title: Excimer laser photorefractive keratectomy for hyperopia: 7.5-year follow-up.
abstract: OBJECTIVE
  To report the results of a long-term prospective study to evaluate refractive stability and safety of hyperopic photorefractive keratectomy (H-PRK).
  
  
  METHODS
  Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom.
  
  
  METHODS
  Twenty-one patients (49%) (40 eyes) of cohort of 43 patients who participated in 1 of the first clinical trials of H-PRK were assessed at a mean follow-up of 90.7 months (range 62 to 106 months). The H-PRK was performed using a Summit Technology Apex Plus Excimer laser (Summit Technology, Inc.). The mean preoperative spherical equivalent refraction (SEQ) was +4.70 diopters (D) (range +2.00 to +7.50 D). Patients were allocated to 1 of 4 treatment groups based on their preoperative refraction and received 1 of the following spherical corrections: +1.50 D, +3.00 D, +4.50 D, or +6.00 D.
  
  
  RESULTS
  At 7.5 years, the refractive correction remained stable with a mean difference in SEQ between 1 year and 7.5 years of +0.28 D. The mean manifest SEQ was +0.83 D (range +5.00 to -3.00 D). Sixty-seven percent of eyes having corrections of +1.50 D and +3.00 D were within +/-1.00 D of the predicted correction. Predictability was poorer with +4.50 D and +6.00 D corrections, with 40% of eyes within +/-1.00 D of that expected. An improvement in uncorrected near acuity was achieved in 35 eyes (87.5%), and 35 eyes (87.5%) showed an improvement in uncorrected distance acuity from preoperative levels. Best spectacle-corrected visual acuity (BSCVA) was unchanged or improved from preoperative values in 25 eyes (62.5%). Three eyes (8%) lost 2 lines of Snellen BSCVA, which in 2 cases was attributable to cataract formation. A peripheral ring of haze, 6.5 mm in diameter, appeared in most eyes. Its intensity was greatest at 6 months and then diminished with time. In 10 eyes (25%), remnants of the haze ring were evident at 7.5 years and subepithelial iron rings, 6.5 mm in diameter were evident in 26 eyes (70%). No patient complained of night-vision problems and no eye developed ectasia.
  
  
  CONCLUSIONS
  In H-PRK, refractive stability achieved at 1 year was maintained up to 7.5 years with no evidence of hyperopic shift, diurnal fluctuation, or late regression. Peripheral corneal haze decreased with time but was still evident in a number of eyes at the last follow-up visit.
authors.affiliation: Department of Ophthalmology, St. Thomas' Hospital, London SE1 7EH, UK. davidobrart@aol.com
authors.forename: David P S
authors.initials: DP
authors.lastname: O'Brart
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Patsoura
authors.forename: Philip
authors.initials: P
authors.lastname: Jaycock
authors.forename: Madavan
authors.initials: M
authors.lastname: Rajan
authors.forename: John
authors.initials: J
authors.lastname: Marshall
mesh_terms: D000328:Adult; D000368:Aged; D003315:Cornea / Q000503:physiopathology; D019781:Corneal Topography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006956:Hyperopia / Q000503:physiopathology / Q000601:surgery*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D018903:Photorefractive Keratectomy; D011183:Postoperative Complications; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult