Apparatus for measuring downward rotation amount of eyeball and method for measuring downward rotation amount of eyeball

1. An apparatus for measuring a downward rotation amount of eyeball that measures a length from a distance-vision eye point to a near-vision eye point of a spectacle lens actually worn by a wearer and attached to a frame having an upper side portion and a lower side portion, comprising:

a line-of-sight position detecting unit that detects a position of a line of sight corresponding to the distance-vision eye point of the wearer and a position of a line of sight corresponding to the near-vision eye point; and

a computing unit that computes a distance between the position of the distance-vision eye point and the position of the near-vision eye point detected by the line-of-sight position detecting unit, wherein

the line-of-sight position detecting unit has an arm member that is rotatable at one end and positioned at a lateral position of an eyeball of the wearer, a front detecting mechanism that is disposed on the other end side of the arm member and detects a front position of the eyeball of the wearer, and an arm rotation angle detecting unit that detects a rotation angle of the arm member.

2. The apparatus for measuring the downward rotation amount of eyeball according to claim 1 , wherein

the arm member is rotatably supported to an arm supporting member at the one end side, and the arm supporting member is rotatably attached to a supporting column.

3. The apparatus for measuring the downward rotation amount of eyeball according to claim 2 , wherein

the arm supporting member can expand and contract.

4. The apparatus for measuring the downward rotation amount of eyeball according to claim 3 , further comprising wearer chairs each arranged on opposite sides of the supporting column, wherein

the arm supporting member is rotatable at its distal end side so as to be positioned on opposite sides of the supporting column.

5. The apparatus for measuring the downward rotation amount of eyeball according to claim 1 , wherein

the front detecting mechanism is a camera.

6. A method for measuring a downward rotation amount of eyeball using the apparatus for measuring the downward rotation amount of eyeball according to claim 1 , comprising:

causing the wearer to face forward in a state of wearing the spectacle lens and determining a position of the spectacle lens corresponding to the pupil of the wearer as a distance-vision eye point line;

positioning the rotatable one end of the arm member at the lateral position of the eyeball of the wearer;

detecting, by the front detecting mechanism, that the pupil of the wearer is positioned on the distance-vision eye point line at the front and detecting, by the arm rotation angle detecting unit, an inclination angle of the arm member at this front position as a first angle;

detecting, by the front detecting mechanism, that the pupil of the wearer is positioned at the near-vision eye point at the front in a state where the wearer lowers his/her line of sight and detecting, by the arm rotation angle detecting unit, an inclination angle of the arm member at this position as a second angle; and

calculating, by the computing unit, a distance between the position of the distance-vision eye point and the position of the near-vision eye point based on a downward rotation angle of eyeball determined from a difference between the inclination angle detected in the detecting the first angle and the inclination angle detected in the detecting the second angle.

7. A method for measuring a downward rotation amount of eyeball using the apparatus for measuring the downward rotation amount of eyeball according to claim 1 , comprising:

causing the wearer to face forward in a state of wearing the spectacle lens and determining a position of the spectacle lens corresponding to the pupil of the wearer as a distance-vision eye point line;

positioning the rotatable one end of the arm member at the lateral position of the eyeball of the wearer;

detecting, by the front detecting mechanism, that the pupil of the wearer is positioned at the near-vision eye point at the front in a state where the wearer lowers his/her line of sight and detecting, by the arm rotation angle detecting unit, an inclination angle of the arm member at this position as a first angle;

detecting, by the front detecting mechanism, that the pupil of the wearer is positioned on the distance-vision eye point line at the front in a state where the wearer raises his/her line of sight and detecting, by the arm rotation angle detecting unit, an inclination angle of the arm member at this front position as a second angle; and

calculating, by the computing unit, a distance between the position of the distance-vision eye point and the position of the near-vision eye point based on a downward rotation angle of eyeball determined from a difference between the inclination angle detected in the detecting the first angle and the inclination angle detected in the detecting the second angle.