Visual Target Display Device for Cone-Specific Color Vision Testing
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Solution Overview
Problem
Current methods for testing color-related visual functions, such as those involving cone cells, lack precision in distinguishing between normal and abnormal color perception and the degree of color vision deficiency, particularly in differentiating between cone-specific visual functions.
Innovation Solution
A visual target display device and method that uses a chromatic visual target with a background of similar brightness, within ±10%, and colors in a relationship of confusion colors in dichromatism, allowing the size of the visual target to be adjusted to determine perception thresholds for accurate cone-specific testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the brightness difference between visual target and background is made large to improve detectability, then the subject can easily perceive the visual target, but the test becomes unreliable because the subject may be detecting brightness difference rather than color difference
Solution Approach 1:
The patent applies parameter changes by precisely controlling the brightness parameter to be within ±10% of the visual target, and by selecting specific color combinations (confusion colors in dichromatism) that minimize brightness differences while maximizing color discrimination difficulty. This resolves the contradiction by changing the brightness parameter to eliminate the harmful effect of brightness interference while maintaining test validity.
Solution Approach 2:
The patent applies local quality by creating specific local conditions in the visual stimulus design - using confusion colors that are specifically chosen to be difficult to distinguish for dichromats while maintaining similar brightness. This ensures that the test specifically targets color perception ability rather than general visual detectability.
2Measurement precision
If conventional color testing methods are used to detect color vision deficiency, then general color perception can be assessed, but cone-specific visual function (L-cone, M-cone, S-cone) cannot be accurately differentiated
Solution Approach 1:
The patent applies segmentation by dividing the color spectrum into specific wavelength ranges that selectively stimulate different cone types. By using confusion colors in dichromatism that target specific cone deficiencies (protanopia for L-cone, deuteranopia for M-cone, tritanopia for S-cone), the test segments the assessment into cone-specific measurements rather than general color perception.
Solution Approach 2:
The patent changes the color parameter to use specific confusion color combinations that are mathematically designed to be indistinguishable for specific cone deficiencies. This allows the test to specifically probe L-cone, M-cone, or S-cone function by selecting appropriate confusion color pairs, thereby achieving cone-specific measurement without requiring complex additional equipment.
3Measurement precision
If the visual target size is made large to improve visibility, then the subject can perceive the target more easily, but the test cannot determine the perception threshold
Solution Approach 1:
The patent applies dynamics by making the visual target size variable rather than fixed. The system dynamically adjusts the target size to find the perception threshold - presenting targets at different sizes and determining the minimum size at which the subject can reliably detect the target. This resolves the contradiction by using dynamic size adjustment to simultaneously assess both detectability and threshold.
Solution Approach 2:
The patent uses partial action by presenting visual targets at multiple different sizes rather than a single fixed size. By testing at various size levels (both larger and smaller than the threshold), the system can determine the precise perception threshold through the subject's responses, thereby obtaining accurate measurement while maintaining ease of detection at appropriate size levels.
Data Source
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AI summary
Provided is a visual target display device or a visual target presentation method which can test the cone-specific visual function more accurately in a device that displays a visual target, of a chromatic color, for testing the color-related visual function of a subject or a method of presenting the visual target. A visual target 8, of a chromatic color, for testing the color-related visual function of a subject and a background 9 around the visual target 8 are presented in such a way that the brightness of the background 9 is a numerical value between a numerical value 10% less than the brightness of the visual target 8 and a numerical value 10% greater than the brightness of the visual target 8 and a combination of the color of the visual target 8 and the color of the background 9 is a combination of colors which are in a relationship of confusion colors in dichromatism. The color of the background 9 is set to a chromatic color, for example. For example, the color of the visual target 8 and the color of the background 9 are set to chromatic colors located on opposite sides of a region of an achromatic color on the same confusion color locus passing through the region of the achromatic color in a chromaticity diagram. The color of the visual target 8 and the color of the background 9 are set to colors of the same chroma, for example.