Test-retest Reliability of Psychophysical Tasks Using Structured Light-Induced Entoptic Phenomena

Taranjit Singh; Mukhit Kulmaganbetov; Zhangting Wang; Dmitry Pushin; Benjamin Thompson; Andrew Silva; Melanie Mungalsingh; Iman Salehi; Davis Garrad; David Cory; Dusan Sarenac

arXiv · 2602.08836

Test-retest Reliability of Psychophysical Tasks Using Structured Light-Induced Entoptic Phenomena

Taranjit Singh·Mukhit Kulmaganbetov·Zhangting Wang·Dmitry Pushin·Benjamin Thompson·Andrew Silva·Melanie Mungalsingh·Iman Salehi·Davis Garrad·David Cory·Dusan Sarenac

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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 $R_T$ 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.

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Taranjit Singh, Mukhit Kulmaganbetov, Zhangting Wang, Dmitry Pushin, Benjamin Thompson, Andrew Silva, Melanie Mungalsingh, Iman Salehi, Davis Garrad, David Cory, Dusan Sarenac. 2026-02-09. Test-retest Reliability of Psychophysical Tasks Using Structured Light-Induced Entoptic Phenomena. https://arxiv.org/abs/2602.08836

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