Santen Pharmaceutical Co., Ltd., is a Japanese pharmaceutical company, specializing in ophthalmology. With its ophthalmic products Santen holds the top share within the Japanese market and is one of the leading ophthalmic companies worldwide, with its products being sold in over 50 countries. The company was founded in 1890 by Kenkichi Taguchi, as Taguchi Santendo, and in 1925, Santendo Co., Ltd. was established. In 2014 Santen announced that it has entered into an agreement with Merck & Co. to purchase Merck's ophthalmology products. Wikipedia