Eye Tracker Visual Field Test Apparatus Fixation Drift
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Solution Overview
Problem
Existing visual field tests are subjective and prone to inaccuracies due to patient fixation and concentration issues, leading to unreliable measurements of peripheral vision.
Innovation Solution
A method using an eye tracker to monitor a patient's gaze and provide a marker on a display, guiding the patient to move their focus between fixation and visual field targets, with notifications and adjustable target visibility to maintain concentration and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional visual field tests are used where patients indicate when they see targets, then the test can be conducted with simple apparatus, but the measurement precision deteriorates due to subjective patient responses and fixation loss
Solution Approach 1:
The patent replaces the mechanical/manual system of patient self-reporting with an automated eye-tracking system using optical sensors and cameras to detect gaze position and fixation stability objectively, eliminating subjective response errors while maintaining test functionality
Solution Approach 2:
The patent introduces an intermediary eye-tracking system that mediates between the patient's visual perception and the measurement recording, using the marker-as-aid feature to bridge the gap between patient attention and accurate gaze detection
2Reliability
If patients are required to maintain fixation on a target, then the visual field measurement can be obtained, but the patient's concentration is lost leading to scanning behavior and inaccurate peripheral detection
Solution Approach 1:
The patent implements continuous feedback by monitoring eye position in real-time and providing visual feedback through the moving marker that indicates whether the patient is looking at the correct location, allowing immediate correction of fixation drift without breaking concentration
Solution Approach 2:
The moving marker serves as an intermediary visual aid that guides patient attention and provides continuous feedback about gaze position, making the fixation requirement easier to maintain while improving the detection of intentional vs. unintentional gaze shifts
3Stability of the object's composition
If the fixation target is made prominent to maintain patient focus, then fixation stability improves, but the visibility of peripheral visual field targets deteriorates
Solution Approach 1:
The patent uses periodic presentation of peripheral targets at different locations and durations, allowing the fixation target to remain prominent while still enabling detection of peripheral vision through timed, location-varied target stimulation
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
This approach ensures precise tracking of the patient's visual field, reducing inaccuracies and maintaining focus, resulting in a more reliable graphical representation of their visual field.
Implementation Method 1
tracking the patient's direction of gaze using an eye tracker to determine the patient's point of regard on the display
Data Source
AI summary
A method for testing a patient's (2) visual field using testing apparatus. A fixation target is provided on a display (3) at a known target position and the patient's (2) direction of gaze is tracked using an eye tracker to determine the patient's point of regard. A marker (5) is provided on the display (3) indicating the patient's (2) point of regard, where the marker (5) moves with movement of the patient's (2) point of regard. It is detected when the marker (5) is moved to the fixation target and a new target is then provided on the display at a further known target position. The new target is recorded as detected if the marker (5) is moved to the new target, with the new target then becoming the fixation target. The steps are repeated for further new targets for determining the patient's (2) visual field based on the positions of the new targets that have been detected.