Metamorphopsia Testing via Binary Grid Segmentation
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Solution Overview
Problem
Current visual acuity testing methods, such as the Amsler grid test, are time-consuming and difficult for patients to perform accurately, especially those with age-related macular degeneration, due to challenges in maintaining fixation and marking distortions on a touch screen.
Innovation Solution
A method using a mobile device to display a fixation point and series of straight lines, where users provide binary input on distortion presence, allowing the system to progressively divide the test area into segments, reducing the number of steps and eliminating non-distorted sections, enabling precise quantification of visual distortions without requiring patients to mark distortions directly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If patients mark distorted areas on the grid using a touch screen, then distortion locations can be identified, but the testing becomes time-consuming and cognitively difficult due to the need to maintain fixation while drawing
Solution Approach 1:
The test area is divided into multiple discrete segments or zones. Instead of requiring continuous drawing, patients simply indicate which segments appear distorted. This segmentation reduces the cognitive load and time required while maintaining accurate localization of distortion areas.
Solution Approach 2:
The system introduces an intermediary processing layer where the device automatically analyzes and quantifies distortion based on patient responses to segmented areas. This intermediary computation reduces the burden on the patient while preserving measurement precision.
2Measurement precision
If patients draw on the touch screen to mark distortions, then distortion areas can be quantified, but fixation is lost as the eye moves from the fixation point to the finger
Solution Approach 1:
By dividing the grid into discrete segments, the patient only needs to indicate which segments are distorted rather than continuously drawing. This eliminates sustained eye-finger coordination and maintains fixation reliability.
Solution Approach 2:
Instead of moving the finger to mark the distortion location (which breaks fixation), the system inverts the approach by having the patient indicate distortion presence in pre-defined segments while maintaining fixation on the central point.
3Measurement precision
If the Amsler grid test is made comprehensive to detect all distortions, then measurement precision improves, but the number of steps and cognitive effort increase
Solution Approach 1:
The comprehensive grid is segmented into multiple zones that can be independently evaluated. This allows systematic coverage of the entire visual field while reducing the cognitive burden through structured, stepwise assessment of each segment.
Solution Approach 2:
The system uses a multi-phase approach where initial coarse segmentation identifies general distortion areas, followed by optional finer segmentation only in regions of interest. This partial action approach maintains comprehensive detection capability while reducing overall test complexity for patients with mild symptoms.
Data Source
AI summary
A visual distortion test is disclosed using a sequence of binary interactions with a mobile device, in which segments of the grid having no distortions are eliminated, and the segments with distortions are divided into smaller segments for further analysis. The test can quantify the visual distortion using a decreased number of steps, compared to sequential analysis of all the segments of the grid. The binary interaction or input to the mobile device is also easier for patients than graphic interactions with a conventional Amsler Grid. Early detection of changes in the visual distortion can enable the healthcare provider to individualize treatment, helping to prevent vision loss while minimizing visits to the office, discomfort, and expense.