Rod-specific cGMP phosphodiesterase that catalyzes the hydrolysis of 3',5'-cyclic GMP (PubMed:20940301). Necessary for the formation of a functional phosphodiesterase holoenzyme (By similarity). Involved in retinal circadian rhythm photoentrainment via modulation of UVA and orange light-induced phase-shift of the retina clock (By similarity). May participate in processes of transmission and amplification of the visual signal (PubMed:8394174). 3',5'-cyclic GMP + H2O = GMP + H(+) Binds 2 divalent metal cations per subunit. Site 1 may preferentially bind zinc ions, while site 2 has a preference for magnesium and/or manganese ions. Oligomer composed of two catalytic chains (alpha and beta), an inhibitory chain (gamma) and the delta chain. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Belongs to the cyclic nucleotide phosphodiesterase family. Retina International's Scientific Newsletter