title: Visual quality differences between orthokeratology and LASIK to compensate low-moderate myopia.
abstract: OBJECTIVE
  To assess the differences in visual performance between orthokeratology (ortho-k) and laser in situ keratomileusis (LASIK) for the treatment of low-to-moderate myopia.
  
  
  METHODS
  An adaptive optics visual simulator (Imagine Eyes) was used to simulate the wavefront aberration patterns induced by ortho-k and LASIK for low and moderate myopia on 10 healthy eyes. Visual acuity (VA) at 100%, 50%, and 10% contrast levels and contrast sensitivity (CS) at 10, 20 and 25 cycles per degree (cpd) were then measured for 3- and 6-mm pupil sizes.
  
  
  RESULTS
  Differences in VA for 3-mm pupil diameter were not found between ortho-k and LASIK. For 6-mm pupil size, LASIK provided significantly better VA values than ortho-k at 50% and 10% contrast levels for low myopia correction (P = 0.002 and P = 0.001, respectively) and at all contrast levels for moderate myopia correction (P = 0.04 at 100%, P < 0.0001 for 50% and 10% contrast levels). For 3-mm pupil size, differences in CS were not significant between both techniques for low myopia correction and were only significant at 25 cpd (P = 0.03) for moderate myopia correction. For 6-mm pupil diameter, LASIK provided better CS than ortho-k for 20 and 25 cpd for low myopia (P = 0.02 and P = 0.01, respectively) and at all spatial frequencies for moderate myopia (P = 0.02 for 10 cpd and P < 0.0001 for 20 and 25 cpd).
  
  
  CONCLUSIONS
  The results in this study suggest that LASIK provides better visual quality outcomes than ortho-k for the treatment of low-to-moderate myopia.
authors.affiliation: Optics Department, Faculty of Physics, University of Valencia, Valencia, Spain. david.madrid@uv.es
authors.forename: David
authors.initials: D
authors.lastname: Madrid-Costa
authors.forename: Santiago
authors.initials: S
authors.lastname: García-Lázaro
authors.forename: César
authors.initials: C
authors.lastname: Albarrán-Diego
authors.forename: Teresa
authors.initials: T
authors.lastname: Ferrer-Blasco
authors.forename: Robert
authors.initials: R
authors.lastname: Montés-Micó
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015350:Contrast Sensitivity / Q000502:physiology; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D054158:Orthokeratologic Procedures; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult