Transitions Optical was founded in 1990. In 1991, Transitions Optical became the first company to commercialize and manufacture plastic photochromic lenses. From inception the company has been a joint venture between PPG Industries (51%) and Essilor (49%). In April 2014, Essilor acquired the 51% stake of PPG in Transitions.Transitions lenses are also called adaptive lenses. They are clear indoors and at night and automatically darken outdoors as light conditions change.