Eye marks in vertebrates as aids to vision.
D000065:Accommodation, Ocular; D000818:Animals; D001717:Birds / Q000033:anatomy & histology; D003463:Cues; D004215:Distance Perception; D005123:Eye; D005247:Feeding Behavior; D014714:Vertebrates / Q000502:physiology*; D014785:Vision, Ocular