Glaucoma is a serious eye condition that can lead to blindness if it's not treated. It's much more common for elderly people to develop glaucoma than younger people.
Glaucoma is usually caused by fluid building up in the eye and increasing the pressure on the optic nerve. Although glaucoma causes a lot of the blindness in people older than 60, it's almost always treatable if it's diagnosed early enough. The word glaucoma comes from the Greek glaukoma, "opacity of the lens," from the root glaukommatos, "gray-eyed."