Understanding CYL and AXIS Values in Contact Lens Prescriptions
CYL (Cylinder) and AXIS values are essential components of contact lens prescriptions for individuals with astigmatism. These parameters are used in toric lenses to correct the irregular curvature of the eye. Below, we provide a comprehensive guide to understanding when these values are required, what to do if they are unavailable, and how to ensure your prescription details are accurate.
When Are CYL and AXIS Values Required?
CYL and AXIS values are necessary for toric contact lenses, which are specifically designed to correct astigmatism. If your prescription includes these values, it indicates that you require lenses tailored to address this condition. Attempting to order spherical lenses (which do not include CYL and AXIS) for astigmatism correction will result in an incorrect fit and vision correction. If you choose spherical lenses despite having astigmatism, your vision may be blurry or uncomfortable.
Scenarios Where CYL and AXIS Are Not Required
If your prescription does not include CYL and AXIS values, it means you do not have astigmatism or that your astigmatism does not require correction with contact lenses. In such cases, you should order spherical lenses, which only require parameters like sphere power (SPH), base curve (BC), and diameter (DIA). Spherical lenses are designed to correct nearsightedness or farsightedness, which is why they do not include CYL and AXIS values.
What to Do When CYL and AXIS Values Are Unavailable
Unavailable Parameters from Suppliers
If a specific CYL or AXIS value is not available from the lens manufacturer, the order cannot be fulfilled as specified. It is possible you either have a prescription for glasses which cannot be used to purchase contacts or an incorrect value entered by the doctor. In such cases, you would need to contact the doctor and clarify which prescription they've provided you with and/or ask them to adjust the parameters on the prescription. Glasses prescriptions often include parameters that are not directly transferable to contact lenses. For example, glasses prescriptions may have CYL and AXIS values that need to be converted into standardized increments for contact lenses. Only a qualified eye care professional can perform this conversion.
Discontinued Parameters
In some cases, manufacturers may discontinue specific parameters, such as an axis of 60 (060) for certain powers. If this occurs, you will need to consult your eye care provider for alternative options or switch to a different lens brand. Additionally, some lens brands, such as KITS Daily Silicone Hydrogel and Air Optix plus HydraGlyde, are spherical lenses and do not support CYL and AXIS values, making them unsuitable for individuals with astigmatism.
Providing Accurate Prescription Details
To ensure your order is processed correctly, it is crucial to provide accurate prescription details. Here are some tips:
Submit a clear photo of your valid prescription that includes all necessary parameters, such as SPH, CYL, and AXIS.
Ensure that your prescription is specifically for contact lenses, as glasses prescriptions may not be directly transferable.
Verify that the prescription values are in standardized increments, such as SPH and CYL rounded to the nearest 0.25 diopters and AXIS values selected from standard options.
FAQs
What should I do if I ordered spherical lenses but have astigmatism?
If you have mistakenly ordered spherical lenses but your prescription includes CYL and AXIS values, you should exchange the unopened and unmarked boxes for toric lenses. Ensure you provide a valid contact lens prescription, including SPH, CYL, AXIS, and brand details, to facilitate the exchange.
Can I use my glasses prescription to order contact lenses?
No, glasses prescriptions are not directly transferable to contact lenses. Glasses prescriptions often include parameters that need to be converted into standardized increments for contact lenses by a qualified eye care professional.
Can I Use a Prescription with CYL and AXIS for Spherical Lenses?
No, spherical lenses are not designed to correct astigmatism and cannot accommodate CYL and AXIS values. If your prescription includes these parameters, you must order toric lenses.
Conclusion
Understanding CYL and AXIS values is essential for ordering the correct contact lenses. Always consult your eye care provider for guidance and ensure your prescription details are accurate to avoid delays or issues with your order. If you encounter unavailable parameters, explore alternative brands or adjustments with your provider. Additionally, check product specifications to ensure the lenses support astigmatism correction if required, and remember that unopened and unmarked lenses can often be exchanged for the correct prescription if needed.