When you receive your eyeglass prescription, you may notice a number in the “Axis” column, such as 175. This number is crucial for correcting astigmatism. Understanding what the 175 axis eye meaning is can help you better comprehend your vision needs and how your glasses work. This article will break down the significance of an axis of 175 degrees, its role in vision correction, and what it means for your overall eye health.
What Does the Axis Number Mean in an Eyeglass Prescription?
The axis is a number between 1 and 180 that describes the orientation of astigmatism correction in your eyeglass lenses. Astigmatism occurs when the cornea (the clear front surface of the eye) or the lens inside the eye has an irregular shape, more like a football than a basketball. This irregularity causes light to focus on multiple points in the eye, leading to blurry or distorted vision at all distances.
The axis number tells your optician where to place the cylindrical power (the astigmatism correction) in the lens. It is measured in degrees, similar to a compass. A 175 axis is very close to horizontal, specifically just 5 degrees off from the 180-degree horizontal meridian.
How the 175 Axis Relates to Astigmatism
An axis of 175 degrees indicates that the steepest curve of your cornea is oriented nearly horizontally. This means your astigmatism correction needs to be aligned along this near-horizontal axis to properly focus light onto your retina. The cylinder power (e.g., -1.00 or +2.00) works in conjunction with the axis to neutralize the irregular curvature.
For example, a prescription might read: -2.00 -1.00 x 175. This means you have 2.00 diopters of nearsightedness (myopia), 1.00 diopter of astigmatism, and the astigmatism correction is oriented at 175 degrees.
Is a 175 Axis Common?
Yes, a 175 axis is relatively common. Most people with astigmatism have an axis between 90 and 180 degrees, which is known as “with-the-rule” astigmatism. In this type, the vertical meridian of the eye is steeper than the horizontal meridian. Since 175 is near horizontal, it falls into this common category. Conversely, “against-the-rule” astigmatism has an axis between 1 and 90 degrees, which is less common but still normal.
What Does a 175 Axis Mean for Your Vision?
If you have a 175 axis, your vision is likely blurry or distorted without correction, especially for fine details. You may experience:
- Blurred vision at all distances (near and far)
- Difficulty seeing at night, especially with glare from headlights
- Eye strain, headaches, or squinting
- Distorted shapes (e.g., seeing a circle as an oval)
With proper correction using glasses or contact lenses, these symptoms are effectively eliminated. The 175 axis value itself does not indicate a problem; it is simply a measurement of the orientation of your astigmatism.
How to Read Your Prescription with a 175 Axis
Your eyeglass prescription will have several numbers. Here is how to interpret them:
- Sphere (SPH): This indicates nearsightedness (-) or farsightedness (+).
- Cylinder (CYL): This is the amount of astigmatism correction needed. If this is blank or 0.00, you have no astigmatism.
- Axis: This is the orientation of the cylinder correction, ranging from 1 to 180. A 175 axis means the correction is placed nearly horizontally.
For example: OD: -1.50 -0.75 x 175, OS: -1.25 -0.50 x 005. The right eye (OD) has a 175 axis, while the left eye (OS) has a 005 axis (very close to horizontal but on the opposite side).
Does the 175 Axis Change Over Time?
In most people, the axis of astigmatism can change slightly over time, especially during childhood or as you age. However, a change of 5-10 degrees is not uncommon and is usually not a cause for concern. Significant shifts (e.g., from 175 to 90) may indicate changes in corneal shape due to conditions like keratoconus or after eye surgery. If you notice a large change in your axis, consult your eye doctor.
Treatment Options for Astigmatism with a 175 Axis
Astigmatism with a 175 axis is easily correctable. Standard options include:
- Eyeglasses: The most common and effective solution. Lenses are precisely ground to match your prescription, including the 175 axis.
- Contact Lenses: Toric contact lenses are designed to stay in place and correct astigmatism. They have a specific axis orientation that aligns with your eye.
- Refractive Surgery: LASIK, PRK, or SMILE can reshape the cornea to correct astigmatism. The surgeon uses advanced mapping to treat the irregular curvature, including the 175 axis orientation.
When to See an Eye Doctor
If you experience sudden changes in vision, double vision, or eye pain, schedule an eye exam immediately. For routine care, adults should have a comprehensive eye exam every 1-2 years. During the exam, your doctor will measure your axis and update your prescription as needed.
Frequently Asked Questions About the 175 Axis
Is a 175 axis bad?
No, a 175 axis is not bad. It is simply a measurement of the orientation of your astigmatism. It does not indicate poor eye health or a serious condition.
Can I have a 175 axis in one eye and a different axis in the other?
Yes, it is very common for each eye to have a different axis. For example, one eye might be 175 and the other 005. This is normal and your prescription will account for both.
Does the 175 axis affect my ability to wear contact lenses?
No, but you will need toric contact lenses designed for astigmatism. These lenses have a weighted design to keep them stable and aligned with your 175 axis. Your eye doctor will fit you with the correct type.
Conclusion
The 175 axis eye meaning is straightforward: it is the orientation of your astigmatism correction, measured at 175 degrees, which is nearly horizontal. This is a common and normal finding in eyeglass prescriptions. With proper correction, you can achieve clear, comfortable vision. Always follow your eye doctor’s recommendations and schedule regular eye exams to maintain optimal eye health.