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1.
Sensors (Basel) ; 21(21)2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34770410

RESUMO

Strong evidence from studies on primates and rodents shows that changes in pupil diameter may reflect neural activity in the locus coeruleus (LC). Pupillometry is the only available non-invasive technique that could be used as a reliable and easily accessible real-time biomarker of changes in the in vivo activity of the LC. However, the application of pupillometry to preclinical research in rodents is not yet fully standardized. A lack of consensus on the technical specifications of some of the components used for image recording or positioning of the animal and cameras have been recorded in recent scientific literature. In this study, a novel pupillometry system to indirectly assess, in real-time, the function of the LC in anesthetized rodents is presented. The system comprises a deep learning SOLOv2 instance-based fast segmentation framework and a platform designed to place the experimental subject, the video cameras for data acquisition, and the light source. The performance of the proposed setup was assessed and compared to other baseline methods using a validation and an external test set. In the latter, the calculated intersection over the union was 0.93 and the mean absolute percentage error was 1.89% for the selected method. The Bland-Altman analysis depicted an excellent agreement. The results confirmed a high accuracy that makes the system suitable for real-time pupil size tracking, regardless of the pupil's size, light intensity, or any features typical of the recording process in sedated mice. The framework could be used in any neurophysiological study with sedated or fixed-head animals.


Assuntos
Aprendizado Profundo , Locus Cerúleo , Animais , Luz , Camundongos , Pupila
2.
PLoS One ; 16(10): e0258490, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34634092

RESUMO

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.


Assuntos
Pinturas , Pupila/fisiologia
3.
PLoS One ; 16(10): e0258390, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34673784

RESUMO

In the light of an increased use of premium intraocular lenses (IOL), such as EDOF IOLs, multifocal IOLs or toric IOLs even minor intraoperative complications such as decentrations or an IOL tilt, will hamper the visual performance of these IOLs. Thus, the post-operative analysis of cataract surgeries to detect even minor intraoperative deviations that might explain a lack of a post-operative success becomes more and more important. Up-to-now surgical videos are evaluated by just looking at a very limited number of intraoperative data sets, or as done in studies evaluating the pupil changes that occur during surgeries, in a small number intraoperative picture only. A continuous measurement of pupil changes over the whole surgery, that would achieve clinically more relevant data, has not yet been described. Therefore, the automatic retrieval of such events may be a great support for a post-operative analysis. This would be especially true if large data files could be evaluated automatically. In this work, we automatically detect pupil reactions in cataract surgery videos. We employ a Mask R-CNN architecture as a segmentation algorithm to segment the pupil and iris with pixel-based accuracy and then track their sizes across the entire video. We can detect pupil reactions with a harmonic mean (H) of Recall, Precision, and Ground Truth Coverage Rate (GTCR) of 60.9% and average prediction length (PL) of 18.93 seconds. However, we consider the best configuration for practical use the one with the H value of 59.4% and PL of 10.2 seconds, which is much shorter. We further investigate the generalization ability of this method on a slightly different dataset without retraining the model. In this evaluation, we achieve the H value of 49.3% with the PL of 18.15 seconds.


Assuntos
Extração de Catarata , Pupila , Lentes Intraoculares
4.
J Neurosci Nurs ; 53(6): 233-237, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34593723

RESUMO

ABSTRACT: BACKGROUND: Pupillary examinations provide early subtle signs of worsening intracranial pathology. Objective pupillomtery assessment, although not yet the standard of care, is considered best practice. However, inconsistent findings from objective pupillometry studies have caused a lack of consensus among clinicians; as such, no clinical guidelines are available to guide clinical use of objective pupillometer devices. To add to the body of evidence, the purpose of this project was to explore the relationship between objective pupillometry metrics and midline shift (MLS). METHODS: A retrospective chart review of pupillometer data was conducted. Midline shift was correlated with objective pupillometry metrics including Neurological Pupil Index (NPi), pupil size, and anisocoria. Midline shift was measured for the patient's initial neuroimaging and with any defined neurological change. Spearman ρ was used for statistical analysis of correlations between pupillometer metrics and MLS measured at both the septum pellucidum and pineal gland. RESULTS: A total of 41 patients were included in the analysis; most were White (58.5%) and male (58.5%), with a mean (SD) age of 58.49 (16.92) years. Spearman ρ revealed statistically significant positive correlations between right pupil NPi and anisocoria with MLS, and significant negative correlations between left pupil NPi and pupil size with MLS. CONCLUSIONS: Results from this project are consistent with previous studies. Objective pupillometry continues to be a valuable component of a comprehensive neurological examination, because it has the ability to discern early and subtle changes in a patient's neurological status, leading to lifesaving interventions.


Assuntos
Benchmarking , Reflexo Pupilar , Humanos , Masculino , Pessoa de Meia-Idade , Exame Neurológico , Pupila , Estudos Retrospectivos
5.
Eur J Neurosci ; 54(10): 7560-7574, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34716728

RESUMO

Pupil size reflects a proxy for neural activity associated with global luminance, arousal and cognitive processing. Microsaccades are also modulated by arousal and cognitive processing. Are these effects of arousal and cognitive signals on pupil size and microsaccades coordinated? If so, via what neural mechanisms? We hypothesized that if pupil size and microsaccades are coordinately modulated by these processes, pupil size immediately before microsaccade onset, as an index for ongoing cognitive and arousal processing, should correlate with microsaccade responses during tasks alternating these signals. Here, we examined the relationship between pupil size and microsaccade responses in tasks that included variations in global luminance, arousal and inhibitory control. Higher microsaccade peak velocities correlated with larger pre-microsaccade pupil response related to arousal and inhibitory control signals. In contrast, pupil responses evoked by global luminance signals did not correlate with microsaccade responses. Given the central role of the superior colliculus in microsaccade generation, these results suggest the critical involvement of the superior colliculus to coordinate pupil and microsaccade responses for arousal and inhibitory control modulations, but not for the pupil luminance modulation.


Assuntos
Fixação Ocular , Movimentos Sacádicos , Nível de Alerta , Cognição , Estimulação Luminosa , Pupila , Percepção Visual
6.
Nat Commun ; 12(1): 5944, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34642335

RESUMO

Although luminance is the main determinant of pupil size, the amplitude of the pupillary light response is also modulated by stimulus appearance and attention. Here we ask whether perceived numerosity modulates the pupillary light response. Participants passively observed arrays of black or white dots of matched physical luminance but different physical or illusory numerosity. In half the patterns, pairs of dots were connected by lines to create dumbbell-like shapes, inducing an illusory underestimation of perceived numerosity; in the other half, connectors were either displaced or removed. Constriction to white arrays and dilation to black were stronger for patterns with higher perceived numerosity, either physical or illusory, with the strength of the pupillary light response scaling with the perceived numerosity of the arrays. Our results show that even without an explicit task, numerosity modulates a simple automatic reflex, suggesting that numerosity is a spontaneously encoded visual feature.


Assuntos
Reconhecimento Visual de Modelos/fisiologia , Pupila/fisiologia , Reflexo Pupilar/fisiologia , Visão Ocular/fisiologia , Adulto , Feminino , Humanos , Ilusões , Luz , Masculino , Estimulação Luminosa/métodos
7.
Sensors (Basel) ; 21(20)2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34696060

RESUMO

Remote eye tracking technology has suffered an increasing growth in recent years due to its applicability in many research areas. In this paper, a video-oculography method based on convolutional neural networks (CNNs) for pupil center detection over webcam images is proposed. As the first contribution of this work and in order to train the model, a pupil center manual labeling procedure of a facial landmark dataset has been performed. The model has been tested over both real and synthetic databases and outperforms state-of-the-art methods, achieving pupil center estimation errors below the size of a constricted pupil in more than 95% of the images, while reducing computing time by a 8 factor. Results show the importance of use high quality training data and well-known architectures to achieve an outstanding performance.


Assuntos
Tecnologia de Rastreamento Ocular , Pupila , Bases de Dados Factuais , Redes Neurais de Computação
9.
Comput Inform Nurs ; 39(9): 499-507, 2021 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-34495011

RESUMO

High-fidelity clinical simulations can be used by clinicians to acquire technical (physical ability and knowledge) and non-technical (cognitive and social processes) skills. Excessive cognitive workload contributes to medical errors because of the impact on both technical and non-technical skills. Many studies measure cognitive workload with psychometric instruments that limit the assessment of cognitive workload to a single time period and may involve response bias. Using eye tracking to measure task-evoked pupillary responses allows the measurement of changes in pupil diameter related to the cognitive workload associated with a specific activity. Incorporating eye tracking with high-fidelity clinical simulations provides a reliable and continuous assessment of cognitive workload. The purpose of this literature review is to summarize the use of eye-tracking technology to measure cognitive workload of healthcare providers to generate evidence-based guidelines for measuring cognitive workload during high-fidelity clinical simulations. What this manuscript adds to the body of literature is a summary of best practices related to the different methods of measuring cognitive workload, benefits and limitations of using eye tracking, and high-fidelity clinical simulation design considerations for successful integration of eye tracking.


Assuntos
Movimentos Oculares , Tecnologia de Rastreamento Ocular , Cognição , Humanos , Pupila , Carga de Trabalho
10.
Neurosci Biobehav Rev ; 130: 351-368, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34499928

RESUMO

The use of pupillometry to track emotional learning processes in humans is generating an increasing interest. Here, we provide a first systematic review and meta-analysis on the value of pupil dilation as a marker of Pavlovian conditioning, focusing on the roles of UCS valence (aversive vs. appetitive), the time course across trials and response intervals within trials. Based on data from 39 independent samples (total n = 1303), our results revealed strong evidence for the overall validity of conditioned pupil responses, with a trend for larger effects in aversive (average g = 0.73) vs. appetitive conditioning (g = 0.39). Response differentiation increased over the course of acquisition. Substantial differentiation effects were found in both early and late response windows. Moderator analyses revealed a consistent influence of UCS modality on differential conditioning, while evidence for moderation by contingency instructions and length of acquisition phase was mixed. The results highlight pupil dilation as a sensitive and reliable index of Pavlovian conditioning across valence categories and stimulus modalities. Important implications regarding methodological considerations and research goals are discussed.


Assuntos
Condicionamento Clássico , Pupila , Humanos
11.
Cesk Slov Oftalmol ; 77(4): 192-200, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34507495

RESUMO

PURPOSE: To evaluate the influence of pupil dilation on ocular parameters measured by optical biometry and the influence of pupil dilation on intraocular lens (PC IOL) power calculation by using the third-generation (SRK/T) and the fourth-generation (Haigis) formula. METHODS: 40 eyes of patients indicated for cataract surgery were included in this study. Each patient was examined by optical biometer firstly without artificial mydriasis (AM) and then after AM, which was achieved using local application of short-term acting mydriatics. Biometric data were measured by Lenstar LS 900 optical biometer, we recorded axial length of the eye (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT) and corneal astigmatism and optical power of cornea. These data we measured were used for calculation of the PC IOL optical power using both the SRK/T and the Haigis formula. The target postoperative refraction was set to emmetropia. Statistical analysis was performed for evaluation of influence of AM on each ocular parameter and influence of AM on the recommended PC IOL power calculated by the SRK/T and the Haigis formula. RESULTS: No statistically significant effect of AM on AL, LT and keratometry was demonstrated. On the contrary we demonstrated significant effect on CCT and ACD. No effect of AM on the PC IOL power calculation using the SRK/T formula was proved - the PC IOL optical power before AM and after AM did not differ in any case. When using the Haigis formula for the PC IOL power calculation, the recommended optical power of the PC IOL changed by +0.5 Dpt in 9 eyes, i.e., 22.5 % of the whole group, but statistical analysis did not show this change as statistically significant. CONCLUSION: Pharmacological dilation of the pupil significantly affects some intraocular parameters measured by optical biometer and in the case of using the Haigis formula it can influence recommended power of the PC IOL. Conversely, when using the SRK/T formula, pharmacological dilation of pupil does not affect the recommended PC IOL power.


Assuntos
Catarata , Lentes Intraoculares , Facoemulsificação , Biometria , Humanos , Pupila , Refração Ocular
12.
J Cataract Refract Surg ; 47(9): 1122-1126, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34468448

RESUMO

PURPOSE: To describe the initial experience with the Assia Pupil Expander 200 (APX-200, APX Ophthalmology) in eyes that underwent phacoemulsification or intraocular lens repositioning surgery that required mechanical pupil expansion. SETTING: Department of Ophthalmology, Meir Medical Center, Kfar-Saba, and Ein-Tal Eye Center, Tel Aviv, Israel. DESIGN: Retrospective case series. METHODS: The APX-200 is a single-use device, intended for mechanical expansion of the pupil during intraocular surgery. Two devices are inserted through 2 opposite 19-gauge incisions using designated forceps. The surgical course and early postoperative follow-up was recorded in 50 eyes. RESULTS: The study included 50 consecutive eyes, with mean preoperative pupil diameter was 3.7 mm. The APX effectively dilated the pupils in all cases. No complication related to the use of the APX such as hyphema, iridodialysis, or Descemet membrane detachment were noted in this series. A central and round pupil was restored in all eyes at 1-month postoperatively, with 14 eyes (28%) having mild sphincter tears. Pupilloplasty was not required in any of the cases. CONCLUSIONS: The APX-200 was an effective and safe device for pupil expansion during intraocular surgery.


Assuntos
Extração de Catarata , Facoemulsificação , Humanos , Implante de Lente Intraocular , Pupila , Estudos Retrospectivos
13.
Auton Neurosci ; 235: 102869, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34474355

RESUMO

BACKGROUND: Opioids produce pupillary constriction but their impact on pupillary unrest and the dynamic parameters of the pupillary light reflex have not been characterized. Given the increasing use of portable pupillometers for care of critically ill patients, it is important to distinguish between opioid effects on the pupil versus those that have been reported to arise from traumatic and ischemic brain insults. We undertook this study to determine which pupillary responses are most profoundly and consistently affected by a progressive infusion of remifentanil. METHODS: We studied the effect of remifentanil on the pupil using two portable infrared pupillometers in 18 volunteers. One pupillometer measured pupillary unrest in ambient light (PUAL) and the other pupillometer measured neurological pupillary index (NPi), constriction velocity (CV), pupil diameter (PD), latency, and % reflex (% reflex) following a transient light flash. Remifentanil was administered at predetermined weight-adjusted rates to raise opioid effect site concentration up to a range known to produce respiratory depression and oxyhemoglobin desaturation, based on a previously published pharmacokinetic model. RESULTS: PUAL was ablated by remifentanil, declining 94 ± 6% from baseline at the time of maximum drug effect. Other pupillary measurements decreased 50-65% from baseline. NPi was unchanged. At the time of oxyhemoglobin desaturation, deviations in PD, CV, and % reflex were widely scattered, whereas PUAL consistently approached zero. CONCLUSION: PUAL is a highly specific indicator of central opioid effect. As a non-invasive measure, it may provide useful data to clinicians who prescribe opioids.


Assuntos
Analgésicos Opioides , Reflexo Pupilar , Analgésicos Opioides/farmacologia , Humanos , Pupila
14.
Sci Rep ; 11(1): 17880, 2021 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-34504251

RESUMO

We performed pupillometer testing on 132 patients with Parkinson's disease, stratified into two groups according to the disease stage. Neurological examinations and pupillometry were performed in the ON state. Patients in the Hoehn and Yahr stages 1 and 2 comprised the early group, and patients in stages 3-5 formed the late group. We performed age- and sex-matched (2:1) propensity score matching to compensate for the effect of age on pupil light reflex. Eight pupillometer parameters were measured and compared between the two groups. After the propensity score matching, the early group had 64 patients and the late group had 32 patients. The late group had a longer disease duration and took a higher levodopa equivalent dose than the early group. The constriction velocity (P = 0.006) and maximum constriction velocity (P = 0.005) were significantly faster in the early group than in the late group. Pupil size, minimum diameter, and dilation velocity were similar in both groups. The pupillary contraction velocity decreased with the disease progression, suggesting that the progression of Parkinson's disease could be identified by the pupil constriction velocity.


Assuntos
Progressão da Doença , Exame Neurológico , Doença de Parkinson/patologia , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Exame Neurológico/métodos , Doença de Parkinson/diagnóstico , Doença de Parkinson/tratamento farmacológico , Pupila/efeitos dos fármacos , Reflexo Pupilar/fisiologia , Visão Ocular/efeitos dos fármacos , Visão Ocular/fisiologia
15.
Psychol Sci ; 32(9): 1494-1509, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34473581

RESUMO

People's perceptual reports are biased toward percepts they are motivated to see. The arousal system coordinates the body's response to motivationally significant events and is well positioned to regulate motivational effects on perceptual judgments. However, it remains unclear whether arousal would enhance or reduce motivational biases. Here, we measured pupil dilation as a measure of arousal while participants (N = 38) performed a visual categorization task. We used monetary bonuses to motivate participants to perceive one category over another. Even though the reward-maximizing strategy was to perform the task accurately, participants were more likely to report seeing the desirable category. Furthermore, higher arousal levels were associated with making motivationally biased responses. Analyses using computational models suggested that arousal enhanced motivational effects by biasing evidence accumulation in favor of desirable percepts. These results suggest that heightened arousal biases people toward what they want to see and away from an objective representation of the environment.


Assuntos
Nível de Alerta , Pupila , Viés , Humanos , Motivação , Recompensa
19.
Acta Psychol (Amst) ; 220: 103402, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34506977

RESUMO

The Index of Cognitive Activity (ICA) was introduced as a promising pupillary workload measure for field investigations since, unlike pupil dilation, it is not affected by illumination. Recent studies have investigated the ICA for task-evoked cognitive workload with contradictory findings. However, few studies investigated the influence of illumination on the ICA. Therefore, to examine inconsistencies regarding the reliability for workload measurement and the effects of light, a meta-analysis was conducted based on a structured literature review. The meta-analysis considered k = 14 studies with a total sample size of N = 751 participants. Results showed significant effects for workload (r = 0.61) and light (r = 0.45) on the ICA. Since moderating effects were found for several between-study differences, it seems likely that different cognitive processes and settings affect the indicator and should be considered in empirical investigations. According to the findings, the ICA is a reliable indicator for task-evoked workload. However, light influences were found which indicates that evidence-based conclusions regarding the ICA's practical applicability require further research.


Assuntos
Pupila , Carga de Trabalho , Cognição , Humanos , Reprodutibilidade dos Testes
20.
eNeuro ; 8(5)2021.
Artigo em Inglês | MEDLINE | ID: mdl-34518364

RESUMO

Pupil dynamics alterations have been found in patients affected by a variety of neuropsychiatric conditions, including autism. Studies in mouse models have used pupillometry for phenotypic assessment and as a proxy for arousal. Both in mice and humans, pupillometry is noninvasive and allows for longitudinal experiments supporting temporal specificity; however, its measure requires dedicated setups. Here, we introduce a convolutional neural network that performs online pupillometry in both mice and humans in a web app format. This solution dramatically simplifies the usage of the tool for the nonspecialist and nontechnical operators. Because a modern web browser is the only software requirement, this choice is of great interest given its easy deployment and setup time reduction. The tested model performances indicate that the tool is sensitive enough to detect both locomotor-induced and stimulus-evoked pupillary changes, and its output is comparable to state-of-the-art commercial devices.


Assuntos
Aplicativos Móveis , Animais , Nível de Alerta , Humanos , Camundongos , Pupila
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