7 Lifestyle Habits That Could Be Quietly Damaging Your Corneas

Your cornea is a biological masterpiece. It's the clear, dome-shaped window at the front of your eye that handles about two-thirds of your eye's focusing power. It's also a bit of an anomaly because it's the only tissue in your body that's avascular, meaning it has no blood vessels. Instead of getting nutrients from blood, it breathes oxygen directly from the air.

Because it's so exposed to the outside world, your cornea is highly sensitive. While it's great at healing minor scratches quickly, modern life presents a lot of chronic stressors that can wear it down over time. Stephen Khachikian, MD, and his team see how small, everyday choices can lead to significant cornea problems if you aren't careful.

Which daily habits put your corneas at risk? 

These are seven common habits that can damage your corneas.

1. Water and contact lenses

Never let tap water, lake water, or hot tub water touch your contact lenses. Water often carries a parasite called Acanthamoeba. According to the US Centers for Disease Control and Prevention, about 41.3% of people who get this specific corneal infection end up legally blind in that eye (CDC, 2023).

2. Vigorous eye rubbing

It's tempting to rub an itch, but using your knuckles to grind your eyes can break down the collagen fibers that hold your cornea's shape. This is a major trigger for keratoconus, a condition where the cornea thins and bulges into a cone shape.

3. Excessive screen time

When you're staring at a phone or computer, you don't blink as often as you should. Your blink rate can drop from 20 times a minute to just five (West Broward Eye Care, 2025). This dries out the corneal surface and causes chronic inflammation.

4. Waterline eye makeup

Applying eyeliner to the inner rim of your eyelid can block the tiny oil glands that keep your tears from evaporating. It also migrates directly onto the cornea, acting like abrasive debris every time you blink.

5. Redness-relief eye drops

These drops work by clamping down blood vessels to "get the red out," but they can starve your eye of oxygen. Over time, this leads to a rebound effect where your eyes stay redder than they were before.

6. Unprotected UV exposure

Just as with your skin, your corneas can get a sunburn, known as photokeratitis. Chronic sun damage can also cause fleshy growths, called pterygia, across the corneal surface.

7. Smoking and vaping

Tobacco smoke is a direct irritant that destabilizes your tear film. Even worse, smoking slows down your body's ability to heal corneal abrasions or infections, leaving you vulnerable to scarring for much longer.

How can you protect your vision?

The good news is that most of these risks are easy to manage with a few simple changes. If you work at a computer, follow the 20-20-20 rule: Every 20 minutes, look at something 20 feet away for 20 seconds. This helps reset your focus and encourages you to blink.

We also recommend switching to daily disposable contact lenses if you're prone to infections, as they're the most sterile option. When you're outdoors, wear wrap-around sunglasses that offer 100% UV protection to keep those harmful rays from hitting the sides of your eyes. If your eyes feel itchy or dry, skip the redness-relief drops and reach for preservative-free artificial tears instead.

You don't have to wait until your vision is blurry to start taking care of your corneas. If you're experiencing discomfort, persistent redness, or changes in your sight, our team is here to help. Contact our office in Rapid City, South Dakota, today to schedule a comprehensive eye exam with Dr. Khachikian and ensure that your corneas stay healthy for years to come.