A negative sign is used to indicate degrees of myopia, and a positive sign is used to indicate farsightedness. Under normal circumstances, 100 degrees of myopia is negative 1.0D, D is myopia, 1.0 is 100 degrees of myopia, 100 degrees is 1.0D. If there is a negative 0.75D, it means that the degree of myopia is 75, if there is a negative sign, it means that it is myopia, if there is a positive sign, it means that it is the diopter of farsightedness. However, if a small child affects the visual acuity to 0.8 or less, it is usually still recommended to wear myopic glasses, which will be detrimental to the growth of myopia even more.