Glaucoma is optic nerve damage, typically due to elevated internal eye pressure. If enough optic nerve damage occurs over a long enough period of time, the peripheral vision begins to dim. The end result of this dimming is known as “tunnel vision”, and can result in legal blindness. Fortunately, the majority of cases of Glaucoma take a long time to cause vision loss, but every person over 40 should be checked for it annually. Most cases of Glaucoma can be controlled with medicated eye drops, and sometimes, surgery in special cases.