Formal registration of visual impairment in people with diabetic retinopathy significantly underestimates the scale of the problem: a retrospective cohort study at a tertiary care eye hospital service in the UK.

AIMS: To analyse the prevalence of visual impairment (VI), compare it to certification of visual impairment (CVI) and analyse VI associations in patients with diabetic retinopathy (DR). METHODS: Retrospective cohort study, which included 8007 patients with DR referred from the English diabetic eye screening programme to a tertiary referral eye hospital. Main outcome measure was VI, defined as vision in the best eye of <6/24. We conducted a multivariable logistic regression for VI as primary outcome of interest, controlling for age, sex, type of diabetes, baseline DR grade, ethnicity and index of multiple deprivation (IMD). RESULTS: Mean age was 64.5 (SD 13.6) years; 61% of patients were men; and 31% of South Asian ethnicity. There were 68 patients with CVI during the study period, and 84% (272/325) of patients with VI did not have CVI after a mean follow-up of 1.87 (SD ±0.86) years. Older age showed a positive association with VI (OR per decade rise 1.88, 95% CI 1.70 to 2.08; p=1.8×10-34). Men had a lower risk of VI (OR 0.62, 95% CI 0.50 to 0.79, p=6.0×10-5), and less deprivation had a graded inverse association with VI (OR per IMD category increase 0.83, 95% CI 0.74 to 0.93, p value for linear trend 0.002). CONCLUSION: The majority of people with vision impairment are not registered at the point of care, which could translate to underestimation of diabetes-related VI and all-cause VI at a national level if replicated at other centres. Further work is needed to explore rates of VI and uptake of registration.

Comparing diabetic retinopathy lesions in scanning laser ophthalmoscopy and colour fundus photography.

PURPOSE: To evaluate the detection of different lesions of diabetic retinopathy (DR) in scanning laser ophthalmoscopy (SLO) compared to colour fundus photographs within the same retinal field. METHODS: Scanning laser ophthalmoscopy and colour fundus photographs of 67 eyes taken on the same day of dilated patients with different grades of diabetic retinopathy were retrospectively examined. SLO images were then cropped to match the size and position of its 45-degree colour fundus photograph equivalent. Five independent masked graders assessed the images. Features of DR including haemorrhages, microaneurysms, exudates, cotton wool spots, intraretinal microvascular abnormalities, venous beading and neovascularization were analysed. Additionally, each image was classified according to Early Treatment of Diabetic Retinopathy Study (ETDRS) grading and English Diabetic Eye Screening Programme (DESP) grading. RESULTS: There was moderate to good agreement in ETDRS and DESP grading between SLO and colour fundus photographs within individual graders (weighted kappa range 0.45-0.65). The average number of microaneurysms for SLO and colour photographs showed a high degree of agreement (ICC: 0.92). Equally, the average number of blot haemorrhages in SLO and colour images showed strong agreement (ICC: 0.98) and the average number of cotton wool spots in SLO and colour images correlated well (ICC: 0.92). For these three lesions, the intergrader reliability was good (ICC ≥0.66) for both modalities. CONCLUSION: There was good correlation in detected microaneurysms, blot haemorrhages and cotton wool spots between SLO and colour fundus photographs. However, there was intergrader variability in flame haemorrhage, intraretinal microvascular abnormalities, venous beading and neovascularization grading with both modalities.