An Introduction to Trifocal Sunglasses
Trifocal and bifocal sunglasses are both kinds of multi-focal sunglasses, which is a combination of both sunglasses and multi-focal eyeglasses. However, trifocal sunglasses are an extension of bifocal ones, since bifocal sunglasses have two focus points while trifocals have three,… Read moreAn Introduction to Trifocal Sunglasses