Eye pain has dozens of possible causes, ranging from a dry eye surface to a pressure spike inside the eyeball. The type of pain you feel, where exactly it seems to come from, and what other symptoms show up alongside it are the best clues to what’s going on. Most eye pain falls into two broad categories: surface pain (a stinging, burning, or gritty feeling on the front of the eye) and deep pain (an aching or throbbing sensation behind or inside the eye).
How Your Eye Detects Pain
The cornea and the tissues surrounding your eye are among the most sensitive structures in your body. They’re packed with pain-sensing nerve fibers that belong to the ophthalmic branch of the trigeminal nerve, the largest cranial nerve and the one responsible for all sensation across your forehead, eyes, and upper face. When something irritates or damages the eye’s surface, these fibers fire rapidly and send signals through the trigeminal system to the brain. That’s why even a tiny eyelash or speck of dust can produce intense, disproportionate pain.
This same nerve network is also why eye pain sometimes originates from problems that have nothing to do with the eye itself. Sinus infections, cluster headaches, and certain neurological conditions can all produce pain that feels like it’s coming from your eye, because the pain signals travel along overlapping branches of the trigeminal nerve.
Surface Causes: Corneal and Conjunctival Problems
The most common reason for a sharp, stinging pain on the surface of your eye is some form of damage or irritation to the cornea, the clear dome at the front of the eyeball. A corneal abrasion (a scratch from a fingernail, contact lens, or foreign particle) typically causes immediate tearing, redness, and a persistent feeling that something is stuck in your eye. Most minor scratches heal within a day or two.
When the cornea becomes inflamed rather than just scratched, the condition is called keratitis. It can be triggered by wearing contact lenses too long, getting a foreign body in the eye, or by an infection from bacteria, viruses, fungi, or parasites. Extended-wear soft contact lenses carry the highest risk: the rate of microbial keratitis in extended-wear users is roughly 13 to 21 per 10,000 per year, compared with about 2 per 10,000 for rigid lens users. Symptoms include redness, blurred vision, light sensitivity, excess tearing, and difficulty opening the eyelid. With prompt treatment, mild to moderate cases typically resolve without lasting vision loss.
Conjunctivitis (pink eye) is another frequent surface-level cause. Viral and bacterial forms produce a gritty, burning discomfort along with discharge and redness. Allergic conjunctivitis tends to cause more itching than true pain.
Dry Eye and Digital Strain
Chronic surface-level eye pain is often tied to dry eye, a condition in which the tear film doesn’t adequately protect the cornea. The prevalence of ocular surface pain ranges from 5% to 50% depending on the population studied, and signs of tear dysfunction are even more widespread, showing up in as many as 75% of people in certain groups. Extended screen time makes it worse because you blink less when staring at a monitor, which lets the tear film evaporate faster. The result is a burning, sandy sensation that tends to worsen as the day goes on, especially in air-conditioned or heated rooms.
Deep Eye Pain: Glaucoma and Inflammation
Pain that feels like it’s coming from inside or behind the eye usually points to a different set of causes. The most urgent is acute angle-closure glaucoma, a sudden spike in pressure inside the eyeball. Normal eye pressure sits between 10 and 21 mmHg. During an acute attack, pressure can rocket to 60 or even 80 mmHg. This produces severe, one-sided eye pain or headache along with blurred vision, rainbow-colored halos around lights, nausea, and vomiting. It’s a medical emergency because the optic nerve can suffer permanent damage within hours.
Uveitis, inflammation of the middle layer of the eye, is another common source of deep aching pain. The front-of-eye form (anterior uveitis or iritis) causes sharp pain, redness, and intense light sensitivity. That light sensitivity happens because the inflamed tissue is densely wired with the same trigeminal pain fibers that cover the cornea. Light entering the eye causes the inflamed iris to contract, directly triggering those pain fibers. Posterior uveitis, which affects the back of the eye, is less likely to cause noticeable pain because the retina itself has no pain receptors.
Optic Neuritis
Optic neuritis is inflammation of the optic nerve, the cable that carries visual information from the eye to the brain. It typically strikes adults between 18 and 50, with an average onset around age 36. The hallmark symptom is pain that worsens when you move your eyes, followed by a decline in vision over days. Moving your eyes pulls on the inflamed portion of the nerve, and since eye movements are normally completely unfelt, any sensation during movement is diagnostically significant. About 8% of cases involve inflammation in the portion of the nerve that sits inside the skull, beyond its mobile segment, so those patients don’t experience pain with eye movement at all. Colors often look washed out or darker through the affected eye.
Infections Behind the Eye
Infections in the tissues surrounding the eye come in two forms, and telling them apart matters. Preseptal cellulitis affects only the eyelid and skin in front of a thin membrane called the orbital septum. It causes swelling, redness, and tenderness, but eye movement stays normal, vision is unaffected, and the eye doesn’t bulge forward.
Orbital cellulitis is the deeper, more dangerous version. The infection spreads behind the septum into the fat and muscles that surround the eyeball. The eye begins to protrude, movement becomes painful and restricted, and vision can deteriorate. In severe cases, the swelling compresses the optic nerve, reducing color vision and causing pupil abnormalities. Orbital cellulitis requires urgent treatment because it can threaten both sight and, in rare cases, life.
Headaches That Feel Like Eye Pain
Not all pain felt “in the eye” originates there. Cluster headaches produce excruciating pain centered around or behind one eye, often accompanied by tearing, nasal congestion, and a drooping eyelid on the same side. Individual attacks last between 15 minutes and 3 hours and can recur up to eight times a day during active periods. Migraines can also concentrate pain around the eye, sometimes with visual aura beforehand. Sinus headaches create a pressure-like ache behind the eyes and across the forehead that worsens when you bend forward.
The key distinction is that headache-related eye pain rarely comes with visible changes to the eye itself. If your eye looks normal in the mirror (no redness, no swelling, normal pupil size), the pain is more likely referred from a headache disorder or sinus issue than from an eye disease.
Symptoms That Need Same-Day Attention
A large triage study identified several features that warrant emergency eye care the same day they appear. These include:
- Sudden vision loss in one eye
- Eye pain in one eye, especially with redness or light sensitivity
- A dark curtain or shadow across part of your vision
- Eye pain or redness if you wear contact lenses
- Any eye injury or trauma
- Swelling around one eye
- Known uveitis with a flare of symptoms
- Rapid change in visual sharpness
By contrast, symptoms that have been stable for more than four weeks, bilateral itchiness, a small eyelid bump, or mild bilateral blurriness can generally wait for a routine appointment with an optometrist or GP. The pattern that should raise your concern most is one-sided pain combined with vision changes, because that combination overlaps with nearly every serious eye condition, from acute glaucoma to orbital cellulitis to optic neuritis.