Number of incident cases of the main eye diseases of ageing in the UK Biobank cohort, projected over a 25-year period from time of recruitment

Objectives To estimate the number of new cases of age-related macular degeneration, cataract and glaucoma accruing in the UK Biobank cohort, over a period of 25 years from time of recruitment. Our secondary objective was to assess the statistical power of nested case–control studies of these eye diseases. We aimed to provide quantitative information relevant to UK Biobank’s eye disease case ascertainment efforts and to the potential for UK Biobank-based research into the causes of eye disease. Methods We constructed a Markov discrete-time state transition model to simulate the population dynamics of the eye disorders within the UK Biobank cohort, using prevalence data from population-based epidemiological studies to derive incidence, and Office for National Statistics data on mortality and migration overseas. Results By 2023, >900 new cases of each of ‘wet’ (neovascular) and ‘dry’ age-related macular degeneration, >1200 cases of primary open angle glaucoma and almost 15 000 cases of cataracts are expected to have accrued in the subcohort of 68 500 participants who had ocular assessment at baseline, with around seven times as many cases of each disease in the whole cohort of 500 000 participants. These predicted incident case numbers generate good or substantial statistical power for a range of nested case–control studies of potential genetic, lifestyle and environmental determinants of disease. Conclusions Over the next few years, UK Biobank is expected to generate sufficient numbers of new cases for statistically well-powered studies of the determinants of the major causes of sight loss: age-related macular degeneration, vision-impairing cataract and glaucoma.