To figure GP (Oxygen Permeable) 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

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

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).

First K Reading Second K Reading

Output

Corneal Cylinder:

Adjustment factor:

Base Curve in Diopters:

Base Curve in Millimeters"

Diameter:

Optical Zone:

Bevel:

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).
First K Reading	Second K Reading

Output
Corneal Cylinder:
Adjustment factor:
Base Curve in Diopters:
Base Curve in Millimeters"
Diameter:
Optical Zone:
Bevel: