What causes read dilated vessels in a child's eyes, looking like pink eye?
Lots of choices
Assuming it's not actually an infection, the next most likely would be an irritating foreign body or allergies.
Could be a variety of other conditions, some of which are serious, so if it persists, a real exam would be the way to go.
PINK EYE (CONJUNCTIVITIS)
PINK EYE (VIRAL CONJUNCTIVITIS)