Swollen eyes after waking up may be related to drinking a lot of water before going to bed, blepharitis, allergic dermatitis and other reasons. 1. Drinking a lot of water before going to bed: If you drink a lot of water before going to bed, it may lead to the accumulation of water in the body, and it is easy to wake up with swollen eyes. 2. Blepharitis: If the blepharoplasts are inflamed locally due to poor makeup removal, etc., redness, swelling and pain in the eyes may occur after waking up. 3. Allergic dermatitis: If you come into contact with allergenic substances such as dust mites during sleep, it can cause abnormal immunity in the body and cause redness and swelling of the eyes. If the person who wakes up with swollen eyes has other uncomfortable symptoms, he should go to the hospital in time, clarify the cause of the disease, and carry out standardized treatment under the guidance of the doctor.