Glaucoma is a group of eye diseases that lead to damage of the optic nerve, which transmits visual information from the eye to the brain. Glaucoma may cause vision loss if left untreated. It has been called the "silent thief of sight" because the loss of vision usually occurs slowly over a long period of time.^[5] A major risk factor for glaucoma is increased pressure within the eye, known as intraocular pressure (IOP).^[1] It is associated with old age, a family history of glaucoma, and certain medical conditions or medications.