It is normal for tears to well up or even stream down your face during a large yawn. This physiological response is known as reflex tearing, and it is not an emotional reaction but a purely mechanical one. The phenomenon occurs when the intense muscular movements associated with a yawn temporarily affect the apparatus responsible for tear production and drainage.
The Mechanical Cause of Yawn Tears
The act of yawning is an involuntary reflex that involves a wide stretch of the jaw and an intense contraction of numerous facial muscles. This muscular activity is the primary trigger for the tears that appear during a yawn. Specifically, the orbicularis oculi muscles, which encircle the eye sockets and control blinking, contract tightly as the eyes instinctively squeeze shut.
This intense tightening squeezes the lacrimal glands, which are the main structures responsible for producing the aqueous layer of tears. The lacrimal glands are located in the upper, outer corner of the eye orbit. The pressure exerted by the surrounding muscles forces the tears that are already produced and stored within the gland out onto the surface of the eye.
Furthermore, the wide opening of the jaw and the stretching of the facial tissues increase the overall pressure within the orbital region. This pressure contributes to the immediate overflow of tears, pushing the built-up fluid out faster than the eye’s drainage system can handle.
How the Lacrimal Drainage System Works
Tears are constantly produced to keep the eyes lubricated. A sophisticated system is designed to drain this fluid away into the nasal cavity.
The process begins at the puncta, which are two tiny openings located on the inner corner of the upper and lower eyelids. From the puncta, tears flow into small channels called the canaliculi, which lead to the lacrimal sac nestled beside the nose. The final segment of the drainage pathway is the nasolacrimal duct, often referred to as the tear duct, which carries the fluid down through a bony channel and into the back of the nose.
During the powerful muscle contractions of a yawn, this drainage system is temporarily compromised. The tightening of the facial muscles, particularly those around the eye, can briefly constrict or block the small openings of the puncta or the canaliculi.
When Excessive Tearing Requires Attention
If tears only appear when you yawn, it is a normal physiological event and does not require medical attention. However, persistent or chronic excessive tearing, known medically as epiphora, that occurs independently of yawning may signal an underlying issue. This constant watering can be a symptom of conditions that either cause overproduction of tears or result in inadequate drainage.
Conditions such as blocked tear ducts, caused by inflammation, infection, or age-related narrowing, prevent tears from draining properly. Other potential causes include dry eye syndrome, where the eye produces too many watery tears in reaction to irritation, or eyelid problems like an inward or outward turning eyelid.
If excessive tearing is accompanied by pain, redness, blurry vision, or a discharge, it is advisable to consult an eye care professional.