Equivalent spherical lenses are the final lenses calculated by combining all refractive errors such as astigmatism. Equivalent spherical lenses are used clinically as the primary basis for screening and determining myopia. Equivalent spherical lenses convert a patient’s astigmatism into a spherical lens with similar optical effects to represent the refractive state of the eye, which is expressed as half of the spherical lens plus half of the prismatic lens. Equivalent spherical lenses are generally composed of concave lenses, convex lenses, and cylindrical lenses, and are used to correct refractive errors such as nearsightedness or farsightedness in patients. It is recommended that patients with refractive errors seek prompt medical attention to evaluate their condition and follow the doctor’s instructions for the appropriate treatment modality.