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Pupillary Light Reflex Induced by Two-Photon Vision

PURPOSE: Two-photon vision relies on the perception of pulsed infrared light due to two-photon absorption in visual pigments. This study aimed to measure human pupil reaction caused by a two-photon 1040-nm stimulus and compare it with pupil responses elicited by 520-nm stimuli of similar color. METH...

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Autores principales: Zielińska, Agnieszka, Ciąćka, Piotr, Szkulmowski, Maciej, Komar, Katarzyna
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Association for Research in Vision and Ophthalmology 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8711009/
https://www.ncbi.nlm.nih.gov/pubmed/34935882
http://dx.doi.org/10.1167/iovs.62.15.23
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author Zielińska, Agnieszka
Ciąćka, Piotr
Szkulmowski, Maciej
Komar, Katarzyna
author_facet Zielińska, Agnieszka
Ciąćka, Piotr
Szkulmowski, Maciej
Komar, Katarzyna
author_sort Zielińska, Agnieszka
collection PubMed
description PURPOSE: Two-photon vision relies on the perception of pulsed infrared light due to two-photon absorption in visual pigments. This study aimed to measure human pupil reaction caused by a two-photon 1040-nm stimulus and compare it with pupil responses elicited by 520-nm stimuli of similar color. METHODS: Pupillary light reflex (PLR) was induced on 14 dark-adapted healthy subjects. Three types of fovea-centered stimuli of 3.5° diameter were tested: spirals formed by fast scanning 1040-nm (infrared [IR] laser) or 520-nm (visible [VIS] laser) laser beams and uniformly filled circle created by 520-nm LED (VIS light-emitting diode [LED]). The power of visible stimuli was determined with a dedicated procedure to obtain the same perceived brightness equivalent as for 800 µW used for two-photon stimulation. RESULTS: The minimum pupil diameter for IR laser was 88% ± 10% of baseline, significantly larger than for both VIS stimuli: 74% ± 10% (laser) and 69% ± 9% (LED). Mean constriction velocity and time to maximum constriction had significantly smaller values for IR than for both VIS stimuli. Latency times were similar for IR and VIS lasers and slightly smaller for VIS LED. CONCLUSIONS: The two-photon stimulus caused a considerably weaker pupil reaction than one-photon stimuli of the same shape, brightness, and similar color. The smaller pupil response may be due to weaker two-photon stimulation of rods relative to cones as previously observed for two-photon vision. Contrary to normal vision, in a two-photon process the stray light is not perceived, which might reduce the number of stimulated photoreceptors and further weaken the PLR.
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spelling pubmed-87110092022-01-14 Pupillary Light Reflex Induced by Two-Photon Vision Zielińska, Agnieszka Ciąćka, Piotr Szkulmowski, Maciej Komar, Katarzyna Invest Ophthalmol Vis Sci Visual Neuroscience PURPOSE: Two-photon vision relies on the perception of pulsed infrared light due to two-photon absorption in visual pigments. This study aimed to measure human pupil reaction caused by a two-photon 1040-nm stimulus and compare it with pupil responses elicited by 520-nm stimuli of similar color. METHODS: Pupillary light reflex (PLR) was induced on 14 dark-adapted healthy subjects. Three types of fovea-centered stimuli of 3.5° diameter were tested: spirals formed by fast scanning 1040-nm (infrared [IR] laser) or 520-nm (visible [VIS] laser) laser beams and uniformly filled circle created by 520-nm LED (VIS light-emitting diode [LED]). The power of visible stimuli was determined with a dedicated procedure to obtain the same perceived brightness equivalent as for 800 µW used for two-photon stimulation. RESULTS: The minimum pupil diameter for IR laser was 88% ± 10% of baseline, significantly larger than for both VIS stimuli: 74% ± 10% (laser) and 69% ± 9% (LED). Mean constriction velocity and time to maximum constriction had significantly smaller values for IR than for both VIS stimuli. Latency times were similar for IR and VIS lasers and slightly smaller for VIS LED. CONCLUSIONS: The two-photon stimulus caused a considerably weaker pupil reaction than one-photon stimuli of the same shape, brightness, and similar color. The smaller pupil response may be due to weaker two-photon stimulation of rods relative to cones as previously observed for two-photon vision. Contrary to normal vision, in a two-photon process the stray light is not perceived, which might reduce the number of stimulated photoreceptors and further weaken the PLR. The Association for Research in Vision and Ophthalmology 2021-12-22 /pmc/articles/PMC8711009/ /pubmed/34935882 http://dx.doi.org/10.1167/iovs.62.15.23 Text en Copyright 2021 The Authors https://creativecommons.org/licenses/by/4.0/This work is licensed under a Creative Commons Attribution 4.0 International License.
spellingShingle Visual Neuroscience
Zielińska, Agnieszka
Ciąćka, Piotr
Szkulmowski, Maciej
Komar, Katarzyna
Pupillary Light Reflex Induced by Two-Photon Vision
title Pupillary Light Reflex Induced by Two-Photon Vision
title_full Pupillary Light Reflex Induced by Two-Photon Vision
title_fullStr Pupillary Light Reflex Induced by Two-Photon Vision
title_full_unstemmed Pupillary Light Reflex Induced by Two-Photon Vision
title_short Pupillary Light Reflex Induced by Two-Photon Vision
title_sort pupillary light reflex induced by two-photon vision
topic Visual Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8711009/
https://www.ncbi.nlm.nih.gov/pubmed/34935882
http://dx.doi.org/10.1167/iovs.62.15.23
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