For the first time in the US surgeons used a rare procedure to help a blind woman regain her sight: they implanted her own tooth in her eye to hold a prosthetic lens in place.

60-year old Sharron "Kay" Thornton, of Smithdale, Mississippi, who had been blind for nine years, underwent the sight-restoring procedure, known as modified osteo-odonto-keratoprosthesis (MOOKP), at the Bascom Palmer Eye Institute at the University of Miami Miller School of Medicine earlier this month.

The Institute's chairman, Dr Eduardo C Alfonso, told the press that this was the first time MOOKP, which has been available only in a limited number of eye centres in Europe and Asia, has been used in the US.

Thornton said she was looking forward to seeing her seven youngest grandchildren for the first time. She lost her sight in 2000 as a result of a rare skin condition called Stevens-Johnson syndrome that destroys the cells on the surface of the eye causing severe scarring of the cornea.

"We take sight for granted, not realizing that it can be lost at any moment," said Thornton, "This truly is a miracle."

Corneal specialist Dr Victor L Perez performed a series of surgeries that involved implanting one of Thornton's teeth in her eye:

"For certain patients whose bodies reject a transplanted or artificial cornea, this procedure 'of last resort' implants the patient's tooth in the eye to anchor a prosthetic lens and restore vision," explained Perez.

"In Sharron's case, we implanted her canine tooth, her eyetooth," he added.

Hours following the last surgery on Labor Day, Thornton said she was able to recognize faces, and two weeks later, she was reading newsprint with a visual acuity of 20/70. Her sight is expected to improve further as the scars heal.

MOOKP was first developed in Italy and is used to help patients with end-stage corneal disease or who have suffered damage to the cornea where severe scarring blocks vision and corneal transplants are no longer an option yet inside the eye everything is healthy and working properly, including the optic nerve.

Severe scarring on the cornea, which is the transparent layer of skin on the outside surface of the eye where a contact lens would sit, can come from accidents like chemical injuries and thermal burns, or as a result of disease such as inflammatory and autoimmune disorders like Stevens-Johnson syndrome.

In MOOKP, which comprises a series of lengthy procedures, the surgeons first remove, shave and sculpt a tooth and surrounding bone, and then drill a hole through which to insert an an optical cylinder lens.

They bond the tooth and lens to make one "bio-integrated" prosthetic unit and then implant it under the patient's skin, either in the cheek or the shoulder.

In the meantime, an opthalmologist gets the surface of the eye ready to receive the implanted prosthesis by removing scar tissue in and around the damaged cornea.

About a month later, the surgeons take mucous material from inside the patient's cheek and use it to cover and rehabilitate the surface of the damaged eye.

Then, about two months after this, the surgeons conduct the final stage of the procedure: they remove the bio-integrated prosthetic unit (the bonded tooth and lens) from the patient's cheek or shoulder and implant it in the eye, carefully alinging the unit to the centre of the eye. They make a hole in the mucosa for the prosthetic lens, which protrudes from the eye slightly so that light can enter and the patient can see again.

When Thornton first approached Bascom Palmer six years ago, she underwent an ophthalmic evaluation where they conducted a stem cell procedure but that was unsuccessful. As she was not a candidate for corneal transplant, they referred her to Perez who was thinking about doing MOOKP.

Last year Perez underwent training in Europe with Italian ophthalmologist Dr Giancarlo Falcinelli, who developed the MOOKP procedure from the original OOKP technique developed in the 1960s by another Italian eye specialist, Professor Benedetto Strampelli.

However, not all surgeons feel positive about MOOKP.

A member of the American Academy of Ophthalmology, Dr Ivan Schwab, told CNN that they've known about MOOKP since the 1980s and view it with skepticism. It needs a large team and several operations, and although it seems to be reasonably successful on the small numbers of patients that have received it, it results in disfigurement.

Schwab said the procedure was just an "extreme variation on techniques we're already doing" and that the alternatives were nearly as good. But in defense of Perez and his team he said "they are working on the worst of the worst, people with no other alternatives".

Another doctor who brought MOOKP to England from Italy, Dr Christopher Liu from the Sussex Eye Hospital in Brighton, told CNN that he didn't think the procedure would take off in the US because it was too lengthy.

"Each stage takes hours to perform," said Liu , adding that although the person can see again, the eye does not look natural.

However, one patient at least is very happy that US surgeons made the effort. Thornton told the press:

"I'm so thankful that the doctors at Bascom Palmer never gave up on me -- they kept searching."

Thornton said she was excited about seeing her three grown children and nine grandchildren, and rediscovering simple joys like playing cards and watching clouds go by.

"Without sight, life is really hard. I'm hoping this surgery will help countless people," she said.

Source: Bascom Palmer Eye Institute, CNN.

Written by: Catharine Paddock, PhD