Corneal higher-order aberrations induced by overnight orthokeratology

PURPOSE: To evaluate corneal higher-order aberrations induced by overnight orthokeratology for myopia. DESIGN: Prospective, noncomparative, consecutive, interventional case series. METHODS: A prospective study was conducted in 64 eyes of 39 patients with overnight orthokeratology for myopia, who were followed up for at least 3 months and attained uncorrected visual acuity of 20/20 or better. Corneal height data were obtained with computerized videokeratography (TMS-2N, Tomey), and wavefront aberration was derived using Zernike polynomials. Higher-order aberrations of the cornea were calculated for 3- and 6-mm pupils. RESULTS: Orthokeratology significantly reduced manifest refraction from -2.60 +/- 1.13 (mean +/- SD) diopters to -0.17 +/- -0.31 diopters (P < .0001, paired t test). Root-mean-square (RMS) of third-order (coma-like) aberrations significantly increased by orthokeratology for both 3-mm (P < .0001, paired t test) and 6-mm (P < .0001) pupils. Fourth-order RMS (spherical-like) aberrations increased significantly by the treatment for both 3-mm (P < .0001) and 6-mm (P < .0001) pupils. Vertical coma significantly changed from positive to negative for both 3-mm (P = .0323) and 6-mm (P < .0001) pupils. Horizontal coma significantly increased to the positive direction for both 3-mm (P < .0001) and 6-mm (P < .0001) pupils. Increases in the third- and fourth-order RMS showed significant positive correlations with the amount of myopic correction for 3-mm (Pearson correlation coefficient, r = .452, P = .0001 for third-order RMS, r = .381, P = .0017 for fourth-order RMS) and 6-mm (r = .499, P < .0001, r = .455, P = .0001) pupils. CONCLUSIONS: Corneal higher-order aberrations significantly increased, even in clinically successful orthokeratology cases. The increases in the higher-order aberrations correlated with the magnitude of myopic correction. (c) 2005 by Elsevier Inc. All rights reserved.