Although it is not the same size for the both eyes, it is still not normal for you to get the one eye open bigger than the other. There may be the eyes infection for you. You could go to the hospital to have a check on the eyes. You may accept the treatment as soon as possible.
Sometimes we do find our eyes not identical to each other. As far as I know, this might be resulted from the way you sleep, which might affect your eyes. Also, your problem might be droopy eyes, which might be derived from some neurological problems, which needs to be examined in the hospital. If the problem does not go away as time goes by, you really need to see a doctor.
Hello, actually according to some research, everyone has one eye that is bigger than the other. The only difference is that sometimes it is more noticeable when the eyes are tired or strained. But in some situations, some eye problems can also cause your situation if you feel some other discomfort about your eyes, so to make sure, you can go to see the doctor and have a thorough checking.