Dry eyes feel like stinging, burning, or a gritty sensation, as if something is stuck in your eye. The condition typically affects both eyes at once and can range from a mild annoyance to something that interferes with reading, driving, and wearing contact lenses. If those symptoms sound familiar, here’s how to tell what’s going on and what might be causing it.
The Most Common Symptoms
Dry eye doesn’t always feel “dry” in the way you’d expect. The hallmark symptoms include a scratchy or burning sensation, eye redness, and sensitivity to light. You might notice stringy mucus collecting in the corners of your eyes, especially in the morning. Blurred vision that comes and goes, particularly during reading or screen work, is another telltale sign.
One of the most counterintuitive symptoms is watery eyes. When your eye surface gets too dry, it triggers a reflex that floods your eyes with tears. These emergency tears don’t have the right composition to actually protect your eye surface, so the cycle of dryness and flooding continues. If your eyes water constantly but still feel irritated, dry eye is a likely explanation.
You may also notice that nighttime driving has become harder, with more glare and halos around lights. Contact lens wearers often feel it first, finding their lenses increasingly uncomfortable by the end of the day.
What’s Actually Happening in Your Eyes
Your tear film has three layers: an oily outer layer that prevents evaporation, a watery middle layer, and a mucus layer that helps tears stick to the eye surface. Dry eye happens when one or more of these layers breaks down, and the type matters because it affects what helps.
About 50% of people with dry eye have the evaporative type, where the oily outer layer is deficient. This is usually caused by dysfunction in the tiny oil glands lining your eyelids. Without enough oil, tears evaporate too quickly, even if you’re producing a normal volume. Another 14% have the aqueous deficient type, meaning the lacrimal glands simply don’t produce enough of the watery component. The remaining 36% have a mix of both.
This distinction explains why basic eye drops help some people but barely touch the problem for others. If your issue is evaporation rather than production, you need a different approach.
Screen Time and Blink Rate
You normally blink about 15 times per minute. When you’re staring at a screen, reading, or doing any focused close-up work, that rate drops by roughly half. Each blink spreads a fresh layer of tears across your eye, so fewer blinks means your tear film breaks down faster between refreshes. If your symptoms are worst at the end of a workday spent at a computer, this is probably a major factor.
Air conditioning, heating, ceiling fans, and low-humidity environments compound the effect. A dry office with forced air blowing while you stare at a monitor for eight hours is essentially engineered to cause dry eyes.
Medications That Cause Dry Eyes
Among the top 100 best-selling drugs in the U.S., 22 can cause dry eye as a side effect. In older adults, an estimated 62% of dry eye cases can be traced back to medications. The list is long: antihistamines, antidepressants, blood pressure medications, diuretics, anti-anxiety drugs, and common pain relievers like ibuprofen.
Many of these drugs share a mechanism. They block a type of cellular receptor that plays a role in tear, mucus, and oil secretion. Some medications, including ibuprofen and certain heart rhythm drugs, are actually secreted into your tears and can form tiny crystals on the eye surface, causing direct irritation.
Glaucoma eye drops deserve special mention. Up to 47% of patients using them experience burning and dry eye symptoms, largely because of a preservative in the drops that is toxic to surface cells and triggers inflammation. If you use prescription eye drops and your eyes feel worse, not better, that preservative may be the reason.
Autoimmune Dry Eye Feels Different
When dry eyes are severe, don’t respond to typical remedies, and come with a dry mouth, joint pain, or fatigue, an autoimmune condition called Sjögren’s syndrome may be involved. In Sjögren’s, the immune system attacks moisture-producing glands throughout the body, not just in the eyes. People with this condition often notice they need water to swallow dry food, or that their eyes feel inflamed rather than just gritty.
Other signs that point toward Sjögren’s include swollen glands near the jaw, Raynaud’s phenomenon (fingers turning white or blue in the cold), skin rashes, and numbness or tingling in the hands and feet. Diagnosis involves a blood test for specific antibodies and sometimes a biopsy of the salivary glands. If your dry eyes came on alongside widespread dryness and fatigue, it’s worth investigating.
A Quick Self-Assessment
Eye doctors use a standardized questionnaire called the Ocular Surface Disease Index (OSDI) to gauge severity. It scores from 0 to 100 based on how often you experience symptoms, how much they affect daily activities, and how sensitive your eyes are to environmental triggers. A score under 13 is considered normal. Scores of 13 to 22 indicate mild dry eye, 23 to 32 is moderate, and 33 or above is severe.
You can find the OSDI online and score yourself in a few minutes. It won’t replace a professional exam, but it gives you a useful baseline and a way to track whether your symptoms are getting better or worse over time.
What Happens at an Eye Exam
If you see an eye doctor for dry eye, they’ll likely run two key tests. The first measures tear production: a small strip of filter paper is placed under your lower eyelid for five minutes. More than 10 millimeters of moisture on the strip is normal. Less than that suggests your eyes aren’t producing enough tears.
The second test measures how quickly your tear film breaks apart after a blink. A tiny amount of dye is placed on the eye, and the doctor watches under a special light. If the tear film breaks up in five seconds or less, that points to evaporative dry eye. A stable tear film holds together for at least ten seconds. Together, these tests help determine which type of dry eye you have and guide treatment.
Your doctor will also look at the oil glands in your eyelids and check for signs of inflammation on the eye surface. If an autoimmune cause is suspected, blood work may follow.
Patterns That Point to Dry Eye
Not every irritated eye is dry eye. Allergies cause itching more than burning, and the itching tends to be seasonal or tied to specific triggers like pet dander. Infections typically affect one eye first and produce colored discharge rather than clear, stringy mucus. Dry eye, by contrast, affects both eyes, feels worse with screen use and wind exposure, and improves temporarily with artificial tears.
Pay attention to timing. Symptoms that build throughout the day and peak in the evening strongly suggest dry eye, especially if your mornings start relatively comfortable. Symptoms that are worst upon waking, with crusty or stuck-together eyelids, may point to a related eyelid condition. Symptoms that fluctuate with seasons, come with sneezing, or respond to allergy medication are more likely allergic.
If your vision blurs when you’re tired or after prolonged reading but clears when you blink a few times, that’s a classic dry eye pattern. The tear film is literally breaking down between blinks, distorting the light entering your eye. Persistent blurred vision that doesn’t clear with blinking has a different cause.