The single most common thing we hear from patients with dry eye is that they don't believe they have it. Their eyes are streaming. They're going through tissues. Dry is the last word they'd use.
But watering is one of the classic signs. When the tear film breaks down, the surface of the eye gets irritated, and the lacrimal gland responds by flooding the eye with a burst of watery tears. It's the same reflex that kicks in when you chop an onion. Those emergency tears are thin, they lack the oils that keep them in place, and they run straight down your cheek rather than coating the eye properly. So you end up with a wet face and a dry eye at the same time.
That contradiction is a decent summary of dry eye in general. Very little about it is obvious.
What dry eye actually is
Your tear film is only about seven microns thick, which is roughly a tenth the width of a human hair. It has three components working together: a mucin layer that helps tears stick to the eye, a watery layer that carries oxygen and nutrients, and a thin oily layer on top that stops the whole thing evaporating.
Dry eye disease is what happens when that film stops doing its job. The current international consensus describes it as a loss of homeostasis of the tear film, with tear instability, increased saltiness of the tears, inflammation, damage to the ocular surface, and changes in the corneal nerves all feeding into each other.
That last part matters. Dry eye is not simply a plumbing problem where you've run out of tears. It's an inflammatory condition, and inflammation is why it tends to get worse rather than better if it's left alone. Irritation triggers inflammation, inflammation damages the glands and the surface, the damage makes the tear film less stable, and round it goes.
Broadly, dry eye splits into two types:
Evaporative dry eye. You make enough tears but they disappear too fast, usually because the oily layer is thin or poor quality. This is the far more common form, accounting for the large majority of cases.
Aqueous deficient dry eye. The lacrimal gland isn't producing enough of the watery component. This is the type associated with Sjögren's syndrome and other autoimmune conditions.
Plenty of people have both.
The symptoms that don't sound like dry eye
Grittiness and burning are the ones people expect. These are the ones they don't:
• Vision that blurs and then clears when you blink. A stable tear film is the first refracting surface your eye has. When it breaks up between blinks, vision goes soft. Blink, and it sharpens again. If your sight fluctuates while you read or drive, the tear film is a likely culprit.
• Eyes that feel worse in the morning. Often a sign of poor lid seal overnight or lid margin disease rather than daytime evaporation.
• Contact lenses that used to be comfortable and now aren't. Reduced wear time is frequently the first thing patients notice.
• Tired, heavy eyes by mid-afternoon. Especially on screen-heavy days.
• Light sensitivity. An irritated cornea is a sensitive cornea.
• Stringy mucus at the inner corner.
Symptoms and clinical signs often don't line up neatly either. Some people have eyes that look terrible on examination and barely notice. Others have mild-looking surfaces and are genuinely miserable, usually because the corneal nerves have become sensitised. Neither situation means the person is exaggerating or imagining things.
What's driving it
Screens. We blink around 15 times a minute normally. Staring at a monitor can drop that to five or six, and a good proportion of those blinks are incomplete, meaning the upper lid never fully meets the lower. Incomplete blinks don't squeeze the oil glands properly, so the oily layer thins out over the course of the day.
Age. Tear production declines and the oil glands change with age. Most people over 50 have some degree of change even without symptoms.
Hormones. Dry eye is considerably more common in women, and the perimenopausal and postmenopausal years are a frequent trigger point.
Medication. Antihistamines, some antidepressants, beta blockers, diuretics, hormonal contraception, isotretinoin for acne, and several glaucoma drops can all contribute. Never stop a prescribed medicine because of this — but do mention it to whoever is treating your eyes.
Contact lens wear. Long-term wear is associated with changes to the lid margins and oil glands.
Environment. Air conditioning, car heaters blowing at the face, aeroplane cabins, central heating, and windy days all speed up evaporation.
Previous eye surgery. Laser refractive surgery cuts corneal nerves, which reduces the feedback loop that tells the eye to produce tears. Most recover, but it can take months.
Systemic conditions. Sjögren's syndrome, rheumatoid arthritis, thyroid eye disease, rosacea and diabetes are all linked.
What actually helps
Start with the mechanics
Before you buy anything, change what your eyes are doing.
The 20-20-20 principle is worth the effort: every 20 minutes, look at something around 20 feet away for 20 seconds. The point isn't really the distance. It's that shifting focus interrupts the staring and prompts a few proper blinks.
Then there's deliberate blinking. Close gently, pause for two seconds, squeeze lightly, then open. Five of those, a few times a day. It sounds far too simple to do anything, but for people with incomplete blinking it makes a measurable difference to how the oil glands empty.
Raise your monitor conversation: most people should be looking slightly down at their screen, not level or up. A lower gaze angle means less of the eye surface is exposed, and less exposed surface means less evaporation.
Lubricants, chosen properly
Not all artificial tears are the same, and the differences matter more than the price.
Go preservative-free if you're using drops more than about four times a day. Benzalkonium chloride, the most common preservative, is toxic to the corneal surface with repeated exposure. Unit-dose vials or multidose bottles with a preservative-free valve both work.
Match the drop to the problem. Sodium hyaluronate drops hold water well and suit general dryness. Lipid-containing drops, often sold as sprays or emulsions, are aimed at evaporative dry eye and are the better choice if your oil glands are the issue. Thicker gels and ointments last longer but blur vision, so they're usually a bedtime option.
Give any new drop a fair trial. Four weeks, used consistently, before you judge it.
Warm compresses, done correctly
If the oil glands are involved — and they usually are — heat is the intervention that does the heavy lifting. This is covered properly in the article on meibomian gland dysfunction, because there's more to it than holding a flannel to your face for 30 seconds.
Where a clinic comes in
If self-management isn't enough after a couple of months, there's a lot more available:
• Anti-inflammatory drops. Ciclosporin 0.1% is licensed in the UK for severe dry eye with corneal inflammation. It takes months to work and often stings initially, so expectations need setting up front.
• Short courses of steroid drops to break an inflammatory cycle, always under supervision because of the pressure and cataract risks.
• Low-dose oral doxycycline, prescribed for its anti-inflammatory effect on the oil glands rather than as an antibiotic.
• Punctal plugs. Tiny inserts that block tear drainage, keeping what you produce on the eye for longer. Genuinely useful in aqueous deficient dry eye, less so if evaporation is the problem.
• Intense pulsed light and thermal pulsation treatments for gland dysfunction.
• Autologous serum drops, made from the patient's own blood, for severe surface disease that hasn't responded to anything else.
On omega-3
Fish oil supplements were recommended fairly confidently for years. Then a large randomised trial published in 2018 found no significant benefit over an olive oil placebo, which caused a rethink. The picture now is mixed: some smaller studies still show benefit, particularly in gland dysfunction, and the trial has been criticised on the grounds that the placebo may not have been inert. It's reasonable to try, it's unlikely to hurt, but it isn't the reliable fix it was once presented as. Check with your GP if you're on anticoagulants.
When to get it looked at sooner rather than later
Most dry eye is a quality-of-life problem, not a sight-threatening one. But book an appointment promptly if you have:
• Pain rather than discomfort
• A red eye that isn't settling
• Vision loss that doesn't clear on blinking
• Any red painful eye while wearing contact lenses — this needs same-day attention
• Sudden onset alongside dry mouth or joint pain, which may point to an autoimmune cause worth investigating
The realistic outlook
Dry eye is usually a condition you manage rather than one you cure. That sounds discouraging, but managed well it stops being something you think about. The people who do best are the ones who identify what's actually driving their case — glands, tear production, blinking habits, environment, or some combination — and treat that specifically, instead of reaching for whichever drop happens to be nearest.
If your eyes have been bothering you for months and you've been getting by on supermarket drops, a proper assessment is worth booking. Tear film breakup time, osmolarity, lid margin examination and gland imaging take a few minutes and tend to explain a lot.