A Custom-made Pupillometer System for Characterizing Pupillary Light Response

Objectives:This paper presents the design and construction of a viable pupillometer system and demonstrates its merits with extensive validation tests.Materials and Methods:A web camera was modified by removing its infrared filter and mounted on a chin rest. Light emitting diodes (LEDs) operating at...

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Main Authors: Nefati Kıylıoğlu, Mahmut Alp Kılıç, Tolga Kocatürk, Seyhan Bahar Özkan, Mehmet Bilgen
Format: Article
Language:English
Published: Galenos Yayinevi 2018-08-01
Series:Türk Oftalmoloji Dergisi
Subjects:
Online Access: http://www.oftalmoloji.org/archives/archive-detail/article-preview/a-custom-made-pupillometer-system-for-characterizi/19564
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author Nefati Kıylıoğlu
Mahmut Alp Kılıç
Tolga Kocatürk
Seyhan Bahar Özkan
Mehmet Bilgen
author_facet Nefati Kıylıoğlu
Mahmut Alp Kılıç
Tolga Kocatürk
Seyhan Bahar Özkan
Mehmet Bilgen
author_sort Nefati Kıylıoğlu
collection DOAJ
description Objectives:This paper presents the design and construction of a viable pupillometer system and demonstrates its merits with extensive validation tests.Materials and Methods:A web camera was modified by removing its infrared filter and mounted on a chin rest. Light emitting diodes (LEDs) operating at infrared and visible spectra were integrated to provide background and light stimulus, respectively. The LEDs were controlled by a microprocessor board. Stimulation was presented using a periodic paradigm with variable period and duty cycle. Videos of both pupils were recorded at 30 frames/second and processed offline using software developed in-house. The overall system was validated with data gathered from individuals with healthy vision under different stimulation paradigms. Temporal variations in pupil size were determined and analyzed statistically.Results:The analysis revealed that the pupil sizes were accurately measured from the video frames provided that reflections from both infrared and visible lights remain outside the pupil. The system achieved moderate to excellent repeatability scores (87.8 and 86.8% for short 1 second and long 2 second pulses, respectively), which demonstrated its effectiveness and confirmed that it can be used reliably as a pupillometer.Conclusion:The proposed pupillometer system produces useful, quantitative data characterizing pupillary light response. However, further development and implementation are needed to potentially turn it into a low-cost alternative for other studies involving the autonomic nervous system, cognitive function, drug metabolism, pain response, psychology, fatigue, and sleep disorders.
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spelling doaj.art-0d8e6aa6fb1640e7a139bb669c3957af2023-02-15T16:11:11ZengGalenos YayineviTürk Oftalmoloji Dergisi1300-06592147-26612018-08-0148418518910.4274/tjo.3904913049054A Custom-made Pupillometer System for Characterizing Pupillary Light ResponseNefati Kıylıoğlu0Mahmut Alp Kılıç1Tolga Kocatürk2Seyhan Bahar Özkan3Mehmet Bilgen4 Adnan Menderes Üniversitesi Tıp Fakültesi, Nöroloji Anabilim Dalı, Klinik Nörofizyoloji Bilim Dalı, Aydın, Türkiye Adnan Menderes Üniversitesi Tıp Fakültesi, Nöroloji Anabilim Dalı, Klinik Nörofizyoloji Bilim Dalı, Aydın, Türkiye Adnan Menderes Üniversitesi Tıp Fakültesi, Göz Hastalıkları Anabilim Dalı, Aydın, Türkiye Adnan Menderes Üniversitesi Tıp Fakültesi, Göz Hastalıkları Anabilim Dalı, Aydın, Türkiye Adnan Menderes Üniversitesi Tıp Fakültesi, Biyofizik Anabilim Dalı, Aydın, Türkiye Objectives:This paper presents the design and construction of a viable pupillometer system and demonstrates its merits with extensive validation tests.Materials and Methods:A web camera was modified by removing its infrared filter and mounted on a chin rest. Light emitting diodes (LEDs) operating at infrared and visible spectra were integrated to provide background and light stimulus, respectively. The LEDs were controlled by a microprocessor board. Stimulation was presented using a periodic paradigm with variable period and duty cycle. Videos of both pupils were recorded at 30 frames/second and processed offline using software developed in-house. The overall system was validated with data gathered from individuals with healthy vision under different stimulation paradigms. Temporal variations in pupil size were determined and analyzed statistically.Results:The analysis revealed that the pupil sizes were accurately measured from the video frames provided that reflections from both infrared and visible lights remain outside the pupil. The system achieved moderate to excellent repeatability scores (87.8 and 86.8% for short 1 second and long 2 second pulses, respectively), which demonstrated its effectiveness and confirmed that it can be used reliably as a pupillometer.Conclusion:The proposed pupillometer system produces useful, quantitative data characterizing pupillary light response. However, further development and implementation are needed to potentially turn it into a low-cost alternative for other studies involving the autonomic nervous system, cognitive function, drug metabolism, pain response, psychology, fatigue, and sleep disorders. http://www.oftalmoloji.org/archives/archive-detail/article-preview/a-custom-made-pupillometer-system-for-characterizi/19564 Pupillary light reflexpupillary responsepupillometer
spellingShingle Nefati Kıylıoğlu
Mahmut Alp Kılıç
Tolga Kocatürk
Seyhan Bahar Özkan
Mehmet Bilgen
A Custom-made Pupillometer System for Characterizing Pupillary Light Response
Türk Oftalmoloji Dergisi
Pupillary light reflex
pupillary response
pupillometer
title A Custom-made Pupillometer System for Characterizing Pupillary Light Response
title_full A Custom-made Pupillometer System for Characterizing Pupillary Light Response
title_fullStr A Custom-made Pupillometer System for Characterizing Pupillary Light Response
title_full_unstemmed A Custom-made Pupillometer System for Characterizing Pupillary Light Response
title_short A Custom-made Pupillometer System for Characterizing Pupillary Light Response
title_sort custom made pupillometer system for characterizing pupillary light response
topic Pupillary light reflex
pupillary response
pupillometer
url http://www.oftalmoloji.org/archives/archive-detail/article-preview/a-custom-made-pupillometer-system-for-characterizi/19564
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