Epiphora and lagophthalmos following VII nerve injury is due to

(Refer: AK Khurana Comprehensive Ophthalmology, 6th edition, pg no. 390) *Symptomatic epiphora following facial paralysis is most often associated with one or more of the following: Impairment of eyelid closure A compromised lacrimal pump Lower lid laxity True epiphora is secondary to either an anatomical obstruction of the lacrimal drainage system or functional deficiency like ectropion or lacrimal pump failure. If the punctum is visible without touching the lid, ectropion is diagnosed The main cause for paralytic lagophthalmos is Bell's palsy but it may be secondary to trauma, infections, tumors, and many other conditions. The main purpose when treating lagophthalmos is to prevent exposure keratitis and reestablish eyelid function.