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Rx Transposition Calculator
Convert between plus and minus cylinder instantly
Enter Original Prescription
Try These Examples
The Transposition Formula
1
Add Sphere + Cylinder
Algebraically add the original sphere and cylinder to get the new sphere.
New SPH = SPH + CYL
2
Flip Cylinder Sign
Change the cylinder from plus to minus, or from minus to plus.
New CYL = -CYL
3
Rotate Axis 90°
Add or subtract 90° from the axis (keep between 1° and 180°).
New AXIS = AXIS ± 90°
Frequently Asked Questions
Transposition is the process of converting an eyeglass prescription from plus cylinder format to minus cylinder format, or vice versa. Both formats describe the exact same prescription - they're just written differently. The optical power and correction are identical.
