Corneal Ulcers: What Contact Lens Wearers Need to Know About Risks and Emergency Care

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 the clock starts ticking the moment you feel pain, notice blurred vision, or see a white spot on your eye. This isn’t something you wait out. This isn’t something you treat with over-the-counter drops. This is an emergency.

What Exactly Is a Corneal Ulcer?

The cornea is your eye’s clear, protective dome. It’s not just a window-it’s a living tissue that needs oxygen, moisture, and protection. A corneal ulcer is when that surface breaks down, forming an open sore. It’s not a scratch. It’s not redness. It’s tissue loss. And it’s almost always caused by infection.

Unlike a simple corneal abrasion, which is a surface scrape that usually heals on its own, a corneal ulcer eats into the deeper layers. Bacteria, fungi, or even a tiny amoeba called Acanthamoeba can invade through a tiny crack or under a lens, then multiply fast. Left untreated, the infection can perforate the cornea, cause permanent scarring, or lead to blindness.

The most common trigger? Wearing contact lenses, especially overnight. A contact lens wearer is 10 times more likely to get a corneal ulcer than someone who doesn’t wear lenses. If you sleep in them? That risk jumps to 100 times higher. It’s not hype. It’s data from the Cleveland Clinic and the FDA.

Why Contact Lenses Are the #1 Risk Factor

It’s not the lenses themselves-it’s how they’re used. Soft contact lenses, especially extended-wear types, act like a sealed dome over your cornea. That blocks oxygen. Your eye starts to suffocate. At the same time, your fingers, your cleaning solution, your shower, your tap water-they all carry germs. When you insert a lens, you’re not just putting plastic on your eye. You’re trapping a biofilm of bacteria, fungi, or worse, right against your cornea.

Here’s how it happens:

• You wear your lenses longer than recommended-say, a week past the 2-week replacement date.
• You rinse them with tap water because you ran out of solution.
• You sleep in them because you’re too tired to take them out.
• You reuse the same case for months without cleaning it.
• You swim or shower with them in.

Each of these habits creates the perfect storm. The lens becomes a breeding ground. The cornea gets damaged. Infection takes hold. And you don’t always feel it right away. That’s the danger.

Red Flags: Don’t Wait for the Pain to Get Bad

The biggest mistake people make? Thinking it’s just “dry eye” or “a tired eye.” Corneal ulcers don’t start with mild discomfort. They start with warning signs that are easy to ignore.

Here’s what to watch for:

• Blurry or hazy vision-not just foggy, but like looking through a dirty windshield.
• Severe eye pain-not a dull ache, but sharp, burning, or throbbing.
• Red or bloodshot eye-not just a little pink, but deep, angry red.
• White or gray patch on the cornea-you might see it in the mirror if you’re lucky.
• Light sensitivity-even normal indoor lighting hurts.
• Excessive tearing or pus-like discharge-your eye is trying to flush out the infection.
• Itching or feeling like something’s stuck-even when you know there’s nothing there.

If you wear contacts and experience even one of these, stop wearing your lenses right now. Don’t wait until tomorrow. Don’t try eye drops from the pharmacy. Call your eye doctor immediately. If you can’t reach them, go to an emergency eye clinic or urgent care center. Time is vision.

How Doctors Diagnose a Corneal Ulcer

You can’t diagnose this yourself. You need specialized tools.

Your eye doctor will likely do this:

• Fluorescein staining-they drop a harmless orange dye in your eye. Under blue light, any damaged areas glow green, showing the exact size and shape of the ulcer.
• Slit-lamp exam-a high-powered microscope with a bright light lets them zoom in on the cornea, seeing layers you can’t even imagine.
• Corneal scraping-if the ulcer looks serious, they gently scrape a tiny bit of tissue to send to a lab. This tells them if it’s bacteria, fungus, or something else.
• Visual acuity test-they check how well you can see before and after treatment.

Newer clinics are even using digital imaging to compare photos of your cornea over time. This helps catch small changes early-before the ulcer grows.

What Happens If You Don’t Treat It

This isn’t a “maybe” scenario. Untreated corneal ulcers lead to one of three outcomes:

1. Permanent scarring-the cornea heals with cloudy tissue, blurring your vision forever.
2. Corneal perforation-the hole gets so deep, your eye leaks fluid. This can cause the eye to collapse.
3. Blindness-the infection spreads inside the eye or causes irreversible damage to the optic nerve.

The FDA doesn’t say this lightly: “Corneal ulcers can lead to blindness.” And it’s not just a warning. It’s a documented reality. Every year, thousands of people lose vision because they waited too long.

Treatment: It’s Not One-Size-Fits-All

Treatment starts the moment you walk in the door. No waiting for lab results. No “let’s see how it goes.”

For bacterial ulcers-which make up the majority-doctors start with strong antibiotic eye drops. Fluoroquinolones like moxifloxacin or gatifloxacin are the go-to. You’ll need to apply them every 30 to 60 minutes at first, then taper off.

For fungal ulcers-often from contaminated water or soil-antifungal drops like natamycin are used. These are harder to treat and take weeks.

For viral ulcers-usually from herpes simplex virus-antivirals like acyclovir or ganciclovir are prescribed.

If the ulcer is large (over 2 mm), close to your pupil, or getting worse after 48 hours, it’s considered “sight-threatening.” That means immediate culture testing and stronger treatment. Sometimes, you’ll need hospitalization for IV antibiotics.

Important: Steroid eye drops might sound like they’d help with swelling-but if you use them without knowing the cause, they can make a fungal or viral infection explode. Only use them if your doctor specifically prescribes them.

If the scar is thick and blocks your vision after healing, a corneal transplant might be your only option. That’s major surgery. And it’s preventable.

How to Prevent a Corneal Ulcer-For Good

You don’t have to give up contacts. But you do have to treat them like medical devices-not accessories.

Here’s what works:

• Never sleep in your lenses-even if they’re labeled “extended wear.” The 100x risk increase is real.
• Replace lenses on schedule-daily, biweekly, monthly. Don’t stretch them.
• Wash your hands-every single time you touch your lenses. Soap and water. Dry with a lint-free towel.
• Use only the solution your doctor recommends-never tap water, saliva, or homemade saline.
• Replace your lens case every 3 months-and rinse it daily with solution, not water. Let it air-dry upside down.
• Take them out for swimming, showering, and hot tubs-water is the #1 source of Acanthamoeba.
• Give your eyes a break-wear glasses at least one day a week.
• Don’t wear lenses if your eyes are red, dry, or irritated-that’s your body’s alarm.

The FDA and eye care professionals agree: proper hygiene cuts your risk by 90%. It’s not complicated. It’s just consistent.

What to Do If You Think You Have One

Step 1: Take out your contacts. Immediately. Don’t clean them. Don’t reuse them. Throw them away.

Step 2: Don’t rub your eye. Don’t put anything in it. Not drops, not water, not tea bags.

Step 3: Call your eye doctor. If they’re not available, go to an emergency eye clinic. In Melbourne, clinics like the Royal Victorian Eye and Ear Hospital or private urgent eye care centers can see you same-day.

Step 4: Bring your lens case and solution with you. The doctor might need to test them.

Step 5: Follow every instruction. Even if you feel better after a day, finish the full course of drops. Stopping early invites resistance and recurrence.

Final Reality Check

Contact lenses are safe-when used correctly. But “correctly” isn’t a suggestion. It’s a rule. The technology has improved. The materials are better. But human error? That hasn’t changed.

Every year, people lose their vision because they thought, “It’s probably nothing.” Or, “I’ll wait until Monday.” Or, “I’ve worn them like this for years.”

Your eyes don’t come with a backup. Once the cornea is scarred, you can’t undo it. But you can prevent it.

If you wear contacts, treat them like your life depends on it-because it does.