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Vision Prescription Converter

Transpose your eyeglasses prescription between plus and minus cylinder formats.

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Vision Prescription Converter

Transpose eye prescription

Complete Guide

Overview

Transpose your eyeglasses prescription between plus and minus cylinder formats. Use this calculator to get instant, accurate results based on standard health formulas and guidelines.

⚠️This tool is for educational and screening purposes only and is not a substitute for professional medical advice.

How to Use

1

Enter your details in the input fields above.

2

Select your preferred units (metric or imperial) if available.

3

Click the Calculate button to view your instant results and interpretation.

Formula & Calculation

Refer to the in-depth guide below for complete calculation formulas.

Benefits of Using This Calculator

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Accurate Results

Provides instant calculations for vision prescription converter.

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Clear Guidance

Compares your score against standard medical reference ranges.

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Fast & Free

No sign-up required — fast, private calculation on any device.

Pro Tips

  • Enter accurate measurements for the most reliable results.
  • Track your results over time to identify long-term trends.
  • Consult a qualified healthcare professional for medical interpretation.
In-Depth Guide

Vision Prescription Converter: Transpose Plus and Minus Cylinder

Eye prescriptions can be written in either Plus Cylinder (used by ophthalmologists) or Minus Cylinder (used by optometrists). This calculator transposes between the two formats so your prescription can be read by any lab or dispenser.

The Transposition Rules

  1. New Sphere = Old Sphere + Old Cylinder
  2. New Cylinder = − (Old Cylinder)
  3. New Axis = Old Axis ± 90° (If axis ≤ 90, add 90; if axis > 90, subtract 90)

Worked Example

Original: SPH −2.00, CYL −1.00, Axis 90
New SPH = −2.00 + (−1.00) = −3.00
New CYL = − (−1.00) = +1.00
New Axis = 90 + 90 = 180
Transposed: SPH −3.00, CYL +1.00, Axis 180

Transpose your prescription with our Vision Prescription Converter.