A free, simple, and easy to use app to calculate the Surgically Induced Astigmatism (SIA) or Surgically Induced Refractive Change (SIRC).
Just enter the keratometric values before and after the operation to get the refractive changes induced by the operation.
The app includes Vector analysis method which enables you to calculate the induced refractive change as a sphere and cylinder change.
The app also enables you to do Polar analysis to calculate the Polar values of the refractive change which determine the flattening or steepening effect with it's rotation according to a selected meridian.