Influence of Ocular Wavefront Aberrations on Axial Length Elongation in Myopic Children Treated with Overnight Orthokeratology

• Published in: Ophthalmology (Rochester, Minn.) Vol. 122; no. 1; pp. 93 - 100
• Main Authors: Hiraoka, Takahiro, MD, Kakita, Tetsuhiko, MD, Okamoto, Fumiki, MD, Oshika, Tetsuro, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 2015
• Subjects: Axial Length, Eye - physiopathology; Child; Corneal Topography; Corneal Wavefront Aberration - physiopathology; Female; Follow-Up Studies; Humans; Male; Myopia - physiopathology; Myopia - therapy; Ophthalmology; Orthokeratologic Procedures; Prospective Studies; SD; D; diopters; root mean square; RMS; logarithm of the minimum angle of resolution; logMAR; standard deviation
• ISSN: 0161-6420; 1549-4713
• DOI: 10.1016/j.ophtha.2014.07.042

Purpose To determine ocular optical parameters that affect axial length elongation in myopic children undergoing overnight orthokeratology. Design Prospective, noncomparative study. Participants Fifty-nine subjects who met the inclusion criteria were enrolled in this study. Methods Axial length and ocular wavefront aberration were assessed before and 1 year after the start of orthokeratology. Corneal topography was performed, and then corneal multifocality was calculated for a 4-mm pupil. After evaluating simple correlations between axial elongation and optical parameters, multiple linear regression analysis was performed to identify explanatory variables with a statistically significant contribution to axial elongation. Main Outcome Measures Axial length and ocular wavefront aberration before and 1 year after the start of orthokeratology. Results Fifty-five subjects completed the 1-year follow-up examinations. At baseline, their age ranged from 7.2 to 12.0 years. The manifest spherical equivalent refractive error ranged from −3.50 to −0.75 diopters. The mean axial length significantly increased from 24.20 mm at baseline to 24.43 mm 1 year after treatment. The axial elongation showed significant simple correlations with the change in C20 , change in second-order aberration, change in coma-like aberration, change in spherical-like aberration, change in total higher-order aberrations, change in corneal multifocality, baseline age, and baseline spherical equivalent refractive error, but not C40 . Multiple linear regression analysis showed that the change in coma-like aberration was the most relevant variable. Conclusions Asymmetric corneal shapes, rather than concentric and radially symmetric shapes, have a considerable effect on retardation of axial elongation, suggesting that the inhibitory effect of orthokeratology on myopia progression is caused by mechanisms other than the reduction in peripheral hyperopic defocus.