If you have a bad sinus congestion from a cold, what typically happens is that both eyes will be watery as a result.
Epiphora is the medical term for excessive watering of the eyes.
When only one eye is watery or tearing (regardless of cause), this is called unilateral epiphora.
The excessive tearing or welling-up in an eye may be from the lacrimal glands (tear ducts) producing too many tears, or … a blockage or congestion in the lacrimal drainage system.
Can a sinus infection cause only one eye to water or tear?
“Yes, this is possible, but only if one tear duct is blocked (which can happen),” says Susan L. Besser, MD, with Mercy Medical Center, Baltimore, and Diplomate American Board of Obesity Medicine and board certified by the American Board of Family Medicine.
If just one eye is excessively watery during a sinus cold, it could be due to that side’s lacrimal drainage structure being naturally more narrower than is the other side’s. This narrowing is more likely as we age.
When a person has a sinus cold, both eyes don’t necessarily become watery. Sometimes neither do, depending on the dynamics of the infection.
An infection or common cold is not the same as allergies. And allergies, of course, are notorious for causing watery eyes.
But in the case of allergies, this is not related to any blockage in the lacrimal drainage system.
Rather, allergies are from irritants (allergens) that the lacrimal glands are responding to by secreting more tears.
However, swelling around the tear ducts can also cause extra secretion, also known as hyperlacrimation.
Unilateral epiphora from sinus congestion may last several days or more, and may come on suddenly and then go away suddenly.
If you’re not sure that one eye is watering more than the other, take this test:
Tilt your head to the side about 45 degrees, in the direction opposite the suspect eye, for 45 seconds. Then straighten and check the inner corner of that eye to see if it has a “lake” of water in it. If it does, it’s tearing more than usual.
You may also want to tilt on the side of the eye to see if any water collects in its outer corner. In the meantime, take good care of your sinus cold with plenty of fluids and be gentle with the nose blowing.