title: Contact lens wear after photorefractive keratectomy: comparison between rigid gas permeable and soft contact lenses.
abstract: OBJECTIVE
  To determine if rigid gas permeable (RGP) or soft contact lenses can be successfully worn after photorefractive keratectomy (PRK) to correct residual refractive errors.
  
  
  METHODS
  Patients with residual stable ametropia after PRK were fit with RGP or soft lenses. Manifest refraction, corneal topography, and keratometry were performed, and post-PRK corneal haze was graded during the study visits. Contact lens fit characteristics and comfort were assessed. Lens centration, visual quality, and ocular surface status were graded, and visual acuity with contact lenses was charted.
  
  
  RESULTS
  Eighteen patients were recruited for RGP lens fitting. The mean refractive error post-PRK was +0.80 D +/- 2.03 (range: -3.50 to+3.00 D). The mean contact lens power was -3.90 D +/- 2.03 (range: 0 to -7.00 D), and the mean contact lens base curve was 7.88 mm +/-0.16. A significant positive tear film at the site of the central ablation was noted, contributing to excessive minus lens power in all cases. Despite mild to moderate lens instability and de-centration, 14 patients reported excellent visual quality with the lenses, and pre-PRK best-corrected acuity was achieved in all patients. Twenty-five percent (4 of 16) of the patients were able to wear the lenses all day. Eleven patients were recruited for soft contact lens fitting-five from the RGP trial. The mean refractive error post-PRK was -0.64 D +/- 2.01 (range: -3.50 to +1.75D). The mean contact lens power was -0.60 D +/- 2.07 (range: -3.75 to +2.5 D), and the mean contact lens base curve was 8.33 mm +/- 0.42. Eight patients were corrected with lenses to their pre-PRK best-corrected acuity, and nine patients reported excellent visual quality with the lenses. All the patients had excellent lens centration. Thirty-six percent (four of 11) of patients were wearing the lenses all day.
  
  
  CONCLUSIONS
  Fitting RGP lenses after PRK results in good visual acuity but may be associated with mild to moderate lens instability and decentration. Soft contact lens fitting also results in good visual acuity. Soft lenses were better tolerated by the subjects in our study because of improved lens centration and stability.
authors.affiliation: Singapore National Eye Center, Singapore.
authors.forename: L
authors.initials: L
authors.lastname: Lim
authors.forename: K L
authors.initials: KL
authors.lastname: Siow
authors.forename: J S
authors.initials: JS
authors.lastname: Chong
authors.forename: D T
authors.initials: DT
authors.lastname: Tan
mesh_terms: D000328:Adult; D003261:Contact Lenses; D003263:Contact Lenses, Hydrophilic; D005260:Female; D005740:Gases; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D010539:Permeability; D018903:Photorefractive Keratectomy; D011182:Postoperative Care; D011184:Postoperative Period; D017755:Prosthesis Fitting; D012030:Refractive Errors / Q000503:physiopathology / Q000628:therapy; D014792:Visual Acuity
chemical_list: D005740:Gases