Matrix metalloproteinases (MMPs) are a group of endopeptidases with the role of reorganizing the extracellular matrix of cells through the body. In aqueous humor MMPs have an important role in turnover regulation by acting on the constant remodeling of the trabecular mesh keeping at a constant level the trabecular resistance for a good aqueous humor outflow and consequently of the intraocular pressure. In this paper, we aimed to assess the levels of MMP-2/TIMP-1 and MMP-9/TIMP-2 ratio in aqueous humor samples and in the plasma of patients with open angle glaucoma and cataract patients that serves as control, and to evaluate the gelatinolytic activity MMP-2 and MMP-9 in aqueous humor samples. Aqueous humor and plasma samples were collected from 30 patients, 14 from open angle glaucoma and 16 from cataract patients. Levels of MMP-2, -9 and TIMP -1 and -2 were determined by zymography and immunoassays, using specific kits. The data obtained suggest the presence of a direct correlation between the levels and activity of MMP influencing the accumulation of abnormal matrix and may have an impact on the pathogenesis of open angle glaucoma.