Congenital Hypoplastic Trigeminal Nerve Revealed by Manifestation of Corneal Disorders Likely Caused by Neural Factor Deficiency

PURPOSE: To report a case of hypoplastic trigeminal nerve associated with corneal epithelial disorders that were successfully treated with peptides derived from substance P and insulin-like growth factor-1 (IGF-1). CASE REPORT: A 16-month-old boy was referred for treatment of a persistent corneal epithelial defect on his left eye. Magnetic resonance imaging revealed the apparent absence of the trigeminal nerve on the left side, and the patient was therefore diagnosed with neurotrophic keratopathy. Treatment with eye drops containing the tetrapeptides FGLM-NH(2) and SSSR derived from the neuropeptide substance P and the growth factor IGF-1, respectively, resulted in resurfacing of the corneal epithelial defect. DISCUSSION: The trigeminal nerve anomaly of the patient likely gave rise to neurotrophic keratopathy as a result of a deficiency of neural factors, emphasizing the importance of neural regulation in corneal epithelial homeostasis.