All Animal Eye Services: Eye Disease & Information
Cherry eye
Cherry eye occurs when the gland of the third eye lid has prolapsed. The third eyelid lies between the lower eyelid and the eye and is located at the inside corner of the eye. The purpose of the third eyelid is to protect the eye and to spread tears over the cornea (the clear window of the eye). The third eyelid contains a tear-producing gland that contributes up to 40% of overall lubrication of the eye.
The gland of the third eyelid lies within the third eyelid. The gland is wrapped around the cartilage core of the third eyelid and anchored in place by ligamentous attachments. Occasionally these attachments release along with a subtle kinking of the cartilage, which allows the gland to spring upward over the rim of the third eyelid. Because it is a deep red colour it is termed ‘cherry eye’. This condition is more common in some breeds than others, but any dog may develop the condition.
The prolapsed third eyelid gland should not be removed. If the condition is left untreated, the eye is at risk of developing dry eye months to years later. Additionally the prolapsed third eyelid gland can swell, be uncomfortable, and interfere with vision. However, while surgery decreases the chances that the eye will develop a dry eye problem, it does not eliminate this risk.
Medical treatment alone seldom rectifies the condition and surgery is often required to reposition the gland. A non-absorbable suture is used to place the gland into a pocket created in the third eyelid and anchor it in its normal place. We often place a temporary suture in the outer eyelids to hold them together and give additional support to the surgery. The success rate of surgery is approximately 90-95%, except in large breeds of dogs, in which the success rate is lower.
Collie eye anomaly
Collie Eye Anomaly (CEA) is a congenital under development of the choroid. We see pale areas at the back of the eye (called choroidal hypoplasia), pits (colobomas) in the optic nerve head and occasionally retinal haemorrhage and detachment. Not all CEA positive dogs show ALL these signs. Rough and Smooth Collies, Shetland Sheepdogs (Shelties), Australian Shepherds and Border Collies are the predominant breeds in which this condition is seen.
Heredity.
The mode of inheritance of CEA is very complex but it is believed to be recessively inherited. Carrier states do exist. Dogs carrying the gene may show no clinical signs on examination. When mating two clinically normal carrier dogs, approximately 25% of the offspring will be clinically affected, 50% will be carriers and 25% will be normal (and not carry the CEA gene or genes). It is a misconception to assume breeding mildly affected dogs will produce normal offspring - if the condition is present clinically, the dog is carrying the gene(s) for CEA.
Incidence.
Border Collies show an incidence of less than 5%. Rough and Smooth Collies have a reported incidence of 50-90%. One survey from Queensland found an incidence in Shelties of approximately 74%. Similarly, the incidence is high in the rest of Australia.
Loss of vision.
Poor vision is often difficult to detect especially if the CEA signs are mild. Owners report poor vision especially with large pits in the optic nerve head. Vision loss may occur if there is retinal haemorrhage and detachment.
Purchasing a puppy.
Puppies purchased for breeding purposes need to be checked by a veterinary eye specialist at approximately 6-8 weeks of age. This is the best time to check for choroidal hypoplasia. Colobomas are checked later, at around 14 weeks of age or later. After 14 weeks of age it is not possible to detect all cases of CEA. The development of retinal pigment can cover the signs of CEA. While the dog can appear normal (hence the term 'go normal'), it can still transmit the CEA gene(s).
Detection of carries by test mating.
Most Collies and Shelties with normal eyes are carriers. Test mating detects carriers, mildly affected dogs and 'go normals'. Test mating is the most efficient method of reducing the incidence of CEA. Mating clinically unaffected dogs will ultimately reduce the incidence of CEA in all types of Collies although not as rapidly as test mating.
Reducing CEA in your kennel.
1. In the ideal situation, it would be best to discard all affected dogs, their parents and progeny from your breeding program. It is not possible to be this radical, so start by not breeding from dogs affected by pits in the optic nerve head and choroidal hypoplasia combined.
2. Breeding from mildly affected dogs will NOT reduce the incidence of CEA but may reduce the severity of the condition in the progeny.
3. Test mate to detect carriers and 'go normals'. Note that mating an affected dog to a genetically clear dog will produce a litter of carriers.
4. Buy or breed only from dogs certified free of CEA by a veterinary eye specialist.
5. A genetic test is now available . Visit: www.gtg.com.au
Conjunctivitis
The conjunctiva is the mobile, elastic mucous membrane found lining the inside of the eyelids, both sides of the third eyelid and the exposed surface of the eye (except the cornea which is the clear window of the eye). The conjunctiva is a partly transparent pale pink colour. When the conjunctiva becomes inflamed (red and swollen) we use the term conjunctivitis. Conjunctivitis may be a localised disease or part of a disease involving the rest of the body. It is vital that a complete eye examination is performed. A "red eye" can mean more than just conjunctivitis.
Simple conjunctivitis is usually not a vision threatening or severely painful disease, but treatment is indicated to relieve discomfort and to prevent it getting worse. Conjunctivitis in the dog differs from the cat in that it is not usually spread to other dogs in contact. The most common cause in the dog is allergy. Some owners notice that their dog is generally itchy or has had recurrent ear disease at the time of diagnosis. Less commonly causes include viruses, fungal organisms, bacteria, parasites or foreign bodies.
Treatment usually consists of drops or ointments. Follow up visits are vital to ensure that treatment is resolving the conjunctivitis.
Long term uncontrolled conjunctivitis can to lead to more severe ocular diseases such as keratoconjunctivitis sicca (KCS or dry eye), entropion (rolled in eyelids), keratitis (inflammation of the cornea) and corneal scarring.
It is important to note that treatment of allergic conjunctivitis is aimed at the control of the allergic condition, rather than a cure. Some dogs may require plastic eyelid surgery if they have poor fitting eyelids. This surgery is aimed at correcting eyelid position, reducing conjunctival exposure and stabilizing the tear film.
Corneal Sequestration in cats
Feline corneal sequestration is a dramatic and unusual corneal disease unique to cats. It refers to the development of a dark brown to black plaque on the cornea, which is a dead piece of corneal tissue. A sequestrum is usually oval to round, can be small to quite large, and can extend deeply into the corneal tissue. Some sequestra have the appearance of a shiny piece of black patent leather on the surface of the eye. Others have a bronze appearance.
Corneal sequestration can occur in cats of all ages and breeds. The breed with the highest frequency of occurrence is the Persian breed. Other at-risk breeds include Siamese, Birman, and Himalayan.
This condition can be painful. The signs of ocular pain may be subtle and include squinting, tearing, and elevation of the third eyelid. A sequestrum can slough from the eye’s surface and cause eye rupture. If this occurs, the eye may need surgical removal (enucleation).
The exact cause of feline sequestra is unknown. However, the development of a sequestrum is often associated with corneal trauma, dry eye syndrome, abnormal eyelid conformation, and/or Feline Herpes Virus infection. Genetics and conformation may also be involved since there is a definite breed predisposition. A thorough ophthalmic examination is essential to uncover any underlying problems.
It is important to treat the corneal lesion as well as the suspected primary cause. Removal of the offending plaque by microsurgery is required. Surgery is performed under high magnification using very fine instruments. The resulting defect in the cornea is repaired with a conjunctival graft to provide the cornea with a blood supply and mechanical protection. This will reduce the likelihood of recurrence of the black plaque.
If the cause is a lid abnormality, plastic surgery techniques are also required to correct the eyelid position to reduce the irritation to the cornea. If FHV is the suspected primary cause, topical antiviral medication and oral lysine may be indicated. In cases occurring in flat-faced breeds, we advise that the eyelid openings be surgically reduced (canthoplasty). This is necessary as the proposed underlying problem is related to exposure and an inadequate tear film at the centre of the cornea and possibly rolling in of the inside of the lower lid (entropion). It is common for the opposite eye to be affected at a later stage so we usually advise that both eyelid openings be surgically shortened in an effort to reduce exposure and stabilise the tear film.
On occasions the lids will be temporarily stitched together to further protect the surgical site. The temporary stitch in the eyelid is removed after one week during your revisit.
The eye is usually free from pain and the cat will have useful vision after surgery, especially if the sequestrum is removed at an early stage. However, individual cats have a tendancy to form a sequestrum in response to corneal irritation and additional episodes may occur in one or both eyes in the future.
Corneal ulcerations
The cornea is the transparent layer or 'clear window' of the eye. It is less than 1 mm thick and consists of several complex layers. It is the most sensitive part of the eye and readily reacts to irritants or stimuli from outside the eye.
Corneal ulceration is a common eye disease caused by disruption to one or more layers of the cornea. Corneal ulceration can be caused by trauma, a foreign body abrasion, eyelid disease, extra eyelashes, inflammation, infection, poorly fitting eyelids, prominent eyes and dry eye (tear deficiency). It can be made markedly worse by unsupervised use of cortisone eye ointment or drops. Deep corneal ulcers can lead to eye rupture.
Signs.
Holding the eye closed, a cloudy eye, a watery eye, a mucky discharge from the eye and redness in the white part of the eye.
As a corneal ulcer deepens the pain may decrease and can be easily overlooked due to the reduced number of sensory nerve endings in the deeper layers of the cornea.
Management.
Some ulcers may take months to heal unless treated surgically. An operating microscope is needed for more sophisticated surgery.
Some forms of corneal ulceration may need to be repaired using a conjunctival graft or flaps. In these surgical procedures, the conjunctiva is moved onto the eye and stitched into or across the cornea. Occasionally a donor cornea or specialised materials are sutured into the ulcer to repair the cornea. Antibiotic drops or ointments and oral anti-inflammatory medication will be required after surgery.
BEWARE: Corneal ulceration that gets deeper is an emergency! Please call us immediately if you notice that the eye is being held closed, there is an increase in discharge from the eye or if the eye becomes red and cloudy.
Dry Eye - Keratoconjunctivitis (KCS)
Dry eye means the tear film is absent or inadequate. A dry eye often appears red with a mucky discharge. The surface of the eye (cornea) may appear dry without its normal gloss.
A healthy tear film on the eye is vital for eye health as the tear film provides nutrition to the surface of the eye. However a dry eye does not always look dry. A dry eye is usually diagnosed by tear tests. In the later stages there is a tenacious, mucopurulent discharge from the eye. Dry eyes cause extreme discomfort although the patient may show few signs of distress. Excessive blinking may be the only sign.
Causes: Systemic disease, distemper, feline herpes virus in kittens, immune mediated disease, sulpha drugs, trauma, prolonged conjunctivitis, removing the gland of the third eyelid (‘cherry eye'), infection in the eye socket and other inherited factors. In addition, the function of the tear gland decreases as animals get older so we tend to see many cases in older animals.
Breeds: Any breed may be affected, but dry eye is seen most commonly in West Highland White Terriers, Bull Terriers, British Bulldogs, Chihuahuas, Miniature Schnauzers, Dachshunds, Cocker Spaniels, Cavalier King Charles Spaniels, Pekingese, Yorkshire Terriers, Lhasa Apsos and Pugs.
Treatment:
Clean the eye using sterile saline solution and cotton wool twice daily.
Artificial tears - i-drop-VET (gold standard), Celluvisc or Luxyal.
Immune modulating medication - Optimmune ointment, Cyclosporin drops or Tacrolimus ointment. These drugs stimulate and restore tear gland function. They also reduce inflammation on the surface of the eye.
Microsurgery.
Plastic eyelid surgery (canthoplasty) is often recommended in severe cases to reduce corneal exposure, increase tear film stability and reduce evaporation of the tears.
If medical treatment fails to help, then the transposition of the parotid salivary duct from inside the mouth to the eye can give permanent relief. This delicate surgery is carried out under the operating microscope.
Complications without treatment.
If KCS is left untreated or uncontrolled, it can cause pain, ulceration, pigmentation and scarring of the cornea. Blindness is usually the result.
Extra lashes - Distichia and Ectopic Cilia
The eyelids of dogs and occasionally cats can grow abnormal hairs. These hairs grow from the oil glands (Meibomian glands) of the lids and are called distichia. The hair protrudes from the oil gland opening on the edge of the eyelid. Distichia are often irritating, especially if the hairs are stiff or bristly. Ectopic cilia are also hairs growing from oil glands on the eyelid, but the hair protrudes from the inner surface of the eyelid and is very painful, often causing corneal ulcers.
Breed predisposition for extra lashes occurs in many dog breeds. As the condition is believed to be inherited (in a dominant manner) breeding from affected dogs is generally not advised. The condition is seen more commonly in the Cocker Spaniel, Shetland Sheepdog, Poodle (Miniature and Toy), Miniature Schnauzer, Staffordshire Bull Terrier, British Bulldog, Boxer, Golden Retriever, Cavalier King Charles Spaniel and Pekingese.
Some soft lashes cause little harm, however minute stubby lashes identified under high magnification, may cause corneal ulceration and considerable pain. This is especially the case in the 'bristly' breeds such as the Staffordshire Bull Terrier, Boxer, British Bulldog and the Pug.
The extra lashes are removed under general anaesthetic using an operating microscope. There are several methods that can be used - either cryosurgery (freezing) or excision of the root of the extra eyelash through the conjunctiva on the inside of the eyelid.
Many lashes may remain within the glands and do not emerge until later so all potential lashes cannot be observed at one consultation. Some lashes fall out, only to grow again, just as our own eyelashes. Plucking the eyelashes tends to stimulate more rapid regrowth of extralashes.
As the roots of the extra eyelashes are removed at surgery (transconjunctival excision) or frozen, they will not grow back. Other lashes may emerge from neighbouring gland openings after the surgery. The surgery appears to 'awaken' dormant (resting) eyelashes. For this reason it is wise to expect further surgery. Depigmentation of the eyelid margins is possible after cryosurgery. This can some times be permanent.
Eyelid Tumors in Dogs
Older dogs commonly develop eyelid tumours. As in humans, tumours can be either benign or malignant (cancer). Fortunately, eyelid tumors in dogs are usually benign and do not spread to distant tissues. However, the growth of the eyelid tumour (slow or rapid) can destroy the structure of the eyelid. The eyelid tumour may also cause problems by rubbing on the cornea (clear window). It is usually best to remove the tumours when they are still small.
Eyelid tumours are treated by surgical removal. While there are many different surgical procedures possible, most eyelid tumors in old dogs are removed under general anesthesia. The tumour is removed and the site may be frozen (cryosurgery) to kill any remaining tumour cells. Tumour cells are usually very sensitive to freezing, and normal eyelid tissue is more resistant. After cryosurgery, the eyelid margin turns pink (depigments), but usually repigments within 4 months. It is rare for the eyelid tumor to recur following surgery (90% of tumours do not recur following surgery).
Systemic hypertension
Systemic hypertension is high blood pressure. High blood pressure is an important disease diagnosed in dogs and cats because it can cause serious organ damage and blindness. Blindness caused by systemic hypertension is usually associated with retinal detachment and/or bleeding within the eye. The normal blood pressure in dogs and cats is well below 160 mmHg. The recommended acceptable blood pressure threshold in dogs and cats in 165-170 mmHg. Treatment is usually commenced once you pet’s blood pressure exceeds 170 mmHg.
Causes of increased blood pressure
1. Kidney disease
The kidneys help regulate blood pressure. Renal disease is an important cause of high blood pressure in animals, especially cats. Clinical signs of kidney disease may include weight loss, increased thirst and increased urination. If we suspect your pet has renal disease, further diagnostic investigation will be recommended. This will usually include blood and urine tests and can be performed at your local veterinary clinic.
2. Endocrine (hormonal) disease
Diabetes mellitus, hyperadrenocorticism and hyperthyroidism may also be associated with high blood pressure in animals. If we suspect your pet has one of these diseases, further diagnostic investigation will be recommended. These usually include blood and urine tests and can be performed at your local veterinary clinic.
3. Cause unknown (idiopathic) or primary hypertension
This means no obvious cause can be found at the time systemic hypertension is first recognised. In many cases however, kidney or endocrine disease become evident some time after a diagnosis of systemic hypertension is made. Further diagnostic investigation will therefore be recommended. This will usually include blood and urine tests and can be performed at your local veterinary clinic.
Treatment
1. Oral medication
Oral medication(s) to control your pet’s blood pressure may be dispensed at the time of diagnosis of systemic hypertension. Examples include Norvasc and Fortekor. Medications are dispensed in tablet form and are usually administered once daily. Few side effects are recorded but periodic blood and urine test are usually necessary to detect are deterioration of underlying kidney disease.
2. Regular blood pressure measurement
High blood pressure can cause retinal detachments and haemorrhage within the eye. This can lead to permanent blindness in severe cases. It is therefore important we monitor your pet’s blood pressure regularly. In some cases this can be done at your local veterinary clinic. Regular ophthalmic examinations are also recommended because the earliest signs of elevated blood pressure can be detected during a routine retinal examination at consultation.
Prognosis
Generally speaking, when hypertension is detected and treatment is commenced early in the course of disease, the prognosis for long term vision is improved. Severe haemorrhage within the eye associated with retinal detachment usually carries a poor prognosis for a return of vision. In some cases vision may return after treatment commences only for it to deteriorate again months or years later.
Glaucoma
What is Glaucoma?
Glaucoma is increased pressure within the eye. Cells inside the eye produce a clear fluid (aqueous humor) that maintains the shape of the eye and nourishes the tissues inside the eye. The balance of fluid production and drainage is responsible for maintaining normal pressure within the eye. In glaucoma, the drain becomes blocked but the eye keeps producing fluid. Therefore, the pressure in the eye increases. The increased pressure in the eye can cause the eye to stretch and enlarge.
What causes Glaucoma?
Glaucoma in animals is classified as either primary or secondary.
Primary Glaucoma has an hereditary basis. Primary glaucoma occurs in many breeds, especially American Cocker Spaniels, Basset Hounds, Chow Chows, Shar Peis, Labrador Retrievers and Huskies. It is rare in cats but has been reported in the Burmese, Persian and Siamese.
Primary Glaucoma usually begins in one eye, but almost always eventually involves both eyes, leading to complete blindness.
Secondary Glaucoma occurs when other eye diseases cause glaucoma. Common causes of secondary glaucoma are inflammation inside the eye (uveitis), advanced cataracts, cancer in the eye, lens subluxation or luxation and chronic retinal detachment. Glaucoma in cats is usually secondary to uveitis.
Determining whether your pet has primary or secondary glaucoma is important because the treatment needed and the prognosis for vision is different for each type. Veterinary ophthalmologists use slit lamp biomicroscopy, indirect ophthalmoscopy and gonioscopy to determine the type and cause of glaucoma in your pet.
Gonioscopy helps determine how predisposed the remaining visual eye is to develop glaucoma when primary glaucoma is suspected. This test involves placing a special contact lens on the eye that allows examination of the drainage angle. Gonioscopy is usually performed under sedation or general anaesthesia.
How does glaucoma affect the eye?
Vision Loss. Pressure damage to the optic nerve and decreased blood flow to the retina, (nerve tissue at the back of the eye,) results in loss of vision. However, if the pressure in the eye remains uncontrolled, the retina degenerates and vision is permanently lost. Permanent blindness can occur within several hours if the pressure is very high and the glaucoma develops rapidly.
GLAUCOMA IS AN EXTREMELY PAINFUL CONDITION. IF YOUR PET IS DEPRESSED, RUBBING HIS/HER EYE(S) OR SLEEPING MORE THAN USUAL, THEY MAY HAVE GLAUCOMA.
Diagnosis.
The only way to know for sure if your pet has glaucoma is to measure the intraocular pressure with a special instrument called a tonometer. Signs of glaucoma can include a red eye, cloudy cornea and vision loss. However, loss of vision in one eye may not be obvious because animals compensate with their remaining eye. Eventually, the increased pressure will cause the eye to become enlarged. Unfortunately, eyes are usually permanently blind by the time they become enlarged. If your dog has lost one eye to primary glaucoma then the other eye is at risk of developing glaucoma.
How do we manage glaucoma?
Glaucoma is controllable rather than curable and often gets worse despite treatment. Eye drops may be prescribed to reduce the pressure in the eye. In some cases surgery may be available to relieve glaucoma. These procedures may include cryotherapy or laser surgery to slow the fluid production in the eye or placement of an intraocular drainage implant. Intrascleral prothesis or removal of the eye may be required in visually impaired and painful eyes.
Prevention.
Dogs with primary glaucoma should not be bred as the predisposition to the condition is inherited. At least some members of every family of breeding dogs should be checked by angle examination (gonioscopy). When one eye has primary glaucoma, the unaffected eye should be checked regularly and prophylactic therapy started. Prophylactic medical therapy for the remaining eye delays the onset of glaucoma from a median of 8 months to a median of 31 months.
Breeds affected by glaucoma
Lens Luxation
The crystalline lens is the fine focusing device of the eye. It is located just behind the iris (the coloured portion of the inside of the eye). When the eye is observed normally, the lens may not be visible unless it is diseased (cataracts). The lens is held in position by small fibres called zonules. These zonules (which are smaller than a human hair in diameter) attach the lens to the ciliary body, located behind the iris. The ciliary body produces the fluid contained in the chamber of the eye. Sitting behind the lens is the jelly of the eye or vitreous.
What is a luxated lens?
If the zonules holding the lens in position break, the lens can either partially (subluxation) or completely (luxation) dislocate. When the lens is luxated to the front of the eye it is called an anterior luxation. If the lens is luxated to the rear it is called a posterior luxation.
What causes the lens to loosen?
The most common causes of lens luxation or subluxation include:
1. An inherited weakness in the lens zonules seen commonly in terrier breeds.
2. Serious trauma to the eye.
3. Inflammation within the eye (uveitis).
4. Chronic (long standing) glaucoma (increased pressure within the eye)
5. Congenital (present at birth) defects within the eye.
What are the consequences of lens luxation?
An anterior lens luxation is a serious condition and considered an emergency.
This is because the anteriorly displaced lens interferes with normal flow of the fluid in the front of the eye. This often leads to glaucoma (increased pressure within the eye). Within 24-72 hours glaucoma causes irreversible damage to the nerve tissue at the back of the eye, and permanent blindness.
Other changes that can occur in the eye include corneal oedema (blueness of the normally clear window of the eye), corneal ulceration, uveitis (inflammation in the eye), and cataract formation.
What is the treatment for lens luxation?
Treatment depends on whether your pet has vision when the lens luxation or subluxation is diagnosed. Early lens removal is indicated in anterior lens luxation. This greatly reduces the chances of glaucoma developing after surgery.
Posterior lens luxation may be managed with medication initially. This will require you to keep a careful watch for any changes in the eye that may indicate the lens has displaced into the front chamber of the eye. These include:
1. Blue colouration of the normally clear window of the eye.
2. Redness in the white of the eye.
3. If the eye is closed.
4. If your pet is rubbing the eye.
5. Any excess watery discharge from the eye.
6. If your pet becomes depressed and begins to sleep more than normal.
What about a subluxated lens?
The treatment for a subluxated lens depends on whether the pressure within the eye is normal or increased (glaucoma). Frequent re-examination will be required in this situation to check for any changes in the eye indicating that the lens is moving. Medication is usually used daily to keep the lens in place and to prevent glaucoma in the eye.
What about the other eye?
Your pet will be examined to ascertain if the zonules are intact. If the lens appears to be loose due to hereditary causes, then we recommend the lens in the second eye be removed to prevent the consequences described above. If the lens appears normal, then regular check ups will be scheduled to assess the beginning of lens dislocation in the second eye.
Living with a pet with poor vision or blindness
When your pet bumps into things because of poor vision or blindness, he/she may require some extra training to enhance his/her quality of life. Be ready to teach your pet a few new ‘tricks'. Many pets will live a happy and fulfilling life once they have adjusted to a life with reduced vision or blindness.
Points to note when retraining a dog with poor vision or blindness.
You will find your pet wants to stick close to you when they become visually impaired or blind. Your pet’s other senses e.g. smell, touch and hearing, will be relied upon when your pet’s vision deteriorates. Build your pet’s confidence by talking to them. Raise the pitch of your voice when he/she approaches a hazard to alarm them of danger. Consider taking him/her to obedience classes. This will improve your communication with your pet and teach them to respond to your voice commands. It will also build your confidence in your pet’s amazing ability to live with reduced vision or blindness. A dog with poor vision should always be on a lead in public.
Use simple one word commands such as:
"UP" - a change in height, or step over an object,
"HERE" - come to the hand that is making the noise (slap the side of your leg or snap your fingers),
"STOP" or "STAY" – Your pet should stop and stay. The inflection of your voice offers a warning.
"NO" - hold your pet immobile while you emit a low growl followed by a firm "NO".
Your pet will respond to praise. NEVER criticise your pet, this will only heighten his/her anxiety and destroy their confidence. Finish each lesson on a positive note and use plenty of tasty treats such as Vet's Rewards™. A visually impaired or blind pet, with your support, can learn to function very well.
Mastering stairs.
Stairs are frightening for visually impaired and blind animals. They often find going up stairs far easier than going down. Your pet will probably need some training to learn to walk down stairs.
Take one step at a time and try using a treat to entice your pet down the stairs eg. a piece of Vet's Rewards™. Try counting the stairs out aloud, changing your tone as you count up or down - a sing/song technique is best. This way your pet can anticipate the top and bottom of the staircase. Placing incense oils, perfumes or fragrant pot plants at the top and bottom of the staircase will also assist your pet. You can also use these on objects your pet frequently bumps into, to warn them of their presence.
Play and exercise.
Using toys and balls with bells inside or squeaky toys will help build your pet’s confidence and stimulate their interest in games. Other pets in your family can also help. Placing a bell on a visual pet’s collar will allow your visually impaired or blind pet to use them as an aid. You may notice that a visual pet will recognise a blind animal’s handicap and help out by staying close to them and ‘leading the way’. Visually impaired pets can interact normally with other pets in your family. You may find though, that a once dominant pet will become subordinate once they lose full use of their vision. This is important when meeting new ‘friends’ at the park. Close supervision will be required.
Danger.
Avoid changing you pet’s environment. Keeping a stable environment will mean your pet can move freely about your home without fear of bumping into things. Once your pet has adjusted to his/her vision impairment or blindness, you will be amazed how quickly they will negotiate through the back yard and house.
Cold and windy weather decreases his/her sense of smell, and makes your pet vulnerable to strange dogs and people. Grooming, patting and talking will offer your pet reassurance.
Do not allow your pet access to swimming pools.
For more information visit - www.blinddogs.com
Pannus
Also known as Chronic Superficial Keratitis (CSK) and Superficial Stromal Keratitis (SSK). Pannus is a progressive corneal disease characterised by superficial blood vessel infiltration, scar tissue formation and pigmentation of the cornea. It occurs principally in German Shepherds and related breeds. It also occurs in Kelpies, Border Collies, Greyhounds, Siberian Huskies and a few other breeds. CSK usually starts in young to middle-aged adults. It has a slow onset, beginning in the outer margins of the cornea and later progressing to involve the inner margin of the cornea near the nose. As the disease progresses across the surface of the cornea, it appears as a pink to red or black film covering part or nearly all the surface of the eye. The edge of the film may have a white appearance. If the film progresses over the entire surface of the eye, blindness will result. The condition may be associated with a deal of discomfort. The third eyelid may also be affected in some cases.
Aetiology.
The cause of this condition is unknown, although ultraviolet light (sunlight) is suspected to be involved in the disease. As this condition is mainly seen in German Shepherd dogs, there is obviously a breed predisposition. The ultraviolet light is believed to disrupt the DNA in the cells of the surface of the eye, thus altering the cells with a subsequent reaction by the body's immune system against these altered cells.
Treatment.
Treatment of CSK is aimed at controlling the immune mediated reaction on the surface of the eye. Topical cortisone and/or immune modulating drops are administered several times a day. On rare occasions cryotherapy (freezing the surface of the eye) or radiation therapy is used. One or a combination of the above therapies plus reducing UV light exposure is usually recommended. Some owners use dog hats and dark glasses (Doggles)!
Occasionally, the condition appears to become resistant to the drops that previously appeared to work well. Don't despair - we may just have to prescribe a different type of medication to bring the condition back into line.
The earlier the condition is treated, the more rewarding the response to therapy and hence the outcome. The frequency of treatment can be reduced to easily managed levels once the condition is under control, especially during periods of low UV light eg. winter. Once the condition is under control, we normally recommend a pre- and post-summer check-up. This enables us to keep a check for increase of the disease.
Remember: Untreated SSK eventually leads to blindness. CSK can be treated and controlled but NEVER cured!
Plastic Eyelid Surgery
Entropion, Ectropion & Eyelid Openings
Entropion
Entropion is the rolling inwards of the eyelids, which often causes the eyelashes or other hair along the eyelid margin to rub against the sensitive cornea (clear window of the eye).
In most instances, entropion is an inherited condition, but can also be caused by infections or injuries to the eyelid. Old cats and deep orbited dogs are also prone to this condition. Entropion may occur in one or both eyes and may develop in one eye before it occurs in the other. It is generally permanent and often requires surgical correction. If surgery is not performed complications such as persistent discharge, conjunctivitis, corneal ulceration, corneal inflammation, corneal scarring, and dry eye (tear deficiency), may occur. This may lead to permanent blindness.
Very young puppies with entropion will often have eyelid tacking surgery performed (rather than plastic surgery), in which temporary eyelid sutures are placed. Often, these puppies do not require permanent plastic surgery once they have matured and "grown into" their facial skin. Permanent plastic surgery is usually not performed in puppies less than 5 or 6 months of age, giving the dog some time to develop its mature head conformation.
The aim of plastic eyelid surgery correction is to permanently evert or roll the affected eyelid(s) outward into a normal position. This is performed under general anaesthesia, using an operating microscope that allows for the precise positioning of the eyelids under magnification. Occasionally further surgery is necessary if the resulting eyelid fit is not perfect.
Ectropion
Ectropion is a condition of the eyelids where the eyelid margin rolls away from the corneal surface. This condition occurs most commonly in large breeds of dogs and may be concurrently associated with entropion (see handout). In most instances, ectropion is an inherited condition, but can also be caused by injuries to the eyelid.
Ectropion may occur in one or both eyes and may develop in one eye before it occurs in the other. It is generally permanent and often requires surgical correction. If surgery is not performed complications such as persistent discharge, conjunctivitis, corneal inflammation, corneal scarring, and dry eye (tear deficiency), may occur. This may lead to permanent blindness.
The aim of surgical correction is to permanently correct the position of the affected eyelid(s) into a normal position. This is performed under general anaesthesia, using an operating microscope that allows for the precise positioning of the eyelids under magnification. Occasionally further surgery is necessary if the resulting lid fit is not perfect
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Oversized Palpebral Fissure Syndrome
Dog breeds such as the Pug, Shih Tzu, Cavalier King Charles Spaniel and Pekingese; and the cat breeds such as the Persian, Chinchilla, Exotic and British short hair have shorter noses, shallow eye sockets and more prominent eyes (brachycephalic features). These dogs and cats also have unusually large, round eyelid openings. The result is oversized palpebral fissure syndrome.
The typical features of this condition include:
1. Ineffective blinking of the eyelids ("lagophthalmos"). Most brachycephalic dogs and cats blink incompletely and the center of their corneas are constantly exposed to air, causing excessive evaporation of the tear film.
2. Many brachycephalic dogs and cats sleep with their eyes open, causing serious corneal exposure.
3. Desensitization of the constantly exposed corneas of brachycephalic breeds occurs. These dogs and cats feel less of an urge to blink and may not show signs of pain when the eye is injured.
4. In brachycephalic dogs and cats, the prominent folds of skin over the nose ("nasal fold") and the hair in the nasal folds can rub on the surface of the eye ("nasal fold trichiasis"). Large nasal folds can also interfere with vision.
5. In brachycephalic dogs and cats, abnormal hair growing in the inside corners of the eyes can also irritate the corneal surface ("medial trichiasis"& “hairy caruncle”).
6. In brachycephalic dogs and cats, the skin on the inside corner of the eyes rolls in ("medial entropion"). As a result hair on the surface of the skin rubs on the cornea, causing irritation. Blindness may occur as a result of corneal scarring.
7. Brachycephalic dogs and cats are prone to globe proptosis (eyeball out of the eye socket) after trauma. Proptosis often leads to blindness and sometimes the affected eye needs to be removed.
8. Brachycephalic dogs and cats are predisposed to serious corneal ulcers, potential eye rupture and vision loss.
9. Eye trauma is more common in brachycephalic dogs and cats. In addition, dogs and cats with large eyelid openings and prominent eyes often rub their faces on the carpet or on furniture. This can damage the eyes.
10. Secondary corneal scarring often occurs in brachycephalic dogs and cats after chronic ocular irritation. In dogs this scarring can be vision threatening and may even lead to blindness.
Surgery.
Brachycephalic dogs and cats affected by oversized palpebral fissure syndrome are best treated surgically. This plastic eyelid surgery is called medial canthoplasty. During this surgery, the inside corners of the eyelids are permanently closed, effectively narrowing the eyelid openings. At the same time the abnormal hairy tissue in the inside corners of the eyes is removed. This surgery reduces corneal exposure, corrects lower eyelid entropion and trichiasis and improves pre corneal tear film stability. An added benefit of this surgery is the reduced likelihood that the eye(s) could be proptosed secondary to trauma. Medial canthoplasty surgery does not always prevent future eye problems, but it can greatly reduce the frequency and severity of problems.
Progressive Retinal Atrophy (PRA)
Progressive retinal atrophy (PRA) is a general term describing progressive retinal degenerations affecting purebred and crossbred dogs, causing progressive vision loss, ending in total blindness and eventually eye pain. Both eyes are affected.
Rods then cones are affected.
PRA is a disease of the retina, a specialised tissue located inside the back of the eye which contains cells called photoreceptors. Photoreceptors function to absorb the light focused on them by the cornea and the lens, converting light into electrical impulses that travel via the optic nerve to the brain, where vision is perceived. Photoreceptors are divided in to two groups, rods for night vision and cones for day and colour vision. PRA causes the retina to lose its function affecting the rods first, resulting in night blindness. You may notice your dog will not go out at night or stays close to you in the dark. The cones lose function later in the disease and daytime vision fails as well, leading to total blindness. The loss of vision in PRA is gradual, enabling most dogs to adapt to their handicap provided their environment does not change.
Pupils are dilated in late stages of disease.
As vision deteriorates with PRA, the pupils become dilated (larger) and the reflection from the back of the eye gets brighter, or hyperreflective. Breakdown products released from the dying retinal photoreceptors eventually cause the lenses to develop cataracts (opacity of the lens). Leaking cataracts can cause inflammation and eye pain. These cataracts can be removed to prevent chronic inflammation but as the retina is degenerating, long term prospects for vision are less favorable than cataract surgery in a dog that is not suffering from PRA. Antioxidants may slow down the progression of the disease, although there is no firm scientific evidence to prove this. Antioxidant tablets containing Vitamins A, C & E can be used. Topical anti inflammatory drops can be prescribed to make your dog’s eyes more comfortable. There is no cure for PRA.
Late or early PRA.
In some breeds PRA has been classified into an early or late form. Breeds predisposed to late PRA include the Miniature Poodle, American and English Cocker Spaniel, Tibetan Terrier, Siberian Husky and Labrador Retriever. In contrast to late PRA, early PRA is the result of abnormal or arrested development of the photoreceptors, affecting young dogs very early in life. The Collie, Irish Setter, Miniature Schnauzer and Norwegian Elkhound can exhibit early onset PRA. Generally speaking, dogs that are normal as seen with an ophthalmoscope at 7 years of age will not develop blindness from PRA. One exception to this rule may be the Australian Cattle Dog.
Some breeds of dogs that develop PRA.
The following breeds have exhibited a higher incidence of PRA and may be carriers of the recessive gene needed to perpetuate the disease. Keep in mind that PRA can be present in any breed of dog including mixed breeds.
Cairn Terrier, Miniature & Toy Poodle, Cocker Spaniel (American & English), Miniature Schnauzer, Collie (Rough & Smooth) Saluki, Dachshund (Long Haired) Samoyed, Elkhound, Tibetan Spaniel, English Springer Spaniel, Tibetan Terrier, Gordon Setter, Welsh Corgi (Cardigan), Setter (Irish & English), Akita, Labrador Retriever, Siberian Husky, Portuguese Water Dog, Rottweiler, Australian Cattle Dog and Belgian Malinois.
How is PRA inherited?
PRA is an inherited disease and the following summary can be used to determine the genetic makeup of offspring:
Both parents affected - all progeny affected
One parent affected, one parent carrier - 50% affected, 50% carriers
One parent affected, one parent free - all progeny carriers
Both parents carriers - 50% carriers, 25% affected, 25% free
One parent free, one parent carrier - 50% carriers, 50% free
Both parents free - all progeny free
DNA blood tests.
There are DNA blood tests available to determine if dogs are likely to be affected with PRA, are likely carriers for PRA or are not likely carrying the PRA gene.
This test is available for the following breeds: Briard, Cardigan Welsh Corgi, Chesapeake Bay Retriever, Nova Scotia Duck Tolling Retriever, English Cocker Spaniel, Irish Setter, Labrador Retriever, Portuguese Water Dog, Toy and Miniature Poodles, Sloughi, Old English Mastiff and Bullmastiff, Miniature Schnauzer, Siberian Husky and Samoyed. Visit: www.gtg.com.au.
Retrobulbar disease
Retrobulbar disease or orbital disease is not uncommon disease, especially in small animal patients. Retrobulbar disease means there is disease behind the eye, within the bony orbit of the skull.
The clinical signs of retrobulbar/orbital disease may include:
1. Prominent or forwardly displaced globe
2. Prolapsed third eyelid
3. Corneal ulceration
4. Pain on opening the mouth, general depression and loss of appetite
5. Blindness
6. Swelling of the periocular tissues and face
7. Excess ocular discharge
There are many possible causes of retrobulbar/orbital disease, including:
1. Tumour behind the eye
2. Infection or inflammation including abscessation
3. Salivary gland cyst or inflammation
4. Haemorrhage
5. Trauma
6. Foreign bodies
7. Ocular muscle inflammation
Although a diagnosis of orbital/retrobulbar disease is often made during consultation and definitive diagnosis of the cause of the disease can only be made after further diagnostic testing. Such tests include:
1. Ultrasound examination and biopsy
2. Head radiographs
3. CT / MRI Scan
4. Exploratory Surgery
In most cases a thorough examination of your pet’s mouth will be undertaken. Dental disease can be a common cause of orbital disease in animals.
Once a definitive diagnosis is made, the appropriate treatment plan(s) can be implemented. At this time, the prognosis or expected outcome of your pet’s eye condition will be discussed.
Sudden vision loss - SARDs
Sudden Acquired Retinal Degeneration is an uncommon condition that can affect any breed of dog. It is more common in middle aged female small breed dogs. With SARDs, there is a sudden loss of vision in both eyes. In some dogs vision loss can occur over a longer period of time e.g. days to even weeks. Some owners notice that their dogs have increased appetite and drink a lot more water around the time that their pet develops blindness.
The cause of SARDs is unknown but it may be due to a toxic or inflammatory insult to the retinal photoreceptors (light sensitive cells in the nerve tissue at the back of the eye). Diagnostic testing is often required to confirm a diagnosis of SARDs. This may include an ERG (Electroretinogram), blood tests to exclude any significant systemic disease and an MRI or CT scan of the brain.
The prognosis for SARDs is extremely poor and most dogs never regain vision. No treatment is available for SARDs. Many dogs develop secondary cataracts (opacity of the lens) when toxic cell breakdown products released from the degenerating retina interrupts normal lens metabolism. This usually occurs within 6-12 months of the onset of blindness. Cataracts can lead to lens induced inflammation within the eye. As a result the eyes can become reddened and watery. This may cause a degree of discomfort for your dog and the discomfort can be treated.
Topical anti-inflammatory medications can be used daily to reduce any discomfort and reduce ocular discharge. Chronic lens induced uveitis will often lead to secondary glaucoma (high intraocular pressure) in the eyes. Glaucoma is a painful condition and if left untreated may require surgical treatment e.g. enucleation or intrascleral prosthesis surgery.
Canine Uveitis
What is uveitis?
Uveitis is inflammation of the uveal tract, which is the blood rich layer of the eye. This includes the iris (coloured part of the eye), ciliary body and the choroid. Uveitis can involve the iris and ciliary body (anterior uveitis), the choroid (posterior uveitis) or the whole of the uvea (panuveitis)
What does uveitis look like?
Uveitis can have many clinical signs. These may include one or more of the following: squinting, sensitivity to light, third eyelid protrusion, tearing, redness in the white of the eye, abnormal pupil shape or size, an altered iris colour (usually a “muddy” or reddened colour compared to the normal colour), cloudiness, cataract, and/or enlarged eye if glaucoma is present. Blindness may be present, but often goes unnoticed, especially if the other eye is visual.
Aetiology.
Some of the more common causes of uveitis include infection, immune-mediated reactions (a complex allergic-type reaction), proteins leaking from cataracts, luxated (dislocated) lens, traumatic injuries to the eye and neoplasia (tumours). Sometimes the exact cause of uveitis cannot be identified even though the response to treatment is successful.
What is the treatment for uveitis?
The treatment depends on the cause. Anti-inflammatory medication is prescribed for topical and sometimes oral use. It is important to determine if glaucoma is present as a complication of uveitis, as this MUST be treated. If the glaucoma is not controlled, the eye will become blind and painful. It is important to understand that even with the BEST treatment, the uveitis may not be controlled and glaucoma may occur. Also, it is important to understand that uveitis in dogs is often a LIFETIME disease that requires LIFETIME treatment.
Feline Uveitis
One of the most common eye problems in cats is uveitis, and it is usually chronic and can cause blindness and ocular pain. In fact, the three most common reasons for a cat's eye to be surgically removed (enucleation) is ocular trauma (such as a severe cat claw injury to the eye), glaucoma (increased intraocular pressure) secondary to chronic uveitis, and cancer (diffuse iris melanoma). Uveitis in cats can be caused by serious or life-threatening generalized disease in the cat's body. Therefore, feline uveitis is an important disease to diagnose and treat correctly, to decrease the chances of the eye being blinded and possibly needing removal. Some diseases that present as a case of uveitis can result in death of your cat.
What is uveitis?
Uveitis is inflammation of the uveal tract, which is the pigmented, vascular part of the eye. This includes the iris (this is the colored part of the eye that forms the pupil), ciliary body, and choroid. The uveal tract (or "uvea") is all in one piece, and is shaped like a hollow ball with a large slit in it, that fits inside the eyeball. The slit is the cat's pupil, and the rest of the ball is the iris, ciliary body, and choroid which all blend together as a vascular cup. Therefore, if the iris is inflamed, it is likely that the ciliary body and choroid are involved too, either slightly or severely.
What does uveitis look like?
Uveitis can have many clinical signs. These may include one or more of the following: squinting, sensitivity to light, third eyelid protrusion, tearing, redness in the white part of the eye, abnormal pupil shape or size, an altered iris color (usually a dark muddy or reddened colour compared to the normal colour), cloudiness, cataract and/or an enlarged eye if glaucoma is present. Blindness may be apparent, but this is often not noticeable, especially if the fellow eye is visual.
What are the causes of uveitis?
In approximately 50% of cats with uveitis, the cause cannot be identified, even with extensive diagnostic tests. However, when the cause can be identified, it is usually trauma, an infectious disease, or cancer. The infectious diseases that can cause uveitis in cats are: Toxoplasma Gondii, Feline Infectious Peritonitis, Feline Immunodeficiency Virus, Feline Herpes Virus-1 and Feline Leukemia Virus. The two most common types of cancer that can cause uveitis in cats are lymphoma and diffuse iris melanoma. It is important to know that all of these diseases can be life threatening, with perhaps the exception of Feline Herpes Virus.
What is the treatment for Uveitis?
The treatment depends on the cause. Anti-inflammatory medication is usually prescribed for topical use and sometimes oral use. It is important to determine if glaucoma is present as a complication of uveitis, as this needs to be treated. If the glaucoma is not controlled, the eye will become blind and painful. It is important to understand that even with the BEST treatment the uveitis might not be controlled and glaucoma can occur. Also, it is important to know that uveitis in cats is usually a LIFETIME disease that requires LIFETIME treatment.
Viral Keratitis - FHV
Viral keratitis is most commonly seen in cats chronically infected with FHV-1. Keratitis means inflammation of the cornea (the clear window of the eye). Viral keratitis is usually seen in mature cats but can also affect young kittens.
Clinical sings of viral keratitis include:
1. Conjunctivitis
2. Branching (dendritic) or large (geographic) corneal ulcers
3. New blood vessel development in the cornea
These signs appear to occur even in the face of a recommended vaccination program and recurrences occur with suppression of the immune system (stress, feline AIDS, feline leukaemia and treatment with cortisone).
Diagnosis:
Special stains will be used during consultation to demonstrate corneal ulceration. Cultures and blood tests can be used but are not always reliable. The most reliable test is the PCR or polymerase chain reaction that tests for remnants of the genetic material or RNA of the virus.
Treatment:
Treatment varies depending on the stage of the disease and this may include specific antiviral agents, anti-inflammatory drugs, antibiotics to prevent secondary infections, and the use of the amino acid Lysine, which seems to "constipate" the virus and reduce the number and severity of the recurrences.
Complications:
Recurrences of conjunctivitis and corneal ulceration are common, especially following stressful situations. These may include boarding in a cattery, feral cats invading your cat's territory and barking dogs. Occasionally dry eye, brown pigment in the cornea (corneal sequestration), rolling in of the lower lid (entropion), white to pink growths on the cornea (eosinophilic keratitis) appear as complications.
Remember it is very common for this condition to recur and it is advisable to contact your Veterinary Eye Specialist if the condition returns.
Watery eyes & tear duct problems
Epiphora (Watery discharge)
What causes weepy eyes?
Infection, inflammation, allergy with swelling and narrowing of the tear duct openings, congenital (at birth) absence of part of the drainage apparatus (punctal atresia), narrowing of the drainage openings and blockage of the tear duct system. Some blockages are caused by the physical anatomy of the face as seen in dog breeds such as the Pekingese and in cats such as the Persian.
What do we do to manage the watery eyes?
Using the operating microscope, an attempt may be made to create a new path through which the tears can flow. Narrow openings may be enlarged or, if absent, new openings may be created. A fine nylon cannula may be inserted into the tear duct opening in the eyelid and it may pass all the way down to the nose. This may be left in place for up to three weeks. Tear drainage may be re-established once the cannula is removed. Do not allow your pet to rub the eye while the cannula is in place!