Glaucoma causes the gradual loss of peripheral, or side vision. Although linked to older age, glaucoma may develop at any age - even infancy.
The cause of glaucoma is unknown, but a number of risk factors have been identified. These include age, heredity, myopia (near-sightedness), increased pressure inside the eye, and systemic disease such as diabetes and hypertension. Vision loss from glaucoma may be caused by increased IOP and other influences on the optic nerve, located at the back of the eye. The diminishing nerve function causes loss of peripheral vision painlessly and without notice.
It is important to be aware of the possibility of glaucoma, particularly if you have any of the risk factors. Some drugs, such as cortisone (steroid) drops, can cause glaucoma. Some visual disturbances that cannot be corrected by glasses may be a sign of glaucoma.
In the vast majority of cases, especially in the early stages, there are few signs or symptoms. In the later stages of the disease, symptoms can occur and include loss of side vision, an inability to adjust the eyes to darkened rooms, difficulty in focusing on close work, rainbow colored rings around lights and frequent changes of prescription glasses.