A New Path to Restoring Vision: Chen Yang’s Lab Develops Flexible Retinal Prosthesis
By Choe de Leon
Humans process 85% to 90% of the world through their vision, making blindness due to degenerative eye diseases challenging to everyday life, according to researcher Chen Yang.
A study led by Chen Yang, Professor of Electrical & Computer Engineering, Chemistry, and Materials Science & Engineering, introduces a promising technology that could one day help restore vision for blind patients with degenerative eye diseases. With the work recognized for its multidisciplinary achievement and set for publication in Nature Communications, Yang reflected on an early moment in her retinal prosthesis research. She sat in a crowded restaurant in Paris to discuss her project with collaborators at the Institut de la vision when a group of blind individuals maneuvered inside, using one another for guidance.
“The people we wanted to help, in a such challenging situation, just sat next to us,” Yang said.
The work aims to address two main types of retinal degenerative disease: age-related macular degeneration and genetic disease retinitis pigmentosa. These diseases cause damage to photoreceptors, a photosensitive layer of neuron cells in the retina, preventing them from processing light.
“I think it’s very clear that blindness imposes a tremendous challenge for the quality of life of the patient,” Yang said.
This research builds on Yang Lab’s interest in using light and sound to regulate nerve activity. Her previous work focused on the brain, tissues, and cell cultures.
While her research is in the early stages, with testing done on rats (in vivo) and tissues (ex vivo), it introduces the feasibility of a flexible film prosthetic that restores vision. This film converts light energy to ultrasound signals, which is a unique approach to restoring vision. Developed in collaboration with a French vision solution company Axorus and Professor Serge Picaud at Institut de la Vision, the film was surgically implanted into rat retinas and tested in retinal tissue. The team stimulated the retinae and evoked neural responses associated with vision.
“The long-term goal is to show such stimulation can be used to restore vision in blind patients,” Yang said.
Publication may help Axorus with commercializing the technology as it develops, according to Yang.
Existing retina prothesis designs that have been tested to restore vision used electrode and photovoltaic materials, meaning the implants converted light signals into electrical current. These implants are rigid, which leads to a smaller implantable area and less biological compatibility. Yang’s material is foldable and can be implanted over large areas of the retina, restoring a greater field of vision, which is essential for supporting navigation in everyday life.
Yang explained that a healthy human retina can see with a resolution of five micrometers. Although their testing achieved around 50 micrometers, Yang’s approach can theoretically enable single cell stimulation, bringing the technology closer to natural retinal resolution.
“Our technology can achieve precision outperforming the existing technologies,” Yang said. “…The physics and the material [may] allow us to stimulate a single cell at the time.”
Previous attempts to solve the same issue were not successful enough. Food and Drug Administration-tested approaches yielded narrow fields of corrected vision or low improvement in acuity of vision.
“Because the outcome is not satisfying, all those devices the FDA approved have been discontinued,” Yang said. “So, we’re in a time that there is no officially FDA approved retina devices can be prescribed to a patient.”
While a substantial amount of research and testing lie ahead, the early results suggest that this may be a revolutionary application of materials science, neural modulation, and biomedical engineering.