Its muscles control the pupil (4)
I believe the answer is:
iris
(Other definitions for iris that I've seen before include "may open up in camera" , "Flower - rainbow" , "Pupil's place?" , "Female" , "Eye part or attractive flower" .)
I believe the answer is:
iris
(Other definitions for iris that I've seen before include "may open up in camera" , "Flower - rainbow" , "Pupil's place?" , "Female" , "Eye part or attractive flower" .)