Every eyeglass prescription is consisted of numbers describing the refractive abnormality for each eye separately.

The first number is called the sphere and, if negative, refers to myopia and, if positive, to hyperopia. The + sign is always marked and
should not be omitted if the number is positive. The second number is called cylinder and refers to the diopters of astigmatism. The number of the cylinder can be positive or negative.

The third number is the axis of astigmatism and is measured in degrees. The symbol «x» is usually inserted between degrees and the degrees of astigmatism.