Clinical detection of unilateral keratoconus

PURPOSE: To determine the incidence of true unilateral keratoconus on the basis of computerised corneal topography in a group with clinically diagnosed unilateral keratoconus. METHODS: Retrospective review of 295 patients with keratoconus identified 51 patients with a provisional diagnosis of unilateral keratoconus. Thirty-one of these patients were re-examined clinically and 21 patients met the criteria for a clinical diagnosis of unilateral keratoconus. Computerised corneal topographic analysis (Tomey TMS) was then performed. RESULTS: In a group of 21 patients with clinically diagnosed unilateral keratoconus, computerised corneal topographic analysis identified 14 (67%) patients with bilateral keratoconus and seven (33%) patients with true unilateral keratoconus. Contact lens wear had no significant influence (P=0.76) on the topographical diagnosis of keratoconus in the clinically unaffected fellow eye. The estimated incidence of true unilateral keratoconus in the cohort of 295 patients was 4%. CONCLUSIONS: Computerised corneal topography improves sensitivity in detection of true unilateral keratoconus.