Have Researchers at UMH Discovered a Cure for Blindness?

Researchers from the Miguel Hernández University of Elche (UMH) are participating in a project that could lead to a cure for blindness. The key seems to lie in an artificial vision system that communicates with the brain, which has been successfully tested on two blind individuals. The results, according to the university, are 'promising'.

The study results, involving laboratories worldwide, have been published in the journal Science Advances. They demonstrate how a new generation of visual neuroprostheses can engage in bidirectional communication with the brain. This dynamic interaction can directly converse with the visual cortex to achieve a more natural and functional artificial vision.

"A cortical artificial vision system attempts to emulate the natural vision process. It uses a small external camera integrated into somewhat conventional glasses that replace the retina. The information is electronically processed and converted into patterns of electrical stimulation sent to the part of the brain responsible for processing visual information, namely, the occipital cortex," explains UMH professor and study leader, Eduardo Fernández Jover.

"But vision is not a passive process; it's a constant exchange of signals and information between the eye and the brain," adds the expert, "so artificial systems must also fulfill this function and try to replicate the visual system's operation." In any case, it's not about "seeing again", but about regaining "functional vision" for simple tasks like orientation, mobility, reading large characters or numbers, etc.

The researchers explain that so far, all visual neuroprostheses are 'open-loop' and do not consider neuronal responses to electrical stimulation. However, when a device stimulates, the brain adapts, learns, and responds: "The neurons we are stimulating can become more sensitive or fatigued. Or perhaps, the signal we send today is not what the brain expects or needs tomorrow, because it has changed," comments Fernández Jover, who also belongs to the area of Bioengineering, Biomaterials, and Nanomedicine at CIBER (CIBER-BBN).

"This study shows that we can establish a bidirectional dialogue with the brain. While generating the electrical stimuli that create visual perceptions, we can record brain activity and adjust stimulation patterns based on the response of the neurons surrounding the electrodes, just as would happen under normal conditions," notes the UMH professor, emphasizing that "this closed loop takes advantage of the brain's ability to adapt and allows the transformation of the traditional monologue into a bidirectional dialogue between technology and the brain, which could help us achieve artificial vision more akin to natural vision."

The study was conducted in collaboration with the IMED Elche Hospital and involves the implantation of a very small device, only 4 millimeters on each side, containing 100 individual microelectrodes. For the implantation of the microelectrodes, researchers used a surgical robot and an advanced neuronavigation system that allows the procedure to be carried out in a controlled and safe manner.

Pablo González López, a team member and neurosurgeon at Doctor Balmis Hospital and IMED Hospitals, explains that "thanks to this technology, we can guide the insertion of electrodes in real-time with great precision and safety, allowing the entire implantation to be performed through a small hole of only 8 to 10 millimeters, avoiding the need for a craniotomy (opening of the skull). Thanks to this, study participants can be discharged early and experience fewer discomforts than in a typical postoperative period."

In 2021, the Biomedical Neuroengineering Laboratory at UMH successfully implanted a device in a blind person's brain capable of inducing the perception of shapes and letters with much higher resolution than previously achieved. Now, they have developed technology that can help distinguish between perceiving a flash and seeing the world. A system capable not only of "writing" in the brain by injecting electrical patterns that evoke visual perceptions but also of "reading" neuronal responses and adapting to them in real-time.

The UMH researcher explains that this technology can safely and stably induce visual perceptions: "The new system learns from the brain, and the brain learns from the system." Thanks to this, implanted individuals have been able to recognize various complex patterns, movements, shapes, and even some letters.

Currently, artificial vision implants are in the preclinical development stage and are not yet available to the general public. The ultimate goal is to replace the vision of people who lost their sight after having it, particularly due to degenerative retinal diseases or optic nerve damage, as they have no other treatment options.

In these cases, the brain still has the ability to process visual information, allowing the implant to send electrical signals to areas where light and shape can still be interpreted.

"In contrast, in people born blind, the visual cortex never develops the function of seeing," explains the UMH researcher. Those areas reorganize for other tasks, such as language or spatial recognition through hearing or touch. "Therefore, at least for now, an implant cannot 'speak' with a visual system that has never developed," notes Fernández Jover, "there is no prior code to communicate with."