Blowing air out of your eyes sounds like a cartoon phenomenon, yet it is a documented, though uncommon, human ability. This action is possible due to subtle anatomical connections linking the eye and the nose. This article explores the biological pathways and mechanisms behind this unusual ability.
The Anatomical Link Between Eye and Nose
The lacrimal system normally drains tears from the eye’s surface into the nasal cavity, which is why crying often causes a runny nose. Tears enter the system through two tiny openings, called the puncta, located on the inner edge of the eyelids. These openings lead into small tubes known as the canaliculi.
The canaliculi empty into the lacrimal sac, a small reservoir near the nose. From the sac, fluid travels downward through the nasolacrimal duct (NLD), a bony canal that ultimately opens into the nasal cavity. The entire system acts as a downward-flowing drain.
The system is designed to prevent backward flow. The Valve of Hasner, located where the NLD opens into the nose, acts as a check valve to prevent air or mucus from traveling up the duct. The Valve of Rosenmüller, located where the canaliculi enter the lacrimal sac, also helps prevent the reflux of fluid and air back toward the eye’s surface.
The Phenomenon of Air Reversal
The ability to blow air out of the eyes results from a structural variation in the lacrimal system, requiring a patent pathway that allows air pressure to reverse the normal flow. The mechanism is triggered by forcefully increasing pressure in the nasal cavity, often by pinching the nostrils shut and attempting to blow out (similar to the Valsalva maneuver).
When this pressure is generated, the air is forced against the walls of the nasolacrimal duct. If the Valve of Hasner is absent or significantly incompetent (weak), the air bypasses this normal barrier and travels up the NLD into the lacrimal sac. From the sac, the air then travels through the canaliculi and finally exits the body through the puncta in the eyelids.
This ability indicates that the person has a natural variation, often a patent or functionally deficient valve system. The air reversal can be observed as a bubbling or squirt of air exiting through the small punctal openings. While the phenomenon is striking, it simply means the one-way valve system designed to keep the drainage unidirectional is not fully functional for that individual.
Medical Context and Safety
The presence of a patent nasolacrimal duct allowing air to flow backward is generally not considered a major health concern. However, it represents a pathway where air-borne irritants or bacteria from the nasal cavity can travel into the lacrimal system. This retrograde flow can increase the risk of infection in the lacrimal sac.
One related condition is dacryocystitis, which is an inflammation or infection of the lacrimal sac, often caused by the stagnation of tears when the duct is obstructed. While the ability to blow air through suggests a patent duct, a weakened valve system can still allow infectious material to enter.
Individuals who can perform this action should avoid forcing air through their eyes excessively, especially when they have a cold or sinus infection, to minimize the risk of introducing pathogens. If the act causes pain or if there are signs of chronic discharge or swelling near the inner corner of the eye, a medical evaluation is warranted. For those without symptoms, this ability is typically a harmless, unusual anatomical variation.