Keratoconus Prevalence Among High School Students in New Zealand

Purpose: To determine the prevalence of keratoconus among high school students in Wellington, New Zealand. Method: The Wellington Keratoconus Study was a population-based prospective cross-sectional study of 2 cohorts in Wellington: cohort 1 (year 9 students, mean age 13.9 years) and cohort 2 (year 11 students, mean age 15.5 years). Results: A total of 1916 students with a mean age of 14.6 years participated from 20 schools in the region. Keratoconus was found in 1:191 (0.52%) participants overall and in 1:45 (2.25%) Maori participants. Pentacam mean Kmax of 48.7 diopters (D) (cohort 1, 45.5 D; cohort 2, 49.9 D), thinnest pachymetry of 494.05 mu m (cohort 1, 479.0 mu m; cohort 2, 499.5 mu m), posterior elevation at the thinnest point of 23.4 (cohort 1, 15.2; cohort 2, 26.6), Belin/Ambrosio enhanced ectasia display overall D value of 4.30 (cohort 1, 3.2; cohort 2, 4.7) were noted in participants with keratoconus. In those with keratoconus, 8 of 10 had visual impairment of 0.2 Logarithm of the Minimum Angle of Resolution (LogMAR) or worse in the better eye; 7 of 10 did not use visual aids; 7 of 10 had atopy; and 6 of 10 were from a low school decile. In those without keratoconus, 43.8% had atopy. Conclusions: Keratoconus may affect up to 1 in 191 New Zealand adolescents and 1 in 45 Maori adolescents. Keratoconus appeared to be associated with Maori ethnicity, atopy, lower school decile, visual impairment, and the underutilization of visual aids. Nationwide screening programs may have a role in reducing the burden of disease associated with keratoconus.