What does “astigmatism axis” mean?
Jun 29, 2022
Source: Cainiu Health
Dr. Chen You
Introduction
Astigmatic axis refers to the optical axis of astigmatism, measured in degrees from 0° to 180°. An unfilled (i.e., unspecified or undefined) axis indicates the absence of astigmatism. The axial orientation of a pair of toric lenses is critically important; incorrect alignment can compromise visual quality and wearing comfort. Axial orientation applies only to regular astigmatism. Astigmatism is classified into three types: with-the-rule, against-the-rule, and oblique. With-the-rule astigmatism is defined as having its steepest meridian within ±30° of 90°.
Many people visit ophthalmology clinics for eye examinations when they notice declining vision, blurred images, or double shadows. At this point, they are often diagnosed with astigmatism. However, even after receiving a diagnosis, many patients remain unclear about what astigmatism actually means. So, what is “astigmatism axis”?
What does “astigmatism axis” mean?
The astigmatism axis refers to the optical axis of astigmatism, measured in degrees from 0° to 180°. An unfilled (i.e., unspecified) axis value indicates no astigmatism. The axial orientation of a pair of toric lenses is critically important—incorrect alignment can significantly impair visual quality and comfort. Axial orientation applies only to regular astigmatism. Astigmatism is classified into three types: with-the-rule (WTR), against-the-rule (ATR), and oblique astigmatism. WTR astigmatism occurs when the meridian of maximum refractive power lies within ±30° of the 90° meridian.
Preventing prolonged eye use helps reduce the risk of developing astigmatism. Whether reading or using a smartphone, avoid continuous visual tasks for more than one hour. After an hour, take a break or perform eye exercises. These practices help relax the ciliary muscles, lower intraocular pressure, and prevent astigmatism and other refractive errors. Maintaining proper posture during work is also an effective preventive measure: while working, keep your gaze level or slightly downward toward the screen to minimize the exposed surface area of the eyes.
A balanced diet supports ocular health by ensuring adequate and well-rounded nutrition for the eyes, thereby helping to prevent vision impairment. We hope this explanation has been helpful.
