The electrical cochlear implant (eCI) has restored speech understanding to the majority of the one million patients worldwide who would otherwise be deaf. However, hearing with an eCI is far from normal and patients report an unmet medical need to understand speech in the presence of background noise. This is due to the wide spread of excitation around each electrode contact, which limits the transfer of sound frequency information. Future optical cochlear implants (oCI) will use light instead of electricity because light can be spatially confined and will enable hearing restoration with finer tonotopic resolution. Photosensitization of the cochlea will be achieved by optogenetic modification of spiral ganglion neurons using an optogene therapy. This chapter discusses the last decade of development of an oCI and outlines the remaining challenges for it to become a new clinical standard in hearing rehabilitation.