{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T21:02:37Z","timestamp":1790197357236,"version":"4.1.0"},"reference-count":0,"publisher":"SPIE-Intl Soc Optical Eng","issue":"06","license":[{"start":{"date-parts":[[2026,2,12]],"date-time":"2026-02-12T00:00:00Z","timestamp":1770854400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Israeli Ministry of Science and Technology, Science Forefront Program","award":["0006061"],"award-info":[{"award-number":["0006061"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Biomed. Opt."],"published-print":{"date-parts":[[2026,2,12]]},"abstract":"<jats:p>SignificanceAccurate monitoring of pupil size and gaze direction is critical in clinical and research contexts; however, current pupillometry methods require open eyes, limiting their use in patients under anesthesia, sedation, or sleep. Short-wave infrared (SWIR) imaging enables noninvasive closed-eye pupillometry, but challenges remain due to eyelid glare, gaze variability, and low signal-to-noise ratio (SNR).AimWe aimed to enhance closed-eye pupillometry by integrating polarization filters into the SWIR imaging system and developing improved algorithms for pupil localization and gaze direction estimation under natural closed-eye conditions.ApproachExperiments were conducted on healthy volunteers using SWIR imaging with different polarizer configurations (parallel, partially crossed, crossed, and no polarizers). Pupillary light reflexes (PLR) were recorded under open- and closed-eye conditions with both forward fixation and varying gaze directions. Image analysis incorporated brightness difference imaging and statistical modeling to evaluate maximal brightness change and SNR.ResultsIn open-eye settings, parallel polarizers produced the strongest PLR signal, but in closed-eye conditions, crossed polarizers significantly improved image quality by suppressing eyelid glare. The crossed configuration yielded the highest PLR brightness change and SNR compared with parallel or no polarizers, enabling reliable pupil localization across multiple gaze directions. Improved algorithms allowed robust PLR detection even under natural eyelid closure and variable gaze positions.ConclusionsIntegrating crossed polarizers into SWIR-based pupillometry substantially enhances signal fidelity and pupil localization through closed eyelids. This approach overcomes major limitations of previous methods and enables accurate, touchless pupillometry in clinically relevant conditions. These advances pave the way for applications in anesthesiology, sleep medicine, and neurocritical care.<\/jats:p>","DOI":"10.1117\/1.jbo.31.6.064303","type":"journal-article","created":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T01:20:55Z","timestamp":1770945655000},"page":"1-14","source":"Crossref","is-referenced-by-count":1,"title":["Polarizer-assisted pupillometry through closed eyelids, overcoming pupil position dependence"],"prefix":"10.1117","volume":"31","author":[{"given":"Michal","family":"Tepper","sequence":"first","affiliation":[{"name":"Tel Aviv Univ."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Omer","family":"Ben Barak-Dror","sequence":"additional","affiliation":[{"name":"Tel Aviv Univ."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Haggiag","sequence":"additional","affiliation":[{"name":"Tel Aviv Univ."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Israel","family":"Gannot","sequence":"additional","affiliation":[{"name":"Tel Aviv Univ."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5433-6349","authenticated-orcid":false,"given":"Yuval","family":"Nir","sequence":"additional","affiliation":[{"name":"Tel Aviv Univ."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"189","container-title":["Journal of Biomedical Optics"],"original-title":[],"link":[{"URL":"https:\/\/www.spiedigitallibrary.org\/journals\/journal-of-biomedical-optics\/volume-31\/issue-06\/064303\/Polarizer-assisted-pupillometry-through-closed-eyelids-overcoming-pupil-position-dependence\/10.1117\/1.JBO.31.6.064303.full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T20:20:41Z","timestamp":1790194841000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.spiedigitallibrary.org\/journals\/journal-of-biomedical-optics\/volume-31\/issue-06\/064303\/Polarizer-assisted-pupillometry-through-closed-eyelids-overcoming-pupil-position-dependence\/10.1117\/1.JBO.31.6.064303.full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,12]]},"references-count":0,"journal-issue":{"issue":"06","published-online":{"date-parts":[[2026,6,1]]}},"URL":"https:\/\/doi.org\/10.1117\/1.jbo.31.6.064303","relation":{},"ISSN":["1083-3668","1560-2281"],"issn-type":[{"value":"1083-3668","type":"print"},{"value":"1560-2281","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,12]]}}}