Age and the amplitude of accommodation measured using dynamic retinoscopy.

PURPOSE: Dynamic retinoscopy (DR) is a procedure for assessing the accommodative response using a standard clinical instrument. The present study compared measurements of the amplitude of accommodation (AA) obtained using this technique with two subjective methods (modified push-down and minus lens). Additionally, the expected ranges for AA when measured by DR were determined.

METHOD: AA was measured in 1298 subjects between 5 and 60 years of age using the three techniques described above. Subjects were grouped into 5-year bins, and a descriptive univariate analysis of the data performed. Goodness-of fit plots were constructed to examine the overall model fit. Centile curves were calculated from the final model.

RESULTS: Mean values of AA obtained using DR were significantly lower than for the two subjective techniques. For the DR findings, no significant change was observed between 5 and 19 years of age (mean AA = 8.3 D) and between 45 and 60 years of age (mean AA = 0.6 D). AA values as a function of age were best fit by the polynomial regression equation: logAA = 1.93 + 0.49(age) - 0.19(age)(2) .

CONCLUSION: Measurements of AA determined using DR are significantly lower than the normative subjective findings published previously. This difference is at least partly due to the depth-of-field of the eye. These norms markedly overestimate accommodative responsivity. DR provides a simple technique for quantifying accommodation in the clinical setting.