Surface Power

This is the basic level of lens calculation technology that only considers a fixed, non-tilted lens, tangential rays, infinitely small pupil and replaces the eye by a constant remote sphere.


This method is based on a pure geometrical conception of the lens. It will provide the wearer with the prescribed power they need in the far, near and intermediate regions. But, unlike Digital Ray-Path®, no additional aberration compensation will be performed. The wearer will get a digital lens, but equivalent in terms of power computation to a conventional progressive. The Power and Addition. The Power and Addition are what we call Nominal, the Prescribed Power. This technology is used only in our Basic designs, and according to this, we recommend our customers to position the lenses produced with this technology in the basic segment of their product portfolio.


  • Easy to be understood by opticians
  • Easy to measure the power and compare to prescription with conventional means
  • Variable Inset: Automatic and manual
  • Freedom in base curve selection
  • Nice entry-level digital lens

Calculation technologies. summary