Direct Versus Indirect Corneal Neurotization for the Treatment of Neurotrophic Keratopathy: A Multicenter Prospective Comparative Study

Purpose: To analyze the comparative safety and efficacy of two techniques of corneal neurotization (CN) (direct corneal neurotization [DCN] vs indirect corneal neurotization [ICN]) for the treatment of neurotrophic keratopathy (NK). Design: Multicenter interventional prospective comparative case series. Methods: This study took place at ASST Santi Paolo e Carlo University Hospital, Milan; S.Orsola-Malpighi University Hospital, Bologna; and Santa Maria alle Scotte University Hospital, Siena, Italy. The study population consisted of consecutive patients with NK who underwent CN between November 2014 and October 2019. The intervention procedures included DCN, which was was performed by transferring contralateral supraorbital and supratrochlear nerves. ICN was performed using a sural nerve graft. The main outcome measures included NK healing, corneal sensitivity, corneal nerve fiber length (CNFL) measured by in vivo confocal microscopy (IVCM), and complication rates. Results: A total of 26 eyes in 25 patients were included: 16 eyes were treated with DCN and 10 with ICN. After surgery, NK was healed in all patients after a mean period of 3.9 months without differences between DCN and ICN. Mean corneal sensitivity improved significantly 1 year after surgery (from 3.07 to 22.11 mm; P < .001) without differences between the 2 groups. The corneal sub-basal nerve plexus that was absent before surgery in all patients, except 4, become detectable in all cases (mean CNFL: 14.67 ± 7.92 mm/mm2 1 year postoperatively). No major complications were recorded in both groups. Conclusions: CN allowed the healing of NK in all patients as well as improvement of corneal sensitivity in most of them thanks to nerve regeneration documented by IVCM. One year postoperatively, DCN and ICN showed comparable outcomes.