This truly groundbreaking paper by M Mehdi Doroudchi, Kenneth P Greenberg, Jianwen Liu, Kimberly A Silka, Edward S Boyden, Jennifer A Lockridge, A Cyrus Arman, Ramesh Janani, Shannon E Boye, Sanford L Boye, Gabriel M Gordon, Benjamin C Matteo, Alapakkam P Sampath, William W Hauswirth and Alan Horsager demonstrates that channelrhodopsin-2, a cation channel from algae than can be gated/activated by light can restore both physiological and behavioral visual responses in mice with retinal degenerative disease.