Rapid Assessment of Avoidable Blindness in Western Rwanda: Blindness in a Postconflict Setting

Abstract

BackgroundThe World Health Organization estimates that there were 37 million blind people in 2002 and that the prevalence of blindness was 9% among adults in Africa aged 50 years or older. Recent surveys indicate that this figure may be overestimated, while a survey from southern Sudan suggested that postconflict areas are particularly vulnerable to blindness. The aim of this study was to conduct a Rapid Assessment for Avoidable Blindness to estimate the magnitude and causes of visual impairment in people aged ≥ 50 y in the postconflict area of the Western Province of Rwanda, which includes one-quarter of the population of Rwanda.Methods and FindingsClusters of 50 people aged ≥ 50 y were selected through probability proportionate to size sampling. Households within clusters were selected through compact segment sampling. Visual acuity (VA) was measured with a tumbling “E” chart, and those with VA below 6/18 in either eye were examined by an ophthalmologist. The teams examined 2,206 people (response rate 98.0%). The unadjusted prevalence of bilateral blindness was 1.8% (95% confidence interval [CI] 1.2%–2.4%), 1.3% (0.8%–1.7%) for severe visual impairment, and 5.3% (4.2%–6.4%) for visual impairment. Most bilateral blindness (65%) was due to cataract. Overall, the vast majority of cases of blindness (80.0%), severe visual impairment (67.9%), and visual impairment (87.2%) were avoidable (i.e.. due to cataract, refractive error, aphakia, trachoma, or corneal scar). The cataract surgical coverage was moderate; 47% of people with bilateral cataract blindness (VA < 3/60) had undergone surgery. Of the 29 eyes that had undergone cataract surgery, nine (31%) had a best-corrected poor outcome (i.e., VA < 6/60). Extrapolating these estimates to Rwanda's Western Province, among the people aged 50 years or above 2,565 are expected to be blind, 1,824 to have severe visual impairment, and 8,055 to have visual impairment.ConclusionsThe prevalence of blindness and visual impairment in this postconflict area in the Western Province of Rwanda was far lower than expected. Most of the cases of blindness and visual impairment remain avoidable, however, suggesting that the implementation of an effective eye care service could reduce the prevalence further.

Cataract prevalence in Central-West region of São Paulo State, Brazil

“…Observing data from other Brazilian regions and developing countries, the prevalence of blindness from cataract in the general population is much higher than what was seen here, with 1.49% in the metropolitan region of São Paulo (10) , 2.11% in a Brazilian indigenous group from Amazonia (11) , 2.61% of the whole population in Cambodia (2) ; 4.26% in Nigeria (12) ; 1.17% of the over 50 population in Ruanda and Kenya (13) ; and 2.01% of over 50's in Paraguay (14) . Compared to other Latin American countries, our data is similar to the metropolitan area of Buenos Aires that has 0.5% of bilateral blindness caused by cataract (15) .…”

Ocular Findings in a Brazilian Rural Slave-Descendant Community: Eye Health in Quilombos

“…Considering studies published in the last 10 years, blindness prevalence in vulnerable groups vary from 1.1% in rural provinces from Burundi (Central Africa) to 8.1% in rural villages from Myanmar (South Asia). [12][13][14][15][16][17] Reasons for this wide variation may include sampling variations, age groups evaluated, availability of eye care services, genetic background of populations, and other specific environmental or regional causes.…”

“…[12][13][14][15][16][17] Interestingly, there is no common simple pattern to describe vision conditions found in these different populations. Visual impairment, for instance, may be among highest rates in the world -as in rural villages from Myanmar [12] or close to the lower rates from middleincome countries -as in Rwanda [13] and Burundi [16]. Therefore, minorities and unprivileged populations should not be considered a homogeneous group and the comprehensive evaluation of each case may be a key step toward fulfilling the goals of universal eye care.…”

The Need for a Revised Approach to Epidemiological Monitoring of the Prevalence of Visual Impairment

“…5,6,[8][9][10]14,15 In contrast, Powe and colleagues found that 89.7% of all eyes with cataract operated in the United States mostly during the 1980s-when conventional extracapsular surgery predominated-achieved visual acuity of 20/40 or better. 16 While developing country cases with advanced cataracts and possibly neglected co-morbidities likely are fundamentally more difficult and less likely to lead to good outcomes than US cases were in the 1980s, and the method of ascertaining visual outcome is non-identical, there appears to be a large quality gap.…”

“…At the most straightforward level, the results show us that blindness remains a major problem in Eritrea, and that diseases such as cataract and glaucoma which require ophthalmic care are an important cause of blindness, as in several other surveys from Africa and elsewhere in the world. [5][6][7][8][9][10][11][12][13][14][15] While more than half of severe visual loss or blindness was attributed to cataract, only about 1% was attributed to surgical complications. However, in reading further (as noted by the authors), we find that blindness due to complications of cataract surgery must be one of the leading causes of blindness in single eyes, because 182 eyes (39.2% of those operated) present with visual acuity worse than 6/60.…”