Optogenetic vision restoration: translational barriers and emerging therapeutic strategies.

Optogenetic gene therapy has emerged as a mutation-agnostic therapeutic modality for vision restoration in advanced retinal degenerative diseases, where conventional gene replacement strategies are no longer applicable. By introducing light-sensitive opsins into surviving retinal neurons using viral vectors, this approach restores photosensitivity after photoreceptor loss. Advances in opsin engineering, vector design, and cell-specific targeting have accelerated the translation of optogenetics from proof-of-concept studies to an expanding clinical pipeline. This review summarizes recent progress in optogenetic vision restoration, focusing on the evolution of opsin technologies, retinal target cell selection-including retinal ganglion cells, bipolar cells, and residual cone photoreceptors-and viral vector platforms for retinal gene delivery. We also discuss key translational and drug development challenges, including insufficient light sensitivity, interspecies differences, immune responses to viral vectors and microbial proteins, and the lack of standardized clinical endpoints for patients with profound visual impairment. Addressing these barriers will be essential to establishing optogenetics as a clinically viable therapeutic modality and to enabling next-generation vision restoration therapies.