Dry eyes happen when your tears evaporate too quickly, when your eyes don’t produce enough tears, or when your tears lack the right chemical balance to keep the eye surface moist. It’s one of the most common eye complaints, and the cause is usually something identifiable: screen time, medications, indoor air, or a problem with the tiny glands along your eyelids.
How Your Tear Film Works
Your eye is covered by a thin tear film that does more than keep things moist. It protects against infection, washes away debris, and keeps your vision sharp. This film has two main components: a watery mucus layer produced by your tear glands and specialized cells on the eye surface, topped by a thin oil layer. The oil layer is critical because it slows evaporation, keeping the watery layer intact between blinks.
When any part of this system breaks down, the tear film becomes unstable. That instability is the core problem behind virtually all dry eye. It leads to faster evaporation, irritation, inflammation, and the blurred or fluctuating vision that many people with dry eyes notice throughout the day.
Screen Time and Reduced Blinking
If your eyes feel dry mainly during or after using a computer, phone, or tablet, reduced blinking is almost certainly part of the problem. You normally blink about 15 times per minute. During screen use, that drops to just 5 to 7 times per minute. Each blink spreads a fresh layer of tears across the eye, so cutting your blink rate by more than half means your tear film is breaking apart and evaporating between blinks far more than it should.
The 20-20-20 rule is the simplest fix: every 20 minutes, look at something about 20 feet away for 20 seconds. This lets the focusing muscles in your eyes relax and naturally encourages fuller, more frequent blinks. It won’t cure an underlying condition, but for screen-related dryness, it makes a noticeable difference.
Indoor Air and Environmental Factors
Heating and air conditioning systems pull moisture out of indoor air, and that low humidity accelerates tear evaporation. Humidity levels of about 45% or higher are best for your eyes. Most climate-controlled offices and homes sit well below that, especially in winter. Air blowing directly on your face, whether from a car vent, a desk fan, or an overhead unit, makes things worse by speeding evaporation even further.
Dusty environments and cigarette smoke also destabilize the tear film. If you notice your eyes are worse in specific rooms or settings, the environment is a likely contributor. A small humidifier near your workspace or positioning yourself away from direct airflow can help more than you might expect.
Medications That Dry Out Your Eyes
A long list of common medications reduce tear production as a side effect. Antihistamines are the most well-known culprit, but antidepressants, blood pressure medications, diuretics, anti-anxiety drugs, and even over-the-counter pain relievers like ibuprofen can contribute. In older adults, an estimated 62% of dry eye cases can be traced back to systemic medications.
If your dry eyes started or worsened around the time you began a new medication, that connection is worth bringing up with whoever prescribed it. Sometimes an alternative drug in the same class causes less dryness, or the dosage can be adjusted.
Blocked Oil Glands in Your Eyelids
The most common cause of chronic dry eye isn’t a lack of tears. It’s a problem with the oil-producing glands that line the edges of your upper and lower eyelids, called meibomian glands. When these glands become clogged, the oil layer on your tear film thins out, and tears evaporate too fast. Over time, blocked glands can deteriorate permanently if left untreated.
The blockage happens when the ducts of the glands become plugged with thickened secretions. Eventually, the glands can shrink and stop working altogether. Signs that your oil glands may be involved include eyes that feel worse as the day goes on, a gritty or burning sensation, and eyelids that look red or feel crusty in the morning.
Warm compresses held over closed eyelids for 5 to 10 minutes help soften blocked oils and improve gland function. Doing this daily is one of the most effective home treatments for this type of dry eye. Gently massaging your eyelids afterward can help express the softened oils.
Autoimmune and Systemic Causes
Persistent, severe dryness in both your eyes and mouth can signal an autoimmune condition called Sjögren’s syndrome, where the immune system attacks moisture-producing glands throughout the body. This condition is far more common in women, particularly after age 40. Beyond dry eyes and dry mouth, people with Sjögren’s often experience joint pain, fatigue, and swollen salivary glands.
Diagnosing Sjögren’s involves blood tests looking for specific antibodies and sometimes a small biopsy from the inside of the lower lip to check for immune cell activity. It’s worth considering if your dryness is severe, affects multiple areas of your body, and doesn’t respond well to standard dry eye treatments. Other autoimmune conditions like rheumatoid arthritis and lupus can also cause dry eyes through similar mechanisms.
Choosing the Right Eye Drops
Artificial tears are the first-line treatment for most dry eyes, but not all drops are equal. If you use them more than a few times a day, preservative-free formulations are important. The most common preservative in eye drops, benzalkonium chloride, can irritate and inflame the eye surface with repeated use. In people who already have reduced tear production, the preservative stays on the eye longer and causes more damage, creating a cycle where the drops you’re using for relief actually worsen the underlying problem.
Preservative-free drops come in single-use vials rather than multi-dose bottles. They cost a bit more but are significantly gentler for daily use. If you’re also using other medicated eye drops for conditions like glaucoma, the cumulative preservative exposure makes switching to preservative-free options even more important.
What About Omega-3 Supplements?
Omega-3 fatty acids have been widely recommended for dry eyes, but the largest clinical trial on the topic found they didn’t help. In that study, patients with moderate to severe dry eye who took 3,000 mg of omega-3 daily for 12 months showed no significant improvement compared to a placebo group taking olive oil. This doesn’t mean diet is irrelevant to eye health, but omega-3 supplements alone are unlikely to resolve your dry eye symptoms.
How Dry Eye Gets Diagnosed
If home treatments aren’t enough, an eye care provider can run straightforward tests to identify the type and severity of your dry eye. One common test measures how quickly your tear film breaks apart after a blink. A breakup time under 10 seconds indicates an unstable tear film. Another evaluates the height of the tear layer along your lower eyelid, where anything under 0.25 mm suggests insufficient tear volume. There are also rapid tests that check for inflammation markers on the eye surface.
These tests matter because treatment depends on the type of dry eye you have. Someone with clogged oil glands needs a different approach than someone whose tear glands simply aren’t producing enough fluid. Getting the right diagnosis means you’re not wasting time and money on treatments that don’t address your specific problem.
Practical Steps That Help Most People
For the majority of people with dry eyes, a combination of small changes makes the biggest difference. Keep your screen at or slightly below eye level so your eyes don’t open as wide. Use the 20-20-20 rule during screen work. Run a humidifier when indoor air is dry, especially in heated or air-conditioned rooms. Switch to preservative-free artificial tears if you’re using drops regularly. Try warm compresses on your eyelids for a week and see if your symptoms improve.
If you wear contact lenses, dryness is often worse because the lens disrupts the tear film. Reducing wear time, switching to daily disposables, or using rewetting drops designed for contacts can all help. Some people find their dry eye symptoms resolve almost entirely when they switch from contacts to glasses, at least part-time.