Global estimates on the number of people blind or visually impaired by glaucoma: A meta-analysis from 2000 to 2020

Abstract Objectives: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by glaucoma and their proportion of the total number of vision-impaired individuals. Methods: A systematic review and meta-analysis of published population studies and grey literature from 2000 to 2020 was carried out to estimate global and regional trends. Moderate or severe vision loss (MSVI) was defined as a visual acuity of 6/60 or better but <6/18 (moderate vision loss) and visual acuity of 3/60 or better but <6/60 (severe vision loss). Blindness was defined as presenting visual acuity <3/60 or less than 10° visual field around central fixation. Results: Globally, in 2020, 3.61 million people were blind and nearly 4.14 million were visually impaired by glaucoma. Glaucoma accounted for 8.39% (95% uncertainty intervals [UIs]: 6.54, 10.29) of all blindness and 1.41% (95% UI: 1.10, 1.75) of all MSVI. Regionally, the highest proportion of glaucoma-related blindness was found in high-income countries (26.12% [95% UI: 20.72, 32.09]), while the region with highest age-standardized prevalence of glaucoma-related blindness and MSVI was Sub-Saharan Africa. Between 2000 and 2020, global age-standardized prevalence of glaucoma-related blindness among adults ≥50 years decreased by 26.06% among males (95% UI: 25.87, 26.24), and by 21.75% among females (95% UI: 21.54, 21.96), while MSVI due to glaucoma increased by 3.7% among males (95% UI: 3.42, 3.98), and by 7.3% in females (95% UI: 7.01, 7.59). Conclusions: Within the last two decades glaucoma has remained a major cause of blindness globally and regionally.