title: Short-term changes in ocular biometry and refraction after discontinuation of long-term orthokeratology.
abstract: OBJECTIVE
  To assess refractive and biometric changes 1 week after discontinuation of lens wear in subjects who had been wearing orthokeratology (OK) contact lenses for 2 years.
  
  
  METHODS
  Twenty-nine subjects aged 6 to 12 years and with myopia of -0.75 to -4.00 diopters (D) and astigmatism of ≤1.00 D participated in the study. Measurements of axial length and anterior chamber depth (Zeiss IOLMaster), corneal power and shape, and cycloplegic refraction were taken 1 week after discontinuation and compared with those at baseline and after 24 months of lens wear.
  
  
  RESULTS
  A hyperopic shift was found at 24 months relative to baseline in spherical equivalent refractive error (+1.86±1.01 D), followed by a myopic shift at 1 week relative to 24 months (-1.93±0.92 D) (both P<0.001). Longer axial lengths were found at 24 months and 1 week in comparison to baseline (0.47±0.18 and 0.51±0.18 mm, respectively) (both P<0.001). The increase in axial length at 1 week relative to 24 months was statistically significant (0.04±0.06 mm; P=0.006). Anterior chamber depth did not change significantly over time (P=0.31). Significant differences were found between 24 months and 1 week relative to baseline and between 1-week and 24-month visits in mean corneal power (-1.68±0.80, -0.44±0.32, and 1.23±0.70 D, respectively) (all P≤0.001). Refractive change at 1 week in comparison to 24 months strongly correlated with changes in corneal power (r=-0.88; P<0.001) but not with axial length changes (r=-0.09; P=0.66). Corneal shape changed significantly between the baseline and 1-week visits (0.15±0.10 D; P<0.001). Corneal shape changed from a prolate to a more oblate corneal shape at the 24-month and 1-week visits in comparison to baseline (both P≤0.02) but did not change significantly between 24 months and 1 week (P=0.06).
  
  
  CONCLUSIONS
  The effects of long-term OK on ocular biometry and refraction are still present after 1-week discontinuation of lens wear. Refractive change after discontinuation of long-term OK is primarily attributed to the recovery of corneal shape and not to an increase in the axial length.
authors: Clínica Oftalmológica Novovision (C.V-C., R.G-O.), Madrid, Spain; Universidad Europea de Madrid (C.V-C.), Madrid, Spain; School of Life and Health Sciences (B.G.), Aston University, Birmingham, United Kingdom; and Menicon Co., Ltd (J.S-R.), Madrid, Spain.
authors: Jacinto
authors: J
authors: Santodomingo-Rubido
authors: César
authors: C
authors: Villa-Collar
authors: Bernard
authors: B
authors: Gilmartin
authors: Ramón
authors: R
authors: Gutiérrez-Ortega
mesh_terms: D000867:Anterior Chamber / Q000473:pathology; D001251:Astigmatism / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D058452:Axial Length, Eye / Q000473:pathology; D001699:Biometry; D002648:Child; D019781:Corneal Topography; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D054158:Orthokeratologic Procedures; D012029:Refraction, Ocular / Q000502:physiology