Retinopathy in adolescents and young adults with onset of insulin-dependent diabetes in childhood.

Retinal studies were done in 181 postpubescent, insulin-dependent diabetic patients who developed diabetes before the age of 20. Retinal studies included serial direct ophthalmoscopic examinations, stereoscopic fundus photography and fluorescein angiography. At the time of retinal studies, muscle biopsies also were done to measure capillary basement membrane thickness (CBMT) as an index of early microvascular changes in skeletal muscles. Assessment of clinical metabolic control, interpretation of retinal findings, and CBMT were done independently. No retinopathy was detected in patients observed continuously and known to have been in higher degrees of metabolic control. Twenty-five patients in lower degrees of control for extended periods had retinopathy. CBMT was found to be labile and to progress or regress within a year depending on the degree of control. All patients in lower degrees of control with retinopathy had increased CBMT, but if they subsequently attained and maintained a high degree of control for a year, then CBMT diminished and there was no progression of retinopathy. Our study demonstrates that a high degree of metabolic control delays, and may prevent, microvascular changes, and confirms other studies indicating that most postpubescent, insulin-dependent diabetic patients will develop retinopathy within 15 years unless a relatively high degree of control is maintained.