I have compiled a listing of some of the eye problems the are dogs, some of their symptoms and causes as well as the most common treatments. I would like to point out that this is not intended to be a self-help guide to treating eye problems. Any eye abnormality, no matter how minor looking, is cause for a visit to the vet. I would is hoped that this information will supplement your understanding of the various conditions that affect the eyes of your dogs.
- Cataracts
Definition: Cataracts are opacities in the lens of the eye. Many people mistakenly think the cloudiness is on the surface (thought to be a "film" on the eye), but in fact, the cloudy lens is deep inside your pet's eyeball.
Why Did Your Pet Get Cataracts?
Most cataracts are inherited, and are found in many breeds such as the Cocker Spaniel, Poodle, Husky, Schnauzer, Golden and Labrador Retrievers, and terriers. Other causes of cataracts include: Diabetes, trauma, inflammation, and puppy milk replacers. Many cataracts will worsen to the point of blindness but certain types, especially in the Retriever breeds, can remain small for the entire life of the patient. A common phenomenon occurs in many developing cataracts where the patient can develop an allergic type of reaction to the cataract. This allergic reaction is a LOCAL reaction and can result in many complications such as scar formation and glaucoma.
Treatment: The surgery is performed under general anesthesia and depending on the specifics of the cataracts, age, and cause the ophthalmologist may perform either a small incision technique (phacoemulsification) or a large incision method (extracapsular cataract extraction). The small incision technique is more common today and carries the benefits of shorter surgery and healing times. Often, the ophthalmologist will remove cataracts in each eye at the same surgery. Phacoemulsification is the same technique performed for human cataract removal; the tiny probe breaks up the cataract with ultrasonic vibration and draws out the cataract particles. Many people believe that cataract removal is done with a laser but that is incorrect!! After removal of the cataract(s) your ophthalmologist may suggest replacement of the lens with an artificial lens to obtain sharpter vision as is the case in human cataract surgery.
- Ulcerative Corneal Disease (Corneal Ulcers)
Definition: A corneal ulcer is a break in the outer layer or epithelium of the cornea. Uncomplicated ulcers, although initially painful, should heal in 3 to 4 days with appropriate treatment. Those ulcers that persist longer than this period of time often prove to be complicated ulcers.
Complicated Ulcers
Corneal ulcers fail to heal for two broad categories of reasons. The first category is comprised of those that fail to heal due to external causes. These causes include ongoing trauma such as entropion - an abnormal rolling in of the eyelid, or trichiasis - facial hair which is in contact with the eye as a result of facial conformation. Also, foreign bodies lurking behind the third eyelid, embedded within the eyelid or in the cornea itself, and abnormally placed eyelashes - ectopic cilia - are causes of ongoing corneal trauma. In addition, some breeds of dogs which, due to facial conformation have a decreased ability to blink and spread the tearfilm over the cornea, may develop corneal ulceration due to excessive evaporation of the tearfilm and exposure of the corneal surface. Finally, unresolved infections which may be seated in the conjunctiva, in the glands of the eyelid margin or within the tear duct may cause corneal ulceration.
These corneal ulcers will not heal unless the external cause is treated at the same time as the ulcer is treated.
The second category of non-healing ulcers is those that fail to heal for internal reasons. These causes include other ocular diseases and primary tissue healing problems. Other ocular diseases that would prevent corneal healing would be the lack of tear production, glaucoma, and intraocular inflammation. Primary tissue healing problems refer to conditions in which the tissue itself fails to heal in a normal fashion. This process is recognized in certain breeds, like the Boxer, Samoyed, Corgi but may occur in any older dog and is referred to as an "idiopathic epithelial erosion" Other terms for this type of ulcer is "indolent ulcer" or "boxer ulcer."
Treatment: Treatment of a non-healing corneal ulcer is dependent on the results of the diagnostic procedures. Ulcers that involve external causes require those causes be treated and normally healing rapidly follows. Those that involve other ocular diseases will require those ocular diseases to be treated in an effort to permit healing of the ulcer.
The most frustrating ulcer may be the idiopathic epithelial erosion ulcer (indolent ulcer). These ulcers, although generally not sight threatening, take a long time to heal. Treatment consists of stripping the surface off of the cornea - this is called corneal debridement; scratching the corneal surface with a needle to 'roughen' it - this is called a crosshatch or grid keratotomy (see figure); and then , medications to dilate the pupil and hyperosmotoc agents which increase the adhesion of the epithelial surface layer to the underlying corneal stroma. In some cases, a soft contact lens or a collagen shield is applied to the cornea to act as a bandage. A collagen shield is like a contact lens but will dissolve in 72 hours. If medical therapy doesn't work, a surgical procedure known as a superficial keratectomy is recommended. Third eyelid flaps are generally not as effective in the treatment of this type of corneal ulcer.
- Distichiasis
Definition: Second row of eyelashes (can be complete row or just a few cilia), often inside the line formed by the openings of the ducts of the Meibomian glands - these abnormal cilia tend to fall out and regrow so observe for several months to determine extent of eyelid involved. (Districhiasis indicates that there is more than one cilium growing out of a follicle - commonly seen with distichiasis.)
Can cause ocular irritation with epiphora and even severe corneal disease due to entropion, but most cases are just incidental and are not associated with problems.
Often need oblique illumination and magnification to diagnose.
Most common in dogs; especially cocker spaniels and poodles - heritable.
Treatment: Most cases require no treatment - be sure that the cilia are causing a problem before attempting treatment because complications associated with treatment may lead to problems more troublesome than the cilia.
- Entropion
Definition: Rolling in of eyelid - congenital or acquired - usually leads to trichiasis which can cause severe corneal damage which in turn causes blepharospasm which aggravates the entropion, etc.
Types: Spastic entropion - due to painful lesion of the globe - e.g., keratitis, corneal ulcer; almost always a complication of entropion due to other causes.
Cicatricial entropion - following inflammation, trauma, or surgery of eyelids.
Anatomic entropion - usually congenital, but may become worse as postnatal development progresses; often heritable; seen in all species, but especially foals, lambs, and dogs (chow chow, Shar-Pei, English bulldog, and the breeds used for hunting). Dr. Roy W. Bellhorn (Emeritus, University of California, Davis), has shown that many of these animals have an abnormally long eyelid, particularly the lower. This leads to an abnormal relationship between the cornea (globe) and the eyelids.
Treatment: Always evaluate the problem after topical anesthesia to decrease the spastic component - surgical correction should only involve the anatomic or cicatricial component.
There are many methods of correction, but the simplest and usually most effective is the skin and muscle resection. However, many entropions are not simple (e.g., in the Shar-Pei or chow chow) and require moderately involved procedures to correct. These patients should be referred to an ophthalmologist.
- CIKS - Chronic immune mediated keratoconjunctivitis sicca or Pannus
Definition: It is most common in German shepherds, greyhounds and Siberian huskies. The cause of this condition is not known, at present. This may be an immune response to changes brought on by ultraviolet radiation. This is based on the increased prevalence of the disease at higher altitudes. Usually immune mediated CIKS starts at the outer edges of the cornea as blood vessel infiltration and then pigmentation of the cornea. As the disease progresses it spreads across the cornea to the nasal side of the eye and blindness can result from the condition. The third eyelid may become thickened and depigmented, which makes the eye look even worse. If the disease appears early in life (less than 2 yrs. old) it has a tendency to be very severe as it progresses. When it shows up later in life (4 to 5 yrs. or older) it usually is less severe.
Treatment: CIKS can be controlled with medical therapy, usually very successfully. It can not be cured, however. Medication is necessary lifelong for dogs with this condition. In areas of low elevation, it is usually possible to treat this with corticosteroid . In severe cases, injections of corticosteroids into the tissues surrounding the eye can be necessary. In areas of higher elevation it can be necessary to go to much greater lengths to control this problem. Irradiation of the cornea, surgical removal of the affected areas of the cornea and other measures may be necessary to provide relief from this problem.
- Pigmentary keratitis
Definition: Frequent irritation from dirt or dust can cause chronic inflammation of the conjuctiva and cornea. Initially this is noted as redness and general haziness to the cornea. Left untreated, however, it can progress to scarring and pigment deposition.
An inability to close the eye completely is seen with some neurological problems and also in brachycephalic breeds (pushed in face) whose bulging eyes are not completely covered during a blink. This can result in drying and scarring.
Treatment: Gentocin Dura-Film (a steroid) applied to the eyes daily is useful for the management of some cases of pigmentary keratitis. Some people have also had good results with the use of cyclosporine. A surgical procedure exists whereby the pigmentation is scraped off the eye. However, such a procedure is not of much use unless the underlying cause of the pigmentation is determined first and corrected.
- Progressive Retinal Degeneration / Progressive Retinal Atrophy(PRA)
Definition:Some breeds have blindness by abnormal development of the retina and this is called dysplasia. Other breeds have a slowly progressive degeneration or death of the retinal tissue and this is degeneration. These two types of diseases affect many breeds. In general these diseases are thought to be inherited but inherited differently in each breed.
In all animals with PRD the outcome, age of the patient and what the veterinary ophthalmologist sees are the basis for the classification of exactly what type of condition the patient has. Different breeds of dogs have variations in the age the problem starts and speed with which the blindness develops. The condition of PRD has been seen in almost every registered breed and in mixed breed dogs as well. This same condition occurs in humans and is known as retinitis pigmentosa.
Treatment: There is no possible treatment for PRD although a number of vitamin therapies have been suggested by various people. One such vitamin "Ocuvite" manufactured by Stortz has been recommended for people with retinitis pigmentosa and some patients claim that their vision is improved somewhat. At this time, none of the vitamin have been proven to be effective scientifically, so use of Ocuvite must be deemed a naturopathic remedy rather than a medical treatment. Use of any other megavitamin treatment is discouraged.
As can be seen from the above list, many eye problems have similar symptoms. Only a thorough eye examination can determine the correct diagnosis and the proper treatment. A good routine to get into is getting your dog eyes examined annually by a veterinary ophthalmologist. The exam is very thorough, painless and affordable.
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