Arditi A, Cagenello R
Vision Research Laboratory, Lighthouse Inc., New York, New York 10017.
Invest Ophthalmol Vis Sci. 1993 Jan;34(1):120-9.
To determine boundary values of test-retest reliability and sensitivity to acuity change that are unlikely to be exceeded in any clinical situation, for a popular visual acuity chart (Lighthouse/ETDRS) with three scoring methods; to discuss general methodological issues associated with statistical accuracy of optotype chart testing; and to link measures of test reliability to measures of sensitivity to change.
Five highly practiced subjects were tested using a computer-controlled acuity testing system in a procedure designed to reduce measurement error. Subjects read the computerized chart 156 times, yielding a sample of 78 test-retest comparisons.
Under conditions likely to minimize variability, visual acuity may, with 95% confidence, be ascertained only within +/- 0.1 log units, using this chart with the recommended letter-by-letter scoring. Detecting a significant change in visual acuity requires about +/- 0.14 log units for the same degree of confidence.
These measurements may be viewed as approaching the upper limit of reliability of this letter chart. Reliability probably is considerably less in typical usage.
对于一种具有三种评分方法的常用视力表（灯塔/早期糖尿病性视网膜病变研究组 [ETDRS] 视力表），确定在任何临床情况下都不太可能超过的重测信度和视力变化敏感度的界值；讨论与视标视力表测试统计准确性相关的一般方法学问题；并将测试信度的测量与变化敏感度的测量联系起来。
使用计算机控制的视力测试系统对五名经验丰富的受试者进行测试，该程序旨在减少测量误差。受试者阅读计算机化视力表156次，得到78对重测比较样本。
在可能使变异性最小化的条件下，使用该视力表并采用推荐的逐字母评分法，视力在95%置信度下只能确定在±0.1对数单位范围内。对于相同的置信度，检测视力的显著变化需要约±0.14对数单位。
这些测量结果可被视为接近该字母视力表信度的上限。在典型使用中，信度可能要低得多。
