Comparison of wavefront-optimized refraction determined pre- and post-cycloplegia in individuals with Down syndrome

Abstract

Purpose: To compare metric-optimized refractions determined from wavefront aberration measures with the COAS-HD wavefront aberrometer pre- and post-dilation and the resultant visual acuity through each refraction in participants with Down syndrome. Methods: Twenty-one adults (mean age = 31 ± 9 years) and 21 children (mean age = 11 ± 4 years) with Down syndrome had wavefront aberrations measured pre- and post-dilation. A mathematical program applied a large range of sphero-cylindrical refractions to the uncorrected wavefront error for each eye and calculated the resultant visual Strehl ratio (VSX). The refraction providing the single best value of VSX was identified from both the pre- and post-dilation analyses. Participants returned for a second visit for in-office tests of logMAR visual acuity while viewing through pre- and post-dilation-optimized refractions. For analysis, refractions were converted to M, J0, and J45 vectors, and the total dioptric difference between pre- and post-dilation refractions was calculated. Visual acuity pre- and post-dilation was compared using the Wilcoxon signed-rank test. Results: The estimated median total dioptric difference (Q1, Q3) between pre- and post-dilation refractions was 0.66D (0.47, 1.11) in the right and 0.80D (0.44, 1.12) in the left eyes of children and 0.90D (0.41, 1.43) and 0.74D (0.42, 1.32) in the right and left eyes of adults. The M-value was significantly more hyperopic in both children and adults post-dilation (P=0.0014). There was no significant difference in the distance visual acuity OD, OS, or OU between the pre- and post-dilation acuity measures in adults and children (P>0.14). Conclusions: Dilation status significantly affected the metric-optimized refractive outcomes, but did not significantly affect visual acuity outcomes in adults and children with Down syndrome. While the median difference between pre- and post-dilation measures was in the range of 0.66–0.90 D, some individual differences reached multiple diopters, suggesting that dilation upon an initial visit is still important for a subset of individuals.