S and C stand for spherical lenses and astigmatism, respectively. The normal standard for spherical lenses changes as children age, while the normal standard for astigmatism is zero.
The normal standard for astigmatism is 0. Spherical lenses are also referred to as myopia or hyperopia, and are usually labeled with + for hyperopia and – for myopia. The standard value of spherical lenses is related to age. Newborns can have 500-600 degrees of hyperopia due to their short eye axes, and as they grow older, their eye axes gradually become longer and the degree of hyperopia decreases.
Under normal circumstances, 3-year-old children can have about 300 degrees of hyperopia, 8-year-old children are usually within 150 degrees of hyperopia, and children who have reached the age of 12 are usually within 50 degrees of hyperopia, which tends to be 0 degrees.
Astigmatism is the basis for determining whether a patient has astigmatism or not, and is usually indicated by + for hyperopic astigmatism and – for myopic astigmatism. The normal standard for astigmatism is 0. If the test result is not 0, the patient has astigmatism.
It is recommended that patients with refractive abnormalities seek prompt medical attention to evaluate their condition and follow the doctor’s instructions for treatment.