The term "cyl" refers to cylinder, which is part of an eyeglasses prescription used to correct astigmatism. Having a "cyl" value in your prescription is not considered abnormal; rather, it indicates that you have astigmatism.
Understanding Astigmatism
Astigmatism is a common vision condition where the eye's cornea or lens isn't perfectly round, but more oval-shaped. This causes light to bend unevenly, resulting in blurry or distorted vision at all distances.
How Cylinder (CYL) Corrects Astigmatism
- Cylinder: This number in your prescription shows the degree of astigmatism you have. It is always associated with an axis number.
- Axis: This number represents the orientation of the astigmatism on your eye. It specifies the meridian or direction in which your astigmatism is located.
Example Prescription:
| Sphere (SPH) | Cylinder (CYL) | Axis |
|---|---|---|
| -1.00 | -0.50 | 180 |
In this example:
- -1.00 represents the spherical correction for nearsightedness.
- -0.50 represents the astigmatism correction.
- 180 represents the direction of astigmatism correction.
Is Having a CYL Normal?
It's important to understand that:
- Having a CYL value is very common: Many people have some degree of astigmatism.
- It is not a disease or a sign of eye problems: It is simply a common visual condition that can be easily corrected with glasses or contact lenses.
- The need for a CYL correction may change: Astigmatism can change over time, so regular eye exams are crucial to ensure your prescription is accurate.
So, if your eye exam results in a CYL value, it means you have astigmatism, but this is not considered "abnormal". It's a common refractive error. It is the correction for the astigmatism that is included on your prescription.
