常用远用视力表的临床价值对照研究

目的:分析《标准对数视力表》与《低视力视力表》对远用视力检查的临床意义及临床价值。方法:随机抽取本院验光部验光患者59例(118眼),每位患者分别进行两种视力表的远用视力检查,然后记录裸眼视力以及矫正视力检查结果,再进行配对设计资料检验。结果:裸眼视力检查t=2.9944,矫正视力检查t=3.5564,P<0.05,两种视力表无论是裸眼视力还是矫正视力在统计学上均有显著性差异。结论:两种视力表的视力检查结果有所差异,裸眼视力相差19.953′视角,矫正视力相差15.849′视角,且低视力专用视力表的均值均小于标准对数视力表。     

助视器在低视力儿童中的应用

目的探讨自行来院就诊低视力儿童的病因及低视力康复疗效,方法对门诊筛查视力低常儿童进行散瞳验光、眼底等检查,诊断为低视力者,应用远用、近用助视器进行视力康复训练;结果在25例低视力儿童中,(1)病因以先天性眼球震颤合并屈光不正多见,占76.00%;(2)20例选择康复远视力,最佳矫正远视力在0.1～<0.3,用4X、6X单筒近距远距观察镜康复远视力达到≥1.0,脱残率100%;(3)5例选择康复近视力,最佳矫正近视力<0.3~0.1,经过使用2.5X、3X、4X直柄放大镜和2.5X木马放大镜康复近视力≥0.5,近视力康复有效率100%。结论应用助视器能有效提高低视力儿童的远、近视力和视觉质量,让患儿有机会具备接受正常教育的用眼条件,因此,早发现、早诊断、早矫正、早康复,对低视力儿童的身心健康、拓宽知识领域、升学、就业具有积极地意义。     

Changing from Snellen to LogMAR: debate or delay?

Visual acuity is the most commonly used test to assess visual function. The Snellen chart is the universally accepted tool for testing visual acuity despite its poor reliability and reproducibility. Newer logMAR charts are now available that have negated the disadvantages of the Snellen chart. However, these charts are not being used regularly in daily practice. This article discusses the reasons for the delayed acceptance of the logMAR chart.     

Principles of modern low vision rehabilitation

Low vision rehabilitation is a new emerging subspecialty drawing from the traditional fields of ophthalmology, optometry, occupational therapy, and sociology, with an ever-increasing impact on our customary concepts of research, education, and services for the visually impaired patient. A multidisciplinary approach and coordinated effort are necessary to take advantage of new scientific advances and achieve optimal results for the patient. Accordingly, the intent of this paper is to outline the principles and details of a modern low vision rehabilitation service. All rehabilitation attempts must start with a first hand interview (the intake) for assessing functionality and priority tasks for rehabilitation, as well as assessing the patient's all-important cognitive skills. The assessment of residual visual functions follows the intake and offers a unique opportunity to measure, evaluate, and document accurately the extent of functional loss sustained by the patient from disease. An accurate assessment of residual visual functions includes assessment of visual acuity, contrast sensitivity, binocularity, refractive errors, perimetry, oculomotor functions, cortical visual integration, and light characteristics affecting visual functions. Functional vision assessment in low vision rehabilitation measures how well one uses residual visual functions to perform routine tasks, using different items under various conditions, throughout the day. Of the many functional vision skills known, reading skills is an obligatory item for all low vision rehabilitation assessments. Results of assessment guide rehabilitation professionals in developing rehabilitation plans for the individual and recommending appropriate low vision devices. The outcome from assessing residual visual functions is detection of visual functions that can be improved with the use of optical devices. Methods for prescribing devices such as image relocation with prisms to a preferred retinal locus, field displacement to primary gaze position, field expansion, and manipulation of light are practiced today in addition to, or instead of, magnification. Correction of refractive errors, occlusion therapy, enhancement of oculomotor skills, and field restitution are additional methods now available for prescribing devices leading to rehabilitation of visual functions. The outcome from assessing residual functional vision is detection of functional vision that can be improved with the use of vision therapy training. After restoration of optimal residual visual functions is achieved with optical devices, one can follow with training programs for restoration of lost vision-related skills. If an optical dispensary is available where prescribing of low vision devices routinely take place, this will help ensure familiarity and specialization of the dispensary and staff with low vision devices and their special dispensing requirements. The dispensing of low vision devices is an opportunity to introduce the device to the patient, train the patient in the correct use of the device for the task selected, and create a direct and continuous connection with the patient until the next encounter. Following assessment, prescribing, and dispensing of devices, a low vision practitioner, ophthalmologist or optometrist, is responsible for recommending and prescribing vision therapy training to improve residual functional vision. An attempt to present a template for a comprehensive modern low vision rehabilitation practice is made here by summarizing scientific developments in the field and stressing the multidisciplinary involvement required for this kind of practice. It is hoped that this paper and other initiatives from colleagues, the public, and government will promote and raise awareness of modern low vision rehabilitation for the benefit of all.     

Habitual visual acuity in a large urban cohort of Western India and factors influencing poor habitual vision

Purpose:The aim of this study was to determine habitual visual acuity (HVA) in a large urban cohort in western India and identify factors associated with poor HVA.Methods:This was a prospective study conducted over 10 days in September 2018 to assess the HVA in individuals attending a 10-day festival in Western India. Participants who volunteered to undergo vision screening and also filled the questionnaire form pertaining to demographic information including their age, gender, address, income, and educational status were included in this study. HVA was recorded with the distance correction that the participants were wearing when they attended the screening. The study evaluated the prevalence of visual acuity 6/6 or <6/6, 6/12, and 6/18 and the factors associated with lower visual acuity.Results:Of the 6300 participants, 1660 (26.3%) were females. Majority of the participants were from urban background (6084, 96.6%) and were of younger age group (18–40 years––3786, 60.1%; 41–60 years––2187, 34.7%; >60 years––327, 5.2%). HVA was recorded as 6/6 both eyes in 4136 (65.6%), at least 6/12 both eyes in 5691 (90.3%), and at least 6/18 both eyes in 5974 (94.8%) individuals. Only 11 patients (0.17%) had VA worse than 6/60 with only 3 patients (0.003%) having bilateral VA <6/60. Older age, female sex, lower education status, and low annual income were significant risk factors for poor HVA.Conclusion:Poor education, lower income, female gender, and old age are significantly associated with poor HVA even in urban Western India despite relatively easy access to affordable eye care facilities.     

Fourth nerve palsy as an initial sign of internal carotid-posterior communicating artery aneurysm

A 54-year-old female complained of vertical diplopia on downward gaze with a slight headache lasting two days. When she gazed in a nasal lower direction, right hypertropia became obvious and the Bielschowsky head-tilt test was positive. A trochlear nerve palsy of right eye was diagnosed. Several examinations were performed, including blood chemical and serological examinations, plain CT examination, and cerebrospinal fluid examination. Three days after appearance of the trochlear nerve palsy, oculomotor nerve palsy of right eye occurred with severe ocular and head pain, and a four-vessel study disclosed a large aneurysm at the IC-PC portion and two more aneurysms at the distal portion of the middle cerebral artery. This is a very rare case of trochlear nerve palsy as the initial sign of IC-PC aneurysm and the pathogenesis of trochlear nerve palsy was discussed.     

Visual function in autism spectrum disorders: a critical review

Studies have shown considerable evidence of visual dysfunction in autism spectrum disorders. Anomalies in visual information processing can have a major effect on the life quality of individuals with autism spectrum disorders. We summarise the hypotheses and theories underlying neural aetiologies and genetic factors that cause these disorders, as well as the possible influences of unusual sensory processing on the communications and behaviour characterised by the autistics. In particular, we review the impact of these dysfunctions on visual performance.     

Assessment of visual acuity by evoked potential recording: Ambiguity caused by temporal dependence of spatial frequency selectivity

The spatial-frequency selectivity of pattern evoked potentials depends on the stimulus repetition rate: responses to low spatial frequencies are emphasized by stimulating at 16–20 Hz, while responses to high spatial frequencies are emphasized at 5–8 Hz. These findings are consistent with the suggestion that pattern EP's are a mixture of pattern responses and responses to local flicker. To a first approximation the “local flicker” responses resemble EP's produced by flickering a light similar to the patterned stimulis in all respects except for absence of pattern. Any developmental changes in the temporal tuning of pattern responses and/or local flicker responses might distort the results of studies in which pattern EP's have been used as an index of either (a) the development of visual acuity or (b) acuity changes due to visual deprivation. Methods of minimizing this problem are suggested.     

The measurement of visual acuity in children: an evidence‐based update

Over the past decade, a number of large clinical trials have provided important information relating to the reliability and repeatability of commonly used paediatric tests of vision and their role in the diagnosis and management of paediatric ocular diseases. The aim of this review is to summarise recent findings on the use of paediatric visual acuity tests in clinical practice and to discuss the validity and accuracy of visual acuity measurements in infants and young children. We provide a broad overview of the benefits and challenges of measuring visual acuity in children and then discuss age‐appropriate tests for measuring visual acuity in infants through to school‐age children. We also discuss normative values for visual acuity in each age group and, where possible, provide comparisons of results between tests with a particular focus on the importance of optotype design.     

Results obtained with low vision aids

In this retrospective study of 261 patients (181 female and 80 male) the results obtained in a special low vision clinic are described. The mean age of the patients was 73.5 years (range 16–95 years). Visual acuity of the best eye was 0.08 in 26 patients (10.0%); better than 0.08 but 0.25 in 130 (50%); 0.30 in 62 (23.8%) and better than 0.30 in 42 patients (16.1%). Persons with a visual acuity better than 0.30 either could not read normal print or had restricted visual fields. Main causes of visual impairment were macular degeneration (38.9%), diabetic retinopathy (16.1%), glaucoma (8.4%) and cataract (7.4%). Low vision aids could be prescribed for 208 persons (79.7%). Follow-up of an average of 12 months (range, 3–22 months) was carried out in 250 cases (96%). In this period 24 patients (9%) died. At least 161 persons (62%) used their aids regularly, i.e. 77% of the patients who were given a low vision aid.     

Are there age differences in the accommodative response curve between 3 and 14 years of age?

The monocular ocular accommodative responses of 118 emmetropic children, aged from 3 to 14 years, were measured at five different stimulus distances (0, 1, 2, 3, 4 D) from the principal plane of the eye with a Canon Autoref R-1. The change in the accommodative response curve in emmetropic children between 3 and 14 years old was found to be negligible.     

运动员视觉保健

视觉作为在人类多种感观认识功能中占主导地位的感知方式，对体育竞技中的各类感觉运动性活动具有举足轻重的作用。运动视觉的医疗职能包括：①预防和治疗体育和竞技运动中造成的眼部损伤。②评估和矫正某些影响协调性运动机能的视功能异常。③针对体育运动的环境性因素展开专业性的角膜接触镜业务，并对一些对眼动、视力和应急状态具有特殊要求的竞技项目提供帮助。④基于视觉和环境等因素的考虑，向专业运动员提供特制的眼部保护装置和助视仪器。⑤评估与某些竞技运动项目密切相关的视觉功能及技巧。⑥通过对运动员的视功能强化训练进而提高其运动成绩。⑦向运动员、教练员或整个团队提供有助于提高运动成绩的视觉功能及技巧的咨询。人们一直都很关注视觉功能与运动成绩之间的联系，许多专家与临床医生都试图寻求与特定的运动技能相关的特殊视觉技巧，进而建立精确的方法予以评估。运动员具有比非运动员更好的视觉功能，而与一般的运动员比较，顸尖水平的运动员往往从优异的视觉功能中获益更大。不同的视觉功能对于帮助运动员取得优秀成绩的作用在运动项目中是有所差异的。运动视觉专家必须区分出哪些视功能是与运动相关的关键性的视功能，并用最恰当的方法对其进行评估。不同的运动项目，对视觉功能的要求也常常不同。运动员的验光矫正包括运动或娱乐过程中配戴特制的框架眼镜及角膜接触镜。在决定最佳处方的同时，应考虑最适合的镜片种类、镜框设计、染色特征和应考虑的安全防护因素。基于运动和环境需要的角膜接触镜染色工艺是目前正在研究和发展中的高新技术，其产品即将面世，在运动或娱乐场所的不同光照环境下能够减少眩光，提高视觉舒适性，增强视功能。运动型太阳眼镜光学性能的改善和上述染色型角膜接触镜的发展，将为运动员们减少眩光提供了可能的解决方法。为运动员们提供视觉保健时，首先应予考虑的问题是减少在训练和比赛中的眼部损伤。通常在采用了这些眼保措施后，绝大多数损伤是可以避免的。运动员所接收的视觉信息的质量和各种感观接收器提供的大量反馈信息是影响其赛场表现的关键因素。技巧性动作的熟练程度和运动员以往的经验对于运动系统(肌肉)运行的有效性和效率的影响是不可估量的。有天赋的运动员能够稳定而持久地在赛场发挥出色，而且似乎一点都不费力。通过筛选出对运动影响显著的视功能并加以强化训练，进而提高运动员成绩已成为可能。专业人士已经设计出多种视功能训练方案以改善视觉技巧和与视觉相关的运动技巧，并提高视觉信息传递过程中的效率。眼科保健工作者可以采用很多方法来帮助运动员尽量发挥其潜能。通过分析与运动员从事的运动最相关的视功能，可以指导眼科保健工作者选择最适合的矫正模式，如最佳的配戴设计、染色、角膜接触镜参数以及保护方案等。当眼保健工作者选择视觉训练来矫正功能不足或强化与运动相关的视功能时，需要和运动员进行交流，使其积极配舍。结果表明，不但是那些顸尖的运动员能从我们的医疗服务中获益，而且各种人群因为接受训练进而改善了视功能并提高了自身的生活质量。     

Aging,driving and vision

Older people constitute the fastest growing sector of the driving population and are believed to represent a high risk to road safety, given their high crash rate per distance travelled. The crash characteristics of the elderly also differ from those of younger drivers and generally involve multiple vehicles and more complex driving situations. Although the reasons for this deterioration in driving performance are multi‐factorial, the age‐related changes in vision are likely to be a significant factor, given the important role of vision in driving. This paper provides an overview of some of the complex issues associated with older drivers and considers how the aging changes in visual function might impact on driving performance. Particular emphasis is placed on the literature linking vision to driving, with emphasis on more recent research. The implications of this research for driver licensing and self‐regulation of older drivers are also discussed.     

弱视儿童双眼视诱发电位的临床研究

目的　研究弱视对儿童双眼视及VEP双眼总和的影响。以便对弱视儿童双眼间的相互作用及双眼视觉功能异常程度进行大体了解。方法　对 5 4名正常儿童及 41名不伴有斜视的弱视儿童VEP的双眼总和 (VEPBS)进行探讨研究。结果　弱视儿童组的双眼总和低于正常组。尤其是无双眼视的弱视儿童双眼总和明显低于正常对照组 ,并且波形有异常 ,可显示双眼间有抑制。并发现弱视程度与双眼总和VEP反应之间不存在一致性。结论　在不伴有斜视的情况下 ,对弱视儿童进行双眼总和VEP反应测定 ,可以反映弱视仍是损害双眼视功能的重要因素。同时证明视觉诱发电位双眼总和能反映视功能状况 ,对双眼视功能的评价具有一定价值     

重视与体育运动有关的视觉科学研究

体育运动与视觉功能关系密切,不同的体育项目对视觉功能的要求不同.大部分体育项目对视觉的需求都是综合性的,即不仅需要敏锐的视力、立体视、色觉、视野等静态视觉,还需要快速的眼球运动、调节辐辏等动态视觉.优秀运动员必须具备良好的视觉功能,而相关的视觉功能训练可望提高运动成绩.我们应重视并开展体育运动与视觉科学的研究.     

Vision Rehabilitation and Charles Bonnet Syndrome

Purpose: To evaluate the prevalence of visual hallucinations in Charles Bonnet Syndrome (CBS) among patients at a Low Vision Clinic. To determine whether Low Vision Rehabilitation (LVR) intervention results in a decrease of these visual hallucinations. Methods: We surveyed 50 consecutive new patients in a low vision clinic to determine whether they had experienced visual hallucinations consistent with CBS. All patients were: questioned about the presence of visual hallucinations; given an educational handout that described CBS and reassured them of the benign nature of these hallucinations; and administered Folstein's Mini Mental Status Examination (MMSE). During their low vision examination, all patients received low vision aids to improve their visual function. At follow-up patients who had symptoms of CBS were administered a second survey to evaluate whether they had experienced any change in the frequency of their visual hallucinations. Results: Of the 50 patients surveyed, 12 of 50 (24%) had visual hallucinations typical of CBS. 6 of these 12 patients (50%) had daily recurring hallucinations. At mean follow-up of 34.9 +/?30 days, a second survey was administered to 11 of the 12 patients diagnosed with CBS. One patient was lost to follow-up. Three of the 11 patients (27.3%) experienced a decrease in the frequency of their hallucinations by 43.33% +/?30.55%. Eight of 11 patients (72.7%) did not note a change in their symptoms. Conclusions: It is important to include direct questions regarding visual hallucinations in the case history of a low vision examination. LVR may decrease the frequency of CBS hallucinations in some patients. Rehabilitation strategies should include low vision devices that allow for improved visual function and patient education to provide needed reassurance.