Engineered adeno-associated virus ( mediated gene therapies) are now being used with great success for patients with inherited eye diseases.Live viruses are injected directly into the retina, which is an invasive process, and has been carried out over many years however, with not as much success as now. Previously the live virus ( carrying normal genes to the retinal cells that need rebuilding) never quite managed to reach all of the defective cells thereby limiting the overall success for the patient after completion.
The last six years have proved a busy research period to address this issue of reaching all the RPE or photoreceptors and transduce a small fraction of the retina. Dense tissue penetration has up to now been a barrier for complete and successful gene delivery.
Five variants out of one hundred million variants of adeno-associated virus were chosen that proved they were able to penetrate the retina and carry different proteins on its coating and from these, the best three were used in mouse trials to transport genes to assist in curing heriditary conditions such as X-Linked Retinoschisis and Leber's Congenital amaurosis. Delicate cells of the retina are not invaded and the whol procedure takes just over a quarter of an hour and patients can be released to return home the same day.