Comparison of optical quality metrics to predict subjective quality of vision after laser in situ keratomileusis

Abstract

To compare wavefront-derived metrics to predict subjective quality of vision after laser in situ keratomileusis (LASIK) for myopia. Department of Ophthalmology, Goethe University, Frankfurt am Main, Germany. One month postoperatively, wavefront sensing was performed and overall subjective quality of vision assessed under 3 lighting conditions (photopic, high mesopic, low mesopic) with a questionnaire. Four wavefront-error representations were computed for a pupil diameter of 6.0 mm and individual physiological pupil diameters at 0.4 lux: (1) the visual Strehl ratio based on optical transfer function (VSOTF), (2) the root-mean-square (RMS) value of Zernike orders 2 to 5 (total RMS), (3) higher-order aberration (HOA) RMS, and (4) a wavefront-error breakdown into the RMS of lower-order aberrations, coma, spherical aberration, and remaining HOA. The impact of the postoperative wavefront error on subjective quality of vision was calculated using linear regression analysis. Fifty-six eyes (29 patients) were included. The ability of wavefront error-derived metrics to predict subjective quality of vision was limited. The VSOTF, calculated for the best-corrected eye, showed the highest predictability. Calculation of wavefront error for individual physiological pupil diameters did not improve predictive ability of the metrics. Eyes with a high theoretical retinal-image quality had a high subjective quality of vision, and eyes with a low subjective quality of vision had a low theoretical image quality. Postoperative wavefront error had limited influence on the subjective quality of vision. Postoperative retinal image quality should be kept as high as possible to provide good subjective quality of vision.