Measuring method for measuring sensing capability of eye of subject, and setting method for progressive power lens

A designing method for a progressive power lens suitable for an eye of a subject, the progressive power lens having regions of a distance vision part for distance viewing, a near vision part for near viewing, and an intermediate vision part positioned between the distance vision part and the near vision part, the progressive power lens changing in refractive power between the distance vision part and the near vision part, the designing method comprising:

• showing an image of a predetermined pattern on a display screen, the display screen being shown in front of an eyeball of the subject by a display device that is secured to a head of the subject;
• showing a fixation target to be focused on by the subject, on the display screen, in order to make a line of sight of the subject be a certain line of sight;
• showing a change region where the image of the predetermined pattern is changed, the change region being separated from an intersection point and the fixation target, the intersection point being where the line of sight directed downward of the subject focusing on the fixation target, crosses the display screen;
• showing the change region, where the image of the predetermined pattern is changed, on the display screen, in such a manner that the change region is continuously or intermittently brought close to or away from the intersection point or the fixation target in the display screen;
• determining a range in which the subject can sense the change region, in response to the change region shown by bringing the change region close to or away from the intersection point or the fixation target, whereby the sensitivity of the eye is measured;
• and
• designing a refractive power distribution suitable for the subject on a basis of information of the measured sensitivity of the eye, wherein
• the fixation target is shown overlapping a part of the image of the pattern on the display screen,
• the certain line of sight is a first line of sight, the first line of sight being made when the fixation target is shown at a first position on the display screen,
• a second line of sight is made when the fixation target is shown at a second position on the display screen, the second line of sight being in a direction different from a direction of the first line of sight,
• the first position on the display screen is located at a center of the display screen such that the first line of sight corresponds to the subject looking straight ahead,
• the method further includes showing the fixation target at the second position, and
• the method further comprises:
• performing a first measurement by showing the fixation target at a first position on the display screen and determining a first range in which the subject can sense the change region;
• and
• performing a second measurement by showing the fixation target at a second position on the display screen, different from the first position, and determining a second range in which the subject can sense the change region.