Restoring Corneal Sensation: Corneal Neurotization Surgery

Contributed by Dr. Ilya Leyngold, Duke University

 

Corneal neurotization surgery is a procedure performed to treat corneal anesthesia (numbness of the transparent front part of the eye covering the pupil and iris). Corneal anesthesia may result in a debilitating and visually threatening condition called neurotrophic keratopathy (NK), where affected individuals may develop corneal ulcerations, infections, and are at risk of losing vision. Corneal anesthesia may result from multiple causes. Most common culprits include certain viral infections (i.e. herpetic eye infections), and brain tumors or surgery. It may also arise as a result of head trauma, complication of eye surgery, contact lens overuse, certain eye drops, or congenital defects.

Until recently no curative treatment existed for NK and many patients required multiple medical and surgical interventions to prevent further deterioration of the cornea. In the past many patients with this condition had to have their eye closed completely to prevent perforation of the cornea (developing a hole in the cornea). In 2009, the first scientific peer- reviewed article came out describing a case series of patients who underwent corneal neurotization. In this paper, the authors described a novel technique in which healthy donor nerves were “borrowed” from the other side of the face and transferred (i.e. “grafted”) to the affected eye. Although this procedure resulted in successful restoration of corneal sensation, improvement in vision and health of the cornea, it was quite invasive, requiring a large incision in the scalp, tedious dissection, and prolonged general anesthesia.

Less invasive corneal neurotization techniques are now available to achieve successful restoration of corneal sensation and improve vision. One of the techniques involves using a cadaveric nerve graft attached to a small stump of the healthy donor nerve isolated through a small lower or upper eyelid incision. Another uses a small telescope (endoscope) to dissect the donor nerve and transfer it to the affected eye. Regardless of the particular technique used, it takes several months for the nerves to grow into the cornea and restore its sensation and healing capacity. During this time, the eye may need to be protected in selected patients by closing the lids with a suture.

The swelling and bruising around the eye(s) from the surgery takes approximately 2-3 weeks to resolve. The eyelids of the affected eye maybe temporarily sutured together to prevent corneal problems during the healing phase. The numbness in the skin area from which the donor nerve is harvested may take several weeks to several months to improve, but generally returns to normal in most patients.

 

Reference: Leyngold, Yen, Tian, Leyngold, Vora and Weller. Minimally Invasive Corneal Neurotization with Acellular Nerve Allograft: Surgical Technique and Clinical Outcomes. Ophthal Plast Reconstr Surg., 2018 (e-print ahead of publication).