Spectacle lens and method for designing same

A spectacle lens, comprising:

• a base region where a light flux incident from an object-side surface is emitted from an eyeball-side surface and converges on a retina through an eyeball;
• and
• a plurality of defocus regions surrounded by the base region and having a property that the light flux passing through at least a part of the defocus region is incident on the retina as a divergent light,
• the defocus region including a defocus region a provided at a predetermined position A and a defocus region b provided at a predetermined position B on a spectacle lens,
• wherein when a direction toward outside of a lens, which is a normal direction on a base surface, is shown by a positive sag value, and a direction toward inside of the lens, which is a normal direction on the base surface, is shown by a negative sag value, with the base surface of the base region as a reference, a sag value of a 3D shape of the defocus region b is a value in which a sag value of a 3D shape of the defocus region a is increased,
• wherein at least center points of the defocus region a and the defocus region b are in an appearance of a curved shape protruding toward outside of the lens, and
• wherein a radius of curvature at the center point of the defocus region a is equal to a radius of curvature at the center point of the defocus region b.