Isaac Hays (1796 – 1879) was an American ophthalmologist, medical ethicist, and naturalist. A founding member of the American Medical Association, and the first president of the Philadelphia Ophthalmological Society, Hays published the first study of non-congential colorblindness and the first case of astigmatism in America. He was editor or co-editor of The American Journal of the Medical Sciences for over 50 years.