Eye pain has dozens of possible causes, ranging from a long day at a screen to a medical emergency. The most common ones are dry eyes, digital eye strain, minor scratches on the cornea, and allergies. But pain that feels deep, boring, or comes with vision changes can signal something more serious. Where the pain sits, how it feels, and what other symptoms come with it all point toward different explanations.
Dry Eyes and Allergies
Dry eyes are one of the most frequent reasons for everyday eye discomfort. When your eyes don’t produce enough tears, or the tears evaporate too quickly, the surface of the eye loses its protective film. This creates a scratchy, gritty feeling that people often describe as having something stuck in their eye. Air conditioning, heating, wind, and staring at screens without blinking enough all make it worse.
Allergies produce a different kind of discomfort: itching, burning, redness, and watering, often in both eyes at once. Pollen, pet dander, dust mites, and mold are the usual triggers. The key difference is that allergy-related eye pain almost always involves itching, while dry eye pain feels more like friction or sandpaper.
Digital Eye Strain
If your eyes ache after hours on a computer, phone, or tablet, you’re dealing with digital eye strain (sometimes called computer vision syndrome). You blink less frequently when focused on a screen, which dries out your eyes, and your focusing muscles fatigue from holding the same close-range position for too long. The result is a dull ache around or behind the eyes, often paired with headaches and blurred vision.
The American Optometric Association recommends the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds. This gives your focusing muscles a break and encourages blinking. Adjusting screen brightness, reducing glare, and sitting at arm’s length from your monitor also help.
Corneal Scratches and Foreign Objects
A corneal abrasion, or scratch on the clear front surface of your eye, causes sharp pain, tearing, redness, and light sensitivity. It can happen from a fingernail, a piece of dust or sand, a contact lens, or even rubbing your eyes too hard. The pain is often intense relative to the size of the scratch because the cornea is packed with nerve endings.
Minor corneal abrasions typically heal within 24 to 48 hours. Larger scratches take longer and carry a higher risk of infection, especially if something dirty caused the injury. If you feel like something is still in your eye after flushing it with clean water, or if the pain doesn’t improve within a day, you need professional evaluation. A foreign object that’s embedded in the cornea won’t come out on its own.
Contact Lens Problems
Contact lenses are a leading risk factor for corneal ulcers, which are open sores on the cornea caused by infection. Sleeping in your lenses, swimming with them in, or cleaning them with tap water all raise the risk significantly. A parasite called Acanthamoeba, which can survive in undertreated pool water and tap water, is a particularly dangerous cause of corneal ulcers in contact lens wearers.
Symptoms of a corneal ulcer include severe eye pain, a red or bloodshot eye, pus or discharge, watery eyes, and blurred vision. You may also notice a white or gray spot on your eye, though it’s not always visible without magnification. Corneal ulcers can permanently damage your vision if untreated, so any combination of pain, redness, and discharge in a contact lens wearer needs prompt attention.
Infections and Inflammation
Several types of infection and inflammation cause eye pain, and the quality of the pain helps distinguish them.
Keratitis is inflammation of the cornea, usually from bacteria, viruses, or parasites. Bacterial keratitis causes redness, discharge, light sensitivity, and decreased vision. Parasitic keratitis (from Acanthamoeba) tends to develop more slowly, with extreme pain, redness, and light sensitivity building over weeks.
Uveitis is inflammation inside the eye, in the layer just beneath the white of the eye. It produces an achy, deep pain along with light sensitivity and blurred vision. It can be triggered by infections, autoimmune conditions, or sometimes has no identifiable cause.
Scleritis is inflammation of the sclera, the tough white outer wall of the eye. It causes intense, boring pain that worsens when you move your eyes and often radiates into the head as a headache. Scleritis is less common than the others but more serious, and it’s frequently associated with autoimmune diseases like rheumatoid arthritis.
UV Exposure and Photokeratitis
Spending time in bright sun without eye protection, especially around snow, water, or sand, can essentially sunburn your corneas. This condition, called photokeratitis (or snow blindness when caused by reflected UV off snow and ice), is also common among welders who work without proper eye shields. Symptoms include eye pain, redness, tearing, blurry vision, light sensitivity, and a gritty feeling, typically appearing several hours after exposure.
The good news is that photokeratitis is temporary. Symptoms usually last 6 to 24 hours and almost always resolve within 48 hours. It’s preventable with wraparound sunglasses that block UV rays or, for welders, appropriate shielding.
Pain Behind the Eye
Pain that feels like it’s coming from deep behind the eye often isn’t an eye problem at all. Migraines and cluster headaches are the most common culprits.
Cluster headaches are especially striking. They produce burning, sharp, or stabbing pain on one side of the face, centered around the eye and temple. The affected eye often turns red, waters excessively, and the eyelid may droop or swell. These headaches come in clusters, striking one or more times a day for weeks or months, then disappearing. They’re linked to the sudden release of histamine and serotonin near the trigeminal nerve, a major pain pathway in the face, and may involve the hypothalamus, which regulates your body’s internal clock.
Migraines can also cause pain around and behind the eye, usually alongside throbbing pain on one side of the head, nausea, and sensitivity to light and sound. Sinus infections are another source of deep, pressure-like eye pain, typically accompanied by congestion and facial tenderness.
Acute Angle-Closure Glaucoma
This is the eye pain emergency most people have never heard of. Acute angle-closure glaucoma happens when the drainage system inside your eye suddenly blocks, causing pressure to spike rapidly. It causes severe eye pain, a bad headache, nausea or vomiting, blurred vision, halos or colored rings around lights, and eye redness.
Unlike the more common open-angle glaucoma, which develops slowly and painlessly over years, angle-closure glaucoma is sudden and unmistakable. It can permanently damage your optic nerve within hours if untreated. If you experience severe eye pain with nausea, vomiting, or halos around lights, treat it as an emergency.
When Eye Pain Is an Emergency
Most eye pain resolves on its own or with simple measures like rest, lubricating drops, or avoiding triggers. But certain combinations of symptoms require immediate medical attention:
- Severe pain with headache, fever, or light sensitivity
- Sudden vision changes
- Nausea or vomiting alongside eye pain
- Chemical splash or embedded foreign object
- Halos around lights
- Swelling in or around the eye
- Inability to move the eye or keep it open
- Blood or pus coming from the eye
Any of these warrants a call to an ophthalmologist or a trip to the emergency room. Eye pain that’s mild, comes and goes, and isn’t paired with vision changes is far less likely to be dangerous, but persistent discomfort lasting more than a couple of days is still worth getting checked.