I think it’s interesting how they went about this. I don’t know if this is the best solution in the long run, but might be able to help people now.
Retinitis Pigmentosa is a genetic disorder, but the retinal damage develops progressively over time. People can develop symptoms as early as childhood or as late as middle age and eventually go blind. There are hundreds of genes mutations that are know to cause RP and it can be dominant, recessive, x-linked or spontaneously inherited. So for now I think it is difficult to target due to the degree of variability - the product would need to be customized for each patient. However, there is currently an FDA approved genetic therapy, Luxturna, which treats a specific genetic mutation for a different inherited eye disease, LCA, so seems like a viable option for other conditions.
In this study, instead of restoring function to the photoreceptors, they added a light receptive function to the RGC which are the cells that the photoreceptors link up to on the path to the brain. So like Nathan said, kinda genetic engineering because it alters the natural function of these cells.
The other interesting thing they did was use a video headset in conjunction with the genetic therapy. The altered cells could only detect one wavelength of light so the headset converted images into this monochromatic image at that specific wavelength so it could be detected. The vision was restored to a level of being able to interact with objects in the environment which is a vast improvement, but not to the degree of being able to read letters.
So again I could see how this may help people suffering now with the condition but I think ideally catching it early and correcting the mutation, thereby preventing the damage would be better.