Acts as a calcium sensor and regulates phototransduction of cone and rod photoreceptor cells (By similarity). Modulates light sensitivity of cone photoreceptor in dark and dim conditions (By similarity). In response to high Ca(2+) levels induced by low light levels, prolongs RHO/rhodopsin activation in rod photoreceptor cells by binding to and inhibiting GRK1-mediated phosphorylation of RHO/rhodopsin (By similarity). Plays a role in scotopic vision/enhances vision in dim light by enhancing signal transfer between rod photoreceptors and rod bipolar cells (By similarity). Improves rod photoreceptor sensitivity in dim light and mediates response of rod photoreceptors to facilitate detection of change and motion in bright light (By similarity). Homodimer; disulfide-linked (By similarity). Homodimerization is caused by prolonged intense illumination (By similarity). May form a complex composed of RHO, GRK1 and RCVRN in a Ca(2+)-dependent manner; RCVRN prevents the interaction between GRK1 and RHO (By similarity). Interacts (via C-terminus) with GRK1 (via N-terminus); the interaction is Ca(2+)-dependent (By similarity). Primarily expressed in the inner segments of light-adapted rod photoreceptors, approximately 10% of which translocates from photoreceptor outer segments upon light stimulation (By similarity). Targeting of myristoylated protein to rod photoreceptor outer segments is calcium dependent (By similarity). EF-hand 2 and EF-hand 3 domains are the low-affinity and the high-affinity calcium binding sites, respectively. EF-hand 1 and EF-hand 4 domains do not bind calcium due to substitutions that disrupt their respective Ca(2+) binding loops. The cooperative binding of calcium to the EF-hand 2 domain following EF-hand 3 domain calcium binding requires myristoylation (By similarity). Calcium binding to the 2 EF-hand domains induces exposure of the myristoyl group through a protein conformation change, this process known as the calcium-myristoyl switch facilitates binding to photoreceptor cell membranes (By similarity). The N-terminal glycine is linked to one of four different types of acyl groups. The most abundant is myristoleate (14:1), but 14:0, 14:2, and 12:0 acyl residues are also present (By similarity). The Ca(2+) induced exposure of the myristoyl group, known as the calcium-myristoyl switch, promotes RCVRN binding to the photoreceptor cell membranes only when intracellular Ca(2+) concentration is high (By similarity). Oxidation on Cys-39 occurs in response to prolonged intense illumination and results in the formation of disulfide homodimers, and to a lesser extent disulfide-linked heterodimers. Belongs to the recoverin family.