NEW YORK — Surgeons in New York say they have performed the world's first complete eye transplant on a man, although it is not certain he will regain vision.

Aaron James, who survived a high-voltage electrical accident, underwent 21 hours of surgery that replaced half of his face.

Surgeons have been able to transplant corneas successfully for years.

Experts have called the breakthrough a pivotal moment in the quest to restore sight to millions of people.

James, a high-voltage utility line worker from Arkansas, lost most of his face when it accidentally touched a 7,200-volt live wire in 2021.

On 27 May this year, he underwent a rare partial face transplant in addition to the eye transplant — which involved more than 140 healthcare professionals.

Surgeons at NYU Langone Health, who performed the complicated surgery, said on Thursday that James, 46, was recovering well from the dual transplant and the donated eye looked remarkably healthy. His right eye still works.

"The mere fact that we've accomplished the first successful whole-eye transplant with a face is a tremendous feat many have long thought was not possible," said Dr Eduardo Rodriguez, one of the leading surgeons on the team. "We've made one major step forward and have paved the way for the next chapter to restore vision."

Doctors say James' surgery offers scientists an unprecedented window into how the human eye tries to heal.

"We're not claiming that we are going to restore sight," Dr Rodriguez told ABC News. "But there's no doubt in my mind we are one step closer."

Doctors said there was direct blood flow to the retina — the part of the eye that sends images to the brain. While there is no certainty James will regain vision in his new eye, doctors do not rule out the possibility either.

"If I can see out of it, that's great," James said in an interview. "But if it'll kick-start the next path in the medical field, then I'm all for it."

James, a military veteran, will continue to be monitored by doctors, but the progress they have seen with the eye is "exceptional" says Bruce E. Gelb, MD, a transplant surgeon at New York University.

The donated face and eye came from a single male donor in his 30s. During the surgery, doctors injected adult stem cells from the donor's bone marrow into the optic nerve to encourage its repair.

James is only the 19th person in the US to undergo a face transplant.

His wife of 20 years, Meagan James, told CNN seeing him after the surgery "was a crazy, great, weird, strange, ecstatic, happy feeling".

"I was just happy he made it through, and everything was good in the moment."

After the accident, James had to have his left eye removed because of the pain and has undergone numerous surgeries, including one for a prosthetic arm.

He has called the eye transplant "life changing" and says he is "grateful beyond words" to the donor and their family for making the surgery possible.

"I just look like a normal person walking down the street," he told NBC News. — BBC