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Sample records for monocular corneal opacity

  1. Pentacam-based phototherapeutic keratectomy outcome in superficial corneal opacities

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    Rashad MA

    2012-06-01

    Full Text Available Mohammad A RashadOphthalmology Department, Faculty of Medicine, Ain Shams University, Cairo, EgyptPurpose: This study aimed to evaluate the effectiveness of phototherapeutic keratectomy (PTK as an alternative treatment to keratoplasty using the Pentacam to assess depth of dense opacities.Methodology: PTK was performed in eleven eyes of ten patients with superficial corneal opacities after assessment by Scheimpflug images of the Pentacam for central corneal thickness (CCT and opacity level and depth.Results: The best-corrected spectacle visual acuity (BCSVA significantly improved. The preoperative mean logMAR was 0.85 (0.14 decimal equivalent, 6/42 Snellen's equivalent, and the final postoperative mean logMAR was 0.58 (0.26 decimal equivalent, 6/23 Snellen's equivalent. The mean preoperative CCT was 465.64 ± 71.94 µm. The mean programmed ablation depth was 142.09 ± 47.58 µm. The programmed ablation depth was correlated to mean logMAR early (1 month and not correlated later (6 months. None of the eyes lost lines of BCSVA or developed serious complications, such as keratectasia, delayed epithelialization, or corneal melting.Conclusion: Corneal scars extending beyond the anterior one-fifth of the cornea can be treated safely and effectively by PTK due to the smoothing effect, with reduction of the cylinder rather than complete opacity removal. This can decrease the need for keratoplasty.Keywords: phototherapeutic keratectomy, PTK, corneal opacities, Pentacam

  2. Image Analysis on Corneal Opacity:A Novel Method to Estimate Postmortem Interval in Rabbits

    Institute of Scientific and Technical Information of China (English)

    周兰; 刘艳; 刘良; 卓荦; 梁曼; 杨帆; 任亮; 朱少华

    2010-01-01

    Corneal opacity is one of the most commonly used parameters for estimating postmortem interval(PMI).This paper proposes a new method to study the relationship between changes of corneal opacity and PMI by processing and analyzing cornea images.Corneal regions were extracted from images of rabbits' eyes and described by color-based and texture-based features,which could represent the changes of cornea at different PMI.A KNN classifier was used to reveal the association of image features and PMI.The result of...

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

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    E. Yu. Markova

    2014-01-01

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

  4. A novel congenital ichthyosiform syndrome with associated panhypopituitarism, corneal opacities and mental retardation.

    Science.gov (United States)

    Pandhi, Deepika; Khanna, Deepshikha; Singal, Archana; Madhu, Sri Venkata

    2007-11-01

    A 15-year-old male presented with ichthyosis since infancy with panhypopituitarism, short stature and knock-knees, delayed puberty, high scrotal retractile testes, mental retardation and corneal opacities. He developed recurrent tinea capitis and tinea corporis. The clinical symptomatology indicates that this case cannot be considered as a subtype of inherited ichthyosis group, but suggests a new syndrome as a separate nosologic entity. Two previously reported cases with possibly the same syndrome also had ichthyosis associated with variable endocrinopathy. Thorough endocrinological evaluation and appropriate intervention in patients of ichthyosis with short stature may reduce the morbidity associated with retarded skeletal growth and gonadal maturation.

  5. Opacity

    CERN Document Server

    Huebner, Walter F

    2014-01-01

    The interaction of radiation with matter is a fundamental process in the universe; in particular, the absorption and scattering of radiation by matter (the opacity) govern the formation, evolution, and structure of stars and planets.  But opacity is also important in many terrestrial applications in which radiation is the dominant means of energy transfer, such as controlled nuclear-fusion, laser ablation, atmospheric entry and reentry, and the "greenhouse" effect.  This book covers all aspects of opacity and equations of state for plasmas, gases, vapors, and dust and emphasizes the continuous transformation of phases and molecular compositions with changing density and temperature under conditions of local thermodynamic equilibrium (LTE) while preserving the basic abundances of the chemical elements in a mixture.

  6. Effects of Silicone Hydrogel Contact Lens Application on Corneal High-order Aberration and Visual Guality in Patients with Corneal Opacities

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    Sevda Aydın Kurna

    2012-03-01

    Full Text Available Pur po se: Evaluation of the corneal high-order aberrations and visual quality changes after application of silicone hydrogel contact lenses in patients with corneal opacities due to various etiologies. Ma te ri al and Met hod: Fifteen eyes of 13 patients with corneal opacities were included in the study. During the ophthalmologic examination before and after contact lens application, visual acuity was measured with Snellen acuity chart and contrast sensitivity - with Bailey-Lowie Charts in letters. Aberrations were measured with corneal aberrometer (NIDEK Magellan Mapper under a naturally dilated pupil. Spherical aberration, coma, trefoil, irregular astigmatism and total high-order root mean square (RMS values were recorded. Measurements were repeated with balafilcon A lenses (PureVision 2 HD, B&L on all patients. Re sults: Patient age varied between 23 and 50 years. Two eyes had subepithelial infiltrates due to adenoviral keratitis, 1 had nebulae due to previous infections or trauma, and 2 had Salzmann’s nodular degeneration. We observed a mean increase of 1 line in visual acuity and 5 letters in contrast sensitivity with contact lenses versus glasses in the patients. Mean RMS values of spherical aberration, irregular astigmatism and total high-order aberrations decreased significantly with contact lenses. Dis cus si on: Silicone hydrogel soft contact lenses may improve visual quality by decreasing the corneal aberrations in patients with corneal opacities. (Turk J Ophthalmol 2012; 42: 97-102

  7. Improvement of the Bovine Corneal Opacity and Permeability (BCOP) assay as an in vitro alternative to the Draize rabbit eye irritation test.

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    Verstraelen, Sandra; Jacobs, An; De Wever, Bart; Vanparys, Philippe

    2013-06-01

    Measurement of ocular irritancy is a necessary step in the safety evaluation of both industrial and consumer products. Assessment of the acute eye irritation potential is therefore part of the international regulatory requirements for testing of chemicals. The Bovine Corneal Opacity and Permeability (BCOP) assay is generally accepted as a valid in vitro alternative method to the Draize eye irritation test to detect corrosive and severe eye irritants (category 1), but has not proven sensitive enough to discriminate accurately moderate (category 2A/2B) to mild and non-irritating compounds. In the currently accepted BCOP assay, opacity is determined by the amount of light transmission through the cornea, and permeability is determined by the amount of sodium fluorescein dye that passes through all corneal cell layers. Both measurements are used to assign an In Vitro Irritancy Score (IVIS) for prediction of the in vivo ocular irritation potential of a test substance. Nowadays, opacity is measured by an OP-KIT opacitometer providing a center-weighted reading of light transmission by measuring changes in voltage when the transmission of white light passes through the cornea alters. As a consequence, this may underestimate opacity that develops as spots or heterogeneous opaque areas on the periphery of an isolated cornea. A prototype of a laser light-based opacitometer (PLLBO) allowing better measurement of opacities was developed by Van Goethem et al. (2010). This new device showed improved sensitivity to detect subtle changes in corneal transparency. Furthermore, the new opacitometer allowed the analysis of the complete corneal surface and was able to detect more efficiently opaque spots located along the sides of the excised corneas. A further improved prototype of the PLLBO was constructed in combination with a camera and a speckle noise reducer. Treatment conditions of the corneas in the cornea holders were optimized in order to mimic more the real in vivo situation

  8. Multilevel Analysis of Trachomatous Trichiasis and Corneal Opacity in Nigeria: The Role of Environmental and Climatic Risk Factors on the Distribution of Disease.

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    Jennifer L Smith

    Full Text Available The distribution of trachoma in Nigeria is spatially heterogeneous, with large-scale trends observed across the country and more local variation within areas. Relative contributions of individual and cluster-level risk factors to the geographic distribution of disease remain largely unknown. The primary aim of this analysis is to assess the relationship between climatic factors and trachomatous trichiasis (TT and/or corneal opacity (CO due to trachoma in Nigeria, while accounting for the effects of individual risk factors and spatial correlation. In addition, we explore the relative importance of variation in the risk of trichiasis and/or corneal opacity (TT/CO at different levels. Data from the 2007 National Blindness and Visual Impairment Survey were used for this analysis, which included a nationally representative sample of adults aged 40 years and above. Complete data were available from 304 clusters selected using a multi-stage stratified cluster-random sampling strategy. All participants (13,543 individuals were interviewed and examined by an ophthalmologist for the presence or absence of TT and CO. In addition to field-collected data, remotely sensed climatic data were extracted for each cluster and used to fit Bayesian hierarchical logistic models to disease outcome. The risk of TT/CO was associated with factors at both the individual and cluster levels, with approximately 14% of the total variation attributed to the cluster level. Beyond established individual risk factors (age, gender and occupation, there was strong evidence that environmental/climatic factors at the cluster-level (lower precipitation, higher land surface temperature, higher mean annual temperature and rural classification were also associated with a greater risk of TT/CO. This study establishes the importance of large-scale risk factors in the geographical distribution of TT/CO in Nigeria, supporting anecdotal evidence that environmental conditions are associated

  9. Medicinal management of corneal opacity in free ranging rhesus macaques (Macaca mulatta of Shivalik hills in Western Himalayas, Northern India

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    V. Kumar

    2015-05-01

    Full Text Available Corneal opacification was diagnosed in 17 free ranging rhesus macaques during detailed ophthalmic examination as a part of clinical health examination, at the monkey rescue sterilization centre in Hamirpur Himachal Pradesh, India. The cornea was completely opaque permitting only a little vision with respect to the affected eye. Medical management with topical ciprofloxacin and prednisolone along with ketoprofen and vitamin A was instituted. The corneal lesions subsided completely within one week following treatment. The treatment protocol successfully eliminated the discomfort and intraocular lesions with no serious subsequent irritation due to the treatment in these animals.

  10. Comparison of in vitro eye irritation potential by bovine corneal opacity and permeability (BCOP) assay to erythema scores in human eye sting test of surfactant-based formulations.

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    Cater, Kathleen C; Harbell, John W

    2008-01-01

    The bovine corneal opacity and permeability (BCOP) assay can be used to predict relative eye irritation potential of surfactant-based personal care formulations relative to a corporate benchmark. The human eye sting test is typically used to evaluate product claims of no tears/no stinging for children's bath products. A preliminary investigation was conducted to test a hypothesis that the BCOP assay could be used as a prediction model for relative ranking of human eye irritation responses under conditions of a standard human eye sting test to surfactant-based formulations. BCOP assays and human eye sting tests were conducted on 4 commercial and 1 prototype body wash (BW) developed specifically for children or as mild bath products. In the human eye sting test, 10 mul of a 10% dosing solution is instilled into one eye of each panelist (n = 20), and the contralateral eye is dosed with sterile water as a control. Bulbar conjunctival erythema responses of each eye are graded at 30 seconds by an ophthalmologist. The BCOP assay permeability values (optical density at 490 nm [OD(490)]) for the 5 BWs ranged from 0.438 to 1.252 (i.e., least to most irritating). By comparison, the number of panelists exhibiting erythema responses (mild to moderately pink) ranged from 3 of 20 panelists for the least irritating BW to 10 of 20 panelists for the most irritating BW tested. The relative ranking of eye irritation potential of the 5 BWs in the BCOP assay compares favorably with the relative ranking of the BWs in the human eye sting test. Based on these findings, the permeability endpoint of the BCOP assay, as described for surfactant-based formulations, showed promise as a prediction model for relative ranking of conjunctival erythema responses in the human eye. Consequently, screening of prototype formulations in the BCOP assay would allow for formula optimization of mild bath products prior to investment in a human eye sting test.

  11. SURGICAL OUTCOME OF TRIPLE PROCEDURE AS PENETRATING KERATOPLASTY WITH EXTRACAPSULAR CATARACT EXTRACTION WITH POSTERIOR CHAMBER INTRAOCULAR LENS IMPLANTATION IN PATIENTS WITH BOTH CENTRAL CORNEAL OPACITY AND ADVANCED CATARACT AT RURAL SET UP

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    Shubhangi Nigwekar, Kishor Badhe, Neeta Misra, Surekha Bangal

    2015-10-01

    Full Text Available Purpose: To study the surgical outcome of triple procedure as penetrating keratoplasty (PKP with conventional extra capsular cataract extraction (ECCE with posterior chamber intraocular lens (PCIOL implantation in patients with both central corneal opacity and advanced cataract at rural set up. Introduction: When corneal opacity and cataract present together then well-established and effective triple procedure is indicated. Prognosis for a clear graft is good in triple, as graft endothelium does not touch the hard nucleus which may occur in two steps or sequential surgery. It provides faster visual rehabilitation. Being single step procedure it reduces patient’s hospital stay, postoperative care and follows up visits. Methodology: In this hospital based observational , three years longitudinal study, we studied the surgical outcome of relatively rare one step triple procedure as PKP with conventional ECCE with PCIOL implantation in sulcus or in bag, in patients with both central corneal opacity and advanced cataract at rural set up. The outcome measures included graft clarity on slit lamp, postoperative unaided visual acuity with Snellen’s chart and the occurrence of postoperative complications after taking IEC permission and informed written consent in local language from study patients. Results: Out of 13 study patients mean age was 61.15yrs (Range50-80yrs. Follow up range was 9-34 months. At final follow up 9 patients (69.23% had clear grafts and 61.52% patients gained visual acuity >6/24. Graft failure was the most common post operative complication in 30.76% followed by Posterior capsular opacification (PCO in 15.38% patients which was treated well with YAG laser capsulotomy. Conclusion: Triple procedure gives good results in respect to graft clarity, unaided vision, and faster rehabilitation.

  12. Clinical application of ultrasound biomicroscopy in the treatment of congenital corneal opacities%超声生物显微镜在先天性角膜混浊诊疗中的应用价值

    Institute of Scientific and Technical Information of China (English)

    李东芳; 赵军; 李滢; 臧新杰; 应良

    2012-01-01

    Objective To investigate the clinical application of ultrasound biomicroscopy in the treatment of congenital corneal opacities.Methods Medical records of 20 eyes (15 patients) with congenital corneal opacity treated at our hospital from July 2004 to November 2011 were retrospectively reviewed.Best corrected visual acuity testing,intraocular pressure testing,slit-lamp anterior segment examination,fundus examination,slit-lamp microscopic photography,B scan examination,and ultrasound biomicroscopy were performed for analysis of complications of congenital corneal opacity and selection of surgical approaches.Results The ultrasound biomicroscopic examination showed that 5 eyes had no Descemet's membrane and corneal endothelium,20 eyes had anterior synechia,5 eyes had aniridia,3 eyes had loss of lens cortex,13 eyes had cataract,14 eyes had closed angle,and 3 eyes had pupillary membrane.14 of 20 eyes received surgical treatment,including penetrating keratoplasty combined with cataract extraction and trabeculectomy (5 eyes),penetrating keratoplasty combined with pupil angioplasty (3 eyes),penetrating keratoplasty combined with cataract extraction (3 eyes),penetrating keratoplasty combined with trabeculectomy (2 eyes),and lamellar keratoplasty (1 eye).Conclusions Ultrasound biomicroscopy is important to guide the diagnosis and treatment of congenital corneal opacity.%目的 探讨超声生物显微镜在治疗先天性角膜混浊的临床应用.方法 回顾分析2004年7月至2011年11月于我院收治的先天性角膜混浊患者15例20只眼,常规行最佳矫正视力检查、眼压检查、裂隙灯眼前节检查、眼底检查、大体照相、B型超声检查、超声生物显微镜检查,分析先天性角膜混浊的并发症及手术方式情况.结果 根据超声生物显微镜检查结果,先天性角膜混浊患者伴有角膜无后弹力膜和内皮层者5只眼,虹膜前粘连(Peter异常)者20只眼,虹膜缺损者5只眼,晶体皮质丢失者3

  13. Stellar Opacity

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, F J; Iglesias, C A

    1999-11-07

    The monochromatic opacity, {kappa}{sub v}, quantifies the property of a material to remove energy of frequency v from a radiation field. A harmonic average of {kappa}{sub v}, known as the Rosseland mean, {kappa}{sub R}, is frequently used to simplify the calculation of energy transport in stars. The term ''opacity'' is commonly understood to refer to {kappa}{sub R}. Opacity plays an important role in stellar modeling because for most stars radiation is the primary mechanism for transporting energy from the nuclear burning region in the core to the surface. Depending on the mass, convection and electron thermal conduction can also be important modes of stellar energy transport. The efficiency of energy transport is related to the temperature gradient, which is directly proportional to the mean radiative opacity in radiation dominated regions. When the radiative opacity is large, convection can become the more efficient energy transport mechanism. Electron conductive opacity, the resistance of matter to thermal conduction, is inversely proportional to electron thermal conductivity. Thermal conduction becomes the dominant mode of energy transport at high density and low temperature.

  14. Research on bovine corneal opacity and permeability test integrating with histopathological evaluation%结合组织学评分的牛角膜浑浊和渗透性方法研究

    Institute of Scientific and Technical Information of China (English)

    陈彧; 喻欢; 程树军; 谈伟君; 秦瑶

    2016-01-01

    为了优化替代眼刺激动物试验的牛角膜浑浊和渗透性(BCOP)实验的方法,提高其适用范围和预测性,选取新鲜牛眼角膜,直接暴露液体化学受试物作用10 min,后孵育2 h并用荧光素钠处理90 min,采用浊度仪检测角膜浑浊度,用酶标仪检测荧光素钠渗透性,同时将角膜常规固定和制备组织学切片,观察组织学病理变化并评分,基于上述3个指标建立预测模型。结果显示,将角膜浑浊度和渗透性2个定量指标,与角膜上皮组织、基质组织和内皮细胞的组织学变化评分进行组合,可对轻微刺激到中等刺激的范围进行准确细分。研究表明,结合组织学观察的优化BCOP方法可提高其预测性,适用于眼刺激机制研究和化妆品评估。%In order to refine the alternative method for animal eye irritation test———the bovine corneal opacity and permeability (BCOP)test,and to enhance its application scope and predictability,the fresh bovine corneas were chosen and directly exposed to liquid chemical material to be tested for 10 min,post - incubated for 2 h and further treated with fluorescein sodium for 90 min. Then opacity of the treated corneas was measured with opacitometer;the permeability was determined with the multiskan spectrum microplate spectrophotometer and the histopathological changes of the cornea were observed and graded after routinely fixed and paraffin embedding. Finally,the predictive models based on the above three indices were established. The results showed that the corneal opacity and permeability,integrated with histopathological changes of epithelium, stroma and endothelium,the scope of irritation from mild level to moderate level can be accurately distinguished. In conclusion,the refined BCOP method integrated with histological observation could improve its predictability and suitable for study of eye irritation mechanism and cosmetic product evaluation.

  15. Survey of ocular irritation predictive capacity using Chorioallantoic Membrane Vascular Assay (CAMVA) and Bovine Corneal Opacity and Permeability (BCOP) test historical data for 319 personal care products over fourteen years.

    Science.gov (United States)

    Donahue, D A; Kaufman, L E; Avalos, J; Simion, F A; Cerven, D R

    2011-03-01

    The Chorioallantoic Membrane Vascular Assay (CAMVA) and Bovine Corneal Opacity and Permeability (BCOP) test are widely used to predict ocular irritation potential for consumer-use products. These in vitro assays do not require live animals, produce reliable predictive data for defined applicability domains compared to the Draize rabbit eye test, and are rapid and inexpensive. Data from 304 CAMVA and/or BCOP studies (319 formulations) were surveyed to determine the feasibility of predicting ocular irritation potential for various formulations. Hair shampoos, skin cleansers, and ethanol-based hair styling sprays were repeatedly predicted to be ocular irritants (accuracy rate=0.90-1.00), with skin cleanser and hair shampoo irritation largely dependent on surfactant species and concentration. Conversely, skin lotions/moisturizers and hair styling gels/lotions were repeatedly predicted to be non-irritants (accuracy rate=0.92 and 0.82, respectively). For hair shampoos, ethanol-based hair stylers, skin cleansers, and skin lotions/moisturizers, future ocular irritation testing (i.e., CAMVA/BCOP) can be nearly eliminated if new formulations are systematically compared to those previously tested using a defined decision tree. For other tested product categories, new formulations should continue to be evaluated in CAMVA/BCOP for ocular irritation potential because either the historical data exhibit significant variability (hair conditioners and mousses) or the historical sample size is too small to permit definitive conclusions (deodorants, make-up removers, massage oils, facial masks, body sprays, and other hair styling products). All decision tree conclusions should be made within a conservative weight-of-evidence context, considering the reported limitations of the BCOP test for alcohols, ketones, and solids.

  16. Ocular dimensions, corneal thickness, and corneal curvature in quarter horses with hereditary equine regional dermal asthenia.

    Science.gov (United States)

    Badial, Peres R; Cisneros-Àlvarez, Luis Emiliano; Brandão, Cláudia Valéria S; Ranzani, José Joaquim T; Tomaz, Mayana A R V; Machado, Vania M; Borges, Alexandre S

    2015-09-01

    The aim of this study was to compare ocular dimensions, corneal curvature, and corneal thickness between horses affected with hereditary equine regional dermal asthenia (HERDA) and unaffected horses. Five HERDA-affected quarter horses and five healthy control quarter horses were used. Schirmer's tear test, tonometry, and corneal diameter measurements were performed in both eyes of all horses prior to ophthalmologic examinations. Ultrasonic pachymetry was performed to measure the central, temporal, nasal, dorsal, and ventral corneal thicknesses in all horses. B-mode ultrasound scanning was performed on both eyes of each horse to determine the dimensions of the ocular structures and to calculate the corneal curvature. Each corneal region examined in this study was thinner in the affected group compared with the healthy control group. However, significant differences in corneal thickness were only observed for the central and dorsal regions. HERDA-affected horses exhibited significant increases in corneal curvature and corneal diameter compared with unaffected animals. The ophthalmologic examinations revealed mild corneal opacity in one eye of one affected horse and in both eyes of three affected horses. No significant between-group differences were observed for Schirmer's tear test, intraocular pressure, or ocular dimensions. Hereditary equine regional dermal asthenia-affected horses exhibit decreased corneal thickness in several regions of the cornea, increased corneal curvature, increased corneal diameter, and mild corneal opacity. Additional research is required to determine whether the increased corneal curvature significantly impacts the visual accuracy of horses with HERDA. © 2014 American College of Veterinary Ophthalmologists.

  17. Monocular transparency generates quantitative depth.

    Science.gov (United States)

    Howard, Ian P; Duke, Philip A

    2003-11-01

    Monocular zones adjacent to depth steps can create an impression of depth in the absence of binocular disparity. However, the magnitude of depth is not specified. We designed a stereogram that provides information about depth magnitude but which has no disparity. The effect depends on transparency rather than occlusion. For most subjects, depth magnitude produced by monocular transparency was similar to that created by a disparity-defined depth probe. Addition of disparity to monocular transparency did not improve the accuracy of depth settings. The magnitude of depth created by monocular occlusion fell short of that created by monocular transparency.

  18. Production of a corneal opacity mouse by N-ethyl-N-nitrosourea mutagenesis and chromosome mapping of the mutant gene%乙酰基亚硝基脲诱变的一种角膜混浊小鼠及其突变基因的染色体定位

    Institute of Scientific and Technical Information of China (English)

    陈兵; 糜婷; 倪俊达; 耿滕; 薛整风

    2014-01-01

    背景 乙酰基亚硝基脲(ENU)诱导小鼠基因突变是研究基因功能及建立人类疾病动物模型的一种有效手段. 目的 研究ENU诱变获得的1只角膜混浊小鼠角膜组织形态变化,并对其突变基因进行染色体定位.方法 选用8~10周龄的C57BL/6J (B6)雄鼠40只,腹腔内注射ENU.将注射后的雄鼠与同品系母鼠交配,在其后代小鼠中筛选眼部突变个体,并将突变个体与同品系小鼠配种以确定是否遗传.对ENU诱变获得1只角膜混浊小鼠的角膜行组织病理学观察.繁殖[(B6×D2) F1×B6] N2角膜混浊小鼠,用平均分布于小鼠染色体上的微卫星标记对N2小鼠染色体进行扫描.采用优势对数计分法(LOD)判定突变基因与微卫星是否连锁. 结果 将角膜呈现混浊小鼠与B6背景小鼠配种,在其59只后代中出现19只类似表型的突变小鼠.角膜组织病理学检查发现,该例角膜混浊小鼠角膜基质增厚,出现新生血管和炎性细胞浸润,成纤维细胞明显增多.突变基因与微卫星间的连锁分析发现,26个N2样品中突变基因与位于小鼠2号染色体63.42 cM处的D2Mi307位点发生3例交换,LOD值为3.79,该突变基因位于小鼠第2号染色体. 结论 成功获得角膜混浊小鼠并将其突变基因初步定位于2号染色体,有望为人类角膜混浊疾病研究提供一种新的小鼠模型.%Background N-ethyl-N-nitrosourea (ENU)-induced mouse mutagenesis is a powerful approach for the study of gene function and the generation of human disease models.Objective This study was to create the corneal morphologic change and map the mutant gene of a kind of corneal opacity in ENU mutagenesis in mouse.Methods ENU was intraperitoneally injected in forty C57BL/ 6J (B6) male mice aged 8-10 weeks old.The male mice were mated with the same strain female mice.Their progenies were screened for visible eye mutation,and the mutant mice were mated with the same strain mice to confirm the heredity of

  19. Corneal Laceration

    Medline Plus

    Full Text Available ... Laceration? Corneal Laceration Diagnosis Corneal Laceration Treatment What Is Corneal Laceration? Written By: Daniel Porter Reviewed By: ... A Harrison MD Sep. 01, 2016 The cornea is the clear front window of the eye . A ...

  20. Universe opacity and EBL

    CERN Document Server

    Vavrycuk, Vaclav

    2016-01-01

    The observed extragalactic background light (EBL) is affected by light attenuation due to absorption of light by galactic and intergalactic dust in the Universe. Even galactic opacity of 10-20 percent and minute universe intergalactic opacity of $0.01\\,\\mathrm{mag}\\,h\\,\\mathrm{Gpc}^{-1}$ at the local Universe have a significant impact on the EBL because obscuration of galaxies and density of intergalactic dust increase with redshift as $\\left(1+z\\right)^3$. Consequently, intergalactic opacity increases and the Universe becomes considerably opaque at $z > 3$. Adopting realistic values for galactic and intergalactic opacity, the estimates of the EBL for the expanding dusty universe are close to observations. The luminosity density evolution fits well measurements. The model reproduces a steep increase of the luminosity density at $z3.5$.

  1. Monocular visual ranging

    Science.gov (United States)

    Witus, Gary; Hunt, Shawn

    2008-04-01

    The vision system of a mobile robot for checkpoint and perimeter security inspection performs multiple functions: providing surveillance video, providing high resolution still images, and providing video for semi-autonomous visual navigation. Mid-priced commercial digital cameras support the primary inspection functions. Semi-autonomous visual navigation is a tertiary function whose purpose is to reduce the burden of teleoperation and free the security personnel for their primary functions. Approaches to robot visual navigation require some form of depth perception for speed control to prevent the robot from colliding with objects. In this paper present the initial results of an exploration of the capabilities and limitations of using a single monocular commercial digital camera for depth perception. Our approach combines complementary methods in alternating stationary and moving behaviors. When the platform is stationary, it computes a range image from differential blur in the image stack collected at multiple focus settings. When the robot is moving, it extracts an estimate of range from the camera auto-focus function, and combines this with an estimate derived from angular expansion of a constellation of visual tracking points.

  2. [Regeneration and fibrosis of corneal tissues].

    Science.gov (United States)

    Simirskiĭ, V N

    2014-01-01

    In this review, the features of the regeneration of corneal tissue and its disorders leading to the development of fibrosis are considered. The data on the presence of stem (clonogenic) cell pool in the corneal tissues (epithelium, endothelium, stroma) are given; these cells can serve as a source for regeneration of the tissues at injury or various diseases. The main steps of regeneration of corneal tissues and their disorders that lead to outstripping proliferation of myofibroblasts and secretion of extracellular matrix in the wound area and eventually cause the formation of connective tissue scar and corneal opacity are considered. Particular attention is given to the successes of translational medicine in the treatment of corneal tissue fibrosis. The methods of cell therapy aimed at the restoration of stem cell pool of corneal tissues are the most promising. Gene therapy provides more opportunities; one of its main objectives is the suppression of the myofibroblast proliferation responsible for the development of fibrosis.

  3. Gelatinous drop-like corneal dystrophy: a review.

    Science.gov (United States)

    Kaza, Hrishikesh; Barik, Manas R; Reddy, Mamatha M; Mittal, Ruchi; Das, Sujata

    2017-01-01

    Gelatinous drop-like corneal dystrophy (GDLD) is a rare autosomal recessive form of corneal dystrophy characterised by subepithelial and stromal amyloid deposits. It is relatively common in Japan. It usually presents in the first two decades of life with subepithelial nodular lesions that later coalesce to form mulberry-like opacities. Although various surgical modalities have been attempted, recurrence remains a major challenge.

  4. Corneal Laceration

    Medline Plus

    Full Text Available ... your vision. Privacy Policy Related People with Advanced Keratoconus May Have A Future Alternative to Full Corneal ... 2016 Corneal Collagen Cross-linking Approved to Treat Keratoconus in U.S. Aug 01, 2016 Firework Blinds Teenager, ...

  5. Corneal Laceration

    Medline Plus

    Full Text Available ... lost sight from a corneal scar as a child. Now that I’m older, will a corneal transplant help me? May 15, 2015 Why Do My Eyes Burn After Inserting My Contacts? Feb 27, 2015 Dark ...

  6. Corneal Abrasions

    Science.gov (United States)

    ... and lead to a serious condition called a corneal ulcer . That's why it's important to see a doctor to get a corneal abrasion checked out. What Causes a Corneal ... and land on your cornea, tears help to wash the particles away. Sometimes, ...

  7. [Glycosaminoglycans in subepithelial opacity after excimer laser keratectomy].

    Science.gov (United States)

    Nakayasu, K; Gotoh, T; Ishikawa, T; Kanai, A

    1996-05-01

    We evaluated histochemically the characteristics of glycosaminoglycans and proteoglycans in the corneal subepithelial opacity after excimer laser keratectomy on rabbit corneas. We also performed the same evaluations on the cornea after mechanical keratectomy. Twenty days after the operations, the area immediately subjacent to the epithelium showed strong staining with toluidine blue, alcian blue, and colloidal iron. However, after treatment with chondroitinase ABC or chondroitinase AC, alcian blue staining in this area decreased dramatically. Antilarge proteoglycan antibody also reacted strongly in this area. Histochemical and immunohistochemical examination of the cornea where mechanical keratectomy was done showed basically similar findings with the cornea of excimer laser keratectomy. These results suggest that large-molecula proteoglycans with chondroitine sulfate side chains become localized in the subepithelial area after two different kinds of keratectomies. We presume from histochemical and immunohistochemical observations that the subepithelial opacity observed after excimer laser keratectomy is not a special reaction to excimer laser but simply a corneal scar formed after stromal resection.

  8. Universe opacity and EBL

    Science.gov (United States)

    Vavryčuk, Václav

    2017-02-01

    The observed extragalactic background light (EBL) is affected by light attenuation due to absorption of light by galactic and intergalactic dust in the Universe. Even galactic opacity of 10-20 per cent and minute universe intergalactic opacity of 0.01 mag h Gpc-1 at the local Universe have a significant impact on the EBL because obscuration of galaxies and density of intergalactic dust increase with redshift as (1 + z)3. Consequently, intergalactic opacity increases and the Universe becomes considerably opaque at z > 3. Adopting realistic values for galactic and intergalactic opacity, the estimates of the EBL for the expanding dusty universe are close to observations. The luminosity density evolution fits well measurements. The model reproduces a steep increase of the luminosity density at z EBL ranges from 100 to 200 nW m-2 sr-1 and is within the limits of 40 and 200 nW m-2 sr-1 of current EBL observations. The model predicts 98 per cent of the EBL coming from radiation of galaxies at z 3.5.

  9. Overapplication opacity in phonological acquisition

    Directory of Open Access Journals (Sweden)

    Olga Urek

    2013-02-01

    Full Text Available Normal 0 false false false EN-US JA X-NONE Phonological opacity is a challenge for parallel OT, which does not allow for intermediate levels of representation. Several modifications of the theory have been proposed over the years to incorporate opacity, all of them falling short of accounting for spontaneous opacity effects in developing grammars. In this paper I demonstrate that if certain independently motivated adjustments are made to the recent OT-based theory of opacity called Optimality Theory with Candidate Chains (OT-CC, see McCarthy 2007, it can successfully deal with spontaneous opacity effects.

  10. Molecular opacities for exoplanets.

    Science.gov (United States)

    Bernath, Peter F

    2014-04-28

    Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanets are reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Molecular opacities needed to simulate astronomical observations can be obtained from laboratory measurements, ab initio calculations or a combination of the two approaches. This discussion article focuses mainly on laboratory measurements of hot molecules as needed for exoplanet spectroscopy.

  11. Corneal Laceration

    Science.gov (United States)

    ... drugs. These drugs thin the blood and may increase bleeding. After you have finished protecting the eye, see a physician immediately. Next Corneal Laceration Symptoms Related Ask an Ophthalmologist Answers I lost sight from a corneal scar as a child. Now that I’m older, ...

  12. Corneal Laceration

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Corneal Laceration ... Laceration Treatment What Is Corneal Laceration? Leer en Español: ¿Qué Es una Laceración de la Córnea? Written ...

  13. Corneal Laceration

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    Full Text Available ... Health Find an Ophthalmologist Academy Store Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask ... Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Corneal Laceration Sections What Is Corneal Laceration? ...

  14. Corneal Laceration

    Medline Plus

    Full Text Available ... Health Find an Ophthalmologist Academy Store Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask ... Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Corneal Laceration Sections What Is Corneal Laceration? ...

  15. The molecular genetics of the corneal dystrophies--current status.

    Science.gov (United States)

    Klintworth, Gordon K

    2003-05-01

    The pertinent literature on inherited corneal diseases is reviewed in terms of the chromosomal localization and identification of the responsible genes. Disorders affecting the cornea have been mapped to human chromosome 1 (central crystalline corneal dystrophy, familial subepithelial corneal amyloidosis, early onset Fuchs dystrophy, posterior polymorphous corneal dystrophy), chromosome 4 (Bietti marginal crystalline dystrophy), chromosome 5 (lattice dystrophy types 1 and IIIA, granular corneal dystrophy types 1, 2 and 3, Thiel-Behnke corneal dystrophy), chromosome 9 (lattice dystrophy type II), chromosome 10 (Thiel-Behnke corneal dystrophy), chromosome 12 (Meesmann dystrophy), chromosome 16 (macular corneal dystrophy, fish eye disease, LCAT disease, tyrosinemia type II), chromosome 17 (Meesmann dystrophy, Stocker-Holt dystrophy), chromosome 20 (congenital hereditary endothelial corneal dystrophy types I and II, posterior polymorphous corneal dystrophy), chromosome 21 (autosomal dominant keratoconus) and the X chromosome (cornea verticillata, cornea farinata, deep filiform corneal dystrophy, keratosis follicularis spinulosa decalvans, Lisch corneal dystrophy). Mutations in nine genes (ARSC1, CHST6, COL8A2, GLA, GSN, KRT3, KRT12, M1S1and TGFBI [BIGH3]) account for some of the corneal diseases and three of them are associated with amyloid deposition in the cornea (GSN, M1S1, TGFBI) including most of the lattice corneal dystrophies (LCDs) [LCD types I, IA, II, IIIA, IIIB, IV, V, VI and VII] recognized by their lattice pattern of linear opacities. Genetic studies on inherited diseases affecting the cornea have provided insight into some of these disorders at a basic molecular level and it has become recognized that distinct clinicopathologic phenotypes can result from specific mutations in a particular gene, as well as some different mutations in the same gene. A molecular genetic understanding of inherited corneal diseases is leading to a better appreciation of the

  16. Indocyanine green staining for the triple corneal procedure.

    Science.gov (United States)

    Kobayashi, Akira; Segawa, Yoji; Nishimura, Akira; Shirao, Yutaka; Sugiyama, Kazuhisa

    2004-01-01

    In the triple corneal procedure, successful completion of capsulorhexis is of the utmost importance. Another use of indocyanine green dye for better visualization of the anterior lens capsule of mature cataract during the triple corneal procedure is described. Four consecutive patients (mean age, 69.5 years) with both mature cataracts and corneal opacity underwent the triple corneal procedure. After trephination of the recipient cornea, the anterior capsule of the lens was stained with indocyanine green. A continuous curvilinear capsulorhexis (CCC) was performed, after which conventional triple corneal procedures were followed. In all four cases, this technique markedly improved visualization of the lens capsule and resulted in successful and easy manipulation of the CCC and subsequent removal of residual lens cortex. Staining of the anterior capsule of mature cataract in the triple corneal procedure clearly defines the border of the capsule, thus allowing easy and complete execution of CCC.

  17. Corneal Laceration

    Medline Plus

    Full Text Available ... from Laundry Packets On the Rise Jun 30, 2017 People with Advanced Keratoconus May Have A Future Alternative to Full Corneal Transplantation Nov 29, 2016 Combating Eye Injuries from Air Guns Aug 30, ...

  18. Corneal transplant

    Science.gov (United States)

    ... lenses to achieve the best vision. Laser vision correction may be an option if you have nearsightedness, ... Editorial team. Related MedlinePlus Health Topics Corneal Disorders Refractive Errors Browse the Encyclopedia A.D.A.M., Inc. ...

  19. Corneal Laceration

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    Full Text Available ... Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide ... What Is Corneal Laceration? Leer en Español: ¿Qué ...

  20. Corneal Laceration

    Medline Plus

    Full Text Available ... itself. A corneal laceration is a very serious injury and requires immediate medical attention to avoid severe ... Dangerous for Your Eyes Sep 20, 2017 Eye Injuries from Laundry Packets On the Rise Jun 30, ...

  1. Corneal Laceration

    Medline Plus

    Full Text Available ... itself. A corneal laceration is a very serious injury and requires immediate medical attention to avoid severe ... 27, 2015 Dark Spot in Vision After Blunt Trauma Dec 21, 2014 Pain a Year After Eyelid ...

  2. Corneal Laceration

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    Full Text Available ... itself. A corneal laceration is a very serious injury and requires immediate medical attention to avoid severe ... and preserving your vision. Privacy Policy Related Eye Injuries from Laundry Packets On the Rise Jun 30, ...

  3. Corneal Laceration

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    Full Text Available ... 2017 People with Advanced Keratoconus May Have A Future Alternative to Full Corneal Transplantation Nov 29, 2016 Combating Eye Injuries from Air Guns Aug 30, ... Public & Patients: Contact Us About ...

  4. Corneal Laceration

    Medline Plus

    Full Text Available ... by something sharp flying into the eye. It can also be caused by something striking the eye ... If the corneal laceration is deep enough it can cause a full thickness laceration. This is when ...

  5. Corneal Laceration

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    Full Text Available ... Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide ... What Is Corneal Laceration? Written By: Daniel Porter ...

  6. Corneal Laceration

    Medline Plus

    Full Text Available ... By: Devin A Harrison MD Sep. 01, 2017 The cornea is the clear front window of the eye . A corneal laceration is a cut on the cornea. It is usually caused by something sharp ...

  7. Corneal Laceration

    Medline Plus

    Full Text Available ... itself. A corneal laceration is a very serious injury and requires immediate medical attention to avoid severe ... 27, 2015 Dark Spot in Vision After Blunt Trauma Dec 21, 2014 Pain a Year After Eyelid ...

  8. Validation of Data Association for Monocular SLAM

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2013-01-01

    Full Text Available Simultaneous Mapping and Localization (SLAM is a multidisciplinary problem with ramifications within several fields. One of the key aspects for its popularity and success is the data fusion produced by SLAM techniques, providing strong and robust sensory systems even with simple devices, such as webcams in Monocular SLAM. This work studies a novel batch validation algorithm, the highest order hypothesis compatibility test (HOHCT, against one of the most popular approaches, the JCCB. The HOHCT approach has been developed as a way to improve performance of the delayed inverse-depth initialization monocular SLAM, a previously developed monocular SLAM algorithm based on parallax estimation. Both HOHCT and JCCB are extensively tested and compared within a delayed inverse-depth initialization monocular SLAM framework, showing the strengths and costs of this proposal.

  9. Monocular Elevation Deficiency - Double Elevator Palsy

    Science.gov (United States)

    ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ...

  10. Monocular indoor localization techniques for smartphones

    Directory of Open Access Journals (Sweden)

    Hollósi Gergely

    2016-12-01

    Full Text Available In the last decade huge research work has been put to the indoor visual localization of personal smartphones. Considering the available sensor capabilities monocular odometry provides promising solution, even reecting requirements of augmented reality applications. This paper is aimed to give an overview of state-of-the-art results regarding monocular visual localization. For this purpose essential basics of computer vision are presented and the most promising solutions are reviewed.

  11. First Identification of a Triple Corneal Dystrophy Association: Keratoconus, Epithelial Basement Membrane Corneal Dystrophy and Fuchs' Endothelial Corneal Dystrophy

    Directory of Open Access Journals (Sweden)

    Cosimo Mazzotta

    2014-09-01

    Full Text Available Purpose: To report the observation of a triple corneal dystrophy association consisting of keratoconus (KC, epithelial basement membrane corneal dystrophy (EBMCD and Fuchs' endothelial corneal dystrophy (FECD. Methods: A 55-year-old male patient was referred to our cornea service for blurred vision and recurrent foreign body sensation. He reported bilateral recurrent corneal erosions with diurnal visual fluctuations. He underwent corneal biomicroscopy, Scheimpflug tomography, in vivo HRT confocal laser scanning microscopy and genetic testing for TGFBI and ZEB1 mutations using direct DNA sequencing. Results: Biomicroscopic examination revealed the presence of subepithelial central and paracentral corneal opacities. The endothelium showed a bilateral flecked appearance, and the posterior corneal curvature suggested a possible concomitant ectatic disorder. Corneal tomography confirmed the presence of a stage II KC in both eyes. In vivo confocal laser scanning microscopy revealed a concomitant bilateral EBMCD with hyperreflective deposits in basal epithelial cells, subbasal Bowman's layer microfolds and ridges with truncated subbasal nerves as pseudodendritic elements. Stromal analysis revealed honeycomb edematous areas, and the endothelium showed a strawberry surface configuration typical of FECD. The genetic analysis resulted negative for TGFBI mutations and positive for a heterozygous mutation in exon 7 of the gene ZEB1. Conclusion: This is the first case reported in the literature in which KC, EBMCD and FECD are present in the same patient and associated with ZEB1 gene mutation. The triple association was previously established by means of morphological analysis of the cornea using corneal Scheimpflug tomography and in vivo HRT II confocal laser scanning microscopy.

  12. A comparison between keratoconus and normal population based corneal endothelium

    Directory of Open Access Journals (Sweden)

    Mohamad Aghazade Amiri

    2015-07-01

    Conclusion: Keratoconus does not have any considerable effect on cell density, polymegethism and pleomorphism, in mild and moderate stages and corneal opacity risk caused by intraocular surgeries (such as: Cataract or Glaucoma surgeries and some diseases (such as diabetes and uveitis is similar in keratoconic and normal eyes.

  13. Monocular Video Guided Garment Simulation

    Institute of Scientific and Technical Information of China (English)

    Fa-Ming Li; Xiao-Wu Chen∗; Bin Zhou; Fei-Xiang Lu; Kan Guo; Qiang Fu

    2015-01-01

    We present a prototype to generate a garment-shape sequence guided by a monocular video sequence. It is a combination of a physically-based simulation and a boundary-based modification. Given a garment in the video worn on a mannequin, the simulation generates a garment initial shape by exploiting the mannequin shapes estimated from the video. The modification then deforms the simulated 3D shape into such a shape that matches the garment 2D boundary extracted from the video. According to the matching correspondences between the vertices on the shape and the points on the boundary, the modification is implemented by attracting the matched vertices and their neighboring vertices. For best-matching correspondences and efficient performance, three criteria are introduced to select the candidate vertices for matching. Since modifying each garment shape independently may cause inter-frame oscillations, changes by the modification are also propagated from one frame to the next frame. As a result, the generated garment 3D shape sequence is stable and similar to the garment video sequence. We demonstrate the effectiveness of our prototype with a number of examples.

  14. Corneal Transplantation

    DEFF Research Database (Denmark)

    Hjortdal, Jesper Østergaard

    Corneal transplantation has been performed for more than 100 years. Until 15 years ago the state-of-the art type of transplantation was penetrating keratoplasty, but since the start of this millennium, newly designed surgical techniques have developed considerably. Today, the vast majority of ker...

  15. Corneal Laceration

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Corneal Laceration ... After Eyelid Scratch Jul 28, 2014 Leer en Español: ¿Qué Es una Laceración de la Córnea? Find ...

  16. Corneal topography

    DEFF Research Database (Denmark)

    Andersen, J.; Koch-Jensen, P.; Østerby, Ole

    1993-01-01

    The central corneal zone is depicted on keratoscope photographs using a small target aperture and a large object distance. Information on the peripheral area is included by employing a hemispherical target with a dense circular and radial pattern. On a 16 mm (R = 8 mm) reference steel sphere...

  17. Corneal chromoblastomycosis.

    Science.gov (United States)

    Barton, K; Miller, D; Pflugfelder, S C

    1997-03-01

    We sought to illustrate the difficulty in managing uncommon, pigmented mold-related corneal ulceration and to highlight the role of itraconazole in treating these patients. We describe the management and clinical course of a patient with a recurring corneal infection caused by Fonsecaea pedrosoi and discuss this experience in the light of existing literature on management of cutaneous chromoblastomycosis. A corneal ulcer caused by this organism healed initially on treatment with topical and systemic antifungal medication, but infection recurred in the deep stroma 4 months after cessation of therapy. After failure to respond to a further period of medical therapy, a small therapeutic penetrating keratoplasty was performed. Culture of a fibrinous membrane from the anterior iris surface demonstrated intraocular fungal infection, and postoperatively, an episode of marked fibrinous uveitis developed, suggesting the presence of viable intraocular fungal elements. A large penetrating keratoplasty was therefore performed with excision of involved iris in combination with extracapsular cataract extraction. F. pedrosoi was again cultured from the fibrinous membrane adherent to the iris and from the anterior lens capsule. Postoperatively the patient received a 5-month course of systemic itraconazole, and no further recurrences have been encountered after a further 2 months. F. pedrosoi is the organism most commonly isolated from the chronic cutaneous mycosis, chromoblastomycosis, and is relatively resistant to medical therapy. As has been reported for cutaneous disease, surgery in combination with systemic itraconazole may provide the best chance of cure in corneal chromoblastomycosis.

  18. Enhancing OPAC Records for Discovery

    Directory of Open Access Journals (Sweden)

    Patrick Griffis

    2009-09-01

    Full Text Available This article proposes adding keywords and descriptors to the catalog records of electronic databases and media items to enhance their discovery. The authors contend that subject liaisons can add value to OPAC records and enhance discovery of electronic databases and media items by providing searchable keywords and resource descriptions. The authors provide an examination of OPAC records at their own library, which illustrates the disparity of useful keywords and descriptions within the notes field for media item records versus electronic database records. The authors outline methods for identifying useful keywords for indexing OPAC records of electronic databases. Also included is an analysis of the advantages of using Encore’s Community Tag and Community Review features to allow subject liaisons to work directly in the catalog instead of collaborating with cataloging staff

  19. Feline corneal disease.

    Science.gov (United States)

    Moore, Phillip Anthony

    2005-05-01

    The cornea is naturally transparent. Anything that interferes with the cornea's stromal architecture, contributes to blood vessel migration, increases corneal pigmentation, or predisposes to corneal edema, disrupts the corneas transparency and indicates corneal disease. The color, location, and shape and pattern of a corneal lesion can help in determining the underlying cause for the disease. Corneal disease is typically divided into congenital or acquired disorders. Congenital disorders, such as corneal dermoids are rare in cats, whereas acquired corneal disease associated with nonulcerative or ulcerative keratitis is common. Primary ocular disease, such as tear film instability, adenexal disease (medial canthal entropion, lagophthalmus, eyelid agenesis), and herpes keratitis are associated with the majority of acquired corneal disease in cats. Proliferative/eosinophilic keratitis, acute bullous keratopathy, and Florida keratopathy are common feline nonulcerative disorders. Nonprogressive ulcerative disease in cats, such as chronic corneal epithelial defects and corneal sequestration are more common than progressive corneal ulcerations.

  20. Monocular Blindness: Is It a Handicap?

    Science.gov (United States)

    Knoth, Sharon

    1995-01-01

    Students with monocular vision may be in need of special assistance and should be evaluated by a multidisciplinary team to determine whether the visual loss is affecting educational performance. This article discusses the student's eligibility for special services, difficulty in performing depth perception tasks, difficulties in specific classroom…

  1. Disparity biasing in depth from monocular occlusions.

    Science.gov (United States)

    Tsirlin, Inna; Wilcox, Laurie M; Allison, Robert S

    2011-07-15

    Monocular occlusions have been shown to play an important role in stereopsis. Among other contributions to binocular depth perception, monocular occlusions can create percepts of illusory occluding surfaces. It has been argued that the precise location in depth of these illusory occluders is based on the constraints imposed by occlusion geometry. Tsirlin et al. (2010) proposed that when these constraints are weak, the depth of the illusory occluder can be biased by a neighboring disparity-defined feature. In the present work we test this hypothesis using a variety of stimuli. We show that when monocular occlusions provide only partial constraints on the magnitude of depth of the illusory occluders, the perceived depth of the occluders can be biased by disparity-defined features in the direction unrestricted by the occlusion geometry. Using this disparity bias phenomenon we also show that in illusory occluder stimuli where disparity information is present, but weak, most observers rely on disparity while some use occlusion information instead to specify the depth of the illusory occluder. Taken together our experiments demonstrate that in binocular depth perception disparity and monocular occlusion cues interact in complex ways to resolve perceptual ambiguity. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Does monocular visual space contain planes?

    NARCIS (Netherlands)

    Koenderink, J.J.; Albertazzi, L.; Doorn, A.J. van; Ee, R. van; Grind, W.A. van de; Kappers, A.M.L.; Lappin, J.S.; Norman, J.F.; Oomes, A.H.J.; Pas, S.F. te; Phillips, F.; Pont, S.C.; Richards, W.A.; Todd, J.T.; Verstraten, F.A.J.; Vries, S.C. de

    2010-01-01

    The issue of the existence of planes—understood as the carriers of a nexus of straight lines—in the monocular visual space of a stationary human observer has never been addressed. The most recent empirical data apply to binocular visual space and date from the 1960s (Foley, 1964). This appears to be

  3. Recovery of neurofilament following early monocular deprivation

    Directory of Open Access Journals (Sweden)

    Timothy P O'Leary

    2012-04-01

    Full Text Available A brief period of monocular deprivation in early postnatal life can alter the structure of neurons within deprived-eye-receiving layers of the dorsal lateral geniculate nucleus. The modification of structure is accompanied by a marked reduction in labeling for neurofilament, a protein that composes the stable cytoskeleton and that supports neuron structure. This study examined the extent of neurofilament recovery in monocularly deprived cats that either had their deprived eye opened (binocular recovery, or had the deprivation reversed to the fellow eye (reverse occlusion. The degree to which recovery was dependent on visually-driven activity was examined by placing monocularly deprived animals in complete darkness (dark rearing. The loss of neurofilament and the reduction of soma size caused by monocular deprivation were both ameliorated equally following either binocular recovery or reverse occlusion for 8 days. Though monocularly deprived animals placed in complete darkness showed recovery of soma size, there was a generalized loss of neurofilament labeling that extended to originally non-deprived layers. Overall, these results indicate that recovery of soma size is achieved by removal of the competitive disadvantage of the deprived eye, and occurred even in the absence of visually-driven activity. Recovery of neurofilament occurred when the competitive disadvantage of the deprived eye was removed, but unlike the recovery of soma size, was dependent upon visually-driven activity. The role of neurofilament in providing stable neural structure raises the intriguing possibility that dark rearing, which reduced overall neurofilament levels, could be used to reset the deprived visual system so as to make it more ameliorable with treatment by experiential manipulations.

  4. Equine corneal stromal abscesses

    DEFF Research Database (Denmark)

    Henriksen, M. D. L.; Andersen, P. H.; Plummer, C. E.

    2013-01-01

    The last 30 years have seen many changes in the understanding of the pathogenesis and treatment of equine corneal stromal abscesses (SAs). Stromal abscesses were previously considered an eye problem related to corneal bacterial infection, equine recurrent uveitis, corneal microtrauma and corneal...

  5. Crystalline Subtype of Pre-Descemetic Corneal Dystrophy

    Directory of Open Access Journals (Sweden)

    Rosa Dolz-Marco

    2014-01-01

    Full Text Available Purpose: To report corneal findings in a familial case of the crystalline subtype of pre- Descemetic corneal dystrophy. Case Report: A 19-year-old girl and her 44-year-old mother were found to have asymptomatic, bilateral, punctiform and multi-colored crystalline opacities across the whole posterior layer of the corneas. Endothelial specular microscopy revealed the presence of white round flecks located at different levels anterior to the endothelium. No systemic abnormalities or medications could be related to account for these findings. Conclusion: To the best of our knowledge, this is the third familial report of this rare corneal disorder. Differential diagnosis may include Schnyder corneal dystrophy, cystinosis, Bietti΄s dystrophy and monoclonal gammopathy.

  6. Iron opacity experiments for the solar interior

    Science.gov (United States)

    Nagayama, T.; Bailey, J. E.; Loisel, G.; Rochau, G. A.; Hansen, S. B.; Blancard, C.; Cosse, Ph.; Faussurier, G.; Gilleron, F.; Pain, J.-C.; Pradhan, A. K.; Orban, C.; Pinsonneault, M.; Nahar, S. N.; Iglesias, C. A.; Wilson, B.; Colgan, J.; Fontes, C.; Kilcrease, D.; Sherrill, M.; Macfarlane, J. J.; Golovkin, I.; Mancini, R. C.

    2014-10-01

    Iron opacity experiments near solar interior conditions are performed at SNL Z-machine to better constrain solar models. The SNL opacity science platform satisfies the many challenging requirements for opacity measurements and successfully determines iron opacities at multiple conditions. We found that the agreement between the modeled opacity and the measured opacity deteriorates as Te and ne are raised to approach solar interior conditions. While the inaccuracy of the modeled opacity partially resolves the solar abundance problem, the announcement of such discrepancies has a high impact on the astrophysics, atomic physics, and high energy density physics, and thus more scrutiny on the potential experimental flaws is critical. We report the synthetic investigation for potential sources of systematic uncertainties in the experiments. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

  7. A new, band-shaped and whorled microcystic dystrophy of the corneal epithelium.

    Science.gov (United States)

    Lisch, W; Steuhl, K P; Lisch, C; Weidle, E G; Emmig, C T; Cohen, K L; Perry, H D

    1992-07-15

    Five family members and three unrelated patients (four women, four men, 23 to 71 years old) had a dystrophy of the corneal epithelium. Direct slit-lamp examination showed bilateral or unilateral, gray, band-shaped, and feathery opacities that sometimes appeared in whorled patterns. Retroillumination showed intraepithelial, densely crowded, clear microcysts. Light and electron microscopy disclosed diffuse vacuolization of the cytoplasm of epithelial cells in the affected area. Visual acuity was so reduced in three patients that abrasion of the corneal epithelium was performed. The corneal abnormalities recurred within months, with the same reduction in visual acuity as before. The corneal opacities were progressive in two patients but diminished noticeably in another after he began using a hard contact lens. We found no other ophthalmic irregularities or associated systemic abnormalities and no indication of drug-induced keratopathy.

  8. Monocular and binocular depth discrimination thresholds.

    Science.gov (United States)

    Kaye, S B; Siddiqui, A; Ward, A; Noonan, C; Fisher, A C; Green, J R; Brown, M C; Wareing, P A; Watt, P

    1999-11-01

    Measurement of stereoacuity at varying distances, by real or simulated depth stereoacuity tests, is helpful in the evaluation of patients with binocular imbalance or strabismus. Although the cue of binocular disparity underpins stereoacuity tests, there may be variable amounts of other binocular and monocular cues inherent in a stereoacuity test. In such circumstances, a combined monocular and binocular threshold of depth discrimination may be measured--stereoacuity conventionally referring to the situation where binocular disparity giving rise to retinal disparity is the only cue present. A child-friendly variable distance stereoacuity test (VDS) was developed, with a method for determining the binocular depth threshold from the combined monocular and binocular threshold of depth of discrimination (CT). Subjects with normal binocular function, reduced binocular function, and apparently absent binocularity were included. To measure the threshold of depth discrimination, subjects were required by means of a hand control to align two electronically controlled spheres at viewing distances of 1, 3, and 6m. Stereoacuity was also measured using the TNO, Frisby, and Titmus stereoacuity tests. BTs were calculated according to the function BT= arctan (1/tan alphaC - 1/tan alphaM)(-1), where alphaC and alphaM are the angles subtended at the nodal points by objects situated at the monocular threshold (alphaM) and the combined monocular-binocular threshold (alphaC) of discrimination. In subjects with good binocularity, BTs were similar to their combined thresholds, whereas subjects with reduced and apparently absent binocularity had binocular thresholds 4 and 10 times higher than their combined thresholds (CT). The VDS binocular thresholds showed significantly higher correlation and agreement with the TNO test and the binocular thresholds of the Frisby and Titmus tests, than the corresponding combined thresholds (p = 0.0019). The VDS was found to be an easy to use real depth

  9. Quantitative perceived depth from sequential monocular decamouflage.

    Science.gov (United States)

    Brooks, K R; Gillam, B J

    2006-03-01

    We present a novel binocular stimulus without conventional disparity cues whose presence and depth are revealed by sequential monocular stimulation (delay > or = 80 ms). Vertical white lines were occluded as they passed behind an otherwise camouflaged black rectangular target. The location (and instant) of the occlusion event, decamouflaging the target's edges, differed in the two eyes. Probe settings to match the depth of the black rectangular target showed a monotonic increase with simulated depth. Control tests discounted the possibility of subjects integrating retinal disparities over an extended temporal window or using temporal disparity. Sequential monocular decamouflage was found to be as precise and accurate as conventional simultaneous stereopsis with equivalent depths and exposure durations.

  10. Monocular depth effects on perceptual fading.

    Science.gov (United States)

    Hsu, Li-Chuan; Kramer, Peter; Yeh, Su-Ling

    2010-08-06

    After prolonged viewing, a static target among moving non-targets is perceived to repeatedly disappear and reappear. An uncrossed stereoscopic disparity of the target facilitates this Motion-Induced Blindness (MIB). Here we test whether monocular depth cues can affect MIB too, and whether they can also affect perceptual fading in static displays. Experiment 1 reveals an effect of interposition: more MIB when the target appears partially covered by, than when it appears to cover, its surroundings. Experiment 2 shows that the effect is indeed due to interposition and not to the target's contours. Experiment 3 induces depth with the watercolor illusion and replicates Experiment 1. Experiments 4 and 5 replicate Experiments 1 and 3 without the use of motion. Since almost any stimulus contains a monocular depth cue, we conclude that perceived depth affects perceptual fading in almost any stimulus, whether dynamic or static. Copyright 2010 Elsevier Ltd. All rights reserved.

  11. Monocular Vision SLAM for Indoor Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Koray Çelik

    2013-01-01

    Full Text Available This paper presents a novel indoor navigation and ranging strategy via monocular camera. By exploiting the architectural orthogonality of the indoor environments, we introduce a new method to estimate range and vehicle states from a monocular camera for vision-based SLAM. The navigation strategy assumes an indoor or indoor-like manmade environment whose layout is previously unknown, GPS-denied, representable via energy based feature points, and straight architectural lines. We experimentally validate the proposed algorithms on a fully self-contained microaerial vehicle (MAV with sophisticated on-board image processing and SLAM capabilities. Building and enabling such a small aerial vehicle to fly in tight corridors is a significant technological challenge, especially in the absence of GPS signals and with limited sensing options. Experimental results show that the system is only limited by the capabilities of the camera and environmental entropy.

  12. Induction of corneal collagen cross-linking in experimental corneal alkali burns in rabbits

    Directory of Open Access Journals (Sweden)

    Marcello Colombo-Barboza

    2014-10-01

    Full Text Available Objective: To evaluate the effect of riboflavin-ultraviolet-A-induced cross-linking (CXL following corneal alkali burns in rabbits. Methods: The right corneas and limbi of ten rabbits were burned using a 1N solution of NaOH and the animals were then divided into two groups: a control group submitted to clinical treatment alone and an experimental group that was treated 1 h after injury with CXL, followed by the same clinical treatment as administered to the controls. Clinical parameters were evaluated post-injury at 1, 7, 15, and 30 days by two independent observers. Following this evaluation, the corneas were excised and examined histologically. Results: There were no statistically significant differences in clinical parameters, such as hyperemia, corneal edema, ciliary injection, limbal ischemia, secretion, corneal neovascularization, symblepharon, or blepharospasm, at any of the time-points evaluated. However, the size of the epithelial defect was significantly smaller in the CXL group (p<0.05 (day 15: p=0.008 and day 30: p=0.008 and the extent of the corneal injury (opacity lesion was also smaller (day 30: p=0.021. Histopathology showed the presence of collagen bridges linking the collagen fibers in only the CXL group. Conclusions: These results suggest that the use of CXL may improve the prognosis of acute corneal alkali burns.

  13. Outdoor autonomous navigation using monocular vision

    OpenAIRE

    Royer, Eric; Bom, Jonathan; Dhome, Michel; Thuilot, Benoît; Lhuillier, Maxime; Marmoiton, Francois

    2005-01-01

    International audience; In this paper, a complete system for outdoor robot navigation is presented. It uses only monocular vision. The robot is first guided on a path by a human. During this learning step, the robot records a video sequence. From this sequence, a three dimensional map of the trajectory and the environment is built. When this map has been computed, the robot is able to follow the same trajectory by itself. Experimental results carried out with an urban electric vehicle are sho...

  14. Line Broadening and the Solar Opacity Problem

    Science.gov (United States)

    Krief, M.; Feigel, A.; Gazit, D.

    2016-06-01

    The calculation of line widths constitutes theoretical and computational challenges in the calculation of opacities of hot, dense plasmas. Opacity models use line broadening approximations that are untested at stellar interior conditions. Moreover, calculations of atomic spectra of the Sun indicate a large discrepancy in the K-shell line widths between several atomic codes and the Opacity-Project (OP). In this work, the atomic code STAR is used to study the sensitivity of solar opacities to line broadening. Variations in the solar opacity profile due to an increase of the Stark widths resulting from discrepancies with OP, are compared, in light of the solar opacity problem, with the required opacity variations of the present day Sun, as imposed by helioseismic and neutrino observations. The resulting variation profile is much larger than the discrepancy between different atomic codes, agrees qualitatively with the missing opacity profile, recovers about half of the missing opacity nearby the convection boundary, and has a little effect in the internal regions. Since it is hard to estimate quantitatively the uncertainty in the Stark widths, we show that an increase of all line widths by a factor of about ˜100 recovers quantitatively the missing opacity. These results emphasize the possibility that photoexcitation processes are not modeled properly, and more specifically, highlight the need for a better theoretical characterization of the line broadening phenomena at stellar interior conditions, and of the uncertainty due to the way it is implemented by atomic codes.

  15. Monocular alignment in different depth planes.

    Science.gov (United States)

    Shimono, Koichi; Wade, Nicholas J

    2002-04-01

    We examined (a) whether vertical lines at different physical horizontal positions in the same eye can appear to be aligned, and (b), if so, whether the difference between the horizontal positions of the aligned vertical lines can vary with the perceived depth between them. In two experiments, each of two vertical monocular lines was presented (in its respective rectangular area) in one field of a random-dot stereopair with binocular disparity. In Experiment 1, 15 observers were asked to align a line in an upper area with a line in a lower area. The results indicated that when the lines appeared aligned, their horizontal physical positions could differ and the direction of the difference coincided with the type of disparity of the rectangular areas; this is not consistent with the law of the visual direction of monocular stimuli. In Experiment 2, 11 observers were asked to report relative depth between the two lines and to align them. The results indicated that the difference of the horizontal position did not covary with their perceived relative depth, suggesting that the visual direction and perceived depth of the monocular line are mediated via different mechanisms.

  16. Visual SLAM for Handheld Monocular Endoscope.

    Science.gov (United States)

    Grasa, Óscar G; Bernal, Ernesto; Casado, Santiago; Gil, Ismael; Montiel, J M M

    2014-01-01

    Simultaneous localization and mapping (SLAM) methods provide real-time estimation of 3-D models from the sole input of a handheld camera, routinely in mobile robotics scenarios. Medical endoscopic sequences mimic a robotic scenario in which a handheld camera (monocular endoscope) moves along an unknown trajectory while observing an unknown cavity. However, the feasibility and accuracy of SLAM methods have not been extensively validated with human in vivo image sequences. In this work, we propose a monocular visual SLAM algorithm tailored to deal with medical image sequences in order to provide an up-to-scale 3-D map of the observed cavity and the endoscope trajectory at frame rate. The algorithm is validated over synthetic data and human in vivo sequences corresponding to 15 laparoscopic hernioplasties where accurate ground-truth distances are available. It can be concluded that the proposed procedure is: 1) noninvasive, because only a standard monocular endoscope and a surgical tool are used; 2) convenient, because only a hand-controlled exploratory motion is needed; 3) fast, because the algorithm provides the 3-D map and the trajectory in real time; 4) accurate, because it has been validated with respect to ground-truth; and 5) robust to inter-patient variability, because it has performed successfully over the validation sequences.

  17. Corneal ulcers in horses.

    Science.gov (United States)

    Williams, Lynn B; Pinard, Chantale L

    2013-01-01

    Corneal ulceration is commonly diagnosed by equine veterinarians. A complete ophthalmic examination as well as fluorescein staining, corneal cytology, and corneal bacterial (aerobic) and fungal culture and sensitivity testing are necessary for all infected corneal ulcers. Appropriate topical antibiotics, topical atropine, and systemic NSAIDs are indicated for all corneal ulcers. If keratomalacia (melting) is observed, anticollagenase/antiprotease therapy, such as autologous serum, is indicated. If fungal infection is suspected, antifungal therapy is a necessity. Subpalpebral lavage systems allow convenient, frequent, and potentially long-term therapy. Referral corneal surgeries provide additional therapeutic options when the globe's integrity is threatened or when improvement has not been detected after appropriate therapy.

  18. Corneal transplant - discharge

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000243.htm Corneal transplant - discharge To use the sharing features on this page, please enable JavaScript. You had a corneal transplant. Most of the tissue of your cornea (the ...

  19. Analytical opacity formulas for low Z plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rubiano, J; Rodriguez, R; Gil, J M; Florido, R; Martel, P; Mendoza, M A; Suarez, D [Departamento de FIasica, Universidad de Las Palmas de GC, 35017 Las Palmas de GC (Spain); Minguez, E [Instituto de Fusion Nuclear DENIM. Universidad Politecnica de Madrid, 28019 Madrid (Spain)], E-mail: jgarcia@dfis.ulpgc.es

    2008-05-01

    The accurate computation of radiative opacities is basic in the ICF target physics analysis, in which the radiation is an important feature to determine in detail. For this reason, accurate analytical formulas for giving mean opacities versus temperature and density of the plasma seem to be a useful tool. In this work we analyse some analytical expressions found in the literature for the opacity low Z plasmas in a wide range of temperature and densities. The validity of these formulas for computing the opacity under NLTE conditions is investigated using the new code ABAKO.

  20. The corneal fibrosis response to epithelial-stromal injury.

    Science.gov (United States)

    Torricelli, Andre A M; Santhanam, Abirami; Wu, Jiahui; Singh, Vivek; Wilson, Steven E

    2016-01-01

    The corneal wound healing response, including the development of stromal opacity in some eyes, is a process that often leads to scarring that occurs after injury, surgery or infection to the cornea. Immediately after epithelial and stromal injury, a complex sequence of processes contributes to wound repair and regeneration of normal corneal structure and function. In some corneas, however, often depending on the type and extent of injury, the response may also lead to the development of mature vimentin+ α-smooth muscle actin+ desmin+ myofibroblasts. Myofibroblasts are specialized fibroblastic cells generated in the cornea from keratocyte-derived or bone marrow-derived precursor cells. The disorganized extracellular matrix components secreted by myofibroblasts, in addition to decreased expression of corneal crystallins in these cells, are central biological processes that result in corneal stromal fibrosis associated with opacity or "haze". Several factors are associated with myofibroblast generation and haze development after PRK surgery in rabbits, a reproducible model of scarring, including the amount of tissue ablated, which may relate to the extent of keratocyte apoptosis in the early response to injury, irregularity of stromal surface after surgery, and changes in corneal stromal proteoglycans, but normal regeneration of the epithelial basement membrane (EBM) appears to be a critical factor determining whether a cornea heals with relative transparency or vision-limiting stromal opacity. Structural and functional abnormalities of the regenerated EBM facilitate prolonged entry of epithelium-derived growth factors such as transforming growth factor β (TGF-β) and platelet-derived growth factor (PDGF) into the stroma that both drive development of mature myofibroblasts from precursor cells and lead to persistence of the cells in the anterior stroma. A major discovery that has contributed to our understanding of haze development is that keratocytes and corneal

  1. Bayesian depth estimation from monocular natural images.

    Science.gov (United States)

    Su, Che-Chun; Cormack, Lawrence K; Bovik, Alan C

    2017-05-01

    Estimating an accurate and naturalistic dense depth map from a single monocular photographic image is a difficult problem. Nevertheless, human observers have little difficulty understanding the depth structure implied by photographs. Two-dimensional (2D) images of the real-world environment contain significant statistical information regarding the three-dimensional (3D) structure of the world that the vision system likely exploits to compute perceived depth, monocularly as well as binocularly. Toward understanding how this might be accomplished, we propose a Bayesian model of monocular depth computation that recovers detailed 3D scene structures by extracting reliable, robust, depth-sensitive statistical features from single natural images. These features are derived using well-accepted univariate natural scene statistics (NSS) models and recent bivariate/correlation NSS models that describe the relationships between 2D photographic images and their associated depth maps. This is accomplished by building a dictionary of canonical local depth patterns from which NSS features are extracted as prior information. The dictionary is used to create a multivariate Gaussian mixture (MGM) likelihood model that associates local image features with depth patterns. A simple Bayesian predictor is then used to form spatial depth estimates. The depth results produced by the model, despite its simplicity, correlate well with ground-truth depths measured by a current-generation terrestrial light detection and ranging (LIDAR) scanner. Such a strong form of statistical depth information could be used by the visual system when creating overall estimated depth maps incorporating stereopsis, accommodation, and other conditions. Indeed, even in isolation, the Bayesian predictor delivers depth estimates that are competitive with state-of-the-art "computer vision" methods that utilize highly engineered image features and sophisticated machine learning algorithms.

  2. Human skeleton proportions from monocular data

    Institute of Scientific and Technical Information of China (English)

    PENG En; LI Ling

    2006-01-01

    This paper introduces a novel method for estimating the skeleton proportions ofa human figure from monocular data.The proposed system will first automatically extract the key frames and recover the perspective camera model from the 2D data.The human skeleton proportions are then estimated from the key frames using the recovered camera model without posture reconstruction. The proposed method is tested to be simple, fast and produce satisfactory results for the input data. The human model with estimated proportions can be used in future research involving human body modeling or human motion reconstruction.

  3. The GUI OPAC: Approach with Caution.

    Science.gov (United States)

    Hildreth, Charles R.

    1995-01-01

    Discusses the graphical user interface (GUI) online public access catalog (OPAC), a user interface that uses images to represent options. Topics include user interface design for information retrieval; designing effective bibliographic displays, including subject headings; two design principles; and what GUIs can bring to OPACs. (LRW)

  4. Corneal organ cultures in tyrosinemia release chemotactic factors.

    Science.gov (United States)

    Lohr, K M; Hyndiuk, R A; Hatchell, D L; Kurth, C E

    1985-05-01

    Corneal inflammation with subsequent scarring and blindness occurs in the inherited human metabolic disease tyrosinemia type II, yet putative inflammatory mediators in this disorder and in the avascular cornea in general are poorly defined. In a Tyr-fed rat model of tyrosinemia type II, intracellular crystals, presumably Tyr, are hypothesized to be responsible for the increased lysosomal activity observed in corneal epithelial lesions. Because polymorphonuclear leukocytes (PMNs) are seen only at the site of these lesions, we used this model to study humoral mediators released from Tyr-fed rat corneal organ cultures. Only Tyr-fed rats developed stromal edema and linear granular opacities in gray edematous corneal epithelium, compatible with a noninfectious keratitis. Electron micrographs confirmed epithelial edema and showed focal epithelial necrosis with PMN invasion of the stroma. Only Tyr-fed rat corneal culture supernatants contained chemotactic activity that was heat labile and moderately trypsin sensitive. Four peaks with varying amounts of chemotactic activity were found on Sephadex G-75 chromatography. Although the identity of these peaks of activity has not yet been established, we suggest that they may be responsible for the PMN infiltration observed in this model of corneal inflammation.

  5. Sands of Sahara after LASIK in Avellino Corneal Dystrophy

    Directory of Open Access Journals (Sweden)

    Flavio Mantelli

    2012-01-01

    Full Text Available We report the case of a patient diagnosed with Avellino corneal dystrophy (ACD who developed diffuse interstitial keratitis following excimer laser insitu keratomileusis (LASIK. ACD is an autosomal dominant corneal dystrophy characterized by multiple asymmetric stromal opacities that impair vision. Accepted treatments for this condition include corneal transplantation and phototherapeutic keratectomy (PTK. Our patient underwent LASIK at another institution to correct myopia. LASIK and photorefractive keratectomy (PRK are usually contraindicated in ACD for the high risk of disease recurrence and postoperative complications. The patient came to our attention lamenting blurry vision, decreased visual acuity, and photophobia. Ophthalmologic examination revealed bilateral interstitial keratitis, also known as “sands of Sahara”, a seldom-seen complication of LASIK characterized by fine and diffuse granular infiltrates at the surgical flap interface.The risk of developing interstitial keratitis, as in the case presented here, represents another valid reason for avoiding LASIK in patients with ACD.

  6. TSG-6 protects corneal endothelium from transcorneal cryoinjury in rabbits.

    Science.gov (United States)

    Kim, Jeong-Ah; Ko, Jung Hwa; Ko, Ah Young; Lee, Hyun Ju; Kim, Mee Kum; Wee, Won Ryang; Lee, Ryang Hwa; Fulcher, Samuel F; Oh, Joo Youn

    2014-07-17

    To investigate the effect of an anti-inflammatory protein, TNF-α stimulated gene/protein (TSG)-6 and an antiapoptotic protein, stanniocalcin (STC)-1 on corneal endothelium in rabbits with transcorneal cryoinjury. Transcorneal freezing (-80°C) was applied to rabbit corneas for 30 seconds. Immediately post injury, either TSG-6 (10 μg/100 μL), STC-1 (10 μg/100 μL), or the same volume of balanced salt solution (BSS) was injected into the anterior chamber. Each eye was examined for corneal opacity, corneal thickness, endothelial cell density, and endothelial hexagonality every 2 to 6 hours for 48 hours post injury. The concentrations of myeloperoxidase (MPO) and IL-1β were measured in the aqueous humor every 6 hours. At 48 hours post injury, each cornea was assayed for TNF-α, IL-1β, IL-6, and MPO, and histologically evaluated with alizarin red-trypan blue staining, hematoxylin-eosin staining, and immunostaining for neutrophils. Tumor necrosis factor-α stimulated gene/protein-6 significantly decreased the development of corneal opacity and edema after cryoinjury compared with STC-1 or BSS. The corneal endothelial cell density and hexagonality were markedly preserved by TSG-6. The mRNA levels of TNF-α, IL-1β, and IL-6 in the cornea and the protein levels of MPO and IL-1β in the aqueous humor and cornea were significantly lower in TSG-6-treated eyes than BSS-treated controls. Similarly, the expression of fibroblast growth factor-2 was reduced by TSG-6 treatment. Histologic evaluation demonstrated that neutrophil infiltration of the cornea was decreased in TSG-6-treated eyes. Tumor necrosis factor-α stimulated gene/protein-6 protected corneal endothelial cells from transcorneal cryoinjury through suppression of inflammation. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  7. Tissue engineering of corneal stroma with rabbit fibroblast precursors and gelatin hydrogels.

    Science.gov (United States)

    Mimura, Tatsuya; Amano, Shiro; Yokoo, Seiichi; Uchida, Saiko; Yamagami, Satoru; Usui, Tomohiko; Kimura, Yu; Tabata, Yasuhiko

    2008-01-01

    To isolate fibroblast precursors from rabbit corneal stroma using a sphere-forming assay, to engineer corneal stroma with the precursors and gelatin, and to establish the therapeutic application of precursors in a rabbit corneal stroma. In the in vitro study, a sphere-forming assay was performed to produce precursors from rabbit corneal stroma. Corneal stroma was engineered by cultivating precursors in porous gelatin for one week. In the in vivo study, the engineered corneal stromal sheet with precursors (precursor/gelatin group) or with fibroblasts (fibroblast /gelatin group) or without cells (gelatin group) was transplanted to a pocket of rabbit corneal stroma. Gene expression and extracellular matrix production were examined immunohistochemically in each group one week and four weeks after surgery. In the in vitro study, cells in the spheres were BrdU-positive, and their progeny were keratocan-positive. The study also showed that the corneas transplanted with a porous gelatin sheet did not show any opacity four weeks after transplantation in any group. In the gelatin sheet of the precursor/gelatin group, a more intense expression of type I collagen was observed relative to the other two groups four weeks after the surgery. Our findings demonstrate that the transplantation of fibroblast precursors combined with gelatin hydrogel into the corneal stroma is a possible treatment strategy for corneal stromal regeneration.

  8. Clinical utility of the KAMRA corneal inlay.

    Science.gov (United States)

    Naroo, Shehzad Anjam; Bilkhu, Paramdeep Singh

    2016-01-01

    The treatment of presbyopia has been the focus of much scientific and clinical research over recent years, not least due to an increasingly aging population but also the desire for spectacle independence. Many lens and nonlens-based approaches have been investigated, and with advances in biomaterials and improved surgical methods, removable corneal inlays have been developed. One such development is the KAMRA™ inlay where a small entrance pupil is exploited to create a pinhole-type effect that increases the depth of focus and enables improvement in near visual acuity. Short- and long-term clinical studies have all reported significant improvement in near and intermediate vision compared to preoperative measures following monocular implantation (nondominant eye), with a large proportion of patients achieving Jaeger (J) 2 to J1 (~0.00 logMAR to ~0.10 logMAR) at the final follow-up. Although distance acuity is reduced slightly in the treated eye, binocular visual acuity and function remain very good (mean 0.10 logMAR or better). The safety of the inlay is well established and easily removable, and although some patients have developed corneal changes, these are clinically insignificant and the incidence appears to reduce markedly with advancements in KAMRA design, implantation technique, and femtosecond laser technology. This review aims to summarize the currently published peer-reviewed studies on the safety and efficacy of the KAMRA inlay and discusses the surgical and clinical outcomes with respect to the patient's visual function.

  9. Line broadening and the solar opacity problem

    CERN Document Server

    Krief, M; Gazit, D

    2016-01-01

    The calculation of line widths constitutes a theoretical as well as a computational challenge in the calculation of opacities of hot dense plasmas. Opacity models use line broadening approximations that are untested at stellar interior conditions. Moreover, calculations of atomic spectra nearby the convection zone boundary (CZB) of the sun, indicate a large discrepancy in the K-shell line widths between several atomic codes and the Opacity-Project. In this work, the atomic code STAR is used to study the sensitivity of solar opacities to line-broadening. Atomic spectra of several elements are analyzed and compared within the solar interior. Variations in the solar opacity profile due to changes in the Stark widths are shown to be significant and to result mainly due to K-shell lines. In light of the solar opacity problem, the results are compared with the required opacity variations of the present day sun, as imposed by helioseismic and neutrino observations. It is shown that an increase of the line widths res...

  10. Restricted fish feeding reduces cod otolith opacity

    DEFF Research Database (Denmark)

    Høie, H.; Folkvord, A.; Mosegaard, Henrik

    2008-01-01

    The purpose of this work was to examine the effect of reduced feeding and constant temperature on cod otolith opacity. Three groups of juvenile cod were given restricted food rations at different times for 4 months, resulting in depressed somatic growth. Otolith opacity was measured on pictures...... in otolith opacity were found between individual fish both within groups and between groups. In two of the three groups significantly more translucent otolith material was deposited in response to reduced feeding. Our results show that variations in feeding and hence fish growth resulted in variation...

  11. Corneal mucus plaques.

    Science.gov (United States)

    Fraunfelder, F T; Wright, P; Tripathi, R C

    1977-02-01

    Corneal mucus plaques adhered to the anterior corneal surface in 17 of 67 advanced cases of keratoconjunctivitis sicca. The plaques were translucent to opaque and varied in size and shape, from multiple isolated islands to bizarre patterns involving more than half the corneal surface. Ultrastructurally, they consisted of mucus mixed with desquamated degenerating epithelial cells and proteinaceous and lipoidal material. The condition may be symptomatic but can be controlled and prevented in most cases by topical ocular application of 10% acetylcysteine.

  12. Reversible monocular cataract simulating amaurosis fugax.

    Science.gov (United States)

    Paylor, R R; Selhorst, J B; Weinberg, R S

    1985-07-01

    In a patient having brittle, juvenile-onset diabetes, transient monocular visual loss occurred repeatedly whenever there were wide fluctuations in serum glucose. Amaurosis fugax was suspected. The visual loss differed, however, in that it persisted over a period of hours to several days. Direct observation eventually revealed that the relatively sudden change in vision of one eye was associated with opacification of the lens and was not accompanied by an afferent pupillary defect. Presumably, a hyperosmotic gradient had developed with the accumulation of glucose and sorbitol within the lens. Water was drawn inward, altering the composition of the lens fibers and thereby lowering the refractive index, forming a reversible cataract. Hypoglycemia is also hypothesized to have played a role in the formation of a higher osmotic gradient. The unilaterality of the cataract is attributed to variation in the permeability of asymmetric posterior subcapsular cataracts.

  13. Summary of Fe opacity measurement platform

    Energy Technology Data Exchange (ETDEWEB)

    Nagayama, Taisuke

    2016-05-01

    This powerpoint presentation goes over the Fe opacity measurement platform, including how the experiment works, what can be gathered from the measurements, what can be gathered from the simulations, and the limitations of the experiment.

  14. The neutrino opacity of neutron rich matter

    Energy Technology Data Exchange (ETDEWEB)

    Alcain, P.N., E-mail: pabloalcain@gmail.com [Departamento de Física, FCEyN, UBA and IFIBA, Conicet, Pabellón 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); IFIBA-CONICET (Argentina); Dorso, C.O. [Departamento de Física, FCEyN, UBA and IFIBA, Conicet, Pabellón 1, Ciudad Universitaria, 1428 Buenos Aires (Argentina); IFIBA-CONICET (Argentina)

    2017-05-15

    The study of neutron rich matter, present in neutron star, proto-neutron stars and core-collapse supernovae, can lead to further understanding of the behavior of nuclear matter in highly asymmetric nuclei. Heterogeneous structures are expected to exist in these systems, often referred to as nuclear pasta. We have carried out a systematic study of neutrino opacity for different thermodynamic conditions in order to assess the impact that the structure has on it. We studied the dynamics of the neutrino opacity of the heterogeneous matter at different thermodynamic conditions with semiclassical molecular dynamics model already used to study nuclear multifragmentation. For different densities, proton fractions and temperature, we calculate the very long range opacity and the cluster distribution. The neutrino opacity is of crucial importance for the evolution of the core-collapse supernovae and the neutrino scattering.

  15. New Generation of Los Alamos Opacity Tables

    Science.gov (United States)

    Colgan, James; Kilcrease, D. P.; Magee, N. H.; Sherrill, M. E.; Abdallah, J.; Hakel, P.; Fontes, C. J.; Guzik, J. A.; Mussack, K. A.

    2016-05-01

    We present a new generation of Los Alamos OPLIB opacity tables that have been computed using the ATOMIC code. Our tables have been calculated for all 30 elements from hydrogen through zinc and are publicly available through our website. In this poster we discuss the details of the calculations that underpin the new opacity tables. We also show several recent applications of the use of our opacity tables to solar modeling and other astrophysical applications. In particular, we demonstrate that use of the new opacities improves the agreement between solar models and helioseismology, but does not fully resolve the long-standing `solar abundance' problem. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396.

  16. Antifibrotic effect by activation of peroxisome proliferator-activated receptor-gamma in corneal fibroblasts.

    Science.gov (United States)

    Pan, Hongwei; Chen, Jiansu; Xu, Jintang; Chen, Miaojiao; Ma, Rong

    2009-11-10

    The transformation of quiescent keratocytes to active phenotypes and the ensuing fibrotic response play important roles in corneal scar formation. This study aims to observe the antifibrotic effect of peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist on corneal fibroblasts cultured in vitro, and to explore the potential application of peroxisome proliferator-activated receptor agonist to the prevention of corneal opacity following wound repair. Rabbit corneal keratocytes were cultured in a medium containing 10% serum to induce their transformation to fibroblasts and myofibroblasts, which are similar to those that repair corneas. After incubation with the PPARgamma agonist pioglitazone at different concentrations, the effect of pioglitazone on the migration, contractility, and viability of corneal fibroblasts was examined. The secretion of matrix metalloproteinase-2 and matrix metalloproteinase-9 was determined by gelatin zymography, and the synthesis of collagen I and fibronectin was investigated by western blotting. Treatment with pioglitazone at concentrations ranging from 1 to 10 mum significantly decreased corneal fibroblast migration, as determined by scrape-wound assay, inhibited corneal fibroblast-induced collagen lattice contraction, and reduced MMP-2 and MMP-9 secretion into the supernatant of cell cultures in a dose-dependent manner. The expression of fibronectin was significantly decreased, while the expression of collagen I was only decreased when treated with 10 mum pioglitazone. Cell viability was not evidently changed compared to the control. This in vitro study demonstrated the anti-fibrotic effect of pioglitazone, suggesting that activation of PPARgamma may be a new approach for the treatment of corneal opacity and scar formation in the corneal wound healing process.

  17. Opacity Issues in Games with Imperfect Information

    Directory of Open Access Journals (Sweden)

    Bastien Maubert

    2011-06-01

    Full Text Available We study in depth the class of games with opacity condition, which are two-player games with imperfect information in which one of the players only has imperfect information, and where the winning condition relies on the information he has along the play. Those games are relevant for security aspects of computing systems: a play is opaque whenever the player who has imperfect information never "knows" for sure that the current position is one of the distinguished "secret" positions. We study the problems of deciding the existence of a winning strategy for each player, and we call them the opacity-violate problem and the opacity-guarantee problem. Focusing on the player with perfect information is new in the field of games with imperfect-information because when considering classical winning conditions it amounts to solving the underlying perfect-information game. We establish the EXPTIME-completeness of both above-mentioned problems, showing that our winning condition brings a gap of complexity for the player with perfect information, and we exhibit the relevant opacity-verify problem, which noticeably generalizes approaches considered in the literature for opacity analysis in discrete-event systems. In the case of blindfold games, this problem relates to the two initial ones, yielding the determinacy of blindfold games with opacity condition and the PSPACE-completeness of the three problems.

  18. Observational Constraints on Submillimeter Dust Opacity

    CERN Document Server

    Shirley, Yancy L; Pontoppidan, Klaus M; Wilner, David J; Stutz, Amelia M; Bieging, John H; Evans, Neal J

    2010-01-01

    Infrared extinction maps and submillimeter dust continuum maps are powerful probes of the density structure in the envelope of star-forming cores. We make a direct comparison between infrared and submillimeter dust continuum observations of the low-mass Class 0 core, B335, to constrain the ratio of submillimeter to infrared opacity (\\kaprat) and the submillimeter opacity power-law index ($\\kappa \\propto \\lambda^{-\\beta}$). Using the average value of theoretical dust opacity models at 2.2 \\micron, we constrain the dust opacity at 850 and 450 \\micron . Using new dust continuum models based upon the broken power-law density structure derived from interferometric observations of B335 and the infall model derived from molecular line observations of B335, we find that the opacity ratios are $\\frac{\\kappa_{850}}{\\kappa_{2.2}} = (3.21 - 4.80)^{+0.44}_{-0.30} \\times 10^{-4}$ and $\\frac{\\kappa_{450}}{\\kappa_{2.2}} = (12.8 - 24.8)^{+2.4}_{-1.3} \\times 10^{-4}$ with a submillimeter opacity power-law index of $\\beta_{smm}...

  19. Radiation Transport for Explosive Outflows: Opacity Regrouping

    CERN Document Server

    Wollaeger, Ryan T

    2014-01-01

    Implicit Monte Carlo (IMC) and Discrete Diffusion Monte Carlo (DDMC) are methods used to stochastically solve the radiative transport and diffusion equations, respectively. These methods combine into a hybrid transport-diffusion method we refer to as IMC-DDMC. We explore a multigroup IMC-DDMC scheme that, in DDMC, combines frequency groups with sufficient optical thickness. We term this procedure "opacity regrouping". Opacity regrouping has previously been applied to IMC-DDMC calculations for problems in which the dependence of the opacity on frequency is monotonic. We generalize opacity regrouping to non-contiguous groups and implement this in \\supernu, a code designed to do radiation transport in high-velocity outflows with non-monotonic opacities. We find that regrouping of non-contiguous opacity groups generally improves the speed of IMC-DDMC radiation transport. We present an asymptotic analysis that informs the nature of the Doppler shift in DDMC groups and summarize the derivation of the Gentile-Fleck ...

  20. Analytical opacity formulas for ICF elements

    Energy Technology Data Exchange (ETDEWEB)

    Minguez, E. E-mail: minguez@denim.upm.es; Martel, P.; Gil, J.M.; Rubiano, J.G.; Rodriguez, R

    2002-01-01

    Local Thermodynamic Equilibrium (LTE) opacity codes have been developed by the Instituto de Fusion Nuclear (DENIM) during the last years. JIMENA code (Laser and Particle Beams 6 (1998) 265; Laser and Particle Beams 10 (1992) 651) is an opacity code that solves self-consistently, for each temperature and density, the radial Dirac equation with a local spherically symmetrical potential. Very recently we have developed a new opacity code, called ANALOP, that uses an analytical potential (JQSRT 54 (1995) 621), which can include density and temperature effects for atomic data calculations. Opacities are determined with these two codes for selected elements at different plasma conditions. This work is focused on the determination of Rosseland and Planck mean analytical formulas for several single elements used in ICF targets. A scaling law of these mean opacities is given as a function of the plasma parameters: electron temperature and plasma density. These opacities have been tested with numerical results from other codes and with available experimental results.

  1. RECURRENT CORNEAL EROSION SYNDROME (a review

    Directory of Open Access Journals (Sweden)

    S. V. Trufanov

    2015-01-01

    Full Text Available Recurrent corneal erosion (RCE syndrome is characterized by episodes of recurrent spontaneous epithelial defects. Main clinical symptoms (pain, redness, photophobia, lacrimation occurred at night. Corneal lesions revealed by slit lamp exam vary depending on the presence of corneal epithelium raise, epithelial microcysts or epithelial erosions, stromal infiltrates and opacities. Microtraumas, anterior corneal dystrophies, and herpesvirus give rise to RCE. Other causes or factors which increase the risk of RCE syndrome include meibomian gland dysfunction, keratoconjunctivitis sicca, diabetes, and post-LASIK conditions. Basal membrane abnormalities and instability of epithelial adhesion to stroma play a key role in RCE pathogenesis. Ultrastructural changes in RCE include abnormalities of basal epithelial cells and epithelial basal membrane, absence or deficiency of semi-desmosomes, loss of anchor fibrils. Increase in matrix metalloproteinases and collagenases which contribute to basal membrane destruction results in recurrent erosions and further development of abnormal basal membrane. The goals of RCE therapy are to reduce pain (in acute stage, to stimulate re-epithelization, and to restore «adhesion complex» of basal membrane. In most cases, RCE responds to simple conservative treatment that includes lubricants, healing agents, and eye patches. RCEs that are resistant to simple treatment, require complex approach. Non-invasive methods include long-term contact lens use, instillations of autologous serum (eye drops, injections of botulinum toxin (induces ptosis, antiviral agent use or oral intake of metalloproteinase inhibitors. Cell membrane stabilizers, i.e., antioxidants, should be included into treatment approaches as well. Antioxidant effect of Emoxipine promotes tissue reparation due to the prevention of cell membrane lipid peroxidation as well as due to its anti-hypoxic, angioprotective, and antiplatelet effects. If conservative therapy

  2. A new multiple noncontinuous puncture (pointage technique for corneal tattooing

    Directory of Open Access Journals (Sweden)

    Jin Hyoung Park

    2015-10-01

    Full Text Available AIM:To assess the safety and cosmetic efficacy of a new multiple noncontinuous transepithelial puncture technique for tattooing a decompensated cornea.METHODS:It was anon-comparative clinical case series study.The study examines 33 eyes in 33 patients with total corneal opacity due to corneal decompensation, which developed following intraocular surgery.Corneal tattooing was performed using the multiple noncontinuous transepithelial puncture technique (i.e. pointage. The safety of this new surgical strategy was assessed by occurrence of adverse events for the follow-up period. The cosmetic efficacy was determined by the patient’s cosmetic satisfaction and independent observer’s opinion about patient appearance.RESULTS:Seven women and 26 men were included in the study. The mean age was 46.4±17.5y (range:7-67. In total, 30 of 33 patients (91% reported cosmetic satisfaction within the follow-up period. Only 3 patients (9% required additional tattooing due to cosmetic unsatisfaction. Cosmetic outcomes were analyzed and classified as excellent or good in 13 (39% and 17 (52% patients, respectively. No serious adverse events developed, except delayed epithelial healing in 3 cases.CONCLUSION:The cosmetic outcomes of the multiple noncontinuous transepithelial puncture technique for corneal tattooing were good. The safety of this method is higher than conventional procedures. This new procedure also provides improved cost-effectiveness and safety over current corneal tattooing techniques.

  3. Spontaneous corneal perforation in an eye with Peters' anomaly

    Directory of Open Access Journals (Sweden)

    Kim M

    2013-07-01

    Full Text Available Moosang Kim, Seung-Chan Lee, Seung-Jun Lee Department of Ophthalmology, School of Medicine, Kangwon National University, Chuncheon, South Korea Abstract: A premature female infant underwent her first ophthalmologic examination at the age of 4 weeks. The initial examination of the baby was requested for evaluation of a ‘white spot’ on the surface of her right eye. She had been hospitalized in the neonatal intensive care unit because of systemic abnormalities, such as a right clavicle fracture and microcephaly. Slit-lamp examination of the right eye showed a central corneal opacity, corneal thinning, and an iridocorneal adhesion. The lens and fundus of the right eye could not be observed. We observed no pathologic findings in the left eye. The baby's parents were informed of the high risk for spontaneous corneal perforation without external pressure. At 42 days of age, an ophthalmologic examination of the infant was again requested for evaluation of ‘tears’ from her right eye 3 hours previously. Examination revealed corneal perforation, iris protrusion, and a flat anterior chamber. We performed emergent conjunctival flap surgery. Three months following surgery, the patient's right eye was successfully preserved with no sign of inflammation or leakage. Keywords: conjunctival flap, corneal perforation, Peters' anomaly

  4. Effect of monocular deprivation on rabbit neural retinal cell densities

    Directory of Open Access Journals (Sweden)

    Philip Maseghe Mwachaka

    2015-01-01

    Conclusion: In this rabbit model, monocular deprivation resulted in activity-dependent changes in cell densities of the neural retina in favour of the non-deprived eye along with reduced cell densities in the deprived eye.

  5. Characterization of Corneal Indentation Hysteresis.

    Science.gov (United States)

    Ko, Match W L; Dongming Wei; Leung, Christopher K S

    2015-01-01

    Corneal indentation is adapted for the design and development of a characterization method for corneal hysteresis behavior - Corneal Indentation Hysteresis (CIH). Fourteen porcine eyes were tested using the corneal indentation method. The CIH measured in enucleated porcine eyes showed indentation rate and intraocular pressure (IOP) dependences. The CIH increased with indentation rate at lower IOP ( 25 mmHg). The CIH was linear proportional to the IOP within an individual eye. The CIH was positively correlated with the IOP, corneal in-plane tensile stress and corneal tangent modulus (E). A new method based on corneal indentation for the measurement of Corneal Indentation Hysteresis in vivo is developed. To our knowledge, this is the first study to introduce the corneal indentation hysteresis and correlate the corneal indentation hysteresis and corneal tangent modulus.

  6. Modeling and minimizing interference from corneal birefringence in retinal birefringence scanning for foveal fixation detection.

    Science.gov (United States)

    Irsch, Kristina; Gramatikov, Boris; Wu, Yi-Kai; Guyton, David

    2011-07-01

    Utilizing the measured corneal birefringence from a data set of 150 eyes of 75 human subjects, an algorithm and related computer program, based on Müller-Stokes matrix calculus, were developed in MATLAB for assessing the influence of corneal birefringence on retinal birefringence scanning (RBS) and for converging upon an optical/mechanical design using wave plates ("wave-plate-enhanced RBS") that allows foveal fixation detection essentially independently of corneal birefringence. The RBS computer model, and in particular the optimization algorithm, were verified with experimental human data using an available monocular RBS-based eye fixation monitor. Fixation detection using wave-plate-enhanced RBS is adaptable to less cooperative subjects, including young children at risk for developing amblyopia.

  7. Modeling and minimizing interference from corneal birefringence in retinal birefringence scanning for foveal fixation detection

    Science.gov (United States)

    Irsch, Kristina; Gramatikov, Boris; Wu, Yi-Kai; Guyton, David

    2011-01-01

    Utilizing the measured corneal birefringence from a data set of 150 eyes of 75 human subjects, an algorithm and related computer program, based on Müller-Stokes matrix calculus, were developed in MATLAB for assessing the influence of corneal birefringence on retinal birefringence scanning (RBS) and for converging upon an optical/mechanical design using wave plates (“wave-plate-enhanced RBS”) that allows foveal fixation detection essentially independently of corneal birefringence. The RBS computer model, and in particular the optimization algorithm, were verified with experimental human data using an available monocular RBS-based eye fixation monitor. Fixation detection using wave-plate-enhanced RBS is adaptable to less cooperative subjects, including young children at risk for developing amblyopia. PMID:21750772

  8. Polysaccharide hydrogel combined with mesenchymal stem cells promotes the healing of corneal alkali burn in rats.

    Directory of Open Access Journals (Sweden)

    Yifeng Ke

    Full Text Available Corneal chemical burns are common ophthalmic injuries that may result in permanent visual impairment. Although significant advances have been achieved on the treatment of such cases, the structural and functional restoration of a chemical burn-injured cornea remains challenging. The applications of polysaccharide hydrogel and subconjunctival injection of mesenchymal stem cells (MSCs have been reported to promote the healing of corneal wounds. In this study, polysaccharide was extracted from Hardy Orchid and mesenchymal stem cells (MSCs were derived from Sprague-Dawley rats. Supplementation of the polysaccharide significantly enhanced the migration rate of primarily cultured rat corneal epithelial cells. We examined the therapeutic effects of polysaccharide in conjunction with MSCs application on the healing of corneal alkali burns in rats. Compared with either treatment alone, the combination strategy resulted in significantly better recovery of corneal epithelium and reduction in inflammation, neovascularization and opacity of healed cornea. Polysaccharide and MSCs acted additively to increase the expression of anti-inflammatory cytokine (TGF-β, antiangiogenic cytokine (TSP-1 and decrease those promoting inflammation (TNF-α, chemotaxis (MIP-1α and MCP-1 and angiogenesis (VEGF and MMP-2. This study provided evidence that Hardy Orchid derived polysaccharide and MSCs are safe and effective treatments for corneal alkali burns and that their benefits are additive when used in combination. We concluded that combination therapy with polysaccharide and MSCs is a promising clinical treatment for corneal alkali burns and may be applicable for other types of corneal disorder.

  9. Amodal completion with background determines depth from monocular gap stereopsis.

    Science.gov (United States)

    Grove, Philip M; Ben Sachtler, W L; Gillam, Barbara J

    2006-10-01

    Grove, Gillam, and Ono [Grove, P. M., Gillam, B. J., & Ono, H. (2002). Content and context of monocular regions determine perceived depth in random dot, unpaired background and phantom stereograms. Vision Research, 42, 1859-1870] reported that perceived depth in monocular gap stereograms [Gillam, B. J., Blackburn, S., & Nakayama, K. (1999). Stereopsis based on monocular gaps: Metrical encoding of depth and slant without matching contours. Vision Research, 39, 493-502] was attenuated when the color/texture in the monocular gap did not match the background. It appears that continuation of the gap with the background constitutes an important component of the stimulus conditions that allow a monocular gap in an otherwise binocular surface to be responded to as a depth step. In this report we tested this view using the conventional monocular gap stimulus of two identical grey rectangles separated by a gap in one eye but abutting to form a solid grey rectangle in the other. We compared depth seen at the gap for this stimulus with stimuli that were identical except for two additional small black squares placed at the ends of the gap. If the squares were placed stereoscopically behind the rectangle/gap configuration (appearing on the background) they interfered with the perceived depth at the gap. However when they were placed in front of the configuration this attenuation disappeared. The gap and the background were able under these conditions to complete amodally.

  10. Localization of monocular stimuli in different depth planes.

    Science.gov (United States)

    Shimono, Koichi; Tam, Wa James; Asakura, Nobuhiko; Ohmi, Masao

    2005-09-01

    We examined the phenomenon in which two physically aligned monocular stimuli appear to be non-collinear when each of them is located in binocular regions that are at different depth planes. Using monocular bars embedded in binocular random-dot areas that are at different depths, we manipulated properties of the binocular areas and examined their effect on the perceived direction and depth of the monocular stimuli. Results showed that (1) the relative visual direction and perceived depth of the monocular bars depended on the binocular disparity and the dot density of the binocular areas, and (2) the visual direction, but not the depth, depended on the width of the binocular regions. These results are consistent with the hypothesis that monocular stimuli are treated by the visual system as binocular stimuli that have acquired the properties of their binocular surrounds. Moreover, partial correlation analysis suggests that the visual system utilizes both the disparity information of the binocular areas and the perceived depth of the monocular bars in determining the relative visual direction of the bars.

  11. RADIATION TRANSPORT FOR EXPLOSIVE OUTFLOWS: OPACITY REGROUPING

    Energy Technology Data Exchange (ETDEWEB)

    Wollaeger, Ryan T. [Department of Nuclear Engineering and Engineering Physics, University of Wisconsin, Madison 1500 Engineering Drive, 410 ERB, Madison, WI 53706 (United States); Van Rossum, Daniel R., E-mail: wollaeger@wisc.edu, E-mail: daan@flash.uchicago.edu [Flash Center for Computational Science, Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2014-10-01

    Implicit Monte Carlo (IMC) and Discrete Diffusion Monte Carlo (DDMC) are methods used to stochastically solve the radiative transport and diffusion equations, respectively. These methods combine into a hybrid transport-diffusion method we refer to as IMC-DDMC. We explore a multigroup IMC-DDMC scheme that in DDMC, combines frequency groups with sufficient optical thickness. We term this procedure ''opacity regrouping''. Opacity regrouping has previously been applied to IMC-DDMC calculations for problems in which the dependence of the opacity on frequency is monotonic. We generalize opacity regrouping to non-contiguous groups and implement this in SuperNu, a code designed to do radiation transport in high-velocity outflows with non-monotonic opacities. We find that regrouping of non-contiguous opacity groups generally improves the speed of IMC-DDMC radiation transport. We present an asymptotic analysis that informs the nature of the Doppler shift in DDMC groups and summarize the derivation of the Gentile-Fleck factor for modified IMC-DDMC. We test SuperNu using numerical experiments including a quasi-manufactured analytic solution, a simple 10 group problem, and the W7 problem for Type Ia supernovae. We find that opacity regrouping is necessary to make our IMC-DDMC implementation feasible for the W7 problem and possibly Type Ia supernova simulations in general. We compare the bolometric light curves and spectra produced by the SuperNu and PHOENIX radiation transport codes for the W7 problem. The overall shape of the bolometric light curves are in good agreement, as are the spectra and their evolution with time. However, for the numerical specifications we considered, we find that the peak luminosity of the light curve calculated using SuperNu is ∼10% less than that calculated using PHOENIX.

  12. The opacity of spiral galaxy disks V. Dust opacity, HI distributions and sub-mm emission

    NARCIS (Netherlands)

    Holwerda, BW; Gonzalez, RA; Allen, RJ; van der Kruit, PC

    2005-01-01

    The opacity of spiral galaxy disks, from counts of distant galaxies, is compared to HI column densities. The opacity measurements are calibrated using the "Synthetic Field Method" from Gonzalez et al. (1998, ApJ, 506, 152), Holwerda et al. (2005a, AJ, 129, 1381). When compared for individual disks,

  13. Current status of corneal xenotransplantation.

    Science.gov (United States)

    Kim, Mee Kum; Hara, Hidetaka

    2015-11-01

    Corneal allo-transplantation is a well-established technique to treat corneal blindness. However, the limited availability of human donors demands the exploration of alternative treatments such as corneal xenotransplantation (e.g., pigs as donors) and bioengineered corneas. Since the first attempt of corneal xenotransplantation using a donor pig cornea in 1844, great advances have been made in the development of genetically-engineered pigs, effective immunosuppressive protocols and the establishment of guidelines for the conduction of clinical trials. We highlight immunological and physio-anatomical barriers of corneal xenotransplantation, recent progress of corneal xenotransplantation in non-human-primates studies, and regulatory guidelines to conduct clinical trials for corneal xenotransplantation.

  14. OPserver: opacities and radiative accelerations on demand

    Science.gov (United States)

    Mendoza, C.; González, J.; Seaton, M. J.; Buerger, P.; Bellorín, A.; Meléndez, M.; Rodríguez, L. S.; Delahaye, F.; Zeippen, C. J.; Palacios, E.; Pradhan, A. K.

    2009-05-01

    We report on developments carried out within the Opacity Project (OP) to upgrade atomic database services to comply with e-infrastructure requirements. We give a detailed description of an interactive, online server for astrophysical opacities, referred to as OPserver, to be used in sophisticated stellar modelling where Rosseland mean opacities and radiative accelerations are computed at every depth point and each evolution cycle. This is crucial, for instance, in chemically peculiar stars and in the exploitation of the new asteroseismological data. OPserver, downloadable with the new OPCD_3.0 release from the Centre de Données Astronomiques de Strasbourg, France, computes mean opacities and radiative data for arbitrary chemical mixtures from the OP monochromatic opacities. It is essentially a client-server network restructuring and optimization of the suite of codes included in the earlier OPCD_2.0 release. The server can be installed locally or, alternatively, accessed remotely from the Ohio Supercomputer Center, Columbus, Ohio, USA. The client is an interactive web page or a subroutine library that can be linked to the user code. The suitability of this scheme in grid computing environments is emphasized, and its extension to other atomic database services for astrophysical purposes is discussed.

  15. Corneal blindness and xenotransplantation.

    Science.gov (United States)

    Lamm, Vladimir; Hara, Hidetaka; Mammen, Alex; Dhaliwal, Deepinder; Cooper, David K C

    2014-01-01

    Approximately 39 million people are blind worldwide, with an estimated 285 million visually impaired. The developing world shoulders 90% of the world's blindness, with 80% of causative diseases being preventable or treatable. Blindness has a major detrimental impact on the patient, community, and healthcare spending. Corneal diseases are significant causes of blindness, affecting at least 4 million people worldwide. The prevalence of corneal disease varies between parts of the world. Trachoma, for instance, is the second leading cause of blindness in Africa, after cataracts, but is rarely found today in developed nations. When preventive strategies have failed, corneal transplantation is the most effective treatment for advanced corneal disease. The major surgical techniques for corneal transplantation include penetrating keratoplasty (PK), anterior lamellar keratoplasty, and endothelial keratoplasty (EK). Indications for corneal transplantation vary between countries, with Fuchs' dystrophy being the leading indication in the USA and keratoconus in Australia. With the exception of the USA, where EK will soon overtake PK as the most common surgical procedure, PK is the overwhelming procedure of choice. Success using corneal grafts in developing nations, such as Nepal, demonstrates the feasibility of corneal transplantation on a global scale. The number of suitable corneas from deceased human donors that becomes available will never be sufficient, and so research into various alternatives, for example stem cells, amniotic membrane transplantation, synthetic and biosynthetic corneas, and xenotransplantation, is progressing. While each of these has potential, we suggest that xenotransplantation holds the greatest potential for a corneal replacement. With the increasing availability of genetically engineered pigs, pig corneas may alleviate the global shortage of corneas in the near future.

  16. Richner-Hanhart syndrome (tyrosinemia type II): a case report of delayed diagnosis with pseudodendritic corneal lesion.

    Science.gov (United States)

    Iskeleli, Güzin; Bilgeç, Mustafa Değer; Arici, Ceyhun; Atalay, Eray; Oğreden, Tülin; Aydin, Ahmet

    2011-01-01

    Richner-Hanhart syndrome (tyrosinemia type II) is a rare autosomal recessive disease associated with high serum tyrosine levels caused by the deficiency of tyrosine aminotransferase enzyme. We report a 15-year-old female patient with complaints of bilateral photophobia and tearing, which started during the infancy period. Biomicroscopic examination revealed bilateral circular corneal opacities on the inferior quadrant and small dendritic lesions at the center of the circular opacities. Blood tests showed a tyrosine level of 508 micromol/L (normal range: 30-150). On her dermatologic examination, plantar hyperkeratosis and seborrheic dermatitis were noted, and mild mental retardation was detected. One and a half months after the tyrosine- and phenylalanine-restricted diet, her tyrosine level dropped to 395 micromol/L level, her corneal lesions subsided, and a symptomatic relief was achieved. Tyrosinemia type II should be suspected in patients demonstrating dermatologic signs, especially palmoplantar keratosis, associated with bilateral pseudodendritic corneal lesions unresponsive to antiviral therapy.

  17. Separating monocular and binocular neural mechanisms mediating chromatic contextual interactions.

    Science.gov (United States)

    D'Antona, Anthony D; Christiansen, Jens H; Shevell, Steven K

    2014-04-17

    When seen in isolation, a light that varies in chromaticity over time is perceived to oscillate in color. Perception of that same time-varying light may be altered by a surrounding light that is also temporally varying in chromaticity. The neural mechanisms that mediate these contextual interactions are the focus of this article. Observers viewed a central test stimulus that varied in chromaticity over time within a larger surround that also varied in chromaticity at the same temporal frequency. Center and surround were presented either to the same eye (monocular condition) or to opposite eyes (dichoptic condition) at the same frequency (3.125, 6.25, or 9.375 Hz). Relative phase between center and surround modulation was varied. In both the monocular and dichoptic conditions, the perceived modulation depth of the central light depended on the relative phase of the surround. A simple model implementing a linear combination of center and surround modulation fit the measurements well. At the lowest temporal frequency (3.125 Hz), the surround's influence was virtually identical for monocular and dichoptic conditions, suggesting that at this frequency, the surround's influence is mediated primarily by a binocular neural mechanism. At higher frequencies, the surround's influence was greater for the monocular condition than for the dichoptic condition, and this difference increased with temporal frequency. Our findings show that two separate neural mechanisms mediate chromatic contextual interactions: one binocular and dominant at lower temporal frequencies and the other monocular and dominant at higher frequencies (6-10 Hz).

  18. The effect of contrast on monocular versus binocular reading performance.

    Science.gov (United States)

    Johansson, Jan; Pansell, Tony; Ygge, Jan; Seimyr, Gustaf Öqvist

    2014-05-14

    The binocular advantage in reading performance is typically small. On the other hand research shows binocular reading to be remarkably robust to degraded stimulus properties. We hypothesized that this robustness may stem from an increasing binocular contribution. The main objective was to compare monocular and binocular performance at different stimulus contrasts and assess the level of binocular superiority. A secondary objective was to assess any asymmetry in performance related to ocular dominance. In a balanced repeated measures experiment 18 subjects read texts at three levels of contrast monocularly and binocularly while their eye movements were recorded. The binocular advantage increased with reduced contrast producing a 7% slower monocular reading at 40% contrast, 9% slower at 20% contrast, and 21% slower at 10% contrast. A statistically significant interaction effect was found in fixation duration displaying a more adverse effect in the monocular condition at lowest contrast. No significant effects of ocular dominance were observed. The outcome suggests that binocularity contributes increasingly to reading performance as stimulus contrast decreases. The strongest difference between monocular and binocular performance was due to fixation duration. The findings may pose a clinical point that it may be necessary to consider tests at different contrast levels when estimating reading performance. © 2014 ARVO.

  19. Design of the opacity spectrometer for opacity measurements at the National Ignition Facility

    Science.gov (United States)

    Ross, P. W.; Heeter, R. F.; Ahmed, M. F.; Dodd, E.; Huffman, E. J.; Liedahl, D. A.; King, J. A.; Opachich, Y. P.; Schneider, M. B.; Perry, T. S.

    2016-11-01

    Recent experiments at the Sandia National Laboratory Z facility have called into question models used in calculating opacity, of importance for modeling stellar interiors. An effort is being made to reproduce these results at the National Ignition Facility (NIF). These experiments require a new X-ray opacity spectrometer (OpSpec) spanning 540 eV-2100 eV with a resolving power E/ΔE > 700. The design of the OpSpec is presented. Photometric calculations based on expected opacity data are also presented. First use on NIF is expected in September 2016.

  20. Refractive corneal surgery - discharge

    Science.gov (United States)

    Nearsightedness surgery - discharge; Refractive surgery - discharge; LASIK - discharge; PRK - discharge ... You had refractive corneal surgery to help improve your vision. This surgery uses a laser to reshape your cornea. It corrects mild-to-moderate nearsightedness, ...

  1. Equine corneal surgery and transplantation.

    Science.gov (United States)

    Denis, Heidi M

    2004-08-01

    Corneal disease is common in equine ophthalmology and requires vigilant monitoring and appropriate therapy to optimize the outcome. Many equine corneal diseases, particularly those that progress rapidly, may benefit from surgical intervention. These include descemetoceles, deep corneal lacerations and ulcers, corneal perforation/iris prolapse, ulcerative keratitis, corneal stromal abscesses, and corneoscleral neoplasia. Indications for corneal transplantation include optical, tectonic, therapeutic, and cosmetic purposes. Corneal transplantation is most often implemented in equine patients for tectonic and therapeutic reasons when a cornea is compromised by corneal stromal abscess, iris prolapse, or neoplasia. This article provides an outline of when to consider surgical intervention for corneal disease, the procedures available and expected outcomes, and how appropriate early surgical intervention can dramatically improve the end result.

  2. Central corneal abscess.

    Science.gov (United States)

    van Bijsterveld, O P

    1976-05-01

    Central corneal abscess developed in the experimental animal after inoculation of biologically active staphylococcal strains in a paracentral epithelial lesion of the cornea. These abscesses did not ulcerate, developed only with high inocula, occurred more frequently in immunized rabbits. A serpiginous type of ulceration did not develop at the site of the initial epithelial lesion nor at any other place in the cornea. Histologically, the lesions consisted of densely packed polymorphonuclear leukocytes between the corneal lamellae.

  3. Hazard detection with a monocular bioptic telescope.

    Science.gov (United States)

    Doherty, Amy L; Peli, Eli; Luo, Gang

    2015-09-01

    The safety of bioptic telescopes for driving remains controversial. The ring scotoma, an area to the telescope eye due to the telescope magnification, has been the main cause of concern. This study evaluates whether bioptic users can use the fellow eye to detect in hazards driving videos that fall in the ring scotoma area. Twelve visually impaired bioptic users watched a series of driving hazard perception training videos and responded as soon as they detected a hazard while reading aloud letters presented on the screen. The letters were placed such that when reading them through the telescope the hazard fell in the ring scotoma area. Four conditions were tested: no bioptic and no reading, reading without bioptic, reading with a bioptic that did not occlude the fellow eye (non-occluding bioptic), and reading with a bioptic that partially-occluded the fellow eye. Eight normally sighted subjects performed the same task with the partially occluding bioptic detecting lateral hazards (blocked by the device scotoma) and vertical hazards (outside the scotoma) to further determine the cause-and-effect relationship between hazard detection and the fellow eye. There were significant differences in performance between conditions: 83% of hazards were detected with no reading task, dropping to 67% in the reading task with no bioptic, to 50% while reading with the non-occluding bioptic, and 34% while reading with the partially occluding bioptic. For normally sighted, detection of vertical hazards (53%) was significantly higher than lateral hazards (38%) with the partially occluding bioptic. Detection of driving hazards is impaired by the addition of a secondary reading like task. Detection is further impaired when reading through a monocular telescope. The effect of the partially-occluding bioptic supports the role of the non-occluded fellow eye in compensating for the ring scotoma. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.

  4. Monocular Road Detection Using Structured Random Forest

    Directory of Open Access Journals (Sweden)

    Liang Xiao

    2016-05-01

    Full Text Available Road detection is a key task for autonomous land vehicles. Monocular vision-based road detection algorithms are mostly based on machine learning approaches and are usually cast as classification problems. However, the pixel-wise classifiers are faced with the ambiguity caused by changes in road appearance, illumination and weather. An effective way to reduce the ambiguity is to model the contextual information with structured learning and prediction. Currently, the widely used structured prediction model in road detection is the Markov random field or conditional random field. However, the random field-based methods require additional complex optimization after pixel-wise classification, making them unsuitable for real-time applications. In this paper, we present a structured random forest-based road-detection algorithm which is capable of modelling the contextual information efficiently. By mapping the structured label space to a discrete label space, the test function of each split node can be trained in a similar way to that of the classical random forests. Structured random forests make use of the contextual information of image patches as well as the structural information of the labels to get more consistent results. Besides this benefit, by predicting a batch of pixels in a single classification, the structured random forest-based road detection can be much more efficient than the conventional pixel-wise random forest. Experimental results tested on the KITTI-ROAD dataset and data collected in typical unstructured environments show that structured random forest-based road detection outperforms the classical pixel-wise random forest both in accuracy and efficiency.

  5. Effects of diabetic keratopathy on corneal optical density, central corneal thickness, and corneal endothelial cell counts.

    Science.gov (United States)

    Gao, Feng; Lin, Tao; Pan, Yingzhe

    2016-09-01

    Diabetic keratopathy is an ocular complication that occurs with diabetes. In the present study, the effect of diabetic keratopathy on corneal optical density, central corneal thickness, and corneal endothelial cell count was investigated. One hundred and eighty diabetic patients (360 eyes) were enrolled in the study during the period from March, 2012 to March, 2013. The patients were divided into three age groups: 10 years, with 60 patients per group (120 eyes). During the same period, 60 healthy cases (120 eyes) were selected and labeled as the normal control group. The Pentacam was used to measure the corneal optical density, and central corneal thickness. Specular microscopy was used to examine the corneal endothelial cell density. The coefficient of partial correlation was used to control age and correlate the analysis between the corneal optical density, corneal endothelial cell density, and central corneal thickness. The stage of the disease, the medial and intimal corneal optical density and central corneal thickness was analyzed in the diabetes group. The corneal optical density in the diabetes group increased compared with that of the normal control group. The medial and intimal corneal optical density and central corneal thickness were positively correlated with the course of the disease. However, the corneal endothelial cell density was not associated with the course of diabetes. There was a positive association between the medial and intimal corneal optical density and central corneal thickness of the diabetic patients. In conclusion, the results of the present study show that medial and intimal corneal optical density and central corneal thickness were sensitive indicators for early diabetic keratopathy.

  6. Clinical utility of the KAMRA corneal inlay

    Directory of Open Access Journals (Sweden)

    Naroo SA

    2016-05-01

    Full Text Available Shehzad Anjam Naroo, Paramdeep Singh Bilkhu Ophthalmic Research Group, School of Life & Health Sciences, Aston University, Birmingham, UK Abstract: The treatment of presbyopia has been the focus of much scientific and clinical research over recent years, not least due to an increasingly aging population but also the desire for spectacle independence. Many lens and nonlens-based approaches have been investigated, and with advances in biomaterials and improved surgical methods, removable corneal inlays have been developed. One such development is the KAMRA™ inlay where a small entrance pupil is exploited to create a pinhole-type effect that increases the depth of focus and enables improvement in near visual acuity. Short- and long-term clinical studies have all reported significant improvement in near and intermediate vision compared to preoperative measures following monocular implantation (nondominant eye, with a large proportion of patients achieving Jaeger (J 2 to J1 (~0.00 logMAR to ~0.10 logMAR at the final follow-up. Although distance acuity is reduced slightly in the treated eye, binocular visual acuity and function remain very good (mean 0.10 logMAR or better. The safety of the inlay is well established and easily removable, and although some patients have developed corneal changes, these are clinically insignificant and the incidence appears to reduce markedly with advancements in KAMRA design, implantation technique, and femtosecond laser technology. This review aims to summarize the currently published peer-reviewed studies on the safety and efficacy of the KAMRA inlay and discusses the surgical and clinical outcomes with respect to the patient’s visual function. Keywords: presbyopia, refractive surgery, implants, cornea

  7. Detailed opacity calculations for stellar models

    Science.gov (United States)

    Pain, Jean-Christophe; Gilleron, Franck

    2016-10-01

    We present a state of the art of precise spectral opacity calculations illustrated by stellar applications. The essential role of laboratory experiments to check the quality of the computed data is underlined. We review some X-ray and XUV laser and Z-pinch photo-absorption measurements as well as X-ray emission spectroscopy experiments of hot dense plasmas produced by ultra-high-intensity laser interaction. The measured spectra are systematically compared with the fine-structure opacity code SCO-RCG. Focus is put on iron, due to its crucial role in the understanding of asteroseismic observations of Beta Cephei-type and Slowly Pulsating B stars, as well as in the Sun. For instance, in Beta Cephei-type stars (which should not be confused with Cepheid variables), the iron-group opacity peak excites acoustic modes through the kappa-mechanism. A particular attention is paid to the higher-than-predicted iron opacity measured on Sandia's Z facility at solar interior conditions (boundary of the convective zone). We discuss some theoretical aspects such as orbital relaxation, electron collisional broadening, ionic Stark effect, oscillator-strength sum rules, photo-ionization, or the ``filling-the-gap'' effect of highly excited states.

  8. Ernst Mach and the episode of the monocular depth sensations.

    Science.gov (United States)

    Banks, E C

    2001-01-01

    Although Ernst Mach is widely recognized in psychology for his discovery of the effects of lateral inhibition in the retina ("Mach Bands"), his contributions to the theory of depth perception are not as well known. Mach proposed that steady luminance gradients triggered sensations of depth. He also expanded on Ewald Hering's hypothesis of "monocular depth sensations," arguing that they were subject to the same principle of lateral inhibition as light sensations were. Even after Hermann von Helmholtz's attack on Hering in 1866, Mach continued to develop theories involving the monocular depth sensations, proposing an explanation of perspective drawings in which the mutually inhibiting depth sensations scaled to a mean depth. Mach also contemplated a theory of stereopsis in which monocular depth perception played the primary role. Copyright 2001 John Wiley & Sons, Inc.

  9. Solar opacity calculations using the super-transition-array method

    CERN Document Server

    Krief, M; Gazit, D

    2016-01-01

    An opacity model based on the Super-Transition-Array (STA) method for the calculation of monochromatic opacities of local thermodynamic equilibrium plasmas was developed. The model is described and used to calculate spectral opacities for a solar model implementing the recent AGSS09 composition. Calculations are carried throughout the solar radiative zone. The relative contributions of different chemical elements and photon-matter processes to the total Rosseland mean opacity are analyzed in detail. Monochromatic opacities and charge state distributions were compared with the widely used Opacity-Project (OP) code, for several elements near the radiation-convection interface. STA Rosseland opacities for the solar mixture show a very good agreement with OP and the OPAL opacity code, throughout the radiation zone. Finally, an explicit STA calculation of the full AGSS09 photospheric mixture, including all heavy metals was performed. It was shown that due to their extremely low abundance, and despite being very go...

  10. A Comparison of Monocular and Binocular Depth Perception in 5- and 7-Month-Old Infants.

    Science.gov (United States)

    Granrud, Carl E.; And Others

    1984-01-01

    Compares monocular depth perception with binocular depth perception in five- to seven-month-old infants. Reaching preferences (dependent measure) observed in the monocular condition indicated sensitivity to monocular depth information. Binocular viewing resulted in a far more consistent tendency to reach for the nearer object. (Author)

  11. A corneal mold to restore normal corneal dimensions.

    Science.gov (United States)

    Swinger, C A; Kornmehl, E W; York, S; Forman, J S

    1986-01-01

    A corneal mold is described that provides an MK corneal button of normal thickness and curvature from an edematous, post-mortem button. The uniform, processed tissue can then be used for experimental refractive surgery.

  12. Corneal Topography Analysis of Stromal Corneal Dystrophies

    OpenAIRE

    Kocluk, Yusuf; Yalniz-Akkaya, Zuleyha; Burcu, Ayse; Ornek, Firdevs

    2015-01-01

    Objective: The aim was to compare the corneal topography and tomography parameters of macular corneal dystrophy (MCD), granular corneal dystrophy (GCD) and lattice corneal dystrophy (LCD) patients obtained by Scheimpflug imaging system. Methods: The charts, photographs and topography images of patients were reviewed retrospectively. This study included 73 eyes of 73 patients (28 MCD, 20 GCG and 25 LCD patients). Topography images were obtained by Pentacam (Oculus Optikgerate, Wetzlar, Germany...

  13. The Influence of Monocular Spatial Cues on Vergence Eye Movements in Monocular and Binocular Viewing of 3-D and 2-D Stimuli.

    Science.gov (United States)

    Batvinionak, Anton A; Gracheva, Maria A; Bolshakov, Andrey S; Rozhkova, Galina I

    2015-01-01

    The influence of monocular spatial cues on the vergence eye movements was studied in two series of experiments: (I) the subjects were viewing a 3-D video and also its 2-D version-binocularly and monocularly; and (II) in binocular and monocular viewing conditions, the subjects were presented with stationary 2-D stimuli containing or not containing some monocular indications of spatial arrangement. The results of the series (I) showed that, in binocular viewing conditions, the vergence eye movements were only present in the case of 3-D but not 2-D video, while in the course of monocular viewing of 2-D video, some regular vergence eye movements could be revealed, suggesting that the occluded eye position could be influenced by the spatial organization of the scene reconstructed on the basis of the monocular depth information provided by the viewing eye. The data obtained in series (II), in general, seem to support this hypothesis. © The Author(s) 2015.

  14. [Corneal sensibility following epikeratophakia].

    Science.gov (United States)

    Biermann, H; Grabner, G; Baumgartner, I; Reim, M

    1992-07-01

    The postoperative rate of reinnervation following corneal surgery is widely considered to be a useful indicator of the healing process. This study reports the corneal sensitivity of 14 patients following epikeratophakia for different indications (myopia, aphakia and keratoconus) after time periods ranging from 7 to 104 weeks. All transplants were clear at the time of measurement. A newly developed aesthesiometer (using a low electric current for stimulation) was employed. Nine positions on the operated eye were chosen for the measurements, five locations of the non-operated fellow eye served as controls. On the operated eye the corneal sensitivity peripheral to the trephination were significantly reduced at the 9 and 12 o'clock positions as compared to the other eye. The 3 and 6 o'clock locations showed no significant difference. On the epikeratophakia lenticule the sensitivity was significantly reduced at all points, the center showing the largest difference (p less than 0.001). No correlation with age, sex or the indication for the procedure was observed. Although there was a trend of a positive correlation between the postoperative time period and the central corneal sensitivity, the follow-up was too short to reach significant levels. The nearly complete lack of corneal sensitivity, particularly in the center of the transplant is therefore well compatible with its long-time survival, even when the lenticule has been prepared with the cryolathe and lyophilized for transportation.

  15. Short-Term Monocular Deprivation Enhances Physiological Pupillary Oscillations.

    Science.gov (United States)

    Binda, Paola; Lunghi, Claudia

    2017-01-01

    Short-term monocular deprivation alters visual perception in adult humans, increasing the dominance of the deprived eye, for example, as measured with binocular rivalry. This form of plasticity may depend upon the inhibition/excitation balance in the visual cortex. Recent work suggests that cortical excitability is reliably tracked by dilations and constrictions of the pupils of the eyes. Here, we ask whether monocular deprivation produces a systematic change of pupil behavior, as measured at rest, that is independent of the change of visual perception. During periods of minimal sensory stimulation (in the dark) and task requirements (minimizing body and gaze movements), slow pupil oscillations, "hippus," spontaneously appear. We find that hippus amplitude increases after monocular deprivation, with larger hippus changes in participants showing larger ocular dominance changes (measured by binocular rivalry). This tight correlation suggests that a single latent variable explains both the change of ocular dominance and hippus. We speculate that the neurotransmitter norepinephrine may be implicated in this phenomenon, given its important role in both plasticity and pupil control. On the practical side, our results indicate that measuring the pupil hippus (a simple and short procedure) provides a sensitive index of the change of ocular dominance induced by short-term monocular deprivation, hence a proxy for plasticity.

  16. Parallax error in the monocular head-mounted eye trackers

    DEFF Research Database (Denmark)

    Mardanbeigi, Diako; Witzner Hansen, Dan

    2012-01-01

    This paper investigates the parallax error, which is a common problem of many video-based monocular mobile gaze trackers. The parallax error is defined and described using the epipolar geometry in a stereo camera setup. The main parameters that change the error are introduced and it is shown how...

  17. Monocular SLAM for Autonomous Robots with Enhanced Features Initialization

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2014-04-01

    Full Text Available This work presents a variant approach to the monocular SLAM problem focused in exploiting the advantages of a human-robot interaction (HRI framework. Based upon the delayed inverse-depth feature initialization SLAM (DI-D SLAM, a known monocular technique, several but crucial modifications are introduced taking advantage of data from a secondary monocular sensor, assuming that this second camera is worn by a human. The human explores an unknown environment with the robot, and when their fields of view coincide, the cameras are considered a pseudo-calibrated stereo rig to produce estimations for depth through parallax. These depth estimations are used to solve a related problem with DI-D monocular SLAM, namely, the requirement of a metric scale initialization through known artificial landmarks. The same process is used to improve the performance of the technique when introducing new landmarks into the map. The convenience of the approach taken to the stereo estimation, based on SURF features matching, is discussed. Experimental validation is provided through results from real data with results showing the improvements in terms of more features correctly initialized, with reduced uncertainty, thus reducing scale and orientation drift. Additional discussion in terms of how a real-time implementation could take advantage of this approach is provided.

  18. Monocular 3D display system for presenting correct depth

    Science.gov (United States)

    Sakamoto, Kunio; Hosomi, Takashi

    2009-10-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth.

  19. Monocular SLAM for autonomous robots with enhanced features initialization.

    Science.gov (United States)

    Guerra, Edmundo; Munguia, Rodrigo; Grau, Antoni

    2014-04-02

    This work presents a variant approach to the monocular SLAM problem focused in exploiting the advantages of a human-robot interaction (HRI) framework. Based upon the delayed inverse-depth feature initialization SLAM (DI-D SLAM), a known monocular technique, several but crucial modifications are introduced taking advantage of data from a secondary monocular sensor, assuming that this second camera is worn by a human. The human explores an unknown environment with the robot, and when their fields of view coincide, the cameras are considered a pseudo-calibrated stereo rig to produce estimations for depth through parallax. These depth estimations are used to solve a related problem with DI-D monocular SLAM, namely, the requirement of a metric scale initialization through known artificial landmarks. The same process is used to improve the performance of the technique when introducing new landmarks into the map. The convenience of the approach taken to the stereo estimation, based on SURF features matching, is discussed. Experimental validation is provided through results from real data with results showing the improvements in terms of more features correctly initialized, with reduced uncertainty, thus reducing scale and orientation drift. Additional discussion in terms of how a real-time implementation could take advantage of this approach is provided.

  20. Short-Term Monocular Deprivation Enhances Physiological Pupillary Oscillations

    Directory of Open Access Journals (Sweden)

    Paola Binda

    2017-01-01

    Full Text Available Short-term monocular deprivation alters visual perception in adult humans, increasing the dominance of the deprived eye, for example, as measured with binocular rivalry. This form of plasticity may depend upon the inhibition/excitation balance in the visual cortex. Recent work suggests that cortical excitability is reliably tracked by dilations and constrictions of the pupils of the eyes. Here, we ask whether monocular deprivation produces a systematic change of pupil behavior, as measured at rest, that is independent of the change of visual perception. During periods of minimal sensory stimulation (in the dark and task requirements (minimizing body and gaze movements, slow pupil oscillations, “hippus,” spontaneously appear. We find that hippus amplitude increases after monocular deprivation, with larger hippus changes in participants showing larger ocular dominance changes (measured by binocular rivalry. This tight correlation suggests that a single latent variable explains both the change of ocular dominance and hippus. We speculate that the neurotransmitter norepinephrine may be implicated in this phenomenon, given its important role in both plasticity and pupil control. On the practical side, our results indicate that measuring the pupil hippus (a simple and short procedure provides a sensitive index of the change of ocular dominance induced by short-term monocular deprivation, hence a proxy for plasticity.

  1. Opacity of Shock-Generated Argon Plasmas

    Institute of Scientific and Technical Information of China (English)

    王藩侯; 陈敬平; 周显明; 李西军; 经福谦; 孟续军; 孙永盛

    2001-01-01

    Argon plasmas with uniform density and temperature are generated by a planar shock wave through argon gas. The opacities of argon plasma, covering the thermodynamic states at temperatures of 1.4-2.2eV and in densities of 0.0083- 0.015 g/cm3, are investigated by measuring the emitted radiance versus time at several visible wavelengths. Comparison of the measured opacities with those calculated demonstrates that the average atom model can be used well to describe the essential transport behaviour of photons in argon plasma under the abovementioned thermodynamic condition. A simplified and self-consistent method to deduce the reflectivity R(λ) at the baseplate surface is applied. It demonstrates that the values of R(λ) are all around 0.4 in the experiments, which are basically in agreement with those given by Erskine previously (1994 J. Quant. Spectrosc. Radiat.Transfer 51 97).

  2. Revitalizing the Library OPAC: Interface, Searching, and Display Challenges

    Directory of Open Access Journals (Sweden)

    Jia Mi

    2008-03-01

    Full Text Available The behavior of academic library users has drastically changed in recent years. Internet search engines have become the preferred tool over the library online public access catalog (OPAC for finding information. Libraries are losing ground to online search engines. In this paper, two aspects of OPAC use are studied: (1 the current OPAC interface and searching capabilities, and (2 the OPAC bibliographic display. The purpose of the study is to find answers to the following questions: Why is the current OPAC ineffective? What can libraries and librarians do to deliver an OPAC that is as good as search engines to better serve our users? Revitalizing the library OPAC is one of the pressing issues that has to be accomplished.

  3. Extended Opacity Tables with Higher Temperature-Density-Frequency Resolution

    Science.gov (United States)

    Schillaci, Mark; Orban, Chris; Delahaye, Franck; Pinsonneault, Marc; Nahar, Sultana; Pradhan, Anil

    2015-05-01

    Theoretical models for plasma opacities underpin our understanding of radiation transport in many different astrophysical objects. These opacity models are also relevant to HEDP experiments such as ignition scale experiments on NIF. We present a significantly expanded set of opacity data from the widely utilized Opacity Project, and make these higher resolution data publicly available through OSU's portal with dropbox.com. This expanded data set is used to assess how accurate the interpolation of opacity data in temperature-density-frequency dimensions must be in order to adequately model the properties of most stellar types. These efforts are the beginning of a larger project to improve the theoretical opacity models in light of experimental results at the Sandia Z-pinch showing that the measured opacity of Iron disagrees strongly with all current models.

  4. Hohlraum calculations for the NIF opacity platform

    Science.gov (United States)

    Dodd, E. S.; Perry, T. S.; Tregillis, I. L.; Kline, J. L.; Heeter, R. F.; Liedahl, D. A.; Opachich, Y. P.

    2015-11-01

    A summary of initial hohlraum calculations for planned opacity experiments at the National Ignition Facility (NIF) will be given. The purpose of these experiments is to make LTE opacity measurements of iron at the same conditions as previous experiments on Sandia's Z facility: 156 eV and 190 eV. Ongoing discrepancies between opacity data and theory make corroborating data highly important. The target considered in these calculations is a standard cylindrical hohlraum, with diameter 5.75 mm, but baffles have been placed between the laser hot spot and the sample to maintain the iron in LTE. The hohlraum is driven with a 3 ns flat top laser pulse, but limited to 500 kJ and only the outer beams. The inner beams will be used to drive a capsule implosion, which backlights the iron for the absorption measurements. The iron itself is a thin disk, mixed with magnesium as a spectroscopic tracer, and tamped with beryllium to minimize expansion. A description of the experimental set-up will be given. Supported under the US DOE by the Los Alamos National Security, LLC under contract DE-AC52-06NA25396.

  5. Monocular and binocular edges enhance the perception of stereoscopic slant.

    Science.gov (United States)

    Wardle, Susan G; Palmisano, Stephen; Gillam, Barbara J

    2014-07-01

    Gradients of absolute binocular disparity across a slanted surface are often considered the basis for stereoscopic slant perception. However, perceived stereo slant around a vertical axis is usually slow and significantly under-estimated for isolated surfaces. Perceived slant is enhanced when surrounding surfaces provide a relative disparity gradient or depth step at the edges of the slanted surface, and also in the presence of monocular occlusion regions (sidebands). Here we investigate how different kinds of depth information at surface edges enhance stereo slant about a vertical axis. In Experiment 1, perceived slant decreased with increasing surface width, suggesting that the relative disparity between the left and right edges was used to judge slant. Adding monocular sidebands increased perceived slant for all surface widths. In Experiment 2, observers matched the slant of surfaces that were isolated or had a context of either monocular or binocular sidebands in the frontal plane. Both types of sidebands significantly increased perceived slant, but the effect was greater with binocular sidebands. These results were replicated in a second paradigm in which observers matched the depth of two probe dots positioned in front of slanted surfaces (Experiment 3). A large bias occurred for the surface without sidebands, yet this bias was reduced when monocular sidebands were present, and was nearly eliminated with binocular sidebands. Our results provide evidence for the importance of edges in stereo slant perception, and show that depth from monocular occlusion geometry and binocular disparity may interact to resolve complex 3D scenes. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Galactic cold cores. V. Dust opacity

    Science.gov (United States)

    Juvela, M.; Ristorcelli, I.; Marshall, D. J.; Montillaud, J.; Pelkonen, V.-M.; Ysard, N.; McGehee, P.; Paladini, R.; Pagani, L.; Malinen, J.; Rivera-Ingraham, A.; Lefèvre, C.; Tóth, L. V.; Montier, L. A.; Bernard, J.-P.; Martin, P.

    2015-12-01

    Context. The project Galactic Cold Cores has carried out Herschel photometric observations of interstellar clouds where the Planck satellite survey has located cold and compact clumps. The sources represent different stages of cloud evolution from starless clumps to protostellar cores and are located in different Galactic environments. Aims: We examine this sample of 116 Herschel fields to estimate the submillimetre dust opacity and to search for variations that might be attributed to the evolutionary stage of the sources or to environmental factors, including the location within the Galaxy. Methods: The submillimetre dust opacity was derived from Herschel data, and near-infrared observations of the reddening of background stars are converted into near-infrared optical depth. We investigated the systematic errors affecting these parameters and used modelling to correct for the expected biases. The ratio of 250 μm and J band opacities is correlated with the Galactic location and the star formation activity. We searched for local variations in the ratio τ(250 μm)/τ(J) using the correlation plots and opacity ratio maps. Results: We find a median ratio of τ(250 μm) /τ(J) = (1.6 ± 0.2) × 10-3, which is more than three times the mean value reported for the diffuse medium. Assuming an opacity spectral index β = 1.8 instead of β = 2.0, the value would be lower by ~ 30%. No significant systematic variation is detected with Galactocentric distance or with Galactic height. Examination of the τ(250 μm) /τ(J) maps reveals six fields with clear indications of a local increase of submillimetre opacity of up to τ(250 μm) /τ(J) ~ 4 × 10-3 towards the densest clumps. These are all nearby fields with spatially resolved clumps of high column density. Conclusions: We interpret the increase in the far-infrared opacity as a sign of grain growth in the densest and coldest regions of interstellar clouds. Planck (http://www.esa.int/Planck) is a project of the European

  7. Anatomic Predictive Factors of Acute Corneal Hydrops in Keratoconus: An Optical Coherence Tomography Study.

    Science.gov (United States)

    Fuentes, Esteban; Sandali, Otman; El Sanharawi, Mohamed; Basli, Elena; Hamiche, Taous; Goemaere, Isabelle; Borderie, Vincent; Bouheraoua, Nacim; Laroche, Laurent

    2015-08-01

    To define the optical coherence tomography (OCT) corneal changes predisposing to acute corneal hydrops among patients with advanced keratoconus. Retrospective cohort study. A total of 191 advanced keratoconic eyes from 191 patients with advanced keratoconus cases were studied. Data collected from patients with advanced keratoconus cases were studied during a minimum period of 24 months of follow-up. High-resolution Fourier-domain corneal OCT (5 μm of axial resolution) and corneal topography were performed every 4 months during the follow-up. Several anatomic features at the keratoconus cone were analyzed with OCT, including epithelial and stromal thicknesses, the aspect of Bowman's layer, the presence of Vogt's striae, and stromal opacities. A comparative analysis between anatomic corneal features in eyes that developed corneal hydrops and those that did not develop this complication during the follow-up was performed. Evaluation of anatomic corneal changes at risk of developing a corneal hydrops on the basis of OCT findings. Eleven cases of corneal hydrops (5.8%) occurred in our series during a mean follow-up of 30 months (24-36 months). All of these patients were male and younger (23.7±5.9 years) than patients with no acute keratoconus (32.7±11.3 years). Increased epithelial thickening with stromal thinning at the conus and the presence of anterior hyperreflectives at the Bowman's layer level were significantly associated with corneal hydrops, whereas the presence of corneal scarring was a preventive factor. At the healing stage, a pan-stromal scar occurs, with a significant stromal thickening and cornea flattening. Increased epithelial thickening, stromal thinning at the keratoconus cone, anterior hyperreflectives at the Bowman's layer level, and the absence of stromal scarring are associated with a high risk of developing corneal hydrops. These aspects should be taken into account by the clinician in the evaluation of keratoconus eyes and in the planning of

  8. Mean gas opacity for circumstellar environments and equilibrium temperature degeneracy

    CERN Document Server

    Malygin, M G; Klahr, H; Dullemond, C P; Henning, Th

    2014-01-01

    In a molecular cloud dust opacity typically dominates over gas opacity, yet in the vicinities of forming stars dust is depleted, and gas is the sole provider of opacity. In the optically thin circumstellar environments the radiation temperature cannot be assumed to be equal to the gas temperature, hence the two-temperature Planck means are necessary to calculate the radiative equilibrium. By using the two-temperature mean opacity one does obtain the proper equilibrium gas temperature in a circumstellar environment, which is in a chemical equilibrium. A careful consideration of a radiative transfer problem reveals that the equilibrium temperature solution can be degenerate in an optically thin gaseous environment. We compute mean gas opacities based on the publicly available code DFSYNTHE by Kurucz and Castelli. We performed the calculations assuming local thermodynamic equilibrium and an ideal gas equation of state. The values were derived by direct integration of the high-resolution opacity spectrum. We prod...

  9. IPOPv2 online service for the generation of opacity tables

    Science.gov (United States)

    Delahaye, Franck; Zwölf, Carlo Maria; Zeippen, Claude J.; Mendoza, Claudio

    2016-03-01

    In the framework of the present phase - IPOPv2 - of the international Opacity Project (OP), a new web service has been implemented based on the latest release of the OP opacities. The user may construct online opacity tables to be conveniently included in stellar evolution codes in the format most commonly adopted by stellar physicists, namely the OPAL format. This facility encourages the use and comparison of both the OPAL and OP data sets in applications. The present service allows for the calculation of multi-element mixtures containing the 17 species (H, He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Cr, Mn, Fe and Ni) considered by the OP, and underpins the latest release of OP opacities. This new service provides tables of Rosseland mean opacites using OP atomic data. We provide an alternative to the OPAL opacity services allowing direct comparison as well as study of the effect of uncertainties in stellar modeling due to mean opacities.

  10. IPOPv2 online service for the generation of opacity tables

    CERN Document Server

    Delahaye, F; Zeippen, C; Mendoza, C

    2015-01-01

    In the framework of the present phase -- IPOPv2 -- of the international Opacity Project (OP), a new web service has been implemented based on the latest release of the OP opacities. The user may construct online opacity tables to be conveniently included in stellar evolution codes in the format most commonly adopted by stellar physicists, namely the OPAL format. This facility encourages the use and comparison of both the OPAL and OP data sets in applications. The present service allows for the calculation of multi-element mixtures containing the 17 species (H, He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Cr, Mn, Fe and Ni) considered by the OP, and underpins the latest release of OP opacities. This new service provides tables of Rosseland mean opacites using OP atomic data. We provide an alternative to the OPAL opacity services allowing direct comparison as well as study of the effect of uncertainties in stellar modeling due to mean opacities.

  11. Disseminated neurocysticercosis presenting as isolated acute monocular painless vision loss

    Directory of Open Access Journals (Sweden)

    Gaurav M Kasundra

    2014-01-01

    Full Text Available Neurocysticercosis, the most common parasitic infection of the nervous system, is known to affect the brain, eyes, muscular tissues and subcutaneous tissues. However, it is very rare for patients with ocular cysts to have concomitant cerebral cysts. Also, the dominant clinical manifestation of patients with cerebral cysts is either seizures or headache. We report a patient who presented with acute monocular painless vision loss due to intraocular submacular cysticercosis, who on investigation had multiple cerebral parenchymal cysticercal cysts, but never had any seizures. Although such a vision loss after initiation of antiparasitic treatment has been mentioned previously, acute monocular vision loss as the presenting feature of ocular cysticercosis is rare. We present a brief review of literature along with this case report.

  12. fMRI investigation of monocular pattern rivalry.

    Science.gov (United States)

    Mendola, Janine D; Buckthought, Athena

    2013-01-01

    In monocular pattern rivalry, a composite image is shown to both eyes. The patient experiences perceptual alternations in which the two stimulus components alternate in clarity or salience. We used fMRI at 3T to image brain activity while participants perceived monocular rivalry passively or indicated their percepts with a task. The stimulus patterns were left/right oblique gratings, face/house composites, or a nonrivalrous control stimulus that did not support the perception of transparency or image segmentation. All stimuli were matched for luminance, contrast, and color. Compared with the control stimulus, the cortical activation for passive viewing of grating rivalry included dorsal and ventral extrastriate cortex, superior and inferior parietal regions, and multiple sites in frontal cortex. When the BOLD signal for the object rivalry task was compared with the grating rivalry task, a similar whole-brain network was engaged, but with significantly greater activity in extrastriate regions, including V3, V3A, fusiform face area (FFA), and parahippocampal place area (PPA). In addition, for the object rivalry task, FFA activity was significantly greater during face-dominant periods whereas parahippocampal place area activity was greater during house-dominant periods. Our results demonstrate that slight stimulus changes that trigger monocular rivalry recruit a large whole-brain network, as previously identified for other forms of bistability. Moreover, the results indicate that rivalry for complex object stimuli preferentially engages extrastriate cortex. We also establish that even with natural viewing conditions, endogenous attentional fluctuations in monocular pattern rivalry will differentially drive object-category-specific cortex, similar to binocular rivalry, but without complete suppression of the nondominant image.

  13. The effect of induced monocular blur on measures of stereoacuity.

    Science.gov (United States)

    Odell, Naomi V; Hatt, Sarah R; Leske, David A; Adams, Wendy E; Holmes, Jonathan M

    2009-04-01

    To determine the effect of induced monocular blur on stereoacuity measured with real depth and random dot tests. Monocular visual acuity deficits (range, 20/15 to 20/1600) were induced with 7 different Bangerter filters (depth tests and Preschool Randot (PSR) and Distance Randot (DR) random dot tests. Stereoacuity results were grouped as either "fine" (60 and 200 arcsec to nil) stereo. Across visual acuity deficits, stereoacuity was more severely degraded with random dot (PSR, DR) than with real depth (Frisby, FD2) tests. Degradation to worse-than-fine stereoacuity consistently occurred at 0.7 logMAR (20/100) or worse for Frisby, 0.1 logMAR (20/25) or worse for PSR, and 0.1 logMAR (20/25) or worse for FD2. There was no meaningful threshold for the DR because worse-than-fine stereoacuity was associated with -0.1 logMAR (20/15). Course/nil stereoacuity was consistently associated with 1.2 logMAR (20/320) or worse for Frisby, 0.8 logMAR (20/125) or worse for PSR, 1.1 logMAR (20/250) or worse for FD2, and 0.5 logMAR (20/63) or worse for DR. Stereoacuity thresholds are more easily degraded by reduced monocular visual acuity with the use of random dot tests (PSR and DR) than real depth tests (Frisby and FD2). We have defined levels of monocular visual acuity degradation associated with fine and nil stereoacuity. These findings have important implications for testing stereoacuity in clinical populations.

  14. A smart telerobotic system driven by monocular vision

    Science.gov (United States)

    Defigueiredo, R. J. P.; Maccato, A.; Wlczek, P.; Denney, B.; Scheerer, J.

    1994-01-01

    A robotic system that accepts autonomously generated motion and control commands is described. The system provides images from the monocular vision of a camera mounted on a robot's end effector, eliminating the need for traditional guidance targets that must be predetermined and specifically identified. The telerobotic vision system presents different views of the targeted object relative to the camera, based on a single camera image and knowledge of the target's solid geometry.

  15. Building a 3D scanner system based on monocular vision.

    Science.gov (United States)

    Zhang, Zhiyi; Yuan, Lin

    2012-04-10

    This paper proposes a three-dimensional scanner system, which is built by using an ingenious geometric construction method based on monocular vision. The system is simple, low cost, and easy to use, and the measurement results are very precise. To build it, one web camera, one handheld linear laser, and one background calibration board are required. The experimental results show that the system is robust and effective, and the scanning precision can be satisfied for normal users.

  16. Monocular nasal hemianopia from atypical sphenoid wing meningioma.

    Science.gov (United States)

    Stacy, Rebecca C; Jakobiec, Frederick A; Lessell, Simmons; Cestari, Dean M

    2010-06-01

    Neurogenic monocular nasal field defects respecting the vertical midline are quite uncommon. We report a case of a unilateral nasal hemianopia that was caused by compression of the left optic nerve by a sphenoid wing meningioma. Histological examination revealed that the pathology of the meningioma was consistent with that of an atypical meningioma, which carries a guarded prognosis with increased chance of recurrence. The tumor was debulked surgically, and the patient's visual field defect improved.

  17. Indoor monocular mobile robot navigation based on color landmarks

    Institute of Scientific and Technical Information of China (English)

    LUO Yuan; ZHANG Bai-sheng; ZHANG Yi; LI Ling

    2009-01-01

    A robot landmark navigation system based on monocular camera was researched theoretically and experimentally. First the landmark setting and its data structure in programming was given; then the coordinates of them getting by robot and global localization of the robot was described; finally experiments based on Pioneer III mobile robot show that this system can work well at different topographic situation without lose of signposts.

  18. Altered anterior visual system development following early monocular enucleation

    Directory of Open Access Journals (Sweden)

    Krista R. Kelly

    2014-01-01

    Conclusions: The novel finding of an asymmetry in morphology of the anterior visual system following long-term survival from early monocular enucleation indicates altered postnatal visual development. Possible mechanisms behind this altered development include recruitment of deafferented cells by crossing nasal fibres and/or geniculate cell retention via feedback from primary visual cortex. These data highlight the importance of balanced binocular input during postnatal maturation for typical anterior visual system morphology.

  19. Solar Opacity Calculations Using the Super-transition-array Method

    Science.gov (United States)

    Krief, M.; Feigel, A.; Gazit, D.

    2016-04-01

    A new opacity model has been developed based on the Super-Transition-Array (STA) method for the calculation of monochromatic opacities of plasmas in local thermodynamic equilibrium. The atomic code, named STAR (STA-Revised), is described and used to calculate spectral opacities for a solar model implementing the recent AGSS09 composition. Calculations are carried out throughout the solar radiative zone. The relative contributions of different chemical elements and atomic processes to the total Rosseland mean opacity are analyzed in detail. Monochromatic opacities and charge-state distributions are compared with the widely used Opacity Project (OP) code, for several elements near the radiation-convection interface. STAR Rosseland opacities for the solar mixture show a very good agreement with OP and the OPAL opacity code throughout the radiation zone. Finally, an explicit STA calculation was performed of the full AGSS09 photospheric mixture, including all heavy metals. It was shown that, due to their extremely low abundance, and despite being very good photon absorbers, the heavy elements do not affect the Rosseland opacity.

  20. SOLAR OPACITY CALCULATIONS USING THE SUPER-TRANSITION-ARRAY METHOD

    Energy Technology Data Exchange (ETDEWEB)

    Krief, M.; Feigel, A.; Gazit, D., E-mail: menahem.krief@mail.huji.ac.il [The Racah Institute of Physics, The Hebrew University, 91904 Jerusalem (Israel)

    2016-04-10

    A new opacity model has been developed based on the Super-Transition-Array (STA) method for the calculation of monochromatic opacities of plasmas in local thermodynamic equilibrium. The atomic code, named STAR (STA-Revised), is described and used to calculate spectral opacities for a solar model implementing the recent AGSS09 composition. Calculations are carried out throughout the solar radiative zone. The relative contributions of different chemical elements and atomic processes to the total Rosseland mean opacity are analyzed in detail. Monochromatic opacities and charge-state distributions are compared with the widely used Opacity Project (OP) code, for several elements near the radiation–convection interface. STAR Rosseland opacities for the solar mixture show a very good agreement with OP and the OPAL opacity code throughout the radiation zone. Finally, an explicit STA calculation was performed of the full AGSS09 photospheric mixture, including all heavy metals. It was shown that, due to their extremely low abundance, and despite being very good photon absorbers, the heavy elements do not affect the Rosseland opacity.

  1. Corneal Neurotoxicity Due to Topical Benzalkonium Chloride

    OpenAIRE

    Sarkar, Joy; Chaudhary, Shweta; Namavari, Abed; Ozturk, Okan; Chang, Jin-Hong; Yco, Lisette; Sonawane, Snehal; Khanolkar, Vishakha; Hallak, Joelle; Jain, Sandeep

    2012-01-01

    Topical application of benzalkonium chloride (BAK) to the eye causes dose-related corneal neurotoxicity. Corneal inflammation and reduction in aqueous tear production accompany neurotoxicity. Cessation of BAK treatment leads to recovery of corneal nerve density.

  2. A Highest Order Hypothesis Compatibility Test for Monocular SLAM

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2013-08-01

    Full Text Available Simultaneous Location and Mapping (SLAM is a key problem to solve in order to build truly autonomous mobile robots. SLAM with a unique camera, or monocular SLAM, is probably one of the most complex SLAM variants, based entirely on a bearing-only sensor working over six DOF. The monocular SLAM method developed in this work is based on the Delayed Inverse-Depth (DI-D Feature Initialization, with the contribution of a new data association batch validation technique, the Highest Order Hypothesis Compatibility Test, HOHCT. The Delayed Inverse-Depth technique is used to initialize new features in the system and defines a single hypothesis for the initial depth of features with the use of a stochastic technique of triangulation. The introduced HOHCT method is based on the evaluation of statistically compatible hypotheses and a search algorithm designed to exploit the strengths of the Delayed Inverse- Depth technique to achieve good performance results. This work presents the HOHCT with a detailed formulation of the monocular DI-D SLAM problem. The performance of the proposed HOHCT is validated with experimental results, in both indoor and outdoor environments, while its costs are compared with other popular approaches.

  3. A Highest Order Hypothesis Compatibility Test for Monocular SLAM

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2013-08-01

    Full Text Available Simultaneous Location and Mapping (SLAM is a key problem to solve in order to build truly autonomous mobile robots. SLAM with a unique camera, or monocular SLAM, is probably one of the most complex SLAM variants, based entirely on a bearing-only sensor working over six DOF. The monocular SLAM method developed in this work is based on the Delayed Inverse-Depth (DI-D Feature Initialization, with the contribution of a new data association batch validation technique, the Highest Order Hypothesis Compatibility Test, HOHCT. The Delayed Inverse-Depth technique is used to initialize new features in the system and defines a single hypothesis for the initial depth of features with the use of a stochastic technique of triangulation. The introduced HOHCT method is based on the evaluation of statistically compatible hypotheses and a search algorithm designed to exploit the strengths of the Delayed Inverse-Depth technique to achieve good performance results. This work presents the HOHCT with a detailed formulation of the monocular DI-D SLAM problem. The performance of the proposed HOHCT is validated with experimental results, in both indoor and outdoor environments, while its costs are compared with other popular approaches.

  4. High Accuracy Monocular SFM and Scale Correction for Autonomous Driving.

    Science.gov (United States)

    Song, Shiyu; Chandraker, Manmohan; Guest, Clark C

    2016-04-01

    We present a real-time monocular visual odometry system that achieves high accuracy in real-world autonomous driving applications. First, we demonstrate robust monocular SFM that exploits multithreading to handle driving scenes with large motions and rapidly changing imagery. To correct for scale drift, we use known height of the camera from the ground plane. Our second contribution is a novel data-driven mechanism for cue combination that allows highly accurate ground plane estimation by adapting observation covariances of multiple cues, such as sparse feature matching and dense inter-frame stereo, based on their relative confidences inferred from visual data on a per-frame basis. Finally, we demonstrate extensive benchmark performance and comparisons on the challenging KITTI dataset, achieving accuracy comparable to stereo and exceeding prior monocular systems. Our SFM system is optimized to output pose within 50 ms in the worst case, while average case operation is over 30 fps. Our framework also significantly boosts the accuracy of applications like object localization that rely on the ground plane.

  5. Genetics of corneal endothelial dystrophies

    Indian Academy of Sciences (India)

    Chitra Kannabiran

    2009-12-01

    The corneal endothelium maintains the level of hydration in the cornea. Dysfunction of the endothelium results in excess accumulation of water in the corneal stroma, leading to swelling of the stroma and loss of transparency. There are four different corneal endothelial dystrophies that are hereditary, progressive, non-inflammatory disorders involving dysfunction of the corneal endothelium. Each of the endothelial dystrophies is genetically heterogeneous with different modes of transmission and/or different genes involved in each subtype. Genes responsible for disease have been identified for only a subset of corneal endothelial dystrophies. Knowledge of genes involved and their function in the corneal endothelium can aid understanding the pathogenesis of the disorder as well as reveal pathways that are important for normal functioning of the endothelium.

  6. First solar models with OPAS opacity tables

    CERN Document Server

    Pennec, Maëlle Le; Salmon, Sébastien; Blancard, Christophe; Cossé, Philippe; Faussurier, Gérald; Mondet, Guillaume

    2015-01-01

    Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However the particular case of Sun is still challenging. The helioseismic sound speed determination continues to disagree with the Standard Solar Model (SSM) prediction for about a decade, questioning the reliability of this model. One of the sources of uncertainty could be in the treatment of the transport of radiation from the solar core to the surface. In this letter, we use the new OPAS opacity tables, recently available for solar modelling, to address this issue. We discuss first the peculiarities of these tables, then we quantify their impact on the solar sound speed and density profiles using the reduced OPAS tables taken on the grids of the OPAL ones. We use the two evolution codes MESA and CLES that led to similar conclusions in the solar radiative zone. In comparison to commonly used OPAL opacity tables, the new solar models computed, for the most recent photosphe...

  7. Bilateral acute corneal calcification.

    Science.gov (United States)

    Freddo, T F; Leibowitz, H M

    1985-04-01

    A 38-year-old man with brittle, juvenile onset diabetes mellitus and bilateral severe dry eyes with recurrent corneal ulcers developed atypical band-shaped calcifications of both corneas during a 24-hour period. Serum calcium, phosphate, and carbon dioxide levels all were within normal limits. The patient was mildly uremic but was not in renal failure. When EDTA chelation failed to clear the deposits, partial keratectomies were performed in both eyes and the specimens were examined by light and electron microscopy, including energy dispersive x-ray analysis. Microscopic studies revealed an atypical calcific keratopathy which involved neither Bowman's layer nor the most superficial stromal lamellae. The deposits were confined to deeper lamellae in the anterior stroma and by electron microscopy were composed of extracellular crystalline aggregates. Energy dispersive x-ray analysis of these aggregates confirmed the presence of calcium and phosphate. Corneal dessication appeared to be a major contributing factor in the rapid formation of these deposits.

  8. Comparison of FDA safety and efficacy data for KAMRA and Raindrop corneal inlays

    Directory of Open Access Journals (Sweden)

    Majid Moshirfar

    2017-09-01

    Full Text Available AIM: To provide a side-by-side analysis of the summary of safety and effectiveness data (SSED submitted to the FDA for the KAMRA and Raindrop corneal inlays for the correction of presbyopia. METHODS: SSED reports submitted to the FDA for KAMRA and Raindrop were compared with respect to loss of corrected distance visual acuity (CDVA, adverse event rates, induction of astigmatism, retention of contrast sensitivity, stability of manifest refractive spherical equivalent (MRSE, and achieved monocular uncorrected near visual acuity (UNVA at 24mo. RESULTS: Totally 442/508 of KAMRA patients and 344/373 Raindrop patients remained enrolled in the clinical trials at 24mo. The proportion of KAMRA and Raindrop patients who lost ≥2 lines of CDVA at 24mo was 3.4% and 1%, respectively. The adverse event rate was comparable between the devices. No significant inductions of astigmatism were noted. Both technologies induced a transient myopic shift in MRSE followed by a hyperopic shift and subsequent stabilization. Totally 87% of KAMRA and 98% of Raindrop patients attained a monocular UNVA of J5 (20/40 or better at 24mo, 28% of KAMRA and 67% of Raindrop patients attained a monocular UNVA of J1 (20/20 or better at 24mo. CONCLUSION: Both devices can be considered safe and effective, however, the results of corneal inlay implantation are mixed, and long-term patient satisfaction will likely depend on subjective expectations about the capabilities of the inlays. Variability in surgical technique and postoperative care within and between the two clinical trials diminishes the comparative power of this article.

  9. Corneal blindness: prevention, treatment and rehabilitation

    Directory of Open Access Journals (Sweden)

    Matthew J Burton

    2009-12-01

    Full Text Available Blindness from corneal disease is a major ophthalmic public health problem. There are three important elements to addressing corneal blindness: prevention, treatment, and rehabilitation.

  10. Ketamine/Xylazine-Induced Corneal Damage in Mice.

    Directory of Open Access Journals (Sweden)

    Demelza Koehn

    Full Text Available We have observed that the commonly used ketamine/xylazine anesthesia mix can induce a focally severe and permanent corneal opacity. The purpose of this study was to establish the clinical and histological features of this deleterious side effect, its sensitivity with respect to age and anesthesia protocol, and approaches for avoiding it.Young C57BL/6J, C57BLKS/J, and SJL/J mice were treated with permutations of anesthesia protocols and compared using slit-lamp exams, optical coherence tomography, histologic analyses, and telemetric measurements of body temperature.Ketamine/xylazine induces corneal damage in mice with a variable frequency. Among 12 experimental cohorts, corneal damage associated with ketamine/xylazine was observed in 9 of them. Despite various treatments to avoid corneal dehydration during anesthesia, the frequency of corneas experiencing damage among responding cohorts was 42% (26% inclusive of all cohorts, which is significantly greater than the natural prevalence (5%. The damage was consistent with band keratopathy. It appeared as a white or gray horizontal band located proximal to the pupil and was positive for subepithelial calcium deposition with von Kossa stain.The sum of our clinical and histological observations is consistent with ketamine/xylazine-induced band keratopathy in mice. This finding is relevant for mouse studies involving the eye and/or vision-dependent behavioral assays, which would both be prone to artifact without appreciation of the damage caused by ketamine/xylazine anesthesia. Use of yohimbine is suggested as a practical means of avoiding this complication.

  11. [Therapy for systemic metabolic disorders based on the detection of basic corneal landmarks in childhood].

    Science.gov (United States)

    Lisch, W; Pitz, S; Geerling, G

    2013-06-01

    Many systemic lysosomal storage disorders show basic corneal opacities already in childhood. The lysosome is a cell organelle, produced by Golgi's apparatus, that is surrounded by a membrane and contains hydrolytic enzymes that break down food molecules, especially proteins and other complex molecules. The ophthalmologist's precise diagnosis of corneal clouding at the slit-lamp may reveal the correct interpretation of the specific lysosomal storage disorder. It is very important to diagnose such diseases as soon as possible because today the development of systemic enzymatic therapies has broadened the therapeutic armamentarium for the current standard of care. The following corneal landmarks of systemic storage diseases and of the modern systemic therapy are presented: cornea verticillata in Fabry's disease, periodic infusion of alpha-galactosidase a; Kayser-Fleischer's ring in Wilson's disease, zinc, trienetin, low copper diet; multiple, punctiform crystals in cystinosis, cysteamine, Raptor RP 103(DR cysteamine) that reduces the cytotoxity in form of continous dissolving of cystine from lysosome, renal transplantation, haematopoietic stem cell transplantation; peripheral ring, but not true lipid arc, and moderate stromal haze in LCAT-deficiency, injection of recombinant enzyme or of encapsulated LCAT-secreting cells; diffuse stromal haze in mucopolysaccharidoses (MPS). Enzyme replacement therapy is currently indicated for MPS I, MPS II, and MPS VI, haematopoietic stem cell transplantation; painful, bilateral pseudo-dendritic opacities in tyrosinemia type II (eponym: Richner-Hanhart syndrome), low phenylalanine and tyrosine diet result in complete disappearance of corneal alterations with a consecutive painfree period. Strict diet during the whole life is necessary to prevent corneal recurrences and the occurrence of palmo-plantar keratoses. Such therapies can enable the patient to lead an otherwise normal life for decades.

  12. Calculation of Free-Free Opacities

    Science.gov (United States)

    Bhatia, A. K.; Maiden, D.; Ritchie, A. B., Jr.

    2003-01-01

    Free-free absorption is an important contribution to the opacity for radiation transport through hot materials Temperatures can be as high as several keV, such that it becomes a computational challenge to solve the Schrodinger equation efficiently for rapidly oscillating continuum functions for high angular momenta. Several groups\\footnots, including ours, have studied the phase amplitude solution (PAS) of the Schrodinger equation, in which one solves equations for the wave function amplitude and phase, which are: smooth functions of the electron energy. It is also important to have an accurate Schroudinger benchmark for the development of the PAS method. We present results for dipole matrix elements, Gaunt factors, and cross sections for the absorption of radiation at various energies for Cs XIX at temperature=100 eV and density=0.187 g/cc for our newly developed PAS and Schrodinger benchmark.

  13. Surgery for Pulmonary Multiple Ground Glass Opacities

    Directory of Open Access Journals (Sweden)

    Qun WANG

    2016-06-01

    Full Text Available The incidence of pulmonary ground glass opacity (GGO has been increasing in recent years, with a great number of patients having multiple GGOs. Unfortunately, the management of multiple GGOs is still controversial. Pulmonary GGO is a radiological term, consisting of different pathological types. Some of the GGOs are early-staged lung cancer. GGO is an indolent nodule, only a small proportion of GGOs change during observation, which does not influence the efficacy of surgery. . The timing of surgery for multiple GGOs mainly depends on the predominant nodule and surgery is recommended if the solid component of the predominant nodule >5 mm. Either lobectomy or sub-lobectomy is feasible. GGOs other than the predominant nodule can be left unresected. Multiple GGOs with high risk factors need mediastinal lymph node dissection or sampling.

  14. An opacity-sampled treatment of water vapor

    Science.gov (United States)

    Alexander, David R.; Augason, Gordon C.; Johnson, Hollis R.

    1989-01-01

    Although the bands of H2O are strong in the spectra of cool stars and calculations have repeatedly demonstrated their significance as opacity sources, only approximate opacities are currently available, due both to the difficulty of accounting for the millions of lines involved and to the inadequacy of laboratory and theoretical data. To overcome these obstacles, a new treatment is presented, based upon a statistical representation of the water vapor spectrum derived from available laboratory data. This statistical spectrum of water vapor employs an exponential distribution of line strengths and random positions of lines whose overall properties are forced to reproduce the mean opacities observed in the laboratory. The resultant data set is then treated by the opacity-sampling method exactly as are all other lines, both molecular and atomic. Significant differences are found between the results of this improved treatment and the results obtained with previous treatments of water-vapor opacity.

  15. A New Generation of Los Alamos Opacity Tables

    CERN Document Server

    Colgan, J; Magee, N H; Sherrill, M E; Abdallah,, J; Hakel, P; Fontes, C J; Guzik, J A; Mussack, K A

    2016-01-01

    We present a new, publicly available, set of Los Alamos OPLIB opacity tables for the elements hydrogen through zinc. Our tables are computed using the Los Alamos ATOMIC opacity and plasma modeling code, and make use of atomic structure calculations that use fine-structure detail for all the elements considered. Our equation-of-state (EOS) model, known as ChemEOS, is based on the minimization of free energy in a chemical picture and appears to be a reasonable and robust approach to determining atomic state populations over a wide range of temperatures and densities. In this paper we discuss in detail the calculations that we have performed for the 30 elements considered, and present some comparisons of our monochromatic opacities with measurements and other opacity codes. We also use our new opacity tables in solar modeling calculations and compare and contrast such modeling with previous work.

  16. Decrease in monocular sleep after sleep deprivation in the domestic chicken

    NARCIS (Netherlands)

    Boerema, AS; Riedstra, B; Strijkstra, AM

    2003-01-01

    We investigated the trade-off between sleep need and alertness, by challenging chickens to modify their monocular sleep. We sleep deprived domestic chickens (Gallus domesticus) to increase their sleep need. We found that in response to sleep deprivation the fraction of monocular sleep within sleep

  17. Decrease in monocular sleep after sleep deprivation in the domestic chicken

    NARCIS (Netherlands)

    Boerema, AS; Riedstra, B; Strijkstra, AM

    2003-01-01

    We investigated the trade-off between sleep need and alertness, by challenging chickens to modify their monocular sleep. We sleep deprived domestic chickens (Gallus domesticus) to increase their sleep need. We found that in response to sleep deprivation the fraction of monocular sleep within sleep d

  18. Deformable Surface 3D Reconstruction from Monocular Images

    CERN Document Server

    Salzmann, Matthieu

    2010-01-01

    Being able to recover the shape of 3D deformable surfaces from a single video stream would make it possible to field reconstruction systems that run on widely available hardware without requiring specialized devices. However, because many different 3D shapes can have virtually the same projection, such monocular shape recovery is inherently ambiguous. In this survey, we will review the two main classes of techniques that have proved most effective so far: The template-based methods that rely on establishing correspondences with a reference image in which the shape is already known, and non-rig

  19. Automatic gear sorting system based on monocular vision

    Directory of Open Access Journals (Sweden)

    Wenqi Wu

    2015-11-01

    Full Text Available An automatic gear sorting system based on monocular vision is proposed in this paper. A CCD camera fixed on the top of the sorting system is used to obtain the images of the gears on the conveyor belt. The gears׳ features including number of holes, number of teeth and color are extracted, which is used to categorize the gears. Photoelectric sensors are used to locate the gears׳ position and produce the trigger signals for pneumatic cylinders. The automatic gear sorting is achieved by using pneumatic actuators to push different gears into their corresponding storage boxes. The experimental results verify the validity and reliability of the proposed method and system.

  20. Corneal Densitometry for Quantification of Corneal Deposits in Monoclonal Gammopathies.

    Science.gov (United States)

    Enders, Philip; Holtick, Udo; Schaub, Friederike; Tuchscherer, Armin; Hermann, Manuel M; Scheid, Christoph; Cursiefen, Claus; Bachmann, Björn O

    2017-04-01

    To assess the capability of Scheimpflug-based densitometry of the cornea to quantify light chain deposits in patients with active monoclonal gammopathies. This is a case-control study in which data from a leading tertiary university center in myeloma care were analyzed. Ten eyes of 5 patients with monoclonal gammopathy and 26 eyes of 13 healthy controls undergoing clinical evaluation and Scheimpflug-based measurements were included in the study. The main outcome measures were densitometry data of the 4 corneal layers-anterior layer (AL), central layer (CL), posterior layer, and total layer (TL)-in 4 different annuli (central annular zone 0-2 mm, intermediate annular zone 2-6 mm, peripheral annular zone 6-10 mm, and total annular zone 0-12 mm). In 8 eyes of 4 patients with IgG-based gammopathy, corneal light backscatter was highest in the AL and decreased with increasing corneal depth. The peripheral annular zone showed a higher densitometry value compared with the corneal center. Compared with healthy controls, the AL (P < 0.001), the CL (P < 0.001), and the TL (P < 0.001) had significantly higher corneal light backscatter in patients with gammopathy in the total and the peripheral annular zones. In one patient with predominantly IgA-based disease, corneal light backscatter was not elevated. Scheimpflug-based densitometry of the cornea is able to quantify opacification by immunoglobulin G light chain deposits in monoclonal gammopathies. This noninvasive technique can complement presently used in vivo confocal microscopy and corneal photography to objectivize corneal changes. Densitometry might allow monitoring of corneal immunoglobulin deposits in follow-up examinations.

  1. Monocular occlusions determine the perceived shape and depth of occluding surfaces.

    Science.gov (United States)

    Tsirlin, Inna; Wilcox, Laurie M; Allison, Robert S

    2010-06-01

    Recent experiments have established that monocular areas arising due to occlusion of one object by another contribute to stereoscopic depth perception. It has been suggested that the primary role of monocular occlusions is to define depth discontinuities and object boundaries in depth. Here we use a carefully designed stimulus to demonstrate empirically that monocular occlusions play an important role in localizing depth edges and defining the shape of the occluding surfaces in depth. We show that the depth perceived via occlusion in our stimuli is not due to the presence of binocular disparity at the boundary and discuss the quantitative nature of depth perception in our stimuli. Our data suggest that the visual system can use monocular information to estimate not only the sign of the depth of the occluding surface but also its magnitude. We also provide preliminary evidence that perceived depth of illusory occluders derived from monocular information can be biased by binocular features.

  2. Monocular accommodation condition in 3D display types through geometrical optics

    Science.gov (United States)

    Kim, Sung-Kyu; Kim, Dong-Wook; Park, Min-Chul; Son, Jung-Young

    2007-09-01

    Eye fatigue or strain phenomenon in 3D display environment is a significant problem for 3D display commercialization. The 3D display systems like eyeglasses type stereoscopic or auto-stereoscopic multiview, Super Multi-View (SMV), and Multi-Focus (MF) displays are considered for detail calculation about satisfaction level of monocular accommodation by geometrical optics calculation means. A lens with fixed focal length is used for experimental verification about numerical calculation of monocular defocus effect caused by accommodation at three different depths. And the simulation and experiment results consistently show relatively high level satisfaction about monocular accommodation at MF display condition. Additionally, possibility of monocular depth perception, 3D effect, at monocular MF display is discussed.

  3. Rosseland and Flux Mean Opacities for Compton Scattering

    Science.gov (United States)

    Poutanen, Juri

    2017-02-01

    Rosseland mean opacity plays an important role in theories of stellar evolution and X-ray burst models. In the high-temperature regime, when most of the gas is completely ionized, the opacity is dominated by Compton scattering. Our aim here is to critically evaluate previous works on this subject and to compute the exact Rosseland mean opacity for Compton scattering over a broad range of temperature and electron degeneracy parameter. We use relativistic kinetic equations for Compton scattering and compute the photon mean free path as a function of photon energy by solving the corresponding integral equation in the diffusion limit. As a byproduct we also demonstrate the way to compute photon redistribution functions in the case of degenerate electrons. We then compute the Rosseland mean opacity as a function of temperature and electron degeneracy and present useful approximate expressions. We compare our results to previous calculations and find a significant difference in the low-temperature regime and strong degeneracy. We then proceed to compute the flux mean opacity in both free-streaming and diffusion approximations, and show that the latter is nearly identical to the Rosseland mean opacity. We also provide a simple way to account for the true absorption in evaluating the Rosseland and flux mean opacities.

  4. Replicating the Z iron opacity experiments on the NIF

    Science.gov (United States)

    Perry, T. S.; Heeter, R. F.; Opachich, Y. P.; Ross, P. W.; Kline, J. L.; Flippo, K. A.; Sherrill, M. E.; Dodd, E. S.; DeVolder, B. G.; Cardenas, T.; Archuleta, T. N.; Craxton, R. S.; Zhang, R.; McKenty, P. W.; Garcia, E. M.; Huffman, E. J.; King, J. A.; Ahmed, M. F.; Emig, J. A.; Ayers, S. L.; Barrios, M. A.; May, M. J.; Schneider, M. B.; Liedahl, D. A.; Wilson, B. G.; Urbatsch, T. J.; Iglesias, C. A.; Bailey, J. E.; Rochau, G. A.

    2017-06-01

    X-ray opacity is a crucial factor of all radiation-hydrodynamics calculations, yet it is one of the least validated of the material properties in the simulation codes. Recent opacity experiments at the Sandia Z-machine have shown up to factors of two discrepancies between theory and experiment, casting doubt on the validity of the opacity models. Therefore, a new experimental opacity platform is being developed on the National Ignition Facility (NIF) not only to verify the Z-machine experimental results but also to extend the experiments to other temperatures and densities. The first experiments will be directed towards measuring the opacity of iron at a temperature of ∼160 eV and an electron density of ∼7 × 1021 cm-3. Preliminary experiments on NIF have demonstrated the ability to create a sufficiently bright point backlighter using an imploding plastic capsule and also a hohlraum that can heat the opacity sample to the desired conditions. The first of these iron opacity experiments is expected to be performed in 2017.

  5. Linear opacities on HRCT in bronchiolitis obliterans organising pneumonia

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, J.M.; Flower, C.D.R. [Dept. of Radiology, Addenbrookes Hospital, Univ. of Cambridge (United Kingdom); Schnyder, P.; Leuenberger, P. [Depts. of Radiology and Medicine, University Hospital, CHUV, Lausanne (Switzerland); Verschakelen, J. [Dept. of Radiology, University Hospital, Leuven (Belgium)

    1999-07-01

    The aim of this study was to report the high-resolution computed tomography (HRCT) appearances of linear opacities that may occur in isolation or in combination with other changes in bronchiolitis obliterans organising pneumonia (BOOP). Eleven patients with BOOP and linear opacities on HRCT were identified at three independent teaching hospitals. The HRCT images and clinical course of each patient were reviewed. Two distinct types of linear opacity were identified. The type-1 opacity extended in a radial manner along the line of the bronchi towards the pleura and was usually intimately related to bronchi. The type-2 opacity occurred in a sub-pleural location and bore no relationship to the bronchi. Both types occurred most commonly in the lower lobes, frequently were associated with multi-focal areas of consolidation and usually completely resolved with treatment. There was no associated bronchiectasis, irreversible volume loss or a reticular or honeycomb pattern. In 2 patients linear opacities were the sole abnormality on HRCT. Bronchiolitis obliterans organising pneumonia may occur in a pure ''linear form'' or HRCT may demonstrate linear opacities in addition to multi-focal consolidation. (orig.)

  6. Computing NLTE Opacities -- Node Level Parallel Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Holladay, Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-11

    Presentation. The goal: to produce a robust library capable of computing reasonably accurate opacities inline with the assumption of LTE relaxed (non-LTE). Near term: demonstrate acceleration of non-LTE opacity computation. Far term (if funded): connect to application codes with in-line capability and compute opacities. Study science problems. Use efficient algorithms that expose many levels of parallelism and utilize good memory access patterns for use on advanced architectures. Portability to multiple types of hardware including multicore processors, manycore processors such as KNL, GPUs, etc. Easily coupled to radiation hydrodynamics and thermal radiative transfer codes.

  7. Calculation and Analysis of Mean Opacity of Gold Mixtures

    Institute of Scientific and Technical Information of China (English)

    YAN An-ying; JIANG Ming; CHENG Xin-lu; YANG Xiang-dong

    2007-01-01

    A screened hydrogenic model for l splitting (SHML) is used to calculate the Rosseland mean opacities of high-Z Au, Ta, Yb, Ho, Gd, Sm, Nd, Sn, Ag plasmas and mixtures of gold and these elements at high temperature (T=200-400eV) and dense (ρ=1g/cm3).From the calculated Rosseland mean opacities of the mixtures, Au-Nd seems to be a better choice than other mixtures.Simultaneously, the reason that the mean opacities of mixture of Au-Sn decrease slightly when T=400eV is analyzed.

  8. Opacity Calculations for Non-Local Thermodynamic Equilibrium Mixtures

    Institute of Scientific and Technical Information of China (English)

    吴泽清; 韩国兴; 逄锦桥

    2002-01-01

    Based on the average atom model, a non-local thermodynamic equilibrium (non-LTE) model is developed to calculate opacity for mixtures. This model could be applied to high-Z problems. The mean ionization degrees of SiO2 of the present calculation are slightly higher compared with another model for mixtures. As an example, the opacity of Au and Nd mixture is calculated. The results show concrete non-LTE effects and the increase in opacity of the mixture is shown clearly.

  9. Monocular camera and IMU integration for indoor position estimation.

    Science.gov (United States)

    Zhang, Yinlong; Tan, Jindong; Zeng, Ziming; Liang, Wei; Xia, Ye

    2014-01-01

    This paper presents a monocular camera (MC) and inertial measurement unit (IMU) integrated approach for indoor position estimation. Unlike the traditional estimation methods, we fix the monocular camera downward to the floor and collect successive frames where textures are orderly distributed and feature points robustly detected, rather than using forward oriented camera in sampling unknown and disordered scenes with pre-determined frame rate and auto-focus metric scale. Meanwhile, camera adopts the constant metric scale and adaptive frame rate determined by IMU data. Furthermore, the corresponding distinctive image feature point matching approaches are employed for visual localizing, i.e., optical flow for fast motion mode; Canny Edge Detector & Harris Feature Point Detector & Sift Descriptor for slow motion mode. For superfast motion and abrupt rotation where images from camera are blurred and unusable, the Extended Kalman Filter is exploited to estimate IMU outputs and to derive the corresponding trajectory. Experimental results validate that our proposed method is effective and accurate in indoor positioning. Since our system is computationally efficient and in compact size, it's well suited for visually impaired people indoor navigation and wheelchaired people indoor localization.

  10. Surface formation and depth in monocular scene perception.

    Science.gov (United States)

    Albert, M K

    1999-01-01

    The visual perception of monocular stimuli perceived as 3-D objects has received considerable attention from researchers in human and machine vision. However, most previous research has focused on how individual 3-D objects are perceived. Here this is extended to a study of how the structure of 3-D scenes containing multiple, possibly disconnected objects and features is perceived. Da Vinci stereopsis, stereo capture, and other surface formation and interpolation phenomena in stereopsis and structure-from-motion suggest that small features having ambiguous depth may be assigned depth by interpolation with features having unambiguous depth. I investigated whether vision may use similar mechanisms to assign relative depth to multiple objects and features in sparse monocular images, such as line drawings, especially when other depth cues are absent. I propose that vision tends to organize disconnected objects and features into common surfaces to construct 3-D-scene interpretations. Interpolations that are too weak to generate a visible surface percept may still be strong enough to assign relative depth to objects within a scene. When there exists more than one possible surface interpolation in a scene, the visual system's preference for one interpolation over another seems to be influenced by a number of factors, including: (i) proximity, (ii) smoothness, (iii) a preference for roughly frontoparallel surfaces and 'ground' surfaces, (iv) attention and fixation, and (v) higher-level factors. I present a variety of demonstrations and an experiment to support this surface-formation hypothesis.

  11. A Novel Metric Online Monocular SLAM Approach for Indoor Applications

    Directory of Open Access Journals (Sweden)

    Yongfei Li

    2016-01-01

    Full Text Available Monocular SLAM has attracted more attention recently due to its flexibility and being economic. In this paper, a novel metric online direct monocular SLAM approach is proposed, which can obtain the metric reconstruction of the scene. In the proposed approach, a chessboard is utilized to provide initial depth map and scale correction information during the SLAM process. The involved chessboard provides the absolute scale of scene, and it is seen as a bridge between the camera visual coordinate and the world coordinate. The scene is reconstructed as a series of key frames with their poses and correlative semidense depth maps, using a highly accurate pose estimation achieved by direct grid point-based alignment. The estimated pose is coupled with depth map estimation calculated by filtering over a large number of pixelwise small-baseline stereo comparisons. In addition, this paper formulates the scale-drift model among key frames and the calibration chessboard is used to correct the accumulated pose error. At the end of this paper, several indoor experiments are conducted. The results suggest that the proposed approach is able to achieve higher reconstruction accuracy when compared with the traditional LSD-SLAM approach. And the approach can also run in real time on a commonly used computer.

  12. Human Pose Estimation from Monocular Images: A Comprehensive Survey

    Directory of Open Access Journals (Sweden)

    Wenjuan Gong

    2016-11-01

    Full Text Available Human pose estimation refers to the estimation of the location of body parts and how they are connected in an image. Human pose estimation from monocular images has wide applications (e.g., image indexing. Several surveys on human pose estimation can be found in the literature, but they focus on a certain category; for example, model-based approaches or human motion analysis, etc. As far as we know, an overall review of this problem domain has yet to be provided. Furthermore, recent advancements based on deep learning have brought novel algorithms for this problem. In this paper, a comprehensive survey of human pose estimation from monocular images is carried out including milestone works and recent advancements. Based on one standard pipeline for the solution of computer vision problems, this survey splits the problem into several modules: feature extraction and description, human body models, and modeling methods. Problem modeling methods are approached based on two means of categorization in this survey. One way to categorize includes top-down and bottom-up methods, and another way includes generative and discriminative methods. Considering the fact that one direct application of human pose estimation is to provide initialization for automatic video surveillance, there are additional sections for motion-related methods in all modules: motion features, motion models, and motion-based methods. Finally, the paper also collects 26 publicly available data sets for validation and provides error measurement methods that are frequently used.

  13. Post intrastromal corneal ring segments insertion complicated by Candida parapsilosis keratitis

    Science.gov (United States)

    Mitchell, Bradley M; Kanellopoulos, A John; Font, Ramon L

    2013-01-01

    This case report describes the clinical and histopathologic features, including molecular confirmation, of fungal keratitis after intrastromal corneal ring segments placement for keratoconus. A 52-year-old woman underwent insertion of Intacs® corneal implants for treatment of keratoconus. Extrusion of the implants was noted 5 months post insertion and replaced. Three months later, monocular infiltrates and an epithelial defect were observed. The Intacs were removed and the infiltrates were treated with ofloxacin and prednisolone acetate. Microbial cultures and stains were negative. The patient demonstrated flares and exacerbation one month later. Mycoplasma and/or fungus were suspected and treated without improvement. Therapeutic keratoplasty was performed 10 months following initial placement of the corneal ring implants. The keratectomy specimen was analyzed by light microscopy and a panfungal polymerase chain reaction assay. A histopathologic diagnosis of Candida parapsilosis keratitis was made and confirmed by polymerase chain reaction. One year postoperatively, a systemic workup of the patient was done with no signs of recurrence. This rare report of fungal keratitis following Intacs insertion is the first reported case of C. parapsilosis complicating Intacs implantation. PMID:23467516

  14. Post intrastromal corneal ring segments insertion complicated by Candida parapsilosis keratitis

    Directory of Open Access Journals (Sweden)

    Mitchell BM

    2013-02-01

    Full Text Available Bradley M Mitchell,1 A John Kanellopoulos,2 Ramon L Font31Eclipse IS Consulting, Rosenberg, TX, 2Department of Ophthalmology, New York University Medical School, New York City, NY, 3Department of Ophthalmology, Ophthalmic Pathology Laboratory, Cullen Eye Institute, Baylor College of Medicine, Houston, TX, USAAbstract: This case report describes the clinical and histopathologic features, including molecular confirmation, of fungal keratitis after intrastromal corneal ring segments placement for keratoconus. A 52-year-old woman underwent insertion of Intacs® corneal implants for treatment of keratoconus. Extrusion of the implants was noted 5 months post insertion and replaced. Three months later, monocular infiltrates and an epithelial defect were observed. The Intacs were removed and the infiltrates were treated with ofloxacin and prednisolone acetate. Microbial cultures and stains were negative. The patient demonstrated flares and exacerbation one month later. Mycoplasma and/or fungus were suspected and treated without improvement. Therapeutic keratoplasty was performed 10 months following initial placement of the corneal ring implants. The keratectomy specimen was analyzed by light microscopy and a panfungal polymerase chain reaction assay. A histopathologic diagnosis of Candida parapsilosis keratitis was made and confirmed by polymerase chain reaction. One year postoperatively, a systemic workup of the patient was done with no signs of recurrence. This rare report of fungal keratitis following Intacs insertion is the first reported case of C. parapsilosis complicating Intacs implantation.Keywords: keratoconus, Intacs®, polymerase chain reaction, PCR, molecular diagnosis, histopathology

  15. In vivo confocal microscopy of an apparent deep stroma corneal dystrophy: a case report

    Science.gov (United States)

    2009-01-01

    A 41-year-old white woman was referred to our Department to rule out the presence of a Fuch's corneal dystrophy. On slit-lamp biomicroscopy, small bilateral punctuate opacities appearing mostly in the posterior stroma were observed, suggesting a differential diagnosis of pre-Descemet's dystrophy as opposed to Cornea Farinata. Confocal microscopy in the central cornea of both eyes revealed the normal appearance of superficial and basal epithelial layers. However throughout the full thickness of the cornea fine highly refractive granules, localized both in the keratocytes cytoplasm and in the stroma matrix were noted. In both eyes abnormal polymegatism and pleomorphism was observed. PMID:20062640

  16. Endoscopy-guided vitreoretinal surgery following penetrating corneal injury: a case report

    Directory of Open Access Journals (Sweden)

    Motoko Kawashima

    2010-08-01

    Full Text Available Motoko Kawashima1, Shinichi Kawashima2, Murat Dogru1,3, Makoto Inoue4, Jun Shimazaki1,51Department of Ophthalmology, Tokyo Dental College, Chiba, Japan; 2Department of Ophthalmology, International University of Health and Welfare, Tokyo, Japan; 3Department of Ocular Surface and Visual Optics, Keio University School of Medicine, Tokyo, Japan; 4Kyorin Eye Center, Tokyo, Japan; 5Department of Ophthalmology, Keio University School of Medicine, Tokyo, JapanIntroduction: Severe ocular trauma requires emergency surgery, and a fresh corneal graft may not always be available. We describe a case of perforating eye injury with corneal ­opacity, suspected endophthalmitis, and an intraocular foreign body. The patient was successfully treated with a two-step procedure comprising endoscopy-guided vitrectomy followed by corneal transplantation. This surgical technique offers a good option to vitrectomy with simultaneous keratoplasty in emergency cases where no graft is immediately available and there is the ­possibility of infection due to the presence of a foreign body.Case presentation: A 55-year-old Japanese woman was referred to our hospital with a ­perforating corneal and lens injury sustained with a muddy ferrous rod. Primary corneal sutures and lensectomy were performed immediately. Vitreoretinal surgery was required due to ­suspected endophthalmitis, vitreous hemorrhage, retinal detachment, dialysis and necrosis of the peripheral retina. Instead of conventional vitrectomy, endoscopy-guided vitreous surgery was performed with the Solid Fiber Catheter AS-611 (FiberTech, Tokyo, Japan due to the presence of corneal opacity and the unavailability of a donor cornea. The retina was successfully attached with the aid of a silicon oil tamponade. Following removal of the silicon oil at 3 months after surgery, penetrating keratoplasty and intraocular lens implantation with ciliary sulcus suture fixation were performed. At 6 months after penetrating

  17. Rosseland and flux mean opacities for Compton scattering

    CERN Document Server

    Poutanen, Juri

    2016-01-01

    Rosseland mean opacity plays an important role in theories of stellar evolution and X-ray burst models. In the high-temperature regime, when most of the gas is completely ionized, the opacity is dominated by Compton scattering. Our aim here is to critically evaluate previous works on this subject and to compute exact Rosseland mean opacity for Compton scattering in a broad range of temperatures and electron degeneracy parameter. We use relativistic kinetic equations for Compton scattering and compute the photon mean free path as a function of photon energy by solving the corresponding integral equation in the diffusion limit. As a byproduct we also demonstrate the way to compute photon redistribution functions in case of degenerate electrons. We then compute the Rosseland mean opacity as a function of temperature and electron degeneracy. We compare our results to the previous calculations and find a significant difference in the low-temperature regime and strong degeneracy. We find useful analytical expressio...

  18. Is Seeing Believing? Consumer Responses to Opacity of Product Packaging

    National Research Council Canada - National Science Library

    Sucharita Chandran; Rishtee Kumar Batra; Benjamin Lawrence

    2009-01-01

      Prior studies have shown that product and packaging design influences consumer reactions and purchase behaviors, however, research has neglected to examine a package's opacity or lack of transparency...

  19. Opacity Experiments At The National Ignition Facility (NIF)

    Science.gov (United States)

    Perry, T. S.; Kline, J. L.; Flippo, K. A.; Sherrill, M. E.; Dodd, E. S.; Devolder, B. G.; Urbatsch, T. J.; Heeter, R. F.; Schneider, M. B.; Liedahl, D. A.; Wilson, B. G.; Iglesias, C. A.; Opachich, Y. P.; Ross, P. W.; Bailey, J. E.; Rochau, G. A.

    2016-10-01

    X-ray opacities are essential to the radiation-hydrodynamic simulations used to model astrophysical systems or inertial confinement fusion experiments. Recent opacity experiments have shown up to a factor of two discrepancy between theory and experiment. To address this issue a new experimental opacity platform is being developed on the NIF to crosscheck the recent results. The first experiments, starting in 2017, will begin by measuring the opacity of iron at a temperature of 160 eV and an electron density of 7x1021 cm-3. This and several following presentations will describe this effort. This work was performed under the auspices of the U.S. Department of Energy by Los Alamos National Lab under Contract DE-AC52-06NA25396.

  20. [The effect of Solcoseryl eye gel in combination with neomycin and bacitracin on the healing of corneal lesions after foreign body removal].

    Science.gov (United States)

    Haydon, P

    1983-09-01

    The effect of Solcoseryl on the healing rate of corneal lesions after foreign body removal was assessed in a double-blind study. Solcoseryl is a protein-free hemodialysate which is widely used to stimulate tissue repair processes. The healing rate was determined by means of photodocumentation which was complete in 82 out of 92 cases. The Solcoseryl group showed in significantly faster healing rate and a lower tendency to development of corneal opacities than the control group. No side-effects were observed which could be attributed to either of the drugs used in the study.

  1. Experiment to measure oxygen opacity at high density and temperature

    Science.gov (United States)

    Keiter, Paul; Mussack, Katie; Orban, Chris; Colgan, James; Ducret, Jean-Eric; Fontes, Christopher J.; Guzik, Joyce Ann; Heeter, Robert F.; Kilcrease, Dave; Le Pennec, Maelle; Mancini, Roberto; Perry, Ted; Turck-Chièze, Sylvaine; Trantham, Matt

    2017-06-01

    In recent years, there has been a debate over the abundances of heavy elements (Z >2) in the solar interior. Recent solar atmosphere models [Asplund 2009] find a significantly lower abundance for C, N, and O compared to models used roughly a decade ago. This discrepancy has led to an investigation of opacities through laboratory experiments and improved opacity models for many of the larger contributors to the sun’s opacity, including iron and oxygen. Recent opacity measurements of iron disagree with opacity model predictions [Bailey et al, 2015]. Although these results are still controversial, repeated scrutiny of the experiment and data has not produced a conclusive reason for the discrepancy. New models have been implemented in the ATOMIC opacity code for C, O and Fe to address the solar abundance issue [Colgan, 2013]. Armstrong et al [2014] have also implemented changes in the ATOMIC code for low-Z elements. However, no data currently exists to test the low-Z material models in the regime relevant to the solar convection zone. We present an experimental design using the opacity platform developed at the National Ignition Facility to study the oxygen opacity at densities and temperatures near the solar convection zone conditions.This work is funded by the U.S. DOE, through the NNSA-DS and SC-OFES Joint Program in HEDPLP, grant No. DE-NA0001840, and the NLUF Program, grant No. DE-NA0000850, and through LLE, University of Rochester by the NNSA/OICF under Agreement No. DE-FC52-08NA28302.

  2. Analytical expressions for radiative opacities of low Z plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rubiano, J G; Martel, P; Gil, J M; Rodriguez, R; Florido, R; Mendoza, M A [Departamento de Fisica, Universidad de Las Palmas de GC, Las Palmas de GC (Spain); Minguez, E, E-mail: jgarcia@dfis.ulpgc.e [Instituto de Fusion Nuclear (DENIM), Universidad Politecnica de Madrid, Madrid (Spain)

    2010-08-01

    In this work we obtain analytical expressions for the radiative opacity of several low Z plasmas (He, Li, Be, and B) in a wide range of temperatures and densities. These formulas are obtained by fitting the proposed expression to mean opacities data calculated by using the code ABAKO/ RAPCAL. This code computes the radiative properties of plasmas, both in LTE and NLTE conditions, under the detailed-level-accounting approach. It has been successfully validated in the range of interest in previous works.

  3. [Methods for sealing of corneal perforations].

    Science.gov (United States)

    Samoilă, O; Totu, Lăcrămioara; Călugăru, M

    2012-01-01

    A variety of corneal pathology can lead to corneal ulcers and perforations. A deep corneal ulcer may need surgical treatment to allow good volume restoration and reepithelisation. Corneal perforation must be sealed and when the perforation is large, the task of repairing the defect can be underwhelming. The elegant solution is the corneal transplant, but this is not always readily available, especially in undeveloped countries. We present here two cases with different solutions to seal the perforated cornea: the first one has a large peripheral defect and it is successfully sealed with scleral patch and the second one is central with small perforation and is successfully sealed with multilayered amniotic membrane. Both cases are followed for over 12 months and demonstrate good corneal restoration (both on clinical examination and corneal topography). Sclera and amniotic membrane can be used to seal corneal defects when corneal transplant is not readily available.

  4. Corneal collagen crosslinking: a systematic review.

    Science.gov (United States)

    Sorkin, Nir; Varssano, David

    2014-01-01

    Keratoconus (KCN) is an ectatic disorder with progressive corneal thinning and a clinical picture of corneal protrusion, progressive irregular astigmatism, corneal fibrosis and visual deterioration. Other ectatic corneal disorders include: post-LASIK ectasia (PLE) and pellucid marginal degeneration (PMD). Corneal crosslinking (CXL) is a procedure whereby riboflavin sensitization with ultraviolet A radiation induces stromal crosslinks. This alters corneal biomechanics, causing an increase in corneal stiffness. In recent years, CXL has been an established treatment for the arrest of KCN, PLE and PMD progression. CXL has also been shown to be effective in the treatment of corneal infections, chemical burns, bullous keratopathy and other forms of corneal edema. This is a current review of CXL - its biomechanical principles, the evolution of CXL protocols in the past, present and future, indications for treatment, treatment efficacy and safety.

  5. Saccade amplitude disconjugacy induced by aniseikonia: role of monocular depth cues.

    Science.gov (United States)

    Pia Bucci, M; Kapoula, Z; Eggert, T

    1999-09-01

    The conjugacy of saccades is rapidly modified if the images are made unequal for the two eyes. Disconjugacy persists even in the absence of disparity which indicates learning. Binocular visual disparity is a major cue to depth and is believed to drive the disconjugacy of saccades to aniseikonic images. The goal of the present study was to test whether monocular depth cues can also influence the disconjugacy of saccades. Three experiments were performed in which subjects were exposed for 15-20 min to a 10% image size inequality. Three different images were used: a grid that contained a single monocular depth cue strongly indicating a frontoparallel plane; a random-dot pattern that contained a less prominent monocular depth cue (absence of texture gradient) which also indicates the frontoparallel plane; and a complex image with several overlapping geometric forms that contained a variety of monocular depth cues. Saccades became disconjugate in all three experiments. The disconjugacy was larger and more persistent for the experiment using the random-dot pattern that had the least prominent monocular depth cues. The complex image which had a large variety of monocular depth cues produced the most variable and less persistent disconjugacy. We conclude that the monocular depth cues modulate the disconjugacy of saccades stimulated by the disparity of aniseikonic images.

  6. Corneal Topographic Changes After Eyelid Ptosis Surgery.

    Science.gov (United States)

    Savino, Gustavo; Battendieri, Remo; Riso, Monica; Traina, Salvatore; Poscia, Andrea; DʼAmico, Giovanni; Caporossi, Aldo

    2016-04-01

    To evaluate the corneal topography and the topographic changes after ptosis surgery on patients affected by congenital and acquired blepharoptosis. Twenty eyes of 17 patients affected by acquired and congenital ptosis underwent surgical correction through anterior levator complex tightening. Computerized tomography (Syrius Sistem; CSO) was used to analyze any change in corneal astigmatism (CYL), simulated keratometry, anterior corneal symmetry index front, apical keratometry front, and central corneal thickness. Visual acuity, margin reflex distance, and levator function were also measured. After surgical ptosis repair, corneal topography demonstrated a reduction in average keratometry of 0.15 ± 0.47 diopters (D) and in corneal astigmatism of 0.26 ± 1.12 D. Significant differences were found in apical keratometry front (-1.84 ± 1.76 D) and in best-corrected visual acuity (-0.18 ± 0.06 logMAR) in the postoperative examinations. Central corneal thickness did not show significant differences between preoperative and postoperative examinations. Postoperative topographic maps showed a reduction of symmetry index front (0.10 ± 0.64 D). Eyelid ptosis modifies anterior corneal surface inducing refractive errors and modifying corneal astigmatism in patients, thus affecting the quality of vision. The surgical correction of blepharoptosis induces anterior corneal surface modification, restoring corneal symmetry and regular corneal astigmatism. Postoperative corneal topography showed normal corneal contours.

  7. Patching for corneal abrasion.

    Science.gov (United States)

    Lim, Chris H L; Turner, Angus; Lim, Blanche X

    2016-07-26

    Published audits have demonstrated that corneal abrasions are a common presenting eye complaint. Eye patches are often recommended for treating corneal abrasions despite the lack of evidence for their use. This systematic review was conducted to determine the effects of the eye patch when used to treat corneal abrasions. The objective of this review was to assess the effects of patching for corneal abrasion on healing and pain relief. We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2016), EMBASE (January 1980 to May 2016), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to May 2016), System for Information on Grey Literature in Europe (OpenGrey) (January 1995 to May 2016), 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 9 May 2016. We also searched the reference lists of included studies, unpublished 'grey' literature and conference proceedings and contacted pharmaceutical companies for details of unpublished trials. We included randomised and quasi-randomised controlled trials that compared patching the eye with no patching to treat simple corneal abrasions. Two authors independently assessed the risk of bias and extracted data. Investigators were contacted for further information regarding the quality of trials. The primary outcome was healing at 24, 48 and 72 hours while secondary outcomes included measures of pain, quality of life and adverse effects. We graded the certainty of the evidence using GRADE. We included 12 trials which

  8. Opacity spectra of silicon and carbon in ICF plasmas

    Science.gov (United States)

    Benredjem, D.; Calisti, A.; Ferri, S.; Gilleron, F.; Mondet, G.; Pain, J.-C.

    2017-03-01

    The knowledge of opacity is very important when one investigates the radiative properties of ICF and astrophysical plasmas. Germanium and silicon are good candidates as dopants in the ablator of some ICF schemes (LMJ in France, NIF at Livermore). In this work we calculate the opacity spectra of silicon and carbon mixtures. Two competitive methods were used. The first one is based on a detailed line calculation in which the atomic database is provided by the MCDF code. A lineshape code based on a fast algorithm was then adapted to the calculation of opacity profiles. All major line broadening mechanisms, including Zeeman splitting and Stark effect, are taken into account. This approach provides accurate opacity spectra but becomes rapidly prohibitive when the number of lines is large. To account for systems involving many ionic stages and thousands of lines, a second approach combines detailed line calculations and statistical calculations. This approach necessitates much smaller calculation times than the first one and is then more appropriate for extensive calculations. The monochromatic opacity and the Rosseland and Planck mean opacities are calculated for relevant densities and temperatures.

  9. Computational design of short pulse laser driven iron opacity experiments

    Science.gov (United States)

    Martin, M. E.; London, R. A.; Goluoglu, S.; Whitley, H. D.

    2017-02-01

    The resolution of current disagreements between solar parameters calculated from models and observations would benefit from the experimental validation of theoretical opacity models. Iron's complex ionic structure and large contribution to the opacity in the radiative zone of the sun make iron a good candidate for validation. Short pulse lasers can be used to heat buried layer targets to plasma conditions comparable to the radiative zone of the sun, and the frequency dependent opacity can be inferred from the target's measured x-ray emission. Target and laser parameters must be optimized to reach specific plasma conditions and meet x-ray emission requirements. The HYDRA radiation hydrodynamics code is used to investigate the effects of modifying laser irradiance and target dimensions on the plasma conditions, x-ray emission, and inferred opacity of iron and iron-magnesium buried layer targets. It was determined that plasma conditions are dominantly controlled by the laser energy and the tamper thickness. The accuracy of the inferred opacity is sensitive to tamper emission and optical depth effects. Experiments at conditions relevant to the radiative zone of the sun would investigate the validity of opacity theories important to resolving disagreements between solar parameters calculated from models and observations.

  10. Corneal collagen cross-linking

    Directory of Open Access Journals (Sweden)

    Jankov II Mirko

    2010-01-01

    Full Text Available Corneal collagen cross-linking (CXL with riboflavin and ultraviolet-A (UVA is a new technique of corneal tissue strengthening by using riboflavin as a photosensitizer and UVA to increase the formation of intra- and interfibrillar covalent bonds by photosensitized oxidation. Keratocyte apoptosis in the anterior segment of the corneal stroma all the way down to a depth of about 300 microns has been described and a demarcation line between the treated and untreated cornea has been clearly shown. It is important to ensure that the cytotoxic threshold for the endothelium has not been exceeded by strictly respecting the minimal corneal thickness. Confocal microscopy studies show that repopulation of keratocytes is already visible 1 month after the treatment, reaching its pre-operative quantity and quality in terms of functional morphology within 6 months after the treatment. The major indication for the use of CXL is to inhibit the progression of corneal ectasias, such as keratoconus and pellucid marginal degeneration. CXL may also be effective in the treatment and prophylaxis of iatrogenic keratectasia, resulting from excessively aggressive photoablation. This treatment has also been used to treat infectious corneal ulcers with apparent favorable results. Combination with other treatments, such as intracorneal ring segment implantation, limited topography-guided photoablation and conductive keratoplasty have been used with different levels of success.

  11. Recursive method for opacity expansion at finite temperature%Recursive method for opacity expansion at finite temperature

    Institute of Scientific and Technical Information of China (English)

    刘嘉; 康忠波; 王恩科

    2011-01-01

    Using a reaction operator approach, we derive the multiple-scattering induced gluon number distribution function to all orders in powers of opacity at finite temperature. The detailed balance effect is analyzed by taking into account both gluon emission a

  12. Excimer laser phototherapeutic keratectomy in conjunction with mitomycin C in corneal macular and granular dystrophies

    Directory of Open Access Journals (Sweden)

    Erdem Yuksel

    2016-04-01

    Full Text Available ABSTRACT Purpose: To evaluate the visual outcomes, recurrence patterns, safety, and efficacy of excimer laser phototherapeutic keratectomy (PTK in conjunction with mitomycin C (MMC for corneal macular and granular diystrophies. Methods: The patients were divided into two groups. Group 1 included patients with macular corneal dystrophy (MCD that caused superficial corneal plaque opacities, and Group 2 included patients with granular corneal dystrophy (GCD. Patients in both groups were pre-, peri-, and postoperatively evaluated. The groups were compared in terms of uncorrected visual acuity (VA, best spectacle-corrected VA, presence of mild or significant recurrence, and time of recurrence. Results: Eighteen eyes (nine with MCD and nine with GCD of 18 patients (10 men and eight women were included. PTK was performed for each eye that was included in this study. The mean ablation amount was 117.8 ± 24.4 µm and 83.5 ± 45.7 µm in MCD and GCD, respectively, (p=0.18. The postoperative improvement of the mean VA was similar between the two groups before recurrences (p>0.43 and after recurrences (p>0.71. There were no statistically significant differences in the recurrence rate and the recurrence-free period for any recurrence type. Conclusion: PTK was an effective, safe, and minimally invasive procedure for patients with MCD and GCD. PTK in conjunction with MMC was similarly effective for both groups in terms of recurrence and visual outcomes.

  13. Monocular 3D display unit using soft actuator for parallax image shift

    Science.gov (United States)

    Sakamoto, Kunio; Kodama, Yuuki

    2010-11-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax images. But conventional image shift mechanism is heavy because of its linear actuator system. To improve this problem, we developed a light-weight 3D vision unit for presenting monocular stereoscopic images using a soft linear actuator made of a polypyrrole film.

  14. Light-weight monocular display unit for 3D display using polypyrrole film actuator

    Science.gov (United States)

    Sakamoto, Kunio; Ohmori, Koji

    2010-10-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax images. But conventional image shift mechanism is heavy because of its linear actuator system. To improve this problem, we developed a light-weight 3D vision unit for presenting monocular stereoscopic images using a polypyrrole linear actuator.

  15. Novel approach for mobile robot localization using monocular vision

    Science.gov (United States)

    Zhong, Zhiguang; Yi, Jianqiang; Zhao, Dongbin; Hong, Yiping

    2003-09-01

    This paper presents a novel approach for mobile robot localization using monocular vision. The proposed approach locates a robot relative to the target to which the robot moves. Two points are selected from the target as two feature points. Once the coordinates in an image of the two feature points are detected, the position and motion direction of the robot can be determined according to the detected coordinates. Unlike those reported geometry pose estimation or landmarks matching methods, this approach requires neither artificial landmarks nor an accurate map of indoor environment. It needs less computation and can simplify greatly the localization problem. The validity and flexibility of the proposed approach is demonstrated by experiments performed on real images. The results show that this new approach is not only simple and flexible but also has high localization precision.

  16. A low cost PSD-based monocular motion capture system

    Science.gov (United States)

    Ryu, Young Kee; Oh, Choonsuk

    2007-10-01

    This paper describes a monocular PSD-based motion capture sensor to employ with commercial video game systems such as Microsoft's XBOX and Sony's Playstation II. The system is compact, low-cost, and only requires a one-time calibration at the factory. The system includes a PSD(Position Sensitive Detector) and active infrared (IR) LED markers that are placed on the object to be tracked. The PSD sensor is placed in the focal plane of a wide-angle lens. The micro-controller calculates the 3D position of the markers using only the measured intensity and the 2D position on the PSD. A series of experiments were performed to evaluate the performance of our prototype system. From the experimental results we see that the proposed system has the advantages of the compact size, the low cost, the easy installation, and the high frame rates to be suitable for high speed motion tracking in games.

  17. Markerless monocular tracking system for guided external eye surgery.

    Science.gov (United States)

    Monserrat, C; Rupérez, M J; Alcañiz, M; Mataix, J

    2014-12-01

    This paper presents a novel markerless monocular tracking system aimed at guiding ophthalmologists during external eye surgery. This new tracking system performs a very accurate tracking of the eye by detecting invariant points using only textures that are present in the sclera, i.e., without using traditional features like the pupil and/or cornea reflections, which remain partially or totally occluded in most surgeries. Two known algorithms that compute invariant points and correspondences between pairs of images were implemented in our system: Scalable Invariant Feature Transforms (SIFT) and Speed Up Robust Features (SURF). The results of experiments performed on phantom eyes show that, with either algorithm, the developed system tracks a sphere at a 360° rotation angle with an error that is lower than 0.5%. Some experiments have also been carried out on images of real eyes showing promising behavior of the system in the presence of blood or surgical instruments during real eye surgery.

  18. Monocular vision based navigation method of mobile robot

    Institute of Scientific and Technical Information of China (English)

    DONG Ji-wen; YANG Sen; LU Shou-yin

    2009-01-01

    A trajectory tracking method is presented for the visual navigation of the monocular mobile robot. The robot move along line trajectory drawn beforehand, recognized and stop on the stop-sign to finish special task. The robot uses a forward looking colorful digital camera to capture information in front of the robot, and by the use of HSI model partition the trajectory and the stop-sign out. Then the "sampling estimate" method was used to calculate the navigation parameters. The stop-sign is easily recognized and can identify 256 different signs. Tests indicate that the method can fit large-scale intensity of brightness and has more robustness and better real-time character.

  19. Monocular Obstacle Detection for Real-World Environments

    Science.gov (United States)

    Einhorn, Erik; Schroeter, Christof; Gross, Horst-Michael

    In this paper, we present a feature based approach for monocular scene reconstruction based on extended Kaiman filters (EKF). Our method processes a sequence of images taken by a single camera mounted in front of a mobile robot. Using various techniques we are able to produce a precise reconstruction that is almost free from outliers and therefore can be used for reliable obstacle detection and avoidance. In real-world field tests we show that the presented approach is able to detect obstacles that can not be seen by other sensors, such as laser range finders. Furthermore, we show that visual obstacle detection combined with a laser range finder can increase the detection rate of obstacles considerably, allowing the autonomous use of mobile robots in complex public and home environments.

  20. Monocular Visual Deprivation Suppresses Excitability in Adult Human Visual Cortex

    DEFF Research Database (Denmark)

    Lou, Astrid Rosenstand; Madsen, Kristoffer Hougaard; Paulson, Olaf Bjarne

    2011-01-01

    The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we...... employed TMS to trace plastic changes in adult visual cortex before, during, and after 48 h of monocular deprivation (MD) of the right dominant eye. In healthy adult volunteers, MD-induced changes in visual cortex excitability were probed with paired-pulse TMS applied to the left and right occipital cortex....... Stimulus–response curves were constructed by recording the intensity of the reported phosphenes evoked in the contralateral visual field at range of TMS intensities. Phosphene measurements revealed that MD produced a rapid and robust decrease in cortical excitability relative to a control condition without...

  1. Monocular 3D scene reconstruction at absolute scale

    Science.gov (United States)

    Wöhler, Christian; d'Angelo, Pablo; Krüger, Lars; Kuhl, Annika; Groß, Horst-Michael

    In this article we propose a method for combining geometric and real-aperture methods for monocular three-dimensional (3D) reconstruction of static scenes at absolute scale. Our algorithm relies on a sequence of images of the object acquired by a monocular camera of fixed focal setting from different viewpoints. Object features are tracked over a range of distances from the camera with a small depth of field, leading to a varying degree of defocus for each feature. Information on absolute depth is obtained based on a Depth-from-Defocus approach. The parameters of the point spread functions estimated by Depth-from-Defocus are used as a regularisation term for Structure-from-Motion. The reprojection error obtained from bundle adjustment and the absolute depth error obtained from Depth-from-Defocus are simultaneously minimised for all tracked object features. The proposed method yields absolutely scaled 3D coordinates of the scene points without any prior knowledge about scene structure and camera motion. We describe the implementation of the proposed method both as an offline and as an online algorithm. Evaluating the algorithm on real-world data, we demonstrate that it yields typical relative scale errors of a few per cent. We examine the influence of random effects, i.e. the noise of the pixel grey values, and systematic effects, caused by thermal expansion of the optical system or by inclusion of strongly blurred images, on the accuracy of the 3D reconstruction result. Possible applications of our approach are in the field of industrial quality inspection; in particular, it is preferable to stereo cameras in industrial vision systems with space limitations or where strong vibrations occur.

  2. Corneal stromal dystrophies: a clinical pathologic study

    Directory of Open Access Journals (Sweden)

    Elvira Barbosa Abreu

    2012-12-01

    Full Text Available INTRODUCTION: Corneal dystrophy is defined as bilateral and symmetric primary corneal disease, without previous associated ocular inflammation. Corneal dystrophies are classified according to the involved corneal layer in superficial, stromal, and posterior dystrophy. Incidence of each dystrophy varies according to the geographic region studied. PURPOSE: To evaluate the prevalence of stromal corneal dystrophies among corneal buttons specimens obtained by penetrating keratoplasty (PK in an ocular pathology laboratory and to correlate the diagnosis with patient age and gender. METHODS: Corneal button cases of penetrating keratoplasty from January-1996 to May-2009 were retrieved from the archives of The Henry C. Witelson Ophthalmic Pathology Laboratory and Registry, Montreal, Canada. The cases with histopathological diagnosis of stromal corneal dystrophies were stained with special stains (Peroxid acid Schiff, Masson trichrome, Congo red analyzed under polarized light, and alcian blue for classification and correlated with epidemiological information (age at time of PK and gender from patients' file. RESULTS: 1,300 corneal buttons cases with clinical diagnose of corneal dystrophy were retrieved. Stromal corneal dystrophy was found in 40 (3.1% cases. Lattice corneal dystrophy was the most prevalent with 26 cases (65%. Nineteen were female (73.07% and the PK was performed at average age of 59.3 years old. Combined corneal dystrophy was found in 8 (20% cases, 5 (62.5% of them were female and the average age of the penetrating keratoplasty was 54.8 years old. Granular corneal dystrophy was represented by 5 (12.5% cases, and 2 (40% of them were female. Penetrating keratoplasty was performed at average age of 39.5 years old in granular corneal dystrophy cases. Macular corneal dystrophy was present in only 1 (2.5% case, in a 36 years old female. CONCLUSION: Systematic histopathological approach and evaluation, including special stains in all stromal

  3. Evaluation of Factors Limiting Corneal Donation.

    Science.gov (United States)

    Röck, Daniel; Wude, Johanna; Yoeruek, Efdal; Bartz-Schmidt, Karl Ulrich; Röck, Tobias

    2016-11-15

    BACKGROUND This study aimed to investigate factors limiting corneal donation at the University Hospital Tübingen. MATERIAL AND METHODS We retrospectively studied all hospital deaths from January 2012 to December 2015, considering each deceased patient as a potential corneal donor. During this period an ophthalmic resident managed corneal donor procurement on a full-time basis. Various factors limiting corneal donation were examined. RESULTS Among the 3412 deaths, 2937 (86.1%) displayed nonfulfillment of corneal donation. Consent for corneal donation was obtained in 475 cases (13.9%). The mean annual corneal donation rate was 13.9 donors per 100 deaths (range: 11.2-17.8). The leading causes of nonfulfillment of corneal donations were refusal to donate (49.8%, 1698 cases) and medical contraindications (23.6%, 805 cases). After next-of-kin interview of 2173 potential donors (109 potential donors were excluded because of logistical problems), willingness to participate in corneal donation was present in 475 cases (21.9%), whereas in 1698 cases (78.1%) corneal donation was refused. CONCLUSIONS Our study showed refusal to donate is the most important factor limiting corneal donation. It seems that increasing the knowledge of people about corneal donation through public education and media are necessary to address the corneal shortage.

  4. Corneal Biomechanical Findings in Contact Lens Induced Corneal Warpage

    Science.gov (United States)

    Letafatnejad, Mojgan; Beheshtnejad, Amir Hooshang; Ghaffary, Seyed Reza; Hassanpoor, Narges; Yaseri, Mehdi

    2016-01-01

    Purpose. To evaluate the difference in biomechanical properties between contact lens induced corneal warpage and normal and keratoconic eyes. Method. Prospective observational case control study, where 94 eyes of 47 warpage suspicious and 46 eyes of 23 keratoconic patients were included. Warpage suspected cases were followed until a definite diagnosis was made (warpage, normal, or keratoconus). Results. 44 eyes of 22 patients had contact lens related corneal warpage. 46 eyes of 23 people were diagnosed as nonwarpage normal eyes. 46 eyes of 23 known keratoconus patients were included for comparison. The mean age of the participants was 23.8 ± 3.8 years, and 66.2% of the subjects were female. The demographic and refractive data were not different between warpage and normal groups but were different in the keratoconus group. The biomechanical properties (corneal hysteresis or CH and corneal resistance factor or CRF) were different with the highest value in the warpage group followed by normal and keratoconus groups. CRF was 10.08 ± 1.75, 9.23 ± 1.22, and 7.38 ± 2.14 and CH was 10.21 ± 1.57, 9.59 ± 1.21, and 8.69 ± 2.34 in the warpage, normal, and keratoconus groups, respectively. Conclusion. Corneal biomechanics may be different in people who develop contact lens induced warpage. PMID:27688908

  5. Effective spherical aberration of the cornea as a quantitative descriptor in corneal topography.

    Science.gov (United States)

    Seiler, T; Reckmann, W; Maloney, R K

    1993-01-01

    Following excimer laser photorefractive keratectomy and other refractive surgical procedures, complaints of halos, glare, and monocular diplopia are common. These procedures increase the asphericity of the cornea, which may cause the optical distortions. We used ray tracing techniques to estimate the longitudinal monochromatic aberration of the cornea from the measured corneal topography (effective spherical aberration) in 15 normal eyes with varying degrees of astigmatism and in ten eyes after photorefractive keratectomy. Best spherical corrected visual acuity in the astigmatic eyes was highly correlated with effective spherical aberration (r = -0.9527, P < .001). In the eyes that had photorefractive keratectomy, the effective spherical aberration was highly correlated with measured glare visual acuity (r = 0.875, P < .002). These results suggest that effective spherical aberration is a valuable topographic measure that provides information about the optical performance of aspheric corneas.

  6. Reconstruction of Rabbit Corneal Layer Composed of Corneal Fibroblasts and Corneal Epithelium on the Lyophilized Amniotic Membrane

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Many researchers have employed the cryopreserved amniotic membrane(CAM) and corneal epithelial cells in the treatment of a severely damaged burned cornea, with corneal epithelial cells cultured on an amniotic membrane (AM). The lyophilized amniotic membrane (LAM) has a higher graft take and a longer shelf life; it is easier to store and safer because of gamma irradiation. Two Teflon rings(Ahn's supporter) were made for culturing the cells on the LAM, and were then used to support the LAM. To reconstruct a corneal layer composed of corneal fibroblasts and epithelium, the corneal fibroblasts were first cultivated on the stromal side of LAM for five days, followed by epithelial cells culture on the epithelial side, by using the air-liquid interface culture. The reconstructed corneal layer composed of corneal fibroblasts and corneal epithelial cells has a much healthier basal layer of corneal epithelium than the reconstructed corneal epithelium, which was got by using only corneal epithelial cells, and resembles the epithelium of normal corneas, without the horny layer. Thus, the reconstruction of the corneal layer by using a LAM is considered to be a good in vitro model, not only for its application in toxicological test kits, but also for transplantation in patients with a severely damaged cornea.

  7. Effect of field of view and monocular viewing on angular size judgements in an outdoor scene

    Science.gov (United States)

    Denz, E. A.; Palmer, E. A.; Ellis, S. R.

    1980-01-01

    Observers typically overestimate the angular size of distant objects. Significantly, overestimations are greater in outdoor settings than in aircraft visual-scene simulators. The effect of field of view and monocular and binocular viewing conditions on angular size estimation in an outdoor field was examined. Subjects adjusted the size of a variable triangle to match the angular size of a standard triangle set at three greater distances. Goggles were used to vary the field of view from 11.5 deg to 90 deg for both monocular and binocular viewing. In addition, an unrestricted monocular and binocular viewing condition was used. It is concluded that neither restricted fields of view similar to those present in visual simulators nor the restriction of monocular viewing causes a significant loss in depth perception in outdoor settings. Thus, neither factor should significantly affect the depth realism of visual simulators.

  8. Reactivation of thalamocortical plasticity by dark exposure during recovery from chronic monocular deprivation

    Science.gov (United States)

    Montey, Karen L.; Quinlan, Elizabeth M.

    2015-01-01

    Chronic monocular deprivation induces severe amblyopia that is resistant to spontaneous reversal in adulthood. However, dark exposure initiated in adulthood reactivates synaptic plasticity in the visual cortex and promotes recovery from chronic monocular deprivation. Here we show that chronic monocular deprivation significantly decreases the strength of feedforward excitation and significantly decreases the density of dendritic spines throughout the deprived binocular visual cortex. Dark exposure followed by reverse deprivation significantly enhances the strength of thalamocortical synaptic transmission and the density of dendritic spines on principle neurons throughout the depth of the visual cortex. Thus dark exposure reactivates widespread synaptic plasticity in the adult visual cortex, including at thalamocortical synapses, during the recovery from chronic monocular deprivation. PMID:21587234

  9. Dynamic object recognition and tracking of mobile robot by monocular vision

    Science.gov (United States)

    Liu, Lei; Wang, Yongji

    2007-11-01

    Monocular Vision is widely used in mobile robot's motion control for its simple structure and easy using. An integrated description to distinguish and tracking the specified color targets dynamically and precisely by the Monocular Vision based on the imaging principle is the major topic of the paper. The mainline is accordance with the mechanisms of visual processing strictly, including the pretreatment and recognition processes. Specially, the color models are utilized to decrease the influence of the illumination in the paper. Some applied algorithms based on the practical application are used for image segmentation and clustering. After recognizing the target, however the monocular camera can't get depth information directly, 3D Reconstruction Principle is used to calculate the distance and direction from robot to target. To emend monocular camera reading, the laser is used after vision measuring. At last, a vision servo system is designed to realize the robot's dynamic tracking to the moving target.

  10. Apparent motion of monocular stimuli in different depth planes with lateral head movements.

    Science.gov (United States)

    Shimono, K; Tam, W J; Ono, H

    2007-04-01

    A stationary monocular stimulus appears to move concomitantly with lateral head movements when it is embedded in a stereogram representing two front-facing rectangular areas, one above the other at two different distances. In Experiment 1, we found that the extent of perceived motion of the monocular stimulus covaried with the amplitude of head movement and the disparity between the two rectangular areas (composed of random dots). In Experiment 2, we found that the extent of perceived motion of the monocular stimulus was reduced compared to that in Experiment 1 when the rectangular areas were defined only by an outline rather than by random dots. These results are discussed using the hypothesis that a monocular stimulus takes on features of the binocular surface area in which it is embedded and is perceived as though it were treated as a binocular stimulus with regards to its visual direction and visual depth.

  11. The effect of monocular depth cues on the detection of moving objects by moving observers

    National Research Council Canada - National Science Library

    Royden, Constance S; Parsons, Daniel; Travatello, Joshua

    2016-01-01

    ... and thus is an ambiguous cue. We tested whether the addition of information about the distance of objects from the observer, in the form of monocular depth cues, aided detection of moving objects...

  12. Corneal biomechanics: a review.

    Science.gov (United States)

    Piñero, David P; Alcón, Natividad

    2015-03-01

    Biomechanics is often defined as 'mechanics applied to biology'. Due to the variety and complexity of the behaviour of biological structures and materials, biomechanics is better defined as the development, extension and application of mechanics for a better understanding of physiology and physiopathology and consequently for a better diagnosis and treatment of disease and injury. Different methods for the characterisation of corneal biomechanics are reviewed in detail, including those that are currently commercially available (Ocular Response Analyzer and CorVis ST). The clinical applicability of the parameters provided by these devices are discussed, especially in the fields of glaucoma, detection of ectatic disorders and orthokeratology. Likewise, other methods are also reviewed, such as Brillouin microscopy or dynamic optical coherence tomography and others with potential application to clinical practice but not validated for in vivo measurements, such as ultrasonic elastography. Advantages and disadvantages of all these techniques are described. Finally, the concept of biomechanical modelling is revised as well as the requirements for developing biomechanical models, with special emphasis on finite element modelling.

  13. The role of monocularly visible regions in depth and surface perception.

    Science.gov (United States)

    Harris, Julie M; Wilcox, Laurie M

    2009-11-01

    The mainstream of binocular vision research has long been focused on understanding how binocular disparity is used for depth perception. In recent years, researchers have begun to explore how monocular regions in binocularly viewed scenes contribute to our perception of the three-dimensional world. Here we review the field as it currently stands, with a focus on understanding the extent to which the role of monocular regions in depth perception can be understood using extant theories of binocular vision.

  14. Corneal Decompensation after Selective Laser Trabeculoplasty

    Directory of Open Access Journals (Sweden)

    Ahmet Ozkok

    2014-01-01

    Full Text Available A 64-year-old Caucasian man referred for decreased vision after selective laser trabeculoplasty (SLT. Slit lamp examination revealed diffuse corneal edema. Despite intensive topical treatment including steroids, corneal edema did not resolve; on the contrary, it advanced to bullous keratopathy. Corneal edema after SLT is an exceptionally rare complication and in all of the previous reports edema resolved with medical treatment. To the best of our knowledge, this is the first report presenting persistent corneal edema after SLT.

  15. Progress of research on corneal collagen cross-linking for corneal melting

    Directory of Open Access Journals (Sweden)

    Ke-Ren Xiao

    2016-06-01

    Full Text Available Corneal collagen cross-linking(CXLcould increase the mechanical strength, biological stability and halt ectasia progression due to covalent bond formed by photochemical reaction between ultraviolet-A and emulsion of riboflavin between collagen fibers in corneal stroma. Corneal melting is an autoimmune related noninfectious corneal ulcer. The mechanism of corneal melting, major treatment, the basic fundamental of ultraviolet-A riboflavin induced CXL and the clinical researches status and experiment in CXL were summarized in the study.

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

    Science.gov (United States)

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

    2016-08-01

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

  17. Comparison of Subjective Refraction under Binocular and Monocular Conditions in Myopic Subjects.

    Science.gov (United States)

    Kobashi, Hidenaga; Kamiya, Kazutaka; Handa, Tomoya; Ando, Wakako; Kawamorita, Takushi; Igarashi, Akihito; Shimizu, Kimiya

    2015-07-28

    To compare subjective refraction under binocular and monocular conditions, and to investigate the clinical factors affecting the difference in spherical refraction between the two conditions. We examined thirty eyes of 30 healthy subjects. Binocular and monocular refraction without cycloplegia was measured through circular polarizing lenses in both eyes, using the Landolt-C chart of the 3D visual function trainer-ORTe. Stepwise multiple regression analysis was used to assess the relations among several pairs of variables and the difference in spherical refraction in binocular and monocular conditions. Subjective spherical refraction in the monocular condition was significantly more myopic than that in the binocular condition (p refraction (p = 0.99). The explanatory variable relevant to the difference in spherical refraction between binocular and monocular conditions was the binocular spherical refraction (p = 0.032, partial regression coefficient B = 0.029) (adjusted R(2) = 0.230). No significant correlation was seen with other clinical factors. Subjective spherical refraction in the monocular condition was significantly more myopic than that in the binocular condition. Eyes with higher degrees of myopia are more predisposed to show the large difference in spherical refraction between these two conditions.

  18. A Case of Functional (Psychogenic Monocular Hemianopia Analyzed by Measurement of Hemifield Visual Evoked Potentials

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Yoneda

    2013-12-01

    Full Text Available Purpose: Functional monocular hemianopia is an extremely rare condition, for which measurement of hemifield visual evoked potentials (VEPs has not been previously described. Methods: A 14-year-old boy with functional monocular hemianopia was followed up with Goldmann perimetry and measurement of hemifield and full-field VEPs. Results: The patient had a history of monocular temporal hemianopia of the right eye following headache, nausea and ague. There was no relative afferent pupillary defect, and a color perception test was normal. Goldmann perimetry revealed a vertical monocular temporal hemianopia of the right eye; the hemianopia on the right was also detected with a binocular visual field test. Computed tomography, magnetic resonance imaging (MRI and MR angiography of the brain including the optic chiasm as well as orbital MRI revealed no abnormalities. On the basis of these results, we diagnosed the patient's condition as functional monocular hemianopia. Pattern VEPs according to the International Society for Clinical Electrophysiology of Vision (ISCEV standard were within the normal range. The hemifield pattern VEPs for the right eye showed a symmetrical latency and amplitude for nasal and temporal hemifield stimulation. One month later, the visual field defect of the patient spontaneously disappeared. Conclusions: The latency and amplitude of hemifield VEPs for a patient with functional monocular hemianopia were normal. Measurement of hemifield VEPs may thus provide an objective tool for distinguishing functional hemianopia from hemifield loss caused by an organic lesion.

  19. Acute corneal hydrops in keratoconus

    Directory of Open Access Journals (Sweden)

    Prafulla K Maharana

    2013-01-01

    Full Text Available Acute corneal hydrops is a condition characterized by stromal edema due to leakage of aqueous through a tear in descemet membrane. The patient presents with sudden onset decrease in vision, photophobia, and pain. Corneal thinning and ectasias combined with trivial trauma to the eye mostly by eye rubbing is considered as the underlying cause. With conservative approach self-resolution takes around 2 to 3 months. Surgical intervention is required in cases of non-resolution of corneal edema to avoid complications and for early visual rehabilitation. Intracameral injection of air or gas such as perflouropropane is the most common surgical procedure done. Recent investigative modality such as anterior segment optical coherence tomography is an extremely useful tool for diagnosis, surgical planning, and postoperative follow up. Resolution of hydrops may improve the contact lens tolerance and visual acuity but most cases require keratoplasty for visual rehabilitation.

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

    Directory of Open Access Journals (Sweden)

    Carlo Cagini

    2015-01-01

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

  1. Corneal Molecular and Cellular Biology for the Refractive Surgeon: The Critical Role of the Epithelial Basement Membrane.

    Science.gov (United States)

    Marino, Gustavo K; Santhiago, Marcony R; Torricelli, Andre A M; Santhanam, Abirami; Wilson, Steven E

    2016-02-01

    To provide an overview of the recent advances concerning the corneal molecular and cellular biology processes involved in the wound healing response after excimer laser surface ablation and LASIK surgery. Literature review. The corneal wound healing response is a complex cascade of events that impacts the predictability and stability of keratorefractive surgical procedures such as photorefractive keratectomy and LASIK. The generation and persistence of corneal myofibroblasts (contractile cells with reduced transparency) arise from the interaction of cytokines and growth factors such as transforming growth factor beta and interleukin 1 produced by epithelial and stromal cells in response to the corneal injury. Myofibroblasts, and the opaque extracellular matrix they secrete into the stroma, disturb the precise distribution and spacing of collagen fibers related to corneal transparency and lead to the development of vision-limiting corneal opacity (haze). The intact epithelial basement membrane has a pivotal role as a structure that regulates corneal epithelial-stromal interactions. Thus, defective regeneration of the epithelial basement membrane after surgery, trauma, or infection leads to the development of stromal haze. The apoptotic process following laser stromal ablation, which is proportional to the level of attempted correction, leads to an early decrease in anterior keratocyte density and the diminished contribution of these non-epithelial cells of components such as perlecan and nidogen-2 required for normal regeneration of the epithelial basement membrane. Haze persists until late repair of the defective epithelial basement membrane. Defective regeneration of the epithelial basement membrane has a critical role in determining whether a cornea heals with late haze after photorefractive keratectomy or with scarring at the flap edge in LASIK. Copyright 2016, SLACK Incorporated.

  2. 225 GHz Atmospheric Opacity Measurements from Two Arctic Sites

    CERN Document Server

    Matsushita, S; Martin-Cocher, P; Asada, K; Chen, C -P; Inoue, M; Paine, S; Turner, D; Steinbring, E

    2012-01-01

    We report the latest results of 225 GHz atmospheric opacity measurements from two arctic sites; one on high coastal terrain near the Eureka weather station, on Ellesmere Island, Canada, and the other at the Summit Station near the peak of the Greenland icecap. This is a campaign to search for a site to deploy a new telescope for submillimeter Very Long Baseline Interferometry and THz astronomy in the northern hemisphere. Since 2011, we have obtained 3 months of winter data near Eureka, and about one year of data at the Summit Station. The results indicate that these sites offer a highly transparent atmosphere for observations in submillimeter wavelengths. The Summit Station is particularly excellent, and its zenith opacity at 225 GHz is statistically similar to the Atacama Large Milllimeter/submillimeter Array in Chile. In winter, the opacity at the Summit Station is even comparable to that observed at the South Pole.

  3. Age of old objects constraints on cosmic opacity

    CERN Document Server

    Holanda, R F L; Dantas, M A

    2016-01-01

    In this paper, it is proposed a cosmological model independent method to constrain the cosmic opacity. As an approach never seen before in literature, we use the ages of 32 old passive galaxies distributed over the redshift interval $0.11 < z < 1.84$ and of 9 extremely old globular clusters in M31 galaxy to obtain opacity free luminosity distance. By comparing them to the 580 distance moduli of supernovae from the so-called Union 2.1 compilation we put limits on the cosmic opacity parametrized by $\\tau(z) = \\epsilon z/(1+z)$ (for $\\epsilon =0$ the transparent universe is recovered). Considering the cosmic background radiation constraints on the spatial curvature of the Universe no significant deviation from transparency is verified.

  4. Design And First Use of the NIF Opacity Spectrometer

    Science.gov (United States)

    King, J. A.; Ross, P. W.; Huffman, E. J.; Opachich, Y. P.; Heeter, R. F.; Ahmed, M.; Liedahl, D. A.; Schneider, M. B.; Dodd, E.; Flippo, K. A.; Kline, J. L.; Lopez, F. E.; Archuleta, T. N.; Perry, T. S.

    2016-10-01

    Recent experiments at the Sandia Z facility have raised questions about models used in calculating L-shell opacities of mid-Z elements. A platform is being developed to check these results at the National Ignition Facility (NIF). The NIF experiments require a new X-ray opacity spectrometer (OpSpec) for the iron L-shell X-ray band, spanning photon energies from 540 eV - 2100 eV with a resolving power E/ ΔE >700. The design of the OpSpec and photometric calculations based on expected opacity data are also presented. First use on NIF is expected in September 2016. This work was performed by National Security Technologies, LLC, under Contract No. DE-AC52-06NA25946 with the U.S. Department of Energy. DOE/NV/25946-2891.

  5. Infrared Opacities in Dense Atmospheres of Cool White Dwarf Stars

    CERN Document Server

    Kowalski, Piotr M; Dufour, Patrick

    2016-01-01

    Dense, He-rich atmospheres of cool white dwarfs represent a challenge to the modeling. This is because these atmospheres are constituted of a dense fluid in which strong multi-atomic interactions determine their physics and chemistry. Therefore, the ideal-gas-based description of absorption is no longer adequate, which makes the opacities of these atmospheres difficult to model. This is illustrated with severe problems in fitting the spectra of cool, He-rich stars. Good description of the infrared (IR) opacity is essential for proper assignment of the atmospheric parameters of these stars. Using methods of computational quantum chemistry we simulate the IR absorption of dense He/H media. We found a significant IR absorption from He atoms (He-He-He CIA opacity) and a strong pressure distortion of the H$_2$-He collision-induced absorption (CIA). We discuss the implication of these results for interpretation of the spectra of cool stars.

  6. Fractal Particles: Titan's Thermal Structure and IR Opacity

    Science.gov (United States)

    McKay, C. P.; Rannou, P.; Guez, L.; Young, E. F.; DeVincenzi, Donald (Technical Monitor)

    1998-01-01

    Titan's haze particles are the principle opacity at solar wavelengths. Most past work in modeling these particles has assumed spherical particles. However, observational evidence strongly favors fractal shapes for the haze particles. We consider the implications of fractal particles for the thermal structure and near infrared opacity of Titan's atmosphere. We find that assuming fractal particles with the optical properties based on laboratory tholin material and with a production rate that allows for a match to the geometric albedo results in warmer troposphere and surface temperatures compared to spherical particles. In the near infrared (1-3 microns) the predicted opacity of the fractal particles is up to a factor of two less than for spherical particles. This has implications for the ability of Cassini to image Titan's surface at 1 micron.

  7. Infrared Opacities in Dense Atmospheres of Cool White Dwarf Stars

    Science.gov (United States)

    Kowalski, P. M.; Blouin, S.; Dufour, P.

    2017-03-01

    Dense, He-rich atmospheres of cool white dwarfs represent a challenge to the modeling. This is because these atmospheres are constituted of a dense fluid in which strong multi-atomic interactions determine their physics and chemistry. Therefore, the ideal-gas-based description of absorption is no longer adequate, which makes the opacities of these atmospheres difficult to model. This is illustrated with severe problems in fitting the spectra of cool, He-rich stars. Good description of the infrared (IR) opacity is essential for proper assignment of the atmospheric parameters of these stars. Using methods of computational quantum chemistry we simulate the IR absorption of dense He/H media. We found a significant IR absorption from He atoms (He-He-He CIA opacity) and a strong pressure distortion of the H2-He collision-induced absorption (CIA). We discuss the implication of these results for the interpretation of the spectra of cool stars.

  8. Verification of Opacity and Diagnosability for Pushdown Systems

    Directory of Open Access Journals (Sweden)

    Koichi Kobayashi

    2013-01-01

    Full Text Available In control theory of discrete event systems (DESs, one of the challenging topics is the extension of theory of finite-state DESs to that of infinite-state DESs. In this paper, we discuss verification of opacity and diagnosability for infinite-state DESs modeled by pushdown automata (called here pushdown systems. First, we discuss opacity of pushdown systems and prove that opacity of pushdown systems is in general undecidable. In addition, a decidable class is clarified. Next, in diagnosability, we prove that under a certain assumption, which is different from the assumption in the existing result, diagnosability of pushdown systems is decidable. Furthermore, a necessary condition and a sufficient condition using finite-state approximations are derived. Finally, as one of the applications, we consider data integration using XML (Extensible Markup Language. The obtained result is useful for developing control theory of infinite-state DESs.

  9. Content and context of monocular regions determine perceived depth in random dot, unpaired background and phantom stereograms.

    Science.gov (United States)

    Grove, Philip M; Gillam, Barbara; Ono, Hiroshi

    2002-07-01

    Perceived depth was measured for three-types of stereograms with the colour/texture of half-occluded (monocular) regions either similar to or dissimilar to that of binocular regions or background. In a two-panel random dot stereogram the monocular region was filled with texture either similar or different to the far panel or left blank. In unpaired background stereograms the monocular region either matched the background or was different in colour or texture and in phantom stereograms the monocular region matched the partially occluded object or was a different colour or texture. In all three cases depth was considerably impaired when the monocular texture did not match either the background or the more distant surface. The content and context of monocular regions as well as their position are important in determining their role as occlusion cues and thus in three-dimensional layout. We compare coincidence and accidental view accounts of these effects.

  10. Measuring the opacity of stellar interior matter in terrestrial laboratories

    Science.gov (United States)

    Bailey, James

    2015-11-01

    How does energy propagate from the core to the surface of the Sun, where it emerges to warm the Earth? Nearly a century ago Eddington recognized that the attenuation of radiation by stellar matter controls the internal structure of stars like the sun. Opacities for high energy density (HED) matter are challenging to calculate because accurate and complete descriptions of the energy levels, populations, and plasma effects such as continuum lowering and line broadening are needed for partially ionized atoms. This requires approximations, in part because billions of bound-bound and bound-free electronic transitions can contribute to the opacity. Opacity calculations, however, have never been benchmarked against laboratory measurements at stellar interior conditions. Laboratory opacity measurements were limited in the past by the challenges of creating and diagnosing sufficiently large and uniform samples at the extreme conditions found inside stars. In research conducted over more than 10 years, we developed an experimental platform on the Z facility and measured wavelength-resolved iron opacity at electron temperatures Te = 156-195 eV and densities ne = 0.7-4.0 x 1022 cm-3 - conditions very similar to the radiation/convection boundary zone within the Sun. The wavelength-dependent opacity in the 975-1775 eV photon energy range is 30-400% higher than models predict. This raises questions about how well we understand the behavior of atoms in HED plasma. These measurements may also help resolve decade-old discrepancies between solar model predictions and helioseismic observations. This talk will provide an overview of the measurements, investigations of possible errors, and ongoing experiments aimed at testing hypotheses to resolve the model-data discrepancy. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

  11. Correlations between corneal and total wavefront aberrations

    Science.gov (United States)

    Mrochen, Michael; Jankov, Mirko; Bueeler, Michael; Seiler, Theo

    2002-06-01

    Purpose: Corneal topography data expressed as corneal aberrations are frequently used to report corneal laser surgery results. However, the optical image quality at the retina depends on all optical elements of the eye such as the human lens. Thus, the aim of this study was to investigate the correlations between the corneal and total wavefront aberrations and to discuss the importance of corneal aberrations for representing corneal laser surgery results. Methods: Thirty three eyes of 22 myopic subjects were measured with a corneal topography system and a Tschernig-type wavefront analyzer after the pupils were dilated to at least 6 mm in diameter. All measurements were centered with respect to the line of sight. Corneal and total wavefront aberrations were calculated up to the 6th Zernike order in the same reference plane. Results: Statistically significant correlations (p corneal and total wavefront aberrations were found for the astigmatism (C3,C5) and all 3rd Zernike order coefficients such as coma (C7,C8). No statistically significant correlations were found for all 4th to 6th order Zernike coefficients except for the 5th order horizontal coma C18 (p equals 0.003). On average, all Zernike coefficients for the corneal aberrations were found to be larger compared to Zernike coefficients for the total wavefront aberrations. Conclusions: Corneal aberrations are only of limited use for representing the optical quality of the human eye after corneal laser surgery. This is due to the lack of correlation between corneal and total wavefront aberrations in most of the higher order aberrations. Besides this, the data present in this study yield towards an aberration balancing between corneal aberrations and the optical elements within the eye that reduces the aberration from the cornea by a certain degree. Consequently, ideal customized ablations have to take both, corneal and total wavefront aberrations, into consideration.

  12. FTS Measurements of Submillimeter-Wave Atmospheric Opacity at Pampa la Bola: III. Water Vapor, Liquid Water, and 183GHz Water Vapor Line Opacities

    Science.gov (United States)

    Matsushita, Satoki; Matsuo, Hiroshi

    2003-02-01

    Further analysis has been made on the millimeter- and submillimeter-wave (100-1600GHz or 3mm-188 μm) atmospheric opacity data taken with the Fourier Transform Spectrometer (FTS) at Pampa la Bola, 4800 m above the sea level in northern Chile, which is the site of the Atacama Large Millimeter/submillimeter Array (ALMA). Time-sequence plots of millimeter- and submillimeter-wave opacities show similar variations to each other, except for during the periods with liquid water (fog or clouds) in the atmosphere. Using millimeter- and submillimeter-wave opacity correlations under two conditions, which are affected and not affected by liquid water, we succeeded to separate the measured opacity into water vapor and liquid water opacity components. The water vapor opacity shows a good correlation with the 183GHz water vapor line opacity, which is also covered in the measured spectra. On the other hand, the liquid water opacity and the 183GHz line opacity show no correlation. S ince only the water vapor component is expected to affect the phase of interferometers significantly, and the submillimeter-wave opacity is less affected by the liquid water component, it may be possible to use the submillimeter-wave opacity for a phase correction of submillimeter interferometers.

  13. Progress in corneal wound healing.

    Science.gov (United States)

    Ljubimov, Alexander V; Saghizadeh, Mehrnoosh

    2015-11-01

    Corneal wound healing is a complex process involving cell death, migration, proliferation, differentiation, and extracellular matrix remodeling. Many similarities are observed in the healing processes of corneal epithelial, stromal and endothelial cells, as well as cell-specific differences. Corneal epithelial healing largely depends on limbal stem cells and remodeling of the basement membrane. During stromal healing, keratocytes get transformed to motile and contractile myofibroblasts largely due to activation of transforming growth factor-β (TGF-β) system. Endothelial cells heal mostly by migration and spreading, with cell proliferation playing a secondary role. In the last decade, many aspects of wound healing process in different parts of the cornea have been elucidated, and some new therapeutic approaches have emerged. The concept of limbal stem cells received rigorous experimental corroboration, with new markers uncovered and new treatment options including gene and microRNA therapy tested in experimental systems. Transplantation of limbal stem cell-enriched cultures for efficient re-epithelialization in stem cell deficiency and corneal injuries has become reality in clinical setting. Mediators and course of events during stromal healing have been detailed, and new treatment regimens including gene (decorin) and stem cell therapy for excessive healing have been designed. This is a very important advance given the popularity of various refractive surgeries entailing stromal wound healing. Successful surgical ways of replacing the diseased endothelium have been clinically tested, and new approaches to accelerate endothelial healing and suppress endothelial-mesenchymal transformation have been proposed including Rho kinase (ROCK) inhibitor eye drops and gene therapy to activate TGF-β inhibitor SMAD7. Promising new technologies with potential for corneal wound healing manipulation including microRNA, induced pluripotent stem cells to generate corneal

  14. Progress in corneal wound healing

    Science.gov (United States)

    Ljubimov, Alexander V.; Saghizadeh, Mehrnoosh

    2015-01-01

    Corneal wound healing is a complex process involving cell death, migration, proliferation, differentiation, and extracellular matrix remodeling. Many similarities are observed in the healing processes of corneal epithelial, stromal and endothelial cells, as well as cell-specific differences. Corneal epithelial healing largely depends on limbal stem cells and remodeling of the basement membrane. During stromal healing, keratocytes get transformed to motile and contractile myofibroblasts largely due to activation of transforming growth factor-β system. Endothelial cells heal mostly by migration and spreading, with cell proliferation playing a secondary role. In the last decade, many aspects of wound healing process in different parts of the cornea have been elucidated, and some new therapeutic approaches have emerged. The concept of limbal stem cells received rigorous experimental corroboration, with new markers uncovered and new treatment options including gene and microRNA therapy tested in experimental systems. Transplantation of limbal stem cell-enriched cultures for efficient re-epithelialization in stem cell deficiency and corneal injuries has become reality in clinical setting. Mediators and course of events during stromal healing have been detailed, and new treatment regimens including gene (decorin) and stem cell therapy for excessive healing have been designed. This is a very important advance given the popularity of various refractive surgeries entailing stromal wound healing. Successful surgical ways of replacing the diseased endothelium have been clinically tested, and new approaches to accelerate endothelial healing and suppress endothelial-mesenchymal transformation have been proposed including Rho kinase (ROCK) inhibitor eye drops and gene therapy to activate TGF-β inhibitor SMAD7. Promising new technologies with potential for corneal wound healing manipulation including microRNA, induced pluripotent stem cells to generate corneal epithelium, and

  15. [Corneal manifestations in systemic diseases].

    Science.gov (United States)

    Zarranz Ventura, J; De Nova, E; Moreno-Montañés, J

    2008-01-01

    Systemic diseases affecting the cornea have a wide range of manifestations. The detailed study of all pathologies that cause corneal alteration is unapproachable, so we have centered our interest in the most prevalent or characteristic of them. In this paper we have divided these pathologies in sections to facilitate their study. Pulmonar and conective tissue (like colagen, rheumatologic and idiopathic inflamatory diseases), dermatologic, cardiovascular, hematologic, digestive and hepatopancreatic diseases with corneal alteration are described. Endocrine and metabolic diseases, malnutrition and carential states are also studied, as well as some otorhinolaryngologic and genetic diseases that affect the cornea. Finally, a brief report of ocular toxicity induced by drugs is referred.

  16. The Non-local Thermodynamical Equilibrium Effects on Opacity

    Institute of Scientific and Technical Information of China (English)

    WU Ze-Qing; ZHANG Ben-Ai; QIU Yu-Bo

    2001-01-01

    Based on the detailed configuration accounting (DCA) model, a method is developed to include the resonant photoionization and the excitation-autoionization in the non-local thermodynamical equilibrium (NLTE) average atom(AA) model. Using this new model, the mean charge states and the opacity are calculated for NLTE high-Z plasmas and compared with other results. The agreement w ith AA model is poor at low electron density. The present results agree well with those of DCA model within 10%. The calculations show that the NLTE effects on opacity are strong.

  17. Model-independent constraints on the cosmic opacity

    CERN Document Server

    Holanda, R F L; Alcaniz, J S

    2012-01-01

    We use current measurements of the expansion rate $H(z)$ and cosmic background radiation bounds on the spatial curvature of the Universe to impose cosmological model-independent constraints on cosmic opacity. To perform our analyses, we compare opacity-free distance modulus from $H(z)$ data with those from two supernovae Ia compilations, namely, the Union2 and Sloan Digital Sky Survey samples. The influence of different SNe Ia light-curve fitters (SALT2 and MLCS2K2) on the results is also discussed. We find that these fitters present a significant conflict, with the MLCS2K2 method being incompatible with a flat and transparent universe.

  18. Ultra-dense Hot Low Z Line Transition Opacity Simulations

    Science.gov (United States)

    Sauvan, P.; Mínguez, E.; Gil, J. M.; Rodríguez, R.; Rubiano, J. G.; Martel, P.; Angelo, P.; Schott, R.; Philippe, F.; Leboucher-Dalimier, E.; Mancini, R.; Calisti, A.

    2002-12-01

    In this work two atomic physics models (the IDEFIX code using the dicenter model and the code based on parametric potentials ANALOP) have been used to calculate the opacities for bound-bound transitions in hot ultra-dense, low Z plasmas. These simulations are in connection with experiments carried out at LULI during the last two years, focused on bound-bound radiation. In this paper H-like opacities for aluminum and fluorine plasmas have been simulated, using both theoretical models, in a wide range of densities and temperatures higher than 200 eV.

  19. Clinical experiences of photo -therapeutic keratectomy on granular corneal dystrophy(Abstract)%角膜光學切削術治療角膜顆粒狀營養不良的臨床經驗

    Institute of Scientific and Technical Information of China (English)

    金在浩

    2001-01-01

    Six eyes (five patients ) with granular corneal dystrophies underwent photogherapeutic keratectomy (PTK) to ablate corneal opacities with using of two excimer lasers (Summit ExciMed UV 200LA and Visx Star).Follow-up range was from 6 months to 7 years (mean 3 yrs). And 5 patients were improved their corrected vision upto 20/20(20/40-20/20) within a few month after PTK except of one patient who received lamellar keratoplasty on both eyes in 15 yrs ago,underwent again two times PTKs on right eye on 14 yrs and 15 yrs later due to recurrences.There is no doubt that PTK is an advantageous and initial choice of treatment for vision improvement of granular corneal dystrophy instead of corneal grafting. Only one eye among six eyes was only developed to recurrent case.

  20. Corneal Regeneration After Photorefractive Keratectomy: A Review.

    Science.gov (United States)

    Tomás-Juan, Javier; Murueta-Goyena Larrañaga, Ane; Hanneken, Ludger

    2015-01-01

    Photorefractive keratectomy (PRK) remodels corneal stroma to compensate refractive errors. The removal of epithelium and the ablation of stroma provoke the disruption of corneal nerves and a release of several peptides from tears, epithelium, stroma and nerves. A myriad of cytokines, growth factors, and matrix metalloproteases participate in the process of corneal wound healing. Their balance will determine if reepithelization and stromal remodeling are appropriate. The final aim is to achieve corneal transparency for restoring corneal function, and a proper visual quality. Therefore, wound-healing response is critical for a successful refractive surgery. Our goal is to provide an overview into how corneal wounding develops following PRK. We will also review the influence of intraoperative application of mitomycin C, bandage contact lenses, anti-inflammatory and other drugs in preventing corneal haze and post-PRK pain. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  1. Development of a monocular vision system for robotic drilling

    Institute of Scientific and Technical Information of China (English)

    Wei-dong ZHU; Biao MEI; Guo-rui YAN; Ying-lin KE

    2014-01-01

    Robotic drilling for aerospace structures demands a high positioning accuracy of the robot, which is usually achieved through error measurement and compensation. In this paper, we report the development of a practical monocular vision system for measurement of the relative error between the drill tool center point (TCP) and the reference hole. First, the principle of relative error measurement with the vision system is explained, followed by a detailed discussion on the hardware components, software components, and system integration. The elliptical contour extraction algorithm is presented for accurate and robust reference hole detection. System calibration is of key importance to the measurement accuracy of a vision system. A new method is proposed for the simultaneous calibration of camera internal parameters and hand-eye relationship with a dedicated calibration board. Extensive measurement experiments have been performed on a robotic drilling system. Experimental results show that the measurement accuracy of the developed vision system is higher than 0.15 mm, which meets the requirement of robotic drilling for aircraft structures.

  2. Deep monocular 3D reconstruction for assisted navigation in bronchoscopy.

    Science.gov (United States)

    Visentini-Scarzanella, Marco; Sugiura, Takamasa; Kaneko, Toshimitsu; Koto, Shinichiro

    2017-07-01

    In bronchoschopy, computer vision systems for navigation assistance are an attractive low-cost solution to guide the endoscopist to target peripheral lesions for biopsy and histological analysis. We propose a decoupled deep learning architecture that projects input frames onto the domain of CT renderings, thus allowing offline training from patient-specific CT data. A fully convolutional network architecture is implemented on GPU and tested on a phantom dataset involving 32 video sequences and [Formula: see text]60k frames with aligned ground truth and renderings, which is made available as the first public dataset for bronchoscopy navigation. An average estimated depth accuracy of 1.5 mm was obtained, outperforming conventional direct depth estimation from input frames by 60%, and with a computational time of [Formula: see text]30 ms on modern GPUs. Qualitatively, the estimated depth and renderings closely resemble the ground truth. The proposed method shows a novel architecture to perform real-time monocular depth estimation without losing patient specificity in bronchoscopy. Future work will include integration within SLAM systems and collection of in vivo datasets.

  3. Global localization from monocular SLAM on a mobile phone.

    Science.gov (United States)

    Ventura, Jonathan; Arth, Clemens; Reitmayr, Gerhard; Schmalstieg, Dieter

    2014-04-01

    We propose the combination of a keyframe-based monocular SLAM system and a global localization method. The SLAM system runs locally on a camera-equipped mobile client and provides continuous, relative 6DoF pose estimation as well as keyframe images with computed camera locations. As the local map expands, a server process localizes the keyframes with a pre-made, globally-registered map and returns the global registration correction to the mobile client. The localization result is updated each time a keyframe is added, and observations of global anchor points are added to the client-side bundle adjustment process to further refine the SLAM map registration and limit drift. The end result is a 6DoF tracking and mapping system which provides globally registered tracking in real-time on a mobile device, overcomes the difficulties of localization with a narrow field-of-view mobile phone camera, and is not limited to tracking only in areas covered by the offline reconstruction.

  4. Monocular visual scene understanding: understanding multi-object traffic scenes.

    Science.gov (United States)

    Wojek, Christian; Walk, Stefan; Roth, Stefan; Schindler, Konrad; Schiele, Bernt

    2013-04-01

    Following recent advances in detection, context modeling, and tracking, scene understanding has been the focus of renewed interest in computer vision research. This paper presents a novel probabilistic 3D scene model that integrates state-of-the-art multiclass object detection, object tracking and scene labeling together with geometric 3D reasoning. Our model is able to represent complex object interactions such as inter-object occlusion, physical exclusion between objects, and geometric context. Inference in this model allows us to jointly recover the 3D scene context and perform 3D multi-object tracking from a mobile observer, for objects of multiple categories, using only monocular video as input. Contrary to many other approaches, our system performs explicit occlusion reasoning and is therefore capable of tracking objects that are partially occluded for extended periods of time, or objects that have never been observed to their full extent. In addition, we show that a joint scene tracklet model for the evidence collected over multiple frames substantially improves performance. The approach is evaluated for different types of challenging onboard sequences. We first show a substantial improvement to the state of the art in 3D multipeople tracking. Moreover, a similar performance gain is achieved for multiclass 3D tracking of cars and trucks on a challenging dataset.

  5. 3D environment capture from monocular video and inertial data

    Science.gov (United States)

    Clark, R. Robert; Lin, Michael H.; Taylor, Colin J.

    2006-02-01

    This paper presents experimental methods and results for 3D environment reconstruction from monocular video augmented with inertial data. One application targets sparsely furnished room interiors, using high quality handheld video with a normal field of view, and linear accelerations and angular velocities from an attached inertial measurement unit. A second application targets natural terrain with manmade structures, using heavily compressed aerial video with a narrow field of view, and position and orientation data from the aircraft navigation system. In both applications, the translational and rotational offsets between the camera and inertial reference frames are initially unknown, and only a small fraction of the scene is visible in any one video frame. We start by estimating sparse structure and motion from 2D feature tracks using a Kalman filter and/or repeated, partial bundle adjustments requiring bounded time per video frame. The first application additionally incorporates a weak assumption of bounding perpendicular planes to minimize a tendency of the motion estimation to drift, while the second application requires tight integration of the navigational data to alleviate the poor conditioning caused by the narrow field of view. This is followed by dense structure recovery via graph-cut-based multi-view stereo, meshing, and optional mesh simplification. Finally, input images are texture-mapped onto the 3D surface for rendering. We show sample results from multiple, novel viewpoints.

  6. Mobile Robot Hierarchical Simultaneous Localization and Mapping Using Monocular Vision

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A hierarchical mobile robot simultaneous localization and mapping (SLAM) method that allows us to obtain accurate maps was presented. The local map level is composed of a set of local metric feature maps that are guaranteed to be statistically independent. The global level is a topological graph whose arcs are labeled with the relative location between local maps. An estimation of these relative locations is maintained with local map alignment algorithm, and more accurate estimation is calculated through a global minimization procedure using the loop closure constraint. The local map is built with Rao-Blackwellised particle filter (RBPF), where the particle filter is used to extending the path posterior by sampling new poses. The landmark position estimation and update is implemented through extended Kalman filter (EKF). Monocular vision mounted on the robot tracks the 3D natural point landmarks, which are structured with matching scale invariant feature transform (SIFT) feature pairs. The matching for multi-dimension SIFT features is implemented with a KD-tree in the time cost of O(lbN). Experiment results on Pioneer mobile robot in a real indoor environment show the superior performance of our proposed method.

  7. Surgical outcome in monocular elevation deficit: A retrospective interventional study

    Directory of Open Access Journals (Sweden)

    Bandyopadhyay Rakhi

    2008-01-01

    Full Text Available Background and Aim: Monocular elevation deficiency (MED is characterized by a unilateral defect in elevation, caused by paretic, restrictive or combined etiology. Treatment of this multifactorial entity is therefore varied. In this study, we performed different surgical procedures in patients of MED and evaluated their outcome, based on ocular alignment, improvement in elevation and binocular functions. Study Design: Retrospective interventional study. Materials and Methods: Twenty-eight patients were included in this study, from June 2003 to August 2006. Five patients underwent Knapp procedure, with or without horizontal squint surgery, 17 patients had inferior rectus recession, with or without horizontal squint surgery, three patients had combined inferior rectus recession and Knapp procedure and three patients had inferior rectus recession combined with contralateral superior rectus or inferior oblique surgery. The choice of procedure was based on the results of forced duction test (FDT. Results: Forced duction test was positive in 23 cases (82%. Twenty-four of 28 patients (86% were aligned to within 10 prism diopters. Elevation improved in 10 patients (36% from no elevation above primary position (-4 to only slight limitation of elevation (-1. Five patients had preoperative binocular vision and none gained it postoperatively. No significant postoperative complications or duction abnormalities were observed during the follow-up period. Conclusion: Management of MED depends upon selection of the correct surgical technique based on employing the results of FDT, for a satisfactory outcome.

  8. Eyegaze Detection from Monocular Camera Image for Eyegaze Communication System

    Science.gov (United States)

    Ohtera, Ryo; Horiuchi, Takahiko; Kotera, Hiroaki

    An eyegaze interface is one of the key technologies as an input device in the ubiquitous-computing society. In particular, an eyegaze communication system is very important and useful for severely handicapped users such as quadriplegic patients. Most of the conventional eyegaze tracking algorithms require specific light sources, equipment and devices. In this study, a simple eyegaze detection algorithm is proposed using a single monocular video camera. The proposed algorithm works under the condition of fixed head pose, but slight movement of the face is accepted. In our system, we assume that all users have the same eyeball size based on physiological eyeball models. However, we succeed to calibrate the physiologic movement of the eyeball center depending on the gazing direction by approximating it as a change in the eyeball radius. In the gaze detection stage, the iris is extracted from a captured face frame by using the Hough transform. Then, the eyegaze angle is derived by calculating the Euclidean distance of the iris centers between the extracted frame and a reference frame captured in the calibration process. We apply our system to an eyegaze communication interface, and verified the performance through key typing experiments with a visual keyboard on display.

  9. Corneal stroma microfibrils

    KAUST Repository

    Hanlon, Samuel D.

    2015-03-01

    Elastic tissue was first described well over a hundred years ago and has since been identified in nearly every part of the body. In this review, we examine elastic tissue in the corneal stroma with some mention of other ocular structures which have been more thoroughly described in the past. True elastic fibers consist of an elastin core surrounded by fibrillin microfibrils. However, the presence of elastin fibers is not a requirement and some elastic tissue is comprised of non-elastin-containing bundles of microfibrils. Fibers containing a higher relative amount of elastin are associated with greater elasticity and those without elastin, with structural support. Recently it has been shown that the microfibrils, not only serve mechanical roles, but are also involved in cell signaling through force transduction and the release of TGF-β. A well characterized example of elastin-free microfibril bundles (EFMBs) is found in the ciliary zonules which suspend the crystalline lens in the eye. Through contraction of the ciliary muscle they exert enough force to reshape the lens and thereby change its focal point. It is believed that the molecules comprising these fibers do not turn-over and yet retain their tensile strength for the life of the animal. The mechanical properties of the cornea (strength, elasticity, resiliency) would suggest that EFMBs are present there as well. However, many authors have reported that, although present during embryonic and early postnatal development, EFMBs are generally not present in adults. Serial-block-face imaging with a scanning electron microscope enabled 3D reconstruction of elements in murine corneas. Among these elements were found fibers that formed an extensive network throughout the cornea. In single sections these fibers appeared as electron dense patches. Transmission electron microscopy provided additional detail of these patches and showed them to be composed of fibrils (~10nm diameter). Immunogold evidence clearly

  10. Corneale crosslinking voor progressieve keratoconus

    NARCIS (Netherlands)

    Wisse, Robert P L; Soeters, Nienke; Godefrooij, Daniel A.; De Koning-Tahzib, Nayyirih G.

    2016-01-01

    Keratoconus is a corneal disease with onset typically occurring during puberty or early adulthood. The cornea progressively thins and acquires a cone-like shape which negatively affects visual acuity. In the early stages, visual acuity can be corrected with glasses or contact lenses. In more

  11. Corneale crosslinking voor progressieve keratoconus

    NARCIS (Netherlands)

    Wisse, Robert P L; Soeters, Nienke; Godefrooij, Daniel A.; De Koning-Tahzib, Nayyirih G.

    2016-01-01

    Keratoconus is a corneal disease with onset typically occurring during puberty or early adulthood. The cornea progressively thins and acquires a cone-like shape which negatively affects visual acuity. In the early stages, visual acuity can be corrected with glasses or contact lenses. In more advance

  12. Terahertz sensing of corneal hydration.

    Science.gov (United States)

    Singh, Rahul S; Tewari, Priyamvada; Bourges, Jean Louis; Hubschman, Jean Pierre; Bennett, David B; Taylor, Zachary D; Lee, H; Brown, Elliott R; Grundfest, Warren S; Culjat, Martin O

    2010-01-01

    An indicator of ocular health is the hydrodyanmics of the cornea. Many corneal disorders deteriorate sight as they upset the normal hydrodynamics of the cornea. The mechanisms include the loss of endothelial pump function of corneal dystophies, swelling and immune response of corneal graft rejection, and inflammation and edema, which accompany trauma, burn, and irritation events. Due to high sensitivity to changes of water content in materials, a reflective terahertz (300 GHz and 3 THz) imaging system could be an ideal tool to measure the hydration level of the cornea. This paper presents the application of THz technology to visualize the hydration content across ex vivo porcine corneas. The corneas, with a thickness variation from 470 - 940 µm, were successfully imaged using a reflective pulsed THz imaging system, with a maximum SNR of 50 dB. To our knowledge, no prior studies have reported on the use of THz in measuring hydration in corneal tissues or other ocular tissues. These preliminary findings indicate that THz can be used to accurately sense hydration levels in the cornea using a pulsed, reflective THz imaging system.

  13. Clinical Observation of Transepithelial Corneal Collagen Cross-linking by Iontophoresis of Riboflavin in Treatment of Keratoconus

    Institute of Scientific and Technical Information of China (English)

    Na Li; Zhengjun Fan; Xiujun Peng; Xu Pang; Chunyu Tian

    2014-01-01

    Purpose: To evaluate the efficacy and safety of transepithelial collagen cross-linking by iontophoretic delivery of riboflavin in treatment of progressive keratoconus.Methods:.Eleven patients (15 eyes) with progressive kerato-conus were enrolled. After 0.1% riboflavin-distilled water so-lution was deliveried via transepithelial iontophpresis for 5 min with 1 mA current, and ultraviolet radiation (370 nm,.3 mW /cm2) was performed at a 1.5 cm distance for 30 min. The fol-low up were 6 months in all eyes. The uncorrected visual acu-ity, corrected visual acuity,endothelial cell counting, corneal thickness,.intraocular pressure, corneal curvature, corneal to-pography,.OCT and corneal opacity before and 6-month after surgery were analyzed.Results: At 6 month postoperatively, mean uncorrected visual acuity and corrected visual acuity changed from 0.36 to 0.30 and from 0.42 to 0.57 without statistical significance..The mean value of each index of corneal curvature declined with-out statistical significance.Kmax value dereased from 60.91 to 59.91, and the astigmatism declined from 3.86 to 3.19. Cen-tral corneal thickness decreased from 460.93 μm to 455.40μm,.and thinnest corneal thickness declined from 450.87 μm to 440.60 μm with no statistical significance..Intraocular pres-sure was significantly elevated from 10.85 mmHg to 12.62 mmHg. Endothelial cell count did not change significantly. No corneal haze occurred. Mean depth of corneal demarcation line was 288.46 μm at 1 month postoperatively..Conclusion:.Transepithelial corneal collagen cross-linking by iontophoresis is effective and safe in the treatment of progres-sive keratoconus, and yields stable clinical outcomes during 6-month follow up..However,.long-term follow up is urgently required. (Eye Science 2014; 29:160-164)

  14. FIRST NEW SOLAR MODELS WITH OPAS OPACITY TABLES

    Energy Technology Data Exchange (ETDEWEB)

    Le Pennec, M.; Turck-Chièze, S.; Salmon, S. [CEA/IRFU/Service d’Astrophysique, CE Saclay, F-91191 Gif sur Yvette (France); Blancard, C.; Cossé, P.; Faussurier, G.; Mondet, G. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2015-11-10

    Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However, the particular case of the Sun is still challenging. For about a decade now, the helioseismic sound-speed determination has continued to disagree with the standard solar model (SSM) prediction, questioning the reliability of this model. One of the sources of uncertainty could be in the treatment of the transport of radiation from the solar core to the surface. In this Letter, we use the new OPAS opacity tables, recently available for solar modeling, to address this issue. We discuss first the peculiarities of these tables, then we quantify their impact on the solar sound-speed and density profiles using the reduced OPAS tables taken on the grids of the OPAL ones. We use the two evolution codes, Modules for Experiments in Stellar Astrophysics and Code Liégeois d’Evolution Stellaire, that led to similar conclusions in the solar radiative zone. In comparison to commonly used OPAL opacity tables, the new solar models are computed for the most recent photospheric composition with OPAS tables and present improvements to the location of the base of the convective zone and to the description of the solar radiative zone in comparison to the helioseismic observations, even if the differences in the Rosseland mean opacity do not exceed 6%. We finally carry out a comparison to a solar model computed with the OP opacity tables.

  15. Design Parameter Studies of Emission-Based Iron Opacity Measurements

    Science.gov (United States)

    Martin, Madison E.; London, Richard A.; Goluoglu, Sedat; Whitley, Heather D.

    2016-10-01

    Opacity is a critical parameter in the transport of radiation in systems such as inertial confinement fusion capsules and stars. The resolution of current disagreements between solar models and helioseismological observations would benefit from experimental validation of theoretical opacity models. Short pulse lasers can be used to heat targets to higher temperatures and densities than long pulse lasers and pulsed power machines, thus potentially enabling access to x-ray emission spectra at conditions relevant to solar models. The radiation-hydrodynamic code HYDRA is used to investigate the effects of modifying laser energy, laser pulse length, and target dimensions on the plasma conditions, x-ray emission, and inferred opacity of a buried layer iron target. The accuracy of the opacity inference is sensitive to tamper emission and optical depth effects. An example design that reaches temperatures and densities relevant to the radiative zone of the sun while reducing optical depth and tamper emission effects will be discussed. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC.

  16. 40 CFR 75.14 - Specific provisions for monitoring opacity.

    Science.gov (United States)

    2010-07-01

    ... calendar year. (d) Diesel-fired units and dual-fuel reciprocating engine units. The owner or operator of an affected diesel-fired unit or a dual-fuel reciprocating engine unit is exempt from the opacity monitoring... unit by changing its fuel mix, the owner or operator shall install, operate, and certify a continuous...

  17. The fog of change : opacity and asperity in organizations.

    OpenAIRE

    Hannan, M.T.; Pólos, L.; Carroll, G.R.

    2003-01-01

    Initial architectural change in organizations often induces other subsequent changes, generating lengthy cascades of changes in subordinate units. This article extends a formal model of cascading organizational change by examining the implications for organizational change of the limited foresight of those who initiate such change about unit interconnections (structural opacity) and the normative restrictiveness imposed on architectural features by organizational culture (cultural asperity). ...

  18. Management of corneal bee sting

    Directory of Open Access Journals (Sweden)

    Razmjoo H

    2011-12-01

    Full Text Available Hassan Razmjoo1,2, Mohammad-Ali Abtahi1,2,4, Peyman Roomizadeh1,3, Zahra Mohammadi1,2, Seyed-Hossein Abtahi1,3,41Medical School, Isfahan University of Medical Sciences (IUMS; 2Ophthalmology Ward, Feiz Hospital, IUMS; 3Isfahan Medical Students Research Center (IMSRC, IUMS; 4Isfahan Ophthalmology Research Center (IORC, Feiz Hospital, IUMS, Isfahan, IranAbstract: Corneal bee sting is an uncommon environmental eye injury that can result in various ocular complications with an etiology of penetrating, immunologic, and toxic effects of the stinger and its injected venom. In this study we present our experience in the management of a middle-aged male with a right-sided deep corneal bee sting. On arrival, the patient was complaining of severe pain, blurry vision with acuity of 160/200, and tearing, which he had experienced soon after the injury. Firstly, we administered conventional drugs for eye injuries, including topical antibiotic, corticosteroid, and cycloplegic agents. After 2 days, corneal stromal infiltration and edema developed around the site of the sting, and visual acuity decreased to 100/200. These conditions led us to remove the stinger surgically. Within 25 days of follow-up, the corneal infiltration decreased gradually, and visual acuity improved to 180/200. We suggest a two-stage management approach for cases of corneal sting. For the first stage, if the stinger is readily accessible or primary dramatic reactions, including infiltration, especially on the visual axis, exist, manual or surgical removal would be indicated. Otherwise, we recommend conventional treatments for eye injuries. Given this situation, patients should be closely monitored for detection of any worsening. If the condition does not resolve or even deteriorates, for the second stage, surgical removal of the stinger under local or generalized anesthesia is indicated.Keywords: bee sting, stinger, cornea, removal, management, surgery

  19. FTS measurements of submillimeter-wave opacity at Pampa la Bola

    Science.gov (United States)

    Matsuo, Hiroshi; Sakamoto, Akihiro; Matsushita, Satoki

    1998-07-01

    The first measurement of submillimeter-wave atmospheric opacity spectra at the Pampa la Bola site (Northern Chile, Atacama 4800 m altitude) has been performed during the winter season using a Fourier transform spectrometer (FTS). Atmospheric emission spectra, as a function of airmass, were measured under various weather conditions. Atmospheric opacity was evaluated from sky temperature at zenith as well as from tipping measurements, which are independent measure but give consistent results. The FTS opacity measurements also show good match with 220 GHz radiometer measurements. Correlations between millimeter-wave and submillimeter-wave opacities get worse when 220 GHz opacity is larger than 0.1. Deviations from the opacity correlation at each frequency show good correlations themselves but have different relative variations at each frequency. This indicates that atmospheric transparency cannot be characterized only by millimeter-wave opacity buy requires simultaneous opacity measurements at millimeter and submillimeter-wavelengths.

  20. Turning the tide of corneal blindness.

    Science.gov (United States)

    Oliva, Matthew S; Schottman, Tim; Gulati, Manoj

    2012-01-01

    Corneal diseases represent the second leading cause of blindness in most developing world countries. Worldwide, major investments in public health infrastructure and primary eye care services have built a strong foundation for preventing future corneal blindness. However, there are an estimated 4.9 million bilaterally corneal blind persons worldwide who could potentially have their sight restored through corneal transplantation. Traditionally, barriers to increased corneal transplantation have been daunting, with limited tissue availability and lack of trained corneal surgeons making widespread keratoplasty services cost prohibitive and logistically unfeasible. The ascendancy of cataract surgical rates and more robust eye care infrastructure of several Asian and African countries now provide a solid base from which to dramatically expand corneal transplantation rates. India emerges as a clear global priority as it has the world's largest corneal blind population and strong infrastructural readiness to rapidly scale its keratoplasty numbers. Technological modernization of the eye bank infrastructure must follow suit. Two key factors are the development of professional eye bank managers and the establishment of Hospital Cornea Recovery Programs. Recent adaptation of these modern eye banking models in India have led to corresponding high growth rates in the procurement of transplantable tissues, improved utilization rates, operating efficiency realization, and increased financial sustainability. The widespread adaptation of lamellar keratoplasty techniques also holds promise to improve corneal transplant success rates. The global ophthalmic community is now poised to scale up widespread access to corneal transplantation to meet the needs of the millions who are currently blind.

  1. Turning the tide of corneal blindness

    Directory of Open Access Journals (Sweden)

    Matthew S Oliva

    2012-01-01

    Full Text Available Corneal diseases represent the second leading cause of blindness in most developing world countries. Worldwide, major investments in public health infrastructure and primary eye care services have built a strong foundation for preventing future corneal blindness. However, there are an estimated 4.9 million bilaterally corneal blind persons worldwide who could potentially have their sight restored through corneal transplantation. Traditionally, barriers to increased corneal transplantation have been daunting, with limited tissue availability and lack of trained corneal surgeons making widespread keratoplasty services cost prohibitive and logistically unfeasible. The ascendancy of cataract surgical rates and more robust eye care infrastructure of several Asian and African countries now provide a solid base from which to dramatically expand corneal transplantation rates. India emerges as a clear global priority as it has the world′s largest corneal blind population and strong infrastructural readiness to rapidly scale its keratoplasty numbers. Technological modernization of the eye bank infrastructure must follow suit. Two key factors are the development of professional eye bank managers and the establishment of Hospital Cornea Recovery Programs. Recent adaptation of these modern eye banking models in India have led to corresponding high growth rates in the procurement of transplantable tissues, improved utilization rates, operating efficiency realization, and increased financial sustainability. The widespread adaptation of lamellar keratoplasty techniques also holds promise to improve corneal transplant success rates. The global ophthalmic community is now poised to scale up widespread access to corneal transplantation to meet the needs of the millions who are currently blind.

  2. Clinical applications of corneal confocal microscopy

    Directory of Open Access Journals (Sweden)

    Mitra Tavakoli

    2008-06-01

    Full Text Available Mitra Tavakoli1, Parwez Hossain2, Rayaz A Malik11Division of Cardiovascular Medicine, University of Manchester and Manchester Royal Infirmary, Manchester, UK; 2University of Southampton, Southampton Eye Unit, Southampton General Hospital, Southampton, UKAbstract: Corneal confocal microscopy is a novel clinical technique for the study of corneal cellular structure. It provides images which are comparable to in-vitro histochemical techniques delineating corneal epithelium, Bowman’s layer, stroma, Descemet’s membrane and the corneal endothelium. Because, corneal confocal microscopy is a non invasive technique for in vivo imaging of the living cornea it has huge clinical potential to investigate numerous corneal diseases. Thus far it has been used in the detection and management of pathologic and infectious conditions, corneal dystrophies and ecstasies, monitoring contact lens induced corneal changes and for pre and post surgical evaluation (PRK, LASIK and LASEK, flap evaluations and Radial Keratotomy, and penetrating keratoplasty. Most recently it has been used as a surrogate for peripheral nerve damage in a variety of peripheral neuropathies and may have potential in acting as a surrogate marker for endothelial abnormalities.Keywords: corneal confocal microscopy, cornea, infective keratitis, corneal dystrophy, neuropathy

  3. Enhanced monocular visual odometry integrated with laser distance meter for astronaut navigation.

    Science.gov (United States)

    Wu, Kai; Di, Kaichang; Sun, Xun; Wan, Wenhui; Liu, Zhaoqin

    2014-03-11

    Visual odometry provides astronauts with accurate knowledge of their position and orientation. Wearable astronaut navigation systems should be simple and compact. Therefore, monocular vision methods are preferred over stereo vision systems, commonly used in mobile robots. However, the projective nature of monocular visual odometry causes a scale ambiguity problem. In this paper, we focus on the integration of a monocular camera with a laser distance meter to solve this problem. The most remarkable advantage of the system is its ability to recover a global trajectory for monocular image sequences by incorporating direct distance measurements. First, we propose a robust and easy-to-use extrinsic calibration method between camera and laser distance meter. Second, we present a navigation scheme that fuses distance measurements with monocular sequences to correct the scale drift. In particular, we explain in detail how to match the projection of the invisible laser pointer on other frames. Our proposed integration architecture is examined using a live dataset collected in a simulated lunar surface environment. The experimental results demonstrate the feasibility and effectiveness of the proposed method.

  4. Dichoptic training in adults with amblyopia: Additional stereoacuity gains over monocular training.

    Science.gov (United States)

    Liu, Xiang-Yun; Zhang, Jun-Yun

    2017-08-04

    Dichoptic training is a recent focus of research on perceptual learning in adults with amblyopia, but whether and how dichoptic training is superior to traditional monocular training is unclear. Here we investigated whether dichoptic training could further boost visual acuity and stereoacuity in monocularly well-trained adult amblyopic participants. During dichoptic training the participants used the amblyopic eye to practice a contrast discrimination task, while a band-filtered noise masker was simultaneously presented in the non-amblyopic fellow eye. Dichoptic learning was indexed by the increase of maximal tolerable noise contrast for successful contrast discrimination in the amblyopic eye. The results showed that practice tripled maximal tolerable noise contrast in 13 monocularly well-trained amblyopic participants. Moreover, the training further improved stereoacuity by 27% beyond the 55% gain from previous monocular training, but unchanged visual acuity of the amblyopic eyes. Therefore our dichoptic training method may produce extra gains of stereoacuity, but not visual acuity, in adults with amblyopia after monocular training. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. MONOCULAR AND BINOCULAR VISION IN THE PERFORMANCE OF A COMPLEX SKILL

    Directory of Open Access Journals (Sweden)

    Thomas Heinen

    2011-09-01

    Full Text Available The goal of this study was to investigate the role of binocular and monocular vision in 16 gymnasts as they perform a handspring on vault. In particular we reasoned, if binocular visual information is eliminated while experts and apprentices perform a handspring on vault, and their performance level changes or is maintained, then such information must or must not be necessary for their best performance. If the elimination of binocular vision leads to differences in gaze behavior in either experts or apprentices, this would answer the question of an adaptive gaze behavior, and thus if this is a function of expertise level or not. Gaze behavior was measured using a portable and wireless eye-tracking system in combination with a movement-analysis system. Results revealed that gaze behavior differed between experts and apprentices in the binocular and monocular conditions. In particular, apprentices showed less fixations of longer duration in the monocular condition as compared to experts and the binocular condition. Apprentices showed longer blink duration than experts in both, the monocular and binocular conditions. Eliminating binocular vision led to a shorter repulsion phase and a longer second flight phase in apprentices. Experts exhibited no differences in phase durations between binocular and monocular conditions. Findings suggest, that experts may not rely on binocular vision when performing handsprings, and movement performance maybe influenced in apprentices when eliminating binocular vision. We conclude that knowledge about gaze-movement relationships may be beneficial for coaches when teaching the handspring on vault in gymnastics

  6. The precision of binocular and monocular depth judgments in natural settings.

    Science.gov (United States)

    McKee, Suzanne P; Taylor, Douglas G

    2010-08-01

    We measured binocular and monocular depth thresholds for objects presented in a real environment. Observers judged the depth separating a pair of metal rods presented either in relative isolation, or surrounded by other objects, including a textured surface. In the isolated setting, binocular thresholds were greatly superior to the monocular thresholds by as much as a factor of 18. The presence of adjacent objects and textures improved the monocular thresholds somewhat, but the superiority of binocular viewing remained substantial (roughly a factor of 10). To determine whether motion parallax would improve monocular sensitivity for the textured setting, we asked observers to move their heads laterally, so that the viewing eye was displaced by 8-10 cm; this motion produced little improvement in the monocular thresholds. We also compared disparity thresholds measured with the real rods to thresholds measured with virtual images in a standard mirror stereoscope. Surprisingly, for the two naive observers, the stereoscope thresholds were far worse than the thresholds for the real rods-a finding that indicates that stereoscope measurements for unpracticed observers should be treated with caution. With practice, the stereoscope thresholds for one observer improved to almost the precision of the thresholds for the real rods.

  7. 77 FR 13997 - Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources

    Science.gov (United States)

    2012-03-08

    ... AGENCY 40 CFR Part 60 RIN 2060-AH23 Quality Assurance Requirements for Continuous Opacity Monitoring... rule titled, ``Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary....regulations.gov or in hard copy at the Procedure 3--Quality Assurance Requirements for Continuous Opacity...

  8. Differential expression of epithelial basement membrane components nidogens and perlecan in corneal stromal cells in vitro.

    Science.gov (United States)

    Santhanam, Abirami; Torricelli, Andre A M; Wu, Jiahui; Marino, Gustavo K; Wilson, Steven E

    2015-01-01

    The purpose of this study was to examine the expression of corneal epithelial basement membrane (EBM) components in different corneal stromal cell types. In vitro model systems were used to explore the expression of EBM components nidogen-1, nidogen-2, and perlecan that are the primary components in the lamina lucida and the lamina densa that defectively regenerate in corneas with stromal opacity after in -9.0 D photorefractive keratectomy (PRK). Primary rabbit corneal stromal cells were cultured using varying serum concentrations and exogenous growth factors, including fibroblast growth factor (FGF)-2 and transforming growth factor (TGF)-β1, to optimize the growth of each cell type of interest. The expression of the keratocyte-specific marker keratocan and the myofibroblast-specific marker α-smooth muscle actin (α-SMA) were analyzed with real-time PCR, western blot, and immunocytochemical staining to evaluate the specificity of the cell types and select optimal conditions (high keratocan and low α-SMA for keratocytes; low keratocan and high α-SMA for myofibroblasts; low keratocan and low α-SMA for corneal fibroblasts). The expression of the EBM components nidogen-1, nidogen-2, and perlecan was evaluated in each corneal cell type using real-time PCR, immunostaining, and western blotting. In agreement with previous studies, serum-free DMEM was found to be optimal for keratocytes, DMEM with 10% serum and 40 ng/ml FGF-2 yielded the best marker profile for corneal fibroblasts, and DMEM with 1% serum and 2 ng/ml TGF-β1 was found to be optimal for myofibroblasts. Nidogen-1 and nidogen-2 mRNAs were highly expressed in keratocytes, whereas perlecan was highly expressed in myofibroblasts. In keratocytes, nidogen-2 and perlecan proteins were expressed predominantly in intracellular compartments, whereas in myofibroblasts expression of both EBM components was observed diffusely throughout the cell. Although the perlecan mRNA levels were high in the myofibroblasts, the

  9. Visual outcome after corneal transplantation for corneal perforation and iris prolapse in 37 horses

    DEFF Research Database (Denmark)

    Henriksen, Michala de Linde; Plummer, C. E.; Mangan, B.;

    2012-01-01

    We wanted to investigate the visual outcome of horses presented with iris prolapse and treated with corneal transplantation.......We wanted to investigate the visual outcome of horses presented with iris prolapse and treated with corneal transplantation....

  10. Patterns of non-embolic transient monocular visual field loss.

    Science.gov (United States)

    Petzold, Axel; Islam, Niaz; Plant, G T

    2013-07-01

    The aim of this study was to systematically describe the semiology of non-embolic transient monocular visual field loss (neTMVL). We conducted a retrospective case note analysis of patients from Moorfields Eye Hospital (1995-2007). The variables analysed were age, age of onset, gender, past medical history or family history of migraine, eye affected, onset, duration and offset, perception (pattern, positive and negative symptoms), associated headache and autonomic symptoms, attack frequency, and treatment response to nifedipine. We identified 77 patients (28 male and 49 female). Mean age of onset was 37 years (range 14-77 years). The neTMVL was limited to the right eye in 36 % to the left in 47 % and occurred independently in either eye in 5 % of cases. A past medical history of migraine was present in 12 % and a family history in 8 %. Headache followed neTMVL in 14 % and was associated with autonomic features in 3 %. The neTMB was perceived as grey in 35 %, white in 21 %, black in 16 % and as phosphenes in 9 %. Most frequently neTMVL was patchy 20 %. Recovery of vision frequently resembled attack onset in reverse. In 3 patients without associated headache the loss of vision was permanent. Treatment with nifedipine was initiated in 13 patients with an attack frequency of more than one per week and reduced the attack frequency in all. In conclusion, this large series of patients with neTMVL permits classification into five types of reversible visual field loss (grey, white, black, phosphenes, patchy). Treatment response to nifidipine suggests some attacks to be caused by vasospasm.

  11. Determination of corneal image-forming properties from corneal topography.

    Science.gov (United States)

    Maloney, R K; Bogan, S J; Waring, G O

    1993-01-01

    Keratometry provides useful information about the cornea's image-forming properties, such as corneal astigmatism, but is inaccurate on irregular corneas. Quantitative corneal topographic information is now obtainable on irregular corneas, but is difficult for the clinician to interpret. We developed a method to determine the spherical power, astigmatism, and topographic irregularity of a cornea by finding the best-fit spherocylinder that was closest to its measured topography. Keratometric measurements and two videokeratographs were gathered prospectively on 262 normal and abnormal corneas. The best-fit measurements of spherical power, astigmatism, and topographic irregularity were reproducible with one standard deviation of 0.75 diopter or better; agreement with keratometric measurements in normal eyes was good (0.60 diopter or better). Topographic irregularity averaged 0.1 diopter on precision spheres, 0.4 diopter on 146 normal eyes, 0.8 diopter on 29 eyes after radial keratotomy, 2.0 diopters on 58 eyes after penetrating keratoplasty, and 3.0 diopters on 29 eyes with advanced keratoconus. We conclude the following: basic corneal image-forming properties can be measured from videokeratographs; the properties can be determined, by our methods, on irregular corneas in which keratometry is unreliable; and topographic irregularity provides a measure of irregular astigmatism.

  12. Genetics Home Reference: lattice corneal dystrophy type I

    Science.gov (United States)

    ... corneal dystrophy type I lattice corneal dystrophy type I Enable Javascript to view the expand/collapse boxes. ... All Close All Description Lattice corneal dystrophy type I is an eye disorder that affects the clear, ...

  13. Immunoglobulins in granular corneal dystrophy Groenouw type I

    DEFF Research Database (Denmark)

    Møller, H U; Bojsen-Møller, M; Schrøder, H D

    1993-01-01

    Three patients with granular corneal dystrophy Groenouw type I underwent corneal grafting, and cryostat sections of the corneal buttons were examined immunohistochemically for immunoglobulins. Positive results were obtained for IgG, Kappa-, and Lambda chains with immunofluorescence technique...

  14. Polar Value Analysis of Corneal Astigmatism in Intrastromal Corneal Ring Segment Implantation

    OpenAIRE

    Chang Rae Rho; Min-Ji Kim; Choun-Ki Joo

    2016-01-01

    Purpose. To evaluate surgically induced astigmatism (SIA) and the average corneal power change in symmetric intrastromal corneal ring segment (ICRS) implantation. Methods. The study included 34 eyes of 34 keratoconus patients who underwent symmetric Intacs SK ICRS implantation. The corneal pocket incision meridian was the preoperative steep meridian. Corneal power data were obtained before and 3 months after Intacs SK ICRS implantation using scanning-slit topography. Polar value analysis was ...

  15. The contribution of monocular depth cues to scene perception by pigeons.

    Science.gov (United States)

    Cavoto, Brian R; Cook, Robert G

    2006-07-01

    The contributions of different monocular depth cues to performance of a scene perception task were investigated in 4 pigeons. They discriminated the sequential depth ordering of three geometric objects in computer-rendered scenes. The orderings of these objects were specified by the combined presence or absence of the pictorial cues of relative density, occlusion, and relative size. In Phase 1, the pigeons learned the task as a direct function of the number of cues present. The three monocular cues contributed equally to the discrimination. Phase 2 established that differential shading on the objects provided an additional discriminative cue. These results suggest that the pigeon visual system is sensitive to many of the same monocular depth cues that are known to be used by humans. The theoretical implications for a comparative psychology of picture processing are considered.

  16. Refractive error and monocular viewing strengthen the hollow-face illusion.

    Science.gov (United States)

    Hill, Harold; Palmisano, Stephen; Matthews, Harold

    2012-01-01

    We measured the strength of the hollow-face illusion--the 'flipping distance' at which perception changes between convex and concave--as a function of a lens-induced 3 dioptre refractive error and monocular/binocular viewing. Refractive error and closing one eye both strengthened the illusion to approximately the same extent. The illusion was weakest viewed binocularly without refractive error and strongest viewed monocularly with it. This suggests binocular cues disambiguate the illusion at greater distances than monocular cues, but that both are disrupted by refractive error. We argue that refractive error leaves the ambiguous low-spatial-frequency shading information critical to the illusion largely unaffected while disrupting other, potentially disambiguating, depth/distance cues.

  17. A new combination of monocular and stereo cues for dense disparity estimation

    Science.gov (United States)

    Mao, Miao; Qin, Kaihuai

    2013-07-01

    Disparity estimation is a popular and important topic in computer vision and robotics. Stereo vision is commonly done to complete the task, but most existing methods fail in textureless regions and utilize numerical methods to interpolate into these regions. Monocular features are usually ignored, which may contain helpful depth information. We proposed a novel method combining monocular and stereo cues to compute dense disparities from a pair of images. The whole image regions are categorized into reliable regions (textured and unoccluded) and unreliable regions (textureless or occluded). Stable and accurate disparities can be gained at reliable regions. Then for unreliable regions, we utilize k-means to find the most similar reliable regions in terms of monocular cues. Our method is simple and effective. Experiments show that our method can generate a more accurate disparity map than existing methods from images with large textureless regions, e.g. snow, icebergs.

  18. EVIDENCE FOR ENVIRONMENTAL CHANGES IN THE SUBMILLIMETER DUST OPACITY

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Peter G.; Roy, Arabindo; Miville-Deschenes, Marc-Antoine [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Bontemps, Sylvain [Observatoire de Bordeaux, BP 89, F-33270 Floirac (France); Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip [Department of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff, CF24 3AA (United Kingdom); Bock, James J. [Jet Propulsion Laboratory, Pasadena, CA 91109-8099 (United States); Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Devlin, Mark J.; Dicker, Simon R.; Klein, Jeff [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Gundersen, Joshua O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Carol Gables, FL 33146 (United States); Hughes, David H. [Instituto Nacional de Astrofisica Optica y Electronica (INAOE), Aptdo. Postal 51 y 72000 Puebla (Mexico); Netterfield, Calvin B. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Olmi, Luca [INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 (Italy); Patanchon, Guillaume [Laboratoire APC, 10, rue Alice Domon et Leonie Duquet F-75205 Paris (France); and others

    2012-05-20

    The submillimeter opacity of dust in the diffuse interstellar medium (ISM) in the Galactic plane has been quantified using a pixel-by-pixel correlation of images of continuum emission with a proxy for column density. We used multi-wavelength continuum data: three Balloon-borne Large Aperture Submillimeter Telescope bands at 250, 350, and 500 {mu}m and one IRAS band at 100 {mu}m. The proxy is the near-infrared color excess, E(J - K{sub s}), obtained from the Two Micron All Sky Survey. Based on observations of stars, we show how well this color excess is correlated with the total hydrogen column density for regions of moderate extinction. The ratio of emission to column density, the emissivity, is then known from the correlations, as a function of frequency. The spectral distribution of this emissivity can be fit by a modified blackbody, whence the characteristic dust temperature T and the desired opacity {sigma}{sub e}(1200) at 1200 GHz or 250 {mu}m can be obtained. We have analyzed 14 regions near the Galactic plane toward the Vela molecular cloud, mostly selected to avoid regions of high column density (N{sub H} > 10{sup 22} cm{sup -2}) and small enough to ensure a uniform dust temperature. We find {sigma}{sub e}(1200) is typically (2-4) Multiplication-Sign 10{sup -25} cm{sup 2} H{sup -1} and thus about 2-4 times larger than the average value in the local high Galactic latitude diffuse atomic ISM. This is strong evidence for grain evolution. There is a range in total power per H nucleon absorbed (and re-radiated) by the dust, reflecting changes in the strength of the interstellar radiation field and/or the dust absorption opacity. These changes in emission opacity and power affect the equilibrium T, which is typically 15 K, colder than at high latitudes. Our analysis extends, to higher opacity and lower temperature, the trend of increasing {sigma}{sub e}(1200) with decreasing T that was found at high latitudes. The recognition of changes in the emission opacity

  19. Differential processing of binocular and monocular gloss cues in human visual cortex

    Science.gov (United States)

    Di Luca, Massimiliano; Ban, Hiroshi; Muryy, Alexander; Fleming, Roland W.

    2016-01-01

    The visual impression of an object's surface reflectance (“gloss”) relies on a range of visual cues, both monocular and binocular. Whereas previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here, we used human functional MRI (fMRI) to test for brain areas selectively involved in the processing of binocular cues. We manipulated stereoscopic information to create four conditions that differed in their disparity structure and in the impression of surface gloss that they evoked. We performed multivoxel pattern analysis to find areas whose fMRI responses allow classes of stimuli to be distinguished based on their depth structure vs. material appearance. We show that higher dorsal areas play a role in processing binocular gloss information, in addition to known ventral areas involved in material processing, with ventral area lateral occipital responding to both object shape and surface material properties. Moreover, we tested for similarities between the representation of gloss from binocular cues and monocular cues. Specifically, we tested for transfer in the decoding performance of an algorithm trained on glossy vs. matte objects defined by either binocular or by monocular cues. We found transfer effects from monocular to binocular cues in dorsal visual area V3B/kinetic occipital (KO), suggesting a shared representation of the two cues in this area. These results indicate the involvement of mid- to high-level visual circuitry in the estimation of surface material properties, with V3B/KO potentially playing a role in integrating monocular and binocular cues. PMID:26912596

  20. Differential processing of binocular and monocular gloss cues in human visual cortex.

    Science.gov (United States)

    Sun, Hua-Chun; Di Luca, Massimiliano; Ban, Hiroshi; Muryy, Alexander; Fleming, Roland W; Welchman, Andrew E

    2016-06-01

    The visual impression of an object's surface reflectance ("gloss") relies on a range of visual cues, both monocular and binocular. Whereas previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here, we used human functional MRI (fMRI) to test for brain areas selectively involved in the processing of binocular cues. We manipulated stereoscopic information to create four conditions that differed in their disparity structure and in the impression of surface gloss that they evoked. We performed multivoxel pattern analysis to find areas whose fMRI responses allow classes of stimuli to be distinguished based on their depth structure vs. material appearance. We show that higher dorsal areas play a role in processing binocular gloss information, in addition to known ventral areas involved in material processing, with ventral area lateral occipital responding to both object shape and surface material properties. Moreover, we tested for similarities between the representation of gloss from binocular cues and monocular cues. Specifically, we tested for transfer in the decoding performance of an algorithm trained on glossy vs. matte objects defined by either binocular or by monocular cues. We found transfer effects from monocular to binocular cues in dorsal visual area V3B/kinetic occipital (KO), suggesting a shared representation of the two cues in this area. These results indicate the involvement of mid- to high-level visual circuitry in the estimation of surface material properties, with V3B/KO potentially playing a role in integrating monocular and binocular cues. Copyright © 2016 the American Physiological Society.

  1. Visibility of monocular symbology in transparent head-mounted display applications

    Science.gov (United States)

    Winterbottom, M.; Patterson, R.; Pierce, B.; Gaska, J.; Hadley, S.

    2015-05-01

    With increased reliance on head-mounted displays (HMDs), such as the Joint Helmet Mounted Cueing System and F-35 Helmet Mounted Display System, research concerning visual performance has also increased in importance. Although monocular HMDs have been used successfully for many years, a number of authors have reported significant problems with their use. Certain problems have been attributed to binocular rivalry when differing imagery is presented to the two eyes. With binocular rivalry, the visibility of the images in the two eyes fluctuates, with one eye's view becoming dominant, and thus visible, while the other eye's view is suppressed, which alternates over time. Rivalry is almost certainly created when viewing an occluding monocular HMD. For semi-transparent monocular HMDs, however, much of the scene is binocularly fused, with additional imagery superimposed in one eye. Binocular fusion is thought to prevent rivalry. The present study was designed to investigate differences in visibility between monocularly and binocularly presented symbology at varying levels of contrast and while viewing simulated flight over terrain at various speeds. Visibility was estimated by measuring the presentation time required to identify a test probe (tumbling E) embedded within other static symbology. Results indicated that there were large individual differences, but that performance decreased with decreased test probe contrast under monocular viewing relative to binocular viewing conditions. Rivalry suppression may reduce visibility of semi-transparent monocular HMD imagery. However, factors, such as contrast sensitivity, masking, and conditions such as monofixation, will be important to examine in future research concerning visibility of HMD imagery.

  2. Eye movements in chameleons are not truly independent - evidence from simultaneous monocular tracking of two targets.

    Science.gov (United States)

    Katz, Hadas Ketter; Lustig, Avichai; Lev-Ari, Tidhar; Nov, Yuval; Rivlin, Ehud; Katzir, Gadi

    2015-07-01

    Chameleons perform large-amplitude eye movements that are frequently referred to as independent, or disconjugate. When prey (an insect) is detected, the chameleon's eyes converge to view it binocularly and 'lock' in their sockets so that subsequent visual tracking is by head movements. However, the extent of the eyes' independence is unclear. For example, can a chameleon visually track two small targets simultaneously and monocularly, i.e. one with each eye? This is of special interest because eye movements in ectotherms and birds are frequently independent, with optic nerves that are fully decussated and intertectal connections that are not as developed as in mammals. Here, we demonstrate that chameleons presented with two small targets moving in opposite directions can perform simultaneous, smooth, monocular, visual tracking. To our knowledge, this is the first demonstration of such a capacity. The fine patterns of the eye movements in monocular tracking were composed of alternating, longer, 'smooth' phases and abrupt 'step' events, similar to smooth pursuits and saccades. Monocular tracking differed significantly from binocular tracking with respect to both 'smooth' phases and 'step' events. We suggest that in chameleons, eye movements are not simply 'independent'. Rather, at the gross level, eye movements are (i) disconjugate during scanning, (ii) conjugate during binocular tracking and (iii) disconjugate, but coordinated, during monocular tracking. At the fine level, eye movements are disconjugate in all cases. These results support the view that in vertebrates, basic monocular control is under a higher level of regulation that dictates the eyes' level of coordination according to context. © 2015. Published by The Company of Biologists Ltd.

  3. Induction of Monocular Stereopsis by Altering Focus Distance: A Test of Ames's Hypothesis.

    Science.gov (United States)

    Vishwanath, Dhanraj

    2016-03-01

    Viewing a real three-dimensional scene or a stereoscopic image with both eyes generates a vivid phenomenal impression of depth known as stereopsis. Numerous reports have highlighted the fact that an impression of stereopsis can be induced in the absence of binocular disparity. A method claimed by Ames (1925) involved altering accommodative (focus) distance while monocularly viewing a picture. This claim was tested on naïve observers using a method inspired by the observations of Gogel and Ogle on the equidistance tendency. Consistent with Ames's claim, most observers reported that the focus manipulation induced an impression of stereopsis comparable to that obtained by monocular-aperture viewing.

  4. Elimination of aniseikonia in monocular aphakia with a contact lens-spectacle combination.

    Science.gov (United States)

    Schechter, R J

    1978-01-01

    Correction of monocular aphakia with contact lenses generally results in aniseikonia in the range of 7--9%; with correction by intraocular lenses, aniseikonia is approximately 2%. We present a new method of correcting aniseikonia in monocular aphakics using a contact lens-spectacle combination. A formula is derived wherein the contact lens is deliberately overcorrected; this overcorrection is then neutralized by the appropriate spectacle lens, to be worn over the contact lens. Calculated results with this system over a wide range of possible situations consistently results in an aniseikonia of 0.1%.

  5. END-TO-END DEPTH FROM MOTION WITH STABILIZED MONOCULAR VIDEOS

    Directory of Open Access Journals (Sweden)

    C. Pinard

    2017-08-01

    Full Text Available We propose a depth map inference system from monocular videos based on a novel dataset for navigation that mimics aerial footage from gimbal stabilized monocular camera in rigid scenes. Unlike most navigation datasets, the lack of rotation implies an easier structure from motion problem which can be leveraged for different kinds of tasks such as depth inference and obstacle avoidance. We also propose an architecture for end-to-end depth inference with a fully convolutional network. Results show that although tied to camera inner parameters, the problem is locally solvable and leads to good quality depth prediction.

  6. Development of monocular and binocular multi-focus 3D display systems using LEDs

    Science.gov (United States)

    Kim, Sung-Kyu; Kim, Dong-Wook; Son, Jung-Young; Kwon, Yong-Moo

    2008-04-01

    Multi-focus 3D display systems are developed and a possibility about satisfaction of eye accommodation is tested. The multi-focus means the ability of monocular depth cue to various depth levels. By achieving the multi-focus function, we developed 3D display systems for one eye and both eyes, which can satisfy accommodation to displayed virtual objects within defined depth. The monocular accommodation and the binocular convergence 3D effect of the system are tested and a proof of the satisfaction of the accommodation and experimental result of the binocular 3D fusion are given as results by using the proposed 3D display systems.

  7. Obtaining corneal tissue for keratoplasty.

    Science.gov (United States)

    Navarro Martínez-Cantullera, A; Calatayud Pinuaga, M

    2016-10-01

    Cornea transplant is the most common tissue transplant in the world. In Spain, tissue donation activities depend upon transplant coordinator activities and the well-known Spanish model for organ and tissue donation. Tissue donor detection system and tissue donor evaluation is performed mainly by transplant coordinators using the Spanish model on donation. The evaluation of a potential tissue donor from detection until recovery is based on an exhaustive review of the medical and social history, physical examination, family interview to determine will of the deceased, and a laboratory screening test. Corneal acceptance criteria for transplantation have a wider spectrum than other tissues, as donors with active malignancies and infections are accepted for kearatoplasty in most tissue banks. Corneal evaluation during the whole process is performed to ensure the safety of the donor and the recipient, as well as an effective transplant. Last step before processing, corneal recovery, must be performed under standard operating procedures and in a correct environment. Copyright © 2016 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  8. Nuclear reaction rates and opacity in massive star evolution calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bahena, D [Astronomical Institute of the Academy of Sciences, BocnI II 1401, 14131 Praha 4 (Czech Republic); Klapp, J [Instituto Nacional de Investigaciones Nucleares, Km. 36.5 Carr. Mexico-Toluca, 52750 Edo. de Mexico (Mexico); Dehnen, H, E-mail: jaime.klapp@inin.gob.m [Universitaet Konstanz, Fachbereich Physik, Fach M568, D-78457 Konstanz (Germany)

    2010-07-01

    Nuclear reaction rates and opacity are important parameters in stellar evolution. The input physics in a stellar evolution code determines the main theoretical characteristics of the stellar structure, evolution and nucleosynthesis of a star. For different input physics, in this work we calculate stellar evolution models of very massive first stars during the hydrogen and helium burning phases. We have considered 100 and 200M{sub s}un galactic and pregalactic stars with metallicity Z = 10{sup -6} and 10{sup 9}, respectively. The results show important differences from old to new formulations for the opacity and nuclear reaction rates, in particular the evolutionary tracks are significantly affected, that indicates the importance of using up to date and reliable input physics. The triple alpha reaction activates sooner for pregalactic than for galactic stars.

  9. Towards a new model of OPAC. From information to knowledge.

    Directory of Open Access Journals (Sweden)

    Antonella Iacono

    2013-07-01

    Full Text Available Il contributo analizza l’evoluzione dei cataloghi elettronici delle biblioteche alla luce delle nuove tecnologie del Web semantico e dei linked data. La trattazione è suddivisa in due parti distinte. In questa prima parte muovendo da un’analisi critica del modello funzionale degli ‘OPAC di nuova generazione’ e discovery tools si propone la necessità di una revisione del paradigma corrente di sviluppo che accogliendo le teorie dell’information behavior possa fondarsi sull'utente, sui suoi bisogni informativi, i suoi comportamenti e sull'analisi delle componenti che entrano in gioco nel processo di ricerca dell'informazione.Nella seconda parte, di prossima pubblicazione si è esplorerà la possibilità che i linked data possano essere la tecnologia più appropriata per la costruzione di nuovi OPAC basati sulla produzione di conoscenza all’interno del processo informativo. 

  10. Model-independent constraints on the cosmic opacity

    Energy Technology Data Exchange (ETDEWEB)

    Holanda, R.F.L. [Departamento de Física, Universidade Estadual da Paraíba, 58429-500, Campina Grande - PB (Brazil); Carvalho, J.C.; Alcaniz, J.S., E-mail: holanda@uepb.edu.br, E-mail: carvalho@dfte.ufrn.br, E-mail: alcaniz@on.br [Departamento de Astronomia, Observatório Nacional, 20921-400, Rio de Janeiro - RJ (Brazil)

    2013-04-01

    We use current measurements of the expansion rate H(z) and cosmic background radiation bounds on the spatial curvature of the Universe to impose cosmological model-independent constraints on cosmic opacity. To perform our analyses, we compare opacity-free distance modulus from H(z) data with those from two type Ia supernovae compilations, namely, the Union2.1 plus the most distant spectroscopically confirmed SNe Ia (SCP-0401 at z = 1.713) and two Sloan Digital Sky Survey (SDSS) subsamples. We find that a completely transparent universe is in full agreement with the Union 2.1 + SNe Ia SCP-0401 sample. For the SDSS compilations, such universe is compatible with observations at < 1.5σ level regardless the SNe Ia light-curve fitting used.

  11. Design of Initial Opacity Platform at the National Ignition Facility

    Science.gov (United States)

    Heeter, R. F.; Ahmed, M. F.; Ayers, S. L.; Emig, J. A.; Iglesias, C. A.; Liedahl, D. A.; Schneider, M. B.; Wilson, B. G.; Huffman, E. J.; King, J. A.; Opachich, Y. P.; Ross, P. W.; Bailey, J. E.; Rochau, G. A.; Craxton, R. S.; Garcia, E. M.; McKenty, P. W.; Zhang, R.; Cardenas, T.; Devolder, B. G.; Dodd, E. S.; Kline, J. L.; Sherrill, M. E.; Perry, T. S.

    2016-10-01

    The absorption and re-emission of x-rays by partly stripped ions plays a critical role in stars and in many laboratory plasmas. A NIF Opacity Platform has been designed to resolve a persistent disagreement between theory and experiments on the Sandia Z facility, studying iron in conditions closely related to the solar radiation-convection transition boundary. A laser heated hohlraum ``oven'' will produce iron plasmas at temperatures >150 eV and electron densities >=7x1021/cm3, and be probed with continuum X-rays from a capsule implosion backlighter source. The resulting X-ray transmission spectra will be recorded on a specially designed Opacity Spectrometer. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  12. Equation of state and opacities for warm dense matter

    Directory of Open Access Journals (Sweden)

    Cotelo Manuel

    2013-11-01

    Full Text Available This work presents recent developments in the calculation of opacity and equation of state tables suitable for including in the radiation hydrodynamic code ARWEN [1] to study processes like ICF or X-ray secondary sources. For these calculations we use the code bigbart to compute opacities in LTE conditions, with self-consistent data generated with the Flexible Atomic Code (FAC [2]. Non-LTE effects are approximately taken into account by means of the new RADIOM model developed in [3], which makes use of existing LTE data tables. We use the screened-hydrogenic model [4] to derive the Equation of State (EOS using the population and energy of each level.

  13. Skewed gas flow technology offers antidote to opacity derates

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, M. [ATCO Power AB (Canada). Battle River Generating Station

    2001-06-01

    Deratings due to opacity problems at the Battle River Generating Station in Alberta, Canada led ATCO Power to evaluate and install skewed gas flow technology (SGFT) in one-half of the Unit 5 twin-casing electrostatic precipitator during the August 2000 outage. Preliminary operating results show that the modified casing produces opacity readings at the outlet 40% lower than those seen at the outlet of the unmodified casing. The dust loading tests indicate a 27.5% improvement in collector efficiency. This article includes a technical review and evaluation of Battle River's SGFT installation, as well as the rationale used to provide the initial economic justification. 3 figs., 1 tab., 1 photo.

  14. Opacity calculations for Non-Local-Thermodynamic-Equilibrium plasmas

    Institute of Scientific and Technical Information of China (English)

    PANG Jin-qiao; WU Ze-qing; YAN Jun; HAN Guo-xing

    2004-01-01

    In this paper, we presented a method to calculate the spectral-resolved opacity for Non-Local-Thermodynamic-Equilibrium (non-LTE) plasmas. By solving the rate equations, we get the population. In the rate equations, configuration-averaged rate coefficients are used and the cross sections are calculated based on the first-perturbation theory. Using the detailed configuration accounting with the term structures treated by the unresolved transition array model, we calculated the spectral-resolved opacity of Al plasmas. The results are compared with those of other theoretical models. From the comparison, we can see that the present results fit well with other models for low-Z plasmas. For high-Z plasmas, we will give detailed discussion in the future.

  15. FTS Measurements of Submillimeter-Wave Atmospheric Opacity at Pampa la Bola

    Science.gov (United States)

    Matsuo, Hiroshi; Sakamoto, Akihiro; Matsushita, Satoki

    1998-06-01

    The first measurements of submillimeter-wave atmospheric opacity spectra at the Pampa la Bola site (Northern Chile, Atacama, 4800 m altitude) have been performed during the winter season using a Fourier transform spectrometer (FTS). Atmospheric emission spectra, as a function of airmass, were measured under various weather conditions. Atmospheric opacity was evaluated from sky temperature at the zenith as well as from tipping measurements, which are independent measures but give consistent results. Correlation diagrams between 220 GHz and 345 GHz, 410 GHz, 492 GHz, 675 GHz, 691 GHz, 809 GHz, 875 GHz are shown. Correlations between millimeter-wave and submillimeter-wave opacities get worse when 220 GHz opacity is larger than 0.1. Deviations from the opacity correlation at each frequency show good correlations themselves, but have different relative variations at each frequency. This indicates that atmospheric transparency cannot be characterized only by millimeter-wave opacity, but requires simultaneous opacity measurements at millimeter and submillimeter-wavelengths.

  16. A native-like corneal construct using donor corneal stroma for tissue engineering.

    Directory of Open Access Journals (Sweden)

    Jing Lin

    Full Text Available Tissue engineering holds great promise for corneal transplantation to treat blinding diseases. This study was to explore the use of natural corneal stroma as an optimal substrate to construct a native like corneal equivalent. Human corneal epithelium was cultivated from donor limbal explants on corneal stromal discs prepared by FDA approved Horizon Epikeratome system. The morphology, phenotype, regenerative capacity and transplantation potential were evaluated by hematoxylin eosin and immunofluorescent staining, a wound healing model, and the xeno-transplantation of the corneal constructs to nude mice. An optically transparent and stratified epithelium was rapidly generated on donor corneal stromal substrate and displayed native-like morphology and structure. The cells were polygonal in the basal layer and became flattened in superficial layers. The epithelium displayed a phenotype similar to human corneal epithelium in vivo. The differentiation markers, keratin 3, involucrin and connexin 43, were expressed in full or superficial layers. Interestingly, certain basal cells were immunopositive to antibodies against limbal stem/progenitor cell markers ABCG2 and p63, which are usually negative in corneal epithelium in vivo. It suggests that this bioengineered corneal epithelium shared some characteristics of human limbal epithelium in vivo. This engineered epithelium was able to regenerate in 4 days following from a 4mm-diameter wound created by a filter paper soaked with 1 N NaOH. This corneal construct survived well after xeno-transplantation to the back of a nude mouse. The transplanted epithelium remained multilayer and became thicker with a phenotype similar to human corneal epithelium. Our findings demonstrate that natural corneal stroma is an optimal substrate for tissue bioengineering, and a native-like corneal construct has been created with epithelium containing limbal stem cells. This construct may have great potential for clinical use in

  17. Controlled opacity in a class of nonlinear dielectric media

    Science.gov (United States)

    Bittencourt, E.; Camargo, G. H. S.; De Lorenci, V. A.; Klippert, R.

    2017-03-01

    Motivated by new technologies for designing and tailoring metamaterials, we seek properties for certain classes of nonlinear optical materials that allow room for a reversibly controlled opacity-to-transparency phase transition through the application of external electromagnetic fields. We examine some mathematically simple models for the dielectric parameters of the medium and compute the relevant geometric quantities that describe the speed and polarization of light rays.

  18. The EOSTA model for opacities and EOS calculations

    Science.gov (United States)

    Barshalom, Avraham; Oreg, Joseph

    2007-11-01

    The EOSTA model developed recently combines the STA and INFERNO models to calculate opacities and EOS on the same footing. The quantum treatment of the plasma continuum and the inclusion of the resulted shape resonances yield a smooth behavior of the EOS and opacity global quantities vs density and temperature. We will describe the combined model and focus on its latest improvements. In particular we have extended the use of the special representation of the relativistic virial theorem to obtain an exact differential equation for the free energy. This equation, combined with a boundary condition at the zero pressure point, serves to advance the LDA EOS results significantly. The method focuses on applicability to high temperature and high density plasmas, warm dens matter etc. but applies at low temperatures as well treating fluids and even solids. Excellent agreement is obtained with experiments covering a wide range of density and temperature. The code is now used to create EOS and opacity databases for the use of hydro-dynamical simulations.

  19. Formation of Jupiter using opacities based on detailed grain physics

    CERN Document Server

    Movshovitz, Naor; Podolak, Morris; Lissauer, Jack J

    2010-01-01

    Numerical simulations, based on the core-nucleated accretion model, are presented for the formation of Jupiter at 5.2 AU in 3 primordial disks with three different assumed values of the surface density of solid particles. The grain opacities in the envelope of the protoplanet are computed using a detailed model that includes settling and coagulation of grains and that incorporates a recalculation of the grain size distribution at each point in time and space. We generally find lower opacities than the 2% of interstellar values used in previous calculations [Hubickyj, O., Bodenheimer, P., Lissauer, J. J., 2005. Icarus 179, 415--431; Lissauer, J. J., Hubickyj, O., D'Angelo, G., Bodenheimer, P., 2009. Icarus 199, 338-350]. These lower opacities result in more rapid heat loss from and more rapid contraction of the protoplanetary envelope. For a given surface density of solids, the new calculations result in a substantial speedup in formation time as compared with those previous calculations. Formation times are c...

  20. Lens opacities after repeated exposure to ultraviolet radiation.

    Science.gov (United States)

    Michael, R; Löfgren, S; Söderberg, P G

    1999-12-01

    To investigate the effect of the interval between two, near-threshold exposures to ultraviolet radiation (UVR) on cataract development. One eye of Sprague-Dawley rats was exposed twice to 4 kJ/m2 narrow band UVR (lambdaMAX=300 nm) for 15 min each. The interval between exposures was 0, 6, 24 or 48 h. One week after the first exposure both lenses were removed for photography and measurement of the intensity of forward light scattering to quantify lens opacities. All exposed lenses developed cataract. Forward light scattering was the same after double exposure with no interval or a 6 h interval. Forward light scattering after a 24 or 48 h interval was nearly twofold greater than that following no interval or a 6 h interval. The exposed lenses in all groups had mild anterior surface opacities and intense equatorial opacities as judged with a stereomicroscope. Two, near-threshold UVR exposures at 0 or a 6 h interval produce the same degree of lens opacification. When the second exposure follows 24 or 48 h after the first, lenticular damage increases. Repair processes between 24 and 48 h after exposure appear to be sensitive to UVR, and an additional exposure during this time may aggravate cataract development.

  1. Enforcement of opacity security properties for ship information system

    Directory of Open Access Journals (Sweden)

    Bowen Xing

    2016-09-01

    Full Text Available In this paper, we consider the cybersecurity issue of ship information system (SIS from a new perspective which is called opacity. For a SIS, its confidential information (named as “secret” may be leaked through the working behaviors of each Distributed Control Unit (DCU from an outside observer called an “intruder” which is able to determine ship's mission state by detecting the source of each data flow from the corresponding DCUs in SIS. Therefore we proposed a dual layer mechanism to enforce opacity by activating non-essential DCU during secret mission. This mechanism is calculated by two types of insertion functions: Safety-assured insertion function (fIS and Admissibility-assured insertion function (fIA. Due to different objectives, fIS is designed to confuse intruder by constructing a non-secret behaviors from a unsafe one, and the division of fIA is to polish the modified output behaviors back to normal. We define the property of “I2–Enforceability” that dual layer insertion functions has the ability to enforce opacity. By a given mission map of SIS and the marked secret missions, we propose an algorithm to select fIS and compute its matchable fIA and then the DCUs which should be activated to release non-essential data flow in each step is calculable.

  2. Corneal tomography and biomechanics in primary pterygium.

    Science.gov (United States)

    Vanathi, M; Goel, Sahil; Ganger, Anita; Agarwal, Tushar; Dada, T; Khokhar, Sudarshan

    2017-05-13

    To study the Scheimpflug's imaging and corneal biomechanics in primary pterygium. A prospective observational study of 55 patients with unilateral primary nasal pterygium was done. The normal fellow eyes of patients with pterygium were taken as controls. Clinical parameters noted included visual acuity, values of corneal curvature by doing Scheimpflug imaging, wavefront aberrations in terms of higher and lower-order aberrations and corneal hysteresis (CH) as well as corneal resistance factor (CRF) values by using ocular response analyzer. Of the total 55 patients, mean age was 43.0 + 11.4 years (range: 20-72 years). Mean LogMar uncorrected visual acuity in pterygium eyes and control eyes was 0.21 + 0.20 and 0.12 + 0.15, respectively (p = 0.016). On Scheimpflug imaging the mean anterior corneal curvature values (Ka1/Ka2 D) were 41.09 + 3.38/44.33 + 2.29 in pterygium eyes, 43.13 + 1.79/43.98 + 2.17 in control eyes (p  0.05). Analysis of corneal aberrations showed significantly higher corneal wavefront aberrations in pterygium eyes. Highest correlation of corneal astigmatism was noted with corneal area encroached by pterygium (ρ = 0.540 for LOA and 0.553 for HOA) and distance from pupillary center (ρ = 0.531 for LOA and 0.564 for HOA). Corneal biomechanical parameters including CH and CRF were found to be lower in the pterygium eyes, though not statistically significant (p value 0.60 and 0.59, respectively). Pterygium leads to deterioration of visual performance not only by causing refractive and topographic changes but also by causing a significant increase in corneal wavefront aberrations.

  3. Effective Tree Scattering and Opacity at L-Band

    Science.gov (United States)

    Kurum, Mehmet; O'Neill, Peggy E.; Lang, Roger H.; Joseph, Alicia T.; Cosh, Michael H.; Jackson, Thomas J.

    2011-01-01

    This paper investigates vegetation effects at L-band by using a first-order radiative transfer (RT) model and truck-based microwave measurements over natural conifer stands to assess the applicability of the tau-omega) model over trees. The tau-omega model is a zero-order RT solution that accounts for vegetation effects with effective vegetation parameters (vegetation opacity and single-scattering albedo), which represent the canopy as a whole. This approach inherently ignores multiple-scattering effects and, therefore, has a limited validity depending on the level of scattering within the canopy. The fact that the scattering from large forest components such as branches and trunks is significant at L-band requires that zero-order vegetation parameters be evaluated (compared) along with their theoretical definitions to provide a better understanding of these parameters in the retrieval algorithms as applied to trees. This paper compares the effective vegetation opacities, computed from multi-angular pine tree brightness temperature data, against the results of two independent approaches that provide theoretical and measured optical depths. These two techniques are based on forward scattering theory and radar corner reflector measurements, respectively. The results indicate that the effective vegetation opacity values are smaller than but of similar magnitude to both radar and theoretical estimates. The effective opacity of the zero-order model is thus set equal to the theoretical opacity and an explicit expression for the effective albedo is then obtained from the zero- and first- order RT model comparison. The resultant albedo is found to have a similar magnitude as the effective albedo value obtained from brightness temperature measurements. However, it is less than half of that estimated using the theoretical calculations (0.5 - 0.6 for tree canopies at L-band). This lower observed albedo balances the scattering darkening effect of the large theoretical albedo

  4. Stochastically optimized monocular vision-based navigation and guidance

    Science.gov (United States)

    Watanabe, Yoko

    The objective of this thesis is to design a relative navigation and guidance law for unmanned aerial vehicles, or UAVs, for vision-based control applications. The autonomous operation of UAVs has progressively developed in recent years. In particular, vision-based navigation, guidance and control has been one of the most focused on research topics for the automation of UAVs. This is because in nature, birds and insects use vision as the exclusive sensor for object detection and navigation. Furthermore, it is efficient to use a vision sensor since it is compact, light-weight and low cost. Therefore, this thesis studies the monocular vision-based navigation and guidance of UAVs. Since 2-D vision-based measurements are nonlinear with respect to the 3-D relative states, an extended Kalman filter (EKF) is applied in the navigation system design. The EKF-based navigation system is integrated with a real-time image processing algorithm and is tested in simulations and flight tests. The first closed-loop vision-based formation flight between two UAVs has been achieved, and the results are shown in this thesis to verify the estimation performance of the EKF. In addition, vision-based 3-D terrain recovery was performed in simulations to present a navigation design which has the capability of estimating states of multiple objects. In this problem, the statistical z-test is applied to solve the correspondence problem of relating measurements and estimation states. As a practical example of vision-based control applications for UAVs, a vision-based obstacle avoidance problem is specially addressed in this thesis. A navigation and guidance system is designed for a UAV to achieve a mission of waypoint tracking while avoiding unforeseen stationary obstacles by using vision information. An EKF is applied to estimate each obstacles' position from the vision-based information. A collision criteria is established by using a collision-cone approach and a time-to-go criterion. A minimum

  5. Corneal laceration caused by river crab

    Directory of Open Access Journals (Sweden)

    Vinuthinee N

    2015-01-01

    Full Text Available Naidu Vinuthinee,1,2 Anuar Azreen-Redzal,1 Jaafar Juanarita,1 Embong Zunaina2 1Department of Ophthalmology, Hospital Sultanah Bahiyah, Alor Setar, 2Department of Ophthalmology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia Abstract: A 5-year-old boy presented with right eye pain associated with tearing and photophobia of 1-day duration. He gave a history of playing with a river crab when suddenly the crab clamped his fingers. He attempted to fling the crab off, but the crab flew and hit his right eye. Ocular examination revealed a right eye corneal ulcer with clumps of fibrin located beneath the corneal ulcer and 1.6 mm level of hypopyon. At presentation, the Seidel test was negative, with a deep anterior chamber. Culture from the corneal scrapping specimen grew Citrobacter diversus and Proteus vulgaris, and the boy was treated with topical gentamicin and ceftazidime eyedrops. Fibrin clumps beneath the corneal ulcer subsequently dislodged, and revealed a full-thickness corneal laceration wound with a positive Seidel test and shallow anterior chamber. The patient underwent emergency corneal toileting and suturing. Postoperatively, he was treated with oral ciprofloxacin 250 mg 12-hourly for 1 week, topical gentamicin, ceftazidime, and dexamethasone eyedrops for 4 weeks. Right eye vision improved to 6/9 and 6/6 with pinhole at the 2-week follow-up following corneal suture removal. Keywords: corneal ulcer, pediatric trauma, ocular injury

  6. Corneal staining after treatment with topical tetracycline

    NARCIS (Netherlands)

    R. Lapid-Gortzak; C.P. Nieuwendaal; A.R. Slomovic; L. Spanjaard

    2006-01-01

    Purpose: The purpose of this paper is to report a case of corneal staining after treatment with topical tetracycline. Methods: A patient with crystalline keratopathy caused by Streptococcus viridans after corneal transplantation was treated topically with tetracycline eye drops, based on results of

  7. Corneal cellular proliferation and wound healing

    OpenAIRE

    Gan, Lisha

    2000-01-01

    Background. Cellular proliferation plays an important role in both physiological and pathological processes. Epithelial hyperplasia in the epithelium, excessive scar formation in retrocorneal membrane formation and neovascularization are examples of excessive proliferation of cornea cells. Lack of proliferative ability causes corneal degeneration. The degree of proliferative and metabolic activity will directly influence corneal transparency and very evidently refractive res...

  8. Corynebacterium macginleyi isolated from a corneal ulcer

    Directory of Open Access Journals (Sweden)

    Kathryn Ruoff

    2010-02-01

    Full Text Available We report the isolation of Corynebacterium macginleyi from the corneal ulcer culture of a patient, later enrolled in the Steroids for Corneal Ulcer Trial (SCUT. To our knowledge this is the first published report from North America of the recovery of C. macginleyi from a serious ocular infection.

  9. Monocular zones in stereoscopic scenes: A useful source of information for human binocular vision?

    Science.gov (United States)

    Harris, Julie M.

    2010-02-01

    When an object is closer to an observer than the background, the small differences between right and left eye views are interpreted by the human brain as depth. This basic ability of the human visual system, called stereopsis, lies at the core of all binocular three-dimensional (3-D) perception and related technological display development. To achieve stereopsis, it is traditionally assumed that corresponding locations in the right and left eye's views must first be matched, then the relative differences between right and left eye locations are used to calculate depth. But this is not the whole story. At every object-background boundary, there are regions of the background that only one eye can see because, in the other eye's view, the foreground object occludes that region of background. Such monocular zones do not have a corresponding match in the other eye's view and can thus cause problems for depth extraction algorithms. In this paper I will discuss evidence, from our knowledge of human visual perception, illustrating that monocular zones do not pose problems for our human visual systems, rather, our visual systems can extract depth from such zones. I review the relevant human perception literature in this area, and show some recent data aimed at quantifying the perception of depth from monocular zones. The paper finishes with a discussion of the potential importance of considering monocular zones, for stereo display technology and depth compression algorithms.

  10. Perception of Acceleration in Motion-In-Depth With Only Monocular and Binocular Information

    Directory of Open Access Journals (Sweden)

    Santiago Estaún

    2003-01-01

    Full Text Available Percepción de la aceleración en el movimiento en profundidad con información monocular y con información monocular y binocular. En muchas ocasiones es necesario adecuar nuestras acciones a objetos que cambian su aceleración. Sin embargo, no se ha encontrado evidencia de una percepción directa de la aceleración. En su lugar, parece ser que somos capaces de detectar cambios de velocidad en el movimiento 2-D dentro de una ventana temporal. Además, resultados recientes sugieren que el movimiento en profundidad se detecta a través de cambios de posición. Por lo tanto, para detectar aceleración en profundidad sería necesario que el sistema visual lleve a cabo algun tipo de cómputo de segundo orden. En dos experimentos, mostramos que los observadores no perciben la aceleración en trayectorias de aproximación, al menos en los rangos que utilizados [600- 800 ms] dando como resultado una sobreestimación del tiempo de llegada. Independientemente de la condición de visibilidad (sólo monocular o monocular más binocular, la respuesta se ajusta a una estrategia de velocidad constante. No obstante, la sobreestimación se reduce cuando la información binocular está disponible.

  11. Depth of Monocular Elements in a Binocular Scene: The Conditions for da Vinci Stereopsis

    Science.gov (United States)

    Cook, Michael; Gillam, Barbara

    2004-01-01

    Quantitative depth based on binocular resolution of visibility constraints is demonstrated in a novel stereogram representing an object, visible to 1 eye only, and seen through an aperture or camouflaged against a background. The monocular region in the display is attached to the binocular region, so that the stereogram represents an object which…

  12. Binocular and Monocular Depth Cues in Online Feedback Control of 3-D Pointing Movement

    Science.gov (United States)

    Hu, Bo; Knill, David C.

    2012-01-01

    Previous work has shown that humans continuously use visual feedback of the hand to control goal-directed movements online. In most studies, visual error signals were predominantly in the image plane and thus were available in an observer’s retinal image. We investigate how humans use visual feedback about finger depth provided by binocular and monocular depth cues to control pointing movements. When binocularly viewing a scene in which the hand movement was made in free space, subjects were about 60 ms slower in responding to perturbations in depth than in the image plane. When monocularly viewing a scene designed to maximize the available monocular cues to finger depth (motion, changing size and cast shadows), subjects showed no response to perturbations in depth. Thus, binocular cues from the finger are critical to effective online control of hand movements in depth. An optimal feedback controller that takes into account of the low peripheral stereoacuity and inherent ambiguity in cast shadows can explain the difference in response time in the binocular conditions and lack of response in monocular conditions. PMID:21724567

  13. Depth of Monocular Elements in a Binocular Scene: The Conditions for da Vinci Stereopsis

    Science.gov (United States)

    Cook, Michael; Gillam, Barbara

    2004-01-01

    Quantitative depth based on binocular resolution of visibility constraints is demonstrated in a novel stereogram representing an object, visible to 1 eye only, and seen through an aperture or camouflaged against a background. The monocular region in the display is attached to the binocular region, so that the stereogram represents an object which…

  14. LASIK monocular en pacientes adultos con ambliopía por anisometropía

    Directory of Open Access Journals (Sweden)

    Alejandro Tamez-Peña

    2017-09-01

    Conclusiones: La cirugía refractiva monocular en pacientes con ambliopía por anisometropía es una opción terapéutica segura y efectiva que ofrece resultados visuales satisfactorios, preservando o incluso mejorando la AVMC preoperatoria.

  15. Binocular and monocular depth cues in online feedback control of 3D pointing movement.

    Science.gov (United States)

    Hu, Bo; Knill, David C

    2011-06-30

    Previous work has shown that humans continuously use visual feedback of the hand to control goal-directed movements online. In most studies, visual error signals were predominantly in the image plane and, thus, were available in an observer's retinal image. We investigate how humans use visual feedback about finger depth provided by binocular and monocular depth cues to control pointing movements. When binocularly viewing a scene in which the hand movement was made in free space, subjects were about 60 ms slower in responding to perturbations in depth than in the image plane. When monocularly viewing a scene designed to maximize the available monocular cues to finger depth (motion, changing size, and cast shadows), subjects showed no response to perturbations in depth. Thus, binocular cues from the finger are critical to effective online control of hand movements in depth. An optimal feedback controller that takes into account the low peripheral stereoacuity and inherent ambiguity in cast shadows can explain the difference in response time in the binocular conditions and lack of response in monocular conditions.

  16. Depth scaling in phantom and monocular gap stereograms using absolute distance information.

    Science.gov (United States)

    Kuroki, Daiichiro; Nakamizo, Sachio

    2006-11-01

    The present study aimed to investigate whether the visual system scales apparent depth from binocularly unmatched features by using absolute distance information. In Experiment 1 we examined the effect of convergence on perceived depth in phantom stereograms [Gillam, B., & Nakayama, K. (1999). Quantitative depth for a phantom surface can be based on cyclopean occlusion cues alone. Vision Research, 39, 109-112.], monocular gap stereograms [Pianta, M. J., & Gillam, B. J. (2003a). Monocular gap stereopsis: manipulation of the outer edge disparity and the shape of the gap. Vision Research, 43, 1937-1950.] and random dot stereograms. In Experiments 2 and 3 we examined the effective range of viewing distances for scaling the apparent depths in these stereograms. The results showed that: (a) the magnitudes of perceived depths increased in all stereograms as the estimate of the viewing distance increased while keeping proximal and/or distal sizes of the stimuli constant, and (b) the effective range of viewing distances was significantly shorter in monocular gap stereograms. The first result indicates that the visual system scales apparent depth from unmatched features as well as that from horizontal disparity, while the second suggests that, at far distances, the strength of the depth signal from an unmatched feature in monocular gap stereograms is relatively weaker than that from horizontal disparity.

  17. Dorsally located corneal dermoid in a cat

    Directory of Open Access Journals (Sweden)

    Alexander J LoPinto

    2016-04-01

    Full Text Available Case summary A 2-month-old, male kitten was presented for evaluation of unilateral blepharospasm and epiphora involving the right eye. Ocular examination revealed conjunctivitis, a superficial corneal ulcer, reflex anterior uveitis and a haired mass within the dorsal cornea of the right eye. The mass was subsequently removed surgically via a lamellar keratectomy. Histologic evaluation of the mass via light microscopy revealed it to be comprised of normal-haired skin with mild inflammation. One week after surgical removal and medical management of the corneal ulcer, all ocular clinical signs had resolved with minimal corneal scarring. On re-examination 6 months following surgical excision of the mass, the kitten was noted to be comfortable with no significant corneal scarring. Relevance and novel information To our knowledge, this is the first case report of a dorsally located corneal dermoid in a cat.

  18. Corneal Topographical Changes Flollowing Strabismus Surgery

    Institute of Scientific and Technical Information of China (English)

    MaiGH; WangZ

    1999-01-01

    Purpose:To study corneal topographical changes after strabismus surgery.Methods:Computer-aided corneal topography was used in 43 strabismus patients(45 eyes)one or two days prior to and six or seven ays after strabismus surgery.The spherical and cylindrical equivalents were calculated based on the simulated keratometry.Results:After the surgery,only the changes at 3mm in the inferior quadrant were statistically significant.The changes at 3mm in the rest quadrants and the changes at 7mm were no significant.Significant changes in spherical equivalent were found post-operatively.neither the horizontal nor the verical meridional equivalent showed significant changes after surgery.Conclusions:The results of corneal topographical changes following strabismus surgery in our preliminary study indicated the little effect of strabismus surgery on corneal curvature and corneal astigmatism.

  19. Corneal neovascularization and contemporary antiangiogenic therapeutics.

    Science.gov (United States)

    Hsu, Chih-Chien; Chang, Hua-Ming; Lin, Tai-Chi; Hung, Kuo-Hsuan; Chien, Ke-Hung; Chen, Szu-Yu; Chen, San-Ni; Chen, Yan-Ting

    2015-06-01

    Corneal neovascularization (NV), the excessive ingrowth of blood vessels from conjunctiva into the cornea, is a common sequela of disease insult that can lead to visual impairment. Clinically, topical steroid, argon laser photocoagulation, and subconjunctival injection of bevacizumab have been used to treat corneal NV. Sometimes, the therapies are ineffective, especially when the vessels are large. Large vessels are difficult to occlude and easily recanalized. Scientists and physicians are now dedicated to overcoming this problem. In this article, we briefly introduce the pathogenesis of corneal NV, and then highlight the existing animal models used in corneal NV research-the alkali-induced model and the suture-induced model. Most of all, we review the potential therapeutic targets (i.e., vascular endothelial growth factor and platelet-derived growth factor) and their corresponding inhibitors, as well as the immunosuppressants that have been discovered in recent years by corneal NV studies.

  20. Plasma polymer-coated contact lenses for the culture and transfer of corneal epithelial cells in the treatment of limbal stem cell deficiency.

    Science.gov (United States)

    Brown, Karl David; Low, Suet; Mariappan, Indumathi; Abberton, Keren Maree; Short, Robert; Zhang, Hong; Maddileti, Savitri; Sangwan, Virender; Steele, David; Daniell, Mark

    2014-02-01

    Extensive damage to the limbal region of the cornea leads to a severe form of corneal blindness termed as limbal stem cell deficiency (LSCD). Whereas most cases of corneal opacity can be treated with full thickness corneal transplants, LSCD requires stem cell transplantation for successful ocular surface reconstruction. Current treatments for LSCD using limbal stem cell transplantation involve the use of murine NIH 3T3 cells and human amniotic membranes as culture substrates, which pose the threat of transmission of animal-derived pathogens and donor tissue-derived cryptic infections. In this study, we aimed to produce surface modified therapeutic contact lenses for the culture and delivery of corneal epithelial cells for the treatment of LSCD. This approach avoids the possibility of suture-related complications and is completely synthetic. We used plasma polymerization to deposit acid functional groups onto the lenses at various concentrations. Each surface was tested for its suitability to promote corneal epithelial cell adhesion, proliferation, retention of stem cells, and differentiation and found that acid-based chemistries promoted better cell adhesion and proliferation. We also found that the lenses coated with a higher percentage of acid functional groups resulted in a higher number of cells transferred onto the corneal wound bed in rabbit models of LSCD. Immunohistochemistry of the recipient cornea confirmed the presence of autologous, transplanted 5-bromo-2'-deoxyuridine (BrdU)-labeled cells. Hematoxylin staining has also revealed the presence of a stratified epithelium at 26 days post-transplantation. This study provides the first evidence for in vivo transfer and survival of cells transplanted from a contact lens to the wounded corneal surface. It also proposes the possibility of using plasma polymer-coated contact lenses with high acid functional groups as substrates for the culture and transfer of limbal cells in the treatment of LSCD.

  1. Corneal Regeneration by Deep Anterior Lamellar Keratoplasty (DALK Using Decellularized Corneal Matrix.

    Directory of Open Access Journals (Sweden)

    Yoshihide Hashimoto

    Full Text Available The purpose of this study is to demonstrate the feasibility of DALK using a decellularized corneal matrix obtained by HHP methodology. Porcine corneas were hydrostatically pressurized at 980 MPa at 10°C for 10 minutes to destroy the cells, followed by washing with EGM-2 medium to remove the cell debris. The HHP-treated corneas were stained with H-E to assess the efficacy of decellularization. The decellularized corneal matrix of 300 μm thickness and 6.0 mm diameter was transplanted onto a 6.0 mm diameter keratectomy wound. The time course of regeneration on the decellularized corneal matrix was evaluated by haze grading score, fluorescein staining, and immunohistochemistry. H-E staining revealed that no cell nuclei were observed in the decellularized corneal matrix. The decellularized corneal matrices were opaque immediately after transplantation, but became completely transparent after 4 months. Fluorescein staining revealed that initial migration of epithelial cells over the grafts was slow, taking 3 months to completely cover the implant. Histological sections revealed that the implanted decellularized corneal matrix was completely integrated with the receptive rabbit cornea, and keratocytes infiltrated into the decellularized corneal matrix 6 months after transplantation. No inflammatory cells such as macrophages, or neovascularization, were observed during the implantation period. The decellularized corneal matrix improved corneal transparency, and remodelled the graft after being transplanted, demonstrating that the matrix obtained by HHP was a useful graft for corneal tissue regeneration.

  2. Radiation attenuation and opacity in smoke and water sprays

    Science.gov (United States)

    Parent, Gilles; Boulet, Pascal; Morlon, Romain; Blanchard, Elizabeth

    2017-08-01

    Radiation attenuation through sprays, smoke and mixings of both media was studied in the infrared and in the visible range, by conducting real scale experiments in a corridor. The effect of water injection by a water mist nozzle and a sprinkler device was investigated. Radiation attenuation in the infrared range and opacity in the visible range were measured, by using a FTIR spectrometer and a dedicated opacimetry device especially designed for the present application. Experiments were done using either a blackbody source for attenuation characterization, or a heptane pool fire aimed at producing smoke for opacity measurements. For tests with smoke, the difficulties raised by the harsh environment involving a hot mixing of gas plus soot and vapor carrying water droplets were circumvented with an original device involving an optical fiber network. Mean infrared transmission was found equal to 12% for the water mist (with a 25 L/min water flowrate) and 37% for the sprinkler (with a 91 L/min water flowrate). Fitting the infrared transmission spectra with results obtained using a Monte Carlo simulation provided an estimation of the water volumetric fraction in the spray. It was shown that the better attenuation capability of the water mist is due to two factors: (1) a higher extinction coefficient of the water mist for a given water volumetric fraction due to the small size of the injected droplets and (2) a higher water volumetric fraction. Opacity measurements in the visible range yielded a measured extinction coefficient in good agreement with an estimation obtained with the Mie theory and the identified water volumetric fraction. Moreover, the water sprays (sprinkler or water mist) was seen to lead to a quick de-stratification of the smoke layer. When the spraying operation was stopped, the visibility re-increased in two main steps: a first step of fast increase and a second step of slow increase needing a few tens of seconds to get again a fully stratified smoke

  3. Sound speed and oscillation frequencies for solar models evolved with Los Alamos ATOMIC opacities

    CERN Document Server

    Guzik, Joyce A; Walczak, P; Wood, S R; Mussack, K; Farag, E

    2016-01-01

    Los Alamos National Laboratory has calculated a new generation of radiative opacities (OPLIB data using the ATOMIC code) for elements with atomic number Z=1-30 with improved physics input, updated atomic data, and finer temperature grid to replace the Los Alamos LEDCOP opacities released in the year 2000. We calculate the evolution of standard solar models including these new opacities, and compare with models evolved using the Lawrence Livermore National Laboratory OPAL (Iglesias and Rogers 1996) opacities. We use the solar abundance mixture of Asplund et al. (2009). The new Los Alamos ATOMIC opacities have steeper opacity derivatives than those of OPAL for temperatures and densities of the solar interior radiative zone. We compare the calculated nonadiabatic solar oscillation frequencies and solar interior sound speed to observed frequencies and helioseismic inferences. The calculated sound-speed profiles are similar for models evolved using either the updated Iben evolution code (see \\cite{Guzik2010}), or ...

  4. Prevalence of Lens Opacities in Adult Chinese Americans: The Chinese American Eye Study (CHES)

    OpenAIRE

    Varma, Rohit; Sun, Jie; Torres, Mina; Wu, Shuang; Hsu, Chunyi; Azen, Stanley Paul; McKean-Cowdin, Roberta; ,

    2016-01-01

    Purpose We determined the age- and sex-specific prevalence of posterior subcapsular (PSC), nuclear, cortical, and mixed lens opacities in a population-based sample of Chinese-American adults. Methods A population-based sample of Chinese-Americans 50 years and older, from 10 census tracts in Monterey Park, CA, USA, underwent a detailed interview and a comprehensive clinical examination that included assessment of different types of lens opacities by the slit-lamp–based Lens Opacities Classific...

  5. FTS measurements of submillimeter opacity and other site testing at Pampa la Bola

    Science.gov (United States)

    Matsushita, Satoki; Matsuo, Hiroshi; Sakamoto, Akihiro; Pardo, Juan R.

    2000-07-01

    We have carried out Fourier Transform Spectrometer (FTS) measurements of the millimeter and submillimeter-wave (150 - 1500 GHz or 2 mm - 200 micrometer) atmospheric opacity at Pampa la Bola, 4800 m above sea level in northern Chile on September 1997 and June 1998. One of the best transmission spectra show up to approximately 67% transmission at well- known submillimeter-wave windows. Supra-terahertz windows (located around 1035 GHz, 1350 GHz, and 1500 GHz) were identified in the same spectrum. The observed spectra can be well modeled by newly developed radiative-transfer calculations. Correlations between 220 GHz opacities and those of the center of submillimeter-wave windows or even those of the supra-terahertz windows are obtained using the entire data set. Good correlations were obtained except for the periods affected by the liquid water opacity component. We succeeded to separate the total opacity in two parts: the water vapor opacity and the liquid water opacity, using two frequencies, one in the millimeter domain and another one in the submillimeter. The separated water vapor opacity component shows good correlation with the 183 GHz pure water vapor line opacity which is also covered in the measured spectra, but the liquid water opacity component shows no correlation. The liquid water opacity component also shows no correlation with the phase fluctuation measured with the 11 GHz radio seeing monitor. Modeling of this component is currently under way. Combined with a statistical study of the 225 GHz opacity data of the Chajnantor site (approximately 7 km apart from Pampa la Bola), it is estimated that submillimeter-wave observations can be done with zenith opacity less than 1.0 (at the most transparent frequency in those windows) for about 50% of the winter season, assuming no presence of liquid water absorption.

  6. Factors Affecting Corneal Hysteresis in Taiwanese Adults

    Institute of Scientific and Technical Information of China (English)

    Jia-Kang Wang; Tzu-Lun Huang; Pei-Yuan Su; Pei-Yao Chang

    2015-01-01

    Purpose: To investigate the correlation of various corneal hysteresis (CH) factors in Chinese adults. Methods: From January 2009 to November 2011, the healthy right eyes of a total of 292 adults were recruited into the study. Goldmann-correlated intraocular pressure (IOPG) and CH were measured using an ocular response analyzer (ORA). Central corneal thickness was measured using the ORA’s in-tegrated handheld ultrasonic pachymeter. The IOLMaster was used to obtain the ocular biometric measurements including axial length, anterior chamber depth, and keratometric values. The Pearson correlation coefficient was used to test correla-tions between CH and quantitative factors. The chi-square test was used to detect differences in categorical values. Results: Longer axial length (P=0.0001), lower IOPG (P=0.03), older age(P=0.003),and thinner central corneal thick-ness (P=0.0001) were significantly associated with lower CH. The anterior chamber depth (P=0.34), gender (P=0.23), and corneal curvature (P=0.18) had no relationship to CH. Conclusion:Various factors including axial length, intraocular pressure, age, and central corneal thickness can affect measure-ment of corneal biomechanical properties in Chinese adults. But the anterior chamber depth, gender, and corneal curvature were irrelevant to CH.

  7. Corneal sensitivity in five horse breeds

    Directory of Open Access Journals (Sweden)

    Eunice Santos de Andrade

    Full Text Available ABSTRACT: This study aimed to determine and compare corneal sensitivity values in different regions of the cornea in five horse breeds. One hundred and forty five healthy horses, adults of both sexes, of the following breeds - Arabian horse (AH; n=20, Mangalarga Marchador (MM; n=50, Pure Blood Lusitano (PBL; n=35, Quarter Horse (QH; n=20, Brazilian Sport Horse (BSH; n=20-were investigated. Corneal touch threshold (CTT was measured with a Cochet-Bonnet esthesiometer in five different corneal regions. Measurements of the median central CTT were: 4.50±0.50cm (AH, 3.50±0.56cm (MM, 3.00±0.25cm (PBL, 2.50±0.44cm (QH and 2.50±0.00cm (BSH. The central region was the most sensitive and the dorsal region the least sensitive corneal region for all breeds. CTT values differed for corneal regions and horse breeds. The CTT values were different among the corneal regions and the horse breeds. Arabian horses presented higher sensitivity values being the most sensitive in all of the corneal regions.

  8. Corneal topographic changes following retinal surgery

    Directory of Open Access Journals (Sweden)

    Pandey RM

    2004-08-01

    Full Text Available Abstract Background To study the effect of retinal/ vitreoretinal surgeries on corneal elevations. Methods Patients who underwent retinal/ vitreoretinal surgeries were divided into 3 groups. Scleral buckling was performed in 11 eyes (Group 1. In 8 (25% eyes, vitreoretinal surgery was performed along with scleral buckling (Group 2. In 12 eyes, pars plana vitrectomy was performed for vitreous hemorrhage (Group 3. An encircling element was used in all the eyes. The parameters evaluated were best-corrected visual acuity (BCVA, change in axial length, and corneal topographic changes on Orbscan topography system II, preoperative and at 12 weeks following surgery. Results There was a statistically significant increase in anterior corneal elevation in all the three groups after surgery (p = 0.003, p = 0.008 & p = 0.003 respectively. The increase in posterior corneal elevation was highly significant in all the three groups after surgery (p = 0.0000, p = 0.0001 & p = 0.0001 respectively. The increase in the posterior corneal elevation was more than the increase in the anterior elevation and was significant statistically in all the three groups (group I: p = 0.02; group II: p = 0.01; group III: p = 0.008. Conclusions Retinal/ vitreoretinal surgeries cause a significant increase in the corneal elevations and have a greater effect on the posterior corneal surface.

  9. Differences between real and predicted corneal shapes after aspherical corneal ablation

    Science.gov (United States)

    Anera, Rosario G.; Villa, César; Jiménez, José R.; Gutiérrez, Ramón; Jiménez del Barco, Luis

    2005-07-01

    We study the differences between real and expected corneal shapes, using an aspherical ablation algorithm with a known equation and avoiding the limitation imposed by most studies of refractive surgery in which the ablation equations are not known. We have calculated the theoretical corneal shape predicted by this algorithm, comparing this shape with the real corneal topography. The results indicate that the deviations that appear in the corneal shape are significant for visual performance and for the correction of eye aberrations. If we include in this analysis the effect of reflection losses and nonnormal incidence on the cornea, we can reduce corneal differences, but they will remain significant. These results confirm that it is essential to minimize corneal differences to achieve effective correction in refractive surgery.

  10. Detailed Opacity Comparison for an Improved Stellar Modeling of the Envelopes of Massive Stars

    Science.gov (United States)

    Turck-Chièze, S.; Le Pennec, M.; Ducret, J. E.; Colgan, J.; Kilcrease, D. P.; Fontes, C. J.; Magee, N.; Gilleron, F.; Pain, J. C.

    2016-06-01

    Seismic observations have led to doubts or ambiguities concerning the opacity calculations used in stellar physics. Here, we concentrate on the iron-group opacity peak, due to iron, nickel, and chromium, located around T = 200,000 K for densities from {10}-8 {to} {10}-4 {{g}} {{cm}}-3, which creates some convective layers in stellar radiative envelopes for masses between 3 and 18 {M}⊙ . These conditions were extensively studied in the 1980s. More recently, inconsistencies between OP and OPAL opacity calculations have complicated the interpretation of seismic observations as the iron-group opacity peak excites acoustic and gravity modes in SPB, β Cephei, and sdB stars. We investigate the reliability of the theoretical opacity calculations using the modern opacity codes ATOMIC and SCO-RCG. We show their temperature and density dependence for conditions that are achievable in the laboratory and equivalent to astrophysical conditions. We also compare new theoretical opacity spectra with OP spectra and quantify how different approximations impact the Rosseland mean calculations.This detailed study estimates new ATOMIC and SCO-RCG Rosseland mean values for astrophysical conditions which we compare to OP values. Some puzzling questions are still under investigation for iron, but we find a strong increase in the Rosseland mean nickel opacity of a factor between 2 and 6 compared to OP. This appears to be due to the use of extrapolated atomic data for the Ni opacity within the OP calculations. A study on chromium is also shown.

  11. Morphological evaluation of normal human corneal epithelium

    DEFF Research Database (Denmark)

    Ehlers, Niels; Heegaard, Steffen; Hjortdal, Jesper

    2010-01-01

    PURPOSE: The human corneal epithelium is usually described as a 50-µm-thick layer of regular stratified squamous non-keratinized cells with a thickness of 5-7 cells. The purpose of this study is systemically to revisit the histopathological appearance of 100 corneas. METHODS: 5-µm-thick sections...... in Bowman's membrane. No intraepithelial microcysts, as found in Meesmann corneal dystrophy, were observed. CONCLUSION: The total corneal thickness was higher than reported in in vivo studies and with a wider variation. This may be an effect of uncontrolled swelling and dehydration during preparation...

  12. Cataract surgery: emotional reactions of patients with monocular versus binocular vision Cirurgia de catarata: aspectos emocionais de pacientes com visão monocular versus binocular

    Directory of Open Access Journals (Sweden)

    Roberta Ferrari Marback

    2012-12-01

    Full Text Available PURPOSE: To analyze emotional reactions related to cataract surgery in two groups of patients (monocular vision - Group 1; binocular vision - Group 2. METHODS: A transversal comparative study was performed using a structured questionnaire from a previous exploratory study before cataract surgery. RESULTS: 206 patients were enrolled in the study, 96 individuals in Group 1 (69.3 ± 10.4 years and 110 in Group 2 (68.2 ± 10.2 years. Most patients in group 1 (40.6% and 22.7% of group 2, reported fear of surgery (pOBJETIVO: Verificar reações emocionais relacionadas à cirurgia de catarata entre pacientes com visão monocular (Grupo 1 e binocular (Grupo 2. MÉTODOS: Foi realizado um estudo tranversal, comparativo por meio de um questionário estruturado respondido por pacientes antes da cirurgia de catarata. RESULTADOS: A amostra foi composta de 96 pacientes no Grupo 1 (69.3 ± 10.4 anos e 110 no Grupo 2 (68.2 ± 10.2 anos. Consideravam apresentar medo da cirugia 40.6% do Grupo 1 e 22.7% do Grupo 2 (p<0.001 e entre as principais causas do medo, a possibilidade de perda da visão, complicações cirúrgicas e a morte durante o procedimento foram apontadas. Os sentimentos mais comuns entre os dois grupos foram dúvidas a cerca dos resultados da cirurgia e o nervosismo diante do procedimento. CONCLUSÃO: Pacientes com visão monocular apresentaram mais medo e dúvidas relacionadas à cirurgia de catarata comparados com aqueles com visão binocular. Portanto, é necessário que os médicos considerem estas reações emocionais e invistam mais tempo para esclarecer os riscos e benefícios da cirurgia de catarata.

  13. Evidence for Environmental Changes in the Submillimeter Dust Opacity

    CERN Document Server

    Martin, Peter G; Bontemps, Sylvain; Miville-Deschênes, Marc-Antoine; Ade, Peter A R; Bock, James J; Chapin, Edward L; Devlin, Mark J; Dicker, Simon R; Griffin, Matthew; Gundersen, Joshua O; Halpern, Mark; Hargrave, Peter C; Hughes, David H; Klein, Jeff; Marsden, Gaelen; Mauskopf, Philip; Netterfield, Calvin B; Olmi, Luca; Patanchon, Guillaume; Rex, Marie; Scott, Douglas; Semisch, Christopher; Truch, Matthew D P; Tucker, Carole; Tucker, Gregory S; Viero, Marco P; Wiebe, Donald V

    2011-01-01

    The submillimeter opacity of dust in the diffuse Galactic interstellar medium (ISM) has been quantified using a pixel-by-pixel correlation of images of continuum emission with a proxy for column density. We used three BLAST bands at 250, 350, and 500 \\mu m and one IRAS at 100 \\mu m. The proxy is the near-infrared color excess, E(J-Ks), obtained from 2MASS. Based on observations of stars, we show how well this color excess is correlated with the total hydrogen column density for regions of moderate extinction. The ratio of emission to column density, the emissivity, is then known from the correlations, as a function of frequency. The spectral distribution of this emissivity can be fit by a modified blackbody, whence the characteristic dust temperature T and the desired opacity \\sigma_e(1200) at 1200 GHz can be obtained. We have analyzed 14 regions near the Galactic plane toward the Vela molecular cloud, mostly selected to avoid regions of high column density (N_H > 10^{22} cm^-2) and small enough to ensure a u...

  14. Iron Opacity Platform Performance Characterization at the National Ignition Facility

    Science.gov (United States)

    Opachich, Y. P.; Ross, P. W.; Heeter, R. F.; Barrios, M. A.; Liedahl, D. A.; May, M. J.; Schneider, M. B.; Craxton, R. S.; Garcia, E. M.; McKenty, P. W.; Zhang, R.; Weaver, J. L.; Flippo, K. A.; Kline, J. L.; Perry, T. S.; Los Alamos National Laboratory Collaboration; Naval Research Laboratory Collaboration; University of Rochester LaboratoryLaser Energetics Collaboration; Lawrence Livermore National Lab Collaboration; National Security Technologies, LLC Collaboration

    2016-10-01

    A high temperature opacity platform has been fielded at the National Ignition Facility (NIF). The platform will be used to study opacity in iron at a temperature of 160 eV. The platform uses a 6 mm diameter hohlraum driven by 128 laser beams with 530 kJ of energy in a 3 ns pulse to heat an iron sample. Absorption spectra of the heated sample are generated with a broadband pulsed X-ray backlighter produced by imploding a vacuum-filled CH shell. The shell is 2 mm in diameter and 20 microns thick, driven by 64 beams with 250 kJ in a 2.5 ns pulse. The hohlraum and backlighter performance have both been investigated recently and will be discussed in this presentation. This work was performed by National Security Technologies, LLC, under Contract No. DE-AC52-06NA25946 with the U.S. Department of Energy. DOE/NV/25946-2892.

  15. Iron Opacity and the Pulsar of SN 1987A

    CERN Document Server

    Fryer, C L; Pinto, P A

    1999-01-01

    Neutron stars formed in Type II supernovae are likely to be initially obscured by late-time fallback. Although much of the late-time fallback is quickly accreted via neutrino cooling, some material remains on the neutron star, forming an atmosphere which slowly accretes through photon emission. In this paper, we derive structure equations of the fallback atmosphere and present results of one-dimensional simulations of that fallback. The atmosphere remaining after neutrino cooling becomes unimportant (less than the Compton Eddington limit) is only a fraction of the total mass accreted (10^-8 of the accreted mass or 10^-9 solar masses.) Recombined iron dominates the opacity in the outer regions leading to an opacity 1000-10,000 times higher than that of electron scattering alone. The resultant photon emission of the remnant atmosphere is limited to 1/1000th the Compton Eddington Luminosity. The late-time evolution of this system leads to the formation of a photon-driven wind from the accretion of the inner port...

  16. New dust opacity mapping from Viking Infrared Thermal Mapper data

    Science.gov (United States)

    Martin, Terry Z.; Richardson, Mark I.

    1993-01-01

    Global dust opacity mapping for Mars has been carried forward using the approach described by Martin (1986) for Viking IR Thermal Mapper data. New maps are presented for the period from the beginning of Viking observations, until Ls 210 deg in 1979 (1.36 Mars years). This range includes the second and more extensive planet-encircling dust storm observed by Viking, known as storm 1977b. Improvements in approach result in greater time resolution and smaller noise than in the earlier work. A strong local storm event filled the Hellas basin at Ls 170 deg, prior to the 1977a storm. Dust is retained in equatorial regions following the 1977b storm far longer than in mid-latitudes. Minor dust events appear to raise the opacity in northern high latitudes during northern spring. Additional mapping with high time resolution has been done for the periods of time near the major storm origins in order to search for clues to the mechanism of storm initiation. The first evidence of the start of the 1977b storm is pushed back to Ls 274.2 deg, preceding signs of the storm in images by about 15 hours.

  17. Galactic cold cores VI. Dust opacity spectral index

    CERN Document Server

    Juvela, M; Doi, Y; Hughes, A; Lefevre, C; Marshall, D J; Meny, C; Montillaud, J; Pagani, L; Paradis, D; Ristorcelli, I; Malinen, J; Montier, L A; Paladini, R; Pelkonen, V -M; Rivera-Ingraham, A

    2015-01-01

    The Galactic Cold Cores project has made Herschel observations of 116 fields where the Planck survey has found signs of cold dust emission. The fields contain sources in different environments and different phases of star formation. The dust opacity spectral index beta and the dust colour temperature T are derived using Herschel and Planck data. The relation between beta and T is examined for the whole sample and inside individual fields. Based on IRAS and Planck data, the fields are characterised by a median colour temperature of 16.1 K and a median opacity spectral index of beta=1.84. We observe a clear T-beta anti-correlation. In Herschel observations, constrained at lower resolution by Planck data, the variations follow the column density structure and beta(FIR) can rise to ~2.2 in individual clumps. The Planck 217 GHz band shows a systematic excess that is consistent with a general flattening of the dust emission spectrum at millimetre wavelengths. When fitted separately below and above 700 um, the media...

  18. Cirurgia monocular para esotropias de grande ângulo: histórico e novos paradigmas Monocular surgery for large-angle esotropias: review and new paradigms

    Directory of Open Access Journals (Sweden)

    Edmilson Gigante

    2010-08-01

    Full Text Available As primitivas cirurgias de estrabismo, as miotomias e as tenotomias, eram feitas, simplesmente, seccionando-se o músculo ou o seu tendão, sem nenhuma sutura. Estas cirurgias eram feitas, geralmente, em um só olho, tanto em pequenos como em grandes desvios e os resultados eram pouco previsíveis. Jameson, em 1922, propôs uma nova técnica cirúrgica, usando suturas e fixando, na esclera, o músculo seccionado, tornando a cirurgia mais previsível. Para as esotropias, praticou recuos de, no máximo, 5 mm para o reto medial, o que se tornou uma regra para os demais cirurgiões que o sucederam, sendo impossível, a partir daí, a correção de esotropias de grande ângulo com cirurgia monocular. Rodriguez-Vásquez, em 1974, superou o parâmetro de 5 mm, propondo amplos recuos dos retos mediais (6 a 9 mm para o tratamento da síndrome de Ciancia, com bons resultados. Os autores revisaram a literatura, ano a ano, objetivando comparar os vários trabalhos e, com isso, concluíram que a cirurgia monocular de recuo-ressecção pode constituir uma opção viável para o tratamento cirúrgico das esotropias de grande ângulo.The primitive strabismus surgeries, myotomies and tenotomies, were performed simply by sectioning the muscle or its tendon without any suture. Such surgeries were usually performed in just one eye both in small and in large angles with not really predictable results. In 1922, Jameson introduced a new surgery technique using sutures and fixing the sectioned muscle to the sclera, increasing surgery predictability. For the esotropias he carried out no more than 5 mm recession of the medial rectus, which became a rule for the surgeons who followed him, which made it impossible from then on to correct largeangle esotropias with a monocular surgery. Rodriguez-Vásquez, in 1974, exceeded the 5 mm parameter by proposing large recessions of the medial recti (6 to 9 mm to treat the Ciancia syndrome with good results. The authors revised the

  19. Polar Value Analysis of Corneal Astigmatism in Intrastromal Corneal Ring Segment Implantation

    Science.gov (United States)

    Rho, Chang Rae; Kim, Min-Ji

    2016-01-01

    Purpose. To evaluate surgically induced astigmatism (SIA) and the average corneal power change in symmetric intrastromal corneal ring segment (ICRS) implantation. Methods. The study included 34 eyes of 34 keratoconus patients who underwent symmetric Intacs SK ICRS implantation. The corneal pocket incision meridian was the preoperative steep meridian. Corneal power data were obtained before and 3 months after Intacs SK ICRS implantation using scanning-slit topography. Polar value analysis was used to evaluate the SIA. Hotelling's trace test was used to compare intraindividual changes. Results. Three months postoperatively, the combined mean polar value for SIA changed significantly (Hotelling's T2 = 0.375; P = 0.006). The SIA was 1.54 D at 99° and the average corneal power decreased significantly by 3.8 D. Conclusion. Intacs SK ICRS placement decreased the average corneal power and corneal astigmatism compared to the preoperative corneal power and astigmatism when the corneal pocket incision was made at the preoperative steep meridian. PMID:27795856

  20. Polar Value Analysis of Corneal Astigmatism in Intrastromal Corneal Ring Segment Implantation

    Directory of Open Access Journals (Sweden)

    Chang Rae Rho

    2016-01-01

    Full Text Available Purpose. To evaluate surgically induced astigmatism (SIA and the average corneal power change in symmetric intrastromal corneal ring segment (ICRS implantation. Methods. The study included 34 eyes of 34 keratoconus patients who underwent symmetric Intacs SK ICRS implantation. The corneal pocket incision meridian was the preoperative steep meridian. Corneal power data were obtained before and 3 months after Intacs SK ICRS implantation using scanning-slit topography. Polar value analysis was used to evaluate the SIA. Hotelling’s trace test was used to compare intraindividual changes. Results. Three months postoperatively, the combined mean polar value for SIA changed significantly (Hotelling’s T2=0.375; P=0.006. The SIA was 1.54 D at 99° and the average corneal power decreased significantly by 3.8 D. Conclusion. Intacs SK ICRS placement decreased the average corneal power and corneal astigmatism compared to the preoperative corneal power and astigmatism when the corneal pocket incision was made at the preoperative steep meridian.

  1. Evaluación de la reproducibilidad de la retinoscopia dinámica monocular de Merchán

    Directory of Open Access Journals (Sweden)

    Lizbeth Acuña

    2010-08-01

    Full Text Available Objetivo: Evaluar la reproducibilidad de la retinoscopia dinámica monocular y su nivel de acuerdo con la retinoscopia estática binocular y monocular, retinoscopia de Nott y Método Estimado Monocular (MEM. Métodos: Se determinó la reproducibilidad entre los evaluadores y entre los métodos por medio del coeficiente de correlación intraclase (CCI y se establecieron los límites de acuerdo de Bland y Altman. Resultados: Se evaluaron 126 personas entre 5 y 39 años y se encontró una baja reproducibilidad interexaminador de la retinoscopia dinámica monocular en ambos ojos CCI ojo derecho: 0.49 (IC95% 0.36; 0.51; ojo izquierdo 0.51 (IC95% 0.38; 0.59. El límite de acuerdo entre evaluadores fue ±1.25 D. Al evaluar la reproducibilidad entre la retinoscopia dinámica monocular y la estática se observó que la mayor reproducibilidad se obtuvo con la estática binocular y monocular y, en visión próxima, entre el método estimado monocular y la retinoscopia de Nott. Conclusiones: La retinoscopia dinámica monocular no es una prueba reproducible y presenta diferencias clínicas significativas para determinar el estado refractivo, en cuanto a poder dióptrico y tipo de ametropía, por tanto, no se puede considerar dentro de la batería de exámenes aplicados para determinar diagnósticos y correcciones refractivas tanto en la visión lejana como en la visión próxima.

  2. Evaluación de la reproducibilidad de la retinoscopia dinámica monocular de Merchán

    Directory of Open Access Journals (Sweden)

    Lizbeth Acuña

    2009-12-01

    Full Text Available Objetivo: Evaluar la reproducibilidad de la retinoscopia dinámica monocular y su nivel de acuerdo con la retinoscopia estática binocular y monocular, retinoscopia de Nott y Método Estimado Monocular (MEM.Métodos: Se determinó la reproducibilidad entre los evaluadores y entre los métodos por medio del coeficiente de correlación intraclase (CCI y se establecieron los límites de acuerdo de Bland y Altman.Resultados: Se evaluaron 126 personas entre 5 y 39 años y se encontró una baja reproducibilidad interexaminador de la retinoscopia dinámica monocular en ambos ojos CCI ojo derecho: 0.49 (IC95% 0.36; 0.51; ojo izquierdo 0.51 (IC95% 0.38; 0.59. El límite de acuerdo entre evaluadores fue ±1.25 D. Al evaluar la reproducibilidad entre la retinoscopia dinámica monocular y la estática se observó que la mayor reproducibilidad se obtuvo con la estática binocular y monocular y, en visión próxima, entre el método estimado monocular y la retinoscopia de Nott.Conclusiones: La retinoscopia dinámica monocular no es una prueba reproducible y presenta diferencias clínicas significativas para determinar el estado refractivo, en cuanto a poder dióptrico y tipo de ametropía, por tanto, no se puede considerar dentro de la batería de exámenes aplicados para determinar diagnósticos y correcciones refractivas tanto en la visión lejana como en la visión próxima.

  3. MMSC-LIKE LIMBAL CELLS COTRANSPLANTATION PROMOTES LOCAL IMMUNOCORRECTION AND CORNEAL GRAFT TRANSPARENT RETENTION IN HIGH RISK KERATOPLASTY

    Directory of Open Access Journals (Sweden)

    S. A. Borzenok

    2014-01-01

    Full Text Available Aim was to evaluate clinical results of donor corneal graft survival in high-risk recipients in co-transplantation of preserved allogenic limbal grafts. Materials and methods. Two types of penetrative keratoplasties were carried out in patients with corneal graft opacities and high risk of rejection (n = 69. Co-transplantation of donor cornea and allogenic MMSC-like limbal cells in the form of limbal transplants was carried out in the 1st group (n = 36; in the 2nd group (n = 33 only the cornea was transplanted. Results. Observation of the patients during one year after surgery showed that the rate of transparent cornea engraftment increased in the 1st group (86,1 against 69,7% in the 2nd group. The density of endothelial cells was also higher in the 1st group (85,9 against 76,2% in the 2nd group. At the same time, progressive decreasing of pro-inflammatory cytokines (IL-6, IFNγ, TNFα and increasing of anti-inflammatory cytokines (IL-10, IL-1RA, TGFβ along with higher level of HLA-G5 were revealed in the recipients’ tear fluid in the 1st group in comparison to the 2nd group. Conclusion. Simultaneous transplantation of preserved limbal grafts with corneal graft in high-risk keratoplasty favors the transparent cornea engraftment, obviously, this is due to immunoregulatory activity of the MMSC-like limbal cells. 

  4. Keratitis after Implantation of Intrastromal Corneal Rings with Spontaneous Extrusion of the Segment

    Directory of Open Access Journals (Sweden)

    Juan Ibáñez-Alperte

    2010-09-01

    Full Text Available Purpose: To report a case of bacterial keratitis in a patient with a history of intrastromal corneal ring segments (INTACS® implantation to correct keratoconus. Methods: The patient’s history, clinical presentation, pathological analysis and therapeutic management were reviewed. Results: A 36-year-old-man was referred to our department due to decreased vision and intense pain in his left eye, 40 days after INTACS® implantation for keratoconus. Slit-lamp examination revealed epithelial defects and stromal infiltrates in the lower channel without evidence of the inferior ring. The anterior chamber also showed a significant fibrin reaction to hypopyon. A low-tension suture was removed at the site of the incision. Microbiological study of the conjunctival swab was positive for Staphylococcus epidermidis, but the corneal culture was sterile. The patient was treated with topical fortified and systemic antibiotics. The infection slowly resolved, leaving opacity at the inferior segment site. Conclusions: Infectious keratitis following INTACS implantation is an infrequent complication that can have important consequences without suitable and early therapeutic management.

  5. Surgical compensation of presbyopia with corneal inlays.

    Science.gov (United States)

    Konstantopoulos, Aris; Mehta, Jodhbir S

    2015-05-01

    Presbyopia, the physiological change in near vision that develops with ageing, gradually affects individuals older than 40 years and is a growing cause of visual disability due to ageing demographics of the global population. The routine use of computers and 'smartphones', combined with the affluence of the 'baby boomers' generation has set high standards for near vision correction. Corneal inlays are a relatively new treatment modality that is effective at compensating for presbyopia. The dimensions of these devices vary from 2 to 3.8 mm in diameter and 5 to 32 μm in thickness. They are implanted in the anterior corneal stroma of the non-dominant eye, most commonly, in a femtosecond laser created corneal pocket. They improve near vision by increasing the depth of focus, creating a hyper-prolate region of increased central cornea power or providing a refractive add power. This article reviews the literature on the efficacy and safety of corneal inlays.

  6. Conjunctival intraepithelial neoplasia with corneal furrow degeneration

    Directory of Open Access Journals (Sweden)

    Pukhraj Rishi

    2014-01-01

    Full Text Available A 68-year-old man presented with redness of left eye since six months. Examination revealed bilateral corneal furrow degeneration. Left eye lesion was suggestive of conjunctival squamous cell carcinoma, encroaching on to cornea. Anterior segment optical coherence tomography (AS-OCT confirmed peripheral corneal thinning. Fluorescein angiography confirmed intrinsic vascularity of lesion. Patient was managed with "no touch" surgical excision, dry keratectomy without alcohol, cryotherapy, and primary closure. Pathologic examination of removed tissue confirmed clinical diagnosis. Management of this particular case required modification of standard treatment protocol. Unlike the alcohol-assisted technique of tumor dissection described, ethyl alcohol was not used for risk of corneal perforation due to underlying peripheral corneal thinning. Likewise, topical steroids were withheld in the post-operative period. Three weeks post-operatively, left eye was healing well. Hence, per-operative usage of absolute alcohol and post-operative use of topical steroids may be best avoided in such eyes.

  7. Grain opacity and the bulk composition of extrasolar planets. II. An analytical model for the grain opacity in protoplanetary atmospheres

    CERN Document Server

    Mordasini, C

    2014-01-01

    Context. We investigate the grain opacity k_gr in the atmosphere of protoplanets. This is important for the planetary mass-radius relation since k_gr affects the H/He envelope mass of low-mass planets and the critical core mass of giant planets. Aims. The goal of this study is to derive an analytical model for k_gr. Methods. Our model is based on the comparison of the timescales of microphysical processes like grain settling in the Stokes and Epstein regime, growth by Brownian motion coagulation and differential settling, grain evaporation, and grain advection due to envelope contraction. With these timescales we derive the grain size, abundance, and opacity. Results. We find that the main growth process is differential settling. In this regime, k_gr has a simple functional form and is given as 27 Q/8 H rho in the Epstein regime and as 2 Q/H rho for Stokes drag. Grain dynamics lead to a typical radial structure of k_gr with high ISM-like values in the top layers but a strong decrease in the deeper parts where...

  8. Induction of Monocular Stereopsis by Altering Focus Distance: A Test of Ames’s Hypothesis

    Directory of Open Access Journals (Sweden)

    Dhanraj Vishwanath

    2016-04-01

    Full Text Available Viewing a real three-dimensional scene or a stereoscopic image with both eyes generates a vivid phenomenal impression of depth known as stereopsis. Numerous reports have highlighted the fact that an impression of stereopsis can be induced in the absence of binocular disparity. A method claimed by Ames (1925 involved altering accommodative (focus distance while monocularly viewing a picture. This claim was tested on naïve observers using a method inspired by the observations of Gogel and Ogle on the equidistance tendency. Consistent with Ames’s claim, most observers reported that the focus manipulation induced an impression of stereopsis comparable to that obtained by monocular-aperture viewing.

  9. Embolic and nonembolic transient monocular visual field loss: a clinicopathologic review.

    Science.gov (United States)

    Petzold, Axel; Islam, Niaz; Hu, Han-Hwa; Plant, Gordon T

    2013-01-01

    Transient monocular blindness and amaurosis fugax are umbrella terms describing a range of patterns of transient monocular visual field loss (TMVL). The incidence rises from ≈1.5/100,000 in the third decade of life to ≈32/100,000 in the seventh decade of life. We review the vascular supply of the retina that provides an anatomical basis for the types of TMVL and discuss the importance of collaterals between the external and internal carotid artery territories and related blood flow phenomena. Next, we address the semiology of TMVL, focusing on onset, pattern, trigger factors, duration, recovery, frequency-associated features such as headaches, and on tests that help with the important differential between embolic and non-embolic etiologies.

  10. A monocular vision system based on cooperative targets detection for aircraft pose measurement

    Science.gov (United States)

    Wang, Zhenyu; Wang, Yanyun; Cheng, Wei; Chen, Tao; Zhou, Hui

    2017-08-01

    In this paper, a monocular vision measurement system based on cooperative targets detection is proposed, which can capture the three-dimensional information of objects by recognizing the checkerboard target and calculating of the feature points. The aircraft pose measurement is an important problem for aircraft’s monitoring and control. Monocular vision system has a good performance in the range of meter. This paper proposes an algorithm based on coplanar rectangular feature to determine the unique solution of distance and angle. A continuous frame detection method is presented to solve the problem of corners’ transition caused by symmetry of the targets. Besides, a displacement table test system based on three-dimensional precision and measurement system human-computer interaction software has been built. Experiment result shows that it has a precision of 2mm in the range of 300mm to 1000mm, which can meet the requirement of the position measurement in the aircraft cabin.

  11. Monocular trajectory intersection method for 3D motion measurement of a point target

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This article proposes a monocular trajectory intersection method,a videometrics measurement with a mature theoretical system to solve the 3D motion parameters of a point target.It determines the target’s motion parameters including its 3D trajectory and velocity by intersecting the parametric trajectory of a motion target and series of sight-rays by which a motion camera observes the target,in contrast with the regular intersection method for 3D measurement by which the sight-rays intersect at one point.The method offers an approach to overcome the technical failure of traditional monocular measurements for the 3D motion of a point target and thus extends the application fields of photogrammetry and computer vision.Wide application is expected in passive observations of motion targets on various mobile beds.

  12. A Novel Ship-Bridge Collision Avoidance System Based on Monocular Computer Vision

    Directory of Open Access Journals (Sweden)

    Yuanzhou Zheng

    2013-06-01

    Full Text Available The study aims to investigate the ship-bridge collision avoidance. A novel system for ship-bridge collision avoidance based on monocular computer vision is proposed in this study. In the new system, the moving ships are firstly captured by the video sequences. Then the detection and tracking of the moving objects have been done to identify the regions in the scene that correspond to the video sequences. Secondly, the quantity description of the dynamic states of the moving objects in the geographical coordinate system, including the location, velocity, orientation, etc, has been calculated based on the monocular vision geometry. Finally, the collision risk is evaluated and consequently the ship manipulation commands are suggested, aiming to avoid the potential collision. Both computer simulation and field experiments have been implemented to validate the proposed system. The analysis results have shown the effectiveness of the proposed system.

  13. Depth measurement using monocular stereo vision system: aspect of spatial discretization

    Science.gov (United States)

    Xu, Zheng; Li, Chengjin; Zhao, Xunjie; Chen, Jiabo

    2010-11-01

    The monocular stereo vision system, consisting of single camera with controllable focal length, can be used in 3D reconstruction. Applying the system for 3D reconstruction, must consider effects caused by digital camera. There are two possible methods to make the monocular stereo vision system. First one the distance between the target object and the camera image plane is constant and lens moves. The second method assumes that the lens position is constant and the image plane moves in respect to the target. In this paper mathematical modeling of two approaches is presented. We focus on iso-disparity surfaces to define the discretization effect on the reconstructed space. These models are implemented and simulated on Matlab. The analysis is used to define application constrains and limitations of these methods. The results can be also used to enhance the accuracy of depth measurement.

  14. Monocular trajectory intersection method for 3D motion measurement of a point target

    Institute of Scientific and Technical Information of China (English)

    YU QiFeng; SHANG Yang; ZHOU Jian; ZHANG XiaoHu; LI LiChun

    2009-01-01

    This article proposes a monocular trajectory intersection method,a videometrics measurement with a mature theoretical system to solve the 3D motion parameters of a point target.It determines the target's motion parameters including its 3D trajectory and velocity by intersecting the parametric trajectory of a motion target and series of sight-rays by which a motion camera observes the target,in contrast with the regular intersection method for 3D measurement by which the sight-rays intersect at one point.The method offers an approach to overcome the technical failure of traditional monocular measurements for the 3D motion of a point target and thus extends the application fields of photogrammetry and computer vision.Wide application is expected in passive observations of motion targets on various mobile beds.

  15. Large-scale monocular FastSLAM2.0 acceleration on an embedded heterogeneous architecture

    Science.gov (United States)

    Abouzahir, Mohamed; Elouardi, Abdelhafid; Bouaziz, Samir; Latif, Rachid; Tajer, Abdelouahed

    2016-12-01

    Simultaneous localization and mapping (SLAM) is widely used in many robotic applications and autonomous navigation. This paper presents a study of FastSLAM2.0 computational complexity based on a monocular vision system. The algorithm is intended to operate with many particles in a large-scale environment. FastSLAM2.0 was partitioned into functional blocks allowing a hardware software matching on a CPU-GPGPU-based SoC architecture. Performances in terms of processing time and localization accuracy were evaluated using a real indoor dataset. Results demonstrate that an optimized and efficient CPU-GPGPU partitioning allows performing accurate localization results and high-speed execution of a monocular FastSLAM2.0-based embedded system operating under real-time constraints.

  16. Corneal topography and soft contact lens fit.

    Science.gov (United States)

    Young, Graeme; Schnider, Cristina; Hunt, Chris; Efron, Suzanne

    2010-05-01

    To determine which ocular topography variables affect soft contact lens fit. Fifty subjects each wore three pairs of soft lenses in random succession (Vistakon Acuvue 2, Vistakon Acuvue Advance, Ciba Vision Night & Day), and various aspects of lens fit were evaluated. The steeper base curves of each type were worn in one eye and the flatter base curves in the other eye. Corneal topography data were collected using a Medmont E300 corneal topographer (Camberwell, Australia). Corneal curvature, shape factor (SF), and corneal height were measured over a 10 mm chord and also over the maximum measurable diameter. These were measured in the horizontal, vertical, steepest, and flattest meridians. With each lens type, the steeper base curve provided the best fit on the greatest proportion of eyes and the significant differences in various aspects of fit were noted between base curves. For each lens type, there was no significant difference in mean K-reading between those eyes best fit with the steeper base curve and those eyes best fit with the flatter base curve. Two of the lenses showed a positive correlation between centration and horizontal corneal height (maximum), whereas one lens showed a negative correlation between centration and horizontal SF (SF = e). Several lenses showed a positive correlation between post-blink movement and horizontal or vertical corneal SF. The measurement of corneal topography using current Placido disc instrumentation allows a better prediction of soft lens fit than by keratometry, but it is not reliable enough to enable accurate selection of the best fitting base curve. Some correlations are evident between corneal measurements; however, trial fitting remains the method of choice for selection of soft lens base curve.

  17. Serological profile of candidates for corneal donation

    OpenAIRE

    Adroaldo Lunardelli; Richard Beraldini Alvarenga; Maria Luiza Assmann; Dário Eduardo de Lima Brum; Mirna Adolfina Barison

    2014-01-01

    Objetive: The purpose of this study is to map the serological profile of candidates to corneal donation at Irmandade Santa Casa de Misericórdia de Porto Alegre, identifying the percentage of disposal by serology and the marker involved. Methods: There have been analised – retrospectively – the results of serology of all corneal donors, made between the period of 1st january 2006 and 31st december 2012. Data analised were related to age, gender and the results of serology pert...

  18. A Case of Recurrent Transient Monocular Visual Loss after Receiving Sildenafil

    Directory of Open Access Journals (Sweden)

    Asaad Ghanem Ghanem

    2011-01-01

    Full Text Available A 53-year-old man was attended to the Clinic Ophthalmic Center, Mansoura University, Egypt, with recurrent transient monocular visual loss after receiving sildenafil citrate (Viagra for erectile dysfunction. Examination for possible risk factors revealed mild hypercholesterolemia. Family history showed that his father had suffered from bilateral nonarteritic anterior ischemic optic neuropathy (NAION. Physicians might look for arteriosclerotic risk factors and family history of NAION among predisposing risk factors before prescribing sildenafil erectile dysfunction drugs.

  19. Benign pituitary adenoma associated with hyperostosis of the spenoid bone and monocular blindness. Case report.

    Science.gov (United States)

    Milas, R W; Sugar, O; Dobben, G

    1977-01-01

    The authors describe a case of benign chromophobe adenoma associated with hyperostosis of the lesser wing of the sphenoid bone and monocular blindness in a 38-year-old woman. The endocrinological and radiological evaluations were all suggestive of a meningioma. The diagnosis was established by biopsy of the tumor mass. After orbital decompression and removal of the tumor, the patient was treated with radiation therapy. Her postoperative course was uneventful, and her visual defects remained fixed.

  20. Asphericity analysis using corneal wavefront and topographic meridional fits

    Science.gov (United States)

    Arba-Mosquera, Samuel; Merayo-Lloves, Jesús; de Ortueta, Diego

    2010-03-01

    The calculation of corneal asphericity as a 3-D fit renders more accurate results when it is based on the corneal wavefront aberrations rather than on the corneal topography of the principal meridians. A more accurate prediction could be obtained for hyperopic treatments compared to myopic treatments. We evaluate a method to calculate corneal asphericity and asphericity changes after refractive surgery. Sixty eyes of 15 consecutive myopic patients and 15 consecutive hyperopic patients (n=30 each) are retrospectively evaluated. Preoperative and 3-month-postoperative topographic and corneal wavefront analyses are performed using corneal topography. Ablations are performed using a laser with an aberration-free profile. Topographic changes in asphericity and corneal aberrations are evaluated for a 6-mm corneal diameter. The induction of corneal spherical aberrations and asphericity changes correlates with the achieved defocus correction. Preoperatively as well as postoperatively, asphericity calculated from the topography meridians correlates with asphericity calculated from the corneal wavefront in myopic and hyperopic treatments. A stronger correlation between postoperative asphericity and the ideally expected/predicted asphericity is obtained based on aberration-free assumptions calculated from corneal wavefront values rather than from the meridians. In hyperopic treatments, a better correlation can be obtained compared to the correlation in myopic treatments. Corneal asphericity calculated from corneal wavefront aberrations represents a 3-D fit of the corneal surface; asphericity calculated from the main topographic meridians represents a 2-D fit of the principal corneal meridians. Postoperative corneal asphericity can be calculated from corneal wavefront aberrations with higher fidelity than from corneal topography of the principal meridians. Hyperopic treatments show a greater accuracy than myopic treatments.

  1. Ocular irritation reversibility assessment for personal care products using a porcine corneal culture assay.

    Science.gov (United States)

    Donahue, Douglas A; Avalos, Javier; Kaufman, Lewis E; Simion, F Anthony; Cerven, Daniel R

    2011-04-01

    Personal care product manufacturers have used a broad spectrum of alternative ocular irritation assays during the past two decades because these tests do not require the use of live animals, they provide reliable predictive data, and they are relatively inexpensive to conduct. To complement these assays, the ex vivo Porcine Corneal Opacity Reversibility Assay (PorCORA) was recently developed using a corneal culture model to predict reversibility of ocular irritants. Three commercially available consumer products (a shampoo, a hair color glaze, and a hair colorant system containing 12% hydrogen peroxide) were each tested in two PorCORA study replicates in order to assess potential ocular damage reversibility for surfactant-, propylene carbonate-, and peroxide-based formulations, respectively. Under the exaggerated, in vitro study conditions, the surfactant-based shampoo may cause irreversible porcine corneal damage (histological changes in the epithelial squamous cell and/or basal cell layers), whereas the hair color glaze and 12% hydrogen peroxide product caused fully reversible ocular irritation (microscopic changes only in the superficial squamous cell layer). The hair color glaze and peroxide product results correlate with established in vivo data for similar compounds, but the shampoo results contradicted previous BCOP results (expected to be only a mild irritant). Therefore, although the PorCORA protocol shows promise in predicting the extent and reversibility of potential ocular damage caused by accidental consumer eye exposure to personal care products, the contradictory results for the surfactant-based shampoo indicate that more extensive validation testing of the PorCORA is necessary to definitively establish the protocol's reliability as a Draize test replacement.

  2. Autocalibrating vision guided navigation of unmanned air vehicles via tactical monocular cameras in GPS denied environments

    Science.gov (United States)

    Celik, Koray

    This thesis presents a novel robotic navigation strategy by using a conventional tactical monocular camera, proving the feasibility of using a monocular camera as the sole proximity sensing, object avoidance, mapping, and path-planning mechanism to fly and navigate small to medium scale unmanned rotary-wing aircraft in an autonomous manner. The range measurement strategy is scalable, self-calibrating, indoor-outdoor capable, and has been biologically inspired by the key adaptive mechanisms for depth perception and pattern recognition found in humans and intelligent animals (particularly bats), designed to assume operations in previously unknown, GPS-denied environments. It proposes novel electronics, aircraft, aircraft systems, systems, and procedures and algorithms that come together to form airborne systems which measure absolute ranges from a monocular camera via passive photometry, mimicking that of a human-pilot like judgement. The research is intended to bridge the gap between practical GPS coverage and precision localization and mapping problem in a small aircraft. In the context of this study, several robotic platforms, airborne and ground alike, have been developed, some of which have been integrated in real-life field trials, for experimental validation. Albeit the emphasis on miniature robotic aircraft this research has been tested and found compatible with tactical vests and helmets, and it can be used to augment the reliability of many other types of proximity sensors.

  3. Monocular blur alters the tuning characteristics of stereopsis for spatial frequency and size.

    Science.gov (United States)

    Li, Roger W; So, Kayee; Wu, Thomas H; Craven, Ashley P; Tran, Truyet T; Gustafson, Kevin M; Levi, Dennis M

    2016-09-01

    Our sense of depth perception is mediated by spatial filters at different scales in the visual brain; low spatial frequency channels provide the basis for coarse stereopsis, whereas high spatial frequency channels provide for fine stereopsis. It is well established that monocular blurring of vision results in decreased stereoacuity. However, previous studies have used tests that are broadband in their spatial frequency content. It is not yet entirely clear how the processing of stereopsis in different spatial frequency channels is altered in response to binocular input imbalance. Here, we applied a new stereoacuity test based on narrow-band Gabor stimuli. By manipulating the carrier spatial frequency, we were able to reveal the spatial frequency tuning of stereopsis, spanning from coarse to fine, under blurred conditions. Our findings show that increasing monocular blur elevates stereoacuity thresholds 'selectively' at high spatial frequencies, gradually shifting the optimum frequency to lower spatial frequencies. Surprisingly, stereopsis for low frequency targets was only mildly affected even with an acuity difference of eight lines on a standard letter chart. Furthermore, we examined the effect of monocular blur on the size tuning function of stereopsis. The clinical implications of these findings are discussed.

  4. Short-term monocular patching boosts the patched eye’s response in visual cortex

    Science.gov (United States)

    Zhou, Jiawei; Baker, Daniel H.; Simard, Mathieu; Saint-Amour, Dave; Hess, Robert F.

    2015-01-01

    Abstract Purpose: Several recent studies have demonstrated that following short-term monocular deprivation in normal adults, the patched eye, rather than the unpatched eye, becomes stronger in subsequent binocular viewing. However, little is known about the site and nature of the underlying processes. In this study, we examine the underlying mechanisms by measuring steady-state visual evoked potentials (SSVEPs) as an index of the neural contrast response in early visual areas. Methods: The experiment consisted of three consecutive stages: a pre-patching EEG recording (14 minutes), a monocular patching stage (2.5 hours) and a post-patching EEG recording (14 minutes; started immediately after the removal of the patch). During the patching stage, a diffuser (transmits light but not pattern) was placed in front of one randomly selected eye. During the EEG recording stage, contrast response functions for each eye were measured. Results: The neural responses from the patched eye increased after the removal of the patch, whilst the responses from the unpatched eye remained the same. Such phenomena occurred under both monocular and dichoptic viewing conditions. Conclusions: We interpret this eye dominance plasticity in adult human visual cortex as homeostatic intrinsic plasticity regulated by an increase of contrast-gain in the patched eye. PMID:26410580

  5. Measuring method for the object pose based on monocular vision technology

    Science.gov (United States)

    Sun, Changku; Zhang, Zimiao; Wang, Peng

    2010-11-01

    Position and orientation estimation of the object, which can be widely applied in the fields as robot navigation, surgery, electro-optic aiming system, etc, has an important value. The monocular vision positioning algorithm which is based on the point characteristics is studied and new measurement method is proposed in this paper. First, calculate the approximate coordinates of the five reference points which can be used as the initial value of iteration in the camera coordinate system according to weakp3p; Second, get the exact coordinates of the reference points in the camera coordinate system through iterative calculation with the constraints relationship of the reference points; Finally, get the position and orientation of the object. So the measurement model of monocular vision is constructed. In order to verify the accuracy of measurement model, a plane target using infrared LED as reference points is designed to finish the verification of the measurement method and the corresponding image processing algorithm is studied. And then The monocular vision experimental system is established. Experimental results show that the translational positioning accuracy reaches +/-0.05mm and rotary positioning accuracy reaches +/-0.2o .

  6. 77 FR 13977 - Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources

    Science.gov (United States)

    2012-03-08

    ... AGENCY 40 CFR Part 60 RIN 2060-AH23 Quality Assurance Requirements for Continuous Opacity Monitoring... final rule titled, ``Quality Assurance Requirements for Continuous Opacity Monitoring Systems at... electronically in www.regulations.gov or in hard copy at the Procedure 3--Quality Assurance Requirements for...

  7. 77 FR 8160 - Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources

    Science.gov (United States)

    2012-02-14

    ... AGENCY 40 CFR Part 60 RIN 2060-AH23 Quality Assurance Requirements for Continuous Opacity Monitoring...--Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources Docket, EPA.... Rules establishing quality assurance requirements impose no costs independent from national emission...

  8. 77 FR 18709 - Quality Assurance Requirements for Continuous Opacity Monitoring Systems at Stationary Sources

    Science.gov (United States)

    2012-03-28

    ... AGENCY 40 CFR Part 60 RIN 2060-AH23 Quality Assurance Requirements for Continuous Opacity Monitoring... final rule. SUMMARY: The EPA published a direct final rule titled ``Quality Assurance Requirements for....regulations.gov or in hard copy at the Procedure 3--Quality Assurance Requirements for Continuous Opacity...

  9. 40 CFR Figure 1 to Subpart Qqq of... - Data Summary Sheet for Determination of Average Opacity

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Data Summary Sheet for Determination of.... 63, Subpt. QQQ, Fig. 1 Figure 1 to Subpart QQQ of Part 63—Data Summary Sheet for Determination of Average Opacity Clock time Number of converters blowing Converter aisle activity Average opacity for...

  10. Monocyte development inhibitor PRM-151 decreases corneal myofibroblast generation in rabbits.

    Science.gov (United States)

    Santhiago, M R; Singh, V; Barbosa, F L; Agrawal, V; Wilson, S E

    2011-11-01

    This study investigated whether PRM-151 (Promedior, Inc., Malvern, PA), a recombinant form of human pentraxin-2 (PTX-2, also referred to as serum amyloid P, hSAP), that inhibits differentiation of circulating monocytes into fibrocytes and profibrotic macrophages, could modulate generation of myofibroblasts after opacity-producing corneal injury in rabbits, and, therefore, have potential to reduce or prevent haze after PRK. Nine diopter PRK for myopia was performed with the VISX S4 IR laser. Four groups of 6 animals were treated in masked fashion: Group 1: 30 μl of topical PRM-151 (20 mg/ml) 6 times a day for 5 days; Group 2: 30 μl topical vehicle 6 times a day for 5 days; Group 3: 200 μl sub-conjunctival PRM-151 (total injection of 4 mg) immediately after surgery and every other day until day 8; Group 4: 200 μl sub-conjunctival injections of vehicle according to the same schedule as group 3. At one month after PRK, the animals were euthanized and immunohistochemistry was performed for the myofibroblast marker α-smooth muscle actin (SMA). The density of SMA+ cells/400× field in the central stroma was determined in each cornea. Myofibroblast density at one month after surgery was significantly lower (p = 0.006) after sub-conjunctival PRM-151 treatment (5.8 ± 2.8 cells/400× stromal field) compared to sub-conjunctival vehicle treatment (15.3 ± 2.9 cells/400× stromal field). There was no significant (p = 0.27) decrease in stromal myofibroblasts triggered by topical PRM-151 treatment (11.8 ± 6.6 cells/400× stromal field) compared to the topical vehicle treatment (14.2.8 ± 6.2 cells/400× stromal field). PRM-151 inhibits myofibroblast generation when administered by sub-conjunctival injection, but not when administered topically, after opacity-producing corneal injury. This study provides additional confirmation that bone marrow-derived cells contribute to corneal myofibroblast generation.

  11. Update on pathologic diagnosis of corneal infections and inflammations

    Directory of Open Access Journals (Sweden)

    Geeta K Vemuganti

    2011-01-01

    Full Text Available One of the most frequent types of corneal specimen that we received in our pathology laboratory is an excised corneal tissue following keratoplasty. Several of these cases are due to corneal infections or the sequelae, like corneal scar. Advances in the histological and molecular diagnosis of corneal infections and inflammations have resulted in rapid and accurate diagnosis of the infectious agent and in the overall understanding of the mechanisms in inflammatory diseases of the cornea. This review provides an update of histopathological findings in various corneal infections and inflammations.

  12. Fine-Tuning Two-Particle Interferometry; 2, Opacity Effects

    CERN Document Server

    Tomasik, Boris; Tomasik, Boris; Heinz, Ulrich

    1998-01-01

    We present a model study of single-particle spectra and two-particle Bose-Einstein correlations for opaque sources. We study the transverse mass dependence of the correlation radii R_\\perp, R_\\parallel and R_0 in the YKP parametrization and find a strong sensitivity of the temporal radius parameter R_0^2 to the source opacity. A simple comparison with the published data from 158 A GeV/c Pb+Pb collisions at CERN indicates that the pion source created in these collisions emits particles from the whole reaction volume and is not opaque. For opaque sources we find certain regions of inapplicability of the YKP parametrization which can be avoided by a slightly different parametrization for the correlator. The physical meaning of the modified parameters is briefly discussed.

  13. Galactic cold cores. VI. Dust opacity spectral index

    Science.gov (United States)

    Juvela, M.; Demyk, K.; Doi, Y.; Hughes, A.; Lefèvre, C.; Marshall, D. J.; Meny, C.; Montillaud, J.; Pagani, L.; Paradis, D.; Ristorcelli, I.; Malinen, J.; Montier, L. A.; Paladini, R.; Pelkonen, V.-M.; Rivera-Ingraham, A.

    2015-12-01

    Context. The Galactic Cold Cores project has carried out Herschel photometric observations of 116 fields where the Planck survey has found signs of cold dust emission. The fields contain sources in different environments and different phases of star formation. Previous studies have revealed variations in their dust submillimetre opacity. Aims: The aim is to measure the value of dust opacity spectral index and to understand its variations spatially and with respect to other parameters, such as temperature, column density, and Galactic location. Methods: The dust opacity spectral index β and the dust colour temperature T are derived using Herschel and Planck data. The relation between β and T is examined for the whole sample and inside individual fields. Results: Based on IRAS and Planck data, the fields are characterised by a median colour temperature of 16.1 K and a median opacity spectral index of β = 1.84. The values are not correlated with Galactic longitude. We observe a clear T-β anti-correlation. In Herschel observations, constrained at lower resolution by Planck data, the variations follow the column density structure and βFIR can rise to ~2.2 in individual clumps. The highest values are found in starless clumps. The Planck 217 GHz band shows a systematic excess that is not restricted to cold clumps and is thus consistent with a general flattening of the dust emission spectrum at millimetre wavelengths. When fitted separately below and above 700 μm, the median spectral index values are βFIR ~ 1.91 and β(mm) ~ 1.66. Conclusions: The spectral index changes as a function of column density and wavelength. The comparison of different data sets and the examination of possible error sources show that our results are robust. However, β variations are partly masked by temperature gradients and the changes in the intrinsic grain properties may be even greater. Planck http://www.esa.int/Planck is a project of the European Space Agency - ESA - with instruments

  14. Opacity measurements in shock-generated argon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D.

    1993-07-01

    Dense plasmas having uniform and constant density and temperature are generated by passage of a planar shock wave through gas. The opacity of the plasma is accurately measured versus wavelength by recording the risetime of emitted light. This technique is applicable to a wide variety of species and plasma conditions. Initial experiments in argon have produced plasmas with 2 eV temperatures, 0.004--0.04 g/cm{sup 3} densities, and coupling parameters {Gamma} {approximately}0.3--0.7. Measurements in visible light are compared with calculations using the HOPE code. An interesting peak in the capacity at 400 nm is observed for the first time and is identified with the 4s-5p transition in excited neutral argon atoms.

  15. The hybrid opacity code SCO-RCG: recent developments

    CERN Document Server

    Pain, Jean-Christophe; Porcherot, Quentin; Blenski, Thomas

    2013-01-01

    Absorption and emission spectra of multicharged-ion plasmas contain a huge number of electron configurations and electric-dipolar lines, which can be handled by global methods. However, some transition arrays consist only of a small bunch of lines. For that reason, we developed the hybrid opacity code SCO-RCG combining the (statistical) super-transition-array method and the (detailed) fine-structure calculation (requiring the diagonalization of the Hamiltonian matrix) of atomic structure. In order to decide whether a detailed treatment of lines is necessary and to determine the validity of statistical methods, the code involves criteria taking into account coalescence of lines and porosity (localized absence of lines) in transition arrays. Data required for the calculation of detailed transition arrays (Slater, spin-orbit and dipolar integrals) are provided by the super-configuration code SCO, which takes into account plasma screening effects on wavefunctions. Then, level energies and lines are calculated by ...

  16. Rosseland Mean Opacity of a High-Z Mixture Plasma

    Institute of Scientific and Technical Information of China (English)

    杨家敏; 许琰; 丁耀南; 丁永坤; 江少恩; 郑志坚; 缪文勇

    2003-01-01

    An eight-beam 0.351-μm laser with pulse duration of about 1.0ns and energy of 260 J per beam was injected into a cylindrical cavity to generate intense x-ray radiation on the Shengguang Ⅱ high power laser facility. A mixture foil of gold and gadolinium and a gold foil were attached on portion of a diagnostic hole in the mid-plane of the cavity and ablated by the intense x-ray radiation. The propagating time of the radiation heat wave in the mixture and the pure gold foil were measured with soft-x-ray spectrometer and by adopting space- and timeresolved measurement technology, respectively. The results show that the mixture of gold and gadolinium has higher Rosseland mean opacity than the gold sample in our experiment.

  17. Survival and integration of tissue-engineered corneal stroma in a model of corneal ulcer.

    Science.gov (United States)

    Zhang, Chao; Nie, Xin; Hu, Dan; Liu, Yuan; Deng, Zhihong; Dong, Rui; Zhang, Yongjie; Jin, Yan

    2007-08-01

    Tissue-engineered replacement of diseased or damaged tissue has become a reality for some types of tissue, such as skin and cartilage. Tissue-engineered corneal stroma represents a promising concept to overcome the limitations of cornea replacement with allograft. In this study, porcine cornea was decellularized by a series of extraction methods, and the in vivo biocompatibility of the scaffold was measured subcutaneously in rabbits (n = 8). These were not acutely rejected and no abscesses were observed by hematoxylin and eosin staining at the 8th week, indicating that the scaffolds had good biocompatibility. To investigate the potential value of clinical applications, rabbit stromal keratocytes were implanted onto decellularized scaffolds to fabricate tissue-engineered corneal stroma. Allograft, tissue-engineered corneal stroma, or scaffolds were implanted into a model of corneal ulcer. The survival and reconstruction of corneal transplantation were morphologically evaluated by light and electron microscopy until the 32nd week after implantation. Experiments involving transplantation indicated that the epithelial and stromal defect healed quickly, with improvement in corneal clarity. The integration of the graft was accompanied by neurite ingrowth from the host tissue. By 16 weeks after transplantation, the cornea had gradually regained an intact state similar to that of normal cornea. Our results demonstrate that the tissue-engineered corneal stroma with allogenetic cells is a promising therapeutic method for corneal injury.

  18. Iron Opacity Bump Changes the Stability and Structure of Accretion Disks in Active Galactic Nuclei

    CERN Document Server

    Jiang, Yan-Fei; Stone, James

    2016-01-01

    Accretion disks around supermassive black holes have regions where the Rosseland mean opacity can be much larger than the electron scattering opacity primarily due to the large number of bound-bound transitions in iron. We study the effects of this iron opacity "bump" on the thermal stability and vertical structure of radiation pressure dominated accretion disks, utilizing three dimensional radiation magneto-hydrodynamic simulations in the local shearing box approximation. The simulations self-consistently calculate the heating due to MHD turbulence caused by magneto-rotational instability and radiative cooling by using the radiative transfer module based on a variable Eddington tensor in Athena. For a $5\\times 10^8$ solar mass black hole with $\\sim 3\\%$ of the Eddington luminosity, a model including the iron opacity bump maintains its structure for more than $10$ thermal times without showing significant signs of thermal runaway. In contrast, if only electron scattering and free-free opacity are included as ...

  19. The statistical properties of stars and their dependence on metallicity: the effects of opacity

    CERN Document Server

    Bate, Matthew R

    2014-01-01

    We report the statistical properties of stars and brown dwarfs obtained from four radiation hydrodynamical simulations of star cluster formation that resolve masses down to the opacity limit for fragmentation. The calculations are identical except for their dust and gas opacities. Assuming dust opacity is proportional to metallicity, the calculations span a range of metallicities from 1/100 to 3 times solar, although we emphasise that changing the metallicity has other thermodynamic effects that the calculations do not capture (e.g. on the thermal coupling between gas and dust). All four calculations produce stellar populations whose statistical properties are difficult to distinguish from observed stellar systems, and we find no significant dependence of stellar properties on opacity. The mass functions and properties of multiple stellar systems are consistent with each other. However, we find protostellar mergers are more common with lower opacities. Combining the results from the three calculations with th...

  20. OPACITY MEASUREMENT AND THEORETICAL INVESTIGATION OF HOT SILICON PLASMA

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Gang; Yang, Jiamin; Zhang, Jiyan; Hu, Zhimin; Zhao, Yang; Qing, Bo; Yang, Guohong; Wei, Minxi; Yi, Rongqing; Song, Tianming; Li, Hang; Yuan, Zheng; Lv, Min [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Meng, Xujun; Xu, Yan; Wu, Zeqing; Yan, Jun, E-mail: zhangjiyanzjy@sina.com, E-mail: zhimin.hu@yahoo.com [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2016-01-01

    We report on opacity measurements of a silicon (Si) plasma at a temperature of (72 ± 5) eV and a density of (6.0 ± 1.2) mg cm{sup −3} in the photon energy range of 1790–1880 eV. A 23 μg cm{sup −2} Si foil tamped by 50 μg cm{sup −2} CH layers on each side was heated to a hot-dense plasma state by X-ray radiation emitted from a D-shaped gold cavity that was irradiated by intense lasers. Absorption lines of 1s − 2p transitions of Si xiii to Si ix ions have been measured using point-projection spectroscopy. The transmission spectrum of the silicon plasma was determined by comparing the light passing through the plasma to the light from the same shot passing by the plasma. The density of the Si plasma was determined experimentally by side-on radiography and the temperature was estimated from the radiation flux data. Radiative hydrodynamic simulations were performed to obtain the temporal evolutions of the density and temperature of the Si plasma. The experimentally obtained transmission spectra of the Si sample plasma have been reproduced using a detailed term account model with the local thermodynamic equilibrium approximation. The energy levels, oscillator strengths and photoionization cross-sections used in the calculation were generated by the flexible atomic code. The experimental transmission spectrum was compared with the theoretical calculation and good agreement was found. The present experimental spectrum and theoretical calculation were also compared with the new opacities available in the Los Alamos OPLIB database.

  1. Forward light scatter and visual acuity before and after intrastromal corneal ring segment implantation at different stages of keratoconus.

    Science.gov (United States)

    Puell, María Cinta; Carballo-Álvarez, Jesús

    2016-12-01

    To assess forward light scatter (stray light) before and after intrastromal corneal ring segment (ICRS) implantation at different stages of keratoconus and to examine correlation between postoperative stray light and visual acuity (VA). In 27 eyes of 27 subjects with keratoconus, stray light was determined using the compensation comparison technique before and 6 months after ICRS implantation. Monocular corrected distance VA (CDVA) was measured using a high-contrast logMAR letter chart. Corneal higher-order aberrations (HOAs), contrast sensitivity (CS) and minimum corneal thickness (CT) were also measured. Mean CDVA was 0.42 ± 0.28 preoperatively and 0.24 ± 0.15 logMAR postoperatively (p  0.05) for stage I, 0.13 ± 0.14 (p = 0.013) for stage II and 0.18 ± 0.21 (p = 0.023) for stage III. Significant positive correlation (r = 0.47, p = 0.01) was detected between postoperative stray light and postoperative CDVA such that as stray light increased, CDVA worsened (higher logMAR values). Postoperative stray light was neither associated with HOAs, CS nor minimum CT. Stray light values in these patients with keratoconus were higher than normal preoperatively. In eyes with stage II and III keratoconus, stray light increased 6 months after ICRS placement. Higher postoperative stray light was correlated with a worse visual acuity outcome. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  2. Ultrasound biomicroscopy confirmation of corneal overriding due to improper suturing of full-thickness corneal laceration

    Directory of Open Access Journals (Sweden)

    Murat Kucukevcilioglu

    2014-12-01

    Full Text Available We herein present a case with corneal overriding due to improper suturing of a full-thickness corneal laceration. There was a 2.5-mm difference between horizontal and vertical white-to-white measurements in the cornea. However, slit lamp examination failed to demonstrate the exact architecture of the laceration. Ultrasound biomicroscopy defined the wound edges thoroughly and confirmed the presence of corneal overriding. Six weeks after suture enhancement, the abnormal oval appearance of the cornea was absent and correct apposition of the corneal edges was seen on ultrasound biomicroscopy. Ultrasound biomicroscopy can be used in preoperative surgical planning of cases with complicated corneal lacerations. It can be used to adjust and enhance wound architecture in eyes with penetrating injury.

  3. Measurements of the 492 GHz Atmospheric Opacity at Pampa la Bola and Rio Frio in Northern Chile

    Science.gov (United States)

    Hirota, Tomoya; Yamamoto, Satoshi; Sekimoto, Yutaro; Kohno, Kotaro; Nakai, Naomasa; Kawabe, Ryohei

    1998-02-01

    We have developed a transportable 492 GHz tipping radiometer to measure the atmospheric opacity at potential sites for future ground-based astronomical observations in the submillimeter-wave band. With this radiometer, we measured the atmospheric opacity at two sites in northern Chile, Pampa la Bola (elevation 4800 m) and Rio Frio (elevation 4100 m), each for a few days. The 492 GHz opacity mostly ranged from 0.5 to 1.5 during the measurements. The 220 GHz opacity was also measured at the same time. The 492 GHz opacity correlates well with the 220 GHz opacity, the ratio between the 492 and 220 GHz opacities being 21.2 +/- 0.4. This result supports the standard atmospheric model, and can be used to evaluate the observable fraction of time for submillimeter-wave observations on the basis of the long-term 220 GHz opacity data. } %

  4. Monocular deprivation of Fourier phase information boosts the deprived eye's dominance during interocular competition but not interocular phase combination.

    Science.gov (United States)

    Bai, Jianying; Dong, Xue; He, Sheng; Bao, Min

    2017-06-03

    Ocular dominance has been extensively studied, often with the goal to understand neuroplasticity, which is a key characteristic within the critical period. Recent work on monocular deprivation, however, demonstrates residual neuroplasticity in the adult visual cortex. After deprivation of patterned inputs by monocular patching, the patched eye becomes more dominant. Since patching blocks both the Fourier amplitude and phase information of the input image, it remains unclear whether deprivation of the Fourier phase information alone is able to reshape eye dominance. Here, for the first time, we show that removing of the phase regularity without changing the amplitude spectra of the input image induced a shift of eye dominance toward the deprived eye, but only if the eye dominance was measured with a binocular rivalry task rather than an interocular phase combination task. These different results indicate that the two measurements are supported by different mechanisms. Phase integration requires the fusion of monocular images. The fused percept highly relies on the weights of the phase-sensitive monocular neurons that respond to the two monocular images. However, binocular rivalry reflects the result of direct interocular competition that strongly weights the contour information transmitted along each monocular pathway. Monocular phase deprivation may not change the weights in the integration (fusion) mechanism much, but alters the balance in the rivalry (competition) mechanism. Our work suggests that ocular dominance plasticity may occur at different stages of visual processing, and that homeostatic compensation also occurs for the lack of phase regularity in natural scenes. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. 3.5 Year Monitoring of 225 GHz Opacity at the Summit of Greenland

    Science.gov (United States)

    Matsushita, Satoki; Asada, Keiichi; Martin-Cocher, Pierre L.; Chen, Ming-Tang; Ho, Paul T. P.; Inoue, Makoto; Koch, Patrick M.; Paine, Scott N.; Turner, David D.

    2017-02-01

    We present the 3.5 years monitoring results of 225 GHz opacity at the summit of the Greenland ice sheet (Greenland Summit Camp) at an altitude of 3200 m using a tipping radiometer. We chose this site as our submillimeter telescope (Greenland Telescope) site, because conditions are expected to have low submillimeter opacity and because its location offers favorable baselines to existing submillimeter telescopes for global-scale Very Long Baseline Interferometry. The site shows a clear seasonal variation with the average opacity lower by a factor of two during winter. The 25%, 50%, and 75% quartiles of the 225 GHz opacity during the winter months of November through April are 0.046, 0.060, and 0.080, respectively. For the winter quartiles of 25% and 50%, the Greenland site is about 10%-30% worse than the Atacama Large Millimeter/submillimeter Array (ALMA) or the South Pole sites. Estimated atmospheric transmission spectra in winter season are similar to the ALMA site at lower frequencies (\\lt 450 GHz), which are transparent enough to perform astronomical observations almost all of the winter time with opacities \\lt 0.5, but 10%-25% higher opacities at higher frequencies (\\gt 450 GHz) than those at the ALMA site. This is due to the lower altitude of the Greenland site and the resulting higher line wing opacity from pressure-broadened saturated water lines in addition to higher dry air continuum absorption at higher frequencies. Nevertheless, half of the winter time at the Greenland Summit Camp can be used for astronomical observations at frequencies between 450 GHz and 1000 GHz with opacities \\lt 1.2, and 10% of the time show \\gt 10 % transmittance in the THz (1035 GHz, 1350 GHz, and 1500 GHz) windows. Summer season is good for observations at frequencies lower than 380 GHz. One major advantage of the Greenland Summit Camp site in winter is that there is no diurnal variation due to the polar night condition, and therefore the durations of low-opacity conditions

  6. Changes on the corneal thickness and curvature after orthokeratology

    Science.gov (United States)

    Mitsui, Iwane; Yamada, Yoshiya

    2004-07-01

    To evaluate the corneal thickness and curvature changes after Orthokeratology contact lens wear, using the ORBSCAN II corneal topography system, corneal thickness and corneal curvature were measured on one hundred and twenty eyes of sixty patients before and after wearing the custom rigid gas permeable contact lenses for Orthokeratology. The contact lenses were specially designed for each eye. The subjects wore the orthokeratology lenses for approximately Four hours with their eyes closed. The corneal thickness of the subjects was increased on fifty-five eyes at not only the peripheral zone but also the center of the cornea. The average increase of central and peripheral corneal thickness was 18 micrometer and 22micrometer, respectively. The mean anterior curvature of corneal surface changed 1.25D. The mean posterior curvature of corneal endothelium side changed 0.75D.

  7. Six-month visual outcomes for the correction of presbyopia using a small-aperture corneal inlay: single-site experience

    Directory of Open Access Journals (Sweden)

    Moshirfar M

    2016-11-01

    Full Text Available Majid Moshirfar,1,2 Tyler S Quist,3 David F Skanchy,4 Ryan T Wallace,5 Steven H Linn,1 Phillip C Hoopes Jr1 1Hoopes, Durrie, Rivera Research Center, Hoopes Vision, Draper, 2Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah School of Medicine, Salt Lake City, 3University of Utah School of Medicine, Salt Lake City, UT, 4McGovern Medical School, The University of Texas Health Science Center at Houston, TX, 5Brigham Young University, Provo, UT, USA Objective: The objective of this study was to describe 6-month postoperative efficacy and safety outcomes after monocular KAMRA corneal inlay implantation in emmetropic presbyopic patients. Study design: This study followed a retrospective chart analysis. Setting: This study was performed at Hoopes Vision in Draper, UT, USA. Subjects and methods: Fifty-seven patients met the inclusion criteria of this study and underwent KAMRA corneal inlay implantation following the approval of the United States Food and Drug Association between May 2015 and April 2016 at a single site. Surgery involved femtosecond laser-created corneal pockets of various depths. Efficacy, safety, and patient satisfaction reports were analyzed at 3 and 6 months. Results: At 6 months follow-up, the monocular uncorrected near visual acuity (UNVA was Jaeger (J 4 (20/32, the mean uncorrected distance visual acuity was 20/25, and the mean corrected distance visual acuity was 20/20. At 6 months, 71% of patients with a pocket depth of ≥250 µm had a UNVA of 20/20 or better, whereas only 22% of patients with a shallow pocket depth of <250 µm had a UNVA of 20/20 or better. There was no statistical difference in UNVA at 6 months between virgin eyes and post-LASIK eyes. One patient had an explant and five patients underwent inlay recentration, all of which resulted in improved visual acuity. At 6 months, 72% of patients reported some level of satisfaction, 26% of patients reported being

  8. Acute Corneal Hydrops 3 Years after Intra-corneal Ring Segments and Corneal Collagen Cross-linking

    Science.gov (United States)

    Antonios, Rafic; Dirani, Ali; Fadlallah, Ali; Chelala, Elias; Hamadeh, Adib; Jarade, Elias

    2016-01-01

    This case report describes a 15-year-old male with allergic conjunctivitis and keratoconus, who underwent uneventful intra-corneal ring segment (ICRS) implantation and corneal collagen cross-linking (CXL) in the right eye. During the follow-up periods, the patient was noted to have several episodes of allergic conjunctivitis that were treated accordingly. At the 2 years postoperatively, he presented with another episode of allergic conjunctivitis and progression of keratoconus was suspected on topography. However, the patient was lost to follow-up, until he presented with acute hydrops at 3 years postoperatively. There are no reported cases of acute corneal hydrops in cross-linked corneas. We suspect the young age, allergic conjunctivitis and eye rubbing may be a risk factors associated with possible progression of keratoconus after CXL. Prolonged follow-up and aggressive control of the allergy might be necessary in similar cases. PMID:26957859

  9. [Representation and mathematical analysis of human corneal surface].

    Science.gov (United States)

    Tălu, Stefan; Tălu, Mihai; Giovanzana, Stefano

    2011-01-01

    In the description and analysis of human corneal surface are used various mathematical models based on parametric representations, used in biomechanical studies and 3D solid modeling of the cornea. Mathematical models are important into the biomechanics of the cornea to model the corneal behavior. Corneal biomechanics also has the potential to improve outcomes in refractive surgery. The objective of this paper is to present the most representative mathematical models currently used for modeling of human corneal in optics and biomechanics fields.

  10. Contact lens rehabilitation following repaired corneal perforations

    Directory of Open Access Journals (Sweden)

    Sreenivas V

    2006-03-01

    Full Text Available Abstract Background Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. Method Eyes that had undergone repair for corneal perforating injuries with or without lens aspiration were fitted rigid gas permeable contact lenses. The fitting pattern and the improvement in visual acuity by contact lens over spectacle correction were noted. Results Forty eyes of 40 patients that had undergone surgical repair of posttraumatic corneal perforations were fitted rigid gas permeable contact lenses for visual rehabilitation. Twenty-four eyes (60% required aphakic contact lenses. The best corrected visual acuity (BCVA of ≥ 6/18 in the snellen's acuity chart was seen in 10 (25% eyes with spectacle correction and 37 (92.5% eyes with the use of contact lens (p Conclusion Rigid gas permeable contact lenses are better means of rehabilitation in eyes that have an irregular cornea due to scars caused by perforating corneal injuries.

  11. Corneal Phaeohyphomycosis Caused by Bipolaris hawaiiensis

    Directory of Open Access Journals (Sweden)

    Winai Chaidaroon

    2016-07-01

    Full Text Available Purpose: To report a rare case of keratitis infected by Bipolaris hawaiiensis. Methods: A patient who was diagnosed as fungal keratitis caused by B. hawaiiensis was retrospectively reviewed for history, clinical characteristics, risk factors, laboratory findings, treatments, and outcomes. Results: A 63-year-old man with a history of trauma and saw dust in the left eye presented with a corneal ulcer. Eye examination revealed whitish infiltration with a feathery edge and small brownish deposits in the anterior stroma of the left cornea. Numerous septate hyphal fragments were detected in a corneal specimen, and nucleotide sequence analysis identified B. hawaiiensis. Treatment was started with 5% natamycin eyedrops and oral itraconazole. Subsequently, a corneal plaque developed which did not respond to medication and debridement. The patient underwent therapeutic penetrating keratoplasty. Conclusions: B. hawaiiensis is a rare cause of corneal phaeohyphomycosis. A brownish pigmented infiltration is an important diagnostic clue, however microbiologic studies are required to obtain a definite diagnosis. Although antifungal medication and debridement are the mainstay of most corneal fungal infection, therapeutic penetrating keratoplasty can prevent morbidity related to this fungal infection.

  12. Corneal Phaeohyphomycosis Caused by Bipolaris hawaiiensis

    Science.gov (United States)

    Chaidaroon, Winai; Supalaset, Sumet; Tananuvat, Napaporn; Vanittanakom, Nongnuch

    2016-01-01

    Purpose To report a rare case of keratitis infected by Bipolaris hawaiiensis. Methods A patient who was diagnosed as fungal keratitis caused by B. hawaiiensis was retrospectively reviewed for history, clinical characteristics, risk factors, laboratory findings, treatments, and outcomes. Results A 63-year-old man with a history of trauma and saw dust in the left eye presented with a corneal ulcer. Eye examination revealed whitish infiltration with a feathery edge and small brownish deposits in the anterior stroma of the left cornea. Numerous septate hyphal fragments were detected in a corneal specimen, and nucleotide sequence analysis identified B. hawaiiensis. Treatment was started with 5% natamycin eyedrops and oral itraconazole. Subsequently, a corneal plaque developed which did not respond to medication and debridement. The patient underwent therapeutic penetrating keratoplasty. Conclusions B. hawaiiensis is a rare cause of corneal phaeohyphomycosis. A brownish pigmented infiltration is an important diagnostic clue, however microbiologic studies are required to obtain a definite diagnosis. Although antifungal medication and debridement are the mainstay of most corneal fungal infection, therapeutic penetrating keratoplasty can prevent morbidity related to this fungal infection. PMID:27721785

  13. Corneal trephination with the femtosecond laser.

    Science.gov (United States)

    Meltendorf, Christian; Schroeter, Jan; Bug, Reinhold; Kohnen, Thomas; Deller, Thomas

    2006-10-01

    To evaluate the feasibility and cut quality of corneal trephination in human donor corneal tissue with the femtosecond laser. Twelve human corneoscleral discs were inserted in an artificial anterior chamber. After corneal thickness measurement and tonometry, the cornea was mounted on a femtosecond laser (FEMTEC; 20/10 Perfect Vision, Heidelberg, Germany) through a contact lens (patient interface). Trephination was performed with diameters of 7.0, 7.5, 8.0, and 8.5 mm in 3 corneas each. The corneal button was removed from the corneoscleral disc in 2 of the 3 corneas in each case. The cut was not manipulated in the remaining corneas to enable histologic detection of possible tissue bridges. The cut edges were macroscopically and light-microscopically examined for quality. Corneal buttons and corneoscleral discs could be separated by blunt dissection in all cases. Tissue bridges were more common in thicker edematous corneas than in thinner ones. Both the macro- and microscopic examination disclosed smooth rectilinear cut margins with a perpendicular cut edge. This feasibility study shows that the femtosecond laser enables sufficient trephination of human donor corneas.

  14. Corneal reconstruction by stem cells and bioengineering

    Directory of Open Access Journals (Sweden)

    Arjamaa O

    2012-09-01

    Full Text Available Olli ArjamaaDepartment of Biology, University of Turku, Turku, FinlandAbstract: Almost 300 million people are visually impaired worldwide due to various eye diseases such as cataracts, glaucoma, age-related macular degeneration, diabetic retinopathy, and corneal diseases. Notably, ten million people are blind because of severe ocular surface diseases and the majority of cases occur in developing countries. Blinding ocular surface diseases have, however, become treatable by grafting of surface layers, or by full-thickness transplantation of the cornea. As the demand for human corneal tissue for surface reconstruction and transplantation far exceeds the supply, methods are being developed to supplement tissue donation. Xenotransplantation of the cornea or cells from genetically modified pigs may become one of the solutions. Transplantation of limbal stem cells within tissue biopsies, to restore the transparency of the cornea is another remarkable method, which has shown its potential in several clinical studies. The combination of stem cell technology and engineering of biocompatible tissue equivalent, still at preclinical stage, has shown us how synthetic corneal tissue is able to guide cultured corneal stromal stem cells of human origin, to become native-like stroma, the most important layer of the cornea. These findings give hope for a large-quantity production of biomaterial for corneal reconstruction. As such, clinical ophthalmologists should become more familiar with the methods of laboratory science.Keywords: eye, grafting, keratoplasty, xenotransplantation, cell reservoir, biocompatible tissue equivalent

  15. The impact of enhanced iron opacity on massive star pulsations: updated instability strips

    Science.gov (United States)

    Moravveji, Ehsan

    2016-01-01

    Recently, Bailey et al. made a direct measurement of the iron opacity at the physical conditions of the solar tachocline. They found that the wavelength-integrated iron opacity is roughly 75 per cent higher than what the Opacity Project (OP) and OPAL models predict. Here, we compute new opacity tables with enhanced iron and nickel contributions to the Rosseland mean opacity by 75 per cent each, and compute three dense MESA grids of evolutionary models for Galactic O- and B-type stars covering from 2.5 to 25 M⊙ from zero-age main sequence (ZAMS) until Teff = 10 000 K after the core hydrogen exhaustion. We carry out non-adiabatic mode stability analysis with GYRE, and update the extension of the instability strips of heat-driven p- and g-mode pulsators, and the hybrid slowly pulsating B (SPB) - β Cep stars. We compare the position of two confirmed late O-type β Cep and eight confirmed hybrid B-type pulsators with the new instability domains, and justify that ˜75 per cent enhancement, only in iron opacity, is sufficient to consistently reproduce the observed position of these stars on the log Teff versus log g plane. We propose that this improvement in opacities be incorporated in the input physics of new stellar models.

  16. Detailed investigations on radiative opacity and emissivity of tin plasmas in the extreme-ultraviolet region.

    Science.gov (United States)

    Zeng, Jiaolong; Gao, Cheng; Yuan, Jianmin

    2010-08-01

    Radiative opacity and emissivity of tin plasmas at average ionization degree of about 10 was investigated in detail by using a fully relativistic detailed level accounting approach, in which main physical effects on the opacity were carefully taken into account. Among these physical effects, configuration interaction, in particular core-valence electron correlations, plays an important role on the determination of accurate atomic data required in the calculation of opacity. It results in a strong narrowing of lines from all transition arrays and strong absorption is located in a narrow wavelength region of 12.5-14 nm for Sn plasmas. Using a complete accurate atomic data, we investigated the opacity of Sn plasmas at a variety of physical condition. Among the respective ions of Xe6+-Xe15+ , Xe10+ has the largest absorption cross section at 13.5 nm, while the favorable physical condition for maximal absorption at 13.5 nm do not mean that Xe10+ has the largest fraction. Comparison with other theoretical results showed that a complete set of consistent accurate atomic data, which lacks very much, is essential to predict accurate opacity. Our atomic model is useful and can be applied to interpret opacity experiments. Further benchmark experiments are urgently needed to clarify the physical effects on the opacity of Sn plasmas.

  17. Using xRage to Model Heat Flow for Experiments to Measure Opacities in HED Plasmas

    Science.gov (United States)

    Elgin, L.; Vandervort, R.; Keiter, P.; Drake, R. P.; Mussack, K.; Orban, C.

    2015-11-01

    We are developing a NIF proposal to measure opacities of C, N and O at temperatures and densities relevant to the base of the solar convection zone. Our proposed experiments would provide the first opacity measurements for these elements within this HED regime. A critical feature of our experimental platform is a super-sonic radiation front propagating within the targets. Under these conditions, density remains constant across the radiation front for a couple nanoseconds, enabling a window during which the opacities of the hot and cold target may be measured simultaneously. Afterwards, hydrodynamic effects create temperature and density gradients, which would obfuscate analysis of opacity data. We are using xRage to simulate heat flow within our targets in order to estimate the time scale over which temperature and density gradients evolve. These simulations will better inform our target design and diagnostic requirements. If successful, our experiments could yield the data necessary to validate existing opacity models or provide physical insights to inform the development of new opacity models. Accurate opacity models are essential to the understanding of radiation transport within HED systems, with applications ranging from astrophysics to ICF. U.S. Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant #DE-NA0001840. Los Alamos National Laboratory, LA-UR-15-25490.

  18. Analysis of the horizontal corneal diameter, central corneal thickness, and axial length in premature infants

    Directory of Open Access Journals (Sweden)

    Ozdemir Ozdemir

    2014-08-01

    Full Text Available Purpose: To determine the horizontal corneal diameter, central corneal thickness, and axial length in premature infants. Methods: Infants with a birth weight of less than 2,500 g or with a gestation period of less than 36 weeks were included in the study. Infants with retinopathy of prematurity (ROP were allocated to Group 1 (n=138, while those without ROP were allocated to Group 2 (n=236. All infants underwent a complete ophthalmologic examination, including corneal diameter measurements, pachymetry, biometry, and fundoscopy. Between-group comparisons of horizontal corneal diameter, central corneal thickness, and axial lengths were performed. Independent sample t-tests were used for statistical analysis. Results: Data was obtained from 374 eyes of 187 infants (102 female, 85 male. The mean gestational age at birth was 30.7 ± 2.7 weeks (range 25-36 weeks, the mean birth weight was 1,514 ± 533.3 g (range 750-1,970 g, and the mean postmenstrual age at examination was 40.0 ± 4.8 weeks. The mean gestational age and the mean birth weight of Group 1 were statistically lower than Group 2 (p0.05. Conclusions: The presence of ROP in premature infants does not alter the horizontal corneal diameter, central corneal thickness, or axial length.

  19. Cirurgia monocular para esotropias de grande ângulo: um novo paradigma Monocular surgery for large-angle esotropias: a new paradigm

    Directory of Open Access Journals (Sweden)

    Edmilson Gigante

    2009-02-01

    Full Text Available OBJETIVO: Demonstrar a viabilidade da cirurgia monocular no tratamento das esotropias de grande ângulo, praticando-se amplos recuos do reto medial (6 a 10 mm e grandes ressecções do reto lateral (8 a 10 mm. MÉTODOS: Foram operados, com anestesia geral e sem reajustes per ou pósoperatórios, 46 pacientes com esotropias de 50δ ou mais, relativamente comitantes. Os métodos utilizados para refratometria, medida da acuidade visual e do ângulo de desvio, foram os, tradicionalmente, utilizados em estrabologia. No pós-operatório, além das medidas na posição primária do olhar, foi feita uma avaliação da motilidade do olho operado, em adução e em abdução. RESULTADOS: Foram considerados quatro grupos de estudo, correspondendo a quatro períodos de tempo: uma semana, seis meses, dois anos e quatro a sete anos. Os resultados para o ângulo de desvio pós-cirúrgico foram compatíveis com os da literatura em geral e mantiveram-se estáveis ao longo do tempo. A motilidade do olho operado apresentou pequena limitação em adução e nenhuma em abdução, contrariando o encontrado na literatura estrabológica. Comparando os resultados de adultos com os de crianças e de amblíopes com não amblíopes, não foram encontradas diferenças estatisticamente significativas entre eles. CONCLUSÃO:Em face dos resultados encontrados, entende-se ser possível afirmar que a cirurgia monocular de recuo-ressecção pode ser considerada opção viável para o tratamento das esotropias de grande ângulo, tanto para adultos quanto para crianças, bem como para amblíopes e não amblíopes.PURPOSE: To demonstrate the feasibility of monocular surgery in the treatment of large-angle esotropias through large recessions of the medial rectus (6 to 10 mm and large resections of the lateral rectus (8 to 10 mm. METHODS: 46 patients were submitted to surgery. They had esotropias of 50Δor more that were relatively comitant. The patients were operated under general

  20. 21 CFR 886.1450 - Corneal radius measuring device.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Corneal radius measuring device. 886.1450 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1450 Corneal radius measuring device. (a) Identification. A corneal radius measuring device is an AC-powered device intended to...

  1. Systematic measurements of opacity dependence on temperature, density, and atomic number at stellar interior conditions

    Science.gov (United States)

    Bailey, James; Nagayama, T.; Loisel, G. P.; Rochau, G. A.; Blancard, C.; Colgan, J.; Cosse, Ph.; Faussurier, G.; Fontes, C. J.; Golovkin, I.; Hansen, S. B.; Iglesias, C. A.; Kilcrease, D. P.; Macfarlane, J. J.; Mancini, R. C.; Nahar, S. N.; Orban, C.; Pradhan, A. K.; Sherrill, M.; Wilson, B. G.; Pain, J. C.; Gilleron, F.

    2016-10-01

    Model predictions for iron opacity are notably different from measurements performed at conditions similar to the boundary between the solar radiation and convection zone. New measurements at the Sandia Z facility with chromium, iron, and nickel are providing a systematic study of how opacity changes with temperature, density, and atomic number. These measurements help further evaluate possibilities for experiment errors and help constrain hypotheses for opacity model refinements. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

  2. Theoretical Study of the Opacity for Mixture Materials at High Temperatures

    Institute of Scientific and Technical Information of China (English)

    颜君; 吴泽清; 逄锦桥; 邱玉波

    2002-01-01

    Using a detailed configuration accounting model with term structures treated by the unresolved transition array model, we have extensively investigated the opacities of mixt ure materials. For plasmas at the temperat ure of 250eV and density of 1 g/cm3, our calculated Rosseland mean opacities are in good agreement with other theoretical results. A high increase in the Rosseland mean opacity to 2944 cm2/g is achieved for a multi-element mixture compared to the value of 1729 cm2/g for pure gold. Various mixtures at other plasma conditions are also studied.

  3. Corneal nerve microstructure in Parkinson's disease.

    Science.gov (United States)

    Misra, Stuti L; Kersten, Hannah M; Roxburgh, Richard H; Danesh-Meyer, Helen V; McGhee, Charles N J

    2017-03-03

    Ocular surface changes and blink abnormalities are well-established in Parkinson's disease. Blink rate may be influenced by corneal sub-basal nerve density, however, this relationship has not yet been investigated in Parkinson's disease. This case-control study examined the ocular surface in patients with moderately severe Parkinson's disease, including confocal microscopy of the cornea. Fifteen patients with moderately severe Parkinson's disease (modified Hoehn and Yahr grade 3 or 4) and fifteen control participants were recruited. Ophthalmic assessment included slit-lamp examination, blink rate assessment, central corneal aesthesiometry and in vivo corneal confocal microscopy. The effect of disease laterality was also investigated. Of the 15 patients with Parkinson's disease, ten were male and the mean age was 65.5±8.6years. The corneal sub-basal nerve plexus density was markedly reduced in patients with Parkinson's disease (7.56±2.4mm/mm(2)) compared with controls (15.91±2.6mm/mm(2)) (pParkinson's disease (0.79±1.2mBAR) and the control group (0.26±0.35mBAR), p=0.12. Sub-basal nerve density was not significantly different between the eye ipsilateral to the side of the body with most-severe motor symptoms, and the contralateral eye. There was a significant positive correlation between ACE-R scores and sub-basal corneal nerve density (R(2)=0.66, p=0.02). This is the first study to report a significant reduction in corneal sub-basal nerve density in Parkinson's disease and demonstrate an association with cognitive dysfunction. These results provide further evidence to support the involvement of the peripheral nervous system in Parkinson's disease, previously thought to be a central nervous system disorder.

  4. Normal corneal endothelial cell density in Nigerians

    Directory of Open Access Journals (Sweden)

    Ewete T

    2016-03-01

    Full Text Available Temitope Ewete,1 Efeoghene Uchenna Ani,2 Adegboyega Sunday Alabi1 1MeCure Eye Center, Lagos, 2Department of Ophthalmology, University of Port Harcourt, Port Harcourt, Nigeria Aim: The aim of the study was to describe the corneal endothelial cell density of adults at the MeCure Eye Center and to determine the relationship between age, sex, and corneal endothelial cell density. Methods: This study was a retrospective study looking at those records of individuals who had undergone specular microscopy or corneal endothelial cell count measurement at the MeCure Eye Center. Results: The endothelial cell characteristics of 359 healthy eyes of 201 volunteers were studied. The mean corneal endothelial cell density (MCD was 2,610.26±371.87 cells/mm2 (range, 1,484–3,571 cells/mm2. The MCD decreased from 2,860.70 cells/mm2 in the 20–30-year age group to 2,493.06 cells/mm2 in the >70-year age group, and there was a statistically significant relationship between age and MCD with a P-value of <0.001. There was no statistically significant correlation between sex and corneal endothelial cell density (P=0.45. Conclusion: This study shows that endothelial cell density in Nigerian eyes is less than that reported in the Japanese, American, and Chinese eyes, and is comparable to that seen in Indian and Malaysian eyes. Keywords: corneal, endothelial cell density, Nigerian

  5. Learning Depth from Single Monocular Images Using Deep Convolutional Neural Fields.

    Science.gov (United States)

    Liu, Fayao; Shen, Chunhua; Lin, Guosheng; Reid, Ian

    2016-10-01

    In this article, we tackle the problem of depth estimation from single monocular images. Compared with depth estimation using multiple images such as stereo depth perception, depth from monocular images is much more challenging. Prior work typically focuses on exploiting geometric priors or additional sources of information, most using hand-crafted features. Recently, there is mounting evidence that features from deep convolutional neural networks (CNN) set new records for various vision applications. On the other hand, considering the continuous characteristic of the depth values, depth estimation can be naturally formulated as a continuous conditional random field (CRF) learning problem. Therefore, here we present a deep convolutional neural field model for estimating depths from single monocular images, aiming to jointly explore the capacity of deep CNN and continuous CRF. In particular, we propose a deep structured learning scheme which learns the unary and pairwise potentials of continuous CRF in a unified deep CNN framework. We then further propose an equally effective model based on fully convolutional networks and a novel superpixel pooling method, which is about 10 times faster, to speedup the patch-wise convolutions in the deep model. With this more efficient model, we are able to design deeper networks to pursue better performance. Our proposed method can be used for depth estimation of general scenes with no geometric priors nor any extra information injected. In our case, the integral of the partition function can be calculated in a closed form such that we can exactly solve the log-likelihood maximization. Moreover, solving the inference problem for predicting depths of a test image is highly efficient as closed-form solutions exist. Experiments on both indoor and outdoor scene datasets demonstrate that the proposed method outperforms state-of-the-art depth estimation approaches.

  6. More clinical observations on migraine associated with monocular visual symptoms in an Indian population

    Directory of Open Access Journals (Sweden)

    Vishal Jogi

    2016-01-01

    Full Text Available Context: Retinal migraine (RM is considered as one of the rare causes of transient monocular visual loss (TMVL and has not been studied in Indian population. Objectives: The study aims to analyze the clinical and investigational profile of patients with RM. Materials and Methods: This is an observational prospective analysis of 12 cases of TMVL fulfilling the International Classification of Headache Disorders-2nd edition (ICHD-II criteria of RM examined in Neurology and Ophthalmology Outpatient Department (OPD of Postgraduate Institute of Medical Education and Research (PGIMER, Chandigarh from July 2011 to October 2012. Results: Most patients presented in 3 rd and 4 th decade with equal sex distribution. Seventy-five percent had antecedent migraine without aura (MoA and 25% had migraine with Aura (MA. Headache was ipsilateral to visual symptoms in 67% and bilateral in 33%. TMVL preceded headache onset in 58% and occurred during headache episode in 42%. Visual symptoms were predominantly negative except in one patient who had positive followed by negative symptoms. Duration of visual symptoms was variable ranging from 30 s to 45 min. None of the patient had permanent monocular vision loss. Three patients had episodes of TMVL without headache in addition to the symptom constellation defining RM. Most of the tests done to rule out alternative causes were normal. Magnetic resonance imaging (MRI brain showed nonspecific white matter changes in one patient. Visual-evoked potential (VEP showed prolonged P100 latencies in two cases. Patent foramen ovale was detected in one patient. Conclusions: RM is a definite subtype of migraine and should remain in the ICHD classification. It should be kept as one of the differential diagnosis of transient monocular vision loss. We propose existence of "acephalgic RM" which may respond to migraine prophylaxis.

  7. Mixed quotation: The grammar of apparently transparent opacity

    Directory of Open Access Journals (Sweden)

    Emar Maier

    2014-05-01

    Full Text Available The phenomenon of mixed quotation exhibits clear signs of both the apparent transparency of compositional language use and the opacity of pure quotation. I argue that the interpretation of a mixed quotation in- volves the resolution of a metalinguistic presupposition. The leading idea behind my proposal is that a mixed-quoted expression, say, “has an anomalous feature”, means what x referred to with the words ‘has an anomalous feature’. To understand how this solves the paradox, I set up a precise grammatical framework, explicitly connecting various levels of linguistic analysis: phonological forms, categorial syntax, and a dynamic picture of the semantics–pragmatics interface. In this framework I formalize and evaluate a presuppositional account of mixed quotation. Finally, I address the phenomenon of unquotation and argue that it is an essential ingredient for an elegant and empirically adequate analysis of mixed quotation in natural language. http://dx.doi.org/10.3765/sp.7.7 BibTeX info

  8. P2-1: Visual Short-Term Memory Lacks Sensitivity to Stereoscopic Depth Changes but is Much Sensitive to Monocular Depth Changes

    Directory of Open Access Journals (Sweden)

    Hae-In Kang

    2012-10-01

    Full Text Available Depth from both binocular disparity and monocular depth cues presumably is one of most salient features that would characterize a variety of visual objects in our daily life. Therefore it is plausible to expect that human vision should be good at perceiving objects' depth change arising from binocular disparities and monocular pictorial cues. However, what if the estimated depth needs to be remembered in visual short-term memory (VSTM rather than just perceived? In a series of experiments, we asked participants to remember depth of items in an array at the beginning of each trial. A set of test items followed after the memory array, and the participants were asked to report if one of the items in the test array have changed its depth from the remembered items or not. The items would differ from each other in three different depth conditions: (1 stereoscopic depth under binocular disparity manipulations, (2 monocular depth under pictorial cue manipulations, and (3 both stereoscopic and monocular depth. The accuracy of detecting depth change was substantially higher in the monocular condition than in the binocular condition, and the accuracy in the both-depth condition was moderately improved compared to the monocular condition. These results indicate that VSTM benefits more from monocular depth than stereoscopic depth, and further suggests that storage of depth information into VSTM would require both binocular and monocular information for its optimal memory performance.

  9. Corneal collagen crosslinking for keratoconus. A review

    Directory of Open Access Journals (Sweden)

    M. M. Bikbov

    2014-10-01

    Full Text Available Photochemical crosslinking is widely applied in ophthalmology. Its biochemical effect is due to the release of singlet oxygen that promotes anaerobic photochemical reaction. Keratoconus is one of the most common corneal ectasia affecting 1 in 250 to 250 000 persons. Currently, the rate of iatrogenic ectasia following eximer laser refractive surgery increases due to biomechanical weakening of the cornea. Morphologically and biochemically, ectasia is characterized by corneal layers thinning, contact between the stroma and epithelium resulting from Bowman’s membrane rupture, chromatin fragmentation in keratocyte nuclei, phagocytosis, abnormal staining and arrangement of collagen fibers, enzyme system disorders, and keratocyte apoptosis. In corneal ectasia, altered enzymatic processes result in the synthesis of abnormal collagen. Collagen packing is determined by the activity of various extracellular matrix enzymes which bind amines and aldehydes of collagen fiber amino acids. In the late stage, morphological changes of Descemet’s membrane (i.e., rupture and detachment develop. Abnormal hexagonal-shaped keratocytes and their apoptosis are the signs of endothelial dystrophy. The lack of analogs in domestic ophthalmology encouraged the scientists of Ufa Eye Research Institute to develop a device for corneal collagen crosslinking. The parameters of ultraviolet (i.e., wavelength, exposure time, power to achieve the desired effect were identified. The specifics of some photosensitizers in the course of the procedure were studied. UFalink, a device for UV irradiation of cornea, and photosensitizer Dextralink were developed and adopted. Due to the high risk of endothelial damage, this treatment is contraindicated in severe keratoconus (CCT less than 400 microns. Major effects of corneal collagen crosslinking are the following: Young’s modulus (modulus of elasticity increase by 328.9 % (on average, temperature tolerance increase by 5

  10. Corneal collagen crosslinking for keratoconus. A review

    Directory of Open Access Journals (Sweden)

    M. M. Bikbov

    2014-01-01

    Full Text Available Photochemical crosslinking is widely applied in ophthalmology. Its biochemical effect is due to the release of singlet oxygen that promotes anaerobic photochemical reaction. Keratoconus is one of the most common corneal ectasia affecting 1 in 250 to 250 000 persons. Currently, the rate of iatrogenic ectasia following eximer laser refractive surgery increases due to biomechanical weakening of the cornea. Morphologically and biochemically, ectasia is characterized by corneal layers thinning, contact between the stroma and epithelium resulting from Bowman’s membrane rupture, chromatin fragmentation in keratocyte nuclei, phagocytosis, abnormal staining and arrangement of collagen fibers, enzyme system disorders, and keratocyte apoptosis. In corneal ectasia, altered enzymatic processes result in the synthesis of abnormal collagen. Collagen packing is determined by the activity of various extracellular matrix enzymes which bind amines and aldehydes of collagen fiber amino acids. In the late stage, morphological changes of Descemet’s membrane (i.e., rupture and detachment develop. Abnormal hexagonal-shaped keratocytes and their apoptosis are the signs of endothelial dystrophy. The lack of analogs in domestic ophthalmology encouraged the scientists of Ufa Eye Research Institute to develop a device for corneal collagen crosslinking. The parameters of ultraviolet (i.e., wavelength, exposure time, power to achieve the desired effect were identified. The specifics of some photosensitizers in the course of the procedure were studied. UFalink, a device for UV irradiation of cornea, and photosensitizer Dextralink were developed and adopted. Due to the high risk of endothelial damage, this treatment is contraindicated in severe keratoconus (CCT less than 400 microns. Major effects of corneal collagen crosslinking are the following: Young’s modulus (modulus of elasticity increase by 328.9 % (on average, temperature tolerance increase by 5

  11. Corneal Topographic Analysis in Patients with Cataract

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    We studied the corneal curvature of 161 eyes in 101 patients, aged from 50 to 80 years (mean: 63 years), with senile cataract using the Topographic Modeling System (IMS) preoperatively. The results revealed that mean surface asymmetry index (SAD was 0. 36 and mean surface regularity index (SRI) 0. 79. Simulated keratometry reading (Sim K) was 44. 46 D, and 43. 56 D. Minimun K reading was 42. 60 D. The same patterns of corneal topography in both eyes were 50% in 60 patients who had binocular examination....

  12. Bessel Function Model for Corneal Topography

    CERN Document Server

    Okrasiński, Wojciech

    2011-01-01

    In this paper we consider a new nonlinear mathematical model for corneal topography formulated as two-point boudary value problem. We derive it from first physical principles and provide some mathematical analysis. The existence and uniqeness theorems are proved as well as various estimates on exact solution. At the end we fit the simplified model based on Modified Bessel Function of the First Kind with the real corneal data consisting of matrix of 123x123 points and obtain an error of order of 1%.

  13. Colletotrichum graminicola: a new corneal pathogen.

    Science.gov (United States)

    Ritterband, D C; Shah, M; Seedor, J A

    1997-05-01

    We report the first case of an ocular infection with the fungus Colletotrichum graminicola causing keratitis in a 27-year-old man. Twenty-four months after a postoperative course complicated by recurrent fungal keratitis requiring two penetrating keratoplasties, two anterior chamber washouts, a conjunctival flap, and medical treatment with topical natamycin, intracameral amphotericin B, and oral fluconazole. The patient has shown no signs of fungal recurrence despite a failed corneal graft. C. graminicola is a new corneal pathogen and should be included in the differential diagnosis of mycotic keratitis.

  14. Research on inhibition of corneal neovascularization

    Directory of Open Access Journals (Sweden)

    Zhang-Hui Yang

    2015-12-01

    Full Text Available Corneal transparency is the basis of the normal physiological functions.However, corneal neovascularization(CNVmay occur in the infection, mechanical and chemical injury or under other pathological conditions,which make the cornea lose original transparency and severe visual impairment. In recent years, along with the development of immunology, molecular biology, biochemistry and other disciplines, there is more in-depth understanding on the CNV, and clinical treatment of CNV has made new breakthroughs. This article provides an overview of the inhibition of CNV.

  15. Neural correlates of monocular and binocular depth cues based on natural images: a LORETA analysis.

    Science.gov (United States)

    Fischmeister, Florian Ph S; Bauer, Herbert

    2006-10-01

    Functional imaging studies investigating perception of depth rely solely on one type of depth cue based on non-natural stimulus material. To overcome these limitations and to provide a more realistic and complete set of depth cues natural stereoscopic images were used in this study. Using slow cortical potentials and source localization we aimed to identify the neural correlates of monocular and binocular depth cues. This study confirms and extends functional imaging studies, showing that natural images provide a good, reliable, and more realistic alternative to artificial stimuli, and demonstrates the possibility to separate the processing of different depth cues.

  16. Three dimensional monocular human motion analysis in end-effector space

    DEFF Research Database (Denmark)

    Hauberg, Søren; Lapuyade, Jerome; Engell-Nørregård, Morten Pol

    2009-01-01

    In this paper, we present a novel approach to three dimensional human motion estimation from monocular video data. We employ a particle filter to perform the motion estimation. The novelty of the method lies in the choice of state space for the particle filter. Using a non-linear inverse kinemati...... solver allows us to perform the filtering in end-effector space. This effectively reduces the dimensionality of the state space while still allowing for the estimation of a large set of motions. Preliminary experiments with the strategy show good results compared to a full-pose tracker....

  17. Effect of ophthalmic filter thickness on predicted monocular dichromatic luminance and chromaticity discrimination.

    Science.gov (United States)

    Richer, S P; Little, A C; Adams, A J

    1984-11-01

    The majority of ophthalmic filters, whether they be in the form of spectacles or contact lenses, are absorbance type filters. Although color vision researchers routinely provide spectrophotometric transmission profiles of filters, filter thickness is rarely specified. In this paper, colorimetric tools and volume color theory are used to show that the color of a filter as well as its physical properties are altered dramatically by changes in thickness. The effect of changes in X-Chrom filter thickness on predicted monocular dichromatic luminance and chromaticity discrimination is presented.

  18. Estimating 3D positions and velocities of projectiles from monocular views.

    Science.gov (United States)

    Ribnick, Evan; Atev, Stefan; Papanikolopoulos, Nikolaos P

    2009-05-01

    In this paper, we consider the problem of localizing a projectile in 3D based on its apparent motion in a stationary monocular view. A thorough theoretical analysis is developed, from which we establish the minimum conditions for the existence of a unique solution. The theoretical results obtained have important implications for applications involving projectile motion. A robust, nonlinear optimization-based formulation is proposed, and the use of a local optimization method is justified by detailed examination of the local convexity structure of the cost function. The potential of this approach is validated by experimental results.

  19. Monocular feature tracker for low-cost stereo vision control of an autonomous guided vehicle (AGV)

    Science.gov (United States)

    Pearson, Chris M.; Probert, Penelope J.

    1994-02-01

    We describe a monocular feature tracker (MFT), the first stage of a low cost stereoscopic vision system for use on an autonomous guided vehicle (AGV) in an indoor environment. The system does not require artificial markings or other beacons, but relies upon accurate knowledge of the AGV motion. Linear array cameras (LAC) are used to reduce the data and processing bandwidths. The limited information given by LAC require modelling of the expected features. We model an obstacle as a vertical line segment touching the floor, and can distinguish between these obstacles and most other clutter in an image sequence. Detection of these obstacles is sufficient information for local AGV navigation.

  20. Granular Corneal Dystrophy Manifesting after Radial Keratotomy

    Directory of Open Access Journals (Sweden)

    Sepehr Feizi

    2008-12-01

    Full Text Available

    PURPOSE: To report manifestation of granular corneal dystrophy after radial keratotomy (RK. CASE REPORT: A 32-year-old man presented with white radial lines in both corneas. He had undergone uncomplicated RK in both eyes 8 years ago. Preoperative refraction had been OD: -3.5 -0.75@180 and OS: -3.0 -0.5@175. Uncorrected visual acuity was OD: 8/10 and OS: 7/10; best corrected visual acuity was 9/10 in both eyes with OD: -0.5 -0.5@60 and OS: -0.75 -0.5@80. Slit lamp examination revealed discrete well-demarcated whitish lesions with clear intervening stroma in the central anterior cornea consistent with granular dystrophy. Similar opacities were present within the RK incisions. CONCLUSION: Granular dystrophy deposits may appear within RK incisions besides other previously reported locations.

  1. Reversible corneal toxicity of retained intracameral Perfluoro-n-octane

    Directory of Open Access Journals (Sweden)

    Saad S Alharbi

    2016-01-01

    Full Text Available A 58-year-old female presented with intracameral retained perfluoro-n-octane (PFO following previous retinal reattachment surgery. After 4 years of follow-up without related sequelae, the patient complained of a gradual decrease in vision secondary to corneal edema with whitish corneal precipitate inferiorly corresponding to the area of retained PFO. Three weeks after anterior chamber washout, corneal edema resolved and the patient obtained 20/40 visual acuity. Even though PFO considered to have a relatively good safety profile, early anterior chamber washout may prevent corneal toxicity and avoid later persistent corneal decompensation.

  2. Current status of accelerated corneal cross-linking

    Directory of Open Access Journals (Sweden)

    Michael Mrochen

    2013-01-01

    Full Text Available Corneal cross-linking with riboflavin is a technique to stabilize or reduce corneal ectasia, in diseases such as keratoconus and post-laser-assisted in situ keratomileusis (LASIK ectasia. There is an interest by patient as well as clinicians to reduce the overall treatment time. Especially, the introduction of corneal cross-linking in combination with corneal laser surgery demands a shorter treatment time to assure a sufficient patient flow. The principles and techniques of accelerated corneal cross-linking is discussed.

  3. Infants' ability to respond to depth from the retinal size of human faces: comparing monocular and binocular preferential-looking.

    Science.gov (United States)

    Tsuruhara, Aki; Corrow, Sherryse; Kanazawa, So; Yamaguchi, Masami K; Yonas, Albert

    2014-11-01

    To examine sensitivity to pictorial depth cues in young infants (4 and 5 months-of-age), we compared monocular and binocular preferential looking to a display on which two faces were equidistantly presented and one was larger than the other, depicting depth from the size of human faces. Because human faces vary little in size, the correlation between retinal size and distance can provide depth information. As a result, adults perceive a larger face as closer than a smaller one. Although binocular information for depth provided information that the faces in our display were equidistant, under monocular viewing, no such information was provided. Rather, the size of the faces indicated that one was closer than the other. Infants are known to look longer at apparently closer objects. Therefore, we hypothesized that infants would look longer at a larger face in the monocular than in the binocular condition if they perceived depth from the size of human faces. Because the displays were identical in the two conditions, any difference in looking-behavior between monocular and binocular viewing indicated sensitivity to depth information. Results showed that 5-month-old infants preferred the larger, apparently closer, face in the monocular condition compared to the binocular condition when static displays were presented. In addition, when presented with a dynamic display, 4-month-old infants showed a stronger 'closer' preference in the monocular condition compared to the binocular condition. This was not the case when the faces were inverted. These results suggest that even 4-month-old infants respond to depth information from a depth cue that may require learning, the size of faces. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Infants’ ability to respond to depth from the retinal size of human faces: Comparing monocular and binocular preferential-looking

    Science.gov (United States)

    Tsuruhara, Aki; Corrow, Sherryse; Kanazawa, So; Yamaguchi, Masami K.; Yonas, Albert

    2014-01-01

    To examine sensitivity to pictorial depth cues in young infants (4 and 5 months-of-age), we compared monocular and binocular preferential looking to a display on which two faces were equidistantly presented and one was larger than the other, depicting depth from the size of human faces. Because human faces vary little in size, the correlation between retinal size and distance can provide depth information. As a result, adults perceive a larger face as closer than a smaller one. Although binocular information for depth provided information that the faces in our display were equidistant, under monocular viewing, no such information was provided. Rather, the size of the faces indicated that one was closer than the other. Infants are known to look longer at apparently closer objects. Therefore, we hypothesized that infants would look longer at a larger face in the monocular than in the binocular condition if they perceived depth from the size of human faces. Because the displays were identical in the two conditions, any difference in looking-behavior between monocular and binocular viewing indicated sensitivity to depth information. Results showed that 5-month-old infants preferred the larger, apparently closer, face in the monocular condition compared to the binocular condition when static displays were presented. In addition, when presented with a dynamic display, 4-month-old infants showed a stronger ‘closer’ preference in the monocular condition compared to the binocular condition. This was not the case when the faces were inverted. These results suggest that even 4-month-old infants respond to depth information from a depth cue that may require learning, the size of faces. PMID:25113916

  5. Large enhancement in high-energy photoionization of Fe XVII and missing continuum plasma opacity

    CERN Document Server

    Nahar, Sultana N

    2016-01-01

    Aimed at solving the outstanding problem of solar opacity, and radiation transport plasma models in general, we report substantial photoabsorption in the high-energy regime due to atomic core photo-excitations not heretofore considered. In extensive R-Matrix calculations of unprecedented complexity for an important iron ion Fe xvii (Fe$^{16+}$), with a wave function expansion of 99 Fe xviii (Fe$^{17+}$) LS core states from $n \\leq 4$ complexes (equivalent to 218 fine structure levels), we find: i) up to orders of magnitude enhancement in background photoionization cross sections, in addition to strongly peaked photo-excitation-of-core resonances not considered in current opacity models, and ii) demonstrate convergence with respect to successive core excitations. The resulting increase in the monochromatic continuum, and 35% in the Rosseland Mean Opacity, are compared with the "higher-than-predicted" iron opacity measured at the Sandia Z-pinch fusion device at solar interior conditions.

  6. Corneal invasion of ocular surface squamous neoplasia after clear corneal phacoemulsification: in vivo confocal microscopy analysis.

    Science.gov (United States)

    Balestrazzi, Angelo; Martone, Gianluca; Pichierri, Patrizia; Tosi, Gian Marco; Caporossi, Aldo

    2008-06-01

    We describe an unusual case of ocular surface squamous neoplasia (OSSN) that occurred in a male patient after superonasal clear corneal phacoemulsification with extensive papillomatous corneal invasion near a side port. The features of the macroscopic invasion of the corneal superficial layers were analyzed by in vivo confocal analysis using the Heidelberg Retina Tomograph II. After OSSN was diagnosed, topical mitomycin-C 0.02% eyedrops were prescribed 4 times a day in a cyclic manner (3 cycles of 1 week on drops followed by 1 week off). After 1 month (second cycle), the natural visual acuity was 20/20, the corneal epithelium had healed completely, and the limbal lesion had regressed markedly. The patient remained asymptomatic without recurrence during a 6-month follow-up.

  7. Corneal heat scar caused by photodynamic therapy performed through an implanted corneal inlay.

    Science.gov (United States)

    Mita, Mariko; Kanamori, Tomomi; Tomita, Minoru

    2013-11-01

    A 60-year-old man had a combination of laser in situ keratomileusis and Kamra corneal inlay implantation to correct presbyopia. Although the outcome was favorable postoperatively, central serous chorioretinopathy was observed in the left eye along with a decrease in the uncorrected (UDVA) and corrected (CDVA) distance visual acuities and the corrected near visual acuity (CNVA). Photodynamic therapy (PDT) was later performed in a university hospital. After PDT, the patient experienced a decline in the visual acuity and came to our clinic a month after the PDT. Degeneration and a scar were observed at the location of the inlay due to the heat and burning. Flattening of the corneal topography was also observed where the corneal scar was located, along with a significant decrease in CDVA in the left eye. Prior to any surgery in which the corneal inlay is an impediment, surgeons should take advantage of the reversibility of the Kamra inlay by explanting the inlay.

  8. The Effect of Corneal Epithelium on Corneal Curvature in Patients with Keratoconus.

    Science.gov (United States)

    Akcay, Emine Kalkan; Uysal, Betul Seher; Sarac, Ozge; Ugurlu, Nagehan; Yulek, Fatma; Cagil, Nurullah; Aslan, Nabi

    2015-01-01

    To investigate the effects of corneal epithelium on corneal curvature in patients with keratoconus. This is a prospective, nonrandomized study. Fifty-nine eyes of 47 patients diagnosed as keratoconus and for whom corneal collagen crosslinking (CXL) was recruited in this study. This study is a single-center clinical trial. Pregnancy, lactation, connective tissue disease, corneal thickness below 350 μm, severe dry eyes, or scar of corneal surgery were exclusion criteria. Before and during CXL procedure after removing the corneal epithelium, maximum values of corneal apical curvature, simulated keratometry 1 (Sim-K1), simulated keratometry 2 (Sim-K2), temporal and inferior curvature values, all of which are 1.5 mm from the corneal center, were calculated. These values before and after removal of epithelium were compared statistically. Mean age of patients was 23.30 ± 5.5 (12-38) years. Twenty-eight (59%) were male while 19 (41%) were female. Mean values measured before and after removing the corneal epithelium were: apical curvature; 59.19 ± 7.2 (47.06-82.40) diopter (D) and 61.70 ± 8.8 (49.19-92.66) D (p = 0.001), SimK1; 47.57 ± 4.3 (39.14-64.57) D and 48.23 ± 4.3 (41.89-66.70) D (p = 0.001), SimK2; 52.04 ± 5.3 (43.56-69.34) D and 53.34 ± 5.6 (43.73-70.89) D (p = 0.001), inferior curvature; 53,85 ± 5.2 (43.47-76.56) D and 55.05 ± 5.8 (44.56-81.93) D (p = 0.002), temporal curvature 49.49 ± 5.1 (41.50-71.03) D and 51.53 ± 5.4 (41.58-73.34) D (p = 0.001), respectively. In keratoconus patients during CXL treatment, after removing the corneal epithelium, more steepness is detected in the curvature of the steeper area of the cornea. When evaluating patients with keratoconus, the masking effect of corneal epithelium on values of curvature should be taken into consideration.

  9. Radiative opacity of plasmas studied by detailed term (level) accounting approaches

    Institute of Scientific and Technical Information of China (English)

    ZENG Jiao-long; JIN Feng-tao; YUAN Jian-min

    2006-01-01

    Detailed term and level accounting (DTA and DLA) schemes have been developed to calculate the spectrally resolved and Rosseland and Planck mean opacities of plasmas in local thermodynamic equilibrium.Various physical effects,such as configuration interaction effect (including core-valence electron correlations effect and relativistic effect),detailed line width effect (including the line saturation effect),etc.,on the opacity of plasmas have been investigated in detail.Some of these physical effects are less capable or even impossible to be taken into account by statistical models such as unresolved transition arrays,super-transitionarray or average atom models.Our detailed model can obtain accurate opacity of plasmas.Using this model,we have systematically investigated the radiative opacities of low,medium and high-Z plasmas under different conditions of temperature and density.For example,for aluminum plasma,in the X-ray region,we demonstrated the effects of autoionization resonance broadening on the opacity for the first time.Furthermore,the relativistic effects play an important role on the opacity as well.Our results are in good agreement with other theoretical ones although better agreement can be obtained after the effects of autoionization resonance broadening and relativity have been considered.Our results also show that the modelling of the opacity is very complicated,since too many physical effects influence the accuracy of opacity.``For medium and high-Z plasmas,however,there are systematic discrepancies unexplained so far between the theoretical and experimental opacities.Here,the theoretical opacities are mainly obtained by statistical models.To clarify the discrepaneies,efforts from both sides are needed.From the viewpoint of theory,however,a DLA method,in which various physical effects can be taken into account,should be useful in resolving the difference.Taking gold plasma as an example,we studied in detail the effects of core-valence electron

  10. Congenital Unilateral Corneal Anaesthesia with Microphthalmos: A Case Report

    Directory of Open Access Journals (Sweden)

    George Voyatzis

    2012-01-01

    Full Text Available Congenital corneal anaesthesia (CCA is an uncommon condition difficult to diagnose. We report the case of a 20-month-old boy who presented with unilateral congenital corneal anaesthesia. The child was referred with a persistent corneal epithelial defect, unresponsive to symptomatic local treatment for over 10 months. Intensive topical treatment and strict corneal protection led to quick corneal healing. Congenital corneal anaesthesia occurs either alone or in association with neurological diseases or systemic congenital abnormalities. It is important to search for corneal anaesthesia in children with chronic ulcerations of the cornea and self-inflicted injuries. Early diagnosis and treatment are important due to the risk of poor visual prognosis. Management of CCA should aim for the prevention of epithelial defects and is a life-long process.

  11. Corneal Higher Order Aberrations in Granular, Lattice and Macular Corneal Dystrophies

    Science.gov (United States)

    Yagi-Yaguchi, Yukari; Yamaguchi, Takefumi; Okuyama, Yumi; Satake, Yoshiyuki; Tsubota, Kazuo; Shimazaki, Jun

    2016-01-01

    Purpose To evaluate the corneal higher-order aberrations (HOAs) in granular, lattice and macular corneal dystrophies. Methods This retrospective study includes consecutive patients who were diagnosed as granular corneal dystrophy type2 (GCD2; 121 eyes), lattice corneal dystrophies type 1, type 3A (LCDI; 20 eyes, LCDIIIA; 32 eyes) and macular corneal dystrophies (MCD; 13 eyes), and 18 healthy control eyes. Corneal HOAs were calculated using anterior segment optical coherence tomography, and the correlations between HOAs and visual acuity were analyzed. Results HOAs of the total cornea within 4 mm diameter were significantly larger in GCD2 (0.17 ± 0.35 μm), in LCDI (0.33 ± 0.27), LCDIIIA (0.61 ± 1.56) and in MCD (0.23 ± 0.18), compared with healthy controls (0.09 ± 0.02μm, all P GCD2 (0.32 ± 0.48), in LCDI (0.60 ± 0.46), LCDIIIA (0.83 ± 2.29) and in MCD (0.44 ± 0.24), compared with healthy controls (0.19 ± 0.06, all P GCD2, there was no significant correlation between logMAR and HOAs (r = 0.113, P = 0.227). In MCD, LCDI and LCDIIIA, logMAR was positively significantly correlated with HOAs (r = 0.620 and P = 0.028, r = 0.587 and P = 0.007, r = 0.614 and P < 0.001, respectively). Conclusions Increased HOAs occur in eyes with corneal dystrophies, especially in eye with LCD and MCD. Larger amount corneal HOAs are associated with poorer visual acuity in patients with LCD and MCD. PMID:27536778

  12. Computational Design of Short Pulse Laser Driven Iron Opacity Measurements at Stellar-Relevant Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madison E. [Univ. of Florida, Gainesville, FL (United States)

    2017-05-20

    Opacity is a critical parameter in the simulation of radiation transport in systems such as inertial con nement fusion capsules and stars. The resolution of current disagreements between solar models and helioseismological observations would bene t from experimental validation of theoretical opacity models. Overall, short pulse laser heated iron experiments reaching stellar-relevant conditions have been designed with consideration of minimizing tamper emission and optical depth effects while meeting plasma condition and x-ray emission goals.

  13. Purification and partial characterization of the opacity-associated proteins of Neisseria gonorrhoeae

    OpenAIRE

    1984-01-01

    Gonococci, grown on agar, frequently give rise to opaque colonies. This opacity phenotype is associated with the presence of one or more outer membrane proteins of approximately 28,000 mol weight. These proteins are included within a class of proteins named proteins II. A method is described to isolate and purify the opacity-associated proteins from Neisseria gonorrhoeae. This method uses high concentrations of calcium and a zwitterionic detergent at pH 4.0. Under these conditions proteins II...

  14. The relationship between central corneal thickness and corneal curvature in adult Nigerians

    Directory of Open Access Journals (Sweden)

    E. Iyamu

    2011-12-01

    Full Text Available Purpose: The aim of this study was to provide average values for central corneal thickness (CCT and corneal curvature (CC and also to determine a regression model for the relationship between CCT and CC in adult Nigerians without glaucoma.Methods: A total of 95 subjects consisting of 56 males and 39 females aged between 20 and 69 years with mean age of 47.1 ± 14.1 years were recruited for the study. Central corneal thickness was measured by ultrasound pachymetry (SW-1000P ultrasound pachymeter, Tianjin Suowei Electronic Technology, China and corneal curvature was measured by keratometry (Bausch & Lomb keratometer H-135A, USA.Results: The average values of 550.1 ± 33.1µm and 43.0 ± 1.1 D were obtained for CCT and CC respectively. CCT significantly correlated with age (p=0.01, and the regression model predicts a decrease of 6.0 µm in CCT per decade. No significant association was found between CC and age (p=0.56. Also, no significant association was found between CCT and CC (p=0.07. Female subjects had significantly steeper corneas than their male counterparts.Conclusion: Central corneal thickness decreases with increasing age. Neither CCT nor age appear to be significantly correlated with corneal curvature. (S Afr Optom 2011 70(1 44-50

  15. CORNEAL STROMAL THINNING: A RARE CORNEAL COMPLICATION AFTER BARE SCL ERA PTERYG I UM EXCISION TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Sulaiman Abdul

    2015-06-01

    Full Text Available INTRODUCTION : Bare sclera technique without using any anti - mitotic drugs are commonly employed in rural population. Corneal dellen formation and recurrence of pterygium are more common in these cases. But the corneal complication like stromal thinning, necrosis of corne a and sclera are not common. The corneal epithelium is a highly differentiated cell type that is self - renewing. Also corneal epithelium is important for the stromal replacement in the situations like chemical, thermal burns, ocular surgery like pterygium s urgery. Interference with status of stem cell replacement and as a consequent to it, stromal thinning is occurring in the pterygium surgery. P atient 1: A 68 yr s. old male patient underwent pterygium surgery ( B aresclera excision technique. After 30 days he developed corneal thinning with the punched out partial stromal loss without perforation or descmetocele or scleral thinning. Patient 2: A 60yr s. old male patient underwent pterygium surgery 2months back, he developed same type of corneal thinning. Both P atients were treated with tear drops and improved. CONCLUSION : The stromal thinning in these two cases is may be due to chemical factors like collagenase which might have been released from the traumatised conjunctival epithelial cells causing thinning wit hout replacement of stroma by limbal stem cells.

  16. Quantitative proteomic analysis of mice corneal tissues reveals angiogenesis-related proteins involved in corneal neovascularization.

    Science.gov (United States)

    Shen, Minqian; Tao, Yimin; Feng, Yifan; Liu, Xing; Yuan, Fei; Zhou, Hu

    2016-07-01

    Corneal neovascularization (CNV) was induced in Balb/c mice by alkali burns in the central area of the cornea with a diameter of 2.5mm. After fourteen days, the cornea from one eye was collected for histological staining for CNV examination, while the cornea from the other eye of the same mouse was harvested for proteomic analysis. The label-free quantitative proteomic approach was applied to analyze five normal corneal tissues (normal group mice n=5) and five corresponding neovascularized corneal tissues (model group mice n=5). A total of 2124 proteins were identified, and 1682 proteins were quantified from these corneal tissues. Among these quantified proteins, 290 proteins were significantly changed between normal and alkali burned corneal tissues. Of these significantly changed proteins, 35 were reported or predicted as angiogenesis-related proteins. Then, these 35 proteins were analyzed using Ingenuity Pathway Analysis Software, resulting in 26 proteins enriched and connected to each other in the protein-protein interaction network, such as Lcn-2, αB-crystallin and Serpinf1 (PEDF). These three significantly changed proteins were selected for further Western blotting validation. Consistent with the quantitative proteomic results, Western blotting showed that Lcn-2 and αB-crystallin were significantly up-regulated in CNV model, while PEDF was down-regulated. This study provided increased understanding of angiogenesis-related proteins involved in corneal vascular development, which will be useful in the ophthalmic clinic of specifically target angiogenesis.

  17. A brief history of corneal transplantation: From ancient to modern

    Directory of Open Access Journals (Sweden)

    Alexandra X Crawford

    2013-01-01

    Full Text Available This review highlights many of the fundamental concepts and events in the development of corneal transplantation - from ancient times to modern. Tales of eye, limb, and even heart transplantation appear in ancient and medieval texts; however, in the scientific sense, the original concepts of corneal surgery date back to the Greek physician Galen (130-200 AD. Although proposals to provide improved corneal clarity by surgical interventions, including keratoprostheses, were better developed by the 17 th and 18 th centuries, true scientific and surgical experimentation in this field did not begin until the 19 th century. Indeed, the success of contemporary corneal transplantation is largely the result of a culmination of pivotal ideas, experimentation, and perseverance by inspired individuals over the last 200 years. Franz Reisinger initiated experimental animal corneal transplantation in 1818, coining the term "keratoplasty". Subsequently, Wilhelmus Thorne created the term corneal transplant and 3 years later Samuel Bigger, 1837, reported successful corneal transplantation in a gazelle. The first recorded therapeutic corneal xenograft on a human was reported shortly thereafter in 1838-unsurprisingly this was unsuccessful. Further progress in corneal transplantation was significantly hindered by limited understanding of antiseptic principles, anesthesiology, surgical technique, and immunology. There ensued an extremely prolonged period of debate and experimentation upon the utility of animal compared to human tissue, and lamellar versus penetrating keratoplasty. Indeed, the first successful human corneal transplant was not performed by Eduard Zirm until 1905. Since that first successful corneal transplant, innumerable ophthalmologists have contributed to the development and refinement of corneal transplantation aided by the development of surgical microscopes, refined suture materials, the development of eye banks, and the introduction of

  18. A brief history of corneal transplantation: From ancient to modern.

    Science.gov (United States)

    Crawford, Alexandra Z; Patel, Dipika V; McGhee, Charles Nj

    2013-09-01

    This review highlights many of the fundamental concepts and events in the development of corneal transplantation - from ancient times to modern. Tales of eye, limb, and even heart transplantation appear in ancient and medieval texts; however, in the scientific sense, the original concepts of corneal surgery date back to the Greek physician Galen (130-200 AD). Although proposals to provide improved corneal clarity by surgical interventions, including keratoprostheses, were better developed by the 17(th) and 18(th) centuries, true scientific and surgical experimentation in this field did not begin until the 19(th) century. Indeed, the success of contemporary corneal transplantation is largely the result of a culmination of pivotal ideas, experimentation, and perseverance by inspired individuals over the last 200 years. Franz Reisinger initiated experimental animal corneal transplantation in 1818, coining the term "keratoplasty". Subsequently, Wilhelmus Thorne created the term corneal transplant and 3 years later Samuel Bigger, 1837, reported successful corneal transplantation in a gazelle. The first recorded therapeutic corneal xenograft on a human was reported shortly thereafter in 1838-unsurprisingly this was unsuccessful. Further progress in corneal transplantation was significantly hindered by limited understanding of antiseptic principles, anesthesiology, surgical technique, and immunology. There ensued an extremely prolonged period of debate and experimentation upon the utility of animal compared to human tissue, and lamellar versus penetrating keratoplasty. Indeed, the first successful human corneal transplant was not performed by Eduard Zirm until 1905. Since that first successful corneal transplant, innumerable ophthalmologists have contributed to the development and refinement of corneal transplantation aided by the development of surgical microscopes, refined suture materials, the development of eye banks, and the introduction of corticosteroids. Recent

  19. OPAC AS DOCUMENT RETRIEVAL TOOL: A CASE STUDY OF THE UNIVERSITY OF KASHMIR

    Directory of Open Access Journals (Sweden)

    Uzma Qadri, Research Scholar,

    2012-01-01

    Full Text Available The application of the information and communication technology has changed the entireenvironment of the library including cataloguing. Today, a number of libraries are providingOnline Public Access Cataloguing service to their users to find out their documents and theAllama Iqbal Library, University of Kashmir isn’t an exception. The main purpose of the study isto measure the faculty wise use of OPAC by the P G students of University of Kashmir. Toaccomplish the purpose of the study, survey method was adopted and questionnaire was used asdata collection tool. The questionnaire was distributed among 260 students selecting 10 students from each department in the month of May 2012. However, only 241 students returned the filled questionnaire with response rate of 92.69 %. The results revealed that 60% of the respondents use OPAC to search the library collection whereas 40% don’t use it at all. The students who use OPAC cite many features like time saving; fast response; remote access etc. and the students don’t use OPAC mostly due to awareness problem. This study found that most of the student learn to operate OPAC from themselves followed by friends/colleagues and library staff. The students search the library material mostly through subject, author and title approach. At the end, the fruitful suggestions are provided for greater use of OPAC.

  20. How the machine ‘thinks’: Understanding opacity in machine learning algorithms

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    Jenna Burrell

    2016-01-01

    Full Text Available This article considers the issue of opacity as a problem for socially consequential mechanisms of classification and ranking, such as spam filters, credit card fraud detection, search engines, news trends, market segmentation and advertising, insurance or loan qualification, and credit scoring. These mechanisms of classification all frequently rely on computational algorithms, and in many cases on machine learning algorithms to do this work. In this article, I draw a distinction between three forms of opacity: (1 opacity as intentional corporate or state secrecy, (2 opacity as technical illiteracy, and (3 an opacity that arises from the characteristics of machine learning algorithms and the scale required to apply them usefully. The analysis in this article gets inside the algorithms themselves. I cite existing literatures in computer science, known industry practices (as they are publicly presented, and do some testing and manipulation of code as a form of lightweight code audit. I argue that recognizing the distinct forms of opacity that may be coming into play in a given application is a key to determining which of a variety of technical and non-technical solutions could help to prevent harm.

  1. Coagulation and Fragmentation in molecular clouds. II. The opacity of the dust aggregate size distribution

    CERN Document Server

    Ormel, C W; Tielens, A G G M; Dominik, C; Paszun, D

    2011-01-01

    The dust size distribution in molecular clouds can be strongly affected by ice-mantle formation and (subsequent) grain coagulation. Following previous work where the dust size distribution has been calculated from a state-of-the art collision model for dust aggregates that involves both coagulation and fragmentation (Paper I), the corresponding opacities are presented in this study. The opacities are calculated by applying the effective medium theory assuming that the dust aggregates are a mix of 0.1{\\mu}m silicate and graphite grains and vacuum. In particular, we explore how the coagulation affects the near-IR opacities and the opacity in the 9.7{\\mu}m silicate feature. We find that as dust aggregates grow to {\\mu}m-sizes both the near-IR color excess and the opacity in the 9.7 {\\mu}m feature increases. Despite their coagulation, porous aggregates help to prolong the presence of the 9.7{\\mu}m feature. We find that the ratio between the opacity in the silicate feature and the near-IR color excess becomes lowe...

  2. How the machine ‘thinks’: Understanding opacity in machine learning algorithms

    Directory of Open Access Journals (Sweden)

    Jenna Burrell

    2016-01-01

    Full Text Available This article considers the issue of opacity as a problem for socially consequential mechanisms of classification and ranking, such as spam filters, credit card fraud detection, search engines, news trends, market segmentation and advertising, insurance or loan qualification, and credit scoring. These mechanisms of classification all frequently rely on computational algorithms, and in many cases on machine learning algorithms to do this work. In this article, I draw a distinction between three forms of opacity: (1 opacity as intentional corporate or state secrecy, (2 opacity as technical illiteracy, and (3 an opacity that arises from the characteristics of machine learning algorithms and the scale required to apply them usefully. The analysis in this article gets inside the algorithms themselves. I cite existing literatures in computer science, known industry practices (as they are publicly presented, and do some testing and manipulation of code as a form of lightweight code audit. I argue that recognizing the distinct forms of opacity that may be coming into play in a given application is a key to determining which of a variety of technical and non-technical solutions could help to prevent harm.

  3. Corneal injuries from liquid detergent pods.

    Science.gov (United States)

    Gray, Michael E; West, Constance E

    2014-10-01

    Laundry and dishwasher detergent "pods" were introduced to the United States market in 2010 and are sold by several manufacturers. They represent a high percentage of household cleaning product exposure in the United Kingdom. We present a consecutive case series of 10 children seen in a 9-month period with corneal injuries from exposure to liquid detergent pods.

  4. Evaluation and Treatment of Perioperative Corneal Abrasions

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    Kira L. Segal

    2014-01-01

    Full Text Available Purpose. To evaluate perioperative risk factors for corneal abrasion (CA and to determine current care for perioperative CA in a tertiary care setting. Methods. Hospital-based, cross-sectional study. In Operating Room and Post-Anesthesia Care Units patients, a comparison of cases and controls was evaluated to elucidate risk factors, time to treatment, and most common treatments prescribed for corneal abrasions. Results. 86 cases of corneal abrasion and 89 controls were identified from the 78,542 surgical procedures performed over 2 years. Statistically significant risk factors were age (P=0.0037, general anesthesia (P<0.001, greater average estimated blood loss (P<0.001, eyes taped during surgery (P<0.001, prone position (P<0.001, trendelenburg position (P<0.001, and supplemental oxygen en route to and in the Post-Anesthesia Care Units (P<0.001. Average time to complaint was 129 minutes. 94% of cases had an inpatient ophthalmology consult, with an average time to consult of 164 minutes. The most common treatment was artificial tears alone (40%, followed by combination treatment of antibiotic ointment and artificial tears (35.3%. Conclusions. Trendelenburg positioning is a novel risk factor for CA. Diagnosis and treatment of perioperative corneal abrasions by an ophthalmologist typically require three hours in the tertiary care setting.

  5. Serological profile of candidates for corneal donation

    Directory of Open Access Journals (Sweden)

    Adroaldo Lunardelli

    2014-10-01

    Full Text Available Objetive: The purpose of this study is to map the serological profile of candidates to corneal donation at Irmandade Santa Casa de Misericórdia de Porto Alegre, identifying the percentage of disposal by serology and the marker involved. Methods: There have been analised – retrospectively – the results of serology of all corneal donors, made between the period of 1st january 2006 and 31st december 2012. Data analised were related to age, gender and the results of serology pertinent to viral markers (HBsAg, anti-HBc, anti-HCV and anti-HIV, these, determined by immunosorbent tests (ELISA. Results: In the period of the study, there were 2476 corneal donors at the institution, with a major incidence on the male gender, on an average of 58.7 years old. 23% of retention because of serological unfitness was also identified, that is, 570 samples were non-negative to any of the used tests. The marker anti- HBc was the most prevalent on the studied population, followed by the Hepatitis C virus (HCV and by the Human Immunodeficiency Virus (HIV. Conclusion: From the data found through this study, it is essential to have the participation of an efficient service on the serological evaluation of the candidates to corneal donation, once the security of the receptor must be taken into consideration in a population of donors with 23% of unfitness prevalence, in which the most prevalent marker is the one of Hepatits B.

  6. Peptide Amphiphiles in Corneal Tissue Engineering

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    Martina Miotto

    2015-08-01

    Full Text Available The increasing interest in effort towards creating alternative therapies have led to exciting breakthroughs in the attempt to bio-fabricate and engineer live tissues. This has been particularly evident in the development of new approaches applied to reconstruct corneal tissue. The need for tissue-engineered corneas is largely a response to the shortage of donor tissue and the lack of suitable alternative biological scaffolds preventing the treatment of millions of blind people worldwide. This review is focused on recent developments in corneal tissue engineering, specifically on the use of self-assembling peptide amphiphiles for this purpose. Recently, peptide amphiphiles have generated great interest as therapeutic molecules, both in vitro and in vivo. Here we introduce this rapidly developing field, and examine innovative applications of peptide amphiphiles to create natural bio-prosthetic corneal tissue in vitro. The advantages of peptide amphiphiles over other biomaterials, namely their wide range of functions and applications, versatility, and transferability are also discussed to better understand how these fascinating molecules can help solve current challenges in corneal regeneration.

  7. Corneal topography measurements for biometric applications

    Science.gov (United States)

    Lewis, Nathan D.

    The term biometrics is used to describe the process of analyzing biological and behavioral traits that are unique to an individual in order to confirm or determine his or her identity. Many biometric modalities are currently being researched and implemented including, fingerprints, hand and facial geometry, iris recognition, vein structure recognition, gait, voice recognition, etc... This project explores the possibility of using corneal topography measurements as a trait for biometric identification. Two new corneal topographers were developed for this study. The first was designed to function as an operator-free device that will allow a user to approach the device and have his or her corneal topography measured. Human subject topography data were collected with this device and compared to measurements made with the commercially available Keratron Piccolo topographer (Optikon, Rome, Italy). A third topographer that departs from the standard Placido disk technology allows for arbitrary pattern illumination through the use of LCD monitors. This topographer was built and tested to be used in future research studies. Topography data was collected from 59 subjects and modeled using Zernike polynomials, which provide for a simple method of compressing topography data and comparing one topographical measurement with a database for biometric identification. The data were analyzed to determine the biometric error rates associated with corneal topography measurements. Reasonably accurate results, between three to eight percent simultaneous false match and false non-match rates, were achieved.

  8. Aspergillus terreus recovered from a corneal scraping.

    Science.gov (United States)

    Campbell, Suzanne

    2014-01-01

    A 52 year old, healthy male presented to his optometrist complaining of redness and irritation in the right eye. A foreign body was removed from the eye. The patient was started on ophthalmic solutions of vigamox and systane. At 48 hours, the patient reported increased redness, limited vision, and yellow discharge from the eye. The patient was referred to an ophthalmologist for further evaluation. Physical assessment revealed a superlative central infiltrate (extreme, centrally located injury that had permeated the cornea), diffuse corneal haze, and edema with a 3- to 4+ conjunctival injection and a 1 millimeter hypopyon (an effusion of pus into the anterior chamber of the eye). Corneal scrapings were collected for aerobic and anaerobic bacterial and fungal cultures. The patient was then prescribed. vancomycin, tobramycin, and natamycin ophthalmic eyedrops. On day three, fungal culture results indicated possible fungal forms seen. On day 12, results from the fungal culture of the corneal scraping revealed the causative agent to be Aspergillus terreus. Voriconazole eyedrops were added to the treatment regimen and continued for 10 weeks. The physician order for a fungal culture as well as laboratory data providing the final identification of Aspergillus terreus and laboratory comments indicating an elevated minimum inhibitory concentration (MIC) (> 2 microg/mL) to amphotericin B is associated with treatment failure positively impacted the patient outcome. After completion of the treatment regimen, a photo-therapeutic keratectomy (PTK) was performed in an attempt to remove the dense corneal scarring caused by the fungal infection.

  9. [Purulent corneal ulcers: etiology, pathogenesis, classification].

    Science.gov (United States)

    Kasparova, Evg A

    2015-01-01

    Advanced purulent corneal ulcer, as well as abscess, is a serious vision-threatening condition notable for its fulminant course and possible loss of the eye due to endophthalmitis. Its leading causes, pathogenesis, and classifications are described and analyzed in this paper.

  10. Change in corneal curvature induced by surgery

    NARCIS (Netherlands)

    G. van Rij (Gabriel)

    1987-01-01

    textabstractThe first section deals with the mechanisms by which sutures, incisions and intracorneal contact lenses produce a change in corneal curvature. To clarify the mechanisms by which incisions and sutures produce astigmatism, we made incisions and placed sutures in the corneoscleral limbus of

  11. Autophagy in granular corneal dystrophy type 2.

    Science.gov (United States)

    Choi, Seung-Il; Kim, Eung Kweon

    2016-03-01

    Autophagy is a lysosomal degradative process that is essential for cellular homeostasis and metabolic stress adaptation. Defective autophagy is involved in the pathogenesis of many diseases including granular corneal dystrophy type 2 (GCD2). GCD2 is an autosomal dominant disorder caused by substitution of histidine for arginine at codon 124 (R124H) in the transforming growth factor β-induced gene (TGFBI) on chromosome 5q31. Transforming growth factor β-induced protein (TGFBIp) is degraded by autophagy, but mutant-TGFBIp accumulates in autophagosomes and/or lysosomes, despite significant activation of basal autophagy, in GCD2 corneal fibroblasts. Furthermore, inhibition of autophagy induces cell death of GCD2 corneal fibroblasts through active caspase-3. As there is currently no pharmacological treatment for GCD2, development of novel therapies is required. A potential strategy for preventing cytoplasmic accumulation of mutant-TGFBIp in GCD2 corneal fibroblasts is to enhance mutant-TGFBIp degradation. This could be achieved by activation of the autophagic pathway. Here, we will consider the role and the potential therapeutic benefits of autophagy in GCD2, with focus on TGFBIp degradation, in light of the recently established role of autophagy in protein degradation.

  12. Polysaccharide coating of human corneal endothelium

    DEFF Research Database (Denmark)

    Schroder, H D; Sperling, S

    1977-01-01

    Electron microscopy revealed the presence of a 600-1500 A thick layer of polysaccharide on the surface of human corneal endothelial cells. The surface layer was visualized by combined fixation and staining in a mixture of ruthenium red and osmium tetroxide. The coating material was stable...

  13. Traumatic wound dehiscence after corneal keratoplasty

    Directory of Open Access Journals (Sweden)

    Patrick Frensel Tzelikis

    2015-10-01

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

  14. Past and present of corneal refractive surgery

    DEFF Research Database (Denmark)

    Vestergaard, Anders Højslet

    Surgical correction of refractive errors is becoming increasingly popular. In the 1990s, the excimer laser revolutionized the field of corneal refractive surgery with PRK and LASIK, and lately refractive lenticule extraction (ReLEx) of intracorneal tissue, using only a femtosecond laser, has become...

  15. Corneal Transplantation in Disease Affecting Only One Eye: Does It Make a Difference to Habitual Binocular Viewing?

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    Praveen K Bandela

    Full Text Available Clarity of the transplanted tissue and restoration of visual acuity are the two primary metrics for evaluating the success of corneal transplantation. Participation of the transplanted eye in habitual binocular viewing is seldom evaluated post-operatively. In unilateral corneal disease, the transplanted eye may remain functionally inactive during binocular viewing due to its suboptimal visual acuity and poor image quality, vis-à-vis the healthy fellow eye.This study prospectively quantified the contribution of the transplanted eye towards habitual binocular viewing in 25 cases with unilateral transplants [40 yrs (IQR: 32-42 yrs and 25 age-matched controls [30 yrs (25-37 yrs]. Binocular functions including visual field extent, high-contrast logMAR acuity, suppression threshold and stereoacuity were assessed using standard psychophysical paradigms. Optical quality of all eyes was determined from wavefront aberrometry measurements. Binocular visual field expanded by a median 21% (IQR: 18-29% compared to the monocular field of cases and controls (p = 0.63. Binocular logMAR acuity [0.0 (0.0-0.0] almost always followed the fellow eye's acuity [0.00 (0.00 --0.02] (r = 0.82, independent of the transplanted eye's acuity [0.34 (0.2-0.5] (r = 0.04. Suppression threshold and stereoacuity were poorer in cases [30.1% (13.5-44.3%; 620.8 arc sec (370.3-988.2 arc sec] than in controls [79% (63.5-100%; 16.3 arc sec (10.6-25.5 arc sec] (p<0.001. Higher-order wavefront aberrations of the transplanted eye [0.34 μ (0.21-0.51 μ] were higher than the fellow eye [0.07 μ (0.05-0.11 μ] (p<0.001 and their reduction with RGP contact lenses [0.09 μ (0.08-0.12 μ] significantly improved the suppression threshold [65% (50-72%] and stereoacuity [56.6 arc sec (47.7-181.6 arc sec] (p<0.001.In unilateral corneal disease, the transplanted eye does participate in gross binocular viewing but offers limited support to fine levels of binocularity. Improvement in the transplanted

  16. An Analytical Measuring Rectification Algorithm of Monocular Systems in Dynamic Environment

    Directory of Open Access Journals (Sweden)

    Deshi Li

    2016-01-01

    Full Text Available Range estimation is crucial for maintaining a safe distance, in particular for vision navigation and localization. Monocular autonomous vehicles are appropriate for outdoor environment due to their mobility and operability. However, accurate range estimation using vision system is challenging because of the nonholonomic dynamics and susceptibility of vehicles. In this paper, a measuring rectification algorithm for range estimation under shaking conditions is designed. The proposed method focuses on how to estimate range using monocular vision when a shake occurs and the algorithm only requires the pose variations of the camera to be acquired. Simultaneously, it solves the problem of how to assimilate results from different kinds of sensors. To eliminate measuring errors by shakes, we establish a pose-range variation model. Afterwards, the algebraic relation between distance increment and a camera’s poses variation is formulated. The pose variations are presented in the form of roll, pitch, and yaw angle changes to evaluate the pixel coordinate incensement. To demonstrate the superiority of our proposed algorithm, the approach is validated in a laboratory environment using Pioneer 3-DX robots. The experimental results demonstrate that the proposed approach improves in the range accuracy significantly.

  17. Stereo improves 3D shape discrimination even when rich monocular shape cues are available.

    Science.gov (United States)

    Lee, Young Lim; Saunders, Jeffrey A

    2011-08-17

    We measured the ability to discriminate 3D shapes across changes in viewpoint and illumination based on rich monocular 3D information and tested whether the addition of stereo information improves shape constancy. Stimuli were images of smoothly curved, random 3D objects. Objects were presented in three viewing conditions that provided different 3D information: shading-only, stereo-only, and combined shading and stereo. Observers performed shape discrimination judgments for sequentially presented objects that differed in orientation by rotation of 0°-60° in depth. We found that rotation in depth markedly impaired discrimination performance in all viewing conditions, as evidenced by reduced sensitivity (d') and increased bias toward judging same shapes as different. We also observed a consistent benefit from stereo, both in conditions with and without change in viewpoint. Results were similar for objects with purely Lambertian reflectance and shiny objects with a large specular component. Our results demonstrate that shape perception for random 3D objects is highly viewpoint-dependent and that stereo improves shape discrimination even when rich monocular shape cues are available.

  18. Higher resolution stimulus facilitates depth perception: MT+ plays a significant role in monocular depth perception.

    Science.gov (United States)

    Tsushima, Yoshiaki; Komine, Kazuteru; Sawahata, Yasuhito; Hiruma, Nobuyuki

    2014-10-20

    Today, we human beings are facing with high-quality virtual world of a completely new nature. For example, we have a digital display consisting of a high enough resolution that we cannot distinguish from the real world. However, little is known how such high-quality representation contributes to the sense of realness, especially to depth perception. What is the neural mechanism of processing such fine but virtual representation? Here, we psychophysically and physiologically examined the relationship between stimulus resolution and depth perception, with using luminance-contrast (shading) as a monocular depth cue. As a result, we found that a higher resolution stimulus facilitates depth perception even when the stimulus resolution difference is undetectable. This finding is against the traditional cognitive hierarchy of visual information processing that visual input is processed continuously in a bottom-up cascade of cortical regions that analyze increasingly complex information such as depth information. In addition, functional magnetic resonance imaging (fMRI) results reveal that the human middle temporal (MT+) plays a significant role in monocular depth perception. These results might provide us with not only the new insight of our neural mechanism of depth perception but also the future progress of our neural system accompanied by state-of- the-art technologies.

  19. Incorporating a Wheeled Vehicle Model in a New Monocular Visual Odometry Algorithm for Dynamic Outdoor Environments

    Directory of Open Access Journals (Sweden)

    Yanhua Jiang

    2014-09-01

    Full Text Available This paper presents a monocular visual odometry algorithm that incorporates a wheeled vehicle model for ground vehicles. The main innovation of this algorithm is to use the single-track bicycle model to interpret the relationship between the yaw rate and side slip angle, which are the two most important parameters that describe the motion of a wheeled vehicle. Additionally, the pitch angle is also considered since the planar-motion hypothesis often fails due to the dynamic characteristics of wheel suspensions and tires in real-world environments. Linearization is used to calculate a closed-form solution of the motion parameters that works as a hypothesis generator in a RAndom SAmple Consensus (RANSAC scheme to reduce the complexity in solving equations involving trigonometric. All inliers found are used to refine the winner solution through minimizing the reprojection error. Finally, the algorithm is applied to real-time on-board visual localization applications. Its performance is evaluated by comparing against the state-of-the-art monocular visual odometry methods using both synthetic data and publicly available datasets over several kilometers in dynamic outdoor environments.

  20. Cortical dynamics of three-dimensional form, color, and brightness perception. 1. Monocular theory

    Energy Technology Data Exchange (ETDEWEB)

    Grossberg, S.

    1987-01-01

    A real-time visual-processing theory is developed to explain how three-dimensional form, color, and brightness percepts are coherently synthesized. The theory describes how several fundamental uncertainty principles that limit the computation of visual information at individual processing stages are resolved through parallel and hierarchical interactions among several processing stages. The theory provides unified analysis and many predictions of data about stereopsis, binocular rivalry, hyperacuity, McCollough effect, textural grouping, border distinctness, surface perception, monocular and binocular brightness percepts, filling-in, metacontrast, transparency, figural aftereffects, lateral inhibition within spatial frequency channels, proximity luminance covariance, tissue contrast, motion segmentation, and illusory figures, as well as about reciprocal interactions among the hypercolumns, blobs, and stripes of cortical areas V1, V2, and V4. Monocular and binocular interactions between a Boundary Contour (BC) System and a Feature Contour (FC) System are developed. The BC System, defined by a hierarchy of oriented interactions, synthesizes an emergent and coherent binocular boundary segmentation from combinations of unoriented and oriented scenic elements.

  1. A trajectory and orientation reconstruction method for moving objects based on a moving monocular camera.

    Science.gov (United States)

    Zhou, Jian; Shang, Yang; Zhang, Xiaohu; Yu, Wenxian

    2015-03-09

    We propose a monocular trajectory intersection method to solve the problem that a monocular moving camera cannot be used for three-dimensional reconstruction of a moving object point. The necessary and sufficient condition of when this method has the unique solution is provided. An extended application of the method is to not only achieve the reconstruction of the 3D trajectory, but also to capture the orientation of the moving object, which would not be obtained by PnP problem methods due to lack of features. It is a breakthrough improvement that develops the intersection measurement from the traditional "point intersection" to "trajectory intersection" in videometrics. The trajectory of the object point can be obtained by using only linear equations without any initial value or iteration; the orientation of the object with poor conditions can also be calculated. The required condition for the existence of definite solution of this method is derived from equivalence relations of the orders of the moving trajectory equations of the object, which specifies the applicable conditions of the method. Simulation and experimental results show that it not only applies to objects moving along a straight line, or a conic and another simple trajectory, but also provides good result for more complicated trajectories, making it widely applicable.

  2. Monocular 3D Reconstruction and Augmentation of Elastic Surfaces with Self-Occlusion Handling.

    Science.gov (United States)

    Haouchine, Nazim; Dequidt, Jeremie; Berger, Marie-Odile; Cotin, Stephane

    2015-12-01

    This paper focuses on the 3D shape recovery and augmented reality on elastic objects with self-occlusions handling, using only single view images. Shape recovery from a monocular video sequence is an underconstrained problem and many approaches have been proposed to enforce constraints and resolve the ambiguities. State-of-the art solutions enforce smoothness or geometric constraints, consider specific deformation properties such as inextensibility or resort to shading constraints. However, few of them can handle properly large elastic deformations. We propose in this paper a real-time method that uses a mechanical model and able to handle highly elastic objects. The problem is formulated as an energy minimization problem accounting for a non-linear elastic model constrained by external image points acquired from a monocular camera. This method prevents us from formulating restrictive assumptions and specific constraint terms in the minimization. In addition, we propose to handle self-occluded regions thanks to the ability of mechanical models to provide appropriate predictions of the shape. Our method is compared to existing techniques with experiments conducted on computer-generated and real data that show the effectiveness of recovering and augmenting 3D elastic objects. Additionally, experiments in the context of minimally invasive liver surgery are also provided and results on deformations with the presence of self-occlusions are exposed.

  3. Mobile Target Tracking Based on Hybrid Open-Loop Monocular Vision Motion Control Strategy

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    Cao Yuan

    2015-01-01

    Full Text Available This paper proposes a new real-time target tracking method based on the open-loop monocular vision motion control. It uses the particle filter technique to predict the moving target’s position in an image. Due to the properties of the particle filter, the method can effectively master the motion behaviors of the linear and nonlinear. In addition, the method uses the simple mathematical operation to transfer the image information in the mobile target to its real coordinate information. Therefore, it requires few operating resources. Moreover, the method adopts the monocular vision approach, which is a single camera, to achieve its objective by using few hardware resources. Firstly, the method evaluates the next time’s position and size of the target in an image. Later, the real position of the objective corresponding to the obtained information is predicted. At last, the mobile robot should be controlled in the center of the camera’s vision. The paper conducts the tracking test to the L-type and the S-type and compares with the Kalman filtering method. The experimental results show that the method achieves a better tracking effect in the L-shape experiment, and its effect is superior to the Kalman filter technique in the L-type or S-type tracking experiment.

  4. Cataract surgery: emotional reactions of patients with monocular versus binocular vision

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    Roberta Ferrari Marback

    2012-12-01

    Full Text Available PURPOSE: To analyze emotional reactions related to cataract surgery in two groups of patients (monocular vision - Group 1; binocular vision - Group 2. METHODS: A transversal comparative study was performed using a structured questionnaire from a previous exploratory study before cataract surgery. RESULTS: 206 patients were enrolled in the study, 96 individuals in Group 1 (69.3 ± 10.4 years and 110 in Group 2 (68.2 ± 10.2 years. Most patients in group 1 (40.6% and 22.7% of group 2, reported fear of surgery (p<0.001. The most important causes of fear were: possibility of blindness, ocular complications and death during surgery. The most prevalent feelings among the groups were doubts about good results and nervousness. CONCLUSION: Patients with monocular vision reported more fear and doubts related to surgical outcomes. Thus, it is necessary that phisycians considers such emotional reactions and invest more time than usual explaining the risks and the benefits of cataract surgery.Ouvir

  5. Monocular tool control, eye dominance, and laterality in New Caledonian crows.

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    Martinho, Antone; Burns, Zackory T; von Bayern, Auguste M P; Kacelnik, Alex

    2014-12-15

    Tool use, though rare, is taxonomically widespread, but morphological adaptations for tool use are virtually unknown. We focus on the New Caledonian crow (NCC, Corvus moneduloides), which displays some of the most innovative tool-related behavior among nonhumans. One of their major food sources is larvae extracted from burrows with sticks held diagonally in the bill, oriented with individual, but not species-wide, laterality. Among possible behavioral and anatomical adaptations for tool use, NCCs possess unusually wide binocular visual fields (up to 60°), suggesting that extreme binocular vision may facilitate tool use. Here, we establish that during natural extractions, tool tips can only be viewed by the contralateral eye. Thus, maintaining binocular view of tool tips is unlikely to have selected for wide binocular fields; the selective factor is more likely to have been to allow each eye to see far enough across the midsagittal line to view the tool's tip monocularly. Consequently, we tested the hypothesis that tool side preference follows eye preference and found that eye dominance does predict tool laterality across individuals. This contrasts with humans' species-wide motor laterality and uncorrelated motor-visual laterality, possibly because bill-held tools are viewed monocularly and move in concert with eyes, whereas hand-held tools are visible to both eyes and allow independent combinations of eye preference and handedness. This difference may affect other models of coordination between vision and mechanical control, not necessarily involving tools. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Functional characterization of antibodies against Neisseria gonorrhoeae opacity protein loops.

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    Jessica G Cole

    Full Text Available BACKGROUND: The development of a gonorrhea vaccine is challenged by the lack of correlates of protection. The antigenically variable neisserial opacity (Opa proteins are expressed during infection and have a semivariable (SV and highly conserved (4L loop that could be targeted in a vaccine. Here we compared antibodies to linear (Ab(linear and cyclic (Ab(cyclic peptides that correspond to the SV and 4L loops and selected hypervariable (HV(2 loops for surface-binding and protective activity in vitro and in vivo. METHODS/FINDINGS: Ab(SV cyclic bound a greater number of different Opa variants than Ab(SV linear, including variants that differed by seven amino acids. Antibodies to the 4L peptide did not bind Opa-expressing bacteria. Ab(SV (cyclic and Ab(HV2 (cyclic, but not Ab(SV (linear or Ab(HV2 linear agglutinated homologous Opa variants, and Ab(HV2BD (cyclic but not Ab(HV2BD (linear blocked the association of OpaB variants with human endocervical cells. Only Ab(HV2BD (linear were bactericidal against the serum resistant parent strain. Consistent with host restrictions in the complement cascade, the bactericidal activity of Ab(HV2BD (linear was increased 8-fold when rabbit complement was used. None of the antibodies was protective when administered vaginally to mice. Antibody duration in the vagina was short-lived, however, with <50% of the antibodies recovered 3 hrs post-administration. CONCLUSIONS: We conclude that an SV loop-specific cyclic peptide can be used to induce antibodies that recognize a broad spectrum of antigenically distinct Opa variants and have agglutination abilities. HV(2 loop-specific cyclic peptides elicited antibodies with agglutination and adherence blocking abilities. The use of human complement when testing the bactericidal activity of vaccine-induced antibodies against serum resistant gonococci is also important.

  7. Tratamento da úlcera corneana experimental com membrana amniótica Experimental corneal ulcer treated with amniotic membrane

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    Eliana Cristina Louza Monteiro

    2000-02-01

    examinations and the results were compared through variance analysis. Results: Morphometric results showed corneal ulcer in G2 at M1; corneal opacity was identified in the central area and was significantly larger in G1 at M3. New corneal vessels were more active in the G1 animals. Histopathologic evaluation revealed epithelial defects in two animals of G1 at M2, and in two of G2 at M1; stromal edema was more intense in G1, as well as the presence of new vessels. Conclusion: The use of homologous MA in the treatment of experimental corneal ulcer did not accelerate epithelial healing but it prevented stromal edema and new vessel formation. Epithelial healing was poorer in the central region of the cornea.

  8. Evaluation of a 345 nm Femtosecond Laser for Corneal Surgery with Respect to Intraocular Radiation Hazard.

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    Johannes Menzel-Severing

    Full Text Available We report our findings from a preclinical safety study designed to assess potential side effects of corneal ultraviolet femtosecond laser treatment on lens and retina.Refractive lenticules (-5 dpt with a diameter of 6 mm were created in the right cornea of eight Dutch Belted rabbits. Radiant exposure was 0.5 J/cm² in two animals and 18 J/cm² in six animals. The presence of lens opacities was assessed prior to and up to six months following laser application using Scheimpflug images (Pentacam, Oculus and backscatter analysis (Opacity Lensmeter 702, Interzeag. Ganzfeld flash and flicker electroretinogram (ERG recordings were obtained from both eyes prior to and up to six weeks following laser application. At the study endpoint, retinas were examined by light microscopy.Independent of energy dose applied, no cataract formation could be observed clinically or with either of the two objective methods used. No changes in ERG recordings over time and no difference between treated and untreated eye were detected. Histologically, retinal morphology was preserved and retinal pigment epithelium as well as photoreceptor inner and outer segments appeared undamaged. Quantitative digital image analysis did not reveal cell loss in inner or outer nuclear layers.Our analysis confirms theoretical considerations suggesting that ultraviolet femtosecond laser treatment of the cornea is safe for intraocular tissues. Transmitted light including stray light induces no photochemical effects in lens or retina at energy levels much higher than required for the clinical purpose. These conclusions cannot be applied to eyes with pre-existing retinal damage, as these may be more vulnerable to light.

  9. Oxygen-deficient metabolism and corneal edema.

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    Leung, B K; Bonanno, J A; Radke, C J

    2011-11-01

    Wear of low-oxygen-transmissible soft contact lenses swells the cornea significantly, even during open eye. Although oxygen-deficient corneal edema is well-documented, a self-consistent quantitative prediction based on the underlying metabolic reactions is not available. We present a biochemical description of the human cornea that quantifies hypoxic swelling through the coupled transport of water, salt, and respiratory metabolites. Aerobic and anaerobic consumption of glucose, as well as acidosis and pH buffering, are incorporated in a seven-layer corneal model (anterior chamber, endothelium, stroma, epithelium, postlens tear film, contact lens, and prelens tear film). Corneal swelling is predicted from coupled transport of water, dissolved salts, and especially metabolites, along with membrane-transport resistances at the endothelium and epithelium. At the endothelium, the Na+/K+ - ATPase electrogenic channel actively transports bicarbonate ion from the stroma into the anterior chamber. As captured by the Kedem-Katchalsky membrane-transport formalism, the active bicarbonate-ion flux provides the driving force for corneal fluid pump-out needed to match the leak-in tendency of the stroma. Increased lactate-ion production during hypoxia osmotically lowers the pump-out rate requiring the stroma to swell to higher water content. Concentration profiles are predicted for glucose, water, oxygen, carbon dioxide, and hydronium, lactate, bicarbonate, sodium, and chloride ions, along with electrostatic potential and pressure profiles. Although the active bicarbonate-ion pump at the endothelium drives bicarbonate into the aqueous humor, we find a net flux of bicarbonate ion into the cornea that safeguards against acidosis. For the first time, we predict corneal swelling upon soft-contact-lens wear from fundamental biophysico-chemical principles. We also successfully predict that hypertonic tear alleviates contact-lens-induced edema.

  10. Intermittent exotropia: comparative surgical results of lateral recti-recession and monocular recess-resect Exotropia intermitente: comparação dos resultados cirúrgicos entre retrocesso dos retos laterais e retrocesso-ressecção monocular

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    Vanessa Macedo Batista Fiorelli

    2007-06-01

    Full Text Available PURPOSE: To compare the results between recession of the lateral recti and monocular recess-resect procedure for the correction of the basic type of intermittent exotropia. METHODS: 115 patients with intermittent exotropia were submitted to surgery. The patients were divided into 4 groups, according to the magnitude of preoperative deviation and the surgical procedure was subsequently performed. Well compensated orthophoria or exo-or esophoria were considered surgical success, with minimum of 1 year follow-up after the operation. RESULTS: Success was obtained in 69% of the patients submitted to recession of the lateral recti, and in 77% submitted to monocular recess-resect. In the groups with deviations between 12 PD and 25 PD, surgical success was observed in 74% of the patients submitted to recession of the lateral recti and in 78% of the patients submitted to monocular recess-resect. (p=0.564. In the group with deviations between 26 PD and 35 PD, surgical success was observed in 65% out of the patients submitted to recession of the lateral recti and in 75% of the patients submitted to monocular recess-resect. (p=0.266. CONCLUSION: recession of lateral recti and monocular recess-resect were equally effective in correcting basic type intermittent exotropia according to its preoperative deviation in primary position.OBJETIVO: Comparar os resultados entre o retrocesso dos retos laterais e retrocesso-ressecção monocular, para correção de exotropia intermitente do tipo básico. MÉTODOS: Foram selecionados 115 prontuários de pacientes portadores de exotropia intermitente do tipo básico submetidos a cirurgia no período entre janeiro de 1991 e dezembro de 2001. Os planejamentos cirúrgicos seguiram orientação do setor de Motilidade Extrínseca Ocular da Clínica Oftalmológica da Santa Casa de São Paulo e basearam-se na magnitude do desvio na posição primária do olhar. Os pacientes foram divididos em 4 grupos, de acordo com a magnitude

  11. Partial-thickness corneal tissue restoration after a chemical burn

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    Galan A

    2016-04-01

    Full Text Available Alessandro Galan, Anton Giulio Catania, Giuseppe Lo Giudice San Paolo Ophthalmic Center, San Antonio Hospital, Padova, Italy Purpose: We describe a case of full-thickness corneal restoration after an acute corneal burn with an acid agent. Methods: A 32-year-old male reported painful discomfort, redness, photophobia, and a decrease in visual acuity in the left eye after a unilateral burn with an acid agent. Slit-lamp examination revealed massive corneal melting involving necrotic sequestrum of the entire corneal surface. Surgical approach was carried out in order to preserve residual ocular tissues. Results: Extensive corneal–conjunctival layer curettage of the necrotic tissue was performed showing perfectly clear undamaged deep lamellar corneal layers. The patient underwent multilayered amniotic membrane transplantation and total capsular–conjunctival flap in order to preserve ocular tissue from further melting or corneal perforation. A complete and spontaneous “restitutio ad integrum” of the corneal layers was shown during the follow-up. The cornea was perfectly clear with restored normal anatomical architecture. Conclusion: In this case, a spontaneous full-thickness corneal tissue restoration occurred after an acute chemical burn. Studies about the mechanisms whereby different cells interact and replicate within the stroma may unveil the biology behind corneal regeneration and transparency. Keywords: amniotic membrane, chemical burn, corneal healing

  12. Emodin ameliorates lipopolysaccharides-induced corneal inflammation in rats

    Institute of Scientific and Technical Information of China (English)

    Guo-Ling; Chen; Jing-Jing; Zhang; Xin; Kao; Lu-Wan; Wei; Zhi-Yu; Liu

    2015-01-01

    · AIM: To investigate the effect of emodin on pseudomonas aeruginosa lipopolysaccharides(LPS)-induced corneal inflammation in rats.· METHODS: Corneal infection was induced by pseudomonas aeruginosa LPS in Wistar rats. The inflammation induced by LPS were examined by slit lamp microscope and cytological checkup of aqueous humor.Corneal tissue structure was observed by hematoxylin and eosin(HE) staining. The activation of nuclear factor kappa B(NF-κB) was determined by Western blot.Messenger ribonucleic acid(m RNA) of tumor necrosis factor-α(TNF-α) and intercellular adhesion molecule-1(ICAM-1) in LPS-challenged rat corneas were measured with reverse transcription-polymerase chain reaction(RT-PCR).· RESULTS: Typical manifestations of acute corneal inflammation were observed in LPS-induce rat model,and the corneal inflammatory response and structure were improved in rats pretreated with emodin. Treatment with emodin could improve corneal structure, reduce corneal injure by reducing corneal inflammatory response. Emodin could inhibit the decreasing lever of inhibitor of kappa B alpha(IкBα) express, and the m RNA expression of TNF-α and ICAM-1 in corneal tissues was also inhibited by emodin. The differences were statistically significant between groups treated with emodin and those without treatment(P <0.01).·CONCLUSION: Emodin could ameliorate LPS-induced corneal inflammation, which might via inhibiting the activation of NF-κB.

  13. Ocular histopathological changes after eyeball enucleation induced by corneal trauma

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To observe the ocular histopathological changes aftereyeball enucleation induced by corneal trauma.Methods: Light microscopic examination was done on 117 eyeball specimens enucleated after corneal trauma (18 with corneal fissure and 99 with corneal perforating trauma).Results: Acute, subacute or chronic inflammatory changes, and fibrous membrane formation were observed in well-closed corneal wounds, whereas inflammation, atrophy and scar were observed in the focal tissues. But at the late period, secondary glaucoma, retinal detachment, endophthalmitis and eyeball atrophy resulted in blindness. Corneal fistula was observed in those with inadequate cure of wounds caused by ingrowth of corneal epithelium, embedment of iris and vitreous body, and large area of centrally located tissue deficiency of the corneal. A high incidence of endophthalmitis was noted due to the presence of corneal fistula. Severe inflammation was observed in the anterior segmental tissues with fibrous infiltration in the anterior chamber, which might result in rapid destruction of the eyeballs.Conclusions: Ocular pathology varies with the difference of the position, form, size and closing conditions of the corneal laceration after trauma.

  14. Anatomical characterization of central, apical and minimal corneal thickness

    Institute of Scientific and Technical Information of China (English)

    Federico; Saenz-Frances; Martha; Cecilia; Bermúdez-Vallecilla; Lara; Borrego-Sanz; Luis; Jaez; J; osé; Marìa; Martinez-de-la-Casa; Laura; Morales-Fernandez; Enrique; Santos-Bueso; Julián; Garcia-Sanchez; Julián; Garcia-Feijoo

    2014-01-01

    ·AIM: To anatomically locate the points of minimum corneal thickness and central corneal thickness(pupil center) in relation to the corneal apex.·METHODS: Observational, cross-sectional study, 299 healthy volunteers. Thickness at the corneal apex(AT),minimum corneal thickness(MT) and corneal thickness at the pupil center(PT) were determined using the pentacam. Distances from the corneal apex to MT(MD)and PT(PD) were calculated and their quadrant position(taking the corneal apex as the reference) determined:point of minimum thickness(MC) and point of central thickness(PC) depending on the quadrant position. Two multivariate linear regression models were constructed to examine the influence of age, gender, power of the flattest and steepest corneal axes, position of the flattest axis, corneal volume(determined using the Pentacam)and PT on MD and PD. The effects of these variables on MC and PC were also determined in two multinomial regression models.·RESULTS: MT was located at a mean distance of 0.909 mm from the apex(79.4% in the inferior-temporal quadrant). PT was located at a mean distance of 0.156 mm from the apex. The linear regression model for MD indicated it was significantly influenced by corneal volume(B =-0.024; 95% CI:-0.043 to-0.004). No significant relations were identified in the linear regression model for PD or the multinomial logisticregressions for MC and PC.·CONCLUSION: MT was typically located at the inferiortemporal quadrant of the cornea and its distance to the corneal apex tended to decrease with the increment of corneal volume.

  15. Anatomical characterization of central, apical and minimal corneal thickness

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    Federico Saenz-Frances

    2014-08-01

    Full Text Available AIM: To anatomically locate the points of minimum corneal thickness and central corneal thickness (pupil center in relation to the corneal apex.METHODS: Observational, cross-sectional study, 299 healthy volunteers. Thickness at the corneal apex (AT, minimum corneal thickness (MT and corneal thickness at the pupil center (PT were determined using the pentacam. Distances from the corneal apex to MT (MD and PT (PD were calculated and their quadrant position (taking the corneal apex as the reference determined:point of minimum thickness (MC and point of central thickness (PC depending on the quadrant position. Two multivariate linear regression models were constructed to examine the influence of age, gender, power of the flattest and steepest corneal axes, position of the flattest axis, corneal volume (determined using the Pentacam and PT on MD and PD. The effects of these variables on MC and PC were also determined in two multinomial regression models.RESULTS: MT was located at a mean distance of 0.909 mm from the apex (79.4% in the inferior-temporal quadrant. PT was located at a mean distance of 0.156 mm from the apex. The linear regression model for MD indicated it was significantly influenced by corneal volume (B=-0.024; 95%CI:-0.043 to -0.004. No significant relations were identified in the linear regression model for PD or the multinomial logistic regressions for MC and PC.CONCLUSION: MT was typically located at the inferior-temporal quadrant of the cornea and its distance to the corneal apex tended to decrease with the increment of corneal volume.

  16. Catarata polar anterior piramidal deslocada para a câmara anterior causando edema de córnea: relato de caso Corneal edema caused by a pyramidal anterior polar cataract dislocated to the anterior chamber: case report

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    Ramon Coral Ghanem

    2004-08-01

    Full Text Available Cataratas polares anteriores piramidais são opacidades cônicas que se projetam para a câmara anterior a partir da cápsula anterior do cristalino. Na grande maioria dos pacientes a opacidade permanece aderida e estável durante toda a vida. O objetivo deste trabalho é documentar uma manifestação incomum desse tipo de catarata: a deiscência espontânea das pirâmides para a câmara anterior causando descompensação endotelial e edema corneal bilateral. Relatamos o caso de uma paciente feminina, de 66 anos, branca, que apresentava edema corneal localizado inferiormente no olho direito associado à lesão nodular branco-esclerótica compatível com a pirâmide anterior da catarata polar. O olho esquerdo apresentava edema corneal difuso intenso e presença de uma catarata polar anterior com a região piramidal deslocada para a câmara anterior. Sabe-se que a pirâmide anterior pode permanecer inabsorvida na câmara anterior por longo período, pois é composta de tecido colágeno denso. Isto causa perda endotelial progressiva e edema corneal e deve ser considerada indicação de remoção cirúrgica da catarata polar anterior e de seu fragmento. Ressalta-se, também, a importância do bom senso no julgamento das cataratas polares anteriores, considerando-se tamanho da opacidade, simetria das opacidades e componente cortical associado, na tentativa de se evitar ambliopia.Pyramidal anterior polar cataracts are conical opacities that project into the anterior chamber from the anterior capsule of the lens. In the vast majority of patients the opacity remains bound and stable throughout life. We report an unusual complication of this type of cataract: spontaneous dehiscence of the pyramids to the anterior chamber causing bilateral endothelial damage and corneal edema. 66-year-old white woman presented with inferior corneal edema in the right eye and diffuse corneal edema in the left eye. A white nodular lesion was observed in the inferior angle

  17. The perceived visual direction of monocular objects in random-dot stereograms is influenced by perceived depth and allelotropia.

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    Hariharan-Vilupuru, Srividhya; Bedell, Harold E

    2009-01-01

    The proposed influence of objects that are visible to both eyes on the perceived direction of an object that is seen by only one eye is known as the "capture of binocular visual direction". The purpose of this study was to evaluate whether stereoscopic depth perception is necessary for the "capture of binocular visual direction" to occur. In one pair of experiments, perceived alignment between two nearby monocular lines changed systematically with the magnitude and direction of horizontal but not vertical disparity. In four of the five observers, the effect of horizontal disparity on perceived alignment depended on which eye viewed the monocular lines. In additional experiments, the perceived alignment between the monocular lines changed systematically with the magnitude and direction of both horizontal and vertical disparities when the monocular line separation was increased from 1.1 degrees to 3.3 degrees . These results indicate that binocular capture depends on the perceived depth that results from horizontal retinal image disparity as well as allelotropia, or the averaging of local-sign information. Our data suggest that, during averaging, different weights are afforded to the local-sign information in the two eyes, depending on whether the separation between binocularly viewed targets is horizontal or vertical.

  18. Measuring perceived depth in natural images and study of its relation with monocular and binocular depth cues

    Science.gov (United States)

    Lebreton, Pierre; Raake, Alexander; Barkowsky, Marcus; Le Callet, Patrick

    2014-03-01

    The perception of depth in images and video sequences is based on different depth cues. Studies have considered depth perception threshold as a function of viewing distance (Cutting and Vishton, 1995), the combination of different monocular depth cues and their quantitative relation with binocular depth cues and their different possible type of interactions (Landy, l995). But these studies only consider artificial stimuli and none of them attempts to provide a quantitative contribution of monocular and binocular depth cues compared to each other in the specific context of natural images. This study targets this particular application case. The evaluation of the strength of different depth cues compared to each other using a carefully designed image database to cover as much as possible different combinations of monocular (linear perspective, texture gradient, relative size and defocus blur) and binocular depth cues. The 200 images were evaluated in two distinct subjective experiments to evaluate separately perceived depth and different monocular depth cues. The methodology and the description of the definition of the different scales will be detailed. The image database (DC3Dimg) is also released for the scientific community.

  19. Monocular SLAM for Visual Odometry: A Full Approach to the Delayed Inverse-Depth Feature Initialization Method

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    Rodrigo Munguía

    2012-01-01

    Full Text Available This paper describes in a detailed manner a method to implement a simultaneous localization and mapping (SLAM system based on monocular vision for applications of visual odometry, appearance-based sensing, and emulation of range-bearing measurements. SLAM techniques are required to operate mobile robots in a priori unknown environments using only on-board sensors to simultaneously build a map of their surroundings; this map will be needed for the robot to track its position. In this context, the 6-DOF (degree of freedom monocular camera case (monocular SLAM possibly represents the harder variant of SLAM. In monocular SLAM, a single camera, which is freely moving through its environment, represents the sole sensory input to the system. The method proposed in this paper is based on a technique called delayed inverse-depth feature initialization, which is intended to initialize new visual features on the system. In this work, detailed formulation, extended discussions, and experiments with real data are presented in order to validate and to show the performance of the proposal.

  20. The Effect of Long Term Monocular Occlusion on Vernier Threshold: Elasticity in the Young Adult Visual System.

    Science.gov (United States)

    1986-06-01

    experiment, Brown and Salinger (1975) found a decrease of the X-cell 2 population in the lateral geniculate body of the adult cat. These investigators...D.L., and Salinger , W.L., "Loss of X-Cells in Lateral Geniculate Nucleus with Monocular Paralysis. Neural Plasticity in the Adult Cat", Science, 189