Nearly 13 million people worldwide are blind because their corneas, the clear outer layer of the eye, are damaged or diseased. The only way to restore vision is by cornea transplant from a human donor. But only one in 70 patients achieves it. In addition, most of those who need corneal transplants live in low- and middle-income countries where access to treatment is very limited.
But there may be an alternative. Although this is a pilot study, a bioengineered cornea has restored sight to 20 people with damaged corneas, most of whom were blind before receiving the implant.
So far, 20 people who are blind or are about to lose their sight due to advanced keratoconus have participated in this pilot clinical study and have received the biomaterial implant. The operations were uncomplicated, the tissue healed rapidly, and an 8-week course of immunosuppressive eye drops was sufficient to prevent implant rejection. The patients were followed for two years, and no complications were observed during that time.
The study, jointly led by researchers from Linköping University (LiU) and LinkoCare Life Sciences ABpublished in “Nature Biotechnology”.
The cornea is mainly made up of a protein, collagen. To design an alternative to the human cornea, the researchers used collagen molecules derived from pig skin, highly purified and produced under strict conditions for use in humans. The pig skin used is a by-product of the food industry, making it easily accessible and economically advantageous.
The promising results bring hope to those with corneal blindness and low vision by providing a bioengineered implant as an alternative to transplanting donated human corneas, which are in short supply in countries where they are most needed.
In the process of constructing the implant, the scientists stabilized loose collagen molecules into a robust, transparent material that could withstand handling and implantation in the eye.
And while the donated corneas must be used within two weeks, biocorneas can be stored for up to two years before use.
“The results show that it is possible develop a biomaterial that meets all the criteria to be used as a human implant, that can be mass-produced and stored for up to two years and thus reach more people with vision problems. This avoids the problem of a shortage of donated corneal tissue and access to other treatments for eye diseases,” says Neil Lagali, professor in the Department of Biomedical and Clinical Sciences at LiU, one of the study’s investigators.
The safety and efficacy of implants bioengineering they have been at the core of our work,” says Mehrdad Rafat, the researcher behind the design and development of the implants.
Biocorneas can be stored for up to two years before use
“We have made significant efforts to ensure that our development is widely available and affordable for everyone and not just the wealthy. That is why this technology can be used in all parts of the world », he says.
Researchers have also developed a new, minimally invasive approach to treat kidney disease. keratoconus, in which the cornea becomes so thin that it can cause blindness. Currently, the cornea of a patient with advanced keratoconus is surgically removed and replaced with a donor cornea, which is sewn in place using surgical sutures. This type of surgery is invasive and is only performed in large university hospitals.
‘A less invasive method could be used in more hospitals, helping more people. With our method, the surgeon does not need to remove the patient’s own tissue. Instead, a small incision is made, through which the implant is inserted into the existing cornea,” explains Neil Lagali, who led the research group.
Less invasive method could be used in more hospitals, helping more people
With this new surgical method no stitches are needed. The incision in the cornea can be made with great precision thanks to an advanced laser, but also, when necessary, by hand with simple surgical instruments. The method was first tested in pigs and was found to be simpler and potentially safer than a conventional corneal transplant.
The new system and implants were used by surgeons in Iran and India, two countries where many people suffer from corneal blindness and low vision, but where there is a significant lack of donated corneas and treatment options.
In addition, unlike conventional cornea transplants, in which you have to take medications for several years, in this case they are not necessary.