Corneal abrasion
Based on Wikipedia: Corneal abrasion
The Scratch You Never See Coming
Your cornea is remarkably tough for something so delicate. This transparent dome at the front of your eye, no thicker than a credit card, takes a beating every single day. It survives wind, dust, the occasional eyelash gone rogue. But sometimes, in the space of a blink, something slips past your defenses.
A fingernail. A tree branch on a morning jog. A contact lens worn just a few hours too long.
And suddenly you understand, in the most visceral way possible, that your eye has a surface—and that surface can be damaged.
What Happens When Your Eye Gets Scratched
A corneal abrasion is exactly what it sounds like: a scratch on the cornea. But that clinical description hardly captures the experience. People who've had one often describe a sensation that's equal parts pain and wrongness—as if something foreign has taken up residence in their eye and refuses to leave. Which, in a sense, is precisely what the exposed nerve endings are reporting.
The symptoms arrive in a recognizable constellation. Pain, of course. But also an intense sensitivity to light that makes you want to retreat to a dark room. Excessive tearing, as your eye floods the zone with its best natural defense. A persistent feeling that something is in there, even when nothing is. And squinting—so much squinting that your face begins to ache from the effort.
Vision often blurs, though not from the scratch itself. The culprit is usually corneal swelling combined with the waterfall of tears your eye keeps producing. Some people wake up with crusty buildup around their eyes, the dried residue of their body's overnight attempt to heal the wound.
Here's the reassuring part: most corneal abrasions heal completely within three days. The cornea regenerates its surface cells faster than almost any other tissue in your body. But those three days can feel very long indeed.
The Usual Suspects
If you're trying to avoid a corneal abrasion, understanding the common causes helps. The list reads like a catalog of everyday activities that turned unexpectedly violent.
Fingers and fingernails rank near the top. Parents of young children know this scenario intimately: a toddler's enthusiastic gesture, a tiny finger moving faster than your reflexes can compensate, and suddenly you're clutching your eye in shock. The scratch from a fingernail can be surprisingly deep because nails have a harder, sharper edge than you might expect.
Tree branches and plants claim their share of victims too. Gardeners, hikers, and anyone who's ever walked through overgrown vegetation at face height has flirted with this particular danger. The eye's defensive blink reflex is fast, but branches swinging back into position are sometimes faster.
About a quarter of all corneal abrasions happen at work. Metal workers, carpenters, welders—anyone who deals with flying particles or debris works in an environment where eye protection isn't just sensible, it's essential. A tiny metal shard moving at high speed can do tremendous damage to the corneal surface.
But the most insidious cause might be contact lenses.
The Contact Lens Problem
Contact lenses represent a fascinating bargain. You place a piece of precisely shaped plastic or silicone directly onto one of your most sensitive organs, and in exchange, you get clear vision without glasses. Millions of people make this bargain every day, and for most of them, it works perfectly well.
But lenses that have been worn too long—especially overnight—create conditions ripe for trouble. The damage often occurs not while the lens is in place, but when you remove it. A lens that's been sitting on a dried-out cornea can stick slightly, and removing it can peel away a layer of epithelial cells along with the plastic.
Soft contact lenses worn overnight deserve special concern. Extended wear creates a warm, moist environment against your cornea—essentially an ideal breeding ground for bacteria. One organism in particular haunts eye doctors: a bacterium called Pseudomonas aeruginosa. This gram-negative pathogen forms biofilms on contact lenses and loves nothing more than an already-damaged cornea to colonize.
When a contact lens wearer shows up with a corneal abrasion, doctors treat it as a more serious situation than the same scratch in someone who doesn't wear contacts. The risk of bacterial infection is dramatically higher. In severe cases, Pseudomonas infections can penetrate the cornea and cause permanent vision loss.
This is why eye doctors never put a pressure patch on a contact lens wearer's corneal abrasion. In non-contact lens cases, patching used to be standard treatment. But research showed that the warm, dark, moist environment under a patch—the same conditions that make it feel soothing—also accelerates bacterial growth. For contact lens wearers already at elevated infection risk, patching proved to be exactly the wrong approach.
A Genetic Predisposition
For some unfortunate individuals, corneal abrasions aren't a one-time accident but a recurring nightmare. The culprit is often a condition called lattice corneal dystrophy, a genetic disorder that fundamentally changes the cornea's structure.
In lattice dystrophy, abnormal protein fibers made of amyloid—the same type of protein implicated in Alzheimer's disease—accumulate within the middle and front layers of the cornea. Under a slit lamp microscope, an eye doctor can see these deposits as a network of overlapping dots and branching filaments, creating a pattern that resembles a lattice. Hence the name.
The lattice lines grow progressively more opaque over time, eventually clouding vision. But the more immediate problem is what happens at the surface. The abnormal proteins can accumulate beneath the epithelium, causing it to erode spontaneously. This phenomenon, called recurrent epithelial erosion, means the cornea essentially keeps scratching itself.
People with this condition experience something cruel: even blinking can cause pain. The involuntary act that normally protects and lubricates your eye becomes an enemy, each blink potentially reopening a wound that never quite finishes healing.
Making the Diagnosis
When you arrive at a doctor's office or emergency room convinced something terrible has happened to your eye, the examination follows a predictable pattern. The key tool is a slit lamp microscope—essentially a very bright light source combined with a binocular microscope that lets the examiner peer at your cornea under high magnification.
But the cornea is transparent, which makes scratches hard to see directly. So doctors use a clever trick: fluorescein dye. This yellow-orange liquid, when dropped onto the eye, fills in any defects in the corneal surface. Under a cobalt blue light, the dye glows bright green wherever it has collected. A smooth, healthy cornea shows nothing. A scratched cornea lights up like a map of exactly where the damage occurred.
The examination includes a careful search for foreign bodies. The doctor will flip your eyelids inside out—a disconcerting experience if you've never had it done—to check whether anything is hiding against the inside surface. It's surprisingly common for a particle to lodge under the upper lid and keep scratching the cornea with every blink.
One specific scenario raises alarm bells: anyone who reports an eye injury after using hammers or power tools. High-velocity particles from these tools can penetrate the eye entirely, creating damage far beyond a simple surface scratch. When doctors hear "hammering" or "power tools," they immediately consider whether a foreign body might have embedded itself inside the eye, requiring urgent ophthalmology consultation.
Getting That Foreign Body Out
If examination reveals a foreign particle on the cornea, it needs to come out. Leaving it in place risks further damage and, if the particle contains iron, creates an additional problem: rust. Iron-containing particles begin oxidizing almost immediately, and rust in the cornea is considerably harder to deal with than the original foreign body.
The removal procedure sounds medieval but is actually quite refined. The patient lies in a comfortable position with the affected eye closest to the doctor. A drop of local anesthetic goes in—oxybuprocaine is the usual choice because it works within 20 seconds. The doctor asks the patient to fix their gaze on a specific point on the ceiling, which centers the foreign body between the eyelids and keeps it as accessible as possible.
For superficial particles sitting loosely on the corneal surface, a cotton-tipped applicator often does the job. The doctor gently rolls the particle free while the patient concentrates on not blinking—easier than it sounds with anesthetic in place.
Deeper or more embedded particles require sterner measures: a hypodermic needle or small surgical blade. The doctor uses the tip to carefully lift the foreign body free, along with any surrounding rust ring. This sounds terrifying, but the anesthetic makes it painless, and a skilled practitioner can complete the extraction in seconds.
After removal, the eye gets flushed with sterile saline to wash away any remaining debris. Then the real work of healing begins.
Treating the Scratch
Modern treatment for corneal abrasions focuses on three goals: preventing infection, speeding healing, and managing pain. The approach has evolved considerably over the years as research debunked some traditional practices.
Topical antibiotics form the foundation of treatment. The scratched cornea is an open wound, and the eye's warm, moist environment welcomes bacteria. Ointments are generally preferred over drops because they provide more lubrication for the damaged surface.
But the choice of antibiotic matters. For contact lens wearers, doctors prescribe antibiotics with activity against Pseudomonas—ciprofloxacin, gentamicin, or ofloxacin. Regular non-contact lens abrasions typically get treated with erythromycin or bacitracin ointment. The distinction exists because contact lens wearers carry different bacteria on their eyes, and treating with the wrong antibiotic leaves them vulnerable to exactly the infection they're trying to prevent.
Pain management has become more sophisticated. Paracetamol (known as acetaminophen in the United States) helps with general discomfort. Nonsteroidal anti-inflammatory drugs like ibuprofen, taken orally, reduce both pain and inflammation. Topical NSAID drops—particularly diclofenac and ketorolac—can be quite effective, though doctors use them cautiously because they may slow healing.
Some clinicians also prescribe cyclopentolate drops, which paralyze the pupil and the ciliary muscle behind it. The ciliary muscle normally controls the shape of your lens for focusing. When the cornea is injured, this muscle can go into spasm, creating a deep, aching pain. Paralyzing it provides relief. However, you'll need to avoid driving and bright lights while the drops are in effect, and your near vision will be blurry until they wear off.
What We've Stopped Doing
Medical treatment sometimes advances by discovering that what we thought helped actually doesn't. Corneal abrasion treatment offers several examples.
Eye patches were long considered standard care. The logic seemed sound: protect the damaged surface from further irritation, reduce exposure to light, and give the eye a chance to rest. Patients often reported that patches felt soothing.
But studies showed patches don't actually speed healing. Worse, they reduce oxygen delivery to the cornea and create the warm, moist environment that bacteria love. Today, patches are rarely recommended for simple abrasions.
Mydriatic drops—medications that dilate the pupil and were once given to reduce ciliary muscle spasm—have also fallen out of favor for routine use. While they can help with severe spasms, the evidence doesn't support using them for typical abrasions.
Topical anesthetics represent a more complicated story. These drops, like the tetracaine or oxybuprocaine used during examination, dramatically relieve pain. Patients sometimes want to take them home. But there are real concerns about safety with repeated use—potential for delayed healing, masked symptoms of worsening infection, and risk of additional corneal damage. Most guidelines recommend against dispensing anesthetic drops for home use, though the research continues to evolve.
When Things Go Wrong
Complications from simple corneal abrasions are relatively rare—roughly 10% of cases—but they can be serious.
Bacterial keratitis represents the most feared outcome. This infection of the cornea can progress rapidly, sometimes penetrating into deeper layers within 24 to 48 hours. The cornea becomes increasingly opaque, vision deteriorates, and without aggressive antibiotic treatment, permanent scarring or even perforation of the cornea can occur. This is why the antibiotic prophylaxis isn't optional—it's a critical part of preventing a nuisance injury from becoming a vision-threatening emergency.
Corneal ulcers can form when the epithelium fails to heal properly and the underlying tissue becomes damaged. Unlike the superficial abrasion, an ulcer creates a crater in the cornea that heals with scarring. Depending on location, this scarring can permanently affect vision.
Iritis—inflammation of the iris, the colored part of your eye—sometimes accompanies corneal abrasions. The immune system, mobilizing to address the injury, sometimes gets overenthusiastic and attacks structures adjacent to the wound. Iritis causes deep, aching pain, light sensitivity, and can lead to adhesions between the iris and lens if not treated.
Perhaps the most frustrating complication is recurrent erosion syndrome. In some people, the healed epithelium doesn't adhere properly to the basement membrane underneath. Weeks, months, or even years later, the poorly attached cells can spontaneously peel away—often upon waking, when dry lids stick slightly to the cornea and the first blink of the day tears cells loose. Patients describe being "cured" of their abrasion only to wake one morning with all the original symptoms returned.
An Ounce of Prevention
Given how unpleasant corneal abrasions are, prevention deserves serious attention. The strategies are straightforward even if consistently following them takes discipline.
Protective eyewear saves eyes. This isn't controversial—it's physics. A piece of polycarbonate between your cornea and a flying metal shard or wood chip absorbs an impact that your eye cannot. Workers in machine shops, construction sites, and woodworking environments should consider safety glasses as non-negotiable as a hard hat.
But safety glasses aren't one-size-fits-all. Welders need helmets with lenses that block ultraviolet light, or they risk UV keratitis—essentially a sunburn on the cornea. Chemistry and biology labs require splash-proof goggles that seal against the face. Contact sports may call for sport-specific goggles designed to absorb impacts while allowing full peripheral vision.
People with vision in only one eye face a particular calculus. An injury that would be serious but recoverable for most people becomes potentially life-altering when only one functioning eye exists. The standard advice for monocular individuals is to wear polycarbonate lenses or protective eyewear during any activity that poses risk—which, when you start thinking about it, includes a surprising number of daily activities.
Contact lens wearers can reduce their risk substantially by following guidelines that often get ignored. Never sleep in lenses not specifically designed for overnight wear. Replace lenses according to schedule, not when they "feel like they need it." Use fresh solution every day—never top off old solution. Remove lenses before swimming. And never, ever try to stretch a two-week lens into a month of wear.
These precautions might seem excessive until you've experienced a corneal abrasion—or worse, a Pseudomonas infection. Then they seem like obvious wisdom you wish you'd followed all along.
The Numbers
Corneal abrasions are more common than you might expect. In the United States, roughly 3 out of every 1,000 people experience one each year. That translates to nearly a million cases annually.
Men are affected more often than women, reflecting patterns of employment in high-risk occupations and, perhaps, differences in risk-taking behavior. The peak age range is the 20s and 30s—decades of maximum physical activity and maximum contact lens use.
These statistics make corneal abrasion one of the most common eye problems doctors see. It's common enough to seem routine, yet serious enough to demand proper treatment. The three-day healing timeline for most cases makes it easy to dismiss as a minor injury, but that same three-day window is when infection can take hold if antibiotics aren't used appropriately.
A Note on Living With It
If you're reading this with a freshly scratched cornea, you probably want to know one thing: when will this end?
For most people, significant improvement comes within 24 hours. The intense foreign-body sensation often diminishes first, followed by reduction in light sensitivity. By day two, many people can function relatively normally with mild discomfort. By day three, the majority feel essentially back to normal, though some residual sensitivity may persist for another few days.
During the healing window, there are things you can do. Keep the eye lubricated—artificial tears help, especially during sleep when the eye naturally dries out. Avoid rubbing your eye no matter how much it wants attention. Wear sunglasses to manage light sensitivity. And resist the temptation to check healing progress by pulling down your lower lid and peering at your reflection—you won't be able to see anything useful, and you might introduce bacteria.
If symptoms worsen after the first 24 hours rather than improve, contact your doctor. Increasing pain, spreading redness, worsening vision, or any discharge from the eye could indicate infection requiring more aggressive treatment.
The cornea's remarkable healing ability usually prevails. Within days, the transparent dome at the front of your eye will have rebuilt itself, cell by cell, until no evidence of the scratch remains. You'll blink normally again, barely remembering how much a single scratch once consumed your attention.
At least until the next time you find yourself on the wrong end of a fingernail, a tree branch, or a contact lens worn just a few hours too long.