What causes watery eyes during sleep at night?

Generally, tearing of the eyes during sleep at night may be caused by environmental factors, excessive fatigue, conjunctivitis, keratitis, or blepharitis. It is recommended to seek medical attention promptly to determine the underlying cause and receive appropriate treatment. Specific analyses are as follows:

1. Environmental Factors

If the indoor air is dry or dusty while sleeping at night, it may irritate the eyes, leading to tearing, accompanied by mild eye discomfort or a foreign body sensation. It is recommended to use devices such as humidifiers and air purifiers to improve the indoor environment.

2. Excessive Fatigue

Spending prolonged time looking at mobile phones before bedtime can keep the eyes in a state of tension, resulting in the aforementioned symptoms, along with eye fatigue, dryness, pain, and blurred vision. It is advised to avoid prolonged screen exposure and apply warm compresses with a heated towel to the eyes to relieve fatigue.

3. Conjunctivitis

This may be caused by bacterial or viral infections, leading to dilation and congestion of ocular blood vessels. Due to changes in body position when lying down at night, the above symptoms may occur, accompanied by eye pain, itching, and increased secretions. It is recommended to use medications such as chloramphenicol eye drops, ganciclovir eye drops, or ofloxacin eye drops under a doctor's guidance.

4. Keratitis

This is usually caused by infections from bacteria, viruses, or fungi. When lying flat before sleep, poor blood circulation may lead to corneal inflammation and congestion, causing tearing and decreased vision. Treatment may include tobramycin eye drops, levofloxacin eye drops, or acyclovir eye drops as prescribed by a physician.

5. Blepharitis

This may result from local allergic reactions. If exposed to dust mites before sleep, the eyelid margin skin and hair follicles of the eyelashes may become irritated, leading to tearing, redness, and swelling along the eyelid margins. Medications such as doxycycline hydrochloride tablets, metronidazole tablets, or ivermectin tablets may be used under medical supervision.

In daily life, moderate physical exercise—such as running, swimming, jumping rope, or cycling—can help strengthen bodily functions and boost immunity.