Prism prescription value acquisition system, acquisition method, acquisition apparatus and program for correcting fixation disparity

Patent metadata

Field	Value
Publication number	US-9492075-B2
Application number	US-201414761668-A
Country	US
Kind code	B2
Filing date	Jan 20, 2014
Priority date	Jan 18, 2013
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

A prism prescription value acquisition system that includes a calculation part for numerically transforming a fixation disparity amount (unit: angle), which indicates a degree at which the visual axis is shifted from the central fovea of the retina when a subject conducts visual fixation of a target, into a prism prescription value by multiplying the fixation disparity amount by a coefficient when the fixation disparity amount is within ±4 minutes. Herein, the prism prescription value is calculated according to the following equation: AP ver =k ver *FD ver , AP hor =k hor *FD hor providing that each of coefficients k hor and k ver satisfies the following conditions: 0.3≦k ver ≦0.7, 1.4≦k hor ≦2.0.

First claim

The invention claimed is:

1. A prism prescription value acquisition system comprising:
a calculation part for numerically transforming a fixation disparity amount (unit: angle), which indicates a degree at which a visual axis is shifted from the central fovea of the retina when a subject conducts visual fixation of a target, into a prism prescription value by multiplying the fixation disparity amount by a coefficient when the fixation disparity amount is within ±4 minutes;
Herein, the prism prescription value is calculated according to the following equation:
AP ver =k ver *FD ver
AP hor =k hor *FD hor

AP ver represents a prism amount (unit: prism diopter) in a vertical direction (top and bottom direction) in the prism prescription value,
AP hor represents a prism amount in a horizontal direction in the prism prescription value, and
FD ver represents a fixation disparity amount in a vertical direction;
FD hor represents a fixation disparity amount in a horizontal direction,
providing that each of coefficients k hor and k ver satisfies the following conditions:
0.3≦ k ver ≦0.7

1.4≦ k hor ≦2.0.

2. A prism prescription value acquisition system according to claim 1 , further comprising a judgment part for judging whether a fixation disparity amount is within ±4 minutes or not, wherein
when said judgment part judges that the fixation disparity amount is within ±4 minutes, said calculation part numerically transforms the fixation disparity amount into a prism prescription value.

3. A prism prescription value acquisition system according to claim 2 , further comprising:
a measuring part for measuring a fixation disparity amount, and
a transmission part for transmitting the fixation disparity amount measured by said measuring part to said calculation part;
said measuring part comprising
a display means for displaying, after setting a direction of fixation disparity, a visual target for the right eye presented only to the right eye, a visual target for the left eye presented only to the left eye, and a visual target for visual fixation for which a subject conducts visual fixation, and
an input means for flexibly moving at least either the visual target for the right eye or the visual target for the left eye displayed on said display means, wherein
when the visual target for the right eye or the visual target for the left eye is moved, the visual target for visual fixation is not moved, and in a state in which a subject continuously conducts visual fixation of the visual target for visual fixation, a fixation disparity amount is measured from a shift amount of the two visual targets on said display means.

4. A prism prescription value acquisition system according to claim 3 , wherein
the visual target for the right eye (presented only to the right eye), the visual target for the left eye presented only to the left eye, and the visual target for visual fixation for which a subject conducts visual fixation displayed on said display means are included in one test figure, and
said test figure can be flexibly placed at any location at a front of a background image provided with a plurality of visual targets for visual fixation.

5. A prism prescription value acquisition system according to claim 4 , wherein
said display means is a stereoscopic image display means capable of presenting different images to the right eye and the left eye separately; the visual target for the right eye is presented to the subject's right eye and the visual target for the left eye is presented to the subject's left eye.

6. A prism prescription value acquisition system according to claim 3 , wherein
said display means is a stereoscopic image display means capable of presenting different images to the right eye and the left eye separately; the visual target for the right eye is presented to the subject's right eye and the visual target for the left eye is presented to the subject's left eye.

7. A prism prescription value acquisition system according to claim 1 , further comprising:
a measuring part for measuring a fixation disparity amount, and
a transmission part for transmitting the fixation disparity amount measured by said measuring part to said calculation part;
said measuring part comprising
a display means for displaying, after setting a direction of fixation disparity, a visual target for the right eye presented only to the right eye, a visual target for the left eye presented only to the left eye, and a visual target for visual fixation for which a subject conducts visual fixation, and
an input means for flexibly moving at least either the visual target for the right eye or the visual target for the left eye displayed on said display means, wherein
when the visual target for the right eye or the visual target for the left eye is moved, the visual target for visual fixation is not moved, and in a state in which a subject continuously conducts visual fixation of the visual target for visual fixation, a fixation disparity amount is measured from a shift amount of the two visual targets on said display means.

8. A prism prescription value acquisition system according to claim 7 , wherein
the visual target for the right eye (presented only to the right eye), the visual target for the left eye presented only to the left eye, and the visual target for visual fixation for which a subject conducts visual fixation displayed on said display means are included in one test figure, and
said test figure can be flexibly placed at any location at a front of a background image provided with a plurality of visual targets for visual fixation.

9. A prism prescription value acquisition system according to claim 8 , wherein
said display means is a stereoscopic image display means capable of presenting different images to the right eye and the left eye separately; the visual target for the right eye is presented to the subject's right eye and the visual target for the left eye is presented to the subject's left eye.

10. A prism prescription value acquisition system according to claim 7 , wherein
said display means is a stereoscopic image display means capable of presenting different images to the right eye and the left eye separately; the visual target for the right eye is presented to the subject's right eye and the visual target for the left eye is presented to the subject's left eye.

11. A prism prescription value acquisition method for numerically transforming a fixation disparity amount (unit: angle), which indicates a degree at which a visual axis is shifted from the central fovea of the retina when a subject conducts visual fixation of a target, into a prism prescription value by multiplying the fixation disparity amount by a coefficient when the fixation disparity amount is within ±4 minutes;
Herein, the prism prescription value is calculated according to the following equation:
AP ver =k ver *FD ver
AP hor =k hor *FD hor

AP ver represents a prism amount (unit: prism diopter) in a vertical direction (top and bottom direction) in the prism prescription value,
AP hor represents a prism amount in a horizontal direction in the prism prescription value, and
FD ver represents a fixation disparity amount in a vertical direction;
FD hor represents a fixation disparity amount in a horizontal direction,
providing that each of coefficients k hor and k ver satisfies the following conditions:
0.3≦ k ver ≦0.7

1.4≦ k hor ≦2.0.

12. A prism prescription value acquisition method according to claim 11 , wherein
whether a fixation disparity amount obtained by measurement A of th

Assignees

• Hoya Corp

Inventors

• Schroth Volkhard
• Jaschinski Wolfgang
• Warntjes Hans
• Hatanaka Takashi

Classifications

• A61B3/0025

  characterised by electronic signal processing, e.g. eye models · CPC title

• A61B3/0091

  Fixation targets for viewing direction · CPC title

• A61B3/085 Primary

  for testing strabismus · CPC title

• A61B3/08 Primary

  for testing binocular or stereoscopic vision, e.g. strabismus · CPC title