What Is Axis in Glasses Prescription
What Is Axis in Glasses Prescription?
When you go for an eye exam and receive a glasses prescription, you may notice a term called “axis” mentioned alongside other numbers and abbreviations. The axis is a crucial component of your prescription, particularly for those diagnosed with astigmatism. Understanding what the axis represents and its significance in your glasses prescription is essential for obtaining the correct eyewear.
The axis is a measurement of the orientation or angle of astigmatism in your eyes. Astigmatism occurs when the cornea (the clear front surface of the eye) or the lens inside the eye has an irregular shape, resulting in blurred or distorted vision. It causes light to focus on multiple points rather than a single point on the retina. The axis value in your prescription determines the location of the lens’s cylindrical power needed to correct this irregularity.
The axis is expressed in degrees ranging from 1 to 180 and is typically written in increments of 10. It indicates the angle at which the cylindrical correction should be placed in your eyeglasses. The axis is specific to each eye and may differ between the left and right eye.
11 FAQs about Axis in Glasses Prescription:
1. What does a zero axis mean in a glasses prescription?
A zero axis signifies that you do not have astigmatism and therefore do not require a cylindrical correction for your lenses.
2. How is the axis determined during an eye exam?
The axis is determined by the optometrist or ophthalmologist through a series of tests, such as retinoscopy or a subjective refraction, to assess the astigmatism in your eyes.
3. Can the axis value be the same for both eyes?
Yes, it is possible to have the same axis value for both eyes, but it is more common for them to be different.
4. What happens if the axis is written as 180 degrees?
An axis value of 180 degrees means that the astigmatism is horizontal, aligned with the 9 and 3 o’clock positions, and requires a specific correction to address this orientation.
5. Can the axis value change over time?
The axis value can change over time due to various factors, such as aging or the progression of an eye condition. Regular eye exams are crucial to detect any changes in your prescription.
6. How does the axis affect the lens design?
The axis determines the placement of the cylindrical correction on your lenses, ensuring that it aligns with the astigmatism orientation for optimal vision correction.
7. What if the axis value is not mentioned in my prescription?
If the axis value is not present, it means you do not have astigmatism or it is so minimal that it does not require correction.
8. Can I determine the axis value by myself?
No, determining the axis value requires specialized equipment and expertise, so it can only be accurately assessed by an eye care professional.
9. Can a higher or lower axis value affect my vision?
Yes, an incorrect axis value can result in distorted or blurred vision. It is crucial to have the correct axis value in your glasses prescription for optimal visual clarity.
10. Does the axis value affect the appearance of my glasses?
No, the axis value does not affect the appearance of your glasses. It is an internal measurement used by the optician to craft your lenses accurately.
11. Can contact lenses have an axis value?
Yes, contact lenses for astigmatism also have an axis value. It is important to consult with your eye care professional to ensure the correct axis is prescribed for your contact lenses.
Understanding the axis in your glasses prescription is essential for obtaining the correct lenses to address astigmatism. Ensure you visit an eye care professional regularly to assess any changes in your prescription and maintain optimal vision correction.