To assess the burden and temporal trends of blindness and vision loss attributable to type 2 diabetes mellitus (T2DM) in young adults aged 20–39y from 1990 to 2021.

Cross-sectional datasets were extracted from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021. Prevalence and years lived with disability (YLDs) metrics were applied to quantify temporal changes in blindness and vision loss across 1990–2021. Data were stratified by global, regional, and socio-demographic index (SDI) tiers, and further split by age and sex for comprehensive subgroup analysis. Joinpoint regression was adopted to detect inflection points of trend shifts. A Bayesian age-period-cohort model was utilized to forecast disease burden projections for 2045.

Globally, the prevalence of T2DM-related blindness and vision loss in young adults (20-39y) rose from 4.7 per 100000 population in 1990 to 6.4 per 100000 population in 2021 [average annual percentage change (AAPC)=1.03; P<0.001]. The YLD rate likewise increased from 0.5 per 100000 in 1990 to 0.7 per 100000 in 2021 (AAPC=1.02; P<0.001). Southeast Asia and Grenada bore the highest prevalence, whereas Central Latin America and Cambodia exhibited the highest YLD rates. Both prevalence and YLD rates increased markedly within the high-SDI quintile. Singapore was the only setting presenting declining prevalence and YLD trends. Females experienced steeper rises than males in prevalence (AAPC: 1.16 vs 0.88) and YLDs (AAPC: 1.16 vs 0.82).

The global disease burden of early-onset T2DM-induced visual impairment has increased substantially among 20–39-year-old individuals, particularly in high-SDI regions, with females facing a greater rising prevalence burden. Targeted intervention measures are warranted to guide integrated population-level prevention and clinical management frameworks.