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KERATOCONJUNCTIVITIS SICCA ("DRY EYE" or KCS)

Note for Pet Owners:

This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

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Description
Keratoconjunctivitis sicca (also known as KCS or "Dry Eye") is a common disease in dogs, but rare in other species. It is caused by a lack of tear production and can affect one eye or both eyes.

Cause
The disease is a lack of tear production and may be caused by a number of factors : 

  • An autoimmune disease - the animals own defence system damages the tear producing (lachrymal) tissue
  • Iatrogenic causes - due to toxic effects of drugs including :
    • Sulphonamide antibiotics
    • H2-receptor blockers (eg cimetidine)
  • Unknown (idiopathic) causes

Breed Occurrence
Small breed dogs are most often affected including the Boston Terrier, Miniature Poodle, Cocker Spaniel and middle-aged, female West Highland Whites are reported to be particularly susceptible.

Signs
The disease usually affects one eye initially, but involves both eyes. Clinical signs include :

  • Thick, sticky discharge from the eyes
  • "Red eye" redness of the conjunctiva due to inflammation and increased blood supply (hyperaemia), and occasionally black pigmentation
  • The usually clear surface of the eye (the cornea) becomes opaque , and small new blood vessels grow across it. In longstanding cases there may be black pigmentation and  ulceration of the surface
  • Affected dogs often cannot open their eyelids fully.
  • Some dogs rub their eyes 

Complications
Severe ulceration of the cornea can lead to rupture of the eyeball.

Diagnosis
The diagnosis is confirmed by using a Schirmer Tear Test - this paper strip absorbs moisture and so measures the amount of tears on the surface of the eye. The strip is left in contact with the eye for 1 minute and a reading of over 15 on the scale is regarded as normal. Readings of 0-5 are diagnostic for KCS. 

Treatment
There are several forms of treatment  that are used :

  • Cyclosporin
  • Artificial tears (hypromellose, methylcellulose)
  • Pilocarpine 1% - oral administration
  • Corticosteroids - should be used with caution if ulceration is present
  • Surgery - transplantation of the parotid salivary gland duct has been successful in the past  but has been supereceded by the use of cyclosporin.

Prognosis
The prognosis is good in most cases, providing sever ulceration is prevented.

Long term problems
 Chronic pigmentation can lead to functionally impaired vision.

 

Updated October 2013

 
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