As cone-specific cGMP phosphodiesterase, it plays an essential role in light detection and cone phototransduction by rapidly decreasing intracellular levels of cGMP. {ECO:0000269|PubMed:21127010, ECO:0000269|PubMed:28583373}. This is the function of Ensembl gene identifier ENSG00000095464 (PDE6C, phosphodiesterase 6C).