Our recent findings in the transgenic PD mice model (M83 expressing human A53 T variant α-synuclein) showed that there was a significantly thinner OPL and ONL, which correlated with the pathological α-synuclein accumulation in the ONL [139] Similarly, in Xu et al.’s study [73], the phosphorylated Ser129 α-synuclein accumulation was detected in the OPL of the same mouse model (M83), along with the degeneration of photoreceptor cells, including the loss of photoreceptor terminals in the OPL, and attenuated outer retinal photoreceptor function. Here, SNCA is linked to Parkinson disease.