More than 500 million people around the world are either visually impaired or blind, but thanks to a technique developed by a team of Japanese scientists at Osaka University, there may be hope for a new treatment. The breakthrough, published in the journal Advanced Healthcare Material, demonstrates their success in growing a key part of the eye in a petri dish — the cornea.

The inside of your eye is a highly organized and complex system, composed of three basic layers that have an important function needed for visual processing, including the cornea as the outermost layer. These cells deteriorate with age, which is why figuring out how to regenerate CECs is the key to maintaining functional eyesight. All researchers need is a small sample of skin to regenerate corneal endothelial cells (CECs), which are responsible for keeping the window of the eye clear and preventing it from swelling.

After growing CECs in a petri dish over the course of several weeks, researchers implanted them in sheep that were born without corneas. The sheep’s vision was restored to 98 percent. After 28 days, the sheep’s eyes didn’t reject the CECs or become inflamed, proving to the team their lab-grown corneas were near identical to that of one naturally grown. They have yet to implant them into humans, but once they do, it may open up a huge door for the visually impaired, who are in need of a medical procedure to regain their eyesight.

“For years, we didn’t have anything to offer these patients — we’d transplant a cornea, it would work for a few weeks, then the blindness would return. It’s devastating,” Dr. Edward Holland, director of cornea services at the Cincinnati Eye Institute who was not involved in the study, said in an interview. “This takes the stem cell procedure to another level, giving us more options to offer patients.

In preliminary trials earlier this year in March 2016, the same research team grew sheaths of corneas for rabbits. Sheets of petri-grown corneas were implanted into the eyes of blind bunnies. Once the stem cells took hold of the rest of the rabbits’ eyes, their eyesight was completely restored and researchers published their findings in the journal Nature. Beyond corneas, researchers hope to grow retinas, lenses, and other key components of the eye for those who were born with or developed visual impairment.

Previous research led to the discovery of a hidden layer in the cornea that could help increase the understanding of corneal diseases. Read here.

Source: Qiao GG, Ozcelik B, and Brown KD, et al. Biodegradable and Biocompatible Poly (Ethylene Glycol)-based Hydrogel Films for the Regeneration of Corneal Endothelium. Advanced Healthcare Material. 2016.