An open-source, FireWire camera-based, Labview-controlled image acquisition system for automated, dynamic pupillometry and blink detection

Souza, John Kennedy Schettino de; Pinto, Marcos Antônio da Silva; Vieira, Pedro G.; Baron, Jerome; Tierra-Criollo, Carlos Júlio

doi:10.1016/j.cmpb.2013.07.011

Cited by 16 publications

(10 citation statements)

References 57 publications

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“…This hand-held device has been extensively tested in emergence medicine [16]. In addition, custom-built head-mounted or goggle-mounted PLR devices also have been reported in literature [17–19]. …”

Section: Introductionmentioning

confidence: 99%

rPLR: an imaging system for measuring pupillary light reflex at a distance

2014

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Pupillary light reflex (PLR) is a simple noninvasive neurological test that can reveal a great amount of information of the neural system. We report here a novel imaging system for measuring PLR without using any restraints to limit the subject’s movement. Our system incorporates a tracking component that can locate the subject’s eye position and redirect the pupillary imaging component to follow the subject’s movement. This system can measure PLR, at a distance from the subject, with high spatial resolution (<50 µm) and temporal resolution (120 Hz). Because this new PLR device can accommodate the subject’s movement, it is well positioned to test in young children and other people who have difficulty remaining voluntarily still during tests.

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Section: Introductionmentioning

confidence: 99%

rPLR: an imaging system for measuring pupillary light reflex at a distance

2014

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“…That research was mainly focused on the stimulus module. Another interesting monocular solution was shown in [12]. The system was based on a low cost FireWire camera.…”

Section: Introductionmentioning

confidence: 99%

System and measurement method for binocular pupillometry to study pupil size variability

et al. 2014

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BackgroundAn objective and noninvasive examination of pupil size variability can be used to assess the activity of the autonomous nervous system. We designed a system that enables binocular, fast, and accurate recordings of different types of pupil variabilities, which are synchronous with other biosignals. This type of measurement system is needed to extend the scope of pupillometry applications.MethodsIn the proposed system, the left and right eyes are independently and interchangeably illuminated to generate alternating images, which are successively acquired by a single camera. The system is composed of four functional modules: the image acquisition module, the image processing unit, the light stimulator, and the controller. The proposed image processing algorithm approximates the shape of the pupil using the best-fit ellipse. The user control panel (controller) precisely sets the stimuli parameters and controls the entire measurement procedure.ResultsThe computer-based binocular system records the pupil size during the pupil light reflexes (direct and indirect) and spontaneous pupil size fluctuations, at a sampling rate up to 75 Hz, with a resolution better than 0.02 mm. Our initial laboratory tests confirmed that the new system is fast and precise (system accuracy better than 0.5% and repeatability better than 4%).ConclusionsThe proposed system’s unique geometry and construction, and the method it uses to detect images from each eye, allows us to monitor the right and left eyes using a single camera with no overlap between the images. The system does not require a very experienced operator, because it is relatively simple and easy to use. Importantly, it is comfortable for the subjects. Additionally, the presented system can operate with other bio-measurement systems using a synchronous signal. These system capabilities can expand the scope of pupillometry research applications.

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“…There are several predefined parameters that may be used to describe PLR. Parameters determined using the F²D Fit-For-Duty device by AMTech are as follows: latency L describes the delay between a light pulse and the pupil reaction; duration of reaction DR is the time to reach minimal value diameter; time of minimum diameter TMD is the time for which diameter is less than 50% of the beginning value; 2/3 contraction interval 2/3CI is the time in which the amplitude reaches 1/3 of the value in contraction phase; 1/3 redilatation interval 1/3 RI represents the time in which the amplitude reaches 1/3 of the value in redilatation phase; and amplitude A describes the difference between the maximum and minimum value of the diameter [13][14][15].…”

Section: Implementation Of the Modelmentioning

confidence: 99%

Rheological model of dynamic pupillary reflex in the assessment of the level of autonomic nervous system activation

Różanowski¹,

Truszczyński²,

Lewandowski³

et al. 2016

WIT Transactions on Engineering Sciences

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The aim of this publication was to adapt a rheological model of Kelvin-Voigt in the description of the dynamic pupillary reflex. The pupillary reflex presents the results of physiological adaptation mechanisms in the human eye, i.e. response of the iris to the changing intensity of light falling on the retina under the condition of sensory deprivation. Pupillary light reflex (PLR) is a closed loop nerve reflex.The new approach to PLR evaluation presented by the authors consists of adapting the Kelvin-Voigt model to the description of this phenomenon. The authors, for their tests of correct implementation of the model, used data from pilot studies. Research was performed on a group of 10 volunteers in a laboratory environment, at night. The mean age of the study participants was 27 ± 0.4 years. For PLR registration, the F²D Fit-For-Duty system was used .The system provides useful data for shift work or for personnel in high-risk careers.The PLR measurements were taken for both eyes, which were exposed to a series of five flashes at 30-second intervals. The whole measurement of both eyes was conducted with patients wearing goggles, in order to maintain the same measurement conditions, mostly with regard to accommodation.Owing to proper implementation of the model, we managed to attain a high level of its adaptation to real data (>90%). The results show their strong correlation, and the model shows high sensitivity to changes in the shape of the reflex curve, caused by sleep deprivation introduced in the experiment.

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An open-source, FireWire camera-based, Labview-controlled image acquisition system for automated, dynamic pupillometry and blink detection

Cited by 16 publications

References 57 publications

rPLR: an imaging system for measuring pupillary light reflex at a distance

rPLR: an imaging system for measuring pupillary light reflex at a distance

System and measurement method for binocular pupillometry to study pupil size variability

Rheological model of dynamic pupillary reflex in the assessment of the level of autonomic nervous system activation

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