Global trends in blindness and moderate to severe visual impairment due to trachomatous corneal opacity 1984-2020

Abstract

Purpose : Trachomatous corneal opacities (CO) can lead to blindness, yet the global prevalence and regional differences are unclear. We provide global estimates of the prevalence of trachomatous corneal blindness and moderate to severe visual impairment (MSVI) and examine the burden by age, gender, and geographic region from 1984-2020.

Methods : Data were obtained from The Global Burden of Disease Vision Loss Expert Group (VLEG) and a search of published literature. Time trends globally and regionally were evaluated using a univariable Poisson log-linear model with a generalized estimating equation (GEE) method. Poisson log-linear models with GEE were used to determine differences in prevalence by region, age group, and sex. Age-standardized estimates of global prevalence of blindness and MSVI were calculated using the 2015 United Nations standard population.

Results : The global prevalence of blindness due to trachomatous CO in those 50 years and older was 0.013% (95% CI=0.006% to 0.043%); MSVI was 0.180% (95% CI=0.006% to 0.049%). Trachomatous CO blindness and MSVI was higher in older age groups, females, and was significantly higher in the African regions compared to other regions. A global decrease in blindness rates over time was found (prevalence rate ratio estimate=0.91, 95% confidence interval=0.86 to 0.96). However, the decline in MSVI rates was only observed in Asian countries, with no change in rates of MSVI over time in the African/Middle Eastern countries.

Conclusions : Females are more likely than males to be blind or have MSVI from trachomatous CO. Overall, the rates are declining worldwide, but the decline in MSVI is driven by the decline in Asian countries, which likely reflects improvements in socioeconomic development over time.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.