Canadian doctors pioneer new technique that restores sensation to eye

WATCH ABOVE: SickKids surgeons pioneer new surgery that restores lost feeling in eye. Carey Marsden reports. 

Abby Messner tried injections to her eye, wearing specialized hard contact lenses, surgeries to remove scarring and even stitching part of her eye closed.

Years ago, the 18-year-old lost feeling in her left eye – a condition called corneal anaesthesia after she had a brain tumour removed.

She couldn’t feel pain, and couldn’t tell when her eye was injured or infected. Ultimately, the teenager had to quit sports, limit her time outdoors and cut back on other activities with her friends.

But with the help of Canadian doctors who have put together a novel treatment, she’s had the sensation in her left eye returned. She’s even eligible for a cornea transplant now.

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She’s the first of many patients the hospital hopes to treat.

“I’ve gained full feeling back into my eye and I’ve gained a bit in my cheek, because they put more nerves into my face too, so I’ve gained some in my face,” Messner told Global News.

Canadian scientists out of the Hospital for Sick Children say they’ve pioneered an innovative surgery that restores feeling in the eye by transplanting nerve grafts from a patient’s own leg. The novel technique is called corneal neurotisation – the doctors say it’s a new approach to a problem that didn’t have a solution before.

“We’ve known for a while that we can transplant nerves to regenerate, to provide movement and also sensation from other work that we do. This is a relatively new application that we’ve learned from studies elsewhere that it is possible to get new sensory information into the eye,” according to Dr. Greg Borschel, a plastic and reconstructive surgeon, at SickKids Hospital.

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With the procedure, patients can gain enough feeling in their eye to let them know if sand or a minute piece of grit gets in. Some patients without feeling risk having dust roll around in the eye, causing scarring, laceration and, with time, loss of vision could occur.

“This provides them with a new way to protect the eye that was ultimately not available before,” Borschel explained.

So far, the hospital has treated eight patients – and a total of 10 eyes –  who have had the sensation in their eyes restored.

Before this technique, doctors reported on another procedure in medical literature but it wasn’t widely adopted and rarely used. It was invasive: an incision from ear to ear on the scalp, then surgeons pulled down the skin from the patient’s forehead.

“The problem is that with this old method of doing it, it just wasn’t practical. It was very daunting and no eye doctors or plastic surgeons, such as myself were willing to take it on,” Borschel said to Global News.

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This time around, the treatment relies on taking a part of the nerve from the leg and transplanting it above the eye on the side of the patient’s face that still has feeling. The nerve graft from the leg is like a spare part – the nerve will regenerate.

According to doctors, the nerve graft is tunneled under the skin, across the forehead and to the damaged area. Under an operating microscope, the nerves are connected to the damaged cornea. It’s a months-long process though, as the cornea develops sensation and restoration at about one millimetre of the nerve per day.

“You connect the nerve to another nerve that is functioning and it will regenerate along the nerve that you put in, it’s almost like an extension cord and then it grows from where there’s feeling to no feeling onto the eye,” Dr. Asim Ali, a staff ophthalmologist, explained.

It’s not invasive at all – tiny incisions are made, then the spare nerves are harvested.

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The researchers say their findings could extend to restoring sensation to other parts of the face, the hand or even the leg. Similar operations are already offered to patients with facial paralysis.

The Canadian doctors described the surgical technique and their patient outcomes in the journal JAMA Ophthalmology and Plastic and Reconstructive Surgery.

carmen.chai@globalnews.ca
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