Glaucoma

What exactly is glaucoma?

Glaucoma is a condition in which the eye's intraocular pressure (IOP) is too high. This means that your eye has too much >aqueous humor in it, either because it produced too much, or because it's not draining properly. Other symptoms are optic nerve damage and vision loss.

What's the difference between glaucoma and ocular hypertension?

Ocular hypertension is another term for high IOP; the pressure is not high enough to cause optic nerve damage and vision loss.

Why does my eye doctor want to do more than one kind of glaucoma test?

The "puff test" that most people are familiar with measures IOP. Another way doctors may measure it is by pressing an instrument called an applanation tonometer against your eye to determine how much resistance there is.

Your doctor may also want to check for optic nerve damage by dilating your eyes, or to check for vision loss with a visual field test.

What are the signs and symptoms of glaucoma?

There are usually no signs that you're developing glaucoma until vision loss occurs, which is why it's so important to have regular eye exams. Your eye doctor can diagnose and treat high IOP before it progresses to optic nerve damage and vision loss.

What are the Different Types of Glaucoma?

There are many types of glaucoma. Often, the cause of high pressure in the eye can help tell the type of glaucoma and the best treatment for it. The most common types include:

Chronic (Open Angle) Glaucoma
This is the most common type. In open angle glaucoma, aqueous fluid drains too slowly and pressure inside the eye builds up. It usually results from aging of the drainage channel, which doesn't work as well over time. However, younger people can also get this type of glaucoma.

Normal Tension Glaucoma
This is a form of open angle glaucoma not related to high pressure. People with normal tension glaucoma may be unusually sensitive to normal levels of pressure. Reduced blood supply to the optic nerve may also play a role in normal tension glaucoma.

Acute (Angle Closure) Glaucoma
Less than 10 percent of Caucasians or African-Americans have this form, but for those of Asian and Native American descent, the risks are as high as for open angle glaucoma. Hispanics are midway between these groups. It causes a sudden rise in pressure, requiring immediate, emergency medical care. The signs are usually serious and may include blurred vision, severe headaches, eye pain, nausea, vomiting or seeing rainbow-like halos around lights. Occasionally, the condition may be without symptoms; similar to open angle.

Secondary Glaucoma
Another 10 percent of glaucoma cases come from certain diseases and conditions that damage the eye's drainage system. These include diabetes, leukemia, sickle-cell anemia, some forms of arthritis, cataracts, eye injuries or inflammation of the eye, steroid drug use and growth of unhealthy blood vessels.

Post-Surgical Glaucoma
Some surgeries, such as retinal reattachments, increase the chance of getting glaucoma.