Our eyewear measurements consist of three numbers. The first number – the eye size – represents the horizontal width of one lens. The second number – the nose bridge size – is the distance between the lenses, which also is the size of the “bridge” of the frame that rests on your nose. The last number – the temple length – is the length from the connection point of the frames and the arm down to the piece that sits behind your ear. These sizes are based in millimeters and can be used to determine the best eyewear style for you.