Abstract
Purpose :
Amsler grid is often digitally reproduced on mobile devices and web sites, interfaces that allow a greater range of supportive functionalities (reminders, history tracking, resources), but for which diagnostic validity has not been demonstrated.
Methods :
Cross-over study of 145 eyes in 100 patients with pre-existing diagnoses of macular disease. Paper and digital Amsler grids were viewed with each affected eye individually, to compare sensitivity of these media in eliciting visually-significant macular pathology. Each eye served as its own control. Eyes without macular disease or with BCVA worse than 20/150 were excluded. Macular pathologies included age-related macular degeneration with and without neovascularization (n=73), diabetic macular edema (n=27), and epiretinal membrane (n=32). The primary outcome was number of visual field defects (VFDs), defined as any scotoma or metamorphopsia reported by the participant while viewing the grid. Wilcoxon signed rank test and sign test were used for statistical analyses. Subjects were also asked to compare the subjective experience of viewing the grid on paper and digitally.
Results :
Among 100 participants, 65% were female (mean age of 64.4±14.2). Collectively, 145 eyes with macular disease were assessed. There was no significant difference between media in the number of eyes reporting VFDs (p = 0.18, two tailed). A discrepancy between media in the number of VFDs detected per eye, however, was noted in 21 eyes, with an overall mean difference of 0.12 VFDs more per eye viewing the digital grid (SD=0.67). This difference, as evaluated by the Wilcoxon signed rank test, showed greater sensitivity of the digital version and was statistically significant (p=0.013) Qualitatively, participants reported greater clarity of the digital Amsler grid image, ascribed to higher contrast and backlight illumination.
Conclusions :
The digital Amsler grid was found to be more sensitive than paper in detecting VFDs in eyes affected by visually-significant macular disease. These findings support the use of Amsler grid via digital interfaces as a validated screening tool. The study is a first step in bringing an evidence-based mobile application for self-screening to patients with macular disease.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.