A function of the orbicularis oculi muscle is to:

The orbicularis oculi muscle is a circular muscle that surrounds the eye. Its primary function is to enable the closing of the eyelids, which serves various purposes such as protecting the eyes from irritants, facilitating blinking to keep the eyes moist, and contributing to facial expressions such as squinting or winking.

Understanding the functions of facial muscles helps highlight why the orbicularis oculi is specifically designed for closing the eye. The elaborate structure and positioning of this muscle allow it to effectively contract and draw the eyelids together, showcasing its role in eye protection and expression. Other functions of facial muscles, such as raising the eyebrows or closing the mouth, involve different muscle groups that are structured specifically for those movements.