Solving corneal blindness with implantable video technology

Charles Yu, MD, seeks to treat corneal blindness by creating a small video projector implant for the eye. Illustration courtesy of Lauren L. Kalinoski.

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 an idea from one researcher may have an answer. Charles Yu, MD, assistant professor of ophthalmology, is leading an effort to take a novel electronic approach to treating corneal blindness. The implant includes a projector that transfers images from the outside world onto the retina.

The cornea is the clear, front part of the eye that functions similar to a window, helping focus images entering the eye onto the retina. 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, which 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 developing 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 fundamentally, 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.”

Charles Yu, MD, a former resident, joined the department as faculty in 2018.

A movie projector inside the eye

Yu’s electronic implant is comprised of two technologies, a wireless video receiver and a micro display. In his 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, 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 it 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, who has extensive experience in the development of visual prosthesis for retinal blindness. Palanker’s expertise has both helped and inspired Yu to determine the future path of his own research at the Mary M. and Sash A. Spencer Center for Vision Research at the Byers Eye Institute.

Charles Yu’s miniaturized projector designed for implant inside the eye displays various images.

Moving from proof-of-concept to patient care

The electronic implant would benefit patients by eliminating the need for corneal transplants, and their challenges with patient access, lifelong steroid therapy, and cost over the long term. It would allow developing countries to treat corneal blindness, a benefit that motivated Yu ever since he first went to Africa to perform cornea transplant surgeries. After his first trip there, he left excited that his team was able to perform so many surgeries, but when he returned a second time, he noticed that many of the transplants had failed from inadequate access to care. Seeing that previous patients had gone blind, it motivated him to identify new ways to treat corneal blindness that would not require extensive follow up.

Now working in the technology mecca 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 biocompatibility of his device. He is hopeful for the future of this ongoing research, seeing that much progress has already been made. Yu notes that while the initial cost of these devices will be high, with economies of scale they could become very affordable.

“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.”


Kathryn Sill is a web and communications specialist for the Byers Eye Institute in the Department of Ophthalmology, at Stanford University School of Medicine. Email her at