title: Influence of ocular wavefront aberrations on axial length elongation in myopic children treated with overnight orthokeratology.
abstract: OBJECTIVE
  To determine ocular optical parameters that affect axial length elongation in myopic children undergoing overnight orthokeratology.
  
  
  METHODS
  Prospective, noncomparative study.
  
  
  METHODS
  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.
  
  
  METHODS
  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 C2(0), 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 C4(0). 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.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan. Electronic address: thiraoka@md.tsukuba.ac.jp.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hiraoka
authors.affiliation: Kakita Eye Clinic, Chiba, Japan.
authors.forename: Tetsuhiko
authors.initials: T
authors.lastname: Kakita
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors.forename: Fumiki
authors.initials: F
authors.lastname: Okamoto
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Oshika
mesh_terms: D058452:Axial Length, Eye / Q000503:physiopathology*; D002648:Child; D019781:Corneal Topography; D057108:Corneal Wavefront Aberration / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology* / Q000628:therapy*; D054158:Orthokeratologic Procedures; D011446:Prospective Studies