Q: I have always had normal eye pressures, but my new eye doctor is telling me I am developing glaucoma. This is confusing to me.
A: I believe the vast majority of people, just like you, think that measuring your eye pressure is “the” test for glaucoma. It is not.
Glaucoma is a complex eye disease that slowly, and worst of all….painlessly, will cause you to lose your eyesight. We generally recommend a complete medical eye exam annually for adults largely because of this disease. Glaucoma is very dangerous, but gives your absolutely NO symptoms in most cases. Rare cases that involve exceptionally high pressures can cause headaches, blurring vision and even nausea. This is very rare.
In fact, glaucoma is now considered a “vascular” disease of the eye: meaning the optic nerve is not getting adequate blood flow. That slowly but surely kills more and more optic nerve cells, which means slowly losing your sight. Some studies now indicate that this ”normal” pressure glaucoma may be the most common type….not the high pressure type.
Diagnosing glaucoma is not dependent on one test. In fact, we use at least three tests to decide if you have glaucoma. First, we do measure your intraocular eye pressure ( but not with the “air puff” test anymore ), second, we do optical scanning of the optic nerve and retina to detect any tissue thinning, and third we analyze your visual field. The scanning will find areas where nerve tissue is abnormally thin, indicating higher risk of nerve damage. Visual field testing lets us evaluate if your optic nerve is functioning normally or already is starting to lose some early area of sight. It is the clinical judgement of all these, and sometimes more, that leads us to believe you have glaucoma in some stage or not.
Good news: early detection and treatment with medications or lasers can usually slow or stop progression. Our goal is to find glaucoma so early that you never have any noticeable loss of vision during your life! Caution: highest risk patients are those with glaucoma in the family. Certain ethnic and racial factors can also increase your risk. Smoking and cardiovascular disease will increase the risk for anyone. Again, control is very effective to prevent loss of sight.