Acquired disorder of unknown origin, manifested by an easily everted floppy upper eyelid and papillary conjunctivitis of the upper palpebral conjunctiva. It is primarily associated with obese men and obstructive sleep apnoea. The tarsus of the upper eyelid becomes softer and looser probably due to mechanical forces and enzymatical changes. The upper eyelid everts during sleep, resulting in irritation, papillary conjunctivitis, and conjunctival keratinization. Effective treatment consists of preventing the upper eyelid from everting while the patient is sleeping.