Harvard Medical School scientists have successfully restored vision in mice by turning back the clock on aged eye cells in the retina to recapture youthful gene function.

The team’s work, described Dec. 2 in Nature, represents the first demonstration that it may be possible to safely reprogram complex tissues, such as the nerve cells of the eye, to an earlier age.

In addition to resetting the cells’ aging clock, the researchers successfully reversed vision loss in animals with a condition mimicking human glaucoma, a leading cause of blindness around the world.