Retinal S antigen refers to a protein found in the retina, which plays a crucial role in visual perception. Synonyms for this term include retinal pigment epithelium-specific protein, RPE65, and retinal-specific antigen. Retinal pigment epithelium-specific protein serves as a vital component in the visual cycle, aiding in the regeneration of rhodopsin and maintaining optimal vision. RPE65 deficiency is associated with certain retinal dystrophies, highlighting the significance of this antigen. Additionally, the term RPE65 is frequently used in scientific research and clinical trials, where potential therapies for retinal diseases are being explored. These synonyms contribute to a deeper understanding of retinal S antigen and its implications in vision and ocular health.