To describe the prevalence and systemic associations of keratoconus in young adults in Perth, Western Australia.
Cross-sectional study PARTICIPANTS: 1,259 participants, aged 20 years old METHODS: The Raine Study is a multi-generational, longitudinal cohort study based in Perth, Western Australia. This study represents a cross-sectional analysis of the birth cohort, when they returned for their 20-year follow-up. Participants underwent a detailed ophthalmic examination, including visual acuity assessment and Scheimpflug imaging using the Pentacam (Oculus, Germany) and completed a health questionnaire. Keratoconus was defined as a BAD-D score of ≥2.6 in either eye based on Pentacam imaging.
MAIN OUTCOME MEASURES
Prevalence of keratoconus in this cohort.
Of the 1,259 participants, 50.8% were female, and 85.7% were Caucasian. Fifteen participants had keratoconus in at least one eye, giving a prevalence of 1.2% (95% confidence interval, CI [0.7, 1.9]), or 1 in 84. There was a significant difference in the best corrected visual acuity (0.01 vs -0.05 logMAR, p=0.007), cylinder (1.25 vs 0.25 diopters cylinder, p<0.001) and spherical equivalent (-1.42 vs -0.50 diopters sphere, p=0.02) on objective refraction, mean keratometry of the steep meridian (45.19 vs 43.76 diopters, p<0.001) and mean corneal thickness at the thinnest point (475 vs 536μm, p<0.001) between those with and without keratoconus. Keratoconus was associated with regular cigarette smoking (38.5% vs 14.6%, p=0.04), but no association with sex, race, body mass index, use of spectacles or contact lenses, history of allergic eye disease or pregnancy was observed.
The prevalence of keratoconus in our Australian population-based study of 20-year-old adults was 1.2% (95% CI [0.7, 1.9]), or 1 in 84, which is one of the highest reported in the world. This has important implications for screening individuals at a younger age so treatment can be initiated before disease progression.