Source: Johns Hopkins University
Date: July 15, 2010
Summary:
A study published July 15 in the journal Neuron, provides new hope to people who have severe vision impairments or who are blind. The study shows mice without rods and cones function can still see -- and not just light, but also patterns and images -- thanks to a third kind of photosensitive cell in the retina. Johns Hopkins University researchers found that mice that didn't have any rods and cones function could still see -- and not just light, but also patterns and images -- courtesy of special photosensitive cells in the rodents' retinas. Until now, it was presumed that those cells, called intrinsically photosensitive Retinal Ganglion Cells, (or ipRGCs), didn't play a role in image formation, but instead served other functions, such as dictating when the animals went to sleep or woke up. (All mammals, including humans, have ipRGCs, as well as rods and cones.)
