Оphthalmic manifestations of diabetes mellitus include changes in the circulation of aqueous humor, increase or decrease in the level of intraocular tension, abnormal permeability of the blood-aqueous barrier, and anomalies of the retinal vessels. A balanced approach to the choice of treatment tactics is a basis for treatment of Primary Open Angle Glaucoma. The criterion for the effectiveness of glaucoma surgery is sustained normalization of intraocular tension and preservation of visual functions. Surgical treatment of glaucoma in patients with severe somatic pathology is accompanied by a high risk of postoperative complications: hyphema, ciliochoroidal detachment, hemophthalmos, repeated increase in intraocular tension, etc. Diabetes mellitus as a systemic disease causes widespread vascular autonomic and endothelial dysfunction. The reasons for the decrease in the hypotensive effect of glaucoma surgery in such patients is excessive cicatrization of the newly created fluid outflow tracts with the formation of adhesions between the conjunctiva and the sclera, the scleral flap and underlying tissues. It leads to a repeated increase in intraocular tension in the late postoperative period. Therefore, the choice of tactics for the management and treatment of patients with glaucoma and with severe comorbidity requires an individual and measured approach.