Global, regional, and national burden of glaucoma, 1990–2021: trends, future projections to 2050, and high fasting plasma glucose attribution

Background: Glaucoma remains the leading cause of irreversible blindness. While age-standardized rates are declining, population aging and growth continue to expand absolute numbers. The contribution of modifiable metabolic risk—especially elevated fasting plasma glucose (FPG)—to regional and temporal patterns has not been systematically quantified. The aim of this study is to describe global, regional, and national glaucoma burden from 1990 to 2021, analyze temporal trends, project future trajectories to 2050, and assess the population-attributable fraction of high FPG.

Methods: We used Global Burden of Disease Study 2021 data, analyzing prevalence, age-standardized prevalence rate (ASPR), disability-adjusted life-years (DALYs), and age-standardized DALY rate (ASDR), stratified by sex, age, region, and Socio-demographic Index (SDI). Temporal change was quantified with estimated annual percentage change (EAPC), and projections to 2050 were made using ARIMA models.

Results: Global cases rose from 40.72 million in 1990 to 75.88 million in 2021, while ASPR declined from 116.29 to 90.12 per 100,000 (EAPC = −0.82). DALYs increased from 46.76 million to 75.99 million, whereas ASDR declined from 13.37 to 9.05 per 100,000 (EAPC = −1.25). Adults aged 70–79 years and males consistently showed the greatest burden. Low-SDI regions had the highest age-standardized burden, whereas high-SDI regions had the lowest. Projections indicate continued reductions in ASPR and ASDR through 2050, but absolute numbers will continue to rise. High FPG accounted for 7.9% of glaucoma DALYs in 1990 and increased to 12.8% in 2021; the relative increase was steepest in middle- and low-middle-SDI settings.

Conclusions: Declining age-standardized rates mask a growing total glaucoma burden driven by demographic change. The rising metabolic contribution highlights the need for integrated eye-care and systemic health strategies, particularly in resource-limited contexts.