Our eyes instinctively close when we sneeze. This consistent closure suggests a coordinated biological response rather than a mere coincidence. This article explores the scientific reasons behind this automatic reaction and addresses the possibility of overriding it.
The Sneeze Reflex
A sneeze, also known as sternutation, is a powerful and rapid expulsion of air from the lungs through the nose and mouth. This involuntary reflex serves a crucial purpose: to clear irritants from the nasal passages. When foreign particles irritate the sensitive lining of the nose, sensory nerves are stimulated, sending signals to the brainstem. The brainstem then orchestrates a complex sequence of muscle contractions throughout the body, culminating in the forceful release of air. This coordinated action involves a deep intake of breath followed by a buildup of pressure, and then a sudden exhalation that can reach speeds of approximately 10 miles per hour.
Why Your Eyes Close
Eye closure during a sneeze is a protective mechanism coordinated by the nervous system. When irritants trigger the sneeze reflex, signals travel along the trigeminal nerve, a major cranial nerve responsible for facial sensation and motor functions. These signals reach the brainstem’s sneeze center, which then sends commands to muscles, including those controlling the eyelids. This reflex shields the eyes from the high pressure generated during a sneeze, which can range from approximately 2,185 to 5,685 Pascals (Pa) along the skull base.
Beyond pressure protection, eye closure also prevents expelled particles from entering the eyes. A sneeze can eject thousands of tiny droplets containing mucus, irritants, and pathogens at high velocity. Automatically shutting the eyelids creates a barrier, preventing these airborne particles from contaminating the delicate eye surface. This coordinated response safeguards the eyes from potential irritation or infection.
Can You Consciously Override It?
While the eye-closing reflex during a sneeze is automatic, it is technically possible for some individuals to consciously override it. However, doing so requires a concerted effort to counteract the body’s natural, involuntary response. The reflex is so deeply ingrained that most people find it incredibly difficult, if not impossible, to keep their eyes open without physical assistance.
Attempting to keep your eyes open during a sneeze is generally not advised, as it bypasses a natural protective mechanism. Primary concerns include discomfort and potential irritation from the forceful expulsion of air and particles directly into the eyes. Although the popular myth of eyeballs popping out from pressure is unfounded, as pressure builds in blood vessels and not directly in the eyes, allowing the reflex to occur naturally ensures the eyes are protected from expelled material.