Doctors helped two men suffering from progressive blindness to help regain some of their vision with the help of an experimental gene therapy.
After undergoing treatment to correct a faulty gene, the men were able to read two to four more lines on an optician's sight chart, which was a significant improvement since the doctors treated them. One man got treated more than two years ago, the Guardian reported.
Choroideremia is an X-linked disorder, which means that it is caused by a faulty gene, called CHM, on the X chromosome.
A genetically modified virus is used in the experimental therapy to smuggle healthy copies of the CHM gene into light-sensitive cells in the retina, and supporting tissue called retinal pigment epithelium.
Surgeons injected 10bn modified virus particles behind the retinas of the first six patients in the trial.
The injected viruses then infect the eye cells, which uses the new CHM gene to treat the genetic disorder.
The study has been published in the journal The Lancet.