The hidden burden of eye-care needs: how visual acuity definitions change estimates of need in 12 RAAB surveys across six countries
- 1Peek Vision, London, UK
Abstract
PurposeRapid Assessment of Avoidable Blindness (RAAB) surveys are widely used to estimate the prevalence and causes of blindness and vision impairment among adults aged 50 years and older. We examined how far estimates of eye-care need depend on whether presenting or pinhole acuity, and unilateral or bilateral impairment, is used.
MethodsWe analysed 12 RAAB surveys undertaken between 2018 and 2023 in India, Nepal, Pakistan, Kenya, Tanzania and Uganda. Three person-level measures were compared: presenting visual acuity (PVA) in at least one eye, PVA in the better-seeing eye, and pinhole acuity in the better-seeing eye. Estimates were adjusted for the two-stage cluster design and age-standardised to the WHO world standard population.
ResultsOf 48,185 participants examined (response rate 94.3%), vision impairment based on pinhole acuity in the better eye (9-19%) was substantially lower than on PVA in the better eye (18- 37%) or in at least one eye (33-51%). Increasing age (adjusted odds ratio [AOR] per year 1.106; 95% confidence interval [CI] 1.103-1.109), female sex (AOR 1.13; CI 1.08-1.19) and South Asian survey location (AOR 3.04; CI 2.78-3.33) were independently associated with impairment. Age-standardisation widened the difference between survey locations (prevalence ratio 1.50 crude, 1.66 standardised).
ConclusionsSubstantial vision impairment persists in the surveyed districts of both regions. The large gap between presenting and pinhole acuity indicates a considerable addressable burden, and restricting estimates to bilateral impairment in the better-seeing eye omits a further substantial share of need. The higher prevalence in the South Asian locations most plausibly reflects survey site selection and uncorrected refractive error rather than a regional epidemiological difference.
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BibTeX
@misc{bastawrous2026hidden,
title = {{The hidden burden of eye-care needs: how visual acuity definitions change estimates of need in 12 RAAB surveys across six countries}},
author = {A. Bastawrous and M. Katibeh and S. Latorre-Arteaga and M. Gichangi and A. Khan and S. Sabherwal and M. Kasadhakawo and S. Mishra and R. Oenga and F. G. Mndeme and A. Foster},
howpublished = {medRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.19.26363481},
url = {https://www.medrxiv.org/content/10.64898/2026.09.19.26363481v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - The hidden burden of eye-care needs: how visual acuity definitions change estimates of need in 12 RAAB surveys across six countries
AU - A. Bastawrous
AU - M. Katibeh
AU - S. Latorre-Arteaga
AU - M. Gichangi
AU - A. Khan
AU - S. Sabherwal
AU - M. Kasadhakawo
AU - S. Mishra
AU - R. Oenga
AU - F. G. Mndeme
AU - A. Foster
PY - 2026
DA - 2026/09/19
PB - medRxiv
DO - 10.64898/2026.09.19.26363481
UR - https://www.medrxiv.org/content/10.64898/2026.09.19.26363481v1
AB - PurposeRapid Assessment of Avoidable Blindness (RAAB) surveys are widely used to estimate the prevalence and causes of blindness and vision impairment among adults aged 50 years and older. We examined how far estimates of eye-care need depend on whether presenting or pinhole acuity, and unilateral or bilateral impairment, is used. MethodsWe analysed 12 RAAB surveys undertaken between 2018 and 2023 in India, Nepal, Pakistan, Kenya, Tanzania and Uganda. Three person-level measures were compared: presenting visual acuity (PVA) in at least one eye, PVA in the better-seeing eye, and pinhole acuity in the better-seeing eye. Estimates were adjusted for the two-stage cluster design and age-standardised to the WHO world standard population. ResultsOf 48,185 participants examined (response rate 94.3%), vision impairment based on pinhole acuity in the better eye (9-19%) was substantially lower than on PVA in the better eye (18- 37%) or in at least one eye (33-51%). Increasing age (adjusted odds ratio [AOR] per year 1.106; 95% confidence interval [CI] 1.103-1.109), female sex (AOR 1.13; CI 1.08-1.19) and South Asian survey location (AOR 3.04; CI 2.78-3.33) were independently associated with impairment. Age-standardisation widened the difference between survey locations (prevalence ratio 1.50 crude, 1.66 standardised). ConclusionsSubstantial vision impairment persists in the surveyed districts of both regions. The large gap between presenting and pinhole acuity indicates a considerable addressable burden, and restricting estimates to bilateral impairment in the better-seeing eye omits a further substantial share of need. The higher prevalence in the South Asian locations most plausibly reflects survey site selection and uncorrected refractive error rather than a regional epidemiological difference.
ER -