Your eye feels dry because something has disrupted the thin layer of moisture that normally coats the surface of your eye. This tear film is surprisingly complex, with three distinct layers that work together to keep your eyes lubricated, nourished, and protected. When any one of those layers falls short, you get that gritty, stinging, or scratchy sensation that brought you here. The cause could be anything from staring at a screen too long to a medication you’re taking, and pinpointing it is the first step toward relief.
How Your Tear Film Works
Your tears aren’t just saltwater. They’re a three-layer system, and each layer has a specific job.
The outermost layer is an oily film produced by tiny glands along your eyelid margins. This oil acts as a barrier between your tears and the air, slowing evaporation and creating a smooth optical surface for clear vision. Beneath that sits the watery layer, which makes up the bulk of your tears. It carries proteins, vitamins, and immune molecules that nourish and protect your cornea, which has no blood vessels of its own. The innermost layer is a thin mucus coating that helps the watery layer spread evenly across your eye and stick to the surface instead of sliding off.
When any of these layers is deficient, the whole system breaks down. Too little oil means your tears evaporate too quickly. Too little water means there’s not enough moisture to go around. Too little mucus means whatever tears you produce can’t spread properly. Most dry eye falls into the first category: excess evaporation caused by problems with those oil-producing glands.
Screen Time and Blinking
If your eyes feel dry after hours at a computer, your blink rate is almost certainly the culprit. When you’re relaxed, you blink about 22 times per minute. When you’re reading a book, that drops to around 10. When you’re staring at a screen, it plummets to roughly 7 blinks per minute.
Each blink spreads a fresh coat of oil and moisture across your eye. When you blink less than a third as often as normal, your tear film dries out between blinks, leaving patches of your cornea exposed. On top of that, screen use often involves incomplete blinks, where your upper eyelid doesn’t travel all the way down. That means even the blinks you do make aren’t fully refreshing the tear film. The fix is deceptively simple: make a conscious effort to blink fully and frequently, especially during focused tasks. Some people set a reminder every 20 minutes to look away from the screen and blink slowly several times.
Indoor Air and Environment
Dry air accelerates tear evaporation regardless of how well your tear glands are functioning. Air conditioning, forced-air heating, ceiling fans blowing directly on your face, and airplane cabins all strip moisture from your eyes. Indoor humidity levels of about 45% or more are best for your eyes. In winter, many heated homes drop well below that.
A humidifier in the room where you spend the most time can make a noticeable difference. Positioning your computer screen below eye level also helps, because looking slightly downward means your eyelids cover more of your eye’s surface, reducing the exposed area where tears can evaporate.
Medications That Cause Dryness
A surprising number of common medications reduce tear production as a side effect. In older adults, an estimated 62% of dry eye cases can be traced back to systemic medications. The list is long: antihistamines (including over-the-counter allergy pills), antidepressants, blood pressure medications, diuretics, anti-anxiety drugs, and even common pain relievers like NSAIDs.
Antihistamines are particularly well-known offenders because their entire mechanism involves drying up secretions, and your tear glands don’t get an exemption. If your eyes started feeling dry around the same time you began a new medication, that connection is worth exploring. Don’t stop a prescribed medication on your own, but bring it up at your next appointment so your provider can weigh alternatives.
Meibomian Gland Dysfunction
The oil-producing glands along your eyelid margins, called meibomian glands, are the single most common source of chronic dry eye. These glands can become clogged when the oil they produce thickens or when the duct openings harden and narrow. This happens naturally with aging, hormonal changes (particularly declining androgen levels), and even habitual use of eyeliner applied to the inner lid margin, which can physically block the gland openings and cause progressive damage over time.
When these glands can’t secrete enough oil, your tears evaporate far too quickly no matter how much watery fluid your eyes produce. You might notice that your eyes feel worse in windy conditions or air-conditioned rooms, because there’s no protective oil barrier to slow evaporation. Warm compresses applied to closed eyelids for 5 to 10 minutes can soften hardened oil and help the glands express more freely. Gently massaging your eyelids afterward pushes the loosened oil out of the gland openings.
Autoimmune and Systemic Causes
Persistent, severe dry eye that doesn’t respond to typical remedies can sometimes signal an underlying autoimmune condition. Sjögren’s syndrome is the most well-known example. In this disease, the immune system mistakenly attacks the glands that produce moisture in the eyes and mouth, leading to significant dryness in both. Sjögren’s is more common in people who already have rheumatoid arthritis or lupus.
If your dry eyes are accompanied by a persistently dry mouth, joint pain, or fatigue, those symptoms together paint a picture worth investigating. A blood test can check for the specific antibodies associated with Sjögren’s. Other systemic conditions like thyroid disease and diabetes can also contribute to dry eye through different mechanisms, including inflammation and nerve damage that disrupts tear production signals.
What You Can Do at Home
Artificial tears are the first line of defense for most people. These over-the-counter drops supplement your natural tear film and provide immediate, if temporary, relief. If you find yourself reaching for them more than four times a day, switch to preservative-free formulas. The preservatives in standard drops can irritate the eye’s surface with frequent use, actually worsening the problem they’re meant to solve.
Omega-3 fatty acids may improve tear quality over time by supporting healthier oil production from the meibomian glands. Clinical trials have tested daily doses in the range of 1,000 to 2,000 mg of EPA and 500 to 1,000 mg of DHA (the two key omega-3 components found in fish oil). Results across studies have been mixed, but some patients with meibomian gland dysfunction see meaningful improvement after several months of consistent supplementation.
Other practical steps that help: wearing wraparound sunglasses outdoors to block wind, taking breaks from contact lenses when your eyes feel irritated, and staying well hydrated. Dehydration won’t cause dry eye on its own, but it won’t help a marginal tear film either.
When Drops Aren’t Enough
If over-the-counter drops and lifestyle changes aren’t cutting it, there are prescription options that address the underlying inflammation driving many chronic cases. Some prescription drops work by calming the immune response on the eye’s surface, which over time allows the tear glands to recover and produce more tears naturally. These typically take several weeks to reach full effect.
Another option is punctal plugs: tiny inserts placed into the tear drainage channels at the inner corners of your eyelids. Your eyes naturally drain tears through these small openings into the nose (which is why your nose runs when you cry). Blocking that drainage keeps tears on the eye’s surface longer. The plugs are placed in a quick office visit and can be either temporary (dissolving over weeks to months) or semi-permanent. They also help any medicated drops you’re using stay in contact with your eye longer, boosting their effectiveness.
For meibomian gland dysfunction that doesn’t respond to warm compresses, in-office treatments can apply controlled heat and pressure to express blocked glands more thoroughly than you can manage at home.
Age, Hormones, and Contact Lenses
Dry eye becomes dramatically more common after age 50, particularly in women going through menopause. Hormonal shifts affect the oil and watery components of tears simultaneously, which is why many women notice dry eye symptoms appearing alongside other menopausal changes. Contact lens wear is another major contributor at any age. Lenses sit directly on the tear film and can disrupt its structure, accelerate evaporation, and reduce corneal sensitivity over time, meaning your eyes may not signal for more tears as effectively as they should.
If you wear contacts and your eyes feel consistently dry by the end of the day, switching to daily disposable lenses or reducing your wear time can help. Some lens materials retain moisture better than others, and your eye care provider can recommend options designed specifically for dry eye sufferers.