Correctable visual impairment among people with diabetes in Hong Kong

AbstractBackground: The prevalence of visual impairment is known to be higher in a diabetic population than in a non‐diabetic population. How much of this visual impairment may be attributed to uncorrected refractive error is unclear. This study examined the prevalence of visual impairment in a Hong Kong diabetic population to determine the proportion of the visual impairment that could be corrected with prescription spectacles.Methods: Patients with type 2 diabetes mellitus (T2DM) were recruited as subjects for this study. All subjects underwent a standardised diabetic retinopathy screening that included measurement of presenting distant vision, biomicroscopic examination of the anterior eye and a retinal examination. For those subjects whose visual acuity was worse than 6/9.5, autorefraction was performed. In this study, we classified visual impairment into three categories: no visual impairment (visual acuity in the better eye better than or equal to 6/18), mild visual impairment (visual acuity in the better eye between 6/18 and 6/60) and severe visual impairment (visual acuity in the better eye less than or equal to 6/60).Results: For the 2,301 subjects who participated in this study, the mean age at examination was 61.4 ± 10.5-years (range, 23 to 92-years). Regarding visual acuity, 11.3 per cent (259/2,301) of subjects had visual impairment with 10.6 per cent being mild (244/2,301) and 0.7 per cent severe (15/2,301). After correction with a prescription determined by autorefraction, the prevalence of visual impairment dropped to 4.0 per cent (91/2,301). Nearly 70 per cent (168/259) of visual impairment was correctable by prescription spectacles and 21.6 per cent (56/259) of subjects were likely to benefit from cataract surgery.Conclusion: For our sample of diabetic patients, nearly 70 per cent of the visual impairment could be remedied by a spectacle correction. In the care of the diabetic eye, eye‐care providers should not focus solely on diabetic retinopathy. The quality of life in people with T2DM can be improved simply by eliminating uncorrected refractive errors.Key words: cataractdiabetic mellitusHong Kongrefractive errorsvisual impairment ACKNOWLEDGEMENTSWe thank the team at the Lai King Integrative Community Health Center for assistance in the collection of the data in this study. We also thank Professor Peter Swann and the anonymous reviewers for helpful advice on this manuscript. The research was supported by grants from The Hong Kong Polytechnic University (1‐BBZD, J‐BB7P). The research data reported in this manuscript were presented in the conference of American Academy of Optometry in 2008.