Experience-dependent visual cue integration based on consistencies between visual and haptic percepts

We study the hypothesis that observers can use haptic percepts as a standard against which the relative reliabilities of visual cues can be judged, and that these reliabilities determine how observers combine depth information provided by these cues. Using a novel visuo-haptic virtual reality environment, subjects viewed and grasped virtual objects. In Experiment 1, subjects were trained under motion relevant conditions, during which haptic and visual motion cues were consistent whereas haptic and visual texture cues were uncorrelated, and texture relevant conditions, during which haptic and texture cues were consistent whereas haptic and motion cues were uncorrelated. Subjects relied more on the motion cue after motion relevant training than after texture relevant training, and more on the texture cue after texture relevant training than after motion relevant training. Experiment 2 studied whether or not subjects could adapt their visual cue combination strategies in a context-dependent manner based on context-dependent consistencies between haptic and visual cues. Subjects successfully learned two cue combination strategies in parallel, and correctly applied each strategy in its appropriate context. Experiment 3, which was similar to Experiment 1 except that it used a more naturalistic experimental task, yielded the same pattern of results as Experiment 1 indicating that the findings do not depend on the precise nature of the experimental task. Overall, the results suggest that observers can involuntarily compare visual and haptic percepts in order to evaluate the relative reliabilities of visual cues, and that these reliabilities determine how cues are combined during three-dimensional visual perception.     

Experience-dependent development of feedforward and feedback circuits between lower and higher areas of mouse visual cortex

Using whole cell recordings, we studied excitatory and inhibitory postsynaptic currents (EPSCs, IPSCs) in feedforward (FF) and feedback (FB) circuits between areas V1 and LM (lateromedial) in developing mouse visual cortex. We found that in mice reared with normal visual experience, FF and FB synapses onto layer 2/3 pyramidal neurons develop equal but submaximal strengths whose EPSCs are increased by monocular lid suture. In contrast, the development and experience-dependence of FF- and FB-IPSCs is pathway-specific. The difference develops during the critical period by strengthening FF-IPSCs, while keeping FB-IPSC amplitudes constant. Monocular lid suture increases FB-IPSCs but does not affect FF-IPSCs.     

Heading and path percepts from visual flow and eye pursuit signals.

The percept of self-motion through the environment is supported by visual motion signals and eye movement signals. The interaction between these signals by decoupling of the eye movement and the pattern of retinal motion during brief simulated ego-movement on straight or circular trajectories was studied. A new response method enabled subjects to report perceived destination and perceived curvature of their future path simultaneously. Various combinations of simulated gaze rotation in the retinal flow and eye pursuit were investigated. Simulated gaze rotation ranged from consistent and larger than, to opponent and larger than eye pursuit. It was found that the perceived destination shifts non-linearly with the mismatch between simulated gaze rotation and eye pursuit. The non-linearity is also revealed in the perceived tangent heading direction and perceived path curvature, although to different extent in different subjects. For the same retinal flow, eye pursuit that is consistent with the simulated gaze rotation reduces heading error and the perceived path straightens out. In contrast, perceived path and/or heading do not become more curved or more biased in the direction opposite to pursuit when the eye -in-head rotation is opposite to the simulated gaze rotation. These observations point to modulation of the effect of the extra-retinal pursuit signal by the visual evidence for eye rotation. In a second experiment, one presented to a stationary eye the sum of a component of simulated gaze rotation and radial flow. It was found that the bi-circular flow component, that characterizes the change in pattern of flow directions by the gaze rotation, induces a shift of perceived heading without appreciable perceived path curvature. Conversely, the complementary component of simulated gaze rotation (bi-radial flow) evokes a percept of motion on a curved path with a small tangent heading error. It was suggested that bi-circular and bi-radial flow components contribute primarily to percepts of heading and path curvature, respectively.     

Classification of apparent motion percepts based on temporal factors

As pointed out by M. Wertheimer (1912), a number of qualitatively different motion impressions, such as "optimal motion," "part motion," and "pure phi," may be evoked by manipulating the temporal parameters of two-element apparent motion sequences. We investigated how the transitions between the different percepts depend on temporal variables over a large range of interstimulus intervals and stimulus onset asynchronies. On the basis of these data, we present a hierarchical classification scheme describing the critical temporal conditions for alternative percepts. A particularly interesting finding is that the distinction between pure phi, on the one hand, and part and optimal motion, on the other, depends on the temporal duty cycle of the stimulus elements. It is suggested that this temporal variable may be used as a cue to resolve occlusion-related ambiguities in classical motion stimuli.     

Characteristics of discrepancies between self-reported visual function and measured reading speed. Salisbury Eye Evaluation Project Team

PURPOSE: Visual impairment is a risk factor for morbidity in the elderly and is often screened for by self-report. This study evaluates whether there are subsets for whom there is a discrepancy between self-reported and measured function. METHODS: The prevalence of a discrepancy between self-reported difficulty reading a newspaper and measured reading speed was determined in 2520 community-based men and women, aged 65 to 84 years, and the discrepant group characterized by polychotomous regression. RESULTS: Of subjects who reported minimal difficulty reading a newspaper, 10.8% (227/2107) read newsprint-sized text (0.21 degrees) more slowly than 80 words/min, a level previously shown to be necessary for sustained reading. Poor visual acuity, presence of psychiatric symptoms, and less satisfaction with vision were associated with being in the group that read slowly and reported difficulty with reading. Better cognition, better visual acuity, more years of education, white race, and fewer psychiatric symptoms were associated with being in the group that read more quickly and reported minimal difficulty. When reading the text size at which subjects read their fastest, only 2.6% of those with minimal difficulty remained discrepant. These individuals were more likely to have less education, be male, be African American, and have poorer cognitive status than those who did not remain discrepant. CONCLUSIONS: A subset of the elderly population have a substantial discrepancy between self-reported reading difficulty and measured reading speed. In some, this discrepancy may be based on underlying expectations and experiences, and in others it may represent a transition from no visual impairment to visual impairment.     

Predicting visual fixations on video based on low-level visual features

To what extent can a computational model of the bottom-up visual attention predict what an observer is looking at? What is the contribution of the low-level visual features in the attention deployment? To answer these questions, a new spatio-temporal computational model is proposed. This model incorporates several visual features; therefore, a fusion algorithm is required to combine the different saliency maps (achromatic, chromatic and temporal). To quantitatively assess the model performances, eye movements were recorded while naive observers viewed natural dynamic scenes. Four completing metrics have been used. In addition, predictions from the proposed model are compared to the predictions from a state of the art model [Itti's model (Itti, L., Koch, C., & Niebur, E. (1998). A model of saliency-based visual attention for rapid scene analysis. IEEE Transactions on Pattern Analysis and Machine Intelligence 20(11), 1254-1259)] and from three non-biologically plausible models (uniform, flicker and centered models). Regardless of the metric used, the proposed model shows significant improvement over the selected benchmarking models (except the centered model). Conclusions are drawn regarding both the influence of low-level visual features over time and the central bias in an eye tracking experiment.     

Relationship between peripapillary vessel density and visual function based on Garway-Heath sectorization in open-angle glaucoma

Purpose:To investigate the relationship between peripapillary vessel density (pVD) and visual field sensitivity (VFS) and between peripapillary retinal nerve fiber layer thickness (pRNFLT) and VFS, based on Garway-Heath sectorization in open-angle glaucoma patients.Methods:Sixty-six eyes of healthy subjects and 84 eyes of glaucoma subjects were included. All subjects underwent several eye examinations, including standard automated perimetry and optical coherence tomography angiography. Sectoral structure-function relationships based on the Garway-Heath sectorization were compared among normal subjects, the ‘mild glaucoma,’ and ‘moderate-to-severe glaucoma’ group. Multivariate analyses were performed for each sector to determine the factors related to VFS. The diagnostic abilities of vessel density parameters and RNFLT were evaluated by calculating the area under the receiver operating characteristic curves (AUROC).Results:The correlation between pVD-VFS and pRNFLT-VFS was statistically significant in the glaucoma group independent of the VFS sector. In the glaucoma group, VFS in the temportal sector was statistically related in a multivariate model to pVD, pRNFLT and age (R² = 0.721; P = 0.007, < 0.001, .15, respectively). We found pRNFLT and age were significantly associated with VFS in glaucoma. The AUROC values of pVD in the inferotemporal sector of the total, mild, and moderate-to-severe glaucoma (0.843, 0.714, and 0.972, respectively) were comparable to pRNFLT in this sector (0.833, 0.718, 0.948, respectively).Conclusion:Since the relationship between pVD and VFS in the papillomacular area was significant, measuring pVD and RNFLT in the corresponding area will be valuable in expanding our pathophysiologic knowledge of the paracentral field defects in glaucoma.     

Correlations between intraocular pressure,visual field and visual acuity,based on 11 years of observations of treated chronic glaucomas

In a retrospective study of 114 patients under treatment for chronic glaucoma (81 without and 33 with visual field defect) over an 11-year period of observation, a highly significant correlation between intraocular pressure and progression of visual field defects could be demonstrated. This correlation could be shown for the visual field outer boundary in 81 eyes with ocular hypertension and for typical visual field defects in 33 eyes with chronic glaucoma. The relationship was, however, only significant when both the standard deviation of the annual intraocular pressure and the influence of cataract development upon visual acuity were considered. Quantitative analysis of the results of Goldmann perimetry was by planimetry and took into account only changes during the 11-year observation period.     

The effects of dichoptic and binocular viewing on bistable motion percepts

Two competitive percepts are produced from a bistable stroboscopic motion display. In this display two frames, each containing three horizontally arrayed elements are presented alternately for several cycles. At short interstimulus intervals (ISIs) element or end-to-end motion responses are obtained when the two inner, spatially overlapping elements are seen as stationary and the third element moves back and forth from one end to the other end. Group motion responses are obtained at longer ISIs when the three elements are seen to move back and forth as a group. The dominance of these two percepts across ISIs was controlled by the manipulation of (1) element size, (2) frame duration, and (3) viewing conditions. Under both binocular and dichoptic viewing, element motion responses increase as element size and frame duration decrease. By maximizing pattern persistence substantial element motion responses were obtained dichoptically as well as binocularly. Instead of supporting the existence of two separate, low-level and high-level, motion systems, our data suggest that there is a single, high-level mechanism for motion whose output can be modulated by pattern persistence.     

Postoperative astigmatic outcomes based on the haptic axis of intraocular lenses inserted in cataract surgery

Purpose

This study was conducted to compare post-operative astigmatic outcomes of two groups, with-the-rule (WTR) and against-the-rule (ATR) astigmatism patients, according to the haptic axis of intraocular lenses (IOLs) inserted in cataract surgery.

Methods

Seventy-two eyes with WTR astigmatism and 79 eyes with ATR astigmatism had cataract surgery through a clear corneal temporal incision. These two groups of eyes were then each divided into 2 groups based on whether the haptic axis of the inserted IOL was at 180° or 90°. For ATR patients, the outcomes were analyzed according to the three types of IOLs.

Results

There was no difference in corneal astigmatism, but WTR patients with a 180° haptic axis of the inserted IOL and ATR patients with a 90° hepatic axis of the inserted IOL had a significant decrease in postoperative refractive astigmatism (p < 0.05). The changes in ATR astigmatism according to the IOL type were more effective in single-piece acrylic IOLs than in the three-piece polymethylmethacrylate haptic IOL group.

Conclusions

Insertion of the IOL at the 180° haptic axis in WTR patients and at 90° in ATR patients during cataract surgery may have an effect in reducing pre-existing astigmatism. This observed effect was not consistent among the different types of IOLs.     

Object co-occurrence serves as a contextual cue to guide and facilitate visual search in a natural viewing environment

There is accumulating evidence that scene context can guide and facilitate visual search (e.g., A. Torralba, A. Oliva, M. S. Castelhano, & J. M. Henderson, 2006). Previous studies utilized stimuli of restricted size, a fixed head position, and context defined by the global spatial configuration of the scene. Thus, it is unknown whether similar effects generalize to natural viewing environments and to context defined by local object co-occurrence. Here, with a mobile eye tracker, we investigated the effects of object co-occurrence on search performance under naturalistic conditions. Observers searched for low-visibility target objects on tables cluttered with everyday objects. Targets were either located adjacent to larger, more visible "cue" objects that they regularly co-occurred in natural scenes (expected condition) or elsewhere in the display, surrounded by unrelated objects (unexpected condition). Mean search times were shorter for targets at expected locations as compared to unexpected locations. Additionally, context guided eye movements, as more fixations were directed toward cue objects than other non-target objects, particularly when the cue was contextually relevant to the current search target. These results could not be accounted for by image saliency models. Thus, we conclude that object co-occurrence can serve as a contextual cue to facilitate search and guide eye movements in natural environments.     

Correlation between visual function and visual ability in patients with uveitis

AIM: To investigate the correlation between tests of visual function and perceived visual ability recorded with a quality of life questionnaire for patients with uveitis. METHODS: 132 patients with various types of uveitis were studied. High (monocular and binocular) and low (binocular) contrast logMAR letter acuities were recorded using a Bailey-Lovie chart. Contrast sensitivity (binocular) was determined using a Pelli-Robson chart. Vision related quality of life was assessed using the Vision Specific Quality of Life (VQOL) questionnaire. RESULTS: VQOL declined with reduced performance on the following tests: binocular high contrast visual acuity (p = 0.0011), high contrast visual acuity of the better eye (p = 0.0012), contrast sensitivity (p = 0.005), binocular low contrast visual acuity (p = 0.0065), and high contrast visual acuity of the worse eye (p = 0.015). Stepwise multiple regression analysis revealed binocular high contrast visual acuity (p <0.01) to be the only visual function adequate to predict VQOL. The age of the patient was also significantly associated with perceived visual ability (p <0.001). CONCLUSIONS: Binocular high contrast visual acuity is a good measure of how uveitis patients perform in real life situations. Vision quality of life is worst in younger patients with poor binocular visual acuity.     

基于云服务技术的视知觉训练与传统综合训练对改善弱视患儿视力和立体视功能的疗效比较

背景 弱视是一种常见的空间视觉发育障碍,可引起单眼及双眼视功能缺陷,传统的治疗仅能改善单眼视力,关于双眼视功能立体视觉的训练研究仍然较少. 目的 评价基于云服务技术的视知觉训练在弱视治疗中的作用,同时与传统的弱视训练方法进行比较,探讨治疗弱视的新方法.方法 采用随机对照临床研究设计,纳入2013年7月至2014年3月在安徽医科大学第二附属医院眼科就诊的弱视患儿107例178眼,按照随机数字表法将患儿随机分为视知觉训练组和传统综合训练组.视知觉训练组采用基于云服务技术的视知觉训练方法,在计算机终端登录该系统,患儿配戴矫正眼镜完成每日训练任务,30 d为1个疗程.每个疗程结束后根据患儿视力及视功能情况以及云服务器中的训练反馈数据调整下一个疗程训练方案,共实施5～6个疗程,训练时遮盖优势眼.传统综合训练组按照同样的训练周期给予健眼遮盖和弱视眼精细目力训练.分别于训练后1个月、3个月进行复查,比较2个组视力和立体视锐度的改善情况. 结果 基于云服务技术的视知觉训练组患儿的视力改善总有效率明显高于传统综合训练组,差异有统计学意义(Z=6.368,P=0.012).视知觉训练组和传统综合训练组患儿训练后平均立体视锐度分别为(127±53)"和(174±67)",均较训练前的(273±95)"和(311±103)"明显改善,且视知觉训练组的立体视锐度变化幅度明显高于传统综合训练组,差异均有统计学意义(t=12.329、9.557、15.649,均P＜0.05).不同程度弱视患儿训练后立体视锐度均较训练前明显提高,重度及中度弱视患儿的立体视锐度改善幅度大于轻度弱视患儿,差异均有统计学意义(均P＜0.05).屈光不正型弱视患儿训练后立体视锐度改善幅度明显高于屈光参差型弱视,差异均有统计学意义(均P＜0.05).结论 基于云服务技术的视知觉训练及传统健眼遮盖联合弱视眼精细训练均可改善弱视患儿的视力和立体视锐度,但基于云服务技术的视知觉训练方法能提高患儿治疗的依从性,适用于弱视患儿的临床治疗,尤其是对传统疗法依从性较差的患儿是一种较好的选择.     

基于CiteSpace的间歇性外斜视的文献计量学及可视化分析

目的：通过文献计量学方法分析间歇性外斜视的研究现状和未来发展趋势。

方法：检索2003-2022年Web of Science数据库核心合集中收录的文献计量学相关文献,运用文献计量学方法,使用CiteSpace6.2.R2软件对年发文量、国家、机构、杂志、作者、参考文献和关键词进行可视化分析。

结果：2003-2022年共检索到620篇间歇性外斜视相关文献,年发文量呈稳定增加的趋势。韩国和美国为发文量最多的国家,最具有生产力的机构为梅奥诊所。发文量最多的作者为Holmes JM。刊文量最多的期刊是The Journal of American Association for Pediatric Ophthalmology and Strabismus(J AAPOS)(共计78篇文献)。关键词和突现词分析可总结出目前该领域的研究热点为间歇性外斜视的手术治疗、流行病学、正位、复发。

结论：应用CiteSpace软件进行可视化分析,可客观反映出2003-2022年间歇性外斜视文献数量变化及分布情况,间歇性外斜视的研究热点已从其手术和流行病学逐渐转移到融合和复发等方面。     

灯箱视力表与电脑视力表临床应用对比研究

目的:通过与灯箱视力表的对比研究了解电脑视力表的临床使用价值。方法:选取初三学生63例(126眼)同时用灯箱和电脑视力表进行远用视力检测,对视力检测值进行配对检验。结果:两种视力表检测值的t检验等于1.2671,P>0.20,两种视力表的检测在统计学上无显著性差异。结论:电脑视力表和灯箱视力表在临床上具有相同的应用价值,可以推广和普及。     

The relationship between visual disability and visual field in patients with glaucoma

PURPOSE: To evaluate the relationship between visual disability and the remaining visual field in glaucoma patients. DESIGN: Prospective noncomparative survey. PARTICIPANTS: One hundred forty-seven Japanese patients with glaucoma were examined. METHODS: Using a previously developed questionnaire, we assessed the relationship between visual disability indices and both the visual field examined using program 30-2 of the Humphrey Field Analyzer and visual acuity. MAIN OUTCOME MEASURES: Pearson's correlation coefficients between visual disability indices and the 22 visual field and 2 visual acuity measurements were calculated. Multiple regression analysis with stepwise variable selection identified factors significantly contributing to visual disability. RESULTS: We identified a significant correlation between visual disability and both the visual field and visual acuity measurements collected. Of the factors examined, retinal sensitivity in the lower hemifield within 5 degrees of the fixation and visual acuity in the better eye significantly contributed to all the item and total disability indices (DIs), measurements of the degree of visual disability as evaluated by the questionnaire; visual acuity in the worse eye contributed to two of the seven item DIs, as well as the total DI. The R value for total DI (R = 0.87, P < 0.0001) indicated that approximately 76% of the visual disability could be explained by these factors. CONCLUSIONS: The Japanese glaucoma patients' visual disability is explained primarily by retinal sensitivity in the lower hemifield within 5 degrees of the fixation and visual acuity in the better eye and secondarily by visual acuity in the worse eye.     

正常人周边区与中央区视觉诱发电位的变化规律

目的探讨正常人周边区与中央区图形翻转视觉诱发电位(visualevokedpotential,VEP)的变化规律。方法以图形翻转VEP作为研究工具研究18例正常人30°以外的上方、下方、鼻侧、颞侧4个方向周边区与中央区在Oz导程对比的图形VEP的波形特征。结果正常人的周边VEP在这4个方向上的N75、P100的潜伏期均随空间频率的增大而增大;N75-P100的峰值却有一个最适的空间频率,即N75-P100峰值只在这个最适空间频率下最大;另外周边区VEPN75、P100的潜伏期均较中央区VEPN75、P100的潜伏期明显延长,周边区VEPN57-P100的峰值均较中央区VEPN75-P100的峰值低。结论视网膜不同区域在枕叶投射的部位决定VEP的潜伏期。