A COMPARISON OF THE RELIABILITY AND VALIDITY OF VISUAL ACUITY TEST TARGETS.
NAVAL SCHOOL OF AVIATION MEDICINE PENSACOLA FLA
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The validity of five targets for testing visual acuity was determined through the correlation of test results of each target with the Grow chart scores. In addition, the testretest reliability of all six tests was studied. The targets under consideration were The Sight Screener, a New London letter target, two Randolph Field letter targets, and an adaptation of the Ortho-Rater checkerboard type target. One hundred subjects were employed. Acuity scores, obtained in Snellen equivalents, were translated into logunits to facilitate statistical analysis. Additional systems were essayed for scoring each of the Randolph Field tests. Statistical analyses consisted in 1 deriving test-retest reliability coefficients and coefficients of intercorrelation among the test scores by means of product-moment correlation, 2 determining the significance of the differences between test and retest mean scores, 3 determining the significance of the differences between mean scores on the various tests by the t tests, and 4 obtaining the conventional measures of dispersion and statistical reliability. Results of the statistical analyses and clinical observations of the examiners relating to each test are presented. Author