Prevalence of blindness and visual impairment in a population of people with diabetes

Purpose To assess the prevalence of visual impairment and the underlying causes in a population of people with diabetes. Method A population-based study of a defined population of people with diabetes in a district in the North West of England was done. There were 7652 known people with diabetes, representing 2.12% of target general population of 361 050. The main outcome measures were the prevalence of blindness and significant visual impairment (less than 6/18 corrected vision in their better eye) and the underlying causes. Results Visual acuity data on 6482 (84.7%) of the 7652 individuals were obtained. Of these, 184 had significant visual impairment (prevalence 2.84%) including 49 who were blind (vision of less than 3/60 in their better eye, prevalence 0.75%); if blindness was defined as vision less than or equal to 6/60, prevalence was 1.13% (n = 73). Details of 3 individuals could not be ascertained. Only 67 were registered, either as partially sighted (n = 42) or as blind (n = 25). In the majority (n = 133; 68%) of these 181 individuals the visual impairment was due to causes other than diabetic retinopathy. Conclusions The prevalence of blindness and visual impairment in our population of people with diabetes was low. Non-diabetic eye disease accounted for the majority of this visual impairment. This provides essential baseline data against which future progress can be assessed. Screening and treatment can greatly reduce the incidence of visual impairment due to diabetic retinopathy, but its impact on overall visual impairment rates in the population of people with diabetes will be more modest.