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A plus-cylinder prescription is one of two different ways to write the instructions for making a lens that corrects astigmatism. In this form, the number in the "Cylinder" (CYL) column of the prescription always has a plus sign (+) in front of it. While it may look different, it can describe the exact same lens as a minus-cylinder prescription.
read more about plus cylinder prescription form ...Think of it like saying "twelve" versus "a dozen." They are two different ways to describe the same number. In optics, a prescription for astigmatism can be written in a plus-cylinder or minus-cylinder form. An ophthalmologist (a medical eye doctor) often uses the plus-cylinder form, while an optometrist or optician more commonly uses the minus-cylinder form. Both are correct.
Transposition is the simple, three-step process of converting a prescription from one form to the other. An optician will often transpose a plus-cylinder prescription into a minus-cylinder one before ordering your lenses. This is done to maintain a consistent standard in the lab. When this is done, all three numbers in your prescription (sphere, cylinder, and axis) will change, but the final lens that is made will be exactly the same.
For you as the wearer, it does not matter at all. The glasses you receive will be correct no matter which form the doctor used to write the prescription. It is simply a difference in professional notation, much like two scientists using different but equally valid formulas to describe the same thing. The minus-cylinder form has become the most common standard for optical labs today.
To understand the difference between plus and minus cylinder forms, eye doctors use a diagram called an "optical cross." This diagram draws the two principal powers of the eye at 90-degree angles. The plus-cylinder form builds the prescription by starting at the most nearsighted point and adding plus power. The minus-cylinder form starts at the most farsighted point and subtracts minus power. Both paths arrive at the exact same final destination for your vision.
Yes, it is perfectly fine and correct. The optical shop will know exactly what to do with it and how to make your lenses accurately.
This is a very common sign that your prescription was transposed. When you convert from plus- to minus-cylinder form, the axis always changes by 90 degrees. This is normal and correct.
Yes. After transposition, the sphere power will change, the cylinder sign will flip, and the axis will change by 90. It will look like a completely different prescription, but it makes the identical lens.
You typically do not need to worry about which form your prescription is written in. However, if you are comparing two of your prescriptions and are confused because all the numbers have changed, you can ask your optician. They can show you how one was transposed from the other and confirm that the correction is the same.
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Astigmatic Refractive Error Types of Astigmatism and Clinical Implications. American Academy of Ophthalmology. https://www.aao.org/Assets/3d714124-a292-4e27-b12f-c762885ce9f5/637151349599870000/bo14-pdf?inline=1. Accessed April 7, 2026.
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