I’m trying to remember a movie that was circus based where I think animals were turned into people.
They couldn’t leave as they would die. The ringmaster did it with magic eye things(?)
You might be thinking of We're Back! A Dinosaur's Story. There are some time-traveling dinosaurs who manage to befriend a pair of children. These children, a boy and a girl, fall into the clutches of one Dr. Screweyes, who runs a creepy circus, and turns them into chimpanzees (y'know, for evil!).
It might be the movie Animal Crackers (2017)
It takes place at a circus and some of the performers are humans transformed to animals. They can leave the circus, but they need to eat a human biscuit from the box that transformed them or they remain animals forever. The magic is not performed with a magic eye but with magic animal-shaped biscuits. Otherwise it seems to be a match.