NGF and keratitis: On the ocular surface, NGF has been studied in the context of allergic conjunctivitis [2,3,4,5], NK [6,7,8,9,10,11,12], immune and infectious keratitis [13,14,15,16], DED [17,18,19], corneal transplant [20,21], cataract [22], and refractive surgery [23,24,25].