Ophthalmology Canine Conditions

Corneal Ulcers

A mild corneal ulcer

A corneal ulcer is a scratch or abrasion on the outside clear part of the eye and is usually caused by trauma. This clear portion of the eye, called the cornea, is composed of many layers. When the cornea is scratched, cells are lost leaving a defect, which is known as an ulcer. Ulcers usually heal rapidly without complications. However, an ulcer may become worse if neglected, treated improperly, or if normal healing becomes interfered. In severe cases, an ulcer can lead to loss of the eye.

Advanced corneal ulcer

Symptoms
Common signs that a corneal ulcer is present include: squinting (due to pain), a “red eye”, excessive tearing, rubbing or pawing at the face, and often an ocular discharge.

Treatment
Preventing infection and controlling pain are the two most important features of treatment. Topical antibiotics will be used to prevent infection and topical atropine may be used to help control pain. If a condition exists that interferes with normal healing, it may also require treatment. It is extremely important to follow all medication instructions.

Your pet may want to rub or scratch at its eyes or face, especially after applying the medications. If the problem occurs for a few minutes after the eye medication has been used, distract your pet by playing with or petting him/her. If the problem continues or if severe rubbing occurs, please contact us or your regular veterinarian to obtain an Elizabethan collar.

Cataracts

Moderate cataract

A cataract is any opacity (cloudiness) of the lens of the eye. If the opacity involves a significant portion of the lens, your pet may exhibit visual difficulty. Trauma, metabolic diseases such as diabetes mellitus, congenital (birth), hereditary, aging changes, or other eye disorders may be responsible for cataract formation.

Symptoms
Cataracts may cause the pupil to appear white or cloudy. Depending on the severity of the cataract, vision may be decreased or the affected eye(s) may be blind.

Treatment

Advanced cataracts

If your animal is a candidate for cataract surgery, the surgery is 85-90% successful in recovering vision. The surgery requires general anesthesia and is often performed on an outpatient basis. The procedure for cataract removal in your pet is similar to small incision cataract surgery in people. Phacoemulsification (fako-emul-sif-ica-tion) uses high frequency sound waves to fragment the cataract into small pieces and permits aspiration from the eye. Once the cataract is removed, it does not recur. There are many inquiries about laser surgery for cataracts. This is a misunderstanding; lasers are not used for cataract removal, but for some complications that occur after cataract surgery has been performed. Some animals have an abnormally positioned lens, which may not allow for phacoemulsification. In these cases, the lens is removed in one piece through a large corneal incision.

An artificial lens implanted in the eye to replace the cataract lens is an option for most of our patients. The purpose of the artificial lens is to help focus light rays which result in a sharper image for the eye. Animals can see without an artificial lens. However, the image the eye perceives will not be in focus. Discussion with your pet’s ophthalmologist will help you determine if your pet would benefit from an artificial lens.

Glaucoma

Early glaucoma

Glaucoma is a group of diseases where the pressure inside the eye is too high and is causing damage to the eye. Glaucoma is the result of a decrease in the ability of fluid inside the eye to flow out of the eye (similar to a clogged drain in a sink). This is very serious and is often a painful disease that leads to blindness, especially if not treated early and properly. Glaucoma is one of the leading causes of blindness in animals and people.

Symptoms
The signs depend on the severity of the disease and how long the problem has been present. The typical signs are a painful, red eye with a dilated pupil. Pain may be demonstrated by depression, tearing, rubbing the eye or face, squinting or holding the eye closed, or a change in appetite and attitude. The eye may be blind, but if only one eye is currently affected this may be difficult to detect. With time, the eye will stretch and enlarge in size.

Treatment

Advanced glaucoma

Depending on the amount of damage to the eye and the type of glaucoma, glaucoma may be treated with drugs, surgery, or a combination of both. Medical treatment (drugs) consists of a number of different medications frequently used in combination. Some are given by mouth and affect the entire animal, while others go directly on the eye for a more local effect. Drug therapy will not control most glaucoma cases long-term, and progressive damage to vision can go undetected. Therefore, it is extremely important to monitor glaucoma on a regular basis so that therapy can be altered as needed.

Surgical procedures for glaucoma in a visual eye can include either improving the ability of fluid to drain from inside the eye, or reducing the amount of fluid that is produced. These procedures include laser surgery, filtering procedures, glaucoma valves and freezing techniques. Sometimes these are used in combination. None of these surgical procedures offer permanent control of the pressure, since glaucoma is a progressive disease. It will gradually get worse no matter what treatment is used. The goal of treatment is to retain vision and maintain comfort for as long as possible. Some of these procedures can be repeated as needed. In a permanently blind eye, the goal of treatment is comfort. This can be achieved by removing the eye, placing a silicone prosthesis inside the eye for a more cosmetic appearance, or injecting a drug into the eye to stop fluid production. Each procedure has advantages and disadvantages, which will be discussed with you.

Eyelid Tumors

Small eyelid tumors

Eyelid tumors are very common in older dogs and the majority are benign (non-cancerous). These tumors often arise from glands that line the eyelid margins. Most of the time these tumors do not cause problems, but if irritation is involved they can be easily removed.

Symptoms
These often appear as a mass affecting the edge of the eyelid. Some can be quite large and affect a significant portion of the eyelid, while other may be relatively small.

Treatment

Very large, advanced
eyelid tumor

There are two methods used to remove an eyelid tumor. One technique is to use a local anesthetic to remove as much of the tumor as possible, then freeze the tumor site (cryotherapy) to kill any tumor cells left behind. This first method is often very effective, and may be repeated if necessary. If the tumor continues to grow despite the cryotherapy, or if the tumor is very large, then an alternative therapy is needed. This second method involves anesthetizing the patient and removing a wedge of tissue with the tumor and then suturing the lid back together.

“Cherry Eye”

Typical appearance of
Cherry Eye

“Cherry Eye” is a common term describing hyperplasia (increased size) and prolapse (displacement) of the gland of the third eyelid. The problem occurs primarily in dogs, but can occur in certain breeds of cats. It is most commonly found in young Cocker Spaniels, Beagles, English Bulldogs and Mastiffs, but can occur in many other breeds. The gland of the third eyelid is a lacrimal gland, meaning it produces tears. The gland is responsible for 30-50% of the tears in a dog’s eye. When the gland is prolapsed, it does not function properly and tear production can decrease. If left in a prolapsed position, the gland can become extremely enlarged and inflamed causing irritation to the surface of the eye.

Symptoms
This commonly appears as a red mass at the lower inside corner of the eye. It arises from the third eyelid (a thin membrane at the inside corner of the eye), and if the gland is severely inflamed it can look like a “Cherry”.

Treatment

Detailed view of
Cherry Eye

A simple surgical technique is available to reposition the prolapsed gland. It requires a short duration of general anesthesia and can be done on an outpatient basis. The patient is usually required to wear an Elizabethan collar for a few days to prevent rubbing of the eyes. Topical antibiotics are required for several weeks after surgery. The surgical site will be red and mildly swollen for several weeks, but is usually comfortable. The success rate for repositioning the gland of the third eyelid is about 90% with a few exceptions. Extremely enlarged glands have an increased risk of re-prolapsing and may require partial amputation to reposition. Certain breeds are also of increased risk of re-prolapse, especially the Neopolitan Mastiff.

Entropion

Note the rolling in of
the lower eyelid

Entropion is an inward rolling of all or part of the eyelid, such that the eyelashes irritate the cornea and conjunctiva (coating membrane). This can cause chronic inflammation and pain (as evidenced by redness, discharge, excessive tearing and spasm of the eyelid) as well as result in permanent scarring, blindness and possible loss of the eye.

Symptoms
Entropion can cause chronic inflammation and pain (as evidenced by redness, discharge, excessive tearing and spasm of the eyelid) as well as result in permanent scarring, blindness and possible loss of the eye. If closely examined, the edge of the eyelid can be seen “rolling in” toward the surface of the eye.

Treatment
The most successful treatment in an adult is surgical correction to reposition the eyelids into a more normal position. In young animals, “temporary tacking” of the eyelids may be appropriate until the animal reaches adult size and conformation. While every attempt is made to correct the problem with the first surgery, it is not unusual for some individuals to require more than one surgical procedure to achieve optimal results. This often depends on the breed of dog and the severity of the condition.

Keratoconjunctivitis sicca

Note the brown crusts
around the eye

Keratoconjunctivitis sicca KCS (“Dry Eye”) is due to a lack of tear production. The deficiency may be mild to severe, and temporary or permanent. The problem may be gradual in onset or very rapid. It usually affects dogs, but cats can occasionally have KCS. It is also common in people.

Symptoms
A thick, sticky mucous discharge from the affected eye(s) is frequently evident. The discharge improves temporarily with almost any treatment placed in the eye, but reoccurs when treatment is stopped. The area around the eye itself is usually red and the cornea (the clear part of the eye like a window) may become heavily scarred, causing blindness. Most animals are uncomfortable and will demonstrate this by rubbing their eyes and face on almost anything. They will also frequently squint.

Treatment

KCS

The best treatment is to stimulate tear production. This is accomplished by using a drug called Cyclosporine A. It is available commercially as an ointment (Optimmune), or can be specially formulated by a pharmacist into a drop. It often takes a minimum of 3-4 weeks to see a response to this treatment, and in the interim, artificial teardrops and ointments are often used. Side affects are rare and are primarily seen as a “stinging” sensation causing the pet to rub the eyes. We also use topical antibiotics and occasionally corticosteroids to control scar formation. In some patients a drug called Tacrolimus may also be used. The key to controlling KCS is to be diligent in using the prescribed treatment. The most common cause of treatment failure is not following treatment instructions, or stopping treatment.

Depending on the cause of KCS, it may be a temporary problem that will improve with time and treatment. However, it is usually a life-long problem that cannot be cured, only controlled. If the problem is permanent and not controlled with topical medications, there is a surgical treatment that will help control the problem. This is called a parotid duct transposition (PDT). It involves moving a salivary duct from the mouth to the eye, so that saliva is delivered to the eye to help keep it moist. It is not a perfect replacement for tears, but can be an adequate substitute. There are some problems associated with a PDT. The face tends to stay wet since the patient cannot control “tearing”. Some animals will require frequent feedings to stimulate salivation, and can gain weight. There can also be an accumulation of minerals from the saliva on the eyelids and eyes.