I will tell you that it is not very strange that your eyes swell when you go to sleep. Swelling eyes during sleep is a common phenomenon that will not last for a long time. The cause of your swelling eyes during sleep is definitely not single. Fluid retention is the most possible cause of swelling eyes. When you sleep, the fluid in the body tends to accumulate around eyes, which gives eyes a swollen and swelling appearance. When you consume too much alcohol and salty food your eyes will swell either. And if you cry you will get swelling eyes when you are sleeping. Dehydration will likewise lead to accumulation of fluid in the body, as well as around the eyes, causing swelling eyes. Other possible causes include aging, allergies, high blood pressure and lack of sleep. It seems that causes for swelling eyes are so many and now it is your time to find out the exact one.
It is not normal. Your swelling eyes may be caused by the eyes infection. You need to have the exact check on the eye. You could use the eyes drops to make the eyes get rid of the invisible bacterium firstly. Then you could use the warm compress to make the eyes feel comfortable and get moisture.