title: Overnight orthokeratology: visual and corneal changes.
abstract: OBJECTIVE
  To achieve an optimal fit with reverse geometry Contex OK lenses and to determine a time course for and the stability of visual and corneal changes in achieving maximal refractive, corneal curvature, and corneal thickness changes after overnight wear of OK B and D series lenses.
  
  
  METHODS
  This investigation was conducted under an Food and Drug Administration IDE G000059. Both eyes of 10 subjects were fitted with the lenses, and uncorrected visual acuity, refractive correction, contrast sensitivity, corneal curvature, and corneal thickness were measured at baseline and at 1 day, 1week, 1 month, and 3 months after lenses were worn. Except for baseline, data were collected at four different times during the day, immediately following lens removal and 4, 8, and 12 hours after lens removal.
  
  
  RESULTS
  The results from eight subjects showed that uncorrected visual acuity, refractive correction, contrast sensitivity, and corneal curvature all changed significantly (P=0.01) overnight. By the end of 1 week, all corneal and visual changes had reached a maximal level and remained fairly stable during the day. These changes were sustained at 3 months. The epithelial thickness data from four subjects showed that the corneal epithelial thickness was reduced by approximately 19 microm after 3 months of lens wear.
  
  
  CONCLUSIONS
  Successful fitting of OK B and D series lenses requires a thorough understanding of the lens-cornea relationship. Full effect of overnight orthokeratology is achieved by the end of 1 week. The visual and corneal changes remain stable for all waking hours of the day and allow patients to enjoy excellent device-free vision (20/20).
authors.affiliation: Borish Center for Ophthalmic Research, School of Optometry, Indiana University, Bloomington, IN 47401, USA. sonip@indiana.edu
authors.forename: P Sarita
authors.initials: PS
authors.lastname: Soni
authors.forename: Tracy T
authors.initials: TT
authors.lastname: Nguyen
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Bonanno
mesh_terms: D000328:Adult; D003261:Contact Lenses; D015350:Contrast Sensitivity / Q000502:physiology; D003315:Cornea / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000628:therapy*; D017755:Prosthesis Fitting; D012029:Refraction, Ocular / Q000502:physiology; D012826:Silicone Elastomers; D014792:Visual Acuity / Q000502:physiology*
chemical_list: D012826:Silicone Elastomers