Electrical vs optogenetic restoration

The central modality question in vision restoration: write activity with electrical current (retinal or cortical prostheses) or with light on genetically or chemically photosensitized neurons. Electrical stimulation is mature, immediate, and hardware-defined but is limited by current spread, axon-bundle activation, and electrode count, and works regardless of cell biology. Biological (optogenetic or photoswitch) approaches promise cell-type specificity and potentially higher effective resolution with no penetrating array, but depend on surviving target cells, viral delivery, opsin performance, and external light hardware.

These are not strictly exclusive: both typically still need a camera-and-processor front end and a scene-encoding model, both are bounded by how much the surviving circuit and cortex can interpret, and hybrid concepts exist. Which wins where will likely depend on the disease, the disease stage, and how the cortex adapts.