A global and regional analysis of Risk Factors for Blindness and Vision impairment in 2020 and their contribution to the change in prevalence of vision loss over 3 decades

Purpose : The Vision Loss Expert Group (VLEG) and Global Burden of Disease Study (GBD) collaboratively updated crude and age-standardised prevalence estimates of blindness and vision impairment and investigated inter-regional and age-specific changes over the 1990 to 2020 timeframe. Here we expand the focus to account for global and regional risk factors and address vision loss severities pertaining to all geographical locations. Methods : (1) Selection of 24 covariates with a potential link to vision-related disease from a database used across GBD modelling. (2) Analysis of the association of risk factors with crude and age-standardised prevalence estimates of blindness and vision impairment in 2020 separately for each severity: blindness, moderate and severe vision impairment, mild vision impairment, near vision impairment due to uncorrected presbyopia. (3) Analysis of the trend contribution of the percentage rates of change in risk factors to the rates of change in prevalence 1990-2020. Results : For adults (50+ yrs), for crude and age-standardised prevalence estimates for year 2020, we found a significant negative association of smoking prevalence, for all persons and for each sex. Maternal care and immunisation, sanitation proportion, health access & quality index and socio-demographic index were other significant age-standardised negative associations. Ophthalmologists/million population had a weak but significant protective effect, and we found positive associations for pollution (outdoor and indoor), stronger for greater vision impairment severities. Years in education per capita was weakly, negatively associated with vision loss prevalence yet zero education proportion has a stronger but positive association for both sexes. Multiple variable analysis led to generally lower effect sizes and reductions in significance of single variable findings. Conclusions : This study has confirmed associations at population level globally which appear to be stable over decades. In addition, the study has quantified the contribution of epidemiologically-based risk factors to vision loss at a macroregional level which is novel. This opens useful avenues for targeted intervention by policymakers. For example, reduction in sex inequity in blindness rates over 30 years has been positively associated with reducing overall blindness prevalence. This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually