Prevalence and pattern of refractive errors among Yanomami Indigenous people in the Brazilian Amazon: a cross-sectional observational study

Background: Refractive errors are the leading cause of preventable visual impairment worldwide, yet data from isolated Indigenous populations remain virtually absent from the global literature. The Yanomami, one of the largest Indigenous peoples in the Americas with recent and limited contact with non-Indigenous society, have no prior epidemiological data on refractive errors. Methods: A cross-sectional observational study was conducted in 2024 at the Yanomami Indigenous Health House, Boa Vista, Roraima, Brazil. A total of 158 self-identified Yanomami individuals aged 5 years or older were examined by an ophthalmologist. Refractive status was classified according to International Myopia Institute criteria. Results: Emmetropia was observed in 67.7% of participants, with a marked age-related decline from 100% in children aged 5 to 9 years to 38.6% in those aged 40 to 59 years. Myopia was present in 16.5% of participants, all low myopia; it was absent in children under 10 years and no high myopia was identified. Astigmatism affected 24.1% of participants and hyperopia 13.3%. Presbyopia was identified in 25.9%. Overall, 25.3% of participants presented with reduced visual acuity attributable to uncorrected refractive error, of whom 67.5% improved to normal or near-normal acuity (p < 0.001). Conclusions: This is the first characterisation of the Yanomami refractive profile, revealing a distinct myopia pattern shaped by high outdoor exposure and minimal near-work demands. Despite this, refractive correction remains effectively inaccessible to this population, leaving preventable visual impairment unaddressed and reflecting a profound health inequity. Corrective lens provision represents a high-impact, scalable intervention for this underserved community.