Medical Disclaimer

What does this medical disclaimer cover?

This medical disclaimer covers every calculator and explainer on Contact Lens Calc.

Contact Lens Calc is manufacturer-agnostic. We convert spectacle prescription to contact lens parameters and show the optics. We do not write a contact lens prescription. Independent professional judgment still applies after the number appears.

The following five bounds apply site-wide:

• Starting parameters are trial and documentation values, not a contact lens prescription
• The site does not provide medical advice and does not create a doctor–patient relationship
• The site does not recommend a manufacturer SKU
• Base curve, diameter, and material are not produced by spectacle-power conversion
• A licensed eye-care practitioner still decides ordered power after on-eye fit and over-refraction

Those five bounds are the scope of this page. Calculators remain educational and informational. They are not for medical emergencies. Verify parameters against the written refraction, product labeling, and the on-eye finding before you order.

Why are starting contact lens parameters not a prescription?

Starting contact lens parameters are converted power at the corneal plane, not a US contact lens prescription.

A glasses Rx supplies sphere, cylinder, and axis at the spectacle plane. Conversion vertex-compensates that power as a starting point. A full contact lens prescription cannot be produced from glasses alone.

According to the FDA Buying Contact Lenses page, a valid US contact lens prescription includes fields a glasses conversion does not return:

• Power of the prescribed contact lenses
• Material and/or manufacturer
• Base curve, or an appropriate designation
• Diameter, when appropriate
• Issue of a prescription copy once the lens fitting is complete

Those fields come from an eye-health exam, keratometry or topography, a trial lens, and a licensed fitter. The clinical explainer of that split isStarting Contact Lens Parameters Are Not a Prescription.

Who decides ordered power after a starting calculation?

A licensed eye-care practitioner decides ordered power after on-eye fit and over-refraction.

Calculator output is a starting point for a diagnostic trial. According to the ODReference Contact Lens Conversion Calculator, that starting power is for ordering and documentation, then on-eye assessment and over-refraction. The CooperVision OptiExpert hub footnote states the calculators aid eye-care practitioners and are not a replacement for a professional contact lens fitting.

We disclose the method we use: default vertex 12 mm when unspecified, vertex by meridian when power is at or above about ±4.00 D, optional spherical equivalent only when a spherical lens is intended, and rounding to the nearest 0.25 D step. The formulas live onHow We Calculate. The fitter still confirms the lens on eye.

What do Contact Lens Calc calculators return?

Contact Lens Calc calculators return starting parameters, not a finished contact lens prescription.

The following three values make up that starting set:

• Sphere for each eye, stated at the corneal plane
• Cylinder and axis where toric correction stays indicated
• The vertex distance behind the numbers (12 mm when none is entered)

They are not four values a glasses Rx never contained:

• Base curve
• Diameter
• Material or manufacturer SKU
• An FTC contact lens prescription issued after a completed fitting

Vertex is applied by meridian for toric prescriptions, not to sphere only. Spherical equivalent equals Sphere + (Cylinder ÷ 2) after vertex. That equivalent is not a substitute for indicated toric correction. The Contact Lens Conversion Calculator returns those starting optical values.

Convert this spectacle Rx to starting contact lens parameters.

How should patients use Contact Lens Calc?

Patients use Contact Lens Calc to understand starting parameters, not to order contact lenses.

According to the FDA Contact Lenses consumer page, you can buy contact lenses only if you have a current, valid prescription. According to the same agency’s Buying Contact Lenses page, the FTC Contact Lens Rule requires eye-care providers to give customers copies of their contact lens prescriptions once the lens fitting is complete.

Educated-patient copy explains why glasses numbers differ from contact lens numbers. It does not invite self-prescribing.

How do independent calculators treat starting power?

Independent and manufacturer calculators treat converted power as a starting point or an educational aid, not as a finished prescription.

The following four peer bounds match that pattern. We describe them. We do not copy their legal text.

• ODReference labels conversion output a starting point for ordering and documentation, then on-eye assessment and over-refraction. Its medical disclaimer states content is educational, is not medical advice, and does not create a doctor–patient relationship.
• CooperVision’s tools footnote states the calculators aid eye-care practitioners and are not a replacement for a professional contact lens fitting.
• Johnson & Johnson’s simplifit disclaimer states the calculator is for educational and convenience purposes and is not a substitute for independent professional judgment. That page also states J&J does not prescribe and cannot warrant accuracy or completeness.
• Omni Calculator’s terms state calculators are informational and supportive, and that a professional verifies each result before use. Its vertex tool page does not carry an equivalent starting-point bound.

We agree on the bound. We add the manufacturer-agnostic wording those brand tools omit: starting contact lens parameters still require an on-eye fit. We do not adopt Omni’s “fit you” framing. We do not warrant that a calculated starting power is complete for every eye or a standard of care.

Where do fitting, methodology, and conversion live?

Fitting, methodology, and conversion live on their own URLs so this disclaimer stays the site-wide bound.

The following three pages complete convert, calculate, fit, and verify:

• Conversion calculator — convert spectacle prescription to contact lens parameters
• How we calculate — vertex formula, 12 mm default, ±4.00 D gate, and 0.25 D rounding
• Fitting explainer — starting contact lens parameters are not a prescription

Convert a spectacle prescription to contact lens parameters first. Then read the method. Then treat the number as a trial starting point until a licensed practitioner fits and verifies it on eye. Contact lens parameters at the corneal plane remain starting parameters until that fitting is complete.

Utility: How we calculate · Medical disclaimer