In which direction does the upper eyelid close?

The upper eyelid closes laterally to medially, which reflects the natural motion of the eyelid during blinking. This mechanism involves the orbicularis oculi muscle, which contracts to facilitate the closure of the eyelid. As the eyelid descends, it moves from the outer canthus (the lateral side) toward the inner canthus (the medial side). This movement helps distribute tears across the surface of the eye, providing essential lubrication and supporting overall ocular health.

Understanding the anatomy and physiology of the eyelids is crucial in recognizing the importance of their movement for protecting the eye and maintaining vision. The closing motion contributes to the cycle of tear film stability and maintains a barrier against potential pollutants and pathogens.