Keratoconjunctivitis sicca, also known as dry eye, describes inflammation of the cornea and conjunctiva caused by insufficient or completely absent tear fluid, which in severe cases can lead to blindness.
In dogs, two different glands are responsible for producing the tear film, one of which is not visible in the upper part of the eye socket. A second gland is located in the dog's third eyelid, known as the nictitating membrane. The tear fluid is made up of several components that are distributed evenly over the eye by blinking. The various components of the tear fluid protect the eye, remove dirt, dust and infectious agents, and nourish the cornea.
Keratoconjunctivitis sicca is caused by insufficient or absent tear fluid production, which can have various causes. If one of these two glands is injured or damaged by infectious diseases, toxins, medication, or vitamin deficiency, tear fluid production is disrupted, preventing the eye from being adequately rinsed and cleaned. Small dog breeds such as Yorkshire Terriers, Beagles, Miniature Schnauzers, Pekingese, Lhasa Apsos, and Cocker Spaniels are genetically predisposed to developing KCS. A familial predisposition has been scientifically proven in West Highland White Terriers. In many cases, malfunctions of the body's immune system lead to continuous destruction of the tear glands, triggering KCS. This is referred to as an autoimmune disease, as the immune system attacks the body's own cells.
Both eyes are often affected, although the condition can occasionally occur in only one eye. The lack of tear fluid causes the eye to dry out. Affected animals therefore usually only show increased blinking at first. As the disease progresses, the conjunctiva becomes reddened and inflamed, with a grayish, thick discharge from the eyes. Unlike normal conjunctivitis, KCS is extremely painful for dogs, which is why they often squint their eyelids.
In advanced stages, the lack of protection of the eye from mucus, dirt, and bacteria leads to painful inflammation of the cornea, which becomes dull and uneven. The ingrowth of blood vessels and the resulting deposits of pigments and inflammatory cells cause the clouding of the cornea to progress until it eventually leads to blindness. The eye is swollen, thick mucous or purulent discharge forms, and the animals suffer from itching. If the eye is not treated in time, corneal ulcers can develop, which in the worst case can lead to a rupture of the anterior chamber of the eye.
Tear fluid can drain through the tear duct, which is why the nostril on the same side of the affected animal often appears dry and crusty in KCS.
After a thorough clinical examination and review of the preliminary report, the attending veterinarian can usually make a preliminary diagnosis. However, a special examination of the eye is necessary to distinguish the disease from other inflammatory changes in the eye. The attending veterinarian can determine the amount of tear fluid using a simple test that is completely painless for the animal, known as the Schirmer tear test. It is important that the eye has not been treated with other medications beforehand. To perform the test, a special test strip is placed in the lower eyelid and after one minute, the amount of tear fluid is read on a scale. The amount of tear fluid reliably indicates whether or not the eye is "dry."
Treatment for KCS must be lifelong and consistent, as the disease itself is incurable.
In the first instance, the symptoms of acute inflammation are treated. Depending on the extent of the changes and bacterial involvement, the veterinarian will use anti-inflammatory and antibiotic eye ointments or drops. Once the inflammation has healed, this therapy is discontinued.
Long-term medication includes artificial tears to clean and moisturize the eye, as well as preparations that stimulate the body's own tear production and slow down the overactive immune system. This can counteract the progressive destruction of the lacrimal glands.
Another treatment option is surgical relocation of the parotid gland's excretory duct to the conjunctiva of the affected eye. This surgical method is not simple and is therefore reserved for specialists. It is performed under an eye microscope and is used in particular for rapidly progressing diseases that do not respond to drug therapy. The disadvantage of surgery is that the saliva contains too much calcium, which leads to irritation of the cornea. In addition, there is constant tearing when the dog is waiting for its food.
As the disease is incurable, the prognosis is poor. However, with appropriate, consistent long-term treatment, the progression of the disease can be delayed and the animal can still enjoy a good quality of life.
Due to the genetic and autoimmune causes of KCS, this condition can hardly be prevented.
However, creating optimal environmental conditions can help ensure that existing conditions do not worsen unnecessarily. This includes ensuring that the indoor climate is not too dry and avoiding heating, wind, sun, and dust.
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This condition, also known as "cold tail," has been known for some time but remains largely unexplored. It occurs mainly in the summer months, is characterized by a distinctive tail posture, and is very painful.
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For many horse owners, this is a sad moment. The diagnosis "unrideable" abruptly ends the dream of experiencing more wonderful moments in the saddle with your horse. But even if riding is no longer possible, the horse should not be any less valuable as a friend. After all, there are wonderful alternatives for spending time together.
For horses, which are flight animals, the eye is an important sensory organ, but it can also be very sensitive to internal and external influences. Conjunctivitis is one of the most common eye disorders in horses. It can occur as a separate disease or as a result of a general illness.
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A cat can have kittens twice a year. Unfortunately, unneutered stray and outdoor cats are often pregnant, resulting in too many "unwanted" cats being born. In some areas, cats that appear to be homeless are caught and taken to the local animal shelter, where they are neutered by a veterinarian. However, if the birth was planned and takes place in a safe environment, it can be a wonderful experience for both the mother cat and her kittens.
