Glaucoma is a group of diseases that, as described by the National Eye Institute, damage the optic nerve of the eye and result in blindness. Glaucoma has many different forms, but each variant causes damage to the optic nerve, usually via increased fluid pressure in the eye. Treatment is dependent upon the type of glaucoma that the patient has contracted.
Primary Open Angle Glaucoma (POAG)
The Glaucoma Foundation estimates that 1 percent of all Americans suffers from Primary Open Angle Glaucoma (POAG). This makes it the most common type of glaucoma in the United States. There are no symptoms during the initial stages of POAG. The pressure rises, but the cornea, or transparent layer over the eye, adapts and prevents any visual symptoms. The pressure increase is gradual and the patient is usually unable to detect the loss of vision until late in the disease. The optic nerve is damaged when the pressure inside the eye exceeds 20 mmHg (normal is 14 to 16 mmHg). Treatment is a life-long regimen of medicines that decrease the pressure in the eye.
Angle Closure Glaucoma
Angle closure glaucoma is also called acute glaucoma or narrow angle glaucoma. This type of glaucoma affects nearly half a million Americans each year. The Glaucoma Research Foundation reports that it is different from open angle glaucoma in that the eye pressure rises rapidly. The pressure rises quickly because the normal fluid drainage of the eye is blocked or closed by the iris. Symptoms of angle closure glaucoma include headache, eye pain, nausea, visual illusions at night and very blurry vision. This condition is an emergency and requires prompt treatment.
Normal Tension Glaucoma
Normal tension glaucoma, or low tension glaucoma, is a condition where the optic nerve in the eye is damaged in patients with normal eye fluid pressure, according to the National Eye Institute. The symptoms are similar to open angle glaucoma because the pressure of the eye rises slowly. This disease may be due to decreased blood flow to the optic nerve. The Glaucoma Foundation has stated that the disease may be inherited. The Glaucoma Foundation also estimates that one-third of all POAG cases are actually misdiagnosed cases of normal tension glaucoma.
Congenital Glaucoma
Some children are born with a defect in the angle of the eye that results in a slow drainage of the fluid in the eye. This defect is termed congenital glaucoma by the National Eye Institute. The children experience cloudy eyes, sensitivity to light and excessive tearing. There is a safe and effective surgical procedure that can be done to relieve the pressure and permanently correct the condition.
Secondary Glaucoma
Glaucoma can be caused by eye injury, inflammation, a tumor, or in advanced cases of cataract (clouding of the lens of the eye) or diabetes. This type of glaucoma is termed secondary glaucoma by the Glaucoma Research Foundation. Drugs, like steroids, have also been shown to cause glaucoma. Examples of secondary glaucoma include pigmentary glaucoma (glaucoma that occurs when the pigment of the iris flakes off and blocks eye fluid drainage) and neovascular glaucoma (which is related to diabetes).
