Vision restoration for individuals affected by retinal degeneration has taken a promising leap forward, thanks to advancements in optogenetics. Researchers Dr. Himanshu Bansal and Gur Pyari, led by Professor Sukhdev Roy from the Dayalbagh Educational Institute, Agra, India, have conducted a detailed theoretical study showing how light-sensitive proteins called channelrhodopsins, which act as light detectors in cells, especially ChRmine, the novel red-shifted opsin and its specially designed variants, can help restore vision under ambient lighting conditions. The study, published in Scientific Reports, offers insights into vision-restoration that does not require any bulky goggles, making life easier for millions of people.
The research examines the challenges of restoring vision using optogenetics, a technology that uses light-sensitive proteins to activate nerve cells in the retina, which is the light-sensitive layer of tissue at the back of the eye. Traditional methods faced issues such as requiring very bright light, working only within a limited range of light colors, and reacting too slowly to changes in light. The first successful human clinical trial of optogenetic therapy on a blind patient was reported in the journal Nature Medicine in 2021. Visual function could be partially resotred with the use of specially designed goggles that could detect local changes in light intensity and project appropriate light pulses onto the retina in real time, to trigger optogenetically transduced retinal ganglion cells using ChrimsonR opsin. The present study marks a significant improvement and highlights how ChRmine with improved light sensitivity and robustness to elicit action potentials, can function effectively in everyday lighting, such as sunlight and white light, using much less light than earlier methods. This breakthrough marks a big improvement in making the process more natural and user-friendly.
One of the most remarkable discoveries is ChRmine’s ability to activate nerve cells with extremely low levels of light, i.e, the amount of light required is minimal. These levels are much lower than the brightness of a cloudy day. This means that devices using ChRmine could work without needing extra artificial lighting, which is often inconvenient and uncomfortable for users. Professor Roy noted, “This marks a significant change in optogenetics, as we can now work towards integrating natural light conditions into devices that help restore vision.”
The researchers also studied improved versions of ChRmine, including hsChRmine, a faster-acting variant called the high-speed ChRmine mutant. This version reacts quicker and can work across a broader range of light colors. While ChRmine can stimulate nerve cells to fire signals, which are the messages sent by neurons, at a speed similar to natural processes, the high-speed variant can do this almost twice as fast, improving the quality of vision restoration. These features are essential for helping individuals regain the ability to see colors and movement more clearly.
The study’s simulations also showed that using light with a mix of wavelengths—a range of colors, like the light found in natural sunlight—offers significant benefits compared to devices that rely on narrow bands of light, such as light-emitting diodes, which produce light of a specific color. ChRmine responded much more strongly to this type of mixed light, creating several times the response compared to other methods. Professor Roy explained, “Using light that spans a wider range of colors is a major advancement. It helps us achieve high-quality vision restoration while using much lower light levels, which keeps the eye safe from heating and photodamage and reduces dependence on artificial lighting.”
In summary, Professor Roy’s study not only highlights ChRmine’s potential for vision restoration without invasive surgery, which means no need for major operations, but also points to exciting possibilities for future developments in optogenetics. By combining high sensitivity to light intensity and color, quick reactions, improved quality and the ability to work with natural lighting, ChRmine and its improved versions could transform treatments for people with vision loss. The findings represent an important step toward creating affordable and effective optogenetic retinal prostheses that improve the quality of life for those with visual impairments.
Journal Reference
Himanshu Bansal, Gur Pyari and Sukhdev Roy, “Theoretical prediction of broadband ambient light optogenetic vision restoration with ChRmine and its mutants.” Scientific Reports, 2024. DOI: https://doi.org/10.1038/s41598-024-62558-2
About the Authors
Professor Sukhdev Roy received the B.Sc. (Hons.) Physics from Delhi University in 1986, M.Sc. Physics from Dayalbagh Educational Institute (DEI), Agra, India, in 1988, and PhD. from IIT Delhi in 1993. He is at present a Professor and Head of the Department of Physics and Computer Science, at DEI, Agra, India. He has been a Visiting Professor at Harvard, Waterloo, Würzburg, Regensburg, MPI for the Science of Light at Erlangen, Osaka, Hokkaido, City University and Queen Mary University of London, and an Associate of the International Centre for Theoretical Physics, Trieste, Italy. He is the recipient of the AICTE Career Award for Young Teachers in 2001, JSPS Invitation Fellowship, Japan in 2004, H.C. Shah Research Endowment Prize by Sardar Patel University in 2006, the 1st IETE B.B. Sen Memorial Award in 2007, IETE-Conf. on Emerging Optoelectronic Technologies Award in 2012, IETE-M. Rathore Memorial Award in 2016, the Systems Society of India’s National Systems Gold Medal in 2016, and DEI’s Distinguished Alumni Award in 2021, He also has been awarded eight best paper awards in international and national conferences. He has published over 200 research papers in reputed journals and conference proceedings, 11 book chapters and has six UK design patents on drone technology. He chaired the 8th World Conference and Expo on Nanoscience and Nanotechnology, Philadelphia, USA in 2020. He delivered the UN International Year of Light Commemorative Keynote Address at the Convocation of the International Council of Academies of Engineering and Technological Sciences Inc. (CAETS), in 2015, and was an Invited Speaker at the Annual Meeting of the American Physical Society, in 2008. He is an Associate Editor of IEEE Access, Guest Editor of the March 2011 Special Issue on Optical Computing in IET Circuits, Devices and Systems journal (UK), Senior Member IEEE and Fellow of the Indian National Academy of Engineering, the National Academy of Sciences, India, IETE (India), SPIE and Optica, and a Distinguished Fellow of the Optical Society of India.
Dr. Himanshu Bansal received the B Sc. from Dr B. R. Ambedkar University, Agra, India in 2015, MSc. in Physics and PhD from Dayalbagh Educational Institute, Agra, India in 2017 and 2023, respectively. He was awarded the Indian Science Congress Association Young Scientist Award in Physical Science in 2023, Best PhD Thesis Award at the 6th IEEE International Workshop on Recent Advances in Photonics at IIIT Allahabad, in 2023, two Best Paper Awards at International Conferences in Photonics and the DST-INSPIRE Fellowship from 2012-2022. He is at present a Research Associate at the Center for Neuroscience, Indian Institute of Science, Bengaluru.
Gur Pyari received the BSc., (Hons.) in Physics and M.Sc. Physics from Dayalbagh Educational Institute, Agra, India in 2016 and 2018, respectively. She is a Research Scholar in the Department of Physics and Computer Science, DEI, Agra, India. She was awarded the Best Paper Award at the 6th IEEE International Workshop on Recent Advances in Photonics (WRAP) at IIIT Allahabad, in 2023. She was a UGC-SAP Research Fellow from 2018-2022 and is the recipient of Junior and Senior Research Fellowships by the Department of Science and Technology, Government of India, from 2022-25.
