Does ethnic origin influence the incidence or severity of keratoconus?

Purpose Keratoconus affects all races, yet very little information exists a s to the relative frequency in patients of different ethnic origin. We aime d to establish the incidence and severity of keratoconus in Asian and white patients. Methods The hospital records of the ophthalmology department of a large Mid lands hospital with a catchment population of approximately 900 000 (87% wh ite, 11% Asian, 2% other) were examined retrospectively for the 10 year per iod from 1989 to 1998. Results For the age group 10-44 years the prevalence of keratoconus in Asia ns and whites was 229 and 57 per 100 000 respectively, a relative prevalenc e of 4 to 1. The incidence of keratoconus in the same age group was 19.6 an d 4.5 per 100 DOD per year respectively, a relative incidence of 4.4 to 1. Asians were significantly younger at presentation compared with whites (mea n 22.3 +/- 6.5 vs 26.5 +/- 8.5 years, p < 0.0001). A first corneal graft wa s carried out on 14% of the Asian and 15% of the white patients. Of those h aving grafts, Asians were significantly younger than white patients at the time of diagnosis (mean 19.1 +/- 4.8 vs 25.7 +/- 7.3 years, p = 0.005) and at operation (mean 21.4 +/- 5.0 vs 28.7 +/- 7.7 years, p = 0.004). The inte rval from diagnosis to operation, though shorter for Asians, was not signif icantly different (mean 1.8 +/- 1.4 vs 2.5 +/- 1.7 years, p = 0.2). Conclusion The results show previously unrecognised racial differences in t he hospital presentation of keratoconus in the UK. Compared with white pati ents, Asians have a fourfold increase in incidence, are younger at presenta tion and require corneal grafting at an earlier age.