Headset Stereo Alignment Measurement for Objective Phoria Correction
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Solution Overview
Problem
Existing methods for determining binocular alignment suffer from high variability and subjectivity, leading to inconsistent prismatic corrections for accommodative misalignments, and lack of consideration for both central and peripheral vision, as well as dynamic eye responses.
Innovation Solution
A method and system using a headset with a stereo display and eye tracker to objectively measure disassociated and associated phoria by presenting fusible and non-fusible images, incorporating both central and peripheral tests, and dynamic image presentation to determine optimal prismatic corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods for determining binocular alignment are used, then the measurement process is simple, but the measurement precision and reliability are poor due to high variability and subjectivity
Solution Approach 1:
The measurement process is segmented into multiple independent components: presenting fusible images to measure associated phoria, presenting non-fusible images to measure disassociated phoria, and using eye trackers to objectively measure eye positions. Each component contributes to the overall measurement precision without requiring the entire complex system to be activated simultaneously, thus improving reliability while managing complexity.
Solution Approach 2:
A computer-controlled headset system serves as an intermediary between the patient and the measurement process. The headset presents standardized visual stimuli (fusible and non-fusible images) and captures objective eye position data through integrated eye trackers, eliminating subjectivity from the measurement while managing complexity through automated control.
2Adaptability or versatility
If only central vision tests are used, then the test procedure is simple, but the adaptability is poor because peripheral accommodative misalignments are not compensated
Solution Approach 1:
The measurement system applies different test conditions to different regions of vision: central vision is tested using fusible images presented at the center of the visual field, while peripheral vision is tested using non-fusible images presented in the peripheral visual field. Each region receives the appropriate local treatment, improving adaptability while managing complexity through region-specific protocols.
Solution Approach 2:
The measurement system is designed to perform multiple functions within a single unified protocol: it measures both associated phoria (central vision) and disassociated phoria (peripheral vision) using the same headset and eye tracking technology, making the system versatile without proportionally increasing complexity.
3Reliability
If static image presentation is used, then the system is simple, but the reliability is poor because dynamic eye responses are not captured
Solution Approach 1:
The measurement system transitions from static to dynamic image presentation, where visual stimuli are continuously updated and adjusted based on real-time eye position feedback from the eye trackers. This dynamic adaptation captures the natural movement and response of the eyes, improving measurement reliability while managing complexity through automated feedback control.
Solution Approach 2:
The system implements closed-loop feedback by continuously monitoring eye positions through eye trackers and using this information to adjust the presentation of visual stimuli in real-time. This feedback mechanism ensures that the measurement captures dynamic eye responses, improving reliability while the automated control manages the complexity of the feedback loop.
Data Source
AI summary
A method to determine a binocular alignment includes measuring a disassociated phoria of a patient at a first simulated distance by presenting fusible images including targets with a first parallax corresponding to the first simulated distance, using a headset stereo display at a screen distance; presenting non-fusible images by presenting the target for a first eye with the first parallax and presenting a disassociated targetless image for a second eye, and measuring the disassociated phoria in response to the presenting of non-fusible images, using an eye tracker of the headset; and determining a vergence of the patient at the first simulated distance by presenting fusible images for the first and second eyes with the first parallax, corrected with the measured disassociated phoria; measuring an associated phoria in response to the presenting of fusible images; and determining the vergence as a combination of the disassociated phoria and the associated phoria.