You know smoking is bad for your lungs, heart, and teeth, but it’s no friend to your eyes, either. If that surprises you, you’re not alone. 

“A lot of primary health-care providers, including those in the eye field, are asking patients about smoking,” says John Perez, O.D., an optometrist at the America’s Best Contacts & Eyeglasses in Layton, Utah. “And a lot of patients are taken aback, like, ‘Why are you asking me this? You’re my eye doctor.’”  

The truth is, smoke is a prime source of free radicals, those unstable molecules that wreak havoc on healthy cells and create inflammation in the body—including your eyes, says Dr. Perez. (Pollution, chemical irritants, and UV rays are other sources. Normal cell processes, like cell metabolism, also generate free radicals.) 

A nicotine habit lays the groundwork for problems that lead to vision loss and blindness. Yet less than 10% of U.S. smokers are aware that smoking can cause blindness, according to the results of the International Tobacco Control Four-Country Project survey.  

Vapers are not off the hook, either, Dr. Perez says. While vaping is still too new for scientists to know the long-term effects, he suspects they will be similar to those of smoking cigarettes.  

“It’s a different method, but you’re still putting nicotine into your body,” he says. What’s more, e-cigarettes may be a gateway drug to regular tobacco use and are not effective as a smoking-cessation tool, according to experts at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease. 

Your best bet: Avoid nicotine altogether. Need more convincing? Here are just some of the ways smoking can damage your eyes.  

 Have questions about your eye health or vision? Your America’s Best optometrist is here to help. Click here to find an exam time that fits your schedule.

1. Your Eye-Disease Risk Goes Up (Way Up) 

As a smoker, you’re vulnerable to some of the leading causes of vision loss and blindness in the United States.  

You’re twice as likely as a nonsmoker to develop macular degeneration, and two to three times as likely to develop cataracts, reports the Centers for Disease Control and Prevention (CDC). You’re also at greater risk for diabetic retinopathy, according to the American Academy of Ophthalmology.  

And if you’ve already been diagnosed with eye disease, smoking can make your symptoms worse. That’s because the chemicals in tobacco smoke get into the bloodstream, damaging blood cells and blood vessels. 

“The eye is one of the most energy-demanding organs of the whole body,” says ophthalmologist Rachel Bishop, M.D., a spokesperson for the National Eye Institute (NEI). “The amount of blood flow relative to tissue weight is extremely high. That means anything that impairs blood flow or blood quality can affect the eyes.” 

The good news: If you quit smoking, your risk for some eye diseases becomes almost as low as if you’d never smoked, says Dr. Bishop. 

“Just because you’ve been a smoker for 40 years doesn’t mean you can’t benefit from quitting,” she says. “It’s never too late to quit smoking, and quitting is always a good thing for your health.”  

2. Your Eyes Start to Resemble the Sahara 

Millions of Americans have experienced dry eye, but smokers tend to have it worse. That’s because tobacco smoke breaks down the protective layer of tear film that shields your eyes. 

“Think of the tear film as a moisture coating on the surface of your eye,” says Dr. Bishop. “Similar to the mucous membranes that line your mouth, nose, and gut, the eye’s surface is designed to be wet all the time. Anything that impairs the quality of the tear film produces a problem.” 

Dry eye symptoms can range from mildly irritating (itchy, burning) to downright debilitating, she says. Severe cases can even interfere with your vision. 

3. Your Eye Allergies Get Worse 

Tobacco smoke is an irritant, says Dr. Perez. “It’s constantly pounding on the cornea.” (Quick reminder: The cornea is the clear, dome-shaped surface that covers the front of the eye. It plays a key role in focusing your vision, according to the NEI.) That can trigger inflammation—red, painful, itchy eyes—and amplify allergy symptoms, note experts at the National Institute of Environmental Health Sciences. 

4. Your Baby Blues Turn Bloody Red  

All that dryness and irritation can lead to chronic red eyes. Plus, the oxidative stress from the excess free radicals can accelerate aging on the delicate skin under and around the eyes, says Dr. Perez. 

“It can make 40-year-olds look like they’re 60,” he says.  

5. Your World Looks Less Colorful 

For tobacco users, the world may appear less vibrant, and not just because they’re viewing it from inside a cloud of smoke. 

In a study of smokers and nonsmokers ages 18 to 40 that was published in the International Journal of Ophthalmology, the smokers scored much worse on a color-vision test than nonsmokers did. Nonsmokers scored about 50 errors, on average, while smokers scored 65. 

“Smoking affects the macula, and that’s where color sensors are,” explains Dr. Perez. “If you’re damaging the vascular system that feeds the macula, then you’re having macular degeneration processes, which are going to affect color vision.” 

6. Your Contact Lenses Stop Working 

Smokers have a harder time wearing contact lenses than nonsmokers due to the dry-eye effects of smoking.  

“The cornea wasn’t really meant to carry a piece of plastic on its surface,” says Dr. Bishop. “Most people with healthy eyes can tolerate contact lenses. But for smokers, contact-lens intolerance is higher.” 

Smokers also have a greater chance of contact lens–induced infections like microbial keratitis and corneal ulcer—even if they’re wearing daily disposable lenses.  

7. Your Optic Nerve Begins to Suffocate 

Because smoking damages the blood vessels, it decreases or blocks the amount of oxygen and blood flow reaching your optic nerve, Dr. Perez says. That can cause lasting damage to this nerve, leading to sudden vision loss in one or both eyes. 

It’s called ischemic optic neuropathy, and it usually cannot be fixed, according to the American Academy of Ophthalmology. 

Your best bet: prevention.  

Doctors know that quitting smoking is hard. If you smoke, talk to your primary-care provider about cessation programs, Dr. Perez suggests. You can find free resources to help you quit at Smokefree.gov.  

He also recommends speaking with a nutritionist, who can help you replenish your body’s antioxidant supply—the right foods (and not just carrots!) can help neutralize free radicals. With these steps, you may reverse much of the damage that’s been done.