Orbicularis Oculi Muscle: Function & Location - Muscle Health

The orbicularis oculi muscle is the muscle that is responsible for blinking and squinting. This thin, sphincter-like muscle encircles the eye socket, and when it contracts, it causes the eyelids to close. The orbicularis oculi is also responsible for controlling the degree to which the eyelids are open, allowing individuals to squint or partially close the eyes.