Permeability of the blood-ocular barrier in adolescent and adult diabetic patients.

The permeability of the blood-ocular barrier was examined by fluorophotometry in adolescent and adult diabetic patients before the onset of retinopathy. The adolescent group consisted of 52 eyes of 52 insulin dependent diabetic patients aged 11 to 19 years and a control group of 10 eyes of 10 normal adolescents. The adult group consisted of 74 eyes of 74 non-insulin dependent diabetics and a control group of 30 eyes of 30 normal adults. The increase in lens autofluorescence in the adolescent diabetic patients compared with the controls was striking and showed a significant positive correlation (r = 0.79, p < 0.0001) with the duration of diabetes. Anterior chamber (AQ) values, an index of the permeability of the blood-aqueous barrier (BAB), increased in the adolescent diabetic patients compared with the controls and showed a significant positive correlation with glycosylated haemoglobin levels. No significant differences from the controls were observed regarding the permeability of the blood-retinal barrier (BRB). In the adult group there was no significant difference in either the permeability of the BRB or the AQ values between the diabetic and the control groups. Our results suggest that adolescent diabetic patients differ from adults in that BAB permeability is increased before the onset of retinopathy, suggesting that this is the cause of the striking increase in lens autofluorescence.