Cataract in the 21st century: Lessons from previous epidemiologic research

Background: Cataract surgery is currently the most commonly performed ophthalmic procedure in Australia. The purpose of this paper is to review Australian data on cataract prevalence and risk factors and to project potential future demand for cataract services. Methods: Age-and gender-specific cataract prevalence data from the Melbourne Visual Impairment Project (VIP) and the Blue Mountains Eye Study (BMES) were applied to population estimates from the Australian Bureau of Statistics. Published cataract risk factor data from the two studies were reviewed. Results: Although the projected number of cataracts varies substantially based on the definition used, the relative number of cataracts will double over the next 50 years due to the aging of the population. Risk factors for cortical cataract identified in both the VIP and the BMES included female gender, sunlight exposure and myopia. Concordant findings for nuclear cataract included female gender, brown irides, cigarette smoking and myopia. The only risk factor for posterior subcapsular cataract (PSC) that was identified in both studies was myopia. Some of the discrepant findings between the two studies included alcohol intake, diabetes and medication use. Discussion: These data suggest that supply and demand for cataract surgery must be considered and managed to maintain the current level of cataract surgery delivery as the number of people with cataract increases at a proportionately greater rate than the total population. The supply of cataract surgical services could be increased through an increase in the number of ophthalmologists, an increase in the efficiency with which cataract surgical services are delivered, or improved technology. The demand for cataract surgery could be decreased through the implementation of effective primary prevention strategies, although successful strategies are currently unknown and/or untested. Given our current state of knowledge about cataract, it seems most feasible immediately to alter the health service delivery side of the equation to reduce the public health burden of cataract.