CHAPEL HILL, N.C. -- Glaucoma is the second leading cause of blindness, but many people worry they will not be able to tell if they have it.

According to doctors, a little awareness about the serious eye disease can go a long way.

"People can go absolutely stone blind from glaucoma," said Dr. Sandra Johnson, an ophthalmologist at UNC HealthCare.

Johnson explained that a healthy eye produces a thin fluid that provides nutrients. The fluid passes through the pupil and drains.

When glaucoma develops, the fluid gets trapped and the buildup increases pressure, damaging nerves. Over time, the condition destroys vision.

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Johnson said there are no symptoms when glaucoma begins.

When symptoms begin to appear, Johnson said it begins with blurred vision. If it goes untreated, people lose peripheral vision next. Eventually, all vision is lost.

"By the time a patient is aware that they're losing vision, they often will go blind within several months. It's very, very rapid at the end," Johnson said.

Johnson said glaucoma can be detected early with regular eye exams.

"It's really an eye disease where early detection and early treatment make a big difference," said Johnson.

Glaucoma is treated with eye drops or, in more severe cases, laser surgery.

Those considered at high risk for glaucoma include people over the age of 50, people with diabetes and people with a family history of glaucoma.

Glaucoma is also most common and develops earlier among African-Americans.