Glaucoma usually affects side (peripheral) vision first. If glaucoma isn't treated, vision loss will continue, causing total blindness over time. If glaucoma is found early and treatment starts right away, good eyesight can usually be maintained.

Treatment for any type of glaucoma may delay or prevent further vision loss. But treatment can't reverse vision loss that has already occurred. In a few rare cases of congenital glaucoma, treatment has reversed some damage to the optic nerve.

How much your life will be affected depends on your lifestyle and on how bad your vision loss is. Normal use of your eyes (such as for reading or watching TV) won't speed up vision loss or make the condition worse. For information on how to live with low vision, see Home Treatment.

Open-angle glaucoma (OAG)

OAG usually affects both eyes at the same time. But one eye may be affected more than the other.

Vision changes so slowly that much of your eyesight may be affected before you notice the condition. Blind spots from each side of the field of vision gradually meet, increasing the area of blindness. Central vision, used for reading and seeing details, is affected last.

Closed-angle glaucoma (CAG)

CAG usually affects only one eye at a time. It can happen suddenly (acute) or be a long-term problem. If it's acute, it's an emergency. Severe and permanent vision loss can develop within hours or days after symptoms start.

You may have short episodes of CAG. Without treatment, these episodes will keep coming back. They can become an emergency situation (acute closed-angle glaucoma) or a long-term problem (chronic closed-angle glaucoma).

Congenital glaucoma

Congenital glaucoma may be present at birth or develop within the first few years of life. Treatment needs to start right away to help avoid further vision loss and blindness. In certain children, some of the optic nerve damage caused by the disease can be reversed with treatment.