Have you operated a lens meter before?
This simulation works like a physical lens meter. The power drum and axis dial make the target lines come into focus.
The lines in the target will be clearest when the drum reaches the actual power of the eyewear, and when the axis setting reaches the prescribed value.
Users can compare their measurements against the prescription shown.
Computer users: click and drag with your mouse.
iPad users: touch and drag with a stylus or your hand.