Bak-Nielsen S, et al. - Candidates diagnosed with keratoconus in the National Danish Patient Register 1977–2015 were estimated to know the prevalence of keratoconus and the annual incidence rate of keratoconus in Denmark 1995–2015. They noted an increment in the annual incidence rate from 1.24 per 100,000 person-years in 2003 to 3.83 per 100,000 in 2011 with an average incidence rate (2011–2015) of 3.60 per 100,000 person-years. In the National Patient Register 1977–2015, the prevalence of diagnosed keratoconus was 44 per 100,000 persons.