Figure 1.

Retina schematic. (A) Diagram of a normal healthy retina. Light passes through the retina, entering through the retinal ganglion cell (RGC) layer to reach the light sensitive photoreceptors, the rods and cones, in the outer retina. Visual information is sent from the photoreceptors to the bipolar cells where the ON/OFF processing begins. Ganglion cells are the terminal retinal signal recipients and they relay onto neurons in the lateral geniculate nucleus in the thalamus. Panels (B,C) depict the degenerate retina without photoreceptors. Panel (B) lists the optogenetic therapies that have been tested in ganglion cells (Bi et al., 2006; Lin et al., 2008; Zhang et al., 2009; Caporale et al., 2011; Tomita et al., 2014; Sengupta et al., 2016; Berry et al., 2017), while (C) lists those tested in bipolar cells (Lagali et al., 2008; Gaub et al., 2014, 2015; Macé et al., 2015; Scalabrino et al., 2015; van Wyk et al., 2015).