Drainage devices have been using in the treatment of refractory glaucoma for more than 40 years. They give possibility for effective control of intraocular pressure in eyes, where natural outflow is totally blocked. Superiority of drainage systems such as Ahmed valve or Molteno device over other methods of normalization of intraocular pressure is due its effectiveness in eyes with high intraocular pressure and possibility of its use in eyes with higher risk of intraocular hemorrhage, which are observing ie. in patients with diabetic complications of the eye. A high intraocular pressure in eyes with increasing eye healing processes, mainly observed in children or in eyes with recurrent inflammation are contraindicated to treat using typical trabeculectomy procedure, because of its high ineffectiveness and therapy using diode laser should be recommended as a last choice of treatment of glaucoma. Proper diagnosis and the introduction of appropriate treatment methods at the right time significantly reduces the risk of vision loss due to glaucoma.