pupillary response
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2021 ◽  
Author(s):  
Carla Arévalo López ◽  
Samuel Madariaga Román ◽  
Ivan Plaza

Abstract Glaucoma is a multifactorial neurodegenerative disease of the optic nerve currently considered a severe health problem because of its high prevalence, being the primary cause of irreversible blindness worldwide. The most common type corresponds to Primary Open-Angle Glaucoma (POAG). Glaucoma produces, among other alterations, a progressive loss of Retinal Ganglion Cells (RGC) and its axons, key to generate the action potential that reaches the visual cortex to create the visual image. It indicates a Visual Field (VF) loss whose main feature is to be painless, and this makes early detection difficult, causing a late diagnosis and delaying a timely treatment indication that slows down its progression. Intrinsically photosensitive Retinal Ganglion Cells (ipRGCs), which represent a subgroup of RGCs being sensitive to damage, are characterized by reacting to short-wave light stimulation close to 480 nm and among their non-visual function, the role in the generation of the pupillary reflex stands out. Currently, the sensitivity of clinical trials correlates to RGC damage, however the need for an early damage biomarker is still relevant. It is an urgent task to create new diagnostic approaches to detect an early stage of glaucoma in a prompt, quick, and economical manner. We suggest evaluating the pupillary response to chromatic light as a potential biomarker of disease, its diagnostic benefit, and its cost-effectiveness in clinical practice to reduce irreversible damage caused by glaucoma.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261463
Author(s):  
Kyung Yoo ◽  
Jeongyeol Ahn ◽  
Sang-Hun Lee

Pupillometry, thanks to its strong relationship with cognitive factors and recent advancements in measuring techniques, has become popular among cognitive or neural scientists as a tool for studying the physiological processes involved in mental or neural processes. Despite this growing popularity of pupillometry, the methodological understanding of pupillometry is limited, especially regarding potential factors that may threaten pupillary measurements’ validity. Eye blinking can be a factor because it frequently occurs in a manner dependent on many cognitive components and induces a pulse-like pupillary change consisting of constriction and dilation with substantive magnitude and length. We set out to characterize the basic properties of this “blink-locked pupillary response (BPR),” including the shape and magnitude of BPR and their variability across subjects and blinks, as the first step of studying the confounding nature of eye blinking. Then, we demonstrated how the dependency of eye blinking on cognitive factors could confound, via BPR, the pupillary responses that are supposed to reflect the cognitive states of interest. By building a statistical model of how the confounding effects of eye blinking occur, we proposed a probabilistic-inference algorithm of de-confounding raw pupillary measurements and showed that the proposed algorithm selectively removed BPR and enhanced the statistical power of pupillometry experiments. Our findings call for attention to the presence and confounding nature of BPR in pupillometry. The algorithm we developed here can be used as an effective remedy for the confounding effects of BPR on pupillometry.


2021 ◽  
Author(s):  
Gunhild Falleth Sandvik ◽  
Svend Rand‐Hendriksen ◽  
Liv Drolsum ◽  
Olav Kristianslund

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kana Kuraguchi ◽  
Kei Kanari

AbstractIt is reported that women’s pupils dilate when they see a baby; it is unclear if this pupillary response is caused by the perception of cuteness itself. Since many objects besides babies can be perceived as cute, we investigated whether the perception of cuteness, or the type of object observed, is related to pupil dilation. In the first experiment, female participants were requested to rate the subjective cuteness of greyscale pictures of objects such as animals and foods; their pupil sizes were measured. The results showed a significant positive correlation between perceived cuteness and participants’ pupil dilation. In the second experiment, participants rated the cuteness of images of female faces. Results revealed a significant negative correlation between perceived cuteness and pupil dilation. In our study, perceiving cuteness enlarged female observers’ pupils except when observing female faces. Positive reactions associated with cuteness may be premised on the existence of unconscious perceptual alterations and physical responses.


2021 ◽  
Vol 15 (5) ◽  
pp. 391-402
Author(s):  
Bethânya G. Carizio ◽  
Gustavo A. Silva ◽  
Gabriel P. Paschoalino ◽  
Juliana C. De Angelo ◽  
Gisele C. Gotardi ◽  
...  

BACKGROUND: Cognitive workload resulting from drivers’ engagement in concomitant tasks while driving, such as talking on a cell phone, affects the availability of attentional resources for the various stages of information processing, which can interfere with the selection of relevant traffic information, leading to poor performance and higher risk of accidents. AIM: The purpose of this study was to test the adaptation and application of the method of fixation-aligned pupillary response averaging to the car driving context, and, if successful, to determine effects of talking on a cell phone while driving, in both handheld and hands-free situations, and effects of driving experience on pupillary responses of young adult drivers, as indicative of cognitive workload. METHOD: Ten novice and ten experienced drivers had pupil diameter measured while driving in a car simulator under velocity of 80-120 km/h, daylight, linear trajectory and low traffic level. Data analysis was based on the method of fixation-aligned pupillary response averaging. RESULTS: Noise curves were around baseline (zero) values while pupil dilation curves clearly stood out from noise magnitude, in all conditions for both groups. Greater pupil dilation peak during talking on the cell phone (handheld and hands-free conditions) while driving occurred only for the novice group. CONCLUSION: Adaptation and application of the method of fixation-aligned pupillary response averaging to the car driving context succeed. Cognitive workload imposed by the dual task of talking on a cell phone increased pupil dilation for novice drivers, which may alter acquisition of visual information and impair driving behavior.


2021 ◽  
pp. 000313482110540
Author(s):  
Zachary T. Thier ◽  
Kelan Drake-Lavelle ◽  
Phillip J. Prest ◽  
Mark A. Jones ◽  
Jeremy M. Reeves ◽  
...  

Introduction Chemical prophylaxis using low-molecular-weight heparin (LMWH) is considered a standard of care for venous thromboembolism in trauma patients. Our center performs a head computed tomography (CT) scan 24 hours after initiation with prophylactic LMWH in the setting of a known traumatic brain injury (TBI). The purpose was to determine the overall incidence of ICH progression after chemoprophylaxis in patients with a TBI. Methods This retrospective study was performed at a Level I trauma center, from 1/1/2014 to 12/31/2017. Study patients were drawn from the institution’s trauma registry based on Abbreviated Injury Score codes. Results 778 patients met all inclusion criteria after initial chart review. The proportion of patients with an observed radiographic progression of intracranial hemorrhage after LMWH was 5.8%. 3.1% of patients had a change in clinical management. Observed radiographic progression after LMWH prophylaxis and the presence of SDH on initial CT, the bilateral absence of pupillary response in the emergency department, and a diagnosis of dementia were found to have statistically significant correlation with bleed progression after LMWH was initiated. Conclusion Over a 4-year period, the use of CT to evaluate for radiographic progression of traumatic intracranial hemorrhage 24 hours after receiving LMWH resulted in a change in clinical management for 3.1% of patients. The odds of intracranial hemorrhage progression were approximately 6.5× greater in patients with subdural hemorrhage on initial CT, 3.1× greater in patients with lack of bilateral pupillary response in ED, and 4.2× greater in patients who had been diagnosed with dementia.


2021 ◽  
pp. 140-142
Author(s):  
Kamal Shouman ◽  
Eduardo E. Benarroch

A 65-year-old woman with a history of Graves disease, status post radioactive iodine therapy, and a biopsy-proven benign calcified breast nodule sought care for evaluation of multiple symptoms. She had constipation for 8 years, with prior fecal urgency, and intermittent diarrhea for the previous year. She was diagnosed with irritable bowel syndrome. Her weight remained stable until 1 1/2 years earlier, and she had lost 6.8 kg. For the previous 3 years, the patient had experienced multiple urinary symptoms including hesitancy, urgency, incontinence, and retention. She was diagnosed with a cystocele, the correction of which did not help. She had noted difficulty focusing her eyes when moving from a dark to a well-lit environment, or vice versa. She also reported orthostatic light-headedness for 1½years, which worsened on exposure to a hot environment. Neurologic examination showed abnormally dilated pupils with prominently sluggish constriction in response to light. Autonomic reflex screening indicated patchy postganglionic sympathetic sudomotor, marked cardiovagal, and cardiovascular adrenergic failure, with neurogenic orthostatic hypotension. Thermoregulatory sweat testing showed 82% anhidrosis. A nuclear medicine gastric-emptying study indicated delayed gastric emptying and colonic hypomotility. Serum testing was markedly positive for ganglionic (alpha 3) acetylcholine receptor autoantibodies. The patient was diagnosed with autoimmune autonomic ganglionopathy. The patient received intravenous immunoglobulin. She returned and reported 80% improvement in all symptoms, and neurologic examination showed normal pupillary response to light. Autonomic reflex screening indicated improvement of her adrenergic function, and thermoregulatory sweat testing showed an impressive improvement of her sudomotor function. Her postganglionic sympathetic sudomotor and cardiovagal function remained impaired. Gastric emptying remained mildly delayed. She was maintained on intravenous immunoglobulin, which was later tapered after azathioprine was started. Autoimmune autonomic ganglionopathy usually presents subacutely, much like other autoimmune neurologic diseases. Typical features of this disorder are the impaired pupillary reaction to light and prominent sicca symptoms, indicating prominent cranial parasympathetic (cholinergic) impairment. Also consistent with this diagnosis are the prominent gastrointestinal tract symptoms. Prominent cholinergic failure helps distinguish autoimmune autonomic ganglionopathy from peripheral autonomic neuropathy or neurodegenerative disorders such as pure autonomic failure.


PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258490
Author(s):  
Serena Castellotti ◽  
Lisa Scipioni ◽  
Stefano Mastandrea ◽  
Maria Michela Del Viva

Motion can be perceived in static images, such as photos and figurative paintings, representing realistic subjects in motion, with or without directional information (e.g., motion blur or speed lines). Motion impression can be achieved even in non-realistic static images such as motion illusions and abstract paintings. It has been shown that visual motion processing affects the diameter of the pupil, responding differently to real, illusory, and implied motion in photographs (IM). It has been suggested that these different effects might be due to top-down modulations from different cortical areas underlying their processing. It is worthwhile to investigate pupillary response to figurative paintings, since they require an even higher level of interpretation than photos representing the same kind of subjects, given the complexity of cognitive processes involved in the aesthetic experience. Also, pupil responses to abstract paintings allows to study the effect of IM perception in representations devoid of real-life motion cues. We measured pupil responses to IM in figurative and abstract artworks depicting static and dynamic scenes, as rated by a large group of individuals not participating in the following experiment. Since the pupillary response is modulated by the subjective image interpretation, a motion rating test has been used to correct individual pupil data according to whether participants actually perceived the presence of motion in the paintings. Pupil responses to movies showing figurative and abstract subjects, and to motion illusions were also measured, to compare real and illusory motion with painted IM. Movies, both figurative and abstract, elicit the largest pupillary dilation of all static stimuli, whereas motion illusions cause the smallest pupil size, as previously shown. Interestingly, pupil responses to IM depend on the paintings’ style. Figurative paintings depicting moving subjects cause more dilation than those representing static figures, and pupil size increases with the strength of IM, as already found with realistic photos. The opposite effect is obtained with abstract artworks. Abstract paintings depicting motion produce less dilation than those depicting stillness. In any case, these results reflect the individual subjective perception of dynamism, as the very same paintings can induce opposite responses in observer which interpreted it as static or dynamic. Overall, our data show that pupil size depends on high-level interpretation of motion in paintings, even when they do not represent real-world scenes. Our findings further suggest that the pupil is modulated by multiple top-down cortical mechanisms, involving the processing of motion, attention, memory, imagination, and other cognitive functions necessary for enjoying a complete aesthetic experience.


2021 ◽  
pp. 215-220

Background: Objective quantification of pupillary dynamics in a clinical setting is of worth importance to rule out any pupillary abnormalities. However, despite normal binocular vision findings, a quantitative measurement of pupillary response and accommodation provides a better insight to understand the mechanism. Case Report: This case report illustrates the clinical presentation, binocular vision parameters, Pupillary dynamics and accommodative response in a 33-year-old diagnosed with Adie’s Tonic pupil following trauma. Conclusion: This report explains the role of the pupillometer and open field autorefractor in quantitative analysis of pupillary and accommodative function.


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