My dog may eat too much salt, has tear stains and occasional weeping; sneezes when going out. What is the red thing in its eye?

Red thread-like lines in a dog’s eye are usually bloodshot vessels, which many small breeds have. If the vessels thicken it may relate to capillary blood pressure or internal inflammation.

If your dog’s diet is salty and rich, it likely causes ‘heat’ that increases discharge and tear stains, leading to more visible eye vessels. Feed a natural dog food and avoid greasy, high-salt food.

If the moving parasite is suspected, it is likely the eye worm (Thelazia), usually milky white and thin like a thread. Infection causes red, swollen eyes and corneal inflammation, so seek veterinary examination and treatment promptly.