Corneal abrasion associated with contact lens correction of keratoconus--a retrospective study.

BACKGROUND: Corneal abrasion is a frequently encountered complication of contact lens wear, but we are not aware of any previous study of relative frequency comparing keratoconic to nonkeratoconic patients.

METHODS: We retrospectively studied the incidence of corneal abrasion during 2 months of contact lens practice.

RESULTS: 784 contact lens-related patient visits (494 total patients); patients were assessed by 3 optometrists and 13 abrasions (11 patients) were diagnosed. Only the total number of individual patients and the first abrasion for each patient were statistically considered; the overall frequency of abrasion was therefore 11/494 (2.3%)/2 months. The frequency of abrasion was 5/68 (7.4%)/2 months for keratoconic patients and 6/426 (1.4%)/2 months for nonkeratoconic patients and this difference was significant (chi 2 test: p < 0.01). Among nonkeratoconic patients, the frequency of abrasion was 2/246 (0.8%)/2 months with hydrogel contact lens wear and 4/178 (2.2%)/2 months with rigid gas permeable (RGP) contact lens wear, but this difference did not achieve significance (chi 2 test: p = 0.10). IDENTIFIED RISK FACTORS INCLUDED: Contact lens wear; a torn lens and chemical keratitis for hydrogel lens wearers; an adherent "bound" lens and keratoconus for rigid lens wearers.

CONCLUSION: Keratoconus appears to be a statistically significant risk factor for corneal abrasion among contact lens wearers.