling.

  17. Laser fusion

    Key, M.H.; Oxford Univ.

    1990-04-01

    The use of lasers to drive implosions for the purpose of inertially confined fusion is an area of intense activity where progress compares favourably with that made in magnetic fusion and there are significant prospects for future development. In this brief review the basic concept is summarised and the current status is outlined both in the area of laser technology and in the most recent results from implosion experiments. Prospects for the future are also considered. (author)

  18. Laser Resurfacing

    Janik, Joseph P.; Markus, Jodi L.; Al-Dujaili, Zeena; Markus, Ramsey F.

    2007-01-01

    In a society desiring images of beauty and youthfulness, the world of cutaneous surgery offers the gifts of facial rejuvenation for those determined to combat the signs of aging. With the development of novel laser and plasma technology, pigmentary changes, scarring, and wrinkles can be conquered providing smoother, healthier, younger-looking skin. This review highlights five of the most popular resurfacing technologies in practice today including the carbon dioxide (CO2) laser, the erbium:yt...

  19. Green lasers

    Jensen, Ole Bjarlin

    2010-01-01

    Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range......Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range...

  20. Different lasers and techniques for proliferative diabetic retinopathy.

    Moutray, Tanya; Evans, Jennifer R; Lois, Noemi; Armstrong, David J; Peto, Tunde; Azuara-Blanco, Augusto

    2018-03-15

    Diabetic retinopathy (DR) is a chronic progressive disease of the retinal microvasculature associated with prolonged hyperglycaemia. Proliferative DR (PDR) is a sight-threatening complication of DR and is characterised by the development of abnormal new vessels in the retina, optic nerve head or anterior segment of the eye. Argon laser photocoagulation has been the gold standard for the treatment of PDR for many years, using regimens evaluated by the Early Treatment of Diabetic Retinopathy Study (ETDRS). Over the years, there have been modifications of the technique and introduction of new laser technologies. To assess the effects of different types of laser, other than argon laser, and different laser protocols, other than those established by the ETDRS, for the treatment of PDR. We compared different wavelengths; power and pulse duration; pattern, number and location of burns versus standard argon laser undertaken as specified by the ETDRS. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 5); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and the ICTRP. The date of the search was 8 June 2017. We included randomised controlled trials (RCTs) of pan-retinal photocoagulation (PRP) using standard argon laser for treatment of PDR compared with any other laser modality. We excluded studies of lasers that are not in common use, such as the xenon arc, ruby or Krypton laser. We followed Cochrane guidelines and graded the certainty of evidence using the GRADE approach. We identified 11 studies from Europe (6), the USA (2), the Middle East (1) and Asia (2). Five studies compared different types of laser to argon: Nd:YAG (2 studies) or diode (3 studies). Other studies compared modifications to the standard argon laser PRP technique. The studies were poorly reported and we judged all to be at high risk of bias in at least one domain. The sample size

  1. Laser material processing

    Steen, William

    2010-01-01

    This text moves from the basics of laser physics to detailed treatments of all major materials processing techniques for which lasers are now essential. New chapters cover laser physics, drilling, micro- and nanomanufacturing and biomedical laser processing.

  2. Laser therapy for cancer

    ... this page: //medlineplus.gov/ency/patientinstructions/000905.htm Laser therapy for cancer To use the sharing features ... Lasers are also used on the skin. How Laser Therapy is Used Laser therapy can be used ...

  3. Lasers in Cancer Treatment

    ... the advantages of laser therapy? What are the disadvantages of laser therapy? What does the future hold ... therapy is appropriate for them. What are the disadvantages of laser therapy? Laser therapy also has several ...

  4. Practical laser safety

    Winburn, D.C.

    1985-01-01

    This book includes discussions of the following topics: characteristics of lasers; eye components; skin damage thresholds; classification of lasers by ANSI Z136.1; selecting laser-protective eyewear; hazards associated with lasers; and, an index

  5. Intravenous injection of artificial red cells and subsequent dye laser irradiation causes deep vessel impairment in an animal model of port-wine stain.

    Rikihisa, Naoaki; Tominaga, Mai; Watanabe, Shoji; Mitsukawa, Nobuyuki; Saito, Yoshiaki; Sakai, Hiromi

    2018-03-15

    Our previous study proposed using artificial blood cells (hemoglobin vesicles, Hb-Vs) as photosensitizers in dye laser treatment for port-wine stains (PWSs). Dye laser photons are absorbed by red blood cells (RBCs) and hemoglobin (Hb) mixture, which potentially produce more heat and photocoagulation and effectively destroy endothelial cells. Hb-Vs combination therapy will improve clinical outcomes of dye laser treatment for PWSs because very small vessels do not contain sufficient RBCs and they are poor absorbers/heaters of lasers. In the present study, we analyzed the relationship between vessel depth from the skin surface and vessel distraction through dye laser irradiation following intravenous Hb-Vs injection using a chicken wattle model. Hb-Vs were administered and chicken wattles underwent high-energy irradiation at energy higher than in the previous experiments. Hb-Vs location in the vessel lumen was identified to explain its photosensitizer effect using human Hb immunostaining of the irradiated wattles. Laser irradiation with Hb-Vs can effectively destroy deep vessels in animal models. Hb-Vs tend to flow in the marginal zone of both small and large vessels. Increasing laser power combined with Hb-Vs injection contributed for deep vessel impairment because of the synergetic effect of both methods. Newly added Hb tended to flow near the target endothelial cells of the laser treatment. In Hb-Vs and RBC mixture, heat transfer to endothelial cells from absorbers/heater may increase. Hb-Vs function as photosensitizers to destroy deep vessels within a restricted distance that the photon can reach.

  6. Outcome of solid-state 532 nm green laser in high-risk retinopathy of prematurity at a tertiary care centre in India.

    Chhabra, Kanika; Kaur, Prempal; Singh, Karamjit; Aggarwal, Anand; Chalia, Dharamvir

    2018-02-01

    The purpose of this study was to analyse the outcome of solid-state green laser in high-risk retinopathy of prematurity (ROP) at a tertiary centre in India. Fifty-nine eyes of 30 infants with high-risk ROP were recruited in this prospective, interventional study. High-risk ROP included prethreshold type 1 ROP and APROP. Laser photocoagulation was performed with 532 nm solid-state green laser (Novus Spectra, Lumenis, GmbH, Germany). Of the 30 infants, 18 were males (60%) and 12 were females (40%). The mean birth weight was 1102.83 ± 196.27 g. The mean gestational age was 29.5 ± 1.47 weeks. Zone 1 disease was present in 10 eyes (16.95%) and zone 2 disease in 49 (83.05%) eyes. Out of 57 eyes with prethreshold type 1 ROP, 39 eyes (68.42%) had stage 2 and 18 eyes (31.58%) had stage 3. The postconceptional age at the time of treatment was 36.03 ± 2.32 weeks. The infants received mean 2710.24 ± 747.97 laser spots. Fifty (84.8%) eyes underwent laser in a single sitting and 9 eyes (15.2%) required 2 laser sittings. Mean time for regression of ROP was 5.8 ± 3.8 weeks (range 3-11 weeks). Total ROP regression was seen in 55 eyes (93.22%). Despite laser treatment, 4 (6.78%) eyes of three infants had unfavourable outcome. One infant developed intra-procedural bradycardia. Vitreous haemorrhage was seen in five eyes (8.4%). Solid-state 532 nm green laser is a safe and effective treatment for high-risk retinopathy of prematurity.

  7. Laser acceleration

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  8. Laser acceleration

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-01-01

    The fundamental idea of LaserWakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wake fields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ∼ c and ultra fastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nano materials is also emerging.

  9. Non-damaging laser therapy of the macula: Titration algorithm and tissue response

    Palanker, Daniel; Lavinsky, Daniel; Dalal, Roopa; Huie, Philip

    2014-02-01

    Retinal photocoagulation typically results in permanent scarring and scotomata, which limit its applicability to the macula, preclude treatments in the fovea, and restrict the retreatments. Non-damaging approaches to laser therapy have been tested in the past, but the lack of reliable titration and slow treatment paradigms limited their clinical use. We developed and tested a titration algorithm for sub-visible and non-damaging treatments of the retina with pulses sufficiently short to be used with pattern laser scanning. The algorithm based on Arrhenius model of tissue damage optimizes the power and duration for every energy level, relative to the threshold of lesion visibility established during titration (and defined as 100%). Experiments with pigmented rabbits established that lesions in the 50-75% energy range were invisible ophthalmoscopically, but detectable with Fluorescein Angiography and OCT, while at 30% energy there was only very minor damage to the RPE, which recovered within a few days. Patients with Diabetic Macular Edema (DME) and Central Serous Retinopathy (CSR) have been treated over the edematous areas at 30% energy, using 200μm spots with 0.25 diameter spacing. No signs of laser damage have been detected with any imaging modality. In CSR patients, subretinal fluid resolved within 45 days. In DME patients the edema decreased by approximately 150μm over 60 days. After 3-4 months some patients presented with recurrence of edema, and they responded well to retreatment with the same parameters, without any clinically visible damage. This pilot data indicates a possibility of effective and repeatable macular laser therapy below the tissue damage threshold.

  10. Laser Heterodyning

    Protopopov, Vladimir V

    2009-01-01

    Laser heterodyning is now a widespread optical technique, based on interference of two waves with slightly different frequencies within the sensitive area of a photo-detector. Its unique feature – preserving phase information about optical wave in the electrical signal of the photo-detector – finds numerous applications in various domains of applied optics and optoelectronics: in spectroscopy, polarimetry, radiometry, laser radars and Lidars, microscopy and other areas. The reader may be surprised by a variety of disciplines that this book covers and satisfied by detailed explanation of the phenomena. Very well illustrated, this book will be helpful for researches, postgraduates and students, working in applied optics.

  11. Intravitreal itraconazole inhibits laser-induced choroidal neovascularization in rats.

    Jeong Hun Bae

    Full Text Available Choroidal neovascularization (CNV is a major cause of severe visual loss in patients with age-related macular degeneration (AMD. Recently, itraconazole has shown potent and dose-dependent inhibition of tumor-associated angiogenesis. We evaluated the anti-angiogenic effect of itraconazole in a rat model of laser-induced CNV. After laser photocoagulation in each eye to cause CNV, right eyes were administered intravitreal injections of itraconazole; left eyes received balanced salt solution (BSS as controls. On day 14 after laser induction, fluorescein angiography (FA was used to assess abnormal vascular leakage. Flattened retinal pigment epithelium (RPE-choroid tissue complex was stained with Alexa Fluor 594-conjugated isolectin B4 to measure the CNV area and volume. Vascular endothelial growth factor receptor 2 (VEGFR2 mRNA and protein expression was determined 1, 4, 7, and 14 days after intravitreal injection by quantitative RT-PCR or Western blot. VEGF levels were analyzed by enzyme-linked immunosorbent assay (ELISA. Intravitreal itraconazole significantly reduced leakage from CNV as assessed by FA and CNV area and volume on flat mounts compared with intravitreal BSS (p = 0.002 for CNV leakage, p<0.001 for CNV area and volume. Quantitative RT-PCR showed significantly lower expression of VEGFR2 mRNA in the RPE-choroid complexes of itraconazole-injected eyes than those of BSS-injected eyes on days 7 and 14 (p = 0.003 and p = 0.006. Western blots indicated that VEGFR2 was downregulated after itraconazole treatment. ELISA showed a significant difference in VEGF level between itraconazole-injected and BSS-injected eyes on days 7 and 14 (p = 0.04 and p = 0.001. Our study demonstrated that intravitreal itraconazole significantly inhibited the development of laser-induced CNV in rats. Itraconazole had anti-angiogenic activity along with the reduction of VEGFR2 and VEGF levels. Itraconazole may prove beneficial for treating CNV as an alternative or

  12. Laser polarimetry

    Goldstein, D.H.

    1989-01-01

    Polarimetry, or transmission ellipsometry, is an important experimental technique for the determination of polarization properties of bulk materials. In this technique, source radiation of known polarization is passed through bulk samples to determine, for example, natural or induced birefringence and dichroism. The laser is a particularly appropriate source for this technique because of its monochromaticity, collimation, and radiant intensity. Lasers of many different wavelengths in different spectral regions are now available. Laser polarimetry can be done in any of these wavelength regions where polarizing elements are available. In this paper, polarimetry is reviewed with respect to applications, sources used, and polarization state generator and analyzer configurations. Scattering ellipsometry is also discussed insofar as the forward scattering measurement is related to polarimetry. The authors then describe an infrared laser polarimeter which we have designed and constructed. This instrument can operate over large wavelength regions with only a change in source. Polarization elements of the polarimeter are in a dual rotating retarder configuration. Computer controlled rotary stages and computer monitored detectors automate the data collection. The Mueller formulation is used to process the polarization information. Issues and recent progress with this instrument are discussed

  13. excimer laser

    2014-01-07

    Jan 7, 2014 ... is necessary to deposit one order higher input electric power into gas medium than ... cross-sectional view of the laser system is shown in figure 2A. The system mainly consists ... Considering the simplicity and reliability of the.

  14. Laser device

    2013-01-01

    The present invention provides a light source for light circuits on a silicon platform. A vertical laser cavity is formed by a gain region arranged between a first mirror structure and a second mirror structure, both acting as mirrors, by forming a grating region including an active material...

  15. Nanowire Lasers

    Couteau C.

    2015-05-01

    Full Text Available We review principles and trends in the use of semiconductor nanowires as gain media for stimulated emission and lasing. Semiconductor nanowires have recently been widely studied for use in integrated optoelectronic devices, such as light-emitting diodes (LEDs, solar cells, and transistors. Intensive research has also been conducted in the use of nanowires for subwavelength laser systems that take advantage of their quasione- dimensional (1D nature, flexibility in material choice and combination, and intrinsic optoelectronic properties. First, we provide an overview on using quasi-1D nanowire systems to realize subwavelength lasers with efficient, directional, and low-threshold emission. We then describe the state of the art for nanowire lasers in terms of materials, geometry, andwavelength tunability.Next,we present the basics of lasing in semiconductor nanowires, define the key parameters for stimulated emission, and introduce the properties of nanowires. We then review advanced nanowire laser designs from the literature. Finally, we present interesting perspectives for low-threshold nanoscale light sources and optical interconnects. We intend to illustrate the potential of nanolasers inmany applications, such as nanophotonic devices that integrate electronics and photonics for next-generation optoelectronic devices. For instance, these building blocks for nanoscale photonics can be used for data storage and biomedical applications when coupled to on-chip characterization tools. These nanoscale monochromatic laser light sources promise breakthroughs in nanophotonics, as they can operate at room temperature, can potentially be electrically driven, and can yield a better understanding of intrinsic nanomaterial properties and surface-state effects in lowdimensional semiconductor systems.

  16. Excimer Laser Technology

    Basting, Dirk

    2005-01-01

    This comprehensive survey on Excimer Lasers investigates the current range of the technology, applications and devices of this commonly used laser source, as well as the future of new technologies, such as F2 laser technology. Additional chapters on optics, devices and laser systems complete this compact handbook. A must read for laser technology students, process application researchers, engineers or anyone interested in excimer laser technology. An effective and understandable introduction to the current and future status of excimer laser technology.

  17. Laser ion sources

    Bykovskij, Yu

    1979-02-01

    The characteristics a laser source of multiply-ionized ions are described with regard to the interaction of laser radiation and matter, ion energy spectrum, angular ion distribution. The amount of multiple-ionization ions is evaluated. Out of laser source applications a laser injector of multiple-ionization ions and nuclei, laser mass spectrometry, laser X-ray microradiography, and a laser neutron generators are described.

  18. Dermatological laser treatment

    Moerk, N.J.; Austad, J.; Helland, S.; Thune, P.; Volden, G.; Falk, E.

    1991-01-01

    The article reviews the different lasers used in dermatology. Special emphasis is placed on the treatment of naevus flammeus (''portwine stain'') where lasers are the treatment of choice. Argon laser and pulsed dye laser are the main lasers used in vascular skin diseases, and the article focuses on these two types. Copper-vapour laser, neodymium-YAG laser and CO 2 laser are also presented. Information is provided about the availability of laser technology in the different health regions in Norway. 5 refs., 2 figs

  19. Grid laser with modified pro re nata injection of bevacizumab and ranibizumab in macular edema due to branch retinal vein occlusion: MARVEL report no 2.

    Narayanan, Raja; Panchal, Bhavik; Stewart, Michael W; Das, Taraprasad; Chhablani, Jay; Jalali, Subhadra; Hasnat Ali, Mohd

    2016-01-01

    The purpose of this study was to prospectively study the efficacy of grid laser combined with intravitreal bevacizumab or ranibizumab in eyes with macular edema due to branch retinal vein occlusion. Treatment-naïve eyes were enrolled to receive injections of ranibizumab or bevacizumab. During the first 6 months, patients were evaluated monthly and injected if the best-corrected visual acuity changed by five or more letters or fluid was noted on spectral domain optical coherence tomography (OCT); during the next 6 months, patients were evaluated bimonthly and injected only if the best-corrected visual acuity decreased by five or more letters with the associated fluid. Grid laser photocoagulation was performed if there was fluid on OCT and was repeated if patients were eligible after a minimum interval of 3 months. The mean numbers of ranibizumab and bevacizumab injections were, respectively, 3.2±1.5 and 3.0±1.4 in the first 6 months and 0.3±0.6 and 0.3±0.6 in the last 6 months. Moreover, 55/75 (73.33%) participants did not receive any injections in the last 6 months. The mean reductions in central retinal thickness at 12 months were 165.67 μm (P<0.001; 95% confidence interval -221.50 to -135.0) in the ranibizumab group and 184.78 μm (P<0.001; 95% confidence interval -246.49 to -140.0) in the bevacizumab group (P=0.079). More patients in the bevacizumab group compared to those in the ranibizumab group required rescue laser at 12 months (20 vs eleven; P=0.06). Bimonthly evaluations after month 6 with very few pro re nata injections were effective in maintaining visual gains achieved during the first 6 months. Grid laser photocoagulation is effective in maintaining the vision even in the presence of fluid on OCT, although it's required more often in patients treated with bevacizumab.

  20. Grid laser with modified pro re nata injection of bevacizumab and ranibizumab in macular edema due to branch retinal vein occlusion: MARVEL report no 2

    Narayanan, Raja; Panchal, Bhavik; Stewart, Michael W; Das, Taraprasad; Chhablani, Jay; Jalali, Subhadra; Hasnat Ali, Mohd

    2016-01-01

    Purpose The purpose of this study was to prospectively study the efficacy of grid laser combined with intravitreal bevacizumab or ranibizumab in eyes with macular edema due to branch retinal vein occlusion. Patients and methods Treatment-naïve eyes were enrolled to receive injections of ranibizumab or bevacizumab. During the first 6 months, patients were evaluated monthly and injected if the best-corrected visual acuity changed by five or more letters or fluid was noted on spectral domain optical coherence tomography (OCT); during the next 6 months, patients were evaluated bimonthly and injected only if the best-corrected visual acuity decreased by five or more letters with the associated fluid. Grid laser photocoagulation was performed if there was fluid on OCT and was repeated if patients were eligible after a minimum interval of 3 months. Results The mean numbers of ranibizumab and bevacizumab injections were, respectively, 3.2±1.5 and 3.0±1.4 in the first 6 months and 0.3±0.6 and 0.3±0.6 in the last 6 months. Moreover, 55/75 (73.33%) participants did not receive any injections in the last 6 months. The mean reductions in central retinal thickness at 12 months were 165.67 μm (P<0.001; 95% confidence interval −221.50 to −135.0) in the ranibizumab group and 184.78 μm (P<0.001; 95% confidence interval −246.49 to −140.0) in the bevacizumab group (P=0.079). More patients in the bevacizumab group compared to those in the ranibizumab group required rescue laser at 12 months (20 vs eleven; P=0.06). Conclusion Bimonthly evaluations after month 6 with very few pro re nata injections were effective in maintaining visual gains achieved during the first 6 months. Grid laser photocoagulation is effective in maintaining the vision even in the presence of fluid on OCT, although it’s required more often in patients treated with bevacizumab. PMID:27330272

  1. Dynamic changes of photorecrptor layer in eyes with acute central serous chorioretinopathy after laser treatment by fourier-domain optical coherence tomography

    Li-Qin Zhou

    2014-10-01

    Full Text Available AIM: To dynamically observe the feeling change of the photorecrptor layer in the eyes with acute central serous chorioretinopathy(CSCRkrypton laser treatment by fourier-domain optical coherence tomography(FD-OCT, and to study their correlation with the chang of vision.METHODS: This is a retrospective case series study. The clinical diagnosis of 52 patients with monocular initial onset of central serous chorioretinopathy, krypton laser photocoagulation before treatment, after 1, 2, 4, 6, 8wk, 6mo, FD-OCT were performed to observe the morphological changes characteristic of photoreceptor layer and changes in vision. RESULTS: After 1wk treatment, all cases were improved; 2wk, 6 cases were cured; 4wk, 38 cases were cured; 6wk, 41 cases were cured; 8wk, 45 cases were cured, the OCT showed macular retinal neuroepithelial layer(RNLfrom fully absorbed; 6mo with the same 8wk. Before and after treatment in patients with best corrected visual acuity and from the height difference between the macular region of RNL was statistically significant(PPPCONCLUSION: FD-OCT can dynamicaly observed acute central serous chorioretinopathy krypton laser treatment of photoreceptor ultrastruture changes. Photoreceptor layer of complete and incomplete best corrected visual acuity difference was statistically significant(P<0.01.

  2. CO2-laser fusion

    Stark, E.E. Jr.

    1978-01-01

    The basic concept of laser fusion is described, with a set of requirements on the laser system. Systems and applications concepts are presented and discussed. The CO 2 laser's characteristics and advantages for laser fusion are described. Finally, technological issues in the development of CO 2 laser systems for fusion applications are discussed

  3. Project LASER

    1990-01-01

    NASA formally launched Project LASER (Learning About Science, Engineering and Research) in March 1990, a program designed to help teachers improve science and mathematics education and to provide 'hands on' experiences. It featured the first LASER Mobile Teacher Resource Center (MTRC), is designed to reach educators all over the nation. NASA hopes to operate several MTRCs with funds provided by private industry. The mobile unit is a 22-ton tractor-trailer stocked with NASA educational publications and outfitted with six work stations. Each work station, which can accommodate two teachers at a time, has a computer providing access to NASA Spacelink. Each also has video recorders and photocopy/photographic equipment for the teacher's use. MTRC is only one of the five major elements within LASER. The others are: a Space Technology Course, to promote integration of space science studies with traditional courses; the Volunteer Databank, in which NASA employees are encouraged to volunteer as tutors, instructors, etc; Mobile Discovery Laboratories that will carry simple laboratory equipment and computers to provide hands-on activities for students and demonstrations of classroom activities for teachers; and the Public Library Science Program which will present library based science and math programs.

  4. Laser Research Lab

    Federal Laboratory Consortium — The Laser Research lab is thecenter for the development of new laser sources, nonlinear optical materials, frequency conversion processes and laser-based sensors for...

  5. Laser therapy (image)

    A laser is used for many medical purposes. Because the laser beam is so small and precise, it enables ... without injuring surrounding tissue. Some uses of the laser are retinal surgery, excision of lesions, and cauterization ...

  6. Laser fusion: an overview

    Boyer, K.

    1975-01-01

    The laser fusion concept is described along with developments in neodymium and carbon dioxide lasers. Fuel design and fabrication are reviewed. Some spin-offs of the laser fusion program are discussed. (U.S.)

  7. Laser power supply

    Bernstein, D.

    1975-01-01

    The laser power supply includes a regulator which has a high voltage control loop based on a linear approximation of a laser tube negative resistance characteristic. The regulator has independent control loops for laser current and power supply high voltage

  8. Bleaching Dengan Teknologi Laser

    Eliwaty

    2008-01-01

    Penulisan tentang bleaching dengan laser dimaksudkan untuk menambah wawasan serta pengetahuan dari pembaca di bidang kedokteran gigi. Macam-macam laser yang dipergunakan dalam bleaching yaitu argon, CO2 serta dioda laser. Contoh merek produk laser yaitu Blulaze, Dentcure untuk argonlaser, Novapulse untuk C02 serta Opus 5 untuk dioda laser. Laser bleaching hasilnya dapat dicapai dalam satu kunjungan saja, cepat, efisien namun biayanya relatif mahal, dapat menimbulkan burn, sensitivitas se...

  9. Comparison of structural outcome between intravitreal bevacizumab and laser treatment for type 1 retinopathy of prematurity after long-term follow-up

    Yen-Yi Chen; Yun-Ju Chen; Yung-Ray Hsu; Fang-Ting Chen; Jia-Kang Wang

    2016-01-01

    Background:To compare the structural outcome of intravitreal bevacizumab (IVB) and laser treatment for type 1 retinopathy of prematurity (ROP). Methods: This is a retrospective comparative study. From December 2002 to April 2009, patients with type 1 ROP according to criteria of Early Treatment of Retinopathy of Prematurity (ETROP) study were treated by peripheral retinal diode laser photocoagulation in nearly confluent pattern. From May 2009 to January 2015, we performed IVB for patients with type 1 ROP. The patients were closely followed until disappearance of retinal neovascularization in the laser group and regression of avascular zone in the bevacizumab group. The demographical data, postmenstrual age (PMA) for treatment, and fundus ifndings were recorded by chart review. The difference between laser and bevacizumab groups was compared by Studentt-test and Fisher exact test. Results: We collected 43 patients (86 eyes) with type 1 ROP, including 30 male and 13 female infants. Their mean gestation age and birth body weight (BBW) were 27.5 weeks and 1,034 gm. Zone I and zone II disease were found in 8 and 35 patients. The mean PMA for treatment was 37.3 weeks. The mean follow-up period was 54.4 months. Laser treatment was administered in 26 patients, and bevacizumab injection for 17 infants. Single session of laser was performed in all patients of laser group without recurrence of retinal neovascularization. Complete regression of ROP was found in 15 infants of bevacizumab group following the ifrst IVB. Four eyes in two patients (2/17, 11.7%) had recurrence of ROP and received additional injections and adjuvant laser treatment. There was no unfavorable anatomical results such as retinal detachment or macular ectopia or complications such as cataract or endophthalmitis in either bevacizumab or laser management. Conclusions: Laser therapy and IVB were both effective treatments for type 1 ROP to cause favorable anatomical outcomes. Single session of laser ablation

  10. Laser safety at high profile laser facilities

    Barat, K.

    2010-01-01

    Complete text of publication follows. Laser safety has been an active concern of laser users since the invention of the laser. Formal standards were developed in the early 1970's and still continue to be developed and refined. The goal of these standards is to give users guidance on the use of laser and consistent safety guidance and requirements for laser manufacturers. Laser safety in the typical research setting (government laboratory or university) is the greatest challenge to the laser user and laser safety officer. This is due to two factors. First, the very nature of research can put the user at risk; consider active manipulation of laser optics and beam paths, and user work with energized systems. Second, a laser safety culture that seems to accept laser injuries as part of the graduate student educational process. The fact is, laser safety at research settings, laboratories and universities still has long way to go. Major laser facilities have taken a more rigid and serious view of laser safety, its controls and procedures. Part of the rationale for this is that these facilities draw users from all around the world presenting the facility with a work force of users coming from a wide mix of laser safety cultures. Another factor is funding sources do not like bad publicity which can come from laser accidents and a poor safety record. The fact is that injuries, equipment damage and lost staff time slow down progress. Hence high profile/large laser projects need to adapt a higher safety regimen both from an engineering and administrative point of view. This presentation will discuss all these points and present examples. Acknowledgement. This work has been supported by the University of California, Director, Office of Science.

  11. Semiconductor Laser Measurements Laboratory

    Federal Laboratory Consortium — The Semiconductor Laser Measurements Laboratory is equipped to investigate and characterize the lasing properties of semiconductor diode lasers. Lasing features such...

  12. Laser Protection TIL

    Federal Laboratory Consortium — The Laser Protection TIL conducts research and analysis of laser protection materials along with integration schemes. The lab's objectives are to limit energy coming...

  13. Laser Photochemistry.

    1981-07-01

    inverted by the first, i.e., at the moment of time t = T, such that i = (2n+)lT, where 0 is the Rabi frequency (Oraevski et al., 1976). . classical... anisotropic molecule present. CW HeNe, Ar+ and Kr+ lasers are used, and the filter method is necessary because of time-scales lo8 - 10ll Hz. Some general...e.g., truncated harmonic oscillator, square well, spherically symmetric Morse or Lennard-Jones, anisotropic (angle-dependent) Morse or Lennard-Jones

  14. 多波长激光治疗DR合并视网膜中央静脉阻塞%Efficacy observation on multiple wave length laser for diabetic retinopathy and central retinal vein occlusion

    田涛; 刘茹; 彭婧利; 谢丽莲; 邝国平

    2014-01-01

    目的:观察多波长激光治疗糖尿病视网膜病变( diabetic retinopathy,DR)合并视网膜中央静脉阻塞( central retinal vein occlusion, CRVO)的疗效。  方法:选取DR合并CRVO患者95例100眼,采用多波长激光进行光凝治疗。其中黄斑区以氪黄激光治疗为主,包括局部光凝和格栅光凝,周边光凝以氪绿或氪红激光进行治疗。手术前后均进行视力、眼底、荧光素眼底血管造影检查。术后随访12~48 wk。观察比较两组光凝前后视力及黄斑水肿变化,并做统计学分析。  结果:在黄斑格栅光凝组,有效率为61.2%,在黄斑局部光凝组,有效率为86.3%,后者总有效率高于前者,有统计学差异(P  结论:多波长激光治疗DR合并CRVO患者的黄斑水肿安全、有效。%AlM:To observe the efficacy of the multiple wave length laser in treating diabetic retinopathy combined with central retinal vein occlusion. METHODS:Totally 95 cases ( 100 eyes ) with diabetic retinopathy combined with central retinal vein occlusion were treated by multiple wave length laser. Krypton yellow laser was used for macular edema in focal photocoagulation and diffuse photocoagulation. For peripheral retina, krypton green or krypton red laser were used. Visual acuity, slit - lamp biomicroscopy, ophthalmoscopy and fundus fluorescein angiography were performed preoperatively and postoperatively. The patients were followed up for 12 to 48wk. ln this study, change in visual acuity and macular edema were observed in both groups, and statistical analysis was performed. RESULTS: The effective rate was 61. 2% in diffuse macular edema group and 86. 3% in focal macular edema group. The general effective rate of later was higher than the former, while the treatment effect had significant statistical difference (P CONCLUSlON:Multiple wave length laser is an effective and safe way to treat diabetic macular edema of diabetic retinopathy combined with central retinal vein

  15. Laser Propulsion - Quo Vadis

    Bohn, Willy L.

    2008-01-01

    First, an introductory overview of the different types of laser propulsion techniques will be given and illustrated by some historical examples. Second, laser devices available for basic experiments will be reviewed ranging from low power lasers sources to inertial confinement laser facilities. Subsequently, a status of work will show the impasse in which the laser propulsion community is currently engaged. Revisiting the basic relations leads to new avenues in ablative and direct laser propulsion for ground based and space based applications. Hereby, special attention will be devoted to the impact of emerging ultra-short pulse lasers on the coupling coefficient and specific impulse. In particular, laser sources and laser propulsion techniques will be tested in microgravity environment. A novel approach to debris removal will be discussed with respect to the Satellite Laser Ranging (SRL) facilities. Finally, some non technical issues will be raised aimed at the future prospects of laser propulsion in the international community

  16. Laser safety and practice

    Low, K.S.

    1995-01-01

    Lasers are finding increasing routine applications in many areas of science, medicine and industry. Though laser radiation is non-ionizing in nature, the usage of high power lasers requires specific safety procedures. This paper briefly outlines the properties of laser beams and various safety procedures necessary in their handling and usage. (author)

  17. Diode lasers and arrays

    Streifer, W.

    1988-01-01

    This paper discusses the principles of operation of III-V semiconductor diode lasers, the use of distributed feedback, and high power laser arrays. The semiconductor laser is a robust, miniature, versatile device, which directly converts electricity to light with very high efficiency. Applications to pumping solid-state lasers and to fiber optic and point-to-point communications are reviewed

  18. Laser cladding with powder

    Schneider, M.F.; Schneider, Marcel Fredrik

    1998-01-01

    This thesis is directed to laser cladding with powder and a CO2 laser as heat source. The laser beam intensity profile turned out to be an important pa6 Summary rameter in laser cladding. A numerical model was developed that allows the prediction of the surface temperature distribution that is

  19. Semiconductor laser shearing interferometer

    Ming Hai; Li Ming; Chen Nong; Xie Jiaping

    1988-03-01

    The application of semiconductor laser on grating shearing interferometry is studied experimentally in the present paper. The method measuring the coherence of semiconductor laser beam by ion etching double frequency grating is proposed. The experimental result of lens aberration with semiconductor laser shearing interferometer is given. Talbot shearing interferometry of semiconductor laser is also described. (author). 2 refs, 9 figs

  20. Visible Solid State Lasers

    Hikmet, R.A.M.

    2007-01-01

    Diode lasers can be found in various applications most notably in optical communication and optical storage. Visible lasers were until recently were all based on IR diode lasers. Using GaN, directly blue and violet emitting lasers have also been introduced to the market mainly in the area of optical

  1. Laser Microdissection.

    Frost, Andra R; Eltoum, Isam-Eldin; Siegal, Gene P; Emmert-Buck, Michael R; Tangrea, Michael A

    2015-10-01

    Laser microdissection (LM) offers a relatively rapid and precise method of isolating and removing specified cells from complex tissues for subsequent analysis of their RNA, DNA, protein or metabolite content, thereby allowing assessment of the role of different cell types in the normal physiological or disease processes being studied. In this unit, protocols for the preparation of mammalian frozen tissues, fixed tissues, and cytologic specimens for LM, including tissue freezing, tissue processing and paraffin embedding, histologic sectioning, cell processing, hematoxylin and eosin staining, immunohistochemistry, and image-guided cell targeting are presented. Also provided are recipes for generating lysis buffers for the recovery of nucleic acids and proteins. The Commentary section addresses the types of specimens that can be utilized for LM and approaches to staining of specimens for cell visualization. Emphasis is placed on the preparation of tissue or cytologic specimens as this is critical to effective LM. Copyright © 2015 John Wiley & Sons, Inc.

  2. Laser EXAFS

    Mallozzi, P.J.; Epstein, H.M.; Schwenzel, R.E.; Campbell, B.E.

    1983-01-01

    Apparatus for obtaining EXAFS data of a material, comprising means for directing radiant energy from a laser onto a target in such manner as to produce X-rays at the target of a selected spectrum and intensity, suitable for obtaining the EXAFS spectrum of the material, means for directing X-rays from the target onto spectral dispersive means so located as to direct the spectrally resolved X-rays therefrom onto recording means, and means for positioning a sample of material in the optical path of the X-rays, the recording means providing a reference spectrum of X-rays not affected by the sample and absorption spectrum of X-rays modified by transmission through the sample

  3. Multibeam Fibre Laser Cutting

    Olsen, Flemming Ove

    The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre......-laser cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single...

  4. Multibeam fiber laser cutting

    Olsen, Flemming Ove; Hansen, Klaus Schütt; Nielsen, Jakob Skov

    2009-01-01

    The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating Cutting laser, the CO2 laser. However, quality problems in fiber......-laser cutting have until now limited its application to metal cutting. In this paper the first results of proof-of-principle Studies applying a new approach (patent pending) for laser cutting with high brightness and short wavelength lasers will be presented. In the approach, multibeam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W...

  5. History and principle of lasers

    Townes, Ch.H.; Schwob, C.; Julien, J.; Forget, S.; Robert-Philip, I.; Balcou, Ph.

    2010-01-01

    In the first article C.H. Townes, the inventor of the maser, describes the work and ideas that led to the invention of the laser. The second article explains how a laser operate and the third article reviews the main different types of laser: solid lasers, gas lasers, diode lasers and dye lasers

  6. Technological laser application

    Shia, D.O.; Kollen, R.; Rods, U.

    1980-01-01

    Problems of the technological applications of lasers are stated in the popular form. Main requirements to a technological laser as well as problems arising in designing any system using lasers have been considered. Areas of the laser applications are described generally: laser treatment of materials, thermal treatment, welding, broach and drilling of holes, scribing, microtreatment and adjustment of resistors, material cutting, investigations into controlled thermonuclear fussion

  7. Laser ablation principles and applications

    1994-01-01

    Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.

  8. Prevalence and outcomes of laser treatment of aggressive posterior retinopathy of prematurity.

    Gunn, David J; Cartwright, David W; Gole, Glen A

    2014-07-01

    To describe outcomes in a cohort of extremely premature infants treated for aggressive posterior retinopathy of prematurity by diode laser panretinal photocoagulation. Retrospective study. Fifteen eyes in eight infants. A review was carried out on infants between 23 and 25.6 weeks gestational age admitted to The Royal Brisbane and Women's Hospital neonatal intensive care unit between 1992 and 2009. Success of treatment, visual and refractive outcomes. Five hundred fifty-four infants were admitted to neonatal intensive care unit, 373 survived till screening, and 304 had retinopathy of prematurity. Sixty-six infants required treatment, and eight of these had aggressive posterior retinopathy of prematurity (2.5% of all infants with retinopathy of prematurity). Mean gestational age was 24.2 weeks, mean birthweight was 634 g, and treatment occurred at mean 34.1 weeks post-menstrual age. The mean total number of burns per eye was 2967. Five of 15 treated eyes required retreatment. Two patients subsequently died of unrelated causes. Regression occurred in 9 of 11 remaining eyes; one eye progressed to stage 4b and another to stage 5 retinopathy of prematurity. Vitrectomy was performed in two eyes. Five eyes had 6/12 vision, one had 3/60, and three had no perception of light. Of the remaining two eyes, one had good fixation and the other had poor fixation. Despite good structural outcomes, visual outcomes for conventional laser treatment of aggressive posterior retinopathy of prematurity are poor. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  9. Treatment for stage 4A retinopathy of prematurity: laser and/or ranibizumab.

    Sukgen, Emine Alyamaç; Koçluk, Yusuf

    2017-02-01

    Stage 4A retinopathy of prematurity (ROP) is a critical phase where retinal detachment develops, but fovea is preserved. The present study aims to evaluate the effect of the first treatment choice (laser photocoagulation (LPC) or intravitreal ranibizumab (IVR)) applied in this critical phase on the prognosis of the disease. Records of patients diagnosed with stage 4A ROP and whose first treatment was applied in our clinic were evaluated retrospectively. All patients were referred to our clinic for the treatment of advanced ROP . While group 1 was composed of the patients who were administered LPC as first treatment, group 2 included patients where IVR was applied as first treatment. The patients in both groups were referred to surgical treatment in the presence of progression. The present study included a total of 31 eyes in 16 patients with stage 4A ROP. Eighteen eyes of nine patients in group 1 were first applied LPC, and 13 eyes of seven patients in group 2 were first applied intravitreal ranibizumab. While anatomic outcomes of ten eyes in both groups were favorable, eight eyes in group 1 and three eyes in group 2 displayed progression and were referred to vitreoretinal surgery. Laser and/or IVR treatment may be effective as a non-surgical treatment for stage 4A ROP. Especially stage 4A ROP until 6 clock hours can regress without surgical treatment. However, in stage 4A with involvement wider than 6 clock hours, non-surgical regression is difficult. Prospective controlled large series studies are necessary.

  10. Retinal Oximetry and Vessel Diameter Measurements With a Commercially Available Scanning Laser Ophthalmoscope in Diabetic Retinopathy.

    Blair, Norman P; Wanek, Justin; Felder, Anthony E; Joslin, Charlotte E; Kresovich, Jacob K; Lim, Jennifer I; Chau, Felix Y; Leiderman, Yannek; Shahidi, Mahnaz

    2017-10-01

    To test the hypothesis that retinal vascular diameter and hemoglobin oxygen saturation alterations, according to stages of diabetic retinopathy (DR), are discernible with a commercially available scanning laser ophthalmoscope (SLO). One hundred eighty-one subjects with no diabetes (No DM), diabetes with no DR (No DR), nonproliferative DR (NPDR), or proliferative DR (PDR, all had photocoagulation) underwent imaging with an SLO with dual lasers (532 nm and 633 nm). Customized image analysis software determined the diameters of retinal arteries and veins (DA and DV) and central retinal artery and vein equivalents (CRAE and CRVE). Oxygen saturations of hemoglobin in arteries and veins (SO2A and SO2V) were estimated from optical densities of vessels on images at the two wavelengths. Statistical models were generated by adjusting for effects of sex, race, age, eye, and fundus pigmentation. DA, CRAE, and CRVE were reduced in PDR compared to No DM (P ≤ 0.03). DV and CRVE were similar between No DM and No DR, but they were higher in NPDR than No DR (P ≤ 0.01). Effect of stage of disease on SO2A differed by race, being increased relative to No DM in NPDR and PDR in Hispanic participants only (P ≤ 0.02). Relative to No DM, SO2V was increased in NPDR and PDR (P ≤ 0.05). Alterations in retinal vascular diameters and SO2 by diabetic retinopathy stage can be detected with a widely available SLO, and covariates such as race can influence the results.

  11. New power lasers

    Yamanaka, Masanobu; Daido, Hiroyuki; Imasaki, Kazuo.

    1989-01-01

    As the new power lasers which are expected to exert large extending effect to the fields of advanced science and technology including precision engineering as well as laser nuclear fusion, LD-excited solid laser, X-ray laser and free electron laser are taken up and outlined. Recently, the solid laser using high power output, high efficiency semiconductor laser as the exciting beam source has been developed. This is called laser diode (LD)-excited solid laser, and the heightening of power output and efficiency and the extension of life are planned. Its present status and application to medical use, laser machining, laser soldering and so on are described. In 1960, the laser in visible region appeared, however in 1985, the result of observing induced emission beam by electron collision exciting method was reported in USA. In the wavelength range of 200 A, holography and contact X-ray microscope applications were verified. The various types of soft X-ray laser and the perspective hereafter are shown. The principle of free electron laser is explained. In the free electron laser, wavelength can be changed by varying electron beam energy, the period of wiggler magnetic field and the intensity of magnetic field. Further, high efficiency and large power output are possible. Its present status, application and the perspective hereafter are reported. (K.I.)

  12. Laser applications in materials processing

    Ready, J.F.

    1980-01-01

    The seminar focused on laser annealing of semiconductors, laser processing of semiconductor devices and formation of coatings and powders, surface modification with lasers, and specialized laser processing methods. Papers were presented on the theoretical analysis of thermal and mass transport during laser annealing, applications of scanning continuous-wave and pulsed lasers in silicon technology, laser techniques in photovoltaic applications, and the synthesis of ceramic powders from laser-heated gas-phase reactants. Other papers included: reflectance changes of metals during laser irradiation, surface-alloying using high-power continuous lasers, laser growth of silicon ribbon, and commercial laser-shock processes

  13. Raman fiber lasers

    2017-01-01

    This book serves as a comprehensive, up-to-date reference about this cutting-edge laser technology and its many new and interesting developments. Various aspects and trends of Raman fiber lasers are described in detail by experts in their fields. Raman fiber lasers have progressed quickly in the past decade, and have emerged as a versatile laser technology for generating high power light sources covering a spectral range from visible to mid-infrared. The technology is already being applied in the fields of telecommunication, astronomy, cold atom physics, laser spectroscopy, environmental sensing, and laser medicine. This book covers various topics relating to Raman fiber laser research, including power scaling, cladding and diode pumping, cascade Raman shifting, single frequency operation and power amplification, mid-infrared laser generation, specialty optical fibers, and random distributed feedback Raman fiber lasers. The book will appeal to scientists, students, and technicians seeking to understand the re...

  14. Ceramic Laser Materials

    Guillermo Villalobos

    2012-02-01

    Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

  15. Infrared laser system

    Cantrell, C.D.; Carbone, R.J.

    1977-01-01

    An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture

  16. Ceramic Laser Materials

    Sanghera, Jasbinder; Kim, Woohong; Villalobos, Guillermo; Shaw, Brandon; Baker, Colin; Frantz, Jesse; Sadowski, Bryan; Aggarwal, Ishwar

    2012-01-01

    Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements. PMID:28817044

  17. Spectroscopic and imaging diagnostics of pulsed laser deposition laser plasmas

    Thareja, Raj K.

    2002-01-01

    An overview of laser spectroscopic techniques used in the diagnostics of laser ablated plumes used for thin film deposition is given. An emerging laser spectroscopic imaging technique for the laser ablation material processing is discussed. (author)

  18. Lasers in periodontics.

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-08-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20(th) century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

  19. Excimer laser applications

    Fantoni, R.

    1988-01-01

    This lecture deals with laser induced material photoprocessing, especially concerning those processes which are initiated by u.v. lasers (mostly excimer laser). Advantages of using the u.v. radiation emitted by excimer lasers, both in photophysical and photochemical processes of different materials, are discussed in detail. Applications concerning microelectronics are stressed with respect to other applications in different fields (organic chemistry, medicine). As further applications of excimer lasers, main spectroscopic techniques for ''on line'' diagnostics which employ excimer pumped dye lasers, emitting tunable radiation in the visible and near u.v. are reviewed

  20. Lasers in chemical processing

    Davis, J.I.

    1982-01-01

    The high cost of laser energy is the crucial issue in any potential laser-processing application. It is expensive relative to other forms of energy and to most bulk chemicals. We show those factors that have previously frustrated attempts to find commercially viable laser-induced processes for the production of materials. Having identified the general criteria to be satisfied by an economically successful laser process and shown how these imply the laser-system requirements, we present a status report on the uranium laser isotope separation (LIS) program at the Lawrence Livermore National Laboratory

  1. Laser in urology. Laser i urologien

    Breisland, H.O. (Aker Sykehus, Oslo (Norway))

    1991-09-01

    The neodymium YAG laser is particularly suited for endoscopic urologic surgery because the YAG laser light can be conducted in flexible fibers. Superficial bladder tumours can be treated under local anaesthesia in the outpatient department. The frequency of local recurrences is low, significantly lower than after electrosection or electrocoagulation. Selected cases of T2-muscle invasive bladder tumours can be cured with laser coagulation applied subsequently to transurethral resection. Combined treatment with electrosection and laser coagulation of localized prostatic cancer is a promising method which compares favourably with results obtained by other treatment modalities. Tumours in the upper urinary tract can be laser-treated through ureteroscopes or nephroscopes, but the treatment should be limited to low stage, low grade tumours. Laser is the treatment of choice for intraurethral condylomatas. Laser treatment of penil carcinoma gives excellent cosmetic and functional results and few local recurrences. Laser lithotripsy is a new technique for treatment of ureteric stones and photodynamic laser therapy is a promising tecnique for treatment of carcinoma in situ in the bladder empithelium. However, neither of these techniques are available for clinical use in Norway as yet. 17 refs., 3 figs., 1 tabs.

  2. Laser materials processing with diode lasers

    Li, Lin; Lawrence, Jonathan; Spencer, Julian T.

    1996-01-01

    Laser materials processing is currently dominated by CO2, Nd-YAG and Excimer lasers. Continuous advances in semiconductor laser technology over the last decade have increased the average power output of the devices annualy by two fold, resulting in the commercial availability of the diode lasers today with delivery output powers in excess of 60W in CW mode and 5kW in qasi-CW mode. The advantages of compactness, high reliability, high efficiency and potential low cost, due to the mass producti...

  3. 1982 laser program annual report

    Hendricks, C.D.; Grow, G.R.

    1983-08-01

    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications

  4. Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

    Shirakawa, A.; Chen, M.; Suzuki, Y.

    2014-01-01

    Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

  5. Laser in operative dentistry

    E. Yasini

    1994-06-01

    Full Text Available Today laser has a lot of usage in medicine and dentistry. In the field of dentistry, laser is used in soft tissue surgery, sterilization of canals (in root canal therapy and in restorative dentistry laser is used for cavity preparation, caries removal, sealing the grooves (in preventive dentistry, etching enamel and dentin, composite polymerization and removal of tooth sensitivity. The use of Co2 lasers and Nd: YAG for cavity preparation, due to creating high heat causes darkness and cracks around the region of laser radiation. Also due to high temperature of these lasers, pulp damage is inevitable. So today, by using the Excimer laser especially the argon floride type with a wavelength of 193 nm, the problem of heat stress have been solved, but the use of lasers in dentistry, especially for cavity preparation needs more researches and evaluations.

  6. Laser for fusion energy

    Holzrichter, J.F.

    1995-01-01

    Solid state lasers have proven to be very versatile tools for the study and demonstration of inertial confinement fusion principles. When lasers were first contemplated to be used for the compression of fusion fuel in the late 1950s, the laser output energy levels were nominally one joule and the power levels were 10 3 watts (pulse duration's of 10 -3 sec). During the last 25 years, lasers optimized for fusion research have been increased in power to typically 100,000 joules with power levels approaching 10 14 watts. As a result of experiments with such lasers at many locations, DT target performance has been shown to be consistent with high gain target output. However, the demonstration of ignition and gain requires laser energies of several megajoules. Laser technology improvements demonstrated over the past decade appear to make possible the construction of such multimegajoule lasers at affordable costs. (author)

  7. Radiological protection against lasers

    Ballereau, P

    1974-04-01

    A brief description of the biological effects of laser beams is followed by a review of the factors involved in eye and skin damage (factors linked with the nature of lasers and those linked with the organ affected) and a discussion of the problems involved in the determination of threshold exposure levels. Preventive measures are recommended, according to the type of laser (high-energy pulse laser, continuous laser, gas laser). No legislation on the subject exists in France or in Europe. Types of lasers marketed, threshold exposure levels for eye and skin, variations of admissible exposure levels according to wavelength, etc. are presented in tabular form. Nomogram for determination of safe distance for direct vision of a laser is included.

  8. Advances in Fiber Lasers

    Morse, T

    1999-01-01

    Most of the time of this contract has been devoted toward improvements in optical fiber lasers and toward gathering experience to improve our program in high power, cladding pumped optical fiber lasers...

  9. Laser Processing and Chemistry

    Bäuerle, Dieter

    2011-01-01

    This book gives an overview of the fundamentals and applications of laser-matter interactions, in particular with regard to laser material processing. Special attention is given to laser-induced physical and chemical processes at gas-solid, liquid-solid, and solid-solid interfaces. Starting with the background physics, the book proceeds to examine applications of lasers in “standard” laser machining and laser chemical processing (LCP), including the patterning, coating, and modification of material surfaces. This fourth edition has been enlarged to cover the rapid advances in the understanding of the dynamics of materials under the action of ultrashort laser pulses, and to include a number of new topics, in particular the increasing importance of lasers in various different fields of surface functionalizations and nanotechnology. In two additional chapters, recent developments in biotechnology, medicine, art conservation and restoration are summarized. Graduate students, physicists, chemists, engineers, a...

  10. Fiber Laser Array

    Simpson, Thomas

    2002-01-01

    ...., field-dependent, loss within the coupled laser array. During this program, Jaycor focused on the construction and use of an experimental apparatus that can be used to investigate the coherent combination of an array of fiber lasers...

  11. ISTEF Laser Radar Program

    Stryjewski, John

    1998-01-01

    The BMDO Innovative Science and Technology Experimentation Facility (BMDO/ISTEF) laser radar program is engaged in an ongoing program to develop and demonstrate advanced laser radar concepts for Ballistic Missile Defense (BMD...

  12. Wavelength sweepable laser source

    2014-01-01

    Wavelength sweepable laser source is disclosed, wherein the laser source is a semiconductor laser source adapted for generating laser light at a lasing wavelength. The laser source comprises a substrate, a first reflector, and a second reflector. The first and second reflector together defines...... and having a rest position, the second reflector and suspension together defining a microelectromechanical MEMS oscillator. The MEMS oscillator has a resonance frequency and is adapted for oscillating the second reflector on either side of the rest position.; The laser source further comprises electrical...... connections adapted for applying an electric field to the MEMS oscillator. Furthermore, a laser source system and a method of use of the laser source are disclosed....

  13. Laser surgery - skin

    ... Bleeding Problem not going away Infection Pain Scarring Skin color changes Some laser surgery is done when you are asleep and ... TG, Elston DM, eds. Andrews' Diseases of the Skin: Clinical ... lasers, lights, and tissue interactions. In: Hruza GJ, Avram ...

  14. Laser in operative dentistry

    E. Yasini; Gh. Rahbari; A. Matorian

    1994-01-01

    Today laser has a lot of usage in medicine and dentistry. In the field of dentistry, laser is used in soft tissue surgery, sterilization of canals (in root canal therapy) and in restorative dentistry laser is used for cavity preparation, caries removal, sealing the grooves (in preventive dentistry), etching enamel and dentin, composite polymerization and removal of tooth sensitivity. The use of Co2 lasers and Nd: YAG for cavity preparation, due to creating high heat causes darkness and cracks...

  15. Tunable laser optics

    Duarte, FJ

    2015-01-01

    This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

  16. Laser cutting system

    Dougherty, Thomas J

    2015-03-03

    A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

  17. Dynamic changes of photorecrptor layer in eyes with acute central serous chorioretinopathy after laser treatment by fourier-domain optical coherence tomography%应用 FD-OCT 动态观察急性 CSCR激光后光感受器层的变化

    周丽琴; 王毅; 王晟; 孔琛柯

    2014-01-01

    AIM:To dynamically observe the feeling change of the photorecrptor layer in the eyes with acute central serous chorioretinopathy ( CSCR ) krypton laser treatment by fourier- domain optical coherence tomography ( FD -OCT ), and to study their correlation with the chang of vision. METHODS: This is a retrospective case series study. The clinical diagnosis of 52 patients with monocular initial onset of central serous chorioretinopathy, krypton laser photocoagulation before treatment, after 1,2,4,6,8wk,6mo, FD - OCT were performed to observe the morphological changes characteristic of photoreceptor layer and changes in vision. RESULTS: After 1wk treatment, all cases were improved;2wk,6 cases were cured;4wk,38 cases were cured;6wk,41 cases were cured;8wk,45 cases were cured, the OCT showed macular retinal neuroepithelial layer ( RNL ) from fully absorbed;6mo with the same 8wk. Before and after treatment in patients with best corrected visual acuity and from the height difference between the macular region of RNL was statistically significant (P CONCLUSION:FD-OCT can dynamicaly observed acute central serous chorioretinopathy krypton laser treatment of photoreceptor ultrastruture changes. Photoreceptor layer of complete and incomplete best corrected visual acuity difference was statistically significant (P METHODS: This is a retrospective case series study. The clinical diagnosis of 52 patients with monocular initial onset of central serous chorioretinopathy, krypton laser photocoagulation before treatment, after 1, 2, 4, 6, 8wk, 6mo, FD - OCT were performed to observe the morphological changes characteristic of photoreceptor layer and changes in vision. RESULTS: After 1wk treatment, all cases were improved; 2wk, 6 cases were cured; 4wk, 38 cases were cured; 6wk, 41 cases were cured; 8wk, 45 cases were cured, the OCT showed macular retinal neuroepithelial layer ( RNL ) from fully absorbed; 6mo with the same 8wk. Before and after treatment in patients with best corrected

  18. Application of Various Lasers to Laser Trimming Resistance System

    SUN Ji-feng

    2007-01-01

    Though the laser trimming resistance has been an old laser machining industry for over 30 years, the development of technology brings new alternative lasers which can be used for the traditional machining. The paper describes application of various lasers to laser trimming resistance system including early traditional krypton arc lamp pumped Nd:YAG to laser, modern popular diode pumped solid state laser and the present advanced harmonic diode pumped solid state laser. Using the new alternative lasers in the laser trimming resistance system can dramatically improve the yields and equipment performance.

  19. Laser technologies for laser accelerators. Annual report

    1985-01-01

    The primary result of the work reported is the determination of laser system architectures that satsify the requirements of high luminosity, high energy (about 1 TeV), electron accelerators. It has been found that high laser efficiency is a very hard driver for these accelerators as the total average laser output optical power is likely to fall above 10 MW. The luminosity requires rep rates in the kHz range, and individual pulse lengths in the 1-10 psec range are required to satisfy acceleration gradient goals. CO 2 and KrF lasers were chosen for study because of their potential to simultaneously satisfy the given requirements. Accelerator luminosity is reviewed, and requirements on laser system average power and rep rate are determined as a function of electron beam bunch parameters. Laser technologies are reviewed, including CO 2 , excimers, solid state, and free electron lasers. The proposed accelerator mechanisms are summarized briefly. Work on optical transport geometries for near and far field accelerators are presented. Possible exploitation of the CO 2 and DrF laser technology to generate the required pulse lengths, rep rates, and projected efficiencies is illustrated and needed development work is suggested. Initial efforts at developing a 50 GeV benchmark conceptual design and a 100 MeV demonstration experiment conceptual design are presented

  20. Laser induced pyrolysis techniques

    Vanderborgh, N.E.

    1976-01-01

    The application of laser pyrolysis techniques to the problems of chemical analysis is discussed. The processes occurring during laser pyrolysis are first briefly reviewed. The problems encountered in laser pyrolysis gas chromatography are discussed using the analysis of phenanthrene and binary hydrocarbons. The application of this technique to the characterization of naturally occurring carbonaceous material such as oil shales and coal is illustrated

  1. Solar pumped laser

    Lee, J. H.; Hohl, F.; Weaver, W. R. (Inventor)

    1984-01-01

    A solar pumped laser is described in which the lasant is a gas that will photodissociate and lase when subjected to sunrays. Sunrays are collected and directed onto the gas lasant to cause it to lase. Applications to laser propulsion and laser power transmission are discussed.

  2. Introducing the Yellow Laser

    Lincoln, James

    2018-01-01

    The author has acquired a yellow laser with the specific wavelength of 589 nm. Because this is the first time such a laser has been discussed in this journal, I feel it is appropriate to provide a discussion of its function and capabilities. Normal laser safety should be employed, such as not pointing it into eyes or at people, and using eye…

  3. Coatings for laser fusion

    Lowdermilk, W.H.

    1981-01-01

    Optical coatings are used in lasers systems for fusion research to control beam propagation and reduce surface reflection losses. The performance of coatings is important in the design, reliability, energy output, and cost of the laser systems. Significant developments in coating technology are required for future lasers for fusion research and eventual power reactors

  4. uv dye lasers

    Abakumov, G.A.; Fadeev, V.V.; Khokhlov, R.V.; Simonov, A.P.

    1975-01-01

    The most important property of visible dye lasers, that is, continuous wavelength tuning, stimulated the search for dyes capable to lase in uv. They were found in 1968. Now the need for tunable uv lasers for applications in spectroscopy, photochemistry, isotope separation, remote air and sea probing, etc. is clearly seen. A review of some recent advances in uv dye lasers is reviewed

  5. LaserFest Celebration

    Dr. Alan Chodos; Elizabeth A. Rogan

    2011-08-25

    LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) Laser Days.

  6. Laser beam cutting method. Laser ko ni yoru kaitai koho

    Kutsumizu, A. (Obayashi Corp., Osaka (Japan))

    1991-07-01

    In this special issue paper concerning the demolition of concrete structures, was introduced a demolition of concrete structures using laser, of which practical application is expected due to the remarkable progress of generating power and efficiency of laser radiator. The characteristics of laser beam which can give a temperature of one million centigrade at the irradiated spot, the laser radiator consisting of laser medium, laser resonator and pumping apparatus, and the laser kinds for working, such as CO{sub 2} laser, YAG laser and CO laser, were described. The basic constitution of laser cutting equipment consisting of large generating power radiator, beam transmitter, beam condenser, and nozzle for working was also illustrated. Furthermore, strong and weak points in the laser cutting for concrete and reinforcement were enumerated. Applications of laser to cutting of reinforced and unreinforced concrete constructions were shown, and the concept and safety measure for application of laser to practical demolition was discussed. 5 refs., 8 figs.

  7. Rubber band ligation and infrared photocoagulation for the outpatient treatment of hemorrhoidal disease Ligadura elástica e fotocoagulação com radiação infravermelha no tratamento ambulatorial da doença hemorroidária

    Maurício Pichler Ricci

    2008-02-01

    Full Text Available PURPOSE: To compare the results of rubber band ligation and infrared photocoagulation for the treatment of hemorrhoidal disease through the analysis of the incidence of complications after each treatment and respective success rate. METHODS: Forty-eight patients with first, second or third degree hemorrhoidal disease were randomized to recieve treatment with either rubber band ligation (n=23 or infrared photocoagulation (n=25. Each patient was assessed at 1 week and 4 week intervals after treatment. We compared the incidence of complications and efficiency of each treatment modality and Qui-square, Fisher's Exact Test and Student's t Test were used to statistical analysis. RESULTS: Bleeding occured in eigth (34,7% patients treated with rubber band ligation and in four (16,0% after infrared photocoagulation (p=0,243. Thirteen (52,0% patients felt pain during infrared photocoagulation and 9 (39,1% after rubber band ligation (p=0,546. After rubber band ligation, 14 (60,8% required medication for pain relief. One patient (4,0% required medication after infrared photocoagulation (pOBJETIVO: Comparar os resultados da ligadura elástica com os da fotocoagulação com radiação infravermelha no tratamento da doença hemorroidária através da análise de suas respectivas morbidades e eficácia. MÉTODOS: Foi realizado ensaio clínico casualisado com 48 pacientes portadores de doença hemorroidária graus I, II e III. Após randomização, os pacientes foram submetidos à ligadura elástica (n=23 ou fotocoagulação com radiação infravermelha (n=25. Os pacientes compareceram para consulta ambulatorial 1 semana e 4 semanas após o procedimento. A avaliação foi feita através da análise da incidência de morbidades após cada procedimento e eficácia, com quatro semanas de acompanhamento. As análises estatísticas foram realizadas através do teste do Qui-quadrado, Teste Exato de Fisher e Teste t de Student. RESULTADOS: Dos pacientes submetidos

  8. Introduction to laser technology

    Hitz, C Breck; Hecht, Jeff; Hitz, C Breck; John Wiley & Sons

    2001-01-01

    Electrical Engineering Introduction to Laser Technology , Third Edition. Would you like to know how a laser works, and how it can be modified for your own specific tasks? This intuitive third edition-previously published as Understanding Laser Technology , First and Second Editions-introduces engineers, scientists, technicians, and novices alike to the world of modern lasers, without delving into the mathematical details of quantum electronics. It is the only introductory text on the market today that explains the underlying physics and engineering applicable to all lasers. A unique combinatio.

  9. Quantum well lasers

    Zory, Jr, Peter S; Kelley, Paul

    1993-01-01

    This book provides the information necessary for the reader to achieve a thorough understanding of all aspects of QW lasers - from the basic mechanism of optical gain, through the current technolgoical state of the art, to the future technologies of quantum wires and quantum dots. In view of the growing importance of QW lasers, this book should be read by all those with an active interest in laser science and technology, from the advanced student to the experienced laser scientist.* The first comprehensive book-length treatment of quantum well lasers* Provides a detailed treatment

  10. Coherent laser beam combining

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  11. The laser thermonuclear fusion

    Coutant, J.; Dautray, R.; Decroisette, M.; Watteau, J.P.

    1987-01-01

    Principle of the thermonuclear fusion by inertial confinement: required characteristics of the deuterium-tritium plasma and of the high power lasers to be used Development of high power lasers: active media used; amplifiers; frequency conversion; beam quality; pulse conditioning; existing large systems. The laser-matter interaction: collision and collective interaction of the laser radiation with matter; transport of the absorbed energy; heating and compression of deuterium-tritium; diagnoses and their comparison with the numerical simulation of the experiment; performances. Conclusions: difficulties to overcome; megajoule lasers; other energy source: particles beams [fr

  12. Laser Cutting, Development Trends

    Olsen, Flemming Ove

    1999-01-01

    In this paper a short review of the development trends in laser cutting will be given.The technology, which is the fastest expanding industrial production technology will develop in both its core market segment: Flat bed cutting of sheet metal, as it will expand in heavy industry and in cutting...... of 3-dimensional shapes.The CO2-laser will also in the near future be the dominating laser source in the market, although the new developments in ND-YAG-lasers opens for new possibilities for this laser type....

  13. Lasers in space.

    Michaelis, MM

    2008-04-01

    Full Text Available cube, laser beam reflectors, placed on the Moon half a century ago. These early achievements will soon be followed by a plethora of experiments involving lasers in low earth orbit (LEO) or at Lagrange points. And not much later, laser communications... will stretch out as far as Mars and beyond. One important low Earth orbit (LEO) application is the removal of space debris by Earth based or LEO relayed lasers as promoted by Phipps et al.3. Another is military communication. The prominent L1 laser space...

  14. Tunable laser applications

    Duarte, FJ

    2008-01-01

    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  15. New solid laser: Ceramic laser. From ultra stable laser to ultra high output laser

    Ueda, Kenichi

    2006-01-01

    An epoch-making solid laser is developed. It is ceramic laser, polycrystal, which is produced as same as glass and shows ultra high output. Ti 3+ :Al 2 O 3 laser crystal and the CPA (chirped pulse amplification) technique realized new ultra high output lasers. Japan has developed various kinds of ceramic lasers, from 10 -2 to 67 x 10 3 w average output, since 1995. These ceramic lasers were studied by gravitational radiation astronomy. The scattering coefficient of ceramic laser is smaller than single crystals. The new fast ignition method is proposed by Institute of Laser Engineering of Osaka University, Japan. Ultra-intense short pulse laser can inject the required energy to the high-density imploded core plasma within the core disassembling time. Ti 3+ :Al 2 O 3 crystal for laser, ceramic YAG of large caliber for 100 kW, transparent laser ceramic from nano-crystals, crystal grain and boundary layer between grains, the scattering coefficient of single crystal and ceramic, and the derived release cross section of Yb:YAG ceramic are described. (S.Y.)

  16. Advanced lasers for fusion

    Krupke, W.F.; George, E.V.; Haas, R.A.

    1979-01-01

    Laser drive systems' performance requirements for fusion reactors are developed following a review of the principles of inertial confinement fusion and of the technical status of fusion research lasers (Nd:glass; CO 2 , iodine). These requirements are analyzed in the context of energy-storing laser media with respect to laser systems design issues: optical damage and breakdown, medium excitation, parasitics and superfluorescence depumping, energy extraction physics, medium optical quality, and gas flow. Three types of energy-storing laser media of potential utility are identified and singled out for detailed review: (1) Group VI atomic lasers, (2) rare earth solid state hybrid lasers, and (3) rare earth molecular vapor lasers. The use of highly-radiative laser media, particularly the rare-gas monohalide excimers, are discussed in the context of short pulse fusion applications. The concept of backward wave Raman pulse compression is considered as an attractive technique for this purpose. The basic physics and device parameters of these four laser systems are reviewed and conceptual designs for high energy laser systems are presented. Preliminary estimates for systems efficiencies are given. (Auth.)

  17. Micromachining with copper lasers

    Knowles, Martyn R. H.; Bell, Andy; Foster-Turner, Gideon; Rutterford, Graham; Chudzicki, J.; Kearsley, Andrew J.

    1997-04-01

    In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

  18. Laser Applications in Orthodontics

    Heidari, Somayeh; Torkan, Sepideh

    2013-01-01

    A laser is a collimated single wavelength of light which delivers a concentrated source of energy. Soon after different types of lasers were invented, investigators began to examine the effects of different wavelengths of laser energy on oral tissues, routine dental procedures and experimental applications. Orthodontists, along with other specialist in different fields of dentistry, can now benefit from several different advantages that lasers provide during the treatment process, from the beginning of the treatment, when separators are placed, to the time of resin residues removal from the tooth surface at the end of orthodontic treatment. This article outlines some of the most common usages of laser beam in orthodontics and also provides a comparison between laser and other conventional method that were the standard of care prior to the advent of laser in this field. PMID:25606324

  19. ORION laser target diagnostics

    Bentley, C. D.; Edwards, R. D.; Andrew, J. E.; James, S. F.; Gardner, M. D.; Comley, A. J.; Vaughan, K.; Horsfield, C. J.; Rubery, M. S.; Rothman, S. D.; Daykin, S.; Masoero, S. J.; Palmer, J. B.; Meadowcroft, A. L.; Williams, B. M.; Gumbrell, E. T.; Fyrth, J. D.; Brown, C. R. D.; Hill, M. P.; Oades, K.

    2012-01-01

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  20. ORION laser target diagnostics.

    Bentley, C D; Edwards, R D; Andrew, J E; James, S F; Gardner, M D; Comley, A J; Vaughan, K; Horsfield, C J; Rubery, M S; Rothman, S D; Daykin, S; Masoero, S J; Palmer, J B; Meadowcroft, A L; Williams, B M; Gumbrell, E T; Fyrth, J D; Brown, C R D; Hill, M P; Oades, K; Wright, M J; Hood, B A; Kemshall, P

    2012-10-01

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  1. Robot-laser system

    Akeel, H.A.

    1987-01-01

    A robot-laser system is described for providing a laser beam at a desired location, the system comprising: a laser beam source; a robot including a plurality of movable parts including a hollow robot arm having a central axis along which the laser source directs the laser beam; at least one mirror for reflecting the laser beam from the source to the desired location, the mirror being mounted within the robot arm to move therewith and relative thereto to about a transverse axis that extends angularly to the central axis of the robot arm; and an automatic programmable control system for automatically moving the mirror about the transverse axis relative to and in synchronization with movement of the robot arm to thereby direct the laser beam to the desired location as the arm is moved

  2. Laser safety in dentistry

    Wigdor, Harvey A.

    1997-05-01

    One of the major causes of anxiety in the dental clinic is the dental handpiece. Because dentists wish to provide a method which can replace the drill there has often been a premature use of the laser in dentistry. Various lasers have been introduced into the clinic before research has shown the laser used is of clinical benefit. Any new treatment method must not compromise the health of the patient being treated. Thus a method of evaluating the clinical abilities of dentists and their understanding the limitations of the laser used must be developed. Dentist must be trained in the basic interaction of the laser on oral tissues. The training has to concentrate on the variation of the laser wavelength absorption in the different tissues of the oral cavity. Because of the differences in the optical properties of these tissues great care must be exercised by practitioners using lasers on patients.

  3. Lasers in materials science

    Ossi, Paolo; Zhigilei, Leonid

    2014-01-01

    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  4. Alternate laser fusion drivers

    Pleasance, L.D.

    1979-11-01

    One objective of research on inertial confinement fusion is the development of a power generating system based on this concept. Realization of this goal will depend on the availability of a suitable laser or other system to drive the power plant. The primary laser systems used for laser fusion research, Nd 3+ : Glass and CO 2 , have characteristics which may preclude their use for this application. Glass lasers are presently perceived to be incapable of sufficiently high average power operation and the CO 2 laser may be limited by and issues associated with target coupling. These general perceptions have encouraged a search for alternatives to the present systems. The search for new lasers has been directed generally towards shorter wavelengths; most of the new lasers discovered in the past few years have been in the visible and ultraviolet region of the spectrum. Virtually all of them have been advocated as the most promising candidate for a fusion driver at one time or another

  5. Flexible Laser Metal Cutting

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

    2014-01-01

    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

  6. Lasers: principles, applications and energetic measures

    Subran, C.; Sagaut, J.; Lapointe, S.

    2009-01-01

    After having recalled the principles of a laser and the properties of the laser beam, the authors describe the following different types of lasers: solid state lasers, fiber lasers, semiconductor lasers, dye lasers and gas lasers. Then, their applications are given. Very high energy lasers can reproduce the phenomenon of nuclear fusion of hydrogen atoms. (O.M.)

  7. Lasers in space

    Michaelis, M. M.; Forbes, A.; Bingham, R.; Kellett, B. J.; Mathye, A.

    2008-05-01

    A variety of laser applications in space, past, present, future and far future are reviewed together with the contributions of some of the scientists and engineers involved, especially those that happen to have South African connections. Historically, two of the earliest laser applications in space, were atmospheric LIDAR and lunar ranging. These applications involved atmospheric physicists, several astronauts and many of the staff recruited into the Soviet and North American lunar exploration programmes. There is a strong interest in South Africa in both LIDAR and lunar ranging. Shortly after the birth of the laser (and even just prior) theoretical work on photonic propulsion and space propulsion by laser ablation was initiated by Georgii Marx, Arthur Kantrowitz and Eugen Saenger. Present or near future experimental programs are developing in the following fields: laser ablation propulsion, possibly coupled with rail gun or gas gun propulsion; interplanetary laser transmission; laser altimetry; gravity wave detection by space based Michelson interferometry; the de-orbiting of space debris by high power lasers; atom laser interferometry in space. Far future applications of laser-photonic space-propulsion were also pioneered by Carl Sagan and Robert Forward. They envisaged means of putting Saenger's ideas into practice. Forward also invented a laser based method for manufacturing solid antimatter or SANTIM, well before the ongoing experiments at CERN with anti-hydrogen production and laser-trapping. SANTIM would be an ideal propellant for interstellar missions if it could be manufactured in sufficient quantities. It would be equally useful as a power source for the transmission of information over light year distances. We briefly mention military lasers. Last but not least, we address naturally occurring lasers in space and pose the question: "did the Big Bang lase?"

  8. Laser system using ultra-short laser pulses

    Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI

    2009-10-27

    A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

  9. Designing of Raman laser

    Zidan, M. D.; Al-Awad, F.; Alsous, M. B.

    2005-01-01

    In this work, we describe the design of the Raman laser pumped by Frequency doubled Nd-YAG laser (λ=532 nm) to generate new laser wavelengths by shifting the frequency of the Nd-YAG laser to Stokes region (λ 1 =683 nm, λ 2 =953.6 nm, λ 3 =1579.5 nm) and Antistokes region (λ ' 1 =435 nm, λ ' 2 =369.9 nm, λ ' 3=319.8 nm). Laser resonator has been designed to increase the laser gain. It consists of two mirrors, the back mirror transmits the pump laser beam (λ=532 nm) through the Raman tube and reflects all other generated Raman laser lines. Four special front mirrors were made to be used for the four laser lines λ 1 =683 nm, λ 2 =953.6 nm and λ ' 1 = 435 nm, λ ' 2 =369.9 nm. The output energy for the lines υ 1 s, υ 2 s, υ 1 as,υ 2 as was measured. The output energy of the Raman laser was characterized for different H 2 pressure inside the tube. (Author)

  10. Laser program overview

    Storm, E.; Coleman, L.W.

    1985-01-01

    The objectives of the Lawrence Livermore National Laboratory Laser Fusion program are to understand and develop the science and technology of inertial confinement fusion (ICF), and to utilize ICF in short- and long-term military applications, and, in the long-term, as a candidate for central-station civilian power generation. In 1984, using the Novette laser system, the authors completed experiments showing the very favorable scaling of laser-plama interactions with short-wavelength laser light. Their Novette experiments have unequivocally shown that short laser wavelength, i.e., less than 1 μm, is required to provide the drive necessary for efficient compression, ignition, and burn of DT fusion fuel. In other experiments with Novette, the authors made the first unambiguous observation of amplified spontaneous emission in the soft x-ray regime. The authors also conducted military applications and weapons physics experiments, which they discuss in detail in the classified volume of our Laser Program Annual Report. In the second thrust, advanced laser studies, they develop and test the concepts, components, and materials for present and future laser systems. Over the years, this has meant providing the technology base and scientific advances necessary to construct and operate a succession of six evermore-powerful laser systems. The latest of these, Nova, a 100-TW/100-kJ-class laser system, was completed in 1984. The Nd:glass laser continues to be the most effective and versatile tool for ICF and weapons physics because of its scalability in energy, the ability to efficiently convert its 1=μm output to shorter wavelengths, its ability to provide flexible, controlled pulse shaping, and its capability to adapt to a variety of irradiation and focusing geometries. For these reasons, many of our advanced laser studies are in areas appropriate to solid state laser technologies

  11. Laser pumped lasers for isotope separation

    Fry, S.M.

    1976-01-01

    A study of the isotope separation laser requirements reveals that high pressure polyatomic molecular gas laser pumped lasers can attain the necessary characteristics including tunability, energy output, pulse width, and repetition rate. The results of a search, made for molecules meeting the appropriate requirements for one of several pump schemes utilizing a CO 2 laser and with output in the 12 μm or 16μm wavelength range, are presented. Several methods of pumping are reviewed and two novel pump schemes are presented. A laser pumped laser device design is given, and operation of this device and associated diagnostic equipment is confirmed by repeating experiments in OCS and NH 3 . The results of OCS laser experiments show that an improvement in pump rate and output per unit length is obtained with the device, using a wedged transverse pumping scheme. A new multi-line laser system in NH 3 pumped by a TEA CO 2 laser is reported. More than forty transitions spanning the wavelength range of 9.2 to 13.8 μm are observed and identified. A strong output at 12.08 μm is one of the closest lines yet found to the required laser isotope separation wavelength. Far infrared emission near 65 μm is observed and is responsible for populating levels which lase in pure ammonia near 12.3 μm. Buffer gas (e.g., N 2 or He) pressures of approximately 40--800 torr cause energy transfer by collision-induced rotationaltransitions from the pumped antisymmetric to the lasing symmetric levels in the nu 2 = 1 band of ammonia. Most of the observed lines are aP(J,K) transitions which originate from the nu 2 /sup s/ band. Measurements of the pressure dependence of the laser output shows that some lines lase at pressures greater than one atmosphere. Transient behavior of the 12.08 μm line is calculated from a simplified analytic model and these calculations are compared to the experimental results

  12. Pattern Laser Annealing by a Pulsed Laser

    Komiya, Yoshio; Hoh, Koichiro; Murakami, Koichi; Takahashi, Tetsuo; Tarui, Yasuo

    1981-10-01

    Preliminary experiments with contact-type pattern laser annealing were made for local polycrystallization of a-Si, local evaporation of a-Si and local formation of Ni-Si alloy. These experiments showed that the mask patterns can be replicated as annealed regions with a resolution of a few microns on substrates. To overcome shortcomings due to the contact type pattern annealing, a projection type reduction pattern laser annealing system is proposed for resistless low temperature pattern forming processes.

  13. High energy HF pulsed lasers

    Patterson, E.L.; Gerber, R.A.

    1976-01-01

    Recent experiments show that pulsed HF lasers are capable of producing high energy with good efficiency. Preliminary experiments show that the laser radiation from the high-gain medium can be controlled with a low-power probe laser beam or with low-level feedback. These results indicate that the HF laser may have potential for second-generation laser fusion experiments

  14. Laser Safety Inspection Criteria

    Barat, K

    2005-01-01

    A responsibility of the Laser Safety Officer (LSO) is to perform laser safety audits. The American National Standard Z136.1 Safe use of Lasers references this requirement in several sections: (1) Section 1.3.2 LSO Specific Responsibilities states under Hazard Evaluation, ''The LSO shall be responsible for hazards evaluation of laser work areas''; (2) Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''; and (3) Appendix D, under Survey and Inspections, it states, ''the LSO will survey by inspection, as considered necessary, all areas where laser equipment is used''. Therefore, for facilities using Class 3B and or Class 4 lasers, audits for laser safety compliance are expected to be conducted. The composition, frequency and rigueur of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms. In many institutions, a sole Laser Safety Officer (LSO) or a number of Deputy LSO's perform these audits. For that matter, there are institutions that request users to perform a self-assessment audit. Many items on the common audit list and the associated findings are subjective because they are based on the experience and interest of the LSO or auditor in particular items on the checklist. Beam block usage is an example; to one set of eyes a particular arrangement might be completely adequate, while to another the installation may be inadequate. In order to provide more consistency, the National Ignition Facility Directorate at Lawrence Livermore National Laboratory (NIF-LLNL) has established criteria for a number of items found on the typical laser safety audit form. These criteria are distributed to laser users, and they serve two broad purposes: first, it gives the user an expectation of what will be reviewed by an auditor, and second, it is an

  15. Single frequency semiconductor lasers

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  16. Nuclear-pumped lasers

    Prelas, Mark

    2016-01-01

    This book focuses on Nuclear-Pumped Laser (NPL) technology and provides the reader with a fundamental understanding of NPLs, a review of research in the field, and exploration of large scale NPL system design and applications. Early chapters look at the fundamental properties of lasers, nuclear-pumping and nuclear reactions that may be used as drivers for nuclear-pumped lasers. The book goes on to explore the efficient transport of energy from the ionizing radiation to the laser medium and then the operational characteristics of existing nuclear-pumped lasers. Models based on Mathematica, explanations and a tutorial all assist the reader’s understanding of this technology. Later chapters consider the integration of the various systems involved in NPLs and the ways in which they can be used, including beyond the military agenda. As readers will discover, there are significant humanitarian applications for high energy/power lasers, such as deflecting asteroids, space propulsion, power transmission and mining....

  17. Power Laser Ablation Symposia

    Phipps, Claude

    2007-01-01

    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  18. Laser induced nuclear reactions

    Ledingham, Ken; McCanny, Tom; Graham, Paul; Fang Xiao; Singhal, Ravi; Magill, Joe; Creswell, Alan; Sanderson, David; Allott, Ric; Neely, David; Norreys, Peter; Santala, Marko; Zepf, Matthew; Watts, Ian; Clark, Eugene; Krushelnick, Karl; Tatarakis, Michael; Dangor, Bucker; Machecek, Antonin; Wark, Justin

    1998-01-01

    Dramatic improvements in laser technology since 1984 have revolutionised high power laser technology. Application of chirped-pulse amplification techniques has resulted in laser intensities in excess of 10 19 W/cm 2 . In the mid to late eighties, C. K. Rhodes and K. Boyer discussed the possibility of shining laser light of this intensity onto solid surfaces and to cause nuclear transitions. In particular, irradiation of a uranium target could induce electro- and photofission in the focal region of the laser. In this paper it is shown that μCi of 62 Cu can be generated via the (γ,n) reaction by a laser with an intensity of about 10 19 Wcm -2

  19. Lasers for isotope separation

    O'Hair, E.A.; Piltch, M.S.

    1976-01-01

    The Los Alamos Scientific Laboratory is conducting research on uranium enrichment. All processes being studied employ uranium molecules and use lasers to provide isotopic selectivity and enrichment. There are four well-defined infrared frequencies and two ultraviolet frequency bands of interest. The infrared frequencies are outside the range of the available lasers and an extensive research and development activity is currently underway. Lasers are available in the uv bands, however, much development work remains. The specification for the commercial uranium enrichment plant lasers will depend upon the results of the current enrichment experiments, the laser capital cost, reliability, and maintenance cost. For the processes under investigation there are specific photon requirements but latitude in how these requirements can be met. The final laser selections for the pilot plant need not be made until the mid-1980's. Between now and that time as extensive as possible a research and development effort will be maintained

  20. Inertial fusion by laser

    Dautray, R.; Watteau, J.-P.

    1980-01-01

    Following a brief historical survey of research into the effects of interaction of laser with matter, the principles of fusion by inertial confinement are described and the main parameters and possible levels given. The development of power lasers is then discussed with details of performances of the main lasers used in various laboratories, and with an assessment of the respective merits of neodymium glass, carbon dioxide or iodine lasers. The phenomena of laser radiation and its interaction with matter is then described, with emphasis on the results of experiments concerned with target implosion with the object of compressing and heating the mixture of heavy hydrogen and tritium to be ignited. Finally, a review is made of future possibilities opened up by the use of large power lasers which have recently become operational or are being constructed, and the ground still to be covered before a reactor can be produced [fr

  1. Principles of Lasers

    Svelto, Orazio

    2010-01-01

    This new Fifth Edition of Principles of Lasers incorporates corrections to the previous edition. The text’s essential mission remains the same: to provide a wide-ranging yet unified description of laser behavior, physics, technology, and current applications. Dr. Svelto emphasizes the physical rather than the mathematical aspects of lasers, and presents the subject in the simplest terms compatible with a correct physical understanding. Praise for earlier editions: "Professor Svelto is himself a longtime laser pioneer and his text shows the breadth of his broad acquaintance with all aspects of the field … Anyone mastering the contents of this book will be well prepared to understand advanced treatises and research papers in laser science and technology." (Arthur L. Schawlow, 1981 Nobel Laureate in Physics) "Already well established as a self-contained introduction to the physics and technology of lasers … Professor Svelto’s book, in this lucid translation by David Hanna, can be strongly recommended for...

  2. Atomic iodine laser

    Fisk, G.A.; Gusinow, M.A.; Hays, A.K.; Padrick, T.D.; Palmer, R.E.; Rice, J.K.; Truby, F.K.; Riley, M.E.

    1978-05-01

    The atomic iodine photodissociation laser has been under intensive study for a number of years. The physics associated with this system is now well understood and it is possible to produce a 0.1 nsec (or longer) near-diffraction-limited laser pulse which can be amplified with negligible temporal distortion and little spatial deformation. The output of either a saturated or unsaturated amplifier consists of a high-fidelity near-diffraction-limited, energetic laser pulse. The report is divided into three chapters. Chapter 1 is a survey of the important areas affecting efficient laser operation and summarizes the findings of Chap. 2. Chapter 2 presents detailed discussions and evaluations pertinent to pumps, chemical regeneration, and other elements in the overall laser system. Chapter 3 briefly discusses those areas that require further work and the nature of the work required to complete the full-scale evaluation of the applicability of the iodine photodissociation laser to the inertial confinement program

  3. Strong field laser physics

    2008-01-01

    Since the invention of the laser in the 1960s, people have strived to reach higher intensities and shorter pulse durations. High intensities and ultrashort pulse durations are intimately related. Recent developments have shown that high intensity lasers also open the way to realize pulses with the shortest durations to date, giving birth to the field of attosecond science (1 asec = 10-18s). This book is about high-intensity lasers and their applications. The goal is to give an up to date introduction to the technology behind these laser systems and to the broad range of intense laser applications. These applications include AMO (atomic molecular and optical) physics, x-ray science, attosecond science, plasma physics and particle acceleration, condensed matter science and laser micromachining, and finally even high-energy physics.

  4. Arduino based laser control

    Bernal Muñoz, Ferran

    2015-01-01

    ARDUINO is a vey usefull platform for prototypes. In this project ARDUINO will be used for controling a Semiconductor Tuneable Laser. [ANGLÈS] Diode laser for communications control based on an Arduino board. Temperature control implementation. Software and hardware protection for the laser implementation. [CASTELLÀ] Control de un láser de comunicaciones ópticas desde el ordenador utilizando una placa Arduino. Implementación de un control de temperatura y protección software y hardware ...

  5. Shiva laser system performance

    Glaze, J.; Godwin, R.O.; Holzrichter, J.F.

    1978-01-01

    On November 18, 1977, after four years of experimentation, innovation, and construction, the Shiva High Energy Laser facility produced 10.2 kJ of focusable laser energy delivered in a 0.95 ns pulse. The Shiva laser, with its computer control system and delta amplifiers, demonstrated its versatility on May 18, 1978, when the first 20-beam target shot with delta amplifiers focused 26 TW on a target and produced a yield of 7.5 x 10 9 neutrons

  6. Lasers in Ophthalmology

    1992-01-01

    In recent years,lasers have entered every fieldof medicine and especially so in ophthalmol-ogy.The scientific basis of lasers in ophthal-mology is based on three mechanisms:1.Photothermal effectLasers:argon,krypton,dye and diodeA thermal effect is generated when laserenergy is absorbed by pigment leading to in-creased vibration and therefore heat content.A

  7. Laser Journal (Selected Articles),

    1982-09-10

    laser is described. The apparatus structure and some experimental results are reported. MATERIAL AND ELEMENT MAGNETO -OPTIC PROPERTIES OF Pr dYb),(1oAI...with a magneto -optical modulator. The measuring system is simple and sensitive, with reading accuracy of ±0.0050 and error 45%. STUDY ON EXPERIMENTAL...laser radiation therapy . He Fang de East Chiia Hospital APPLICATION OF N4d,:Y q LASER TO TREAT INTERNAL HEMERRHOID Zhuo Ruilin Zu Songlin (Shanghai

  8. Laser precision microfabrication

    Sugioka, Koji; Pique, Alberto

    2010-01-01

    Miniaturization and high precision are rapidly becoming a requirement for many industrial processes and products. As a result, there is greater interest in the use of laser microfabrication technology to achieve these goals. This book composed of 16 chapters covers all the topics of laser precision processing from fundamental aspects to industrial applications to both inorganic and biological materials. It reviews the sate of the art of research and technological development in the area of laser processing.

  9. Lasers for the SILVA laser isotope separation process

    Lapierre, Y.

    1997-01-01

    The main principles of the laser isotope separation process for the production of enriched uranium at lower cost, are reviewed and the corresponding optimal laser characteristics are described. The development of the SILVA laser isotope separation process involved researches in the various domains of pump lasers, dye lasers, laser and optics systems and two test facilities for the feasibility studies which are expected for 1997

  10. High power lasers

    Niku-Lari, A

    1989-01-01

    The use of lasers for the working and treatment of materials is becoming increasingly common in industry. However, certain laser applications, for example, in welding, cutting and drilling, are more widely exploited than others. Whilst the potential of lasers for the surface treatment of metals is well recognised, in practice, this particular application is a relative newcomer. The 24 papers in this volume present the latest research and engineering developments in the use of lasers for processes such as surface melting, surface alloying and cladding, and machining, as well as discussing th

  11. Degenerate band edge laser

    Veysi, Mehdi; Othman, Mohamed A. K.; Figotin, Alexander; Capolino, Filippo

    2018-05-01

    We propose a class of lasers based on a fourth-order exceptional point of degeneracy (EPD) referred to as the degenerate band edge (DBE). EPDs have been found in parity-time-symmetric photonic structures that require loss and/or gain; here we show that the DBE is a different kind of EPD since it occurs in periodic structures that are lossless and gainless. Because of this property, a small level of gain is sufficient to induce single-frequency lasing based on a synchronous operation of four degenerate Floquet-Bloch eigenwaves. This lasing scheme constitutes a light-matter interaction mechanism that leads also to a unique scaling law of the laser threshold with the inverse of the fifth power of the laser-cavity length. The DBE laser has the lowest lasing threshold in comparison to a regular band edge laser and to a conventional laser in cavities with the same loaded quality (Q ) factor and length. In particular, even without mirror reflectors the DBE laser exhibits a lasing threshold which is an order of magnitude lower than that of a uniform cavity laser of the same length and with very high mirror reflectivity. Importantly, this novel DBE lasing regime enforces mode selectivity and coherent single-frequency operation even for pumping rates well beyond the lasing threshold, in contrast to the multifrequency nature of conventional uniform cavity lasers.

  12. Gigashot Optical Laser Demonstrator

    Deri, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-13

    The Gigashot Optical Laser Demonstrator (GOLD) project has demonstrated a novel optical amplifier for high energy pulsed lasers operating at high repetition rates. The amplifier stores enough pump energy to support >10 J of laser output, and employs conduction cooling for thermal management to avoid the need for expensive and bulky high-pressure helium subsystems. A prototype amplifier was fabricated, pumped with diode light at 885 nm, and characterized. Experimental results show that the amplifier provides sufficient small-signal gain and sufficiently low wavefront and birefringence impairments to prove useful in laser systems, at repetition rates up to 60 Hz.

  13. Notes on Laser Acceleration

    Tajima, T.

    2008-01-01

    This note intends to motivate our effort toward the advent of new methods of particle acceleration, utilizing the fast rising laser technology. By illustrating the underlying principles in an intuitive manner and thus less jargon-clad fashion, we seek a direction in which we shall be able to properly control and harness the promise of laser acceleration. First we review the idea behind the laser wakefield. We then go on to examine ion acceleration by laser. We examine the sheath acceleration in particular and look for the future direction that allows orderly acceleration of ions in high energies

  14. X-ray lasers

    Elton, Raymond C

    2012-01-01

    The first in its field, this book is both an introduction to x-ray lasers and a how-to guide for specialists. It provides new entrants and others interested in the field with a comprehensive overview and describes useful examples of analysis and experiments as background and guidance for researchers undertaking new laser designs. In one succinct volume, X-Ray Lasers collects the knowledge and experience gained in two decades of x-ray laser development and conveys the exciting challenges and possibilities still to come._Add on for longer version of blurb_M>The reader is first introduced

  15. Lasers in materials processing

    Davis, J.I.; Rockower, E.B.

    1981-01-01

    A status report on the uranium Laser Isotope Separation (LIS) Program at the Lawrence Livermore National Laboratory is presented. Prior to this status report, process economic analysis is presented so as to understand how the unique properties of laser photons can be best utilized in the production of materials and components despite the high cost of laser energy. The characteristics of potential applications that are necessary for success are identified, and those factors that have up to now frustrated attempts to find commercially viable laser induced chemical and physical process for the production of new or existing materials are pointed out

  16. Mid-Infrared Lasers

    National Aeronautics and Space Administration — Mid infrared solid state lasers for Differential Absorption Lidar (DIAL) systems required for understanding atmospheric chemistry are not available. This program...

  17. Laser fusion program overview

    Emmett, J.L.

    1977-01-01

    This program is structured to proceed through a series of well defined fusion milestones to proof of the scientific feasibility, of laser fusion with the Shiva Nova system. Concurrently, those key technical areas, such as advanced lasers, which are required to progress beyond proof of feasibility, are being studied. We have identified and quantified the opportunities and key technical issues in military applications, such as weapons effects simulations, and in civilian applications, such as central-station electric power production. We summarize the current status and future plans for the laser fusion program at LLL, emphasizing the civilian applications of laser fusion

  18. Physics of semiconductor lasers

    Mroziewicz, B; Nakwaski, W

    2013-01-01

    Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor l

  19. Principles of laser dynamics

    Khanin, YI

    1995-01-01

    This monograph summarizes major achievements in laser dynamics over the past three decades. The book begins with two introductory Chapters. Chapter 1 offers general considerations on quantum oscillators, formulates the requirements for the laser key elements and shows how these requirements are met in different laser systems. The second Chapter proposes the mathematical models used in semiclassical laser theory, discusses the approximations and simplifications in particular cases, and specifies the range of applicability of these models. In Chapters 3-5 attention is given primarily to the stea

  20. Laser transmitter system

    Dye, R.A.

    1975-01-01

    A laser transmitter system is disclosed which utilizes mechanical energy for generating an output pulse. The laser system includes a current developing device such as a piezoelectric crystal which charges a storage device such as a capacitor in response to a mechanical input signal. The capacitor is coupled to a switching device, such as a silicon controlled rectifier (SCR). The switching device is coupled to a laser transmitter such as a GaAs laser diode, which provides an output signal in response to the capacitor being discharged

  1. Laser in urology

    Breisland, H.O.

    1991-01-01

    The neodymium YAG laser is particularly suited for endoscopic urologic surgery because the YAG laser light can be conducted in flexible fibers. Superficial bladder tumours can be treated under local anaesthesia in the outpatient department. The frequency of local recurrences is low, significantly lower than after electrosection or electrocoagulation. Selected cases of T2-muscle invasive bladder tumours can be cured with laser coagulation applied subsequently to transurethral resection. Combined treatment with electrosection and laser coagulation of localized prostatic cancer is a promising method which compares favourably with results obtained by other treatment modalities. Tumours in the upper urinary tract can be laser-treated through ureteroscopes or nephroscopes, but the treatment should be limited to low stage, low grade tumours. Laser is the treatment of choice for intraurethral condylomatas. Laser treatment of penil carcinoma gives excellent cosmetic and functional results and few local recurrences. Laser lithotripsy is a new technique for treatment of ureteric stones and photodynamic laser therapy is a promising tecnique for treatment of carcinoma in situ in the bladder empithelium. However, neither of these techniques are available for clinical use in Norway as yet. 17 refs., 3 figs., 1 tabs

  2. Tunable Microfluidic Dye Laser

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  3. Trends in laser micromachining

    Gaebler, Frank; van Nunen, Joris; Held, Andrew

    2016-03-01

    Laser Micromachining is well established in industry. Depending on the application lasers with pulse length from μseconds to femtoseconds and wavelengths from 1064nm and its harmonics up to 5μm or 10.6μm are used. Ultrafast laser machining using pulses with pico or femtosecond duration pulses is gaining traction, as it offers very precise processing of materials with low thermal impact. Large-scale industrial ultrafast laser applications show that the market can be divided into various sub segments. One set of applications demand low power around 10W, compact footprint and are extremely sensitive to the laser price whilst still demanding 10ps or shorter laser pulses. A second set of applications are very power hungry and only become economically feasible for large scale deployments at power levels in the 100+W class. There is also a growing demand for applications requiring fs-laser pulses. In our presentation we would like to describe these sub segments by using selected applications from the automotive and electronics industry e.g. drilling of gas/diesel injection nozzles, dicing of LED substrates. We close the presentation with an outlook to micromachining applications e.g. glass cutting and foil processing with unique new CO lasers emitting 5μm laser wavelength.

  4. Scanning Color Laser Microscope

    Awamura, D.; Ode, T.; Yonezawa, M.

    1988-01-01

    A confocal color laser microscope which utilizes a three color laser light source (Red: He-Ne, Green: Ar, Blue: Ar) has been developed and is finding useful applications in the semiconductor field. The color laser microscope, when compared to a conventional microscope, offers superior color separation, higher resolution, and sharper contrast. Recently some new functions including a Focus Scan Memory, a Surface Profile Measurement System, a Critical Dimension Measurement system (CD) and an Optical Beam Induced Current Function (OBIC) have been developed for the color laser microscope. This paper will discuss these new features.

  5. High Power Vanadate lasers

    Strauss

    2006-07-01

    Full Text Available stream_source_info Strauss1_2006.pdf.txt stream_content_type text/plain stream_size 3151 Content-Encoding UTF-8 stream_name Strauss1_2006.pdf.txt Content-Type text/plain; charset=UTF-8 Laser Research Institute... University of Stellenbosch www.laser-research.co.za High Power Vanadate lasers H.J.Strauss, Dr. C. Bollig, R.C. Botha, Prof. H.M. von Bergmann, Dr. J.P. Burger Aims 1) To develop new techniques to mount laser crystals, 2) compare the lasing properties...

  6. Laser adaptive holographic hydrophone

    Romashko, R V; Kulchin, Yu N; Bezruk, M N; Ermolaev, S A [Institute of Automation and Control Processes, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok (Russian Federation)

    2016-03-31

    A new type of a laser hydrophone based on dynamic holograms, formed in a photorefractive crystal, is proposed and studied. It is shown that the use of dynamic holograms makes it unnecessary to use complex optical schemes and systems for electronic stabilisation of the interferometer operating point. This essentially simplifies the scheme of the laser hydrophone preserving its high sensitivity, which offers the possibility to use it under a strong variation of the environment parameters. The laser adaptive holographic hydrophone implemented at present possesses the sensitivity at a level of 3.3 mV Pa{sup -1} in the frequency range from 1 to 30 kHz. (laser hydrophones)

  7. Introduction to laser technology

    Hitz, C Breck; Hecht, Jeff

    2012-01-01

    The only introductory text on the market today that explains the underlying physics and engineering applicable to all lasersAlthough lasers are becoming increasingly important in our high-tech environment, many of the technicians and engineers who install, operate, and maintain them have had little, if any, formal training in the field of electro-optics. This can result in less efficient usage of these important tools. Introduction to Laser Technology, Fourth Edition provides readers with a good understanding of what a laser is and what it can and cannot do. The book explains what types of las.

  8. Laser-induced interactions

    Green, W.R.

    1979-01-01

    This dissertation discusses some of the new ways that lasers can be used to control the energy flow in a medium. Experimental and theoretical considerations of the laser-induced collision are discussed. The laser-induced collision is a process in which a laser is used to selectively transfer energy from a state in one atomic or molecular species to another state in a different species. The first experimental demonstration of this process is described, along with later experiments in which lasers were used to create collisional cross sections as large as 10 - 13 cm 2 . Laser-induced collisions utilizing both a dipole-dipole interaction and dipole-quadrupole interaction have been experimentally demonstrated. The theoretical aspects of other related processes such as laser-induced spin-exchange, collision induced Raman emission, and laser-induced charge transfer are discussed. Experimental systems that could be used to demonstrate these various processes are presented. An experiment which produced an inversion of the resonance line of an ion by optical pumping of the neutral atom is described. This type of scheme has been proposed as a possible method for constructing VUV and x-ray lasers

  9. Jet laser ion source

    Dem'yanov, A.V.; Sidorov, S.V.

    1994-01-01

    External laser injector of multicharged ions (MCI) is developed in which wide-aperture aberration-free wire gauze spherical shape electrodes are applied for effective MCI extraction from laser plasma and beam focusing. Axial plasma compression by solenoid magnetic field is used to reduce ion losses due to transverse movement of the scattering laser plasma. Transverse magnetic field created by another solenoid facilitates the effective laser plasma braking and consequently, leads to the narrowing of energy spectrum of plasma ions and its shift towards lower energies. 2 refs.; 3 figs

  10. Free electron laser

    Ortega, J.M.; Billardon, M.

    1986-01-01

    Operation principle of a laser and an oscillator are recalled together with the klystron one. In the free electron laser, electrons go through an undulator or an optical klystron. Principles of the last one are given. The two distinct ways of producing coherent radiation with an undulator and an optical klystron are presented. The first one is the use of the free electron laser, the second is to make use of the spontaneous emission generation (harmonics generation). The different current types of free electron lasers are presented (Stanford, Los Alamos, Aco at Orsay). Prospects and applications are given in conclusion [fr

  11. Laser cooling of solids

    Petrushkin, S V

    2009-01-01

    Laser cooling is an important emerging technology in such areas as the cooling of semiconductors. The book examines and suggests solutions for a range of problems in the development of miniature solid-state laser refrigerators, self-cooling solid-state lasers and optical echo-processors. It begins by looking at the basic theory of laser cooling before considering such topics as self-cooling of active elements of solid-state lasers, laser cooling of solid-state information media of optical echo-processors, and problems of cooling solid-state quantum processors. Laser Cooling of Solids is an important contribution to the development of compact laser-powered cryogenic refrigerators, both for the academic community and those in the microelectronics and other industries. Provides a timely review of this promising field of research and discusses the fundamentals and theory of laser cooling Particular attention is given to the physics of cooling processes and the mathematical description of these processes Reviews p...

  12. Laser beam diagnostics for kilowatt power pulsed YAG laser

    Liu, Yi; Leong, Keng H.

    1992-01-01

    There is a growing need for high power YAG laser beam diagnostics with the recent introduction of such lasers in laser material processing. In this paper, we will describe the use of a commercially available laser beam analyzer (Prometec) to profile the laser beam from a 1600 W pulsed Nd:YAG laser that has a 1 mm fiber optic beam delivery system. The selection of laser pulse frequency and pulse width for the measurement is discussed. Laser beam propagation parameters by various optical components such as fibers and lenses can be determined from measurements using this device. The importance of such measurements will be discussed

  13. Laser Program annual report 1987

    O' Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W. (eds.)

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies.

  14. Laser Program annual report 1987

    O'Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W.

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies

  15. Temperature controller of semiconductor laser

    Matoušek, Vít; Číp, Ondřej

    2003-01-01

    Roč. 73, č. 3 (2003), s. 10 - 12 ISSN 0928-5008 Institutional research plan: CEZ:AV0Z2065902 Keywords : temperature controller * semiconductor laser * laser diode Subject RIV: BH - Optics, Masers, Lasers

  16. LASERS: A cryogenic slab CO laser

    Ionin, Andrei A.; Kozlov, A. Yu; Seleznev, L. V.; Sinitsyn, D. V.

    2009-03-01

    A compact capacitive transverse RF-discharge-pumped slab CO laser with cryogenically cooled electrodes, which operates both in the cw and repetitively pulsed regimes, is fabricated. The laser operation is studied in the free running multifrequency regime at the vibrational - rotational transitions of the fundamental (V + 1 → V) vibrational bands of the CO molecule in the spectral region from 5.1 to 5.4 μm. Optimal operation conditions (gas mixture composition and pressure, RF pump parameters) are determined. It is shown that only gas mixtures with a high content of oxygen (up to 20% with respect to the concentration of CO molecules) can be used as an active medium of this laser. It is demonstrated that repetitively pulsed pumping is more efficient compared to cw pumping. In this case, quasi-cw lasing regime can be obtained. The maximum average output power of ~12 W was obtained for this laser operating on fundamental bands and its efficiency achieved ~14 %. The frequency-selective operation regime of the slab RF-discharge-pumped CO laser was realised at ~ 100 laser lines in the spectral region from 5.0 to 6.5 μm with the average output power of up to several tens of milliwatts in each line. Lasing at the transitions of the first vibrational overtone (V + 2 → V) of the CO molecule is obtained in the spectral region from 2.5 to 3.9 μm. The average output power of the overtone laser achieved 0.3 W. All the results were obtained without the forced gas mixture exchange in the discharge chamber. Under fixed experimental conditions, repetitively pulsed lasing (with fluctuations of the output characteristics no more than ±10 %) was stable for more than an hour.

  17. Grid laser with modified pro re nata injection of bevacizumab and ranibizumab in macular edema due to branch retinal vein occlusion: MARVEL report no 2

    Narayanan R

    2016-06-01

    Full Text Available Raja Narayanan,1 Bhavik Panchal,1 Michael W Stewart,2 Taraprasad Das,1 Jay Chhablani,1 Subhadra Jalali,1 Mohd Hasnat Ali3 On behalf of MARVEL study group 1Smt. Kanuri Santhamma Centre for Vitreo Retinal Diseases, L V Prasad Eye Institute, Hyderabad, India; 2Department of Ophthalmology, Mayo Clinic, Jacksonville, FL, USA; 3Department of Biostatistics, L V Prasad Eye Institute, Hyderabad, India Purpose: The purpose of this study was to prospectively study the efficacy of grid laser combined with intravitreal bevacizumab or ranibizumab in eyes with macular edema due to branch retinal vein occlusion.Patients and methods: Treatment-naïve eyes were enrolled to receive injections of ranibizumab or bevacizumab. During the first 6 months, patients were evaluated monthly and injected if the best-corrected visual acuity changed by five or more letters or fluid was noted on spectral domain optical coherence tomography (OCT; during the next 6 months, patients were evaluated bimonthly and injected only if the best-corrected visual acuity decreased by five or more letters with the associated fluid. Grid laser photocoagulation was performed if there was fluid on OCT and was repeated if patients were eligible after a minimum interval of 3 months.Results: The mean numbers of ranibizumab and bevacizumab injections were, respectively, 3.2±1.5 and 3.0±1.4 in the first 6 months and 0.3±0.6 and 0.3±0.6 in the last 6 months. ­Moreover, 55/75 (73.33% participants did not receive any injections in the last 6 months. The mean reductions in central retinal thickness at 12 months were 165.67 µm (P<0.001; 95% ­confidence interval -221.50 to -135.0 in the ranibizumab group and 184.78 µm (P<0.001; 95% confidence interval -246.49 to -140.0 in the bevacizumab group (P=0.079. More patients in the bevacizumab group compared to those in the ranibizumab group required rescue laser at 12 months (20 vs eleven; P=0.06.Conclusion: Bimonthly evaluations after month 6

  18. Power balancing of multibeam laser fusion lasers

    Seka, W.; Morse, S.; Letzring, S.; Kremens, R.; Kessler, T.J.; Jaanimagi, P.; Keck, R.; Verdon, C.; Brown, D.

    1989-01-01

    The success of laser fusion depends to a good degree on the ability to compress the target to very high densities of ≥1000 times liquid DT. To achieve such compressions require that the irradiation nonuniformity must not exceed ∼1% rms over the whole time of the compression, particularly during the early phases of irradiation. The stringent requirements for the irradiation uniformity for laser fusion have been known for quite some time but until recently the energy balance was mistakenly equated to power balance. The authors describe their effort on energy balance and irradiation patterns on the target. They significantly improved the laser performance with respect to overall intensity distributions on target including the implementation of distributed (random) phase plates in each high power beam. However, the slightly varying performance of the third harmonic conversion crystals in the twenty-four beams of their laser system was generally compensated for by appropriately adjusted 1.054μm input laser energy. Computational analysis of the results of the recent high density campaign are shown

  19. Laser Stabilization with Laser Cooled Strontium

    Christensen, Bjarke Takashi Røjle

    The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting the nonli......The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting...... the nonlinear effects from coupling of an optical cavity to laser cooled atoms having a narrow transition linewidth. Here, we have realized such a system where a thermal sample of laser cooled strontium-88 atoms are coupled to an optical cavity. The strontium-88 atoms were probed on the narrow 1S0-3P1 inter......-combination line at 689 nm in a strongly saturated regime. The dynamics of the atomic induced phase shift and absorption of the probe light were experimentally studied in details with the purpose of applications to laser stabilization. The atomic sample temperature was in the mK range which brought this system out...

  20. High-power pulsed lasers

    Holzrichter, J.F.

    1980-01-01

    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization

  1. Laser safety tools and training

    Barat, Ken

    2008-01-01

    Lasers perform many unique functions in a plethora of applications, but there are many inherent risks with this continually burgeoning technology. Laser Safety: Tools and Training presents simple, effective ways for users in a variety of facilities to evaluate the hazards of any laser procedure and ensure they are following documented laser safety standards.Designed for use as either a stand-alone volume or a supplement to Laser Safety Management, this text includes fundamental laser and laser safety information and critical laser use information rarely found in a single source. The first lase

  2. Laser biostimulation in pediatrics

    Utz, Irina A.; Lagutina, L. E.; Tuchin, Valery V.

    1995-01-01

    In the present paper the method and apparatus for percutaneous laser irradiation of blood (PLIB) in vessels (veins) are described. Results of clinical investigations of biostimulating effects under PLIB by red laser light (633 nm) in Cubiti and Saphena Magna veins are presented.

  3. Metallic DFB lasers

    Marell, M.J.H.; Nötzel, R.; Smit, M.K.; Hill, M.T.; Pozo, J.; Mortensen, M.; Urbach, P.; Leijtens, X.; Yousefi, M.

    2010-01-01

    In this paper we present our latest results on the design, fabrication and characterization of metal coated DFB lasers. These devices are based on a specialform of the metal-insulator-metal waveguides, which support plasmon gap modes. The distributed feedback provides control over the laser ~

  4. Laser processing of materials

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    The initial foundation of laser theory was laid by Einstein [11]. ..... general definition and scope of the processes as understood in conventional practice, but is ..... [54]. Laser welding of Ti-alloys. Welding. 2001 TiNi shape memory alloys. CW–CO2. Study corrosion, mechanical and shape memory properties of weldments.

  5. Microfluidic Dye Lasers

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten

    2006-01-01

    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  6. Laser trabeculotomy versus trabeculoplasty

    Ticho, U.; Frucht, J.

    1984-01-01

    Although laser trabeculotomy has failed in glaucoma management, the laser trabeculoplasty (LTP) procedure has proved to be helpful. LTP was found to improve glaucoma control in 80-90% of open angle glaucoma patients, and less in secondary glaucoma and low tension glaucoma (50%). The procedure is more successful in dark iris eyes and complications are transient. (Auth.)

  7. 5. Laser plasma interaction

    Labaune, C.; Fuchs, J.; Bandulet, H.

    2002-01-01

    Imprint elimination, smoothing and preheat control are considerable problems in inertial fusion and their possible solution can be achieved by using low-density porous materials as a buffer in target design. The articles gathered in this document present various aspects of the laser-plasma interaction, among which we have noticed: -) numerical algorithmic improvements of the Vlasov solver toward the simulation of the laser-plasma interaction are proposed, -) the dependence of radiation temperatures and X-ray conversion efficiencies of hohlraum on the target structures and laser irradiation conditions are investigated, -) a study of laser interaction with ultra low-density (0,5 - 20 mg/cm 3 ) porous media analyzing backscattered light at incident laser frequency ω 0 and its harmonics 3*ω 0 /2 and 2*ω 0 is presented, -) investigations of laser interaction with solid targets and crater formation are carried out with the objective to determine the ablation loading efficiency, -) a self organization in an intense laser-driven plasma and the measure of the relative degree of order of the states in an open system based on the S-theorem are investigated, and -) the existence and stability of electromagnetic solitons generated in a relativistic interaction of an intense laser light with uniform under-dense cold plasma are studied

  8. Laser Interference Lithography

    van Wolferen, Hendricus A.G.M.; Abelmann, Leon; Hennessy, Theodore C.

    In this chapter we explain how submicron gratings can be prepared by Laser Interference Lithography (LIL). In this maskless lithography technique, the standing wave pattern that exists at the intersection of two coherent laser beams is used to expose a photosensitive layer. We show how to build the

  9. Levitated droplet dye laser

    Azzouz, H.; Alkafadiji, L.; Balslev, Søren

    2006-01-01

    a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating...

  10. Laser induced energy transfer

    Falcone, R.W.

    1979-01-01

    Two related methods of rapidly transferring stored energy from one excited chemical species to another are described. The first of these, called a laser induced collision, involves a reaction in which the energy balance is met by photons from an intense laser beam. A collision cross section of ca 10 - 17 cm 2 was induced in an experiment which demonstrated the predicted dependence of the cross section on wavelength and power density of the applied laser. A second type of laser induced energy transfer involves the inelastic scattering of laser radiation from energetically excited atoms, and subsequent absorption of the scattered light by a second species. The technique of producing the light, ''anti-Stokes Raman'' scattering of visible and infrared wavelength laser photons, is shown to be an efficient source of narrow bandwidth, high brightness, tunable radiation at vacuum ultraviolet wavelengths by using it to excite a rare gas transition at 583.7 A. In addition, this light source was used to make the first measurement of the isotopic shift of the helium metastable level at 601 A. Applications in laser controlled chemistry and spectroscopy, and proposals for new types of lasers using these two energy transfer methods are discussed

  11. Coaxial short pulsed laser

    Nelson, M.A.; Davies, T.J.

    1975-08-01

    This invention relates to a laser system of rugged design suitable for use in a field environment. The laser itself is of coaxial design with a solid potting material filling the space between components. A reservoir is employed to provide a gas lasing medium between an electrode pair, each of which is connected to one of the coaxial conductors. (auth)

  12. LASER EN LARYNGOLOGIE

    9 mai 2013 ... permettant selon les besoins, coagulation, section ou vaporisation. ... tés par laser au service d'ORL et de chirurgie cervico-. LASER EN .... nose était de siège glottique pur à type de palmure dans. 3 cas et supra glottique ...

  13. Lasers in nuclear physics

    Inamura, T.T.

    1988-01-01

    The hyperfine interaction has been reviewed from a point of view of nuclear physics. Recent progress of nuclear spectroscopy with lasers is presented as one of laser studies of fundamental physics currently pursued in Japan. Especially, the hyperfine anomaly is discussed in connection with the origin of nuclear magnetism. (author)

  14. for aqueous dye lasers

    2014-02-12

    Feb 12, 2014 ... inclusion complex of RhB with the container molecule cucurbit[7]uril (CB[7]). Keywords. Temperature-dependent fluorescence; Rhodamine B; cucurbit[7]uril; host–guest complex; dye laser. PACS Nos 36.20.kd; 83.60.pq; 87.64.kv. 1. Introduction. Rhodamine B (RhB) is an efficient and photostable laser dye ...

  15. Electrodeless excimer laser

    Lisi, N.

    2001-01-01

    In this paper it is proposed how to build an excimer laser based on an electrodeless discharge (or Dielectric Barrier Discharge). Such laser could operate with a low energy per pulse ( 2 excimer molecule, whose emission wavelength in the VUV range (157 nm) at high reprate is particularly interesting in the micro-lithography field [it

  16. Auricular Acupuncture with Laser

    Bahr, Frank

    2013-01-01

    Auricular acupuncture is a method which has been successfully used in various fields of medicine especially in the treatment of pain relief. The introduction of lasers especially low-level lasers into medicine brought besides the already existing stimulation with needles and electricity an additional technique to auricular acupuncture. This literature research looks at the historical background, the development and the anatomical and neurological aspects of auricular acupuncture in general and auricular laser acupuncture in detail. Preliminary scientific findings on auricular acupuncture with laser have been described in detail and discussed critically in this review article. The results of the studies have shown evidence of the effect of auricular laser acupuncture. However, a comparison of these studies was impossible due to their different study designs. The most important technical as well as study parameters were described in detail in order to give more sufficient evidence and to improve the quality of future studies. PMID:23935695

  17. Powering laser diode systems

    Trestman, Grigoriy A

    2017-01-01

    This Tutorial Text discusses the competent design and skilled use of laser diode drivers (LDDs) and power supplies (PSs) for the electrical components of laser diode systems. It is intended to help power-electronic design engineers during the initial design stages: the choice of the best PS topology, the calculation of parameters and components of the PS circuit, and the computer simulation of the circuit. Readers who use laser diode systems for research, production, and other purposes will also benefit. The book will help readers avoid errors when creating laser systems from ready-made blocks, as well as understand the nature of the "mystical failures" of laser diodes (and possibly prevent them).

  18. Laser Beam Focus Analyser

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove

    2007-01-01

    the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating......The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  19. Introducing the yellow laser

    Lincoln, James

    2018-02-01

    The author has acquired a yellow laser with the specific wavelength of 589 nm. Because this is the first time such a laser has been discussed in this journal, I feel it is appropriate to provide a discussion of its function and capabilities. Normal laser safety should be employed, such as not pointing it into eyes or at people, and using eye protection for the young and inexperienced. It is important to note that 589 nm is the same wavelength as the Sodium-D line (doublet). This allows for the laser to serve as a replacement for sodium lamps, and, considering its rather high price, this added value should be balanced against its cost. What follows is a list of activities that showcase the yellow laser's unique promise as an engaging piece of technology that can be used in the teaching of physics.

  20. Regenerative similariton laser

    Thibault North

    2016-05-01

    Full Text Available Self-pulsating lasers based on cascaded reshaping and reamplification (2R are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration.

  1. Femtosecond Laser Filamentation

    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 ...

  2. NASA Space Laser Technology

    Krainak, Michael A.

    2015-01-01

    Over the next two decades, the number of space based laser missions for mapping, spectroscopy, remote sensing and other scientific investigations will increase several fold. The demand for high wall-plug efficiency, low noise, narrow linewidth laser systems to meet different systems requirements that can reliably operate over the life of a mission will be high. The general trends will be for spatial quality very close to the diffraction limit, improved spectral performance, increased wall-plug efficiency and multi-beam processing. Improved spectral performance will include narrower spectral width (very near the transform limit), increased wavelength stability and or tuning (depending on application) and lasers reaching a wider range of wavelengths stretching into the mid-infrared and the near ultraviolet. We are actively developing high efficiency laser transmitter and high-sensitivity laser receiver systems that are suitable for spaceborne applications.

  3. Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

    Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)

    2000-04-01

    Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

  4. Laser Safety Inspection Criteria

    Barat, K.

    2005-01-01

    A responsibility of the Laser Safety Officer (LSO) is to perform laser audits. The American National Standard Z136.1 Safe Use of Lasers references this requirement through several sections. One such reference is Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''. The composition, frequency and rigor of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms It is common for audit findings from one inspector or inspection to the next to vary even when reviewing the same material. How often has one heard a comment, ''well this area has been inspected several times over the years and no one ever said this or that was a problem before''. A great number of audit items, and therefore findings, are subjective because they are based on the experience and interest of the auditor to particular items on the checklist. Beam block usage, to one set of eyes might be completely adequate, while to another, inadequate. In order to provide consistency, the Laser Safety Office of the National Ignition Facility Directorate has established criteria for a number of items found on the typical laser safety audit form. The criteria are distributed to laser users. It serves two broad purposes; first, it gives the user an expectation of what will be reviewed by an auditor. Second, it is an opportunity to explain audit items to the laser user and thus the reasons for some of these items, such as labelling of beam blocks

  5. Laser requirements for a laser fusion energy power plant

    Stephen; E.Bodner; Andrew; J.Schmitt; John; D.Sethian

    2013-01-01

    We will review some of the requirements for a laser that would be used with a laser fusion energy power plant, including frequency, spatial beam smoothing, bandwidth, temporal pulse shaping, efficiency, repetition rate, and reliability. The lowest risk and optimum approach uses a krypton fluoride gas laser. A diode-pumped solid-state laser is a possible contender.

  6. Measurements of laser parameters for the Shiva laser fusion facility

    Ozarski, R.G.

    1979-01-01

    Large laser systems require numerous laser diagnostics to provide configuration, performance and maintenance data to permit efficient operation. The following diagnostics for a large laser system named Shiva are discussed: (1) description of Shiva laser system, (2) what measurements are desired and or required and why, (3) what measurement techniques and packages are employed and a brief description of the operating principles of the sensors employed, and (4) the laser diagnostic data acquisition and display system

  7. LASER PROCESSING ON SINGLE CRYSTALS BY UV PULSE LASER

    龍見, 雅美; 佐々木, 徹; 高山, 恭宜

    2009-01-01

    Laser processing by using UV pulsed laser was carried out on single crystal such as sapphire and diamond in order to understand the fundamental laser processing on single crystal. The absorption edges of diamond and sapphire are longer and shorter than the wave length of UV laser, respectively. The processed regions by laser with near threshold power of processing show quite different state in each crystal.

  8. Laser diode technology and applications

    Figueroa, L.

    1989-01-01

    This book covers a wide range of semiconductor laser technology, from new laser structures and laser design to applications in communications, remote sensing, and optoelectronics. The authors report on new laser diode physics and applications and present a survey of the state of the art as well as progress in new developments

  9. 1982 laser program annual report

    Hendricks, C.D.; Grow, G.R. (eds.)

    1983-08-01

    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications. (MOW)

  10. Fractional laser skin resurfacing.

    Alexiades-Armenakas, Macrene R; Dover, Jeffrey S; Arndt, Kenneth A

    2012-11-01

    Laser skin resurfacing (LSR) has evolved over the past 2 decades from traditional ablative to fractional nonablative and fractional ablative resurfacing. Traditional ablative LSR was highly effective in reducing rhytides, photoaging, and acne scarring but was associated with significant side effects and complications. In contrast, nonablative LSR was very safe but failed to deliver consistent clinical improvement. Fractional LSR has achieved the middle ground; it combined the efficacy of traditional LSR with the safety of nonablative modalities. The first fractional laser was a nonablative erbium-doped yttrium aluminum garnet (Er:YAG) laser that produced microscopic columns of thermal injury in the epidermis and upper dermis. Heralding an entirely new concept of laser energy delivery, it delivered the laser beam in microarrays. It resulted in microscopic columns of treated tissue and intervening areas of untreated skin, which yielded rapid reepithelialization. Fractional delivery was quickly applied to ablative wavelengths such as carbon dioxide, Er:YAG, and yttrium scandium gallium garnet (2,790 nm), providing more significant clinical outcomes. Adjustable laser parameters, including power, pitch, dwell time, and spot density, allowed for precise determination of percent surface area, affected penetration depth, and clinical recovery time and efficacy. Fractional LSR has been a significant advance to the laser field, striking the balance between safety and efficacy.

  11. The argon excimer laser

    Wrobel, W.G.

    1981-02-01

    The electron-beam-pumped argon eximer laser is investigated and tuned for the first time. The electron beam is generated by means of an improved coaxial field emmision diode in which argon gas is excited with power densities of 0.3 GW/cm 3 for 18 ns. The processes in the excited gas of 20 to 65 bar are described in the context of a kinetic model as a sequence of stationary states. Investigations of the amplified spontaneous emission (superfluorescence) confirm the predictions of this model. Only the absorption due to the excited Ar atoms is anomalously high. Reproducible operation of the argon eximer laser was achieved in a wide pressure range with various resonator arrangements. The wavelength of this shortest wavelength of this shortest wavelength excimer laser is 126 nm, the laser line width approx. 1.7 nm, the pulse length 7 to 13 ns, and the laser power 250 kW. The laser emission is tuned from 123.2 nm to 128.4 nm by two different methods (diffraction grating and prism). This tunable laser is thus the one with the shortest wavelength at present. Its line width is 0.25 to 0.4 nm, and the power ue 1.7 kW. (orig.)

  12. Laser wakefield acceleration

    Esarey, E.; Ting, A.; Sprangle, P.

    1989-01-01

    The laser wakefield accelerator (LWFA) is a novel plasma based electron acceleration scheme which utilizes a relativistic optical guiding mechanism for laser pulse propagation. In the LWFA, a short, high power, single frequency laser pulse is propagated through a plasma. As the laser pulse propagates, its radial and axial ponderomotive forces nonresonantly generate large amplitude plasma waves (wakefields) with a phase velocity equal to the group velocity of the pulse. A properly phased electron bunch may then be accelerated by the axial wakefield and focused by the transverse wakefield. Optical guiding of the laser pulse in the plasma is necessary in order to achieve high energies in a single stage of acceleration. At sufficiently high laser powers, optical guiding may be achieved through relativistic effects associated with the plasma electrons. Preliminary analysis indicates that this scheme may overcome some of the difficulties present in the plasma beat wave accelerator and in the plasma wakefield accelerator. Analytical and numerical calculations are presented which study both laser pulse propagation within a plasma as well as the subsequent generation of large amplitude plasma waves. In addition, the generation of large amplitude plasma waves in regimes where the plasma waves become highly nonlinear is examined

  13. Excimer laser decontamination

    Sentis, Marc L.; Delaporte, Philippe C.; Marine, Wladimir; Uteza, Olivier P.

    2000-04-01

    The application of excimer laser ablation process to the decontamination of radioactive surfaces is discussed. This technology is very attractive because it allows to efficiently remove the contaminated particles without secondary waste production. To demonstrate the capability of such technology to efficiently decontaminate large area, we studied and developed a prototype which include a XeCl laser, an optical fiber delivery system and an ablated particles collection cell. The main physical processes taking place during UV laser ablation will be explained. The influence of laser wavelength, pulse duration and absorption coefficient of material will be discussed. Special studies have been performed to understand the processes which limit the transmission of high average power excimer laser through optical fiber, and to determine the laser conditions to optimize the value of this transmission. An in-situ spectroscopic analysis of laser ablation plasma allows the real time control of the decontamination. The results obtained for painting or metallic oxides removal from stainless steel surfaces will be presented.

  14. Color Laser Microscope

    Awamura, D.; Ode, T.; Yonezawa, M.

    1987-04-01

    A color laser microscope utilizing a new color laser imaging system has been developed for the visual inspection of semiconductors. The light source, produced by three lasers (Red; He-Ne, Green; Ar, Blue; He-Cd), is deflected horizontally by an AOD (Acoustic Optical Deflector) and vertically by a vibration mirror. The laser beam is focused in a small spot which is scanned over the sample at high speed. The light reflected back from the sample is reformed to contain linear information by returning to the original vibration mirror. The linear light is guided to the CCD image sensor where it is converted into a video signal. Individual CCD image sensors are used for each of the three R, G, or B color image signals. The confocal optical system with its laser light source yields a color TV monitor image with no flaring and a much sharper resolution than that of the conventional optical microscope. The AOD makes possible a high speed laser scan and a NTSC or PAL TV video signal is produced in real time without any video memory. Since the light source is composed of R, G, and B laser beams, color separation superior to that of white light illumination is achieved. Because of the photometric linearity of the image detector, the R, G, and B outputs of the system are most suitably used for hue analysis. The CCD linear image sensors in the optical system produce no geometrical distortion, and good color registration is available principally. The output signal can be used for high accuracy line width measuring. The many features of the color laser microscope make it ideally suited for the visual inspection of semiconductor processing. A number of these systems have already been installed in such a capacity. The Color Laser Microscope can also be a very useful tool for the fields of material engineering and biotechnology.

  15. Dye laser principles with applications

    Duarte, Frank J; Liao, Peter F; Kelley, Paul

    1990-01-01

    A tutorial introduction to the field of dye lasers, Dye Laser Principles also serves as an up-to-date overview for those using dye lasers as research and industrial tools. A number of the issues discussed in this book are pertinent not only to dye lasers but also to lasers in general. Most of the chapters in the book contain problem sets that expand on the material covered in the chapter.Key Features* Dye lasers are among the most versatile and successful laser sources currently available in use Offering both pulsed and continuous-wave operation and tunable from the near ultraviole

  16. Temperature stabilization of injection lasers

    Albanese, A.

    1987-01-01

    Apparatus which stabilizes the temperature, and thereby the output wavelength, of an injection laser. Means monitor the laser terminal voltage across a laser and derive a voltage therefrom which is proportional to the junction voltage of the laser. Means compares the voltage to a reference value from source and a temperature controller adjusts the laser temperature in response to the results of the comparison. Further embodiments of the present invention vary the output wavelength of the laser by varying the reference value from source against which the laser junction voltage is compared. (author)

  17. Latest development of laser cutting

    Wetzig, Andreas; Herwig, Patrick; Hauptmann, Jan; Goppold, Cindy; Baumann, Robert; Fürst, Andreas; Rose, Michael; Pinder, Thomas; Mahrle, Achim; Beyer, Eckhard

    2016-01-01

    Laser cutting was one of the first applications of laser material processing. Today, laser cutting is the most widespread application among laser material processing besides laser marking. Meanwhile, nearly each material can be cut by means of a laser, in particular since ultra short pulse lasers are available in the power range of up to 100 W. The to be cut material can come with thicknesses from a few microns till tens of millimeters as flat stock or as free form shapes. The paper will conc...

  18. Color speckle in laser displays

    Kuroda, Kazuo

    2015-07-01

    At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

  19. Teradiode's high brightness semiconductor lasers

    Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

    2016-03-01

    TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

  20. Organic solid-state lasers

    Forget, Sébastien

    2013-01-01

    Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.

  1. Laser Hazards Bibliography

    1989-10-31

    light on mandibular fracture healing, Stomatologiia, 57(5): 5-9 (1978). 42 Laser Hazards Bibliography 177. Van Gemert, M.J.C., Schets, G.A.C.M., Bishop...U., Laser-coagulation of ruptured fixation suture after lens implantation, J Am Intraocul Implant Soc, 4(2): 54 (1978). 49. Federman, J. L., Ando, F...laser in pediatric surgery, J Ped Surg, 3: 263-270 (April 1968). 82. Hennessy, R. T., and Leibowitz, H., Subjective measurement of accommodation with

  2. Optimising laser tattoo removal

    Kabir Sardana

    2015-01-01

    Full Text Available Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal.

  3. Ultrashort Laser Pulse Phenomena

    Diels, Jean-Claude

    2006-01-01

    Ultrashort Laser Pulse Phenomena, 2e serves as an introduction to the phenomena of ultra short laser pulses and describes how this technology can be used to examine problems in areas such as electromagnetism, optics, and quantum mechanics. Ultrashort Laser Pulse Phenomena combines theoretical backgrounds and experimental techniques and will serve as a manual on designing and constructing femtosecond (""faster than electronics"") systems or experiments from scratch. Beyond the simple optical system, the various sources of ultrashort pulses are presented, again with emphasis on the basic

  4. Laser-driven accelerators

    Anon.

    1982-01-01

    Several devices for using laser fields have been proposed and they can be classified in three broad categories - 'far-field' accelerators (such as the principle of inverse free electron lasers), 'media' accelerators (which, for example, use the inverse Cherenkov effect or laser-controlled plasma waves), and 'near-field' accelerators (using a loaded guiding structure such as cavities or gratings). These different approaches come from the fact that a particle cannot be accelerated by the absorption of single photons (because of momentum conservation) and thus some other element has to intervene. (orig./HSI).

  5. Regenerative laser system

    Biancardi, F.R.; Landerman, A.; Melikian, G.

    1975-01-01

    Regenerative apparatus for exhausting the working medium from the optical cavity of a laser and for supplying preheated diluent to the reaction chamber of a laser is disclosed. In an aftercooler thermal energy is exchanged between the working medium exhausted from the optical cavity and a cryogenic coolant which is subsequently utilized as the motive fluid for an ejector and as a diluent in the production of laser gas. Highly toxic and corrosive gases are condensed out of the working medium as the cryogenic coolant is evaporated and superheated. A preheater transfers additional heat to the diluent before the diluent enters the reaction chamber. (U.S.)

  6. Tunable excimer lasers

    Sze, R.C.

    1990-01-01

    The wide bandwidth nature of the rare-gas halide excimer transitions allow reasonable tuning of the laser oscillation wavelength that makes it useful for a number of applications. At the same time this wide bandwidth makes narrow band operation difficult and special techniques are needed to insure narrow frequency lasing as well as absolute frequency resettability. The author discusses briefly some of the classical frequency narrowing techniques and then goes on to some recent work that require lasers of special frequency characteristics for special applications including KrF laser fusion

  7. Diatomic gasdynamic lasers.

    Mckenzie, R. L.

    1972-01-01

    Predictions from a numerical model of the vibrational relaxation of anharmonic diatomic oscillators in supersonic expansions are used to show the extent to which the small anharmonicity of gases like CO can cause significant overpopulations of upper vibrational states. When mixtures of CO and N2 are considered, radiative gain on many of the vibration-rotation transitions of CO is predicted. Experiments are described that qualitatively verify the predictions by demonstrating laser oscillation in CO-N2 expansions. The resulting CO-N2 gasdynamic laser displays performance characteristics that equal or exceed those of similar CO2 lasers.

  8. Gas dynamic lasers

    Hill, R.J.; Jewell, N.T.

    1975-01-01

    In a high powered laser system it is proposed that combustion gases be bled off from a gas turbine engine and their composition adjusted by burning extra fuel in the bleed gases or adding extra substances. Suitable aerodynamic expansion produces a population inversion resulting in laser action in the CO 2 species. Alternatively, bleed gases may be taken from the high pressure compressor of the gas turbine engine and an appropriate fuel burned therein. If required, other adjustments may also be made to the composition and the resulting gaseous mixture subjected to aerodynamic expansion to induce laser action as before. (auth)

  9. Monoenergetic laser wakefield acceleration

    N. E. Andreev

    2000-02-01

    Full Text Available Three dimensional test particle simulations are applied to optimization of the plasma-channeled laser wakefield accelerator (LWFA operating in a weakly nonlinear regime. Electron beam energy spread, emittance, and luminosity depend upon the proportion of the electron bunch size to the plasma wavelength. This proportion tends to improve with the laser wavelength increase. We simulate a prospective two-stage ∼1GeV LWFA with controlled energy spread and emittance. The input parameters correspond to realistic capabilities of the BNL Accelerator Test Facility that features a picosecond-terawatt CO_{2} laser and a high-brightness electron gun.

  10. Simulations of laser undulators

    Milton, S. V.; Biedron, S. B.; Einstein, J. E.

    2016-09-01

    We perform a series of single-pass, one-D free-electron laser simulations based on an electron beam from a standard linear accelerator coupled with a so-called laser undulator, a specialized device that is more compact than a standard undulator based on magnetic materials. The longitudinal field profiles of such lasers undulators are intriguing as one must and can tailor the profile for the needs of creating the virtual undulator. We present and discuss several results of recent simulations and our future steps.

  11. Diatomic gasdynamic lasers

    McKenzie, R.L.

    1971-12-01

    Predictions from a numerical model of the vibrational relaxation of anharmonic diatomic oscillators in supersonic expansions are used to show the extent to which the small anharmonicity of gases like CO can cause significant over-populations of upper vibrational states. When mixtures of CO and N 2 are considered, radiative gain on many of the vibration-rotation transitions of CO is predicted. Experiments are described that qualitatively verify the predictions by demonstrating laser oscillation in CO-N 2 expansions. The resulting CO-N 2 gasdynamic laser displays performance characteristics that equal or exceed those of similar CO 2 lasers

  12. High power excimer laser

    Oesterlin, P.; Muckenheim, W.; Basting, D.

    1988-01-01

    Excimer lasers emitting more than 200 W output power are not commercially available. A significant increase requires new technological efforts with respect to both the gas circulation and the discharge system. The authors report how a research project has yielded a laser which emits 0.5 kW at 308 nm when being UV preionized and operated at a repetition rate of 300 Hz. The laser, which is capable of operating at 500 Hz, can be equipped with an x-ray preionization module. After completing this project 1 kW output power will be available

  13. Plasmonic colour laser printing

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil

    2016-01-01

    -beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation...... that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours...

  14. Optimising Laser Tattoo Removal

    Sardana, Kabir; Ranjan, Rashmi; Ghunawat, Sneha

    2015-01-01

    Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal. PMID:25949018

  15. Laser welding engineering

    Bhieh, N. M.; El Eesawi, M. E.; Hashkel, A. E.

    2007-01-01

    Laser welding was in its early life used mainly for unusual applications where no other welding process would be suitable that was twenty five years ago. Today, laser welding is a fully developed part of the metal working industry, routinely producing welds for common items such as cigarette lighters, which springs, motor/transformer lamination, hermetic seals, battery and pacemaker cans and hybrid circuit packages. Yet very few manufacturing engineering have seriously considers employing lasers in their own operations. Why? There are many reasons, but a main one must be not acquainted with the operation and capabilities of a laser system. Other reasons, such as a relatively high initial cost and a concern about using lasers in the manufacturing environment, also are frequently cited, and the complexity of the component and flexibility of the light delivery system. Laser welding could be used in place of many different standard processes, such as resistance (spot or seam), submerged arc, RF induction, high-frequency resistance, ultrasonic and electronic and electron-beam. while each of these techniques has established an independent function in the manufacturing world, the flexible laser welding approach will operate efficiently and economically in many different applications. Its flexibility will even permit the welding system to be used for other machining function, such as drilling, scribing, sealing and serializing. In this article, we will look at how laser welding works and what benefits it can offer to manufacturing engineers. Some industry observers state that there are already 2,000 laser machine tools being used for cutting, welding and drilling and that the number could reach 30,000 over the next 15 years as manufacturing engineers become more aware of the capabilities of lasers [1). While most laser applications are dedicated to one product or process that involves high-volume, long-run manufacturing, the flexibility of a laser to supply energy to hard

  16. Laser Megajoule synchronization system

    Luttmann, M.; Pastor, J.F; Drouet, V.; Prat, M.; Raimbourg, J.; Adolf, A.

    2011-01-01

    This paper describes the synchronisation system under development on the Laser Megajoule (LMJ) in order to synchronize the laser quads on the target to better than 40 ps rms. Our architecture is based on a Timing System (TS) which delivers trigger signals with jitter down to 15 ps rms coupled with an ultra precision timing system with 5 ps rms jitter. In addition to TS, a sensor placed at the target chamber center measures the arrival times of the 3 omega nano joule laser pulses generated by front end shots. (authors)

  17. Laser applications in neurosurgery

    Cerullo, Leonard J.

    1985-09-01

    The "false start" of the laser in neurosurgery should not be misconstrued as a denial of the inherent advantages of precision and gentleness in dealing with neural tissue. Rather, early investigators were frustrated by unrealistic expectations, cumbersome equipment, and a general ignorance of microtechnique. By the early 70s, microneurosurgery was well established, surgical laser equipment for free hand and microlinked application had been developed, and a more realistic view of the limitations of the laser had been established. Consequently, the late 70s really heralded the renaissance of the laser in neurosurgery. Since then, there has been an overwhelming acceptance of the tool in a variety of clinical situations, broadly categorized in five groups. 1)|Perhaps the most generally accepted area is in the removal of extra-axial tumors of the brain and spinal cord. These tumors, benign by histology but treacherous by location, do not present until a significant amount of neurological compensation has already occurred. The application of additional trauma to the neural tissue, whether by further tumor growth or surgical manipulation, frequently results in irreversible damage. Here, the ability of the laser to vaporize tissue, in a fairly hemostatic fashion, without mechanical or thermal damage to sensitive surrounding tissues, is essential. 2)|The ability to incise delicate neural tissue with minimal spread of thermal destruction to adjacent functioning tissue makes the laser the ideal instrument when tumors deep under the surface are encountered in the brain or spinal cord. Thus, the second group of applications is in the transgression of normal neural structures to arrive at deeper pathological tissue. 3)|The third area of benefit for the laser in neurosurgery has been in the performance of neuroablative procedures, calling for deliberate destruction of functioning neural tissue in a controlled fashion. Again, the precision and shape confinement of the destructive

  18. Laser tests of silicon detectors

    Dolezal, Zdenek; Escobar, Carlos; Gadomski, Szymon; Garcia, Carmen; Gonzalez, Sergio; Kodys, Peter; Kubik, Petr; Lacasta, Carlos; Marti, Salvador; Mitsou, Vasiliki A.; Moorhead, Gareth F.; Phillips, Peter W.; Reznicek, Pavel; Slavik, Radan

    2007-01-01

    This paper collects experiences from the development of a silicon sensor laser testing setup and from tests of silicon strip modules (ATLAS End-cap SCT), pixel modules (DEPFET) and large-area diodes using semiconductor lasers. Lasers of 1060 and 680 nm wavelengths were used. A sophisticated method of focusing the laser was developed. Timing and interstrip properties of modules were measured. Analysis of optical effects involved and detailed discussion about the usability of laser testing for particle detectors are presented

  19. Multispot fiber laser welding

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been examined and evaluated. It is found that both diamond turned DOE’s in zinc sulphide and multilevel etched DOE’s (Diffractive Optical Elements) in fused silica have a good performance. Welding with multiple beams in a butt joint configuration has been tested. Results are presented, showing it has...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...

  20. Lasers and holography

    Kock, Winston E

    1981-01-01

    Accessible, illustrated introduction covers wave patterns and coherence, summarizes the development of lasers and the phenomenon of wave diffraction, and describes zone plates and properties of holograms. 1981 edition.

  1. Jupiter Laser Facility

    Federal Laboratory Consortium — The Jupiter Laser Facility is an institutional user facility in the Physical and Life Sciences Directorate at LLNL. The facility is designed to provide a high degree...

  2. Blackbody metamaterial lasers

    Liu, Changxu

    2015-01-01

    We investigate both theoretically and experimentally a new type of laser, which exploits a broadband light "condensation" process sustained by the stimulated amplification of an optical blackbody metamaterial. © 2014 Optical Society of America.

  3. Electra Laser Facility

    Federal Laboratory Consortium — FUNCTION: The Electra Laser Facility is used to develop the science and technology needed to develop a reliable, efficient, high-energy, repetitively pulsed krypton...

  4. Airclad fiber laser technology

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes

    2011-01-01

    High-power fiber lasers and amplifiers have gained tremendous momentum in the last 5 years. Many of the traditional manufacturers of gas and solid-state lasers are now pursuing the fiber-based systems, which are displacing the conventional technology in many areas. High-power fiber laser systems...... require reliable fibers with large cores, stable mode quality, and good power handling capabilities-requirements that are all met by the airclad fiber technology. In the present paper we go through many of the building blocks needed to build high-power systems and we show an example of a complete airclad...... laser system. We present the latest advancements within airclad fiber technology including a new 100 m single-mode polarization-maintaining rod-type fiber capable of amplifying to megawatt power levels. Furthermore, we describe the novel airclad-based pump combiners and their use in a completely...

  5. Laser fusion overview

    Nuckolls, J.

    1976-01-01

    Because of recent breakthroughs in the target area, and in the glass laser area, the scientific feasibility of laser fusion--and of inertial fusion--may be demonstrated in the early 1980's. Then the development in that time period of a suitable laser (or storage ring or other driving source) would make possible an operational inertial fusion reactor in this century. These are roughly the same time scales as projected by the Tokamak magnetic confinement approach. It thus appears that the 15-20 year earlier start by magnetic confinement fusion may be overcome. Because inertial confinement has been demonstrated, and inertial fusion reactors may operate on smaller scales than Tokamaks, laser fusion may have important technical and economic advantages

  6. Laser therapy for periodontitis

    Efanov, O. I.

    2001-04-01

    An investigation was made of applying pulsed (lambda) equals 0.89 micrometers laser radiation in the treatment for early diagnosed periodontitis. The investigation was made on 65 patients (47 patients constituted the experimental group and 18 patients constituted a control group) affected by periodontitis. Clinical and functional tests revealed that laser therapy produced a string effect on the course of the illness. It reduced bleeding, inflammation, and pruritus. However, it did not produce an affect on electroexcitation. Biomicroscopic examinations and periodontium rheography revealed that the gingival blood flow became normal after the course of laser therapy. The capillary permeability and venous congestion decreased, which was confirmed by the increased time of vacuum tests, raised gingival temperature, reduced tissue clearance, and increased oxygen tension. Apart from that, laser therapy subsided fibrinolysis, proteolytic tissue activity, and decreased the exudative inflammation of periodontium.

  7. Laser Guidance Analysis Facility

    Federal Laboratory Consortium — This facility, which provides for real time, closed loop evaluation of semi-active laser guidance hardware, has and continues to be instrumental in the development...

  8. Airclad fiber laser technology

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes

    2008-01-01

    High-power fiber lasers and amplifiers have gained tremendous momentum in the last five years, and many of the traditional manufactures of gas and solid-state lasers are pursuing the attractive fiber-based systems, which are now displacing the old technology in many areas. High-power fiber laser...... systems require specially designed fibers with large cores and good power handling capabilities - requirements that are all met by the airclad fiber technology. In the present paper we go through many of the building blocks needed to build high-power systems and we show an example of a complete airclad...... laser system. We present the latest advancements within airclad fiber technology including a new 70 μm single-mode polarization-maintaining rod-type fiber capable of amplifying to MW power levels. Furthermore we describe the novel airclad based pump combiners and their use in a completely monolithic 350...

  9. Improved Laser Vibration Radar

    Hilaire, Pierre

    1998-01-01

    .... This thesis reconfigured an existing CO2 laboratory laser radar system that is capable of measuring the frequencies of vibration of a simulated target into a more compact and rugged form for field testing...

  10. Physics of laser plasma

    Rubenchik, A.; Witkowski, S.

    1991-01-01

    This book provides a comprehensive review of laser fusion plasma physics and contains the most up-to-date information on high density plasma physics and radiation transport, useful for astrophysicists and high density physicists

  11. Fusion reactor pumped laser

    Jassby, D.L.

    1988-01-01

    A nuclear pumped laser is described comprising: a toroidal fusion reactor, the reactor generating energetic neutrons; an annular gas cell disposed around the outer periphery of the reactor, the cell including an annular reflecting mirror disposed at the bottom of the cell and an annular output window disposed at the top of the cell; a gas lasing medium disposed within the annular cell for generating output laser radiation; neutron reflector material means disposed around the annular cell for reflecting neutrons incident thereon back into the gas cell; neutron moderator material means disposed between the reactor and the gas cell and between the gas cell and the neutron reflector material for moderating the energy of energetic neutrons from the reactor; converting means for converting energy from the moderated neutrons to energy pumping means for pumping the gas lasing medium; and beam compactor means for receiving output laser radiation from the annular output window and generating a single output laser beam therefrom

  12. Compact semiconductor lasers

    Yu, Siyuan; Lourtioz, Jean-Michel

    2014-01-01

    This book brings together in a single volume a unique contribution by the top experts around the world in the field of compact semiconductor lasers to provide a comprehensive description and analysis of the current status as well as future directions in the field of micro- and nano-scale semiconductor lasers. It is organized according to the various forms of micro- or nano-laser cavity configurations with each chapter discussing key technical issues, including semiconductor carrier recombination processes and optical gain dynamics, photonic confinement behavior and output coupling mechanisms, carrier transport considerations relevant to the injection process, and emission mode control. Required reading for those working in and researching the area of semiconductors lasers and micro-electronics.

  13. YAG Laser or bur

    2018-02-23

    Feb 23, 2018 ... for the clinical durability of resin-based dental restorations.[1]. Microleakage ... studies evaluating the use of laser systems in primary teeth for cavity ... sealed with glass ionomer restorative material (Fuji. II LC, GC Corporation ...

  14. Foundations of laser spectroscopy

    Stenholm, Stig

    2005-01-01

    A simple presentation of the theoretical foundations of steady-state laser spectroscopy, this text helps students to apply theory to calculations with a systematic series of examples and exercises. 1984 edition.

  15. Thermonuclear fusion by laser

    Delpech, J.-F.; Fabre, Edouard.

    1978-01-01

    This paper is intended to describe the principle of inetia containment by laser and the research effort undertaken for this purpose. After having enumerated the principal thermonuclear reactions useful for fusion, the authors derive the rhoR criterion that characterizes inertia containment, as well as the Lawson criterion in the case of magnetic containment. The main physics problems involved in inertia containment by laser are enunciated and the article ends with a review of means resorted to in France and abroad for studying this problem. This review also reports C.N.R.S. bustling in this field, within the scope of competence of G.I.L.M. (Groupement de Recherches Coordonnees sur l'Interaction Laser-Matiere = Group for coordinated investigation of matter-laser interaction) established in Paris at the Ecole Polytechnique [fr

  16. DIFFRACTION SYNCHRONIZATION OF LASERS,

    semiconductor lasers while suppressing parasitic generation in the plane of the mirror. The diffraction coupling coefficient of open resonators is calculated, and the stability conditions of the synchronized system is determined.

  17. Efficiencies of laser dyes for atomic vapor laser isotope separation

    Maeda, Mitsuo; Oki, Yuji; Uchiumi, Michihiro; Takao, Takayuki; Igarashi, Kaoru; Shimamoto, Kojiro.

    1995-01-01

    Efficiencies of 30 laser dyes for the atomic vapor laser isotope separation (AVLIS) are experimentally evaluated with a dye laser pumped by a frequency-doubled Nd:YAG laser. On the other hand, a simulation code is developed to describe the laser action of Rhodamine 6G, and the dependence of the laser efficiency on the pump wavelength is calculated. Following conclusions are obtained by these considerations:space: 1) Pyrromethene 567 showed 16% higher laser efficiency than Rhodamine 6G by 532 nm pumping, and Pyrromethene 556 has an ability to provide better efficiency by green light pumping with a Cu vapor laser; 2) Kiton red 620 and Rhodamine 640, whose efficiencies were almost the same as Rhodamine 6G by 532 nm pumping, will show better efficiencies by two-wavelength pumping with a Cu vapor laser. (author)

  18. Future prospects of laser diodes and fiber lasers

    Ueda, Ken-ichi

    2000-01-01

    For the next century we should develop new concepts for coherent control of light generation and propagation. Owing to the recent development of ultra fine structures in semiconductor lasers, fiber lasers, and various kinds of waveguide structure, we can make optical devices which control the light propagation artificially. But, the phase locking and phase control of multiple laser oscillators are one of the most important directions of laser science and technology. The coherent summation has been a dream of laser since 1960. Is it possible to solve this old and quite challenging problem for laser science? This is also a very basic concept because the laser action based on the stimulated emission is the process of coherent summation of huge number of photons emitted from individual atoms. In this paper, I discuss the fundamental direction of laser research in the next ten or twenty years. The active optics and laser technology should be combined intrinsically in near future. (author)

  19. High-energy molecular lasers self-controlled volume-discharge lasers and applications

    Apollonov, V V

    2016-01-01

    This book displays the physics and design of high-power molecular lasers. The lasers described are self-controlled volume-discharge lasers. The book explains self-sustained discharge lasers, self-initiated discharge lasers and technical approaches to laser design. Important topics discussed are laser efficiency, laser beam quality and electric field homogeneity. The book contains many new innovative applications.

  20. Transurethral vaporesection of prostate: diode laser or thulium laser?

    Tan, Xinji; Zhang, Xiaobo; Li, Dongjie; Chen, Xiong; Dai, Yuanqing; Gu, Jie; Chen, Mingquan; Hu, Sheng; Bai, Yao; Ning, Yu

    2018-05-01

    This study compared the safety and effectiveness of the diode laser and thulium laser during prostate transurethral vaporesection for treating benign prostate hyperplasia (BPH). We retrospectively analyzed 205 patients with BPH who underwent a diode laser or thulium laser technique for prostate transurethral vaporesection from June 2016 to June 2017 and who were followed up for 3 months. Baseline characteristics of the patients, perioperative data, postoperative outcomes, and complications were compared. We also assessed the International Prostate Symptom Score (IPSS), quality of life (QoL), maximum flow rate (Q max ), average flow rate (AFR), and postvoid residual volume (PVR) at 1 and 3 months postoperatively to evaluate the functional improvement of each group. There were no significant differences between the diode laser and thulium laser groups related to age, prostate volume, operative time, postoperative hospital stays, hospitalization costs, or perioperative data. The catheterization time was 3.5 ± 0.8 days for the diode laser group and 4.7 ± 1.8 days for the thulium laser group (p diode laser and thulium laser contributes to safe, effective transurethral vaporesection in patients with symptomatic BPH. Diode laser, however, is better than thulium laser for prostate transurethral vaporesection because of its shorter catheterization time. The choice of surgical approach is more important than the choice of laser types during clinical decision making for transurethral laser prostatectomy.

  1. Pulsed chemical laser

    Jacobson, T.V.; Kimbell, G.H.

    1975-01-01

    A hydrogen fluoride laser capable of operating super radiantly and at atmospheric pressure is described. A transverse electrical discharge is utilized to energize the reaction of a hydrogen donor to provide hydrogen fluoride in a metastable energy state which reverts to a stable state by laser action. A large range of hydrogen and fluorine donors is disclosed. A preferred pair of donors is sulphur hexafluoride and propane. Helium is frequently added to the gas mix to act as a buffer. (U.S.)

  2. Hybrid vertical cavity laser

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  3. Laser Resurfacing Pearls

    Shah, Sonia; Alam, Murad

    2012-01-01

    Ablative skin resurfacing using the carbon dioxide laser was long considered the gold standard for treatment of photoaging, acne scars, and rhytids. However, conventional full-face carbon dioxide resurfacing is associated with significant risk of side effects and a prolonged postoperative recovery period. Fractional resurfacing has recently revolutionized laser surgery by offering close to comparable results with minimal side effects and a more rapid recovery. Although fractional devices have...

  4. Laser cooling of solids

    Epstein, Richard I [Los Alamos National Laboratory; Sheik-bahae, Mansoor [UNM

    2008-01-01

    We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and semiconductors.

  5. Laser radiation protection

    Pantelic, D.; Muric, B.; Vasiljevic, D.

    2011-01-01

    We have presented the effects of laser radiation on human organism, with special emphasize on eye as the most sensitive organ. It was pointed-out that there are many parameters that should be taken into account when determining the level of protection from laser light. In that respect it is important to be aware of international standards that regulate this area. In addition, we have described a new material which efficiently protects human eye, by formation of microlens and carbonization. [sr

  6. SHIVA laser: nearing completion

    Glaze, J.A.; Godwin, R.O.

    1977-01-01

    Construction of the Shiva laser system is nearing completion. This laser will be operating in fall 1977 and will produce over 20 terawatts of focusable power in a subnanosecond pulse. Fusion experiments will begin early in 1978. It is anticipated that thermonuclear energy release equal to one percent that of the incident light energy will be achieved with sub-millimeter deuterium-tritium targets. From other experiments densities in excess of a thousand times that of liquid are also expected

  7. Laser Scanning in Forests

    Håkan Olsson

    2012-09-01

    Full Text Available The introduction of Airborne Laser Scanning (ALS to forests has been revolutionary during the last decade. This development was facilitated by combining earlier ranging lidar discoveries [1–5], with experience obtained from full-waveform ranging radar [6,7] to new airborne laser scanning systems which had components such as a GNSS receiver (Global Navigation Satellite System, IMU (Inertial Measurement Unit and a scanning mechanism. Since the first commercial ALS in 1994, new ALS-based forest inventory approaches have been reported feasible for operational activities [8–12]. ALS is currently operationally applied for stand level forest inventories, for example, in Nordic countries. In Finland alone, the adoption of ALS for forest data collection has led to an annual savings of around 20 M€/year, and the work is mainly done by companies instead of governmental organizations. In spite of the long implementation times and there being a limited tradition of making changes in the forest sector, laser scanning was commercially and operationally applied after about only one decade of research. When analyzing high-ranked journal papers from ISI Web of Science, the topic of laser scanning of forests has been the driving force for the whole laser scanning research society over the last decade. Thus, the topic “laser scanning in forests” has provided a significant industrial, societal and scientific impact. [...

  8. CO2 laser cutting

    Powell, John

    1998-01-01

    The laser has given manufacturing industry a new tool. When the laser beam is focused it can generate one of the world's most intense energy sources, more intense than flames and arcs, though similar to an electron beam. In fact the intensity is such that it can vaporise most known materials. The laser material processing industry has been growing swiftly as the quality, speed and new manufacturing possibilities become better understood. In the fore of these new technologies is the process of laser cutting. Laser cutting leads because it is a direct process substitu­ tion and the laser can usually do the job with greater flexibility, speed and quality than its competitors. However, to achieve these high speeds with high quality con­ siderable know how and experience is required. This information is usually carefully guarded by the businesses concerned and has to be gained by hard experience and technical understanding. Yet in this book John Powell explains in lucid and almost non­ technical language many o...

  9. Untitled

    Retinal photocoagulation is commonly used in the treatment of retinopathy. ... Photodisruption is defined as the use of high-power ionizing laser pulses to disrupt ... sonic waves is stimulated Brillouin scattering in which the laser light generates.

  10. Reverse spontaneous laser line sweeping in ytterbium fiber laser

    Navrátil, Petr; Peterka, Pavel; Honzátko, Pavel; Kubeček, V.

    2017-01-01

    Roč. 14, č. 3 (2017), č. článku 035102. ISSN 1612-2011 R&D Projects: GA ČR(CZ) GA16-13306S Institutional support: RVO:67985882 ; RVO:68378271 Keywords : laser line sweeping * ytterbium * fiber lasers Subject RIV: BH - Optics, Masers, Lasers; BH - Optics, Masers, Lasers (FZU-D) OBOR OECD: Optics (including laser optics and quantum optics); Optics (including laser optics and quantum optics) (FZU-D) Impact factor: 2.537, year: 2016

  11. Laser Diode Pumped Solid State Lasers

    1987-01-01

    Report N66001-83-C-0071, 17 April 1986, prepared for NOSC. 4.6 W.T. Welford, R. Winston , "The Option of Nonimaging Concentrators ," Academic Press, 1978...by non-imac optics such as reflective or refractive flux concentrators . Simple considerations regarding the optimum pumping configuration, high marks...reduced if the arrays can stand-off from the Nd:YAG laser. As mentioned before, compound parabolic concentrators or refractive optics cat employed to

  12. Greco Laser-matter interaction

    1986-01-01

    Research program in 1985 at GRECO ILM (Group of Coordinated Research: Interaction Laser Matter) continued with its principal direction in fundamental physics of laser inertial confinement; also researches on X-ray lasers hare been undergone and new high power laser application fields with particle acceleration, material processing and X-ray sources. A six beam laser was operated. Wavelength effects were studied. Atomic physics was deeply stressed as dense medium diagnostics from multicharged ions. Research development in ultra-dense medium was also important X-ray laser research gave outstanding results. New research fields were developed this year: laser acceleration of particles by wave beating or Raman instability; dense laser produced plasma use as X-ray source; material processing by laser shocks [fr

  13. Ultracompact Pseudowedge Plasmonic Lasers and Laser Arrays.

    Chou, Yu-Hsun; Hong, Kuo-Bin; Chang, Chun-Tse; Chang, Tsu-Chi; Huang, Zhen-Ting; Cheng, Pi-Ju; Yang, Jhen-Hong; Lin, Meng-Hsien; Lin, Tzy-Rong; Chen, Kuo-Ping; Gwo, Shangjr; Lu, Tien-Chang

    2018-02-14

    Concentrating light at the deep subwavelength scale by utilizing plasmonic effects has been reported in various optoelectronic devices with intriguing phenomena and functionality. Plasmonic waveguides with a planar structure exhibit a two-dimensional degree of freedom for the surface plasmon; the degree of freedom can be further reduced by utilizing metallic nanostructures or nanoparticles for surface plasmon resonance. Reduction leads to different lightwave confinement capabilities, which can be utilized to construct plasmonic nanolaser cavities. However, most theoretical and experimental research efforts have focused on planar surface plasmon polariton (SPP) nanolasers. In this study, we combined nanometallic structures intersecting with ZnO nanowires and realized the first laser emission based on pseudowedge SPP waveguides. Relative to current plasmonic nanolasers, the pseudowedge plasmonic lasers reported in our study exhibit extremely small mode volumes, high group indices, high spontaneous emission factors, and high Purell factors beneficial for the strong interaction between light and matter. Furthermore, we demonstrated that compact plasmonic laser arrays can be constructed, which could benefit integrated plasmonic circuits.

  14. Lasers in endodontics: an overview

    Frentzen, Matthias; Braun, Andreas; Koort, Hans J.

    2002-06-01

    The interest in endodontic use of dental laser systems is increasing. Developing laser technology and a better understanding of laser effects widened the spectrum of possible endodontic indications. Various laser systems including excimer-, argon+-, diode-, Nd:YAG-, Er:YAG- and CO2-lasers are used in pulp diagnosis, treatment of hypersensitivity, pulp capping, sterilization of root canals, root canal shaping and obturation or apicoectomy. With the development of new delivery systems - thin and flexible fibers - for many different wavelengths laser applications in endodontics may increase. Since laser devices are still relatively costly, access to them is limited. Most of the clinical applications are laser assisted procedures such as the removing of pulp remnants and debris or disinfection of infected root canals. The essential question is whether a laser can provide improved treatment over conventional care. To perform laser therapy in endodontics today different laser types with adopted wavelengths and pulse widths are needed, each specific to a particular application. Looking into the future we will need endodontic laser equipment providing optimal laser parameters for different treatment modalities. Nevertheless, the quantity of research reports from the last decade promises a genuine future for lasers in endodontics.

  15. Development of frequency tunable Ti:sapphire laser and dye laser pumped by a pulsed Nd:YAG laser

    Yi, Jong Hoon; Horn, Roland; Wendt, K.

    2001-01-01

    We investigated lasing characteristics of two kinds of tunable laser, liquid dye laser and solid Ti:sapphire crystal laser, pumped by high pulse repetition rate Nd:YAG laser. Dye laser showed drastically reduced pulsewidth compared with that of pump laser and it also contained large amount of amplified spontaneous emission. Ti:sapphire laser showed also reduced pulsewidth. But, the laser conversion pump laser and Ti:sapphire laser pulse, we used a Brewster-cut Pockel's cell for Q-switching. The laser was frequency doubled by a type I BBO crystal outside of the cavity.

  16. Femtosecond Fiber Lasers

    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

  17. Lasers '90: Proceedings of the 13th International Conference on Lasers and Applications, San Diego, CA, Dec. 10-14, 1990

    Harris, D.G.; Herbelin, J.

    1991-01-01

    The general topics considered are: x-ray lasers; FELs; solid state lasers; techniques and phenomena of ultrafast lasers; optical filters and free space laser communications; discharge lasers; tunable lasers; applications of lasers in medicine and surgery; lasers in materials processing; high power lasers; dynamics gratings, wave mixing, and holography; up-conversion lasers; lidar and laser radar; laser resonators; excimer lasers; laser propagation; nonlinear and quantum optics; blue-green technology; imaging; laser spectroscopy; chemical lasers; dye lasers; and lasers in chemistry

  18. High power ultrashort pulse lasers

    Perry, M.D.

    1994-01-01

    Small scale terawatt and soon even petawatt (1000 terawatt) class laser systems are made possible by application of the chirped-pulse amplification technique to solid-state lasers combined with the availability of broad bandwidth materials. These lasers make possible a new class of high gradient accelerators based on the large electric fields associated with intense laser-plasma interactions or from the intense laser field directly. Here, we concentrate on the laser technology to produce these intense pulses. Application of the smallest of these systems to the production of high brightness electron sources is also introduced

  19. Injection-controlled laser resonator

    Chang, J.J.

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality. 5 figs.

  20. Laser safety in the lab

    Barat, Ken L

    2012-01-01

    There is no more challenging setting for laser use than a research environment. In almost every other setting the laser controls count on engineering controls, and human exposure is kept to a minimum. In research, however, the user often manipulates the optical layout and thereby places him or herself in peril, but this does not mean that accidents and injury are unavoidable. On the contrary, laser accidents can be avoided by following a number of simple approaches. [i]Laser Safety in the Lab[/i] provides the laser user and laser safety officer with practical guidelines from housekeeping to ey