The goal of the study was to determine vitrectomy effect on ocular hydrodynamics. Patients were divided into 2 groups: patients with diabetes mellitus (DM) were enrolled in the 1st group, indications for vitrectomy were vitreous hemorrhage or diabetic macula edema. The 2nd group included patients without DM, indications for vitrectomy were macula hole, epiretinal fibrosis. Electronic tonography was used to measure the main ocular hydrodynamic parameters before and 2-12 months after the surgery. Though intraocular pressure (IOP) increased after vitrectomy in all patients, the true IOP was normal in the majority of them (60%) and did not require medical correction. In the rest of cases IOP increase required medical treatment: in 23% during 1 month, in 11% during 6-12 months. In subsequent follow-up during 2 years no glaucoma signs were revealed.