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DRY EYE

Dry eye results from a deficiency in the liquid portion of tears. Tears are produced by tear glands around the eye and are spread across the surface of the eye (called the cornea) by blinking. This tear film has several functions:

It lubricates and flushes debris from the eye
It provides oxygen and nutrients to the cornea
It contains anti-bacterial substances to help prevent infection

The most common cause of dry eye is the dog's own immune system mistaking the tear glands as foreign and attacking and destroying them, as it would an invading germ. The progressive loss of these glands results in tear production being reduced. Without the protection of tears, the eyes become dry and irritated, often develop infections and the cornea can become ulcerated. Eventually, the cornea can become permanently scarred, or develop blood vessels and pigments over its normally transparent surface, leading to blindness.

Symptoms

Common signs of dry eye which will alert your veterinarian to the disease include:

Redness of the eyes due to inflammation - your dog may squint and rub at its eyes
A thick sticky yellowish discharge from the eyes
Ulceration of the cornea
A dull or cloudy cornea early in the disease
Blindness due to corneal pigmentation and scarring later in the disease.

Your dog's breed and age also provide important clues.

Dry eye is most common in middle aged and older dogs. The breeds of dog most prone to dry eye are: West Highland White Terrier, Cavalier King Charles Spaniel, Cocker Spaniel, Shih Tzu, Miniature Schnauzer, Pekingese, Bulldog, Pug and Lhaso Apso.

Schirmer Tear Test

This is the diagnostic test for dry eye.

It involves placing an absorbent paper strip, containing a blue coloured indicator, under the lower eyelid for one minute. Any tears produced will be absorbed by the test strip. The blue indicator is carried by the tears along the test strip, thereby showing the level of tear production.

Treatment

Treatment of dry eye may be either medical or surgical. Medical therapy is usually effective and is commonly attempted prior to resorting to surgery.
It may include:

Treatments to increase tear production
Artificial tears.
Antibiotics
Corticosteroids in some situations

The most effective registered therapy for dry eye, is an eye ointment called Optimmune, which contains cyclosporin, an Immune suppressant drug that is also used to prevent transplant rejection in humans.

Optimmune is the only registered product which treats the cause of the problem, not only the symptoms, by:

stimulating the tear glands to resume normal tear production
halting the immune destruction of these glands
helping to reduce inflammation of the eyes

The concentration of cyclosporin in Optimmune is just 0.2%, so it will not affect the immune function af the rest of the dog's body.

Optimmune is usually applied twice daily to the eyes for the remainder of the dog's life. It has been found to be effective in over 80% of dogs with initial Tear Test readings of greater than 2mm. 50% of dogs with readings of less than 2mm respond to Optimmune, therefore early diagnosis is vital.

Using Optimmune

Ensure the eyes are clean before applying Optimmune as mucus and debris can prevent it from working optimally.
Apply Optimmune twice daily, as close to 12 hourly as possible.
If treating both eyes, always treat the "better" one first.
To apply Optimmune, carefully pull down your dog's lower eyelid with one hand. Hold the tube of Optimmune in the other hand and rest it on top of the dog's head to steady yourself. Apply the ointment to the inside of the eyelid and allow the dog to blink to spread the Optimmune over the eye.
Use only a 6mm strip of Optimmune in each eye per application. hsi is similar to a grain of rice in size. Squeeze the tube gently form the bottom- a small squeeze may yield a large amount of Optimmune!
Squeeze to flatten the tube to get the last of the ointment out. Do not roll like a tube of toothpaste as the tube may split.


Pre treatment	Day 7 of Optimmune therapy

Day 21 of Optimmune therapy	Day 63 of Optimmune therapy

Points to remember

Store Optimmune below 25°(. In warm weather, it may help to place the tube in the refrigerator 15 minutes prior to use to "harden" the ointment and prevent wastage.
Do not stop treatment unless told to do so by your veterinarian.
Some dogs may take up to 3 months to respond to treatment initially. Others may look better quickly and it can be tempting to think the problem is "cured" and treatment is no longer required, however, most dogs will require lifelong Optimmune
therapy. If treatment is stopped the symptoms will reappear, and further attack on the tear gland will occur. This leaves less tear gland to produce normal tears when treatment is resumed.
Each tube is manufactured under strict quality control, and has a 7g capacity but contains 3.5g of Optimmune, and has an air bubble at the top. Be aware of this when opening each tube; gently squeeze the tube until the contents appear at the nozzle.
The tube may appear only half full after the air has been expelled - this is normal.
If applying Optimmune to both eyes twice daily, each tube should last at least 6 weeks, when applied at the correct dose.
Finally, remember to visit your veterinarian for regular check-ups as they will want to monitor your dog's progress and perform regular Tear Tests to assess the improvement in tear production. Ensure that the Optimmune is applied to your dog's eyes at least 3 hours prior to your visit. Try to make an appointment at a similar time of the day for each check up in order for your vet to effectively assess the progress of the treatment.

For BVH clients, we refer eye cases to Drs Jeff Smith and Cameron Whittaker at the Animal Referral Hospital, Strathfield, Sydney.


The Animal Referral Hospital referral letter	Map of the Animal Referral Hospital