Gene therapy injection in one eye surprises scientists by improving vision in both

Injecting a gene therapy vector into one eye of someone suffering from  LHON , the most common cause of mitochondrial blindness, significantly improves vision in both eyes, scientists have found. Saving sight with gene therapy is now a reality Patrick Yu-Wai-Man In a landmark phase 3 clinical trial, the international team, coordinated by Dr Patrick Yu-Wai-Man from the University of Cambridge and Dr José-Alain Sahel from the University of Pittsburgh and Institut de la Vision, Paris, successfully treated 37 patients suffering from Leber hereditary optic neuropathy (LHON) . Subject to further trials, the treatment could help thousands of people across the world to regain and retain some of their sight. The study, published today in the journal Science Translational Medicine , indicates that 78% of treated patients experienced significant visual improvement in both eyes. It suggests that the improvement in vision in untreated eyes could be due to the transfer of viral vector DNA from the injected eye. LHON affects a specific type of retinal cells, known as retinal ganglion cells, causing optic nerve degeneration and rapidly worsening vision in both eyes. Within a few weeks of disease onset, the vision of most people affected deteriorates to levels at which they are considered legally blind.