Ophthalmology Diseases of orbit, Lids and lacrimal apparatus 622d84d9 Most common cause of ptosis - A Myasthenia gravis B Paralysis of 3rd nerve C Idiopathic D Congenital High-Yield Explanation Congenital weakness of the levator palpebrae superioris innervated by third cranial nerve III occulomotor . Ref: Ak khurana 6th edition page no:378