Objective Amplitude of Accommodation Computed from Optical Quality Metrics Applied to Wavefront Outcomes

PURPOSE: We studied the accuracy and precision of 32 objective wavefront methods for finding the amplitude of accommodation obtained in 180 eyes. METHODS: Ocular accommodation was stimulated with 0.5 D steps in target vergence spanning the full range of accommodation for each subject. Subjective monocular amplitude of accommodation was measured using two clinical methods, using negative lenses and with a custom Badal optometer. RESULTS Both subjective methods gave similar results. Results obtained from the Badal optometer where used to test the accuracy of the objective methods. All objective methods showed lower amplitude of accommodation that the subjective ones by an amount that varied from 0.2 to 1.1 D depending on the method. The precision in this prediction also varied between subjects, with an average standard error of the mean of 0.1 D that decreased with age. CONCLUSIONS: Depth of field increases subjective of amplitude of accommodation overestimating the objective amplitude obtained with all the metrics used. The change in the negative direction of spherical aberration during accommodation increases the amplitude of accommodation by an amount that varies with age. (J Optom 2009;2:223-234 ©2009 Spanish Council of Optometry)