Glasses-lens assessment method, glasses-lens design method using assessment method, and calculation method for visual-performance characteristics of test subject when viewing object through lens

The invention provides an evaluation method capable of objectively evaluating average visual perception for a comparatively long period of time when a subject looks through an eyeglass lens to be evaluated, time-dependent change in visual perception, and visual perception when looking with both eyes, and the invention provides a design method, and the invention provides a calculation method for calculating characteristics of visual perception of the subject when viewing an object through a lens. [Solution] A subject is allowed to wear a lens to be evaluated, the subject is allowed to induce brain activity by allowing the subject to view a changing visual stimulus object that induces periodic brain activity through the lens to be evaluated, a change in faint electric current caused by the brain activity is time-dependently recorded as a change in a magnetic field (magnetic flux density) by use of a magnetoencephalograph, one or more among an amplitude, a power value, and a phase in a frequency that is an inverse number of a period of the periodic brain activity is or are calculated through fast Fourier analysis of the waveform, and the lens to be evaluated and the characteristic of visual perception of the subject are evaluated based on a magnitude of an amplitude or of a power value obtained above or based on a slowness/fastness of a phase obtained above.