Quantitative assessment of postsurgical breakdown of the blood-aqueous barrier

Breakdown and reestablishment of the blood-aqueous barrier (BAB) following experimental surgical trauma was evaluated by anterior segment slitlamp fluorophotometry. Substantially more fluorescein leakage was caused by 6-mm limbal incisions for at least the first four postoperative days than was produced by 3-mm incisions. Following 3-mm corneal incisions, leakage of fluorescein closely paralleled that of fluorescein-labeled dextran 70 (molecular weight, 70,000) for the first three postoperative days. On the fourth postoperative day, the BAB appeared reestablished to fluorescein-labeled dextran 70 but was still abnormally permeable to fluorescein. Thus, it appears that although fluorescein is the most sensitive technique of demonstrating breakdown of BAB, it may not always be an indicator of large-molecule permeability.