Contrast Sensitivity Threshold Detection via Optokinetic Nystagmus Tracking
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Solution Overview
Problem
Current contrast sensitivity tests require an experienced examiner and active user attention, limiting their applicability and accuracy, especially for individuals with low cooperation or vision impairments.
Innovation Solution
A method and device that automatically determine contrast sensitivity thresholds by tracking eye movements stimulated with an optokinetic nystagmus-inducing stimulus, using velocity and fractional thresholds to classify eye movements and calculate contrast sensitivity without user cooperation, implemented in a computer program and device such as a virtual reality headset with an eye tracker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional contrast sensitivity tests (e.g., Hiding Heidi, LEA low-contrast symbol test) are used, then contrast sensitivity can be examined, but the tests require an experienced examiner and active user cooperation, limiting applicability
Solution Approach 1:
The system uses automated eye tracking technology to capture and analyze eye movements without requiring user cooperation or examiner intervention. The optokinetic nystagmus response is measured automatically through the eye tracker, which records eye position data and processes it to determine contrast sensitivity thresholds, enabling the system to serve itself without human input during the actual measurement
Solution Approach 2:
The patent replaces the manual mechanical examination process with an automated optical and computational system. Instead of requiring an examiner to manually evaluate eye movements and interpret results, the system uses an eye tracker with automated data processing algorithms to measure optokinetic nystagmus and calculate contrast sensitivity thresholds, substituting mechanical human judgment with automated technological measurement
2Measurement precision
If traditional contrast sensitivity tests are used, then contrast sensitivity can be determined, but the tests are time-consuming and require trained personnel
Solution Approach 1:
The system performs preliminary calibration of the eye tracker and pre-configures the optokinetic nystagmus stimulus parameters before the actual measurement. The automated processing algorithms are pre-loaded and ready to immediately analyze eye movement data, eliminating the time required for manual setup and analysis that plagues traditional methods
Solution Approach 2:
The system creates a controlled, standardized testing environment with fixed stimulus parameters and automated data collection protocols. This inert, standardized approach eliminates variability introduced by human examiners and reduces the time needed for subjective interpretation, allowing rapid automated determination of contrast sensitivity thresholds
3Extent of automation
If automated eye tracking is used to measure optokinetic nystagmus, then user cooperation is minimized, but the device complexity increases
Solution Approach 1:
The eye tracking system is designed to perform multiple functions: it tracks eye position, measures optokinetic nystagmus response, and processes data to determine contrast sensitivity thresholds. This multi-functional approach consolidates what could be separate complex systems into a single integrated device, reducing overall system complexity while maintaining high automation
Solution Approach 2:
The patent uses the natural optokinetic nystagmus response as an intermediary between the visual stimulus and the measurement outcome. The eye tracker captures this intermediate eye movement signal, which automatically encodes contrast sensitivity information, eliminating the need for complex direct measurement techniques and simplifying the overall measurement process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables quick, objective, and accurate contrast sensitivity testing with minimal user cooperation, suitable for untrained personnel and potentially at home, allowing for regular monitoring and early detection of visual function degradation.
Implementation Method 1
providing a dataset of track data, wherein the track data comprise data of eye movements, wherein the eye movements are stimulated by a stimulus which is designated for eliciting an optokinetic nystagmus in the eyes of the user
Data Source
AI summary
A method and a device allow to determine the contrast sensitivity threshold of the eyes of a user in an automatic manner without requiring an experienced examiner or active attention of the user. The method includes: a) providing a dataset of track data including data of eye movements, wherein the eye movements are stimulated to elicit an optokinetic nystagmus in the eyes of the user and wherein the track data are related to a particular contrast and spatial frequency of the stimulus; b) estimating at least one velocity component of the eye movement; c) comparing the velocity component with a velocity threshold; d) comparing a fraction of the track data which exceed the velocity threshold with a fractional threshold for the dataset, which is classified as eliciting the optokinetic nystagmus at the particular contrast of the stimulus; and e) determining the contrast sensitivity threshold of the eyes of the user.