Marco Polo, an Italian trader and traveler, reported that he saw people wearing glasses in China in about 1275.  Although no one knows when or where people wore glasses first, Europeans probably started wearing glasses in the 1200’s.  In 1784, Ben Franklin invented bifocals.  Bifocals have two-part lenses, one part for reading and the other part for seeing far away.  Glasses today have single focus, bifocal, or trifocal lenses.  A single focus lens has one focal point like the first glasses found in China.  A bifocal lens has two focal points, one for distance and one for reading like the glasses Ben Franklin invented.  Today there are also trifocal lenses that add a third focal point for middle distance vision.  Glasses have really improved over the years.  They have become different sizes, better prescriptions, and they look better on people.