More complicated than a single disease.
Glaucoma is a group of eye conditions that damage the optic nerve. The damage can be progressive and irreversible, resulting in a partial or total loss of vision, making glaucoma a leading cause of blindness in the United States. The damage can occur gradually, with the person not noticing a loss of vision until the disease is at an advanced stage. This is true of the most common type of glaucoma, primary open-angle glaucoma.
Primary Open-Angle Glaucoma
Progressive clogging of the eye’s drainage canals creates progressive inner eye pressure if enough fluid doesn’t drain. The slow development of the disease provides no symptoms or early warning signs, making detection difficult for the three million Americans affected. Sufferers may not notice vision loss for many years. The condition usually responds well to medication, especially if caught and treated early. If not diagnosed and treated, it can cause a gradual loss of vision.
Also called narrow-angle glaucoma, this rare disease is often accompanied by a rapid rise in eye pressure due to blockage of the drainage canals. Symptoms include headaches, eye pain, nausea and blurred or halo vision. Laser surgery to unblock the drainage canals is often used with successful and long-lasting results.
In this condition the optic nerve is damaged despite near-normal eye pressure. Doctors do not know why some people’s optic nerves are damaged even though they have normal eye pressure levels. People with family histories of normal-tension glaucoma and systemic heart disease are at risk. Diagnosis is evolving with knowledge of the disease and typically involves observing the optic nerve for signs of damage via instrumentation and vision field tests. Treatment typically involves medication and laser or conventional surgery to relieve eye pressure.
In this condition another disease causes or contributes to increased eye pressure, damaging the optic nerve and leading to a loss of vision. Eye injury, inflammation and tumors are primary causes, as are advanced cases of cataracts and diabetes. The resulting glaucoma may be open-angle or angle-closure types noted above. Treatment will depend on the type of glaucoma and its severity.
This form of secondary open-angle glaucoma occurs when pigment granules in the iris seep into the fluid inside the eye. In time the granules clog the drainage canals, causing eye pressure to rise. Treatment typically involves medication and laser or conventional surgery to relieve eye pressure.
Another form of secondary open-angle glaucoma, this condition occurs when the outer layer of the iris flakes and collects in the eye’s drainage system, causing eye pressure to rise. Treatment typically involves medication and laser or conventional surgery to relieve eye pressure.
Eye injuries are a leading cause of secondary open-angle glaucoma. The glaucoma often occurs immediately following the injury, but can also appear many years later. Blunt trauma that bruises the eye and injuries that penetrate the eye are typically involved.
New blood vessels forming on the iris and over the eye’s drainage system can block fluid from draining, causing eye pressure to rise. This form of secondary open-angle glaucoma is always associated with diabetes or other abnormalities and is among the most difficult to treat.
Irido Corneal Endothelial Syndrome (ICE)
Typically occurring in one eye, anterior cornea cells spread over the eye’s drainage tissue, causing eye pressure to rise and threatening damage to the optic nerve. The cells bind to the iris, increasing blockage. Symptoms include halo and hazy vision. Treatment typically involves medication and conventional surgery to relieve eye pressure.
Congenital Glaucoma (Childhood Glaucoma)
Occurring in one out of every 10,000 births in the United States, this glaucoma is caused when blocked or defective drainage canals cause an abnormal drainage from the eye. It is often hereditary or developed during pregnancy. The abnormal drainage may also be the result of some other eye disease. Treatment typically involves medication and laser or conventional surgery to relieve eye pressure.