Eye Problems in Pets

The other day I treated a cat with a swollen left eye and a yellow discharge.

After prescribing an antibiotic cream for the eye, instead of getting better, the cat’s eye got a lot worse.

The tissues around the eye had become so swollen that it was hard even to see the eyeball properly and an abscess (pus-filled lump) developed over the cat’s left cheek putting pressure on the eye.

So, what appeared to be a simple eye infection at first, presented later as a nasty tooth root abscess. Luckily Chloe was fine after the offending tooth was extracted. So eye problems in pets can be serious and not always what they seem to be. So what should you know about eye problems in pets?

As you can see in the image, cats (and dogs) have a third eyelid present in the corner of their eye. This gives additional protection against injury, by covering the eye quickly during trauma. The eye is still vulnerable to many problems.

Corneal ulcers – This is where there is a penetrating wound or scratch to the surface of the eye (the cornea). The animal usually presents with severe discomfort in the affected eye and usually can’t hold it open properly. There may be a watery or yellow discharge. Any suspicion of a corneal ulcer requires urgent veterinary attention as in some circumstances; corneal ulcers can lead to the loss of the eye if they are not treated quickly. Your vet will want to do a fluoresce in dye test, where a drop or strip of dye is placed into the eye, and a UV light is shined over the area. If an ulcer is present, it will shine a bright green colour. It is important to follow the instructions your vet gives you for treating corneal ulcers and always have a follow-up appointment to ensure it has healed.
Dry eye – Dry eye means insufficient or poor quality tear production. Tears are important because they keep the eye moist and lubricated. In pets with this condition, the eye is prone to ulcers, infections and permanent loss of vision. Sometimes there is a thick “gluggy” discharge in the corner of the eye. Certain breeds such as Poodles are genetically more prone to dry eye. Your vet can carry out a simple Schirmer tear test to determine whether your pet’s tear production is normal. There are various ointments and lubricants available to manage this problem, but it is important to act quickly before any permanent problems arise.
Conjunctivitis – Conjunctivitis is common in pets as well as people. Sometimes conjunctivitis has an infectious cause, e.g. a virus or bacteria, or in some cases; allergies cause it. In many cases, both eyes are affected, and there may be a yellow discharge present. In cats, viral conjunctivitis is very common and can often be linked to the cat flu virus. This virus tends to cause recurring eye problems in cats, particularly in times of stress, such as going to the cattery. In dogs, bacterial conjunctivitis is a common contagious disease and may even be contagious to people, so ensure you wash your hands. Usually, an antibiotic cream is prescribed, or in the case of allergic conjunctivitis, an anti-inflammatory may be used to help settle the irritation.
Glaucoma – Glaucoma is one of the most serious eye conditions seen in pets. This is where there is an increase in pressure inside the eye. If not treated rapidly, vision loss occurs. If your vet suspects glaucoma in your pet, he or she may refer to you a pet eye specialist (veterinary ophthalmologist) for further tests. Sometimes glaucoma can be secondary to a more sinister problem such as cancer in the eye. If this is suspected, an ultrasound of the eye can be carried out to look for a tumour.
Cataracts – This is where there is complete opacity of the lens and can cause blindness. This should not be confused with normal ageing changes to the lens (nuclear sclerosis). The lens is made up of several layers of cells arranged somewhat like the layers of an onion. Layers of cells are added continually throughout the animal's life. As your dog or cat gets older, new layers are added, and the cells become packed together more tightly in the centre of the lens (the nucleus). The increased density of the lens causes it to look cloudier in dogs over seven years of age. The lens will become increasingly cloudy as the animal ages, but it rarely affects vision.
In contrast, true cataracts can cause blindness. One of the most common causes of cataracts in animals (especially dogs) is diabetes. This can be corrected surgically in, and in many cases, once the cataract is removed, the pet regains some vision.