Cataract-related blindness and vision impairment in 2020 and trends over time in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study.

Abstract

Purpose : To contribute to the WHO initiative, VISION 2020: The Right to Sight, we report extensively updated estimates of global vision loss burden due to cataract presenting estimates for 2020, including changes over time.

Methods : Population-based surveys of eye disease from January, 1980, to October, 2018 were collated by the Vision Loss Expert Group of the Global Burden of Disease Study in the Global Vision Database. We fitted hierarchical models to estimate age-standardised prevalence (with 95% uncertainty intervals [UIs]) of moderate and severe vision impairment (MSVI; presenting visual acuity from <6/18 (20/60) to 3/60 (10/200)) and blindness (<3/60 (10/200) and/or less than 10° visual field around central fixation) caused by cataract by age, global region, and year. Data sparsity at younger ages required the analysis focused on adults aged ≥50 years.

Results : In 2020, worldwide an estimated 15.2 million (12.7-17.9) people aged 50+ years were blind, and a further 78.8 million (67.2-91.4) had MSVI, due to cataract. There had been an increase of 29.7% in cases of cataract blindness and 93.1% in cases of MSVI since 2000. Over the same period, age-standardised prevalence of cataract blindness decreased by 27.5% and MSVI increased by 7.2%. Between 2000 and 2020, the age-standardised prevalence of cataract blindness in males decreased to a greater extent than in females (-31.8% vs -24.8%); similarly the increase in cataract MSVI was less for males (+4.7%) than females (+8.9%). Among GBD super-regions, South Asia had the highest cataract blindness and MSVI burden in 2020 (blind: 2.23%; 1.89-2.61, MSVI: 9.46%; 8.11-10.93). The most profound reductions in cataract blindness rates between 2000 and 2020 occurred in Southeast Asia, East Asia and Oceania (-43.0%), North Africa and Middle East (-40.0%), and South Asia (-36.5%).

Conclusions : The World Health Assembly Global Action Plan target of a 25% reduction from 2010 to 2019 in avoidable vision impairment (WHA 66.3 24/5/2013) was met for cataract blindness but not for MSVI. However, decreases in prevalence were more than offset by global population growth and aging, leaving more people cataract blind and visually impaired than ever before. Globally, immense increases in resource mobilization for treating cataract are required.

This is a 2021 ARVO Annual Meeting abstract.