What is dry eye in dogs?
Dry eye syndrome in dogs, also known as Keratoconjunctivitis Sicca (KCS), involves decreased or inadequate tear production. Tears are produced by the lacrimal, or tear gland, and the gland of the third eyelid. Tears are needed to provide lubrication and nutrition to the cornea, as well as to remove debris and/or infectious agents from the eye. The tear film is a mixture of mucus, fatty liquid, and water.
Any condition that impairs the ability to produce adequate amounts of tear film can result in dry eye. Some of the common contributing causes of KCS include:
- Immune-mediated diseases that damage the tear-producing glands. This is the most common cause of KCS and is poorly understood. The body's immune system damages the cells that produce a portion of the tear film, resulting in decreased production.
- Infectious disease
- Certain medications
- Prolapsed gland of the third eyelid (cherry eye) and/or removal of the gland of the third eyelid
- Damage to the nerves going to the tear glands (neurogenic KCS)
Certain breeds are more likely to develop KCS, suggesting there is a genetic basis. Commonly affected breeds include the Cavalier King Charles Spaniel, English Bulldog, Lhasa Apso, Pug, Shih Tzu, and West Highland White Terrier. However, regardless of breed, any dog can be affected with KCS.
KCS most commonly affects middle-aged to older dogs.
Written by Dr. Mariella Roberts, Veterinary Surgeon, Animal Trust Vets CIC | Published June 2025 | Review date June 2027 | This advice is for UK pets only and is not a replacement for seeing a vet
