Contact Lens Vertex Calculator
Spectacle Rx (D)
Spherical power in diopters.
Please enter a valid number.
Vertex Distance (mm)
Distance from cornea to spectacle lens.
Please enter a number between 0 and 30.
Calculate
Contact Lens Rx:
D
Formula:
F_cl = F_spec / (1 - d * F_spec) where d = vertex distance in meters.
Step-by-step: