Protect your dog from keratoconjunctivitis sicca
Our dog’s eyes connect them to the world. They help them bond with other dogs and humans and ensure they have the confidence to navigate their environment. Unfortunately though, from time to time, they may experience issues and ailments that can impact their eye health. One such issue is keratoconjunctivitis sicca, also known as dry eye. In this blog we tell you everything you need to know about the condition, including how it affects your pet and how it can be managed.
Free Schirmer Tear Tests Throughout November
We’re offering free eye consultations for at risk breeds throughout November to help identify dry eye early to limit the damage it has on your dog’s long term eye health.
What is dry eye?
Dry eye or keratoconjunctivitis sicca as it’s medically known, is a painful condition where dogs are unable to produce enough tears. To help understand the condition, it’s worth explaining why our dog’s tears are so important.
Tears are important as they:
- Provide lubrication to the eyelids when they close
- Provide nutrition to the cornea and conjunctiva
- Help protect the eye against infection
- Flush away debris from the surface of the eye
- Stop the eye drying out
On the contrary, if your dog doesn’t create enough tears then problems can occur, including:
- Itchy and inflamed eyes
- A thick, mucoid discharge. This may be yellow/green in colour
- Regular infections (bacterial conjunctivitis)
- Corneal ulcers as the healing ability of the eye reduces
The outlook for a dog with dry eye tends to be good if the condition is noticed early and treatment is continued for life.
What causes dry eye?
Usually, the cause is your pet’s own immune system attacking the very glands that produce tears. However, other causes include chronic infection, previous surgery (eg cherry eye surgery), trauma or previous medication (eg trimethoprim-sulphonamide). We occasionally see problems associated with nerves that stimulate tear production and congenital issues where pets are born without the necessary tear glands.
Is my dog at risk?
All dogs can develop dry eye, but there are a number of breeds that are at an increased risk. Breeds that are more likely to develop the condition include:
- Poodle and Poodle cross
- American Cocker Spaniel
- Boston Terrier
- Cavalier King Charles Spaniel
- English Bulldog
- English Springer Spaniel
- Lhasa Apso
- Miniature Schnauzer
- Shih Tzu
- West Highland White Terrier
- Yorkshire Terrier
How is dry eye diagnosed?
A thorough clinical examination will often give an indication that the eye may not be as healthy as it should be. The cornea will often appear less shiny, whilst the patient may have experienced several bouts of conjunctivitis that temporarily respond to antibiotics and/or lubricant but then return within a few days or weeks of stopping treatment.
Definitive diagnosis is based on a test called the schirmer tear test. This uses a special strip of blotting paper which measures tear production over one minute. If tear proaction is less than 10mm of wetting in 1 minute, we can make a diagnosis of dry eye. Those pets with production of between 10 and 15mm are classed as borderline cases and will be carefully monitored with repeat testing.
Some pets have no tear production at all and unfortunately this carries a worse prognosis.
How is dry eye treated?
The good news for the majority of dry eye cases in dog is that the condition can be managed with a range of medication. Treatment is centred on:
- Tear replacement therapy in the form of eye drops to help with the lubrication and to stop the eye drying out.
- Unfortunately owners can rarely apply them frequently enough and even if they do, false tears are never as good as the real thing
- Blocking the immune destruction of the tear gland – trying to preserve the function of the remaining gland is really important
- Stimulating tear production – certain medications stimulate the remaining glandular tissue to produce more tears
- Reduce secondary problems such as corneal pigmentation or infection with additional drops where needed
The mainstay of treatment is with cyclosporin (0.2%) available in a licensed preparation called Optimmune. If after 6 weeks, the response to treatment is not sufficient, we may use a drug called Tacrolimus. Lubricants such as hyaluronic acid and arbiter gels are also very helpful.
What happens if dry eye is not treated?
If dry eye is not noticed soon enough, it can have a severe impact on your pets quality of life. Patients will develop regular and recurring infections in the eye that don’t respond to treatment effectively. The clear cornea can become cloudy with a leathery appearance with blood vessels growing within it. Sometimes this can cause pigment to be deposited in the previously clear cornea, eventually leading to the vision being compromised. Deep ulcers may also develop on the most severe occurrences, leading to the eye bursting and therefore needing to be removed.
What happens if medical treatment fails?
If medical management fails then in some patients we can consider surgery. The most common surgery ‘hijacks’ a salivary gland and re-routes it into the eye. The surgery is called a parotid duct transposition. The saliva produced by this gland then wets the eye, keeping it comfortable and reducing the chance of life-threatening complications.
This is not a perfect surgery and often requires supportive treatment and management to prevent the area around the eye from getting too moist or infected.
Can Dry eye be cured?
Unfortunately, a cure for dry eye is rarely achieved. Most patients require life long treatment including lubrication and either Optimmune or Tacrolimus. Response to treatment may reduce over time. Long-term, dedicated owner management and veterinary support are therefore required.