Eye pain has dozens of possible causes, ranging from something as minor as a dry patch on the surface of your eye to something as urgent as a sudden spike in pressure inside the eyeball. The type of pain you feel, where exactly you feel it, and how quickly it came on are the best clues to what’s going on. Most eye pain falls into two broad categories: surface pain (a scratchy, burning, or stinging feeling on the front of the eye) and deep pain (an ache or throb behind or within the eye itself).
Surface Pain: Scratchy, Gritty, or Stinging
The most common reasons for pain on the surface of your eye involve the cornea, the clear outer layer that covers your iris and pupil. A tiny scratch on the cornea, called a corneal abrasion, causes sharp stinging that usually starts suddenly. You’ll likely tear up, feel like something is stuck in your eye, and find bright lights uncomfortable. If a speck of dust, metal, or debris actually is lodged on your eye, the symptoms are similar but tend to get worse rather than better over time. When a foreign body stays on the cornea for more than 24 hours, white blood cells can migrate into the area and trigger inflammation, making the pain and light sensitivity noticeably worse.
Conjunctivitis, or pink eye, produces a different flavor of discomfort. It’s more of a burning or itchy irritation across the white of the eye and inner eyelids, usually with redness and discharge. Bacterial forms tend to produce thick, yellowish discharge, while viral and allergic forms lean more toward watery eyes and itching. The pain is usually mild compared to a corneal scratch.
Dry Eye: More Painful Than It Sounds
Chronic dry eye is one of the most underestimated causes of eye pain. It can produce a surprisingly wide range of sensations: throbbing, aching, sharp stabbing, burning, and even what patients describe as electric-shock pain. Research using detailed pain questionnaires has found that dry eye involves continuous, intermittent, and nerve-related pain types all at once. People also commonly report eye fatigue and a heavy-eyelid feeling as part of their discomfort.
One common subtype involves the meibomian glands, tiny oil-producing glands along your eyelid margins. When these glands get clogged, your tear film evaporates too quickly, and the resulting dryness combines with low-grade eyelid inflammation to create persistent soreness. Dry eye pain often worsens with screen use, air conditioning, wind, or contact lens wear.
Deep Eye Pain: Aching or Throbbing
Pain that feels like it’s coming from behind or deep within the eye points to a different set of causes. Scleritis, an inflammation of the tough white outer wall of the eye, produces a boring, deep ache along with tenderness when you press gently on the eyeball through your closed lid. It’s relatively rare and often linked to autoimmune conditions like rheumatoid arthritis.
Uveitis, inflammation of the middle layer of the eye, causes a dull ache along with redness, light sensitivity, and sometimes blurry vision. A doctor can only confirm it by looking for inflammatory cells floating inside the eye using a specialized microscope called a slit lamp.
Optic neuritis, inflammation of the nerve that connects your eye to your brain, has a distinctive signature: pain that gets worse when you move your eye. About 90% of people with optic neuritis notice this pain-with-eye-movement pattern, and it typically develops over hours to days alongside worsening vision in one eye. Optic neuritis can be an early sign of multiple sclerosis, so it always warrants a thorough workup, usually including an MRI of the brain and eye sockets.
Pain That Isn’t Coming From the Eye Itself
Sometimes what feels like eye pain actually originates somewhere else entirely. Sinus infections can cause pressure and aching around and behind the eyes, especially over the forehead and between the eyebrows. Migraines are another major source. Research from the HEADS registry has found that a significant subset of people experiencing recurrent facial and sinus-area pain, including pain over and behind the eyes, actually have a migraine-driven process rather than a sinus infection. The giveaway is that these episodes come with symptoms you wouldn’t expect from sinuses alone, like sensitivity to light, dizziness, or nausea.
Cluster headaches deserve a mention because they cause some of the most intense eye pain people experience. The pain is typically one-sided, centered in or around one eye, and accompanied by tearing, a droopy eyelid, or a stuffy nostril on the same side. Episodes last 15 minutes to 3 hours and tend to recur at the same time of day.
Acute Angle-Closure Glaucoma
This is the eye pain emergency most people haven’t heard of. It happens when the drainage system inside your eye suddenly gets blocked, causing pressure to skyrocket from a normal range of 10 to 21 mmHg up to 60 or even 80 mmHg. The pain is intense and comes on quickly, usually in one eye. You may also notice nausea or vomiting, halos around lights, a red eye, and vision that goes blurry or hazy rapidly. The affected pupil often looks fixed and slightly dilated, and the cornea can appear cloudy.
This is a true emergency. Without treatment to lower the pressure, the optic nerve can sustain permanent damage within hours. If you’re experiencing severe eye pain with blurry vision and nausea, go to an emergency room immediately.
Serious Infections Inside the Eye
Keratitis is an infection of the cornea, most commonly seen in contact lens wearers. It causes pain, redness, light sensitivity, and sometimes a visible white spot on the cornea. In rare cases, a corneal infection can spread deeper into the eye, a condition called endophthalmitis. Pain was reported in about 73% of endophthalmitis cases in one study, along with significant vision loss and light sensitivity. Risk factors for this progression include pre-existing dry eye, recent eye surgery or trauma, immune suppression, and steroid use (either eye drops or systemic).
How Doctors Figure Out the Cause
An eye pain evaluation usually starts simply. A visual acuity test using a standard eye chart establishes whether your vision is affected. A penlight test checks whether shining light into your eye triggers discomfort, which can point to inflammation of the cornea or the inner eye. If a scratch or foreign body is suspected, fluorescein dye is applied to the eye surface. Under a blue or ultraviolet light, any breaks in the corneal surface glow bright green.
For deeper problems, a slit lamp exam lets the doctor see inflammatory cells inside the eye. If acute glaucoma is a concern, a tonometry test measures the pressure inside your eye. And for suspected optic neuritis, a swinging flashlight test checks whether one pupil responds abnormally to light, which can reveal nerve damage even before an MRI is ordered.
Red Flags That Need Same-Day Attention
Five specific features signal that eye pain could be sight-threatening and needs specialist evaluation the same day:
- Moderate to severe pain that isn’t improving or is getting worse
- Light sensitivity significant enough to make you squint or avoid light
- Marked redness concentrated around the colored part of the eye rather than just the whites
- Reduced vision in the affected eye, even if subtle
- Foreign body or penetrating injury to the eye
Any sudden loss of vision, with or without pain, is a medical emergency. The faster you’re diagnosed and treated, the better your chances of preserving your sight. If your eye pain is mild, came on gradually, and your vision is normal, it’s reasonable to monitor it for a day or two. But if the pain is worsening, your vision is changing, or you have any of the red flags above, don’t wait.