Glaucoma is a group of eye diseases, marked by increased pressure within the eyeball, that gradually steals sight without warning and often without symptoms. If left untreated, vision loss is caused by damage to the optic nerve. This nerve acts like an electric cable with over a million wires and is responsible for carrying the images we see to the brain.
It was once thought that high intraocular pressure (IOP) was the main cause of this optic nerve damage. Although IOP is clearly a risk factor, we now know that other factors must also be involved because even people with “normal” IOP can experience vision loss from glaucoma.