Dry eye is a condition where your eyes don’t produce enough tears or the tears evaporate too quickly, leaving the surface of your eye unprotected and irritated. It affects roughly 35% of people worldwide, making it one of the most common reasons for an eye doctor visit. Despite the name, dry eye doesn’t always feel “dry.” It can show up as burning, grittiness, blurred vision, or, paradoxically, excessive tearing.
How Your Tear Film Works
Your tears aren’t just saltwater. They form a thin, layered film across the surface of your eye every time you blink. The outermost layer is an oily coating produced by tiny glands along your eyelid margins called meibomian glands. This oil slows evaporation. Beneath it sits the watery (aqueous) layer, which makes up most of the tear film’s volume and comes from the lacrimal glands above each eye. The innermost layer is a thin mucus coating that helps the watery layer spread evenly across the cornea and stick to the eye’s surface.
When any of these layers is disrupted, the tear film breaks down faster than your blink cycle can rebuild it. That leaves patches of exposed cornea, triggering irritation and inflammation.
Two Main Types of Dry Eye
Dry eye falls into two categories, though many people have a mix of both.
Evaporative dry eye is by far the more common form, responsible for over 85% of cases. It happens when the oily outer layer of the tear film is deficient, usually because the meibomian glands in your eyelids are clogged or not functioning properly. Without enough oil, tears evaporate off your eye too quickly.
Aqueous-deficient dry eye accounts for about one in ten cases. Here, the lacrimal glands simply don’t produce enough of the watery component. This type is sometimes linked to autoimmune conditions like Sjögren’s syndrome, which attacks moisture-producing glands throughout the body.
What Dry Eye Feels Like
The symptoms can be surprisingly varied. Most people notice a stinging or burning sensation, especially later in the day. A gritty feeling, as though something is stuck in your eye, is another hallmark. Other common symptoms include:
- Redness and general eye fatigue
- Episodes of blurred or fluctuating vision, particularly during reading or screen use
- Heavy-feeling eyelids
- Sensitivity to light
- A stringy mucus-like discharge
- Difficulty tolerating contact lenses
One of the more confusing symptoms is watery eyes. When the cornea gets too dry, it triggers a reflex that floods the eye with a rush of watery tears. These emergency tears lack the balanced oil and mucus of a healthy tear film, so they don’t solve the underlying problem and tend to spill down your cheeks instead.
Common Risk Factors and Causes
Age is the single biggest risk factor. Tear production naturally declines as you get older, and hormonal changes during menopause make dry eye significantly more common in women over 50. But younger people are increasingly affected too, largely because of screen habits.
When you’re focused on a screen, your blink rate drops dramatically. Normal blinking happens about 14 to 16 times per minute. During screen use, that can fall to just 4 to 6 blinks per minute. Fewer blinks means the tear film isn’t being refreshed, and the blinks that do happen tend to be incomplete, with the upper lid failing to sweep all the way across the cornea. Both factors accelerate tear evaporation.
Several common medications can reduce tear production as a side effect. Antihistamines (the kind you take for allergies), certain antidepressants, blood pressure medications, and decongestants are frequent culprits. If your dry eye symptoms appeared or worsened around the time you started a new medication, that connection is worth raising with your doctor.
Environmental factors matter too. Air conditioning, heating, wind, and low-humidity environments all speed up tear evaporation. Contact lens wear is another well-known contributor, as lenses can disrupt the tear film and reduce oxygen reaching the cornea.
How Dry Eye Is Diagnosed
An eye doctor can usually identify dry eye through a combination of your symptom history and a few simple in-office tests. One classic test involves placing a small strip of filter paper inside your lower eyelid for five minutes to measure how much moisture your eye produces. Without numbing drops, wetting less than 15 mm of the strip suggests dry eye. With numbing drops (which isolate the baseline tear production from the reflex response), less than 5 mm indicates severe dryness, 5 to 10 mm is moderate, and 10 to 15 mm is mild.
Your doctor may also assess how quickly your tear film breaks apart after a blink, using a dye visible under blue light. A rapid breakup time points toward evaporative dry eye and meibomian gland problems.
Treatment Options
For most people, dry eye management starts with over-the-counter artificial tears. These are lubricating eye drops designed to supplement your natural tear film. They come in a wide range of formulations. Thinner, watery drops work well for mild symptoms and can be used frequently throughout the day. Thicker gel-based drops last longer on the eye’s surface but can temporarily blur vision, so many people prefer them at bedtime. If you use artificial tears more than four times a day, preservative-free versions are worth choosing, since the preservatives in bottled drops can irritate the eye with frequent use.
When artificial tears aren’t enough, prescription options target the inflammation that drives chronic dry eye. The most widely prescribed option works by calming the immune response on the eye’s surface, which over time helps restore healthier tear production. These drops typically take several weeks to reach full effect, so they’re not an instant fix.
For evaporative dry eye caused by clogged meibomian glands, treatments focus on getting those glands flowing again. Warm compresses held over closed eyes for 5 to 10 minutes can soften hardened oils in the glands. Gentle lid massage afterward helps express the oil. Your eye doctor may also recommend in-office procedures that apply controlled heat or pressure to the eyelids for a more thorough clearing.
What Happens if Dry Eye Goes Untreated
Mild dry eye is mostly a quality-of-life issue, making reading, driving, and screen work uncomfortable. But chronic, severe dry eye can lead to real damage. Without a stable tear film protecting it, the cornea becomes more vulnerable to infection. Persistent dryness can cause surface abrasions, and in serious cases, corneal ulcers or scarring that affects vision permanently. The inflammation itself also tends to be self-perpetuating: a damaged eye surface triggers more inflammation, which further disrupts tear production, creating a cycle that gets harder to break the longer it continues.
Practical Ways to Reduce Symptoms
The 20-20-20 rule is a simple habit that helps with screen-related dryness: every 20 minutes, look at something 20 feet away for at least 20 seconds. This gives your eyes a break and encourages a normal blink rate. Making a conscious effort to blink fully during screen work also helps, though it feels unnatural at first.
Positioning your screen slightly below eye level can make a difference too. Looking slightly downward narrows the exposed surface area of your eye, which slows evaporation. A desktop humidifier is useful in dry office environments or during winter when heating systems pull moisture from the air. If you sleep with a fan or in air conditioning, directing airflow away from your face overnight can prevent you from waking up with especially dry, irritated eyes.
For people whose dry eye is linked to meibomian gland dysfunction, a nightly routine of warm compresses can be as important as any drop. A clean washcloth soaked in warm water, held against closed lids for several minutes, keeps the oil glands from hardening and clogging over time.