title: Corneal refractive therapy gas permeable lenses for the correction of hyperopia after one night of lens wear.
abstract: OBJECTIVE
  To examine the refractive and keratometric response of corneal refractive therapy (CRT) contact lenses for hyperopia (CRT) after a single night of contact lens wear with the goal of reducing hyperopia by +3.50 D.
  
  
  METHODS
  Twenty participants were fitted with a CRT HDS 100 contact lens, in one eye only. The back optic zone radius of the CRT lens was designed to correct 3.50 D of hyperopia. The eyes were randomly selected. The Nikon Auto Refractor was used to measure refractive error. Corneal topography and simulated K readings were measured using the Humphrey Atlas topographer. The lens was subsequently worn overnight, and the lens was assessed the next morning on awakening.
  
  
  RESULTS
  Refractive error changed by 1.50±0.71 D (mean ± SD, range 0.50-2.75 D) immediately after lens removal in the experimental eye. Similarly, there was a change in flat K readings of 0.58±0.62 D with a range of -0.25 to +1.87 D. These results were significantly different from the baseline measurements (P<0.0001).
  
  
  CONCLUSIONS
  The fitting of CRT HDS for hyperopia has a significant effect on corneal shape and refractive error. There was a moderate yet significant steepening of the cornea.
authors.affiliation: Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada. gsorbara@uwaterloo.ca
authors.forename: Luigina
authors.initials: L
authors.lastname: Sorbara
authors.forename: Fenghe
authors.initials: F
authors.lastname: Lu
mesh_terms: D000328:Adult; D003261:Contact Lenses; D005260:Female; D005740:Gases / Q000493:pharmacokinetics*; D006801:Humans; D006956:Hyperopia / Q000503:physiopathology* / Q000534:rehabilitation*; D008297:Male; D054158:Orthokeratologic Procedures / Q000592:standards; D010539:Permeability; D012029:Refraction, Ocular; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D005740:Gases