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.