Visual impairment and blindness in the Xingu Indigenous Park – Brazil

Abstract

Background Most estimates of visual impairment and blindness worldwide do not include data from specific minority groups as indigenous populations. We aimed to evaluate frequencies and causes of visual impairment and blindness in a large population sample from the Xingu Indigenous Park. Methods Cross-sectional study performed at Xingu Indigenous Park, Brazil, from 2016 to 2017. Residents from 16 selected villages were invited to participate and underwent a detailed ocular examination, including uncorrected (UVA) and best-corrected visual acuity (BCVA). The main cause of UVA < 20/32 per eye was determined. Results A total of 2,099 individuals were evaluated. Overall, the frequency of visual impairment and blindness was 10.00% (95% CI: 8.72–11.29%) when considering UVA, decreasing to 7.15% (95% CI: 6.04–8.25%) when considering BCVA. For each increasing year on age, the risk of being in the visually impaired or blind category increased by 9% (p < 0.001). Cataracts (39.1%) and uncorrected refractive errors (29.1%) were the most frequent causes of visual impairment and blindness in this population. The main causes among those aged 45 years and more were cataracts (54.5%) while refractive errors were the main cause in adults aged 18 to 45 years (50.0%) and children up to 18 years old (37.1%). Conclusions A higher frequency of visual impairment and blindness was observed in the indigenous population when compared to worldwide estimates with most of the causes being preventable and/or treatable. Blindness prevention programs should focus on accessibility to eye exam, cataract surgeries and eyeglass distribution.

Prevalence and Pattern of Visual Impairment among Adult Population in Mangu Local Government Area of Plateau State, Nigeria

“…The leading causes of preventable visual impairment in the studied area were cataracts (10.2%), refractive errors (8.4%), glaucoma (7.0%), age-related macular degeneration (4.1%), and diabetic retinopathy (2.1%). This is in consonance with the study carried out by Hudu et al in Jos North Local Government Area of Plateau State, Nigeria, [37], Nigeria Army Eye Centre, Bonny Cantonment Lagos, Nigeria, [38] as well as in other countries [39][40][41][42].…”

Indigenous Eye Health in the Americas: The Burden of Vision Impairment and Ocular Diseases

“…Tropical Latin America is one of the sub-regions with the highest estimated rates of MSVI (10.60%) and blindness (2.71%) in older adults in the Americas [1]. A recent study performed with residents from the Xingu Indigenous Park in Brazil following the same GDB criteria of classification has shown frequencies of MSVI and blindness substantially higher than those calculated for the general population, reaching 22.58% and 5.92%, respectively, in adults 45 years and older [19].…”

“…The cataract rates in older adults, regardless of vision acuity status, have varied from 12.2% in Northwestern and Alaskan Natives in the USA [28] to 54.5% in groups from the Xingu Indigenous Park in Brazil [19]. These values are sensitive to the population's access to cataract surgeries, which may explain the high frequency of disease in Indigenous populations with limited access to specialized eye health services.…”

“…More than achieving universal health coverage in a country, equity should be prioritized, otherwise, socially advantaged groups will be more likely to use the new or improved services [71,72]. Specific actions include the following: (1) access: increasing the number of clinic sites, rural locations, and eye care sessions, not only with ophthalmologists, but also with other eye health practitioners as optometrists, ophthalmic technologists, and/or trained nurses should improve the number of patient seen, dispensing spectacles, and surgery referrals [72,73]; (2) integration with family medicine/primary care: several communities have general health programs with systemic condition screening and could include ocular health screening tools into their practice to detect and timely refer cases of vision impairment and blindness for specialized care [19,72,74]; (3) telemedicine: several telemedicine protocols in ophthalmology focused on diabetes retinopathy, glaucoma, and cataract have been shown to be effective in populations living in remote areas and should be used as models towards Indigenous population groups [75][76][77]; (4) customized propaedeutics: specific techniques should be indicated to populations living in remote areas, for example, manual small incision cataract surgery (MSICS) techniques in resource-constrained health care settings such as Indigenous communities [78]; (5) education on eye health: by promoting basic knowledge on eye health, the population can better understand the importance of seeking timely treatment, improving visual outcomes [79,80]; (6) quality data: more studies focused on Indigenous population's eye health should be performed with appropriate methodology and collection of key indicators such as eCSC and eREC, and studies performed in the general population should collect data on the participants' ethnicity/race [52,53].…”

“…Despite the differences in the vision impairment and blindness definitions, it is a clear significant difference in the frequencies between high-income North America and tropical Latin American countries. When considering adults over 40 years old and the BCVA method, the highest frequencies of vision impairment and blindness in high-income North America sum 11.1% [27] while in the tropical Latin America it can reach 28.5% [19].…”