Forecasting regional disparities in cataract surgery demand and ophthalmologist supply in Japan: a prefecture-level forecasting study

Objective Cataracts are the leading cause of poor vision in Japanese adults. As Japan’s population is rapidly ageing, the demand for cataract surgery will continue to increase. Despite this, quantitative research evaluating both supply and demand of cataract surgery is lacking. The objective of this study was to forecast future cataract surgery demand and the supply of ophthalmologists in Japan by region and evaluate the cataract surgery demand-supply balance considering regional differences in demographics and medical resources. Methods and analysis Based on the Ministry of Health, Labour and Welfare’s ‘NDB Open Data’, age-specific and sex-specific cataract surgery rates were calculated from the number of billed procedures. These rates were applied to the Ministry of Internal Affairs and Communications’ ‘Population Estimates’ and National Institute of Population and Social Security Research’s ‘Future Population Projections’ to estimate demand for 2030, 2040 and 2050. Future supply of ophthalmologists was estimated using linear regression based on data from the ‘Survey of Physicians, Dentists, and Pharmacists’. The demand-supply ratio (demand divided by supply) was calculated for each prefecture. The demand-supply ratio multiplier for each year was calculated using 2022 as the base year. Results The estimated number of cataract surgeries was 1 929 848 in 2030, 2 373 260 in 2040 and 2 863 733 in 2050, with a significant increase projected for individuals in their 70s and aged 80+. Although most prefectures were expected to see a gradual increase in ophthalmologist numbers, a decrease was projected for some regional areas. Consequently, the demand-supply ratio was projected to increase nationwide, with a larger increase in regional areas, suggesting a widening disparity between regional and metropolitan areas. Conclusion Demand for cataract surgery would continue to rise, potentially increasing demand-supply imbalances, particularly in regions with ageing populations. Re-examination of the regional allocation of medical resources is necessary to correct disparities in access to treatment. These projections are subject to limitations related to the use of publicly available data and assumptions based on past trends, which may not fully reflect regional practice variation or future changes in surgical capacity.