Progress of the Intracortical Visual Prosthesis Project (ICVP): One-year update
A 3D rendering of a single WFMA implant alongside a representation of the approximate locations of the 25 arrays implanted in the visual cortex of the human subject.
In February, 2022, the ICVP consortium’s surgical team at Rush University Medical Center in Chicago, IL, performed the first ICVP implantation in a human volunteer who became functionally blind in middle age. The ICVP is not a single implant; rather, it consists of multiple Wireless Floating Microelectrode Array (WFMA) modules. A WFMA consists of a flat disk less than ¼” in diameter that contains electronics and an antenna, with 18 thin, and short, electrodes with active tips protruding from its bottom side into the brain: 16 electrodes with active tips, and 2 longer pins stabilizing the module so it remains in place. Permanently Implanted within the head, the WFMAs remain in place, and are wirelessly powered and activated by a special antenna coil placed on the scalp; pre-clinical tests have shown that they can continue to function for years. There is no connector on the person’s head, and no wires cross the skull or scalp. In this first implantation 25 WFMAs (total of 400 electrodes) were placed in the right side of the brain at the back of the head, the area of the brain that serves vision.
This was the first-ever implantation of WFMAs in a human, and we have learned many things. As far as the 25 implants themselves, we have learned that the modules and individual electrodes are all functional, and that their properties have not changed noticeably over the course of a year. What has not changed either are the visual perceptions caused by the electrical stimulation from the WFMA electrodes, as reported by our volunteer. Depending on which WFMA is being stimulated, the percepts, called phosphenes, were light or dark dots, small groups of dots, or larger areas in the periphery. Most electrodes within a WFMA produce similar phosphenes, appearing very close together; this closeness has made it hard to construct a detailed map of where they appear in the person’s visual field of view, and we continue to refine the map. Even with the crude map we currently have, when we connect a camera to the ICVP system, our volunteer could make out the individual fingers of their hand moving in front of the camera; a person standing in the middle of the test room; the locations of objects on a table; and simple geometric shapes. We expect that this will improve as we fill in greater detail in the phosphene map.
The ICVP consortium members and volunteer are very encouraged by the results thus far, and fully committed to learn as much as possible in the coming year. The team also hopes to implant additional volunteers and is actively recruiting potential participants for this clinical trial, sponsored by NIH and approved by the FDA and Rush University Medical Center Institutional Review Board. For additional information: htps://clinicaltrials.gov/ct2/show/NCT04634383 and htps://chicagolighthouse.org/news/icvp-qa/ . The ICVP consortium comprises five academic partners (Illinois Institute of Technology, Rush University Medical Center, The University of Chicago, University of Texas, Dallas, and Johns Hopkins University), The Chicago Lighthouse, and two small companies (Microprobes for Life Science, and Sigenics, Inc).
This was the first-ever implantation of WFMAs in a human, and we have learned many things. As far as the 25 implants themselves, we have learned that the modules and individual electrodes are all functional, and that their properties have not changed noticeably over the course of a year. What has not changed either are the visual perceptions caused by the electrical stimulation from the WFMA electrodes, as reported by our volunteer. Depending on which WFMA is being stimulated, the percepts, called phosphenes, were light or dark dots, small groups of dots, or larger areas in the periphery. Most electrodes within a WFMA produce similar phosphenes, appearing very close together; this closeness has made it hard to construct a detailed map of where they appear in the person’s visual field of view, and we continue to refine the map. Even with the crude map we currently have, when we connect a camera to the ICVP system, our volunteer could make out the individual fingers of their hand moving in front of the camera; a person standing in the middle of the test room; the locations of objects on a table; and simple geometric shapes. We expect that this will improve as we fill in greater detail in the phosphene map.
The ICVP consortium members and volunteer are very encouraged by the results thus far, and fully committed to learn as much as possible in the coming year. The team also hopes to implant additional volunteers and is actively recruiting potential participants for this clinical trial, sponsored by NIH and approved by the FDA and Rush University Medical Center Institutional Review Board. For additional information: htps://clinicaltrials.gov/ct2/show/NCT04634383 and htps://chicagolighthouse.org/news/icvp-qa/ . The ICVP consortium comprises five academic partners (Illinois Institute of Technology, Rush University Medical Center, The University of Chicago, University of Texas, Dallas, and Johns Hopkins University), The Chicago Lighthouse, and two small companies (Microprobes for Life Science, and Sigenics, Inc).