title: Regular replacement of extended wear rigid gas permeable contact lenses.
abstract: OBJECTIVE
  While the benefits of planned replacement of soft contact lenses have been investigated, the question of whether there are any clinical benefits to planned replacement of rigid gas permeable (RGP) lenses does not appear to have been addressed experimentally. We aimed to determine the benefits of regular replacement of extended wear RGP contact lenses.
  
  
  METHODS
  We conducted a prospective, single-center, controlled, double-masked study of 39 RGP lens wearers. The subjects were divided into two groups and wore extended wear Quantum 2 lenses (Dk = 120) for 12 months. Subjects in Group I replaced lenses every 3 months, whereas those in Group II were not scheduled to replace their lenses. The integrity of the lenses and the ocular responses to lens wear were monitored in both groups every three months.
  
  
  RESULTS
  Compared to lenses worn by subjects in Group I, lenses worn by Group II subjects showed significantly more mucous coating, lens binding, and corneal staining over time (P < 0.05; ANCOVA). There was no difference in microcystic or tarsal conjunctiva response, lens comfort, refractive change, or visual acuity between the two groups.
  
  
  CONCLUSIONS
  We advocate that to maintain optimal lens integrity and ocular health, RGP lenses used for extended wear should be replaced every 3 to 6 months.
authors.affiliation: Department of Optometry and Vision Sciences, UMIST, Manchester, England.
authors.forename: C A
authors.initials: CA
authors.lastname: Woods
authors.forename: N
authors.initials: N
authors.lastname: Efron
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003231:Conjunctivitis / Q000209:etiology / Q000517:prevention & control; D003262:Contact Lenses, Extended-Wear; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D017755:Prosthesis Fitting; D012030:Refractive Errors / Q000503:physiopathology / Q000628:therapy*; D014792:Visual Acuity