To figure base curves subtract the smallest of the K readings from the largest (to find the corneal cylinder). Locate the adjustment factor according to the chart.

Corneal Cylinder Flatten by
0 - .50 .50
.62 - 1.25 .25
1.37 - 3.00 On flat "K"
Over 3.00 Consider Toric

Flatten the smallest K reading by the adjustment factor (subtract). Then convert from diopters to millimeters.

Example: 45.00/46.00
46.00-45.00=1.00
Flatten by .25 according to the chart.
45.00-.25=44.75
44.75=7.54mm
RGP Prescription
Enter the K's below, hit the Calculate button and the chart will do the math. Be sure to use the decimal point (44.00).
K Readings:
 
Prescription:

Base Curve Calculation Output


Power Calculation Output
  X

If the design requires a toric please call 1-800-223-1858 for expert consultation.