Single gene therapy injection surprisingly boosts vision in both eyes

This latest study was conducted by scientists at the University of Cambridge, the University of Pittsburgh and Paris’ Institut de la Vision, and focuses on a form of inherited vision loss called Leber hereditary optic neuropathy (LHON).

This affects around one in 30,000 people and usually occurs in young folks aged in their 20s and 30s, destroying their retinal ganglion cells and in turn the optic nerve. Once the condition takes hold, vision can deteriorate to the point where the subject is considered legally blind in just a matter of weeks, with recovery occurring in less than 20 percent of cases.

The majority of patients suffer from the same mutation affecting the MT-ND4 gene, so the researchers were hopeful of targeting this mutation as a way of improving treatment outcomes for sufferers of LHON.

They trialed their gene therapy as part of a study involving 37 patients who had suffered vision loss in the preceding six to 12 months. This meant injecting a viral vector packed with a modified complementary DNA called rAAV2/2-ND4 into the vitreous cavity at the back of just one eye, with a sham treatment injected into the other eye.

“We expected vision to improve in the eyes treated with the gene therapy vector only,” says study author Dr Yu-Wai-Man. “Rather unexpectedly, both eyes improved for 78 percent of patients in the trial following the same trajectory over two years of follow-up.”