Blind Volunteers Pioneering New Visual Neuroprosthesis at UMH

Blindness significantly impacts individuals’ lives, and researchers are making strides to address this issue. The Biomedical Neuroengineering Lab at Miguel Hernández University of Elche (UMH) has developed a new generation of visual neuroprostheses that communicate with the brain in real time. This innovative approach aims to restore functional vision for individuals who have lost their sight.

A study published in Science Advances highlights the progress achieved at UMH, showcasing a system capable of two-way communication with the visual cortex. This interaction is designed to replicate the natural visual process, showing promising results in two blind volunteers. According to Eduardo Fernández Jover, a professor at UMH and the study leader, “A cortical artificial vision system seeks to emulate how natural vision works.” The system incorporates a small external camera embedded in conventional glasses, which replaces the retina. The captured information is transformed into electrical stimulation patterns sent to the brain’s occipital cortex, the area responsible for visual processing.

The researchers emphasize that vision is not a passive experience but an active exchange of information between the eyes and the brain. “Artificial systems must reproduce this feedback loop to better mimic how the visual system truly functions,” Fernández Jover states. The primary goal is not merely to “see again,” but to regain functional vision sufficient for essential tasks such as navigation, mobility, and reading large characters.

Historically, existing visual neuroprostheses have operated as “open-loop” systems. These systems did not take into account how neurons adapt to electrical stimulation. Fernández Jover explains, “When a device stimulates the brain, the neurons adapt, learn, and respond.” Consequently, the neurons can become more sensitive or fatigued, leading to variations in how they respond to signals over time.

The research team has taken a significant step forward by establishing a true two-way dialogue with the brain. This closed-loop approach allows the system to not only generate electrical impulses that evoke visual perceptions but also to record brain activity and adjust stimulation patterns based on nearby neurons’ responses. “This dynamic conversation between technology and the brain brings us closer to natural vision,” he adds.

Innovative Surgical Techniques Enhance Safety and Precision

The study, conducted in collaboration with IMED Elche Hospital, involved the implantation of a tiny, 4-millimeter-wide device containing 100 microelectrodes. Utilizing advanced neuronavigation systems and surgical robots, the procedure was performed with high precision. Pablo González López, a neurosurgeon at Hospital General Universitario Dr. Balmis, explains, “This technology allows us to guide electrode insertion in real time with great precision.” The implantation requires only a small opening of 8-10 millimeters, avoiding the need for extensive craniotomy, which contributes to reduced postoperative discomfort and earlier discharge for participants.

The ongoing research builds on previous successes; in 2021, the UMH lab successfully implanted a device in a blind volunteer, leading to the perception of shapes and letters with remarkable resolution. The current development aims to bridge the gap between perceiving flashes of light and experiencing true visual perception. The system not only stimulates the brain but also learns from neuronal responses, adapting in real time.

“This technology can safely and stably induce visual perceptions,” Fernández Jover states. The bidirectional exchange allows participants to recognize complex patterns, movements, and shapes, including some letters. By analyzing neural activity, the researchers can predict whether specific electrical stimulation will evoke a visual perception, including its brightness and the number of individual perceptions. This capability enables the system to fine-tune stimulation parameters automatically, enhancing adaptation and accelerating learning for users.

While these findings represent a promising advancement toward developing a visual neuroprosthesis for individuals with blindness or low vision, Fernández Jover cautions that challenges remain. “It is essential to advance carefully and avoid creating false expectations —this is still ongoing research.” Currently, these artificial vision implants are in the preclinical stage and are not yet available to the public.

The ultimate aim is to restore vision for those who once had sight but lost it due to degenerative retinal diseases or optic nerve damage, conditions that currently lack treatment options. In such cases, the brain retains the ability to process visual information, allowing the implant to transmit electrical signals to areas still capable of interpreting light and shapes.

In contrast, individuals born blind have a visual cortex that has not fully developed the ability to see. These regions often reorganize for other functions, such as language or spatial awareness through other senses. “For now, an implant cannot ‘speak’ to a visual system that never developed—there is no pre-existing code to communicate with,” explains Fernández Jover.

The research was conducted by a dedicated team at UMH, including Fabrizio Grani, Cristina Soto Sánchez, Alfonso Rodil Doblado, and Rocío López Peco. They express gratitude to the volunteer participants and their families for their commitment throughout the research process, as well as to the medical staff at IMED Elche Hospital for their clinical support.

This groundbreaking work continues to pave the way for future advancements in visual neuroprosthetics, offering hope to those affected by vision loss. More information about the study can be found in the article titled “Neural correlates of phosphene perception in blind individuals: A step toward a bidirectional cortical visual prosthesis,” published in Science Advances in March 2025.