In a retinitis pigmentosa model, the 23H-1 rat, photoreceptor degeneration starts at the beginning of light responsiveness; Cer, S1P and SM increase in the retina early during degeneration, with a reduction in shorter-chain species and an increase in longer-chain species (Stiles et al., 2016). This evidence concerns the gene CBLN1 and retinitis pigmentosa.