Glaucoma describes a group of diseases that lead to optic nerve damage from fluid buildup in the eye. In glaucoma, the aqueous humour, found between the lens and cornea of the eye, is unable to drain properly or is excessively produced. This buildup leads to increased intraocular pressure (IOP), which can then lead to optic atrophy. If glaucoma goes untreated or poorly managed, it can  cause  permanent and irreversible damage to vision, even to the extent of blindness.