Study of accommodative facility testing reliability.

This study was designed to evaluate the reliability of the accommodative facility testing procedure. Sixty-six subjects, ages 8 to 12 years, were studied over 3 consecutive weeks. Monocular and binocular accommodative facility, using plus and minus 2 D lenses, was performed each week. Statistical analysis showed a significant mean increase in cycles per minute (cpm) between initial and subsequent testing periods, both monocular and binocular, for all subjects as a group. The most dramatic increases were observed among subjects who scored below established norms initially. To evaluate the effect of test-retest variability on the subject's pass/fail status the first test period results were used to categorize the subjects as pass or fail. Passing was greater than or equal to 11 cpm monocularly, greater than or equal to 8 cpm binocularly. Failing was less than 1, cpm monocularly, less than 8 cpm binocularly. Subsequent test results were compared to the initial testing results to determine the pass/fail reliability of the testing procedure. No significant differences were found to occur in either the monocular or binocular "pass" category. However, a significant increase in the passing rate from the initial to the subsequent testing periods for both the monocular and binocular facility rates was observed in the "fail" category. Dividing the fail group into "low-fails" (less than 6 cpm monocularly, less than 3 cpm binocularly) and "high-fails" (greater than 6 less than 11 cpm monocularly, greater than 3 less than 8 cpm binocularly) indicated this significant increase was principally in the high-fail group.