High prevalence in Malawi of sight-threatening retinopathy and visual impairment caused by diabetes: identification of population-specific targets for intervention.

AIMS: To report the prevalence of all grades of diabetic retinopathy and associations with demographic, clinical and biochemical variables in people with diabetes in Southern Malawi. METHODS: We report baseline data from a 24-month prospective cohort study. Subjects were systematically sampled from two hospital-based, primary care diabetes clinics. Visual acuity, glycaemic control, systolic blood pressure, HIV status, urine albumin-creatinine ratio, and haemoglobin and serum lipid levels were assessed. Retinopathy was graded at an accredited reading centre using modified Wisconsin grading of four-field mydriatic photographs. RESULTS: A total of 357 subjects were studied. Of these, 13.4% subjects were HIV-positive and 15.1% had anaemia. The overall prevalence rates of any retinopathy, sight-threatening diabetic retinopathy and proliferative retinopathy were 50.1% (95% CI 44.9-55.3), 29.4% (95% CI 24.7-34.1) and 7.3% (95% CI 4.6-10.0), respectively. In multivariate logistic analysis the presence of sight-threatening retinopathy was associated with duration of diabetes (odds ratio 1.11, 95% CI 1.05-1.17), HbA1c (odds ratio 1.31, 95% CI 1.13-1.50), systolic blood pressure (odds ratio 1.03, 95% CI 1.01-1.04), haemoglobin (odds ratio 0.98, 95% CI 0.96-0.99) and LDL cholesterol (odds ratio 1.63, 95% CI 1.18-2.25). No significant association with HIV status was observed. In all, 3.6 and 1.4% of people in our study cohort had visual acuity worse than 6/18 and 6/60 in the better eye, respectively. CONCLUSIONS: The present study found a prevalence of sight-threatening retinopathy in diabetes clinics in one Sub-Saharan African country of approximately four times that reported in recent European studies and a prevalence of proliferative retinopathy approximately 10 times higher. The association of sight-threatening retinopathy with lower haemoglobin level is a new finding. Our results highlight the urgent need for provision of services for retinopathy detection and management to avoid a large burden of vision loss.

Epidemiology of diabetic retinopathy and maculopathy in Africa: a systematic review.

AIM: To summarize findings from studies reporting the prevalence and incidence of diabetic retinopathy and diabetic maculopathy in African countries in light of the rising prevalence of diabetes mellitus. METHODS: Using a predefined search strategy, we systematically searched MEDLINE, EMBASE, Science Citation index and Conference Proceedings Citation index, African Index Medicus and the grey literature database 'OpenSIGLE' for studies published between January 1990 and February 2011. Included studies reported prevalence or incidence of diabetic retinopathy or diabetic maculopathy of subjects with diabetes resident in African countries. RESULTS: Sixty-two studies from 21 countries were included: three population-based surveys; two cohort studies; five case-control studies; 32 diabetes clinic-based, nine eye clinic-based and 11 other hospital-based surveys. Included studies varied considerably in terms of patient selection, method of assessing the eye and retinopathy classification. In population-based studies, the reported prevalence range in patients with diabetes for diabetic retinopathy was 30.2 to 31.6%, proliferative diabetic retinopathy 0.9 to 1.3%, and any maculopathy 1.2 to 4.5%. In diabetes clinic-based surveys, the reported prevalence range for diabetic retinopathy was 7.0 to 62.4%, proliferative diabetic retinopathy 0 to 6.9%, and any maculopathy 1.2 to 31.1%. No obvious association between prevalence and income level of the country was detected. CONCLUSIONS: Large, community-based cross-sectional and cohort studies are needed to investigate rates and determinants of prevalence of diabetic retinopathy, incidence and progression in Africa. Consensus is needed on the most appropriate methods of identification and classification of retinopathy for research and clinical practice. Estimates of prevalence of diabetic retinopathy, proliferative diabetic retinopathy and maculopathy are comparable with recent European and American studies.

Management of diabetic retinopathy.

Sub-Saharan Africa faces an epidemic of diabetes. Visual loss from diabetic retinopathy (DR) is both preventable and treatable. This article reviews the epidemiology and clinical features of DR and current evidence-based interventions in three areas: primary prevention of retinopathy by optimum medical management, early detection of pre-symptomatic disease and management of established retinopathy to prevent or mitigate visual loss. There are significant challenges to DR care in resource poor environments. Appropriate provision of effective interventions by health services can reduce social and economic costs associated with patient care.

Teaching corner: Regional anaesthesia for ophthalmic surgery.

Performing safe and effective regional anaesthesia for ophthalmic surgery is an important skill for anaesthetic and ophthalmologic practitioners. Akinetic sharp-needle blocks are generally safe but rare, sight and life threatening complications occur. Sub-Tenon's block using a blunt canula provides akinesa and is a safer alternative but serious complications have been reported. This review provides an introduction to the relevant anatomy, local anaesthetic drugs and commonly used techniques and a practical guide to their safe performance.

Teaching Corner: Regional Anaesthesia for Ophthalmic Surgery

Performing safe and effective regional anaesthesia for ophthalmic surgery is an important skill for anaesthetic and ophthalmologic practitioners. Akinetic sharp-needle blocks are generally safe but rare; sight and life threatening complications occur. Sub-Tenon's block using a blunt canula provides akinesa and is a safer alternative but serious complications have been reported. This review provides an introduction to the relevant anatomy; local anaesthetic drugs and commonly used techniques and a practical guide to their safe performance