Glaucoma: What You Need to Know to Protect Your Sight

As a leading cause of blindness in the US, glaucoma is a serious eye disease that needs to be detected and treated as early as possible. Learn more about who glaucoma affects, how it’s diagnosed and treated, and what kind of outcomes patients with glaucoma can expect.


Sally Wadyka

| Reviewed by

Quinn Wang, MD

Glaucoma is a condition that damages the optic nerve, impacting your ability to see. It affects nearly 3 million people in the U.S. and is the second most common cause of blindness in the world. The condition can occur at any age, but it more often affects older adults.


Glaucoma is often symptomless, stealing vision before you even realize you have the disease. In fact, about half of the people who have glaucoma don’t know they have it, which is why it’s important to have regular eye exams as you age.


There are currently no treatments that reverse glaucoma-related damage to the optic nerve. But medication (and in some cases, glaucoma surgery) can effectively slow the progression of the disease and save your vision.


What is glaucoma?

Glaucoma is a disease that damages the optic nerve, which is a cable-like structure that connects the back of the eye to the brain. The optic nerve, a bundle of more than 1 million nerve fibers, is like the control center of your eyesight. It sends sensory information for vision  from the retina to your brain. Those signals translate into your ability to see clear images. Damage to the optic nerve can cause vision loss.


There are several types of glaucoma, most of which result from a buildup of pressure within the eye. Over time, the pressure on the optic nerve impairs blood flow and causes irreversible nerve damage. Some people develop glaucoma in both eyes, but it may be worse in one eye.


The most common types of glaucoma include:

  • Open-angle glaucoma: Nine out of 10 people in the U.S. with glaucoma have this type. It results from pressure building up within the eye. This increased intraocular pressure (aka IOP) slowly damages the optic nerve over years. Vision loss occurs silently and is usually only very noticeable in late stages, when patients suffer from tunnel vision. However, elevated IOP is one of the earliest signs of glaucoma, and with timely treatment, the rate of vision loss can be slowed down. 
  • Normal tension glaucoma: This is a type of open-angle glaucoma that affects people whose eye pressures (aka IOP) are normal.
  • Angle-closure glaucoma: This type is also called closed-angle, narrow-angle or acute glaucoma. It is much more rare than open-angle glaucoma. With this type, fluid and pressure builds up quickly, causing sudden vision changes, red eyes, nausea and intense eye pain. Angle-closure glaucoma is a medical emergency. It requires immediate attention in order to prevent permanent vision loss.
  • Congenital glaucoma: This rare condition affects about 1 in 10,000 babies in the U.S. Babies with congenital glaucoma have trouble draining fluid from their eyes. Surgery can help prevent vision loss; without treatment, patients will go blind. 


Who is most likely to get glaucoma?

Although different types of glaucoma can affect people of all ages, the most common type (open-angle glaucoma) is linked to age. People over 40 are more likely to get glaucoma, and that risk increases as you get older. The condition is six times more common in people over 60 than it is in younger adults.


Other risk factors for glaucoma include:

  • Being African American or Latino: African Americans are 15 times more likely to be visually impaired from glaucoma than Caucasians.
  • Having a family history of glaucoma
  • Diabetes
  • High blood pressure
  • Long-term use of corticosteroid medication
  • Eye injury or surgery 

Can I prevent glaucoma?

You may be able to reduce your risk of glaucoma by staying healthy—especially by taking steps to prevent diabetes and high blood pressure (both of which greatly increase your risk of glaucoma).


The best way to prevent glaucoma-related vision loss is to see your eyecare professional for recommended eye exams. The American Academy of Ophthalmology recommends a baseline screening for all adults at age 40, then every 2 to 4 years between age 40 and 54 and every 1 to 3 years from age 55 to 64. After age 65, you should have a comprehensive eye exam annually. If you have risk factors for glaucoma, you may need more frequent screenings, starting earlier in life.


Understanding glaucoma symptoms

The reason that regular, comprehensive eye exams are so important is that glaucoma often goes unnoticed in its early stages. The vision loss comes on so gradually that the changes may be too subtle to notice.


Glaucoma usually affects your peripheral vision (your ability to see to the side while looking straight ahead). As you lose more of your peripheral vision, you may miss steps going downstairs, have more blind spots when driving or even find parts of words missing when you read.


Diagnosing glaucoma

During a comprehensive eye exam, your provider performs several tests, including:

  • Visual acuity tests, to assess how clearly you can see both far away and close up
  • Tonometry, a test that measures the pressure inside your eyes (your IOP)
  • Visual field test, often called a perimetry exam, to identify any changes in your  peripheral vision; specifically, it looks for blind spots and patterns of vision loss that are consistent with glaucoma
  • Evaluating the optic nerve to look for damage, which shows up as an increased cup-to-disc ratio
  • Measuring the thickness of the cornea (having a thinner cornea can increase your risk of glaucoma)
  • Examining the draining channels in the eyes to see how well fluid can pass through. When there is greater outflow resistance, the pressure in the eye gradually increases, which can lead to glaucoma. 

Treating glaucoma

Identifying and treating glaucoma as soon as possible is critical. No treatment currently exists to repair damage to the optic nerve. Any vision you lose to glaucoma is permanent. But if you catch it in its earliest stages, you can start treatment before you even have any noticeable vision changes.


The main goal of glaucoma treatment is to lower the pressure in the eye to prevent further damage to the optic nerve. In most cases, medicated eye drops can manage the condition. Using them daily as prescribed can slow down progression and save your vision.


If medication doesn’t effectively lower your eye pressure, you may need glaucoma surgery. Options could include using a laser or other surgical procedure to help drain fluid out of your eyes and lower the pressure.


For acute, angle-closure glaucoma, doctors use more powerful medications and possibly surgery to immediately lower dangerously high eye pressure.


Glaucoma treatment outcomes

Thanks to effective treatment options, most people with glaucoma do not lose their sight. Glaucoma may impact your vision, but with treatment, you can slow the progression of the disease. Be sure to see your eyecare provider as recommended for comprehensive eye exams. Catching glaucoma early can save your eyesight.



Merck Manual [Consumer Edition]

American Optometric Association

Glaucoma Research Foundation

National Eye Institute

American Academy of Ophthalmology


Taking good care of your eyes and your overall health can go a long way toward preventing age-related eye conditions. Eating an eye-healthy diet that includes lots of antioxidant-rich fruits and vegetables slows down the formation of cataracts and reduces your risk of macular degeneration. Getting plenty of exercise and maintaining a healthy weight can prevent diseases like diabetes and high blood pressure--both of which affect vision and eye health. And while you may not be able to prevent the presbyopia (and need for reading glasses) that comes with getting older, your eyecare professional can make sure you get the correct vision correction to see clearly.


The sun’s rays contain damaging ultraviolet (UV) light. The same UV rays that burn your skin and lead to skin cancer also affect your eyes. Staring directly into strong sunlight can damage the retina. And repeated sun exposure over time can lead to cataracts, benign growths on the eyes and even eye cancer. Protect your eyes anytime you’re in the sun by wearing sunglasses that block both UVA and UVB rays.


Some people claim that by correcting your vision with prescription glasses or contacts, you’re weakening your eyes—which then leads to worse vision. Their “proof” is that after wearing your corrective prescription for a while, your vision appears blurrier when you’re not wearing it. But that’s likely because you’re now used to seeing the world in clear, crisp detail—and in contrast, your uncorrected vision appears fuzzier. Getting the proper vision correction for your eyes is essential for your eye health. Don’t try to tough it out if you can’t see clearly. Visit your eyecare professional for an in-person or virtual vision screening.


Not having a bright enough light may make it harder to clearly see the words on the page, but it won’t damage your eyes or permanently impact your vision. Because you’re straining to see, you might get a headache or other symptoms of eyestrain. If you want to read in bed without illuminating the entire bedroom, get a reading light that provides just enough brightness to see your book clearly. 


LASIK surgery corrects your distance vision only, so people who are nearsighted benefit most from it. But LASIK doesn’t affect the lens of the eye, the part that helps you focus up close. As you get older, changes to the lens impact your ability to see close up. So even if you have LASIK in your 20s or 30s, you’ll most likely still need reading glasses by the time you hit your 40s or 50s.


Having your face right up next to the bright screen may give you a headache or even cause some temporary eyestrain or fatigue, but it won’t damage your vision. Children are more prone to this behavior than adults—which may be because children can focus close up better than adults can. But if your child can only see the television clearly when sitting close (and has to hold other things close to see them clearly), they may be nearsighted. Taking your child to an eyecare professional for a vision exam will help determine if they need glasses to see clearly.


Most eyecare professionals recommend removing—and thoroughly cleaning—your contacts every night. Even if you use extend-wear lenses that are approved for use a week or month at a time, it’s always safer to give your eyes a nightly break. Your contacts are more likely to accumulate bacteria when you leave them in 24/7, and that can lead to eye infections. Sleeping in your contacts also prevents essential oxygen from getting to your corneas. If you must sleep in your contacts, make it a once-in-a-while event and ask your eyecare provider about contacts that are specially formulated to let more oxygen through. 


Carrots (along with other vegetables like sweet potatoes and dark leafy greens) contain high amounts of beta-carotene, which the body converts to vitamin A. Vitamin A is essential for eye health, and a deficiency of the nutrient is the leading cause of childhood blindness in developing countries. In the U.S., vitamin A deficiency is rare, and few people get so little it could impact their eyesight. Also, there’s no evidence that beta-carotene affects the sharpness of your vision or can prevent near or farsightedness. So while getting lots of beta-carotene in your diet may help keep your eyes healthy, no amount of carrots is going to actually improve your vision and allow you to toss out your glasses or contacts. 


The jury is still out on how effective blue light glasses are for eyestrain. One recent study found they made no difference in eyestrain symptoms during a two-hour-long computer task. But some experts feel they may help alleviate eyestrain and fatigue during prolonged, cumulative screen time. Either way, blue glasses alone won’t solve the problem of too much screen time. The best way to reduce eyestrain is to limit screen time and take frequent breaks when you do need to spend several hours at your computer.


The jury is still out on how effective blue light glasses are for eyestrain. One recent study found they made no difference in eyestrain symptoms during a two-hour-long computer task. But some experts feel they may help alleviate eyestrain and fatigue during prolonged, cumulative screen time. Either way, blue glasses alone won’t solve the problem of too much screen time. The best way to reduce eyestrain is to limit screen time and take frequent breaks when you do need to spend several hours at your computer. 

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