Mesopic Contrast Sensitivity and Ocular Higher-Order Aberrations after Overnight Orthokeratology - 20/08/11

Doi : 10.1016/j.ajo.2007.11.021

Takahiro Hiraoka ^a,^⁎ , Chikako Okamoto ^a, Yuko Ishii ^a, Tomonori Takahira ^a, Tetsuhiko Kakita ^b, Tetsuro Oshika ^a
^a Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan
^b Kakita Eye Clinic, Chiba, Japan.

Inquiries to Takahiro Hiraoka, Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575 Japan

Résumé

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.

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