What is another word for pupillary sphincter?
Pronunciation: [pjˈuːpɪləɹi sfˈɪŋktə] (IPA) 
The pupillary sphincter is a small, circular muscle found in the iris of the eye that regulates the size of the pupil. In medical terms, it is often referred to as the iris sphincter or pupillary constrictor. Additionally, it may also be called the intra-pupillary muscle or simply the iris muscle. Synonyms for this important eye muscle can vary depending on the context, but they all refer to the same structure responsible for controlling the amount of light that enters the eye. Whether diagnosed with pupillary sphincter dysfunction or merely discussing the anatomy of the eye, these alternative terms may be useful to know.
