Your eyes feel dry because your tear film, the thin coating of moisture that protects the surface of your eyes, is either evaporating too fast or not being produced in sufficient quantity. This can happen for dozens of reasons, from staring at a screen all day to taking certain medications, and the feeling ranges from mild grittiness to persistent burning. Dry eye affects anywhere from 5% to 50% of people depending on the population studied, making it one of the most common eye complaints worldwide.
How Your Tear Film Works
Your tears aren’t just water. They’re a three-layer structure called the tear film: an outer oily layer, a middle watery layer, and an inner mucus layer. Each layer has a job. The mucus layer helps tears stick evenly to the eye’s surface. The watery layer, which makes up the bulk of what you think of as tears, keeps the eye hydrated and washes out debris. The oily outer layer acts as a seal, slowing evaporation so moisture stays on the eye longer.
When any of these layers is insufficient or unbalanced, the tear film breaks down. The most common culprit is a problem with the oily layer, which is produced by tiny glands along your eyelid margins called meibomian glands. When these glands get clogged or stop producing enough oil, tears evaporate too quickly, leaving the eye surface exposed and irritated. This condition, meibomian gland dysfunction, is the leading cause of evaporative dry eye. Symptoms include burning, redness, a gritty “something in my eye” sensation, blurred vision, and paradoxically, watery eyes as your body tries to compensate for the dryness.
Screens Slash Your Blink Rate
If your eyes feel driest after hours at a computer or phone, there’s a straightforward explanation. You normally blink about 17 times per minute. When you focus on a screen, that drops to roughly 4 times per minute. Each blink spreads a fresh layer of tears across your eye, so when you blink a quarter as often, your tear film dries out between blinks. Over hours, this causes cumulative surface drying that leaves your eyes feeling scratchy, tired, and strained by the end of the day.
The fix is deceptively simple: the 20-20-20 rule. Every 20 minutes, look at something 20 feet away for 20 seconds. This gives your eyes a chance to relax their focus and resume a normal blink rate. It won’t cure an underlying dry eye condition, but for screen-related dryness it makes a noticeable difference within days.
Your Environment Matters More Than You Think
Dry indoor air is a major trigger. Heating systems in winter, air conditioning in summer, and airplane cabins year-round all pull moisture from the air and from your eyes. A large study classified participants by the humidity of their living environment and found that people in areas with relative humidity below 70% had a dry eye prevalence of 17.7%, compared to 13.6% for those in higher-humidity environments. That gap may sound small, but it translates to millions of additional cases driven purely by where people live and work.
Ceiling fans, car vents aimed at the face, and prolonged wind exposure have the same effect. If your eyes feel worse in certain rooms or seasons, the air itself is likely part of the problem. A desktop humidifier, repositioning air vents so they don’t blow directly at your face, and wearing wraparound sunglasses outdoors on windy days can all reduce evaporative stress on your tear film.
Medications That Dry Your Eyes
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 includes antihistamines (the most well-known culprit), antidepressants, blood pressure medications, diuretics, anti-anxiety medications, pain relievers, and even some anti-inflammatory drugs. If your dry eye symptoms started around the same time you began a new medication, that connection is worth discussing with your prescriber. In some cases, switching to an alternative in the same class can resolve the problem.
Autoimmune Conditions and Dry Eyes
When dry eyes come paired with a persistently dry mouth, the combination can point to Sjögren’s syndrome, an autoimmune condition where the immune system attacks the glands that produce moisture. The eyes burn, itch, and feel like they have sand in them. The mouth feels cottony, making it hard to swallow or speak. Beyond dryness, Sjögren’s can cause joint pain and stiffness, skin rashes, a persistent dry cough, and fatigue. It frequently overlaps with other autoimmune diseases like rheumatoid arthritis and lupus.
Sjögren’s is worth considering if your dryness is severe, affects multiple parts of your body, and doesn’t respond well to standard dry eye treatments. A rheumatologist can run blood tests and evaluate salivary gland function to confirm or rule it out.
Other Common Causes
Age is the single biggest risk factor. Tear production naturally declines over time, and the meibomian glands gradually lose function. Hormonal changes during menopause accelerate this process, which is one reason dry eye is more commonly reported by women in midlife and beyond. Contact lens wear also contributes, because lenses sit on the tear film and can disrupt its structure, leading to faster evaporation and reduced oxygen reaching the cornea.
Incomplete eyelid closure during sleep, common after certain cosmetic procedures or simply due to anatomy, can cause dryness that’s worst upon waking. Allergies can trigger a cycle of irritation and rubbing that damages the tear film. Even dehydration plays a role: if you’re not drinking enough water, your body has less fluid available for tear production.
Choosing the Right Eye Drops
Over-the-counter artificial tears are the first-line treatment for most dry eye, but not all drops work the same way. Aqueous-based drops add moisture directly, replacing the watery middle layer of the tear film. Lipid-based drops contain an oily component designed to reinforce the outer layer and slow evaporation. Clinical trials have found the two types perform comparably in terms of comfort and symptom relief, so lipid-based drops are a reasonable choice for anyone whose dryness stems from fast evaporation, while aqueous drops work well for general moisture supplementation.
A few practical tips: preservative-free single-use vials are gentler on the eye surface, especially if you’re using drops more than four times a day. Thicker gel drops last longer but can blur vision temporarily, making them better suited for bedtime. Avoid drops marketed as “redness relief” products, which work by constricting blood vessels rather than restoring the tear film and can cause rebound redness with regular use.
Habits That Protect Your Tear Film
Beyond the 20-20-20 rule, a few daily habits can meaningfully reduce dry eye symptoms. Position your computer screen slightly below eye level so your eyelids cover more of the eye’s surface while you work. This small change reduces the exposed area where tears can evaporate. Warm compresses held against closed eyelids for 5 to 10 minutes help soften clogged oil in the meibomian glands, improving the quality of the oily tear layer. Omega-3 fatty acids from fish, flaxseed, or supplements have shown some benefit for tear quality in clinical studies, though results vary between individuals.
If you sleep with a fan on or in a dry bedroom, overnight moisture loss can leave you waking up with gritty, uncomfortable eyes. A humidifier in the bedroom or a thicker gel lubricant applied before sleep can bridge that gap. For persistent symptoms that don’t improve with these measures, an eye care provider can evaluate your meibomian glands, measure your tear production, and discuss prescription options that target the underlying inflammation driving many chronic dry eye cases.