Mesopic contrast sensitivity and ocular higher-order aberrations after overnight orthokeratology

PURPOSE: To investigate mesopic contrast sensitivity and night driving ability in eyes undergoing overnight orthokeratology, and to analyze the relationship among mesopic contrast sensitivity, ocular higher,order aberrations, and myopic correction. DESIGN: Prospective, noncomparative, consecutive case series. METHODS: In 44 eyes of 22 subjects (mean age +/- standard deviation [SD], 24.0 +/- 3.2 years) with orthokeratology, ocular aberrations and mesopic contrast sensitivity were determined before and three months after commencement of the procedure. Mean spherical equivalent refraction +/- SD was -2.34 +/- 0.99 diopters at baseline. Mesopic contrast sensitivity with and without glare was assessed using the Mesotest II (Oculus, Wetzlar, Germany). RESULTS: Orthokeratology significantly reduced the log mesopic contrast sensitivity from 0.25 +/- 0.08 to 0.08 +/- 0.10 without glare (P < .0001, Wilcoxon) and from 0.21 +/- 0.11 to 0.07 +/- 0.10 with glare (P < .0001). The proportion of eyes that fulfilled the German standard recommendation level for night driving was 36%. The induced changes in log mesopic contrast sensitivity showed significant negative correlation with the changes in third,order (r = -0.490, P = .0013 without glare; r = -0.362, P = .0177 with glare; Spearman rank correlation coefficient) and fourth,order root mean square (r = -0.586, P = .0001 and r = -0.306, P = .0450, respectively). Furthermore, significant correlation was found between the amount of myopic correction and the induced changes in log mesopic contrast sensitivity (r -0.442, P = .0038 without glare; r = -0.464, P = .0024 with glare). The induced changes in higher, order aberrations significantly correlated with the amount of myopic correction (P < .0001, Pearson correlation coefficient). CONCLUSIONS: Mesopic contrast sensitivity after overnight orthokeratology is deteriorated significantly as ocular higher,order aberrations increase, and these changes depend on the amount of myopic correction.