👉 The term "diopter" is a measurement unit in optical instruments and devices. It refers to the ratio of the distance from the center of a lens or screen to the focus point on the eye that is needed for a particular object to be clearly seen. The diopter was first introduced by Sir Isaac Newton (1642-1727) in his work "Philosophiæ Naturalis Principia Mathematica" in 1687. The term "diopter
