How to Read Astigmatism Chart Measurements

With the emergence of various electronic devices, the most significant issue affecting today’s youth is declining vision—commonly known as myopia. Most individuals with myopia also experience astigmatism. So, how do you read the degree of astigmatism from an astigmatism chart?

How to Read Astigmatism Degree from an Astigmatism Chart

Astigmatism degree is determined through a refractive examination conducted at a hospital. If you receive a glasses prescription, it will list values for the left eye (OS), right eye (OD), and spherical lens power—the latter indicating the degree of myopia or hyperopia. Another key value listed is the cylindrical lens power (cylinder), which quantifies the amount of astigmatism. Since astigmatism has directional properties, its axis—the orientation of the steepest corneal curvature—is indicated in degrees (e.g., 180°, 135°, or 90°) immediately following the cylinder value on the prescription.

In cases of astigmatism, severity must be assessed based on the specific degree. Patients with astigmatism exceeding 150 diopters typically experience pronounced subjective symptoms—including double vision (diplopia), reduced visual acuity, and eye fatigue when not wearing corrective lenses. Irregular astigmatism tends to cause more severe visual disturbances than regular astigmatism, necessitating correction. Common treatment options include wearing eyeglasses or contact lenses, or undergoing refractive surgery. For high-degree astigmatism, implantation of a toric intraocular lens may be considered.

It is recommended to regularly perform eye exercises in daily life. After surgery, avoid eye strain and limit screen time on electronic devices.