Glaucoma refers to a group of related eye disorders that all cause damage to the optic nerve that carries information from the eye to the brain. Glaucoma usually has few or no initial symptoms. 
In most cases, glaucoma is associated with higher-than-normal pressure inside the eye. But it also can occur when intraocular pressure (IOP) is normal. If untreated or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to blindness.
Types and Symptoms of Glaucoma
Primary open-angle glaucoma. This common type of glaucoma gradually reduces your peripheral vision without other symptoms. By the time you notice it, permanent damage already has occurred. If your IOP remains high, the destruction can progress until tunnel vision develops, and you will be able to see only objects that are straight ahead. Ultimately, all vision can be lost, causing blindness.
Acute angle-closure glaucoma. Also called narrow-angle glaucoma, acute angle-closure glaucoma produces sudden symptoms such as eye pain, headaches, halos around lights, dilated pupils, vision loss, red eyes nausea and vomiting.
Normal-tension glaucoma. Normal-tension glaucoma is a type of open-angle glaucoma that can cause visual field loss due to optic nerve damage. But in normal-tension glaucoma, the eye’s IOP remains in the normal range. Also, pain is unlikely and permanent damage to the eye’s optic nerve may not be noticed until symptoms such as tunnel vision occur. The cause of normal-tension glaucoma is not known. Many doctors believe it is related to poor blood flow to the optic nerve. Normal-tension glaucoma is more common in those who are Japanese, are female and/or have a history of vascular disease.
Congenital glaucoma. This inherited form of glaucoma is present at birth, with 80 percent of cases diagnosed by age one. These children are born with narrow angles or some other defect in the drainage system of the eye. It’s difficult to spot signs of congenital glaucoma, because children are too young to understand what is happening to them. If you notice a cloudy, white, hazy, enlarged or protruding eye in your child, consult your eye doctor.
