The second annual ARVO/Pfizer Ophthalmic Research Institute conference was held Friday and Saturday, April 28 and 29, 2006, at the Fort Lauderdale Grande Hotel and Yacht Club, Fort Lauderdale, Florida. The conference, funded by The ARVO Foundation for Eye Research through a grant from Pfizer Ophthalmics, provided an opportunity to gather experts from within and outside ophthalmology to develop strategies to improve research and clinical care in areas of ophthalmology related to preventable vision loss and blindness. This year’s conference focused on aqueous humor outflow. A working group of 31 researchers on aqueous outflow, 8 scientists working on interests other than aqueous humor outflow but with expertise in areas relevant to the field, and 11 observers from ARVO, Pfizer, and clinical and basic ophthalmic research convened on April 28, 2006, to evaluate the current understanding of the aqueous humor outflow pathway. The goals were to compare similarities between ocular aqueous humor outflow and fluid flow in other tissues of the body, to critique conventional ideas, to identify the most important scientific questions, and to discuss strategies to answer these questions. The meeting format emphasized discussion and concentrated on questions within four general areas of outflow research: Session I: Conventional Outflow: Cell Function in the Aqueous Humor Outflow Pathway Session II: Conventional Outflow: Role of the Extracellular Matrix Session III: Uveoscleral Outflow: The Other Pathway Session IV: Normal Versus Primary Open Angle Glaucoma (POAG): What Is the Cause of Elevated Pressure? Each session began with a 10-minute overview by an outflow researcher followed by a 30-minute talk by one of the outside experts. Parallels between their fields of expertise and the eye were included in these talks. Invited outside experts covered several areas of research, including vascular endothelial cell biology (Peter Davies, PhD, University of Pennsylvania, Philadelphia), matricellular proteins (Paul Bornstein, MD, University of Washington, Seattle), renal and lymphatic biology (Donatscho Kerjaschki, MD, University of Vienna, Austria, and David Zawiega, PhD, Texas A & M University, College Station, Texas), oxidative damage mechanisms (James Mitchell, PhD, National Institutes of Health, Bethesda, Maryland), advanced glycation end-products and aging (Alan Stitt, PhD, Queens University, Belfast, Northern Ireland), cell adhesion (Benjamin Geiger, PhD, Weizmann Institute of Science, Rehovot, Israel), and cellular tight junctions (Eveline Schneeberger, MD, Massachusetts General Hospital, Boston, Massachusetts). The remainder of each session was used to discuss questions pertinent to the main topic and provided an opportunity for attendees to voice their opinions and work together to define questions that are still unanswered. The lively discussions were successful in defining old and new ideas that are essential to a better understanding of aqueous humor outflow. This conference summary highlights the ideas discussed and introduces areas that need further exploration.