Pupil Diameter Research Articles

Comparison of Corneal Higher-order Aberrations Measured by Scheimpflug Camera and Placido Disc-based Topography in Korean Patients

Purpose: We compared corneal higher-order aberration (HOA) measurements between the Pentacam<sup>®</sup> HR (PC), which uses the Scheimpflug principle, and the iTrace<sup>TM</sup> aberrometer (IT), which evaluates Placido disc topography.Methods: We retrospectively analyzed 109 eyes of 87 patients without a history of ocular surface disease during the period from January 2021 to December 2022; both devices were used on the same day. We calculated the root mean square values (μm) of corneal total HOA and of the corneal 3rd- and 4th-order HOA at a pupil diameter of 4 mm. Data were compared by Bland-Altman plots for agreement analysis and Pearson correlation coefficient for correlation analysis.Results: There was no significant difference in the total HOA (<i>p</i> = 0.145), coma (<i>p</i> = 0.309), or secondary astigmatism (<i>p</i> = 0.080) between the PC and IT measurements; all other HOAs significantly differed between devices (<i>p</i> < 0.001). In the correlation analysis, the total HOA (r = 0.605, <i>p</i> < 0.001) and coma (r = 0.634, <i>p</i> < 0.001) were moderately correlated between the two devices; the other HOAs showed low degree of correlations. In the Bland-Altman plot analysis, all HOAs showed low agreement between the two devices.Conclusions: Corneal total HOA and coma measured by the two devices were significantly correlated between the two devices, but other HOAs showed significant differences in measurement and low correlations. Therefore, corneal HOA measurements cannot be interpreted interchangeably between the two devices.

Linking vestibular, tactile, and somatosensory rhythm perception to language development in infancy

First experiences with rhythm occur in the womb, with different rhythmic sources being available to the human fetus. Among sensory modalities, vestibular, tactile, and somatosensory perception plays a crucial role in early processing. However, a limited number of studies so far have specifically focused on VTS rhythms in language development. The present work investigated VTS rhythmic abilities and their role in language acquisition through two experiments with 45 infants (21 females, sex assigned at birth; M age = 661.6 days, SD = 192.6) with middle/high socioeconomic status. Specifically, 37 infants from the original sample completed Experiment 1, assessing VTS rhythmic abilities through a vibrotactile tool for music perception. In Experiment 2, linguistic abilities were evaluated in 40 participants from the same cohort, specifically testing phonological and prosodic processing. Discrimination abilities for rhythmic and linguistic stimuli were inferred from changes in pupil diameter to contingent visual stimuli over time, through a Tobii X-60 eye-tracker. The predictive effect of VTS rhythmic abilities on linguistic processing and the developmental changes occurring across ages were explored in the 32 infants who completed both Experiments 1 and 2 by means of generalized, additive and linear, mixed-effect models. Results are discussed in terms of cross-sensory (i.e., haptic to hearing) and cross-domain (i.e., music to language) effects of rhythm on language acquisition, with implications for typical and atypical development.

The use of quantitative pupillometry in brain death determination: preliminary findings

PurposeQuantitative pupillometry (QP) has been increasingly applied in neurocritical care as an easy-to-use and reliable technique for evaluating the pupillary light reflex (PLR). Here, we report our preliminary findings on using QP for clinical brain death (BD) determination.MaterialsThis retrospective study included 17 patients ≥ 18 years (mean age, 57.3 years; standard deviation, 15.8 years) with confirmed BD, as defined by German Guidelines for the determination of BD. The PLR was tested using the NPi®-200 Pupillometer (Neuroptics, Laguna Hill, USA), a handheld infrared device automatically tracking and analyzing pupil dynamics over 3 s. In addition, pupil diameter and neurological pupil index (NPi) were also evaluated.ResultsIntracerebral bleeding, subarachnoid hemorrhage, and hypoxic encephalopathy were the most prevalent causes of BD. In all patients, the NPi was 0 for both eyes, indicating the cessation of mid-brain function. The mean diameter was 4.9 mm (± 1.3) for the right pupil and 5.2 mm (±1.2) for the left pupil.ConclusionsQP is a valuable tool for the BD certification process to assess the loss of PLR due to the cessation of brain stem function. Furthermore, implementing QP before the withdrawal of life-sustaining therapy in brain-injured patients may reduce the rate of missed organ donation opportunities. Further studies are warranted to substantiate the feasibility and potential of this technique in treating patients and identify suitable candidates for this technique during the BD certification process.

Factors influencing dominant eye selection in refractive surgery patients: A correlation analysis

ObjectiveThis study aims to reveal the factors influencing the selection of the dominant eye in refractive surgery patients, and enhance the accuracy of clinical evaluation and surgical treatment. MethodsA retrospective study method was employed. The ocular biometric parameters were analyzed in 4,114 patients who underwent refractive surgery at the affiliated hospital of Southwest Medical University from 2019 to 2023. ResultsThe study found that 79.07% of the patients had the right eye as the dominant eye, while 20.93% had the left eye. Although there was no significant difference between the dominant and non-dominant eyes in terms of uncorrected visual acuity and Kappa angle, the dominant eye performed better in aspects such as spherical lens, eye axis, and corneal flat curvature. Furthermore, univariate and multivariate logistic regression results showed that best-corrected visual acuity, pupil diameter, horizontal displacement x-value of the Kappa angle, and astigmatism vector J45 were significant influencing factors for the selection of the dominant eye. ConclusionThere are numerous factors affecting the dominant eye, and the most important core factor is J45. This study comprehensively evaluated the possible factors affecting the dominant eye in patients undergoing refractive surgery, which provides a foundation for the designation of refractive surgical modalities and assurance of surgical outcomes, and opens up new perspectives on understanding the mechanisms of the formation and development of the dominant eye.

What is the visual behaviour and attentional effort of football players in different positions during a real 11v11 game? A pilot study.

Visual perception has been defined as the first step to a football player's decision-making process and it plays an important role in performance in sport. The skill of focussing to prioritize relevant cues has been also considered crucial in sport. This pilot study aims to explore the visual behaviour and attentional effort of three football players (mean age 19 ± 0 years old) in specific-role positions; Right-winger (RW), Centre-Midfielder (CM) and Left-Back (LB), in the five seconds before receiving the ball from their teammate. Twenty-two male football players performed an 11v11 game, where 24 game sequences (trials) from which 166 fixations were recorded and analysed via the Tobii Pro eye-movement registration glasses and software. The gaze behaviour dependent variables were the mean of fixation duration (FD), time to first fixation (TTF), both measured in milliseconds (ms), and the number of fixations (NF) on eight areas of interest (AOIs). AOIs include teammate with and without the ball, opponent without the ball, space around teammate with and without the ball, space around opponent without the ball, ball and undefined. The mean pupil diameter (PD) correlates to the attentional effort and was measured in millimetres (mm). Descriptive statistics showed nonregular search rate data between the participants in FD, TTF, NF on the AOIs. Mean FD on the ball: (CM, 270 ms), (RW, 570 ms), (CM, 380 ms). They also presented differences in the mean PD during play; (CM: 2.90 mm ± 0.26), (RW: 2.74 mm ± 0.30), (LB 2.77mm ± 0.27). Albeit the sample size was small, the findings demonstrated a promising way to measure the on-field perceptual-cognitive abilities of football players according to their specific positions, since different playing roles revealed to present distinctive visual and attentional patterns. This could potentially assist in tailoring players 'visual and focus training.

Hypoxic acclimatization training improves the resistance to motion sickness.

Vestibular provocation is one of the main causes of flight illusions, and its occurrence is closely related to the susceptibility of motion sickness (MS). However, existing training programs have limited effect in improving the resistance to motion sickness. In this study, we investigated the effects of hypoxia acclimatization training (HAT) on the resistance to motion sickness. Healthy military college students were identified as subjects according to the criteria. MS model was induced by a rotary chair. Experimental groups included control, HAT, 3D roller training (3DRT), and combined training. The Graybiel scores were decreased in the HAT group and the 3DRT group and further decreased in the combined training group in MS induced by the rotary chair. Participants had a significant increase in blood pressure after the rotary chair test and a significant increase in the heart rate during the rotary chair test, but these changes disappeared in all three training groups. Additionally, LFn was increased, HFn was decreased, and LF/HF was increased accordingly during the rotary chair test in the control group, but the changes of these three parameters were completely opposite in the three training groups during the rotary chair test. Compared with the control group, the decreasing changes in pupillary contraction velocity (PCV) and pupillary minimum diameter (PMD) of the three training groups were smaller. In particular, the binocular PCV changes were further attenuated in the combined training group. Our research provides a possible candidate solution for training military pilots in the resistance to motion sickness.

Optical Behavior of an Enhanced Monofocal Intraocular Lens Compared with a Standard One

The aim of this work was to compare an enhanced monofocal (RayOne EMV RAO200E, Rayner) and standard monofocal (RayOne RAO600C Aspheric, Rayner) intraocular lenses (IOLs) for three nominal powers (+10.00 D, +20.00 D and +30.00 D) as a function of the optical aperture diameter (pupil diameter) using a commercial Schlieren phase-shifting deflectometer NIMO TR1504 (Lambda-X, Belgium). From the wavefront maps measured by this instrument, the radial power profiles, the spherical aberration coefficients of the Zernike polynomial expansion (as a function of the optical aperture radius), and the root-mean-square (RMS) of the high-order aberrations (HOAs) were obtained and analyzed by comparing the two models. The results showed that the effective added power that could be obtained with the enhanced model depended directly on the pupil size and the power of the IOL implanted. The higher additions were achieved with the higher nominal IOL powers. The relationship between the pupil diameter, the corneal aberration of the patients and the power profile of these IOLs could have a crucial implication on the far distance and the final effective addition. However, it is important to note that these findings should be clinically validated through the implantation of these models in patients’ lenses.

Comparisons of biometric parameters measurements by OPD-SCAN Ⅲ and Pentacam in cataract

BackgroundComparison of OPD-Scan III and Pentacam measurements of relevant parameters guiding the selection of multifocal intraocular lenses in cataract patients. MethodsA retrospective study included 120 patients (120 eyes) with cataract. Their chord kappa, chord alpha, corneal spherical aberration, and pupil size were measured by OPD-Scan Ⅲ and Pentacam. Pairwise t-tests, Pearson tests, and Bland-Altman analyses were used, respectively, to assess the difference, correlation, and agreement between the devices. ResultsThere was no significant difference in photopic chord kappa and corneal spherical aberration between the two instruments (P = 0.054, P = 0.065). Chord alpha and pupil size varied significantly between the two instruments (P < 0.001). OPD-Scan III results revealed a significant association between photopic chord kappa and mesopic chord kappa (r = 0.823, P < 0.001). There was a significant positive correlation between photopic and mesopic chord kappa measured by OPD-Scan Ⅲ and chord kappa measured by Pentacam (r = 0.840, r = 0.757, P < 0.001). The chord alpha evaluated by the two tools had a moderate correlation (r = 0.442, P < 0.001) between them. Bland-Altman analysis showed that there was excellent agreement between the two instruments in measuring chord kappa and corneal spherical aberration, while the chord alpha and pupil size were not consistent. ConclusionsThe chord kappa and corneal spherical aberration measured by OPD-Scan III and Pentacam were consistent in the preoperative decision making of multifocal intraocular lens implantation in cataract patients, both of which have clinical guiding significance. In addition, OPD-Scan III provides more comprehensive day and night chord kappa and pupil diameters, which improves clinical advice for patients with complicated ocular diseases and high demands for nocturnal vision.

Pupillometry as a marker of arousal and in relation to cognition and cortical dynamics in Alzheimer’s disease

AbstractBackgroundPupil dilation is an established measure of noradrenergic activity. Cortical EEG alpha power, a measure of attentional engagement, can be recorded simultaneously with pupillometry. Dysfunction in the noradrenergic system in Alzheimer’s disease (AD), contributes to the attentional deficits seen in patients. We investigated whether pupillometry recorded at rest can be used to show reduced noradrenergic activity in AD and how this relates to cortical dynamics.MethodWe recorded simultaneous EEG and pupillometry during 5min of eyes‐open resting‐state in 28 AD patients and 22 age‐matched controls (HC). Pupil dilations – peaks of both pupil diameter and velocity – were identified (Fig. 1A/B). Average pupil diameter and velocity were calculated across all dilations, and compared between groups (Fig. 1 C/D). We plotted EEG power spectra for the 2s pupil dilation‐centred epochs (Fig. 2A). The frequency at which there was the greatest power within the alpha band – the peak alpha frequency (PAF) – was calculated for each individual and compared across groups (Fig. 2B). We then measured the alpha power during the pupil‐dilation epochs and looked at the relationship with the pupils (Fig. 3).ResultIn HCs, the mean pupil dilations – peaks in diameter and peaks in velocity – were greater than in AD; t = ‐2.62 p = 0.01 and t = ‐2.26 p = 0.03, respectively (Fig. 1C/D). Power spectra for the 2s pupil dilation‐centred epochs showed patients’ PAF was significantly lower than HC’s; t = 2.92 p&lt;0.01 (Fig. 2). There was a corresponding peak in alpha power associated with the pupil dilations, in both groups. Regarding peaks in pupil diameter, the alpha power peaked approximately 0.5sec earlier (Fig. 3A). Regarding peaks in pupil velocity, the alpha power peaked simultaneously with the pupils (Fig. 3B).ConclusionThere is a reduction in size and velocity of spontaneous pupil dilations in AD. EEG alpha is shifted to lower frequencies in AD. There is a preserved relationship between pupil dilations and alpha peaks in AD. Pupillometry offers a means of measuring noradrenergic dysfunction in AD that relates to altered cortical dynamics.

Clinical Results and Factors Affecting Visual Function in Eyes Implanted with an Enhanced Monofocal Intraocular Lens.

To compare the clinical results achieved with the enhanced monofocal intraocular lenses (IOLs) with those of the monofocal IOL and investigate factors affecting the distance, intermediate, and near vision. Patients were included who underwent bilateral consecutive cataract surgeries using the same IOLs with follow-up to 1 month postoperatively. Refractions, monocular UDVA and CDVA, and binocular distance-corrected functional visual acuity at 5 meters (BDCFVA), at 66 centimeters (BDCIFVA) and at 40 centimeters (DCNVA) were assessed. Multiple regression analysis was used to assess the factors affecting binocular BDCFVA, BDCIFVA, and BDCNFVA. Subjective symptoms were assessed using the Near Activity Visual Questionnaire (NAVQ) and visual analogue scale (VAS). Sixty patients (120 eyes) implanted with the Tecnis Eyhance IOL (30 patients, 60 eyes) or the Tecnis monofocal IOL (30 patients, 60 eyes) were included. The Tecnis Eyhance IOL provided significantly better binocular BDCIFVA than the Tecnis monofocal IOL in patients under 70 years of age. Multiple regression analysis showed that age was the only factor affecting distance and intermediate visual function in eyes with the Tecnis Eyhance IOL; gender, pupillary diameter, axial length, and average keratometry were not significant. There were no significant differences in subjective symptoms. The comprehensive cohort analysis did not confirm the advantage on the intermediate vision of the Tecnis Eyhance IOL. Younger age may be an important factor to benefit from the unique optical characteristics of this IOL.

Protocol for a parallel assignment prospective, randomised, double-blinded, placebo-controlled trial to evaluate the efficacy of 0.01% atropine for near work-induced transient myopia and myopic progression in China

IntroductionAssessment of near work-induced transient myopia (NITM) is important for permanent myopia development and progression. Atropine eye drop has been reported to be beneficial in reducing initial NITM and slowing...

The Outbreak of Acute Primary Angle-Closure Cases During the COVID-19 Omicron Variant Pandemic at a Tertiary Eye Center in Shanghai.

This study aimed to investigate the outbreak of acute primary angle-closure (APAC) during the COVID-19 Omicron variant pandemic in Shanghai. This single-center retrospective observational study included all newly diagnosed patients with APAC in Eye, Ear, Nose, and Throat Hospital of Fudan University from December 15, 2022, to January 14, 2023 (pandemic group) during the COVID-19 pandemic of Omicron Variant, and from November 15, 2021, to February 14, 2022 (control group) when the infection rate of COVID-19 is very low in Shanghai. Demographic features, intraocular pressure, axial length, anterior chamber depth, lens thickness and pupil diameter were compared between the two groups. A total of 223 patients (261 eyes) were included in the pandemic group and 75 patients (82 eyes) in the control group. The number of APAC patients and eyes in the pandemic group is 8.92-fold and 9.55-fold of the monthly average number in the control group. The onset dates of acute angle-closure were mainly between December 17 and December 31, 2022. In the pandemic group, 72.65% of patients with APAC had a recent COVID-19 infection. Among the COVID-19-positive patients, 72% suffered APAC attacks within 24h of the occurrence of COVID-19 symptoms and 92% within 3 days. The pandemic group showed a longer time from symptoms to treatment and larger pupil diameter than the control group (7.92 ± 6.14 vs 3.63 ± 2.93 days, p = 0.006; 4.53 ± 1.17 vs 3.78 ± 1.24 mm, p = 0.003, respectively). An outbreak of APAC attack was observed in our eye center during the COVID-19 Omicron variant pandemic in Shanghai. There may be a correlation between the onset of APAC and new COVID-19 Omicron variant infection, but the exact reason needs to be investigated further.

Using artificial intelligence (AI) to predict the conversion of cognitively unimpaired individuals to mild cognitive impairment

AbstractBackgroundMild cognitive impairment (MCI) is the objective decline in neurocognitive functioning, but without significant impairment of the individual’s ability to perform the usual instrumental activities of daily living (1). Diagnosing MCI can be done using a combination of different methods such as cognitive testing, structural neuroimaging, nuclear imaging, and cerebrospinal fluids, and plasma biomarkers. Some of these methods are invasive and expensive. Machine learning (ML) algorithms can be trained to predict the onset of MCI, using data from non‐invasive methods.MethodFour databases (WoS, MEDLINE, EMBASE, and CINAHL) were searched using search string of relevant terms (cognitive decline, artificial intelligence, prediction, and cognitively unimpaired). Articles that reportedtrained ML algorithms using non‐invasive predictors of MCI in cognitively healthy adults (≥ 18 years old) were included. The review was registered with PROSPERO (CRD42022379027) and PRISMA guidelines were followed. The Newcastle‐Ottawa Quality Assessment scale was used to assess the quality of studies.ResultOf the 1,098 articles identified and screened, 22 studies were included. 373 non‐invasive predictors of MCI were identified. The most prevalent predictors included: demographic information (age, sex, years in education), voice and speech parameters (sentence repeating, semantic fluency), gait parameters (velocity, cadence, step time), performance on cognitive tests (MMSE, K‐MoCA, CDR, AD8), eye‐movements (pupil diameter, saccade orientation) and Instrumental activity of daily livings (medication, finance management). The maximum and minimum number of predictors used to develop a ML algorithm was 121 and 2, respectively. The ML algorithms developed in the included studies had (average sensitivity and specificity of 77.90%±22 and 80.84%±18, respectively) exceeded the performance of algorithms that used invasive and expensive predictors such as nuclear imaging and neuroimaging which achieved accuracy scores (60%‐77%) (2).ConclusionNon‐invasive predictors can be used to train ML algorithms to predict the onset of MCI in cognitively healthy individuals with good accuracy scores exceeding 70%. These algorithms may can aid clinician decision making, thus setting early treatment plans, and allowing individuals to be involved in care planning before progression of MCI to dementia AD.

What is the visual behaviour and attentional effort of football players in different positions during a real 11v11 game? A pilot study

Background Visual perception has been defined as the first step to a football player’s decision-making process and it plays an important role in performance in sport. The skill of focussing to prioritize relevant cues has been also considered crucial in sport. This pilot study aims to explore the visual behaviour and attentional effort of three football players (mean age 19 ± 0 years old) in specific-role positions; Right-winger (RW), Centre-Midfielder (CM) and Left-Back (LB), in the five seconds before receiving the ball from their teammate. Methods Twenty-two male football players performed an 11v11 game, where 24 game sequences (trials) from which 166 fixations were recorded and analysed via the Tobii Pro eye-movement registration glasses and software. The gaze behaviour dependent variables were the mean of fixation duration (FD), time to first fixation (TTF), both measured in milliseconds (ms), and the number of fixations (NF) on eight areas of interest (AOIs). AOIs include teammate with and without the ball, opponent without the ball, space around teammate with and without the ball, space around opponent without the ball, ball and undefined. The mean pupil diameter (PD) correlates to the attentional effort and was measured in millimetres (mm). Results Descriptive statistics showed nonregular search rate data between the participants in FD, TTF, NF on the AOIs. Mean FD on the ball: (CM, 270 ms), (RW, 570 ms), (CM, 380 ms). They also presented differences in the mean PD during play; (CM: 2.90 mm ± 0.26), (RW: 2.74 mm ± 0.30), (LB 2.77mm ± 0.27). Conclusions Albeit the sample size was small, the findings demonstrated a promising way to measure the on-field perceptual-cognitive abilities of football players according to their specific positions, since different playing roles revealed to present distinctive visual and attentional patterns.

Test‐retest validity of light reflex pupillometry in a memory clinic cohort

AbstractBackgroundThe pupillary light reflex and the contributing cerebral functions can be objectively assessed using a pupillometer. Light reflex pupillometry (LRP) has been found to be altered in Alzheimer’s disease (AD) and has potential as a diagnostic aid in this disease as a novel biomarker. Little is known about the variability of LRP in patients seen in memory clinics (including patients with AD). We aimed to quantify the test‐retest validity of LRP in these patients to elucidate possible pitfalls in using pupillometry and to ascertain the feasibility of implementing this clinical tool in a memory clinic setting.MethodIn total, 50 patients under diagnostic evaluation in a tertiary memory clinic will be included in the present study. Patients suspected of a neurodegenerative disease are included on the day of a scheduled lumbar puncture (LP). We measure the LRP at baseline (day of LP), 3‐14 days after LP, and 21‐35 days post‐LP using a research grade pupillometer (PLR‐3000, NeurOptics®). Spaghettiograms of measurements will be presented and the intraclass correlation coefficient from a two‐way mixed effects model will be calculated for the eight pupillometric variables provided by the PLR‐3000: Baseline pupil diameter, peak constriction diameter, change in pupillary size, average and maximum constriction velocity, average dilation velocity and T75 (time to reach 75% of baseline pupil diameter after peak constriction). We will study possible influencing factors that could affect the test‐retest variability by studying subgroups of patients based on diagnosis, disease severity, cerebrospinal fluid Aβ‐42, concurrent eye disease and medication.ResultAs of January 2023, 24 patients (9 female) have completed follow‐up. The mean age of patients is 72 years (range 63‐79). Half of the patients were diagnosed with Alzheimer’s disease (MCI or mild dementia). Our preliminary results show moderate‐good test‐retest reliability of most pupillometric variables.ConclusionLight reflex pupillometry may be a promising new bedside biomarker for AD. The present study generally demonstrated a moderate‐good test‐retest reliability of LRP in a memory clinic population. The study contributes to the foundation for an exploration of the tool for diagnostic purposes in various diseases, including Alzheimer’s disease.

Relationship of Low-luminance Visual Acuity with Ocular Aberrations in Older Participants.

This study highlights the importance of twilight adaptation for reliable assessment of low-luminance visual acuity and understanding the relationship between low-luminance visual acuity and ocular aberrations. The human eye experiences reduced visual acuity as luminance decreases owing to reduced retinal and optical resolutions; however, the details are unclear. This study aimed to quantify the effects of refraction, pupil diameter, and ocular aberrations on visual acuity during the transition from high- to low-light environments, thereby contributing to the standardization of low-luminance visual acuity measurements. In total, 27 older participants with a mean age of 70.0 ± 4.1 years were included in this study. Visual acuity was measured according to the Early Treatment Diabetic Retinopathy Study (ETDRS) protocol with three luminance conditions: high luminance (300 cd/m 2 ), low luminance (10 cd/m 2 ), and low luminance with short-term (15-minute) twilight adaptation (10 cd/m 2 ). The mean logarithm of minimum angle of resolution values of visual acuity were -0.09 ± 0.09, 0.10 ± 0.13, and 0.03 ± 0.09 at 300, 10, and 10 cd/m 2 with twilight adaptation, respectively. Multiple regression analysis determined that spherical aberration ( P < .005) and tetrafoil ( P < .005) were significant factors associated with low-luminance visual acuity after twilight adaptation, with an adjusted R2 value of 0.35 for this model ( P < .005). Although the influence of ocular aberrations on low-luminance visual acuity may be relatively modest compared with neural effects, it remains a crucial factor that should not be overlooked. The absence of twilight (or dark) adaptation can cause ocular aberrations and neural effects, potentially leading to inaccuracies in the measurement of low-luminance visual acuity.

Study in Patients With Unilateral Horner Syndrome Supports the Role of Müller's Muscle in the Eyelid-Dark Reflex.

A previous study demonstrated upper eyelid retraction synchronized with pupil dilation following a transition from photopic to scotopic conditions. The current study aimed to evaluate the role of Müller's muscle as the efferent arm of this suggested reflex arc. A video scan of both eyes of patients with unilateral Horner syndrome was performed using optical coherence tomography infra-red mode to document the transition between photopic and scotopic conditions. The affected side with sympathetic denervation was the study group, whereas the contralateral unaffected side of the same patients served as the control group. The pupil diameter, upper eyelid margin-to-reflex distance 1, lower eyelid margin-to-reflex distance 2, and vertical palpebral fissure height were measured. The control group was compared to the healthy subjects of a previous study to verify any compensatory changes to the side contralateral to denervation. Ten patients with unilateral Horner Syndrome were included in the study. Transitioning from photopic to scotopic conditions, the mean change in margin-to-reflex distance 1 in the study and control groups was 315 ± 276 µm (P < 0.05) and 723 ± 432 µm (P = 0.005), respectively. Margin-to-reflex distance 1 and palpebral fissure height were significantly higher in the control group both in photopic (P = 0.005 and P = 0.017, respectively) and scotopic conditions (P = 0.005 and P = 0.007, respectively). The change in margin-to-reflex distance 1 and palpebral fissure height following the transition from light to dark was significantly greater in the control group (P = 0.022). Reflexive eyelid retraction following a transition from photopic to scotopic conditions was significantly diminished in eyelids with sympathetic denervation compared with the unaffected contralateral side of the same patients. This study provides further evidence that the sympathetically innervated Müller's muscle serves as the efferent arm of this reflex.

Visual attention predictive model of built colonial heritage based on visual behaviour and subjective evaluation

Although physiological measurements, subjective evaluation and other methods have been applied to visual attention research, architects still lack a systematic quantitative classification method when assessing the visual attention to built colonial heritage. This study aimed to investigate the relationship between people’s visual behaviour and subjective evaluation when observing built colonial heritage and to construct a prediction model based on eye-movement metrics and subjective evaluation indicators to distinguish the visual attention to built colonial heritage. This study recorded data from 54 participants while observing five scenes of built colonial heritage, and the results showed that participants had different visual behaviours and subjective evaluations when viewing built colonial heritage in different scenes. And visual attention to built colonial heritage was negatively correlated with the average saccades peak velocity and average saccades amplitude and positively correlated with the average pupil diameter; visual attention was correlated with 12 subjective evaluation indicators. The eye-movement metrics and subjective evaluation indicators with correlation to visual attention were used as input variables to construct a prediction model of visual attention to built colonial heritage based on the BP neural network. Different built colonial heritage’s low, middle and high visual attention were identified with high accuracy (74.46%). This quantitative method can help architects to measure the visual attention to built colonial heritage to develop conservation and renewal strategies.

Evaluation of physiological responses to mental workload in n-back and arithmetic tasks

Working memory tasks, such as n-back and arithmetic tasks, are frequently used in studying mental workload. The present study investigated and compared the sensitivity of several physiological measures at three levels of difficulty of n-back and arithmetic tasks. The results showed significant differences in fixation duration and pupil diameter among three task difficulty levels for both n-back and arithmetic tasks. Pupil diameters increase with increasing mental workload, whereas fixation duration decreases. Blink duration and heart rate (HR) were significantly increased as task difficulty increased in the n-back task, while root mean square of successive differences (RMSSD) and standard deviation of R-R intervals (SDNN) were significantly decreased in the arithmetic task. On the other hand, blink rate and Galvanic Skin Response (GSR) were not sensitive enough to assess the differences in task difficulty for both tasks. All significant physiological measures yielded significant differences between low and high task difficulty except for SDNN. Practitioner summary: This study aimed to assess the sensitivity levels of several physiological measures of mental workload in n-back and arithmetic tasks. It showed that pupil diameter was the most sensitive in both tasks. This study also found that most physiological indices are sensitive to an extreme change in task difficulty levels.

The characteristics of driver lane-changing behaviour in congested road environments

Abstract Lane-changing behaviour is one of the complex driving behaviours. The lane-changing behaviour of drivers may exacerbate congestion, however driver behavioural characteristics are difficult to accurately acquire and quantify, and thus tend to be simplified or ignored in existing lane-changing models. In this paper, the Bik-means clustering algorithm is used to analyse the urban road congestion state discrimination method. Then, simulated driving tests were conducted for different traffic congestion conditions. Through the force feedback system and infrared camera, the data of driver lane-changing behaviours at different traffic congestion levels are obtained separately, and the definitions of the start and end points of a vehicle changing lanes are determined. Furthermore, statistical analysis and discussion of key feature parameters including driver lane-changing behaviour data and visual data under different levels of traffic congestion were conducted. It is found that the average lane-change intention times in each congestion state are 2 s, 4 s, 6 s and 7 s, while the turn-signal duration and the number of rear-view mirror observations have similar patterns of change to the data on lane-changing intention duration. Moreover, drivers’ pupil diameters become smaller during the lane-changing intention phase, and then relatively enlarge during lane-changing; the range of pupil variation is roughly 3.5 mm to 4 mm. The frequency of observing the vehicle in front of the target lane increased as the level of congestion increased, and the frequency of observation in the driver's mirrors while changing lanes approximately doubled compared to driving straight ahead, and this ratio increased as the level of congestion increased.