Older adults, diabetes mellitus and visual acuity: a community-based case-control study

Main objectives: to screen for impaired distance visual acuity in older adu lts living at home, both with and without diabetes mellitus to determine wh ether diabetes increases the likelihood of visual impairment and to identif y associated factors. Design: case-control study. Settings: three districts of Wales: North Clwyd, Powys and South Glamorgan, with assessments in subjects' homes. Subjects: 385 with diabetes mellitus and 385 age- and sex-matched controls. Main outcome measures: visual acuity measures, short form (SF)-36 quality o f life scores Results: we observed impairment of visual acuity in 40% of those with diabe tes mellitus and 31% of controls. Diabetes was associated with an increased risk of visual impairment [odds ratio 1.50 (95% confidence interval 1.09-2 .05), P = 0.013]. The pinhole test identified uncorrected refractive error in 11% of the 63 patients with diabetes and 12% of the 49 controls who wore glasses, and in 51% of the 91 patients and 84% of the 69 controls who did not wear glasses (P < 0.001). Increasing age (P < 0.001) and female sex (P = 0.014) were significantly associated with visual impairment in both group s, whilst history of foot ulceration (P = 0.001), duration of diabetes (P = 0.018) and treatment with insulin (P < 0.001) were significantly associate d with visual impairment in subjects with diabetes. We observed a significa nt association between impaired visual acuity and five domains of the SF-36 (physical and social functioning, mental health, vitality, and health perc eptions; P < 0.01 in each case). Conclusion: older adults living at home have a high prevalence of uncorrect ed visual impairment. Diabetes mellitus is associated with significantly in creased risk of visual loss. This impairment is associated with detriments in health-related quality of life. We recommend earlier use of optometry se rvices and assessment of visual acuity by clinicians.