The Cylinder (CYL) measurement on your prescription indicates the amount of astigmatism present in your eye. Astigmatism is a common and very correctable condition caused by an irregular curve in the cornea or lens, and the Cylinder value tells us how much correction is needed to bring your vision into clear focus. Not everyone will have a Cylinder value on their prescription.
Understanding the value
The presence of a Cylinder value simply means that some astigmatism has been measured in that eye. It always works together with another measurement called the Axis.
- The Cylinder shows the strength of astigmatism correction needed
- It may be written as a positive or a negative number
- It works alongside the Axis to position the correction accurately
How we can help
During your eye examination we measure your Cylinder value carefully so that your lenses correct any astigmatism accurately and comfortably. We are always happy to explain what each part of your prescription means in plain, friendly terms, so you feel fully informed about your own vision.
If you have questions about your prescription, or feel your vision has changed, we warmly invite you to book a comprehensive eye examination with our practice.