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
Herpes simplex keratitis