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.
Release. In July 2014, it was announced that the film would be released on August 21, 2015. In May 2015, the film's release date was moved to June 3, 2016. In November 2015, the film's release date was moved back, to March 4, 2016, before being delayed again in January 2016, to its previous June 3, 2016 release date. Reception