PWR=power of eyes prescription, If your eyesight is normal or you only need decoration, please choose -0.00. Consulting your ophthalmologist to confirm diopter before ordering. DIA=diameter of the whole lens VISUAL DIA= lens inner diameter for sight, normal inner dia is 3.8~4.2mm, small pupil inner dia is 2.5mm, vision will be slightly affected/blurry due to this (tunnel vision)