Prevalence of Keratoconus in Persons with down Syndrome in a National Registry in Norway

Keratoconus is an eye condition with distinctive corneal characteristics, including thinning and a conical shape of the cornea. Keratoconus was previously considered rare; however, in recent studies, a prevalence of 0.2% to 0.3% has been reported1 and, in some studies, an even higher prevalence. An association of keratoconus with Down syndrome has been shown,2,3 although the exact reason remains unknown. In some studies, investigators have reported frequencies of keratoconus in persons with Down syndrome of 0% to 71%2-5; however, most have been limited by small sample sizes and biased patient selection. The aim of the present study was to estimate the prevalence of keratoconus among persons with Down syndrome in Norway