Red Eye is common in Dogs and Cats and is a form of Cherry eye, glaucoma, Uveitis, Keratitis, cataracts, Scleritis, or Conjunctivitis. Conjunctivitis is the eye problem which reddens the mucous membrane of the pet’s eyes. Certain fungi or viruses are the root cause for Conjunctivitis in dogs and cats. Parasites such as ticks and other body allergies can sometimes cause these eye problems of pets. If your pet has red eyes it may require immediate treatment with eye drops or surgery in extreme cases to cure conjunctivitis in pets.