Investigative Ophthalmology & Visual Science, Vol 34, 385-394, Copyright © 1993 by Association for Research in Vision and Ophthalmology

ARTICLES AND REPORTS

Retroperfusion studies of the aqueous outflow system. Part I: Evaluation of technique using N-ethyl maleimide

CR Ethier, FM Coloma, AW de Kater and RR Allingham
Institute for Biomedical Engineering, University of Toronto, Ontario, Canada.

PURPOSE. The goal of this study was to develop a new technique to deliver drugs or other agents to the lumen of the angular aqueous plexus/Schlemm's canal (AAP/SC) while bypassing the trabecular meshwork, thereby gaining insight into AAP/SC inner wall function. METHODS. The anterior chamber is held at a small negative pressure and fluid is allowed to flow retrograde from the limbal vessels, through the collector channels, and into the AAP/SC ("retroperfusion"). Facility measurements are combined with histologic and tracer studies in bovine eyes. RESULTS. (1) Retroperfusion with a saline solution does not alter facility or change outflow pathway morphology; (2) fluid is able to move retrograde from the scleral surface and enter the lumen of the AAP; and (3) retroperfusion with N-ethyl maleimide causes a dose- dependent increase in washout rate and concomitant inner wall breaks. CONCLUSIONS. It is hypothesized that the observed increase in washout is due to leakage of extracellular materials through breaks in the inner wall.