Gene therapy for color blindness near 530 nm, and the S cone absorbs near 420 nm. Contrary to popular belief, the peak absorption frequency for L, M, and S cones do not exactly correspond to red, green, and blue wavelength. Rather, the peak frequency for the L cone is orange, yellowish green in M cones, and blue-violet in S cones. These cones transduce the absorbed light into electrical information to be relayed to neurons in the retina such as retinal bipolar cells and retinal ganglion cells, before reaching the brain. The signals from different cones are added or subtracted from each other to process the
Intrinsically photosensitive retinal ganglion cells able to isomerize "all-trans-"retinal into "11-cis-"retinal when stimulated with light without help from additional cells. The two isoforms of melanopsin differ in their spectral sensitivity, for the "11-cis"-retinal isoform is more responsive to shorter wavelengths of light, while the "all-trans" isoform is more responsive to longer wavelengths of light. ipRGCs are both pre- and postsynaptic to dopaminergic amacrine cells (DA cells) via reciprocal synapses, with ipRGCs sending excitatory signals to the DA cells and the DA cells sending inhibitory signals to the ipRGCs. These inhibitory signals are mediated through GABA which is co-released from the DA cells along with dopamine.