Key points from article :
A gene therapy has enabled people with a rare type of total colour blindness to faintly see red.
Small trial was performed on four people with achromatopsia, a rare condition caused by a single genetic mutation.
Researchers hoped that inserting working copies of the faulty gene into cone cells would provide some degree of colour vision.
Injected a virus carrying the correct gene into the subretinal area, home to cone cells, into one eye of each participant.
“The virus then enters the cells with the defective gene and corrects it,” says Ayelet Mckyton at the Hebrew University of Jerusalem.
No major vision changes were seen within hours, but some reported seeing shades of grey in the months that followed, says Mckyton.
After a series of tests, participants could see red objects against dark backgrounds in their treated eye.
Gene therapies probably won’t work for other types of colour blindness, as these aren’t caused by a single mutation.
Participants’ brain circuitry for colour vision may be relatively dormant and hasn’t been sufficiently activated, hence the limited effectiveness of the therapy.
Participants will be monitored for several years and may then have the injection repeated on their other, untreated eye, says Mckyton.
Study by Hebrew University of Jerusalem published in Current Biology.
