Intraocular pressure elevation precedes a phagocytosis decline in a model of pigmentary glaucoma

Abstract

PurposeOutflow regulation and phagocytosis are key functions of the trabecular meshwork (TM), but it is not clear how the two are related in secondary open angle glaucomas characterized by an increased particle load. We hypothesized that diminished TM phagocytosis is not the primary cause of early ocular hypertension and recreated pigment dispersion in a porcine ex vivo model.\n\nMaterials and MethodsSixteen porcine anterior chamber cultures received a continuous infusion of pigment granules (P), while 16 additional anterior chambers served as controls (C). Pressure transducers recorded the intraocular pressure (IOP). The phagocytic capacity of the trabecular meshwork was determined by fluorescent microspheres.\n\nResultsThe baseline IOPs in P and C were similar (P=0.82). A significant IOP elevation occurred in P at 48, 120, and 180 hours (all P0.05).\n\nConclusionIn this porcine model of pigmentary glaucoma, an IOP elevation occurs much earlier than when phagocytosis fails, suggesting that two separate mechanisms might be at work.