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Abstract
PURPOSE: The authors describe a method for estimating the spheric aberration (SA) of the human crystalline lens in vivo. METHODS: This method was based on a comparison of the measured change in contrast sensitivity (delta log (CSF)) of the eye and the calculated change in modulation transfer function of the cornea with undilated and dilated pupils. The method assumes that the total change in visual efficiency (delta log (CSF)) in these two states is caused entirely by the SA of the eye combined with the Stiles-Crawford effect. RESULTS: Data are reported for 20 subjects (age range, 20-56 yr). SA for the whole eye was found to be positive and in the range 0-0.83 D (0-0.80 D using Stiles-Crawford apodization). The SA of the crystalline lens was generally negative and in the range 0 to -0.81 D (0 to -0.78 D using apodization). CONCLUSIONS: The method gives results consistent with previous reports in the literature. Despite potential limitations, the technique offers a new method for estimating the SA of the human crystalline lens in vivo.