It is the presence of an intraocular pressure, less than 6 mm Hg or due to the existence of an IOP below a level, which implies functional and structural changes that prevent the normal functioning of the eye. It occurs in various clinical circumstances and can be due to reversible or irreversible causes. They are usually unilateral ocular processes, the majority during the immediate postoperative period after glaucoma surgery.

Treatment: they usually appear secondary to ocular surgery; the ideal is to surgically correct the initial problem.