Open Angle Glaucoma
Glaucoma is an eye disease that can damage your optic nerve. The optic nerve supplies visual information to your brain from your eyes.
Glaucoma is usually, but not always, the result of abnormally high pressure inside your eye. Over time, the increased pressure can erode your optic nerve tissue, which may lead to vision loss or even blindness. If it’s caught early, you may be able to prevent additional vision loss.
The most common type of glaucoma is primary open-angle glaucoma. It has no signs or symptoms except gradual vision loss. For that reason, it’s important that you go to yearly comprehensive eye exams so your ophthalmologist, or eye specialist, can monitor any changes in your vision.
Acute-angle closure glaucoma, which is also known as narrow-angle glaucoma, is a medical emergency. See your doctor immediately if you experience any of the following symptoms:
- severe eye pain
- redness in your eye
- sudden vision disturbances
- seeing colored rings around lights
- sudden blurred vision
The back of your eye continuously makes a clear fluid called aqueous humor. As this fluid is made, it fills the front part of your eye. Then, it leaves your eye through channels in your cornea and iris. If these channels are blocked or partially obstructed, the natural pressure in your eye, which is called the intraocular pressure (IOP), may increase. As your IOP increases, your optic nerve may become damaged. As damage to your nerve progresses, you may begin losing sight in your eye.
What causes the pressure in your eye to increase isn’t always known. However, doctors believe one or more of these factors may play a role:
- dilating eye drops
- blocked or restricted drainage in your eye
- medications, such as corticosteroids
- poor or reduced blood flow to your optic nerve
- high or elevated blood pressure
Five major types of glaucoma exist. These are:
Open-Angle (Chronic) Glaucoma
Open-angle, or chronic, glaucoma has no signs or symptoms except gradual vision loss. This loss may be so slow that your vision can suffer irreparable damage before any other signs become apparent. According the National Eye Institute (NEI), this is the most common type of glaucoma.
Angle-Closure (Acute) Glaucoma
If the flow of your aqueous humor fluid is suddenly blocked, the rapid buildup of fluid may cause a severe, quick, and painful increase in pressure. Angle-closure glaucoma is an emergency situation. You should call your doctor immediately if you begin experiencing symptoms, such as severe pain, nausea, and blurred vision.
Children born with congenital glaucoma have a defect in the angle of their eye, which slows or prevents normal fluid drainage. Congenital glaucoma usually presents with symptoms, such as cloudy eyes, excessive tearing, or sensitivity to light. Congenital glaucoma can run in families.
Secondary glaucoma is often a side effect of injury or another eye condition, such as cataracts or eye tumors. Medicines, such as corticosteroids, may also cause this type of glaucoma. Rarely, eye surgery can cause secondary glaucoma.
Normal Tension Glaucoma
In some cases, people without increased eye pressure develop damage to their optic nerve. The cause of this isn’t known. However, extreme sensitivity or a lack of blood flow to your optic nerve may be a factor in this type of glaucoma.
According to the World Health Organization (WHO), glaucoma is the second leading cause of blindness around the world. The risk factors for glaucoma include:
People over 60 are at increased risk of glaucoma, warns the NEI, and the risk of glaucoma increases slightly with each year of age. If you’re African-American, your increase in risk begins at age 40.
African-Americans or people of African descent are significantly more likely to develop glaucoma than Caucasians. People of Asian descent are at a higher risk of angle-closure glaucoma, and people of Japanese descent have a higher risk of developing low-tension glaucoma.
Chronic eye inflammation and thin corneas can lead to increased pressure in your eyes. Physical injury or trauma to your eye, such as being hit in your eye, can also cause your eye pressure to increase.
Some types of glaucoma may run in families. If your parent or grandparent had open-angle glaucoma, you’re at an increased risk of developing the condition.
People with diabetes and those with high blood pressure and heart disease have an increased risk of developing glaucoma.
Use of Certain Medicine
Using corticosteroids for extended periods may increase your risk of developing secondary glaucoma.
To diagnose glaucoma, your ophthalmologist will want to perform a comprehensive eye examination. They’ll check for signs of deterioration, including loss of nerve tissue. They may also use one or more of the following tests and procedures:
Detailed Medical History
Your doctor will want to know what symptoms you’ve been experiencing and if you have any personal or family history of glaucoma. They’ll also ask for a general health assessment to determine if any other health conditions may be impacting your eye health, such as diabetes or high blood pressure.
This class of tests measures your eye’s internal pressure.
People with thin corneas have an increased risk of developing glaucoma. A pachymetry test can tell your doctor if your corneas are thinner than average.
This test, also known as a visual field test, can tell your doctor if glaucoma is affecting your vision by measuring your peripheral, or side, vision and your central vision.
Monitoring Your Optic Nerve
If your doctor wants to monitor for gradual changes to your optic nerve, they may take photographs of your optic nerve to conduct a side-by-side comparison over time.
The goal of glaucoma treatment is to reduce IOP to stop any additional eyesight loss. Typically, your doctor will begin treatment with prescription eye drops. If these don’t work or more advanced treatment is needed, your doctor may suggest one of the following treatments:
Several medicines designed to reduce IOP are available. These medicines are available in the form of eye drops or pills, but the drops are more common. Your doctor may prescribe one or a combination of these.
If a blocked or slow channel is causing increased IOP, your doctor may suggest surgery to make a drainage path for fluid or destroy tissues that are responsible for the increased fluid.
Treatment for angle-closure glaucoma is different. This type of glaucoma is a medical emergency and requires immediate treatment to reduce eye pressure as quickly as possible. Medicines are usually attempted first, to reverse the angle closure, but this may be unsuccessful. A laser procedure called laser peripheral iridotomy may also be performed. This procedure creates small holes in your iris to allow for increased fluid movement.
If your increased IOP can be stopped and the pressure returned to normal, vision loss can be slowed or even stopped. However, because there’s no cure for glaucoma, you’ll likely need treatment for the rest of your life to regulate your IOP. Unfortunately, vision lost as a result of glaucoma cannot be restored.
Glaucoma can’t be prevented, but it’s still important to catch it early so you can begin treatment that will help prevent it from getting worse. The best way to catch any type of glaucoma early is to have an annual preventive eye care appointment. Make an appointment with an ophthalmologist. Simple tests performed during these routine eye checks may be able to detect damage from glaucoma before it advances and begins causing vision loss.
Written by: Kimberly Holland
Medically reviewed on Jan 29, 2016 by George Krucik, MD