Watery Eye (One Eye): Possible Causes and Warning Signs

A watery eye (one eye) — people of all ages come to doctors with this complaint. Tears are constantly produced by the lacrimal glands, located just above the eyes, and drain through a small opening in the corner of the eye called the tear duct. When there are too many tears or the drainage is impaired, the eye starts to water.

Why one eye waters: how tears are produced and drained

Tears keep the surface of the eye moist and wash away particles and foreign objects. Normally they leave the eye through the tear duct — a narrow tube leading into the nasal cavity. If the duct is blocked, tears are retained and flow outward. Another mechanism: the eye becomes dry and uncomfortable, and the body responds by producing too many tears. Dry eye is in fact named as one of the most common causes of excessive tearing.

Common causes of tearing from one eye

Tearing can be a normal reaction to smoke, wind, or cold. It can be caused by a speck, eyelash, or grain of sand getting into the eye. Other causes include a blocked tear duct, allergy, or infection, such as conjunctivitis — inflammation of the surface of the eye. Eyes also water with eyelid problems: when the eyelid pulls away from the eye or, conversely, turns inward. In some people, tearing is associated with taking certain medications and with cancer treatment. In infants, the tear ducts are sometimes not yet fully developed, and this usually resolves by a few weeks of life.

When the eye hurts and waters: what this may indicate

Pain together with tearing is a reason not to delay a visit. This happens with a foreign body, a scratch on the eye, inflammation, or infection. Redness and copious discharge from the eye also suggest possible inflammation. If the left eye or the right eye hurts and waters, this sign alone does not determine the cause — the doctor simply clarifies the side during the examination.

Why the eye waters all the time

When one eye waters constantly, it interferes with reading, working, and going outside. Prolonged, unexplained tearing is on the list of reasons to see a doctor. The cause may be a blocked tear duct, eyelid changes, or chronic irritation. Finding out why the eye waters all the time is only possible during an examination.

How a doctor determines the cause of tearing

The doctor examines the eyes and asks about the symptoms: when the tearing started, how often it recurs, whether one eye or both are affected, whether there are vision problems, pain, or nasal congestion. They clarify what medications the person takes, whether there is an allergy, and whether there has been an eye injury. One of the main checks for excessive tearing is assessing whether the eyes are too dry. If necessary, the doctor orders tests and refers the patient to an ophthalmologist — an eye specialist.

When to see an ophthalmologist urgently

You should book an appointment if your eyes water so much that it interferes with everyday activities, if the eyelid turns inward or pulls away from the eye, if lumps or swelling appear around the eyes that do not resolve after home care. You should seek help immediately for changes in vision, such as vision loss, and for severe eye pain.

• Changes in vision, including vision loss.
• Severe eye pain.
• Chemicals getting into the eye.
• Severe eye injury, bleeding.
• Prolonged tearing without a clear cause.

Tearing by itself is rarely an emergency and is not a reason to call an ambulance. You should call 103 or 112 if chemicals have gotten into the eye, if severe pain, bleeding, or loss of vision has occurred, and also in case of severe eye injury.

This material is for reference: it helps to understand what tearing from one eye may indicate, but it does not replace a doctor's examination, and the decision about testing is made only by a specialist.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer