Eye Archives - Birnam Veterinary Clinic

Uveitis

Uveitis – pronounced ‘yoo-vee-i-tis’ – refers to inflammation inside the eye. The disease can occur in dogs and cats of any age and breed. Patients with uveitis will show signs of pain, redness and cloudiness of the eye. There are many potential causes and sometimes the cause is never found. Prompt treatment is necessary to avoid severe long-term consequences; even blindness. In this article we will discuss the possible causes, symptoms, diagnosis and treatment of uveitis in pets.

What causes uveitis in animals?

The causes of uveitis are classified as being ocular (as a direct result of a disease or injury to the eye) or systemic (as a result of a disease elsewhere in the body).

Ocular causes of uveitis

Corneal ulceration: Wound or an open sore on the outer surface of the eye
Necrotising scleritis: Severe inflammation of the tissues surrounding the eye
Deep keratitis: Inflammation of the surface of the cornea (the clear outermost layer of the eyeball)
Cataracts
Trauma to the eye, either penetrating injuries or blunt trauma
Lens luxation: Dislocation of the lens (clear structure within the eye that focuses incoming light on the retina)
Tumours inside the eye

Systemic causes of uveitis

Infectious diseases:
- Septicaemia or toxaemia: Blood poisoning caused by bacterial infections
- Canine ehrlichiosis (tick disease)
- Toxocariasis (worms)
- Toxoplasmosis (parasites)
- Feline immunodeficiency virus (FIV)
- Feline leukaemia virus (FeLV)
- Feline infectious peritonitis (FIP)
- Canine distemper virus (CDV)
Immune-mediated inflammatory disease
- Immune-mediated thrombocytopaenia (IMTP): The body’s immune system attacks blood platelets
Metabolic disorders
- Diabetes mellitus
- Hyperlipidaemia (high blood fat levels)
Systemic hypertension (high blood pressure)
Cancer

One of these underlying causes will trigger an inflammatory cascade that can permanently damage the structures within the eye. Unfortunately, in the majority of cases a cause cannot be identified, so the disease is considered idiopathic (with no known cause) and treated symptomatically. See below for the various forms of treatment.

Symptoms of uveitis

The symptoms of uveitis are either acute symptoms (those that are seen when it initially starts) or chronic symptoms (those that occur as the inflammation continues over a period of days to weeks). The symptoms of uveitis can be seen in one or both eyes.

Acute Symptoms	Chronic Symptoms
Redness	Deformity of the pupil
Cloudiness	Discolouration of the iris
Pain (face rubbing, squinting or keeping the eye shut)	Attachments of the pupil to other structures in the eye
Discharge	Cataracts
Photophobia (avoiding bright light)	Lens luxation
Small or constricted pupils	Swollen or shrunken eye
Blood or pus within the eye	Blindness

If your pet is showing any discomfort, redness or discharge from the eye, make an appointment with the vet immediately.

How is uveitis diagnosed?

The veterinarian will start by taking a careful history of how your pet’s condition developed, followed by a thorough physical exam. Be sure to provide as much information to the vet as possible, as this will help to determine possible causes and assist with the diagnosis. A systematic ocular exam will be performed, which may include the following:

Schirmer tear test: Determines if your pet’s tear glands are functioning adequately
Ophthalmoscopic exam: Careful examination of all structures of the eye using magnification
Fluorescein stain: Test to detect corneal ulceration
Tonometry: Test for intraocular pressure
Ocular ultrasound: To visualise internal structures of the eye

Depending on the findings, further specific tests on the eyes may need to be performed. Since uveitis can have systemic causes elsewhere in the body, it is important to do various blood and urine tests in order to identify a potential underlying cause.

If there is any indication of a specific condition that may be causing the uveitis, other tests may be necessary, such as chest X-rays, abdominal ultrasound or sample collection from other organs such as lymph nodes.

The veterinarian will be able to perform most of these tests; however, referral to an eye specialist is often recommended as some of the tests are more specialised in nature.

How do you treat uveitis in dogs?

If the underlying cause of the disease can be identified, it needs to be treated. However, often the cause is not found, so the vet offers treatment for the various symptoms.

The mainstay of treatment is the use of anti-inflammatory drugs such as corticosteroids or non-steroidal anti-inflammatory drugs. These can be given topically in the form of eye drops or systemically in the form of injections or tablets. As the disease is driven by the immune system, other immune-suppressive drugs may be needed.

If a bacterial infection is present in the eye or in other parts of the body, topical or systemic antibiotics will be given to treat the infection.

Mydriatics are drugs that are used topically to relieve the pain response (known as blepharospasm). The most commonly used mydriatic drug is atropine. Topical morphine may also be used for this purpose. Lubricant eye drops may be necessary to keep the cornea moist.

If concurrent conditions such as glaucoma (increased pressure inside the eyeball) are present, it will need to be addressed with additional treatments. Patients should be kept indoors in dark areas as they will be light sensitive. If the patient has a lens-associated uveitis due to a lens luxation or a cataract, they will need surgery to remove the lens.

Conclusion

Uveitis is a severe condition of the eye that can result in chronic glaucoma, blindness or the loss of one or both eyes. Many cases recur or relapse and will require ongoing treatment. If you see any abnormalities with your pet’s eyes, make an appointment to see the vet as soon as possible.

Corneal Ulceration

My pet’s eye is half-closed and there seems to be something in their eye

What is a corneal ulcer?

A corneal ulcer is damage to the corneal surface, which is the thin, clear covering of the eye. The cornea is made up of three layers: the outer epithelium, the stroma (which is thickest and acts as the scaffold) and the Descemet membrane. All three layers are transparent, allowing light to enter the pupil and create an image that our brain interprets as the sights we see around us.

https://www.allaboutvision.com/resources/cornea.htm

How does a corneal ulcer occur?

The most common cause of an ulcer on the cornea is due to trauma. Damage may occur from a sharp object like a cat scratch or from your pet rubbing their eye on a rough surface. Damage can also occur from chemical irritation like getting shampoo in the eye or even if something rough gets caught under the eyelid, scratching the eye every time they blink.

Infections from viruses or bacteria can also lead to corneal ulceration. There are some systemic diseases that can lead to corneal ulcers such as diabetes mellitus, Cushing’s disease or low thyroid hormone levels (hypothyroidism).

Corneal ulcers can also occur due to lack of sufficient lubrication of the eye. This is a medical condition called keratoconjunctivitis sicca (KCS), commonly known as ‘dry eye’.

Some breeds such as the boxer can inherit a degenerative condition called epithelial dystrophy. Epithelial dystrophy causes a weakening of the outermost surface (epithelial layer) of the cornea, easily leading to corneal ulceration.

How bad is a corneal ulcer?

Damage to the cornea is characterised into three parts depending on the depth and severity of the injury.

The superficial injury to the outermost surface (epithelium) is called a corneal abrasion or erosion.

Damage that extends past the epithelium into the stromal layer is termed a corneal ulcer.

Injury that extends through the stroma and affects the final layer of Descemet membrane is called a Descemetocele. If this final layer is damaged and the outer surface of the cornea is ruptured, the globe of the eye will lose its structure the animal will lose their eye.

How do I know if my pet has a corneal ulcer?

Corneal ulcers are painful. If a pet has a corneal ulcer, they will usually keep their eye tightly closed, often tearing excessively and often pawing/rubbing at their eye. When the eye is opened, the white of the eye (the sclera) is often red and the area around the eye known as the conjunctiva may be pink due to the irritation and may be swollen. In the cases of large ulcers a depression or even a crater-like cavity can be seen on the surface of the eye. The outer edges of the ulcer absorb moisture from the tears and can appear cloudy or even white. This change is called corneal oedema and is sometimes the only sign that there has been damage to the surface of the eye.

Can a corneal ulcer be treated?

Yes. Corneal ulcers should be treated, even if they appear small and insignificant. Once the outer epithelium of the eye has been damaged, bacteria often take advantage of the opening and can start colonising the now vulnerable second or stromal layer. Once bacteria have a foothold they cause the ulcer to degenerate and enlarge, potentially to the point of loss of the eye. Corneal ulcers are not to be scoffed at.

What will the vet do if my pet has a corneal ulcer?

When the vet examines your pet’s eye they will use a fluorescein dye that will cause a colour change to show the presence of damage to the cornea. With a special ophthalmic light, this allows the vet to visualise the extent of the damage and also monitor the ulcer size once treatment has begun.

Corneal ulcers are usually treated with antibiotic eye drops and the vet may also prescribe eye drops or oral medication for pain. The vet may also include anti-inflammatory eye drops to reduce the swelling and inflammation in and around the eye. There are some eye drops for animals that contain cortisone, which should never be used when an animal has corneal ulceration. It is really important that you don’t just get drops from a friend whose animal had an eye condition and start putting that your animal’s eyes. Similarly, you should also not use just any human eye drops, as this medication may be contra-indicated. In South Africa, as a result of the pet population being significantly smaller than the USA or European markets, some pharmaceutical companies do not register their products here. This means that in some instances, the vet may have to rely on a human medication. This is called extra label use, and the vet will take care to use a product that is compatible with your pet.

Antibiotic eye drops are only active for a few hours and as such need to be applied often. Depending on the severity of the ulcer, this can be from every hour to every four hours. Other eye drops, such as Atropine eye drops are active for much longer and usually only need to be applied once or twice a day. The vet will give you proper instructions as to how often to use the medicine prescribed.

It is important to continue treatment as per the veterinarian’s recommendations and not discontinue treatment too early, even if you see improvement. Speak to the vet if you are unsure.

The vet will most likely demonstrate to you how to apply the eye drops during the consultation for the eye problem and ensure you are comfortable applying them yourself before you go home.

The vet may advise on the use of an Elizabethan collar, known as the ‘cone of shame’, to prevent your pet from scratching and doing more damage to an already injured eye. This prevents paws and sharp nails from reaching the eye and is recommended until treatment is complete or the pain is under control.

Will my pet need another visit after treatment has started?

Yes, most vets require a check-up one week after treatment is started unless an earlier one is needed. This is to re-stain the eye to monitor the progress of healing. Pet owners must keep a close eye on injured eyes. If your pet’s eye seems more painful or if a pus-like discharge develops, rather see the vet sooner.

Most ulcers and erosions heal quickly while others require a bit more time. If there is minimal improvement after two weeks, the vet may advise on additional treatments or surgery. Depending on the case, you may be referred to a veterinary eye specialist.

Can eye drops have negative side effects?

There may be negative side effects, but this occurs rarely. If your pet is sensitive to an ingredient in the eye drops, you may see a marked response of swelling and irritation around the eye. If your pet’s eye appears more angry and painful after the eye drops than before, stop using them and speak to your veterinarian about an alternative.

Atropine eye drops if prescribed will cause the pupil to dilate in the eye in which it is applied. This is a normal and expected response. This also means that the eye is more sensitive to light and your pet may squint when in bright light.

You may notice that your pet salivates a bit more after application of eye drops, especially cats. This is because eye drops are bitter and may drain into the sinuses and sometimes into the back of the throat. This is not an allergic reaction, but rather the response to tasting the bitter eye drops.

If ever your pet keeps their eyes half or totally closed when not sleeping, get them to the vet sooner rather than later as a deep corneal ulcer can destroy the eye.

References:

Corneal Ulcers in Dogs by Ernest Ward, DVM, https://vcahospitals.com/know-your-pet/corneal-ulcers-in-dogs. Viewed on 29 September 2020.

Corneal Ulcers and Erosions in Dogs and Cats by Wendy Brooks, DVM, DABVP, reviewed 10 Oct 2018, https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951434 viewed on 29 September 2020.

My Collie is bumping into things and seems to have difficulty with its eye sight

What is Collie eye anomaly?

Collie Eye Anomaly is an inherited condition affecting both eyes of many different Collie type breeds of dogs. Interesting to note, that not only Collie breeds are affected but also some other breeds. Affected breeds include Rough and Smooth Collies, the Shetland Sheepdog, the Australian Shepherd, the Border Collie, the Lancashire Heeler, and the Nova Scotia Duck Tolling Retriever.

The region of the eye affected by this genetic condition is called the choroid. The choroid is the layers of blood vessels and pigment between the sensory membrane that lines the inner surface of the back of the eyeball (the retina) and the outer white covering of the eye (the sclera). The locations of all the parts being described can be seen in the image below.

The primary lesion is typically the underdevelopment of the choroid called hypoplasia, which results in the appearance of a pale spot on the back surface of the eye when looking through the pupil. More severe consequences may occur such as retinal detachment or bleeding in the eye, both of which may lead to blindness. The back part of the eye where the main nerve that runs from the brain the eye comes into the eye is called the optic disc. With Collie Eye Anomaly one will often find small areas of indentations next to the optic disc. These indentations look like holes in the structure of the eye and are also described as colobomas. The degree to which an individual animal may be affected varies considerably, from very mild, to severe enough that eyesight may be lost completely. The lesions are not progressive and normally do not worsen over time. Mildly affected dogs will just have the pale spot seen on the side of the optic disc. There will be no impact on the dog’s ability to see and the pale spots may be seen in very young puppies and not in adults. The choroidal blood vessels may be reduced in number and abnormal in shape. Up to 25% of dogs that are severely affected will have severe complications that result in significant vision loss. These include the retinal detachment (loosening of the membrane at the back of the eye), bleeding (ocular haemorrhage) and colobomas. This can happen in these severely affected dogs before two years of age and the severity in both eyes may differ. It is very rare for only one eye to be affected by this condition Although this condition does affect vision, it is fairly rare for a dog to be completely blind in both eyes.

How does a dog get Collie Eye Anomaly?

Collie Eye Anomaly is a fairly common condition in affected breeds that has its roots in breeding with affected animals who have not been identified as carriers of the genetic defect responsible. The single most important fact to remember is that Collie Eye Anomaly is genetic and all affected dogs can pass the disorder on to their offspring. It is therefore essential that regardless of the severity of the condition in any individual dog, that they should not be used for breeding. All dogs from affected breeds should be clinically examined and genetically tested before breeding to avoid this unwanted condition to be passed onto their offspring.

How is Collie Eye Anomaly diagnosed?

Diagnosis of this condition is generally confirmed through an ophthalmic (eye) examination by a veterinary eye specialist (veterinary ophthalmologist). The back of the eye is examined through an ophthalmoscope and an area of pallor is identified. This may be done from as early as 5 – 8 weeks of age. As the puppy grows, the retina becomes more pigmented and this may mask the changes in the choroid which means that the eye exam at an older age may appear to be normal, yet the dog still has the condition and is still a carrier of the gene which causes this condition. It is for this reason that all puppies must be examined at a young age, especially if they may be used for breeding later in life. Another fact to understand is that even a mildly affected dog may produce offspring that can be severely affected.

There is also a genetic test available that may be used by vets and breeders to avoid transmission of the disease to the next generation.

How does Collie Eye Anomaly spread?

Having established that Collie Eye Anomaly is a genetic condition where the structure of gene changes (known as a mutation), fortunately, the gene mutation responsible for the defect has been identified. This mutation is found on chromosome 37 on dogs. This is a recessive mutation. A recessive gene is a gene that can be masked by a dominant gene. To have a trait that is expressed by a recessive gene, both parents must pass on the mutated chromosome for the condition to be clinically apparent.

How is Collie Eye Anomaly treated?

Unfortunately, there is no treatment for Collie Eye Anomaly. The best way to prevent this in our dogs is to take part in conscientious responsible breeding, testing all animal from a young age and only breeding with dogs that are negative for both clinical signs and absent genetic mutation. This is our only weapon in the battle against a condition that can be very debilitating to affected pets and it is our responsibility to ensure we aim to breed for the health of our dogs above any other trait that may be deemed desirable.

What is the prognosis if my dog is diagnosed with Collie Eye Anomaly?

The prognosis of Collie Eye Anomaly depends on the extent to which the individual dog is affected. The condition does not normally progress however in early severe cases the indentations (colobomas) around the optic disc where the eye nerve enters the eye from the brain may lead to retinal detachment, which will make the condition severe at an early stage and lead to complete blindness which may lead to euthanasia. If the condition is not so severe and there is partial loss of sight, the dog will learn to cope with the partial loss of sight and will be able to live a good quality life.

Conclusion

It is very important to have any Collie type breed dogs tested for this Collie Eye Anomaly at a very young age (between 6 and 8 weeks of age), so if you do get a puppy that falls in this category of breeds, speak to the vet to set up an appointment with a veterinary eye specialist, to have the test done. A more ideal situation would be to request a certificate from the breeder that you obtain your puppy from, issued by a veterinary ophthalmologist, confirming that the necessary examination and tests have been performed and that the puppy you are obtaining does not have Collie Eye Anomaly.

My cat’s eyes are swollen and teary

What is conjunctivitis?

Conjunctivitis is the inflammation of the conjunctiva. The conjunctiva is the thin semi-transparent mucous membrane lining the inside of the eyelids, covering the third eyelid. This membrane attaches to the globe of the eye at the level of the sclera (the white part of the eye). The back end of the word conjunctivitis (– itis) refers to inflammation which is a defense mechanism of the body and means swelling, redness, increased heat to the local area because of an increase in blood flow to the affected area, and pain or discomfort. Conjunctivitis is a very common condition affecting our household cats.

What causes conjunctivitis?

This condition is typically caused by infectious organisms such as viruses like Feline Herpes Virus or Feline rhinotracheitis virus or bacteria such as Chlamydophila Felis or Mycoplasma. Other causes can include trauma to the eye which most cats typically sustain through cat fights, immune-mediated conditions where the body overreacts to a stimulus and ends up causing more damage to itself, or sun damage especially in white cats with unpigmented eyelid margins. Infectious causes of conjunctivitis are the most common and are important to treat, but more importantly prevent, as the infection may spread from one cat to another. Infectious conjunctivitis is usually a condition affecting younger cats. Cats that may be at increased risk for infectious conjunctivitis include those that live in multi-cat households, cats taken to the kennels or a cattery, cats exposed to other sick animals at the vet, or free-roaming cats that come into contact with all the neighbourhood’s cats. Another risk factor for this condition is the presence of an underlying immunosuppressive condition such as FeLV (Feline leukemia virus) or FIV (Feline Aids) which predisposes affected cats to these infections due to their reduced ability to fight off infections.

Cancer of the conjunctiva more commonly affect older cats, typically cats with no pigment in their eyelid margins. Their eyelids are effectively sunburnt and the process starts off with inflammation of the eyelids causing conjunctivitis, and eventually progresses to full blown cancer. If sun exposure can be restricted or contained, this condition can be prevented.

What are the clinical symptoms of conjunctivitis?

Clinical signs may vary in degree and affect one or both eyes. Your cat may have painful red eyes, some discharge from the eye which may be either watery or pussy in later stages of the disease, and in severe cases the eye may even be closed due to excessive swelling of the conjunctiva. These signs may be recurrent and vary with severity during the course of the disease. With infectious causes such as viruses there are often signs and symptoms of other upper respiratory tract infections such as sneezing, discharge from the nose and a loss of appetite partly due to a loss of smell.

How is conjunctivitis diagnosed?

Conjunctivitis is diagnosed by the veterinarian carefully examining the eye and all its adjacent structures and looking at all the different parts of the eye. What vets often look for is the presence of red inflamed conjunctiva, discharge from the eyes, signs of trauma or potential causes of the inflammation. If a cat with conjunctivitis is presented to the vet, the vet may do certain tests to check other parts of the eye such as the cornea, tear duct function and even eyeball pressure. This is important to rule other eye conditions which also have conjunctivitis as a symptom, but requires a completely different approach to treatment. These tests include a fluorescein dye test, where a luminescent green dye is applied to check for any defects or ulcerations of the cornea (the glassy clear layer on the front of the eyeball through which the animal looks). Another test is the Schirmer tear test that checks the tear production and determines if your pet suffers from dry eye. Lastly, the vet may want to test the eye’s pressure to determine if glaucoma may be present. Glaucoma is a condition of increased pressure within the eyeball, causing gradual loss of sight. On some occasions, if treatment is not working, more in-depth procedures such as blood tests, biopsies and conjunctival samples for bacterial growth may be necessary to determine the underlying cause of the conjunctivitis.

How is conjunctivitis treated?

The treatment goals for any case of conjunctivitis in cats include treating the underlying cause, eliminating infection (if present/possible), and reducing pain and discomfort. If there is an underlying cause that has been identified, this will be treated. Generally the treatment entails eye drops that need to be given at home according to the vet’s instructions. On this note something many of us are guilty of is trying to self medicate our cats with human over the counter eye drops. This is not a good idea as some human medications are contra-indicated in cats and by using the wrong medication we can actually do harm and make the condition worse. Always seek the advice of the vet before applying any medication. This also applies to eye drops prescribed by the vet previously or to another animal in the house hold. If the eye medication contains cortisone and there is ulceration on the cornea, it will only worsen the ulcer and your animal may lose its eye.

What is the prognosis if my cat has conjunctivitis?

The prognosis of conjunctivitis is generally good but depending on the cause of the conjunctivitis, certain complications may arise. Infection with herpes virus may lead to a corneal sequestrum, symblepharon (partial or complete adhesion of the eyelid conjunctiva to the eyeball conjunctiva), or dry eye. These conditions are permanent and the cat will never recover fully if complications like these arise. Conjunctivitis may be recurrent or chronic in some cases of infections. Because cats with herpes virus are often chronic carriers it is important to reduce stress in the environment as that is often the trigger for recurrent infections. Cats with underlying Feline Leukemia Virus (FeLV) or Feline Aids Virus (FIV) cannot be cured and because of their compromised immune systems, will always be prone to complications. Because of the recurrent nature of conjunctivitis in certain cats please do not lose faith in the vet or his or her ability to treat your cat. Work with the vet to understand the specifics of your cat’s condition and if the condition cannot be cured with a once off treatment, work out a strategy with the vet to manage the condition as effectively as possible. As with all medical conditions in pets, the sooner you attend to the problem once you notice any symptoms of conjunctivitis in your cat, the higher the likelihood of success with treatment. Don’t leave it till the cat can hardly see from its eyes and only then try and do something about it.

Is there a way to prevent conjunctivitis in my cat?

The answer is an unequivocal YES! By far the most effective way to prevent your cat from getting conjunctivitis is to have it vaccinated at the correct intervals and with the correct vaccines to prevent the upper respiratory tract diseases collectively known as “Snuffles”. Is it fool proof and will vaccination definitely prevent your cat from contracting these diseases? The answer is no. Sometimes viruses mutate or different strains infect your animal to what was in the vaccine. Does this mean that vaccinating is “fighting a losing battle”? Not at all. Having your cat vaccinated is certainly the best way to prevent disease, but does not guarantee that they won’t get infected. Making plans with cats who roam and land up in fights is a tough task, but can be done when there is a will to do so. Keeping cats with unpigmented eyelids indoors and out of the sun, is also a tough task because cats are by nature so inquisitive. Yet, if is means a better quality of life, cancer free, it is a small price to pay. Discuss your cat’s particular circumstances with the vet and find a solution with professional help.

There is something wrong with my dog’s eyes

What is “dry eye?”

Keratocunjunctivitis Sicca (KCS) or dry eye as it is commonly known, is a condition found in humans and animals where the eyes do not produce enough tears or moisture for the eyeballs to stay moist and shiny.

Which animals are prone to dry eye?

The condition is common in dogs and rare in cats. Cats who do suffer from the condition tend to show fewer symptoms of eye problems than dogs. Certain dog breeds are predisposed which include Cocker Spaniels, Bulldogs, West Highland White Terriers, Lhasa Apsos and Shih Tzus.

What are the symptoms of dry eye?

The symptoms associated with the condition can vary and are not necessarily very specific. This is why the owner of a pet with dry eye will realise there is something wrong with the dog’s eyes, but they cannot exactly describe what it is. The typical symptoms which one may notice vary and may include a combination of redness and swelling up of the inside of the eyelids (called chemosis), redness of the sclera (the white part of the eye next to the front “see through” (cornea) part of the eye), a discharge in the corner of the eyes, eyelids which are half open or sometimes closed tightly (blepharospasm), the third eyelids starting to move over the eyeball from the inside corner of the eye. Humans with this condition will tell you that it feels like there is sand in their eyes. One can imagine that if there is not sufficient moisture or tears to lubricate the eyeballs that the movement of the eyelids over the eyeball becomes strained every time the animal blinks. In bad cases which have been going for a while, the dryness on the eyeball can cause ulcers to start forming on the cornea with tiny blood vessels starting to appear on the shiny “see through” front part of the eyeball, the cornea. In severe cases, dry eye can lead to loss of vision and partial blindness.

Causes of and risk factors for dry eye

There are a wide range of reasons, conditions and external causes which can lead to dry eye.

Immunologic – Diseases, where the immunity of the animal is compromised or excessively challenged in one way or another, can lead to dry eye. One example is Atopic Dermatitis. This is an allergic skin condition often brought on by the inhalation of allergens like pollens (similar to hay fever in humans), which causes overall itching and scratching with areas of the skin being irritated and red and inflamed.

Congenital – A condition an animal is born with, with certain breeds like Pugs and Yorkshire Terriers more commonly affected.

Neurogenic – occasionally seen after trauma to the face like bite wounds or a car accident where the nerves supplying the tear gland or lacrimal gland are damaged.

Drug or procedure induced – Atropine which is a drug sometimes used to expand the iris so a proper eye exam of the back of the eye (the retina) can be performed will sometimes lead to a transient dry eye. In time this should clear up with no medication required. The same thing can happen when an animal is given a general anaesthetic (GA) and the vet forgets to put an ointment in the eye to cover the cornea, whilst they are doing a medical or surgical procedure. Most people do not realise that animals who are under general anaesthesia sleep with their eyes open. If dry eye happens because of a GA, it will usually clear up by itself a few days later.

Drug toxicity – One group of antibiotics called potentiated sulphonamides have been known to

cause transient or permanent dry eye.

Iatrogenic – Iatrogenic refers to an illness which is brought on by human intervention, typically a medical examination or treatment. The most common cause in dogs will be the removal of the third eyelid or membrana nictitans. There is a condition where this third eyelid starts moving over the eye and only in very exceptional circumstances should this third eyelid ever be removed.

Radiotherapy – Cancer of the eyelids is common in animals with white skin or low pigment in their skin. The treatment of this cancer may require radiotherapy where the beam needs to be aimed at the eyelids with the result that the eye itself is being radiated as well and this can lead to dry eye.

Chronic conjunctivitis – An inflammation with redness and swelling of the eyelids. This condition is more common in cats who suffer from chronic herpes or chlamydia infection.

Can dry eye be confused with other conditions of the eye or the eyelids?

Yes indeed. Dry eye can often be confused with bacterial conjunctivitis. The reason for this is that dry eye will often lead to a situation where there is a secondary overgrowth of bacteria because of the compromised situation of the eye and eyelids. The secret to differentiate lies in the diagnosis which is discussed below.

How is dry eye diagnosed?

Dry eye is diagnosed with the Schirmer tear test. The Schirmer tear test is a simple procedure where a small piece of special absorbable paper is bent over on the one side and hooked on to the lower eyelid of the animal. The rate at which the paper gets wet and the moisture moves down on the piece of paper determines whether enough tears are formed to keep the eye wet. Usually, the paper needs to get wet at the rate of 14 mm per minute. If this does not happen and the paper only gets wet too for instance 5 mm within a minute, it confirms a diagnosis of dry eye.

Other diagnostic tests which the vet may want to perform are fluorescein staining where a bright orange fluid is dropped onto the eyeball. If there is an ulcer on the cornea (which often happens with dry eye) the colour will turn a bright green. If an ultraviolet light is shown onto it, it will turn even brighter and “fluoresce”. The vet may want to take a swab of the eye to do a culture and antibiogram in cases where treatment seems to be unsuccessful. The vet may also want to do a cytobrush test where a tiny “roller brush” is rolled onto the inside of the eyelids, smeared onto a microscope slide, and examined under a microscope. The diagnostic tests done will depend on the particular circumstances of each individual animal suspected to be suffering from dry eye.

How is dry eye treated?

Animals with a confirmed diagnosis of dry eye are usually treated as outpatients. The eyes have to be cleaned before the medication is administered. Owners are usually instructed to keep the eyes and the area around the eyes as clean as possible on an ongoing basis. This is usually done with wiping the eyelids with cotton wool or cloth moistened with lukewarm water or a saline solution. If the animal seems to be developing more pain as the treatment goes on, it is important to get such an animal back to the vet as soon as possible because animals with dry eye are predisposed to severe corneal ulceration if not attended to. In previous decades, before more modern and effective medication was available to treat dry eye a surgical procedure was done were the parotid duct, a small duct which transports saliva from the salivary glands to the back of the mouth, was surgically redirected to the corner of the eye. For lack of anything else this procedure did help to some degree but the saliva tended to be irritating to the cornea and some animals were always uncomfortable after surgery. Fortunately, there are great and effective drugs available to treat this condition today and the two most commonly used medications which stimulate the eye to produce tears are Cyclosporin and Tacrolimus. The vet will assist you in choosing the right option for your pet.

Prognosis for dry eye

Depending on the cause of dry eye, the outcome of treatment is usually very positive these days with the drugs available to help stimulate tear production for the eye. If there are no other conditions like ulceration of the eye, complicating the treatment, animals with dry eye can live good quality lives until they die but will most likely require life long treatment and regular veterinary checkups.

If you are not sure if your dog who seems to have an eye problem has dry eye, bring him or her to the vet for a checkup and have the correct diagnosis made and correct treatment recommended.

My dog has what looks like a red cherry stuck in the corner of its eye

Introduction to cherry eye

A cherry eye is a non-life-threatening condition that occurs in dogs, and less often in some cat breeds. It is an extremely descriptive term, as one can see an oval, bright red swelling in the inside corner of an affected dog’s or cat’s eye, resembling a cherry. As a pet owner one can easily become quite alarmed by seeing this, but fortunately, it only causes slight irritation to the dog initially and you will have time to attend to it and take your animal to the vet before the condition gets out of hand. It is never a good idea to just leave it be. The condition tends to occur more commonly in younger dogs and cats, usually between the ages of 2 and 6 years.

How does it happen that an animal develops a cherry eye?

A cherry eye is in actual fact a protrusion (or bulging out) of the gland of what is colloquially called the third eyelid. Dogs and cats have three eyelids, the top and bottom lids that close up and down over the eyeball as in humans, and then a third eyelid, otherwise called the nictitating membrane underneath the upper and lower eyelids. If you press on the eyeball through the upper eyelid, you will notice the third eyelid moving across the ball of the eye from the inside corner of the eye towards the outside corner of the eye. This eyelid contains a gland that produces up to 30% of the tear production of the eye. The third eyelid provides extra protection to the animal’s eye and keeps the eye moist. The gland in the nictitating membrane is anchored to the corner of the eye by a connective tissue band. For reasons unknown, this connective tissue starts to weaken and the gland slips out of its pocket. If this happens, the gland is exposed to sun, wind, dust, and trauma from the outside. The gland becomes red and swollen, and eventually painful, due to inflammation. One or both eyes may be affected at the same time. The most common breeds affected by this condition are Beagles, Bulldogs, Spaniels, Shih Tzus, Pekingese, and other brachiocephalic (flat-faced) breeds. The condition is rare in cats but Burmese and Persians seem to have a higher incidence of cherry eye.

Other clinical signs associated with cherry eye.

You will quickly notice the red swelling in the corner of your animal’s eye. Other signs that you might notice are a mucoid discharge from the eye and/or redness in the tissue surrounding the eye, called conjunctivitis. Your pet might also show you he/she is experiencing discomfort by pawing at the eye or rubbing his/her face against objects. This can cause even more trauma to the exposed gland.

Course of action with cherry eye

Due to the fact that some dogs don’t seem phased by the popped out gland, some owners might opt to leave it like that. Not treating the gland may however cause more serious problems to the affected eye in years to come. As more damage is inflicted onto the popped out gland, the amount and quality of tear film that protects the eye will decrease causing chronic inflammation and irritation to the eye. The best would be to get treatment of the infected cornea eye as soon as possible. The vet will examine the eye closely and will usually recommend replacing the gland surgically. The vet may stain the cornea with a fluorescein stain to check for ulcers on the eye itself that might have occurred during protrusion of the gland. A few decades ago, it was common practice to remove the gland surgically when it protruded. This is not the practice any longer because by removing a gland that produces tears, the affected eye can dry out causing a condition called keratoconjunctivitis sicca, or more commonly referred to as ‘dry eye’. It is therefore no longer recommended to remove the gland surgically, unless the gland is so traumatised that it will lose its function in any case. Replacing the gland into its original position is usually done under general anaesthesia by anchoring the gland in its pocket with suture material. For an experienced veterinary surgeon it is a relatively easy surgical procedure to perform. The most common complication is a re-occurrence of the cherry eye and trauma to the cornea by suture. If the condition re-occurs it certainly does not mean that the vet did a hopeless job. Between 5 and 20% of dogs have a recurrence of the condition after the surgery. The reason is that the gland can protrude and prolapse to the other side where the sutures were not placed. If it happens the procedure just has to be repeated. There is no way of predicting whether your pet will be one of the unlucky ones where the condition recurs after the initial surgery.

Conclusion

It is not clear why the connective tissue of the third eyelid housing the tear gland weakens causing a cherry eye other than that there seems to be hereditary component. It is therefore not recommended to breed with affected dogs. Taking your dog to be examined by the vet as soon as you see the signs of cherry eye, can save you a whole lot of problems with your pet’s eyes later in his/her life, and even save his or her eyesight.

My pet injured its eye!

Just like in people, the eye of a dog or cat is a delicate structure that can be affected by a huge number of different conditions. This article will cover trauma to the eyelids, third eyelid and cornea.

Anatomy of dogs and cats eyes

The eye of the dog and cat is very similar in structure to the human eye but there are one or two differences. Both a cat and dog’s eye is globoid (round) in shape. The part of the eye exposed to the outside is protected by the eyelids and eyelashes, just as in people. The cornea is the see-through part of the eye. It is a thin layer, allowing light to pass through the pupil and lens to the back of the eye. The white of the eye is known as the sclera. The conjunctiva is the pink part of the eye that can be seen between the eyelids and the eyeball. Dogs and cats both have an extra membrane, known as the third eyelid or nictitating membrane. This membrane can be seen in the inner angle of the eye and sometimes it can cover most of the eye, particularly following trauma.

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Trauma to the eyelids

The eyelids are the first structures protecting the delicate eyeball from the outside and potentially trauma. Due to being more active, getting into fights and exploring, cats and dogs are more prone to traumatizing their eyelids. Lacerations or cuts to the eyelids are a fairly common injury seen in most veterinary practices. If there is any trauma to the eye, it is important to take your pet to the vet. Some injuries may be superficial and cleaning the wound with disinfectant may be all that is required. In other cases, the eyelid may need to be stitched back together. The sooner the eyelid is stitched, the better the chances of it staying together. It is very important that the eyelid margin (that is the part that the eyelashes attach to) remains smooth. If there is a kink in the eyelid margin, this can lead to further trauma to the eye and it can damage to the sensitive cornea. Once the eyelid has been stitched, your pet may require eye drops for a few days to assist with the healing and prevent any infection.

Trauma to the third eyelid

Sometimes the third eyelid can be lacerated. This is commonly seen in cats that have been involved in a fight and have been scratched in the eye. If the third eyelid is badly traumatized, it may need to be sutured.

Trauma to the cornea

Corneal ulcers

The most common injury seen to the cornea is corneal ulceration. This is where the first outer layer of the cornea (the epithelium) is damaged, exposing the more sensitive inner stroma of the cornea. This can be very painful. A scratch to the eye or a splash of shampoo or other caustic substances can cause an ulcer. There are some viruses, such as herpes virus in cats that can also cause ulcers in the cornea. Often we do not know what has caused the ulcer. If you notice your dog or cat squinting, or the eye is closed and seems painful, then it is important to take them to the vet immediately. Often the conjunctiva will also be inflamed. This is known as conjunctivitis. The eye may also have some discharge.

The vet will examine the eye with an ophthalmoscope. This will allow the inside of the eye to be seen and ensure that there is nothing else going on. The vet will then perform a fluorescein test. This is where an orange stain is placed on the cornea. The eye is then looked at with a UV light (blue coloured light). If there is any defect in the cornea, this will show up as bright green. The corneal epithelium does not take up any stain but if the stroma is exposed it will take up the stain.

Corneal ulcers can vary in size and severity. It is important to start treatment as soon as possible as the quicker it is treated, the more likely it is to heal. If the injury is superficial and small topical treatment with eye drops remains the most effective treatment. It is important that eye drops containing corticosteroids are not used as this delays the healing of the cornea and can, in fact, make the ulcer worse. Other drops and medications may be needed for pain control or to maintain the eye’s lubrication. The eye will need to be assessed daily to ensure that it is healing. In some cases, further treatment will be needed. In severe cases, the ulcer may need to be covered with either the third eyelid or some conjunctiva. This procedure will need to be done under general anaesthetic. The flap is placed over the cornea and sutured in place to give the cornea time to heal. The vet may even give you a referral to a specialist veterinary ophthalmologist which is a vet who would have done between four and six years of extra study over and above their veterinary degree, to become an eye specialist.

There is no set time to how long the cornea will take to heal but daily checkups are required initially to ensure that the condition is not deteriorating. In very severe or long-standing cases, the eye may even need to be removed.

Foreign bodies within the eye

Penetration of the cornea by foreign bodies such as thorns, glass and sand can be seen in dogs and cats. This is normally very painful and can quickly lead to infection within the eye. If the foreign body is just penetrating the surface of the cornea, it may be removed with the aid of local anaesthetic. In severe cases, where the foreign body has penetrated deeper into the cornea and eye, it will need to be surgically removed. Fine instruments are often required in order not to damage the eye further and this procedure may need to be performed by a specialist ophthalmologist. If your pet is showing any signs of pain or discharge to their eye, it is important to seek immediate veterinary attention.

What is the prognosis with eyelid and corneal trauma?

The prognosis of injuries to the eyelids and cornea will depend on the severity of the trauma. If treated quickly, then permanent damage to the eye is minimized but this does depend on how extensive the injury is. The cornea scars white and so if the ulcer is very deep or long-standing this can affect the eyesight, particularly if the scar forms over the part of the cornea that is in front of the pupil. It is important to remember that the quicker it is treated, the more successful the treatment is likely to be. If you notice any pain, discharge or redness to your pet’s eye, it is important to take them to vet for an assessment. You may ask how do you determine that your pet experiences pain in their eyes? Apart from you visibly seeing damage to the eye or noticing an eye which is excessively teary, you will most likely notice your pet scratching at the injures eye with their front paw or alternative scratching the eye or face on furniture or the carpet, in an effort to relieve the discomfort and pain. If you are in doubt, err on the conservative side and get your pet to the vet as soon as you can. The loss of eyesight through the loss of an eye is simply not worth risking seeing whether the animal will get better by themselves.

Proptosis

Proptosis is defined, as the forward displacement of the globe (eyeball) out of the socket, with the eyelids trapped behind the globe.

Proptosis is an ophthalmic emergency. Any suspected trauma to your pet’s eye warrants a visit to your veterinarian immediately.

Let us first have a look at the normal eye anatomy:

Predisposing factors: Breed predisposition

Proptosis is a condition more commonly seen in Brachycephalic breeds (dogs with prominent bulging eyes, short noses and shallow eye sockets). Pekingese, Pug, Boston terrier and Shihtzu are over represented.

Common Causes

Trauma is the most common cause of proptosis. In small breed dogs this often occurs during a fight with a larger dog, wherein the larger dog bites over the scruff on the neck and starts shaking the smaller dog. The pulling of the skin back over the head allows for the eye to pop forward, out of the socket. Bite wounds directly to the face could also result in proptosis of one or both eyes but this is very rare.
- Blunt trauma to the face or head, often seen when hit by a car.
- Brachycephalic breeds have very shallow eye sockets, and very large openings of the eyelids, in these breeds even mild manual restraint can result in proptosis.
- Space occupying lesions behind the globe e.g. tumours located behind the eyeball, applying pressure and pushing the globe forward.

Clinical signs

Often the first thing noticed by owners is a very prominent eye where the eyelids are unable to blink over the eyeball (globe).

Other signs include:

Swelling and inflammation of the tissue/muscles surrounding the proptosed globe
Bleeding inside the eye
Abnormal pupil (it may be dilated or constricted)
Rupture of the globe
Rupture of the muscles around the globe, the eye then deviates outward. These muscles are responsible for keeping the globe in place and are responsible for movement of the eye.

Proptosis needs to be distinguished from

Bupthalmia: Enlargement of the eyeball (globe), often caused by Glaucoma or a tumour in the eye.
Exopthalmia: Abnormal protrusion of the globe forward, the size of the eyeball remains normal it is just the positioning that changes. Often caused by tumours behind the globe, abcesses in the tissues surrounding the eye or bleeding behind the globe.

What to do when you notice your pet’s eye has proptosed?

Keep the proptosed eye moist. You can use lubricating human eye drops, or sterile water, try not to use tap water as tap water contains micro-organisms which can be detrimental to eye health.
If you have an old Elizabethan collar you should put it on your dog as a proptosed eye is very painfull and your dog will try to rub it or scratch at it using its paw. The Elizabethan collar will therefore aid in limiting further trauma to the proptosed eye.
Do not give your pet any human pain medication or anti-inflammatories, your vet will treat it as soon as it arrives at the practice with the correct medication at the correct dosage.

Presentation to the vet

Your pet will be assessed for any other injuries or possible complications; this is a very important step especially if the cause of the proptosis was an accidental hit by car. The patient must be stable before any surgery can be attempted.

The vet will then examine both eyes to assess the extent of injury.

The vet will look at the cornea (thin see-through layer) by staining it with fourecein to determine if there are any cuts or scratches on the surface of the eye (this stain changes color from orange to green if there are any cuts or scratches on the cornea). Then also the muscles, skin and nerves (optic nerve) attached to the eye will be examined

Based on the severity of the injury two treatment options exist, either replacement of the eye back into the socket or enucleation (surgical removal of the proptosed eye).

The prognosis for vision in the affected eye is always poor and is often dependant on the extent of the trauma to the eye and how soon treatment is started. Even if vision is lost, rapid response could aid in salvaging the eye for cosmetic reasons.

When the patient is stable enough they are placed under general anesthesia.

If the eye can be salvaged it is lubricated and placed back into the eye socket. Sometimes an incision is made on the outer edge of the eyelid to allow more space and make replacement of the eye easier. They eyelids are then stitched closed – this procedure is called a temporary tarsorrhaphy. Often times the vet will dispense eye drops that needs to be applied daily, this promotes healing of the cornea. The stitches are removed after two weeks and the function of the eye is reassessed to determine if the vision in the eye was affected or not.

If an enucleation is required, the globe is removed, blood vessels and nerves are tied-off and excessive tissue is also trimmed away. The eyelids are permanently stitched closed.

In both instances the patient is sent home with pain medication and an Elizabethan collar to prevent further trauma to the surgical site.

The thought of imagining a beloved pet with only one eye is very distressing and traumatic to owners, but most often these patients recover really quickly and do lead normal happy lives.