Diabetic retinopathy and visual impairment in a Norwegian diabetic coast population with a high dietary intake of fish oils. An observational study.

PURPOSE: To present retinal and visual findings in a Norwegian west coast diabetic population and to elucidate the effect of dietary intake of marine polyunsaturated fatty acids (PUFAs) on the development of diabetic retinopathy (DR). METHODS: In an eye practice in an archipelago of 314 km², serving a population of about 40 000, we recorded the prevalence of visual impairment and DR in a referred diabetic population. 510 consecutive patients were included, 238 females and 272 males. 50 patients had type I and 460 had type II diabetes mellitus (DM). Self-reported medication, diet supplements, HbA1c and fish consumption were registered. RESULTS: In the type I group, the median age was 44.5 and median DM duration 11.5 years [1-44]. 48% had photographic evidence of DR, 8 patients (16%) had proliferative retinopathy (PDR), and 6 patients (12%) had diabetic macular oedema (DME). All had best-corrected visual acuity (BCVA) of 0.5 (log MAR 0.3) or better in the best eye. In the type II group, the median DM duration was 8 years [1-53], and median age was 66. 98% had best eye BCVA at or better than 0.5 (log MAR 0.3) in the best eye. CONCLUSION: None of the 510 patients had BCVA worse than 0.3 (log MAR 0.48) due to diabetic retinopathy. Compared to similar studies, we found a very low visual impairment rate. A possible protective effect of PUFA on the prevalence and progression of diabetic microangiopathy including retinopathy is discussed.

Prevalence of diabetic retinopathy in Norway: report from a screening study.

PURPOSE: The purpose of the present study was to investigate the prevalence of diabetic retinopathy (DR) in Norway and adherence to the Norwegian Guidelines for screening for diabetic eye disease. METHODS: Two hundred and ninety-nine people with diabetes were randomly recruited from the patient lists of randomly selected general practitioners from three different regions in Norway. Retinopathy was evaluated from retinal photographs after dilation of the pupils using a red-free digital camera and visual acuity was measured using the Snellen chart. The patients were interviewed about their ophthalmological and general diabetes control, duration and type of diabetes and medical treatment. RESULTS: The prevalence of any DR was 28%, 66% for type 1 and 24% for type 2 diabetes. The prevalence of proliferative retinopathy was 38% in type 1 and 1.5% in type 2 diabetes. Two patients (one type 1 and one insulin-treated type 2) were visually impaired (visual acuity 0.3 or worse in the better eye) because of proliferative DR. Twenty-six per cent of the patients had never been to an eye examination, and only 69% attended routine eye examinations. Patients who did not attend regular eye screenings were mostly people with type 2 diabetes. CONCLUSION: The prevalence of DR was higher than previously reported in Norway. Screening for DR did not follow guidelines in a considerable proportion of the patients with type 2 diabetes. There is place for improvement in the implementation of guidelines for screening for DR for people with type 2 diabetes in Norway.