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Dogs like us humans can be plagued with various eye ailments such as retinal diseases, glaucoma, dry eyes, infections, cataracts and swelling. In the case of dry eye, also known as Keratoconjunctivitis Sicca, or KCS, finding the cause isn't always obvious and you may do better to try and prevent any damage the condition can cause. Dry eye results when a dog's eye does not produce enough tears. Taking the time to learn a little bit more about the condition can be helpful in teaching you how to spot the signs of dry eye and to be prepared on how to deal with it, if necessary.
That long scientific name - Keratoconjunctivitis Sicca - actually roughly translates to "the inflammation of a cornea and surrounding tissues due to drying", which is why dry eye is such an apt term, as well as much easier to say. It is the result of an inadequate amount of tears being produced to properly lubricate the eye.
Tears serve a very important purpose, both for humans and dogs. They keep the cornea nicely lubricated and supple while also quite literally washing away and dust or debris that, if left in place may cause irritation to, or even scratch the sensitive cornea. The tear film in a canine eye is not simply a salty, watery thing though, it is a precise combination of mucus, fatty lipids and water. In dogs with dry eye tear film production is reduced to the point that eye injuries begin to occur.
Brian Gilger, DVM and professor of ophthalmology at North Carolina State University (NCSU) College of Veterinary Medicine in Raleigh reports that "around 5% of dogs will have some level of dry eye during their lifetime".
Some of the causes of dry eye are not quite clear to medical science. Some dogs develop it as a side effect of hypothyroidism or canine herpes. The majority however develop an immune reaction that damages the tear duct. Just why that occurs is a still a matter of ongoing research, but the current thinking is that this immune reaction is an inherited trait.
Other causes of the dry eye syndrome in dogs include: sulfa medication, trauma and the surrounding environment a dog lives in. Dogs living in areas where it's dry, windy or dusty are more susceptible to developing dry eye than those living in less extreme conditions.
Dry eye can affect any dog, but there are certain breeds in which it is more common. These include smaller dog breeds like: pugs, westies, terriers, cavalier King Charles spaniels, Shih Tzu, Boston Terriers and English Bulldogs. As you will have noticed a number of these breeds traditionally have rather prominent, protruding eyeballs, so if they develop dry eye it is often far more noticeable.
Dogs with dry eye usually have red, irritated looking eyes. They will often squint, or hold their eyes tightly shut for a few seconds at a time and you may also notice a thick, yellowish discharge from the eyes, which is a result of the lack of tear film production leading to a lack of essential water in the eye.
Dry eye usually affects both eyes, but the symptoms may be more noticeable in one eye when compared to the other. Owners often mistaken that their pets have an eye infection, but it’s really dry eye developing,” Dr. Gilger notes.
In more serious cases, corneal ulcers occur and a pup may develop recurring bouts of conjunctivitis.
In some cases this can lead to the permanent scarring of the cornea, which is seen by the naked eye as a darkish film covering the eye. This scarring can lead to a decrease in vision and eventually to blindness if the condition is left untreated.
Vets commonly make a diagnosis of Dry Eye based on a physical examination in combination with tear production tests. The most frequently used test is called the Schirmer tear test. It involves taking a small strip of a special paper - one with excellent wicking properties - and placing it at the corner of the affected pup's eye for a minute. The film will then show the vet just how many tears are being produced and that number can be compared to a healthy baseline.
Additional tests may be performed to determine the extent of any corneal scarring, to check for corneal ulcers and to ensure the glaucoma, which is a different disease of the eye, is not present as well.
Dry eye can have a dramatic impact on a dog’s quality of life, so it's important that owners get the condition diagnosed and treated as early as possible.
Any treatment for dry eye syndrome in dogs has two big goals: to increase the production of healthy tears and to slow the damage to the eye by restoring the tear film that is supposed to be protecting it.
The two most popular, and commonly used medications to treat dry eye are cyclosporine and tacrolimus. When these are given on a regular basis most dogs will show an improvement within days.
In some more serious cases, when perhaps the administration of drugs is difficult a newer surgery may be considered that seeks to correct the issue permanently. This is achieved by moving a salivary gland so that it secretes saliva into the eye. This is a complex process though that comes with a number of risks and so is usually only recommended as a last resort - however it is a very effective one, Dr. Gilger writes.
For most dogs being treated with medication for dry eye the prognosis is very good. The drugs are provided in dropper form and, with a little practice, you should find that they become relatively easy to administer. Depending on the severity of the original disease they will need to be administered about every 4-6 hours on a daily basis.
You can also help a dog being treated for dry eye wiping their eyes once a day with a warm, clean damp compress to help keep their eyes as clean as possible while also providing some comfort - and bonding time.
As to whether any damage to a dog's vision as a result of dry eye can be reversed depends upon the extent. Some minor corneal scarring in young dogs will often eventually heal, but more extensive scarring, especially in older dogs, may leave them with decreased vision. However, if the medicines are given on an ongoing and regular basis any future damage is usually prevented.