Niels Ryberg Finsen (1860–1904) developed a lamp based on electric carbon arcs (later known as the Finsen light) that was used for skin therapy a century ago. He became director of the Medical Light Institute in Copenhagen, later the Finsen Institute, where he developed this method of treatment. Within a few years, 40 Finsen Institutes were established in Europe and in the United States of America. In 1903, Finsen received the Nobel Prize in Medicine in recognition of his work on the treatment of diseases and, in particular, the treatment of lupus vulgaris by means of concentrated light rays. Finsen's scientific interests were greatly influenced by his health condition. Beginning in 1883, he began to experience symptoms of an illness that would be later diagnosed as Niemann-Pick disease. He spent the last years of his life confined to a wheelchair. Dermatology reaps the benefits of light treatment to this day.