Rapid assessment of avoidable blindness in Uruguay: results of a nationwide survey

To investigate and describe the prevalence and causes of blindness and moderate and severe visual impairment in older adults living in Uruguay.

All individuals aged ≥ 50 years old living in randomly selected clusters were eligible to participate. In each census enumeration unit selected, 50 residents aged 50 years and older were chosen to participate in the study using compact segment sampling. The study participants underwent visual acuity (VA) measurement and lens examination; those with presenting VA (PVA) < 20/60 also underwent direct ophthalmoscopy. Moderate visual impairment (MVI) was defined as PVA < 20/60-20/200, severe visual impairment (SVI) was defined as PVA < 20/200-20/400, and blindness was defined as PVA < 20/400, all based on vision in the better eye with available correction.

Out of 3 956 eligible individuals, 3 729 (94.3%) were examined. The age- and sex-adjusted prevalence of blindness was 0.9% (95% confidence interval (CI): 0.5-1.3). Cataract (48.6%) and glaucoma (14.3%) were the main causes of blindness. Prevalence of SVI and MVI was 0.9% (95% CI: 0.5-1.3) and 7.9% (95% CI: 6.0-9.7) respectively. Cataract was the main cause of SVI (65.7%), followed by uncorrected refractive error (14.3%), which was the main cause of MVI (55.2%). Cataract surgical coverage was 76.8% (calculated by eye) and 91.3% (calculated by individual). Of all eyes operated for cataract, 70.0% could see ≥ 20/60 and 15.3% could not see 20/200 post-surgery.

Prevalence of blindness in Uruguay is low compared to other Latin American countries, but further reduction is feasible. Due to Uruguay's high cataract surgical coverage and growing proportion of people ≥ 50 years old, the impact of posterior pole diseases as a contributing factor to blindness might increase in future.