A corneal abrasion is a scratch on the clear front surface of your eye. It affects only the outermost layer of the cornea, called the epithelium, and most small abrasions heal within one to three days. Despite being superficial, these scratches can be surprisingly painful and temporarily blur your vision.
What the Cornea Is and Why Scratches Hurt
The cornea is the transparent dome covering the colored part of your eye. It has five distinct layers, and an abrasion damages only the first: the epithelium, a thin sheet of cells that regenerates quickly. As long as the scratch stays within this top layer and doesn’t penetrate the membrane beneath it, it’s classified as an abrasion rather than a deeper laceration.
What makes even a tiny scratch so painful is that the cornea is one of the most densely nerve-packed tissues in your body. A small defect triggers pain signals out of proportion to the size of the injury. The cornea also plays a major role in focusing light, so any disruption to its smooth surface can immediately affect how clearly you see.
Common Causes
Anything that physically contacts the surface of the eye can cause an abrasion. The most common culprits are fingernails (especially from babies or during sports), dust or sand particles, tree branches, and contact lenses worn too long or removed carelessly. Makeup brushes, paper edges, and pet claws are frequent offenders too. Sometimes you won’t even realize when the scratch happened, only that your eye suddenly hurts.
Symptoms to Recognize
The hallmark of a corneal abrasion is the persistent feeling that something is stuck in your eye, even after you’ve flushed it with water. Other typical symptoms include:
- Eye pain that worsens with blinking
- Watery eyes as your tear glands overreact to the injury
- Sensitivity to light, which can make it hard to keep the affected eye open
- Blurred vision in the injured eye
- Redness and swelling of the eye or eyelid
Light sensitivity happens because the exposed nerve endings react to the iris contracting, which causes a deep aching pain. This is different from the sharp, gritty surface pain you feel when blinking.
How It’s Diagnosed
An eye care provider can confirm an abrasion in minutes using a simple, painless dye test. A small strip of paper containing orange fluorescein dye is touched to the surface of your eye, or the dye is applied as a drop (often combined with a numbing agent). You blink a few times to spread the dye across the tear film. Under a blue light, any break in the corneal surface glows bright green, revealing the exact size, shape, and location of the scratch. The pattern of staining helps distinguish a simple abrasion from other problems like an infection or a foreign body still embedded in the cornea.
How Corneal Abrasions Heal
The corneal epithelium regenerates faster than almost any other tissue in the body. Cells at the edges of the wound begin sliding inward at roughly 0.06 millimeters per hour, gradually closing the gap. Research shows this healing process speeds up after about four hours, then begins to slow after ten hours as the initial burst of cell migration tapers off. For a small, uncomplicated scratch, this means noticeable improvement within 24 hours and full closure within one to three days.
Larger abrasions, or those in the center of the cornea directly over the pupil, can take longer. Contact lens-related abrasions also tend to heal more slowly because they carry a higher risk of bacterial involvement, which complicates recovery.
Treatment and Pain Relief
Most corneal abrasions are treated with antibiotic eye drops or ointment to prevent infection while the surface heals. These are typically applied four times a day for three to five days. Once you no longer feel any grittiness or pain, the frequency is reduced and then stopped. If you wear contact lenses, your provider will likely choose a different class of antibiotic that covers the types of bacteria more common in lens wearers.
For pain, over-the-counter options like ibuprofen or acetaminophen are the first line. Anti-inflammatory eye drops applied directly to the eye have shown the most consistent pain relief in clinical studies. Drops that temporarily paralyze the focusing muscle of the eye (to stop painful spasms) are sometimes prescribed, though research suggests they don’t reduce pain as reliably as anti-inflammatory drops do.
One practice that has largely fallen out of favor is patching the injured eye. A major review found no significant difference in healing time, pain at 24 hours, or symptoms like tearing and light sensitivity between people who wore a patch and those who didn’t. Current guidelines from NICE in the UK don’t include patching as a recommended treatment for simple abrasions. In some cases a patch may still be used briefly after numbing drops, when the blink reflex is temporarily impaired, but routine patching is no longer standard care.
What Not to Do
Rubbing your eye is the biggest mistake you can make with a suspected abrasion. It can enlarge the scratch or push a foreign particle deeper. Avoid using over-the-counter redness-relief drops, which can sting and don’t address the actual injury. Don’t wear contact lenses until the abrasion is fully healed and your provider gives the green light, even if the eye feels better after a day or two. Putting contacts back in too soon traps bacteria against the healing surface.
When Abrasions Become Complicated
The main risks from a corneal abrasion are infection and recurrent erosion. Infection occurs when bacteria enter through the break in the epithelium. Warning signs include worsening pain after the first day, increasing redness, discharge, or a white spot on the cornea. Left untreated, a corneal infection can progress to an ulcer, which threatens vision.
Recurrent corneal erosion is a condition where the healed epithelium fails to anchor properly and tears open again, sometimes weeks or months after the original scratch. It often strikes first thing in the morning, when the eyelid sticks to the cornea during sleep and pulls the loosely attached cells away on opening. You’ll feel a sudden sharp pain, tearing, and light sensitivity that echoes the original injury. About 1% of the population in urban studies experiences this condition in a given year, and having one episode raises the risk of future ones. Repeated erosions can leave a slight haze on the cornea over time.
If your abrasion was caused by plant matter (a tree branch or thorn), the risk of both infection and recurrent erosion is higher than with a clean, mechanical scratch. These injuries deserve closer follow-up even if they initially seem minor.