Watery eyes: the commonest cause is a dry eye

Why watery eyes are usually dry eyes

It sounds like a contradiction, and it is the most important sentence on this page: in the consulting room the overflowing eye is most often an eye that is too dry. Not 'too few tears' — but a tear film that no longer covers the surface evenly.

The tear film is not water but a thin set of layers: on the outside an oily film from the glands of the eyelid margin, which slows evaporation; beneath it the watery part; and innermost a layer of mucus with which the whole thing clings to the cornea. If the oily film is missing — because the glands along the eyelid margin are blocked —, the watery part evaporates too quickly. The film breaks up between two blinks, and the cornea is left exposed in places.

What happens then is a reflex and not a disease in itself. The cornea is the most densely nerve-supplied tissue in the body; a dry patch on it makes itself felt at once. The tear gland responds with a surge of thin reflex tears — too much at once, too watery, without the oily part that would hold them on the surface. They run off over the eyelid margin instead of wetting it. Shortly afterwards the surface is unprotected again, and the same thing starts over.

This pattern can be recognised from the symptoms remarkably well:

• The watering comes in waves, not as a steady trickle
• It gets worse with wind, cold, draughts, air conditioning and after longer spells of screen work
• Between the bouts there remains a burning, scratching or gritty feeling
• Usually both eyes are affected, often to unequal degrees
• Visual acuity fluctuates and improves for a moment after blinking
• Lubricating drops help — but only briefly, because the cause lies at the eyelid margin

The medical term for the overflowing eye is epiphora. It describes the symptom and nothing else: it applies to the irritated dry eye just as much as to a blocked drainage. That is why 'epiphora' is a description and not yet a diagnosis.

In practice that means two things. First: anyone who comes because of watery eyes is examined here for the tear film and the eyelid margins first, not for the tear ducts. Second: the treatment then looks entirely different from what most people expect — lubricating drops, eyelid margin care, warmth, and more depending on the findings. What lies behind it, how it is measured and what stages of treatment there are, is set out in full on the page Dry eyes: causes, measurement and targeted treatment. It is the detour that, with watery eyes, is most often the shortest way.

Tear-duct diagnostics: what irrigation and probing show

The examination does not begin at the tear ducts. It begins at the slit lamp, and in most cases it ends there too: we assess how long the tear film holds between two blinks, how the eyelid margins and their gland openings look, whether the corneal surface shows fine defects after staining, where the eyelid margin lies, how taut it is, and whether the tear punctum is open and facing the eye. Together with what you report about the course — waves or a constant state, one eye or both, burning or only wet —, that usually settles which group it is.

Only when this finding leaves the question of drainage open do the procedures follow that test the path of the tear itself.

Irrigating the tear ducts

First an anaesthetic drop goes into the eye. Then a fine, blunt cannula is introduced through the tear punctum at the inner eyelid margin and saline is injected. What you feel as this happens is the finding: if the fluid drains away freely, you taste it at the back of your throat — the passage is open, and the cause lies elsewhere. If it comes back out of the opposite tear punctum, there is an obstruction. Whether the resistance is soft or hard, and whether mucus or pus comes with it, says something more about exactly where. The examination takes a few minutes, is done in the consulting room and does not usually hurt; most people describe a feeling of pressure at the inner corner of the eyelid.

Probing

With a fine, rounded probe it is possible to feel at which point the passage ends — in the canaliculus, at the junction with the tear sac, or only further down. In adults it belongs to the same sitting as the irrigation and answers the question 'where', after the irrigation has answered 'whether'.

The same limit applies to both examinations: An acutely inflamed tear sac is neither irrigated nor probed. As long as the place beside the bridge of the nose is reddened, swollen and painful under pressure, the inflammation is treated first; the question of drainage arises afterwards. And where a firm swelling or blood-tinged tears are involved, there is no further irrigation but an assessment with imaging.

With babies it is something else: there, probing is a procedure under general anaesthetic and not an examination in the consulting room. It is therefore considered only when the watering persists and simpler measures have been exhausted — more on that further down.

When imaging is needed — and when it is not

The ordinary watering eye needs no imaging. The slit lamp, assessment of the lids and, where indicated, an irrigation answer the question. Imaging of the tear ducts stays reserved for the few situations in which the anatomy is unclear — after injuries around the bridge of the nose, after previous surgery, or with a finding that does not fit the picture. 'Does not fit the picture' means, concretely: blood-tinged tears or a bloody reflux on irrigation, a firm swelling above the inner lid ligament, or a swelling that remains or returns after the inflammation has settled. These findings need imaging, not repeated irrigation. Where imaging is called for, we arrange the examination at a suitable place rather than improvising it. The principle is the same as for any additional diagnostics here: it is done when its result changes the treatment.

And this belongs to it as well: if you come expecting that 'the tear ducts will be flushed through', and the examination shows that they are open, then we tell you so — and treat what is actually making your eye water. An irrigation without a question behind it is not a harmless extra service but an intervention in a delicate system of ducts.

Watery eyes in babies

A baby whose eye has been constantly moist since the first weeks of life, gummed up in the morning, with the tear standing on the cheek, almost always has the same thing: a congenital narrowing of the nasolacrimal duct. Before birth the lower end of the duct still lies behind a thin mucous membrane. In many children it opens with the first breaths, in some only later — and until then the tear has nowhere to go.

The most important news about it is reassuring: In the vast majority of cases it resolves on its own, usually in the course of the first year of life. It is not a malformation of the eye, it does no harm to the sight, and it is not something you could miss doing anything about at home.

What helps during this time:

1. Gentle massage over the tear sac. With a clean finger, stroke downwards from the bridge of the nose, several times a day — gently, but with noticeable, even pressure: the massage works through the pressure it builds up in the tear sac, and mere stroking achieves nothing. Your paediatrician will show you the movement once — described in words it sounds more complicated than it is.
2. Wipe away crusting with a clean cloth moistened with boiled water or sterile saline, gently over the closed eyelid, a fresh cloth for each eye.
3. Watch rather than treat. As long as the eye is moist but white and free of irritation, it needs no drops — and certainly no antibiotic ones kept in reserve.

When an assessment is needed after all: when the watering persists beyond the first year of life, or when the eye becomes inflamed repeatedly — and immediately, not 'shortly', with a reddened, swollen place at the inner corner of the eyelid that hurts on pressure, or with fever.

One constellation expressly does not belong on this list, because it means something quite different: Light sensitivity, constant screwing up of the eye and a watering eye together, particularly when the cornea looks cloudy or one eye appears larger than the other. That is not a blocked tear duct but the suspicion of congenital glaucoma, and that needs assessing within a few days — directly at a children's eye clinic.

If the narrowing persists, the next step is probing; at this age it is done under general anaesthetic, and that is precisely why it is not considered lightly. The same age rule applies to all of this here as everywhere else: We examine children from kindergarten age. With babies and toddlers we work out on the phone whether a consultation specialising in paediatric ophthalmology is the better place, and we help you find the way there. When the probing is done and where the procedure takes place are therefore discussed there and not here — we would rather say that before the appointment than after an hour of waiting.

A red eye in the first weeks of life is never a matter for waiting, whether or not it waters. Do not call us first for that, but go directly to a children's eye clinic or an ophthalmic emergency department. Where an examination without an acute reason makes sense, and what is looked at in it, is set out in the overview of our ophthalmic examinations and screening appointments.