There is a difference between contact lenses and frames, mainly because myopic contact lenses need to subtract a certain number of diopters from the number of frames, while hyperopic contact lenses need to add a certain number of diopters to the number of frames. Usually more common in daily life, there are contact lenses and frame glasses, the degree of its prescription will have a certain difference, and the higher the degree of the eyes, the difference will be more obvious, and there are related formulas for calculation, such as contact lenses refractive error = frame glasses refractive error ÷ (1 – 0.012 × frame glasses refractive error). According to this formula, if the prescription of the glasses does not exceed 400 degrees, the difference is small and basically negligible. If the difference is large after exceeding 400 degrees, patients usually need to add or subtract degrees on the basis of frame glasses, such as contact lenses used to correct myopia, the degree is lower than that of frame glasses. It is recommended that patients in need of prescription lenses should visit the doctor in time to assess their condition and get prescription lenses under the doctor’s guidance to correct their vision.