title: Effect of hyperopic photorefractive keratectomy on corneal sensitivity: a longitudinal study.
abstract: OBJECTIVE
  To investigate corneal sensitivity after photorefractive keratectomy (PRK) for low hyperopia, as measured with a non-invasive stimulus.
  
  
  METHODS
  Two experimental groups were recruited: a control group of 17 patients (mean age 61.65 years) who underwent no treatment, and a PRK group of 11 patients (mean age 58.64 years) who underwent one of three attempted hyperopic corrections: +2.00 D (two patients), +3.00 D (four patients), +4.00 D (five patients). Corneal sensitivity was assessed centrally and peripherally, at temporal, medial, and inferior locations, approximately 1 mm from the limbus, using the Non-Contact Corneal Aesthesiometer (NCCA). Measurements were taken at each location for the control group and at preoperative, and postoperative weeks 1 and 2, 1, 3, and 6 months for the PRK group.
  
  
  RESULTS
  Comparison of control and PRK groups (preoperative sensation threshold) (t-test): central P=.715, temporal P=.719, medial P=.943, inferior P= .920. Comparison of longitudinal changes in PRK group (one-way ANOVA): central P=.612, temporal P=.997, medial P=.981, inferior P=.993.
  
  
  CONCLUSIONS
  Using the Non-Contact Corneal Aesthesiometer, no significant difference was found between the control and PRK groups for preoperative sensation thresholds, and no significant change in corneal sensitivity was found between any of the test time periods at any of the four corneal test locations for the PRK group.
authors.affiliation: Department of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom. MurphyPJ@cardiff.ac.uk
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Murphy
authors.forename: David P S
authors.initials: DP
authors.lastname: O'Brart
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Stephenson
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Oliver
authors.forename: Sudi
authors.initials: S
authors.lastname: Patel
authors.forename: John
authors.initials: J
authors.lastname: Marshall
mesh_terms: D000328:Adult; D000368:Aged; D003315:Cornea / Q000502:physiology* / Q000601:surgery; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000503:physiopathology / Q000601:surgery*; D054018:Lasers, Excimer; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D018903:Photorefractive Keratectomy; D012677:Sensation / Q000502:physiology*; D012684:Sensory Thresholds