Biphasic fluorescence decay in kinetic vitreous fluorophotometry

Eyes of 15 normal subjects and 24 diabetic patients underwent kinetic vitreous fluorophotometry at five, six, eight, ten, 24, and 48 hours after intravenous administration of sodium fluorescein 10 mg/kg. Exponential decay constants (Kv) were calculated for the period between five and 24 hours (Kv1) and for that between 24 and 48 hours (Kv2). In normal subjects and diabetic patients with background retinopathy, Kv1 was larger than Kv2, indicating biphasic fluorescence decay. However, in patients with proliferative retinopathy, Kv1 was significantly smaller than in other subjects, so Kv1 - Kv2 was smaller than that of the controls.