The medical indications for, and outcome of scleral contact lens wear in 517 eyes of 343 patients attending a Scleral Contact Lens Clinic during a 5-year period from July 1988 to June 1993 were analysed. Keratoconus was the most common condition requiring scleral lens wear (36.2%), followed by aphakia (18.4%), postpenetrating keratoplasty (12.0%), irregular astigmatism secondary to corneal disease (12.0%), high myopia (12.8%), and ocular surface disorders (6.4%). The main indication was visual (85.8%), whereas therapeutic indications accounted for 8.2% of cases. Seventy-six percent of cases had previously failed with other types of contact lenses. The majority of patients were initially fitted with impression moulded polymethylmethacrylate (PMMA) lenses (90.5%); other scleral lens types included preformed PMMA lenses, preformed high Dk gas-permeable (GP) lenses, and a GP/PMMA hybrid scleral lens design. Initial scleral lens fitting was successful in 93.2% of cases, and 71% remained successful with a mean duration of 11.8 years' follow-up. Complications included corneal vascularisation (13.3% of eyes), episodes of corneal oedema (7.4%), corneal abrasion (3.1%), and giant papillary conjunctivitis (1.7%). In addition to 19 eyes initially fitted with GP lenses, there were 99 eyes initially wearing PMMA lenses that were subsequently refitted with GP scleral lenses.