By Plano Eye Associates
Glaucoma is a group of diseases that can lead to damage of the eye’s optic nerve and result in blindness. Open-angle glaucoma, the most common form, affects about three million Americans—half of whom don’t know they have it. It has no symptoms at first but over the years it can steal your sight. With early treatment, you can often protect your eyes against serious vision loss.
Is the optic nerve affected by glaucoma?
The optic nerve is a bundle of more than one million nerve fibers. It connects the retina, the light-sensitive layer of tissue at the back of the eye, with the brain. Glaucoma damages the optic nerve by an increase in pressure within the front chamber of the eye. A clear fluid flows continuously in and out of this space and nourishes nearby tissues. Open-angle glaucoma gets its name because the angle that allows fluid to drain out of the anterior chamber is open. However, for unknown reasons, the fluid passes too slowly through the drain. As the fluid builds up, the pressure inside the eye rises. Unless the pressure at the front of the eye is controlled, it can damage the optic nerve and cause permanent vision loss.
How is glaucoma detected?
Most people think that they have glaucoma if the pressure in their eye is increased. This is not always true. High pressure puts you at risk for glaucoma. It may not mean that you have the disease. Whether or not you get glaucoma depends on the level of pressure that your optic nerve can tolerate without being damaged. This level is different for each person. That is why an eye examination is very important.
To detect glaucoma, your therapeutic optometrist will do several tests. One is a visual field test that measures your side (peripheral) vision. It helps your therapeutic optometrist find out if you have lost any of your peripheral vision, which can be a sign of glaucoma.
The pupil dilation examination provides your therapeutic optometrist with a better view of the optic nerve to check for signs of damage. Dilation is performed by placing drops into the eye to dilate (widen) the pupil. Another standard test called tonometry determines the fluid pressure inside the eye called intraocular pressure or IOP.
Who is at risk?
Although anyone can get glaucoma, some people are at a higher risk than others. They include blacks over the age of 40, everyone over the age of 60, and people with a family history of glaucoma.
Symptoms of glaucoma
At first, open-angle glaucoma has no symptoms. Vision stays normal and there is no pain. As glaucoma remains untreated, people may notice that although they see things clearly in front of them, they miss objects to the side and out of the corner of their eye. Without treatment, people with glaucoma may find that they suddenly have no side vision. It may seem as though they are looking through a tunnel. Over time, the remaining forward vision may decrease until there is no vision left.
How is glaucoma treated?
Before you begin glaucoma treatment, tell your therapeutic optometrist about any other medications you may be taking. Most doctors use topical medications for newly diagnosed patients. These drops can cause the eye to make less fluid or help drain the fluid from the eye more effectively. Some drops can cause headaches or have side effects which affect other parts of the body. They may cause stinging, burning, and redness in the eye. You will need to use the drops as long as they help to control your eye pressure. This is very important because glaucoma often has no symptoms and people may be tempted to stop or may forget to take their medicine. Although you will never be cured of glaucoma, treatment can control it.
What can you do to protect your vision?
If you are being treated for glaucoma, be sure to take your glaucoma medications every day and see your therapeutic optometrist regularly.