Most of the other types of glaucoma are variations of open-angle or angle-closure types. These types can occur in one or both of your eyes.
Secondary Glaucoma can occur as the result of an eye injury, inflammation, tumor, or in advanced cases of cataract or diabetes. It can also be caused by certain drugs such as steroids. This form of glaucoma may be mild or severe. The type of treatment will depend on whether it is open-angle or narrow-angle glaucoma.
Normal-tension glaucoma (NTG) is also called low-tension or normal pressure glaucoma. In this type of glaucoma, the optic nerve is damaged even through the intraocular pressure (IOP) is not very high. Doctors do not know why some people’s optic nerves are damaged even though they have almost normal pressure levels. Those at higher risk for this form of glaucoma are people with a family history of normal-tension glaucoma, people of Japanese ancestry, and people with a history of systemic heart disease such as irregular heart rhythm.
Pigmentary glaucoma is a type of inherited open-angle glaucoma which develops more frequently in men than in women. It most often begins in the twenties and thirties, which makes it particularly dangerous to a lifetime of normal vision. Nearsighted patients are more typically afflicted. The anatomy of the eyes of these patients appears to play a key role in the development of this type of glaucoma.
Myopic (nearsighted) eyes have a concave-shaped iris which creates an unusually wide angle. This causes the pigment layer of the eye to rub on the lens. This rubbing action causes the iris pigment to shed into the aqueous humor and onto neighboring structures, such as the trabecular meshwork. Pigment may plug the pores of the trabecular meshwork, causing it to clog, and thereby increasing the IOP.
Miotic therapy is the treatment of choice, but these drugs in drop form can cause disabling visual blurring in younger patients. Fortunately, a slow-release form is available. Laser iridotomy is presently being investigated in the treatment of this disorder.
Congenital glaucoma occurs in babies. This is a rare condition that may be inherited. It is the result of incorrect or incomplete development of the eye’s drainage canals during the prenatal period. In an uncomplicated case, microsurgery can often correct the structural defects. Other cases are treated with medication and surgery.
A blow to the eye, chemical burn, or penetrating injury may all lead to the development of glaucoma, either acute or chronic. This can be due to a mechanical disruption or physical change within the eye´s drainage system. It is therefore crucial for anyone who has suffered eye trauma to have check-ups at regular intervals.
This common cause of glaucoma is found everywhere in the world, but is most common among people of European descent. In about 10% of the population over age 50, a whitish material, which looks on slit-lamp examination somewhat like tiny flakes of dandruff, builds up on the lens of the eye. This pseudoexfoliative material is rubbed off the lens by movement of the iris and at the same time, pigment is rubbed off the iris. Both pigment and pseudoexfoliation material clog the trabecular meshwork, leading to IOP elevation, sometimes to very high levels.
Pseudoexfoliation syndrome can lead to both open-angle glaucoma and angle-closure glaucoma, often producing both kinds of glaucoma in the same individual. Not all persons with pseudoexfoliation syndrome develop glaucoma. However, if you have pseudoexfoliation syndrome, your chances of developing glaucoma are about six times as high as if you don´t. It often appears in one eye long before the other, for unknown reasons. If you have glaucoma in one eye only, this is the most likely cause. It can be detected before the glaucoma develops, so that you can be more carefully observed and minimize your chances of vision loss.
*Information courtesy of Glaucoma Research Foundation