UNLABELLED: Glaucoma causes trabecular meshwork and Schlemm canal changes, resulting in the obstruction of the aqueous flow at this level. AIM: To show the histological changes in the surgically removed trabecular meshwork tissues. MATERIAL AND METHOD: Trabecular meshwork fragments were histologically processed for histological diagnosis. RESULTS: 29.87% of all patients had ordered structure with high eosinophilia, 20.12% a rare structure with high eosinophilia, 21.34% a voluminous trabecular meshwork with fusiform cells, 21.03% tissue fibrosis and 7.62% had tissue necrosis. CONCLUSIONS: Aqueous flow obstruction in trabecular meshwork is produced by the histological changes at this level, found in all tissue specimens removed during surgery.