title: Discontinuation of orthokeratology on eyeball elongation (DOEE).
abstract: OBJECTIVE
  To evaluate and compare changes in axial elongation, over a 14-month period, in subjects who discontinued and then resumed ortho-k lens wear with those who continued to wear their lenses or spectacles following a 2-year myopia control study.
  
  
  METHODS
  This single masked, prospective study recruited subjects who had just completed a 2-year myopia control study. Ortho-k subjects were classified as Group OKc, in which subjects continued ortho-k lens wear for the duration of the study; or Group OKd in which subjects discontinued lens wear for seven months and wore single-vision spectacles (Phase I) and then resumed ortho-k lens wear for another seven months (Phase II). Spectacle-wearing control subjects from the initial myopia control study continued wearing spectacles as control subjects. Axial lengths were measured at scheduled visits using the IOLMaster.
  
  
  RESULTS
  Thirteen, 16, and 15 Control, OKc, and OKd subjects, aged 8-14 years, respectively completed the study. Significant increase in axial elongation was found in OKd subjects only in Phase I but not in Phase II. On resuming lens wear, in Phase II, the rate of axial elongation was no longer significantly different from those of the Control or OKc subjects.
  
  
  CONCLUSIONS
  Stopping ortho-k lens wear at or before the age of 14 years led to a more rapid increase in axial length; comparable to those wearing spectacles during the initial 2-year myopia control study, but greater than the Control and OKc group in this study. Axial elongation slowed again with resumed lens wear after six months.
authors.affiliation: School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China. Electronic address: pauline.cho@polyu.edu.
authors.forename: P
authors.initials: P
authors.lastname: Cho
authors.affiliation: School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: S W
authors.initials: SW
authors.lastname: Cheung
mesh_terms: D000293:Adolescent; D058452:Axial Length, Eye / Q000503:physiopathology*; D002648:Child; D003261:Contact Lenses; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000628:therapy*; D054158:Orthokeratologic Procedures; D011446:Prospective Studies; D016037:Single-Blind Method; D028761:Withholding Treatment
keywords: Axial elongation; Discontinuation; Myopia control; Orthokeratology