Vitreous fluorophotometry in juvenile diabetics with and without retinopathy in relation to metabolic control: insulin antibodies and c-peptide levels.

Vitreous fluorophotometry was performed in 56 juvenile insulin-dependent diabetic patients aged 9-23 years (median: 16 years), diabetes duration 1-20 years (median: 8 years). Fundus photography showed mild background retinopathy in 5 patients, while 51 patients had no signs of retinopathy. Abnormal leakage into the posterior vitreous body was found in 4/5 patients with background retinopathy and in 24/51 with normal fundi. We found a significantly positive correlation between abnormal leakage and duration of diabetes and HbA1 with Kendall rank-order correlation coefficients T = 0.21 (P = 0.01) and 0.19 (P = 0.02) resp. No significant correlation was found between leakage and age, actual blood glucose level or insulin antibodies expressed as insulin binding capacity of IgG, but a significantly negative correlation between abnormal leakage and low levels of fasting c-peptide/s T = 0.437 P less than 0.001. Kendall partial rank-order correlation analysis showed that c-peptide/s significantly explained the leakage when HbA1 or duration was kept constant. Duration could only explain leakage when HbA1 was fixed but not when c-peptide/s was kept constant. HbA1 could also explain leakage when duration or c-peptide was fixed.