Ptosis and Convergence Insufficiency, which one may develop from the other?

It is unlikely that one is related to the other. The eyelid muscle is innervated by the upper division of the third cranial nerve. Congenital ptosis is related to embryological malformation of the levator muscle. The etiology of convergence insufficiency is unknown.

While the two conditions may occur together, they are not directly related and/or causative. Congenital ptosis is usually related to maldevelopment of the levator muscle.