A movie projector inside the eye
Corneal blindness is a leading cause of blindness worldwide. More than 12 million patients remain on cornea transplant waitlists while suffering from corneal blindness, but one researcher may have an answer. Charles Yu, MD, assistant professor of ophthalmology, is leading a novel electronic approach to treating corneal blindness, by implanting a small video display into the eye.
The cornea is the clear, front part of the eye that functions similar to a window. It helps refract light that enters the eye. While it can heal quickly from minor injuries, a major injury or disease can cause scarring, appearing as a white, clouded film, which then causes blindness.
“All current strategies for corneal blindness focus on restoring clarity to the cornea, by transplanting on a clear donor cornea or by sewing in a plastic replacement,” Yu said.
He notes corneal transplants have significant limitations. Transplants require donors, which require extensive logistics for harvesting, screening and delivery, and this can cause patients to be put on a waitlist until one is available. Outside of the U.S. it is hard to get a cornea transplant, and some cultures are averse to organ donation, resulting in a severe shortage of tissue. Many less developed countries lack the resources to create a distribution and waitlist system at all.
Even in the U.S. there are many challenges. More severe cases of corneal scarring cannot be transplanted due to high risk of rejection. Corneal transplants require lifelong follow up and are always at risk of long-term rejection. Cornea transplantation is often unsuccessful in pediatric patients.
However, it turns out that corneal clarity is not necessary for high quality vision as long as a clear image can be delivered to the retina. “Electronic displays can be used to bypass corneal blindness,” Yu said. “By using electronic implants, we avoid the need for transplants and their limitations entirely.”
A movie projector inside the eye
Yu’s electronic implant is comprised of two technologies, a wireless video receiver and a micro display. With this innovative approach, a patient would wear a camera built into glasses or a contact lens. The camera would then transmit wirelessly to a small video display inside the eye and that image would project onto the retina. This would allow people with corneal opacity to see, even with closed eyelids.
During his ophthalmology residency training at Stanford, Yu completed a research project using Google Glass, a smart glasses device that is used for augmented reality. Seeing that this device allowed patients to view video on a pair of eyeglasses, Yu began brainstorming ideas, and that was when he first thought of implanting a small television-like device into the human eye. Six years later, his dreams are gaining traction and he is hopeful will become reality.
To put this novel device together, Yu has been sourcing components from electronics manufacturers.
“Almost every year there are upgrades in technology, whether that be smaller video displays or brighter screen colors,” Yu said. “It is promising for the future of our patients to see these continuing improvements to product performance and function.”
He is aided in his efforts by Daniel Palanker, PhD, professor of ophthalmology and director of the Hansen Experimental Physics Laboratory, who has extensive experience in the development of visual prostheses for retinal blindness. Palanker’s expertise has both helped and inspired Yu to push his electronic implant solution forward.
Moving from proof-of-concept to patient care
The electronic implant would benefit patients by eliminating the need for cornea transplants and their issues of patient access, lifelong steroid therapy, and cost over the long term. Yu notes that while the initial cost of these devices will be high, with economies of scale they could become very affordable. An implant would allow less developed countries to treat corneal blindness, a benefit that motivates Yu ever since he first went to Africa to perform cornea transplant surgeries.
After his first trip to Africa he left excited that his team had performed so many surgeries, but when he returned for a second visit he noticed that many of the transplants had failed from inadequate access to care. Seeing previous patients going blind motivated him to identify new ways to treat corneal blindness that would not require extensive follow up.
Now working in the technology heaven of Silicon Valley, Yu has the ability to access the latest technologies from start-ups. He also collaborates with a local research and development subsidiary of the company Gore-Tex on material sciences, critical to the biocompatibility of his device. He is hopeful for the future of this ongoing research, especially seeing that much progress has already been made.
“This technology can fundamentally change the way we treat corneal blindness,” Yu said. “My hope is that in a few years we are able to transition this device to patients, so now it’s just a matter of pushing hard to make that happen.”