Comparing the amplitude of accommodation determined objectively and subjectively.

The purpose of this study was to determine if differences exist between subjective and objective methods of measuring the amplitude of accommodation. In a double-masked study on 57 patients, ages 6 to 35 years, 2 examiners measured the amplitude, 1 using the subjective push-up method and the other using a modified form of dynamic retinoscopy. Significant differences among the findings occurred (p < 0.001), the amplitude of accommodation being on the average 2.7 D higher with dynamic retinoscopy. The amplitudes as determined subjectively for each eye were highly correlated (gamma = 0.92), as were the objective findings (gamma = 0.85). Four other examiners also used this method of dynamic retinoscopy to determine the amplitude of accommodation on 43 patients, ages 11 to 39 years. For three examiners, the average amplitude of accommodation measured objectively was statistically similar to that measured subjectively. For the other examiner, the objective findings were on the average 1.19 D higher than the subjective findings. This study suggests that this modified form of dynamic retinoscopy can give consistent results, although different for some examiners than the traditional push-up method when determining the amplitude of accommodation.