Glaucoma is a group of eye disorders in which the optic nerves connecting the eyes and the brain are progressively damaged. This damage can lead to reduction in side (peripheral) vision and eventual blindness. Other signs and symptoms may include bulging eyes, excessive tearing, and abnormal sensitivity to light (photophobia). The term "early-onset glaucoma" may be used when the disorder appears before the age of 40.

In most people with glaucoma, the damage to the optic nerves is caused by increased pressure within the eyes (intraocular pressure). Intraocular pressure depends on a balance between fluid entering and leaving the eyes.

Usually glaucoma develops in older adults, in whom the risk of developing the disorder may be affected by a variety of medical conditions including high blood pressure (hypertension) and diabetes mellitus, as well as family history. The risk of early-onset glaucoma depends mainly on heredity.

Structural abnormalities that impede fluid drainage in the eye increase ocular pressure. These abnormalities may be present at birth and usually become apparent during the first year of life. Such structural abnormalities may be part of a genetic disorder that affects many body systems, called a syndrome. If glaucoma appears before the age of 3 without other associated abnormalities, it is called primary congenital glaucoma.

Other individuals experience early onset of primary open-angle glaucoma, the most common adult form of glaucoma. If primary open-angle glaucoma develops during childhood or early adulthood, it is called juvenile open-angle glaucoma.

Approximately 10 percent to 33 percent of people with juvenile open-angle glaucoma have variants (also known as mutations) in the MYOC gene. MYOC gene variants have also been detected in some people with primary congenital glaucoma. The MYOC gene provides instructions for producing a protein called myocilin. Myocilin is found in certain structures of the eye, called the trabecular meshwork and the ciliary body, that regulate the intraocular pressure.

Researchers believe that myocilin functions together with other proteins in the eye as part of the extracellular matrix, which is an intricate lattice that forms in the space between cells and provides structural support. Variants may alter the protein in such a way that the protein is not part of the extracellular matrix. Defective myocilin that does not get incorporated in the extracellular matrix remains inside the cell. The defective protein may damage the cell, causing insufficient flow of fluid from the eye, resulting in increased intraocular pressure and causing the signs and symptoms of early-onset glaucoma.

Between 20 percent and 40 percent of people with primary congenital glaucoma have variants in the CYP1B1 gene. CYP1B1 gene variants have also been detected in some people with juvenile open-angle glaucoma. The CYP1B1 gene provides instructions for producing a form of the cytochrome P450 protein. Like myocilin, this protein is found in the trabecular meshwork, ciliary body, and other structures of the eye.

It is not well understood how defects in the CYP1B1 protein cause signs and symptoms of glaucoma. Recent studies suggest that the defects may interfere with the early development of the trabecular meshwork, the tissue that regulates the secretion of fluid inside the eye.

Unknown variants in other genes may also be involved in early-onset glaucoma.

Normal Function

The MYOC gene provides instructions for producing a protein called myocilin. Myocilin is found in certain structures of the eye, called the trabecular meshwork and the ciliary body, that regulate the pressure within the eye (intraocular pressure). Myocilin's function is not well understood, but it may help to control the intraocular pressure through its action in the muscle tissue of the ciliary body.

Researchers believe that myocilin functions together with other proteins in the eye as part of the extracellular matrix, which is an intricate lattice that forms in the space between cells and provides structural support. Myocilin may interact with a number of other proteins that also function in the extracellular matrix.

Health Conditions Related to Genetic Changes

Early-onset glaucoma

Approximately 10 percent to 33 percent of people with juvenile open-angle glaucoma have variants (also called mutations) in the MYOC gene. People with this condition experience increased pressure within the eye before the age of 40. MYOC gene variants have also been detected in some people with primary congenital glaucoma. More than 100 MYOC gene variants have been identified.

Variants in the MYOC gene may alter the myocilin protein so that its interactions with other proteins are impeded. Defective myocilin that does not get incorporated in the extracellular matrix remains inside the cell. The defective protein may damage the cell, causing insufficient flow or fluid from the eye, resulting in increased intraocular pressure and causing the signs and symptoms of early-onset glaucoma.

Other disorders

A small percentage (3 to 5 percent) of individuals with late-onset primary open-angle glaucoma (POAG), the most common adult form of glaucoma, have variants in the MYOC gene.

Other Names for This Gene

• GLC1A
• GPOA
• JOAG
• JOAG1
• MYOC_HUMAN
• myocilin, trabecular meshwork inducible glucocorticoid response
• TIGR
• trabecular meshwork-induced glucocorticoid response protein

Genomic Location

Normal Function

The CYP1B1 gene provides instructions for producing an enzyme that is a member of the cytochrome P450 family of enzymes. These enzymes are involved in many processes in the body, such as assisting with reactions that break down drugs and produce certain fats (lipids). The CYP1B1 enzyme participates in biochemical reactions in which an oxygen atom is added to other molecules.

The CYP1B1 enzyme is active in many tissues, including structures of the eye. The function of the CYP1B1 enzyme in the development of the eye is unclear, but it may play a role in forming structures at the front of the eye and may also be involved in a process that regulates the secretion of fluid inside the eye.

Health Conditions Related to Genetic Changes

Early-onset glaucoma

More than 140 CYP1B1 gene variants (also called mutations) have been identified to cause early-onset glaucoma. People with this condition experience increased pressure within the eye before the age of 40. This pressure causes damage to the optic nerves connecting the eyes and the brain. Between 20 percent and 40 percent of people with glaucoma before the age of 3 (primary congenital glaucoma) have variants in the CYP1B1 gene. The variants that cause early-onset glaucoma may result in an enzyme that is unstable or the wrong shape.

It is not well understood how changes in the CYP1B1 enzyme cause signs and symptoms of glaucoma. Recent studies suggest that the defects may interfere with the early development of the trabecular meshwork, which is a network of mesh-like canals that helps drain excess fluid from the eye. If fluid cannot be drained, pressure inside the eye may increase, which is characteristic of glaucoma.

Peters anomaly

A few variants in the CYP1B1 gene have been found to cause Peters anomaly. This condition is characterized by abnormal development of certain structures at the front of the eye and clouding of the clear front surface of the eye (cornea). The variants that cause Peters anomaly likely impair the normal function of the CYP1B1 enzyme or disrupt enzyme production. As a result, there is a shortage (deficiency) of normal enzyme. A lack of the CYP1B1 enzyme likely disrupts normal development of the eye, although it is unclear exactly how this deficiency leads to the features of Peters anomaly.

Other Names for This Gene

• aryl hydrocarbon hydroxylase
• CP1B
• CP1B1_HUMAN
• cytochrome P450, family 1, subfamily B, polypeptide 1
• cytochrome P450, subfamily I (dioxin-inducible), polypeptide 1 (glaucoma 3, primary infantile)
• flavoprotein-linked monooxygenase
• GLC3A
• microsomal monooxygenase
• xenobiotic monooxygenase

Genomic Location

Early-onset glaucoma can have different inheritance patterns. Primary congenital glaucoma is usually inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have variants. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but do not show signs and symptoms of the condition.

Juvenile open-angle glaucoma is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some families, primary congenital glaucoma may also be inherited in an autosomal dominant pattern.

Glaucoma is a group of diseases that damage the eye’s optic nerve, which carries visual signals from the eye to the brain. If left untreated, glaucoma can lead to vision loss or blindness. But many people with early-stage glaucoma have no symptoms. By the time they’re diagnosed, they may have already noticed changes to their side, or peripheral, vision.

“Studies show that at least half of all people with glaucoma don’t know they have this potentially blinding eye disease,” says Dr. Paul Sieving, director of NIH’s National Eye Institute. “The good news is that glaucoma can be detected in its early stages through a comprehensive dilated eye exam.”

With early detection, glaucoma can be controlled through medications or surgery. Early treatment can protect the eyes against serious vision loss.

Anyone can get glaucoma, but some people are at increased risk. At-risk groups include African Americans ages 40 and older; everyone over age 60, especially Hispanics/Latinos; and people who have a family history of the disease.

If you’re at increased risk, be sure to get a comprehensive dilated eye exam every 1 to 2 years. And encourage family members to do the same.

Doctors use a few different types of treatment for glaucoma, including medicines (usually eye drops), laser treatment, and surgery.

If you have glaucoma, it’s important to start treatment right away. While it won’t undo any damage to your vision, treatment can stop it from getting worse.

Medicines. Prescription eye drops are the most common treatment. They lower the pressure in your eye and prevent damage to your optic nerve.

Laser treatment. To lower pressure in your eye, doctors can use lasers to help the fluid drain out of your eye. It’s a simple procedure that your doctor can do in the office.

Surgery. If medicines and laser treatment don’t work, your doctor might suggest surgery. There are several different types of surgery that can help the fluid drain out of your eye.

Talk over your options with your doctor. While glaucoma is a serious disease, treatment works well. Remember these tips:

• If your doctor prescribes medicine, be sure to take it every day

• Tell your doctor if your treatment causes side effects

• See your doctor for regular check-ups

• If you’re having trouble with everyday activities because of your vision loss, ask your doctor about low vision services or devices that could help

• Encourage family members to get checked for glaucoma, since it can run in families

Glaucoma is a group of eye diseases that can cause vision loss and blindness by damaging the nerve in the back of your eye called the optic nerve.

The most common treatment for glaucoma is prescription eye drops. They work by lowering the pressure in your eye and preventing damage to your optic nerve. These eye drops won’t cure glaucoma or reverse vision loss, but they can keep glaucoma from getting worse.

If your doctor prescribes eye drops for glaucoma, you’ll need to use them every day. Depending on the type of medicine, you may need to use them once, twice, or up to 4 times a day.

Stick with it

Some people with glaucoma stop using their eye drops after a while. They may forget, get out of the habit, or think the medicine isn’t helping.

But remember, glaucoma eye drops won’t make you feel different or improve your vision. They prevent your vision from getting worse. If you don’t use them as prescribed, you could lose your vision.

What types of eye drops can help glaucoma?

There are many medicines available to treat glaucoma. Before you start taking glaucoma medicines, tell your doctor about other medicines, supplements, or vitamins you take. Eye drops for glaucoma may affect how those other medicines work.

Some types of eye drops work by helping fluid drain from your eye, which lowers eye pressure. Examples include:

• Prostaglandins, like latanoprost (Xalatan), travoprost (Travatan Z), tafluprost (Zioptan), and bimatoprost (Lumigan)

• Rho kinase inhibitor, like netarsudil (Rhopressa)

• Nitric oxides, like latanoprostene bunod (Vyzulta)

• Miotic or cholinergic agents, like pilocarpine (Isopto Carpine)

Other types of eye drops work by lowering the amount of fluid your eye makes. Examples include:

• Alpha-adrenergic agonists, like apraclonidine (Iopidine) and brimonidine (Alphagan P, Qoliana)

• Beta blockers, like timolol (Betimol, Istalol, Timoptic) and betaxolol (Betoptic)

• Carbonic anhydrase inhibitors, like dorzolamide (Trusopt) and brinzolamide (Azopt)

What are the side effects?

Most people don’t have problems with glaucoma medicines. But there’s a small chance that you could develop:

• Stinging, itching, burning, and redness in your eye

• Blurry vision

• Changes in your eye color or the skin around your eye

• Headaches

• Dry mouth

• Changes in your energy level, heartbeat, or breathing

The specific side effects depend on which medicine you’re taking. If you notice any side effects, talk to your doctor. You may be able to take a different dose (amount) or a different medicine.

How long will I need to use glaucoma eye drops?

As long as the medicine is working, your doctor will probably want you to keep using it every day.

If eye drops don’t lower the pressure in your eye enough, your doctor may recommend prescription pills as well — but this is uncommon.

Your doctor may also suggest other treatment options, like surgery.

Laser treatment can help treat some types of glaucoma. It’s a procedure that your eye doctor can do in the office. It works by helping the fluid in your eye drain, which can help lower the pressure inside your eye. Ask your eye doctor if laser treatment is right for you.

Do I need laser treatment for my glaucoma?

A laser treatment called trabeculoplasty (tra-BECK-you-low-plas-tee) is used to treat open-angle glaucoma. There are other types of laser treatment that can treat other types of glaucoma.

Ask your eye doctor about all your glaucoma treatment options, including medicines, laser treatment, and surgery. You and your doctor can work together to make a treatment plan that’s right for you.

What happens during laser treatment for glaucoma?

When you get laser treatment, your doctor will:

• Put drops in your eye to make it numb
• Aim a laser (a strong beam of light) into your eye using a special lens
• Use the laser to try to help fluid drain from your eye

You may see flashes of bright green or red light during the treatment. Most people feel little or no pain or discomfort during the treatment.

If you have glaucoma in both eyes, your doctor may treat both eyes on the same day — or they may treat 1 eye and schedule treatment for your other eye a few days or a few weeks later.

Are there any side effects?

Laser treatment can cause side effects, just like any procedure.

You may have some swelling or soreness. Sometimes the laser can scratch the cornea (the clear front layer of the eye) or make the cornea very dry. This can be painful, but the pain usually goes away quickly as the cornea heals. Your doctor can give you eye drops to help.

How long does it take to recover?

Most people can go back to their normal daily activities the day after their laser treatment.

Right after the treatment, your eye may be irritated and your vision might be blurry, so you’ll need someone to give you a ride home from the doctor’s office.

Will I need more treatment?

Laser treatment works very well for most people, but it doesn’t work for everyone. You’ll need to wait 4 to 6 weeks to find out if the treatment worked.

Most people will need to keep taking glaucoma medicine even after laser treatment. You’ll also need a few follow-up visits so your doctor can check your eye pressure.

Because the treatment wears off over time, some people may need to get laser treatment more than once. Your doctor may also suggest other treatment, like glaucoma surgery.

Glaucoma is a group of eye diseases that can cause vision loss and blindness by damaging the nerve in the back of your eye called the optic nerve.

If glaucoma medicines and laser treatment haven’t helped to treat your glaucoma, your doctor may recommend surgery. Surgery can’t cure glaucoma or undo vision loss, but it can help protect your vision and stop it from getting worse.

There are a few different types of surgery for glaucoma that can help lower the pressure in your eye:

• Trabeculectomy (tra-BECK-yoo-LECK-toh-mee)

• Glaucoma implant surgery

• Minimally invasive glaucoma surgery (MIGS)

If you need glaucoma surgery in both eyes, your doctor will only do surgery on 1 eye at a time.

What is trabeculectomy?

This type of surgery is usually used to treat open-angle glaucoma. It’s done in a hospital and usually takes less than an hour.

The surgeon will create a tiny opening in the top of your eye. The opening will be under your eyelid, where no one will see it. This opening allows extra fluid in your eye to drain away, lowering pressure in your eye.

Usually, you’ll be awake during this surgery — but you’ll get numbing medicine and medicine to help you relax. You can usually go home the same day, but you’ll need someone to drive you home.

What is glaucoma implant surgery?

This type of surgery is used to treat several types of glaucoma, including congenital glaucoma, neovascular glaucoma, and glaucoma caused by an injury. It’s done in a hospital and usually takes 1 to 2 hours.

In this operation, the surgeon implants a tiny tube, or shunt, onto the white part of your eye. The tube helps extra fluid drain out of your eye, lowering your eye pressure.

Usually, you’ll be awake during this surgery — but you’ll get numbing medicine and medicine to help you relax. You can usually go home the same day, but you’ll need someone to drive you home.

What is minimally invasive glaucoma surgery (MIGS)?

If you have mild glaucoma, your doctor may recommend a new approach called minimally invasive glaucoma surgery (MIGS). This also lowers eye pressure, but it has fewer risks and side effects and helps you recover faster.

There are different types of MIGS, so ask your eye doctor about whether MIGS may be an option for you.

What happens after surgery?

Your doctor will prescribe eye drops to help prevent swelling and infections, and you’ll need to use them for several weeks. These eye drops are different from other glaucoma eye drops you may already use.

While you recover, you may need to avoid some activities for 2 to 4 weeks, like lifting anything heavy. You’ll also need check-ups with your doctor to make sure your eye is healing well.

Will I need surgery again?

For some people, the benefits of surgery last a long time. For others, the opening in the eye begins to close up and they need surgery again. You’ll need regular check-ups with your doctor to test your eye pressure. That way, your doctor will be able to act fast if you need more treatment.

Research shows that trabeculectomy can lower eye pressure in about 7 out of 10 people. It may work best in people who haven’t had an eye injury or another eye surgery.

What are the side effects of surgery for glaucoma?

Glaucoma surgery can have side effects, just like any operation. For example, your eye may be swollen and sore for a while.

Other possible risks of glaucoma surgery include:

• Cataract

• Problems with the cornea (the clear front layer of your eye)

• Eye pressure that’s too low

• Vision loss

Talk over the pros and cons of surgery with your doctor. Together, you can make a treatment plan that’s right for you.

If you or a loved one has been diagnosed with glaucoma, you may have questions about what this means.

There's no cure for glaucoma, but here's the good news - it can be treated. And starting treatment early is the best way to stop the damage and protect your vision.

Talk to your eye doctor about your symptoms and treatment options. You can use this guide to get the conversation going.

Questions for your doctor

Visiting the doctor can be stressful, especially when you're dealing with a new diagnosis. It helps to have questions written down ahead of time.

• What type of glaucoma do I have?
• How often do I need to get a checkup for my glaucoma?
• What are my treatment options?
• What will happen if I don't get treated for my glaucoma?
• How will I know if my treatment is working?
• What are the possible dangers or side effects from treatment?
• Does glaucoma put me at risk for other eye diseases?
• What can I expect for my vision - now and in the future?
• Are there any activities I should avoid?

Primary congenital glaucoma affects approximately 1 in 10,000 people. Its frequency is higher in the Middle East. Juvenile open-angle glaucoma affects about 1 in 50,000 people. Primary open-angle glaucoma is much more common after the age of 40, affecting about 1 to 2 percent of the population worldwide.