title: A randomized trial of the effects of rigid contact lenses on myopia progression.
abstract: OBJECTIVE
  To compare the effects of rigid gas-permeable contact lenses (RGPs) and soft contact lenses (SCLs) on myopia progression in children.
  
  
  METHODS
  We randomly assigned 116 subjects to wear RGPs or SCLs. Subjects underwent cycloplegic autorefraction, keratometry, and A-scan ultrasonographic axial length measurements at each annual visit. All analyses were conducted according to the original randomization assignment. The primary outcome measure was the 3-year change in spherical equivalent cycloplegic autorefraction.
  
  
  RESULTS
  The mean +/- SD spherical equivalent cycloplegic refractive error progressed -1.56 +/- 0.95 diopters (D) for RGP wearers and -2.19 +/- 0.89 D for the SCL wearers during the 3 years of the study (analysis of covariance [ANCOVA], P<.001). The axial growth of the eyes was not significantly different between treatment groups (ANCOVA, P = .57). The steep corneal meridian of the RGP wearers steepened 0.62 +/- 0.60 D, and that of the SCL wearers steepened 0.88 +/- 0.57 D during the 3 years (ANCOVA, P = .01).
  
  
  CONCLUSIONS
  The RGP wearers' myopia progressed less than that of the SCL wearers. The corneal curvature of the SCL wearers steepened more than that of the RGP wearers, but the axial growth was not significantly different between the groups. Most refractive error treatment effect was limited to the first year of the trial. The results of the study provide information for eye care practitioners to share with their patients, but they do not indicate that RGPs should be prescribed primarily for myopia control.
authors.affiliation: The Ohio State University College of Optometry, Columbus 43210-1240, USA. walline.1@osu.edu
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Walline
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Jones
authors.forename: Donald O
authors.initials: DO
authors.lastname: Mutti
authors.forename: Karla
authors.initials: K
authors.lastname: Zadnik
mesh_terms: D002648:Child; D003261:Contact Lenses; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology* / Q000628:therapy*; D012029:Refraction, Ocular; D016037:Single-Blind Method; D014792:Visual Acuity