Lens Exchange

Question: We have your software and use it as our primary calculator for iol power calculations. I need to perform a lens exchange for an unexpected outcome. I am unclear how to use your Holladay R calculator. Do you have any instructions for how to calculate the replacement lens for an IOL exchange?


  1. All you need to do is change the REFRACTION on the PREOP SCREEN to the CURRENT REFRACTIVE SURPRISE.
  2. Then CLICK IOL CALC and change the FORMULA to Holladay R (REFRACTIVE).
  3. The displayed powers are what must be added (or subtracted) from the CURRENT IOL to achieve the DESIRED REFRACTION. Example: If current IOL is 20.0 D and the Holladay R shows -3.5 D for the Desired Refraction, then 20.0 – 3.5 = 16.5 D IOL for the exchange. The -3.5 D is also the power of the Secondary Piggy Back for reference.