Irisby BGOctober 29, 2019Location: Anterior eye; separates the anterior and posterior chambers. Function: Contracts or dilates to change the size of the pupil. This allows for more/less light to enter the eye. Structure: Colored (usually brown, green or blue) muscle in the anterior eye. Related « Back to Glossary Index Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment Name * Email * Website Save my name, email, and website in this browser for the next time I comment.