dear zahra, Progressive cone dystrophy as the name suggests is a progressive disease, however rate of progression varies from patient to patient. The good part is that these patients rarerly progress to total blindness and will retain a good part of their peripheral vision,which will sustain them in their daily activities especially in famililar surroundings.Fine visual activities like reading may not be an option in the long run.It may be useful to approach low vision clinics in your area to maximise the available vision and aid in his overall development appropriate for his age. Stem cell therapy is at best only an experimental therapy in the current stage of stem cell research. Dr Merine Paul.