Fluorescein transport through the blood-aqueous and blood-retinal barriers in diabetic macular edema

PURPOSE: To investigate the integrity of the blood-aqueous barrier (BAB) and the blood-retinal barrier (BRB) in diabetic patients with clinically significant macular edema (CSME). METHODS: The rate constant (Kd(F)) of the BAB and the permeability of the blood-retinal barrier for non-protein bound fluorescein were determined simultaneously by fluorometry. Results were analysed pairwise in diabetic patients (n = 25) with CSME in one eye and without CSME in the other eye. RESULTS: Kd(F) for the eyes with CSME was significantly increased compared to eyes without CSME (444. 10(-6) min( -1) and 387. 10(-6) min(-1) respectively, p = 0.01). The passive permeability of the BRB was also significantly increased in CSME (5.7 nm/sec and 3.5 nm/sec respectively, p = 0.009, n = 19). CONCLUSIONS: Both the rate constant of the BAB and the BRB permeability were significantly increased in CSME indicating that eye-specific factors are common for both barriers in diabetic patients with CSME.