OptiDex — Professional Optical Toolbox

Vertex Distance Conversion

Convert spectacle Rx to contact lens plane (or any target vertex distance). Updates live as you type.

Input Rx & Vertex

Sphere (D)

Cylinder (D)

Spectacle Vertex Distance (mm)

Target Vertex Distance (mm) — use 0 for contact lens

Result

New Sphere

—

New Cylinder

—

Spherical Equivalent

—

at the target plane

Enter values above — results update live.

F' = F / (1 − d·F) | d = vertex shift in meters
Applied independently to sphere & sphere+cyl meridians

Prentice's Rule Calculator

Calculate induced prismatic effect at any point on a lens. Updates live as you type.

Parameters

Lens Power (D)

Decentration (mm)

Direction of Decentration

Eye

Result

Prismatic Effect

—

Base direction: —

Enter values above — results update live.

Δ = P × c | P = power (D), c = decentration (cm)
Base direction follows standard ophthalmic convention

Lens Thickness Calculator

Frame-based edge thickness at nasal, temporal, superior, and inferior edges — accounts for cylinder axis and OC placement.

Prescription

Sphere (D)

Cylinder (D)

Axis (°)

Refractive Index

Center Thickness CT (mm)

Base Curve

Base Curve (D)

AUTO

Edit to override. Change sphere to restore auto.

Frame — Boxing System

Eye Size A (mm)

Bridge (mm)

B-dimension (mm)

PD & OC Placement

Mono PD (mm)

OC Height from bottom (mm)

Eye

Edge Thickness at Frame

—

Sup

—

Inf

—

Nas

—

Tem

Nasal

—

Temporal

—

Superior

—

Inferior

—

H-Decentration

—

OC Vertical Offset

—

Values update live as you type.

r=(n−1)/F×1000mm | sag=y²/(2r) | ET=CT+sag_back−sag_front | F(θ)=Fsph+Fcyl·sin²(θ−axis)

Contact Lens Database

100+ lenses including private labels. Click any row to expand full parameter details, axis charts, and store brand equivalents.

Brand	Type	BC / Diam	Power Range