Researchers from Linköping University in Sweden unveiled a medical procedure involving the use of transplanted artificial pig collagen cornea to restore 20/20 vision for patients suffering from an eye disease called keratoconus.
In a recent surgery, pig collagen corneas were transplanted into the eyes of visually impaired patients, some of whom had eyesight so bad that they were legally blind.
Doctors dissolved pig skin tissue to extract collagen, purified it, and then used it to make a hydrogel, which essentially mimics the human cornea. It was then inserted into pockets of the patient’s cornea to thicken it out and reshape it to restore the cornea’s function.
The procedure worked with most of the patients, improving their average visual acuity to 20/58 with glasses, meaning they need to be twenty feet away to see an object that people can normally see from fifty-eight feet away.
They never fully regained eyesight, but it was much improved in comparison to ptients’ eyeight prior to the surgery.
After two years, a review indicated that patients still retained these improvements, including three who even gained 20/20 vision, meaning they now have the clarity or sharpness of vision of a “normal” person despite having been legally blind (20/200 vision).
Furthermore, although their corneas now technically contain foreign biological material, because collagen is a structured protein that lacks individual cells, the patient’s immune system didn’t reject the implant.
It was reported that all of the fourteen initially blind subjects had a final mean best-corrected vision (spectacle or contact lens) of 20/36, and tolerance to contact lens wear had been restored.
The Keratoconus Vision disorder
Keratoconus is an eye disease involving a condition in which the cornea (the clear, dome-shaped front surface of your eye) becomes thinner and gradually bulges outward into a cone shape.
Upon contraction, the patient’s clear protective outer layer of the eye becomes cloudy or distorted either due to damage or disease. More than twelve million people around the world have corneal blindness.
Keratoconus affects up to two out of one thousand people, and it requires surgery to remove a full-thickness portion of the malfunctioned central cornea and replace it with donor tissue.
Because tissues require a human donor, only one out of every seventy people in need of care receive such a tissue donation because there aren’t many cornea donors around. In many lower-income nations, the cost of the operation further complicates access to treatment.
Pig Collagen Cornea implant potentially effective against keratoconus
Being a by-product of the food industry, pig collagen cornea is largely available and much more affordable in comparison to donor tissue.
According to researchers, cornea implant surgery has been shown to restore vision loss through the use of an approach that may possibly be just as or even more effective, safer, and widely available than donor cornea transplantation. It may potentially also be a simpler procedure.
Mehrdad Rafat, a researcher at Linköping University Sweden said, “I remember the first time that the first implant was implanted in one of the patients, I couldn’t sleep. I was awake all night, just waiting for the surgeon to let me know…how [the surgery went.]”
When sight was restored, “it was amazing, we got much better results than we expected,” he added.
Although eye surgery sounds complicated and risky, the operation only took about thirty minutes per patient whereas conventional cornea transplants from human donors can take a couple of hours.
Rafat and his team are uncertain what the final cost of the procedure will be but say it should be more affordable than donor transplants, which can cost tens of thousands of dollars in the US.
New cornea implant not as ground-breaking as it seems
Esen Akpek at Johns Hopkins University in Maryland says the new cornea may not be as ground-breaking as it initially seems.
“Those with keratoconus can often be fitted with custom contact lenses, and…previous alternatives to donor corneas have been engineered but didn’t take off,” she said.
“It will not cure anyone that cannot be cured with the currently available technology,” Akpek added.
Currently, it’s not at all clear whether this procedure would be effective for patients with forms of corneal disease other than keratoconus, such as those with corneal scarring from bacterial or viral infections.
Researchers noted that if approval for new trials is granted, further research might hopefully reveal the success of cornea implants in the treatment of other corneal diseases, as well. However, this has yet to be proven and further studies are needed.
Currently, experts are focused on replicating the present results in a much larger sample of one hundred patients.