A corneal ulcer isn’t just a sore eye-it’s an open wound on the clear front surface of your eye that can steal your vision if ignored. For the 85 million people worldwide who wear contact lenses, this isn’t a rare scare. It’s a real, preventable danger. And if you’re wearing your lenses overnight, you’re 100 times more likely to develop one than someone who doesn’t. This isn’t fearmongering. It’s data from the Cleveland Clinic and the FDA. The moment you notice pain, redness, or blurry vision while wearing contacts, you need to act-fast.

What Exactly Is a Corneal Ulcer?

The cornea is your eye’s clear front window. It’s tough, but not invincible. A corneal ulcer is an open sore that forms when the surface breaks down, often because of an infection. It’s not the same as a scratch. A corneal abrasion is a surface scrape that usually heals on its own. An ulcer? That’s tissue loss. Bacteria, fungi, or viruses burrow in, eat away at the cornea, and leave behind a crater-like wound. Left untreated, it can scar your cornea, warp your vision, or even lead to blindness.

Why Contact Lenses Are the #1 Risk Factor

You might think your lenses are clean because you rinse them with solution. But here’s the truth: your fingers, your sink, your shower, even your pillowcase can carry harmful microbes. When you wear contacts-especially overnight-you’re creating the perfect storm.

Contacts block oxygen from reaching your cornea. That weakens its natural defenses. Then, bacteria from your hands or dirty solution get trapped under the lens. The longer you wear them, especially while sleeping, the more time those germs have to multiply. Studies show contact lens wearers are 10 times more likely to get a corneal ulcer than non-wearers. And if you sleep in them? That jumps to 100 times higher risk.

Soft, extended-wear lenses are the worst offenders. They’re designed to be worn for days or weeks, but that convenience comes at a cost. Even if you don’t sleep in them, wearing them longer than recommended-say, a week past their replace-by date-increases your risk. Scratched lenses are another silent threat. A tiny tear you can’t see can harbor bacteria and scratch your cornea as you blink.

What Symptoms Should You Never Ignore?

If you feel any of these, stop wearing your lenses right now and call your eye doctor:

• Severe eye pain, even when you’re not touching your eye
• Blurry, hazy, or foggy vision that doesn’t clear up
• Red, bloodshot eyes that look worse than just tired
• White or gray spot on the clear part of your eye (the cornea)
• Excessive tearing or thick, pus-like discharge
• Extreme sensitivity to light-you can’t stand even normal indoor lighting

These aren’t "wait-and-see" symptoms. They’re red flags. The longer you wait, the more damage the infection does. A small ulcer can turn into a deep scar in 24 to 48 hours. And once the cornea is scarred, your vision may never fully recover.

How Doctors Diagnose It

Your eye doctor won’t just look at your eye with a flashlight. They’ll use specialized tools:

• Fluorescein staining: A harmless orange dye is dropped in your eye. Under blue light, any damaged areas glow green-making the ulcer visible.
• Slit-lamp exam: A high-powered microscope lets the doctor see the ulcer’s depth, size, and shape in detail.
• Corneal scraping: If the ulcer looks serious, they’ll gently take a tiny sample of the infected tissue and send it to a lab. This tells them if it’s bacterial, fungal, or viral.
• Visual acuity test: They’ll check how well you can see before and after treatment to track progress.

Newer imaging systems can even take detailed photos of the ulcer and compare them over time. This helps catch problems earlier and adjust treatment faster.

How It’s Treated-And Why Speed Matters

Treatment starts the moment you walk in the door. Waiting even a day can mean the difference between full recovery and permanent vision loss.

For mild ulcers, doctors usually start with fluoroquinolone antibiotic eye drops-a broad-spectrum treatment that covers most common bacteria. You’ll need to use them every hour or two at first, then taper off as it heals.

If the ulcer is large (over 2 mm), close to the center of your vision, or getting worse after 48 hours, they’ll do a corneal scraping right away. That way, they can target the exact germ causing the problem:

• Bacterial: Fluoroquinolones or other antibiotics
• Viral: Antiviral drops like acyclovir
• Fungal: Special antifungal medications-these are harder to treat and take weeks

Important: Never use steroid eye drops unless your doctor prescribes them. They can reduce swelling, but they also weaken your eye’s ability to fight infection. Used wrong, they can make a bad ulcer deadly.

In severe cases, when the cornea is badly scarred or perforated, a corneal transplant may be needed. It’s a major surgery, and recovery takes months. But it’s the only way to restore vision after serious damage.

How to Prevent a Corneal Ulcer

The best treatment is avoiding the problem altogether. Here’s what actually works:

• Never sleep in your lenses. Even "extended-wear" ones. The 100x risk increase isn’t a myth-it’s a warning.
• Replace your lenses on schedule. Daily, weekly, monthly-stick to it. Don’t stretch them.
• Wash your hands before touching your lenses. Soap and water. Dry with a lint-free towel.
• Use only recommended solutions. Never use tap water, saliva, or homemade saline. Water carries dangerous germs like Acanthamoeba, which cause hard-to-treat infections.
• Take your lenses out before swimming or showering. Even a splash can introduce microbes.
• Give your eyes a break. Wear glasses at least one day a week. Let your cornea breathe.
• Don’t reuse solution. Always dump the old solution and refill the case daily. Clean your case weekly with hot water and let it air dry.

What to Do If You Think You Have One

If you notice any symptoms:

1. Take your contacts out immediately.
2. Don’t rub your eye. Don’t put in new lenses.
3. Don’t wait until your next appointment. Call your eye doctor right away.
4. If you can’t reach them, go to an urgent eye clinic or emergency room. Time is vision.

Most clinics have after-hours emergency lines. Use them. A corneal ulcer isn’t something you can treat with over-the-counter drops. It needs professional care, and fast.

Final Reality Check

Contact lenses are safe-if you treat them like medical devices, not fashion accessories. They’re not like glasses. You can’t just toss them in your bag and forget them. They require daily care, discipline, and respect.

The FDA, the Cleveland Clinic, and the American Academy of Ophthalmology all agree: improper lens use can lead to blindness. But the good news? You control the risk. Follow the rules. Listen to your eyes. And if something feels wrong-don’t ignore it. Your vision isn’t something you can afford to gamble with.