Outflow facility studies in the perfused human ocular anterior segment.

Abstract We have recently developed a tissue model of the human aqueous outflow pathway involving placement of the eviscerated anterior corneoscleral shell, [with lens and uveal tissue removed but trabecular meshwork (TM) attached] onto a specialized perfusion apparatus. The TM and associated outflow tissues are perfused with culture medium at a physiologically-relevant perfusion pressure in a 5% CO 2 environment at 37°C. Under these conditions, the perfused outflow tissues are similar for several days, to the human and/or subhuman primate outflow system in vivo with regard to morphology as well as several functional parameters. Measured facility of outflow (0·271±0·018 μl min −1 mmHg −1 , n = 79) is similar to facility values obtained by tonography in living human beings. Moreover, outflow facility decreases in a linear fashion with increased perfusion pressure by 1·4% mmHg −1 . Finally the removal of the TM results in a 41% decrease in measured outflow resistance. The ability to study viable human outflow tissue for at least several days and the opportunity to establish a model which serves as an alternative to animal testing, point to the potential importance of this technique in investigating the biology of the aqueous outflow system.