Glaucoma is a group of eye disorders that damage the optic nerve, leading to irreversible vision loss. It often has no symptoms in its early stages, making it dangerous. In most cases, glaucoma is associated with higher-than-normal pressure inside the eye, a condition called ocular hypertension. But it also can occur when intraocular pressure (IOP) is normal. If untreated or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to blindness. There are many options for treating glaucoma, from routine eye drop therapy to laser surgery or the insertion of medical devices in the eye that help relieve pressure.