Lenses

Optical vertex conversion

Soft Toric Contact Lens to Glasses Power Estimator

Enter the PWR, CYL, AX, BC, and DIA values exactly as printed on a soft toric contact-lens package.

This is not a glasses prescription. A contact lens prescription may omit refractive details and cannot replace an eye exam or spectacle refraction.

Package type comfilcon A · soft toric Designed for the information shown in the supplied package image.

Spectacle vertex distance mm

BC and DIA describe contact-lens fit. They are retained with the entered package information but do not affect the spectacle vertex-power calculation.

Lens 1

Which eye? PWR Sphere CYL Cylinder AX Axis ° BC Base curve mm DIA Diameter mm

Lens 2

Which eye? PWR Sphere CYL Cylinder AX Axis ° BC Base curve mm DIA Diameter mm

I understand this result is an optical estimate and must not be used to order glasses without professional verification.

Method, limitations, and references

Each principal meridian is converted independently using Fspectacle = Fcontact / (1 + d × Fcontact), where d is the vertex distance in metres. The two converted meridians are then recombined into sphere and cylinder. The displayed axis is unchanged by vertex conversion alone.

The rounded result rounds both converted principal meridians to the nearest 0.25 D before recombination. The unrounded result is included for auditability.

This version is specifically limited to single-vision soft toric package values. It does not support multifocal or monovision designs, RGP, scleral, hybrid, or orthokeratology lenses; prism; toric rotation compensation; accommodation; frame tilt or wrap; and any missing astigmatism.

Lenses

Results

Lens 1

Lens 2