January is National Glaucoma Awareness Month. It is an important time to spread the word and raise awareness about glaucoma, which is considered a thief of sight. There are virtually no symptoms associated with the disease and once vision is lost, it is gone for good. As much as 40% of one's vision can be lost before a change is noticed. This condition is considered the leading cause of preventable blindness. 

There is no cure for glaucoma but with early detection, medication or surgery, it can be slowed down and further vision can be prevented. Over 2.7 million Americans, and over 60 million people worldwide, have glaucoma. Experts estimate that half of these individuals do not even know they have the disease. With these numbers growing it is very important to receive regular eye examinations. 

What is glaucoma?

There are two main types of glaucoma. First is primary open-angle glaucoma and the second type is angle-closure glaucoma. These are marked by an increase of intraocular pressure, or pressure inside the eye. Secondary glaucoma refers to any case in which another disease causes or contributes to increased eye pressure.

In a healthy eye, clear fluid is constantly being made behind the iris and leaving the eye through a microscopic drainage canal in the front of the eye. If this drainage channel becomes blocked, the pressure inside the eye goes up and often causes glaucoma damage to the optic nerve. This is the nerve that connects the eye to the brain so damage to it causes loss of vision. 

Who is at risk?

While the causes of glaucoma are not completely known, risk factors for its development include a family history of glaucoma, race and older age. Glaucoma may affect people of any age from newborns to the elderly, but is more common in adults as they approach their senior years. African-Americans, Hispanics and people with diabetes are also at increased risk of developing the disease.