Continuous Sinusoidal Grating Contrast Vision Test
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Solution Overview
Problem
Existing contrast vision tests are inadequate for normally ametropic subjects as they have too crude gradations and do not cover the entire contrast and visual acuity range, lacking a meaningful metric for automatic digital processing.
Innovation Solution
A method using a continuous sinusoidal grating where spatial frequency and contrast vary continuously, allowing subjects to perceive and mark their individual contrast sensitivity function, which can be determined through a computer program and displayed on a device with sufficient resolution and contrast ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete visual acuity and contrast values are measured using traditional methods, then the test can be performed with simple measurement objects, but the gradations are too crude for normally ametropic persons and do not cover the entire contrast and visual acuity range
Solution Approach 1:
The patent transforms the static discrete measurement approach into a dynamic continuous measurement approach. The sinusoidal grating pattern allows spatial frequency and contrast to vary continuously, enabling precise measurement of contrast sensitivity across the entire visual acuity range rather than at discrete points only.
Solution Approach 2:
The patent changes the measurement parameters from discrete fixed values to continuous variable values. By using a sinusoidal grating where spatial frequency and contrast can take any value within a range, the system achieves fine continuous resolution suitable for normally ametropic persons.
2Extent of automation
If discrete points in visual acuity/contrast scheme are registered, then the evaluation can be performed visually, but no continuous data is digitally registered that would enable automatic further processing
Solution Approach 1:
The patent replaces the manual visual evaluation method with an automated digital processing system. The continuous data from the sinusoidal grating measurement is digitally registered and processed by a computer program, eliminating the need for manual visual comparison and enabling automatic calculation of the contrast sensitivity function.
3Adaptability or versatility
If traditional contrast vision tests are used, then they work for partially sighted persons, but they are inadequate for normally ametropic subjects who require finer resolution
Solution Approach 1:
The patent creates a universal test method that works for both partially sighted persons and normally ametropic subjects. The continuous sinusoidal grating approach provides fine resolution for normally ametropic persons while still being applicable to partially sighted persons, making the test universally suitable for different visual conditions.
Data Source
AI summary
The invention relates to a method for performing a contrast vision test on a subject in order to determine a contrast sensitivity function. According to said method, an image of a continuous sinusoidal grid is presented to the subject for viewing, the spatial frequency continuously changes in the direction of a first axis, and the contrast continuously changes in the direction of a second axis that extends perpendicular to the first axis. The subject's contrast sensitivity function is defined by means of a curve that encloses an area of the sinusoidal grid in which the subject perceives the sinusoidal grid pattern during viewing.