To study the early ocular abnormalities in young diabetic patients, corneal and lens autofluorescence was measured by fluorophotometry in 30 eyes of 30 insulin-dependent diabetic patients without retinopathy. The lens [f(l)] and the corneal [f(c)] autofluorescence values in diabetic patients were significantly higher than in controls. In diabetic patients, f(l) was significantly correlated with the duration of diabetes, the f(c) was significantly correlated with the duration of diabetes and the indices of metabolic control, i.e. HbA1c and fructosamine. Our study demonstrated that young diabetic patients clearly had corneal and lens abnormalities before the appearance of overt diabetic retinopathy. The f(c) value might be a good indicator of metabolic control in diabetic patients.