Dry eyes cause a distinct set of symptoms that most people can recognize at home: burning, grittiness, light sensitivity, and, counterintuitively, excessive watering. An estimated 16 million Americans have dry eye disease, and it affects women two to three times more often than men. If your eyes regularly feel scratchy or tired, especially later in the day, dry eyes are a likely explanation.
The Most Common Symptoms
Dry eye typically affects both eyes and produces a recognizable cluster of sensations. The hallmark is a stinging, burning, or scratchy feeling, often described as having something stuck in your eye. You may also notice stringy mucus in or around your eyes, redness, sensitivity to light, and blurred vision that comes and goes.
One symptom surprises most people: watery eyes. When your tear film breaks down, your eyes overcompensate by flooding with reflex tears. These emergency tears are mostly water and lack the oily, protective layer of normal tears, so they don’t actually fix the dryness. If your eyes water constantly but still feel irritated, that’s a strong signal of dry eye rather than a reason to rule it out.
Other practical signs include difficulty wearing contact lenses, eye fatigue after reading or screen use, and trouble with nighttime driving because of glare or halos. Symptoms tend to worsen as the day goes on, in dry or windy environments, and after prolonged screen time (when your blink rate naturally drops).
A Simple Test You Can Do at Home
There’s a quick self-check that mirrors what eye doctors measure in the clinic. Sit in front of a screen or fixate on an object, then try to keep your eyes open without blinking for as long as you can. Note the number of seconds before you feel discomfort or the urge to blink becomes too strong. This is sometimes called the “blink test,” and it reflects how quickly your tear film breaks down. In clinical settings, a tear breakup time under 10 seconds suggests dry eye. If you consistently can’t go more than a few seconds before your eyes sting or blur, your tear film is likely unstable.
This isn’t a formal diagnosis, but it’s a useful data point. Repeat it three times and average the results for a more reliable number.
Dry Eyes vs. Allergies
Dry eye and eye allergies share several symptoms, including redness, watering, and light sensitivity, so it’s easy to confuse them. The key difference is itching. Allergic eyes itch intensely, and the itch is usually the dominant complaint. Dry eyes burn, sting, or feel gritty, but itching is either absent or mild.
Timing also helps. Allergies tend to flare seasonally or after exposure to a specific trigger like pollen, pet dander, or dust. Dry eye symptoms are more persistent and typically get worse with screen use, air conditioning, or toward the end of the day regardless of season. You can have both conditions at once, but separating the two matters because antihistamine eye drops (a common allergy treatment) can actually make dry eyes worse.
What Causes Dry Eyes
Dry eye is rarely caused by one thing. It usually results from a combination of factors that either reduce tear production or cause tears to evaporate too quickly. Age is the biggest risk factor, with prevalence climbing steadily after 50. Hormonal changes explain much of the gender gap: women are disproportionately affected, particularly during and after menopause.
Medications are a major and often overlooked trigger. Among older adults, an estimated 62% of dry eye cases can be traced to systemic medications. The most common culprits include antihistamines (which dry out mucous membranes throughout the body), antidepressants, blood pressure medications, diuretics, and anti-inflammatory painkillers like ibuprofen. Even glaucoma eye drops cause burning and dryness in up to 47% of the people who use them. If your symptoms started or worsened around the time you began a new medication, that connection is worth exploring.
Environmental and behavioral factors pile on top of these. Prolonged screen use reduces your blink rate by as much as half, giving tears more time to evaporate. Air conditioning, heating, ceiling fans, and low-humidity environments all accelerate evaporation. Contact lens wear is another common contributor.
What Happens at the Eye Doctor
If home observations point toward dry eye, an eye care professional can confirm the diagnosis and figure out why it’s happening. The standard approach starts with a symptom questionnaire. One widely used version, the SPEED questionnaire, asks you to rate eight symptoms (dryness, grittiness, scratchiness, irritation, burning, watering, soreness, and fatigue) on both frequency and severity, producing a score from 0 to 28.
From there, the doctor may run a few painless tests. The Schirmer test places a small strip of filter paper inside your lower eyelid for five minutes to measure how many millimeters of moisture your eyes produce. Less than 10 mm in that window suggests low tear production. A tear breakup time test uses a drop of fluorescein dye to watch how quickly your tear film destabilizes under a slit lamp. Breakup in under 8 to 10 seconds is considered abnormal; 2 to 3 seconds indicates moderate to significant dryness. Some clinics also measure tear osmolarity, which tells the doctor how concentrated (salty) your tears are.
These tests help distinguish between the two main types of dry eye: one where you don’t produce enough tears and one where your tears evaporate too fast because the oil-producing glands in your eyelids aren’t working well. The distinction matters because the treatments differ.
Signs That Need Prompt Attention
Most dry eye is a chronic nuisance rather than an emergency, but certain symptoms warrant a faster visit. Persistent blurred vision that doesn’t clear with blinking, significant light sensitivity that limits daily activities, increasing redness, or worsening pain can indicate corneal damage from prolonged dryness. Left untreated over time, severe dry eye can lead to corneal abrasions or scarring that affects vision permanently. If your symptoms are escalating rather than stable, or if over-the-counter artificial tears aren’t providing any relief after a couple of weeks, that’s a reasonable point to get a professional evaluation.