Glaucoma is a term describing a group of ocular disorders with multi-factorial etiology united by a clinically characteristic intraocular pressure-associated optic neuropathy. And unfortunately approximately 10% of people with glaucoma who receive proper treatment still experience loss of vision. This can permanently damage vision in the affected eye(s) and lead to blindness if left untreated. It is normally associated with increased fluid pressure in the eye (aqueous humour). The term "ocular hypertension" is used for people with consistently raised intraocular pressure (IOP) without any associated optic nerve damage. Conversely, the term 'normal tension' or 'low tension' glaucoma is used for those with optic nerve damage and associated visual field loss, but normal or low IOP. The first sign of glaucoma is often the loss of peripheral or side vision, which can go unnoticed until late in the disease. Detecting glaucoma early is one reason you should have a complete exam with an eye specialist every one to two years. Occasionally, intraocular pressure can rise to severe levels. In these cases, sudden eye pain, headache, blurred vision, or the appearance of halos around lights may occur. The eye exam typically focuses on the optic nerve which has a particular appearance in glaucoma. Glaucoma treatment may include prescription eye drops, laser surgery, or microsurgery. Open-angle glaucoma is most commonly treated with various combinations of eye drops, laser trabeculoplasty, and microsurgery. Traditionally in the U.S., medications are used first, but there is increasing evidence that some people with glaucoma may respond better with early laser surgery or microsurgery.