We used slit-lamp fluorophotometry to evaluate the influence of various intraocular lens fixation sites on the blood-aqueous barrier in 106 eyes. After an average follow-up period of 1.1 years, eyes with anterior chamber lenses with closed or rectangular loops had a significantly higher concentration of fluorescein than did eyes with other types of implants (P less than .1 to P less than .001). In eyes with posterior chamber lenses, those with ciliary sulcus fixation had a significantly higher concentration of fluorescein than did those with intracapsular fixation (P less than .02). Compared with aphakic eyes without implants, eyes with any implant other than posterior chamber lenses with intracapsular fixation had significantly higher fluorescein concentrations (P less than .02 to P less than .001). These results indicated that the flexibility and the intraocular location of the lens loops are significant factors in securing the integrity of the blood-aqueous barrier of pseudophakic eyes. Posterior chamber lenses with intracapsular fixation caused the least trauma to the blood-aqueous barrier.