Symptoms patients notice
- Burning, stinging, gritty, or sandy sensation
- Fluctuating or blurry vision, especially with screens
- Excessive tearing, redness, or light sensitivity
- Eye fatigue while reading, driving, or using digital devices
- Contact lens intolerance or discomfort after LASIK or cataract surgery
Dry eye can affect visual comfort, concentration, work productivity, and daily quality of life. Watery eyes can also be part of dry eye when an unstable tear film triggers reflex tearing.
The tear film
The tear film is a layered structure that keeps the eye comfortable and vision clear. The lipid layer, produced by the meibomian glands, helps prevent evaporation. The aqueous layer hydrates and nourishes the ocular surface. The mucin layer helps tears spread evenly across the eye.
Dry eye symptoms can develop when any of these layers becomes unstable or insufficient.
Evaporative dry eye
Evaporative dry eye is the most common pattern. Tears may be produced in adequate volume, but they evaporate too quickly because the oily layer of the tear film is not functioning well.
The most common cause is meibomian gland dysfunction, where the eyelid oil glands become blocked, inflamed, or damaged.
Aqueous-deficient dry eye
In aqueous-deficient dry eye, the lacrimal glands do not produce enough watery tears. This can be associated with ageing, medications, hormonal change, autoimmune disease, Sjögren's syndrome, or previous ocular surgery.
Patients often describe persistent dryness, burning, foreign-body sensation, and difficulty with reading or driving.
Mixed dry eye
Many patients have a mixed pattern: reduced tear volume, evaporative loss from MGD, eyelid inflammation, and ocular surface irritation may all be present together.
Treating only one component may leave symptoms unresolved. The purpose of evaluation is to identify the dominant contributors and prioritise treatment.
Conditions that contribute
- Blepharitis, rosacea, Demodex, or allergies
- Contact lens wear or long hours of screen use
- Autoimmune disease or thyroid eye disease
- Incomplete eyelid closure or previous eyelid surgery
- Entropion, ectropion, or other eyelid-position problems
Demodex mites and dry eye
Microscopic Demodex mites commonly live on human skin and eyelashes. In small numbers they are usually harmless, but overgrowth can contribute to chronic eyelid inflammation, meibomian gland dysfunction, and persistent dry eye symptoms.
Typical clues include itching on waking, red or irritated eyelid margins, crusting around the eyelashes, recurrent styes or chalazia, and a foreign-body sensation. A classic sign is cylindrical dandruff: sleeve-like debris around the base of the eyelashes.
Contact lenses and dry eye
Contact lens wearers may develop burning, irritation, fluctuating vision, or discomfort toward the end of the day. Sometimes the lens contributes to tear-film instability; in other cases, underlying dry eye disease makes lenses increasingly difficult to tolerate.
Patients often describe lenses feeling dry after several hours, redness after removal, frequent need for lubricating drops, or gradually decreasing contact lens tolerance over time.
Dry eye and screen time
Long periods on computers, tablets, and phones reduce blink rate and often lead to incomplete blinking. This can increase evaporation, worsen MGD, and contribute to digital eye strain.
Air conditioning, office environments, and remote work can add to symptoms. Blink pattern can be assessed as part of advanced dry eye imaging.
Dry eye and blurry vision
The tear film is the first refractive surface of the eye. When it becomes unstable, vision can fluctuate, especially during reading, screen use, or driving.
Many patients notice that vision clears briefly after blinking and then becomes blurry again. In some cases, the issue is tear-film instability rather than a change in glasses prescription.
Hormonal dry eye
Hormonal change, especially during and after menopause, can influence tear production, meibomian gland function, and ocular surface inflammation.
This is one reason dry eye is particularly common in women aged 45-70, although it can affect patients of any age.
Autoimmune and thyroid disease
Dry eye can be associated with systemic conditions such as Sjögren's syndrome, rheumatoid arthritis, lupus, and thyroid eye disease.
When tear volume is significantly reduced or symptoms are unusually severe, the dry eye assessment may raise the question of whether systemic evaluation is needed.
Rosacea and eyelid inflammation
Ocular rosacea can affect the eyelids and meibomian glands even when facial skin symptoms are mild. It may contribute to lid inflammation, gland obstruction, recurrent styes or chalazia, and chronic irritation.
Recognising rosacea-related eye disease is important because treatment often needs to address the eyelid margin as well as the tear film.
Dry eye and sleep
Some patients feel worst on waking. Morning dryness can be related to sleeping with the eyes slightly open, poor eyelid closure, CPAP airflow, or overnight exposure of the ocular surface.
These patterns are assessed differently from symptoms that mainly occur during screen use or late in the day.
Dry eye after cataract surgery
Dry eye symptoms can become more noticeable after cataract surgery, especially when tear-film instability or MGD was already present before surgery.
Optimising the ocular surface can improve comfort and may also support more reliable measurements and visual quality around cataract care.
Dry eye or allergy?
Allergy often causes itching, seasonal flares, swelling, and mucus, while dry eye more often causes burning, grittiness, fluctuating vision, and tear-film instability.
There is substantial overlap, and some patients have both. Examination helps avoid treating every irritated eye as allergy when dry eye or eyelid disease is the main driver.