Predicting diabetic retinopathy

The purpose of this study was to determine the occurrence and severity of diabetic retinopathy and to clarify its association with the duration of diabetes and several other factors in an outpatient diabetic population. The material consisted of 328 diabetics, mainly (77%) C-peptide negative, type 1 diabetics. The mean age of the patients was 45 years, and the mean duration of diabetes was 15 years. Retinal changes were assessed by ophthalmoscopy and widefield fundus photography. All retinopathy was confirmed in 59% and proliferative retinopathy (PR) in 20% of the patients. The frequency of diabetic retinopathy was 15% in patients with diabetes for less than five years but 100% in those with diabetes for 30 or more years. In type 1 diabetics PR was seen only after 10 or more years' duration but, after 20 years' duration it was seen in half of the patients with type 1 and in one-third of the patients with type 2 diabetes. The patients with diabetic nephropathy often had PR. In type 1 diabetics with onset of the disease less than 30 years peripheral sensory neuropathy, coronary disease, hypertension and leg-vessel disease were also often associated with PR. Because one reason for visual handicapping in diabetes is the delay of the diagnosing of vision-threatening lesions screening for treatable retinopathy should be intensive after 10 years' duration and in poorly-controlled diabetics even earlier.