Hi greetings from the UK. Yes it's pretty obvious your right eye does look bigger than YOUR left. Common causes include:- right eyeball globe in normal position but right upper eyelid more pulled upwards (right upper lid retraction). Common causes include thyroid eye disease, right upper lid retraction due to bilateral overreaction from a drooping left upper lid (left upper eyelid) ptosisLess common causes include the right eyeball globe being pushed forward - right proptosis e.g. from thyroid eye disease and other orbital problemsRight eyeball actually being in correct position but left eye looking smaller due to it sinking back into the socket (left enophthalmos) e.g. due to old forgotten left orbital trauma causing a blowout fracture. Really uncommon causes which are usually longstanding include pseudoproptosis due to the right eye being bigger from pathology which is usually pretty obvious (high myopia, congenital glaucoma) or the pseudoenophthalmos from the left eye being smaller (e.g. congenital microphthalmos). Common things being common, it's most likely due to upper lid retraction due to ptosis in the other eyelid- but you would need a comprehensive orbital examination and ocular exam to rule out other more sinister causes. See a good oculoplastic consultant (e.g. via ASOPRS website) or at least a general ophthalmologist who'll be able to rule out proptosis by measuring your exophthalmometry readings. They may recommend orbital CT scanning should they find any suggestion of proptosis. Good luck and best wishes.David