Your pet's eyes: normal gunk, tear stains, and the signs that mean a vet today

Eyes are worth paying attention to precisely because they don't forgive delay: a problem that would be minor anywhere else can threaten sight in a day or two on an eye.

The useful skill isn't treatment — most eye problems are a vet's job — but triage: knowing the difference between the ordinary bit of gunk that means nothing and the handful of signs that mean pick up the phone. Most of eye care is looking, gently wiping away the normal, and acting fast on the abnormal.

What is normal, and how to clean it

A small amount of clear or slightly brownish matter in the corner of the eye overnight is normal, the eye's ordinary housekeeping.

Wipe it away with a clean piece of damp cotton wool, using a fresh piece for each eye so you never carry anything from one to the other, and wiping outward and away from the eye, not towards it. Never put a human eye drop, cleaner or any other product near a pet's eye unless a vet has told you to — many are actively harmful, and the eye is the last place to improvise.

It's also worth knowing what a healthy eye looks like on your own animal, because every judgement that follows is a comparison. Both eyes the same size and shape, open equally, the white genuinely white, the surface clear and glossy with a sharp reflection in it, the pupils matching, and no obvious discomfort in bright light. Take thirty seconds to look properly one evening and you'll spot a change months before you'd otherwise notice it.

Long hair around the eyes is its own small job. Hair that touches the surface of the eye scratches it, and a fringe permanently wet with tears turns into a sore patch of skin. Trim it with blunt-ended scissors, with the blades pointing away from the eye and somebody else holding the dog if it fidgets — or leave it to a groomer, which is the honest answer for most people.

The signs that mean a vet, promptly

Some things aren't cleaning jobs and shouldn't wait.

A green or yellow discharge, redness across the white of the eye, obvious swelling, cloudiness or a bluish haze, or a pet squinting, holding the eye shut, or pawing and rubbing at it all mean an eye that needs looking at, and soon. So does an eye that's suddenly weeping far more than usual, or one the animal is clearly protecting. Pain and light-sensitivity around an eye escalate quickly, so this is a category where same-day is the right instinct, not wait-and-see — a scratch on the surface of the eye, for instance, can worsen fast and needs treatment early to heal cleanly.

A handful of things are worse still and mean now, not today: an eye that's visibly bulging or out of its socket, one that's been struck or has something stuck in it, a pupil that's suddenly a different size from the other, or an animal that's bumping into furniture. Never try to remove an object from an eye yourself, and don't let the animal rub — a cone or a sock over a paw on the way to the car prevents a great deal of extra damage.

One preventable cause is worth naming because it's so common: a dog with its head out of a car window. Grit at speed scratches a cornea easily, and it's an entirely avoidable injury.

Tear stains: mostly cosmetic, occasionally not

The reddish-brown streaks that run down from the inner corner of the eye in many light-coloured dogs and cats are tear staining, and most of the time they're a cosmetic matter and not a health one — the pigment in tears simply shows up on a pale coat.

Keeping the area gently wiped and dry helps, and there's no need to reach for the marketed 'tear stain removers', some of which contain things you wouldn't want near an eye. What is worth noting is a change: staining that suddenly increases, or appears alongside any of the warning signs above, can mean the eye is producing more tears for a reason — a blocked drainage duct, an irritation, an inturned eyelash — and that's a vet conversation rather than a grooming one.

Damp fur is the part actually worth managing, since a permanently wet fold of skin gets sore and can become infected. Wipe it dry with cotton wool once a day, keep the hair short there, and leave the colour alone. Nothing containing bleach or an antibiotic should go near an eye because a website suggested it.

Flat-faced breeds need extra watching

The same short-muzzled shape that defines pugs, bulldogs, French bulldogs and Persians also gives them prominent, exposed eyes with shallow sockets, and that comes with a higher rate of eye trouble — from ulcers to tear-drainage problems to, in the worst cases, an eye that can be displaced by an injury.

If you have a flat-faced breed, look at the eyes daily as a matter of routine, know that they're more vulnerable than most, and have a lower threshold for calling the vet about them.

Two other groups deserve the same attention. Older animals develop a bluish haze in the lens that's usually a normal ageing change and not a cataract, but the two look alike from the sofa and only an examination tells them apart — so it's worth asking at the next check-up instead of guessing. And any pet losing its sight gradually copes remarkably well at home, right up until you move the furniture, which is worth knowing before you redecorate.

Giving eye medication, if it comes to that

Most owners end up doing this at some point, and a few minutes of technique makes it far easier.

Steady the head from above rather than coming at the face from the front, tilt the nose slightly upward, and rest the heel of your hand on the skull so the dropper moves with the animal instead of against it. Drop the medication onto the eye from a little above without touching the surface with the nozzle, which contaminates the bottle and frightens the patient. If there are two different medications, leave several minutes between them, or the first is simply washed out by the second.

Finish with something the animal likes, every single time. A cat that has been paid for eye drops is a cat you can treat twice a day for a fortnight; one that hasn't will be under the bed by day three.

Eyes rarely need the regular attention that ears or teeth do, and the goal isn't a routine so much as a habit of noticing. Glance at them when you groom, wipe away the ordinary, and treat the warning signs as the urgent things they are — with eyes, acting a day early is always better than a day late.