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.
The film was first released on VHS and Laserdisc on October 25, 1990. On April 28, 2009, it was released on DVD - in the United States and re-released to DVD (in new packaging art) on September 8, 2015 and was aired in its original aspect ratio on Universal HD on February 2, 2007. The film is also available via digital download on the Sony Entertainment Network and the iTunes Store.