Glaucoma is a chronic eye disease causing high intraocular pressure, either periodic, or constant, atrophy of the optic nerve (glaucomatose excavation) and changes in the visual field. Primary, secondary and congenital glaucomas are recognised. Primary glaucoma is preceded by trophic disturbances in the tissues of the forward eye department, especially in its drainage system, caused by changes in the eye vascular system and hemodynamics, as well as general pathological changes. This impairs the circulation of aqueous moisture and causes heightened intraocular tension. High intraocular tension results in secondary trophic changes in the eye tissues. The impairment of vision happens as a result of the atrophy of the retina and optic nerve functional elements. The disease is typical of people older than 40 years of age. In case of secondary glaucoma, changes in the intraocular liquid outflow tracts resulting in heightened intraocular tension are caused by different eye diseases (inflammatory and degenerative diseases of the eye tissues, a pathology of the lens, eye traumas, etc.). In case of congenital glaucoma, high intraocular pressure mainly arises from the impaired intraocular liquid outflow because of the mesoderm tissue blocking the angle of the forward chamber. There are two basic forms of primary glaucoma distinguished – open-angle and closed-angle. Open-angle glaucoma is associated with progressing degenerate changes in the eye drainage system. The disease development is usually latent and imperceptible for the patient. Patients, as a rule, have no subjective sensations. In certain cases, they may complain of a sensation of fullness in the eyes, headaches, misting of vision and iridisation. Visual changes in the eye are scarce. Examination may reveal the expansion of the forward ciliary arteries (the cobra symptom). Biomicroscopy may show dystrophy of the retina and solution of the eye pigmentary edge continuity. Gonioscopy exhibits that the angle is open. Closed-angle glaucoma is caused by the retina root blocking the angle of the forward chamber. In case of closed-angle glaucoma, patients complain of pain in the eye and headaches, misting of vision, iridisation and stagnation in the forward eye segment. The disease begins with an acute or subacute attack, which is accompanied by an acute pain in the region of the eye and the head, general malaise, nausea and vomiting. Expressed injection of the forward ciliary arteries is observed. The cornea is hydropic; the chamber is small; the pupil is mydriatic. The iris may be hydropic. Synechias and goniosynechias may form. Gonioscopy exhibits that the angle is completely closed. Intraocular pressure amounts up to 60-80 mm Hg. Vision is impaired sharply.