Changes in aqueous outflow after in vitro neodymium: yttrium aluminum garnet laser cyclophotocoagulation

To examine the possible role of transscleral outflow routes, enucleated human and porcine eyes underwent noncontact neodymium:yttrium aluminum garnet (Nd:YAG) laser cyclophotocoagulation 3 mm posterior to the limbus. Pars plana lesions were verified histologically. The eyes were perfused with saline solution at 50 mm Hg perfusion pressure, placing the tip of the needle into the hyaloid orbicular space. The outflow facility was 0.072 microliter/min/mm Hg in paired controls and 0.105 microliter/min/mm Hg in human lasered eyes, a difference of 31%. In porcine eyes the difference was 43%. Since concepts of aqueous production, impaired circulation, and inflammation do not apply to enucleated eyes, the increase may be related to pars plana transscleral flow facilitated by disruption of the neuroepithelial barrier.