On an eye prescription, “DS” typically stands for “diopters sphere.” This value indicates the amount of correction needed for nearsightedness (myopia) or farsightedness (hyperopia). A positive number preceded by “DS” indicates farsightedness, while a negative number indicates nearsightedness. For example, “DS +2.00” signifies a prescription for farsightedness requiring a correction of 2.00 diopters, while “DS -1.50” signifies a prescription for nearsightedness needing a correction of 1.50 diopters. The sphere value corrects the overall focus power of the eye.
The sphere correction is fundamental for clear vision, as it directly addresses the refractive error preventing light from focusing correctly on the retina. Accurate determination of this value is crucial for prescribing eyeglasses or contact lenses that provide optimal visual acuity. Historically, the measurement of refractive error has evolved from subjective testing methods to sophisticated automated instruments, improving the precision and efficiency of vision correction.