title: Medical applications of scleral contact lenses: 2. Gas-permeable scleral contact lenses.
abstract: The indications and outcome of the wear of gas-permeable (GP) scleral contact lenses in 118 eyes of 85 patients attending a Scleral Contact Lens Clinic during a 5-year period from July 1988 to June 1993 were analysed. Ninety-nine eyes (83.9%) were originally fitted with PMMA lenses and were subsequently changed to GP lenses, whereas 19 (16.1%) were fitted with GP lenses from the outset. The mean duration of GP scleral lens wear was 15.3 months, with a range between 3 and 58 months. The indications for refitting the cases previously wearing PMMA scleral lenses with GP material were related to problems of chronic hypoxia. Thirty-three eyes (26.8%) had previous episodes of corneal oedema, and of the 27 that had a minimum of 3 months' follow-up, none experienced further episodes of oedema. Of the 32 eyes (26%) that had developed corneal vascularisation associated with PMMA scleral lens wear, two eyes were noted to have significant vessel regression after a period of GP wear, whereas in the remainder of cases, vessels remained static and nonprogressive. Thirty additional eyes (24.2%) experienced inadequate wear times associated with discomfort, and in these eyes the change to GP scleral lenses produced a statistically significant reduction in the inability to wear lenses beyond 4 h (p < 0.05).
authors.affiliation: Singapore National Eye Centre.
authors.forename: D T
authors.initials: DT
authors.lastname: Tan
authors.forename: K W
authors.initials: KW
authors.lastname: Pullum
authors.forename: R J
authors.initials: RJ
authors.lastname: Buckley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000869:Anterior Eye Segment / Q000473:pathology; D002648:Child; D003261:Contact Lenses / Q000009:adverse effects; D005128:Eye Diseases / Q000175:diagnosis / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017755:Prosthesis Fitting; D012590:Sclera; D016896:Treatment Outcome; D014792:Visual Acuity