Glaucoma 201: Side Vision Loss

Why is Glaucoma such a devastating disease? Well, two reasons. The first, of course, is that it robs you of your vision. The second is that this "thief" steals your vision slowly and painlessly, and you may not even know you have glaucoma until it's too late!

Your peripheral, or side vision is the first part of your vision to be lost in glaucoma. This is one of the reasons it's so hard to know that you have the disease, because your central vision, the vision you read and drive with, is preserved until very late in the disease.

We measure your side vision with a test called a "Visual Field" or Perimetry test. Modern testing is computerized. You place your chin on a chin rest and look into a dim, white bowl. When you see a light come into view you press a button. The readout looks like this: 

   

In the early stages you might only lose a very small portion of your vision.

In very late stages much of your side vision is gone; it can be like looking through a tunnel.

Don't let glaucoma steal your vision!                  

Family History and Glaucoma Screening

You've seen them at the mall or at a health fair, the Glaucoma screening booths. The dreaded "air puff" to check your eye pressure to see if you might have Glaucoma. There are actually lots of different ways to screen for Glaucoma risk, and this is a very active area of research for eye doctors. What's the best way to screen for Glaucoma?

First, a couple of thoughts on what a screening test should do and not do. When you have a disease that is sneaky, like Glaucoma, and it doesn't have any outward symptoms to let you know it is there, sometimes it makes sense to have some kind of test that will let you know that you DO either have the disease or at a high risk to get it. Glaucoma is like this; there are no symptoms in early Glaucoma, and by the time your vision is affected to a point where you know something is wrong it's too late.

A screening test should be easy to do. It should be relatively inexpensive. It shouldn't hurt! The test should be able to identify pretty much anyone who MIGHT have the disease, and it definitely shouldn't miss anyone who actually HAS the disease (a false negative result). In a perfect world the screening test would not falsely find that healthy people have a the test (a false positive result), but we usually accept less accuracy here because we don't want to miss anyone who is at risk.

So how about Glaucoma screening? Well, high pressure is a risk factor for Glaucoma, so identifying people with high pressure will get them referred to an eye doctor which is what we want. There is something called a "nerve fiber analyzer" which will also do the same thing but with a little higher accuracy. Both of these screenings suffer from the expense of the equipment and the need to have trained people doing the test.

It turns out that for Glaucoma there is a really effective screening test that identifies one of the top two risk factors for developing the disease and losing vision: ask someone if they have a family member who has or had Glaucoma! Research has shown that a family history of Glaucoma, especially vision loss from Glaucoma, is the most important risk factor, and that if you DO have a family history you should have a complete Glaucoma examination at the eye doctor's office. Like Skyvision in Cleveland!

Do you have Glaucoma? Tell all of your relatives to have a complete eye exam.

Glaucoma Awareness Month

January is Glaucoma Awareness month in the United States. Glaucoma is damage to the optic nerve, the part of the eye that brings vision information from the eye to the brain. It is usually, but not always associated with high eye pressure. The normal eye pressure is 11-21. Some people who have very high pressure will never develop Glaucoma, but unfortunately some people with "normal" pressure will develop all of the vision problems associated with the disease.

The most common type of Glaucoma, Primary Open Angle Glaucoma, causes a slow, painless loss of side vision before any central vision problems come up. Vision loss is permanent, so the name of the game is prevention!

The most common risk factor for the development of Glaucoma is a family history, especially if your family member had severe vision loss from Glaucoma or developed it a very early age. Not everyone in a family will get Glaucoma, but the risk could be as high as 30%! Make sure you know your family eye history.

Every person should have a complete eye exam that includes a dilated pupil examination of the optic nerve. If there is high pressure or any question of abnormalities you may be asked to under further testing. Be aware of Glaucoma, this month and every month!