{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,14]],"date-time":"2026-02-14T02:03:34Z","timestamp":1771034614196,"version":"3.50.1"},"reference-count":27,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2024,3,9]],"date-time":"2024-03-09T00:00:00Z","timestamp":1709942400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"National Funds through FCT\u2014Portuguese Foundation for Science and Technology","doi-asserted-by":"publisher","award":["PD\/BDE\/135002\/2017"],"award-info":[{"award-number":["PD\/BDE\/135002\/2017"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Chromatic Pupillometry, used to assess Pupil Light Reflex (PLR) to a coloured light stimulus, has regained interest since the discovery of melanopsin in the intrinsically photosensitive Retinal Ganglion Cells (ipRGCs). This technique has shown the potential to be used as a screening tool for neuro-ophthalmological diseases; however, most of the pupillometers available are expensive and not portable, making it harder for them to be used as a widespread screening tool. In this study, we developed a smartphone-based system for chromatic pupillometry that allows targeted stimulation of the ipRGCs. Using a smartphone, this system is portable and accessible and takes advantage of the location of the ipRGCs in the perifovea. The system incorporates a 3D-printed support for the smartphone and an illumination system. Preliminary tests were carried out on a single individual and then validated on eleven healthy individuals with two different LED intensities. The average Post-Illumination Pupil Light Response 6 s after the stimuli offsets (PIPR-6s) showed a difference between the blue and the red stimuli of 9.5% for both intensities, which aligns with the studies using full-field stimulators. The results validated this system for a targeted stimulation of the ipRGCs for chromatic pupillometry, with the potential to be a portable and accessible screening tool for neuro-ophthalmological diseases.<\/jats:p>","DOI":"10.3390\/bioengineering11030267","type":"journal-article","created":{"date-parts":[[2024,3,11]],"date-time":"2024-03-11T06:05:30Z","timestamp":1710137130000},"page":"267","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Development of a Smartphone-Based System for Intrinsically Photosensitive Retinal Ganglion Cells Targeted Chromatic Pupillometry"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2980-4742","authenticated-orcid":false,"given":"Ana Isabel","family":"Sousa","sequence":"first","affiliation":[{"name":"Department of Physics, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3842-2466","authenticated-orcid":false,"given":"Carlos","family":"Marques-Neves","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, University of Lisbon, 1649-028 Lisbon, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3823-1184","authenticated-orcid":false,"given":"Pedro Manuel","family":"Vieira","sequence":"additional","affiliation":[{"name":"Department of Physics, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,3,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1052","DOI":"10.1016\/S0196-0644(05)82750-7","article-title":"Evaluation and significance of the pupillary light reflex in trauma patients","volume":"22","author":"Meyer","year":"1993","journal-title":"Ann. 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