Prevalence and development of retinopathy in children and adolescents with type 1 (insulin-dependent) diabetes mellitus. A longitudinal study.

In 231 subjects with Type 1 diabetes mellitus aged 17.6 +/- 4.0 years, with a diabetes duration of 8.5 +/- 4.9 years at the end of the study, the prevalence and the development of retinopathy during a period of 5 years were studied. All patients were examined between one and six times both by ophthalmoscopy and fluorescein angiography. A total of 626 fluorescein angiographies were evaluated. By the end of the study, 109 out of 231 patients (47%) had developed retinal changes, half of which were classified as minimal (less than 5 microaneurysms). Thirty-eight patients (35% of those affected) had background (n = 28) or proliferative (n = 10) retinopathy. In subjects less than 15 years of age and diabetic for less than 5 years, retinal lesions were rare. With increasing age and duration of diabetes, both the prevalence and severity of retinal changes increased markedly. Life-table analysis was used to calculate the median individual risk for the development of early retinal changes, which was 9.1 years of diabetes duration. This risk differed in sub-groups with different ages at onset of diabetes, i.e. 12.1, 8.9 and 6.6 years (p less than 0.0001), with diabetes starting below 4, between 5 and 9, and after 10 years of age respectively. After 18 years of diabetes, every patient demonstrated at least incipient structural changes. Fluorescein angiography allowed the detection of retinopathy, on average, four years earlier than with ophthalmoscopy. The median interval between the 'onset' of retinopathy, as indicated by a few microaneurysms, and background retinopathy was 5 years.