More recently, Luhmann et al reported that when mice were housed under dim conditions (33 lux light intensity), none of the genetically modified mice, including CCL2 KO, CX3CR1 KO and CCL2/CX3CR1 DKO developed retinal degeneration by the age of 12–14 months [34]. This evidence concerns the gene CX3CR1 and retinal degeneration.