Types of Glaucoma and Their Causes

Glaucoma is a serious group of eye diseases that without treatment can result in blindness. It is the second leading cause of vision loss, with cataracts being number one. Oftentimes, these diseases will progress gradually, making it difficult to recognize by the individual. Except for the gradual loss of vision, no other signs or symptoms may be present. When glaucoma develops, it causes pressure to build up inside the eye, which can lead to optic nerve damage. Increased pressure within the eyes is due to the eye's natural fluid known as aqueous humor not exiting the eye as it should. As the fluid backs up in the eyes, pressure increases, causing the disease.

Primary Open-Angle
There are several types of glaucoma. The most common type is known as primary open-angle. This type results when a partial blockage of the microscopic aqueous humor drainage system occurs causing the fluid to drain too slowly from the eye. As this occurs, fluid builds up causing increased pressure, although it is a gradual increase. Without routine examinations, individuals can develop this disease and be completely unaware of it, as vision loss is so gradual. The cause of this type is unknown.

Angle-Closure
This form of glaucoma occurs suddenly resulting from the iris bulging forward, blocking the drainage system. When this occurs, pressure buildup is abrupt. Oftentimes, this is caused by the individual having too narrow of a drainage system that never caused previous problems. It therefore, often goes undetected. The abrupt blockage can occur due to sudden dilation of the pupils, which can occur from certain medications, routine eye dilation examinations or going from light to darkness.

Low-Tension
Low-tension glaucoma is another common type of this disease that causes optic nerve damage. Although eye pressure is not increased in the eye, the optic nerve still becomes damaged. It is not completely understood why this occurs, but some specialists believe it could be caused from poor blood flow to the optic nerve due to atherosclerosis.

Pigmentary
This form of glaucoma occurs in younger people due to pigment granules dispersing into the eyes. These granules are believed to develop in the back part of the iris and disperse into the drainage system causing the aqueous fluid to drain slower than normal. This results in increased pressure.

Early Diagnosis Can Prevent Blindness
Early diagnosis is key in preventing glaucoma from causing blindness. With early diagnosis, treatments can be provided to reduce or prevent the optic nerve from becoming damaged. Regular vision examinations that include measuring eye pressure should be done at least every two years by a qualified optometrist in WA.