A technology for inhibition of myopia progression adapted to the RPR of the wearer is provided. A spectacle lens and related technology are provided that include a base area that causes a beam that enters through an object-side surface to exit through an eye-side surface and converge on a retina via the eye, and a plurality of defocus areas that each contact the base area and have a characteristic whereby a beam that passes through at least a portion of the defocus area is incident on the retina as a diverging ray, and, in not less than half of the plurality of defocus areas, at least one of a defocus power and a size of each defocus area is set, so as to compensate for a change in retinal spot size due to relative peripheral refraction (RPR) that depends on an eccentricity angle of the eye of the wearer.