Primary Open Angle Glaucoma: Glaucoma occurs in several forms. The most common of these, primary open-angle glaucoma, develops when the drainage system allowing aqueous humor to leave the eye is blocked. This form of glaucoma progresses gradually, and can be asymptomatic until vision is already damaged. This type of glaucoma appears to run in families and certain ethnic groups, affecting African Americans more frequently than those of European descent.
Ocular Hypertension: A precursor to the development of glaucoma, ocular hypertension is a condition in which pressure in the eye is high, which may predispose an individual to develop glaucoma with the accompanying damage to the optical nerve.
Angle-Closure Glaucoma: Angle closure glaucoma occurs when the drainage channels in the eye become completely blocked, causing a sudden rise in intraocular pressure that can lead to immediate vision loss. This type of glaucoma requires emergency treatment to prevent permanent damage to the optic nerve.
Normal-Tension Glaucoma: Although a rise in IOP generally accompanies glaucoma, for unknown reasons, some people with normal intraocular pressure can also develop the disease. Normal pressure glaucoma can cause lasting eye damage since it may go undetected due to the lack of high IOP.
Pigmentary Glaucoma : Pigmentary glaucoma occurs when pigment in the retina or iris detach and block the outflow of aqueous humor. Often seen in younger patients, this type of glaucoma can lead to highly elevated intraocular pressure.
Exfoliation Glaucoma: Flakes of material in the front of the eye can also detach and block the drainage of fluids from the eye. Called exfoliation glaucoma, this form of the disease can occur with either open or closed angle glaucoma and causes a rise in intraocular pressure.
Congenital Glaucoma: Congenital glaucoma is present in infants. This type of glaucoma is often associated with abnormal development of the eye itself, and also has a hereditary component.
Secondary Glaucoma: Secondary glaucoma is caused by other factors, such as medications. Corticosteroids and other drugs, including dilating eye drops, can cause an increase in intraocular pressure that leads to damage in the optic nerve. Glaucoma can also develop as a result of a variety of systemic diseases, and also from trauma to the eye area, such as a blow that damages eye tissues.