[Fluorophotometry as a method for the detection of permeability changes in the blood and aqueous humor barrier]

Abstract

The increase in permeability of the blood-aqueous barrier after Nd-YAG laser iridotomy and the protective effect of locally applied indomethacin were investigated in an experimental animal study using a computerized fluorophotometer. The permeability of the blood-aqueous barrier was evaluated by three different molecules: fluorescein-sodium (molecular weight 330), fluorescein-labeled dextran 70 000 (molecular weight 70 000) and fluorescein-labeled dextran 150 000 (molecular weight 150 000). The fluorescein concentration of the anterior chamber was measured in 36 eyes (18 rabbits) as well as in a control group of 9 eyes (9 rabbits) at fixed times after intravenous dye injection. Fluorescein leakage occurred, but no leakage of fluorescein-labeled dextrans was visible in the control group. Laser iridotomy induced a time-dependent increase in anterior segment permeability to fluorescein and fluorescein-labeled dextrans. Disturbance of the blood-aqueous barrier was effectively reduced by topical pretreatment with indomethacin, which mainly inhibited the leakage of the fluorescein-labeled dextrans. The clinical relevance of the laser-induced breakdown of the blood-aqueous barrier and the protective effect of a prophylactic pharmacotherapy are discussed.