Cyl, or cylinder, in an eye prescription represents the amount of astigmatism present in your vision.
Understanding Astigmatism and Cyl
Astigmatism is a common vision condition that occurs when the cornea or lens of the eye is not perfectly spherical. Instead, it's more oval-shaped, like a rugby ball rather than a football. This irregular shape causes light to focus at multiple points instead of a single point on the retina, leading to blurry or distorted vision at all distances. Here's a breakdown:
- Cause: The eye is not perfectly round but rather shaped like a rugby ball.
- Effect: Light is not focused properly on the retina.
- Result: Both near and far vision is blurred or distorted.
How Cyl is Represented in Your Prescription
The "cyl" value in your prescription indicates the degree of astigmatism you have, usually measured in diopters. A higher number indicates a greater degree of astigmatism.
For example:
- A value of -1.00 indicates a mild amount of astigmatism.
- A value of -3.00 indicates a higher degree of astigmatism.
Additional Information About Astigmatism and Cyl
Along with the cyl value, your prescription also includes an axis value. This indicates the direction of the astigmatism, or the orientation of the oval shape of your eye. The axis is typically measured in degrees from 1 to 180. These two values work together to correct the astigmatism.
- Axis: The direction of astigmatism correction.
- Combination: Cyl and axis together correct the shape of the eye.
Practical Considerations
If you have astigmatism, your glasses or contact lenses will be made with a cylindrical lens that corrects the shape of your eye and allows light to focus correctly on the retina.
- Correction: Lenses use the cylindrical value to correct astigmatism.
- Improved Vision: Corrected vision provides sharper focus at all distances.
