Looking at your eye prescription, it can seem like a jumble of confusing numbers and terms.
Understanding what these mean isn’t exactly necessary, but it’d nice to at least have an idea of what’s going on with your precious peppers.
One term you may notice on your eye report is “axis,” which plays a crucial role in correcting certain vision issues. In this article, I'll simply break down what axis means on your eye test results and what it means for your visual correction.
Let’s dive in.
What does Axis mean on your eye prescription?
Axis is a number that indicates the orientation (angle) of astigmatism in your eye which is measured in degrees. Astigmatism occurs when the cornea (the front part of your eye) is slightly irregular in shape, meaning it isn't perfectly round. This irregular shape causes light to focus unevenly on your retina, leading to blurry or distorted vision.
The angle of axis tells the lens maker the exact direction along which to correct this astigmatism. In short, it shows where on the eye the cylindrical power should be applied to allow for clear vision. Without the correct axis, your glasses won't properly align with your eye's shape, and your vision could remain blurred.
How is the Axis Measured?
The axis measurement is expressed in degrees, ranging from 0 to 180. This describes the orientation of the astigmatism on a flat plane. For example, if the axis is 90 degrees, the cylindrical correction would be vertically aligned, while an axis of 180 degrees be horizontally aligned.
Your optometrist determines this value during an eye test using specific equipment designed to asses astigmatism and its orientation. The axis helps ensure that your prescription lenses are accurately aligned with the irregular curve of your cornea.
How the Axis Impacts Your Glasses Lenses
If you have an axis measurement on your prescription, it means your lenses will be customised to correct astigmatism. The axis helps position the cylindrical correction in the right place to ensure clear vision. For people with astigmatism, this precision is key to making sure that light properly focuses on the retina.
If the axis is even slightly off, the lenses won’t function as intended, and you could still experience blurriness or discomfort when wearing your glasses. This is why it’s essential to have an accurate prescription from your optometrist.
How does Axis relate to your CYL?
An eye prescription includes several other components alongside the axis, particularly Sphere (SPH) and Cylinder (CYL).
Sphere (SPH) corrects short-sightedness or long-sightedness.
Cylinder (CYL) is specifically for correcting astigmatism, indicating the strength of the lens needed to correct the irregular curvature of the eye.
The axis, in combination with the cylinder, ensures that your lenses are shaped and oriented correctly for your individual vision needs. For example, a prescription might look something like this:
- SPH: -2.00
- CYL: -1.25
- Axis: 100
In this example, the sphere corrects for short-sightedness, the cylinder indicates the degree of astigmatism, and the axis shows how to correct that cylindrical deformity.
FAQs about Axis in eye prescriptions
Can the axis number change over time?
Yes, your axis measurement can change over time, particularly if your astigmatism shifts or your cornea changes shape. Regular eye tests will ensure that your prescription stays accurate.
What happens if my glasses’ axis is incorrect?
If the axis is incorrect, the lenses won’t properly correct your vision. This can result in ongoing blurred vision, discomfort, or even headaches. It’s important to have your prescription checked if you’re experiencing these issues.
Can I wear contact lenses with an axis prescription?
Yes, contact lenses can be made to correct astigmatism. These are known as toric lenses, and they work in a similar way to glasses lenses, with the cylinder and axis providing the necessary correction.
What axis should my eyes be?
There isn’t a specific axis number that your eyes “should” be. The axis is a unique measurement for each person’s astigmatism, ranging from 0 to 180 degrees. It represents the orientation of your astigmatism rather than a “good” or “bad” number. Your optometrist will determine the exact axis that works for your eyes during your eye test.
Is an axis of 180 good or bad?
An axis of 180 is neither inherently good nor bad. It simply means that the astigmatism correction is applied horizontally along the 180-degree line. The key is that the axis is accurate for your eyes, regardless of the specific number.
Can my eye axis be 0?
Yes, an axis can be 0 degrees. This just means that the astigmatism correction is applied along the 0-degree (or horizontal) axis. Like with any other axis number, it’s not a sign of good or bad vision but a measurement specific to the orientation of your astigmatism.
Hopefully, you found this article helpful. Please check out our other eyecare blogs. Thanks for stopping by.