Why Are My Dogs Eyes So Red. Red eyes can also be caused by fungal infections. Conjunctivitis in dogs (pink eye) if one or both of your dog’s eyes are red, there’s a chance they have conjunctivitis, aka pink eye.
Just like in humans, a lot of things can cause dogs to get an eye infection. Observing a laceration or similar wound to the eye can be the cause of the redness in the dog's eye. It is red in color because it reflects light as it hits the blood vessels in the retina at the back of the eye.