Iris sphincter muscle Iris sphincter muscle The iris sphincter muscle (pupillary sphincter, pupillary constrictor, circular muscle of iris, circular fibers) is a muscle in the part of the eye called the iris. It encircles the pupil of the iris, appropriate to its function as a constrictor of the pupil. It is found in vertebrates and some cephalopods. Initially, all the myocytes are of the smooth muscle type but, later in life, most cells are of the striated muscle type. Its dimensions are about 0.75 mm wide by 0.15 mm thick. In humans, it functions to constrict the pupil in bright light (pupillary light
The Light That Failed The Light That Failed The Light That Failed is a novel by the Nobel Prize-winning English author Rudyard Kipling that was first published in "Lippincott's Monthly Magazine" dated January 1891. Most of the novel is set in London, but many important events throughout the story occur in Sudan and Port Said. It follows the life of Dick Heldar, an artist and painter who goes blind, and his unrequited love for his childhood playmate, Maisie. It is Kipling's first novel, written when he was 26 years old, and is semi-autobiographical; being based upon his own unrequited love for Florence Garrard. Though