Inclusion criteria included:  • Eyes with established diagnosis of NK in stages 2 or 3 refractory to standard treatment* that underwent topical insulin treatment.  The diagnosis of NK was based on the following criteria:  Decreased or absence of corneal sensation; AND Corneal injury [PED and/or corneal ulcer] refractory to standard treatment*; AND  Clinical history of conditions related to trigeminal innervation impairment;  Standard treatment - lubrication with artificial tears, topical and/or oral antibiotics, topical and/or oral steroids, antiviral drugs, punctal plugs, therapeutic CL, amniotic membrane surgery and temporary tarsorrhaphy.´  We excluded every patient with corneal ulcer and signs of infection.