Near or far sighted. Sphere is the degree of near (minus power) or far (plus power) sightedness. For example, -3.00 sphere is 3 diopters of nearsightedness. -4.00 would be even more nearsightedness. Put a + in front of those numbers instead, and that would be farsightedness. Sphere does not include any astigmatism, a.K.A. Cylinder.