What can cause me to wake up with my eye swollen?

See eye doctor: Would need to see it. May be allergies. Try over the counter allergy meds. Try shower and wash hair before bed so allergans don't get on pillow and on eyes. Use dilute baby shampoo to lightly wash eye lids before bed.

It DEpends: The most common cause is sleeping with your head flat on the mattress, without using a pillow. If slight elevation doesn't improve the situation your physician should be consulted.

Many reasons: They could be swollen for many different such as fluid overload, position, allergies, metabolic disorder etc. You might check with your physician.