Accepted for/Published in: JMIR Human Factors
Date Submitted: Jul 1, 2025
Date Accepted: Feb 21, 2026
Usability Evaluation of a Macular Quantitative Square Grid Self-examination Application in patients with macular disease: Mixed Methods Study
ABSTRACT
Background:
Digital self-monitoring applications could provide individuals with macular disease with a convenient, quantitative method for tracking metamorphopsia at home; yet the usability of such tools remains to be fully established.
Objective:
This study evaluated the usability of GridMacuScan, a semi-quantitative, touch-based self-monitoring application for macular function.
Methods:
This study employed a convergent mixed-methods design. The application quantifies (i) distortion severity, (ii) distortion area, and (iii) temporal trends through a three-step touch interface. A total of twenty-four adults with neovascular age-related macular degeneration or diabetic macular edema, accompanied by self-reported metamorphopsia, participated in a single supervised test session. A 10-item System Usability Scale was utilized to assess usability, and semi-structured interviews were conducted to gather further insights. Quantitative data were summarized descriptively; qualitative feedback underwent inductive thematic analysis.
Results:
All eyes that showed distortion on the Amsler grid also produced positive distortion maps on GridMacuScan, yielding 100 % diagnostic concordance. The mean SUS score was 82.1 ± 8.7, indicating “good–excellent” usability. The inductive thematic analysis yielded four overarching themes: (1) high usability and positive overall experience, (2) perceived functional advantages, (3) shortcomings and optimization suggestions, and (4) strong willingness for continued use.
Conclusions:
GridMacuScan demonstrated diagnostic sensitivity comparable to that of the traditional Amsler grid and received high user ratings for usability. Furthermore, it provided quantitative distortion metrics that could facilitate longitudinal disease surveillance. Future research must be conducted to validate performance in unsupervised home environments and investigate whether sustained use improves time-to-disease-progression detection and treatment outcomes. Clinical Trial: none
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