We assessed repeatability and intercorrelations of five standard vision tests in subjects with normal vision.
Seventy-eight subjects (aged 21 to 68 years) completed five measurements each of high- and low-contrast visual acuity, near visual acuity and contrast sensitivity (Pelli-Robson chart).
Except for correlations between high- and low-contrast visual acuity (r = 0.78), intercorrelations between tests were low to moderate (r < 0.5). For each measure, variability for the group was about one line on the chart (one triplet for the Pelli-Robson chart) and the minimum variability for an individual subject was about one third of this. On average, 1 to 2 lines can be expected to be lost over the normal lifespan on each test. Variability in responses did not increase significantly with age for any test.
The criterion for judging change on commonly used clinical vision tests is about one line for subjects over a wide age range.
Centre for Eye Research, School of Optometry, Queensland University of Technology, Brisbane, Australia
Received December 30, 1999; revision received May 22, 2000.
Queensland University of Technology
Centre for Eye Research, School of Optometry
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