Burning eyes are most often caused by dryness on the surface of the eye, but allergies, infections, eyelid problems, environmental irritants, and even certain medications can trigger the same sensation. The feeling ranges from a mild sting to persistent, distracting heat, and understanding the specific cause is the fastest way to find relief.
Dry Eyes: The Most Common Cause
Your eyes are covered by a thin tear film that keeps the surface lubricated, nourished, and protected. When that film evaporates too quickly or your eyes don’t produce enough of it, the surface dries out and the salt concentration in your remaining tears spikes. This hyperosmolarity, as researchers call it, can reach levels high enough to trigger an inflammatory response on the corneal surface. That inflammation stimulates the tiny nerve endings in your cornea, producing the burning or stinging you feel. Even the cooling effect of tears evaporating off the eye can activate specialized nerve fibers that register dryness and irritation.
Dry eye disease affects somewhere between 5% and 50% of the population depending on the region and how it’s measured, making it extremely common. Risk factors include aging, spending long hours at screens (which reduces your blink rate), low-humidity environments, and contact lens wear.
Blocked Oil Glands in the Eyelids
Running along the edges of your upper and lower eyelids are dozens of tiny oil-producing glands called meibomian glands. They secrete an oily layer that sits on top of your tear film and slows evaporation. When these glands become clogged, a condition known as meibomian gland dysfunction (MGD), the oil can’t reach the surface. Your tears evaporate faster, and the result is the same dry, burning sensation.
MGD is one of the most common causes of dry eye syndrome. Symptoms include itching, burning, and a gritty feeling, especially later in the day. Warm compresses held over closed eyelids for several minutes can soften the blocked oil and help restore normal flow. Gentle eyelid massage afterward encourages the glands to release their contents.
Allergies and Histamine Release
If your eyes burn and itch at the same time, especially during pollen season or around pet dander, an allergic reaction is a likely culprit. When an allergen lands on the surface of your eye, immune cells in the tissue release histamine along with other inflammatory compounds. These chemicals dilate blood vessels (causing redness), increase fluid leakage (causing watering and swelling), and directly irritate nerve endings (causing burning and itching).
Allergic conjunctivitis tends to affect both eyes simultaneously and often comes with a clear, watery discharge, sneezing, and nasal congestion. Over-the-counter antihistamine eye drops can calm the reaction, and avoiding the trigger, when possible, prevents it from recurring.
Viral and Bacterial Infections
Conjunctivitis, commonly called pink eye, frequently causes burning. The type of discharge helps distinguish viral from bacterial infections. Viral conjunctivitis typically comes on suddenly with a foreign body sensation, burning, light sensitivity, and a watery discharge. Bacterial conjunctivitis shares many of those symptoms but produces a thicker, yellowish or greenish discharge that often crusts the eyelids shut overnight.
One useful clue: viral conjunctivitis often causes a tender, swollen lymph node just in front of the ear on the affected side. Viral cases usually resolve on their own within one to three weeks, while bacterial cases may need antibiotic drops to clear up faster and reduce the risk of spreading.
Environmental and Chemical Irritants
Smoke, smog, chlorinated pool water, dust, and strong fumes from cleaning products can all irritate the eye’s surface and provoke burning. Cigarette smoke is a particularly common offender because it contains hundreds of irritating compounds that destabilize the tear film.
More serious chemical exposures deserve special attention. Alkaline substances like ammonia, bleach, lime, and lye are responsible for roughly 80% of severe chemical eye burns. Ammonia can penetrate the eye in under three minutes, and any substance with a pH above 11.5 can cause significant corneal damage. Acidic chemicals like sulfuric acid (found in car batteries) generally cause more limited surface damage because the cornea can partially neutralize low pH. The exception is hydrofluoric acid, which dissolves cell membranes and penetrates deeply, similar to alkali burns. If any chemical splashes into your eye, flushing with clean water or saline for at least 15 to 20 minutes is the single most important first step.
Medications That Dry Out Your Eyes
A surprising number of common medications list dry eyes or burning as a side effect. These drugs reduce tear production or change the composition of your tear film, leaving the surface vulnerable.
- Antihistamines (oral allergy pills) block histamine throughout the body, including in the glands that produce tears.
- Antidepressants, particularly older tricyclics and SSRIs, can reduce tear output and cause persistent dryness.
- Beta-blockers used for high blood pressure are linked to dry eye syndrome and corneal surface damage.
- Isotretinoin (Accutane), used for severe acne, disrupts meibomian gland function and is well known for causing dry, burning eyes.
- Antipsychotics and mood stabilizers like lithium can contribute to dryness.
- NSAIDs like ibuprofen, when used long-term, have been associated with dry eye symptoms.
If you started a new medication and noticed your eyes burning shortly after, the timing may not be a coincidence. Preservative-free artificial tears can help bridge the gap while you discuss alternatives with your prescriber.
The Eye Drops Themselves Can Be the Problem
This is one detail many people miss: the very eye drops you’re using for relief may be making the burning worse. The most widely used preservative in eye drops is benzalkonium chloride, or BAK. Studies have consistently shown it’s toxic to the cells on the eye’s surface, and in people who use preserved drops regularly, it can cause redness, stinging, burning, and additional dryness.
A large European study involving nearly 10,000 patients found that every recorded symptom and sign of eye irritation was significantly more frequent in people using preserved eye drops compared to those using preservative-free formulations. If you’re applying drops more than a few times a day or using them long-term (as with glaucoma medications), switching to preservative-free versions can make a noticeable difference.
How Doctors Evaluate Burning Eyes
If burning persists, an eye care provider can run a few straightforward tests to narrow down the cause. The Schirmer test measures tear production by placing a small strip of filter paper inside the lower eyelid for five minutes. A wet length greater than 15 mm is considered normal. Between 5 and 10 mm indicates moderate dryness, and below 5 mm points to a significant tear deficiency. A tear breakup time test evaluates how quickly the tear film destabilizes after a blink; a short breakup time is a reliable indicator that hyperosmolarity is driving the irritation.
These tests are painless and take just a few minutes. Combined with a close look at your eyelids and tear film under a slit lamp, they give a clear picture of whether dryness, gland dysfunction, inflammation, or infection is behind the burning.
Signs That Need Prompt Attention
Most causes of burning eyes are uncomfortable but not dangerous. However, certain combinations of symptoms signal something more serious. Seek care promptly if burning eyes are accompanied by any loss of vision, sensitivity to light, a rash on your face or body, fever, or a severe headache. These can indicate conditions like herpes simplex infection of the eye, shingles involving the ophthalmic nerve, or a chemical injury that has penetrated deeper layers of the eye. A sudden chemical splash always warrants immediate flushing followed by urgent evaluation, even if the burning seems to improve.