Organ transplantation not only works but can work well and the field is still in its infancy. Cell transplantation should eventually work as well or even better. This is another extraordinary field that is on the runway waiting to take off. Many labs through out the world are involved in this research. The major problem is how to deliver a foreign gene into retinal cells.
Viruses are the best taxis for gene delivery and the taxi fleet is improving continuously.
The first to be tried, an adenovirus, has the disadvantage of only working for short times because it does not actually penetrate into the chromosomes. A newer vector, an adeno-associated virus, has the advantage of placing foreign genes into chromosomes which adenoviruses don't do. This can greatly prolong the action of the gene. Unfortunately adeno-associated viruses tend to be rejected by the body. Another even more promising viral vector has recently been produced at the Salk Institute.