How to read an eyeglass prescription: Understanding myopia and astigmatism values
Oct 26, 2023
Source: Cainiu Health
Dr. Wang Shuai
Introduction
In general, to determine the degree of myopia and astigmatism, you should look at the values corresponding to the letters A and C on the eyeglass prescription. A stands for the spherical lens (sphere), and this value indicates whether the patient is nearsighted or farsighted: a "+" sign indicates farsightedness, while a "-" sign indicates nearsightedness. For example, -2.00 means 200 degrees of myopia, and -1.75 means 175 degrees of myopia.
Generally, the degree of myopia and astigmatism can be determined by checking the values corresponding to the letters "A" and "C" on a prescription eyeglass or optometry report. The specific analysis is as follows:
"A" stands for the spherical lens (sphere), which indicates whether the patient has myopia (nearsightedness) or hyperopia (farsightedness). A "+" sign indicates hyperopia, while a "-" sign indicates myopia. For example, -2.00 means 200 degrees of myopia, and -1.75 means 175 degrees of myopia. "C" stands for the cylindrical lens (cylinder), and this value represents the degree of astigmatism. For instance, -0.5 indicates 50 degrees of astigmatism, and -1.0 indicates 100 degrees of astigmatism.
In most cases, astigmatism often accompanies myopia. This combination can affect vision, causing double images and eye fatigue. Further refraction testing is required, and wearing properly prescribed glasses is necessary for correction. Contact lenses may also be used for correction, and in special cases, surgical correction might need to be considered.
