Exposure keratopathy is due to involvement of which cranial nerve: March 2012

Ans: D i.e. 7th cranial nerve Exposure keratopathy is due to any cause which may produce exposure of the cornea due to incomplete closure of the eyelids (lagophthalmos), such as extreme proptosis as in exophthalmic ophthalmoplegia or orbital tumour, paralysis of the orbicularis (neuroparalytic keratopathy etc.) Keratopathy Neurotrophic keratopathy (desquamation of corneal epithelium) occurs in some cases in which trigeminal nerve is paralyzed Neuroparalytic keratopathy is seen in facial nerve palsy as occurs in Bell's palsy, leprosy or neurological disorders leading to ectropion, lagophthalmos & exposure keratopathy