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。     

规范视力的检测和统计方法

中心视力 (简称视力 )是衡量视觉器官功能状态、观察眼部疾病严重程度、评估治疗效果和预后的重要主观检测指标 ,在新技术、新疗法的疗效评价中起着重要作用[1] 。在既往的眼科文献报道中 ,内容涉及视力的文章较多 ,但是不仅少有作者明确说明采用何种视力表和方法对视力进行检测和统计 ,而且常出现使用不正确统计学方法的错误 ,从而导致文献之间无法进行交流和比较。因此 ,眼科临床规范检测、记录和统计视力的方法实属必要。一、正确选用视力表目前国内外眼科临床使用的多种视力表均存在缺陷 ,如每两行间视标大小的变化不等 ,导致每行视力变…     

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。     

低视力对数视力表的研制

目的 :研制一种适合我国眼科临床使用的低视力对数视力表。方法 :根据Baily Lovie的LogMAR视力表和我国标准对数视力表的设计标准和原理设计 ,1分视角为 1.0视力 ,视标的增率为 10 10 ,视标的间距和行距与我国标准视力表相同 ,E字母设备 ,每行视标个数与Baily Lovie的视力表一致。为了与低视力分级标准一致 ,采用小数记录。结果和结论 :低视力对数视力表 ,设计合理 ,检查低视力的范围大 ,将应用于我国眼科临床     

拥挤Kay图片视力表在学龄前儿童视力筛查中的应用

目的：采用拥挤Kay图片视力表检测学龄前儿童视力,并和标准对数视力表检测结果进行比较,探讨2种视力表检测结果是否具有一致性,以补充不能完成标准对数视力表检测的学龄前儿童的视力筛查。方法：前瞻性自身对照研究。于2021年1─5月随机选取济南市章丘区某幼儿园152名学龄前儿童进行全面眼科筛查,分别使用拥挤Kay图片视力表及标准对数视力表对其进行视力检测,并采用Wilcoxon检验进行2种视力差异性的比较,Spearman秩相关分析及Bland-Altman分析进行相关性及一致性分析。结果：152名儿童参与筛查,其中129名儿童屈光状态正常且能配合2种视力表检测。129名儿童中男74名,女55名,年龄为（52.3±7.0）个月;拥挤Kay图片测得LogMAR视力为0.10（0.09,0.10）,标准对数视力表视力为0.10（0.10,0.22）;2种视力检查方法有较好的相关性（r=0.436,P<0.001）,拥挤Kay视力表检测结果略高于标准视力表约0.04 LogMAR,差异有统计学意义（Z=-6.124,P<0.001）,Bland-Altman散点图显示98.4%的点均在一致性范围内;参与筛查儿童Kay图片视力检查配合度更高（χ2=18.007,P<0.001）。不同月龄拥挤Kay图片视力检测结果差异有统计学意义（H=13.791,P=0.003）,随年龄增长,视力呈递增趋势。结论：拥挤Kay图片视力表用于学龄前儿童视力检测,患儿配合程度高,其结果与标准对数视力表相比有较好的一致性,但Kay图片视力表所检查的视力结果高于标准视力表约0.04 LogMAR,在参考视力结果时应相应调整视力标准。     

我国4种眼科学术期刊中视力相关问题的统计与分析

目的 了解《中华眼科杂志》《中国实用眼科杂志》《中华眼底病杂志》《眼视光学杂志》4种期刊中有关视力方面问题的统计.方法 仔细阅读2008年在这4种期刊中刊出的所有论文,记录每一篇论文的特征,包括是否提及视力、是否以视力作为结果、使用的视力表类型、视力检查细节、远近视力、视力矫正方式、视力记录法、视力的描述性统计等,采用Excel 2003软件对数据进行分类、整理、归纳和求百分比.结果 2008年这4种期刊共发表论文1111篇,提及视力的有476篇,以视力为结果的有237篇.在这237篇中,51篇提到其所使用的视力表类型,其中国际标准视力表占43.1%,标准对数视力表占29.4%;155篇提到了视力矫正方式,以最佳矫正为主;213篇在论文中体现了其所使用的视力记录法,小数记录法占75.1%,5分记录法占10.1%;216篇论文对视力进行了描述性统计,对视力进行分级的占66.7%,以均数±标准差表示的占24.5%.结论 国内眼科学术期刊在书写视力检查细节方面,特别是对视力数据的描述性统计方面还存在较大问题.加强我国眼科医生的眼视光学基础知识培训迫在眉睫,同时相关期刊编辑也需重视对该方面问题的审读.     

国家视力表的标准化问题

视力表在招生、招工、普查及眼科临床和科研中是非常重要而又十分常用的一个工具。迄今为止,视力表的设计已越来越趋向成熟,各国在视力表设计的核心内容方面基本趋向标准化。但人们在视力表的选择、设计和应用方面仍有一些困惑,笔者仅就国际上的视力表和我国国家标准对数视力表的发展历史、视力表设计的核心内容以及目前视力表使用中存在的问题进行述评,以避免在视力表选择和应用中存在的误区,使之更好地应用于视力普查、眼科临床和科研等各领域。     

标准近视力表再版说明和视力国标的商榷

标准近视力表于1956年印制发行,得到全国同道的认可,至今已多次印刷共50余万册。由于中央卫生部于1989年公布了国家的视力表设计标准(GB11533-89),故标准近视力表的设计标准亦应根据新的标准进行修版。在修版中发现了一些学术性问题,谈点自己的看法。一、标准近视力表的再版说明1955年发表的《关于标准近视力表》中指出,远近两种视力表的设计应当采用相同的标准,所查结果方可互相对比为眼科临床尤其对眼屈光不正作出快速的初步诊断。现在国家已为远视力表的设计制定了统一标准,因此标准近视力表亦应按照国家标准进行修版。国家公布的视力表标准共有5项指标。①1视角为正常视力,②三横等长的E 字为视标,③     

多功能视力测试箱

多功能视力测试箱山东省莱芜市医院眼科刘玉珉，李钟实目前视力检查用的视力表一般是单张视力表或后面加有照明灯箱，这种单张视力表只限于成人或儿童单独使用，而且视标的排列是固定的，数量少，易于记忆，影响视力检查准确性。视力表固定高度一般以表中１．０一行与被检...     

新对数视力表的研制

眼科临床工作中,需要一个简便易行,测量相对准确的视力表.鉴于国际标准视力表,存在一些缺点,谬天荣制定的对数视力表,使视力测量工作又前进了一步,但仍存在一些缺点——它在视力定量上特别在经过一段时间后视力变化的定量上存在缺点.这种视力变化常以行数得失作估     

The dependency of logMAR visual acuity measurements on chart design and scoring rule.

BACKGROUND: Visual acuity, increasingly measured using a logarithm of the minimum angle of resolution (logMAR) chart, is the "gold standard" by which the outcomes of the vast majority of clinical trials or interventions are judged. To allow comparison of results across studies, it is important that different charts provide equivalent results. METHODS: In a first experiment, we compared corrected visual acuity measurements from four different logMAR charts (Bailey-Lovie, ETDRS, Regan, and Waterloo). In a second experiment we compared unaided visual acuity scored using a psychometric function with the more clinical by-letter scoring. RESULTS: Experiment 1 showed significantly better visual acuity using the Regan chart compared with the other three charts, and further investigation suggested that this could be due to the font type used. Repeatability data from experiment 2 indicated that no extra repeatability was gained when using psychometric methods compared with the far simpler and quicker by-letter scoring. CONCLUSIONS: When comparing findings between studies, the type of chart and the scoring method used may have a significant effect on the results obtained and should therefore be taken into consideration. Also, the additional time and effort demanded for determining a psychometric function for single readings of the Regan visual acuity chart is not rewarded with improved repeatability.     

Some remarks on the precision of visual acuity measurements

BACKGROUND: Visual acuity measurements are used to determine the course of diseases, treatment outcomes, consequences of accidents, and the occupational ability of a patient. The fact, that visual acuity depends both on visual function as well as on the circumstances of examination, is often understood more intuitively than explicitly. Precision and accuracy of visual acuity measurements must be kept in mind, and occasionally need to be quantified and statistically evaluated, to avoid clinical errors. METHODS: Factors influencing acuity measurements are analyzed. Using appropriate examples the precision of acuity measurements is evaluated and quantified with standard vision test charts and threshold or staircase procedures. Limits of confidence and limits of tolerance are described for the statistical evaluation of consecutive visual acuity measurements. RESULTS AND CONCLUSIONS: The statistical evaluation of standard procedures is relatively time consuming, as 3 to 4 standardized measurements are needed on first examination and on follow-up. Threshold and staircase methods, however provide more feasible data, due to the examination technique. All evaluation procedures described here, can only be applied with logMAR acuity readings.     

视力表的历史、现状与发展趋势

视觉是人类最重要的感觉之一。视锐度反映了视觉系统辨别空间细节的能力,是临床实践中最常用的视功能评估指标。视力表是使用最广的视锐度测量工具。笔者回顾了国内外视力表的发展历程,简述了早期糖尿病视网膜病变治疗研究视力表和标准对数视力表的设计原理和计分规则。由于传统视力表自身的精度限制,其在视力普查和儿童青少年近视防控工作中的局限性也日益凸显,电子视力表代替传统视力表正逐渐成为趋势。笔者分析了当前不同电子视力表的硬件特性、软件算法逻辑和测量结果,发现显示屏的分辨率和尺寸、程序的测量和计分规则等多种参数设置的不统一可能会造成不同设备测量视力的结果不具有可比性。研发规范化的新型电子视力表势在必行。     

Visual acuity and its measurement

Despite its critical importance to our daily life, the most common measurement of visual function, visual acuity, is a relatively crude and narrow one testing only a small portion of the broad range of visual functions. Visual acuity is the measurement of the ability to discriminate two stimuli separated in space at high contrast relative to the background. Clinically, this is measured by asking the subject to discriminate letters of known visual angle. The visual acuity is represented as the reciprocal of the minimal angle of resolution (the smallest letters resolved) at a given distance and at high contrast. Other measurements of visual acuity also exist, including Vernier acuity. Newer charts, such as the ETDRS chart, use letters of equal recognition difficulty and use the log of the minimal angle of resolution; these charts have significant advantages over the old Snellen-type charts. This article reviews visual measurements in children and in patients with low vision, and it reviews factors affecting visual acuity, such as pupil size, refractive error, media opacities, and pharmacologic agents.     

Landolt C and snellen e acuity: differences in strabismus amblyopia?

BACKGROUND: Assessment of visual acuity depends on the optotypes used for measurement. The ability to recognize different optotypes differs even if their critical details appear under the same visual angle. Since optotypes are evaluated on individuals with good visual acuity and without eye disorders, differences in the lower visual acuity range cannot be excluded. In this study, visual acuity measured with the Snellen E was compared to the Landolt C acuity. PATIENTS AND METHODS: 100 patients (age 8 - 90 years, median 60.5 years) with various eye disorders, among them 39 with amblyopia due to strabismus, and 13 healthy volunteers were tested. Charts with the Snellen E and the Landolt C (Precision Vision) which mimic the ETDRS charts were used to assess visual acuity. Three out of 5 optotypes per line had to be correctly identified, while wrong answers were monitored. In the group of patients, the eyes with the lower visual acuity, and the right eyes of the healthy subjects, were evaluated. RESULTS: Differences between Landolt C acuity (LR) and Snellen E acuity (SE) were small. The mean decimal values for LR and SE were 0.25 and 0.29 in the entire group and 0.14 and 0.16 for the eyes with strabismus amblyopia. The mean difference between LR and SE was 0.55 lines in the entire group and 0.55 lines for the eyes with strabismus amblyopia, with higher values of SE in both groups. The results of the other groups were similar with only small differences between LR and SE. CONCLUSION: Using the charts described, there was only a slight overestimation of visual acuity by the Snellen E compared to the Landolt C, even in strabismus amblyopia. Small differences in the lower visual acuity range have to be considered.     

SOME STATISTICAL CONCEPTS IN THE ANALYSIS OF VISION AND VISUAL ACUITY

As conventionally recorded, visual acuity data constitute an ordinal scale of measurement. An investigation of four different clinical samples shows that visual acuity is not normally distributed amongst these populations. Furthermore, acuity is often measured on charts which, by the inherent restriction of the stimulus size, have the effect of truncating the upper limit of the scale producing, in statistical terms, an incomplete distribution. The distribution of acuity for each sample is found to be adequately described in terms of the equation: F(x) = Ax alpha (T - x) beta, where F(x) is the cumulative distribution of the statistical population, T is the truncation level (known), x is the Snellen decimal acuity (known) and A, alpha and beta are parameters. Alternative analytical procedures based upon this model, which overcome these limitations, are discussed.     

The use of accurate visual acuity measurements in clinical anti-cataract formulation trials

A standardized visual acuity technique is presented for use in anti-cataract drug trials. Ferris Logmar charts were used in repeatability studies of vision, visual acuity and pinhole visual acuity measurements for twenty normal subjects (mean (+/- SD) age 64 +/- 6.3 years). Visual acuity measurements were shown to be the most repeatable and thought to be the most suitable for monitoring cataract progression. Repeated visual acuity measurements were made on 29 cataractous eyes of 15 subjects (mean (+/- SD) age 67.8 +/- 7.2 years). A Logmar score change of 0.1 (one line) was shown to be a statistically significant change. This value can be used in statistical analyses of drug efficacy. The normal data gives a mean Logmar visual acuity of 1.15 (Snellen equivalent 6/5). This indicates the inadequacy of using 6/6 as a norm value for visual acuity, even for older patients. As the possibility of reversal of cataract theoretically exists in the early stages of cortical and capsular cataracts, patients with small amounts of these types of cataract are ideal patients for anti-cataract formulation trials. The normal visual acuity results indicate that the inclusion criteria for clinical trials can include patients with cataracts with visual acuity as good as 6/6.     

学龄前儿童常用视力表的研究进展

学龄前期(3-6岁)是视觉发育的关键时期，及早发现并治疗学龄前儿童视觉问题至关重要。视力表是筛查儿童视觉问题的重要工具，国内常采用标准对数视力表和儿童图形视力表，而国外则常用Lea、HOTV和ETDRS视力表。已经有很多研究报道了这三种视力表在儿童视力检查中的可测性、可重复性及诊断视觉相关问题的敏感性。然而，在国内这三种视力表的应用较为有限，本文就这三种视力表的设计原理、临床中的应用及各自的特点进行综述，以便更好地了解它们在学龄前儿童中的适用性和局限性，从而为未来视力检查方法的选择和改进提供参考。     

The slope of the psychometric function for Bailey-Lovie letter charts: defocus effects and implications for modeling letter-by-letter scores.

BACKGROUND: Visual acuity measurement often results in an imprecise endpoint because subjects correctly identify some but not all of the letters on one or more size levels on a letter chart. The extent of this transition zone from seeing to nonseeing can be described by probit size, which is calculated by performing Probit Analysis on letter chart data. There has been no previous research into the effects of optical defocus on letter chart probit size. METHODS: We tested 18 young visually normal subjects monocularly during three different defocus conditions: best spectacle correction (zero defocus) and +1.00 D and +2.00 D additions. Stimuli were Bailey-Lovie-style logarithm of the minimum angle of resolution (log MAR) letter charts constructed with a 0.05 logMAR size progression between size levels. Frequency of seeing data from these charts were used to calculate probit size. RESULTS: There were statistically significant effects of optical defocus on mean probit size. After Monte Carlo correction for bias, we believe that true mean values for probit size are about 0.07 logMAR for well-corrected subjects and up to 0.12 logMAR with optical defocus. CONCLUSION: The smaller probit size for well-corrected subjects should correspond to a sharper logMAR visual acuity endpoint and less intrasubject variability in logMAR acuity than for subjects with a larger probit size (optical defocus). Our modeling shows that these different probit sizes can also significantly affect letter-by-letter visual acuity scoring.     

An evaluation of the M&S technologies smart system II for visual acuity measurement in young visually-normal adults.

PURPOSE: To compare visual acuity measures obtained with the M&S Technologies Smart System II (SSII) and the revised Early Treatment of Diabetic Retinopathy Study (ETDRS) charts in terms of accuracy and test-retest repeatability. METHODS: Monocular visual acuities were taken in 57 young, visually normal adults on two separate visits in which both the SSII system and the ETDRS charts were tested in random order by two masked examiners. The eye to be tested throughout was chosen randomly at the initial visit. Measurements were made through an optimal phoropter correction, determined by a noncycloplegic refraction for a 10-foot distance. Both charts were presented at 10 feet, and were matched closely for luminance. RESULTS: The mean visual acuity in the group was -0.16 log minimum angle of resolution (MAR) for the ETDRS chart and -0.18 log MAR for the SSII, a small but statistically significant difference. A 95% confidence interval for the mean difference in visual acuity between the two charts was -0.033 log MAR to -0.003 log MAR. The test-retest repeatability was not significantly different in the two tests. The 95% limits of agreement for test-retest repeatability were -0.13 log MAR to +0.17 log MAR for the SSII and -0.12 log MAR to +0.13 log MAR for the ETDRS charts. CONCLUSIONS: The SSII can provide an accurate (mean difference<0.033 log MAR) and repeatable alternative to the ETDRS charts for visual acuity measurement in young, visually normal, well-corrected individuals.