title: Spectacle and contact lens wearing six years after radial keratotomy in the Prospective Evaluation of Radial Keratotomy Study.
abstract: BACKGROUND
  Patients in the Prospective Evaluation of Radial Keratotomy (PERK) Study stated that a major reason for obtaining radial keratotomy was to see without dependence on corrective lenses. The authors examined lens-wearing patterns 6 years after surgery.
  
  
  METHODS
  Of the 435 patients in the PERK Study, the authors analyzed the responses of 328 (75.4%) who elected to have surgery on both eyes, who completed a questionnaire at 6 years, and for whom visual acuity and cycloplegic refraction were available.
  
  
  RESULTS
  Sixty-four percent (106/167) of patients younger than 40 years of age and 38% (64/161) of patients older than 40 years of age wore no lenses for distance or near vision. The proportion of time lenses were worn increased with age for those who wore them for close work only (from 18% younger than 40 years of age to 25% older than 40 years of age) and decreased with age for those who wore them for distance only (from 41% to 27%). The authors examined the visual acuity and refractive error criteria for patients to be free of distance lenses. Of the 359 patients who saw 20/20 or better uncorrected in one or both eyes, 77% (n = 198) wore no distance correction, whereas of the 53 patients who saw 20/25 to 20/40 in both eyes or their best eye, only 34% (n = 18) wore no distance correction. Of the 72 patients with a residual refractive error of +/- 0.50 diopters (D) in both eyes, 85% (n = 61) wore no distance correction, whereas of the 87 patients with +/- 1.00 D in both eyes, only 39% (n = 34) wore no distance correction. Of the 328 patients, 60% (n = 197) were highly satisfied with the results of surgery, and satisfaction was primarily predicted by having a visual acuity 20/20 or better in at least one eye and not wearing spectacles for distance vision. Before surgery, 57% of patients reported worrying about their eyesight and 47% reported restrictions in activities because of their eyes; these rates dropped to 31% and 9%, respectively, at 6 years. Of the 328 patients, 74% (n = 243) said their preoperative goals were completely met and 94% (n = 308) said they would have radial keratotomy again.
  
  
  CONCLUSIONS
  The use of 20/40 uncorrected visual acuity and a residual refractive error of +/- 1.00 D were insensitive criteria for evaluating distance spectacle independence. The ability to function without lenses increased substantially only when patients had an uncorrected visual acuity of 20/20 or better in at least one eye, and a refractive error within +/- 0.50 D.
authors.affiliation: University of California, School of Public Health, Los Angeles.
authors.forename: L B
authors.initials: LB
authors.lastname: Bourque
authors.forename: M J
authors.initials: MJ
authors.lastname: Lynn
authors.forename: G O
authors.initials: GO
authors.lastname: Waring
authors.forename: C
authors.initials: C
authors.lastname: Cartwright
mesh_terms: D000328:Adult; D000368:Aged; D003261:Contact Lenses / Q000706:statistics & numerical data*; D005069:Evaluation Studies as Topic; D005139:Eyeglasses / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007646:Keratotomy, Radial / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery; D017060:Patient Satisfaction; D011446:Prospective Studies; D012029:Refraction, Ocular; D011795:Surveys and Questionnaires; D014792:Visual Acuity