Swollen eyelids in the morning are usually caused by the following reasons: 1. Eyelid edema due to allergic blepharitis is usually caused by an allergic reaction of the eye skin to the lint, skin dander, mites, etc. of bedding. It is also accompanied by local skin reddening and itching. 2. edema caused by prolonged lateral or prone sleep, resulting in pressure on the eyelid tissue and obstruction of lymphatic fluid or venous blood flow in the subcutaneous tissue. edema can disappear naturally if attention is paid to improving lifestyle habits, maintaining a flat sleep, and padding pillows. 3. edema caused by right heart failure, resulting in obstruction of venous return from the body circulation. 4. Due to kidney insufficiency caused by diseases such as nephritis, a large amount of water and inorganic salts in the body cannot be metabolized and accumulate in the subcutaneous tissues, causing edema of the eyelids.