Retinal transplant is a transplantation of photoreceptors survive but also that they connect to nerve cells in order to be able to transmit signals to the brain. It can be surmounted, photoreceptor transplantation may in time open the way to saving sight, either by inhibiting further degeneration or even by restoring some sight by having transplanted photoreceptor cells communicate with surviving retinal nerve cells.
The RPE cells are 'nurse' cells, which lie behind the photoreceptors and provide them with essential nutrients. The photoreceptor transplantation is not encountering unmanageable rejection difficulties as it causes less stimulation of the immune system. However, there is an even bigger challenge. It is not only necessary that transplanted photoreceptors survive but also that they connect to nerve cells in order to be able to transmit signals to the brain.