Diseases of the Eye

Here's a list of some of the more common things we find:

Ingrown eyelashes that irritate the eyeball. Common in Poodles and Cockers

Curled in eyelids (entropion) that irritate the eyes. Common in Sharpeis and Chows.

Glandular cysts and small tumors of the eyelid.

Infection or irritation of the tear glands. (Conjunctivitis or pink eye or red eye)

Dry Eye, Tear Abnormalities, and Keratitis Sicca. Also tear duct obstruction.

Prolapse of the gland of the third eyelid. (known as cherry eye...common in Cockers, Pekes, and Beagles)

Corneal ulcers and wounds and scratches

Corneal Pigmentation

Infection of the inside of the eye (Uveitis)

Cataracts and Lens displacement

Swelling of the eye (glaucoma)

Retinal diseases

Popped out eyeballs due to major trauma (especially in dogs like Boston Terriers who's eyes already bulge)

As a general practitioner, I routinely treat the simpler and more common problems listed above and refer the more difficult cases to a specialist.

Treatment and Diagnostic Considerations:

Laboratory:

A. If the surface of the eye is abnormal, we will stain the eyeball with a stain that will show any defects in the corneal surface.

B. If the eye appears dry (keratitis sicca) we will do a tear test

C. If glaucoma is suspected, we will test the pressure of the eyeball

D. Sometimes Thyroid testing is appropriate (associated with dry, crusty eyes or excessive eye matter)

E. Sometimes blood work for diabetes and a CBC (blood count) for infection is appropriate.

In cats, we often see eye inflammation in immune related diseases like leukemia, so sometimes we will test for feline leukemia and aids.

F. Parasites (hook worms and heartworms) can cause eye inflammation so sometimes we will test for these and other parasites if suspected.

G. Bacterial , Fungal, and yeast cultures are sometimes appropriate

H. Herpes testing (not contagious to people). I leave this to specialists

I. But mainly we will be using our ophthalmoscope to visually check out all the structures in the eye. For the back of the eye, we will probably need to dilate the eye with some drops and sometimes sedate the patient. Exams of the back of the eye for retinal and fundic diseases are not my strong point...I will probably refer you to a specialist if these diseases are suspected.

Treatment:

Treatment, of course, depends on the diagnosis and the severity of the problem, but here's what will be typical treatment plans:

For problems of the lids such as ingrown eyelashes, curled in lids, cherry eye, and cysts we usually pre-treat with antibiotics and anti-inflammatory eye ointments and then return in 1-2 days for minor surgical correction.

For many problems of the surface of the eye or for tear gland problems we can greatly improve or cure the problem with topical ointments.

Note: some tear gland infections (conjuctivitis) are contagious to humans (especially from rabbits and cats) so wash your hands after treating pets for conjuctivitis before you absent mindedly rub your own eyes with your fingers.

For more serious wounds of the eye we often do a minor surgery where we suture the 3rd lid over the eyeball for a couple of weeks. You might flinch when you imagine such a procedure but not only is it often successful, but it seems to be very soothing to the pet with an eye injury. Other veterinarians prefer to do the slightly more sophisticated conjunctival flap surgery which is similar.

For even more serious wounds or diseases that leave the eye not only blind but causing chronic pain or drainage, we sometimes need to remove the eye. This is a straight forward but major surgery and usually works out fine. There is, however, a fairly rare problem of the other (good) eye going blind when there is damage to the optic nerve of the bad eye. But this can happen when we don't remove the eye too.

If you want a fake eyeball put in (you can choose from some pretty exotic colors), you'll have to go to a specialist.

CATARACT PHACOEMULSIFICATION (Removal)

By Dr Pentlarge

A cataract is an opacity of the normally transparent lens. The lens is located behind the pupil and consists of clear lens fibers and epithelial cells surrounded by a capsule. The function of the lens is to bend rays of light to produce a sharp visual image on the retina.

Cataracts occur in all species of animals and are especially common in people and dogs. Heredity, diabetes mellitus, trauma, and intraocular inflammation can cause cataracts, but most cataracts in dogs are inherited or due to diabetes. Some of the popular dog breeds that have an increased incidence of inherited cataracts are the Poodle, Cocker Spaniel, Boston Terrier, Lhasa Apso, Shih Tzu, Labrador Retriever, Terrier, Golden Retriever, Bichon Frise, and Schnauzer. In some of these breeds, cataracts can develop very early in life, even before one year of age.

As an opacity of the lens, a cataract can interfere with vision depending on its location and size. When a cataract significantly impairs vision, it can be surgically removed by phacoemulsification. This is the newest breakthrough in cataract surgery in people and dogs, and is the most common surgical procedure we do. Phacoemulsification is a specialized, state-of-the-art surgery which utilizes the same equipment, surgical instruments, and medications used on people undergoing cataract surgery. Cataract phacocmulsification uses ultrasound to break (emulsify) the cataract into very small particles that are aspirated out of the eye. The lens material is carefully and completely sculpted from its capsular bag. A laser, which is a beam of light, cannot remove a cataract. The entire surgery is performed through a very small corneal incision (3.2mm) at the top of the eye with the aid of an operating microscope and specialized ophthalmic instruments. The small incision and lens phacoemulsification allows shortened surgical time, less tissue manipulation, and less tissue trauma. This provides for a more rapid physical rehabilitation and improves success. Another major advantage is that cataract phacoemulsification causes little to no pain. In fact, some dogs with cataract-induced inflammation appear to be more comfortable after surgical recovery. The cataract will not grow back. However, a thin membrane (the posterior lens capsule) that is left intact at the time of surgery may become cloudy. This does not usually appear to interfere with the dog's vision. In some patients, there are capsular opacities and capsular wrinkles even before surgery.

One or both eyes can have cataract surgery at the same time, and some patients are over 15 years of age. A complete ophthalmic and physical examination before surgery is essential. Presurgical blood and urine tests are also required. Occasional patients may also need a presurgical retinal test called an electroretinogram if there is concern about retinal function or an ocular ultrasound if there is concern about a retinal detachment. The usual stay in the hospital is 4 days, but the stay can be as short as 1 night or as long as 2 weeks. The advantage of longer hospitalizations is that we can monitor your pet extremely carefully for any postoperative complications which can significantly improve the surgical outcome. Eyedrops are needed 6 times a day for the first postoperative month. Medications are then slowly tapered to a low maintenance dose. Working owners are able to provide these treatments. Patients begin to see immediately after surgery if there are no complications. Vision continues to improve over the next 6 weeks. Postoperative examinations are scheduled approximately 1 week, 1 month, and 2 to 3 months after discharge, and then twice yearly thereafter. Follow-up evaluations are extremely important.

The success rate with phacoemulsification is very high. While it is impossible to guarantee the outcome in any particular case, at Animal Eye Care Clinic the success rate for vision is 80 to 93%. When surgery is successful, your pet's behavior will return to normal or almost normal because of the dramatic improvement in vision, especially if both eyes had cataracts. However, vision may not be perfect unless an artificial lens implant is placed. The surgical success rate is highest when the cataract is removed before it causes any intraocular damage. Presurgical inflammation and subluxated cataracts may increase the incidence of postoperative complications. The most common temporary postoperative complications are increased intraocular pressure and poor pupillary dilation. Possible blinding complications include severe intraocular inflammation or bleeding, a severe intra-ocular infection, corneal ulceration, retinal detachment, glaucoma, and intraoperative complete lens luxation. Retinal detachments and glaucoma can occur months to years after surgery. Some of these complications can result in loss of the eye. Occasionally, a small region of the iris may adhere to the lens capsule. This may alter the pupil shape, but it does not interfere with vision.

If a cataract is not removed, it can lead to inflammation, lens dislocations, glaucoma, and retinal detachment with bleeding. Many of these problems will cause your pet pain and irreversible blindness. Therefore, nonsurgical cataracts require monitoring and care.

Remember that if you elect not to do surgery on your pet's cataracts, they need to be monitored since they can lead to inflammation and infection of the eye. Another good reason for at least yearly physicals.

Lens Implants: (Cataract Replacement with a new lens)

By Dr Pentlarge

Intraocular lens (IOL) implants are used after cataract surgery to replace the removed cataractous lens. The purpose of IOL implants is to correct postoperative aphakic (without a lens) vision. In human patients, it is routine to place an IOL implant as part of their cataract surgery unless there is a contraindication. Intraocular lens implants are another new breakthrough in improving the surgical results of cataract surgery.

Patients without a lens are farsighted and may lack crisp vision. However, canine patients that do not have an IOL implant still demonstrate a dramatic improvement in their visual behavior after successful cataract surgery. This dramatic improvement is especially obvious in patients that were completely blind before surgery. However, vision will not be perfect or close to perfect without a lens implant. Yet some patients without lens implants will behaviorally act like they have normal vision or you may notice that your pet visually struggles in some situations.

The general consensus among the investigators who developed and are now using IOL implants in dogs is that the IOL implant does improve the dog's vision. This makes sense if we extrapolate from human patients. However, we cannot use human IOL implants because the dog's lens is much larger and has a much higher optical power than the human lens. Therefore, we use specially developed IOL implants for the dog that are of correct size, are of high quality, and that correct canine aphakic vision. Animal Eye Care Clinic has been placing lens implants in the majority of our cataract patients for the past several years.

The IOL is inserted into the capsular bag after removal of the entire cataractous lens by phacoemulsification-ilTigation-aspiration. The corneal incision is enlarged to 8mm for insertion of the IOL. A viscoelastic material especially designed for cataract surgery is used to protect the comeal endothelium during insertion of the IOL. Displacement of an IOL implant at some time after surgery has been reported in both human and canine patients, especially if ocular trauma occurs.

Besides improving postoperative vision, clinical evidence shows that the IOL implants may decrease the amount of opacification of the posterior lens capsule. This would further improve vision.

As investigations continue, we will learn more. In the future, we may even have injectable liquid or foldable IOL implants for the dog. Please do not hesitate to ask us any questions or to discuss with us any concerns. There is an additional fee for the intraocular lens implants. We are very excited about this new breakthrough in canine cataract surgery!

RETINAL DETACHMENT

By Dr Pentlarge

Retinal detachment means that the sensory retina has separated from the back of the eye. The retina lines the back of the inner eve and contains the light-sensitive rods and cones that change light into energy for transmitting messages to the brain. The retina is similar to the film in a camera--the image or picture is received on it.

When the retina is detached, it no longer receives its normal nutrition which results in a loss of function. Therefore, 360 degree or total retinal detachments will result in complete blindness of the affected eye. Small or partial retinal detachments usually go unrecognized by the owner because their pet will usually compensate for the impaired vision. Pets also tend to compensate well with unilateral blindness. Therefore, unless both eves are affected with a severe detachment or unless both eyes are affected with other abnormalities, retinal detachments may not be recognized in the early stages of development. In contrast, human patients can seek immediate help for any visual disturbance.

Retinal detachments occur in association with a wide variety of ophthalmic and systemic abnormalities that include congenital defects (e.g., Retinal Dysplasia), inherited defects (e.g., Collie Eye Anomaly), trauma, blastomycosis, cryptococcosis, histoplasmosis, coccidioidomycosis, toxoplasmosis, feline infectious peritonitis, trauma, systemic hypertension, hypcrmature cataracts, postop cataract surgery, postop anterior lens luxation surgery, hyperviscosity syndromes, ethylene gycol toxicosis, other toxicoses, polycythemia, immune-mediated mechanisms (e.g., Vogt-Harada Like Syndrome), and primary and secondary intra-ocular neoplasms.

A complete ophthalmic examination, including indirect ophthal moscopy, is necessary to diagnose retinal detachment. A physical examination, blood tests, serology, blood pressure measurement, and other tests may also be necessary.

The degenerative changes within the detached retina occur quickly in the cat and less quickly in the dog. The cause of the detachment, the type of detachment, the severity and location of the detachment, and the duration of the detachment will affect the prognosis. Many retinal detachments are not treatable.

Some types of retinal detachment (e.g., detachments due to systemic hypertension and immune mechanisms) are managed by medical and diet therapy.

Unfortunately, the majority of veterinary eye specialists have limited exposure and experience with retinal detachment injuries. In selected patients, we are performing Nitrous Oxide retinal cryopexy and Diode Laser photocoagulation rectinopexy.

These procedures are also used in human patients. Retinal cryopexy uses extreme cold and laser surgery uses light energy to try and scar the detached retina back into place or to try and prevent progression of the detachment. These proccdures try to form adhesions between the sensory retina and the back of the eye. In selected patients, retinopexy may be recommended prophylactically if the eye is at high risk of future retinal detachment (e.g., hypermature cataracts, lens dislocations). Other retinal detachment surgeries include scleral buckling procedures and pneumatic retinopexy.

For some types of retinal detachments, a combination of surgeries is performed. Unfortunately, retinal detachment surgery is not always successful. Chronic retinal detachments can lead to intraocular bleeding and may increase the risk for developing glaucoma. Otherwise, a retinal detachment is not painful.

A Few Extra Comments from Dr Ross about Retinal Degeneration

Retinal degeneration that is not linked to high blood pressure (hypertension) is uncommon in the cat. In Abyssinian and Siamese cats a progressive retinal degeneration (PRA) has been described in young cats.

Taurine is an essential aminoacid to the cat, this means that cats fed diets deficient of Taurine (eg. vegetarian diets, or dog diets) are at risk of developing Central Progressive Retinal Atrophy (CPRA). Cow's milk is deficient in taurine, so use a commercial cat milk replacer if you're hand rearing kittens.

EYELASH DISORDERS

By Dr Pentlarge

Eyelash disorders are very common in the dog and less common in other species. When abnormally positioned hairs contact the surface of the eve, they can cause pain and injury. Severe irritation can even lead to corneal ulceration and scarring. Signs of eyelash disorders include excessive tearing, squinting, Conjunctival redness, abnormal ocular discharge, pawing at the eve, and depression.

Distmichiasms is an abnormal condition in which extra eyelashes appear along the margin of the eyelid(s) where ordinarily they should not grow. Distichiasis can occur in any breed, but there is a predisposition in the Cocker Spaniel, English Bulldog, Shih Tzu, Boston Terrier, Lhasa Apso, Golden Retriever, and Sheltic. This condition max' be inherited.

In trichiasis, hairs growing from a normal location come in contact with the surface of the eye. Trichiasis occurs when normal hairs turn inward, when an eyelid margin is turned inward(e.g., lower medial entropion), or when hairs on a facial fold touch the eye. Trichiasis from facial folds and heavy brows occurs in breeds with very shortened noses (brachycephalics).

Ectopic cilia are abnormal hairs that are growing from the underside (conjunctival side) of the eyelid. These hairs usually cause severe pain and frequently lead to corneal ulceration. Ectopic cilia are more difficult to identify, requiring careful examination with magnification and a bright light source.

Various procedures are used to correct the different eyelash disorders. Nasal fold trichiasis requires surgical removal of the nasal fold. Lower medial entropion with secondary trichiasis is treated with surgical eversion (rolling outward) of the inner lower eyelid or by cryosurgery. In dogs with abnormally large eyelid openings, medial entropion with trichiasis may be corrected by surgical excision of the hairs with permanent partial inner eyelid closure.

Ectopic cilia are treated by cryosurgery and/or surgical excision. Cryosurgery uses extreme cold to destroy the roots of hairs, permanently removing at least 80% of treated hairs. Cryosurgery is the treatment of choice for distichia and some forms of trichiasis. It is more successful and causes less scarring than electrolysis.

Cryosurgical treatment of eyelash disorders requires general anesthesia. Patients are then positioned under an operating microscope which provides magnification and a bright light source.

Goals of Management and Care

1. Swelling, redness, and mucoid to blood-tinged discharge are normal for the first 7 to 14 days alter surgery. The amount of swelling ranges from mild to marked.

2. Keep the eye clean of discharges. Discharges trap bacteria and inactivate medications. We recommend you use Bausch & Lomb Sensitive Eves Saline Solution and white tissues to clean the eve.

3. Some coughing for the first postoperative week is normal as the airway mar be sore from the tracheal tube used for inhalation anesthesia. If coughing is severe, please call us.

4. Cryosurgery will cause a loss of pigment along the eyelid borders and occasional mild sloughing of conjunctival tissue in the treated areas. In almost all patients the pigment slowly returns over the next 6 months. However, a pink "freckle' may persist.

5. Regrowth of some hairs after cryosurgery is possible. Regrown hairs are usually softer, but if these hairs cause irritation, then the surgerv should be repeated. Fortunately, the need for a second surgery for distichiasis has been uncommon.

Canine Dysautonomia

Dysautonomia (DIS-auto-NO-mia) is a condition characterized by a malfunctioning autonomic nervous system-the system responsible for involuntary functions like the contraction of smooth muscles, the heart rate, regulation of the pupil size, and so on.

Dogs suffering from the disease typically have dilated pupils that don't respond to light, decreased tear production, and elevated third eyelids. They may also suffer from vomiting or regurgitation due to decreased motility in the digestive tract.

In the majority of cases, the disease is incurable and fatal.

Dysautonomia was first documented in horses in the United Kingdom in the early 1900s. "Grass sickness," as the equine version is known, is still a problem.

In 1982, researchers at the University of Bristol first diagnosed dysautonomia in a cat. What at first appeared to be an anomaly soon became an epidemic, with several hundred cats being diagnosed with feline dysautonomia across the United Kingdom and Europe.

Cases of canine dysautonomia have been diagnosed throughout Europe and in the United States. In most areas, it's a sporadic occurrence. But for reasons that remain unclear, the highest incidence has been in Kansas and Missouri.

Missouri's first dysautonomia case was diagnosed in a cat in 1986, and only a handful of other feline cases have been documented.

The cause is unknown, and no one is sure why the incidence is so much higher in Kansas and Missouri.

What researchers do know is that there are some common threads in the histories of dogs afflicted with the disease.

The study confirmed suspicions that rural dogs tend to have a greater incidence of the disease. When those afflicted with dysautonomia were compared to rural control dogs, the affected dogs were more likely to have access to pasture land, farm ponds, and cattle, and to have consumed wildlife.

Dogs with dysautonomia were also generally young, according to the study-the median age was about 18 months. The disease occurred most frequently from February to April, with only a few cases identified during the summer or early fall.

The dogs who appear to be at high risk are mostly free-roaming dogs out in the country.