What this means
Tears constantly wash over the surface of the eye and need somewhere to drain. If there are too many, or they cannot drain by the usual route, they spill onto the face and over time stain the coat under the eye a rusty colour. So the amount of tears alone is not enough to go on: what matters is how the eye looks and how your dog holds it.
Excess watering can come from irritation (dust, wind, a stray hair or a speck), from the shape of the eyelid or lashes, from a blocked tear duct, or from damage or inflammation of the eye's surface. In some flat-faced or prominent-eyed breeds it comes from the shape of the face. Oddly, eyes sometimes water because the quality of the tear film is poor.
Note whether one eye or both is watering, whether the tears are clear or thickened, whether the eye is red, and whether your dog squints or rubs it with a paw. Watering from one eye with squinting is a more serious sign than a light dampness in both eyes, so do not make decisions about the first yourself.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
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Irritation or a foreign body
Dust, pollen, wind, smoke or a tiny hair irritates the eye. Tears run from one or both eyes, and may stop once the irritant is gone.
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An eyelid turned inwards or stray lashes
If the lid rolls in or extra lashes grow, they scrape the surface of the eye. The eye waters, squints and sometimes reddens.
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A blocked tear duct
When tears cannot drain towards the nose they spill over the edge of the lid. A damp trail and rusty stains appear under the eye.
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Dry eye and surface irritation
When the tear film is poorer, the eye becomes irritated and waters more. You may also see stringy discharge and a dull eye surface.
About the condition: Dry eye (keratoconjunctivitis sicca) -
Inflammation or damage to the eye
Inflammation, a scratch or an ulcer on the cornea causes watering, pain and squinting. This can be a serious eye problem.
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Facial structure
In flat-faced dogs or those with prominent eyes the tear ducts and eyelids can work less well, so the watering is constant.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Whether one eye is watering or both
- Whether the tears are clear, stringy or pus-like
- Whether rusty stains or a damp trail have formed under the eye
- Whether your dog squints, rubs the eye with a paw or on the face
- Whether the eye is red or the surface looks cloudy
- Whether the watering started suddenly or has been going on a long time
When to book a routine visit
Book a visit if the eyes water daily for more than a couple of days, if stains or a wet coat have developed under the eye, if your dog squints or rubs the eye, or if the eye reddens or changes appearance. Do not wait if only one eye is watering.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Entropion Eyes Entropion is a condition in which the edge of the eyelid rolls inwards, so the eyelashes and eyelid hair rub against the surface of the eye. The constant rubbing irritates and hurts the eye and can damage the cornea, leading to ulcers. It can be inherited and show up in young dogs, and it sometimes develops later because of other changes to the eye or eyelids.
- Distichiasis Eyes Distichiasis is a condition in which extra eyelashes grow from the edge of the eyelid, where no lashes should be. Soft lashes may barely bother the eye, but stiffer ones rub against its surface. Constant rubbing irritates the eye and can damage the cornea, so whether the lashes are causing harm is for a vet to judge.
- Dry eye (keratoconjunctivitis sicca) Eyes Dry eye is a condition in which the tear glands make too few tears, so the cornea and the conjunctiva dry out and become inflamed. Without its protective tear film the eye becomes sore, and over time the cornea can darken, scar and lose its clarity. This can weaken eyesight, so changes are worth showing to a vet.
- Eye problems Eyes A dog's eyes can be affected by many different problems: faults of the eyelids and lashes, inflammation, injuries, corneal ulcers, clouding of the lens or diseases of the retina. Eyes are sensitive and some kinds of damage can get worse quickly and affect sight, so changes in the eyes are not something to wait out. If an eye suddenly turns red, seems painful or has been injured, the dog needs to see a vet immediately.
- Conjunctivitis Eyes Conjunctivitis is inflammation of the conjunctiva, the thin pink membrane that lines the inside of the eyelids and covers the white of the eye. It can be caused by dust and other irritants, allergy, infection, dry eye or faults of the eyelids or lashes, and sometimes it is part of a general illness; what caused the inflammation is for a vet to work out.
Body systems: Eyes