柯林斯詞典optic nerve 1. N the second cranial nerve, which provides a sensory pathway from the retina to the brain 視神經 返回 optic nerve劍橋詞典the group of nerve fibres (= structures like threads ) that pass signals from the retina at the back of each eye to the brain 視神經（形如細絲的神經纖維束，將視覺信號從眼后部的視網膜傳輸至大腦） 返回 optic nerve