Studies on the blood-aqueous barrier after argon laser photocoagulation of the iris

Breakdown and re-establishment of the blood-aqueous barrier (BAB) was studied following laser irradiation to the rabbit iris by quantitating leakage of protein, fluorescein, and fluorescein-labeled dextran (FLD-70, MW 70,000) into the aqueous humor. Breakdown of the BAB was more prolonged in pigmented than albino animals, possibly due to the increased laser energy absorbed by the pigmented iris. Fluorophotometry appeared to be a more sensitive method for evaluating BAB breakdown than aqueous protein measurements, and small molecule leakage (fluorescein) appeared to be more sensitive than macromolecule leakage (FLD-70). The noninvasive method of evaluating the BAB proved equally as effective as measuring aqueous protein content in assessing the sensitivity of laser-induced trauma to the ameliorating effect of the nonsteroidal anti-inflammatory agent indomethacin.