Dynamic Fixation Stimulus for Visual Field Testing
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Solution Overview
Problem
Current visual field testing and therapy methods face challenges in maintaining continuous fixation due to retinal adaptation, limiting the accuracy and effectiveness of diagnostic and therapeutic programs, as they rely on static stimuli that cause desensitization and are not effective in detecting motion sensitivity across the entire visual field.
Innovation Solution
A dynamic fixation stimulus is presented on a computer-driven display, altered to prevent retinal adaptation, allowing prolonged fixation by varying characteristics such as translation, rotation, or luminosity, and used in conjunction with a test cue to maintain subject engagement and record responses, targeting specific retinal regions and activating both motion-detecting and detail-processing pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a static fixation stimulus is used, then the testing procedure is simple, but the subject's retinal cells adapt to the stimulus and fixation cannot be maintained continuously
Solution Approach 1:
The fixation stimulus is transformed from a static image to a dynamically changing stimulus that alters its characteristics (such as position, size, or luminosity) at regular intervals. This dynamic modification prevents retinal adaptation while maintaining the subject's fixation attention, allowing continuous testing without the limitations of static stimuli.
Solution Approach 2:
The stimulus undergoes periodic changes in its properties at predetermined intervals during the fixation period. These regular alterations reset the retinal cells' adaptation process, enabling the subject to maintain fixation continuously throughout the extended testing duration without experiencing stimulus-induced adaptation.
2Measurement precision
If static perimetry is used, then fine light sensitivity can be established, but motion sensitivity at all points within the borders cannot be identified efficiently
Solution Approach 1:
The fixation stimulus dynamically changes its characteristics during presentation, introducing motion elements that stimulate both P-cells (detail processing) and M-cells (motion detection). This allows simultaneous assessment of fine light sensitivity and motion sensitivity without requiring separate testing procedures.
Solution Approach 2:
The dynamic fixation stimulus serves multiple functions simultaneously: it maintains fixation attention, stimulates detail-processing pathways, and activates motion-detecting pathways. This multi-functionality enables comprehensive visual field assessment including both static and motion sensitivity within a single testing paradigm.
3Productivity
If kinetic perimetry is used, then motion vision function borders can be identified, but fine light sensitivity within the central visual field cannot be established
Solution Approach 1:
The dynamic fixation stimulus incorporates controlled motion and change elements that stimulate motion-detecting M-cells in the peripheral visual field, enabling identification of motion vision borders. Simultaneously, the central fixation requirement and detailed stimulus changes maintain engagement of P-cells for fine light sensitivity measurement in the central field.
Solution Approach 2:
The testing method universally addresses both motion vision assessment and fine light sensitivity measurement through a single dynamic stimulus paradigm, eliminating the need to choose between kinetic perimetry's motion border identification and static perimetry's central field sensitivity measurement.
4Device complexity
If the fixation stimulus remains unchanged, then the testing setup is simple, but retinal adaptation occurs and testing accuracy decreases
Solution Approach 1:
The fixation stimulus is programmed to automatically alter its characteristics (position, size, luminosity, or other properties) at predetermined intervals without requiring complex manual intervention. This automated dynamic modification maintains testing accuracy by preventing retinal adaptation while keeping the overall testing setup relatively simple through computer control.
Solution Approach 2:
The stimulus parameters (such as position coordinates, size dimensions, or luminosity levels) are systematically changed during the fixation period according to predetermined patterns. These parameter modifications prevent retinal adaptation and maintain measurement precision without requiring fundamentally complex testing equipment.
Data Source
AI summary
Alteration of a fixation or peripheral stimulus displayed on a computer-driven display allows a human subject to maintain extended visual fixation upon the resulting dynamic stimulus. The fixation is presented upon the display and the stimulus is altered to allow resensitization of the subject's retina, thereby allowing prolonged visual fixation upon the resulting dynamic target. A dynamic stimulus may utilize a frequency doubling illusion.