Glaucoma is an eye condition that occurs when there is an increase in eye pressure, often caused by a buildup of fluid. There are several different types of glaucoma, and with each there is a different reason for the fluid buildup. Each type has its own causes and symptoms as well.
Open-Angle Glaucoma
Open-angle glaucoma is the most common form of glaucoma. The Merck Manual Online Medical Library explains that with open-angle glaucoma, the eye's drainage canals become blocked. This progression can take months or years. As the canals become blocked and fluid drains very slowly, the fluid is still being produced, so the pressure in the eye begins to build up as well. This pressure can cause damage to the optic nerve. Symptoms develop slowly, starting with areas of vision loss until the vision becomes tunnel vision. If not treated, even tunnel vision will be gone, and blindness can set in.
Closed-Angle Glaucoma
Closed-angle glaucoma is also known as angle-closure glaucoma. In closed-angle glaucoma, for some reason the iris of the eye comes forward. According to the Mayo Clinic, as the iris comes forward it blocks the drainage route. When this happens, the increase in eye pressure happens quickly. Symptoms of the sudden increase in eye pressure are sudden pain in the eye, headaches, blurry vision, nausea, vomiting and the appearance of halos when looking at lights. While closed-angle glaucoma usually develops suddenly, in rarer instances it can take place gradually, in which case it is referred to as "chronic" closed-angle glaucoma.
Low-Tension Glaucoma
Low-tension glaucoma, also known as normal-tension glaucoma, is unlike the glaucomas mentioned above in the sense that the damage to the optic nerve is not caused by an increase in eye pressure. The Glaucoma Foundation explains that the damage is believed to be caused instead by poor blood circulation to the optic nerve, which can cause death to the cells that relay impulses from the retina in the eye to the brain. There are often no symptoms in low-tension glaucoma until it has progressed to the point where the afflicted begins to experience some loss of vision.
Pigmentary Glaucoma
Pigmentary glaucoma most often occurs in young people on up to middle age. The University of Michigan Kellogg Eye Center explains that with this type of glaucoma, the iris of the eye moves backwards--instead of forward as in low-tension glaucoma. This backward movement disturbs the eye pigment cells, which causes the pigment particles to be released into the eye's drainage canal, thereby blocking the drainage route and causing an increase in the pressure of the eye. Symptoms of pigmentary glaucoma are pain and blurry vision, usually after exercise such as jogging.
Congenital Glaucoma
Congenital glaucoma is a type of glaucoma that is found in infants. It is often caused by poor development of the infant's eye drainage canal. Eye pressure will increase and can result in a loss of vision. The Eye-Info Network suggests that since an infant cannot relate his eye problems to his parents, parents should look for symptoms of blurry or cloudy eyes.
