Glaucoma Tests

Glaucoma tests are eye tests that help diagnose glaucoma. Glaucoma is a group of eye diseases that can damage a nerve in the back of your eye called the optic nerve. This nerve connects your eyes to your brain, allowing you to see.

Damage to the optic nerve can cause vision loss and blindness. Glaucoma tests can help find the disease before you know you have it, so you can start treatment to protect your eyes against serious vision loss. Researchers aren't sure exactly what causes the most common types of glaucoma.

But having high fluid pressure in one or both eyes increases your risk for the disease. Your eyes are always making fluid that nourishes the tissues inside the eye. The fluid leaves your eyes through a drainage system with openings in the space where your iris (the colored part of your eyes) and your cornea (the clear front layer of your eyes) meet.

The pressure inside of each eyes stays in a healthy range when there's a balance between how much fluid your eye makes and how much drains out of your eye. If the drainage system becomes clogged or blocked, fluid can't drain at a normal rate. If your eye makes new fluid faster than it can drain, the fluid backs up, which increases the pressure in your eye.

The high pressure may damage the optic nerve and lead to serious vision problems. There are several types of glaucoma. The main types are: Open-angle glaucoma, also called primary open-angle glaucoma.

This is the most common type. It's called 'open' because the canals that lead to your eye's drainage system are open. But deeper inside the drainage system, clogs develop.

These clogs slow the fluid drainage. Open-angle glaucoma tends to affect both eyes. In the early stages, Most people don't have any symptoms or vision changes.

But without treatment, peripheral (side) vision is usually lost first. ; Closed-angle glaucoma, also called angle-closure or narrow-angle glaucoma. In this uncommon type of glaucoma, the canals that drain fluid from your eye are 'closed' because your iris covers them. This condition usually affects one eye at a time.

There are two main types: Acute closed-angle glaucoma is a medical emergency. No fluid can drain out of your eye, so eye pressure increases suddenly. This causes eye pain, blurry vision, and other symptoms.

Without prompt treatment, it can cause blindness in a few days.; Chronic closed-angle glaucoma develops slowly over time. You may not have any symptoms. Or you may have symptoms such as eye discomfort, blurry vision, redness, or headaches.

The symptoms often get better with sleep. Without treatment, vision loss develops slowly.; ;

Why this test is done

Anyone can get glaucoma. To protect your vision, it's important to be tested for glaucoma before symptoms start. When to start testing and how often to get tested will depend on your risk for glaucoma.

Your risk for glaucoma may be high if you:

• Are over age 60. Glaucoma is much more common in older people. The risk is especially high if you are an older Hispanic/Latino American.
• Are an African American over age 40. Glaucoma is the leading cause of blindness in African Americans.
• Are an Asian American. Asian Americans have a higher risk for getting a type of open-angle glaucoma called normal-pressure or normal-tension glaucoma. With this condition, optic nerve damage begins when eye pressure is normal or a little higher than normal. But treatments that lower eye pressure often help.
• Have a family history of glaucoma. You can inherit certain types of glaucoma from your parents.
• Have certain medical conditions. They include diabetes and high blood pressure.

If your risk of glaucoma is high, ask your health care provider or eye care specialist when you should start getting tested and how often you need to have your eyes checked. Getting an eye exam with glaucoma testing by age 40 can help catch glaucoma and other eye diseases early.

If you have symptoms of acute closed-angle glaucoma, you need to be tested for glaucoma right away to prevent blindness. Symptoms may start suddenly and be severe. They include:

• Blurry vision
• Severe eye pain
• Red eyes
• Colored halos around lights
• Nausea or vomiting
• Headache

If you have glaucoma, you may need regular testing to monitor your condition and check whether your treatment is working.

How to prepare

If you wear glasses or contact lenses, bring them with you. Bring sunglasses to wear after your exam in case your eyes are sensitive to light. Also, plan to have someone take you home because your vision may be blurry.