Enlarged corneal nerves may be seen in all of the following except –
Enlarged corneal nerves 
Enlarged corneal nerves appear in several conditions; the most important to recognize is the dominantly inherited multiple endocrine neoplasia syndrome type 2B (MEN type 2B).
Other causes of enlarged corneal nerves include :-

Keratoconus
Advanced age
Neurofibromatosis
Keratoconjunctivitis sicca
Leprosy
Fuchs' endothelial dystrophy
Ichthyosis
Congenital glaucoma
Refsum's disease
Acanthamoeba keratitis
Trauma
Failed corneal graft
Hereditary ectodermal dysplasia
Keratoconus
Herpes simplex keratitis
Leprosy
Neurofibromatosis