New Retinal Implants Change the Way We Look at Bionics

By Rita Waimer

Vanessa Restrepo-Schild, a 24-year-old PhD student and researcher at Oxford University’s Department of Chemistry, recently developed a more comfortable retinal implant.

Retinal implants are used to help restore the function of light-activated cells in the back of the eye. These photoreceptor cells send an electrical signal to nerve cells that tell the brain to “see.” If these cells have been damaged, but the nerve cells or ganglia that transmit the signal are still working, direct stimulation of the retinal cells can restore vision to people with age-related macular degeneration or retinitis pigmentosa.

Earlier retinal implants have been made with metal or other hard materials that can damage the eye and lead to inflammation and scaring. The implant that Restrepo-Schild and her team have created is different, using softer biological materials that more closely match the natural human retina.

A Natural Fix

The new double-layered implant is designed to act like a camera. According to Restrepo-Schild, “the synthetic material can generate electrical signals, which stimulate the neurons at the back of our eye just like the original retina.” Each cell in the implant detects and reacts to light, just like the pixels on a camera sensor, and together they create a grayscale image.

The team’s implants are made entirely from biological cell membrane proteins and soft water droplets called hydrogels. These natural, biodegradable materials don’t contain foreign bodies or living cells, and are less invasive than mechanical devices. It’s far less likely that the human body will have an adverse reaction to the implant, making its use easier for patients and doctors alike.

Looking to the Future

Once fully developed and tested, these devices could be a pivotal first step in creating retinal and other implants that are more bionic, less invasive and more closely resemble human body tissues.

Restrepo-Schild’s study is published in Scientific Reports, and the team is already starting on the next phase of their work. The synthetic retinas have only been tested under lab conditions to date, but the team will begin to explore their use with living tissues, a vital step in demonstrating how the materials will perform as bionic implants. Future plans include the development of retinal implants that can recognize different colors and shapes, and expansion of testing to animal models and human clinical trials.