- In a pilot study, researchers said they were able to restore sight to people who were blind by using bioengineered cornea manufactured from pigs.
- The researchers said the new procedure is simpler and easier to access than current corneal transplants.
- Experts say more research is needed, but the new procedure could provide an alternative to some people who are blind or visually impaired.
Almost 13 million people around the world are blind due to cornea issues.
Currently, corneal transplants use human donors, but only one in 70 people can access this type of transplant.
Now, researchers are working on cornea transplant tissue that comes from a pig. If successful over the long term, the new procedure could give people worldwide access to sight-saving surgery.
The pig skin was highly purified and produced under strict conditions to make it viable for human use. The researchers said they successfully stabilized the collagen molecules to form a robust and transparent material that could withstand handling and implantation in an eye.
Two significant advantages to the bioengineered cornea are:
- Human corneas must be used within two weeks of being removed from a donor – the bioengineered corneas can be stored for up to two years
- The pig skin used to create the corneas was a byproduct of the food industry – making it easy to access and economically advantageous
“The bioengineered cornea is helpful in limited situations. It replaces the middle layer of the cornea,” said Dr. Kathryn Colby, a professor and chair in the Department of Ophthalmology at NYU Grossman School of Medicine. “If you think of the cornea as a sandwich, the top and bottom layers are the bread. The meat is in the middle. It is the meat where it can be helpful. Because it doesn’t have surface cells, it can’t replace the ‘bread’ layers. It could also be helpful for corneal scarring.”
The scientists also developed a new, minimally invasive treatment for keratoconus, a condition where the cornea becomes thin. This condition can lead to blindness.
The current treatment for the disease is a cornea transplant where the doctor removes the patient’s cornea and sews the donor cornea using surgical sutures. Typically, this surgery is completed at large university hospitals.
“For advanced diseases of the cornea like keratoconus or dystrophies, the bioengineered cornea is recommended over a human cornea, for several reasons,” Mehrdad Rafat, PhD, and Neil Lagali, PhD, researchers at Linkoping University, told Healthline. “The procedure with the bioengineered implant is less invasive, does not require sutures (stitches), and only needs a short course of postoperative medication. The procedure is more complicated for human corneas and wound healing takes longer. Also, there is a risk of rejection of the human tissue, but this is not an issue with the bioengineered material.”
Dr. Rafat and Dr. Lagali’s method does not involve removing the patient’s cornea. Instead, a small incision is made with a precision laser in most cases. They said a doctor can make the incision by hand with simple surgical instruments if needed. The doctor implants the bioengineered cornea into the existing cornea. No stitches are needed.
In the pilot study, researchers tested the procedure on pigs and found it was simpler than traditional implants. They then used it on 20 people who were blind, or nearly blind, from advanced keratoconus.
Researchers reported that all the surgeries were free of complications and wounds healed quickly. All study participants received eight weeks of immunosuppressive eye drops to prevent rejection.
In their two-year follow-ups, there were no reports of complications. During the two years after surgery, researchers said the thickness and curvature of the cornea were restored to normal.
Before the surgery, 14 of the 20 participants were blind. After two years, researchers reported that all of them had sight and three participants who were blind had perfect 20/20 vision.
Dr. Benjamin Bert, an ophthalmologist at Memorial Care Orange Coast Medical Center in California, typically performs four to six corneal transplants each month.
“In the United States, this would likely be used for emergency surgeries,” Bert told Healthline. “We are extremely fortunate as we have a great network of eye banks across the country and many people in the U.S. are organ donors. But this is a great alternative and would be something I would happily discuss with my patients.”
The scientists indicated they would need to complete a more extensive study. They also want to determine if the technology and technique could treat other eye conditions. The results would then be submitted to regulatory authorities and received approval before their methods could be used in healthcare.
Their goal is to have the invention widely available and affordable in all parts of the world.
“There is a shortage of corneal tissue in many countries, so having an alternative that could be used to restore sight is a major advancement,” said Dr. Bert. “Cornea blindness is readily treatable. It’s just a matter of having the tissue that is an issue for many.”