Myocilin (MYOC), also known as TIGR or GLC1A, is a secreted glycoprotein of the olfactomedin family, originally identified in trabecular meshwork cells after prolonged treatment with glucocorticoids, and, independently, in the retina. It may participate in the obstruction of fluid outflow in the trabecular meshwork. Defects in MYOC are the cause of primary open angle glaucoma (POAG). MYOC has a molecular weight of 55-57 kDa, besides, a 66-kDa form, which could be a result of post-translational modifications, has also been reported in some researches.