Under-reporting difficulties in seeing among older people with clinically assessed vision impairment: an exploration of 12 surveys from sub-Saharan Africa

BACKGROUND: Individuals who do not perceive they have a health problem will not seek care, risking a deterioration of health status. We sought to understand how visually impaired individuals aged ≥50 y from 12 studies across sub-Saharan Africa self-reported their difficulties seeing, and to identify the factors associated with under-reporting. METHODS: We used R software to assess overall agreement between self-report and clinical assessment with a weighted kappa, and described the proportion of individuals accurately reporting, over-reporting and under-reporting their difficulties seeing. We used logistic regression to explore factors associated with under-reporting. RESULTS: In total, 5777/32 548 participants had moderate vision impairment (VI) or worse. Overall, agreement between clinically diagnosed VI and self-reported difficulties seeing was 0.41; 74.7% of participants self-reported a level of difficulty seeing that corresponded with their clinical VI but this varied significantly: individuals with no VI reported most accurately (83.8%), and blind individuals least accurately (18.7%). Individuals were less likely to under-report if they had other self-reported functional difficulties, 'other' primary causes of VI (compared with cataract), or were from certain locations. Individuals with unaddressed refractive error were more likely to under-report. CONCLUSIONS: Health planners need to design programmes to reach individuals who are less likely to perceive they have eye health problems. CONTEXTE: Les personnes qui ne se rendent pas compte qu'elles ont un problème de santé ne consultent pas, ce qui peut entraîner une détérioration de leur état de santé. Nous avons cherché à comprendre comment les personnes malvoyantes âgées de 50 ans et plus inclues dans 12 études menées en Afrique subsaharienne ont auto-déclaré leurs difficultés à voir, et à identifier les facteurs associés à la sous-déclaration.