Contact Lens Calculator

Calculate contact lens parameters from your patient's spectacle prescription and Keratometry readings. Take into account vertex distance, the distance between the spectacle and the eye, approximately between 12 and 14 mm.

Enter parameters:

K1

K2

Corneal Astigmatism

Horizontal Visible Iris Diameter mm
We recomend TD 2.5 mm bigger than HVID

Spectacle prescription:

Sphere Cylinder Axis Addition

Vertex distance

Patient's keratometry (K) reading can be measured in Dioptres or milimeters This converter allows you to calculate both values.

Introduce one value to convert into dioptres to milimeters:

Corneal Power

dioptres

Corneal radius

mm

Over-refraction calculation indicates the requirec power for a soft toric CL given the power of the soft toric lens on the eye and the over-refraction.
The over-refraction calculator principally provides information relevant to changes in a lens' axis.
Results should be considered from an optometric view point.

Enter the data:

Soft toric contact lens rx:
Sphere
Cylinder
x
Axis
SB-Rx:
Sphere
Cylinder
x
Axis

New parameters specification:

Sphere
Cylinder
x
Axis