Modern day Bi focals

In 1780, Benjamin Franklin invented bi focal glasses. These are my fancy varifocal version. Not easy to take a blip without wearing them! My choice is a bit rushed as we have spent the day travelling and are finally enjoying a glass of wine on our Tenerife balcony. 
Thanks to Laurie54 for hosting what is going to be an interesting mono Monday month with today's subject relating to an 18th century invention.