title: Factors preventing myopia progression with orthokeratology correction.
abstract: OBJECTIVE
  To examine which baseline measurements constitute predictive factors for axial length growth over 2 years in children wearing orthokeratology contact lenses (OK) and single-vision spectacles (SV).
  
  
  METHODS
  Sixty-one children were prospectively assigned to wear either OK (n = 31) or SV (n = 30) for 2 years. The primary outcome measure (dependent variable) was axial length change at 2 years relative to baseline. Other measurements (independent variables) were age, age of myopia onset, gender, myopia progression 2 years before baseline and baseline myopia, anterior chamber depth, corneal power and shape (p value), and iris and pupil diameters as well as parental refraction. The contribution of all independent variables to the 2-year change in axial length was assessed using univariate and multivariate regression analyses.
  
  
  RESULTS
  After univariate analyses, smaller increases in axial length were found in the OK group compared to the SV group in children who were older, had earlier onset of myopia, were female, had lower rate of myopia progression before baseline, had less myopia at baseline, had longer anterior chamber depth, had greater corneal power, had more prolate corneal shape, had larger iris diameter, had larger pupil sizes, and had lower levels of parental myopia (all p < 0.05). In multivariate analyses, older age and greater corneal power were associated with smaller increases in axial length in the OK group (both p < 0.05), whereas in SV wearers, smaller iris diameter was associated with smaller increases in axial length (p = 0.021).
  
  
  CONCLUSIONS
  Orthokeratology is a successful treatment option in controlling axial elongation compared to SV in children of older age, had earlier onset of myopia, were female, had lower rate of myopia progression before baseline, had lower myopia at baseline, had longer anterior chamber depth, had greater corneal power, had more prolate corneal shape, had larger iris and pupil diameters, and had lower levels of parental myopia.
authors.affiliation: *OD, PhD, FAAO †MSc, PhD, FAAO ‡PhD, FCOptom, FAAO §MD, PhD Menicon Co., Ltd (Madrid Office) (JS-R); Clínica Oftalmológica Novovision (CV-C, RG-O); and Universidad Europea de Madrid (CV-C), Madrid, Spain; and School of Life and Health Sciences (BG), Aston University, Aston Triangle, Birmingham, United Kingdom.
authors.forename: Jacinto
authors.initials: J
authors.lastname: Santodomingo-Rubido
authors.forename: César
authors.initials: C
authors.lastname: Villa-Collar
authors.forename: Bernard
authors.initials: B
authors.lastname: Gilmartin
authors.forename: Ramón
authors.initials: R
authors.lastname: Gutiérrez-Ortega
mesh_terms: D058452:Axial Length, Eye / Q000503:physiopathology; D002648:Child; D003261:Contact Lenses; D003315:Cornea / Q000503:physiopathology; D018450:Disease Progression; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000517:prevention & control*; D054158:Orthokeratologic Procedures; D012029:Refraction, Ocular / Q000502:physiology