Test-retest Reliability of Psychophysical Tasks Using Structured Light-Induced Entoptic Phenomena
Abstract
Structured light (SL)-induced polarization perception presents a promising method for the early detection of macular diseases such as age-related macular degeneration. We investigated the test-retest reliability of a psychophysical task using SL-based stimuli to induce entoptic patterns in individuals with healthy vision. Twenty-eight participants underwent thorough eye examinations to confirm they had healthy eyes and good vision (logMAR BCVA ~0.00). Of these, 25 participants (n=50 eyes) aged 21 to 75 completed two identical tasks separated by 1 to 14 days. Using SL-based stimuli that produced a rotating entoptic pattern containing 22 azimuthal brushes, we measured the retinal eccentricity threshold at which participants could reliably identify the direction of rotation by varying the size of a central obstruction. This threshold reflects the visual angle of the pattern for each participant. We calculated the reliability coefficient (intraclass correlation coefficient, ICC) using a two-way mixed-effects model and conducted a Bland-Altman analysis to assess test-retest reliability. The ICC was 0.83 [95% CI: 0.62 - 0.93] for right eyes (RE) and 0.93 [95% CI: 0.84 - 0.97] for left eyes (LE), indicating good reliability. The Bland-Altman analysis showed a mean difference of -0.32{\deg} (SD: 1.51) and -0.12{\deg} (SD: 1.03) for RE and LE respectively between the first and second sessions, with limits of agreement ranging from -3.28{\deg} to 2.64{\deg} and -2.14{\deg} to 1.89{\deg} for RE and LE respectively, confirming strong agreement and no significant bias. These results demonstrate that SL-based psychophysical tasks are a reliable method for assessing polarization perception, potentially improving screening for diseases affecting macular health.
Cite
@article{arxiv.2602.08836,
title = {Test-retest Reliability of Psychophysical Tasks Using Structured Light-Induced Entoptic Phenomena},
author = {Taranjit Singh and Mukhit Kulmaganbetov and Zhangting Wang and Dmitry Pushin and Benjamin Thompson and Andrew Silva and Melanie Mungalsingh and Iman Salehi and Davis Garrad and David Cory and Dusan Sarenac},
journal= {arXiv preprint arXiv:2602.08836},
year = {2026}
}