A ring of smooth muscle fibers located close to the pupillary margin, a little anterior to the iris’ epithelium. It encircles the pupil and constricts the pupil in bright light during accommodation or pupillary light reflex.
Also Known As
- Iris Sphincter Muscle
- Pupillary Sphincter
- Pupillary Constrictor
- Circular Muscle of Iris
- Circular Fibers