Glendale Animal Hospital - The Family Veterinarian

DISEASES OF THE EYE

DISEASES OF THE EYE LIDS

BLEPHARITIS

Blepharitis is inflammation and often infection of the eyelids and may involve one or both eyes. Bacteria, fungi, parasites, allergies and trauma may all cause this condition. White or light-colored cats exposed to extremes in sunlight can have what is known as a Solar Blepharitis and become predisposed to having squamous cell carcinoma. Most cats show signs of swollen and thickened eyelids, loss of hair on the lids and redness around the area. In advanced cases, crusting and exudates may be present and conjunctivitis or keratitis will occur. Diagnosis is based on history, physical exam, skin scraping, cytology and cultures of exudates. ((Blepharitis))

TREATMENT OF BLEPHARITIS

Treatment of blepharitis centers on elimination of the primary cause. Bacterial infections are often Staphylococcus infections, so strong oral antibiotics are needed. Topical drops are used if conjunctival or corneal irritation is occurring. Prednisolone or triamcinolone are often used in cases of allergic blepharitis and may be used short term to relieve swelling of the lids. Parasitic diseases are treated based on the parasite present while fungal infections are treated with antifungal drugs and topical creams. Chronic cases can possibly be treated using what is called a "staph lysate", a product designed to stimulate the body to better fight off the usual type of infection.

 

 

TRICHIASIS/DISTICHIASIS

Trichiasis occurs when eyelashes or other normally placed hairs curl towards the surface of the eye and cause irritation of the corneal surfaces. Distichiasis occurs when eyelashes grow abnormally from a gland in the eyelids called the tarsal gland. This allows the lashes to grow directly towards the surface of the cornea.

Trichiasis occurs most often in cats with eyelid agenesis, in Persian cats with prominent nasal folds (skin which rubs near or on the eye) and when cats have entropion. Distichiasis occurs uncommonly. It is considered a genetic problem or defect. ((Trichiasis/Distichiasis))

The clinical signs of these conditions are chronic irritation to the eye surface. Pain is present, an increase in tearing occurs and the cornea may become cloudy or blackened if the irritation is severe enough or goes on long enough, keratitis or corneal ulceration are possible. Diagnosis is based on the symptoms and physical examination.

TREATMENT OF TRICHIASIS AND DISTICHIASIS

For simple cases of trichiasis, epilation of the hairs, preferably using electrolysis, works well but will not guarantee that the hair will not regrow. Cryoepilation, freezing the follicles, works well and may be more permanent. For distichiasis, your veterinarian may surgically remove part of the eyelid that contains the misplaced follicles; a procedure called eyelid splitting. Here too, lashes may still regrow. Cats with agenesis of the eyelids, prominent nasal folds and entropion need to have these conditions treated specifically.

 

 

PROMINENT NASAL FOLDS

Cats with very short noses, especially the Persian breeds, can have large folds of skin between the nose and eyes called nasal folds. The skin and hair will rub against the surface of the eyes causing tearing and, in prolonged cases, keratitis and corneal ulceration. Diagnosis is based on history and physical examination.

TREATMENT OF PROMINENT NASAL FOLDS

No treatment is needed unless irritation and damage to the eyes is occurring. In these cases, irritation and corneal changes can be treated with antibiotic and steroid drops (unless ulcers are present); surgical removal of the nasal fold will generally solve the problem.

 

 

ENTROPION

Entropion is when the eyelids and therefore, the eyelashes are turned in towards the cornea. The condition is sometimes inherited, most often in Persian-type cats, but more commonly occurs after catfight wounds heal. Clinical signs will depend upon how severe the entropion, or how many lashes are contacting the corneal surface. Tearing, pain, exposure of the third eyelid (a pain response) and keeping the eye more closed will all be present. In advanced cases, conjunctivitis and keratitis will occur. If allowed to persist, permanent damage to the cornea will lead to blindness due to corneal pigmentation and corneal ulceration may appear. Diagnosis is based on physical examination.

TREATMENT FOR ENTROPION

Surgical correction amounts to removing some portion of excess skin and suturing the margins leading to lid reposition. A type of plastic surgery, many different techniques exist and are beyond the scope of this program. The technique chosen should best suit the entropion present, but the experience of the surgeon is most important in producing the most functional and cosmetic results.

 

 

DISEASES OF THE THIRD EYELID

PROTRUSION OF THE THIRD EYELID

Sometimes, the third eyelid may appear to have slid out and covered part of the eye; usually this occurs in both eyes. The cause of the condition is not understood but thought to be caused by a unique virus. Many cats will have diarrhea or very watery feces but no other ocular abnormalities when this condition is present. Some times the third eyelid may protrude when the cat has lost weight, is dehydrated, has ocular pain, a small eyeball or has neurological diseases affecting the muscles around the eye. This condition also occurs when animals are sedated or on certain tranquilizers. If there is an underlying cause it should be sought and corrected, as otherwise there may not be a specific treatment. ((Protrusion of the Third Eyelids))

 

 

PROLAPSE OF THE GLAND OF THE THIRD EYELID (CHERRY EYE)

Inside the third eyelid is a paper-thin gland that contributes to the tear film. This gland may come inside-out and swell greatly causing the clinical sign known as a "cherry eye". This is considered to be a genetic defect as the greatest percentage of cats presenting with this problem are Burmese; otherwise the condition is quite rare. This may occur for no apparent reason, after mild trauma, or when conjunctival infections occur. Diagnosis is obvious.

TREATMENT OF PROLAPSE OF THE GLAND OF THE THIRD EYELID

If left untreated, the cat may have recurrent conjunctivitis and corneal damage. Removal of the prolapsed gland, which is a relatively simple procedure, is the most common method of treatment. This treatment, however, may predispose some cats to keratoconjunctivitis sicca, which is a serious and chronic condition, so caution and consideration should be exercised.

Other techniques are to reposition the gland into a "pocket" made by the surgeon, or to push the gland back into place, holding it there with sutures. While these procedures may be more involved and costly, long term usefulness of the gland and the lessened chance of compilations may be well worthwhile.

 

 

DISEASES OF THE CONJUNCTIVA

CONJUNCTIVITIS

Conjunctivitis, the inflammation of the conjunctival membranes of the eye, is common in cats. This may involve one or both eyes and be acute or chronic in nature. Clinical signs include the eye(s) appearing red and injected, there may be swelling to the conjunctiva and a discharge ranging from clear and thin to thick and green/yellow will be present. The eyes may be painful with the cat keeping the eye partially closed and exudates may form crusts around the eyelids.

There are many causes of conjunctivitis including dust, pollen, infections and allergies. Infectious causes include pneumonitis, herpesvirus, calicivirus, mycoplasma and staphylococcus bacteria. Some of these cases will also present with concurrent upper respiratory infection. Conjunctivitis may occur secondary to trichiasis, tumors, "cherry eye", entropion and loss of tear production in cases of keratoconjunctivitis sicca. Foreign objects such as foxtails may lodge in the eye and cause irritation. Outwardly, many cases appear similar no matter what the cause. Diagnosis is based on the history and physical exam of the eye, cultures, conjunctival cytology and schirmer tear testing to measure tear production. 

NEONATAL CONJUNCTIVITIS

In very young kittens it is possible to have infections occur before the eyelids have opened. This usually results in pus formation, corneal ulceration, pigmentary keratitis, blindness and phthisis bulbi. The causes for this condition usually include pneumonitis, herpesvirus, calicivirus, mycoplasma and staphylococcus bacteria.

FOLLICULAR CONJUNCTIVITIS can occur when lymph follicles located in the conjunctiva become stimulated and enlarged. Sometimes the follicles may persist even after the initiating cause has been removed and cured. Follicles also exist on the third eyelid and these too may become grossly enlarged. This is known as folliculitis of the third eyelid. Usually, folliculitis will occur after prolonged stimulation, as in a prolonged infection, although allergic reactions can quickly stimulate the follicles to enlarge.

Clinical signs include those of conjunctivitis, plus a rough, cobble-stone appearance to the conjunctiva and/or third eyelid, a thick mucoid discharge and the membranes may appear more reddened than in simple cases of conjunctivitis. Diagnosis is based on these clinical signs, cultures and cytology of conjunctival scrapings.

TREATMENT OF CONJUNCTIVITIS

Determination of the cause of the disease is most important, with consideration for the duration and severity secondary. Cleaning the eye and applying antibiotic and/or steroidal drops or ointments is common; many combinations are available. Oral antibiotics such as amoxicillin, sulfa drugs, enrofloxacin or Clavamox are all used. Prednisolone or triamcinolone is used to control inflammation and treat allergic disease. Cats with suspected viral infections might benefit from the use of oral and topical antiviral medications now available. Most cases of follicular conjunctivitis are treated in a similar fashion but may take longer to enact a cure. Kittens with neonatal conjunctivitis will need to have the eyelids manually separated and the infection cleaned away before medications will work. Some kittens may have damage so severe as to make removal of the eye the only option.

 

 

KERATOCONJUNCTIVITIS SICCA (DRY EYE, KCS)

Also known as KCS, dry eye is a chronic eye disease resulting from a decrease or loss in tear production in the eye. While the cause in most cases will be unknown, immune mediated disease, neurologic conditions, trauma, infections, drugs, toxins and other systemic diseases have all been implicated. The problem is uncommon and usually less severe than it appears in the dog.

Clinical signs of the problem will include a thick mucus discharge, pain, conjunctivitis and corneal changes due to keratitis, including whitening or black scaring of the cornea. In some cats, the eye may appear grossly dry, but this alone is not diagnostic, as some infections will inhibit tear production. Diagnosis is based on the history, clinical signs and performing a schirmer tear test. Cats producing less than 5mm tears in 1 minute of testing have KCS. Cats producing over 10mm of tears in the same time are generally normal.

TREATMENT OF KERATOCONJUNCTIVITIS SICCA

While a few cats will recover completely from KCS, most will need lifetime therapy. Solutions to moisten the eye, stimulate natural tear production and control infection are all-important considerations. Your veterinarian may use artificial tears, a special KCS solution that will be customized for your cat, or cyclosporine drops/ointment. It is also possible to transplant a salivary duct into the eye, the saliva then acting as tears. This surgery will usually need to be done by a specialist and can be complicated by excess tearing or mineral plaques forming on the cornea.

 

 

DISEASES OF THE TEAR DUCTS

DACRYOCYSTITIS

Dacryocystitis is inflammation (and often infection) of the tear ducts and tear sac of the eye. Clinical signs include a thick, yellow/green discharge with signs of mild conjunctivitis and increased tear production. Outwardly, this may be confused with KCS; tear production, however, will be normal. Cats with severe conjunctivitis will also present in a similar fashion. Diagnosis is based on clinical signs, a normal tear test, cultures, cytology and flushing of the tear sac and ducts under anesthesia.

TREATMENT OF DACRYOCYSTITIS

Treatment and diagnosis may go hand in hand. As flushing of the sacs and ducts will prove the diagnosis in suspected cases, flushing of the ducts with saline and antiseptic solutions is the first step in treatment. Topical antibiotic/steroidal drops and oral medications are also needed. In some cases, usually those where damage has occurred to the ducts, surgery to reopen them is needed. This will involve passing a catheter through the ducts from the eye into the opening in the nose, leaving that catheter in place for 2 weeks or more.

 

 

EPIPHORA (INCREASED TEARS)

An increase in tear production by itself is not a disease, but most often a symptom. Some cats may be born with or acquire, due to disease, a blockage in their tear ducts. This causes normal tear production to flow over the corner of the eye. In some cats, the tears will turn a brown-red color as enzymes in the tears oxidize. Most cases are caused by a poor outflow of tears occurring after a cat has had herpesvirus infections, due to bulging eyes as the Persian breeds are prone to have, from having no opening to the tear ducts, which is a genetic defect and after dacryocystitis has occurred.

Foreign objects and hair in the eyes, dust and allergies can otherwise cause an increase in tear production. There are also rare cases where an eye increases its tear production. Elimination of the primary cause will generally solve the problem except in cases where tear ducts are damaged or closed. Surgery or flushing of the ducts may be needed and can be useful to re-establish tear flow.

 

 

DISEASES OF THE CORNEA

KERATITIS

Keratitis is inflammation of the cornea, the clear layer at the very front of the eyeball. There are several various presentations ranging from very superficial to deep and ulcerated. When the cornea is being damaged, certain signs will occur: a loss of transparency, usually causing the cornea to whiten or look cloudy; pigmentation which is like scar tissue will appear white or black; vascularization, seen as tiny blood vessels migrating into the cornea; circumcorneal injection which is inflammation and blood vessels appearing where the cornea (clear) meets the sclera (white); pain as noted by the eye being partially shut; and increased tear production.

Diagnosis of keratitis is based on clinical signs, ophthalmic exam, cytology, cultures and pressure tests of the eye. Many times corneal disease is an extension of some other process or secondary to infections and mechanical irritants, so identification and elimination of these is very important. With this information in mind, the sub-classifications of Keratitis can be explored:

PIGMENTARY KERATITIS

Pigmentation of the cornea is common after prolonged irritation. It is seen most often in cats with bulging eyes like the Persian, but generally is uncommon. External irritants, KCS, trichiasis/distichiasis, entropion, corneal injuries and chronic infections of the eye may all produce this result. Diagnosis is by direct exam, cultures, fluorescein staining, Schirmer tear testing and cytology.

SUPERFICIAL KERATITIS

While the causes of superficial keratitis may be uncertain, immune mediated disease, herpesvirus, abnormal tear production and extension of generalized conjunctivitis and damage from all the previously mentioned irritants can all lead to this problem. Clinical signs will vary greatly and depend on initiating causes. These include the following: a loss of transparency, usually causing the cornea to whiten or look cloudy; pigmentation, vascularization, seen as tiny blood vessels migrating onto and into the cornea; circumcorneal injection which is inflammation and blood vessels appearing where the cornea (clear) meets the sclera (white); and pain as noted by the eye being partially shut and increased tears being formed.

DEEP KERATITIS (INTERSTITIAL KERATITIS)

Deeper, more extensive cases of keratitis often are extensions of superficial infection, systemic disease, corneal injuries and secondary to anterior uveitis, herpesvirus infection and glaucoma. Most cases will exhibit heavy loss of transparency, heavy vascularization of the cornea, changes to the iris and possibly the collection of material behind the cornea in the anterior chamber. Diagnosis is based on the history and these clinical signs. Scar tissue formation on the cornea may occur if the initiating cause is not treated and cured.

EOSINOPHILIC KERATITIS

Eosinophilic keratitis is unique to the cat. A white-to-pink, raised area will grow upon the cornea and conjunctival tissues. They usually start where the cornea (clear) and the sclera (white) meet, growing and progressing towards the center of the cornea over time. Left untreated, the entire corneal surface can become involved. Although one eye is usually involved initially, both usually become involved in time. The eye rarely has much discharge and most cats are without pain. Diagnosis is based on the history, clinical signs and cytology of the corneal tissues.

TREATMENT OF KERATITIS

PIGMENTARY KERATITIS

Removal of the cause of the keratitis and direct treatment of any infection present is most important. The use of topical steroids should bring dissolution of superficial pigments within 30-45 days. Deeper, more advanced cases can have permanent pigmentation that may be controllable with topical medication, but more often, may necessitate radiation or surgical treatment, including corneal transplantation to restore vision.

SUPERFICIAL KERATITIS

Depending on the actual cause, if it can be determined, there are various medications used to treat this condition. As before, removal of the initial cause is most important. Topical antibiotic and steroidal drops or ointments are often used. Oral antibiotics and steroids may also be needed. Cyclosporine and atropine drops are used in more severe cases.

DEEP KERATITIS

Also called interstitial keratitis because the inflammation runs throughout most of the cornea, deep keratitis causes more marked changes in the cornea. Again, removal of the initial cause is most important. Topical antibiotic and steroidal drops or ointments are often used. Oral antibiotics and steroids may also be needed. Atropine drops should be used to reduce pain and dilate the pupil. Treatment may be needed for several weeks.

EOSINOPHILIC KERATITIS

Early cases may respond to topical cortisone-type medications alone but is generally advised that topical and oral cortisone is used for weeks. Some doctors prefer to inject the conjunctiva with long lasting steroids. If these treatments fail, oral megestrol acetate is often effective but there can be many harmful side effects from this medication if not carefully used. Some animals can stop therapy after a time; others will need regular or repeated care to prevent recurrence.

 

 

CORNEAL SEQUESTRATION

A condition unique to the cat, this disease produces a brown-black spot in the center of the cornea with small blood vessels seen growing onto the corneal surface. Most cats can be affected but Himalayan, Burmese and Persian breeds are most often seen. Besides the obvious lesion, clinical signs include increased tears, redness to the conjunctiva, holding the eye closed and sometimes swelling of the conjunctiva. The cause of the condition is unknown or poorly understood.

TREATMENT OF CORNEAL SEQUESTRATION

Removal of the lesion surgically and grafting of some conjunctival tissue will relieve pain and aid in corneal healing. With time and supportive medications most cats can regain relatively good vision in the eye.

 

 

CORNEAL ULCERATION

Ulceration of the cornea involves a loss of integrity to the corneal surface and a hole forming therein. Ulcers can occur directly from trauma such as cat scratches or puncture wounds, or secondary to infections, chemicals, chronic irritation and other systemic diseases.

Ulcers are extremely painful, with most cats keeping the eye partially or completely shut. Eyes will tear excessively and the discharge may turn thick and greenish. Signs of conjunctivitis are often present, with the usual signs of keratitis, plus the obvious variation in the contour of the corneal surface. The ulcer, however, in mild cases may be small and go unnoticed by the cat owner. ((Corneal Ulcer))

Diagnosis is based on history and physical examination and your veterinarian performing a fluorescein dye test that will easily pinpoint and evaluate any ulcer present by using a wood's light. (blacklight) Cultures and corneal cytology should also be performed to help direct the best possible treatment.

TREATMENT OF CORNEAL ULCERATION

Corneal ulcers can range from very small and punctate to large and erosive, even eroding clear through the cornea and causing the eye to rupture! Treatment, therefore, will always depend on the depth and severity of the ulcer(s). After removal of any initiating cause (in all cases), small, superficial ulcers often can be treated with topical medicated ointment (depending on cause), atropine to help relieve pain as needed and oral medications for infection as indicated by culture.

As a general principle, topical steroids should be avoided in all cases of corneal ulceration, as they are prone to quickly expand the problem and inhibit healing. Mild or moderately severe ulcers will be treated using a custom ulcer mixture most vets can prepare in their offices. This "Ulcer Mix" is a combination of drugs used to combat infection, relieve pain and assist healing of the cornea.

With larger, deeper ulcers, protection and support of the cornea is very important to assist healing. The use of a third eyelid flap with or without the eyelids being temporarily closed is most commonly employed. The ulcer would be cleaned and the third eyelid sutured temporarily over the eye, acting like a live a patch that nicely supports the healing process. Very deep ulcers may require that the cornea itself is sutured first, then the flap procedure performed. Other treatments include conjunctival flaps, corneal grafts or special contact lenses. ((Eye Flap Procedure))

 

DISEASES OF THE SCLERA

EPISCLERITIS (DIFFUSE EPISCLERITIS)

The sclera is the white part of the eye that comprises most of the eyeball itself. Episcleritis occurs when this tissue becomes generally inflamed, most commonly due to a hypersensitivity reaction. This may occur in along with cases of conjunctivitis or keratitis.

Clinical signs include redness to the sclera including an increase in the number and size of blood vessels apparent on the surface of the globe. The cornea may become cloudy in the area where the cornea and sclera meet and later the entire cornea may become cloudy and have small blood vessels growing on the surface thereof. Usually there is no discharge unless secondary conjunctivitis also occurs. Cases usually start slowly and get worse with time. Diagnosis is based on the clinical signs and blood testing.

TREATMENT OF EPISCLERITIS

Most cats do well if the condition is caught early by giving topical steroid drops or cyclosporine. More advanced cases will also need oral cortisone or azothioprine. Some cats will benefit from injections given directly into the conjunctiva near the eyeball. While this sounds unpleasant it can be a very effective treatment. Long-standing cases may be somewhat difficult to treat.

 

 

SCLERAL ECTASIA

Scleral ectasia defines an abnormal development of the sclera, specifically the white connective tissue forming the globe. It is quite uncommon in cats, most commonly seen in the Siamese breed. The outward appearance of this condition may not be readily apparent and may cause no problems with eye function, but rather, seen on ophthalmologic examination of the eye. Diagnosis is based on ophthalmologic examination.

 

 

DISEASES OF THE ANTERIOR UVEA

ANTERIOR UVEITIS

The uvea is part of the inner eye lining which includes the iris which is the colored part of the eye responsible for opening and closing in response to how much light is present, the ciliary body which helps hold the lens in place and the choroid which lies just under the retina. Anterior Uveitis, then, is inflammation of the iris and ciliary body.

Causes of anterior uveitis most often include toxoplasmosis, FIP and FeLV. Trauma, other infections, systemic disease and immune mediated disease including allergic reactions and autoimmune processes can otherwise lead to uveitis. The underlying cause should always be sought. Clinical signs include reluctance to look at or be in the light, keeping the eyes more closed and increased tearing. Advanced cases will show signs of keratitis, blood and/or pus will collect behind the cornea in the anterior chamber and the iris will become rough, thickened and irregular, with the pupil being small.

You veterinarian will diagnose this problem based on history and ophthalmic exam, ocular pressure measurement and often blood testing including serology to investigate the possibility of systemic diseases. This disease may be confused with corneal diseases, outward infections or glaucoma.

TREATMENT OF ANTERIOR UVEITIS

Diagnosis and treatment of any primary or systemic disease is of the utmost importance. Treatment of the uveitis without cure of internal illness will invariably yield poor results. General therapy must include the use of oral steroidal and nonsteroidal anti-inflammatory medications and topical atropine. Many veterinarians will also employ oral antibiotics but these are considered to be of lesser importance in the treatment of this disease.

 

 

DISEASES OF THE LENS

CATARACTS

A cataract implies a partial or complete loss of transparency to the lens due to opacity. Some cataracts are heritable and can develop spontaneously early in life. Some develop secondary to aging, other ocular diseases, diabetes mellitus, drugs, chemicals, trauma and poor nutrition. The clinical signs are obvious upon physical examination. Cataracts are quite rare in the cat, even in cats with diabetes. ((Cataract))

Diagnosis is based on direct examination of the eye and identification of the opacity of the lens. As cataracts develop at grossly varied rates, it is hard for most veterinarians to determine if small cataracts will become complete and if so, how fast. Cats with rapidly developing cataracts should have blood screening. Owners mistake often loss of corneal transparency for a cataract, but to be clear, cataracts occur in the lens which is behind the pupil/iris.

TREATMENT OF CATARACTS

Cataracts can only be treated by surgical removal. Some veterinary ophthalmologists will also place an artificial lens after such a surgery, but most cats have relatively good vision after removal of the cataract. There is not other valuable treatment currently proven.

 

 

DISPLACEMENT OF THE LENS (LENS LUXATION)

On occasion, the lens may become detached from the internal attachments and move forward or backwards to varying degrees. The condition is most common in Siamese cats. Diagnosis is made by direct examination and is straightforward as long as the cornea is clear. Lens displacement can occur after trauma, spontaneously in some cats, or secondarily in cases of glaucoma, cataracts, anterior uveitis and where tumors of the eye are present. Treatment is to remove the displaced lens. ((Lens Luxation and Glaucoma))

 

DISEASES OF INTERNAL EYE STRUCTURES/EYE AS A WHOLE

GLAUCOMA

Glaucoma is an increase in the internal pressure in the eye, usually due to decreased outflow of the fluids produced within the eye. This failure is most often secondary to anterior uveitis, lens displacement, trauma and tumors of the eye. Cases may present acutely or be ongoing and chronic in nature, depending on the cause. In general, the signs of this condition are slowly progressive.

Clinical signs include dilation of the pupil, redness to the eye, a cloudy cornea, pain as evidenced by the cat keeping the eye more closed, tearing, exposure of the third eyelid and enlargement of the eye followed by blindness in later cases. Pain may also lessen as the disease progresses. Diagnosis is based on history, clinical signs and examination, including measurement of intraocular pressure. ((Lens Luxation and Glaucoma))

 

TREATMENT OF GLAUCOMA

Acute glaucoma is considered a medical emergency and should be treated as quickly as possible. The use of steroids and intravenous mannitol to reduce intraocular pressure is important, followed by the use of drugs such as methazolamide, acetazolamide and pilocarpine to reduce the inflow of and increase the outflow of ocular fluid. Special procedures such as the use of liquid nitrogen freezing or laser surgery can be employed by specialists to correct the basic functional defects within the eye. Early aggressive treatment is a must if vision is to be preserved.

In cases of chronic glaucoma where vision is poor or has been lost, treatment may be useful to prevent further expansion of the eye and minimize pain. Many authors advise enucleation of the eye to permanently relieve pain and the suffering of the cat. Drugs and other specialty surgical procedures have also been used to stabilize glaucomatous eyes but the cost and variable results make most procedures less desirable than enucleation.

 

 

BLINDNESS

While some cats may be born blind, blindness secondary to other problems is seen far more commonly. Diseases causing corneal opacity such as keratitis and anterior uveitis, cataracts and glaucoma all cause blindness. Congenital and/or genetic defects of the eye, neurologic diseases, traumatic injury of the eye and head trauma are other possible causes.

It is the retina, the lining in the back of the eye that is the final light receptor. The retina transmits the image to the brain via the optic nerve where it is interpreted by the brain. Congenital defects of the retina, abnormal retinal development, inflammatory diseases which involve the retina, retinal degeneration (atrophy) and retinal detachment secondary to trauma will all lead to blindness in the cat. Neurologic diseases that alter brain function, such as stroke, will also lead to blindness although, in these cases, the eyes would appear perfect and functional. Besides blindness, other clinical signs may not be exist unless there is systemic or some other primary disease is present.

These complex and variable conditions are beyond the scope of this program, but fortunately are relatively rare. In the cat, retinal degeneration due to nutritional imbalances including taurine deficiency has been well documented. Most quality cat foods are now supplemented to prevent this condition. Diagnosis by your primary care veterinarian with assistance from an eye specialist is the best way to deal with these problems. Cats with permanent blindness often do very well as long as kept in a stable and confined environment. Their other senses are far more important and sensitive, so loss of vision is not as devastating to cats, as it would be in people.

 

 

PROLAPSE OF THE EYE

Also known as proptosis of the globe, a prolapse of the eye occurs when the eye moves out of the socket. It is more common in Persian-type breeds. Most often head trauma,

dog attacks, catfights and cats hit by cars are responsible for this type of injury. It is considered an ocular emergency and immediate medical attention should be sought.

TREATMENT OF PROLAPSE OF THE EYE

The eye should be cleaned and free from debris. If the eyeball has not ruptured, it should be replaced. Under anesthesia, your veterinarian will clean and lubricate the globe and then manipulate it carefully into the socket. The eyelid will be sutured closed to hold the eye in place during the healing period and some veterinarians will try a wrap over the head and eye. Antibiotics orally will be used to prevent infection. Some cats will not retain their vision, but the eye will outwardly appear normal and be cosmetic. If the eyeball ruptures, your doctor will need to remove the entire eye.

 

 

MICROPHTHALMOS AND PHTHISIS BULBI (SMALL EYE)

Small eyes, called microphthalmos, are rare but can be congenital in young kittens. Phthisis bulbi occurs as a complication to trauma, infections or glaucoma where the damaged eye then scars and shrinks. This is generally not painful but there is no treatment for either condition. Enucleation may be needed in some cases if complications do occur.