Signifi cant advancements have been made in understanding the genetic pathogenesis of ocular diseases, and gene replacement has been implicated as an potentially efficacious therapy. Because of its favorable anatomical and immunological characteristics, the eye has been at the forefront of translational gene therapy. Recent improvements have been made in the safety and specifi city of vector-based ocular gene transfer methods. The results from the first clinical trials have generated great interest and have demonstrated the safety and efficacy of intraocular administrations of viral vectors in humans.

Stem cells are undiff erentiated cells which have the ability to self-renew and diff erentiate into mature cells. They are highly proliferative, implying that an unlimited number of mature cells can be generated from a given stem cell source. On this basis, cell replacement therapy has been evaluated in recent years as an alternative for various pathologies. Cell replacement therapy hypothesizes that new retinal cells could be generated from stem cells so as to replace the damaged cells in the diseased retina. In addition, stem cells are able to perform multiple functions, such as immunoregulation, anti-apoptosis of neurons and neurotrophin secreting. With recent progress in experimental stem cell applications, several phase I/II clinical trials were approved and we have the promising and encouraging results from these stem cell clinical trials. This review summarizes the clinical developments of stem cells and retinal gene therapy in HRD. Keywords : Hereditery retinal dystrophies therapy