Your optic nerve sends visual information from your eye to your brain. Glaucoma can damage the optic nerve, leading to vision loss that may increase without treatment.

doctor pointing at model of the anatomy of the human eyeShare on Pinterest
AegeanBlue/Getty Images

Glaucoma is a neurodegenerative disease that can damage the optic nerve at the back of your eye. It may affect one or both of your eyes. It isn’t currently curable, but treatment may help prevent further vision loss.

About 90% of people with glaucoma have open-angle glaucoma. It gradually prevents your eye from draining fluid, causing increased eye pressure that can eventually damage optic nerve tissue.

Other types of glaucoma include:

  • normal-tension glaucoma, which can occur with regular eye pressure
  • closed-angle glaucoma, a medical emergency where your iris stops fluids from draining from the front of your eye, causing possible blindness within just a few days
  • congenital glaucoma, a rare form where the fluids in a baby’s eyes don’t drain normally

If glaucoma is left untreated, damage to the optic nerve may lead to vision loss or blindness.

Your optic nerve contains about 1 million nerve fibers that enable you to see by sending visual information to your brain through the optic disc at the back of your eye.

In the center of the optic disc is a small dip called a cup. Increased pressure in your eye or decreased blood flow to your optic nerve due to glaucoma may destroy the nerve fibers, enlarging the cup. This is called optic nerve cupping.

In the late stages of glaucoma, cupping can become severe as vision loss occurs. After damaging your optic nerve, you cannot restore the vision you have lost.

Most people with open-angle glaucoma, the most common type of glaucoma, don‘t have any symptoms until the very late stages of the disease.

According to the Centers for Disease Control and Prevention (CDC), half of all people with open-angle glaucoma may be unaware they have it. In the late stages, you may notice loss of peripheral vision or tunnel vision and, eventually, complete vision loss.

Normal-tension glaucoma may cause blind spots and optic nerve damage.

With closed-angle glaucoma, early symptoms may include:

Early indications of glaucoma

Glaucoma often has no early symptoms. As the disease progresses, you may experience a gradual loss of your peripheral (side) vision, particularly your vision close to your nose.

Was this helpful?

An ophthalmologist will diagnose optic nerve damage by performing a complete eye exam, which may include some of the following tests:

  • Tonometry: The doctor measures the pressure in your eye by gently pressing a probe against your eye’s surface or using an instrument that painlessly blows a puff of air at your cornea.
  • Ophthalmoscopy: After dilating your pupils with eye drops, the doctor uses a lighted magnifying lens to examine your optic nerve and the back of your eye.
  • Perimetry: This visual field test checks your peripheral vision.
  • Gonioscopy: After numbing your eyes with eye drops, the doctor places a mirrored contact lens on your eye that shows whether the angle between your iris and cornea is open and wide, which may indicate open-angle glaucoma.
  • Pachymetry: This painless test measures the thickness of your cornea using a probe gently placed on the surface of your eye.

Diagnosing glaucoma can be challenging because of its many variables, as well as other eye conditions that are similar to the disease.

To determine what is causing your symptoms, an ophthalmologist may perform a differential diagnosis. This means that based on your symptoms, medical history, and eye exam results, the doctor will list the possible diseases or conditions that could be causing your symptoms.

Depending on the differential diagnosis, the doctor may perform additional exams to rule out glaucoma and make a final diagnosis.

What can cause optic nerve cupping without glaucoma?

Optic nerve cupping may also occur in people who don’t have glaucoma or optic nerve damage. However, the enlarged cup is usually not as large as that of someone with glaucoma.

Some of the other conditions that may cause optic nerve cupping include:

  • optic neuritis: inflammation of your optic nerve
  • compressive optic neuropathy: compression of the optic nerve, usually by a tumor
  • ischemic optic neuropathy: prevents blood from flowing to your optic nerve
  • hereditary optic neuropathy: optic nerve damage caused by genetic anomalies
Was this helpful?

Although damage to the optic nerve is permanent and irreversible, treatments may help prevent more vision loss.

Treatments for optic nerve damage may include the following:

  • Eye drops: Doctors most often prescribe eye drops to lower pressure by reducing the fluid produced by your eye. You’ll need to use them every day.
  • Laser surgery: Usually performed in the doctor’s office, laser surgery can also help fluid drain from your eye.
  • Surgery: A doctor may perform a trabeculectomy, creating a tiny flap under your eyelid to help drain fluid.

The following are answers to some frequently asked questions about how glaucoma affects your optic nerve.

How long does it take for glaucoma to damage the optic nerve?

The uncommon closed-angle glaucoma can damage the optic nerve and cause blindness within a few hours or days if left untreated.

With the more common open-angle glaucoma, it may take many years for damage to the optic nerve to result in vision loss.

What percentage of people with glaucoma go blind?

Without treatment, most people with glaucoma will lose their vision. Even with treatment, about 10% of people with glaucoma eventually become blind.

Worldwide, glaucoma is the second leading cause of blindness.

Is glaucoma curable?

There is currently no cure for glaucoma, but you can prevent further vision loss with treatment.

Because glaucoma often has no symptoms and currently has no cure, it’s important to have an eye doctor regularly examine your eyes. This will help ensure you can begin treatment before damage to your optic nerve occurs.

Damage to your optic nerve is permanent, but with treatment, you may prevent further vision loss.