My eye pressure is high. Does that mean I have glaucoma?

Eye pressure is measured in millimeters of mercury (mm Hg). Normal eye pressure ranges from 10-21 mm Hg. When your pressure is higher than 21 mm Hg, you are at an increased risk for developing glaucoma.
 
Some people can tolerate pressures slightly higher than normal without developing glaucoma. This is called ocular hypertension. If an ophthalmologist (a medical doctor who specializes in eye care and surgery) diagnoses ocular hypertension, it does not mean you have glaucoma, but it does mean you are at a higher risk for developing the condition, and you should be examined routinely to ensure no permanent optic nerve damage and vision loss occur.
 
On the other hand, some people with normal pressures can still go on to develop optic nerve damage and to lose vision. This is called normal (or low) tension glaucoma.