Optometry Scale Using Processed Optotypes for Refraction Testing
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Solution Overview
Problem
Current eye refraction testing methods are either complex, time-consuming, and require a qualified professional, or they rely on expensive and unreliable equipment, failing to provide efficient and accurate estimation of spherical and astigmatic corrections without additional optical components.
Innovation Solution
A subjective-type optometry measuring scale with processed optotypes, which apply image processing to source optotypes for defined visual refraction corrections, allowing for simultaneous evaluation of eye refraction and astigmatism without additional lenses, enabling non-qualified individuals to perform tests quickly and accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional refraction measurement is performed using subjective testing with trial lenses, then precise optometric measurements can be obtained, but the process becomes complex and time-consuming requiring skilled personnel intervention
Solution Approach 1:
The testing process is segmented into two independent parts: (1) astigmatism axis detection using the Parent Dial chart, and (2) spherical and cylindrical degree measurement using the processed optotype scale. This segmentation allows each sub-test to be simple and independent, eliminating the need for complex trial lens procedures while maintaining measurement precision.
Solution Approach 2:
The astigmatism axis is detected first using the Parent Dial chart before proceeding to the main refraction measurement. This preliminary action simplifies the subsequent testing by pre-determining the axis orientation, allowing the processed optotype scale to focus only on measuring spherical and cylindrical degrees without needing to determine axis orientation during the same test.
2Measurement precision
If a full set of trial lenses is used for refraction measurement, then accurate correction values can be determined, but expensive equipment and skilled personnel are required
Solution Approach 1:
Instead of using physical trial lenses, the invention creates optical copies of optotypes with pre-calculated blur characteristics. The processed optotypes are generated by convolving source optotypes with point spread functions corresponding to different spherical and cylindrical correction values, effectively copying the optical effect of trial lenses in a static, inexpensive visual scale format.
Solution Approach 2:
The invention changes the parameter of the optotypes themselves rather than using physical lenses. By modifying the point spread function parameters of the displayed optotypes to match different correction values, the system encodes correction information directly in the visual patterns, eliminating the need for expensive trial lens sets while maintaining measurement accuracy.
3Difficulty of detecting and measuring
If conventional astigmatic test charts are used, then axis orientation can be detected, but the method is not reliable for determining cylindrical degree of correction
Solution Approach 1:
Different regions of the visual scale have different local qualities optimized for specific measurements. The Parent Dial chart uses radial line segments with uniform properties for axis detection, while the processed optotype scale uses characters or symbols with varying blur characteristics corresponding to different spherical and cylindrical correction values. This local quality differentiation enables reliable measurement of both axis orientation and cylindrical degree using simple visual inspection.
Data Source
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AI summary
The invention concerns an optometry measuring scale and method for determining a visual refraction value of an individual. According to the invention, the optometry measuring scale comprises a plurality of processed optotypes (2H) associated with a plurality of visual refraction corrections, wherein each processed optotype (2H) results from applying to a source optotype (2E) a determined image processing (2F) associated with a defined visual refraction correction, and an identification system (2G) for determining each defined visual refraction correction associated with each processed optotype (2H).