The term "175 axis" is typically used in the context of ophthalmology and optometry, particularly relating to eyeglasses or contact lenses prescriptions. The "axis" refers to the orientation of astigmatism measured in degrees.
Key Components of Prescription
- Sphere (SPH): This indicates the degree of nearsightedness or farsightedness.
- Cylinder (CYL): This measures the astigmatism, or the irregular curvature of the cornea or lens.
- Axis: This denotes the orientation of the astigmatism in degrees, ranging from 1 to 180.
175 Axis Explained
- Orientation: An axis of 175 degrees means that the cylindrical correction for astigmatism is oriented slightly counterclockwise from the horizontal line, which is considered 0 degrees.
- Measurement: The axis measures the specific angle at which astigmatism is present. In this case, an axis of 175 degrees indicates that the patient’s astigmatism is aligned on the 175-degree meridian.
Importance of Axis
- The correct axis is crucial for effective vision correction. If the axis is misaligned, it can result in blurred vision, discomfort, or headaches.
- In practice, it is essential for the lens manufacturer to fabricate the lenses with precision according to the specified axis to ensure optimal visual correction.
Summary
In summary, "175 axis" specifically refers to the angular measurement for correcting astigmatism in an eyeglass or contact lens prescription. It is a critical component of the prescription that helps ensure that the lenses effectively correct the wearer’s vision. If someone has a prescription with a "175 axis," it indicates the particular orientation for the astigmatic correction, which must be accurately reflected in any lenses made for that individual.