OPN4 and retinitis pigmentosa 1: We investigated another autosomal recessive RP mouse model caused by a missense mutation in the Pde6b gene (Pde6bH620Q/H620Q) [34], an autosomal dominant RP mouse model caused by a mutation in the rhodopsin gene (RhoP23H/+) [35], and Cnga3−/−, Rho−/−, Opn4−/− triple-knockout mice [36, 37].