Breeding with Integrity

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Eye Diseases of the Black Russian Terrier

Like most breeds of dogs, the Black Russian Terrier can be susceptible to a variety of eye diseases or conditions. Some are genetic or inherited, while others may be acquired. Some have the potential to be quite serious and others can be nothing more than a nuisance.

Following are some eye problems that may occur in your BRT, along with their descriptions, and what you can expect and should do. I am not a veterinary ophthalmologist but am passionate about eye diseases and cases, and perform a wide variety of eye procedures, from simple growth removals to delicate corneal graphs. After seeing and treating a significant number of canine eye problems over two decades, I hope this article is informative and useful in helping you consider what might be affecting your BRT should any of these conditions arise, and to know when to seek veterinary or specialist care as needed.

Conditions discussed in this article:
  1. Distichiasis and Trichiasis

  2. Entropion

  3. Progressive Retinal Atrophy

  4. Eyelid Growths and Cherry Eye

  5. Corneal Ulcers

  6. Glaucoma

  7. Red Eye

Distichiasis and Trichiasis

Distichiasis and trichiasis are not generally considered serious.
  • Distichiasis is a condition in which eyelashes grow from the tarsal glands (sebaceous follicles between the cartilage and conjunctiva of the eyelids) in an improper
  direction, often growing backward towards the cornea. This is considered a commonly inherited disease among many breeds. If present, it will be found and noted by
  board certified veterinary ophthalmologists during Canine Eye Registration Foundation (CERF) exams.

  • Trichiasis occurs when eyelashes grow from the tarsal glands in the proper orientation, but become directed or curl backwards towards the eye.

The net effect of these conditions is irritation to the cornea, which may present itself as a red, irritated eye with discharge, blepharospasm (squinting), and discoloration of the cornea from chronic irritation or even ulceration of the cornea.

Treatment is directed at removing offending eyelashes. This may be as simple as plucking the lashes (they will frequently regrow); removal of eyelashes via electrolysis to try and prevent regrowth; cryotherapy (freezing the eyelid margin) to remove abnormal lashes and prevent regrowth; or even surgery to remove a portion of the eyelid containing abnormal eyelashes (not usually necessary).

entropion

Entropion in a dog: Note the inward rolling of the eyelids

Progressive Retinal Atrophy (PRA)

Progressive retinal atrophy describes a collection of conditions affecting the canine retina. It often presents as a chronic, slowly progressive deterioration of the cells of the retina, eventually leading to blindness.

The age of onset is variable but usually occurs in young adult dogs. Owners will often first notice vision problems at night or during low-light situations. The dog may seem hesitant to go down stairs or may start bumping into things. Often, the pupils will remain dilated. The length of time from onset of symptoms to complete blindness is variable, but usually will occur within one year.

How is it diagnosed? An ocular exam by a veterinarian or ophthalmologist will reveal a slow pupillary light reflex and hyper-reflexic retina. A fundic (retinal) exam will show a thin retina with attenuated (shrunken) or absent blood vessels. The ocular nerve may be pale. A referral to a veterinary ophthalmologist will likely be recommended to confirm the diagnosis. Most veterinary ophthalmologists readily recognize changes present with PRA; however, an electroretinogram (ERG) can confirm the diagnosis.

Is there a cure? Unfortunately, there is no known effective treatment for PRA in dogs. If your dog is diagnosed with PRA, you should begin to make preparations to assist your companion as his vision fades. A safe home environment for a blinding dog is important. You may also want to work on games that involve noise or smell to help hone your dog’s skills and help him adapt to his decreasing vision. It is important that the environment stay consistent – do not rearrange the furniture!

Newer research shows an antioxidant supplement marketed as Ocu-GLO RX™ (www.ocuglo.com) may aid in the slowing of the retinal degeneration and delay the onset of blindness in canine PRA. I have no experience with this product, but with no other treatment options available it is likely worth trying; however, I recommend first consulting your veterinary ophthalmologist.

Several breeds known to have high incidence rates of PRA have had DNA tests developed to help diagnose PRA before dogs are bred and the trait passed on. Most PRA conditions are passed on via an autosomal recessive gene and can quite easily be bred against – although this is not true in all breeds. As of 2012, I have found no references to the mode of inheritance of PRA in Black Russian Terriers or any literature as to what the incidence rates may currently be. I do know of one affected BRT, however, and suspect it is occasionally seen but likely not often reported. A true incidence rate may never be known.

normal canine retina

Normal canine retina

Canine retina with PRA

PRA retina

Eyelid Growths and Cherry Eye

Growths on the eyelids of dogs are not uncommon. Most are nothing more than a nuisance; however, some types can be malignant and others may get large enough to rub on or damage the cornea.

The most common eyelid growth is a meibomian gland adenoma. This is a benign growth arising from one of the glands located at the margin of the eyelid. Most of the time these do not get very large, but sometimes they may angle toward the eye and rub the cornea, necessitating their removal.

Another growth you may note on the eyelid is the chalazion. This is actually a blocked gland better known to people as a stye. These will only need to be treated if they are bothering the dog. Sometimes they will respond to warm compresses. If not, they may need to be lanced or surgically removed.

There are many other growths that may arise on the eyelids, such as mast cell tumors, melanomas, and squamous cell carcinomas, among others. These have the potential to be very serious and require surgical removal and possibly other adjunct treatments.

Bottom line: If you notice a growth on your BRT’s eyelid, have it checked such that treatment can be performed if necessary.

Cherry eye is a term used to describe the prolapse of the gland of the third eyelid. When this gland prolapses, you will notice a red bulge at the medial canthus (the corner of the eye by the nose). Sometimes if it is a recent prolapse, the gland can be gently pushed back in to place; however, often the cartilage stalk that attaches to the gland becomes bent, causing the gland to immediately re-prolapse.

There are two treatment options for cherry eye:

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  • The first and preferred procedure is to surgically reposition the gland back into place. The cartilage stalk is severed to prevent the gland from popping back out. This is a delicate surgery that may be referred to a veterinary ophthalmologist for the procedure.
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  • The second procedure involves completely removing the gland. The dog is sedated, the gland is numbed and clamped, and then excised with surgical scissors. The procedure is fairly simple and quick; however, some eyes may not produce enough tears following removal of this gland, necessitating the use of eye drops or tear stimulators.
  •  
  • My preference is to reposition the gland; however, due to financial constraints on many clients, I have performed many excisions as well. I have very rarely encountered inadequate tear production following gland excision.
Cherry Eye

Appearance of Cherry Eye

Corneal Ulcers

The cornea is the thin clear layer of the eye enveloping the anterior chamber of the globe. The cornea is frequently injured due to rubbing or trauma to the eye. Any damage to the cornea will usually present as a painful, red, uncomfortable eye. You may or may not be able to see the injury depending on its size.

A corneal injury can be as simple as a small scratch, or a much larger defect that could lead to perforation. You will often note the dog squinting or pawing at its eye when a corneal injury is present.

Due to the delicate nature of the cornea, and its importance to the eye and maintaining good vision, any time a corneal injury is suspected it should be treated as an emergency and be seen by the veterinarian as soon as possible. The veterinarian may need to perform a fluorescein dye test to highlight the injury if it is not readily apparent. Most corneal injuries will heal with just supportive treatment. Generally, a topical antibiotic will be used, as well as oral pain medicine for discomfort. Corneas can be slow to heal, though, due to the lack of a blood supply (the cornea will actually grow small blood vessels to heal the injury). A new medicine called Remend™ can help speed corneal healing.

Sometimes the cornea may fail to respond to treatment and more advanced procedures may be needed to stimulate healing. If it is deemed the cornea may be in danger of rupturing, a corneal graph may be placed to immediately add strength and healing to the injured eye. Frequent rechecks will often be recommended to assess progress of the corneal healing.

Corneal Ulder

Fluorescein dye showing a corneal ulcer

Glaucoma

Glaucoma is defined as an increase in the intraocular pressure (the fluid pressure inside the eye). It can be present in one or both eyes, and can be acute (occurring very rapidly) or chronic. Normal eye pressure in a dog is approximately 15 mmHg (millimeters of mercury) but may range from 10-30. Anything over 30 mmHg is considered glaucoma and should be considered an emergency. An eye pressure persistently elevated over 40 mmHg can cause blindness in as few as 48 hours.

Appearance: A glaucomatous eye will generally appear to be red and painful. It may take on a buphthalmic (enlarged/bulging eye) appearance, and the cornea may appear hazy.

Causes: Glaucoma can be genetic (primary) or acquired (secondary). I have found no references to primary glaucoma in the Black Russian Terrier. Cocker Spaniels, Beagles, Samoyeds and several other breeds have primary/genetic glaucoma in their lines. Secondary glaucoma can be seen in any dog and be a result of a variety of causes, including: trauma, uveitis (inflammation or infection of the uveal layers of the eye), displaced lens, and neoplasia, among others.

  •  
  • The diagnosis of glaucoma is straightforward. Eye pressure is measured and anything over 30 mmHg is considered positive, although the root cause of elevated pressure may not be readily apparent.
  •  
  • Treatment focuses on lowering eye pressure. If cause can be determined and corrected, that is the focus of treatment. If no primary cause is determined, there are medical and surgical treatment options.
  •  
  • Medical management is the most common and preferred modality. This may consist of a variety of medicines, oral or topical, designed to decrease fluid production in the eye, decrease pain and inflammation, and speed fluid removal from the eye. Medical therapy will often be a lifelong endeavor. It is difficult to continuously keep eye pressure down, thus keeping the eye comfortable and visual.
    • There are several surgical options for the treatment of glaucoma with variable success rates. Most commonly, these procedures try to improve the drainage of the aqueous from the eye, thus reducing pressure; however, unfortunately, even with prompt diagnosis and treatment, a lot of times a glaucomatous eye will become a blind eye. If pressure continues to elevate, it will be a blind PAINFUL eye. In this situation, chemical ablation (injecting gentamycin into the eye to prevent fluid production, thus permanently ending the glaucoma), or enucleation, should be considered for the comfort of the dog. An intraocular prosthesis can be placed if desired.

Acute Glaucoma

Acute Glaucoma

Chronic Glaucoma

Chronic Glaucoma

Red Eye

Red eye is simply the term given to describe the many conditions described above – plus others – in which the canine eye becomes inflamed and/or red. After reading about the above eye diseases, it should be readily apparent that a red, irritated eye could be brought about from a number of diverse conditions. Things as minor as allergies, or as dreadful as glaucoma, or a deep corneal ulcer, can produce a red irritated eye. If you ever find your BRT to have a red eye or eyes (assuming you can see your BRT’s eyes!), it is quite important to have a veterinarian assess it. Most likely it will be something minor and easily treatable; however, much more significant and serious problems may be present as well that you will want to know about and seek preventive or proper treatment.

It may be very difficult for you to determine what is causing irritation or redness. With the delicate nature of the canine eye, a prompt and thorough eye examination by a veterinarian is certainly warranted.

Here’s looking at you!

Respectfully,

Richard Hawkes, DVM