Santen Pharmaceutical Co Ltd is a drug manufacturing company that focuses on ophthalmic products. The company reports two primary operating segments: prescription ophthalmic pharmaceuticals and other. The pharmaceuticals segment includes over-the-counter pharmaceuticals, while the other segment includes medical devices. The vast majority of Santen's revenue is derived from its prescription ophthalmic pharmaceuticals segment, which manufactures and distributes prescription and OTC pharmaceuticals. Most of Santen's sales are generated in Japan, followed by other Asian countries.