Mean Pupil Diameter Research Articles

The effect of phacoemulsification on the intraocular pressure, anterior chamber and pupildiameter in patients with pseudoexfoliation syndrome

Aims: To evaluate the effect of phacoemulsification on the intraocular pressure, anterior chamber and pupil diameter in patients with pseudoexfoliation syndrome. Methods: 66 eyes of thirty-three patients who had pseudoexfoliation and underwent phacoemulsification enrolled in this retrospective study. The eyes divided two groups as a study group that with Pseudoexfoliation Syndrome (PES) or Pseudoexfoliation (PEX) glaucoma and the other eyes as a control group without PES or PEX glaucoma. The follow-up examinations were preoperatively and postoperatively on the first day, fourth day, first month, and three months. Best-Corrected Visual Acuity (BCVA), Intraocular Pressure (IOP), Anterior Chamber Depth (ACD) and Pupil Diameter (PD) were evaluated at each visit, and glaucoma medications were noted. Results: There was no statistically significant difference when compared preoperative and postoperative IOP values on the first day between two groups (p>0.05). The mean IOP postoperatively at 4th, 30th day and 3rd months, reduced according to preoperative values in the study group (P<0.05). Mean anterior chamber depth and pupil diameter were increased significantly at the final visit (p<0.001). Conclusion: Cataract surgery has a beneficial effect on patients with PEX including IOP, ACD and PD.

The significance of maps in video games for the interpretation of spatial situation

ABSTRACT This article examines the significance of the world map in video games for the interpretation of spatial situations. An example is the popular role-playing game The Witcher 3: Wild Hunt (TW3). Nowadays, most video games are characterized by the presence of a spatial aspect. The game world map is the most important navigational element of the game that the gamer can use. To this end, the authors decided to test the importance of the game world map in the context of analyzing different examples of spatial situations that appear in TW3 by the respondents. Eye movement tracking was chosen as the research method. The analysis was conducted using statistical tests. Both gamers and non-gamers of TW3, gamers and non-gamers in general, participated in the survey. Each subject was shown 5 movies (1 introductory movie, 4 movies in the main part of the study) from the gameplay of the game, in which the game world map was opened. After each video, a question was asked about both the gameplay and the game world map. It was found that familiarity with TW3, frequency of playing video games influenced the correctness and time of answering the questions asked. In addition, by analyzing mean pupil diameter it was found that the game world map and gameplay segments do not cognitively burden the users. By analyzing the duration of fixations and the number of fixations, differences in visual strategy were observed between the groups of test subjects.

Effects of topical 0.5% tropicamide and 1% atropine on pupil diameter, intraocular pressure, and tear production, in healthy pet rabbits.

To evaluate the effects of topical application of 0.5% tropicamide and 1% atropine on pupil diameter (PD), intraocular pressure (IOP), and tear production (TP) in healthy pet rabbits. Ten healthy client-owned rabbits. A prospective, randomized, blinded, crossover study was conducted. Each animal received one drop of 0.5% tropicamide or 1% atropine in a randomly selected eye. PD, IOP, and TP were evaluated before drug instillation and at 0.25 h, 0.5 h, 0.75 h, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 24 h, 36 h, 48 h, 60 h, and 72 h post-instillation. Data were analyzed using a paired two-sample repeated measures T-test with Bonferroni correction. In both tropicamide and atropine treated eyes, the mean PD significantly increased from 15 min until 12 h after treatment with a maximum PD at 45 min (+2.7 mm and + 2.4 mm respectively). Following tropicamide and atropine instillation, IOP increased significantly in treated eyes at 45 min (+2.9 mmHg) and 15 min (+5.2 mmHg) respectively, compared to untreated eyes. No significant effects were found on TP, in both tropicamide and atropine treated eyes at any time. No effects were observed in the untreated eyes on any of the parameters evaluated for both drugs. Topical treatment with 0.5% tropicamide and 1% atropine induced mydriasis in healthy pet rabbits and could be considered as effective options when mydriatic/cycloplegic drugs are required.

A Quantitative Method of Assessing the Hazard Perception of Drivers in Human–Machine Codriving Vehicles

Hazard perception, as a dynamic indicator, intuitively characterizes drivers’ ability to detect potential hazard events in complex driving environments. However, current quantitative research on the hazard perceptions of drivers in the human–machine codriving phase is lacking. A total of 30 drivers were recruited to carry out a driving simulator experiment, and a total of 8 risky driving scenarios were experienced. The physiological characteristics and eye movement characteristics of the drivers were collected. An expert evaluation method was selected to quantify the situational hazard degree (SHD). The questionnaire was used to collect the drivers’ subjective hazard evaluations (SHEs) of the scenarios. Paired samples t test and correlation analysis were adopted to screen the evaluation indexes of the drivers’ hazard perceptions. A gray near-optimal comprehensive evaluation model was established to quantify the human–machine codrivers’ hazard perceptions in various risky driving scenarios. The results show that the drivers’ SHEs increased with the SHD. The standard deviation of heart rate, mean pupil diameter, and mean fixation duration can be used as evaluation indexes for the human–machine codrivers’ hazard perceptions. The proposed quantitative method is expected to shift the development of human–machine codrivers’ hazard perception from qualitative analysis to quantitative calculation. The research results can provide a theoretical basis for increasing safety in the human–machine codriving phase, improving road safety and reducing the incidence of accidents.

Intracameral Anaesthetic Mydriatic Versus Topical Mydriasis in Pediatric Cataract Surgery: A Randomized Control Study

To compare pupil dynamics after using premixed intracameral anesthetic mydriatic combination (ICAM) of phenylephrine (0.31%), tropicamide (0.02%), and lidocaine (1%) versus topical mydriatic (TM) drops consisting of tropicamide 0.8%, phenylephrine 5%, and cyclopentolate 0.5% in pediatric cataract surgery. Randomized, masked, fellow eye-controlled trial. Tertiary eye care facility. Children ≤12 years of age with bilateral cataracts planned for surgery. One eye was randomized to receive ICAM and the other eye (control) TM drops. Commercially available ICAM that was injected at the beginning of surgery or TM 3 times at an interval of 30 minutes, 1 hour before the scheduled time of surgery. The other treatment was administered for the second eye cataract surgery. Pupil dynamics at various points of surgery were studied by a masked observer. Sixty-three patients (126 eyes) were randomized to receive ICAM in 1 eye (group 1) or TM drops (group 2). The mean age of the children in the study was 15.7 ± 24.3 months (range 3 months to 5 years). Adequate mydriasis with a single injection was achieved in 93.5% of patients in group 1 and 88.8% of patients in group 2 without additional pharmacotherapy or intervention. The mean pupillary diameter increased from 1.78 mm to 5.1 mm after injection of 1 unit of ICAM and from 1.75 mm to 6.06 mm with TM drops (P < .0001). The maximum pupillary dilation achieved was 6.06 ± 1.17 mm in group 1 and 6.75 ± 1.07 mm in group 2 (P = .004). The average change in pupillary size from injection of drug until the end of surgery was positive in group 1 (0.75 ± 0.98 mm) and negative in group 2 (-0.3348 ± 2.57 mm), ie, there was a relative miosis in group 2 toward the end of surgery (P = .001). Topical drugs achieved a larger maximum pupil size compared with ICAM. However, ICAM provided adequate and stable mydriasis without the need for augmentation compared with topical drops in children undergoing cataract surgery.

Semantic distance of icons: Impact on user cognitive performance and a new model for semantic distance classification

With the continuous development of human-computer interaction technologies and the widespread use of graphical interfaces, icons that represent various objects and functions have a particularly important role. This study investigates the effect of semantic distance of icons on cognitive performance through an eye-movement-based experiment which involves a visual search for icons. The findings show that the semantic distance of icons has a significant effect on cognitive performance. A higher cognitive performance is found with semantically close icons which can better capture user attention. In addition, we use eye-movement indicators that are highly correlated with semantic distance, including mean pupil diameter, mean gaze duration and initial gaze time of an AOI, and analyze the objective relationship between these three eye-movement indicators and the semantic distance of icons to establish a dataset. The dataset is used as input for a Gradient Boosting Decision Tree (GBDT), which is a machine learning-based method for classifying the semantic distance of the icons in this study. The output of the GBDT model is classifying the semantic distance as far and close, and the experimental results show that the accuracy of the model reaches 84.28% after a comparison with other types of classifiers, which is in good agreement with the experimental results. Therefore, the model can address the relevant application requirements and simplify the evaluation process of icons to a certain extent, which has great significance in the field of icon design.

Attentional Bias, Pupillometry, and Spontaneous Blink Rate: Eye Characteristic Assessment Within a Translatable Nicotine Cue Virtual Reality Paradigm.

Incentive salience processes are important for the development and maintenance of addiction. Eye characteristics such as gaze fixation time, pupil diameter, and spontaneous eyeblink rate (EBR) are theorized to reflect incentive salience and may serve as useful biomarkers. However, conventional cue exposure paradigms have limitations that may impede accurate assessment of these markers. This study sought to evaluate the validity of these eye-tracking metrics as indicators of incentive salience within a virtual reality (VR) environment replicating real-world situations of nicotine and tobacco product (NTP) use. NTP users from the community were recruited and grouped by NTP use patterns: nondaily (n=33) and daily (n=75) use. Participants underwent the NTP cue VR paradigm and completed measures of nicotine craving, NTP use history, and VR-related assessments. Eye-gaze fixation time (attentional bias) and pupillometry in response to NTP versus control cues and EBR during the active and neutral VR scenes were recorded and analyzed using ANOVA and analysis of covariance models. Greater subjective craving, as measured by the Tobacco Craving Questionnaire-Short Form, following active versus neutral scenes was observed (F1,106=47.95; P<.001). Greater mean eye-gaze fixation time (F1,106=48.34; P<.001) and pupil diameter (F1,102=5.99; P=.02) in response to NTP versus control cues were also detected. Evidence of NTP use group effects was observed in fixation time and pupillometry analyses, as well as correlations between these metrics, NTP use history, and nicotine craving. No significant associations were observed with EBR. This study provides additional evidence for attentional bias, as measured via eye-gaze fixation time, and pupillometry as useful biomarkers of incentive salience, and partially supports theories suggesting that incentive salience diminishes as nicotine dependence severity increases.

Evaluation of mental load using EEG and eye movement characteristics

Mental load is a major cause of human-induced accidents. In this study, an explosive impact sensitivity experiment was used to induce mental load. A combination of subjective questionnaires and objective prospective time-distance tests were used to judge whether subjects experienced mental load. Four indicators, namely, β, γ, mean pupil diameter, and fixation time were selected by statistical analysis and PCA for the construction of a mental load assessment model. The study found that the occipital lobe was the most sensitive to mental load, especially β and γ bands. Lastly, it was found that subjects showed different degrees of mental load for the same mental load induction task. The results of the study are applicable to the evaluation and monitoring of the mental characteristics of workers and provide a scientific basis for adjusting the mental load of workers over time to reduce the rate of accidents and enhance production efficiency.

Comparison of pupil dilation in manual small incision cataract surgery using topical versus intracameral mydriatic agents – A randomised controlled trial

Objectives: The purpose of this research is to assess and compare the efficacy of an intracameral mydriatic solution with conventional topical agents in the completion of manual small incision cataract surgery (MSICS) in a black population. Materials and Methods: This randomised controlled trial was conducted among 102 patients undergoing MSICS under sub-tenon’s block. Mydriasis in the topical group was achieved with a pre-operative topical dilating combination of tropicamide 0.8% and phenylephrine 5% while surgery was commenced in patients in the intracameral group without dilation, and mydriasis was achieved intraoperatively with an intracameral solution of lidocaine 0.5% and adrenaline 0.001%. Pupil sizes were measured serially, before, and at four different junctures during surgery. The proportion of patients needing supplementary mydriasis in either group was noted, as well as post-operative pinhole visual acuity (VA). Data analysis was carried out using the Statistical Package for the Social Sciences Statistical Product and Service Solutions(SPSS) version 25.0 (IBM, Chicago, Illinois). The level of statistical significance was set at P &lt; 0.05 at a 95% confidence interval. Results: Mean pupil diameter before dilating and blocking was 2.5 ± 0.6 mm in the topical group and 2.5 ± 0.7 mm in the intracameral group (P = 0.752). This increased to 7.7 ± 1.1 mm and 7.4 ± 0.8 mm, respectively (P = 0.134), after administering either mydriatic agents. After that, mean pupil diameter progressively reduced in both groups but was significantly higher in the intracameral group at each point of measurement (P &lt; 0.05). Postoperatively, there was no significant difference in the VA between the two groups (P &lt; 0.05). Conclusion: Using an intracameral mixture of lidocaine and adrenaline gives adequate mydriasis for the successful completion of MSICS without pre-operative dilation.

Effect of nadolol in treatment of induced ocular hypertension in rabbits

In glaucoma, as optic neuropathy gradually proceeds unnoticed by the patient, early detection and treatment is of paramount importance in arresting or controlling the progress of damage. To explore effects of topical nadolol on intraocular pressure (IOP) ocular hypertensive eyes of rabbits. A group of 36 males of the rabbits were included in this study. Induction of ocular hypertension was achieved by injection of hydroxy propyl methylcellulose in the anterior chamber of rabbits right eye. The present study was designed to evaluate the possible beneficial therapeutic effect. The included rabbits were divided into distilled water group, timolol (0.25% and 0.5%) groups, and nadolol (0.25% and 0.5%). Each of drug eye drops (including distilled water) were instilled into right eyes 3 times/day for 10 days therapeutically. The rabbits had been examined for the IOP, pupil diameter, light reflex, corneal reflex, and conjunctival redness prior to instillation of drugs and along the trial period. Results: Ocular hypotensive effects of nadolol (0.25%) and (0.5%) eye drops were more efficient than that of distilled water (P&lt;0.01). Furthermore, nadolol eye drop was more efficient than timolol eye drop (0.01&gt;P&gt;0.05) in its ocular hypotensive effect in both concentrations along the trial period. In both parts of the present study and regarding each of mean pupil diameter, light reflex, corneal reflex and conjunctival redness, nadolol (0.25% or 0.5%) eye drops had no significant adverse effect (P &gt; 0.05). Conclusions: Nadolol eye drops instilled 3 times / day had an obvious beneficial, safe, and tolerable therapeutic ocular hypotensive effects on hydroxy propyl methyl cellulose - induced ocular hypertension in rabbits.

Cataract surgery in children using intracameral mydriatic.

To study the pupil dynamics with premixed intracameral anesthetic mydriatic combination of phenylephrine (0.31%), tropicamide (0.02%), and lidocaine (1%) in pediatric cataract surgery. Consecutive children aged ≤12 years planned for cataract surgery were recruited. A commercially available premixed combination of phenylephrine (0.31%), tropicamide (0.02%), and lidocaine (1%) was injected at the beginning of surgery without any topical/infusion drugs for mydriasis. Pupil sizes at various points of surgery were studied. We recruited 75 patients with a mean age of 24.3 ± 33.4 months (range: 1 month-11 years). Adequate mydriasis with a single injection was achieved in 93.5% (n = 73 eyes of 70 patients) without additional pharmacotherapy or intervention. The mean pupillary diameter increased from 1.8 ± 0.79 to 6.1 ± 1.4 mm after injection (mean change of 4.2 ± 1.25 mm from baseline). The mean variability in pupillary diameter was 0.73 ± 1.3 mm. In five eyes, good dilatation was not possible even after repeat injection. Fixed-dose premixed intracameral injection is effective in pupil dilatation. It alleviates the need for any topical dilators or additional intraoperative supplementation for pediatric cataract surgery.

Resistance exercising on unstable surface leads to Pupil Dilation

BackgroundChronic 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.Methods18 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.ResultsThe 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 dZ = -0.62; stable: 0.49 ± 0.32 mm; unstable: 0.61 ± 0.25 mm).ConclusionAs 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.

Analysis of pupillary responses in pediatric patients with vitamin D deficiency.

To evaluate the effects of vitamin D deficiency on pupillary responses in the pediatric population. The study was conducted using data from the right eyes of 52 children with vitamin D deficiency and 52 healthy children. Measurements were taken under static and dynamic conditions with automatic pupillometry. Static measurements were performed at scotopic, mesopic, and photopic light intensities. The mean pupil dilation speed was calculated by observing the changes in pupil dilation over time according to dynamic measurements. Differences between patient and control groups were analyzed for the static and dynamic measurements and the mean pupil dilation speed. While the two groups were similar in terms of scotopic, mesopic, the first dynamic measurements, and the pupil dilation speed data (p > 0.05), a significant difference was found in the photopic conditions (p = 0.001). The mean pupil diameter of the patient group was 4.46 ± 0.928mm and 3.95 ± 0.556mm in the control group under photopic conditions. Pediatric patients with vitamin D deficiency have significantly larger pupil diameters in photopic conditions than healthy children. These results suggest that there is an autonomic dysfunction in vitamin D deficiency in the pediatric population, especially pointing to the parasympathetic system.

Pupil size measurements with a multifunctional aberrometer/coherence interferometer/tomographer and two infrared-based pupillometers.

To compare precision of pupil size measurements of a multifunctional device (Pentacam AXL Wave [Pentacam]) and 2 infrared-based pupillometers (PupilX, Colvard) and to compare repeatability of Pentacam and PupilX. Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany. Prospective, comparative trial. Pupil diameter of healthy eyes was measured with Colvard once and Pentacam without glare (WO) and with glare (WG), PupilX in 0, 1, and 16 lux 3 times each. In a second series, measurements with Pentacam WO and PupilX in 0.06 and 0.12 lux were assessed. 36 eyes of participants aged 21 to 63 years were included. Mean pupil diameter was 6.05 mm with Colvard, 5.79 mm (first series), 5.50 mm (second series) with Pentacam WO, 3.42 mm WG, 7.26 mm PupilX in 0, 4.67 mm 1, 3.66 mm 16, 6.82 mm in 0.06, and 6.39 mm in 0.12 lux. Measurements with Pentacam WO were significantly different to PupilX in 0, 0.06, 0.12, and 1 lux (all P < .001), but not to Colvard ( P = .086). Pupil size measured with Pentacam WG and PupilX in 16 lux was not significantly different ( P = .647). Consecutive measurements with Pentacam WO and WG had mean SD of 0.23 mm and 0.20 mm, respectively, and with PupilX 0.11 in 0, 0.24 mm 1, and 0.20 mm in 16 lux. Pentacam provided good assessment of pupil size but was not equivalent to PupilX in low lighting conditions. Repeatability was more favorable for Pentacam.

Evaluation of early period changes in intraocular pressure, ocular biometry and anterior segment after upper eyelid blepharoplasty.

To investigate the acute effects of upper eyelid blepharoplasty on intraocular pressure (IOP) and ocular biometric parameters. This prospective cross sectional study examined the eyes of 49 patients with dermatochalasis. Following a detailed ophthalmological examination, corneal topography was used to evaluate the eyes mesopic and photopic pupil diameter, anterior chamber depth, and corneal astigmatism on the day of surgery and on days first and seventh postoperatively. Ocular biometry was used to assess axial length and intraocular lens power. Goldmann applanation tonometry was used to measure intraocular pressure. Forty-nine eyes (26 males and 23 females) of 49 patients aged between 44 and 76years (mean 61 ± 7.9) were included in our study. The mean anterior chamber depth (ACD) was 2.90 ± 0.37mm preoperatively, 3.00 ± 0.29mm at postoperative day first, and 3.04 ± 0.29mm at postoperative day seventh, and the increase in anterior chamber depth was statistically significant (p < 0.001). The mean astigmatism values were measured as preoperative 0.73 ± 0.69 D, postoperative first day 0.93 ± 0.81 D, and postoperative seventh day 1.26 ± 0.90 D. The increase in astigmatism values was statistically significant (p < 0.001).The mean pupil diameter measurements in the mesopic environment were 4.20 ± 0.61mm preoperatively, 4.40 ± 0.59mm on the first postoperative day, and 4.39 ± 0.57mm on the seventh postoperative day, and there was a statistically significant difference between the three measurements (p = 0.03). The mean IOP measurements of the patients were 15.91 ± 3.51mmHg preoperatively, 16.81 ± 3.36mmHg on the first postoperative day, and 16.97 ± 3.13mmHg on the seventh postoperative day. The increase between these three measurements was statistically significant (p = 0.013). This study includes important insights into the potential acute phase impact of blepharoplasty surgery on ocular findings. Patients undergoing upper eyelid surgery should be informed about the possible change in ocular biometric parameters, intraocular pressure, and pupil diameter.

Sutureless intrascleral intraocular lens fixation and modified iris cerclage pupilloplasty for aphakia and traumatic mydriasis.

To evaluate the safety and efficacy of sutureless intrascleral intraocular lens (IOL) fixation combined with modified iris cerclage pupilloplasty for treating aphakia and traumatic mydriasis. Five patients with aphakia and traumatic mydriasis were operated on by the same surgeon. All patients underwent sutureless intrascleral IOL fixation combined with modified iris cerclage pupilloplasty and were followed up for ≥6 months. Best-corrected visual acuity (BCVA) was measured using the logarithm of the minimum angle of resolution (logMAR). BCVA, intraocular pressure (IOP), pupil diameter, and corneal endothelial cell count (CECC) preoperatively and postoperatively were statistically analyzed. The pupil shape, photophobia, IOL position, and surgical complications were evaluated. The mean BCVA was significantly improved 6 months postoperatively (0.26 ± 0.17 logMAR, P = 0.042) than preoperatively (0.50 ± 0.30 logMAR). No significant difference was observed between the preoperative and postoperative IOP (P = 0.138). The mean pupil diameter significantly reduced postoperatively than preoperatively (3.44 ± 0.35 mm vs. 7.28 ± 0.35 mm, P = 0.043). There was no significant decrease in CECC postoperatively (P = 0.225). The pupil shape was round-like, and photophobia disappeared in all patients. No intraoperative or postoperative complications occurred. Sutureless intrascleral IOL fixation combined with modified iris cerclage pupilloplasty is a safe and efficient procedure for treating aphakia traumatic mydriasis patients without sufficient capsular support.

On-eye centration of soft contact lenses.

To evaluate the relative positions of modern soft contact lenses (SCLs) relative to the limbus/cornea and the pupil. Sixty images of the anterior eyes of 101 subjects were acquired over 10 s while participants fixated the centre of the camera lens located 33 cm in front of the eye in a well-lit (300 lux) clinic. Custom validated image analysis software was used to locate the boundaries of the contact lenses, pupils and corneas (limbus). Horizontal and vertical relative positions of the contact lens, pupil and limbus were calculated from the fitted boundaries. The mean (standard deviation) pupil and corneal diameters for all subjects were 3.84 mm, (0.83) and 11.97 mm (0.48), respectively. The mean [95% confidence interval] pupil centre was located 0.28 mm [0.26, 0.30] nasally and 0.07 mm [0.05, 0.10] superiorly to the corneal centre. Consistent with clinical observations, the contact lenses centred accurately relative to the corneal centre both nasally 0.04 mm [0.01, 0.07] and inferiorly -0.01 mm [-0.06, 0.03]. However, regardless of the eye, the contact lens was significantly (p < 0.001) decentred relative to the pupil centre both temporally -0.23 mm [-0.26, -0.20] and inferiorly -0.08 mm [-0.12, -0.04]. Decentration magnitudes were significantly correlated between the right and left eyes. Spherical SCLs centred well on the cornea but temporally and inferiorly from the primary line of sight (pupil centre), due to the differences in the location of the pupil and corneal centres. Contrary to some previous reports, there was no evidence that lens optics or material affected lens centration significantly.

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.

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.

Pupil Dilation as an Index of Examinee's Cognitive Load in Answering a Mathematics Question: A Comparison Study of Different Approaches

ABSTRACTStudies have demonstrated that task‐evoked pupillary responses (TEPRs) can be adopted to measure the examinee's cognitive load. This study compared three approaches for the measurement of TEPRs, mean pupil diameter, mean pupil dilation, and mean percentage of pupil dilation, to determine the best‐fit measuring method. The valid participants of this study were eight sixth‐grade elementary students. The experimental materials used were two mathematics questions with differing difficulty. The generalized estimating equation (GEE) was employed to compare the goodness of fit of each approach. The results revealed that the measurement of TEPRs based on the mean percentage of pupil dilation measured every 4 s provided the best fit.