Sugar , caffeine , and not getting enough sleep !
you may need to get Hypoallergenic Pillows, if you are using feather pillows you may just be having a slight allergy to them. ....that is what, was happening to me, and it worked great.
Welcome to the MedHelp forum!
Puffiness of one eye is usually due to a localized cause like infection, abrasion of cornea, foreign body in eye, maxillary sinusitis of same side, lacrimal gland infection, infection of hair follicle of the eye lid etc. Both eyes can become puffy in sinusitis, upper respiratory infection, conjunctivitis or due to fluid accumulation due to heart/liver/kidney problem. Please consult an eye specialist. Take care!