It is that time of year again!
You, your cat, your dog... everyone is running around with red, itchy, irritated, squinty eyes... but WAIT!... is this really all allergies. Think again!
Cats and dogs can have multiple conditions in their eyes that look or appear to be “allergy” eyes, but are really the start of a serious condition.
One of the most popular veterinary sayings out there are “don’t mess with eyeballs, they go from bad to worse quickly.” (not much of a saying, but powerful and true).
As you read through you will start to notice a patten of most of the eye conditions... they all have very similar symptoms, but when you visit us we have different testing for each of these conditions. We also determine these conditions based on medical history, breed, or other health conditions. All these eye conditions have very different treatments, so it is extremely important that you see your veterinarian to ensure that you get your pet on the proper treatment.

Some eye anatomy for everyone:

  • Cornea: the clear outer covering (membrane) of the eyeball
  • Pupil: the circular membrane in the center of the eye that permits the entry of light from
    the environment
  • Iris: the round, pigmented membrane that surrounds the pupil and contracts or expands to
    regulate the amount of incoming light;
  • Lens: a transparent structure that adjusts its shape as needed to focus the light rays
  • Retina: a sensitive membrane that lines the interior surface of the eyeball, receives the
    focused light impulses that have entered through the lens, and sends them along to the
    brain, as visual information
  • Optic nerve: the channel leading from the retina to the brain
  • Third eyelid: thin, pale membrane positioned at the inner corner of the eye, between the
    lower eyelid and the eyeball. This extra eyelid helps keep the surface of the eyeball moist, protects it from being scratched by erratically growing hairs, and can help shield it.

Epiphora (Watery Eyes):
Watery eye discharge is a common concern of pet owners. Excessive tears drain down the pet’s face and, in time, the chronic exposure to moisture produces skin irritation, infection, and odor. The fur becomes stained reddish brown because the normal bacteria that live on your pet’s skin starts to ingest the tears.  The tear pigment is called porphyrins, an especially non-cosmetic problem in pets with white fur.
BUT WAIT... this can be due to other conditions, medical conditions as well. There could be some type of external irritant in your pet’s eye (debri, dust, hair, etc). Some breeds of dogs naturally have hair in their eyes and this does not cause irritation in most cases, but in some cases it can. Hairs can grow from the face onto the eye and cause irritation. Eyelashes can grow at abnormal angles and rub on the eye. Eyelashes can even grow on the inner surface of the eyelids or corner of the eye and cause irritation. These can sometimes be difficult to see. These tiny hairs typically need to be surgically removed.

You should always consult a veterinarian to determine if this is truly excess tearing or due to some type of irritant in your pet’s eye that is causing the excess tearing (remember... eyes go from bad to worse quickly!)

Herpesvirus:

This virus in cats causes conjunctivitis (inflammation of the tissue surrounding the eye) and/or corneal ulcers.  Viruses are not necessarily living things, but can contain some of the same building blocks that make us “alive”.  Some of these things are proteins and nucleic acids (DNA).  When a virus finds a host to live in it can then reproduce.  It finds cells to attach to and replicate by injecting their DNA into the hosts.  This is why it is very tricky to treat viruses, because they hide among their hosts DNA. Herpesvirus is a common respiratory infection that causes an upper respiratory disease in most cats. No cat can escape the exposure of the herpesvirus... your cat can get it whether they come from a breeder, cattery, rescue, foster, etc. Every breed, every age is susceptible too. Every kitten is exposed to this virus following birth, because they are exposed from their mom. As a respiratory disease, the virus is acquired by aerosol, that is one cat sneezing around another cat. You typically see cats with red, irritated, squinty eyes (this may be one eye or both) (this is a more of a minor flair up). But cats with a more severe flair up they can have redness, irritation, sneezing, discharge from eyes/nose, not eating, lethargic, dehydration ulcers on the eyes. Your pet needs veterinary attention in both cases to help with limit the exposure of the virus, limit the time of virus, and help with all the secondary symptoms that are also occurring.

Conjunctivitis can occur at any age. Neonatal conjunctivitis occurs in kittens who have not yet opened their eyes, this can sometimes lead to permanent eye damage, depending on the severity or the virus.  In cats with herpesvirus, it is a chronic condition. Cats have constant flair ups. This may occur twice in their lifetime, it may occur every year. Most commonly it will flair up in times of stress (their immune systems are compromised and depressed, allows the virus to overtake and replicate).

WAIT... Always be sure to contact your veterinarian if you suspect your cat has herpesvirus. Herpesvirus can turn into corneal ulcers and more severe issues (this means very different treatments). And remember... eyes go from bad to worse quickly!

Corneal Ulcers:
A corneal ulcer is a wound on the surface of the eye. The damage would be similar to a scrape or cut on your skin; both problems result in an unprotected wound. The normal cornea is covered by a layer of tissue called the epithelium.  When the epithelium is damaged, infections can occur and result in complete perforation of the eye if left untreated. Clinical signs of a corneal ulcer include: squinting, redness, cloudiness, tearing, and lethargy. A special stain called fluorescein is used to identify the ulcer on the cornea. There are many causes of corneal ulcers such as injuries/trauma, abnormal eyelashes that irritate the surface, lack of tear production, or infections. These are often extremely painful to pet’s. They must be treated immediately.
You must see your veterinarian immediately. Sometimes you cannot always see the ulcer without the use of the stain. If you do not treat immediately... the eye goes from bad to worse quickly!

Nuclear Sclerosis: 

Nuclear sclerosis is the medical term for a bluish transparent "haze" that develops in the lens of the eye in middle-aged to senior dogs. This is considered a normal change in the lens associated with aging, and is observed as a cloudiness or bluish discoloration on the pupil. The lenses with nuclear sclerosis may look cloudy but they are still clear and the dog can still see through them; these are not cataracts. Your dog is still able to see, but if you can imagine yourself being visual, but with a permanent shade over your eyes. You might notice your pet having more difficulty at night too.  The normal lens of the eye is a focusing device. It is completely clear and is suspended in position by tissue fibers called zonules that are just inside the pupil. The lens focuses an image on the retina in the back of the eye in a process called accommodation. The focusing power of the dog’s lens is at least three times weaker than that of a human, while a cat’s lens is at best half the focusing power as a human’s. (Dogs and cats have a sense of smell at least 1000 times more accurate than ours and this is their primary means of perceiving the world.) You need to ensure that there are no secondary issues arising, inflammation can occur with this condition and result in uveitis. Remember... eyes go from bad to worse quickly!

Cataracts:
Cataracts are opacities in the lens of the eye (which is deep within the eye, not to be mistaken for a film over the eye). Most cataracts are inherited, and are found in many breeds such as the Cocker Spaniel, Poodle, Husky, Schnauzer, Golden and Labrador Retrievers, and terriers. Other causes of cataracts include: Diabetes, trauma, inflammation, and puppy milk replacers. A cataract can move, which means that it can slip from the tissue strands that hold it in place. The cataract can float around in the eye where it can cause damage. If it settles so as to block the eye’s natural fluid drainage, glaucoma (a buildup in eye pressure) can result, leading to pain and permanent blindness. A cataract can also cause glaucoma when it absorbs fluid and swells so as to partially obstruct fluid drainage. Cataracts on occasion can begin to dissolve after they have been there long enough (rare). While this sounds like it could be a good thing, in fact it is a highly inflammatory process. The deep inflammation in the eye creates a condition called uveitis, which is in itself painful and can lead to glaucoma.

To determine if your pet has a cataract or the secondary conditions associated with it you must see you veterinarian. There are a few treatment options available, but to determine which is best for your pet will be discussed with the doctor. Remember... eyes go from bad to worse quickly!

Entropion: 

Entropion is an inward rolling of the eyelid. Although the exact genetic pattern is usually not known, the condition is considered to be breed-related in several breeds, including the Shar Pei, Chow Chow, Bulldog, Retrievers, and Rottweiler.
Problems associated with the entropion, such as corneal ulceration caused by irritating lashes or hair.

A veterinarian will be able to determine if your pet has entropion and if your pet needs surgical repair. This is typically determined when your dog is young. You also want to ensure your pet is not having any secondary issues which can cause severe issues in themselves (such as ulcers). Remember... eyes go from bad to worse quickly!

Glaucoma:
Glaucoma is defined as an increase in pressure in the eye with a loss of vision. The signs of glaucoma include: redness, cloudy eye, tearing, loss of vision, an enlarged eyeball, lethargy, and loss of appetite. The disease is quite painful in most cases, especially when the eye pressure is very elevated. Human patients complain of severe headache or migraines.
Inside the eye, a clear fluid called aqueous humor circulates in the front chamber between the cornea and the pupil. The aqueous humor leaves the eye through a small structure between the base of the cornea and front of the iris. Normal pressure is a dynamic function of the balance between aqueous production and drainage. When this does not work probably or becomes clogged, or when the flow of aqueous through the pupil becomes obstructed, intraocular pressure can increase to an unsafe level. This is particularly true if aqueous production continues at a normal level. Some patients have primary glaucoma where there is no concurrent disease. Primary glaucomas are usually breed-related. Breeds predisposed to inherited glaucoma include: Cocker Spaniels, Bassett Hounds, Beagles, Chinese Shar Pei, Chow Chows and Jack (Parsons) Russell Terriers. Secondary causes of glaucoma include: inflammation, trauma, tumors and Luxated lens. All of these factors can obstruct the drainage of fluid from the eye. Acute glaucoma is an ophthalmic emergency and must be treated immediately. If the pressure remains elevated for even a few hours, permanent vision loss occurs.
This is an emergency! See your veterinarian if you think these symptoms are occurring! Remember... eyes go from bad to worse quickly!

KCS: 

Keratoconjunctivitis sicca (otherwise known as KCS or "Dry eye syndrome") results from insufficient tear production. The cause of dry eye is often unknown but some known causes include: congenital disorders (lack of tear producing gland), infections (canine distemper virus), drug-induced (sulfa antibiotics), removal of the lacrimal gland of the third eyelid ("cherry eye"), cats with herpesvirus, and hypothyroidism. The disease is seen commonly in certain breeds such as the Cocker Spaniel, Shih Tzu, Lhasa Apso, Bulldog, Schnauzer, and West Highland White Terrier.

The clinical signs of dry eye include: heavy mucus production, redness, rubbing at eyes, cloudy eyes, corneal ulcers, and even general lethargy. After an extended period of dryness, the surface of the eye (cornea) begins to develop pigmentation and blood vessels, often causing diminished vision.

If you suspect your pet has this condition, you should see a veterinarian to determine if this is truly the problem. Remember... eyes go from bad to worse quickly!

Uveitis:
Uveitis (intraocular inflammation) refers to an inflammation of the part of the eye that supplies blood to the eye. When the blood vessels become inflamed blood cells and proteins leak out and result in cloudiness. Clinical signs of uveitis include: cloudiness, redness, tearing, squinting, occasional intraocular hemorrhage, and loss of vision.
There are many causes of uveitis such as trauma or cataract formation. Many types of infections and tumors can cause uveitis in the dog and cat. Some of the infections in dogs include: Rocky Mountain Spotted Fever, Lyme disease, Ehrlichia, infected uterus in females, hepatitis virus, and systemic fungal infections. In cats the causes can include: feline leukemia virus, feline AIDS virus, FIP virus, Toxoplasmosis and Bartonella. However, patients may have idiopathic uveitis, with no identified underlying cause. Uveitis can result in several eye complications such as cataract formation, scar tissue, retinal disease, and glaucoma.
Remember... eyes go from bad to worse quickly!

If you have any further questions please call the Village Veterinary Clinic of Hamburg 716.646.4023!

- American College of Veterinary Ophthalmologists

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