A haploscope based binocular pupillometer system to quantify the dynamics of direct and consensual Pupillary Light Reflex

Meethal, Najiya Sundus Kadavath; Mazumdar, Deepmala; Morshchavka, Sergii; Robben, Jasper; Steen, J. van der; George, Ronnie; Pel, J.J.M.

doi:10.1038/s41598-021-00434-z

Cited by 4 publications

(2 citation statements)

References 36 publications

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“…Only a few studies used pupillometry specifically to assess ON patients [18,[22][23][24][25]. Given the strict connection between ON and MS, sometimes they were studied in concomitance [18,23,26,27].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Pupillary Light Response Features for the Classification of Patients with Optic Neuritis

et al. 2023

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Pupillometry is a promising technique for the potential diagnosis of several neurological pathologies. However, its potential is not fully explored yet, especially for prediction purposes and results interpretation. In this work, we analyzed 100 pupillometric curves obtained by 12 subjects, applying both advanced signal processing techniques and physics methods to extract typically collected features and newly proposed ones. We used machine learning techniques for the classification of Optic Neuritis (ON) vs. Healthy subjects, controlling for overfitting and ranking the features by random permutation, following their importance in prediction. All the extracted features, except one, turned out to have significant importance for prediction, with an average accuracy of 76%, showing the complexity of the processes involved in the pupillary light response. Furthermore, we provided a possible neurological interpretation of this new set of pupillometry features in relation to ON vs. Healthy classification.

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Section: Introductionmentioning

confidence: 99%

Characterization of Pupillary Light Response Features for the Classification of Patients with Optic Neuritis

et al. 2023

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“…The "swinging flashlight test" for example is a well-known procedure in neuro-ophthalmology in which the examiner, by swinging a penlight back and forth between the two eyes, tries to detect a difference in the amount of the dilation between the two pupils. The swinging flashlight test is a tool for measuring relative afferent pupillary defect, a condition of many retinal or optical nerve diseases [7][8][9][10]. Anisocoria which is the difference of the two diameters of the pupils at rest, is another expression of asymmetry often associated to intracranial pathologies [11].…”

Section: Introductionmentioning

confidence: 99%

A differential of the left eye and right eye neurological pupil index is associated with discharge modified Rankin scores in neurologically injured patients

Privitera

Neerukonda²,

Aiyagari³

et al. 2022

BMC Neurol

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Background Automated infrared pupillometry (AIP) and the Neurological Pupil index (NPi) provide an objective means of assessing and trending the pupillary light reflex (PLR) across a broad spectrum of neurological diseases. NPi quantifies the PLR and ranges from 0 to 5; in healthy individuals, the NPi of both eyes is expected to be ≥ 3.0 and symmetric. AIP values demonstrate emerging value as a prognostic tool with predictive properties that could allow practitioners to anticipate neurological deterioration and recovery. The presence of an NPi differential (a difference ≥ 0.7 between the left and right eye) is a potential sign of neurological abnormality. Methods We explored NPi differential by considering the modified Rankin Score at discharge (DC mRS) among patients admitted to neuroscience intensive care units (NSICU) of 4 U.S. and 1 Japanese hospitals and for two cohorts of brain injuries: stroke (including subarachnoid hemorrhage, intracerebral hemorrhage, acute ischemic stroke, and aneurysm, 1,200 total patients) and 185 traumatic brain injury (TBI) patients for a total of more than 54,000 pupillary measurements. Results Stroke patients with at least 1 occurrence of an NPi differential during their NSICU stay have higher DC mRS scores (3.9) compared to those without an NPi differential (2.7; P < .001). Patients with TBI and at least 1 occurrence of an NPi differential during their NSICU stay have higher discharge modified Rankin Scale scores (4.1) compared to those without an NPi differential (2.9; P < .001). When patients experience both abnormalities, abnormal (NPi < 3.0) and an NPi differential, the latter has an anticipatory relationship with respect to the former (P < .001 for z-score skewness analysis). Finally, our analysis confirmed ≥ 0.7 as the optimal cutoff value for the NPi differential (AUC = 0.71, P < .001). Conclusion The NPi differential is an important factor that clinicians should consider when managing critically ill neurological injured patients admitted to the neurocritical care units. Trial registration NCT02804438, Date of Registration: June 17, 2016.

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Touchless short-wave infrared imaging for dynamic rapid pupillometry and gaze estimation in closed eyes

Ben Barak-Dror,

Hadad,

Barhum

et al. 2024

Commun Med

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Background Assessments of gaze direction (eye movements), pupil size, and the pupillary light reflex (PLR) are critical for neurological examination and neuroscience research and constitute a powerful tool in diverse clinical settings ranging from critical care through endocrinology and drug addiction to cardiology and psychiatry. However, current bedside pupillometry is typically intermittent, qualitative, manual, and limited to open-eye cases, restricting its use in sleep medicine, anesthesia, and intensive care. Methods We combined short-wave infrared (SWIR, ~0.9-1.7μm) imaging with image processing algorithms to perform rapid (~30 ms) pupillometry and eye tracking behind closed eyelids. Forty-three healthy volunteers participated in two experiments with PLR evoked by visible light stimuli or directing eye movements towards screen targets. Imaging was performed simultaneously on one eye closed, and the other open eye serving as ground truth. Data analysis was performed with a custom approach quantifying changes in brightness around the pupil area or with a deep learning U-NET-based procedure. Results Here we show that analysis of SWIR imaging data can successfully measure stimulus-evoked PLR in closed-eye conditions, revealing PLR events in single trials and significant PLRs in nearly all individual subjects, as well as estimating gaze direction. The neural net-based analysis could successfully use closed-eye SWIR data to recreate estimates of open-eye images and assess pupil size. Conclusions Continuous touchless monitoring of rapid dynamics in pupil size and gaze direction through closed eyes paves the way for developing devices with wide-ranging applications, fulfilling long-standing goals in clinical and research fields.

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A haploscope based binocular pupillometer system to quantify the dynamics of direct and consensual Pupillary Light Reflex

Cited by 4 publications

References 36 publications

Characterization of Pupillary Light Response Features for the Classification of Patients with Optic Neuritis

Characterization of Pupillary Light Response Features for the Classification of Patients with Optic Neuritis

A differential of the left eye and right eye neurological pupil index is associated with discharge modified Rankin scores in neurologically injured patients

Touchless short-wave infrared imaging for dynamic rapid pupillometry and gaze estimation in closed eyes

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