A chemical injected into the eyes of blind mice restores the animals' sensitivity to daylight.

Richard Kramer at the University of California, Berkeley, and his colleagues tested a small synthetic molecule called DENAQ, which interacts with retinal ganglion cells and changes shape when exposed to white light of moderate intensity. In mice missing the light-sensing rod and cone cells in the retina and treated with DENAQ, light altered the interaction between the chemical and retinal ganglion cells so that the cells, which normally do not respond to light, became responsive. These animals were also more active when exposed to light.

The chemical works for several days, and only in retinas with degenerated rods and cones. DENAQ could be a possible drug candidate for the treatment of blinding diseases such as age-related macular degeneration, the authors say.

Neuron 81, 800–813 (2014)