musculus sphincter pupillae

The sphincter pupillae muscle is one of the internal eye muscles and is responsible for constricting the pupil. This so-called miosis takes place reflexively when light enters the eye and is also part of the near vision tria. The sphincter pupillae muscle can be artificially stimulated to contract using substances such as miotics. What is … Musculus Sphincter Pupillae: Structure, Function & Diseases