





INSTRUCTIONS

A good approximation of the First Choice Base Curve for
KeraSoft THIN
can be calculated using the Tangential map on a topography machine. For best results, use a Normalized

map with 5mm zone included and numerical values displayed. (For more information, go to the
Using Tangential Topography
page.)


Once you have the map, insert the steepest and flattest central Sim Ks into the calculator and then the steepest and flattest Sim Ks on the 5 mm ring and click "Calculate".


The optimal correction factor results are highlighted in orange and the calculator gives the base curve to select based on whether this is a central or low cone.


This calculation does NOT work with the Axial (Sagittal) maps, as the mid periphery values are different, nor does it work with surgically changed corneas, as the natural relationship

between areas of the cornea has been altered.
