Dynamic Optotype Scaling for Mobile Visual Acuity Testing
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Solution Overview
Problem
Existing methods for determining visual acuity at a distance are cumbersome, require expensive and bulky refraction units, and are not easily adaptable to variable test distances, making them impractical for mobile use or home visits.
Innovation Solution
A method using a mobile computer to detect individual test distances and scale digital optotype images accordingly, allowing for dynamic adjustment of optotype size based on standardized rules, eliminating the need for physical test charts or refraction units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If permanently installed refraction units are used, then measurement precision is improved, but device complexity and acquisition costs increase significantly
Solution Approach 1:
The patent uses a camera to capture images of the test subject's eyes and processes these images computationally to determine visual acuity. This replaces the complex optical systems of traditional refraction units with a simple camera and software algorithm, achieving comparable measurement precision through digital image processing rather than complex optical hardware
Solution Approach 2:
The patent replaces the mechanical and optical systems of traditional refraction units (including projectors, lenses, and manual calibration mechanisms) with a digital system using a camera, image processing algorithms, and computer-controlled display. This substitution eliminates the need for manual calibration and complex mechanical adjustment mechanisms while maintaining measurement accuracy
2Ease of operation
If traditional test charts are used, then ease of operation is improved, but adaptability to variable testing distances deteriorates
Solution Approach 1:
The patent uses a display device (such as a screen or projector) that can dynamically adjust the size and position of optotypes based on the detected testing distance. The system automatically scales the visual acuity symbols according to the measured distance between the camera and the test subject, eliminating the need for multiple physical test charts with different fixed sizes
Solution Approach 2:
The patent changes the parameter of optotype size dynamically based on the detected testing distance. The system measures the distance between the camera and the test subject's eyes, then automatically adjusts the display size of the visual acuity symbols to maintain appropriate viewing conditions, allowing a single test chart to be used across multiple testing distances
3Ease of operation
If test charts are transported for mobile use, then ease of operation is improved, but reliability and durability deteriorate due to wear and tear
Solution Approach 1:
The patent replaces physical test charts with digital images displayed on a screen or projected onto a surface. This digital copy eliminates the physical wear and tear that occurs with transporting and handling traditional test charts, while maintaining the visual information needed for the visual acuity test
Solution Approach 2:
The patent replaces the mechanical system of physical test charts with a digital display system. The optotypes are rendered as digital images that can be displayed indefinitely without degradation, eliminating issues related to paper deterioration, folding, staining, and other forms of physical wear that affect traditional test charts
4Adaptability or versatility
If multiple test charts are carried for different distances, then adaptability is improved, but device complexity and portability worsen
Solution Approach 1:
The patent creates a universal test system where a single digital display can present optotypes at any size and distance appropriate for the testing situation. The system automatically adapts to different testing distances by detecting the camera-to-subject distance and adjusting the displayed symbol size accordingly, eliminating the need to carry multiple specialized test charts for different purposes
Solution Approach 2:
The patent implements a dynamic system that automatically adjusts optotype size based on the detected testing distance. Rather than requiring static test charts designed for specific distances, the system continuously adapts the display parameters to match the actual testing conditions, providing versatility without increasing physical complexity
Data Source
AI summary
In a method for providing optotypes for determining distance visual acuity, a test subject position is provided for a test subject and a display surface at a display position. An individual test distance between the test subject position and the display position is, for example, detected automatically. An individual target variable is determined for optotypes which are matched to the detected individual test distance according to a predetermined rule. Digital optotype image data are provided which contain optotypes scaled to the individual target variable. The digital optotype image data are displayed on the display surface.