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Athletes, particularly ball game players, benefit from focusing on fast-moving visual targets. In this study, we hypothesized that athletes, specifically professional basketball players, exhibit more accurate saccadic eye movements compared to non-athletes. To test this hypothesis, we assessed the eye movements of eight female professional basketball players from the Niigata Albirex BB (basketball player group) and compared them to eight sex-matched healthy volunteers from a previous study. Eye movements were measured using the Eye Score device. The visual target moved continuously for 20 s at a speed of 100 degrees/s in regular triangular wave-like movements horizontally. The subjects tracked the visual targets with maximum accuracy. The total amplitudes of evoked eye movements during tracking were 37.96 ± 0.82 for the basketball player group and 27.74 ± 2.55 deg (mean ± SEM) for the non-athlete group, indicating a significant difference. These findings suggest that basketball players may achieve accurate saccades by employing predictive saccades. The saccades of the basketball players were concentrated at the fifth frame (0.17 s after the onset of target motion), exhibiting a more peaked distribution than the normal curve. The results imply that athletes may execute predictive saccades when tracking targets with predictable movements, even outside of actual competition. [ABSTRACT FROM AUTHOR]

A predictive model of tractor driver's eye positions based on the anthropometric parameters and tractor cab layout parameters was established using the statistical approach. To our knowledge, this model is the first published predictive model of tractor drivers' eye positions that takes account of their body dimensions and tractor types. In order to predict the distribution of the drivers' eye positions precisely, the fore-and-aft positions of the driving seat determined by 180 tractor drivers in three different tractors and the relative positions of the eyes to the designated reference points were recorded to quantitatively demonstrate the distribution rule of their eye positions. The multiple linear regression and principal component analysis were adopted to processing the feature parameters of human and tractor, and the prediction effect of the model was assessed according to the proportion of the driver's eye positions from side view those were within the range of the eyellipse model. The experimental result revealed that the centroid positions and principal axis dip angle of the model differed from each other respectively, while the axis lengths were the same. The principal axis dip angle was horizontal or oblique forward-and-upward. And the tractor layout parameters had a significant impact on the centroid coordinate and principal axis dip angle of the model, while the dimension of the model was associated with the anthropometric parameters mainly. The prediction accuracy of the model exceeded 80%. The regression predictive model provides a reference tool for the visual field design of tractor displays and cab layouts. [ABSTRACT FROM AUTHOR]

This study investigated the effect and long-term efficacy of binocular visual function training after concomitant exotropia surgery. A total of 92 patients who underwent concomitant exotropia surgery were randomly divided into group A (the training group) (n = 54), who received binocular four-dimensional (4D) visual function training after surgery, and group B (control group) (n = 38). The patients in group A received personalized 4D visual function training 2 weeks after surgery and were followed up for 12 months. The eye position, distant and near stereo acuity, respectively, and postoperative efficacy were compared with those of the patients in group B. The normal eye position rate in group A was higher than in group B at the end of the overall follow-up period (p <.05), and the near stereo acuity rate was higher than the distant stereo acuity rate in both groups A and B at 2 weeks after surgery and at the end of follow up. The distant and near stereo acuity rates of the patients in group A were higher than those in group B (p <.05) at the end of the follow-up period, and the distant stereo acuity of group A was significantly improved (p <.05). The functional complete and incomplete response rates of group A were significantly higher than those of group B at the end of the follow-up period (p <.05). Four-dimensional visual function training for patients after concomitant exotropia surgery could facilitate the recovery of postoperative binocular visual function, as well as prevent the recurrence of exotropia after surgery. [ABSTRACT FROM AUTHOR]

Smooth pursuit eye movements and saccadic eye movements are vital for precise vision. Therefore, tests for eye movement are important for assessing nervous or muscular diseases. However, objective measurements are not frequently performed due to the need for a polygraph system, electrodes, amplifier, and personal computer for data analysis. To address this, we developed an all-in-one eye-movement-measuring device that simultaneously presents visual stimuli, records eye positions, and examines its feasibility for evaluating eye movements. This device generates stimulus that induces eye movements and records those movements continuously. The horizontal or vertical eye movements of 16 participants were measured at various visual target speeds of 20–100 deg/s. The maximum cross-correlation coefficient (rho max) between the eye and visual target positions was used as an index of eye movement accuracy. A repeated-measures multi-way analysis of variance was performed, with the main effect being that rho max significantly decreased as the visual target speed increased. The average (±standard deviation) rho max values across all velocities were 0.995 ± 0.008 and 0.967 ± 0.062 in the horizontal and vertical directions, respectively, and were significantly higher for horizontal eye movements than for vertical eye movements. Moreover, rho max and saccadic frequency were significantly correlated for the slowest and fastest visual target motions. These suggest that our device enables accurate measurements of eye movements. We believe our new measurement device can be applied clinically for easily and objectively evaluating eye movements. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the effect of virtual reality (VR) technology in children after surgery for concomitant strabismus. Methods: A total of 200 children with concomitant exotropia or concomitant esotropia were randomly divided into a training group and a control group according to the single even number random method (100 cases in each group). Patients in the training group received VR intervention training within 1 week after surgery. Patients in the control group did not receive any training. Results: Six months after the surgery, the orthophoria (the far or near strabismus degree was ≤8Δ) rate was significantly higher in the training group than in the control group (P = 0.001), while the eye position regression rate (compared to the strabismus degree within 1 week after the surgery, the amount of regression >10Δ) was significantly lower in the training group than in the control group (P = 0.001). Six months after the surgery, the number of children with simultaneous vision and remote stereovision was significantly higher in the training group than in the control group (P = 0.017 and 0.002, respectively). The differences in the number of patients with peripheral stereopsis, macular stereopsis, and stereopsis in macular fovea centralis at 1, 3, and 6 months after the surgery between the training and the control groups were not statistically significant (P = 0.916, 0.274, and 0.302, respectively). Conclusion: The intervention of VR technology after strabismus correction effectively improved children's visual function and maintained their eye position.

Objective: The observers use the optic flow to control self-motion. However, the current state of knowledge indicates that it is difficult to understand how optic flow is used by the visual system without a direct measurement of the changes in the flow patterns caused by eye movements during natural behaviour. The purpose of this literature review is to highlight the importance of the integration between optic flow and eye movements for postural control. Methods: A literature review of the electronic papers through July 2022 was independently performed by three investigators. The selection of the studies was made by a search on PubMed, Scopus, and Google Scholar with two groups of selected keywords. We excluded papers performed on subjects with pathologies, children, and the elderly. Results: The results of this literature analysis highlight that eye movements are required to drive visual motion processing and heading perception in both static and dynamic contexts. Conclusion: Although we now know many neural mechanisms that process heading direction from the optic flow field, a consideration of optic flow patterns relative to gaze direction provides more detailed information on how the retinal flow field is used to control body balance. Doi: 10.28991/ESJ-2022-06-06-020 Full Text: PDF

Purpose: This study aimed to investigate the effect of virtual reality (VR) technology in children after surgery for concomitant strabismus. Methods: A total of 200 children with concomitant exotropia or concomitant esotropia were randomly divided into a training group and a control group according to the single even number random method (100 cases in each group). Patients in the training group received VR intervention training within 1 week after surgery. Patients in the control group did not receive any training. Results: Six months after the surgery, the orthophoria (the far or near strabismus degree was ≤8Δ) rate was significantly higher in the training group than in the control group (P = 0.001), while the eye position regression rate (compared to the strabismus degree within 1 week after the surgery, the amount of regression >10Δ) was significantly lower in the training group than in the control group (P = 0.001). Six months after the surgery, the number of children with simultaneous vision and remote stereovision was significantly higher in the training group than in the control group (P = 0.017 and 0.002, respectively). The differences in the number of patients with peripheral stereopsis, macular stereopsis, and stereopsis in macular fovea centralis at 1, 3, and 6 months after the surgery between the training and the control groups were not statistically significant (P = 0.916, 0.274, and 0.302, respectively). Conclusion: The intervention of VR technology after strabismus correction effectively improved children's visual function and maintained their eye position. [ABSTRACT FROM AUTHOR]

Athletes, particularly ball game players, benefit from focusing on fast-moving visual targets. In this study, we hypothesized that athletes, specifically professional basketball players, exhibit more accurate saccadic eye movements compared to non-athletes. To test this hypothesis, we assessed the eye movements of eight female professional basketball players from the Niigata Albirex BB (basketball player group) and compared them to eight sex-matched healthy volunteers from a previous study. Eye movements were measured using the Eye Score device. The visual target moved continuously for 20 s at a speed of 100 degrees/s in regular triangular wave-like movements horizontally. The subjects tracked the visual targets with maximum accuracy. The total amplitudes of evoked eye movements during tracking were 37.96 ± 0.82 for the basketball player group and 27.74 ± 2.55 deg (mean ± SEM) for the non-athlete group, indicating a significant difference. These findings suggest that basketball players may achieve accurate saccades by employing predictive saccades. The saccades of the basketball players were concentrated at the fifth frame (0.17 s after the onset of target motion), exhibiting a more peaked distribution than the normal curve. The results imply that athletes may execute predictive saccades when tracking targets with predictable movements, even outside of actual competition.

Objective To investigate the effect of esketamine for sedation on eye position during pediatric ophthalmic examination. Methods A total of 88 pediatric patients scheduled to ophthalmic examinations were sedated and randomly allocated to esketamine group (group E, n=44) and sevoflurane group (group S, n=44). The primary outcome was intraoperative eye position rated by surgeons and anesthesiologists. Secondary outcomes included intraocular pressure, the rate of respiratory depression and desaturation, the extubation time of nasopharyngeal airway, the time of postanesthesia care unit (PACU) stay and the agitation scores. Results There was no significant difference in the eye position between group E and group S (P >0.05). The intraocular pressure was higher in group E than that in group S (19.1 mmHg vs 14.3 mmHg, 1 mmHg=0.133 kPa, P<0.001). The occurrence of respiratory depression was lower in group E than that in group S (9.1% vs 36.1%，P=0.002), although the incidence of respiratory desaturation and extubation time was not different between the two groups(P >0.05). The time of PACU stay showed a statistical significance between group E and group S (20.5 min vs 17.2 min, P =0.002). But the agitation score in group E was lower than that in group S (1.2 vs 2.3, P <0.001). The occurrence of agitation was lower in group E compared to group S (2.3% vs 31.8%，P<0.001). Conclusions Esketamine could provide satisfied eye position for pediatric ophthalmic examination, and decrease the incidence of side effects. [ABSTRACT FROM AUTHOR]

Smooth pursuit eye movements and saccadic eye movements are vital for precise vision. Therefore, tests for eye movement are important for assessing nervous or muscular diseases. However, objective measurements are not frequently performed due to the need for a polygraph system, electrodes, amplifier, and personal computer for data analysis. To address this, we developed an all-in-one eye-movement-measuring device that simultaneously presents visual stimuli, records eye positions, and examines its feasibility for evaluating eye movements. This device generates stimulus that induces eye movements and records those movements continuously. The horizontal or vertical eye movements of 16 participants were measured at various visual target speeds of 20–100 deg/s. The maximum cross-correlation coefficient (rho max) between the eye and visual target positions was used as an index of eye movement accuracy. A repeated-measures multi-way analysis of variance was performed, with the main effect being that rho max significantly decreased as the visual target speed increased. The average (±standard deviation) rho max values across all velocities were 0.995 ± 0.008 and 0.967 ± 0.062 in the horizontal and vertical directions, respectively, and were significantly higher for horizontal eye movements than for vertical eye movements. Moreover, rho max and saccadic frequency were significantly correlated for the slowest and fastest visual target motions. These suggest that our device enables accurate measurements of eye movements. We believe our new measurement device can be applied clinically for easily and objectively evaluating eye movements.

Neurons in posterior parietal cortex (PPC) encode many aspects of the sensory world (e.g., scene structure), the posture of the body, and plans for action. For a downstream computation, however, only some of these dimensions are relevant; the rest are "nuisance variables" because their influence on neural activity changes with sensory and behavioral context, potentially corrupting the read-out of relevant information. Here we show that a key postural variable for vision (eye position) is represented robustly in male macaque PPC across a range of contexts, although the tuning of single neurons depended strongly on context. Contexts were defined by different stages of a visually guided reaching task, including (1) a visually sparse epoch, (2) a visually rich epoch, (3) a "go" epoch in which the reach was cued, and (4) during the reach itself. Eye position was constant within trials but varied across trials in a 3 × 3 grid spanning 24° × 24°. Using demixed principal component analysis of neural spike-counts, we found that the subspace of the population response encoding eye position is orthogonal to that encoding task context. Accordingly, a context-naive (fixed-parameter) decoder was nevertheless able to estimate eye position reliably across contexts. Errors were small given the sample size (~1.78°) and would likely be even smaller with larger populations. Moreover, they were comparable to that of decoders that were optimized for each context. Our results suggest that population codes in PPC shield encoded signals from crosstalk to support robust sensorimotor transformations across contexts. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate whether information on extraocular muscle proprioception without visual information affects postural control. Methods: Thirty-five healthy young volunteers participated in the study. Postural control outcomes included the center of pressure (CoP) for static standing, the total length of the sway of the CoP (LNG), and the sway area (SA), as well as the mean CoP in the mediolateral and anteroposterior directions. The following five eye-fixing positions were used: eye-up (E-Up), eye-down (E-Down), eye-right (E-Right), eye-left (E-Left), and eye-center (Center eye position). One-way ANOVA and Bonferroni correction was performed for statistical processing. Electrooculograms were recorded to detect eye orientation errors, measured with the eyes closed. Results: The results of this study showed no significant difference between the LNG and SA results when comparing respective eye positions (E-up, E-down, E-right, E-left) relative to E-Center (control). However, the average CoP was shifted to the right at E-Up, E-Down, and E-Left. Conclusion: These findings indicate that postural control may be affected by eye-body coordination depending on the position of the eyes, even without visual information. [ABSTRACT FROM AUTHOR]

PurposeThe purpose of this study was to investigate whether information on extraocular muscle proprioception without visual information affects postural control.MethodsThirty-five healthy young volunteers participated in the study. Postural control outcomes included the center of pressure (CoP) for static standing, the total length of the sway of the CoP (LNG), and the sway area (SA), as well as the mean CoP in the mediolateral and anteroposterior directions. The following five eye-fixing positions were used: eye-up (E-Up), eye-down (E-Down), eye-right (E-Right), eye-left (E-Left), and eye-center (Center eye position). One-way ANOVA and Bonferroni correction was performed for statistical processing. Electrooculograms were recorded to detect eye orientation errors, measured with the eyes closed.ResultsThe results of this study showed no significant difference between the LNG and SA results when comparing respective eye positions (E-up, E-down, E-right, E-left) relative to E-Center (control). However, the average CoP was shifted to the right at E-Up, E-Down, and E-Left.ConclusionThese findings indicate that postural control may be affected by eye-body coordination depending on the position of the eyes, even without visual information.

Background: While right-left hemispheric valence dichotomies have been demosntrated in various lesion stidues, it not entirely known if these dichotomies are portrayed in art. Methods: We examined 192 paintings to learn if there is an association between paintings that portray happy-positive or sad-negative scenes and the agent looking to the right or left side relative to their head's midsagittal plane. Results: There were 38 paintings with a positive valence and 32 with a negative valence in which the eyes were turned rightward or leftward. Of 38 positive valence paintings, 28 had the agent looking rightward, and 10 looking leftward. Of 32 negative valence paintings, 15 had the agent looking rightward and 17 leftward. Discussion: Hemisphere activation is associated with contralateral deviation of the eyes. Whereas the right hemisphere mediates negative emotions allocates spatial attention to both left and right hemispace, the left hemisphere primarily allocates attention to the right. Since the left hemisphere appears to mediate positive emotions and the right hemisphere negative emotions, results from this study are consistent with hemispheric emotional valence attentional hypotheses. However, the relationship between artist knowledge about gaze and the utilization of gaze direction to portray emotional experiences is not known. [ABSTRACT FROM AUTHOR]

A variety of eye tracking studies have demonstrated that young children with ASD gaze at images and movies of social interactions differently than typically developing children. These findings have supported the hypothesis that gaze behavior differences are generated by a weaker preference for social stimuli in ASD children. The hypothesis assumes that gaze differences are not caused by abnormalities in oculomotor function including saccade frequency and kinematics. Previous studies of oculomotor function have mostly been performed with school‐age children, adolescents, and adults using visual search, anti‐saccade, and gap saccade tasks that are less suitable for young pre‐school children. Here, we examined oculomotor function in 144 children (90 with ASD and 54 controls), 1–10‐years‐old, as they watched two animated movies interleaved with the presentation of multiple salient stimuli that elicited saccades‐to‐targets. The results revealed that the number of fixations, fixation duration, number of saccades, saccade duration, saccade accuracy, and saccade latency did not differ significantly across groups. Minor initial differences in saccade peak velocity were not supported by analysis with a linear mixed model. These findings suggest that most children with ASD exhibit similar oculomotor function to that of controls, when performing saccades‐to‐targets or freely viewing child‐friendly movies. This suggests that previously reported gaze abnormalities in children with ASD are not due to underlying oculomotor deficiencies. Lay Summary This study demonstrates that children with ASD perform similar eye movements to those of controls when freely observing movies or making eye movements to targets. Similar results were apparent across groups in the number of eye movements, their accuracy, duration, and other measures that assess eye movement control. These findings are important for interpreting previously reported differences in gaze behavior of children with ASD, which are likely due to atypical social preferences rather than impaired control of eye movements. [ABSTRACT FROM AUTHOR]

Previous eye‐tracking studies have reported that children with autism spectrum disorders (ASD) fixate less on faces in comparison to controls. To properly understand social interactions, however, children must gaze not only at faces but also at actions, gestures, body movements, contextual details, and objects, thereby creating specific gaze patterns when observing specific social interactions. We presented three different movies with social interactions to 111 children (71 with ASD) who watched each of the movies twice. Typically developing children viewed the movies in a remarkably predictable and reproducible manner, exhibiting gaze patterns that were similar to the mean gaze pattern of other controls, with strong correlations across individuals (intersubject correlations) and across movie presentations (intra‐subject correlations). In contrast, children with ASD exhibited significantly more variable/idiosyncratic gaze patterns that differed from the mean gaze pattern of controls and were weakly correlated across individuals and presentations. Most importantly, quantification of gaze idiosyncrasy in individual children enabled separation of ASD and control children with higher sensitivity and specificity than traditional measures such as time gazing at faces. Individual magnitudes of gaze idiosyncrasy were also significantly correlated with ASD severity and cognitive scores and were significantly correlated across movies and movie presentations, demonstrating clinical sensitivity and reliability. These results suggest that gaze idiosyncrasy is a potent behavioral abnormality that characterizes a considerable number of children with ASD and may contribute to their impaired development. Quantification of gaze idiosyncrasy in individual children may aid in assessing symptom severity and their change in response to treatments. Autism Res 2020, 13: 935‐946. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary: Typically, developing children watch movies of social interactions in a reliable and predictable manner, attending faces, gestures, actions, body movements, and objects that are relevant to the social interaction and its narrative. Here, we demonstrate that children with ASD watch such movies with significantly more variable/idiosyncratic gaze patterns that differ across individuals and across movie presentations. We demonstrate that quantifying this gaze variability may aid in identifying children with ASD and in determining the severity of their symptoms. [ABSTRACT FROM AUTHOR]

Introduction: Vestibular evoked myogenic potential is useful test for assessing function of saccule and inferior vestibular nerve. Vestibular evoked myogenic potential Amplitude is proportional to the level of background Electomyography. In the post-auricular muscle, magnitude of the Electomyography is directly related to the position of the eye. Therefore, this study aimed to assess if eye position effect on Vestibular evoked myogenic potential. Materials and Methods: In this cross-sectional study, vestibular evoked myogenic potential was recorded for 30 normal subjects, aged 18 to 30 years old, using 500 Hz-tone bursts (95 dBnHL) in three eye position: (1) eyes in the same direction as head turn, (2) eyes straight ahead, (3) eyes in the opposite direction to head turn in both ears. Results: In both ears, there was significant difference between mean amplitude of all three positions (P < 0.05). In both ears, mean amplitude of Vestibular evoked myogenic potential in eyes in the opposite direction to head turn was smaller and in eyes in the same direction to head turn was larger than the other two positions. In all three positions and in both ears, mean p13 and n23 latencies did not show any significant difference (P > 0.05). Conclusion: Results of this study shows that magnitude of the response alters depending on the position of a subject’s eyes during recording vestibular evoked myogenic potential. So controlling eye position during recording test is recommend.

Electrical vestibular neurostimulation may be a viable tool for modulating vestibular afferent input to restore vestibular function following injury or disease. To do this, such stimulators must provide afferent input that can be readily interpreted by the central nervous system to accurately represent head motion to drive reflexive behavior. Since vestibular afferents have different galvanic sensitivity, and different natural sensitivities to head rotational velocity and acceleration, and electrical stimulation produces aphysiological synchronous activation of multiple afferents, it is difficult to assign a priori an appropriate transformation between head velocity and acceleration and the properties of the electrical stimulus used to drive vestibular reflex function, i.e., biphasic pulse rate or pulse current amplitude. In order to empirically explore the nature of the transformation between vestibular prosthetic stimulation and vestibular reflex behavior, in Rhesus macaque monkeys we parametrically varied the pulse rate and current amplitude of constant rate and current amplitude pulse trains, and the modulation frequency of sinusoidally modulated pulse trains that were pulse frequency modulated (FM) or current amplitude modulated (AM). In addition, we examined the effects of differential eye position and head position on the observed eye movement responses. We conclude that there is a strong and idiosyncratic, from canal to canal, effect of modulation frequency on the observed eye velocities that are elicited by stimulation. In addition, there is a strong effect of initial eye position and initial head position on the observed responses. These are superimposed on the relationships between pulse frequency or current amplitude and eye velocity that have been shown previously.

Background: Patients with Parkinson’s disease (PD) commonly show spatially asymmetric behaviors, such as veering while attempting to walk in a straight line. While there is general agreement that the lateral motor dysfunction contributes to asymmetric behaviors in PD, it is dispute regarding whether the spatial perception is also biased. In addition, it is not clear whether PD impairs the speed of spatial information process, i.e., the efficiency of information process.Objectives: To assess the visuospatial representation and efficiency of spatial information processing in hemi-PD.Methods: Two saccadic tasks were employed: non-spatial cue evoked saccade and spatial cue evoked saccade. In the former task, an identical visual stimulus (appeared on the body mid-sagittal plane) was artificially associated with a fixed saccadic target (left or right) in a given session. In the latter task, subjects were instructed to make a rightward or leftward saccade based on the perceived location of a visual cue (left vs. right side of the body mid-sagittal plane). We estimated the location of subjective straight ahead (SSA) for each subject by using a psychometric fitting function to fit the location judgment results, enabling evaluation of the symmetry of representation between the left and right hemifields. In addition, since the locations of saccadic targets were same in these two tasks, thus, for each individual subject, the elongated saccadic reaction time (SRT) in the latter task, comparing with the former one, mainly reflects the time spent on judgment of the spatial location of visual cue, i.e., spatial perception. We also assessed the efficiency of spatial perception between two hemispheres, through comparing the normalized SRT (i.e., SRT difference between two tasks) between trials with leftward and rightward judgments.Results: Compared with healthy control subjects (HCs), the SSA was shifted to the contralesional side in both left onset PD (LPD, lesion of right substantia nigra) and right onset PD (RPD, lesion of left substantia nigra) patients. The process of spatial information was significantly longer when a spatial cue appeared in the contralesional hemifield.Conclusions: Patients with hemi-PD showed biased visuospatial representation between left and right hemifields and decreased the efficiency of spatial information processing in the contralesional side. Such results indicate that the hemi-PD impairs both spatial representation and the efficiency of spatial information process, which might contribute to asymmetric behaviors.

Background: Cataract surgery when performed under general anesthesia, especially without neuromuscular blocking agents, eccentric position of the eye has been reported. However, no evidence exists for the need and optimal dose of neuromuscular blocking agents for surgical reasons when the anesthetic management may be done without its need. We hypothesize that the minimal dose atracurium may accomplish the surgical requirement of cataract surgery in children. Materials and Methods: After ethical committee approval, this double-blind, prospective, randomized study was conducted in children scheduled for cataract surgery under general anesthesia. Anesthesia was induced in a standardized manner and using laryngeal mask airway. The patients were randomized into four groups of 55 patients each and atracurium was administered as per group allocation: Group 0: No atracurium was administered; Group 50: Received atracurium at 50% dose of ED 95 ; Group 75: Received atracurium at 75% dose of ED 95 ; Group 100: Received atracurium of 100% dose of ED 95 . Surgeon was asked to grade surgical condition just after the stab incision in the cornea. The primary outcome variable included the need of atracurium supplementation based on grading of surgical conditions by the operating surgeon who was blinded to the randomized group. Results: The need of atracurium due to unacceptable surgical conditions based on surgeon satisfaction score was statistically significant when compared among the groups being maximum in Group 0 (P < 0.001). Also, the surgeon satisfaction score was statistically significant among the groups (P < 0.0001) with the least satisfaction in Group 0. The laryngeal mask airway (LMA) insertion score was statistically significant in the four groups (P - 0.001). However, number of attempts for LMA placement was comparable among the four groups (P - 0.766). Conclusion: We conclude that a balanced anesthetic technique including atracurium provided better surgical condition for cataract procedures in children. The surgical condition improved with increasing dose of atracurium from 25% to 100% ED 95 dose.

Electrical vestibular neurostimulation may be a viable tool for modulating vestibular afferent input to restore vestibular function following injury or disease. To do this, such stimulators must provide afferent input that can be readily interpreted by the central nervous system to accurately represent head motion to drive reflexive behavior. Since vestibular afferents have different galvanic sensitivity, and different natural sensitivities to head rotational velocity and acceleration, and electrical stimulation produces aphysiological synchronous activation of multiple afferents, it is difficult to assign a priori an appropriate transformation between head velocity and acceleration and the properties of the electrical stimulus used to drive vestibular reflex function, i.e., biphasic pulse rate or pulse current amplitude. In order to empirically explore the nature of the transformation between vestibular prosthetic stimulation and vestibular reflex behavior, in Rhesus macaque monkeys we parametrically varied the pulse rate and current amplitude of constant rate and current amplitude pulse trains, and the modulation frequency of sinusoidally modulated pulse trains that were pulse frequency modulated (FM) or current amplitudemodulated (AM). In addition, we examined the effects of differential eye position and head position on the observed eye movement responses. We conclude that there is a strong and idiosyncratic, from canal to canal, effect of modulation frequency on the observed eye velocities that are elicited by stimulation. In addition, there is a strong effect of initial eye position and initial head position on the observed responses. These are superimposed on the relationships between pulse frequency or current amplitude and eye velocity that have been shown previously. [ABSTRACT FROM AUTHOR]

Microsaccades are systematically modulated by peripheral spatial cues, and these eye movements have been implicated in perceptual and motor performance changes in cueing tasks. However, an additional oculomotor factor that may also influence performance in these tasks, fixational eye position itself, has been largely neglected so far. Using precise eye tracking and real-time retinal-image stabilization, we carefully analyzed fixational eye position dynamics and related them to microsaccade generation during spatial cueing. As expected, during baseline fixation, microsaccades corrected for a foveal motor error away from the preferred retinal locus of fixation (the so-called ocular position "set point" of the oculomotor system). However, we found that this relationship was violated during a short period immediately after cue onset; a subset of cue-directed "express microsaccades" that were highly precise in time and direction, and that were larger than regular microsaccades, occurred. These movements, having -100-ms latencies from cue onset, were triggered when fixational eye position was already at the oculomotor set point when the cue appeared; they were thus error-increasing rather than error-decreasing. Critically, even when no microsaccades occurred, fixational eye position itself was systematically deviated toward the cue, again with ~100-ms latency, suggesting that the oculomotor system establishes a new set point at different postcue times. This new set point later switched to being away from the cue after ~200-300 ms. Because eye position alters the location of retinal images, our results suggest that both eye position and microsaccades can be associated with performance changes in spatial cueing tasks. [ABSTRACT FROM AUTHOR]

Background: Patients with Parkinson's disease (PD) commonly show spatially asymmetric behaviors, such as veering while attempting to walk in a straight line. While there is general agreement that the lateral motor dysfunction contributes to asymmetric behaviors in PD, it is dispute regarding whether the spatial perception is also biased. In addition, it is not clear whether PD impairs the speed of spatial information process, i.e., the efficiency of information process. Objectives: To assess the visuospatial representation and efficiency of spatial information processing in hemi-PD. Methods: Two saccadic tasks were employed: non-spatial cue evoked saccade and spatial cue evoked saccade. In the former task, an identical visual stimulus (appeared on the body mid-sagittal plane) was artificially associated with a fixed saccadic target (left or right) in a given session. In the latter task, subjects were instructed to make a rightward or leftward saccade based on the perceived location of a visual cue (left vs. right side of the body mid-sagittal plane).We estimated the location of subjective straight ahead (SSA) for each subject by using a psychometric fitting function to fit the location judgment results, enabling evaluation of the symmetry of representation between the left and right hemifields. In addition, since the locations of saccadic targets were same in these two tasks, thus, for each individual subject, the elongated saccadic reaction time (SRT) in the latter task, comparing with the former one, mainly reflects the time spent on judgment of the spatial location of visual cue, i.e., spatial perception. We also assessed the efficiency of spatial perception between two hemispheres, through comparing the normalized SRT (i.e., SRT difference between two tasks) between trials with leftward and rightward judgments. Results: Compared with healthy control subjects (HCs), the SSA was shifted to the contralesional side in both left onset PD (LPD, lesion of right substantia nigra) and right onset PD (RPD, lesion of left substantia nigra) patients. The process of spatial information was significantly longer when a spatial cue appeared in the contralesional hemifield. Conclusions: Patients with hemi-PD showed biased visuospatial representation between left and right hemifields and decreased the efficiency of spatial information processing in the contralesional side. Such results indicate that the hemi-PD impairs both spatial representation and the efficiency of spatial information process, which might contribute to asymmetric behaviors. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To evaluate the role of neural integrators (NI) in the oculomotor system. Methods: A literature search was carried out using several electronic databases during the months of June 2014 to March 2015. The following keywords were used to generate focused results: ‘neural integrators’, ‘gaze‐holding’, ‘oculomotor integration’, ‘impaired gaze‐holding’, ‘gaze evoked nystagmus’ and ‘gaze dysfunction’. Further materials were found through searching relevant articles within reference lists. Seventy‐one articles were sourced for this review which analysed animal and human subjects and network models; 45 were studies of humans, 16 studies of primates, three studies of felines and one study from rats and network models. The remaining articles were literature reviews. Results: The horizontal and vertical, including torsional, NI are located logically in the brainstem, nearby their appropriate target extraocular motoneuron nuclei for stable eye position in eccentric position. The nucleus prepositus hypoglossi (NPH) and medial vestibular nuclei (MVN) are closely linked at the caudal pons and dorsal rostral medulla, integrating horizontal conjugate eye movement. The interstitial nucleus of Cajal (INC) integrates vertical and torsional eye movement at the upper midbrain. The integrator time constant is averaged to 25 seconds in human horizontal and animal vertical NI to perform its function. Case reports revealed that dysfunction of horizontal NI also resulted in vertical ocular deviations, indicating some overlap of horizontal and vertical gaze control. Furthermore, pharmacological inactivation of NI exposed a population of inhibitory neurotransmitters that permits its mechanism of action; allowing for smooth conjugate movement. Conclusions: Neural integrators operate to integrate eye velocity and eye position information to provide signals to extraocular motoneurons to attain and maintain a new position. Therefore, NI allow image stabilization during horizontal and vertical eye movements at eccentric positions for comfortable single vision. [ABSTRACT FROM AUTHOR]

Categorical bias in location memory in geometric spaces is well established. The present study assessed the presence of the bias in locating eyes in images of human faces. Participants were presented with digital faces and indicated the position of one of the eyes in both upright and inverted orientations. Biases resulted from participants using multiple sources of accessible information. No differences were found for upright vs. inverted face images. Overall, the data were consistent with the retrieval category adjustment model. These distortions may be considered within the forensic context, when eyewitnesses work with a sketch artist or use a computer program to generate an image of the culprit. [ABSTRACT FROM AUTHOR]

Purpose: To compare the amount of esotropia corrected by surgery under general anesthesia and in a conscious state in esotropia surgery.Methods: The charts of 42 patients who underwent surgery under general anesthesia for correction of esotropia were reviewed. Angle of deviation was measured by the alternate prism cover test in awakened state one day before and after surgery. Under general anesthesia, angle of deviation was measured by Hirschberg or Krimsky test in 5 prism diopters (PD) scale 30 minutes after induction and at the end of the surgery. The amount of the angle of esodeviation corrected by surgery measured in awakened state (A-correction) and under general anesthesia (G-correction) was compared and analyzed to identify significant differences.Results: The median age was 4.0 years and the median preoperative esodeviation angle was 30.0 PD. The median amount of G-correction of 30.0 PD was significantly different compared with that of A-correction at postoperative day one (p=0.003). However, differences between A-correction and G-correction were not evident at postoperative one week, one month, and final follow-up examination (p= 0.191, 0.215, and 0.396, respectively).Conclusions: Esotropia in A-correction was comparable to that in G-correction only at postoperative day one. These results suggest that it is desirable to perform esotropia surgery according to the initial surgical plan of awakened state regardless of the divergence of eye position. When in doubt, it could be useful to confirm whether the actual amount of surgical correction under general anesthesia is consistent with the plan and modifying the surgical dose nomogram. [ABSTRACT FROM AUTHOR]

The egocentric reference frame is essential for body orientation and spatial localization of external objects. Recent neuroimaging and lesion studies have revealed that the right hemisphere of humans may play a more dominant role in processing egocentric information than the left hemisphere. However, previous studies of egocentric discrimination mainly focused on assessing the accuracy of egocentric judgment, leaving its timing unexplored. In addition, most previous studies never monitored the subjects' eye position during the experiments, so the influence of eye position on egocentric judgment could not be excluded. In the present study, we systematically assessed the processing of egocentric information in healthy human subjects by measuring the location of their visual subjective straight ahead (SSA) and their manual reaction time (RT) during fixation (monitored by eye tracker). In an egocentric discrimination task, subjects were required to judge the position of a visual cue relative to the subjective mid-sagittal plane and respond as quickly as possible. We found that the SSA of all subjects deviated to the left side of the body mid-sagittal plane. In addition, all subjects but one showed the longest RT at the location closest to the SSA; and in population, the RTs in the left visual field (VF) were longer than that in the right VF. These results might be due to the right hemisphere's dominant role in processing egocentric information, and its more prominent representation of the ipsilateral VF than that of the left hemisphere.

Optic flow is a crucial signal in maintaining postural stability. We sought to investigate whether the activity of postural muscles and body sway was modulated by eye position during the view of radial optic flow stimuli. We manipulated the spatial distribution of dot speed and the fixation point position to simulate specific heading directions combined with different gaze positions. The experiments were performed using stabilometry and surface electromyography (EMG) on 24 right-handed young, healthy volunteers. Center of pressure (COP) signals were analyzed considering antero-posterior and medio-lateral oscillation, COP speed, COP area, and the prevalent direction of oscillation of body sway. We found a significant main effect of body side in all COP parameters, with the right body side showing greater oscillations. The different combinations of optic flow and eye position evoked a non-uniform direction of oscillations in females. The EMG analysis showed a significant main effect for muscle and body side. The results showed that the eye position modulated body sway without changing the activity of principal leg postural muscles, suggesting that the extraretinal input regarding the eye position is a crucial signal that needs to be integrated with perceptual optic flow processing in order to control body sway. [ABSTRACT FROM AUTHOR]

Video eye trackers rely on the position of the pupil centre. However, the pupil centre can shift when the pupil size changes. This pupillary artifact is investigated for binocular vergence accuracy (i.e. fixation disparity) in near vision where the pupil is smaller in the binocular test phase than in the monocular calibration. A regression between recordings of pupil size and fixation disparity allows correcting the pupillary artefact. This corrected fixation disparity appeared to be favourable with respect to reliability and validity, i. e. the correlation of fixation disparity versus heterophoria. The findings provide a quantitative estimation of the pupillary artefact on measured eye position as function of viewing distance and luminance, both for measures of monocular and binocular eye position.

AIM: To study eye position control ability in patients with different types of intermittent strabismus. METHODS: Totally 146 patients with intermittent strabismus treated in our hospital from September 2013 to April 2015 were enrolled in the study. The patients were divided into three groups according to the different types of the patients with intermittent strabismus. Fifty-five patients who had been separated from the strong type were used as part of the strong group,the basic type of 48 cases as the basic group,44 cases of collection insufficiency patients were set up as collection insufficiency group. Visual function and postoperative eye correction of the three groups were analyzed. RESULTS: There were no differences in visual function among the three groups before operation, and the visual function of the three groups were improved after operation, and there was no difference among the three groups(P>0.05).The positive rates were 83.3%,81.2% and 54.6% of the strong group, basic group and collection insufficiency group respectively. There was no difference between the strong group and basic group,(P>0.05).There were significant differences between the strong group, basic group with collection insufficiency group(PCONCLUSION: Operations for intermittent external strabismus is different according to different types. The prognosis of the strong group and basic group is good and the prognosis of collection insufficiency group is poor.

Background and purpose Conjugate eye deviation ( CED) and horizontal skew deviation are often seen in patients with intracerebral hemorrhage ( ICH), but its prognostic significance is unclear. In this study, the association between brain scan assessed eye position and hospital mortality in patients with supratentorial ICH was tested. Methods A retrospective analysis was performed in 316 patients with supratentorial ICH. Eye position was measured on first brain computed tomography or magnetic resonance imaging. Patients with CED, horizontal skew deviation or no deviation were distinguished. The association between eye position and hospital mortality was assessed using logistic regression analysis. Results Conjugate eye deviation was present in 96 (30.4%), skew deviation in 44 (13.9%) and no deviation in 176 (55.7%) patients. In patients with CED, 81.3% had an eye position to the ipsilateral side of the hemorrhage. In univariable regression analysis, skew deviation was associated with mortality (odds ratio 3.10, 95% confidence interval 1.57-6.11; P = 0.001). In multivariable regression analysis, adjusting for age, ICH volume, intraventricular extension and Glasgow Coma Scale, eye position was not independently associated with mortality. Conclusion Horizontal skew eyes were found to be an unfavorable prognostic factor. However, this was not independent of other important predictors of ICH mortality and is most probably explained by its association with worse initial clinical presentation. [ABSTRACT FROM AUTHOR]

Previous research showed that the eyes revisit the location in which the stimulus has been encoded when visual or verbal information is retrieved from memory. A recent study showed that this behavior still occurs 1 week after encoding, suggesting that visual, spatial and linguistic information is tightly associated with the oculomotor trace and stored as an integrated memory representation. However, it is yet unclear whether looking behavior simply remains stable between encoding and recall or whether it changes over time in a more fine-tuned manner. Here, we investigate the time course of looking behavior during recall in multiple sessions across 1 week. Participants encoded visual objects presented in one of the four locations on the computer screen. In five sessions during the week after encoding, they performed on a visual memory recall task. During retrieval, participants looked back to the encoding location, but only in the recall sessions within 1 day of encoding. We discuss different explanations for the temporal dynamics of looking behavior during recall, searching for the role of eye movements in memory. [ABSTRACT FROM AUTHOR]

For a behavioral neuroscientist, fixational eye movements are a double-edged sword. On one edge, they make control of visual stimuli difficult, but on the other edge they provide insight into the ways the visual system acquires information from the environment. We have studied macaque monkeys as models for human visual systems. Fixational eye movements of monkeys are similar to those of humans but they are more often vertically biased and spatially more dispersed. Eye movements scatter stimuli from their intended retinal locations, increase variability of neuronal responses, inflate estimates of receptive field size, and decrease measures of response amplitude. They also bias against successful stimulation of extremely selective cells. Compensating for eye movements reduced these errors and revealed a fine-grained motion pathway from V1 feeding the cortical ventral stream. Compensation is a useful tool for the experimenter, but rather than compensating for eye movements, the brain utilizes them as part of its input. The saccades and drifts that occur during fixation selectively activate different types of V1 neurons. Cells that prefer slower speeds respond during the drift periods with maintained discharges and tend to have smaller receptive fields that are selective for sign of contrast. They are well suited to code small details of the image and to enable our fine detailed vision. Cells that prefer higher speeds fire transient bursts of spikes when the receptive field leaves, crosses, or lands on a stimulus, but only the most transient ones (about one-third of our sample) failed to respond during drifts. Voluntary and fixational saccades had very similar effects, including the presence of a biphasic extraretinal modulation that interacted with stimulus-driven responses. Saccades evoke synchronous bursts that can enhance visibility but these bursts may also participate in the visual masking that contributes to saccadic suppression. Study of the small eye movements of fixation may illuminate some of the big problems in vision. [ABSTRACT FROM AUTHOR]