Corneal Neurotization for Neurotrophic Keratopathy: Clinical Outcomes and In Vivo Confocal Microscopic and Histopathological Findings.

PURPOSE: To describe the long-term outcomes and in vivo confocal microscopic (IVCM) and histopathological findings after corneal neurotization surgery.
METHODS: We included 2 patients who underwent corneal neurotization surgery for severe unilateral neurotrophic keratopathy secondary to cerebellopontine angle meningioma. Corneal sensation was measured using the Cochet-Bonnet esthesiometer (CBE) (0-60 mm). IVCM was performed using the Heidelberg HRT3 Rostock Corneal Module. Histopathological examination was performed on the excised corneoscleral disc of patient 2.
RESULTS: In patient 1, corneal sensation improved from 0 mm preoperatively to 60 mm in all 4 quadrants by 2 years postoperatively and was maintained at 5 years postoperatively with identifiable subbasal and stromal corneal nerves on IVCM. In patient 2, corneal sensation improved from 0 mm preoperatively to 10 mm in 3 quadrants (9 months postoperatively) but returned to 0 mm in all quadrants by 2 years postoperatively. IVCM failed to identify any subbasal and stromal corneal nerves. At 5 years postoperatively, evisceration was performed to ameliorate uncontrolled and persistent ocular pain and poor cosmesis. Histopathological examination of the excised corneoscleral disc confirmed the presence of normal-sized, central corneal stromal nerve fascicles but without direct continuity with the transplanted perilimbal nerve bundles.
CONCLUSIONS: Our study elucidates the mechanism of corneal neurotization surgery at a cellular level. Although only 1 patient achieved long-term improvement in corneal sensation postoperatively, the findings on IVCM and histopathological examination suggest that partial regeneration/maintenance of corneal nerves after corneal neurotization surgery is likely attributed to the paracrine neurotrophic support, instead of direct sprouting, from the perilimbal transplanted nerve fascicles.