What Is Glaucoma?

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What is glaucoma?

When I'm asked that question, I'm tempted to go into a long explanation that would probably put people to sleep. I'll try not to do that, but I will say that glaucoma is an eye disease that causes a loss of vision when the pressure level in the eye does not allow the nerves of the eye to get the flow of blood and other growth factors they need to stay healthy. The nerves will then slowly atrophy and die. Glaucoma nerve damage can occur at any level of pressure, but the higher the pressure, the more likely and the more quickly nerve damage can occur.

An analogy that I like to use compares the nerves of the eye to a garden. A hose goes to the garden and brings water to the plants. If someone puts pressure on the hose, slowing the flow or cutting off the water, the plants wilt and eventually die.

In the eye, the nerves depend on a flow of blood and nutrients. If the pressure of the eye gets to a level that slows or stops the flow of these nutrients, the nerves will atrophy and possibly die, one by one.

Every eye needs to have some pressure, just like a basketball or tire needs to have some pressure inside. It's when this pressure becomes higher than the nerves can tolerate that we say a person has glaucoma.

How do we diagnose and treat glaucoma? First, we look at risk factors. These include family history, older age, African descent, diabetes, near-sightedness, hypertension, steroid use, and trauma.

A complete eye exam, including a measurement of the eye pressure, is performed. If glaucoma is suspected, further tests are done to look for changes that indicate the presence of nerve damage. These are noninvasive and painless tests like nerve scans and visual fields, along with examination of the part of the eye where the fluid of the eye drains, called the “angle,” to determine whether the drain is open, narrow or closed completely. If the angle is very narrow or closed, then the glaucoma is considered to be of the “narrow angle” type versus the more common “open angle” type. Both forms of glaucoma have no symptoms early on and can be diagnosed only during an eye examination.

Narrow angle glaucoma is usually treated with a simple laser procedure that effectively enlarges the drainage angle, restoring normal fluid flow out of the eye and preventing “angle closure,” which is a sudden medical emergency that requires immediate treatment to lower the eye pressure, which will be so high that nerve damage can occur quickly. The normal range of eye pressure is about 10 to 21, with an average of about 16. In cases of angle closure, the pressure may go as high as 70 or 80.

If it is believed that the patient does have glaucoma, the treatment is always going to be to lower the eye pressure. This is done through eye drop medications, lasers, and perhaps surgery if the other methods are not successful at slowing the disease progression.

So, if you have not had an eye exam, and especially if you have any risk factors for glaucoma (or any eye disease for that matter), schedule a complete eye examination soon.

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