Natural Image Refraction Testing System
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Solution Overview
Problem
Current methods for determining subjective refractive properties of the eye using standardized optotypes do not accurately reflect everyday visual conditions, leading to suboptimal results due to unnatural testing situations and pressure on test subjects, which can result in deviations between determined and actual refractive errors.
Innovation Solution
The use of natural images with spatial frequency-dependent contrast, allowing for refraction determination under conditions that mimic everyday life, where the contrast decreases with increasing spatial frequency, and incorporating features that resemble typical environments to reduce test subject pressure and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standardized optotypes are used for refraction determination, then measurement precision is improved, but the test subject experiences unnatural visual conditions and stress, reducing reliability of the results
Solution Approach 1:
The patent changes the fundamental parameter of the test stimulus from standardized geometric optotypes to natural images with spatial frequency-dependent contrast. This transformation allows the test to maintain measurement precision while improving reliability by creating a more natural and relaxed testing condition that better reflects everyday visual experiences.
Solution Approach 2:
The patent applies local quality by incorporating specific spatial frequency-dependent contrast characteristics into the natural images used for testing. Different spatial frequency regions of the natural images are optimized to provide appropriate contrast levels, creating localized visual challenges that maintain measurement precision while overall natural appearance improves reliability.
2Measurement precision
If standardized optotypes with high contrast are used, then measurement precision is improved, but the testing situation becomes unnatural and stressful for the subject
Solution Approach 1:
The patent transforms the test stimulus from high-contrast geometric optotypes to natural images with spatial frequency-dependent contrast. This parameter change maintains the ability to precisely measure visual acuity while making the testing procedure more natural and less stressful for the subject.
Solution Approach 2:
Instead of using artificial high-contrast geometric shapes to test vision, the patent inverts the approach by using natural images that would normally be encountered in everyday life. The contrast is distributed according to spatial frequency rather than being uniformly high, creating a more natural and relaxed testing experience.
3Reliability
If natural images with spatial frequency-dependent contrast are used, then reliability of refractive error determination is improved, but device complexity increases
Solution Approach 1:
The patent uses copies or representations of natural images that have been processed to incorporate spatial frequency-dependent contrast characteristics. Rather than requiring complex real-time processing of arbitrary natural scenes, the system uses pre-processed image copies with optimized contrast properties, reducing device complexity while maintaining reliability.
Data Source
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AI summary
The present invention relates to a system (10) for determining the subjective refraction properties of an eye (20) of a test subject based on the use of a natural image (30), said system having the following: a memory (11) in which at least one natural image (30) is stored; a display device (12) for displaying the at least one natural image (30) from the memory (11); a lens arrangement (13) for adjusting various light-refracting elements (14, 15) in an optical path between the eye (20) of the test subject and the display device (12), wherein the lens arrangement (13) is arranged at a predefined distance (d) from the display device (12). The present invention further relates to a corresponding method and the use of a natural image (30) for refraction determination.