Redness of the eyes at night, which clears up during the day after medication, may be due to incomplete eyelid closure, allergic conjunctivitis and other causes. Patients with incomplete eyelid closure who sleep at night, the eyelids can not be completely closed, leaving a gap, easily exposed to the external environment of the cornea and conjunctival tissues to dry, causing irritation and congestion, so the patient may appear red eyes. During the day, patients use sodium vitrate eye drops to moisten the eye surface, and the eyeball moves normally, and the patient’s eye congestion can be relieved. Allergic conjunctivitis patients who are allergic to bedding attached to the cotton wool, skin debris, mites, etc., when sleeping due to contact with the above allergens can trigger an allergic reaction, resulting in patients with eye congestion, wake up and use anti-allergy eye drops, such as sodium cromoglycate eye drops, and no longer contact with bedding during the daytime normal activities, the allergy symptoms will disappear, the congestion of the eyes can be relieved. It is recommended that patients with obvious eye congestion consult a hospital in a timely manner to assess their condition and follow the doctor’s instructions for treatment.