The guilty look, the ‘please just one more’ look, those expressive, furrowed eyebrows. Puppy dog eyes. Highly adapted to get treats from the table and extra cuddles. You can tell a lot about a dog’s emotions from their eyes, but they don’t have the capacity to cry. So, if dogs do have watery eyes, what can this mean?

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‘Epiphora’ is the medical term used for excessively weepy eyes. A little epiphora can be normal for some breeds like the Poodle. You might notice some slightly orange staining on the fur in the corner of the eye from a pigment in the tears called porphyrin. Although it can be normal and harmless, ongoing epiphora should always be checked by your vet as there are some serious underlying causes too. 

The function of tears – more than meets the eye

Tears are vitally important for eye health. Their function is surprisingly wide. Not only do they protect the surface of the eye (called the cornea), they provide it with oxygen, glucose, antioxidants, antibacterial cells, they lubricate it, and they keep vision clear. Blinking ensures tears are continuously washed over the surface of the eye, which keeps it healthy and prevents it drying out.

What causes epiphora?

Epiphora generally results from one of, or a combination of, the following factors:

1) Increased production of tears

We’ve all experienced the pain of getting a tiny grain of sand in your eye, and how this can set them off weeping uncontrollably. This is because in response to an irritant, tears are produced in excess to protect the eye. In this quantity, they can’t drain away quick enough, so the tears overflow out of the eye.

2) Reduced drainage of tears

Tears are continuously produced and drain away through the nasolacrimal duct – a tiny hole you can just about see in the inside corner of your eye. This duct takes tears into the nasal cavity (which is why you need to blow your nose when you cry!). If the duct becomes blocked, maybe with some mucus, a genetic distortion of the duct, an infection, or a dental problem, the tears cannot drain away so they overflow from the eye. 

3) Trauma and anatomical differences 

Although having watery eyes is not in itself painful, dogs can get epiphora as a result of a sore eye. Caution should therefore always be taken as epiphora can be an important sign of a painful underlying problem.

Trauma

  • Dogs can physically scratch their cornea, maybe though rough play with another dog, or getting a grass seed or thorn stuck in the eye. These scratches are called corneal ulcers. Ulcers are painful and can vary in their severity depending on how deep the corneal damage is. Very shallow scratches will often heal within 7 days, but a deep scratch or penetrating injury can be very serious, sometimes requiring surgery to rectify it and prevent rupture of the eyeball.

Skull anatomy

  • This varies widely between breeds. Consider the difference in head shape between a pug and a greyhound. Brachycephalic breeds (those with flat faces e.g. Pugs, Bulldogs and Shih Tzus) with shallow orbits and large prominent eyeballs are more prone to epiphora because their eyes are exposed and prone to damage. Their short skulls and facial skin folds can also block the tear ducts, reducing tear drainage. 

Eyelid anatomy

  • Some breeds are prone to having excessive skin around their eyes and droopy eyelids (e.g. St. Bernards, Cocker Spaniels and Basset Hounds). Some dogs will also have a congenital condition called entropion, where the eyelids turn inwards and the eyelashes rub on the cornea causing a chronic irritation or ulceration. Rogue eyelashes that grow from under the eyelids can have a similar effect. Brachycephalic breeds have large eyeballs and relatively short eyelids, so when they blink the eye may not close fully; if the tear film can’t be washed over the whole surface of the cornea, the parts that are ‘missed’ can become dry and damaged. 

These anatomical abnormalities must be assessed by your vet, as they often need surgical treatment or ongoing medication to correct them. They can be present in young puppies and will be one of the things your vet checks at their first vaccinations.

Other causes of epiphora

There are many eye conditions which may also have an element of epiphora or eye discharge to them. It’s really important to get any eye problem checked by your vet, who can determine the underlying cause, and get the correct treatment started. 

Some more common conditions are outlined here: 

Bacterial conjunctivitis

This is quite common in puppies and young dogs. It will result in a red, sore / itchy eye, with a lot of thick green-yellowish discharge. It is caused by a bacterial infection and usually treated with antibiotic eye drops from your vet. 

Keratoconjunctivitis sicca

‘Dry-eye’ is an auto-immune destruction of the tear glands causing a reduction in tear production. A thick, grey, mucous discharge usually accompanies a cloudy / dull cornea. It can be painful and lead to ulcers if not addressed. Medical and surgical treatment options are available for this condition, which can be discussed with your vet.  

Allergic conjunctivitis 

Similar to hayfever in humans, dogs can suffer allergic conjunctivitis too. It may be part of a wider allergy problem and can warrant further investigations.

Eyelid masses 

Small growths or masses can grow on the margin of the eyelid, which may start to rub on the cornea as they grow. This causes epiphora in the early stages, and can progress to corneal ulcers over time. Surgical removal is the preferred treatment option. 

Uveitis 

A severe inflammation of the eye. There are many causes, and it can be serious. Epiphora is usually one sign of uveitis, along with a very red, sore eye. 

Glaucoma 

A very serious condition where the pressure inside the eye builds to dangerous levels. It is intensely painful and can result in blindness and loss of the eye.
The eye is a complicated organ. A lot can go wrong with it, and it can happen quickly. If you notice epiphora or any other changes in your dog’s eye, it should be checked by your vet. If it is accompanied by signs of eye pain (redness, swelling, rubbing / pawing at the eye, squinting), this should be checked as a matter of urgency – the sooner the treatment is started, the better chance your dog will have of making a good recovery.

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