Could Electrical Stimulation Repair Optic Nerve Damage? Engineers Map the Visual Pathway's Language

Engineers at UC San Diego are developing biocompatible electrode arrays that could electrically stimulate and regenerate the optic nerve, a critical step toward making whole-eye transplantation actually restore sight rather than just anatomical viability.

The Challenge

The optic nerve is a 4.5-5 cm cable carrying over one million axons, making it 'probably the densest bandwidth cable in our nervous system.' Once cut by trauma or disease, the nerve cannot repair itself and vision cannot be restored. While the first whole-eye transplant was achieved in 2023, the procedure cannot yet restore sight.

The Technology

Shadi Dayeh's team has developed ultrathin, flexible electrode arrays that wrap around the optic nerve and sit on the visual cortex. The arrays send electrical pulses and record responses, allowing researchers to map how visual signals are encoded in the optic nerve and represented in the visual cortex.

'The idea is not just to record, but to build a code book across the visual pathway,' says Dayeh.

The VISION Initiative

The work is part of a multidisciplinary initiative called VISION (Viability, Imaging, Surgical, Immunomodulation, Ocular preservation, and Neuroregeneration) that aims to make whole-eye transplantation restore actual vision.

The Foundation

The team recently completed a foundational step: mapping how changes in light, color, and frequency affect the visual axis from retina to optic nerve to brain. This 'visual language' codebook is essential for understanding how to electrically stimulate the nerve to send meaningful visual signals to the brain.

Source: IEEE Spectrum