The refractive index of current eyeglass lens materials ranges from 1.498 (CR-39 plastic) to 1.74 (a specific variety of high-index plastic). So for the same prescription power and lens design, a lens made of CR-39 plastic will be the thickest lens available, and a 1.74 high-index plastic lens will be the thinnest.
Principal photography on the film began on April 25, 2016, in Pittsburgh, Pennsylvania, in the Hill District, and wrapped in mid-June 2016. Fences was released in the United States on December 16, 2016, by Paramount Pictures, received positive reviews and grossed $64 million.
Updated September 17, 2016. Arguably August Wilson's most renowned work, Fences explores the life and relationships of the Maxson family. This moving drama was written in 1983 and earned Wilson his first Pulitzer Prize. Fences is part of August Wilson's Pittsburg Cycle, a collection of ten plays.