Bionic vision technologies: progress and perspectives on retinal prostheses and optogenetics for the treatment of advanced retinal degeneration.

Advanced degenerative retinal diseases [e.g., retinitis pigmentosa (RP) and age-related macular degeneration (AMD)] are characterized by irreversible photoreceptor loss, and conventional interventions rarely prevent progression to profound vision loss at advanced stages. Retinal prostheses and optogenetic therapies are two leading bionic strategies to bypass absent photoreceptors, yet both are limited by a shared "encoding-biointerface" bottleneck: converting external scenes into interpretable neural activity in surviving retinal circuits with adequate selectivity, safety margins, and long-term stability. This review critically compares the two approaches in spatial resolution, neural adaptation, and biosafety, while explicitly distinguishing clinical evidence from preclinical and proof-of-concept studies. Retinal prostheses provide near-term light perception and limited form vision but are constrained by current spread, non-selective pathway/axon recruitment, interface reactions, and cortical decoding burden. Optogenetic restoration offers cell-type-biased reactivation and potentially more physiological processing, but currently remains coupled to external light-delivery hardware and is limited by scattering, heterogeneous transduction, safety-limited irradiance, restricted dynamic range, and adeno-associated virus (AAV)-related inflammatory risk. We highlight emerging integrative directions, including opto-electronic hybrid interfaces, adaptive encoding, broadband subretinal nanomaterial-based photovoltaic nanoprostheses, and experimental acoustic modalities (e.g., focused ultrasound and sonogenetics), alongside ethical and accessibility considerations for translation.