The regional distribution of diabetic retinopathy lesions may reflect risk factors for progression of the disease

Background. Diabetic retinopathy is graded by sen-ii-quantitative assessment of the morphological lesions as seen on fundus photographs. This grading method mainly considers the type and number of retinopathy lesions, implying that the diagnostic value of the regional distribution of retinopathy lesions is largely unknown. Design and methods: Case control design. The study group consisted of fifteen diabetic patients successively examined in a screening clinic, with retinopathy lesions predominantly around the larger vascular arcades. The control group consisted of fifteen patients pairwise matched with the patients in the study group regarding sex, age, diabetes type, and diabetes duration. The two groups were compared with respect to the distribution of individual retinal lesions (microaneurysms/dot haemorrhages, blot haemorrhages, cotton wool spots, and hard exudates) around the larger vascular arcades and in the macular area, hypertensive vascular abnormalities (crossing phenomena, arteriolar narrowing, arteriolar fight reflex), metabolic regulation, and blood pressure. Results: The patients in the study group had significantly more microaneurysms and haemorrhages around the larger vascular arcades than had the control group, but there was no difference between the vascular changes in the two groups. The study group had significantly higher blood pressure than had the control group, whereas there was no significant difference in metabolic regulation between the two groups. Conclusions: The findings suggest the existence of a hypertensive-like retinopathy in diabetic patients with lesions mainly around the larger vascular arcades, but with no increase in hypertensive vascular changes. This pattern is not identified with current semi-quantitative grading methods. Further improvement of clinical decisions made from fundus photographs of diabetic retinopathy requires the development of computerised methods for quantitative assessment of retinal lesions.