Glossary
Dry eye
A condition in which a dog does not make enough tears, leaving the eye sore, red and covered with sticky discharge.
Also called: keratoconjunctivitis sicca, KCS, canine dry eye, low tear production
Tears keep the surface of the eye smooth, wash away dirt and feed the cornea. In dry eye, formally keratoconjunctivitis sicca, the tear glands underproduce, often because the immune system attacks them. The eye becomes red, dull and uncomfortable, and a thick yellow or green mucus discharge builds up. Dogs may squint, rub their face or develop corneal ulcers and dark scarring.
Breeds including the Cocker Spaniel, Bulldog, West Highland White Terrier and Shih Tzu are prone. It can also follow removal of the third eyelid gland, a problem with cherry eye surgery.
A vet measures tear production with a simple strip test. It is usually controlled with lifelong care, not cured, so see a vet if an eye has constant discharge, rather than just wiping it.
Last reviewed November 8, 2026