title: Management of pellucid marginal corneal degeneration with rigid gas permeable contact lenses.
abstract: OBJECTIVE
  To study the clinical performance of rigid gas permeable contact lenses (RGPCL) in patients with pellucid marginal corneal degeneration (PMCD).
  
  
  METHODS
  This retrospective study consisted of 15 patients with clinical PMCD, confirmed by videokeratography (TMS-1, Computed Anatomy, Inc., New York, NY). Information collected from the medical records included patient demographic data, uncorrected visual acuity, refraction, best-corrected spectacle visual acuity, and topographic details, including kerotometry. Twenty-seven of 30 eyes were subjected to several contact lens trials using polymethylmethacrylate (PMMA) contact lenses, using a systematic and consistent approach. After successful contact lens trials, data regarding number of trials, trial time, final contact lens choice parameters, and best-corrected contact lens visual acuity were noted for each patient. During follow-up, visual acuity with RGPCLs, lens fit, and average wearing time were noted.
  
  
  RESULTS
  Fifteen patients (30 eyes) with typically inferiorly located pellucid marginal corneal degeneration were included in this study. There were 12 men and 3 women, with a mean age of 39.73 years. Twenty-seven eyes of 15 patients were identified as subjects for multiple contact lens trials, and 24 (88.8%) eyes were successfully fitted with RGPCLs. Best-corrected visual acuity of 6/12 or better with spectacles was achieved in 14 (46.66%) eyes. The average astigmatism was -8.56D, and a majority of the patients with PMCD who were in the contact lens trial had an against-the-rule astigmatism (63.3%). The mean trial time for attempted eyes (i.e., patients with PMCD who successfully underwent the contact lens trials) was 77.7 minutes, and the number of trials required to finalize the choice of contact lenses ranged between 2 and 7. The median base curve for RGP lenses was 7.57, and median diameter was 10.00 mm. Best-corrected visual acuity of 6/12 or better with the final contact lens was achieved in 95.4% of the subjects. After an average follow-up of 22.91 months, one patient was lost to follow-up, and 2 eyes required discontinuation of the contact lenses. The average wearing time among the contact lens wearers at their last follow-up visits was 9.58 hours. Final visual acuity of 6/12 or better was observed in 77.3% of eyes at the end of 22.91 months.
  
  
  CONCLUSIONS
  Large-diameter RGPCLs are better tolerated and lead to significant improvement in visual acuity in inferior PMCD.
authors.affiliation: Bausch & Lomb Contact Lens Center, L.V. Prasad Eye Institute, Hyderabad, India. viswanadhbk@yahoo.com
authors.forename: Viswanadh B
authors.initials: VB
authors.lastname: Kompella
authors.forename: Murali K
authors.initials: MK
authors.lastname: Aasuri
authors.forename: Gullapalli N
authors.initials: GN
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D000328:Adult; D003261:Contact Lenses; D003317:Corneal Dystrophies, Hereditary / Q000628:therapy*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D010539:Permeability; D019904:Polymethyl Methacrylate; D017755:Prosthesis Fitting; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity
chemical_list: D019904:Polymethyl Methacrylate; D010100:Oxygen