Binocular Visual Perception Research Articles

Effects of visual neuroplasticity training on visual perception, visual quality, and macular blood flow in patients with strabismus.

To observe the effects of visual neuroplasticity training on visual perception, visual quality, and macular blood flow in patients with concomitant strabismus postoperatively. In total, 108 patients underwent binocular strabismus correction operation, and some patients underwent neuroplasticity training. All patients underwent clinical ophthalmic examination, including measurement of best-corrected visual acuity, spherical equivalent, axis length, optical coherence tomography angiography, optical quality analysis system, and visual perception examinations. A total of 78 patients received neuroplasticity training for 1 month postoperatively, and 30 patients did not receive training. All patients underwent a visual perception examination preoperatively and at 1 day, 1 week, and 1 month postoperatively. Macular blood flow and visual quality were examined preoperatively and at 1 month postoperatively. Postoperative visual perception was better than preoperative visual perception ( P < 0.05). After neuroplasticity training, the visual perception of the trained subjects was better than that of the untrained subjects ( P < 0.05), and the blood flow in the macular area of the trained patients was lower than that of the untrained subjects ( P < 0.05). The visual quality of the untrained subjects was lower than that of the trained patients ( P < 0.05). Visual inspection system could accurately evaluate binocular visual perception in patients with concomitant strabismus. After surgical alignment of the strabismus patient, training can stimulate and integrate the formation of stereovision in a short period of time, maintain the visual quality of patients after surgery, and provide conditions for the formation of binocular visual signals and binocular stereovision, but in the short term, it will lead to the decrease of macular blood vessel density and perfusion density. However, the long-term effects of training have not been proven.

A preliminary exploration of quantitative models for evaluating binocular visual perception impairments among patients diagnosed with stroke.

The objective of this study is to formulate and implement graded biological models pertaining to binocular visual perception function with the use of computer algorithms. We aim to quantitatively assess the location, severity, and degree of impairment in binocular visual perception among patients who have suffered stroke, thereby providing valuable insights into the repercussions of cerebral tissue damage on the visual system. To overcome the shortcomings of previous instruments used to assess binocular function in terms of stereoscopic effects and the challenges posed by physiological and psychological interference during examinations, this study optimized its approach by integrating polarized stereovision technology with computer graphic modeling techniques. This study employed computer models to assess binocular visual perception function in stroke patients. Computer models refer to psychophysical testing methods used to measure binocular visual perception function, including various assessment tasks such as recognizing inverted letters and assessing stereopsis during high-speed movements. The cross-into-circle test was used as a means to quantify perceptual eye position. Subsequently, the collected data was analyzed to assess the magnitude of impairment in binocular visual perception. The results of the study revealed a spectrum of binocular visual perception impairment among patients diagnosed with stroke, demonstrating discernible variations in the recognition of inverted letters and stereopsis across different movement speeds. Importantly, perceptual eye position measurements offered valuable insights into ocular misalignment. The computational models effectively quantified both the spatial distribution and severity of these identified impairments. Damage to brain tissue resulting from a stroke can give rise to notable impairments in binocular visual perception function. Graded biological models, formulated through computer algorithms, provide a systematic framework for the comprehensive evaluation and quantification of these impairments. The comprehension of the nature and extent of visual impairments observed in patients with stroke establishes a basis for the development of personalized visual perception learning methodologies. Based on such tailored approaches, we aim to facilitate the recovery of impaired visual function, thereby contributing to the broader objective of neural system rehabilitation.

An Inchworm-Snake Inspired Flexible Robotic Manipulator With Multisection SMA Actuators for Object Grasping

Aiming at achieving the object grasping task, an inchworm-snake inspired Flexible Robotic Manipulator (FRM) is presented in this paper. By using both flexible and rigid materials in the robot structure, the FRM has the stability and control accuracy of a rigid robot as well as the compliant behavior of a soft robot. The piecewise-linear driving characteristic of the Shape Memory Alloy (SMA) actuator enables the accurate establishment of the FRM's kinematic model and model-based control method. Deep learning-based eye-in-hand binocular visual perception is designed to obtain the state feedback without relying on external sensors, making it suitable to perform tasks in confined and unstructured environment. A model-based controller with the deformation planning is introduced with the aim of achieving accurate control in object grasping. The experiments demonstrate that the FRM possesses the capability of performing the object grasping with the proposed methods.

Effect of visual perception training on binocular visual function reconstruction in patients after strabismus surgery.

To explore the effect of visual perception learning software training (VPT) on binocular visual function reconstruction in children with intermittent exotropia after strabismus surgery. Ninety children with intermittent exotropia admitted to our hospital from June 2018 to December 2018 were included, and randomly divided into VPT and control groups. Children in the control group received basic binocular vision training, while those in the VPT group received VPT after strabismus surgery. Tertiary visual function, visual perception function, Newcastle Control Score (NCS), and ocular position retraction rate were compared at 3 and 12mo after the surgery. At 3 and 12mo after the surgery, the proportion of simultaneous perception, binocular fusion version and binocular stereo vision in the VPT group was conspicuously higher than that in the control group (P<0.05). After the vision training, the binocular visual perception functions of children in both groups were significantly improved compared with that before training (P<0.05). Interestingly, the grating sharpness, texture perception and texture motion perception in the VPT group were dramatically better than control group (P<0.01). The NCS in the VPT group was significantly lower than that in the control group (P<0.05). The ocular position retraction rate in the VPT group was significantly lower than that in the control group at 12mo (8.89% vs 26.67%, P=0.03). VPT effectively promotes binocular visual function reconstruction in intermittent exotropia children after strabismus surgery and reduces the strabismus severity and ocular position retraction rate.

Study on the postoperative visual function recovery of children with concomitant exotropia based on an augmented reality plasticity model.

This study aimed to investigate the clinical application effect of an augmented reality (AR) plasticity model on the postoperative visual function recovery of children with concomitant exotropia. Between September 2019 and October 2021, 28 patients with concomitant exotropia who visited Shenzhen Children's Hospital (9 male and 19 female) were enrolled in this study. The average age of the patients was 6.4 ± 1.8 years. Postoperative rehabilitation training was conducted using a personalized AR binocular visual perception plasticity model developed based on the patient's examination results. After 1 month, 3 months, and 6 months of training, the patients returned to the hospital for examinations of perceptual eye position, static zero-order stereopsis, dynamic first-order fine stereopsis, and dynamic second-order coarse stereopsis to compare the changes in eye position control and stereovision function. After 6 months of eye position training, the horizontal perception eye position of the 28 patients was significantly lower than that before training. The difference in eye position at the first and third months compared with that before training was not statistically significant (1st month: z = -2.255, p = 0.024 > 0.017; 3rd month: z = -2.277, p = 0.023 > 0.017; 6th month: z = -3.051, p = 0.002 < 0.017). The difference in vertical perceptual eye position after training compared with that before training was not statistically significant (1st month: z = -0.252, p = 0.801 > 0.017; 3rd month: z = -1.189, p = 0.234 > 0.017; 6th month: z = -2.225, p = 0.026 > 0.017). The difference in 0.8-m static zero-order stereopsis before and after training was not statistically significant (1st month: z = -2.111, p = 0.035 > 0.017; 3rd month: z = -1.097, p = 0.273 > 0.017; 6th month: z = -1.653, p = 0.098 > 0.017). The 1.5-m static zero-order stereopsis was improved after 1 month, 3 months, and 6 months of training compared with that before training (1st month: z = -3.134, p = 0.002 < 0.017; 3rd month: z = -2.835, p = 0.005 < 0.017; 6th month: z = -3.096, p = 0.002 < 0.017). Dynamic first-order fine stereopsis and dynamic second-order coarse stereopsis were measured in the 28 patients before and after training. Patients 1 and 18 had no dynamic first-order fine stereopsis before training, but both regained dynamic stereopsis after 1 month, 3 months, and 6 months of training. Patient 16 had no dynamic first-order fine stereopsis or dynamic second-order coarse stereopsis before training, but first-order and second-order stereopsis had been reconstructed after 1 month, 3 months, and 6 months of training. Concomitant exotropia surgery improved the basic problem of eye position at the ocular muscle level, but the patient's perceptual eye position and visual function defects at the brain visual level remained. This might partly explain the poor postoperative clinical effect. The AR plasticity model can improve patients' horizontal perceptual eye position and multi-dimensional stereoscopic function, and its clinical effect warrants further study.

Multifocal contact lens vision simulated with a clinical binocular simulator

PurposeThe purpose of this study is to compare the binocular visual perception of participants wearing multifocal contact lenses and these same lens designs viewed through a temporal multiplexing visual simulator. MethodsVisual performance and perceived visual quality at various distances were obtained in 37 participants wearing soft M−CLs and through the SimVis Gekko programmed with the same lenses. In a pilot study (n = 10) visual performance was measured in terms of LogMAR visual acuity (VA) at far (4 m), intermediate (64 cm) and near (40 cm) distances and through-focus VA (TFVA) curves with the simulated M−CLs. In the follow-up study (n = 27), LogMAR VA at far, intermediate and near distances were measured both with the actual and simulated M−CLs. Perceived visual quality was measured in both studies using the Multifocal Acceptance Score (MAS-2EV), and a Participants Reported Outcomes Vision questionnaire. Differences between the metrics obtained with simulated and actual lenses were obtained. ResultsBoth actual and simulated M−CLs increased depth-of-focus by a similar amount. Mean LogMAR VA differences with actual and simulated M−CLs ranged between 4 and 6 letters (0.08 ± 0.01, 0.12 ± 0.01 and 0.10 ± 0.01, for far, intermediate and near distances, respectively). MAS-2EV average score differences with actual and simulated M−CLs ranged between −1.00 and + 4.25. Average MAS-2EV scores were not correlated significantly with VA. However, MAS-2EV (average and individual scores) were highly correlated to visual quality questionnaire responses (p < 0.005). ConclusionsA simultaneous vision simulator accurately represented vision with M−CLs both VA at various distances and perceived visual quality, as measured in a clinical setting. The MAS-2EV metric accurately captured participant reported outcomes of standard vision questionnaires. The combination of SimVis Gekko and MAS-2EV has the potential to largely reduce chair time in M−CLs fitting.

Real-Time Detection and Spatial Localization of Insulators for UAV Inspection Based on Binocular Stereo Vision

Unmanned aerial vehicles (UAVs) have become important tools for power transmission line inspection. Cameras installed on the platforms can efficiently obtain aerial images containing information about power equipment. However, most of the existing inspection systems cannot perform automatic real-time detection of transmission line components. In this paper, an automatic transmission line inspection system incorporating UAV remote sensing with binocular visual perception technology is developed to accurately detect and locate power equipment in real time. The system consists of a UAV module, embedded industrial computer, binocular visual perception module, and control and observation module. Insulators, which are key components in power transmission lines as well as fault-prone components, are selected as the detection targets. Insulator detection and spatial localization in aerial images with cluttered backgrounds are interesting but challenging tasks for an automatic transmission line inspection system. A two-stage strategy is proposed to achieve precise identification of insulators. First, candidate insulator regions are obtained based on RGB-D saliency detection. Then, the skeleton structure of candidate insulator regions is extracted. We implement a structure search to realize the final accurate detection of insulators. On the basis of insulator detection results, we further propose a real-time object spatial localization method that combines binocular stereo vision and a global positioning system (GPS). The longitude, latitude, and height of insulators are obtained through coordinate conversion based on the UAV’s real-time flight data and equipment parameters. Experiment results in the actual inspection environment (220 kV power transmission line) show that the presented system meets the requirement of robustness and accuracy of insulator detection and spatial localization in practical engineering.

Individualized Visual Reality Training Improves Visual Acuity and Visual Field Defects in Patients with Glaucoma: A Preliminary Study Report.

To explore whether individualized visual training improves the visual acuity and visual field defects of patients with glaucoma. Patients with established primary glaucoma who visited the glaucoma clinic of Beijing Shijitan Hospital, Capital Medical University from January 2018 to April 2018 were recruited. The binocular visual perception examination was performed by using the visual perception examination system, and a personalized training program was developed according to the relevant threshold conditions between the eyes of the patients. The binocular visual perception training session for 20 minutes for two sessions was completed at home by using a virtual reality helmet. The visual function, intraocular pressure, and Octopus visual field were examined, before and at the first month and the third month after training. Seven patients completed the study. None of the seven patients has fine stereopsis, four of them have large stereopsis, and two patients are without large stereopsis. The visual acuity at 3 months after training was significantly improved compared with that before training. The mean defect value after 1 month of training was significantly lower than that before training, and it was further decreased after 3 months. Similarly, the mean sensitivity value was significantly increased in both follow-ups after training. There was no significant difference in loss variance after 1 and 3 months of training when compared with that before training (p > 0.05). Our small prospective observational study indicated that individualized visual perception training can improve the visual function and improve the visual field in patients with glaucoma, and a large sample size study is warranted to further assess the value of this novel treatment.

Models of Monocular and Binocular Visual Perception in Quality Assessment of Stereoscopic Images

Assessing quality of experience (QoE) for three-dimensional (3-D) video is challenging. In this paper, we propose a new full-reference stereoscopic image quality metric, by simulating the behaviors of visual perception with simple and complex receptive field properties and constructing the models of monocular and binocular visual perception. To be more specific, the stereoscopic images are first classified into noncorresponding and corresponding regions. Then, monocular energy responses are generated for the noncorresponding region based on stimuli from different spatial frequencies and orientations, and binocular energy responses are generated for the corresponding region based on stimuli from different spatial frequencies, orientations and disparities, respectively. Finally, gradient similarities between the energy responses of the original and distorted stereoscopic images are measured for noncorresponding and corresponding regions, respectively, and all results are fused to get an overall score. Experiments on three 3-D image quality assessment (IQA) databases demonstrate that in comparison with the most related existing methods, the devised algorithm achieves higher agreement with subjective assessment, making it better suited for the evaluation and optimization of stereoscopic image processing algorithms.

Binocular Responses for No-Reference 3D Image Quality Assessment

Perceptual quality assessment of distorted three-dimensional (3D) images has become a fundamental yet challenging issue in the field of 3D imaging. In this paper, we propose a general-purpose blind/no-reference (NR) 3D image quality assessment (IQA) metric that utilizes the complementary local patterns (the local magnitude pattern and the proposed generalized local directional pattern) of binocular energy response (BER) and binocular rivalry response (BRR). The main technical contribution of this research is that binocular visual perception and local structural distribution are considered for NR 3D-IQA. More specifically, the metric simulates the binocular visual perception using BER and BRR. Subsequently, the local patterns of the binocular responses’ encoding maps are used to form various binocular quality-predictive features, which will change in the presence of distortions. After feature extraction, we use k -nearest neighbors-based machine learning to drive the overall quality score. We tested our proposed metric against two publicly available 3D databases; these tests confirm that the proposed metric's results consistently align with human subjective judgments.

Monocular-binocular feature fidelity induced index for stereoscopic image quality assessment.

Perceptual three-dimensional image quality assessment (3D-IQA) aims to use computational models to measure image quality in a way that is consistent with human visual perception. Unlike previous studies that directly extended the two-dimensional metrics to the three-dimensional (3D) case, the major technical innovation of this paper is to simulate monocular and binocular visual perception and propose a monocular-binocular feature fidelity induced index for 3D-IQA. To be more specific, in the training stage, we train monocular and binocular dictionaries from the training database, so that the latent response properties can be represented as a set of basis vectors. In the quality estimation stage, we compute monocular feature fidelity and binocular feature fidelity indexes based on the estimated sparse coefficient vectors and compute a global energy response similarity index by considering global energy changes. The final quality score is obtained by incorporating them. Experimental results on four 3D-IQA databases demonstrate that in comparison with the most relevant existing methods, the devised algorithm achieves high consistency alignment with subjective assessment.

47.2: Novel Measurement Method of Bright‐Light Contrast Ratio Based on Binocular Vision

AbstractIt is well known that ambient light reduces the contrast ratio. However binocular human perception is often better than expected by monocular measurements. We evaluated this by subjects and adapted the measurement set‐up to binocular vision. Typical mobile displays were examined and we verified the binocular visual perception of small specular light sources.

A binocular perimetry study of the causes and implications of sensory eye dominance

Sensory eye dominance (SED) reflects an imbalance of interocular inhibition in the binocular network. Extending an earlier work ( Ooi & He, 2001) that measured global SED within the central 6°, the current study measured SED locally at 17 locations within the central 8° of the binocular visual field. The eccentricities (radius) chosen for this, “binocular perimetry”, study were 0° (fovea), 2° and 4°. At each eccentricity, eight concentric locations (polar angle: 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°) were tested. The outcome, an SED map, sets up comparison between local SED and other visual functions [monocular contrast threshold, binocular disparity threshold, reaction time to detect depth, the dynamics of binocular rivalry and motor eye dominance]. Our analysis shows that an observer’s SED varies gradually across the binocular visual field both in its sign and magnitude. The strong eye channel revealed in the SED measurement does not always have a lower monocular contrast threshold, and does not need to be the motor dominant eye. There exists significant correlation between SED and binocular disparity threshold, and between SED and the response time to detect depth of a random-dot stereogram. A significant correlation is also found between SED and the eye that predominates when viewing an extended duration binocular rivalry stimulus. While it is difficult to attribute casual factors based on correlation analyses, these observations agree with the notion that an imbalance of interocular inhibition, which is largely revealed as SED, is a significant factor impeding binocular visual perception.

Postural control in children with strabismus: Effect of eye surgery

The purpose of this study was to examine the postural control in children with strabismus before and after eye surgery. Control of posture is a complex multi-sensorial process relying on visual, vestibular and proprioceptive systems. Reduced influence of one of such systems leads to postural adaptation due to a compensation of one of the other systems [3]. Nine children with strabismus (4–8 years old) participated in the study. Ophthalmologic, orthoptic, vestibular and postural tests were done before and twice (2 and 8 weeks) after eye surgery. Postural stability was measured by a platform (TechnoConcept): two components of the optic flux were used for stimulation (contraction and expansion) and two conditions were tested eyes open and eyes closed. The surface area of the center of pressure (CoP), the variance of speed of the CoP and the frequency spectrum of the platform oscillations by fast Fourier transformation were analysed. Before surgery, similar to typically developing children, postural stability was better in the eyes open condition. The frequency analysis revealed that for the low frequency band more energy was spent in the antero-posterior direction compared to the medio-lateral one while the opposite occurred for the middle and the high frequency bands. After surgery, the eye deviation was reduced in all children and their postural stability also improved. However, the energy of the high frequency band in the medio-lateral direction increased significantly. These findings suggest that eye surgery influences somatosensory properties of extra-ocular muscles leading to improvement of postural control and that binocular visual perception could influence the whole body.

Sensory and sensori-motor adaptations in strabismus: Their role in space perception

In comitant strabismus many perceptual adaptive processes take place, which involve perception of space. Suppression of the image of the deviated eye and anomalous retinal correspondence (ARC) are the two main antidiplopic mechanisms. ARC may be present without suppression in small-angle strabismus (up to 10 degrees), supporting an anomalous binocular cooperation in spite of the deviation. Both psychophysical and electrophysiological evidence for anomalous binocular vision in strabismus are provided. Sensori-motor adaptations in strabismus develop as well. They are represented by vergence eye movements which, although not identical to, have similar characteristics as normal fusional vergences. These anomalous fusional eye movements tend to return the eyes to their original deviation when elements are introduced to change the position of the eyes, e.g., prisms or surgery. In conjunction with ARC, these movements serve to maintain binocular visual perception despite the strabismus.

Binocular visual perception in strabismics studied by means of visual evoked responses.

Ten normal subjects and 14 patients with comitant esotropia were examined by means of pattern visual evoked responses (VER) under monocular and binocular viewing conditions. When both eyes were stimulated together a VER summation was noted both in normals and in strabismics with small-angle deviation and anomalous retinal correspondence (ARC). This is considered as an objective proof of binocularity. Patients with large-angle strabismus and/or suppression of the image of the deviated eye did not show summation. The significance of summation and its relationship with binocular vision was analyzed by recording binocular VER in normals in which diplopia was artificially induced and in strabismics who spontaneously exhibited double vision. A simple way for differentiating normals from strabismics by means of VERs is presented, considering that the presence or absence of summation per se does not achieve this result. This method is based on the anteposition in front of the fixing eye of neutral filters of increasing density. Summation disappears in strabismics with much weaker filters than in normals (0.5 versus 1.6 log. unit).