Effect of variable tinted spectacle lenses on visual performance in control subjects.

PURPOSE: To evaluate quantitatively the effects of tinted spectacle lenses on visual performance in individuals without visual pathology. METHODS: Twenty-five subjects were assessed by measuring contrast sensitivity with and without glare. Gray, brown, yellow, green, purple, and blue lens tints were evaluated. Measurements were repeated with each lens tint and with a clear lens, and the order was counterbalanced within and between subjects. Glare was induced with a modified brightness acuity tester. RESULTS: All subjects demonstrated an increase in contrast thresholds under glare conditions for all lens tints. However, purple and blue lens tints resulted in the least amount of contrast threshold increase; the yellow lens tint resulted in the largest contrast threshold increase. CONCLUSIONS: Purple and blue lens tints may improve contrast sensitivity in control subjects under glare conditions.     

Effect of filters upon object color naming

Color constancy refers to the phenomenon that the perceived colors of objects are largely unaltered by changes in the illuminant or by viewing through colored filters. Deviations from perfect constancy, induced by filters similar to ophthalmic tints, were investigated in this study. Munsell color chips were forced-choice categorized into R, Y, G, or B. This accurately located the boundaries between these colors on the chip color circle. Testing was performed through 23 different adaptive conditions and chromaticity shifts created by filters. The technique simulates real world situations in which the chromaticity of the objects and the adaptation of the observer both change. Generally, color constancy held quite well. The boundaries between the four colors shifted for some filters, indicating some deviation from perfect constancy. Red filters resulted in more color chips appearing red, blue and green filters resulted in more chips appearing blue, and filters along the Planckian locus resulted in more chips appearing green.     

Do long wavelength pass filters improve low vision performance?

It has been suggested that the wearing of band-pass tints may improve the contrast performance in certain ocular conditions. We examined this by measuring grating visual acuity (VA) for targets of various contrasts. The benefits of Corning CPF 511, 527 and 550 lenses, and neutral density (ND) filters were examined with and without the presence of glare. Generally, patients with anterior sector conditions showed improved performance with band-pass filters (not with ND filters). It is suggested that the filter reduces the scatter within the ocular media. People with retinitis pigmentosa or diabetic retinopathy rarely benefited. The CPF 511 most frequently improved VA followed by CPF 527 and 550 respectively. We suggest that a condition of glare is incorporated when assessing suitability with tints.     

A utility analysis correlation with visual acuity: methodologies and vision in the better and poorer eyes

Objective: To ascertain the correlation between visual acuity levels and ophthalmic utility values obtained using time tradeoff and standard gamble utility analysis methodologies. Methods: Three hundred twenty-five consecutive patients with visual loss to 20/40 or less in at least one eye with predominantly vitreoretinal pathology were evaluated in a cross-sectional fashion using a standardized testing methodology to obtain ophthalmic time tradeoff and standard gamble utility values. Spearman correlation coefficients were employed to correlate the utility values with visual acuity in better seeing and poorer seeing eyes. Results: The Spearman correlation coefficient for time tradeoff utility values and vision in the better seeing eye was 0.455 (p < 0.001), while that for time tradeoff utility values and visual acuity in the poorer seeing eye was 0.268 (p < 0.001). The coefficient for standard gamble utility values and the better seeing eye was 0.371 (p < 0.001), while that for standard gamble utility values and vision in the poorer seeing eye was 0.250 (p < 0.001). Conclusions: There is a greater correlation between ophthalmic utility values and vision in the better seeing eye, as versus vision in the poorer seeing eye. Time tradeoff ophthalmic utility values demonstrate a greater correlation with vision in the better seeing eye than do standard gamble utility values.     

Low-energy dynamic indentation method for analysis of ophthalmic materials.

PURPOSE: The purpose of the present work is to understand and study the mechanical behavior and critical parameters of ophthalmic polymers. The article introduces a novel low-energy indentation method that can be used to study and optimize the mechanical properties of ophthalmic materials. The technique has been developed in the frame of a larger study on the impact resistance of materials. METHOD: The low-energy dynamic indentation method is based on a lumped mass-spring model solved by a 4th-order Runge-Kutta numerical method. The model can be used to predict the material response to the indentation of a hemi-spherical tip and calculate the elasticity modulus of materials, dissipated energy during impact, residual deformation after impact, indentation depth and their conservative and nonconservative components. RESULTS: As an example, two ophthalmic polymers were compared: CR-39 as the universal ophthalmic standard, and Superfin as Indo Lens U.S., standard. Results showed the model is in good agreement with experimental data and allowed to obtain elasticity moduli for both materials, which showed similar values. A larger conservative component of the displacement for Superfin was also obtained and a smaller calculated residual displacement, which is indicative of less deformed material after low energy impacts. CONCLUSIONS: The model can satisfactorily predict the behavior of materials under low energy indentation situations. In addition, it can be used to distinguish two apparently similar materials, such as CR-39 and Superfin, and classify them according to their response to these kind of indentations. The technique could be used as a very powerful tool to improve ophthalmic materials.     

眼内药物实验研究应注意的一些问题

新药或已知药物在眼病的应用研究是眼科研究的一个主要课题.但近年发表的眼科药物实验研究文献中,反映出部分实验研究存在缺乏系统、规划和规范;没有细胞学筛选实验,直接进行动物实验;缺乏与已知药物对照等问题.为提高相关研究的质量,研究者应该熟悉新药研究的规范步骤、应用体外细胞学模型以及活体动物模型进行药物筛选和效果评估研究的基本规则.     

Proficiency and patient acceptance of ophthalmic medical assistants

We assessed the accuracy of ten ophthalmic technologist trainees (OTs) in commonly performed tasks of the ophthalmic examination. Results were derived from 224 patient examinations; 160 patients were examined both by OTs and ophthalmology residents, and an additional 64 were examined both by OTs, residents, and a faculty ophthalmologist. In measurement tasks, there was no significant difference in the results produced by the three types of providers. In identifying abnormalities of the globe and adnexae, and in history-taking, OT performance was nearly as accurate as that of the residents, when compared to the findings of the faculty ophthalmologist. In diagnosis and disposition, OT performance fell below the physician standard, especially in difficult cases. Patient acceptance of both formally trained and on-the-job trained ophthalmic medical assistants was very high. These results suggest that assistants with training comparable to that of the participants in this study may perform a large proportion of the routine ophthalmic examination without sacrificing quality or satisfaction with care.     

Ophthalmic laser microendoscope endophotocoagulation.

PURPOSE: The purpose of this article is to describe the function of the ophthalmic laser microendoscope as it pertains to endophotocoagulation in the management of vitreoretinal disease. METHODS: Fifty-four consecutive vitrectomies with endophotocoagulation were performed using the ophthalmic laser microendoscope instead of endoillumination and endophotocoagulation probes. Intraoperative and postoperative efficacy and complications were evaluated. RESULTS: The ophthalmic laser microendoscope was used to illuminate and view the retina and to deliver diode laser energy in the management of posterior retinal breaks, proliferative retinopathies, and proliferative vitreoretinopathy. The technique of endophotocoagulation was similar to that used routinely in vitreoretinal surgery. The photocoagulation lesions that were created were identical to those delivered by standard endophotocoagulation probes. Intraoperative complications were few, consisting of transient mild retinal or choroidal hemorrhages. Severe postoperative complications related to endophotocoagulation or to use of the ophthalmic laser microendoscope were not observed. CONCLUSION: The ophthalmic laser microendoscope appears to be a safe and effective method of delivering diode laser energy to the retina while simultaneously providing illumination, video recording, and a clear endoscopic view despite anterior segment conditions that might otherwise preclude adequate visualization and treatment. Fewer instrument insertions/removals were required for endophotocoagulation. Post-treatment search for peripheral iatrogenic retinal breaks was accomplished by endoscopy.     

视力表应用常见误解之分析

视力表是眼科临床和视觉科学研究领域的重要检查工具,现针对临床和研究中比较容易被误解的视标增率、视力记录和部分研究论文中出现的视力统计等问题进行阐述,并以此解读视力表的设计核心内容,这将有利于对视力表的科学理解,避免应用上的失误,使视力表的使用更加科学和规范,如此可获得准确的视力记录和统计结果,使之更好科学应用于视力普查、眼科临床和科研等。     

全球眼科图像公开数据库使用指南（2022）

可公开获取的医学数据是数字健康研究的宝贵资源。目前，一些包含眼科图像的公开数据库常被用于机器学习的研究中，但如何规范高效地使用这些数据库尚无统一标准。本指南旨在筛选确定部分公开可用的眼科图像数据库，详细描述其包含的疾病类型、图像来源和成像方式。使用MEDLINE、Google搜索引擎和Google数据集搜索，确定了94个开放获取数据库，包含来自122 364名患者的507 724张图片和125段视频。该指南为眼科数据库相关研究提供了帮助与参考。同时，指南还发现数据库中不同人群和疾病群体代表性的差距越来越大。改进的元数据报告将使研究人员能够根据他们的需要访问最合适的数据库，并最大限度地发挥这些图像数据资源的作用。     

An alternative to the Drop Ball Test for the measurement of ophthalmic glass fracture resistance.

The Drop Ball Test (DBT) has some distinct disadvantages both as a standard measurement for ophthalmic lens fracture resistance and as a research tool. The Static Test (ST) was devised to allow a load and enzrgy analysis of the DBT and enable more rapid and accurate testing of large ophthalmic lens samples. It was found that over 50% of the energy generated in the DBT is absorbed by the lens mount instead of the test lens. This means that the standard DBT height of 50 inches is more an indication of DBT components than lens fracture resistance. Static testing of non-tempered, heat tempered and chemically tempered lenses correlated well with former DBT studies. The ST, however, allowed lens fracture resistance to be represented in pounds-load, a value better understood practically and mathematically.     

Spectral transmittance of tinted hydrogel contact lenses

The visible light and ultraviolet (UV) radiation transmission was measured for four different tints from two contact lens companies. It was found that luminous transmittance ranged from 60 to 82% and mean UV transmission from 15 to 74% for the lenses under investigation. Differences in luminous transmittance between the two lenses of each tint evaluated were generally within 1%, which was also the approximate accuracy of the technique.     

眼科门诊药物临床试验标准操作规程探讨

目的:探讨眼科门诊进行药物临床试验的标准操作规程。方法:对南通大学附属医院已经在门诊完成的2种眼药水的药物临床试验方案设计、实施情况、受试者选择、知情同意、药物管理和质量控制等进行回顾。结果:两种药物临床试验得以成功完成。通过试验,探索出了一套眼科门诊进行药物临床试验工作的标准操作规程。结论:眼科门诊进行眼药水的药物临床试验与其他药物剂型及在住院患者中进行临床试验相比,有其特殊性,良好的方案设计、专人负责、严格按照GCP进行是保证药物临床试验顺利完成的关键。     

Pulfrich revisited

The Pulfrich phenomenon is a stereo-illusion resulting from latency disparities in the visual pathways. It is common after optic neuritis, but is also to be found with other conditions. The symptoms are often difficult for the patient to explain and for the physician to understand. Symptoms may be sufficiently disturbing to significantly interfere with a patient's life (e.g., prevention of driving). Treatment with the use of monocular tints is simple and effective.     

The Hoya ULT-2000 Universal Light I Transmission Meter: An Assessment of Its Performance

ABSTRACT The performance of the Hoya ULT-2000 Universal Light Transmission Meter was investigated in three experiments. Firstly the effect of orientation of gradient tinted lenses was investigated, secondly the linearity of the meter was established and thirdly comparison was made with the data obtained with an Hitachi 100-50 Spectrophotometer. Sources of errors are discussed and the possibility of the ULT-2000 being used for assessing performance of tints with respect to Australian Standard 1067–1971 is commented upon.     

Monocular visual-field testing under binocular conditions

Spectacles with plastic polarizers in front of each eye, with the polarizing axis at right angles to each other, permit monocular visual-field tangent screen testing under binocular conditions, provided a rotatable polarizer is attached in front of the standard ophthalmic slide projector which generates the test light.     

Acute visual loss after preoperative embolization of an ethmoidal metastasis

An unintentional embolization of retinal arteries is rare and has been documented as a complication after embolization of arteries supplying head and neck tumors. However, occlusion of the central retinal artery with severe loss of vision has never been reported to be a complication from embolization of tumor-supplying ethmoidal branches of the ophthalmic artery. A 40 year-old male patient with a history of right nephrectomy for renal cell carcinoma underwent preoperative radiological embolization of an ethmoidal metastasis after having experienced a life-threatening sinus bleeding. Repeated probing of the ophthalmic artery with an endovascular microcatheter for particle embolization of the tumor-supplying arteries was performed under anticoagulation with heparin. Postoperatively, a standard ophthalmological examination including extended vascular evaluation by angiography was performed. After extended probing of the ophthalmic artery a marked reduction in its blood flow occurred. Despite post-interventional imaging showing persisting perfusion of the central retinal and ciliary arteries, the patient developed complete loss of vision on this side four days later. At this time fundoscopy and fluorescein angiography revealed a recanalized central artery occlusion, while indocyanin angiography showed infarctions of the choroid. Radiological intervention via the ophthalmic artery can result in complete loss of vision, even after limited and transient obstruction of the vessel.