Optician more important and dignified. Far-sighted or aging colonial Americans imported spectacles from Europe. Spectacles were primarily for the affluent and literate colonists, who required a valuable and precious appliance. Benjamin Franklin in the 1780s developed the bifocal. Bifocal lenses advanced little in the first half of the 19th century. The terms bifocal and trifocal were introduced in London by John Isaac Hawkins, whose trifocals were patented in 1827. In 1884 B. M. Hanna was granted patents on two forms of bifocals which become commercially standardized as the "cemented" and "perfection" bifocals. Both had the serious faults of ugly appearance, fragility,
Spectacles (product) Spectacles (product) Spectacles are pairs of smartglasses dedicated to recording video for the Snapchat service. They feature a camera lens and are capable of recording short video segments and syncing with a smartphone to upload to the user's online account. They were developed and manufactured by Snap Inc., announced on September 23, 2016, during Snap Inc's rebrand from Snapchat Inc. and released on November 10. They are made for Snap's image messaging and multimedia platform Snapchat and were initially distributed exclusively through Snap's pop-up vending machine, Snapbot. On February 20, 2017, Snap Spectacles became available for purchase online. On April