Downward Eyeball Movement Measuring Jig, Jig Affixing Device, and Downward Eyeball Movement Measuring Method

1 . downward eyeball movement measuring jig which measures downward eyeball movement corresponding to a distance between a distant eye point and a near eye point of a spectacle lens attached to a spectacle frame to be worn by a wearer of the spectacle lens, comprising:

a mask which is provided on the surface of an examination spectacle lens attached to the spectacle frame and has a reference line passing the distant eye point and extending in the horizontal direction.

2 . The downward eyeball movement measuring jig according to claim 1 , wherein:

the mask has a width corresponding to the expected length of the downward eyeball movement of the wearer and two opposed sides; and

the reference line corresponds to one of the two opposed sides of the mask.

3 . The downward eyeball movement measuring jig according to claim 1 , wherein:

the mask has two opposed sides; and

the reference line is disposed at a position away from the two opposed sides.

4 . The downward eyeball movement measuring jig according to claim 2 , wherein:

the other side of the two opposed sides of the mask is disposed directed to the near eye point; and

the mask is a tape-shaped mask which has a tape base, and an adhesive portion disposed on the side of the tape base facing the examination spectacle lens and detachably affixed to the examination spectacle lens.

5 . The downward eyeball movement measuring jig according to claim 2 , wherein:

the mask has a plurality of lines provided on the surface of the examination spectacle lens in an area expected to contain the near eye point in such directions parallel with the reference line; and

the mask is a tape-shaped mask which has a tape base, and an adhesive portion disposed on the side of the tape base facing the examination spectacle lens and detachably affixed to the examination spectacle lens.

6 . The downward eyeball movement measuring jig according to claim 5 , wherein the plural lines have colors different from one another.

7 . A jig affixing device which affixes the downward eyeball movement measuring jig according to claim 4 to an examination spectacle lens, comprising:

a spectacle hold unit which holds spectacles having the examination spectacle lens attached to a spectacle frame; and

a tape supply unit which supplies the tape-shaped mask to the spectacles held by the spectacle hold unit,

wherein

the spectacle hold unit has a base opposed to the examination spectacle lens, and a frame support member attached to the base in such a condition as to be movable in a direction perpendicular to a horizontal vision area passing an eye point of the examination spectacle lens and extending in the horizontal direction to support the spectacle frame, and

the tape supply unit has a cutter member which cuts the tape-shaped mask, and a lens affixing member which transfers the tape-shaped mask cut by the cutter member to the spectacles held by the spectacle hold unit and affixes the tape-shaped mask such that one of the sides of the tape-shaped mask can be aligned with the horizontal vision area.

8 . The downward eyeball movement measuring jig according to claim 4 , wherein an end of the tape-shaped mask is formed by folding the adhesive portion such that the folded parts of the adhesive portion can be stacked with each other.

9 . The jig affixing device according to claim 7 , wherein the cutter member has a fold forming portion which folds the end of the tape-shaped mask.

10 . A method for measuring downward eyeball movement corresponding to a distance between a distant eye point and a near eye point of a spectacle lens attached to a spectacle frame to be worn by a wearer of the spectacle lens, comprising:

preparing a tape-shaped mask which has a width corresponding to the expected length of the downward eyeball movement of the wearer for the surface of an examination spectacle lens attached to the spectacle frame, positioning the tape-shaped mask such that one of two opposed sides of the tape-shaped mask passes the distant eye point of the examination spectacle lens, and affixing the tape-shaped mask to the examination spectacle lens with the other side of the tape-shaped mask located close to the near eye point of the examination spectacle lens; and

determining whether the near eye point of the examination spectacle lens agrees with the other side of the tape-shaped mask, and the determination is made by the wearer wearing spectacles which has the examination spectacle lens attached to the spectacle frame with the tape-shaped mask affixed to the examination spectacle lens,

wherein

when it is determined that the near eye point does not agree with the other side of the tape-shaped mask, determination is repeated after removing the tape-shaped mask from the examination spectacle lens and affixing another tape-shaped mask having a different width.