The most common and basic educational problem I face as a glaucoma specialist is to make the distinction for the patient between intraocular “pressure,” and the disease of glaucoma itself.
Forty or so years ago if a patient had an intraocular pressure above “normal” they were considered to have glaucoma, and conversely, if the pressure was “normal” then the patient was considered not to have glaucoma. “Normal” was generally defined as pressures up to about 22 or 24 millimeters of mercury. The goal of treatment was to bring the pressure to a “normal” range.
Since that time, we have discovered people with intraocular pressures in the 20’s or closer to 30 who do not have glaucoma. Many of these people may never develop glaucoma. At the other extreme, there are patients whose intraocular pressures are never above the mid teens, and these people have significant glaucoma with a high risk of losing the remainder of their vision.
Glaucoma is actually a disease of the optic nerve which gradually causes the optic nerve to deteriorate and the vision to slowly decline. Notice that this definition of glaucoma doesn’t mention “intraocular pressure”. There are other risk factors for glaucoma. These factors include race, high myopia (nearsightedness), family history of blindness from glaucoma,and age. Lowering the intraocular pressure is the major emphasis of treatment because it is the only manageable risk factor. Therefore, it is easy to misinterpret that “pressure” is the disease glaucoma. A better way to think of the intraocular pressure is as a risk factor for causing optic nerve damage in the disease glaucoma.
I set a pressure goal for each patient I see. For some patients, the pressure needs to be lowered to the mid or upper twenties. For other patients, the pressure must be below ten. As you can see, there is a wide discrepancy in the pressure goal I strive for. When you see me next, ask what “goal” I am trying to achieve for you so you will have a context to interpret your pressure levels,
The more you master this particular concept about your disease, the more you will understand the treatment for your glaucoma.