We established and validated an in toto method to perform TdT-mediated dUTP nick end labeling to study apoptosis in human trabecular meshwork tissue obtained during trabeculectomy in glaucoma patients. In specimens from patients with primary open-angle glaucoma and primary angle-closure glaucoma, we detected a tendency for more apoptotic cells to accumulate in patients with primary open-angle glaucoma. The utility of this method to study apoptosis in the trabecular meshwork is discussed, as well as its application as a tool in biologic samples.