The experience of “water” coming out of your eye when you blow your nose is a common physiological event revealing a direct connection between your tear drainage system and your nasal cavity. This phenomenon is not a sign of a problem, but rather a demonstration of how the body’s plumbing system can sometimes reverse its normal flow under pressure. Blowing your nose temporarily alters the pressure dynamics in your head, causing fluid to seek the path of least resistance, which leads back out through the eye.
The Connection Between the Nose and Eye
Tears are continuously produced by the lacrimal glands, situated above the outer corner of each eye, to lubricate the surface and wash away foreign particles. These tears drain through a specialized system starting with two tiny openings called puncta, located at the inner corner of the upper and lower eyelids.
The puncta lead into small canals, which merge into the lacrimal sac, located on the side of the nose. From the lacrimal sac, a single tube descends: the nasolacrimal duct. This duct runs downward through a bony canal and opens directly into the nasal cavity. This system serves as a direct drainage pathway, explaining why tears often cause a runny nose when a person cries or experiences an allergy.
How Pressure Forces Tears Out
Forcefully blowing your nose involves closing your mouth and tightening the muscles around your nasal cavity, causing a rapid increase in internal air pressure. Normally, tears flow downward through the nasolacrimal duct and into the nose. However, the sudden spike in pressure from the nasal side can overcome this normal flow.
This increased pressure forces air, mucus, and collected tear fluid backward up through the nasolacrimal duct. Since the fluid cannot escape back into the lacrimal sac, it is pushed out through the puncta, the tiny openings in the inner corner of the eyelids. This fluid, which is primarily tear fluid, exits the eye when you blow. High pressure can temporarily overwhelm small structures intended to prevent reflux, especially in individuals with a wider duct anatomy.
Knowing When to See a Doctor
While the reverse flow of tears when blowing your nose is a normal anatomical quirk, persistent eye watering or other symptoms may indicate an underlying drainage issue. A blocked tear duct, known as dacryostenosis, prevents tears from draining properly, leading to a continuous watery eye. Blockages can be caused by infection, inflammation, age-related narrowing of the ducts, or facial injury.
You should seek medical advice if you experience symptoms beyond the temporary overflow when blowing your nose. These signs suggest a complete or partial obstruction that needs professional evaluation and potential treatment. Warning signs include:
- Painful swelling or redness near the inner corner of the eye, which may signal an infection of the lacrimal sac.
- Recurrent eye infections.
- A sticky white or yellow discharge.
- Crusting of the eyelids.