What is glaucoma?

Glaucoma symptoms are hard to spot — protect your vision with regular eye exams

Because most of us use our vision every day without much thought, it’s easy to take clear sight for granted. But vision loss from a common condition like glaucoma can occur if left untreated.

Glaucoma can develop at any age, but it’s most common in older adults. And it often comes without early warning signs.

That’s why knowing your risk factors, following healthy eye habits and getting regular comprehensive eye exams are essential.

“While there’s no cure for glaucoma, treatment can control eye pressure and slow or even stop vision loss,” says Tatiana Franco, MD, an ophthalmologist specializing in glaucoma at Geisinger. “Many forms of glaucoma are treatable, and most people maintain useful vision for life with an early diagnosis, treatment and regular monitoring.”

Here’s what to know about glaucoma — and steps you can take now to preserve your sight.

What is glaucoma?

Glaucoma is a group of eye conditions that slowly damage the optic nerve, often due to increased pressure inside the eye. The optic nerve is the pathway that carries visual signals from your eye to your brain, allowing us to see.

There are several types of glaucoma, but the most common is called open-angle glaucoma, where the drainage angle formed by the cornea and iris remains open, but fluid drains from the eye too slowly.

In a healthy eye, clear fluid constantly flows in and out to nourish the eye’s tissues. But when fluid stops draining, it builds up and creates too much pressure in the eye. Over time, this pressure can damage the optic nerve and lead to peripheral (side) vision loss and blindness, if left untreated.

“Glaucoma is most often associated with high pressure in the eye, but some people can have the condition with normal eye pressure and still lose their vision without treatment,” says Dr. Franco. “High eye pressure is not the only sign of glaucoma.”

Glaucoma symptoms

Glaucoma often begins without early warning signs. Because damage to the optic nerve occurs slowly, eye changes are gradual and painless — and the reason it’s sometimes referred to as the “silent thief of sight.”

However, as the disease progresses, glaucoma symptoms can include:

Patchy blind spots in peripheral vision
Blurred vision
Presence of halos around lights
Difficulty adapting to low light and increased glare sensitivity

Having these symptoms doesn’t necessarily mean you have glaucoma. But it’s still important to talk to your eye doctor, as these could be signs of an underlying health issue.

Glaucoma risk factors

The risk of glaucoma increases with a combination of genetic and lifestyle factors.

Those with the highest risk of glaucoma include:

Anyone with a family history of glaucoma, especially in a parent or sibling
People over age 60, or African Americans over age 40
Those with chronic conditions like diabetes, high blood pressure or thyroid disease
People with extreme nearsightedness or farsightedness
Anyone that has thin corneas, a large optic nerve or elevated eye pressure
Someone who previously had a severe eye injury
People who take corticosteroid medications, such as prednisone

“Understanding glaucoma causes can help you focus on modifiable risk factors,” says Dr. Franco. “While glaucoma can’t always be prevented, managing overall health — especially blood sugar and blood pressure — may reduce risk or slow progression.”

If you have risk factors, talk with your eye care professional about how often you should be screened.

How to prevent glaucoma

You can’t always prevent glaucoma, but you can prevent vision loss. Reducing your modifiable risk factors and early detection and treatment can slow — or even stop — progression.

Dr. Franco offers 3 prevention steps to preserve your sight:

Have regular eye exams

Routine eye exams are the most important prevention step — and the only way to catch glaucoma earlier. Your eye doctor can measure eye pressure, evaluate the drainage of the angle, examine your optic nerve, check corneal thickness and assess your visual field.

The American Academy of Ophthalmology recommends most adults have a comprehensive eye exam every 1 to 2 years, but frequency depends on your age, health and risk factors.

“Because damage is often silent at first, staying on schedule with eye exams is one of the best ways to protect your sight,” says Dr. Franco. “And if you don’t like dilated eye exams, there are alternative options that use specialized pictures, which are just as effective in diagnosing glaucoma.”

Support eye health

A healthy lifestyle supports good eye health — and reduces your risk of glaucoma and other eye conditions.

Some general tips include:

Eat a balanced diet rich in leafy greens, colorful fruits and omega-3 fatty acids
Stay physically active to promote healthy blood flow
Avoid smoking
Manage chronic conditions like diabetes and high blood pressure

Wear eye protection

Serious eye injuries can increase your chances of developing glaucoma.

Wear protective eyewear like safety goggles when using power tools or playing sports. And don’t leave the house without sunglasses — even on cloudy days — to protect your eyes from the sun’s harmful UV rays. Be sure to reach for ones that block 100% of both UVA and UVB rays.

“Preventing glaucoma starts with taking charge of your eye health and vision,” says Dr. Franco. “And that means managing your risk factors and getting regular eye exams. Glaucoma is detectable and treatable early on, so you can increase your odds of slowing or stopping progression in its tracks.”