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
World Colored Light Heavyweight Championship one day short of a year later, on 8 Mary 1923, when he K.O.-ed Tiger Flowers in the at 2:50 in the first round of a scheduled 12-rounder in Springfield, Ohio. The title then went into abeyance. John Henry Lewis became the first black world light heavyweight champion in 1935. World Colored Light Heavyweight Championship The World Colored Light Heavyweight Championship was a title created in 1921, when African American boxers were prevented from contending for the world light heavyweight title by the color bar. On 30 May 1921, Kid Norfolk fought Lee Anderson for the new colored light heavyweight