Blindness and visual impairment among people with diabetes mellitus 40 years and older in the Limpopo Province, South Africa

Abstract

The aim of this study was to determine the prevalence and causes as well as the risk factors of visual impairment (VI) and blindness among Black South Africans with diabetes mellitus (DM) aged 40 years and older in Mopani District, Limpopo province, South Africa. This was a cross-sectional study in which Black South Africans with DM aged ≥40 years old were examined for VI and blindness. In addition, anthropometric as well as risk factors for VI and blindness were studied. A total of 225 participants were selected from seven Public Health Facilities in Mopani District. Data was collected using standard optometric instruments, anthropometric instruments and structured interviews. Data analysis was done using the Statistical Analysis System (SAS) and Microsoft Excel software packages. The ages of the participants ranged from 40 to 90 years with a mean of 61.5±10.49 years. There were more females (71.5%) than males (28.4%). The prevalence of uncorrected VI and blindness in the right eyes of the participants was 70.7% and 3.6%, respectively. In the left eyes, it was 72% and 3.1%, respectively. However, following optical correction, the prevalence in right eyes was 41.3% and 3.6%, respectively. In the left eyes, it was 42.2% and 3.1%, respectively. Risk factors that were individually associated with VI and blindness include age, educational qualification, monthly income, knowledge of DM types, oral DM treatment (pills), losing weight, compliance to losing weight, family history of DM, physical activity, and date of last eye examination .When logistic regression was used, knowledge of DM types, pills, and compliance to losing weight, family history of DM, monthly income and physical activity remained associated with VI and blindness. The high prevalence of VI in this diabetes population was not primarily due to DM itself, but due to refractive error and cataract, conditions which have effective and easy treatments. A total of 84% of the participants were visually impaired due to either refractive error or cataract or both and only 3.8% due to diabetes retinopathy. It is therefore recommended that appropriate and affordable refraction and cataract surgical services be made available and accessible to this population