Knowing the effect of frame fit, or Position of Wear (PoW) measurements, in compensated freeform lenses is key for today’s optician. While PoW measurements improve overall lens performance in freeform compensated lenses, the lensometer reading will appear to fall outside of ANSI tolerances relative to the original Rx. The compensated power of the lens as received from the lab is not varying from the original Rx, but instead produces the effective power to achieve the original Rx in an as-worn lens. This is an important concept that remains a mystery for many ECPs. Read on to learn why compensated lenses are checked against the lab verification values and not against the original Rx. Read More