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Philibert M, Milea D. Basics, benefits, and pitfalls of pupillometers assessing visual function. Eye (Lond) 2024; 38:2415-2421. [PMID: 38802485 PMCID: PMC11306737 DOI: 10.1038/s41433-024-03151-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 04/22/2024] [Accepted: 05/17/2024] [Indexed: 05/29/2024] Open
Abstract
Numerous commercially and non-commercially available pupillometers are nowadays able to assess various biological functions in humans, by evaluating pupils' dynamics in response to specific stimuli. However, the use of pupillometers for ophthalmic afferent evaluations (i.e., photoreceptoral responses) in real-world settings is relatively limited. Recent scientific and technological advances, coupled with artificial intelligence methods have improved the performance of such devices to objectively detect, quantify, and classify functional disturbances of the retina and the optic nerve. This review aims to summarize the scientific principles, indications, outcomes, and current limitations of pupillometry used for evaluation of afferent pathways in ophthalmic clinical settings.
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Affiliation(s)
| | - Dan Milea
- Rothschild Foundation Hospital, Paris, France.
- Copenhagen University Hospital, Copenhagen, Denmark.
- Singapore National Eye Centre, Singapore, Singapore.
- Angers University Hospital, Angers, France.
- Duke-NUS Medical School, Singapore, Singapore.
- Singapore Eye Research Institute, Singapore, Singapore.
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Kursawe M, Ehrlichmann H, Weber W, Krabbe J, Kraus T. Pain-induced effects on the pupillary light response under high and low illumination conditions. Front Neurol 2024; 15:1432638. [PMID: 39045429 PMCID: PMC11263288 DOI: 10.3389/fneur.2024.1432638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 06/14/2024] [Indexed: 07/25/2024] Open
Abstract
Objective The present study investigated the impact of two different light intensities on the pain-modulated pupillary light response (PLR). Additionally, it aimed to demonstrate parasympathetic and sympathetic influences on PLR parameters in response to pain, as predicted by functional models. Method A total of 24 participants were included in a randomized, repeated-measures design. The PLR was measured in response to both dark and bright light stimuli within two test cycles. Pain was induced using the cold pressor test (CPT), which involved immersing participants' feet in ice water. PLR measurements were taken during baseline and ice-water immersion within each test cycle. The assessed PLR parameters included initial diameter (INIT), latency (LAT), amplitude (AMP), and re-dilation time (ReDIL25). Along with these parameters, heart rate (HR) and pain ratings were also computed and analyzed. Main results The CPT caused moderate pain in participants, and the resulting PLR parameters were found to be congruent with the expected parasympathetic and sympathetic nervous system activities. Although the luminance of the stimulus did influence PLR parameters, no interaction with pain exposure was found. Significance The results showed that different aspects of pain experienced by an individual, as modulated through the sympathetic and parasympathetic nervous systems, are visible in their pupillary reactions to light. Notably, within the range used in the current study, light intensity did not significantly affect the pain-related PLR effects.
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Affiliation(s)
- Michael Kursawe
- Institute for Occupational, Social, and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany
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Ali AMS, Gul W, Sen J, Hewitt SJ, Olubajo F, McMahon C. Evaluating the utility of quantitative pupillometry in a neuro-critical care setting for the monitoring of intracranial pressure: A prospective cohort study. Clin Neurol Neurosurg 2024; 239:108215. [PMID: 38447480 DOI: 10.1016/j.clineuro.2024.108215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/26/2024] [Accepted: 02/28/2024] [Indexed: 03/08/2024]
Abstract
INTRODUCTION Assessment of the pupillary light reflex (PLR) is key in intensive care monitoring of neurosurgical patients, particularly for monitoring intracranial pressure (ICP). Quantitative pupillometry using a handheld pupillometer is a reliable method for PLR assessment. However, many variables are derived from such devices. We therefore aimed to assess the performance of these variables at monitoring ICP. METHODS Sedated patients admitted to neurocritical care in a tertiary neurosurgical centre with invasive ICP monitoring were included. Hourly measurement of ICP, subjective pupillometry (SP) using a pen torch device, and quantitative pupillometry (QP) using a handheld pupillometer were performed. RESULTS 561 paired ICP, SP and QP pupillary observations from nine patients were obtained (1122 total pupillary observations). SP and QP had a moderate concordance for pupillary size (κ=0.62). SP performed poorly at detecting pupillary size changes (sensitivity=24%). In 40 (3.6%) observations, SP failed to detect a pupillary response whereas QP did. Moderate correlations with ICP were detected for maximum constriction velocity (MCV), dilation velocity (DV), and percentage change in pupillary diameter (%C). Discriminatory ability at an ICP threshold of >22 mmHg was moderate for MCV (AUC=0.631), DV (AUC=0.616), %C (AUC=0.602), and pupillary maximum size (AUC=0.625). CONCLUSION QP is superior to SP at monitoring pupillary reactivity and changes to pupillary size. Although effect sizes were moderate to weak across assessed variables, our data indicates MCV and %C as the most sensitive variables for monitoring ICP. Further study is required to validate these findings and to establish normal range cut-offs for clinical use.
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Affiliation(s)
- Ahmad M S Ali
- Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK.
| | - Wisha Gul
- St Helens and Knowsley NHS Foundation Trust, Prescot, UK
| | - Jon Sen
- School of Medicine, Keele University, Newcastle-under-Lyme, UK
| | - Sarah-Jane Hewitt
- Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK
| | - Farouk Olubajo
- Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK
| | - Catherine McMahon
- Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK
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Negi R, Raviselvan M, Yarravarapu D, Chillakala K, Durai CVR, Baskar J, Jain A, Bisht K, Bhate M, Bharadwaj SR. Effect of Light Intensity on the Relative Afferent Pupillary Defect in Unilateral Neuro-ophthalmic Pathology. Optom Vis Sci 2023; 100:614-624. [PMID: 37639694 DOI: 10.1097/opx.0000000000002061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023] Open
Abstract
SIGNIFICANCE Objective pupillometry with standardized light intensities allows a comprehensive assessment of the relative afferent pupillary defect in patients with unilateral neuro-ophthalmic pathology. PURPOSE This study aimed to determine the impact of varying light intensities on the grade of relative afferent pupillary defect in unilateral neuro-ophthalmic pathology vis-à-vis healthy controls. METHODS Monocular pupillary light reflexes of 20 controls (14 to 50 years) and 31 cases (12 to 72 years) with clinically diagnosed relative afferent pupillary defect were measured thrice using 1-second-long light pulses, followed by 3 seconds of darkness, at eight light intensities (6.4 to 1200 lux) using objective pupillometry. The relative afferent pupillary defect was quantified as the ratio of the percentage change in the direct light reflexes of the left and right eyes. Its change with light intensity was described using standard exponential fits. RESULTS The median (25th to 75th interquartile range) defect score of 54.8% cases decreased from baseline values of 1.58 (1.25 to 1.87) for right eye pathology and 0.45 (0.39 to 0.55) for left eye pathology to saturation values of 1.18 (1.05 to 1.31) and 0.98 (0.95 to 1.06), respectively, at light intensities between 56.9 and 300.5 lux. Like controls (1.01 [1.00 to 1.06]), the defect scores of the remaining 45.2% cases were constant with light intensity at 1.23 (1.18 to 1.46) and 0.87 (0.86 to 0.89) for right and left eye pathologies, respectively. CONCLUSIONS Relative afferent pupillary defects may decrease with test light intensity in a significant proportion of patients with unilateral neuro-ophthalmic pathology. This highlights the importance of objective pupillometry with standardization light intensities for clinical assessment of afferent pupillary defects.
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Affiliation(s)
| | | | - Divyank Yarravarapu
- Centre for Technology Innovation, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | | | | | - Juhi Baskar
- Centre for Technology Innovation, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Ashish Jain
- Centre for Technology Innovation, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Karan Bisht
- Centre for Technology Innovation, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Manjushree Bhate
- Jasti V. Ramanamma Children's Eye Care Centre, Child Sight Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
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Orduna-Hospital E, Munarriz-Escribano M, Sanchez-Cano A. Visual Quality, Motility Behavior, and Retinal Changes Associated with Reading Tasks Performed on Electronic Devices. Life (Basel) 2023; 13:1777. [PMID: 37629634 PMCID: PMC10455831 DOI: 10.3390/life13081777] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/12/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
BACKGROUND The purpose of this study was to objectively evaluate visual discomfort using an eye tracker and aberrometer after a 21-min reading session on an iPad and an Ebook. Additionally, retinal changes were analyzed using optical coherence tomography (OCT). METHODS A total of 31 young subjects (24 ± 4 years) participated in this study. They read for 21 min on an Ebook and for another 21 min on an iPad under controlled lighting conditions while their eye movements were monitored using an eye tracker. Aberrometry and retinal OCT measurements were taken before and after each reading session. Parameters such as pupil diameter, fixations, saccades, blinks, total aberration, high-order aberration, low-order aberration, and central and peripheral retinal thickness in the nine early treatment diabetic retinopathy study (ETDRS) areas were measured for each reading situation. Statistical analysis was performed on the collected data. RESULTS No statistically significant differences (p > 0.05) between the two devices were observed in terms of the different types of eye movements or the changes in retinal thickness. However, the aberrometric analysis showed variations in post-reading situations depending on the device used. CONCLUSION Reading speed and visual discomfort resulting from electronic device usage can be objectively assessed using an eye tracker and aberrometer. Additionally, changes found in central and peripheral retinal thickness between the two devices and the baseline measurements were not significant and remained relatively stable.
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Affiliation(s)
| | | | - Ana Sanchez-Cano
- Department of Applied Physics, University of Zaragoza, 50009 Zaragoza, Spain;
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Kirk C, Childs C. Combat Sports as a Model for Measuring the Effects of Repeated Head Impacts on Autonomic Brain Function: A Brief Report of Pilot Data. Vision (Basel) 2023; 7:vision7020039. [PMID: 37218957 DOI: 10.3390/vision7020039] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/12/2023] [Accepted: 04/29/2023] [Indexed: 05/24/2023] Open
Abstract
Automated pupil light reflex (PLR) is a valid indicator of dysfunctional autonomic brain function following traumatic brain injury. PLR's use in identifying disturbed autonomic brain function following repeated head impacts without outwardly visible symptoms has not yet been examined. As a combat sport featuring repeated 'sub-concussive' head impacts, mixed martial arts (MMA) sparring may provide a model to understand such changes. The aim of this pilot study was to explore which, if any, PLR variables are affected by MMA sparring. A cohort of n = 7 MMA athletes (age = 24 ± 3 years; mass = 76.5 ± 9 kg; stature = 176.4 ± 8.5 cm) took part in their regular sparring sessions (eight rounds × 3 min: 1 min recovery). PLR of both eyes was measured immediately pre- and post-sparring using a Neuroptic NPi-200. Bayesian paired samples t-tests (BF10 ≥ 3) revealed decreased maximum pupil size (BF10 = 3), decreased minimum pupil size (BF10 = 4) and reduced PLR latency (BF10 = 3) post-sparring. Anisocoria was present prior to sparring and increased post-sparring, with both eyes having different minimum and maximum pupil sizes (BF10 = 3-4) and constriction velocities post-sparring (BF10 = 3). These pilot data suggest repeated head impacts may cause disturbances to autonomic brain function in the absence of outwardly visible symptoms. These results provide direction for cohort-controlled studies to formally investigate the potential changes observed.
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Affiliation(s)
- Christopher Kirk
- Health Research Institute, Sheffield Hallam University, Sheffield S10 2NA, UK
| | - Charmaine Childs
- Health Research Institute, Sheffield Hallam University, Sheffield S10 2NA, UK
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Decleva D, Vidal KS, Kreuz AC, de Menezes PAHL, Ventura DF. Alterations of color vision and pupillary light responses in age-related macular degeneration. Front Aging Neurosci 2023; 14:933453. [PMID: 36688155 PMCID: PMC9849391 DOI: 10.3389/fnagi.2022.933453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 11/24/2022] [Indexed: 01/06/2023] Open
Abstract
Introduction Age-related macular degeneration (AMD) is the leading cause of irreversible central vision loss in developed countries and one of the leading causes of blindness. In this work, we evaluated color vision and the pupil light reflex (PLR) to assess visual function in patients with early and neovascular AMD (NVAMD) compared with the control group. Methods We recruited 34 early patients with dry AMD and classified them into two groups following AREDS: 13 patients with NVAMD and 24 healthy controls. Controls and patients with early dry AMD had visual acuity (VA) best or equal to 20/25 (0.098 logMAR). Color vision was assessed in controls and patients with early dry AMD using the Cambridge Color Test (CCT) 2.0 through the Trivector protocol. The PLR was evaluated using a Ganzfeld, controlled by the RETI-port system. The stimuli consisted of 1s blue (470 nm) and red (631 nm) light flashes presented alternately at 2-min intervals. To assess the cone contribution, we used a red flash at 2.4 log cd.m-2, with a blue background at 0.78 log cd.m-2. For rods, we used 470-nm flashes at -3 log cd.m-2, and for the melanopsin function of ipRGCs, we used 470 nm at 2.4 log cd.m-2. Results Patients with early dry AMD had reduced color discrimination in all three axes: protan (p = 0.0087), deutan (p = 0.0180), and tritan (p = 0.0095) when compared with the control group. The PLR has also been affected in patients with early dry AMD and patients with NVAMD. The amplitude for the melanopsin-driven response was smaller in patients with early dry AMD (p = 0.0485) and NVAMD (p = 0.0035) than in the control group. The melanopsin function was lower in patients with NVAMD (p = 0.0290) than the control group. For the rod-driven response, the latency was lower in the NVAMD group (p = 0.0041) than in the control group. No changes were found in cone-driven responses between the control and AMD groups. Conclusion Patients with early dry AMD present diffusely acquired color vision alteration detected by CCT. Rods and melanopsin contributions for PLR are affected in NVAMD. The CCT and the PLR may be considered sensitive tests to evaluate and monitor functional changes in patients with AMD.
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Affiliation(s)
- Diego Decleva
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo, São Paulo, Brazil,Neuroscience and Behavior Graduate Studies Program, Institute of Psychology, University of São Paulo, São Paulo, Brazil,*Correspondence: Diego Decleva,
| | - Kallene Summer Vidal
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo, São Paulo, Brazil,Prevent Senior Health Operator, São Paulo, Brazil,Service of Interdisciplinary Neuromodulation, Laboratory of Neurosciences (LIM-27), Institute of Psychiatry, Medical School, University of São Paulo, São Paulo, Brazil,Young Medical Leadership Program of National Academy of Medicine in Brazil, Rio de Janeiro, Brazil
| | - Andre Carvalho Kreuz
- Neuroscience and Behavior Graduate Studies Program, Institute of Psychology, University of São Paulo, São Paulo, Brazil
| | | | - Dora Fix Ventura
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo, São Paulo, Brazil,Neuroscience and Behavior Graduate Studies Program, Institute of Psychology, University of São Paulo, São Paulo, Brazil
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Asakawa K, Imai M, Ohta M, Kawata N, Kawatsu N, Ishikawa H. Pupil assessment with a new handheld pupillometer in healthy subjects. Int Ophthalmol 2023; 43:51-61. [PMID: 35821362 DOI: 10.1007/s10792-022-02387-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/14/2022] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To assess the pupil response with a new handheld pupillometer in healthy subjects. METHODS Sixty-four eyes of 32 healthy subjects (mean age 21.2 years) were tested. After dark adaptation for 10 min, pupil responses to 1 s red and blue light stimuli at 100 cd/m2 were measured in the order from right to left eyes with a 1 min interval. The initial pupil size (D1, mm), minimum pupil size (D2, mm), and constriction rate (CR, %) were obtained. Intra-examiner reproducibility was examined using the coefficient of variation (CV, %) and the Bland-Altman plot. Inter-examiner consistency was examined using the interclass correlation coefficient (ICC) and the agreements with a conventional device, by Pearson's correlation coefficient (r). RESULTS The CV of all parameters have high reproducibility in the red (11.0-20.7%) and blue (5.5-12.1%) light stimuli. Bland-Altman plot analysis showed no bias with both light stimuli. "Almost perfect" and "substantial" correlations between the examiners were obtained in the red (ICC = 0.78-0.94) and blue (ICC = 0.71-0.89) light stimuli. "Excellent" and "good" correlations between the devices were obtained, except for the CR parameter in the red (D1: r = 0.90; p < 0.001, D2: 0.72; p < 0.001, and CR: 0.08; p = 0.631, respectively) and blue (D1: r = 0.87; p < 0.001, D2: 0.70; p < 0.001, and CR: 0.19; p = 0.274, respectively) light stimuli. CONCLUSION The novel pupillometer is useful for assessing pupil response. However, because of their different constructions, the CR values cannot be compared directly between the devices.
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Affiliation(s)
- Ken Asakawa
- Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan.
| | - Mei Imai
- Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Mizuki Ohta
- Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Naomi Kawata
- Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Nanako Kawatsu
- Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Hitoshi Ishikawa
- Department of Orthoptics and Visual Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
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Abstract
BACKGROUND Around 60%--75% of myasthenia gravis (MG) patients initially present with nonspecific ocular symptoms. Failed recognition of these symptoms may delay the diagnosis of MG up to 5 years or more, leading to a reduced likelihood of remission and increased morbidity. Current diagnostic tests are either poorly sensitive for patients presenting with ocular symptoms alone or are time consuming, invasive, require a high level of technical expertise, and generally are universally difficult to obtain. This review will explore quantitative eye and pupil tracking as a potential noninvasive, time-effective, and less technically demanding alternative to current diagnostic tests of MG. EVIDENCE ACQUISITION Comprehensive literature review. RESULTS Thirty-two publications using oculography for the diagnosis of MG and 6 studies using pupillometry were evaluated. In MG patients, extra ocular muscle fatigue was evident in reports of intersaccadic, intrasaccadic and postsaccadic abnormalities, changes in optokinetic nystagmus, slow eye movements, disconjugate saccades, and pupillary constrictor muscle weakness. CONCLUSIONS Our review identified several potentially useful variables that derive from oculography and pupillometry studies that could assist with a timely diagnosis of MG. Limitations of this review include heterogeneity in design, sample size, and quality of the studies evaluated. There is a need for larger, well-designed studies evaluating eye-tracking measures in the diagnosis of MG, especially for patients presenting with purely ocular symptoms.
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Różanowski K. New biomarkers for the assessment of fatigue evoked by long-term sleep deprivation based on pupillary light reflex using rheological models. Biocybern Biomed Eng 2022. [DOI: 10.1016/j.bbe.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Zandi B, Lode M, Herzog A, Sakas G, Khanh TQ. PupilEXT: Flexible Open-Source Platform for High-Resolution Pupillometry in Vision Research. Front Neurosci 2021; 15:676220. [PMID: 34220432 PMCID: PMC8249868 DOI: 10.3389/fnins.2021.676220] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 04/28/2021] [Indexed: 12/12/2022] Open
Abstract
The human pupil behavior has gained increased attention due to the discovery of the intrinsically photosensitive retinal ganglion cells and the afferent pupil control path's role as a biomarker for cognitive processes. Diameter changes in the range of 10-2 mm are of interest, requiring reliable and characterized measurement equipment to accurately detect neurocognitive effects on the pupil. Mostly commercial solutions are used as measurement devices in pupillometry which is associated with high investments. Moreover, commercial systems rely on closed software, restricting conclusions about the used pupil-tracking algorithms. Here, we developed an open-source pupillometry platform consisting of hardware and software competitive with high-end commercial stereo eye-tracking systems. Our goal was to make a professional remote pupil measurement pipeline for laboratory conditions accessible for everyone. This work's core outcome is an integrated cross-platform (macOS, Windows and Linux) pupillometry software called PupilEXT, featuring a user-friendly graphical interface covering the relevant requirements of professional pupil response research. We offer a selection of six state-of-the-art open-source pupil detection algorithms (Starburst, Swirski, ExCuSe, ElSe, PuRe and PuReST) to perform the pupil measurement. A developed 120-fps pupillometry demo system was able to achieve a calibration accuracy of 0.003 mm and an averaged temporal pupil measurement detection accuracy of 0.0059 mm in stereo mode. The PupilEXT software has extended features in pupil detection, measurement validation, image acquisition, data acquisition, offline pupil measurement, camera calibration, stereo vision, data visualization and system independence, all combined in a single open-source interface, available at https://github.com/openPupil/Open-PupilEXT.
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Affiliation(s)
- Babak Zandi
- Laboratory of Lighting Technology, Department of Electrical Engineering and Information Technology, Technical University of Darmstadt, Darmstadt, Germany
| | - Moritz Lode
- Laboratory of Lighting Technology, Department of Electrical Engineering and Information Technology, Technical University of Darmstadt, Darmstadt, Germany
| | - Alexander Herzog
- Laboratory of Lighting Technology, Department of Electrical Engineering and Information Technology, Technical University of Darmstadt, Darmstadt, Germany
| | - Georgios Sakas
- Interactive Graphic Systems, Department of Computer Science, Technical University of Darmstadt, Darmstadt, Germany
| | - Tran Quoc Khanh
- Laboratory of Lighting Technology, Department of Electrical Engineering and Information Technology, Technical University of Darmstadt, Darmstadt, Germany
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