Known as the leading cause of blindness in the U.S., the war against glaucoma rages on. However, doctors say the best defense is early detection.

"Patients don't really come in with complaints of glaucoma, usually you find it when you come in on a routine eye exam," says ophthalmologist, Dr. Jason Read.

A disease which affects the optic nerve inside the eye, Dr. Read says glaucoma can occur in people from the cradle to the grave. However, it's most common in people over 50. Common in African Americans and people who have a family history of the disease, he says it can often go undetected for quite some time.

"Because you can have 20-20 vision right until the very end because your side vision is what's affected first."

Another common cause is the pressure level in the eye. When it comes to pressure in the eye, Dr. Read says you should think of a balloon which is filled with pressure. The eye is similar. However, instead it's filled with water pressure. Here's how it works: the higher the risk, the higher your chances of glaucoma. On the other hand, the lower the pressure, the lower the risk.

While yearly eye exams are recommended, Read says not catching glaucoma early can be costly with a price of losing your sight.

"If the pressure inside the eye is really high, it could take just days but usually it’s a disease that takes time over years."

Because there is not a cure for glaucoma, doctors say once the damage is done, there's no way to repair it. However, the good news is that medication is available to keep the vision from getting any worse, just one more reason to help everyone clearly see the importance of annual checkups.

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