This publication "Restoration of visual function by transplantation of optogenetically engineered photoreceptors" in Nature Communications of October 4, shows that structural and functional retinal repair is possible by combining stem cell therapy and optogenetics.
The authors are Marcela Garita-Hernandez,Maruša Lampič, Antoine Chaffiol, Laure Guibbal, Fiona Routet, Tiago Santos-Ferreira, Sylvia Gasparini, Oliver Borsch, Giuliana Gagliardi, Sacha Reichman, Serge Picaud, José-Alain Sahel, Olivier Goureau, Marius Ader, Deniz Dalkara & Jens Duebel

You can download here, following this link this publication https://www.nature.com/articles/s41467-019-12330-2

Furthermore, you will find here an important and useful blogpublication on the topic by Deniz Dalkara
https://bioengineeringcommunity.nature.com/users/318968-deniz-dalkara/posts/54399-gene-therapy-meets-cell-therapy-in-the-fight-for-sight