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AbstractPurposeMethodsResultsConclusionTo assess the relationship between angle kappa (apparent chord mu) and ocular parameters in cataract patients.In this cross-sectional study, the data on apparent chord mu, age, axial length, anterior chamber depth, anterior and posterior mean keratometry, mean total keratometry, white-to-white, central corneal thickness and lens thickness were collected for consecutive cataract patients. Correlation (Pearson) between chord mu and the other ocular parameters was calculated. A stepwise backward multiple regression analysis was performed to identify the combination of ocular parameters strongly correlating to chord mu.Two thousand four hundred and sixty-four eyes (1232 patients) were included in this study. The mean age was 72.7 ± 12.7 years (18–97 years). Univariate analysis showed a significant positive correlation of chord mu to age (R = 0.06, p = .01), lens thickness (R = 0.12, p < .01), mean keratometry (R = 0.08, p < .01), and mean total keratometry (R = 0.08, p < .01). Whereas there was a significant negative correlation with white-to-white (R = −0.04, p = .03), axial length (R = −0.19, p < .01), and anterior chamber depth (R = −0.2, p < .01). Male gender (R = −0.04, p = .05) and central corneal thickness (R = 0.04, p = .06) were not significantly correlated. Multivariate stepwise backward regression analysis showed a combination of four factors (female sex, reduced axial length and anterior chamber depth and steep mean keratometry) significantly related to chord mu (angle kappa).Female gender, reduced axial length and anterior chamber depth, and higher mean keratometry correlate to apparent chord mu (angle kappa) in cataract patients. These findings can help identify vulnerable patients who can have appropriate counseling on the prognosis of postoperative optical and visual outcomes. [ABSTRACT FROM AUTHOR]

Photic phenomena are more pronounced in presbyopia-corrected than in monofocal intraocular lens (IOL), causing dissatisfaction after cataract surgery. Photic Phenomena Test (PPT) quantifies photic phenomena in eyes with two types of presbyopia-corrected IOL. We examined the relationship between preoperative eye shape and pupil diameter. We included patients with PanOptix IOLs (PanOptix group, n = 38; 65.7 ± 9.2 years old) and Synergy IOLs (Synergy group, n = 39; 61.9 ± 9.6 years old), who underwent the PPT between 1 and 3 months after cataract surgery, from January 2021 to April 2023. The relationships between age, sex, pupil diameter, and higher-order corneal aberrations were examined and mean values for PPT measurements were compared between the groups. There was no difference in glare between the two groups. The halo was larger and thicker, and the starburst was larger and stronger in the Synergy group (P < 0.01). Postoperative halo brightness was positively correlated with the corneal coma aberration in the PanOptix group (P < 0.05). The Synergy group showed a positive correlation between the size and brightness of the postoperative halo and starburst and pupil diameter (P < 0.01). PPT, thus, revealed risk factors in eyes with two types of presbyopia-corrected IOL, which can be examined before cataract surgery to provide critical information for IOL selection. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusions To investigate the effects of a 0.02 mg/kg dose of intravenous buprenorphine on various ocular parameters in healthy dogs. Animals: 25 healthy, client‐owned dogs.Objective parameters (intraocular pressure [IOP], pupil size [PS]) and subjective parameters (menace response, dazzle reflex, corneal reflex, globe position, and third eyelid position) were measured prior to and following administration of buprenorphine. Baseline data was first established by measuring ocular parameters 20 min prior to (T−20) and immediately before (T0) intravenous administration of a 0.02 mg/kg dose of buprenorphine. Data was then collected again at 10, 20, 30, and 45 min post‐administration (T10, T20, T30, and T45 respectively).There was no significant change in any parameter measured in the baseline data, between T−20 and T0. No significant change was observed in the subjective parameters at any of the time points measured in the post‐drug administration period. There was a significant decrease in PS between T0 and T10 (p < .05) which continued to decrease significantly across timepoints. Both eyes showed a significant, but transient increase in IOP. This increase was followed by a significant decrease in IOP OD and an approaching significant decrease in IOP OS. All variations in IOP remained within the normal canine range.A 0.02 mg/kg dose of intravenous buprenorphine impacts both PS and IOP and, therefore, should be used with caution in select diseases where effects on pupil size and intraocular pressure may cause additional harm. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate clinical outcomes obtained after cataract surgery involving the implantation of a trifocal hydrophobic intraocular lens (IOL) and to determine if pupil size and the corneal aberrometric profile correlate to visual acuity at different distances. Methods: 49 patients (98 eyes) underwent bilateral cataract surgery with the placement of FineVision HP IOLs for presbyopia and were assessed at 1- and 3- to 6-months post-surgery. Postoperatively, refraction, monocular and binocular uncorrected and corrected distance visual acuity (UDVA and CDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA) and the binocular defocus curve were measured. Pupil size and corneal aberrations (higher-order and low-order aberrations; HOA and LOA) were also measured using a Scheimpflug 3D camera. Results: Sphere, cylinder and spherical equivalent decreased significantly after surgery (p< 0.05) and CDVA had improved significantly 1-month post-surgery (p=0.007). The sphere, cylinder, spherical equivalent and CDVA values remained stable at the 3- to 6-month follow-up (p> 0.05). Binocular UDVA was 0 logMAR or better for 79.2% of patients and binocular UNVA was 0.1 logMAR or better for 91.7%. The binocular defocus curve showed average maximum visual acuity values at – 0.07± 0.06 logMAR, 0.01± 0.06 logMAR, and 0.01± 0.06 logMAR, for far, intermediate and near distances, respectively. Neither the UDVA nor UNVA values correlated with patient pupil diameter (UDVA: r=0.035, p=0.744; UNVA: r=− 0.073, p=0.492). Neither the UDVA nor UNVA values correlated with patient HOA or LOA (UDVA versus HOA: r=0.016, p=0.872; UDVA versus LOA: r=0.032, p=0.759; UNVA versus HOA: r=0.056, p=0.582; UNVA versus LOA: r=0.059, p=0.568). Conclusion: This study shows that the FineVision HP IOL provides excellent refractive and visual outcomes at different distances. Pupil size does not correlate with UDVA and UNVA and quality of vision does not seem to correlate with the corneal aberrometric profile. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate whether depth of focus after the implantation of extended depth of focus (EDoF) intraocular lenses (IOLs) correlates with pupillary size. Methods: This retrospective case series study evaluated eyes undergoing cataract surgery with implantation of EDoF IOLs. At least one month postoperatively, the depth of focus (DoF) was measured to determine the correlation with pupillary size, age, anterior chamber depth (ACD), axial length (AXL), and corneal spherical aberrations (SA). Results: The study evaluated 64 eyes of 49 patients. The mean depth of focus was 2.67 diopters (D). The mean preoperative photopic pupil size was 3.36 mm. A significant negative association was found between preoperative photopic pupil size and depth of focus (r = 0.30, Pearson's correlation coefficient) and between preoperative mesopic pupil size and depth of focus (r = 0.274, Pearson's correlation coefficient). Key messages: What is known: • Optical and visual performance of a multifocal IOL likely depends on pupil size. What is new: • Smaller pupil size (including preoperative photopic, mesopic pupil size) had strong association with good post-operative depth of focus, with Extended Depth of Focus Intraocular Lenses. • No significant correlation was observed between age, anterior chamber depth, axial length, corneal spherical aberra?tions, and depth of focus in the Extended Depth of Focus Intraocular Lenses. [ABSTRACT FROM AUTHOR]

Despite the tight link between the visibility of the iris and pupil, the perceived effects of these two have been studied largely in isolation. We demonstrate, across two experimental studies, that the effects of perceived pupil size are dependent on the visibility of the iris. In a first study, our participants donated more and had more positive impressions of portraits of non-human primates when these were manipulated to appear having larger pupils. Post-hoc inspection of our data suggested that the difference was greater for species with more conspicuous irises. In a second study, we concomitantly manipulated iris brightness and pupil size. Brighter irises and larger pupils elicited greater donations. Participants rated photographs with brighter irises as cuter, more attractive and friendlier, but only when they had dilated pupils. Our results have methodological implications for studies manipulating eye appearance, and help interpret results from previous studies. [ABSTRACT FROM AUTHOR]

Clinical relevance: Pupil size evaluation using clinical examination may be important for detecting and monitoring individuals at risk of neurotoxic effects from chemical exposure, as it may enable early intervention and the implementation of preventive measures. Background: This work aimed to investigate the association between pesticide exposure and pupil size. Pupil size is regulated by muscarinic and nicotinic receptors, and it is well-established that common pesticide chemicals disrupt this regulation. Methods: Twenty agricultural workers exposed to pesticides, and twenty participants not exposed, underwent visual screening, and pupil size evaluation under mesopic and photopic conditions. Additionally, signs of neurotoxicity and pesticide exposure in both groups were evaluated using the modified version of the neurotoxic symptoms questionnaire (Q16) and measuring cholinesterase (AChE) levels in blood, respectively. Results: Agricultural workers exposed to pesticides had a score indicating medium–high level of neurotoxicity (49.85 (SD ± 8.94)) which was significantly higher (t (36) = 7.659, p ≤ 0.0001) than non-exposed participants who had low levels of neurotoxicity (27.25 SD ± 8.86). There was a significant difference in pupil size (mm) under mesopic (t (19) 4.42 p = 0.003) and scotopic (t (19) 4.63, p = 0.0002) conditions between the two groups. Additionally, there was a significant difference in AChE blood levels (t (19) 2.94 p = 0.008) between exposed and non-exposed participants, indicating that exposed workers had low levels of this enzyme (average exposed group 3381 U/L (SD ± 1306)) compared to the non-exposed group (average non-exposed group 4765 U/L (SD ± 1300)). A significant negative correlation between AChE levels, years of exposure, and pupil size was found. The latter finding importantly showed that smaller pupils are associated with the accumulation of acetylcholine or a decrease in the activity of the enzyme AChE. Conclusion: Pupil size of agricultural workers exposed to pesticides can be abnormal and is associated with neurotoxicity as indicated by symptomatology and cholinesterase levels. Evaluation of pupil size may be useful for clinically detecting neurotoxicity. [ABSTRACT FROM AUTHOR]

Abstract Photic phenomena are more pronounced in presbyopia-corrected than in monofocal intraocular lens (IOL), causing dissatisfaction after cataract surgery. Photic Phenomena Test (PPT) quantifies photic phenomena in eyes with two types of presbyopia-corrected IOL. We examined the relationship between preoperative eye shape and pupil diameter. We included patients with PanOptix IOLs (PanOptix group, n = 38; 65.7 ± 9.2 years old) and Synergy IOLs (Synergy group, n = 39; 61.9 ± 9.6 years old), who underwent the PPT between 1 and 3 months after cataract surgery, from January 2021 to April 2023. The relationships between age, sex, pupil diameter, and higher-order corneal aberrations were examined and mean values for PPT measurements were compared between the groups. There was no difference in glare between the two groups. The halo was larger and thicker, and the starburst was larger and stronger in the Synergy group (P

Purpose: The aim of this study was to determine the effects of 2% pilocarpine ophthalmic solution on the depth of field and the pupil size of human eye in the presbyopic population. Settings and Design: Prospective experimental study. Methods: The prospective study included 120 presbyopic people aged between 40 and 55. All willing subjects underwent a comprehensive eye examination that included measuring the visual acuity for distance and near, retinoscopy, refraction, anterior and posterior segment examination, depth of field, and pupil size in room illumination. Following a preliminary examination, 2% pilocarpine ophthalmic solution was instilled in both eyes, and after various intervals of 15, 30, and 45 min, the depth of field and the pupil size were measured. Results: Before instillation of 2% pilocarpine solution, the mean pupil size was 0.34 mm with a standard deviation (SD) of ±0.37. After instillation, the mean pupil size changed to 2.20, 1.91, and 1.57 mm with SD of ±0.43, ±0.27, and ±0.34 mm, respectively, in 15, 30, and 45 min time intervals. Initial mean depth of field also changed from 1.76 D (SD ± 0.20) to 1.72, 1.65, and 1.59 D with SD of ±0.20, ±0.16, and ±0.22 D, respectively, in 15, 30, and 45 min time intervals. Conclusion: The study concludes that pupillary miotics create a pinhole effect after the instillation of 2% pilocarpine ophthalmic drop, extending the depth of field. The effect was highly clinically significant at 45 min with a P value

Pupil size primarily changes to regulate the amount of light entering the retina, optimizing the balance between visual acuity and sensitivity for effective visual processing. However, research directly examining the relationship between pupil size and visual processing has been limited. While a few studies have recorded pupil size and EEG signals to investigate the role of pupil size in visual processing, these studies have predominantly focused on the domain of visual sensitivity. Causal effects of pupil size on visual acuity, therefore, remain poorly understood. By manipulating peripheral background luminance levels and target stimulus contrast while simultaneously recording pupillometry and EEG signals, we examined how absolute pupil size affects visual discrimination and visually evoked potentials (VEP) in a task using optotype mimicking the Snellen eye chart, the most common assessment of visual acuity. Our findings indicate that both higher background luminance levels and higher target contrast were associated with improved target discrimination and faster correct reaction times. Moreover, while higher contrast visual stimuli evoked larger VEPs, the effects of pupil size on VEPs were not significant. Additionally, we did not observe inter-individual correlations between absolute pupil size and discrimination performance or VEP amplitude. Together, our results demonstrate that absolute pupil size, regulated by global luminance level, played a functional role in enhancing visual discrimination performance in an optotype discrimination task. The differential VEP effects of pupil size compared to those of stimulus contrast further suggested distinct neural mechanisms involved in facilitating visual acuity under small pupils. [ABSTRACT FROM AUTHOR]

Mind wandering, an experience characterized by a reduced external focus of attention and an increased internal focus, has seen significant theoretical advancement in understanding its underlying cognitive processes. The levels-of-inattention hypothesis posits that in mind wandering, external attention is reduced in a graded fashion, reflecting different levels of weak versus deep attentional decoupling. However, it has remained unclear whether internal processing during mind wandering, and mindless reading in particular, requires effort and, if so, whether it is graded or distinct. To address this, we analyzed pupil size as a measure of cognitive load in the sustained-attention-to-stimulus task during text reading. We examined whether decoupled external attention is linked to an overall reduction in workload and whether internal focus of attention is graded or represents a distinct cognitive process. Overall, overlooking errors in the text was associated with a small pupil size, indicating reduced effortful processing. However, this effect varied with error type: overlooking high- or medium-level errors (weak decoupling) resulted in reduced pupil size, while overlooking low-level errors (deep decoupling) had no effect on pupil size. Moreover, detecting an error (at any processing level) elicited a task-evoked pupillary response, which was absent when it was overlooked. These findings suggest that weak decoupling reduces internal resource-demanding processing and are in line with the hypothesis that large pupils during deep decoupling may be associated with distinct states of effortful internal processing. They further support both the levels-of-inattention hypothesis and the notion that internal focus is a distinct mode of deeply decoupled processing. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to assess the optical quality of myopic and presbyopic IPCLs with different additional powers, and to investigate the effects of pupil size on the optical quality of these IPCLs using an in-vitro modulation transfer function (MTF) measurement system. Methods: Linear scatter functions (LSFs) were recorded using the OPAL Vector system and an eye phantom consisting of wet cells filled with a balanced salt solution. A myopic IPCL or a presbyopic IPCL was placed in the posterior chamber of this model. The MTF was calculated from the LSF using the fast Fourier transform techniques. The effective apertures were set at 2.0 to 5.0 mm in 1.0 mm steps. Results: The in-focus MTF values of the myopic IPCL and presbyopic IPCL with additional powers of + 2.0 and + 4.0 diopters at 100 cycles/mm for an effective aperture of 3.0 mm were 43%, 27%, and 24%, respectively. The in-focus MTF value of both myopic and presbyopic IPCLs was the highest when the effective aperture was set at 3.0 mm, and it gradually worsened when the effective aperture became larger than 3.0 mm at 20, 60, and 100 cycles/mm. Conclusions: Both myopic and presbyopic IPCLs provided excellent MTF values, but the additional power profile can deteriorate optical performance in presbyopic IPCL-implanted eyes, even with a low additional power. Pupil size can influence visual quality in IPCL-implanted eyes for both myopia and presbyopia. Key Messages: What is known: • Implantable phakic contact lens (IPCL) has been reported to be effective for the treatment of both myopia and presbyopia, with a noticeable advantage in reducing the patients' cost burden. • The optical properties of IPCL have not yet been thoroughly investigated, neither for myopic IPCLs nor for presbyopic IPCLs. What is new: • The MTF of presbyopic IPCL was slightly lower than that of myopic IPCL even with a low additional power. • The MTF values of both myopic and presbyopic IPCLs were the highest for a 3.0 mm-pupil size, with gradually worsened for a larger pupil size. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Eye movement alterations are effective biomarkers for Alzheimer's disease (AD). This study examines task‐evoked pupillary responses (TEPRs) as potential biomarkers of the mild cognitive impairment (MCI), the symptomatic stage preceding AD. METHODS: The prospective cohort study included 213 MCI patients and 514 cognitively normal controls (CNs). Participants performed a prosaccade (PS) or antisaccade (AS) task while their eye movements were tracked using a Tobii Pro Spectrum system. RESULTS: The CNs showed unique TEPRs linked to better performance, characterized by larger baselines, greater PS target‐onset variability, and smaller AS target‐onset variability. Conversely, for MCI patients, better performance was linked to larger AS target‐onset sizes. Furthermore, MCI patients displayed reduced dilation during the cue and target‐onset periods compared to CNs. DISCUSSION: MCI patients showed altered pupillary response patterns associated with cognitive task performance, highlighting the potential of oculomotor changes as a biomarker for early cognitive decline. Highlights: MCI patients displayed markedly smaller pupil dilation than CNs in response to cue and target stimuli.For MCI patients, larger pupil size upon target appearance during antisaccades correlated with better performance.Faster and more consistent prosaccades were linked to better performance in both groups.For MCI patients, the association between longer AS latencies and better performance was more pronounced than in CNs.Combined analysis of TEPRs and saccade performances in a sizeable cohort strengthens the generalizability of our findings to the broader MCI population. [ABSTRACT FROM AUTHOR]

The selection of relevant information from internal memory representations involves both voluntary process directed by endogenous factors such as task goals or intentions, and involuntary susceptibility to exogenous factors like stimulus features. Previous research has shown that competition between these endogenous and exogenous factors delays internal selection of task-relevant information. Nonetheless, it remains unclear whether task-irrelevant information is removed from or retained in working memory. Across two experiments, we investigated how this competition affects task-irrelevant working memory representations. By tracking pupillary signals after different retro-cues, we revealed that task-irrelevant information was maintained in working memory under guidance from either an anti retro-cue which creates a state of conflict between endogenous and exogenous selection mechanisms, or a null retro-cue, which relies solely on exogenous factors. In contrast, task-irrelevant information was dropped from working memory when guided by pro retro-cue that harmonizes endogenous and exogenous factors. These findings strengthen the view that retro-cue benefits derive from removing task-irrelevant information from memory, rather than the prioritization view that priority in the task-relevant information does not alter the state of task-irrelevant information. [ABSTRACT FROM AUTHOR]

Objective: To establish a methodology for objectively estimating the Lens Equatorial Plane (LEP) from clinical images, comparing LEP with dilated versus non‐dilated pupils. Methods: A cohort of 91 eyes from 60 patients undergoing preoperative assessments for cataract surgery was evaluated. Anterior Segment Optical Coherence Tomography (AS‐OCT) images were analysed under conditions of pharmacologically induced pupil dilation versus a non‐dilated pupil. Geometrical parameters, including LEP, intersection diameter (ID), lens thickness (LT), anterior and posterior lens thickness were automatically calculated by applying standard image processing techniques to clinical AS‐OCT images. Results: Significant differences in lens parameters, including LEP, were observed between dilated and non‐dilated conditions (all p < 0.001). A strong linear correlation was found across all geometrical variables under both conditions (r[LEP] = 0.64, r[ID] = 0.78, r[LT] = 0.99, all p < 0.001); enabling reliable correction of these differences. Conclusion: The study introduces an objective methodology for LEP calculation, emphasising the need to consider the eye's physiological state during preoperative measurements. Incorporating LEP into future intraocular lens (IOL) power calculation formulas and replacing the habitual effective lens position may potentially improve the accuracy of IOL power estimation and thus postoperative visual outcomes. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to determine the effects of 2% pilocarpine ophthalmic solution on the depth of field and the pupil size of human eye in the presbyopic population. Settings and Design: Prospective experimental study. Methods: The prospective study included 120 presbyopic people aged between 40 and 55. All willing subjects underwent a comprehensive eye examination that included measuring the visual acuity for distance and near, retinoscopy, refraction, anterior and posterior segment examination, depth of field, and pupil size in room illumination. Following a preliminary examination, 2% pilocarpine ophthalmic solution was instilled in both eyes, and after various intervals of 15, 30, and 45 min, the depth of field and the pupil size were measured. Results: Before instillation of 2% pilocarpine solution, the mean pupil size was 0.34 mm with a standard deviation (SD) of ±0.37. After instillation, the mean pupil size changed to 2.20, 1.91, and 1.57 mm with SD of ±0.43, ±0.27, and ±0.34 mm, respectively, in 15, 30, and 45 min time intervals. Initial mean depth of field also changed from 1.76 D (SD ± 0.20) to 1.72, 1.65, and 1.59 D with SD of ±0.20, ±0.16, and ±0.22 D, respectively, in 15, 30, and 45 min time intervals. Conclusion: The study concludes that pupillary miotics create a pinhole effect after the instillation of 2% pilocarpine ophthalmic drop, extending the depth of field. The effect was highly clinically significant at 45 min with a P value <0.001. [ABSTRACT FROM AUTHOR]

Touch is important for many aspects of our daily activities. One of the most important tactile characteristics is its perceived intensity. However, quantifying the intensity of perceived tactile stimulation is not always possible using overt responses. Here, we show that pupil responses can objectively index the intensity of tactile stimulation in the absence of overt participant responses. In Experiment 1 (n = 32), we stimulated three reportedly differentially sensitive body locations (finger, forearm, and calf) with a single tap of a tactor while tracking pupil responses. Tactile stimulation resulted in greater pupil dilation than a baseline without stimulation. Furthermore, pupils dilated more for the more sensitive location (finger) than for the less sensitive location (forearm and calf). In Experiment 2 (n = 20) we extended these findings by manipulating the intensity of the stimulation with three different intensities, here a short vibration, always at the little finger. Again, pupils dilated more when being stimulated at higher intensities as compared to lower intensities. In summary, pupils dilated more for more sensitive parts of the body at constant stimulation intensity and for more intense stimulation at constant location. Taken together, the results show that the intensity of perceived tactile stimulation can be objectively measured with pupil responses – and that such responses are a versatile marker for touch research. Our findings may pave the way for previously impossible objective tests of tactile sensitivity, for example in minimally conscious state patients. Touch is integral to many daily activities, with the intensity of touch being a crucial characteristic. We demonstrate that pupil responses provide an objective measure of perceived touch intensity. This novel marker has the potential to advance touch research, by providing previously unattainable objective tests of processing of tactile stimuli. [ABSTRACT FROM AUTHOR]

Purpose: To assess over 2 weeks, the effect of 3 different low concentrations of atropine on pupillary diameter and accommodative amplitude in children with myopia. Methods: Fifty-eight children with myopia [spherical equivalent (SE) of −0.50 diopters (D) or worse, astigmatism of less than or equal to 2.00 D] were randomly allocated to 3 groups receiving 0.01%, 0.02%, or 0.03% atropine eye drops, once nightly for 2 weeks. The primary outcome was the change from baseline in pupillary diameter and accommodative amplitude with each of the concentrations. Results: Fifty-seven participants (114 eyes), aged between 6 and 12 years, completed the 2-week trial (mean age 9.3 ± 1.7 years and mean SE −3.53 ± 1.79 D). After 2 weeks of use, all the 3 concentrations were found to have a statistically significant effect on both the pupillary diameter and accommodative amplitude. Accommodative amplitude reduced by an average of 5.23 D, 9.28 D, and 9.32 D, and photopic pupil size increased by an average of 0.95 ± 1.05 mm, 1.65 ± 0.93 mm, and 2.16 ± 0.88 mm with 0.01%, 0.02%, and 0.03%, respectively. Of the eyes, a total of 5.3% and 5.9% of the eyes on 0.02% and 0.03% atropine had a mean residual accommodative amplitude of <5 D. The percentage of eyes having a pupillary dilation >3 mm were 4.8%, 10.5%, and 23.5% for 0.01%, 0.02%, and 0.03% atropine, respectively. Conclusions: Low-dose atropine had an effect on pupillary diameter and accommodative amplitude. With the highest concentration assessed, that is, 0.03% nearly 1 of 4 eyes had pupillary dilation of >3 mm. Clinical Trial Registration number: NCT03699423. [ABSTRACT FROM AUTHOR]

Abstract INTRODUCTION Eye movement alterations are effective biomarkers for Alzheimer's disease (AD). This study examines task‐evoked pupillary responses (TEPRs) as potential biomarkers of the mild cognitive impairment (MCI), the symptomatic stage preceding AD. METHODS The prospective cohort study included 213 MCI patients and 514 cognitively normal controls (CNs). Participants performed a prosaccade (PS) or antisaccade (AS) task while their eye movements were tracked using a Tobii Pro Spectrum system. RESULTS The CNs showed unique TEPRs linked to better performance, characterized by larger baselines, greater PS target‐onset variability, and smaller AS target‐onset variability. Conversely, for MCI patients, better performance was linked to larger AS target‐onset sizes. Furthermore, MCI patients displayed reduced dilation during the cue and target‐onset periods compared to CNs. DISCUSSION MCI patients showed altered pupillary response patterns associated with cognitive task performance, highlighting the potential of oculomotor changes as a biomarker for early cognitive decline. Highlights MCI patients displayed markedly smaller pupil dilation than CNs in response to cue and target stimuli. For MCI patients, larger pupil size upon target appearance during antisaccades correlated with better performance. Faster and more consistent prosaccades were linked to better performance in both groups. For MCI patients, the association between longer AS latencies and better performance was more pronounced than in CNs. Combined analysis of TEPRs and saccade performances in a sizeable cohort strengthens the generalizability of our findings to the broader MCI population.

Perceiving emotions from the movements of other biological entities is critical for human survival and interpersonal interactions. Here, we report that emotional information conveyed by point-light biological motion (BM) triggered automatic physiological responses as reflected in pupil size. Specifically, happy BM evoked larger pupil size than neutral and sad BM, while sad BM induced a smaller pupil response than neutral BM. Moreover, this happy over sad pupil dilation effect is negatively correlated with individual autistic traits. Notably, emotional BM with only local motion features retained could also exert modulations on pupils. Compared with intact BM, both happy and sad local BM evoked stronger pupil responses than neutral local BM starting from an earlier time point, with no difference between the happy and sad conditions. These results revealed a fine-grained pupil-related emotional modulation induced by intact BM and a coarse but rapid modulation by local BM, demonstrating multi-level processing of emotions in life motion signals. Taken together, our findings shed new light on BM emotion processing, and highlight the potential of utilizing the emotion-modulated pupil response to facilitate the diagnosis of social cognitive disorders.

BackgroundDaily use of low concentrations of atropine is recommended for children undergoing myopia control therapy. While the benefits of controlling myopia progression have been confirmed, the potential unwanted side effects on the ocular surface, pupil size, and quality of vision following the administration of 0.01% atropine have not been investigated.ObjectiveThis single-arm, self-control study aimed to investigate the short-term effects of 0.01% atropine topical eye drop (He Eye Hospital Co., Ltd., Shenyang, China) on pupil size and subjective quality of vision in participants with myopia. Each 3 mL vial of eye drops contains atropine (0.01%), sodium chloride (0.9%), and benzalkonium chloride (0.005%) in an aqueous solution.MethodsThirty-three adults (66 eyes) were recruited for the study. The mean age of the participants recruited for this study was 24.91 ± 3.36 years. This study is registered with Clinical Trials.gov (NCT06071260). Assessments were performed at baseline and 10 h, 14 h, and 18 h following the administration of 0.01% topical atropine drop (TAD). Mesopic pupil diameter (MPD), photopic pupil diameter (PPD), higher order aberration (HOA), non-invasive tear breakup time (NITBUT), tear meniscus height (TMH), tear film lipid layer (TFLL), and Redness score (RS). Subjective assessments included the quality of vision (QoV) and the ocular surface disease index (OSDI) questionnaires.ResultsFollowing the use of 0.01% atropine, PPD significantly increased at all the time points (p 0.05) at all time points.ConclusionDecreased TMH, dry eye symptoms, and visual symptoms will likely persist overnight but often diminish within 18 h after using 0.01% atropine eye drops.

Abstract Background Chronic resistance training and acute resistance exercises improve physical performance and can enhance cognitive performance. However, there is still uncertainty about the mechanism(s) responsible for cognitive improvement following resistance training and exercise. Recent findings suggest that resistance exercise has metabolic as well as cognitive demands, which potentially activate similar neural circuitry associated with higher-order cognitive function tasks. Exercising on unstable devices increases the coordinative and metabolic demands and thus may further increase cognitive activation during resistance exercise. The measurement of pupil diameter could provide indications of cognitive activation and arousal during resistance exercise. Pupil dilation is linked to the activity in multiple neuromodulatory systems (e.g., activation of the locus coeruleus and the release of the neurotransmitter norepinephrine (LC-NE system)), which are involved in supporting processes for executive control. Therefore, the purpose of this study was to compare the cognitive activation measured by pupil diameter during an acute bout of resistance exercise on stable and unstable surfaces. Methods 18 participants (23.5 ± 1.5 years; 10 females) performed ten kettlebell squats in a preferred repetition velocity in stable and unstable (BOSU® Balance Trainer) ground conditions. Pupil diameter was recorded with eye tracking glasses (SMI ETG) during standing (baseline) and during squatting. Raw pupil data were cleaned of artifacts (missing values were linearly interpolated) and subjected to a subtractive baseline correction. A student t-test was used to compare mean pupil diameter between ground conditions. Results The mean pupil diameter was significantly greater during squats in the unstable condition than in the stable condition, t (17) = -2.63, p =.018, Cohen’s d Z = -0.62; stable: 0.49 ± 0.32 mm; unstable: 0.61 ± 0.25 mm). Conclusion As indicated by pupil dilation, the use of unstable devices can increase the cognitive activation and effort during acute bouts of resistance exercise. Since pupil dilation is only an indirect method, further investigations are necessary to describe causes and effects of neuromodulatory system activity during resistance exercise. Resistance training with and without surface instability can be recommended to people of all ages as a physically and cognitively challenging training program contributing to the preservation of both physical and cognitive functioning.

This study examines the relationship between cosmetic packaging color and consumer attention by analyzing changes in pupil size using eye-tracking technology. A controlled experiment with 25 participants (mean age: 24.7 ± 3 years, 14 males and 11 females) was conducted to investigate the impact of eight packaging colors (black, white, blue, yellow, orange, turquoise, pink, and sky blue) on pupil dilation during gaze fixation and movement. Pupil size data were analyzed using SAS 9.4, with T-tests used to determine significant differences across colors. The results revealed that pink packaging elicited significantly larger pupil sizes during fixation, indicating heightened attention, while black, white, blue, and orange led to smaller pupil sizes when fixated, suggesting greater focus on the surrounding environment rather than the packaging. In contrast, yellow and turquoise exhibited no significant differences in pupil size during fixation and movement. Additionally, the study highlights that gaze fixation is a more meaningful indicator of attention than gaze movement, as fixation reflects focused interest in specific stimuli. The findings suggest that pink packaging is most effective in attracting consumer attention, while black, white, blue, and orange are better suited for enhancing focus on the surrounding environment. These insights emphasize the growing importance of packaging design in influencing consumer behavior, particularly through color selection. This study contributes to marketing practices by providing empirical evidence for the visual impact of packaging colors, offering valuable guidance for cosmetic industry practitioners. Future research should expand sample sizes and explore additional packaging attributes, such as shape and material, to derive more comprehensive insights.

AbstractWith the increasing popularity and unparalleled ubiquity of smartphones, researchers in various fields are designing and developing novel applications for this platform as part of the solution to the challenging problems they face. Usability lies at the core of the user experience of such applications. However, the assessments used are often limited to summative and post-event methods, which can overlook subtle yet impactful issues. Objective and instantaneous measures of cognitive workloads provide a solution to this shortcoming. Our previous research has established the reliability of maximum pupil dilation, measured with Tobii Pro Nano, as a preeminent indicator of cognitive workload surges in mobile application users. In this study, we used this measure to locate user cognitive workload peaks while using Conflict Solver and discovered subtle user interface issues that were not reported in the post-usability interview. A total of 30 participants completed a Conflict Solver usability experiment with two phases. In phase 1, the participants performed two “Add a Term” tasks on the original Conflict Solver, followed by a semi-structured interview about their experience with the application. A few subtle usability issues with a drop-down menu were detected through identifying user cognitive workload peaks. In phase 2, the same participants completed the same tasks on Conflict Solver with a redesigned and extended drop-down menu. The results showed that the new design solved the usability issues, and the participants became more favor the drop-down menu over the input box. In conclusion, including maximum pupil dilation into the usability assessment toolkit would provide a more objective and comprehensive usability assessment of a smartphone application. It can also be used to verify the successfulness of a user interface design solution. [ABSTRACT FROM AUTHOR]

Computer-based colour perception tests permit clinical assessment of cone-specific pathways, proving valuable for both identifying type and severity of hereditary colour vision deficiency and enhanced detection and monitoring of acquired colour deficiency from disease. Understanding the parameters that affect computer-based colour perception tests may enhance their veracity and clinical utility. Testing contrast sensitivity separately for the three cone systems enables a quantification of colour perception that can be clinically useful. This study evaluated the effects of pupil diameter and stimulus size on cone contrast sensitivity (CCS) assessed with the ColorDx (Konan Medical, Incorporated). Forty subjects, aged 21–31 years, who met the inclusion criteria participated. The tested eye was randomised. Two Landolt C sizes (2.68 degrees, 6/194, "small"; 8.58 degrees, 6/619, "large") were used, with one size and three chromaticities presented per block of trials. Stimulus presentation used the adaptive screening mode, sequentially determining contrast sensitivity for long-, medium-, and short-wavelength stimuli. Subjects were tested with their natural pupil size (range 4–5 mm diameter), then while viewing through a 2.5-mm artificial pupil. Parametric statistical tests were used for comparisons of performance across pupil size and stimulus size. Two-way within-subjects ANOVA indicates no interaction between pupil size and stimulus size for any of the three stimulus chromaticities. The main effect of stimulus size was significant for M-cone (F = 6.506, 2-tailed P =.015) and S-cone (F = 67.728, 2-tailed P <.001) stimuli. The main effect of pupil size was significant for all three stimulus chromaticities (L-cone: F = 227.161, M-cone: F = 249.979, S-cone: F = 89.371, 2-tailed P <.001 for all). Although CCS was reduced for all three chromaticities and both stimulus sizes with lower retinal illuminance, only S-wavelength cone contrast sensitivity was significantly different for the small versus large stimuli under the 2.5-mm pupil condition in this cohort. Whether CCS in older patients with naturally small pupils changes with an enlarged stimulus or dilated pupils remains to be explored. [ABSTRACT FROM AUTHOR]

Introduction: Individuals with Autism Spectrum Disorder (ASD) show atypical recognition of facial emotions, which has been suggested to stem from arousal and attention allocation. Recent studies have focused on the ability to perceive an average expression from multiple spatially different expressions. This study investigated the effect of autistic traits on temporal ensemble, that is, the perception of the average expression from multiple changing expressions. Methods: We conducted a simplified temporal-ensemble task and analyzed behavioral responses, pupil size, and viewing times for eyes of a face. Participants with and without diagnosis of ASD viewed serial presentations of facial expressions that randomly switched between emotional and neutral. The temporal ratio of the emotional expressions was manipulated. The participants estimated the intensity of the facial emotions for the overall presentation. Results: We obtained three major results: (a) many participants with ASD were less susceptible to the ratio of anger expression for temporal ensembles, (b) they produced significantly greater pupil size for angry expressions (withinparticipants comparison) and smaller pupil size for sad expressions (betweengroups comparison), and (c) pupil size and viewing time to eyes were not correlated with the temporal ensemble. Discussion: These results suggest atypical temporal integration of anger expression and arousal characteristics in individuals with ASD; however, the atypical integration is not fully explained by arousal or attentional allocation. [ABSTRACT FROM AUTHOR]

The pupil of the eye responds to various salient signals from different modalities, but there is no consensus on how these pupillary responses are integrated when multiple signals appear simultaneously. Both linear and nonlinear integration have been found previously. The current study aimed to reexamine the nature of pupillary integration, and specifically focused on the early, transient pupillary responses due to its close relationship with orienting. To separate the early pupillary responses out of the pupil time series, we adopted a pupil oscillation paradigm in which sensory stimuli were periodically presented. The simulation analysis confirmed that the amplitude of the pupil oscillation, induced by stimuli repeatedly presented at relatively high rates, can precisely reflect the early, transient pupillary responses without involving the late and sustained pupillary responses. The experimental results then showed that the amplitude of pupil oscillation induced by a series of simultaneous audiovisual stimuli equaled to a linear summation of the oscillatory amplitudes when unisensory stimuli were presented alone. Moreover, the tonic arousal levels, indicated by the baseline pupil size, cannot shift the summation from linear to nonlinear. These findings together support the additive nature of multisensory pupillary integration for the early, orienting‐related pupillary responses. The additive nature of pupillary integration further implies that multiple pupillary responses may be independent of each other, irrespective of their potential cognitive and neural drivers. The current study tapped into the controversial issue of how pupillary responses to multisensory signals are integrated, and specifically focused on the early, transient pupillary responses due to its close relationship with orienting. Using a simulation analysis and a pupil oscillation paradigm, we demonstrated a linear integration of the early pupillary responses. [ABSTRACT FROM AUTHOR]

Purpose: To study the effect of low-dose topical atropine eye drops (0.01%) in slowing myopia progression in school-age children. Methods: This was a prospective randomized controlled study, in children in the age group of 5–15 years, with myopic refractive error (spherical equivalent) between −1.0D and −5.0D at the time of presentation. A total of 100 patients were studied and randomly divided into two groups of 50 each: the control group and the atropine group. They were followed up 3 monthly for cycloplegic refraction, axial length (AL), pupil size, accommodation, and binocular stereopsis for near for a time period of 2 years. Results: Over a period of 2 years, there was a statistically significant decrease in the progression of myopic spherical equivalent and the AL in the atropine group. The accommodation and binocular stereopsis were comparable in both the groups. There was an average 0.7 mm increase in pupillary size posttreatment in the atropine group. Conclusions: The results of our study indicated that topical atropine (0.01%) is effective in retarding myopia progression at the end of 2 years of treatment. No child experienced allergic reaction, difficulty in reading, or photophobia during the trial period. Thus, atropine eye drops (0.01%) can be considered safe and efficacious in reducing the progression of myopia.

Arousal level is thought to be a key determinant of variability in cognitive performance. In a recent study, Beerendonk, Mejías et al. show that peak performance in decision-making tasks is reached at moderate levels of arousal. They also propose a neurobiologically informed computational model that can explain the inverted-U-shaped relationship. [ABSTRACT FROM AUTHOR]

Background: There is a growing interest to understand the neurobiological mechanisms that drive the positive associations of physical activity and fitness with measures of cognitive performance. To better understand those mechanisms, several studies have employed eye-based measures (e.g., eye movement measures such as saccades, pupillary measures such as pupil dilation, and vascular measures such as retinal vessel diameter) deemed to be proxies for specific neurobiological mechanisms. However, there is currently no systematic review providing a comprehensive overview of these studies in the field of exercise-cognition science. Thus, this review aimed to address that gap in the literature. Methods: To identify eligible studies, we searched 5 electronic databases on October 23, 2022. Two researchers independently extracted data and assessed the risk of bias using a modified version of the Tool for the assEssment of Study qualiTy and reporting in EXercise (TESTEX scale, for interventional studies) and the critical appraisal tool from the Joanna Briggs Institute (for cross-sectional studies). Results: Our systematic review (n = 35 studies) offers the following main findings: (a) there is insufficient evidence available to draw solid conclusions concerning gaze-fixation-based measures; (b) the evidence that pupillometric measures, which are a proxy for the noradrenergic system, can explain the positive effect of acute exercise and cardiorespiratory fitness on cognitive performance is mixed; (c) physical training- or fitness-related changes of the cerebrovascular system (operationalized via changes in retinal vasculature) are, in general, positively associated with cognitive performance improvements; (d) acute and chronic physical exercises show a positive effect based on an oculomotor-based measure of executive function (operationalized via antisaccade tasks); and (e) the positive association between cardiorespiratory fitness and cognitive performance is partly mediated by the dopaminergic system (operationalized via spontaneous eye-blink rate). Conclusion: This systematic review offers confirmation that eye-based measures can provide valuable insight into the neurobiological mechanisms that may drive positive associations between physical activity and fitness and measures of cognitive performance. However, due to the limited number of studies utilizing specific methods for obtaining eye-based measures (e.g., pupillometry, retinal vessel analysis, spontaneous eye blink rate) or investigating a possible dose–response relationship, further research is necessary before more nuanced conclusions can be drawn. Given that eye-based measures are economical and non-invasive, we hope this review will foster the future application of eye-based measures in the field of exercise-cognition science.

Objectives:To investigate the effects of pupil diameter on the evaluation of lens and corneal densitometry measured by Scheimpflug tomography.Materials and Methods:This cross-sectional and comparative study used the right eyes of 32 participants. Corneal and lenticular optical densitometries, corneal volume, anterior segment volume, and anterior chamber depth measurements were taken with the Scheimpflug imaging system when the pupils were mid-dilated and fully dilated. The results were statistically compared.Results:The mean lens density was 19.20±3.05 when the pupils were mid-dilated (mean pupil diameter 2.98±0.89 mm) and 23.25±3.88 at full dilation (mean pupil diameter 5.01±0.92 mm) (p

Purpose: To analyse and compare image acuity for different refractive errors generated by either altering axial length or corneal curvature and using three human eye models with two pupil sizes. Methods: Three different eye models, Liou‐Brennan, Goncharov and Navarro, were used. Simulations were made (using Ansys Zemax OpticStudio 22.3) for real pupil sizes of 3 and 6 mm with refractive errors ranging from −2 to +2 D in 0.25 D increments. Refractive errors were simulated by varying axial length or corneal curvature. Root mean square (RMS) values were used to determine image acuity. Results: For the 3‐mm pupil, all models gave similar results, with the Navarro model having slightly higher RMS values for the emmetropic eye. For the 6‐mm pupil, the Liou‐Brennan and Goncharov eye models gave similar results, with RMS values lower than for the Navarro eye model. The highest RMS value was visible in the axial length‐induced refractive errors. Refractive errors generated by altering corneal curvature give smaller RMS values than those generated by altering axial length. The axial length and corneal radius simulations indicate a wide spread of results for myopic, hyperopic and emmetropic eyes. There are multiple outcomes that give the same refractive error, even within a single‐eye model. The axial length/corneal curvature ratio showed a higher ratio for myopes than hyperopes for every model. Conclusions: The influence of refractive error on image acuity varied depending on the simulation method of refractive error and the model used. The origins of refractive error and the influence it has on image acuity need further investigation. As models become more sophisticated, personalised and biologically relevant, they will better represent the image acuity of the eye for varying refractive errors, ethnicities, ages and pupil sizes. [ABSTRACT FROM AUTHOR]

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Purpose: To evaluate changes in pupil size, ocular wavefront aberrations (WA), and accommodation in healthcare workers after 4-h usage of Filtering Facepiece class 3 (FFP3) masks. Material and Methods: This prospective study included 22 healthy healthcare workers. Pupil size, ocular WA, and accommodation changes before and after FFP3 mask usage were evaluated using a Hartmann Schack aberrometer. Accommodative responses to stimulus ranging from 0 to 5 diopters (D) in increments of 0.5 D were assessed. Ocular high-order aberrations (HOAs) were recorded at baseline and at every accommodative stimulus. Oxygen saturation (SpO2) was measured by pulse oximetry before and after the mask usage. Results: The mean age was 36.6 ± 8.5 years. The SpO2 significantly decreased from 98.95 to 97.95% after usage of the FFP3 mask (p < 0.001). The mean pupil size did not significantly differ before (6.22 ± 0.75 mm) and after (6.38 ± 0.83 mm) the 4-h mask usage (p = 0.093). The mean total RMS of the total HOAs was 0.36 ± 0.17 before and 0.39 ± 0.15 after the mask usage (p = 0.071). Post-mask accommodation showed a significant decrease at the 2 D (p = 0.041), 2.5D (p = 0.022), and 3 D (p = 0.025) stimuli. Conclusion: The present study shows that after 4 h-usage of FFP3 mask, both SpO2 and accommodative response to increasing stimuli might be significantly decreased. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of defocus and pupil size on subjective (visual acuity [VA]) and objective (electrophysiology) descriptors of human vision and their effect on binocular visual performance by means of neural binocular summation (BS). Methods: Fifteen healthy young subjects were recruited in this crossover study. Pattern electroretinogram (PERG) and visual evoked potentials (VEP) were measured under two levels of positive (+1.5 and +3.0 D) spherical and astigmatic defocus (axis 90°). Pupil size was controlled to reduce the inter‐individual variability factor. Results: Low‐ and high‐contrast VA showed poorer visual performance in the monocular versus the binocular condition. Positive BS (for VA) was higher with greater pupil size and higher levels of defocus. In the visual electrophysiology tests (i.e., VEP and PERG), peak time and amplitude were affected by pupil size and defocus. The increase in peak time was larger and the reduction in amplitude was more significant with greater levels of defocus and smaller pupil sizes. For the VEP, positive BS was found in all conditions, being stronger with larger amounts of defocus and pupil size (for the P100 amplitude). Significant negative correlations were observed between the P100 amplitude and VA BSs. Conclusion: Smaller pupil size and levels of defocus produced greater changes in cortical activity as evidenced by both the PERG and VEP. Considering these changes and the obtained positive BS, the mechanism could be initiated as early as the retinal processing stage, then being modulated and enhanced along the visual pathway and within the visual cortex. [ABSTRACT FROM AUTHOR]

Social and emotional cues from faces and voices are highly relevant and have been reliably demonstrated to attract attention involuntarily. However, there are mixed findings as to which degree associating emotional valence to faces occurs automatically. In the present study, we tested whether inherently neutral faces gain additional relevance by being conditioned with either positive, negative, or neutral vocal affect bursts. During learning, participants performed a gender‐matching task on face‐voice pairs without explicit emotion judgments of the voices. In the test session on a subsequent day, only the previously associated faces were presented and had to be categorized regarding gender. We analyzed event‐related potentials (ERPs), pupil diameter, and response times (RTs) of N = 32 subjects. Emotion effects were found in auditory ERPs and RTs during the learning session, suggesting that task‐irrelevant emotion was automatically processed. However, ERPs time‐locked to the conditioned faces were mainly modulated by the task‐relevant information, that is, the gender congruence of the face and voice, but not by emotion. Importantly, these ERP and RT effects of learned congruence were not limited to learning but extended to the test session, that is, after removing the auditory stimuli. These findings indicate successful associative learning in our paradigm, but it did not extend to the task‐irrelevant dimension of emotional relevance. Therefore, cross‐modal associations of emotional relevance may not be completely automatic, even though the emotion was processed in the voice. This study provides new evidence for the transfer of affective processing to affective learning and complements previous research on the preferential processing of emotional stimuli. Our findings indicate that only task‐relevant stimulus features were robustly learned, although the task‐irrelevant emotional meaning of the same stimulus influenced online processing and behavior during learning. [ABSTRACT FROM AUTHOR]

The size of the eyes’ pupils determines how much light enters the eye and also how well this light is focused. Through this route, pupil size shapes the earliest stages of visual processing. Yet causal effects of pupil size on vision are poorly understood and rarely studied. Here we introduce a new way to manipulate pupil size, which relies on activation of intrinsically photosensitive retinal ganglion cells (ipRGCs) to induce sustained pupil constriction. We report the effects of both experimentally induced and spontaneous changes in pupil size on visual processing as measured through EEG. We compare these to the effects of stimulus intensity and covert visual attention, because previous studies have shown that these factors all have comparable effects on some common measures of early visual processing, such as detection performance and steady-state visual evoked potentials; yet it is still unclear whether these are superficial similarities, or rather whether they reflect similar underlying processes. Using a mix of neural-network decoding, ERP analyses, and time-frequency analyses, we find that induced pupil size, spontaneous pupil size, stimulus intensity, and covert visual attention all affect EEG responses, mainly over occipital and parietal electrodes, but—crucially—that they do so in qualitatively different ways. Induced and spontaneous pupil-size changes mainly modulate activity patterns (but not overall power or intertrial coherence) in the high-frequency beta range; this may reflect an effect of pupil size on oculomotor activity and/ or visual processing. In addition, spontaneous (but not induced) pupil size tends to correlate positively with intertrial coherence in the alpha band; this may reflect a non-causal relationship, mediated by arousal. Taken together, our findings suggest that pupil size has qualitatively different effects on visual processing from stimulus intensity and covert visual attention. This shows that pupil size as manipulated through ipRGC activation strongly affects visual processing, and provides concrete starting points for further study of this important yet understudied earliest stage of visual processing.

Background: Although the benefits of intracameral mydriatics have been established in healthy patients, their safety and efficacy in difficult subjects have yet to be determined. Aim: The aim of the study is to assess the safety and efficacy of topical and intracameral application of a combination of tropicamide, phenylephrine and lidocaine during phacoemulsification surgery. Setting: The study was done at the Department of ophthalmology at the University of Bhavnagar, Gujarat, India. Methods: A total of 50 patients were recruited patients who were operated with phacoemulsification surgery. During the intraoperative period, pupil seize was studied and eventual adverse events have been monitored. Also, comfort reported by patients and surgeons has been investigated. Results: It was observed that the intracameral drug combination did not have any impact on blood pressure, pulse rate as well as did not affect the Intra Ocular Pressure (IOP) dynamics and was successful in maintaining pupil size after its application during surgery. Conclusion: The combination also proved effective as an anaesthetic agent, which was proven by pain score findings, as the patients were comfortable and compliant enough to tolerate cataract surgery. Contribution: The mydriatic and anaesthetic combination is efficient enough used topically and intracamerally to carry out phacoemulsification surgery and has a better safety profile when compared with current practices.

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in children and adolescents. Traditional diagnosis methods of ADHD focus on observed behavior and reported symptoms, which may lead to a misdiagnosis. Studies have focused on computer-aided systems to improve the objectivity and accuracy of ADHD diagnosis by utilizing psychophysiological data measured from devices such as EEG and MRI. Despite their performance, their low accessibility has prevented their widespread adoption. We propose a novel ADHD prediction method based on the pupil size dynamics measured using eye tracking. Such data typically contain missing values owing to anomalies including blinking or outliers, which negatively impact the classification. We therefore applied an end-to-end deep learning model designed to impute the dynamic pupil size data and predict ADHD simultaneously. We used the recorded dataset of an experiment involving 28 children with ADHD and 22 children as a control group. Each subject conducted an eight-second visuospatial working memory task 160 times. We treated each trial as an independent data sample. The proposed model effectively imputes missing values and outperforms other models in predicting ADHD (AUC of 0.863). Thus, given its high accessibility and low cost, the proposed approach is promising for objective ADHD diagnosis. [ABSTRACT FROM AUTHOR]

• There is insufficient evidence available to make solid conclusions concerning gaze-fixation-based measures. • The current evidence on the relationships between pupillometric indices, as proxies of the noradrenergic system, acute physical exercise, cardiorespiratory fitness, and cognitive performance is mixed. • Physical training- or fitness-related changes of the cerebrovascular system (i.e., operationalized via changes in retinal vasculature) are, in general, positively associated with cognitive performance improvements. • Acute and chronic physical exercises have a positive effect on oculomotor-based measures of executive function (i.e., operationalized via antisaccade tasks). • The positive association between cardiorespiratory fitness and cognitive performance is partly mediated by the dopaminergic system operationalized via the spontaneous eye-blink rate. There is a growing interest to understand the neurobiological mechanisms that drive the positive associations of physical activity and fitness with measures of cognitive performance. To better understand those mechanisms, several studies have employed eye-based measures (e.g., eye movement measures such as saccades, pupillary measures such as pupil dilation, and vascular measures such as retinal vessel diameter) deemed to be proxies for specific neurobiological mechanisms. However, there is currently no systematic review providing a comprehensive overview of these studies in the field of exercise-cognition science. Thus, this review aimed to address that gap in the literature. To identify eligible studies, we searched 5 electronic databases on October 23, 2022. Two researchers independently extracted data and assessed the risk of bias using a modified version of the Tool for the assEssment of Study qualiTy and reporting in EXercise (TESTEX scale, for interventional studies) and the critical appraisal tool from the Joanna Briggs Institute (for cross-sectional studies). Our systematic review (n = 35 studies) offers the following main findings: (a) there is insufficient evidence available to draw solid conclusions concerning gaze-fixation-based measures; (b) the evidence that pupillometric measures, which are a proxy for the noradrenergic system, can explain the positive effect of acute exercise and cardiorespiratory fitness on cognitive performance is mixed; (c) physical training- or fitness-related changes of the cerebrovascular system (operationalized via changes in retinal vasculature) are, in general, positively associated with cognitive performance improvements; (d) acute and chronic physical exercises show a positive effect based on an oculomotor-based measure of executive function (operationalized via antisaccade tasks); and (e) the positive association between cardiorespiratory fitness and cognitive performance is partly mediated by the dopaminergic system (operationalized via spontaneous eye-blink rate). This systematic review offers confirmation that eye-based measures can provide valuable insight into the neurobiological mechanisms that may drive positive associations between physical activity and fitness and measures of cognitive performance. However, due to the limited number of studies utilizing specific methods for obtaining eye-based measures (e.g., pupillometry, retinal vessel analysis, spontaneous eye blink rate) or investigating a possible dose–response relationship, further research is necessary before more nuanced conclusions can be drawn. Given that eye-based measures are economical and non-invasive, we hope this review will foster the future application of eye-based measures in the field of exercise-cognition science. [Display omitted] [ABSTRACT FROM AUTHOR]

Accurately recognizing facial expressions is essential for effective social interactions. Non-human primates (NHPs) are widely used in the study of the neural mechanisms underpinning facial expression processing, yet it remains unclear how well monkeys can recognize the facial expressions of other species such as humans. In this study, we systematically investigated how monkeys process the facial expressions of conspecifics and humans using eye-tracking technology and sophisticated behavioral tasks, namely the temporal discrimination task (TDT) and face scan task (FST). We found that monkeys showed prolonged subjective time perception in response to Negative facial expressions in monkeys while showing longer reaction time to Negative facial expressions in humans. Monkey faces also reliably induced divergent pupil contraction in response to different expressions, while human faces and scrambled monkey faces did not. Furthermore, viewing patterns in the FST indicated that monkeys only showed bias toward emotional expressions upon observing monkey faces. Finally, masking the eye region marginally decreased the viewing duration for monkey faces but not for human faces. By probing facial expression processing in monkeys, our study demonstrates that monkeys are more sensitive to the facial expressions of conspecifics than those of humans, thus shedding new light on inter-species communication through facial expressions between NHPs and humans. [ABSTRACT FROM AUTHOR]

Difficulties in face recognition contribute to social‐cognitive problems in autistic children. Evidence on behavioral interventions targeting this cognitive domain is limited. In non‐autistic individuals, a single exercise session is known to elicit temporary benefits for several cognitive functions. Our study investigates whether acute aerobic exercise influences face recognition in autistic children. In a randomized order, 29 participants completed a 20‐min moderately‐intense cycling bout on an ergometer and a control condition. Before and after each condition, participants categorized Mooney faces and instruments during a computerized cognitive task. Simultaneously, the N170 component of event‐related potentials and pupil size were recorded using electroencephalography and eyetracking, respectively. As indicated by a greater increase of reaction time in the exercise compared to the control condition, the results revealed impaired face recognition following aerobic exercise. This effect was accompanied by a lower decrease of the positive N170 amplitude and a trend towards a greater constriction of the pupil size in the exercise compared to the control condition. Our findings highlight the interplay of the physiological state and face recognition in autistic children. Exercise‐induced impairments in this social‐cognitive ability may be due to an interference with the learning effect that is typically seen for the structural encoding of faces. Lay Summary: Our findings indicate that a single aerobic exercise session temporarily impairs the ability to recognize faces in autistic children. On a neuronal level, this is due to a blocking of a learning effect that can be expected in difficult face recognition tasks. Following exercise, autistic children may experience an arousal level that is disadvantageous for social communication. [ABSTRACT FROM AUTHOR]

PURPOSE: It is a well-known fact that caffeine is an autonomic stimulant, which is said to have a significant effect on visual performance. This study was planned to investigate the effect of caffeine on the amplitude of accommodation and pupil size in adults. MATERIALS AND METHODS: An experimental study was conducted on 54 healthy individuals in the age range of 27–39 years. All the individuals underwent comprehensive eye examinations and were given caffeine through hot coffee (4 mg/kg). Push up method was used to measure accommodative amplitude (AOA) and pupil size was measured using millimeter scale, at baseline (before consuming coffee) and at 20, 40, and 60 min after consumption of coffee. All the measurements were taken on a random eye selected prior to the study. RESULTS: After consumption of caffeine, the AOA and pupil size showed a significant increase (P < 0.001) after 40 and 60 min. AOA elevated from 9.76 standard deviation (SD) ± 1.46D at baseline to 10.79 SD ± 1.55D at 60 min. Similarly, increment in pupil size from 3.53 SD ± 0.77 mm from baseline to 4.20 SD ± 0.77 mm after 60 min was recorded. There was no correlation found between AOA and pupil size at any point of time (r < 0.2). CONCLUSION: AOA and pupil size are affected in adults after caffeine consumption and it is important to take into account the history related to caffeine consumption before ocular and orthoptic evaluation. It can influence and alter the measurements recorded.

Pupil dilation is considered an index of cognitive effort, as the pupil typically dilates as the cognitive load increases. In this paper, we evaluated whether older adults demonstrate increased pupil size when performing tasks requiring cognitive inhibition. We invited 44 older and 44 younger adults to perform the Stroop task while their pupil dilation was recorded with eye-tracking glasses. The dependent variables were the number of accurate responses on the Stroop task as well as pupil size in the three conditions of the task (i.e., color naming, word reading, and the interference condition). The results demonstrated less accurate responses in the interference condition than in the color-naming or word-reading conditions, in both older and younger adults. Critically, larger pupil dilation was observed in the interference condition than in the color-naming and word-reading conditions, in both older and younger adults. This study demonstrates that pupil dilation responds to cognitive effort in normal aging, at least in the interference condition of the Stroop task. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the effects of pupil diameter on the evaluation of lens and corneal densitometry measured by Scheimpflug tomography. Materials and Methods: This cross-sectional and comparative study used the right eyes of 32 participants. Corneal and lenticular optical densitometries, corneal volume, anterior segment volume, and anterior chamber depth measurements were taken with the Scheimpflug imaging system when the pupils were mid-dilated and fully dilated. The results were statistically compared. Results: The mean lens density was 19.20±3.05 when the pupils were mid-dilated (mean pupil diameter 2.98±0.89 mm) and 23.25±3.88 at full dilation (mean pupil diameter 5.01±0.92 mm) (p<0.001). The mean corneal density was 16.15±0.99 with mid-dilated pupils and 16.38±0.95 with fully dilated pupils (p=0.065). Anterior chamber depth and anterior segment volume measurements increased with larger pupil diameter (p<0.05). Conclusion: The lens densitometry values increased with an increase in pupil diameter. The corneal density measurements increased minimally but the differences were not statistically significant. This study revealed that lens densitometry was significantly affected by pupil diameter. [ABSTRACT FROM AUTHOR]