Review: Familiarity to Vision Rehabilitation Process

Directory of Open Access Journals (Sweden)

Nasser Sadegh-Pour

2006-10-01

Full Text Available Considering the numbers of low vision patients who have been visited and treated in eye clinics, sometimes there is no exact treatment to increase their visual acuity. Therefore, the necessity to pay attention to vision rehabilitation for them is strongly felt. The aims of this essay are to define vision rehabilitation and its process in relevant centers (called Low Vision Clinic.The statistic of low vision people is reported and the method of collecting data is described. Standard definition, causes of low vision and related diseases (congenital, heredity, acquired… are explained. In addition, low vision aids and role of test and prescription are discussed. Sometimes ophthalmologists and optometrists can not exactly cure patient to raise their V.A because there is no treatment or drug or ordinary glasses. In these cases the clients should refer to low vision clinic and visit low vision specialist on vision rehabilitation process. After primary evaluation they are tested completely and at the end are prescribed proper low vision aid and also provided with advice in relation to career, education role and training techniques especially in children. At the last part of present dissertation, some examples are provided to show effectiveness of vision rehabilitation and low vision aid among the clients in different countries.

The Impact of Residual Vision in Spatial Skills of Individuals with Visual Impairments

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Papadopoulos, Konstantinos; Koustriava, Eleni; Kartasidou, Lefkothea

2011-01-01

Loss of vision is believed to have a great impact on the acquisition of spatial knowledge. The aims of the present study are to examine the performance of individuals with visual impairments on spatial tasks and the impact of residual vision on processing these tasks. In all, 28 individuals with visual impairments--blindness or low…

Simplification of Visual Rendering in Simulated Prosthetic Vision Facilitates Navigation.

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Vergnieux, Victor; Macé, Marc J-M; Jouffrais, Christophe

2017-09-01

Visual neuroprostheses are still limited and simulated prosthetic vision (SPV) is used to evaluate potential and forthcoming functionality of these implants. SPV has been used to evaluate the minimum requirement on visual neuroprosthetic characteristics to restore various functions such as reading, objects and face recognition, object grasping, etc. Some of these studies focused on obstacle avoidance but only a few investigated orientation or navigation abilities with prosthetic vision. The resolution of current arrays of electrodes is not sufficient to allow navigation tasks without additional processing of the visual input. In this study, we simulated a low resolution array (15 × 18 electrodes, similar to a forthcoming generation of arrays) and evaluated the navigation abilities restored when visual information was processed with various computer vision algorithms to enhance the visual rendering. Three main visual rendering strategies were compared to a control rendering in a wayfinding task within an unknown environment. The control rendering corresponded to a resizing of the original image onto the electrode array size, according to the average brightness of the pixels. In the first rendering strategy, vision distance was limited to 3, 6, or 9 m, respectively. In the second strategy, the rendering was not based on the brightness of the image pixels, but on the distance between the user and the elements in the field of view. In the last rendering strategy, only the edges of the environments were displayed, similar to a wireframe rendering. All the tested renderings, except the 3 m limitation of the viewing distance, improved navigation performance and decreased cognitive load. Interestingly, the distance-based and wireframe renderings also improved the cognitive mapping of the unknown environment. These results show that low resolution implants are usable for wayfinding if specific computer vision algorithms are used to select and display appropriate

Predicting Visual Disability in Glaucoma With Combinations of Vision Measures.

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Lin, Stephanie; Mihailovic, Aleksandra; West, Sheila K; Johnson, Chris A; Friedman, David S; Kong, Xiangrong; Ramulu, Pradeep Y

2018-04-01

We characterized vision in glaucoma using seven visual measures, with the goals of determining the dimensionality of vision, and how many and which visual measures best model activity limitation. We analyzed cross-sectional data from 150 older adults with glaucoma, collecting seven visual measures: integrated visual field (VF) sensitivity, visual acuity, contrast sensitivity (CS), area under the log CS function, color vision, stereoacuity, and visual acuity with noise. Principal component analysis was used to examine the dimensionality of vision. Multivariable regression models using one, two, or three vision tests (and nonvisual predictors) were compared to determine which was best associated with Rasch-analyzed Glaucoma Quality of Life-15 (GQL-15) person measure scores. The participants had a mean age of 70.2 and IVF sensitivity of 26.6 dB, suggesting mild-to-moderate glaucoma. All seven vision measures loaded similarly onto the first principal component (eigenvectors, 0.220-0.442), which explained 56.9% of the variance in vision scores. In models for GQL scores, the maximum adjusted- R 2 values obtained were 0.263, 0.296, and 0.301 when using one, two, and three vision tests in the models, respectively, though several models in each category had similar adjusted- R 2 values. All three of the best-performing models contained CS. Vision in glaucoma is a multidimensional construct that can be described by several variably-correlated vision measures. Measuring more than two vision tests does not substantially improve models for activity limitation. A sufficient description of disability in glaucoma can be obtained using one to two vision tests, especially VF and CS.

Microcomputer-based artificial vision support system for real-time image processing for camera-driven visual prostheses

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Fink, Wolfgang; You, Cindy X.; Tarbell, Mark A.

2010-01-01

It is difficult to predict exactly what blind subjects with camera-driven visual prostheses (e.g., retinal implants) can perceive. Thus, it is prudent to offer them a wide variety of image processing filters and the capability to engage these filters repeatedly in any user-defined order to enhance their visual perception. To attain true portability, we employ a commercial off-the-shelf battery-powered general purpose Linux microprocessor platform to create the microcomputer-based artificial vision support system (μAVS2) for real-time image processing. Truly standalone, μAVS2 is smaller than a deck of playing cards, lightweight, fast, and equipped with USB, RS-232 and Ethernet interfaces. Image processing filters on μAVS2 operate in a user-defined linear sequential-loop fashion, resulting in vastly reduced memory and CPU requirements during execution. μAVS2 imports raw video frames from a USB or IP camera, performs image processing, and issues the processed data over an outbound Internet TCP/IP or RS-232 connection to the visual prosthesis system. Hence, μAVS2 affords users of current and future visual prostheses independent mobility and the capability to customize the visual perception generated. Additionally, μAVS2 can easily be reconfigured for other prosthetic systems. Testing of μAVS2 with actual retinal implant carriers is envisioned in the near future.

Visual Memory for Objects Following Foveal Vision Loss

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Geringswald, Franziska; Herbik, Anne; Hofmüller, Wolfram; Hoffmann, Michael B.; Pollmann, Stefan

2015-01-01

Allocation of visual attention is crucial for encoding items into visual long-term memory. In free vision, attention is closely linked to the center of gaze, raising the question whether foveal vision loss entails suboptimal deployment of attention and subsequent impairment of object encoding. To investigate this question, we examined visual…

Visual impairment secondary to congenital glaucoma in children: visual responses, optical correction and use of low vision AIDS

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Maria Aparecida Onuki Haddad

2009-01-01

Full Text Available INTRODUCTION: Congenital glaucoma is frequently associated with visual impairment due to optic nerve damage, corneal opacities, cataracts and amblyopia. Poor vision in childhood is related to global developmental problems, and referral to vision habilitation/rehabilitation services should be without delay to promote efficient management of the impaired vision. OBJECTIVE: To analyze data concerning visual response, the use of optical correction and prescribed low vision aids in a population of children with congenital glaucoma. METHOD: The authors analyzed data from 100 children with congenital glaucoma to assess best corrected visual acuity, prescribed optical correction and low vision aids. RESULTS: Fifty-five percent of the sample were male, 43% female. The mean age was 6.3 years. Two percent presented normal visual acuity levels, 29% mild visual impairment, 28% moderate visual impairment, 15% severe visual impairment, 11% profound visual impairment, and 15% near blindness. Sixty-eight percent received optical correction for refractive errors. Optical low vision aids were adopted for distance vision in 34% of the patients and for near vision in 6%. A manual monocular telescopic system with 2.8 × magnification was the most frequently prescribed low vision aid for distance, and for near vision a +38 diopter illuminated stand magnifier was most frequently prescribed. DISCUSSION AND CONCLUSION: Careful low vision assessment and the appropriate prescription of optical corrections and low vision aids are mandatory in children with congenital glaucoma, since this will assist their global development, improving efficiency in daily life activities and promoting social and educational inclusion.

Machine vision automated visual inspection theory, practice and applications

CERN Document Server

Beyerer, Jürgen; Frese, Christian

2016-01-01

The book offers a thorough introduction to machine vision. It is organized in two parts. The first part covers the image acquisition, which is the crucial component of most automated visual inspection systems. All important methods are described in great detail and are presented with a reasoned structure. The second part deals with the modeling and processing of image signals and pays particular regard to methods, which are relevant for automated visual inspection.

Educations of Vision - relational strategies in visual culture

DEFF Research Database (Denmark)

Illeris, Helene

2004-01-01

redescriptions? employs poststructuralist and feminist thinking about visual culture in an attempt to explore alternative understandings of visual education. In the final part ?Educations of vision in late modernity? socialization and self creation are proposed as two different, but supplementary, educational......The article is divided into three parts. Through examples from twentieth century Scandinavian visual arts education the first part ?Epistemological inquiries? discusses how the historical and social construction of dominant modern strategies of vision has occurred. The second part ?Experimentalist...... functions which contemporary visual education inspired by epistemological and experimentalist approaches should aim to fulfill....

Understanding human visual processing with Deep Neural Networks

OpenAIRE

Thorat, Sushrut

2016-01-01

This presentation has 2 parts:1. An introduction to the vision processing - neuroscience, and machine vision.2. Discussion of one of the first papers relating Deep Networks to the visual ventral stream. (Khaligh-Razavi, 2014)

Developments in medical image processing and computational vision

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Jorge, Renato

2015-01-01

This book presents novel and advanced topics in Medical Image Processing and Computational Vision in order to solidify knowledge in the related fields and define their key stakeholders. It contains extended versions of selected papers presented in VipIMAGE 2013 – IV International ECCOMAS Thematic Conference on Computational Vision and Medical Image, which took place in Funchal, Madeira, Portugal, 14-16 October 2013.  The twenty-two chapters were written by invited experts of international recognition and address important issues in medical image processing and computational vision, including: 3D vision, 3D visualization, colour quantisation, continuum mechanics, data fusion, data mining, face recognition, GPU parallelisation, image acquisition and reconstruction, image and video analysis, image clustering, image registration, image restoring, image segmentation, machine learning, modelling and simulation, object detection, object recognition, object tracking, optical flow, pattern recognition, pose estimat...

1st International Conference on Computer Vision and Image Processing

CERN Document Server

Kumar, Sanjeev; Roy, Partha; Sen, Debashis

2017-01-01

This edited volume contains technical contributions in the field of computer vision and image processing presented at the First International Conference on Computer Vision and Image Processing (CVIP 2016). The contributions are thematically divided based on their relation to operations at the lower, middle and higher levels of vision systems, and their applications. The technical contributions in the areas of sensors, acquisition, visualization and enhancement are classified as related to low-level operations. They discuss various modern topics – reconfigurable image system architecture, Scheimpflug camera calibration, real-time autofocusing, climate visualization, tone mapping, super-resolution and image resizing. The technical contributions in the areas of segmentation and retrieval are classified as related to mid-level operations. They discuss some state-of-the-art techniques – non-rigid image registration, iterative image partitioning, egocentric object detection and video shot boundary detection. Th...

Students with Low Vision Describe Their Visual Impairments and Visual Functioning

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Guerette, Amy R.; Lewis, Sandra; Mattingly, Cameron

2011-01-01

In the study reported here, the responses to a survey that was designed to determine the knowledge of their visual impairment of 51 students with low vision were analyzed. Although the students described their visual weaknesses and strengths, they had limited knowledge of, and difficulty communicating about, the medical aspects of their…

Vision and visual information processing in cubozoans

DEFF Research Database (Denmark)

Bielecki, Jan

relationship between acuity and light sensitivity. Animals have evolved a wide variety of solutions to this problem such as folded membranes, to have a larger receptive surfaces, and lenses, to focus light onto the receptive membranes. On the neural capacity side, complex eyes demand huge processing network...... animals in a wide range of behaviours. It is intuitive that a complex eye is energetically very costly, not only in components but also in neural involvement. The increasing behavioural demand added pressure on design specifications and eye evolution is considered an optimization of the inverse...... fit their need. Visual neuroethology integrates optics, sensory equipment, neural network and motor output to explain how animals can perform behaviour in response to a specific visual stimulus. In this doctoral thesis, I will elucidate the individual steps in a visual neuroethological pathway...

Vision and laterality: does occlusion disclose a feedback processing advantage for the right hand system?

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Buekers, M J; Helsen, W F

2000-09-01

The main purpose of this study was to examine whether manual asymmetries could be related to the superiority of the left hemisphere/right hand system in processing visual feedback. Subjects were tested when performing single (Experiment 1) and reciprocal (Experiment 2) aiming movements under different vision conditions (full vision, 20 ms on/180 ms off, 10/90, 40/160, 20/80, 60/120, 20/40). Although in both experiments right hand advantages were found, manual asymmetries did not interact with intermittent vision conditions. Similar patterns of results were found across vision conditions for both hands. These data do not support the visual feedback processing hypothesis of manual asymmetry. Motor performance is affected to the same extent for both hand systems when vision is degraded.

Visual Search Performance in Patients with Vision Impairment: A Systematic Review.

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Senger, Cassia; Margarido, Maria Rita Rodrigues Alves; De Moraes, Carlos Gustavo; De Fendi, Ligia Issa; Messias, André; Paula, Jayter Silva

2017-11-01

Patients with visual impairment are constantly facing challenges to achieve an independent and productive life, which depends upon both a good visual discrimination and search capacities. Given that visual search is a critical skill for several daily tasks and could be used as an index of the overall visual function, we investigated the relationship between vision impairment and visual search performance. A comprehensive search was undertaken using electronic PubMed, EMBASE, LILACS, and Cochrane databases from January 1980 to December 2016, applying the following terms: "visual search", "visual search performance", "visual impairment", "visual exploration", "visual field", "hemianopia", "search time", "vision lost", "visual loss", and "low vision". Two hundred seventy six studies from 12,059 electronic database files were selected, and 40 of them were included in this review. Studies included participants of all ages, both sexes, and the sample sizes ranged from 5 to 199 participants. Visual impairment was associated with worse visual search performance in several ophthalmologic conditions, which were either artificially induced, or related to specific eye and neurological diseases. This systematic review details all the described circumstances interfering with visual search tasks, highlights the need for developing technical standards, and outlines patterns for diagnosis and therapy using visual search capabilities.

Impact of low vision rehabilitation on functional vision performance of children with visual impairment

Directory of Open Access Journals (Sweden)

Suma Ganesh

2013-01-01

Conclusions: In our study group, there was a significant improvement in functional vision post visual rehabilitation, especially with those activities which are related to their academic output. It is important for these children to have an early visual rehabilitation to decrease the impairment associated with these decreased visual output and to enhance their learning abilities.

Evolution of attention mechanisms for early visual processing

Science.gov (United States)

Müller, Thomas; Knoll, Alois

2011-03-01

Early visual processing as a method to speed up computations on visual input data has long been discussed in the computer vision community. The general target of a such approaches is to filter nonrelevant information from the costly higher-level visual processing algorithms. By insertion of this additional filter layer the overall approach can be speeded up without actually changing the visual processing methodology. Being inspired by the layered architecture of the human visual processing apparatus, several approaches for early visual processing have been recently proposed. Most promising in this field is the extraction of a saliency map to determine regions of current attention in the visual field. Such saliency can be computed in a bottom-up manner, i.e. the theory claims that static regions of attention emerge from a certain color footprint, and dynamic regions of attention emerge from connected blobs of textures moving in a uniform way in the visual field. Top-down saliency effects are either unconscious through inherent mechanisms like inhibition-of-return, i.e. within a period of time the attention level paid to a certain region automatically decreases if the properties of that region do not change, or volitional through cognitive feedback, e.g. if an object moves consistently in the visual field. These bottom-up and top-down saliency effects have been implemented and evaluated in a previous computer vision system for the project JAST. In this paper an extension applying evolutionary processes is proposed. The prior vision system utilized multiple threads to analyze the regions of attention delivered from the early processing mechanism. Here, in addition, multiple saliency units are used to produce these regions of attention. All of these saliency units have different parameter-sets. The idea is to let the population of saliency units create regions of attention, then evaluate the results with cognitive feedback and finally apply the genetic mechanism

A framework for breast cancer visualization using augmented reality x-ray vision technique in mobile technology

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Rahman, Hameedur; Arshad, Haslina; Mahmud, Rozi; Mahayuddin, Zainal Rasyid

2017-10-01

Breast Cancer patients who require breast biopsy has increased over the past years. Augmented Reality guided core biopsy of breast has become the method of choice for researchers. However, this cancer visualization has limitations to the extent of superimposing the 3D imaging data only. In this paper, we are introducing an Augmented Reality visualization framework that enables breast cancer biopsy image guidance by using X-Ray vision technique on a mobile display. This framework consists of 4 phases where it initially acquires the image from CT/MRI and process the medical images into 3D slices, secondly it will purify these 3D grayscale slices into 3D breast tumor model using 3D modeling reconstruction technique. Further, in visualization processing this virtual 3D breast tumor model has been enhanced using X-ray vision technique to see through the skin of the phantom and the final composition of it is displayed on handheld device to optimize the accuracy of the visualization in six degree of freedom. The framework is perceived as an improved visualization experience because the Augmented Reality x-ray vision allowed direct understanding of the breast tumor beyond the visible surface and direct guidance towards accurate biopsy targets.

Crowded visual search in children with normal vision and children with visual impairment

NARCIS (Netherlands)

Huurneman, Bianca; Cox, Ralf F. A.; Vlaskamp, Björn N. S.; Boonstra, F. Nienke

This study investigates the influence of oculomotor control, crowding, and attentional factors on visual search in children with normal vision ([NV], n = 11), children with visual impairment without nystagmus ([VI-nys], n = 11), and children with VI with accompanying nystagmus ([VI+nys], n = 26).

Processing reafferent and exafferent visual information for action and perception.

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Reichenbach, Alexandra; Diedrichsen, Jörn

2015-01-01

A recent study suggests that reafferent hand-related visual information utilizes a privileged, attention-independent processing channel for motor control. This process was termed visuomotor binding to reflect its proposed function: linking visual reafferences to the corresponding motor control centers. Here, we ask whether the advantage of processing reafferent over exafferent visual information is a specific feature of the motor processing stream or whether the improved processing also benefits the perceptual processing stream. Human participants performed a bimanual reaching task in a cluttered visual display, and one of the visual hand cursors could be displaced laterally during the movement. We measured the rapid feedback responses of the motor system as well as matched perceptual judgments of which cursor was displaced. Perceptual judgments were either made by watching the visual scene without moving or made simultaneously to the reaching tasks, such that the perceptual processing stream could also profit from the specialized processing of reafferent information in the latter case. Our results demonstrate that perceptual judgments in the heavily cluttered visual environment were improved when performed based on reafferent information. Even in this case, however, the filtering capability of the perceptual processing stream suffered more from the increasing complexity of the visual scene than the motor processing stream. These findings suggest partly shared and partly segregated processing of reafferent information for vision for motor control versus vision for perception.

Vision rehabilitation for visual-vestibular dysfunction: the role of the neuro-optometrist.

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Cohen, Allen H

2013-01-01

This article discusses, in a clinically relevant format, the importance of including a neuro-optometrist as a member of the management team for patients with balance disorders. To review the importance of vision and visual processing for maintaining a sense of balance and equilibrium and the role of the neuro-optometrist in the overall rehabilitation of patients with balance disorders Dizziness, balance problems and the sensation that the space world is moving (vertigo) are one of the most commonly reported problems in general medical practice. Persons with a central nervous system injury or other idiopathic causes of visual processing problems or who have functional vision problems that are not adequately managed, often experience extreme difficulty with balance and movement, as well as with their perception of space. Consequently, the patient often experiences difficulty functioning in an environment with excessive visual stimulation such as a grocery store or shopping mall. Symptoms of disequilibrium, vestibular and balance problems are commonly a result of VOR disturbance secondary to an inner ear problem and an unstable binocularity. The combination of neuro-optomertic rehabilitative therapy and balance therapy will result in a is an effective treatment for reducing or resolving these symptoms.

Clinical characteristics and causes of visual impairment in a low vision clinic in northern Jordan

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Bakkar MM

2018-04-01

Full Text Available May M Bakkar, Eman A Alzghoul, Mera F Haddad Faculty of Applied Medical Sciences, Department of Allied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan Aim: The aim of the study was to identify causes of visual impairment among patients attending a low vision clinic in the north of Jordan and to study the relevant demographic characteristics of these patients.Subjects and methods: The retrospective study was conducted through a review of clinical records of 135 patients who attended a low vision clinic in Irbid. Clinical characteristics of the patients were collected, including age, gender, primary cause of low vision, best corrected visual acuity, and current prescribed low vision aids. Descriptive statistics analysis using numbers and percentages were calculated to summarize categorical and nominal data.Results: A total of 135 patients (61 [45.2%] females and 74 [54.8%] males were recruited in the study. Mean age ± standard deviation for the study population was 24.53 ± 16.245 years; age range was 5–90 years. Of the study population, 26 patients (19.3% had mild visual impairment, 61 patients (45.2% had moderate visual impairment, 27 patients (20.0% had severe visual impairment, and 21 patients (15.6% were blind. The leading causes of visual impairment across all age groups were albinism (31.9% and retinitis pigmentosa (RP (18.5%. Albinism also accounted for the leading cause of visual impairment among the pediatric age group (0–15 years while albinism, RP, and keratoconus were the primary causes of visual impairment for older patients. A total of 59 patients (43.7% were given low vision aids either for near or distance. The only prescribed low vision aids for distances were telescopes. For near, spectacle-type low vision aid was the most commonly prescribed low vision aids.Conclusion: Low vision services in Jordan are still very limited. A national strategy programme to increase awareness of low vision

Clinical characteristics and causes of visual impairment in a low vision clinic in northern Jordan.

Science.gov (United States)

Bakkar, May M; Alzghoul, Eman A; Haddad, Mera F

2018-01-01

The aim of the study was to identify causes of visual impairment among patients attending a low vision clinic in the north of Jordan and to study the relevant demographic characteristics of these patients. The retrospective study was conducted through a review of clinical records of 135 patients who attended a low vision clinic in Irbid. Clinical characteristics of the patients were collected, including age, gender, primary cause of low vision, best corrected visual acuity, and current prescribed low vision aids. Descriptive statistics analysis using numbers and percentages were calculated to summarize categorical and nominal data. A total of 135 patients (61 [45.2%] females and 74 [54.8%] males) were recruited in the study. Mean age ± standard deviation for the study population was 24.53 ± 16.245 years; age range was 5-90 years. Of the study population, 26 patients (19.3%) had mild visual impairment, 61 patients (45.2%) had moderate visual impairment, 27 patients (20.0%) had severe visual impairment, and 21 patients (15.6%) were blind. The leading causes of visual impairment across all age groups were albinism (31.9%) and retinitis pigmentosa (RP) (18.5%). Albinism also accounted for the leading cause of visual impairment among the pediatric age group (0-15 years) while albinism, RP, and keratoconus were the primary causes of visual impairment for older patients. A total of 59 patients (43.7%) were given low vision aids either for near or distance. The only prescribed low vision aids for distances were telescopes. For near, spectacle-type low vision aid was the most commonly prescribed low vision aids. Low vision services in Jordan are still very limited. A national strategy programme to increase awareness of low vision services should be implemented, and health care policies should be enforced to cover low vision aids through the national medical insurance.

Creative Organizational Vision Building through Collaborative, Visual-Metaphorical Thought.

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Ambrose, Don

1998-01-01

Describes use of collaborative metaphorical discussions, mind mapping, and imaginative visual thinking by the faculty of the Rider University School of Education to produce an idealistic vision of the college's future. This vision is expressed as a fanciful metaphorical drawing surrounded by a mind map and accompanied by a story connecting symbols…

The visual advice centre Eindhoven, an experiment in Dutch low vision care

NARCIS (Netherlands)

Neve, J.J.; Jorritsma, F.F.; Kinds, G.F.; Kooijman, A.C.; Looijestijn, P.L.; Welling, J.A.; Wildt, van der G.J.

1994-01-01

The Visual Advice Centre Eindhoven (VAC-E) provides the partially sighted with advice and prescriptions for low vision aids and illumination on the basis of an examination of their individual needs and their residual visual abilities. In the Dutch context of low vision care the V AC-E can be

Improvement of visual acuity by refraction in a low-vision population.

Science.gov (United States)

Sunness, Janet S; El Annan, Jaafar

2010-07-01

Refraction often may be overlooked in low-vision patients, because the main cause of vision decrease is not refractive, but rather is the result of underlying ocular disease. This retrospective study was carried out to determine how frequently and to what extent visual acuity is improved by refraction in a low-vision population. Cross-sectional study. Seven hundred thirty-nine low-vision patients seen for the first time. A database with all new low-vision patients seen from November 2005 through June 2008 recorded presenting visual acuity using an Early Treatment Diabetic Retinopathy Study chart; it also recorded the best-corrected visual acuity (BCVA) if it was 2 lines or more better than the presenting visual acuity. Retinoscopy was carried out on all patients, followed by manifest refraction. Improvement in visual acuity. Median presenting acuity was 20/80(-2) (interquartile range, 20/50-20/200). There was an improvement of 2 lines or more of visual acuity in 81 patients (11% of all patients), with 22 patients (3% of all patients) improving by 4 lines or more. There was no significant difference in age or in presenting visual acuity between the group that did not improve by refraction and the group that did improve. When stratified by diagnosis, the only 2 diagnoses with a significantly higher rate of improvement than the age-related macular degeneration group were myopic degeneration and progressive myopia (odds ratio, 4.8; 95% confidence interval [CI], 3.0-6.7) and status post-retinal detachment (odds ratio, 7.1; 95% CI, 5.2-9.0). For 5 patients (6% of those with improvement), the eye that was 1 line or more worse than the fellow eye at presentation became the eye that was 1 line or more better than the fellow eye after refraction. A significant improvement in visual acuity was attained by refraction in 11% of the new low-vision patients. Improvement was seen across diagnoses and the range of presenting visual acuity. The worse-seeing eye at presentation may

The consequence of spatial visual processing dysfunction caused by traumatic brain injury (TBI).

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Padula, William V; Capo-Aponte, Jose E; Padula, William V; Singman, Eric L; Jenness, Jonathan

2017-01-01

A bi-modal visual processing model is supported by research to affect dysfunction following a traumatic brain injury (TBI). TBI causes dysfunction of visual processing affecting binocularity, spatial orientation, posture and balance. Research demonstrates that prescription of prisms influence the plasticity between spatial visual processing and motor-sensory systems improving visual processing and reducing symptoms following a TBI. The rationale demonstrates that visual processing underlies the functional aspects of binocularity, balance and posture. The bi-modal visual process maintains plasticity for efficiency. Compromise causes Post Trauma Vision Syndrome (PTVS) and Visual Midline Shift Syndrome (VMSS). Rehabilitation through use of lenses, prisms and sectoral occlusion has inter-professional implications in rehabilitation affecting the plasticity of the bi-modal visual process, thereby improving binocularity, spatial orientation, posture and balance Main outcomes: This review provides an opportunity to create a new perspective of the consequences of TBI on visual processing and the symptoms that are often caused by trauma. It also serves to provide a perspective of visual processing dysfunction that has potential for developing new approaches of rehabilitation. Understanding vision as a bi-modal process facilitates a new perspective of visual processing and the potentials for rehabilitation following a concussion, brain injury or other neurological events.

Use of an augmented-vision device for visual search by patients with tunnel vision.

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Luo, Gang; Peli, Eli

2006-09-01

To study the effect of an augmented-vision device that superimposes minified contour images over natural vision on visual search performance of patients with tunnel vision. Twelve subjects with tunnel vision searched for targets presented outside their visual fields (VFs) on a blank background under three cue conditions (with contour cues provided by the device, with auditory cues, and without cues). Three subjects (VF, 8 degrees -11 degrees wide) carried out the search over a 90 degrees x 74 degrees area, and nine subjects (VF, 7 degrees -16 degrees wide) carried out the search over a 66 degrees x 52 degrees area. Eye and head movements were recorded for performance analyses that included directness of search path, search time, and gaze speed. Directness of the search path was greatly and significantly improved when the contour or auditory cues were provided in the larger and the smaller area searches. When using the device, a significant reduction in search time (28% approximately 74%) was demonstrated by all three subjects in the larger area search and by subjects with VFs wider than 10 degrees in the smaller area search (average, 22%). Directness and gaze speed accounted for 90% of the variability of search time. Although performance improvement with the device for the larger search area was obvious, whether it was helpful for the smaller search area depended on VF and gaze speed. Because improvement in directness was demonstrated, increased gaze speed, which could result from further training and adaptation to the device, might enable patients with small VFs to benefit from the device for visual search tasks.

How to improve the efficient use of functional vision of people with visual impairment

OpenAIRE

Mohorko, Ana

2013-01-01

Barraga was the first researcher to study the effects of a special program for developing visual efficiency which showed improvements in visual acuity and visual functioning in blind children with remaining vision. Her breakthrough findings helped develop new theories of visual functioning. These theories represent a foundation from which a professional can understand the visual functioning of an individual with low vision. Providing opportunities for individuals to learn how to use their vis...

Auditory and visual reaction time and peripheral field of vision in helmet users

Directory of Open Access Journals (Sweden)

Abbupillai Adhilakshmi

2016-12-01

Full Text Available Background: The incidence of fatal accidents are more in two wheeler drivers compared to four wheeler drivers. Head injury is of serious concern when recovery and prognosis of the patients are warranted, helmets are being used for safety purposes by moped, scooters and motorcycle drivers. Although, helmets are designed with cushioning effect to prevent head injuries but there are evidences of increase risk of neck injuries and reduced peripheral vision and hearing in helmet users. A complete full coverage helmets provide about less than 3 percent restrictions in horizontal peripheral visual field compared to rider without helmet. The standard company patented ergonomically designed helmets which does not affect the peripheral vision neither auditory reaction time. Objective: This pilot study aimed to evaluate the peripheral field of vision and auditory and visual reaction time in a hypertensive, diabetic and healthy male and female in order to have a better insight of protective characteristics of helmet in health and disease. Method: This pilot study carried out on age matched male of one healthy, one hypertensive and one diabetic and female subject of one healthy, one hypertensive and one diabetics. The field of vision was assessed by Lister’s perimeter whereas auditory and visual reaction time was recorded with response analyser. Result : Gender difference was not noted in peripheral field of vision but mild difference was found in auditory reaction time for high frequency and visual reaction time for both red and green colour in healthy control. But lateral and downward peripheral visual field was found reduced whereas auditory and visual reaction time was found increased in both hypertensive and diabetic subject in both sexes. Conclusion: Peripheral vision, auditory reaction time and visual reaction time in hypertensive and diabetics may lead to vulnerable accident. Helmet use has proven to reduce extent of injury in motorcyclist and

Impact of correcting visual impairment and low vision in deaf-mute students in Pune, India.

Science.gov (United States)

Gogate, Parikshit; Bhusan, Shashi; Ray, Shantanu; Shinde, Amit

2016-12-01

The aim of this study was to evaluate visual acuity and vision function before and after providing spectacles and low vision devices (LVDs) in deaf-mute students. Schools for deaf-mute in West Maharashtra. Hearing-impaired children in all special schools in Pune district underwent detailed visual acuity testing (with teachers' help), refraction, external ocular examination, and fundoscopy. Students with refractive errors and low vision were provided with spectacles and LVD. The LV Prasad-Functional Vision Questionnaire consisting of twenty items was administered to each subject before and after providing spectacles, LVDs. Wilcoxon matched-pairs signed-ranks test. 252/929 (27.1%) students had a refractive error. 794 (85.5%) were profound deaf. Two-hundred and fifty students were dispensed spectacles and LVDs. Mean LogMAR visual acuity before introduction of spectacles and LVDs were 0.33 ± 0.36 which improved to 0.058 (P vision pre- and post-intervention was statistically significant (P vision was much worse than their friend's vision, which was reduced to 17.6% after dispensing spectacles and LVDs. Spectacle and LVD reduced visual impairment and improved vision function in deaf-mute students, augmenting their ability to negotiate in and out of school.

Improvements in clinical and functional vision and perceived visual disability after first and second eye cataract surgery

OpenAIRE

Elliott, D.; Patla, A.; Bullimore, M.

1997-01-01

AIMS—To determine the improvements in clinical and functional vision and perceived visual disability after first and second eye cataract surgery.
METHODS—Clinical vision (monocular and binocular high and low contrast visual acuity, contrast sensitivity, and disability glare), functional vision (face identity and expression recognition, reading speed, word acuity, and mobility orientation), and perceived visual disability (Activities of Daily Vision Scale) were measured in 25 subjects before a...

Are Visual Peripheries Forever Young?

Directory of Open Access Journals (Sweden)

Kalina Burnat

2015-01-01

Full Text Available The paper presents a concept of lifelong plasticity of peripheral vision. Central vision processing is accepted as critical and irreplaceable for normal perception in humans. While peripheral processing chiefly carries information about motion stimuli features and redirects foveal attention to new objects, it can also take over functions typical for central vision. Here I review the data showing the plasticity of peripheral vision found in functional, developmental, and comparative studies. Even though it is well established that afferent projections from central and peripheral retinal regions are not established simultaneously during early postnatal life, central vision is commonly used as a general model of development of the visual system. Based on clinical studies and visually deprived animal models, I describe how central and peripheral visual field representations separately rely on early visual experience. Peripheral visual processing (motion is more affected by binocular visual deprivation than central visual processing (spatial resolution. In addition, our own experimental findings show the possible recruitment of coarse peripheral vision for fine spatial analysis. Accordingly, I hypothesize that the balance between central and peripheral visual processing, established in the course of development, is susceptible to plastic adaptations during the entire life span, with peripheral vision capable of taking over central processing.

Are visual peripheries forever young?

Science.gov (United States)

Burnat, Kalina

2015-01-01

The paper presents a concept of lifelong plasticity of peripheral vision. Central vision processing is accepted as critical and irreplaceable for normal perception in humans. While peripheral processing chiefly carries information about motion stimuli features and redirects foveal attention to new objects, it can also take over functions typical for central vision. Here I review the data showing the plasticity of peripheral vision found in functional, developmental, and comparative studies. Even though it is well established that afferent projections from central and peripheral retinal regions are not established simultaneously during early postnatal life, central vision is commonly used as a general model of development of the visual system. Based on clinical studies and visually deprived animal models, I describe how central and peripheral visual field representations separately rely on early visual experience. Peripheral visual processing (motion) is more affected by binocular visual deprivation than central visual processing (spatial resolution). In addition, our own experimental findings show the possible recruitment of coarse peripheral vision for fine spatial analysis. Accordingly, I hypothesize that the balance between central and peripheral visual processing, established in the course of development, is susceptible to plastic adaptations during the entire life span, with peripheral vision capable of taking over central processing.

Smartphones as image processing systems for prosthetic vision.

Science.gov (United States)

Zapf, Marc P; Matteucci, Paul B; Lovell, Nigel H; Suaning, Gregg J

2013-01-01

The feasibility of implants for prosthetic vision has been demonstrated by research and commercial organizations. In most devices, an essential forerunner to the internal stimulation circuit is an external electronics solution for capturing, processing and relaying image information as well as extracting useful features from the scene surrounding the patient. The capabilities and multitude of image processing algorithms that can be performed by the device in real-time plays a major part in the final quality of the prosthetic vision. It is therefore optimal to use powerful hardware yet to avoid bulky, straining solutions. Recent publications have reported of portable single-board computers fast enough for computationally intensive image processing. Following the rapid evolution of commercial, ultra-portable ARM (Advanced RISC machine) mobile devices, the authors investigated the feasibility of modern smartphones running complex face detection as external processing devices for vision implants. The role of dedicated graphics processors in speeding up computation was evaluated while performing a demanding noise reduction algorithm (image denoising). The time required for face detection was found to decrease by 95% from 2.5 year old to recent devices. In denoising, graphics acceleration played a major role, speeding up denoising by a factor of 18. These results demonstrate that the technology has matured sufficiently to be considered as a valid external electronics platform for visual prosthetic research.

3-D vision and figure-ground separation by visual cortex.

Science.gov (United States)

Grossberg, S

1994-01-01

A neural network theory of three-dimensional (3-D) vision, called FACADE theory, is described. The theory proposes a solution of the classical figure-ground problem for biological vision. It does so by suggesting how boundary representations and surface representations are formed within a boundary contour system (BCS) and a feature contour system (FCS). The BCS and FCS interact reciprocally to form 3-D boundary and surface representations that are mutually consistent. Their interactions generate 3-D percepts wherein occluding and occluded object parts are separated, completed, and grouped. The theory clarifies how preattentive processes of 3-D perception and figure-ground separation interact reciprocally with attentive processes of spatial localization, object recognition, and visual search. A new theory of stereopsis is proposed that predicts how cells sensitive to multiple spatial frequencies, disparities, and orientations are combined by context-sensitive filtering, competition, and cooperation to form coherent BCS boundary segmentations. Several factors contribute to figure-ground pop-out, including: boundary contrast between spatially contiguous boundaries, whether due to scenic differences in luminance, color, spatial frequency, or disparity; partially ordered interactions from larger spatial scales and disparities to smaller scales and disparities; and surface filling-in restricted to regions surrounded by a connected boundary. Phenomena such as 3-D pop-out from a 2-D picture, Da Vinci stereopsis, 3-D neon color spreading, completion of partially occluded objects, and figure-ground reversals are analyzed. The BCS and FCS subsystems model aspects of how the two parvocellular cortical processing streams that join the lateral geniculate nucleus to prestriate cortical area V4 interact to generate a multiplexed representation of Form-And-Color-And-DEpth, or FACADE, within area V4. Area V4 is suggested to support figure-ground separation and to interact with

Fusion in computer vision understanding complex visual content

CERN Document Server

Ionescu, Bogdan; Piatrik, Tomas

2014-01-01

This book presents a thorough overview of fusion in computer vision, from an interdisciplinary and multi-application viewpoint, describing successful approaches, evaluated in the context of international benchmarks that model realistic use cases. Features: examines late fusion approaches for concept recognition in images and videos; describes the interpretation of visual content by incorporating models of the human visual system with content understanding methods; investigates the fusion of multi-modal features of different semantic levels, as well as results of semantic concept detections, fo

Low Vision Aids for Visually Impaired Children

Science.gov (United States)

Schurink, J.; Cox, R. F. A.; Cillessen, A. H. N.; van Rens, G. H. M. B.; Boonstra, F. N.

2011-01-01

It is a widely accepted belief in clinical practice that children with a visual impairment can profit from the use of a low vision aid (LVA). However, we found a considerable gap in our scientific understanding of LVA use, particularly in young children. This is the reason for the analysis presented in this paper. A selected overview of LVA use in…

Visual Peoplemeter: A Vision-based Television Audience Measurement System

Directory of Open Access Journals (Sweden)

SKELIN, A. K.

2014-11-01

Full Text Available Visual peoplemeter is a vision-based measurement system that objectively evaluates the attentive behavior for TV audience rating, thus offering solution to some of drawbacks of current manual logging peoplemeters. In this paper, some limitations of current audience measurement system are reviewed and a novel vision-based system aiming at passive metering of viewers is prototyped. The system uses camera mounted on a television as a sensing modality and applies advanced computer vision algorithms to detect and track a person, and to recognize attentional states. Feasibility of the system is evaluated on a secondary dataset. The results show that the proposed system can analyze viewer's attentive behavior, therefore enabling passive estimates of relevant audience measurement categories.

CRALBP supports the mammalian retinal visual cycle and cone vision.

Science.gov (United States)

Xue, Yunlu; Shen, Susan Q; Jui, Jonathan; Rupp, Alan C; Byrne, Leah C; Hattar, Samer; Flannery, John G; Corbo, Joseph C; Kefalov, Vladimir J

2015-02-01

Mutations in the cellular retinaldehyde-binding protein (CRALBP, encoded by RLBP1) can lead to severe cone photoreceptor-mediated vision loss in patients. It is not known how CRALBP supports cone function or how altered CRALBP leads to cone dysfunction. Here, we determined that deletion of Rlbp1 in mice impairs the retinal visual cycle. Mice lacking CRALBP exhibited M-opsin mislocalization, M-cone loss, and impaired cone-driven visual behavior and light responses. Additionally, M-cone dark adaptation was largely suppressed in CRALBP-deficient animals. While rearing CRALBP-deficient mice in the dark prevented the deterioration of cone function, it did not rescue cone dark adaptation. Adeno-associated virus-mediated restoration of CRALBP expression specifically in Müller cells, but not retinal pigment epithelial (RPE) cells, rescued the retinal visual cycle and M-cone sensitivity in knockout mice. Our results identify Müller cell CRALBP as a key component of the retinal visual cycle and demonstrate that this pathway is important for maintaining normal cone-driven vision and accelerating cone dark adaptation.

The Reliability of the CVI Range: A Functional Vision Assessment for Children with Cortical Visual Impairment

Science.gov (United States)

Newcomb, Sandra

2010-01-01

Children who are identified as visually impaired frequently have a functional vision assessment as one way to determine how their visual impairment affects their educational performance. The CVI Range is a functional vision assessment for children with cortical visual impairment. The purpose of the study presented here was to examine the…

The effect of early visual deprivation on the neural bases of multisensory processing.

Science.gov (United States)

Guerreiro, Maria J S; Putzar, Lisa; Röder, Brigitte

2015-06-01

Developmental vision is deemed to be necessary for the maturation of multisensory cortical circuits. Thus far, this has only been investigated in animal studies, which have shown that congenital visual deprivation markedly reduces the capability of neurons to integrate cross-modal inputs. The present study investigated the effect of transient congenital visual deprivation on the neural mechanisms of multisensory processing in humans. We used functional magnetic resonance imaging to compare responses of visual and auditory cortical areas to visual, auditory and audio-visual stimulation in cataract-reversal patients and normally sighted controls. The results showed that cataract-reversal patients, unlike normally sighted controls, did not exhibit multisensory integration in auditory areas. Furthermore, cataract-reversal patients, but not normally sighted controls, exhibited lower visual cortical processing within visual cortex during audio-visual stimulation than during visual stimulation. These results indicate that congenital visual deprivation affects the capability of cortical areas to integrate cross-modal inputs in humans, possibly because visual processing is suppressed during cross-modal stimulation. Arguably, the lack of vision in the first months after birth may result in a reorganization of visual cortex, including the suppression of noisy visual input from the deprived retina in order to reduce interference during auditory processing. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

From Spoke to Hub: Transforming Organizational Vision and Strategy With Story and Visual Art

Science.gov (United States)

Tyler, Jo A.

2015-01-01

This article reports on a case study at an inner-city nonprofit service agency that inquired into the ways integration of storytelling and visual art as a method of adult learning and way of knowing might influence the process of strategic visioning and planning in a nonprofit organization. The case study focuses on data collected through…

Audible vision for the blind and visually impaired in indoor open spaces.

Science.gov (United States)

Yu, Xunyi; Ganz, Aura

2012-01-01

In this paper we introduce Audible Vision, a system that can help blind and visually impaired users navigate in large indoor open spaces. The system uses computer vision to estimate the location and orientation of the user, and enables the user to perceive his/her relative position to a landmark through 3D audio. Testing shows that Audible Vision can work reliably in real-life ever-changing environment crowded with people.

Association between Visual Impairment and Low Vision and Sleep Duration and Quality among Older Adults in South Africa.

Science.gov (United States)

Peltzer, Karl; Phaswana-Mafuya, Nancy

2017-07-19

This study aims to estimate the association between visual impairment and low vision and sleep duration and poor sleep quality in a national sample of older adults in South Africa. A national population-based cross-sectional Study of Global Ageing and Adults Health (SAGE) wave 1 was conducted in 2008 with a sample of 3840 individuals aged 50 years or older in South Africa. The interviewer-administered questionnaire assessed socio-demographic characteristics, health variables, sleep duration, quality, visual impairment, and vision. Results indicate that 10.0% of the sample reported short sleep duration (≤5 h), 46.6% long sleep (≥9 h), 9.3% poor sleep quality, 8.4% self-reported and visual impairment (near and/or far vision); and 43.2% measured low vision (near and/or far vision) (0.01-0.25 decimal) and 7.5% low vision (0.01-0.125 decimal). In fully adjusted logistic regression models, self-reported visual impairment was associated with short sleep duration and poor sleep quality, separately and together. Low vision was only associated with long sleep duration and poor sleep quality in unadjusted models. Self-reported visual impairment was related to both short sleep duration and poor sleep quality. Population data on sleep patterns may want to include visual impairment measures.

Brain functional network connectivity based on a visual task: visual information processing-related brain regions are significantly activated in the task state

Directory of Open Access Journals (Sweden)

Yan-li Yang

2015-01-01

Full Text Available It is not clear whether the method used in functional brain-network related research can be applied to explore the feature binding mechanism of visual perception. In this study, we investigated feature binding of color and shape in visual perception. Functional magnetic resonance imaging data were collected from 38 healthy volunteers at rest and while performing a visual perception task to construct brain networks active during resting and task states. Results showed that brain regions involved in visual information processing were obviously activated during the task. The components were partitioned using a greedy algorithm, indicating the visual network existed during the resting state. Z-values in the vision-related brain regions were calculated, confirming the dynamic balance of the brain network. Connectivity between brain regions was determined, and the result showed that occipital and lingual gyri were stable brain regions in the visual system network, the parietal lobe played a very important role in the binding process of color features and shape features, and the fusiform and inferior temporal gyri were crucial for processing color and shape information. Experimental findings indicate that understanding visual feature binding and cognitive processes will help establish computational models of vision, improve image recognition technology, and provide a new theoretical mechanism for feature binding in visual perception.

Color vision deficiencies and the child's willingness for visual activity: preliminary research

Science.gov (United States)

Geniusz, Malwina; Szmigiel, Marta; Geniusz, Maciej

2017-09-01

After a few weeks a newborn baby can recognize high contrasts in colors like black and white. They reach full color vision at the age of circa six months. Matching colors is the next milestone. Most children can do it at the age of two. Good color vision is one of the factors which indicate proper development of a child. Presented research shows the correlation between color vision and visual activity. The color vision of a group of children aged 3-8 was examined with saturated Farnsworth D-15. Fransworth test was performed twice - in a standard version and in a magnetic version. The time of completing standard and magnetic tests was measured. Furthermore, parents of subjects answered questions checking the children's visual activity in 1 - 10 scale. Parents stated whether the child willingly watched books, colored coloring books, put puzzles or liked to play with blocks etc. The Fransworth D-15 test designed for color vision testing can be used to test younger children from the age of 3 years. These are preliminary studies which may be a useful tool for further, more accurate examination on a larger group of subjects.

Central and Peripheral Vision Loss Differentially Affects Contextual Cueing in Visual Search

Science.gov (United States)

Geringswald, Franziska; Pollmann, Stefan

2015-01-01

Visual search for targets in repeated displays is more efficient than search for the same targets in random distractor layouts. Previous work has shown that this contextual cueing is severely impaired under central vision loss. Here, we investigated whether central vision loss, simulated with gaze-contingent displays, prevents the incidental…

Are children with low vision adapted to the visual environment in classrooms of mainstream schools?

Science.gov (United States)

Negiloni, Kalpa; Ramani, Krishna Kumar; Jeevitha, R; Kalva, Jayashree; Sudhir, Rachapalle Reddi

2018-02-01

The study aimed to evaluate the classroom environment of children with low vision and provide recommendations to reduce visual stress, with focus on mainstream schooling. The medical records of 110 children (5-17 years) seen in low vision clinic during 1 year period (2015) at a tertiary care center in south India were extracted. The visual function levels of children were compared to the details of their classroom environment. The study evaluated and recommended the chalkboard visual task size and viewing distance required for children with mild, moderate, and severe visual impairment (VI). The major causes of low vision based on the site of abnormality and etiology were retinal (80%) and hereditary (67%) conditions, respectively, in children with mild (n = 18), moderate (n = 72), and severe (n = 20) VI. Many of the children (72%) had difficulty in viewing chalkboard and common strategies used for better visibility included copying from friends (47%) and going closer to chalkboard (42%). To view the chalkboard with reduced visual stress, a child with mild VI can be seated at a maximum distance of 4.3 m from the chalkboard, with the minimum size of visual task (height of lowercase letter writing on chalkboard) recommended to be 3 cm. For 3/60-6/60 range, the maximum viewing distance with the visual task size of 4 cm is recommended to be 85 cm to 1.7 m. Simple modifications of the visual task size and seating arrangements can aid children with low vision with better visibility of chalkboard and reduced visual stress to manage in mainstream schools.

Causes of childhood visual impairment and unmet low-vision care in blind school students in Ghana.

Science.gov (United States)

Ntim-Amponsah, C T; Amoaku, W M K

2008-10-01

The purpose of this study was to determine the causes of childhood visual impairment and blindness in students of a school for blind children, to determine how many students had some residual vision, and to evaluate any unmet low-vision care. A survey of students in the blind school was conducted in two parts in May-June and then October 2003. The sample consisted of 201 students who became blind before the age of 16. Information was obtained from student interviews, doctors' referral notes and ophthalmic examination of all students who consented. Students with residual vision had low-vision assessments. These investigations were supplemented with active participation of the investigators in Parent-Teacher Association meetings and focus group discussions with parents. One hundred and ninety-nine students consented and were recruited, whereas two declined. Ninety-six became visually impaired within their first year of life and 33 by the age of 5 years. Pathology of the cornea and then the lens were the commonest causes of blindness. One hundred and eight students were totally blind, whereas 87 (43.7%) had some residual vision and formed the target for the second part of the study. Fifty-one out of 77 of this target group who turned up for low-vision examination had useful residual vision by the World Health Organisation (WHO) low-vision examination chart. Spectacle magnifiers aided two students to read normal print at N5 and N8, respectively. Different visual aids would help enhance the residual vision in some of the others. Emotional trauma was apparent in parents and teachers. Children who became blind later in life remained in shock for a longer time and adapted less well to their visual impairment. Visual impairment in the population is not uncommon. Some causes are preventable. There is a significant unmet need for low-vision care, particularly amongst children in Ghana, and perhaps many countries in the West Africa subregion. It is hoped that the findings from

Deep Hierarchies in the Primate Visual Cortex: What Can We Learn for Computer Vision?

OpenAIRE

Kruger, Norbert; Janssen, Peter; Kalkan, Sinan; Lappe, Markus; Leonardis, Ales; Piater, Justus; Rodriguez-Sanchez, Antonio J.; Wiskott, Laurenz

2013-01-01

Computational modeling of the primate visual system yields insights of potential relevance to some of the challenges that computer vision is facing, such as object recognition and categorization, motion detection and activity recognition or vision-based navigation and manipulation. This article reviews some functional principles and structures that are generally thought to underlie the primate visual cortex, and attempts to extract biological principles that could further advance computer ...

Vision restoration after brain and retina damage: the "residual vision activation theory".

Science.gov (United States)

Sabel, Bernhard A; Henrich-Noack, Petra; Fedorov, Anton; Gall, Carolin

2011-01-01

Vision loss after retinal or cerebral visual injury (CVI) was long considered to be irreversible. However, there is considerable potential for vision restoration and recovery even in adulthood. Here, we propose the "residual vision activation theory" of how visual functions can be reactivated and restored. CVI is usually not complete, but some structures are typically spared by the damage. They include (i) areas of partial damage at the visual field border, (ii) "islands" of surviving tissue inside the blind field, (iii) extrastriate pathways unaffected by the damage, and (iv) downstream, higher-level neuronal networks. However, residual structures have a triple handicap to be fully functional: (i) fewer neurons, (ii) lack of sufficient attentional resources because of the dominant intact hemisphere caused by excitation/inhibition dysbalance, and (iii) disturbance in their temporal processing. Because of this resulting activation loss, residual structures are unable to contribute much to everyday vision, and their "non-use" further impairs synaptic strength. However, residual structures can be reactivated by engaging them in repetitive stimulation by different means: (i) visual experience, (ii) visual training, or (iii) noninvasive electrical brain current stimulation. These methods lead to strengthening of synaptic transmission and synchronization of partially damaged structures (within-systems plasticity) and downstream neuronal networks (network plasticity). Just as in normal perceptual learning, synaptic plasticity can improve vision and lead to vision restoration. This can be induced at any time after the lesion, at all ages and in all types of visual field impairments after retinal or brain damage (stroke, neurotrauma, glaucoma, amblyopia, age-related macular degeneration). If and to what extent vision restoration can be achieved is a function of the amount of residual tissue and its activation state. However, sustained improvements require repetitive

Two eyes, one vision: binocular motion perception in human visual cortex

NARCIS (Netherlands)

Barendregt, M.

2016-01-01

An important aspect of human vision is the fact that it is binocular, i.e. that we have two eyes. As a result, the brain nearly always receives two slightly different images of the same visual scene. Yet, we only perceive a single image and thus our brain has to actively combine the binocular visual

Seeing in the dark: vision and visual behaviour in nocturnal bees and wasps.

Science.gov (United States)

Warrant, Eric J

2008-06-01

In response to the pressures of predation, parasitism and competition for limited resources, several groups of (mainly) tropical bees and wasps have independently evolved a nocturnal lifestyle. Like their day-active (diurnal) relatives, these insects possess apposition compound eyes, a relatively light-insensitive eye design that is best suited to vision in bright light. Despite this, nocturnal bees and wasps are able to forage at night, with many species capable of flying through a dark and complex forest between the nest and a foraging site, a behaviour that relies heavily on vision and is limited by light intensity. In the two best-studied species - the Central American sweat bee Megalopta genalis (Halictidae) and the Indian carpenter bee Xylocopa tranquebarica (Apidae) - learned visual landmarks are used to guide foraging and homing. Their apposition eyes, however, have only around 30 times greater optical sensitivity than the eyes of their closest diurnal relatives, a fact that is apparently inconsistent with their remarkable nocturnal visual abilities. Moreover, signals generated in the photoreceptors, even though amplified by a high transduction gain, are too noisy and slow to transmit significant amounts of information in dim light. How have nocturnal bees and wasps resolved these paradoxes? Even though this question remains to be answered conclusively, a mounting body of theoretical and experimental evidence suggests that the slow and noisy visual signals generated by the photoreceptors are spatially summed by second-order monopolar cells in the lamina, a process that could dramatically improve visual reliability for the coarser and slower features of the visual world at night.

Colour, vision and ergonomics.

Science.gov (United States)

Pinheiro, Cristina; da Silva, Fernando Moreira

2012-01-01

This paper is based on a research project - Visual Communication and Inclusive Design-Colour, Legibility and Aged Vision, developed at the Faculty of Architecture of Lisbon. The research has the aim of determining specific design principles to be applied to visual communication design (printed) objects, in order to be easily read and perceived by all. This study target group was composed by a selection of socially active individuals, between 55 and 80 years, and we used cultural events posters as objects of study and observation. The main objective is to overlap the study of areas such as colour, vision, older people's colour vision, ergonomics, chromatic contrasts, typography and legibility. In the end we will produce a manual with guidelines and information to apply scientific knowledge into the communication design projectual practice. Within the normal aging process, visual functions gradually decline; the quality of vision worsens, colour vision and contrast sensitivity are also affected. As people's needs change along with age, design should help people and communities, and improve life quality in the present. Applying principles of visually accessible design and ergonomics, the printed design objects, (or interior spaces, urban environments, products, signage and all kinds of visually information) will be effective, easier on everyone's eyes not only for visually impaired people but also for all of us as we age.

Are children with low vision adapted to the visual environment in classrooms of mainstream schools?

Directory of Open Access Journals (Sweden)

Kalpa Negiloni

2018-01-01

Full Text Available Purpose: The study aimed to evaluate the classroom environment of children with low vision and provide recommendations to reduce visual stress, with focus on mainstream schooling. Methods: The medical records of 110 children (5–17 years seen in low vision clinic during 1 year period (2015 at a tertiary care center in south India were extracted. The visual function levels of children were compared to the details of their classroom environment. The study evaluated and recommended the chalkboard visual task size and viewing distance required for children with mild, moderate, and severe visual impairment (VI. Results: The major causes of low vision based on the site of abnormality and etiology were retinal (80% and hereditary (67% conditions, respectively, in children with mild (n = 18, moderate (n = 72, and severe (n = 20 VI. Many of the children (72% had difficulty in viewing chalkboard and common strategies used for better visibility included copying from friends (47% and going closer to chalkboard (42%. To view the chalkboard with reduced visual stress, a child with mild VI can be seated at a maximum distance of 4.3 m from the chalkboard, with the minimum size of visual task (height of lowercase letter writing on chalkboard recommended to be 3 cm. For 3/60–6/60 range, the maximum viewing distance with the visual task size of 4 cm is recommended to be 85 cm to 1.7 m. Conclusion: Simple modifications of the visual task size and seating arrangements can aid children with low vision with better visibility of chalkboard and reduced visual stress to manage in mainstream schools.

Visual cognition

Science.gov (United States)

Cavanagh, Patrick

2011-01-01

Visual cognition, high-level vision, mid-level vision and top-down processing all refer to decision-based scene analyses that combine prior knowledge with retinal input to generate representations. The label “visual cognition” is little used at present, but research and experiments on mid- and high-level, inference-based vision have flourished, becoming in the 21st century a significant, if often understated part, of current vision research. How does visual cognition work? What are its moving parts? This paper reviews the origins and architecture of visual cognition and briefly describes some work in the areas of routines, attention, surfaces, objects, and events (motion, causality, and agency). Most vision scientists avoid being too explicit when presenting concepts about visual cognition, having learned that explicit models invite easy criticism. What we see in the literature is ample evidence for visual cognition, but few or only cautious attempts to detail how it might work. This is the great unfinished business of vision research: at some point we will be done with characterizing how the visual system measures the world and we will have to return to the question of how vision constructs models of objects, surfaces, scenes, and events. PMID:21329719

Visual cognition.

Science.gov (United States)

Cavanagh, Patrick

2011-07-01

Visual cognition, high-level vision, mid-level vision and top-down processing all refer to decision-based scene analyses that combine prior knowledge with retinal input to generate representations. The label "visual cognition" is little used at present, but research and experiments on mid- and high-level, inference-based vision have flourished, becoming in the 21st century a significant, if often understated part, of current vision research. How does visual cognition work? What are its moving parts? This paper reviews the origins and architecture of visual cognition and briefly describes some work in the areas of routines, attention, surfaces, objects, and events (motion, causality, and agency). Most vision scientists avoid being too explicit when presenting concepts about visual cognition, having learned that explicit models invite easy criticism. What we see in the literature is ample evidence for visual cognition, but few or only cautious attempts to detail how it might work. This is the great unfinished business of vision research: at some point we will be done with characterizing how the visual system measures the world and we will have to return to the question of how vision constructs models of objects, surfaces, scenes, and events. Copyright © 2011 Elsevier Ltd. All rights reserved.

Psychological distress and visual functioning in relation to vision-related disability in older individuals with cataracts.

Science.gov (United States)

Walker, J G; Anstey, K J; Lord, S R

2006-05-01

To determine whether demographic, health status and psychological functioning measures, in addition to impaired visual acuity, are related to vision-related disability. Participants were 105 individuals (mean age=73.7 years) with cataracts requiring surgery and corrected visual acuity in the better eye of 6/24 to 6/36 were recruited from waiting lists at three public out-patient ophthalmology clinics. Visual disability was measured with the Visual Functioning-14 survey. Visual acuity was assessed using better and worse eye logMAR scores and the Melbourne Edge Test (MET) for edge contrast sensitivity. Data relating to demographic information, depression, anxiety and stress, health care and medication use and numbers of co-morbid conditions were obtained. Principal component analysis revealed four meaningful factors that accounted for 75% of the variance in visual disability: recreational activities, reading and fine work, activities of daily living and driving behaviour. Multiple regression analyses determined that visual acuity variables were the only significant predictors of overall vision-related functioning and difficulties with reading and fine work. For the remaining visual disability domains, non-visual factors were also significant predictors. Difficulties with recreational activities were predicted by stress, as well as worse eye visual acuity, and difficulties with activities of daily living were associated with self-reported health status, age and depression as well as MET contrast scores. Driving behaviour was associated with sex (with fewer women driving), depression, anxiety and stress scores, and MET contrast scores. Vision-related disability is common in older individuals with cataracts. In addition to visual acuity, demographic, psychological and health status factors influence the severity of vision-related disability, affecting recreational activities, activities of daily living and driving.

CRALBP supports the mammalian retinal visual cycle and cone vision

OpenAIRE

Xue, Yunlu; Shen, Susan Q.; Jui, Jonathan; Rupp, Alan C.; Byrne, Leah C.; Hattar, Samer; Flannery, John G.; Corbo, Joseph C.; Kefalov, Vladimir J.

2015-01-01

Mutations in the cellular retinaldehyde-binding protein (CRALBP, encoded by RLBP1) can lead to severe cone photoreceptor-mediated vision loss in patients. It is not known how CRALBP supports cone function or how altered CRALBP leads to cone dysfunction. Here, we determined that deletion of Rlbp1 in mice impairs the retinal visual cycle. Mice lacking CRALBP exhibited M-opsin mislocalization, M-cone loss, and impaired cone-driven visual behavior and light responses. Additionally, M-cone dark ad...

The role of visual perception measures used in sports vision programmes in predicting actual game performance in Division I collegiate hockey players.

Science.gov (United States)

Poltavski, Dmitri; Biberdorf, David

2015-01-01

Abstract In the growing field of sports vision little is still known about unique attributes of visual processing in ice hockey and what role visual processing plays in the overall athlete's performance. In the present study we evaluated whether visual, perceptual and cognitive/motor variables collected using the Nike SPARQ Sensory Training Station have significant relevance to the real game statistics of 38 Division I collegiate male and female hockey players. The results demonstrated that 69% of variance in the goals made by forwards in 2011-2013 could be predicted by their faster reaction time to a visual stimulus, better visual memory, better visual discrimination and a faster ability to shift focus between near and far objects. Approximately 33% of variance in game points was significantly related to better discrimination among competing visual stimuli. In addition, reaction time to a visual stimulus as well as stereoptic quickness significantly accounted for 24% of variance in the mean duration of the player's penalty time. This is one of the first studies to show that some of the visual skills that state-of-the-art generalised sports vision programmes are purported to target may indeed be important for hockey players' actual performance on the ice.

Speakers of different languages process the visual world differently.

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Chabal, Sarah; Marian, Viorica

2015-06-01

Language and vision are highly interactive. Here we show that people activate language when they perceive the visual world, and that this language information impacts how speakers of different languages focus their attention. For example, when searching for an item (e.g., clock) in the same visual display, English and Spanish speakers look at different objects. Whereas English speakers searching for the clock also look at a cloud, Spanish speakers searching for the clock also look at a gift, because the Spanish names for gift (regalo) and clock (reloj) overlap phonologically. These different looking patterns emerge despite an absence of direct language input, showing that linguistic information is automatically activated by visual scene processing. We conclude that the varying linguistic information available to speakers of different languages affects visual perception, leading to differences in how the visual world is processed. (c) 2015 APA, all rights reserved).

Unsold is unseen … or is it? Examining the role of peripheral vision in the consumer choice process using eye-tracking methodology.

Science.gov (United States)

Wästlund, Erik; Shams, Poja; Otterbring, Tobias

2018-01-01

In visual marketing, the truism that "unseen is unsold" means that products that are not noticed will not be sold. This truism rests on the idea that the consumer choice process is heavily influenced by visual search. However, given that the majority of available products are not seen by consumers, this article examines the role of peripheral vision in guiding attention during the consumer choice process. In two eye-tracking studies, one conducted in a lab facility and the other conducted in a supermarket, the authors investigate the role and limitations of peripheral vision. The results show that peripheral vision is used to direct visual attention when discriminating between target and non-target objects in an eye-tracking laboratory. Target and non-target similarity, as well as visual saliency of non-targets, constitute the boundary conditions for this effect, which generalizes from instruction-based laboratory tasks to preference-based choice tasks in a real supermarket setting. Thus, peripheral vision helps customers to devote a larger share of attention to relevant products during the consumer choice process. Taken together, the results show how the creation of consideration set (sets of possible choice options) relies on both goal-directed attention and peripheral vision. These results could explain how visually similar packaging positively influences market leaders, while making novel brands almost invisible on supermarket shelves. The findings show that even though unsold products might be unseen, in the sense that they have not been directly observed, they might still have been evaluated and excluded by means of peripheral vision. This article is based on controlled lab experiments as well as a field study conducted in a complex retail environment. Thus, the findings are valid both under controlled and ecologically valid conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Gestalten of today: early processing of visual contours and surfaces.

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Kovács, I

1996-12-01

While much is known about the specialized, parallel processing streams of low-level vision that extract primary visual cues, there is only limited knowledge about the dynamic interactions between them. How are the fragments, caught by local analyzers, assembled together to provide us with a unified percept? How are local discontinuities in texture, motion or depth evaluated with respect to object boundaries and surface properties? These questions are presented within the framework of orientation-specific spatial interactions of early vision. Key observations of psychophysics, anatomy and neurophysiology on interactions of various spatial and temporal ranges are reviewed. Aspects of the functional architecture and possible neural substrates of local orientation-specific interactions are discussed, underlining their role in the integration of information across the visual field, and particularly in contour integration. Examples are provided demonstrating that global context, such as contour closure and figure-ground assignment, affects these local interactions. It is illustrated that figure-ground assignment is realized early in visual processing, and that the pattern of early interactions also brings about an effective and sparse coding of visual shape. Finally, it is concluded that the underlying functional architecture is not only dynamic and context dependent, but the pattern of connectivity depends as much on past experience as on actual stimulation.

Lateralized visual behavior in bottlenose dolphins (Tursiops truncatus) performing audio-visual tasks: the right visual field advantage.

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Delfour, F; Marten, K

2006-01-10

Analyzing cerebral asymmetries in various species helps in understanding brain organization. The left and right sides of the brain (lateralization) are involved in different cognitive and sensory functions. This study focuses on dolphin visual lateralization as expressed by spontaneous eye preference when performing a complex cognitive task; we examine lateralization when processing different visual stimuli displayed on an underwater touch-screen (two-dimensional figures, three-dimensional figures and dolphin/human video sequences). Three female bottlenose dolphins (Tursiops truncatus) were submitted to a 2-, 3- or 4-, choice visual/auditory discrimination problem, without any food reward: the subjects had to correctly match visual and acoustic stimuli together. In order to visualize and to touch the underwater target, the dolphins had to come close to the touch-screen and to position themselves using monocular vision (left or right eye) and/or binocular naso-ventral vision. The results showed an ability to associate simple visual forms and auditory information using an underwater touch-screen. Moreover, the subjects showed a spontaneous tendency to use monocular vision. Contrary to previous findings, our results did not clearly demonstrate right eye preference in spontaneous choice. However, the individuals' scores of correct answers were correlated with right eye vision, demonstrating the advantage of this visual field in visual information processing and suggesting a left hemispheric dominance. We also demonstrated that the nature of the presented visual stimulus does not seem to have any influence on the animals' monocular vision choice.

Deep recurrent neural network reveals a hierarchy of process memory during dynamic natural vision.

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Shi, Junxing; Wen, Haiguang; Zhang, Yizhen; Han, Kuan; Liu, Zhongming

2018-05-01

The human visual cortex extracts both spatial and temporal visual features to support perception and guide behavior. Deep convolutional neural networks (CNNs) provide a computational framework to model cortical representation and organization for spatial visual processing, but unable to explain how the brain processes temporal information. To overcome this limitation, we extended a CNN by adding recurrent connections to different layers of the CNN to allow spatial representations to be remembered and accumulated over time. The extended model, or the recurrent neural network (RNN), embodied a hierarchical and distributed model of process memory as an integral part of visual processing. Unlike the CNN, the RNN learned spatiotemporal features from videos to enable action recognition. The RNN better predicted cortical responses to natural movie stimuli than the CNN, at all visual areas, especially those along the dorsal stream. As a fully observable model of visual processing, the RNN also revealed a cortical hierarchy of temporal receptive window, dynamics of process memory, and spatiotemporal representations. These results support the hypothesis of process memory, and demonstrate the potential of using the RNN for in-depth computational understanding of dynamic natural vision. © 2018 Wiley Periodicals, Inc.

Neural Summation in the Hawkmoth Visual System Extends the Limits of Vision in Dim Light.

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Stöckl, Anna Lisa; O'Carroll, David Charles; Warrant, Eric James

2016-03-21

Most of the world's animals are active in dim light and depend on good vision for the tasks of daily life. Many have evolved visual adaptations that permit a performance superior to that of manmade imaging devices [1]. In insects, a major model visual system, nocturnal species show impressive visual abilities ranging from flight control [2, 3], to color discrimination [4, 5], to navigation using visual landmarks [6-8] or dim celestial compass cues [9, 10]. In addition to optical adaptations that improve their sensitivity in dim light [11], neural summation of light in space and time-which enhances the coarser and slower features of the scene at the expense of noisier finer and faster features-has been suggested to improve sensitivity in theoretical [12-14], anatomical [15-17], and behavioral [18-20] studies. How these summation strategies function neurally is, however, presently unknown. Here, we quantified spatial and temporal summation in the motion vision pathway of a nocturnal hawkmoth. We show that spatial and temporal summation combine supralinearly to substantially increase contrast sensitivity and visual information rate over four decades of light intensity, enabling hawkmoths to see at light levels 100 times dimmer than without summation. Our results reveal how visual motion is calculated neurally in dim light and how spatial and temporal summation improve sensitivity while simultaneously maximizing spatial and temporal resolution, thus extending models of insect motion vision derived predominantly from diurnal flies. Moreover, the summation strategies we have revealed may benefit manmade vision systems optimized for variable light levels [21]. Copyright © 2016 Elsevier Ltd. All rights reserved.

Visual system plasticity in mammals: the story of monocular enucleation-induced vision loss

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Nys, Julie; Scheyltjens, Isabelle; Arckens, Lutgarde

2015-01-01

The groundbreaking work of Hubel and Wiesel in the 1960’s on ocular dominance plasticity instigated many studies of the visual system of mammals, enriching our understanding of how the development of its structure and function depends on high quality visual input through both eyes. These studies have mainly employed lid suturing, dark rearing and eye patching applied to different species to reduce or impair visual input, and have created extensive knowledge on binocular vision. However, not all aspects and types of plasticity in the visual cortex have been covered in full detail. In that regard, a more drastic deprivation method like enucleation, leading to complete vision loss appears useful as it has more widespread effects on the afferent visual pathway and even on non-visual brain regions. One-eyed vision due to monocular enucleation (ME) profoundly affects the contralateral retinorecipient subcortical and cortical structures thereby creating a powerful means to investigate cortical plasticity phenomena in which binocular competition has no vote.In this review, we will present current knowledge about the specific application of ME as an experimental tool to study visual and cross-modal brain plasticity and compare early postnatal stages up into adulthood. The structural and physiological consequences of this type of extensive sensory loss as documented and studied in several animal species and human patients will be discussed. We will summarize how ME studies have been instrumental to our current understanding of the differentiation of sensory systems and how the structure and function of cortical circuits in mammals are shaped in response to such an extensive alteration in experience. In conclusion, we will highlight future perspectives and the clinical relevance of adding ME to the list of more longstanding deprivation models in visual system research. PMID:25972788

Does functional vision behave differently in low-vision patients with diabetic retinopathy?--A case-matched study.

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Ahmadian, Lohrasb; Massof, Robert

2008-09-01

A retrospective case-matched study designed to compare patients with diabetic retinopathy (DR) and other ocular diseases, managed in a low-vision clinic, in four different types of functional vision. Reading, mobility, visual motor, and visual information processing were measured in the patients (n = 114) and compared with those in patients with other ocular diseases (n = 114) matched in sex, visual acuity (VA), general health status, and age, using the Activity Inventory as a Rasch-scaled measurement tool. Binocular distance visual acuity was categorized as normal (20/12.5-20/25), near normal (20/32-20/63), moderate (20/80-20/160), severe (20/200-20/400), profound (20/500-20/1000), and total blindness (20/1250 to no light perception). Both Wilcoxon matched pairs signed rank test and the sign test of matched pairs were used to compare estimated functional vision measures between DR cases and controls. Cases ranged in age from 19 to 90 years (mean age, 67.5), and 59% were women. The mean visual acuity (logMar scale) was 0.7. Based on the Wilcoxon signed rank test analyses and after adjusting the probability for multiple comparisons, there was no statistically significant difference (P > 0.05) between patients with DR and control subjects in any of four functional visions. Furthermore, diabetic retinopathy patients did not differ (P > 0.05) from their matched counterparts in goal-level vision-related functional ability and total visual ability. Visual impairment in patients with DR appears to be a generic and non-disease-specific outcome that can be explained mainly by the end impact of the disease in the patients' daily lives and not by the unique disease process that results in the visual impairment.

Vision In Stroke cohort: Profile overview of visual impairment.

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Rowe, Fiona J

2017-11-01

To profile the full range of visual disorders from a large prospective observation study of stroke survivors referred by stroke multidisciplinary teams to orthoptic services with suspected visual problems. Multicenter prospective study undertaken in 20 acute Trust hospitals. Standardized screening/referral forms and investigation forms documented data on referral signs and symptoms plus type and extent of visual impairment. Of 1,345 patients referred with suspected visual impairment, 915 were recruited (59% men; mean age at stroke onset 69 years [SD 14]). Initial visual assessment was at median 22 days post stroke onset. Eight percent had normal visual assessment. Of 92% with confirmed visual impairment, 24% had reduced central visual acuity visual field loss was present in 52%, most commonly homonymous hemianopia. Fifteen percent had visual inattention and 4.6% had other visual perceptual disorders. Overall 84% were visually symptomatic with visual field loss the most common complaint followed by blurred vision, reading difficulty, and diplopia. Treatment options were provided to all with confirmed visual impairment. Targeted advice was most commonly provided along with refraction, prisms, and occlusion. There are a wide range of visual disorders that occur following stroke and, frequently, with visual symptoms. There are equally a wide variety of treatment options available for these individuals. All stroke survivors require screening for visual impairment and warrant referral for specialist assessment and targeted treatment specific to the type of visual impairment.

Investigating category- and shape-selective neural processing in ventral and dorsal visual stream under interocular suppression.

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Ludwig, Karin; Kathmann, Norbert; Sterzer, Philipp; Hesselmann, Guido

2015-01-01

Recent behavioral and neuroimaging studies using continuous flash suppression (CFS) have suggested that action-related processing in the dorsal visual stream might be independent of perceptual awareness, in line with the "vision-for-perception" versus "vision-for-action" distinction of the influential dual-stream theory. It remains controversial if evidence suggesting exclusive dorsal stream processing of tool stimuli under CFS can be explained by their elongated shape alone or by action-relevant category representations in dorsal visual cortex. To approach this question, we investigated category- and shape-selective functional magnetic resonance imaging-blood-oxygen level-dependent responses in both visual streams using images of faces and tools. Multivariate pattern analysis showed enhanced decoding of elongated relative to non-elongated tools, both in the ventral and dorsal visual stream. The second aim of our study was to investigate whether the depth of interocular suppression might differentially affect processing in dorsal and ventral areas. However, parametric modulation of suppression depth by varying the CFS mask contrast did not yield any evidence for differential modulation of category-selective activity. Together, our data provide evidence for shape-selective processing under CFS in both dorsal and ventral stream areas and, therefore, do not support the notion that dorsal "vision-for-action" processing is exclusively preserved under interocular suppression. © 2014 Wiley Periodicals, Inc.

Functional vision loss: a diagnosis of exclusion.

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Villegas, Rex B; Ilsen, Pauline F

2007-10-01

Most cases of visual acuity or visual field loss can be attributed to ocular pathology or ocular manifestations of systemic pathology. They can also occasionally be attributed to nonpathologic processes or malingering. Functional vision loss is any decrease in vision the origin of which cannot be attributed to a pathologic or structural abnormality. Two cases of functional vision loss are described. In the first, a 58-year-old man presented for a baseline eye examination for enrollment in a vision rehabilitation program. He reported bilateral blindness since a motor vehicle accident with head trauma 4 years prior. Entering visual acuity was "no light perception" in each eye. Ocular health examination was normal and the patient made frequent eye contact with the examiners. He was referred for neuroimaging and electrophysiologic testing. The second case was a 49-year-old man who presented with a long history of intermittent monocular diplopia. His medical history was significant for psycho-medical evaluations and a diagnosis of factitious disorder. Entering uncorrected visual acuities were 20/20 in each eye, but visual field testing found constriction. No abnormalities were found that could account for the monocular diplopia or visual field deficit. A diagnosis of functional vision loss secondary to factitious disorder was made. Functional vision loss is a diagnosis of exclusion. In the event of reduced vision in the context of a normal ocular health examination, all other pathology must be ruled out before making the diagnosis of functional vision loss. Evaluation must include auxiliary ophthalmologic testing, neuroimaging of the visual pathway, review of the medical history and lifestyle, and psychiatric evaluation. Comanagement with a psychiatrist is essential for patients with functional vision loss.

A review of the evolution of animal colour vision and visual communication signals.

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Osorio, D; Vorobyev, M

2008-09-01

The visual displays of animals and plants are often colourful, and colour vision allows animals to respond to these signals as they forage for food, choose mates and so-forth. This article discusses the evolutionary relationship between photoreceptor spectral sensitivities of four groups of land animals--birds, butterflies, primates and hymenopteran insects (bees and wasps)--, the colour signals that are relevant to them, and how understanding is informed by models of spectral coding and colour vision. Although the spectral sensitivities of photoreceptors are known to vary adaptively under natural selection there is little evidence that those of hymenopterans, birds and primates are specifically adapted to the reflectance spectra of food plants or animal visual signals. On the other hand, the colours of fruit, flowers and feathers may have evolved to be more discriminable for the colour vision of their natural receivers than for other groups of animals. Butterflies are unusual in that they have enjoyed a major radiation in receptor numbers and spectral sensitivities. The reasons for the radiation and diversity of butterfly colour vision remain unknown, but may include their need to find food plants and to select mates.

Improvement in distance and near visual acuities using low vision devices in diabetic retinopathy

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Sarika Gopalakrishnan

2017-01-01

Full Text Available Purpose: The aim of this study is to elucidate the causes and level of visual impairment (VI in patients with different pathologies of diabetic retinopathy (DR who presented to a low vision care (LVC clinic, to analyze the type of distant and near devices prescribed to them and the visual benefits thereof. Methods: A retrospective chart review was done for 100 consecutive patients with DR who were referred to the LVC clinic from June 2015 to June 2016. The reason for referral was assessed from the electronic medical records and available fundus photographs, fundus fluorescein angiograms, and optical coherence tomography images by a retina specialist. The details of low-vision devices and subsequent improvements were noted. Results: Of the 100 patients, 52% had moderate VI, 19% mild VI, 16% severe VI, and 13% had profound VI or blindness. The most commonly prescribed low vision device was half-eye spectacles (38.4%. The pathologies which had statistically significant improvement (P < 0.05 in distance vision with low vision devices were DR with disc pallor (4.4% improvement, ischemic maculopathy (11.9% improvement, and plaque of hard exudate (10.1% improvement. However, in all pathologies, there was statistically significant improvement (P < 0.05 in near vision. Conclusion: Usually, the patients with DR presented to the LVC clinic with moderate VI. The use of low vision devices can help these patients in cases where medical and surgical treatment have no or a limited role in restoring useful vision.

The CCH Vision Stimulation Program for Infants with Low Vision: Preliminary Results.

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Leguire, L. E.; And Others

1992-01-01

This study evaluated the Columbus (Ohio) Children's Hospital vision stimulation program, involving in-home intervention with 15 visually impaired infants. Comparison with controls indicated benefits of appropriate vision stimulation in increasing the neural foundation for vision and visual-motor function in visually impaired infants. (Author/DB)

A randomised comparison between an inexpensive, general-purpose headlight and a purpose-built surgical headlight on users' visual acuity and colour vision.

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Street, I; Sayles, M; Nistor, M; McRae, A R

2014-02-01

To determine if there are any differences in near visual acuity and colour vision between an inexpensive general-purpose light emitting diode (LED) headlight and a purpose-built surgical LED headlight. A prospective study was conducted sequentially comparing near visual acuity and colour vision, the headlights being tested in random order, in a testing room with a constant minimal amount of background light. The participants were NHS employee volunteers, with self-declared normal (or corrected) vision, working in occupations requiring full literacy. For visual acuity, outcome was measured by recording the smallest font legible when using each headlight when the subject read a near visual acuity test card. For colour vision, the outcome was passing or failing the Ishihara test. There was no statistically significant difference between the general-purpose and the purpose-built headlights in users' near visual acuity or colour vision.

Tensors in image processing and computer vision

CERN Document Server

De Luis García, Rodrigo; Tao, Dacheng; Li, Xuelong

2009-01-01

Tensor signal processing is an emerging field with important applications to computer vision and image processing. This book presents the developments in this branch of signal processing, offering research and discussions by experts in the area. It is suitable for advanced students working in the area of computer vision and image processing.

Adjustment to acquired vision loss in adults presenting for visual disability certification.

Science.gov (United States)

Nakade, Aditya; Rohatgi, Jolly; Bhatia, Manjeet S; Dhaliwal, Upreet

2017-03-01

Rehabilitation of the visually disabled depends on how they adjust to loss; understanding contributing factors may help in effective rehabilitation. The aim of this study is to assess adjustment to acquired vision loss in adults. This observational study, conducted in the Department of Ophthalmology at a tertiary-level teaching hospital, included thirty persons (25-65 years) with visual disability, might contribute to reducing stress and depression.

Front-end vision and multi-scale image analysis multi-scale computer vision theory and applications, written in Mathematica

CERN Document Server

Romeny, Bart M Haar

2008-01-01

Front-End Vision and Multi-Scale Image Analysis is a tutorial in multi-scale methods for computer vision and image processing. It builds on the cross fertilization between human visual perception and multi-scale computer vision (`scale-space') theory and applications. The multi-scale strategies recognized in the first stages of the human visual system are carefully examined, and taken as inspiration for the many geometric methods discussed. All chapters are written in Mathematica, a spectacular high-level language for symbolic and numerical manipulations. The book presents a new and effective

The Effect of Gender and Level of Vision on the Physical Activity Level of Children and Adolescents with Visual Impairment

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Aslan, Ummuhan Bas; Calik, Bilge Basakci; Kitis, Ali

2012-01-01

This study was planned in order to determine physical activity levels of visually impaired children and adolescents and to investigate the effect of gender and level of vision on physical activity level in visually impaired children and adolescents. A total of 30 visually impaired children and adolescents (16 low vision and 14 blind) aged between…

Changes in neurophysiologic markers of visual processing following beneficial anti-VEGF treatment in macular degeneration

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Vottonen P

2013-02-01

Full Text Available Pasi Vottonen,1 Kai Kaarniranta,1,2 Ari Pääkkönen,3 Ina M Tarkka41Department of Ophthalmology, Kuopio University Hospital, Kuopio, Finland; 2Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; 3Department of Clinical Neurophysiology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland; 4Department of Health Sciences, University of Jyväskylä, Jyväskylä, FinlandPurpose: Antivascular endothelial growth factor (VEGF agents have been shown to improve visual acuity and prevent vision loss in exudative age-related macular degeneration. As the vision improves relatively quickly in response to intravitreal injections, we wanted to know whether this improvement is reflected in electrophysiological markers of visual cortical processing.Patients and methods: Our interventional case series included six elderly patients who underwent injection treatment to the affected eye. Their visual acuity, tomographic images of retinal thickness, and visual evoked potentials (VEP were assessed before treatment and six weeks after the last injection.Results: All patients showed improved visual acuity and reduced retinal fluid after the treatment. All but one patient showed increased VEP P100 component amplitudes and/or shortened latencies in the treated eye. These VEP changes were consistent with improved vision while the untreated eyes showed no changes.Conclusions: Our results indicate that antivascular endothelial growth factor injections improved visual function of the treated eyes both in the level of the retina and in the level of visual cortical processing.Keywords: age-related eye diseases, exudative age-related macular degeneration, visual evoked potentials, scalp-recorded EEG, visual acuity

Visual acuity and contrast sensitivity are two important factors affecting vision-related quality of life in advanced age-related macular degeneration.

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Roh, Miin; Selivanova, Alexandra; Shin, Hyun Joon; Miller, Joan W; Jackson, Mary Lou

2018-01-01

Vision loss from age-related macular degeneration (AMD) has a profound effect on vision-related quality of life (VRQoL). The pupose of this study is to identify clinical factors associated with VRQoL using the Rasch- calibrated NEI VFQ-25 scales in bilateral advanced AMD patients. We retrospectively reviewed 47 patients (mean age 83.2 years) with bilateral advanced AMD. Clinical assessment included age, gender, type of AMD, high contrast visual acuity (VA), history of medical conditions, contrast sensitivity (CS), central visual field loss, report of Charles Bonnet Syndrome, current treatment for AMD and Rasch-calibrated NEI VFQ-25 visual function and socioemotional function scales. The NEI VFQ visual function scale includes items of general vision, peripheral vision, distance vision and near vision-related activity while the socioemotional function scale includes items of vision related-social functioning, role difficulties, dependency, and mental health. Multiple regression analysis (structural regression model) was performed using fixed item parameters obtained from the one-parameter item response theory model. Multivariate analysis showed that high contrast VA and CS were two factors influencing VRQoL visual function scale (β = -0.25, 95% CI-0.37 to -0.12, p<0.001 and β = 0.35, 95% CI 0.25 to 0.46, p<0.001) and socioemontional functioning scale (β = -0.2, 95% CI -0.37 to -0.03, p = 0.023, and β = 0.3, 95% CI 0.18 to 0.43, p = 0.001). Central visual field loss was not assoicated with either VRQoL visual or socioemontional functioning scale (β = -0.08, 95% CI-0.28 to 0.12,p = 0.44 and β = -0.09, 95% CI -0.03 to 0.16, p = 0.50, respectively). In patients with vision impairment secondary to bilateral advanced AMD, high contrast VA and CS are two important factors affecting VRQoL.

Conceptual analysis of Physiology of vision in Ayurveda

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Praveen Balakrishnan

2014-01-01

Full Text Available The process by which the world outside is seen is termed as visual process or physiology of vision. There are three phases in this visual process: phase of refraction of light, phase of conversion of light energy into electrical impulse and finally peripheral and central neurophysiology. With the advent of modern instruments step by step biochemical changes occurring at each level of the visual process has been deciphered. Many investigations have emerged to track these changes and helping to diagnose the exact nature of the disease. Ayurveda has described this physiology of vision based on the functions of vata and pitta. Philosophical textbook of ayurveda, Tarka Sangraha, gives certain basics facts of visual process. This article discusses the second and third phase of visual process. Step by step analysis of the visual process through the spectacles of ayurveda amalgamated with the basics of philosophy from Tarka Sangraha has been analyzed critically to generate a concrete idea regarding the physiology and hence thereby interpret the pathology on the grounds of ayurveda based on the investigative reports.

Reaction time for processing visual stimulus in a computer-assisted rehabilitation environment.

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Sanchez, Yerly; Pinzon, David; Zheng, Bin

2017-10-01

To examine the reaction time when human subjects process information presented in the visual channel under both a direct vision and a virtual rehabilitation environment when walking was performed. Visual stimulus included eight math problems displayed on the peripheral vision to seven healthy human subjects in a virtual rehabilitation training (computer-assisted rehabilitation environment (CAREN)) and a direct vision environment. Subjects were required to verbally report the results of these math calculations in a short period of time. Reaction time measured by Tobii Eye tracker and calculation accuracy were recorded and compared between the direct vision and virtual rehabilitation environment. Performance outcomes measured for both groups included reaction time, reading time, answering time and the verbal answer score. A significant difference between the groups was only found for the reaction time (p = .004). Participants had more difficulty recognizing the first equation of the virtual environment. Participants reaction time was faster in the direct vision environment. This reaction time delay should be kept in mind when designing skill training scenarios in virtual environments. This was a pilot project to a series of studies assessing cognition ability of stroke patients who are undertaking a rehabilitation program with a virtual training environment. Implications for rehabilitation Eye tracking is a reliable tool that can be employed in rehabilitation virtual environments. Reaction time changes between direct vision and virtual environment.

A Visual Profile of Queensland Indigenous Children.

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Hopkins, Shelley; Sampson, Geoff P; Hendicott, Peter L; Wood, Joanne M

2016-03-01

Little is known about the prevalence of refractive error, binocular vision, and other visual conditions in Australian Indigenous children. This is important given the association of these visual conditions with reduced reading performance in the wider population, which may also contribute to the suboptimal reading performance reported in this population. The aim of this study was to develop a visual profile of Queensland Indigenous children. Vision testing was performed on 595 primary schoolchildren in Queensland, Australia. Vision parameters measured included visual acuity, refractive error, color vision, nearpoint of convergence, horizontal heterophoria, fusional vergence range, accommodative facility, AC/A ratio, visual motor integration, and rapid automatized naming. Near heterophoria, nearpoint of convergence, and near fusional vergence range were used to classify convergence insufficiency (CI). Although refractive error (Indigenous, 10%; non-Indigenous, 16%; p = 0.04) and strabismus (Indigenous, 0%; non-Indigenous, 3%; p = 0.03) were significantly less common in Indigenous children, CI was twice as prevalent (Indigenous, 10%; non-Indigenous, 5%; p = 0.04). Reduced visual information processing skills were more common in Indigenous children (reduced visual motor integration [Indigenous, 28%; non-Indigenous, 16%; p < 0.01] and slower rapid automatized naming [Indigenous, 67%; non-Indigenous, 59%; p = 0.04]). The prevalence of visual impairment (reduced visual acuity) and color vision deficiency was similar between groups. Indigenous children have less refractive error and strabismus than their non-Indigenous peers. However, CI and reduced visual information processing skills were more common in this group. Given that vision screenings primarily target visual acuity assessment and strabismus detection, this is an important finding as many Indigenous children with CI and reduced visual information processing may be missed. Emphasis should be placed on identifying

Machine Vision Handbook

CERN Document Server

2012-01-01

The automation of visual inspection is becoming more and more important in modern industry as a consistent, reliable means of judging the quality of raw materials and manufactured goods . The Machine Vision Handbook  equips the reader with the practical details required to engineer integrated mechanical-optical-electronic-software systems. Machine vision is first set in the context of basic information on light, natural vision, colour sensing and optics. The physical apparatus required for mechanized image capture – lenses, cameras, scanners and light sources – are discussed followed by detailed treatment of various image-processing methods including an introduction to the QT image processing system. QT is unique to this book, and provides an example of a practical machine vision system along with extensive libraries of useful commands, functions and images which can be implemented by the reader. The main text of the book is completed by studies of a wide variety of applications of machine vision in insp...

Computer and visual display terminals (VDT) vision syndrome (CVDTS).

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Parihar, J K S; Jain, Vaibhav Kumar; Chaturvedi, Piyush; Kaushik, Jaya; Jain, Gunjan; Parihar, Ashwini K S

2016-07-01

Computer and visual display terminals have become an essential part of modern lifestyle. The use of these devices has made our life simple in household work as well as in offices. However the prolonged use of these devices is not without any complication. Computer and visual display terminals syndrome is a constellation of symptoms ocular as well as extraocular associated with prolonged use of visual display terminals. This syndrome is gaining importance in this modern era because of the widespread use of technologies in day-to-day life. It is associated with asthenopic symptoms, visual blurring, dry eyes, musculoskeletal symptoms such as neck pain, back pain, shoulder pain, carpal tunnel syndrome, psychosocial factors, venous thromboembolism, shoulder tendonitis, and elbow epicondylitis. Proper identification of symptoms and causative factors are necessary for the accurate diagnosis and management. This article focuses on the various aspects of the computer vision display terminals syndrome described in the previous literature. Further research is needed for the better understanding of the complex pathophysiology and management.

Vision affects tactile target and distractor processing even when space is task-irrelevant

Directory of Open Access Journals (Sweden)

Ann-Katrin eWesslein

2014-02-01

Full Text Available The human brain is adapted to integrate the information from multiple sensory modalities into coherent, robust representations of the objects and events in the external world. A large body of empirical research has demonstrated the ubiquitous nature of the interactions that take place between vision and touch, with the former typically dominating over the latter. Many studies have investigated the influence of visual stimuli on the processing of tactile stimuli (and vice versa. Other studies, meanwhile, have investigated the effect of directing a participant’s gaze either toward or else away from the body-part receiving the target tactile stimulation. Other studies, by contrast, have compared performance in those conditions in which the participant’s eyes have been open versus closed. We start by reviewing the research that has been published to date demonstrating the influence of vision on the processing of tactile targets, that is, on those stimuli that have to be attended or responded to. We outline that many – but not all – of the visuotactile interactions that have been observed to date may be attributable to the direction of spatial attention. We then move on to focus on the crossmodal influence of vision, as well as of the direction of gaze, on the processing of tactile distractors. We highlight the results of those studies demonstrating the influence of vision, rather than gaze direction (i.e., the direction of overt spatial attention, on tactile distractor processing (e.g., tactile variants of the negative-priming or flanker task. The conclusion is that no matter how vision of a tactile distractor is engaged, the result would appear to be the same, namely that tactile distractors are processed more thoroughly.

Embedding visual routines in AnaFocus' Eye-RIS Vision Systems for closing the perception to action loop in roving robots

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Jiménez-Marrufo, A.; Caballero-García, D. J.

2011-05-01

The purpose of the current paper is to describe how different visual routines can be developed and embedded in the AnaFocus' Eye-RIS Vision System on Chip (VSoC) to close the perception to action loop within the roving robots developed under the framework of SPARK II European project. The Eye-RIS Vision System on Chip employs a bio-inspired architecture where image acquisition and processing are truly intermingled and the processing itself is carried out in two steps. At the first step, processing is fully parallel owing to the concourse of dedicated circuit structures which are integrated close to the sensors. At the second step, processing is realized on digitally-coded information data by means of digital processors. All these capabilities make the Eye-RIS VSoC very suitable for the integration within small robots in general, and within the robots developed by the SPARK II project in particular. These systems provide with image-processing capabilities and speed comparable to high-end conventional vision systems without the need for high-density image memory and intensive digital processing. As far as perception is concerned, current perceptual schemes are often based on information derived from visual routines. Since real world images are quite complex to be processed for perceptual needs with traditional approaches, more computationally feasible algorithms are required to extract the desired features from the scene in real time, to efficiently proceed with the consequent action. In this paper the development of such algorithms and their implementation taking full advantage of the sensing-processing capabilities of the Eye-RIS VSoC are described.

Low Vision Devices and Training

Directory of Open Access Journals (Sweden)

Imran Azam Butt

2004-01-01

Full Text Available Vision is the ability to see with a clear perception of detail, colour and contrast, and to distinguish objects visually. Like any other sense, vision tends to deteriorate or diminish naturally with age. In most cases, reduction in visual capability can be corrected with glasses, medicine or surgery. However, if the visual changes occur because of an incurable eye disease, condition or injury, vision loss can be permanent. Many people around the world with permanent visual impairment have some residual vision which can be used with the help of low vision services, materials and devices. This paper describes different options for the enhancement of residual vision including optical and non-optical devices and providing training for the low vision client.

Basic quantitative assessment of visual performance in patients with very low vision.

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Bach, Michael; Wilke, Michaela; Wilhelm, Barbara; Zrenner, Eberhart; Wilke, Robert

2010-02-01

A variety of approaches to developing visual prostheses are being pursued: subretinal, epiretinal, via the optic nerve, or via the visual cortex. This report presents a method of comparing their efficacy at genuinely improving visual function, starting at no light perception (NLP). A test battery (a computer program, Basic Assessment of Light and Motion [BaLM]) was developed in four basic visual dimensions: (1) light perception (light/no light), with an unstructured large-field stimulus; (2) temporal resolution, with single versus double flash discrimination; (3) localization of light, where a wedge extends from the center into four possible directions; and (4) motion, with a coarse pattern moving in one of four directions. Two- or four-alternative, forced-choice paradigms were used. The participants' responses were self-paced and delivered with a keypad. The feasibility of the BaLM was tested in 73 eyes of 51 patients with low vision. The light and time test modules discriminated between NLP and light perception (LP). The localization and motion modules showed no significant response for NLP but discriminated between LP and hand movement (HM). All four modules reached their ceilings in the acuity categories higher than HM. BaLM results systematically differed between the very-low-acuity categories NLP, LP, and HM. Light and time yielded similar results, as did localization and motion; still, for assessing the visual prostheses with differing temporal characteristics, they are not redundant. The results suggest that this simple test battery provides a quantitative assessment of visual function in the very-low-vision range from NLP to HM.

Improving Mobility Performance in Low Vision With a Distance-Based Representation of the Visual Scene.

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van Rheede, Joram J; Wilson, Iain R; Qian, Rose I; Downes, Susan M; Kennard, Christopher; Hicks, Stephen L

2015-07-01

Severe visual impairment can have a profound impact on personal independence through its effect on mobility. We investigated whether the mobility of people with vision low enough to be registered as blind could be improved by presenting the visual environment in a distance-based manner for easier detection of obstacles. We accomplished this by developing a pair of "residual vision glasses" (RVGs) that use a head-mounted depth camera and displays to present information about the distance of obstacles to the wearer as brightness, such that obstacles closer to the wearer are represented more brightly. We assessed the impact of the RVGs on the mobility performance of visually impaired participants during the completion of a set of obstacle courses. Participant position was monitored continuously, which enabled us to capture the temporal dynamics of mobility performance. This allowed us to find correlates of obstacle detection and hesitations in walking behavior, in addition to the more commonly used measures of trial completion time and number of collisions. All participants were able to use the smart glasses to navigate the course, and mobility performance improved for those visually impaired participants with the worst prior mobility performance. However, walking speed was slower and hesitations increased with the altered visual representation. A depth-based representation of the visual environment may offer low vision patients improvements in independent mobility. It is important for further work to explore whether practice can overcome the reductions in speed and increased hesitation that were observed in our trial.

Severe structural and functional visual system damage leads to profound loss of vision-related quality of life in patients with neuromyelitis optica spectrum disorders.

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Schmidt, Felix; Zimmermann, Hanna; Mikolajczak, Janine; Oertel, Frederike C; Pache, Florence; Weinhold, Maria; Schinzel, Johann; Bellmann-Strobl, Judith; Ruprecht, Klemens; Paul, Friedemann; Brandt, Alexander U

2017-01-01

Neuromyelitis optica spectrum disorders (NMOSD) are characterized by devastating optic neuritis attacks causing more structural damage and visual impairment than in multiple sclerosis (MS). The objective of this study was to compare vision-related quality of life in NMOSD and MS patients and correlate it to structural retinal damage and visual function. Thirty-one NMOSD and 31 matched MS patients were included. Vision-related quality of life was assessed with the 39-item National Eye Institute Visual Function Questionnaire (NEI-VFQ). All patients underwent retinal optical coherence tomography and visual acuity and contrast sensitivity measurements. Vision-related quality of life was reduced in NMOSD compared to MS patients. This difference was driven by a higher incidence of bilateral and more severe optic neuritis in the NMOSD group. Retinal thinning and visual impairment were significantly greater in the NMOSD cohort. Lower vision-related quality of life was associated with more retinal damage and reduced visual function as assessed by visual acuity and contrast sensitivity. NMOSD-related bilateral ON-attacks cause severe structural damage and visual impairment that lead to severe loss of vision-related quality of life. The NEI-VFQ is a helpful tool to monitor vision-related quality of life in NMOSD patients. Copyright © 2016 Elsevier B.V. All rights reserved.

Computer Vision and Image Processing: A Paper Review

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victor - wiley

2018-02-01

Full Text Available Computer vision has been studied from many persective. It expands from raw data recording into techniques and ideas combining digital image processing, pattern recognition, machine learning and computer graphics. The wide usage has attracted many scholars to integrate with many disciplines and fields. This paper provide a survey of the recent technologies and theoretical concept explaining the development of computer vision especially related to image processing using different areas of their field application. Computer vision helps scholars to analyze images and video to obtain necessary information,    understand information on events or descriptions, and scenic pattern. It used method of multi-range application domain with massive data analysis. This paper provides contribution of recent development on reviews related to computer vision, image processing, and their related studies. We categorized the computer vision mainstream into four group e.g., image processing, object recognition, and machine learning. We also provide brief explanation on the up-to-date information about the techniques and their performance.

Visual acuity, self-reported vision and falls in the EPIC-Norfolk Eye study

OpenAIRE

Yip, Jennifer L Y; Khawaja, Anthony P; Broadway, David; Luben, Robert; Hayat, Shabina; Dalzell, Nichola; Bhaniani, Amit; Wareham, Nicholas; Khaw, Kay-Tee; Foster, Paul J

2013-01-01

Purpose To examine the relationship between visual acuity (VA) and self-reported vision (SRV) in relation to falls in 8317 participants of the European Prospective Investigation into Cancer-Norfolk Eye study. Methods All participants completed a health questionnaire that included a question regarding SRV and questions regarding the number of falls in the past year. Distance VA was measured using a logMAR chart for each eye. Poor SRV was defined as those reporting fair or poor distance vision....

A sensorimotor account of vision and visual consciousness.

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O'Regan, J K; Noë, A

2001-10-01

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The outside world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the governing laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Several lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual "filling in," visual stability despite eye movements, change blindness, sensory substitution, and color perception.

Features of the Manufacturing Vision Development Process

DEFF Research Database (Denmark)

Dukovska-Popovska, Iskra; Riis, Jens Ove; Boer, Harry

2005-01-01

of action research. The methodology recommends wide participation of people from different hierarchical and functional positions, who engage in a relatively short, playful and creative process and come up with a vision (concept) for the future manufacturing system in the company. Based on three case studies......This paper discusses the key features of the process of Manufacturing Vision Development, a process that enables companies to develop their future manufacturing concept. The basis for the process is a generic five-phase methodology (Riis and Johansen, 2003) developed as a result of ten years...... of companies going through the initial phases of the methodology, this research identified the key features of the Manufacturing Vision Development process. The paper elaborates the key features by defining them, discussing how and when they can appear, and how they influence the process....

Visual acuity and contrast sensitivity are two important factors affecting vision-related quality of life in advanced age-related macular degeneration

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Selivanova, Alexandra; Shin, Hyun Joon; Miller, Joan W.; Jackson, Mary Lou

2018-01-01

Purpose Vision loss from age-related macular degeneration (AMD) has a profound effect on vision-related quality of life (VRQoL). The pupose of this study is to identify clinical factors associated with VRQoL using the Rasch- calibrated NEI VFQ-25 scales in bilateral advanced AMD patients. Methods We retrospectively reviewed 47 patients (mean age 83.2 years) with bilateral advanced AMD. Clinical assessment included age, gender, type of AMD, high contrast visual acuity (VA), history of medical conditions, contrast sensitivity (CS), central visual field loss, report of Charles Bonnet Syndrome, current treatment for AMD and Rasch-calibrated NEI VFQ-25 visual function and socioemotional function scales. The NEI VFQ visual function scale includes items of general vision, peripheral vision, distance vision and near vision-related activity while the socioemotional function scale includes items of vision related-social functioning, role difficulties, dependency, and mental health. Multiple regression analysis (structural regression model) was performed using fixed item parameters obtained from the one-parameter item response theory model. Results Multivariate analysis showed that high contrast VA and CS were two factors influencing VRQoL visual function scale (β = -0.25, 95% CI-0.37 to -0.12, p<0.001 and β = 0.35, 95% CI 0.25 to 0.46, p<0.001) and socioemontional functioning scale (β = -0.2, 95% CI -0.37 to -0.03, p = 0.023, and β = 0.3, 95% CI 0.18 to 0.43, p = 0.001). Central visual field loss was not assoicated with either VRQoL visual or socioemontional functioning scale (β = -0.08, 95% CI-0.28 to 0.12,p = 0.44 and β = -0.09, 95% CI -0.03 to 0.16, p = 0.50, respectively). Conclusion In patients with vision impairment secondary to bilateral advanced AMD, high contrast VA and CS are two important factors affecting VRQoL. PMID:29746512

Where vision meets memory: prefrontal-posterior networks for visual object constancy during categorization and recognition.

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Schendan, Haline E; Stern, Chantal E

2008-07-01

Objects seen from unusual relative to more canonical views require more time to categorize and recognize, and, according to object model verification theories, additionally recruit prefrontal processes for cognitive control that interact with parietal processes for mental rotation. To test this using functional magnetic resonance imaging, people categorized and recognized known objects from unusual and canonical views. Canonical views activated some components of a default network more on categorization than recognition. Activation to unusual views showed that both ventral and dorsal visual pathways, and prefrontal cortex, have key roles in visual object constancy. Unusual views activated object-sensitive and mental rotation (and not saccade) regions in ventrocaudal intraparietal, transverse occipital, and inferotemporal sulci, and ventral premotor cortex for verification processes of model testing on any task. A collateral-lingual sulci "place" area activated for mental rotation, working memory, and unusual views on correct recognition and categorization trials to accomplish detailed spatial matching. Ventrolateral prefrontal cortex and object-sensitive lateral occipital sulcus activated for mental rotation and unusual views on categorization more than recognition, supporting verification processes of model prediction. This visual knowledge framework integrates vision and memory theories to explain how distinct prefrontal-posterior networks enable meaningful interactions with objects in diverse situations.

Spatial vision in older adults: perceptual changes and neural bases.

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McKendrick, Allison M; Chan, Yu Man; Nguyen, Bao N

2018-05-17

The number of older adults is rapidly increasing internationally, leading to a significant increase in research on how healthy ageing impacts vision. Most clinical assessments of spatial vision involve simple detection (letter acuity, grating contrast sensitivity, perimetry). However, most natural visual environments are more spatially complicated, requiring contrast discrimination, and the delineation of object boundaries and contours, which are typically present on non-uniform backgrounds. In this review we discuss recent research that reports on the effects of normal ageing on these more complex visual functions, specifically in the context of recent neurophysiological studies. Recent research has concentrated on understanding the effects of healthy ageing on neural responses within the visual pathway in animal models. Such neurophysiological research has led to numerous, subsequently tested, hypotheses regarding the likely impact of healthy human ageing on specific aspects of spatial vision. Healthy normal ageing impacts significantly on spatial visual information processing from the retina through to visual cortex. Some human data validates that obtained from studies of animal physiology, however some findings indicate that rethinking of presumed neural substrates is required. Notably, not all spatial visual processes are altered by age. Healthy normal ageing impacts significantly on some spatial visual processes (in particular centre-surround tasks), but leaves contrast discrimination, contrast adaptation, and orientation discrimination relatively intact. The study of older adult vision contributes to knowledge of the brain mechanisms altered by the ageing process, can provide practical information regarding visual environments that older adults may find challenging, and may lead to new methods of assessing visual performance in clinical environments. © 2018 The Authors Ophthalmic & Physiological Optics © 2018 The College of Optometrists.

Vision Egg: an open-source library for realtime visual stimulus generation

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Andrew D Straw

2008-11-01

Full Text Available Modern computer hardware makes it possible to produce visual stimuli in ways not previously possible. Arbitrary scenes, from traditional sinusoidal gratings to naturalistic 3D scenes can now be specified on a frame-by-frame basis in realtime. I have developed a programming library called the Vision Egg that aims to make it easy to take advantage of these innovations. The Vision Egg is a free, open-source library making use of OpenGL and written in the high-level language Python with extensions in C. Careful attention has been paid to the issues of luminance and temporal calibration, and several interfacing techniques to input devices such as mice, movement tracking systems, and digital triggers are discussed. Together, these make the Vision Egg suitable for many psychophysical, electrophysiological, and behavioral experiments. This software is available for free download at http://www.visionegg.org/.

Visual performance after bilateral implantation of 2 new presbyopia-correcting intraocular lenses: Trifocal versus extended range of vision.

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Monaco, Gaspare; Gari, Mariangela; Di Censo, Fabio; Poscia, Andrea; Ruggi, Giada; Scialdone, Antonio

2017-06-01

To compare the visual outcomes and quality of vision of 2 new diffractive multifocal intraocular lenses (IOLs) with those of a monofocal IOL. Fatebenefratelli e Oftalmico Hospital, Milan, Italy. Prospective case series. Patients had bilateral cataract surgery with implantation of a trifocal IOL (Panoptix), an extended-range-of-vision IOL (Symfony), or a monofocal IOL (SN60WF). Postoperative examinations included assessing distance, intermediate, and near visual acuity; binocular defocus; intraocular and total aberrations; point-spread function (PSF); modulation transfer function (MTF); retinal straylight; and quality-of-vision (QoV) and spectacle-dependence questionnaires. Seventy-six patients (152 eyes) were assessed for study eligibility. Twenty patients (40 eyes) in each arm of the study (60 patients, 120 eyes) completed the outcome assessment. At the 4-month follow-up, the trifocal group had significantly better near visual acuity than the extended-range-of-vision group (P = .005). The defocus curve showed the trifocal IOL had better intermediate/near performance than the extended-range-of-vision IOL and both multifocal IOLs performed better than the monofocal IOL. Intragroup comparison of the total higher-order aberrations, PSF, MTF, and retinal straylight were not statistically different. The QoV questionnaire results showed no differences in dysphotopsia between the multifocal IOL groups; however, the results were significantly higher than in the monofocal IOL group. Both multifocal IOLs seemed to be good options for patients with intermediate-vision requirements, whereas the trifocal IOL might be better for patients with near-vision requirements. The significant perception of visual side effects indicates that patients still must be counseled about these effects before a multifocal IOL is implanted. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Timing the impact of literacy on visual processing

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Pegado, Felipe; Comerlato, Enio; Ventura, Fabricio; Jobert, Antoinette; Nakamura, Kimihiro; Buiatti, Marco; Ventura, Paulo; Dehaene-Lambertz, Ghislaine; Kolinsky, Régine; Morais, José; Braga, Lucia W.; Cohen, Laurent; Dehaene, Stanislas

2014-01-01

Learning to read requires the acquisition of an efficient visual procedure for quickly recognizing fine print. Thus, reading practice could induce a perceptual learning effect in early vision. Using functional magnetic resonance imaging (fMRI) in literate and illiterate adults, we previously demonstrated an impact of reading acquisition on both high- and low-level occipitotemporal visual areas, but could not resolve the time course of these effects. To clarify whether literacy affects early vs. late stages of visual processing, we measured event-related potentials to various categories of visual stimuli in healthy adults with variable levels of literacy, including completely illiterate subjects, early-schooled literate subjects, and subjects who learned to read in adulthood (ex-illiterates). The stimuli included written letter strings forming pseudowords, on which literacy is expected to have a major impact, as well as faces, houses, tools, checkerboards, and false fonts. To evaluate the precision with which these stimuli were encoded, we studied repetition effects by presenting the stimuli in pairs composed of repeated, mirrored, or unrelated pictures from the same category. The results indicate that reading ability is correlated with a broad enhancement of early visual processing, including increased repetition suppression, suggesting better exemplar discrimination, and increased mirror discrimination, as early as ∼100–150 ms in the left occipitotemporal region. These effects were found with letter strings and false fonts, but also were partially generalized to other visual categories. Thus, learning to read affects the magnitude, precision, and invariance of early visual processing. PMID:25422460

Biologically based machine vision: signal analysis of monopolar cells in the visual system of Musca domestica.

Science.gov (United States)

Newton, Jenny; Barrett, Steven F; Wilcox, Michael J; Popp, Stephanie

2002-01-01

Machine vision for navigational purposes is a rapidly growing field. Many abilities such as object recognition and target tracking rely on vision. Autonomous vehicles must be able to navigate in dynamic enviroments and simultaneously locate a target position. Traditional machine vision often fails to react in real time because of large computational requirements whereas the fly achieves complex orientation and navigation with a relatively small and simple brain. Understanding how the fly extracts visual information and how neurons encode and process information could lead us to a new approach for machine vision applications. Photoreceptors in the Musca domestica eye that share the same spatial information converge into a structure called the cartridge. The cartridge consists of the photoreceptor axon terminals and monopolar cells L1, L2, and L4. It is thought that L1 and L2 cells encode edge related information relative to a single cartridge. These cells are thought to be equivalent to vertebrate bipolar cells, producing contrast enhancement and reduction of information sent to L4. Monopolar cell L4 is thought to perform image segmentation on the information input from L1 and L2 and also enhance edge detection. A mesh of interconnected L4's would correlate the output from L1 and L2 cells of adjacent cartridges and provide a parallel network for segmenting an object's edges. The focus of this research is to excite photoreceptors of the common housefly, Musca domestica, with different visual patterns. The electrical response of monopolar cells L1, L2, and L4 will be recorded using intracellular recording techniques. Signal analysis will determine the neurocircuitry to detect and segment images.

Which visual sight skill tested and developed the interaction between central and peripheral vision case duels dribbling soccer skills

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Zerf Mohammed

2016-09-01

Full Text Available The present paper analyses the effects of visual keep sight to test and develop the interaction between central and peripheral vision the case of duels dribbling among soccer under 17 years. Where This research aims to propose a method evaluating and coaching this skill in the absence of laboratory tests and virtual visual exercises as a way for Algerian coaches to control the progress of their players. From the principle that the team which wins the most duels has the best chance of winning the game. [1] Our research supports the hypothesis which confirms in one hand that Dynamic visual acuity is the combine between Peripheral and Central vision to have one eye on the ball and the other on the defined [2] . While some authors confirm that the Top-class football players do not watch their steps, but dribble with their heads up [3]. Whereas Previous studies confirm estimate of distance ball foot player is the strategy to master this skill [4] which requires the involvement of the commitment of peripheral vision for information and central vision to master the ball [5]. From the proof and results statistics applied in the current study, we confirm that narrow spaces require the interaction of central vision than peripheral vision. Otherwise, free spaces require peripheral vision than the central vision. Which leaves us to confirm that peripheral vision in the limited space [6] can suffer because the player needs to pay close attention to each contact with the ball [7].

Optimization of Visual Information Presentation for Visual Prosthesis

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Fei Guo

2018-01-01

Full Text Available Visual prosthesis applying electrical stimulation to restore visual function for the blind has promising prospects. However, due to the low resolution, limited visual field, and the low dynamic range of the visual perception, huge loss of information occurred when presenting daily scenes. The ability of object recognition in real-life scenarios is severely restricted for prosthetic users. To overcome the limitations, optimizing the visual information in the simulated prosthetic vision has been the focus of research. This paper proposes two image processing strategies based on a salient object detection technique. The two processing strategies enable the prosthetic implants to focus on the object of interest and suppress the background clutter. Psychophysical experiments show that techniques such as foreground zooming with background clutter removal and foreground edge detection with background reduction have positive impacts on the task of object recognition in simulated prosthetic vision. By using edge detection and zooming technique, the two processing strategies significantly improve the recognition accuracy of objects. We can conclude that the visual prosthesis using our proposed strategy can assist the blind to improve their ability to recognize objects. The results will provide effective solutions for the further development of visual prosthesis.

Optimization of Visual Information Presentation for Visual Prosthesis

Science.gov (United States)

Gao, Yong

2018-01-01

Visual prosthesis applying electrical stimulation to restore visual function for the blind has promising prospects. However, due to the low resolution, limited visual field, and the low dynamic range of the visual perception, huge loss of information occurred when presenting daily scenes. The ability of object recognition in real-life scenarios is severely restricted for prosthetic users. To overcome the limitations, optimizing the visual information in the simulated prosthetic vision has been the focus of research. This paper proposes two image processing strategies based on a salient object detection technique. The two processing strategies enable the prosthetic implants to focus on the object of interest and suppress the background clutter. Psychophysical experiments show that techniques such as foreground zooming with background clutter removal and foreground edge detection with background reduction have positive impacts on the task of object recognition in simulated prosthetic vision. By using edge detection and zooming technique, the two processing strategies significantly improve the recognition accuracy of objects. We can conclude that the visual prosthesis using our proposed strategy can assist the blind to improve their ability to recognize objects. The results will provide effective solutions for the further development of visual prosthesis. PMID:29731769

Agnosic vision is like peripheral vision, which is limited by crowding.

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Strappini, Francesca; Pelli, Denis G; Di Pace, Enrico; Martelli, Marialuisa

2017-04-01

Visual agnosia is a neuropsychological impairment of visual object recognition despite near-normal acuity and visual fields. A century of research has provided only a rudimentary account of the functional damage underlying this deficit. We find that the object-recognition ability of agnosic patients viewing an object directly is like that of normally-sighted observers viewing it indirectly, with peripheral vision. Thus, agnosic vision is like peripheral vision. We obtained 14 visual-object-recognition tests that are commonly used for diagnosis of visual agnosia. Our "standard" normal observer took these tests at various eccentricities in his periphery. Analyzing the published data of 32 apperceptive agnosia patients and a group of 14 posterior cortical atrophy (PCA) patients on these tests, we find that each patient's pattern of object recognition deficits is well characterized by one number, the equivalent eccentricity at which our standard observer's peripheral vision is like the central vision of the agnosic patient. In other words, each agnosic patient's equivalent eccentricity is conserved across tests. Across patients, equivalent eccentricity ranges from 4 to 40 deg, which rates severity of the visual deficit. In normal peripheral vision, the required size to perceive a simple image (e.g., an isolated letter) is limited by acuity, and that for a complex image (e.g., a face or a word) is limited by crowding. In crowding, adjacent simple objects appear unrecognizably jumbled unless their spacing exceeds the crowding distance, which grows linearly with eccentricity. Besides conservation of equivalent eccentricity across object-recognition tests, we also find conservation, from eccentricity to agnosia, of the relative susceptibility of recognition of ten visual tests. These findings show that agnosic vision is like eccentric vision. Whence crowding? Peripheral vision, strabismic amblyopia, and possibly apperceptive agnosia are all limited by crowding, making it

Visual processing in rapid-chase systems: Image processing, attention, and awareness

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Thomas eSchmidt

2011-07-01

Full Text Available Visual stimuli can be classified so rapidly that their analysis may be based on a single sweep of feedforward processing through the visuomotor system. Behavioral criteria for feedforward processing can be evaluated in response priming tasks where speeded pointing or keypress responses are performed towards target stimuli which are preceded by prime stimuli. We apply this method to several classes of complex stimuli. 1 When participants classify natural images into animals or non-animals, the time course of their pointing responses indicates that prime and target signals remain strictly sequential throughout all processing stages, meeting stringent behavioral criteria for feedforward processing (rapid-chase criteria. 2 Such priming effects are boosted by selective visual attention for positions, shapes, and colors, in a way consistent with bottom-up enhancement of visuomotor processing, even when primes cannot be consciously identified. 3 Speeded processing of phobic images is observed in participants specifically fearful of spiders or snakes, suggesting enhancement of feedforward processing by long-term perceptual learning. 4 When the perceived brightness of primes in complex displays is altered by means of illumination or transparency illusions, priming effects in speeded keypress responses can systematically contradict subjective brightness judgments, such that one prime appears brighter than the other but activates motor responses as if it was darker. We propose that response priming captures the output of the first feedforward pass of visual signals through the visuomotor system, and that this output lacks some characteristic features of more elaborate, recurrent processing. This way, visuomotor measures may become dissociated from several aspects of conscious vision. We argue that "fast" visuomotor measures predominantly driven by feedforward processing should supplement "slow" psychophysical measures predominantly based on visual

Embedded active vision system based on an FPGA architecture

OpenAIRE

Chalimbaud , Pierre; Berry , François

2006-01-01

International audience; In computer vision and more particularly in vision processing, the impressive evolution of algorithms and the emergence of new techniques dramatically increase algorithm complexity. In this paper, a novel FPGA-based architecture dedicated to active vision (and more precisely early vision) is proposed. Active vision appears as an alternative approach to deal with artificial vision problems. The central idea is to take into account the perceptual aspects of visual tasks,...

Acting without seeing: eye movements reveal visual processing without awareness.

Science.gov (United States)

Spering, Miriam; Carrasco, Marisa

2015-04-01

Visual perception and eye movements are considered to be tightly linked. Diverse fields, ranging from developmental psychology to computer science, utilize eye tracking to measure visual perception. However, this prevailing view has been challenged by recent behavioral studies. Here, we review converging evidence revealing dissociations between the contents of perceptual awareness and different types of eye movement. Such dissociations reveal situations in which eye movements are sensitive to particular visual features that fail to modulate perceptual reports. We also discuss neurophysiological, neuroimaging, and clinical studies supporting the role of subcortical pathways for visual processing without awareness. Our review links awareness to perceptual-eye movement dissociations and furthers our understanding of the brain pathways underlying vision and movement with and without awareness. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spatial contrast sensitivity vision loss in children with cortical visual impairment.

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Good, William V; Hou, Chuan; Norcia, Anthony M

2012-11-19

Although cortical visual impairment (CVI) is the leading cause of bilateral vision impairment in children in Western countries, little is known about the effects of CVI on visual function. The aim of this study was to compare visual evoked potential measures of contrast sensitivity and grating acuity in children with CVI with those of age-matched typically developing controls. The swept parameter visual evoked potential (sVEP) was used to measure contrast sensitivity and grating acuity in 34 children with CVI at 5 months to 5 years of age and in 16 age-matched control children. Contrast thresholds and spatial frequency thresholds (grating acuities) were derived by extrapolating the tuning functions to zero amplitude. These thresholds and maximal suprathreshold response amplitudes were compared between groups. Among 34 children with CVI, 30 had measurable but reduced contrast sensitivity with a median threshold of 10.8% (range 5.0%-30.0% Michelson), and 32 had measurable but reduced grating acuity with median threshold 0.49 logMAR (9.8 c/deg, range 5-14 c/deg). These thresholds were significantly reduced, compared with age-matched control children. In addition, response amplitudes over the entire sweep range for both measures were significantly diminished in children with CVI compared with those of control children. Our results indicate that spatial contrast sensitivity and response amplitudes are strongly affected by CVI. The substantial degree of loss in contrast sensitivity suggests that contrast is a sensitive measure for evaluating vision deficits in patients with CVI.

Understanding of how older adults with low vision obtain, process, and understand health information and services.

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Kim, Hyung Nam

2017-10-16

Twenty-five years after the Americans with Disabilities Act, there has still been a lack of advancement of accessibility in healthcare for people with visual impairments, particularly older adults with low vision. This study aims to advance understanding of how older adults with low vision obtain, process, and use health information and services, and to seek opportunities of information technology to support them. A convenience sample of 10 older adults with low vision participated in semi-structured phone interviews, which were audio-recorded and transcribed verbatim for analysis. Participants shared various concerns in accessing, understanding, and using health information, care services, and multimedia technologies. Two main themes and nine subthemes emerged from the analysis. Due to the concerns, older adults with low vision tended to fail to obtain the full range of all health information and services to meet their specific needs. Those with low vision still rely on residual vision such that multimedia-based information which can be useful, but it should still be designed to ensure its accessibility, usability, and understandability.

The Bayley-III accommodated for motor and/or visual impairment : “Low motor/vision version”.

NARCIS (Netherlands)

Visser, Linda; Ruiter, Selma; Timmerman, Marieke; van der Meulen, Bieuwe; Ruijssenaars, Wied

Introduction: The aim of the newly developed Low Motor/Vision (LM/LVi) version of the Dutch Bayley-III is to increase the suitability of the instrument for testing children with a motor and/or visual impairment. Method: We tested 64 children with motor and/or visual impairment with the Low

Do visually impaired children and their parents agree on the child's vision-related quality of life and functional vision?

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Tadić, Valerija; Cumberland, Phillippa M; Lewando-Hundt, Gillian; Rahi, Jugnoo S

2017-01-01

Aims To investigate agreement between children with visual impairment (VI) and their parents on their ratings of the child's vision-related quality of life (VQoL) and functional vision (FV) using two novel self-report patient-reported outcome measures developed for this population. Methods 99 children aged 10–15 years (mean age=12.2, SD=1.9) with VI (best corrected acuity (logarithm of the minimum angle of resolution) 0.50 or worse in better eye) and their parents participated in a national postal survey, completing the child and proxy versions of our novel instruments assessing VQoL and FV of children with VI—the vision-related quality of life instrument for children and young people (VQoL_CYP) and the functional vision questionnaire for children and young people (FVQ_CYP), respectively. Parent-child agreement was investigated using the Bland-Altman (BA) method. Variation across key sociodemographic and clinical characteristics was examined using the Intraclass Correlation Coefficient. Results Average parental ratings of their child's VQoL and FV were significantly lower than the children's own ratings, but the range of disagreement was wide, with parents both overestimating and underestimating their child's VQoL (mean score difference=5.7, BA limits of agreement (LOA): lower −22.10 (CI 95% −24.61 to 19.59) and upper 33.50 (CI 95% 30.99 to 36.01)), but more consistently underestimating the child's FV (mean score difference=−11.8, BA LOA: lower −39.60 (CI 95% −42.12 to 37.08) and upper 16 (CI 95% 13.48 to 18.52)). There was variation in agreement by some child characteristics, including vision level, time of onset and course of VI progression. Conclusions Visually impaired children and their parents perceive the broader impact of living with VI very differently. There is value in routine capture of information independently from children and their parents for comprehensively gauging the impact of childhood VI and tailoring appropriate interventions

The Influence of Manifest Strabismus and Stereoscopic Vision on Non-Verbal Abilities of Visually Impaired Children

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Gligorovic, Milica; Vucinic, Vesna; Eskirovic, Branka; Jablan, Branka

2011-01-01

This research was conducted in order to examine the influence of manifest strabismus and stereoscopic vision on non-verbal abilities of visually impaired children aged between 7 and 15. The sample included 55 visually impaired children from the 1st to the 6th grade of elementary schools for visually impaired children in Belgrade. RANDOT stereotest…

Reinforcement learning in computer vision

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Bernstein, A. V.; Burnaev, E. V.

2018-04-01

Nowadays, machine learning has become one of the basic technologies used in solving various computer vision tasks such as feature detection, image segmentation, object recognition and tracking. In many applications, various complex systems such as robots are equipped with visual sensors from which they learn state of surrounding environment by solving corresponding computer vision tasks. Solutions of these tasks are used for making decisions about possible future actions. It is not surprising that when solving computer vision tasks we should take into account special aspects of their subsequent application in model-based predictive control. Reinforcement learning is one of modern machine learning technologies in which learning is carried out through interaction with the environment. In recent years, Reinforcement learning has been used both for solving such applied tasks as processing and analysis of visual information, and for solving specific computer vision problems such as filtering, extracting image features, localizing objects in scenes, and many others. The paper describes shortly the Reinforcement learning technology and its use for solving computer vision problems.

Low Vision FAQs

Science.gov (United States)

... de los Ojos Cómo hablarle a su oculista Low Vision FAQs What is low vision? Low vision is a visual impairment, not correctable ... person’s ability to perform everyday activities. What causes low vision? Low vision can result from a variety of ...

Visual information processing II; Proceedings of the Meeting, Orlando, FL, Apr. 14-16, 1993

Science.gov (United States)

Huck, Friedrich O. (Editor); Juday, Richard D. (Editor)

1993-01-01

Various papers on visual information processing are presented. Individual topics addressed include: aliasing as noise, satellite image processing using a hammering neural network, edge-detetion method using visual perception, adaptive vector median filters, design of a reading test for low-vision image warping, spatial transformation architectures, automatic image-enhancement method, redundancy reduction in image coding, lossless gray-scale image compression by predictive GDF, information efficiency in visual communication, optimizing JPEG quantization matrices for different applications, use of forward error correction to maintain image fidelity, effect of peanoscanning on image compression. Also discussed are: computer vision for autonomous robotics in space, optical processor for zero-crossing edge detection, fractal-based image edge detection, simulation of the neon spreading effect by bandpass filtering, wavelet transform (WT) on parallel SIMD architectures, nonseparable 2D wavelet image representation, adaptive image halftoning based on WT, wavelet analysis of global warming, use of the WT for signal detection, perfect reconstruction two-channel rational filter banks, N-wavelet coding for pattern classification, simulation of image of natural objects, number-theoretic coding for iconic systems.

Efficacy of a Low Vision Patient Consultation

Science.gov (United States)

Siemsen, Dennis W.; Bergstrom, A. Ren?e; Hathaway, Julie C.

2005-01-01

A variety of obstacles can prevent persons or individuals with low vision from deriving the greatest possible benefit from the rehabilitation process, including inadequate understanding of their visual impairment, lack of knowledge about available services, and misconceptions about low vision devices. This study explores the use of a…

Perception of linear horizontal self-motion induced by peripheral vision /linearvection/ - Basic characteristics and visual-vestibular interactions

Science.gov (United States)

Berthoz, A.; Pavard, B.; Young, L. R.

1975-01-01

The basic characteristics of the sensation of linear horizontal motion have been studied. Objective linear motion was induced by means of a moving cart. Visually induced linear motion perception (linearvection) was obtained by projection of moving images at the periphery of the visual field. Image velocity and luminance thresholds for the appearance of linearvection have been measured and are in the range of those for image motion detection (without sensation of self motion) by the visual system. Latencies of onset are around 1 sec and short term adaptation has been shown. The dynamic range of the visual analyzer as judged by frequency analysis is lower than the vestibular analyzer. Conflicting situations in which visual cues contradict vestibular and other proprioceptive cues show, in the case of linearvection a dominance of vision which supports the idea of an essential although not independent role of vision in self motion perception.

Color Functionality Used in Visual Display for Occupational and Environmental Safety and Managing Color Vision Deficiency.

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Ochiai, Nobuhisa; Kondo, Hiroyuki

2017-01-01

The effects of color perception are utilized in visual displays for the purpose of safety in the workplace and in daily life. These effects, generally known as color functionality, are divided into four classifications: visibility, legibility, conspicuity and discriminability. This article focuses on the relationship between the color functionality of color schemes used in visual displays for occupational and environmental safety and color vision deficiency (particularly congenital red-green color deficiency), a critical issue in ophthalmology, and examines the effects of color functionality on the perception of the color red in individuals with protan defects. Due to abrupt system reforms, current Japanese clinical ophthalmology finds itself in a situation where it is insufficiently prepared to handle congenital red-green color deficiencies. Indeed, occupational problems caused by color vision deficiencies have been almost completely neglected, and are an occupational safety and health concern that will need to be solved in the future. This report will present the guidelines for the color vision testing established by the British Health and Safety Executive (HSE), a pioneering example of a model meant to solve these problems. Issues relating to the creation of guidelines adapted to Japanese clinical ophthalmology will also be examined, and we will discuss ways to utilize color functionality used in visual displays for occupational and environmental safety to help manage color vision deficiency.

Visual Enhancement for Sports Entertainment by Vision-Based Augmented Reality

OpenAIRE

Uematsu, Yuko; Saito, Hideo

2008-01-01

This paper presents visually enhanced sports entertainment applications: AR Baseball Presentation System and Interactive AR Bowling System. We utilize vision-based augmented reality for getting immersive feeling. First application is an observation system of a virtual baseball game on the tabletop. 3D virtual players are playing a game on a real baseball field model, so that users can observe the game from favorite view points through a handheld monitor with a web camera....

Visual cues in low-level flight - Implications for pilotage, training, simulation, and enhanced/synthetic vision systems

Science.gov (United States)

Foyle, David C.; Kaiser, Mary K.; Johnson, Walter W.

1992-01-01

This paper reviews some of the sources of visual information that are available in the out-the-window scene and describes how these visual cues are important for routine pilotage and training, as well as the development of simulator visual systems and enhanced or synthetic vision systems for aircraft cockpits. It is shown how these visual cues may change or disappear under environmental or sensor conditions, and how the visual scene can be augmented by advanced displays to capitalize on the pilot's excellent ability to extract visual information from the visual scene.

Comparison of visual outcomes after bilateral implantation of extended range of vision and trifocal intraocular lenses.

Science.gov (United States)

Ruiz-Mesa, Ramón; Abengózar-Vela, Antonio; Aramburu, Ana; Ruiz-Santos, María

2017-06-26

To compare visual outcomes after cataract surgery with bilateral implantation of 2 intraocular lenses (IOLs): extended range of vision and trifocal. Each group of this prospective study comprised 40 eyes (20 patients). Phacoemulsification followed by bilateral implantation of a FineVision IOL (group 1) or a Symfony IOL (group 2) was performed. The following outcomes were assessed up to 1 year postoperatively: binocular uncorrected distance visual acuity (UDVA), binocular uncorrected intermediate visual acuity (UIVA) at 60 cm, binocular uncorrected near visual acuity (UNVA) at 40 cm, spherical equivalent (SE) refraction, defocus curves, mesopic and photopic contrast sensitivity, halometry, posterior capsule opacification (PCO), and responses to a patient questionnaire. The mean binocular values in group 1 and group 2, respectively, were SE -0.15 ± 0.25 D and -0.19 ± 0.18 D; UDVA 0.01 ± 0.03 logMAR and 0.01 ± 0.02 logMAR; UIVA 0.11 ± 0.08 logMAR and 0.09 ± 0.08 logMAR; UNVA 0.06 ± 0.07 logMAR and 0.17 ± 0.06 logMAR. Difference in UNVA between IOLs (pvisual outcomes. The FineVision IOL showed better near visual acuity. Predictability of the refractive results and optical performance were excellent; all patients achieved spectacle independence. The 2 IOLs gave similar and good contrast sensitivity in photopic and mesopic conditions and low perception of halos by patients.

Learning from vision-to-touch is different than from touch-to-vision.

Directory of Open Access Journals (Sweden)

Dagmar A Wismeijer

2012-11-01

Full Text Available We studied whether vision can teach touch to the same extent as touch seems to teach vision. In a 2 x 2 between-participants learning study, we artificially correlated visual gloss cues with haptic compliance cues. In two "natural" tasks, we tested whether visual gloss estimations have an influence on haptic estimations of softness and vice versa. In two "new" tasks, in which participants were either asked to haptically judge glossiness or to visually judge softness, we investigated how perceptual estimates transfer from one sense to the other. Our results showed that vision does not teach touch as efficient as touch seems to teach vision.

Crowded visual search in children with normal vision and children with visual impairment.

Science.gov (United States)

Huurneman, Bianca; Cox, Ralf F A; Vlaskamp, Björn N S; Boonstra, F Nienke

2014-03-01

This study investigates the influence of oculomotor control, crowding, and attentional factors on visual search in children with normal vision ([NV], n=11), children with visual impairment without nystagmus ([VI-nys], n=11), and children with VI with accompanying nystagmus ([VI+nys], n=26). Exclusion criteria for children with VI were: multiple impairments and visual acuity poorer than 20/400 or better than 20/50. Three search conditions were presented: a row with homogeneous distractors, a matrix with homogeneous distractors, and a matrix with heterogeneous distractors. Element spacing was manipulated in 5 steps from 2 to 32 minutes of arc. Symbols were sized 2 times the threshold acuity to guarantee visibility for the VI groups. During simple row and matrix search with homogeneous distractors children in the VI+nys group were less accurate than children with NV at smaller spacings. Group differences were even more pronounced during matrix search with heterogeneous distractors. Search times were longer in children with VI compared to children with NV. The more extended impairments during serial search reveal greater dependence on oculomotor control during serial compared to parallel search. Copyright © 2014 Elsevier B.V. All rights reserved.

From elements to perception: local and global processing in visual neurons.

Science.gov (United States)

Spillmann, L

1999-01-01

Gestalt psychologists in the early part of the century challenged psychophysical notions that perceptual phenomena can be understood from a punctate (atomistic) analysis of the elements present in the stimulus. Their ideas slowed later attempts to explain vision in terms of single-cell recordings from individual neurons. A rapprochement between Gestalt phenomenology and neurophysiology seemed unlikely when the first ECVP was held in Marburg, Germany, in 1978. Since that time, response properties of neurons have been discovered that invite an interpretation of visual phenomena (including illusions) in terms of neuronal processing by long-range interactions, as first proposed by Mach and Hering in the last century. This article traces a personal journey into the early days of neurophysiological vision research to illustrate the progress that has taken place from the first attempts to correlate single-cell responses with visual perceptions. Whereas initially the receptive-field properties of individual classes of cells--e.g., contrast, wavelength, orientation, motion, disparity, and spatial-frequency detectors--were used to account for relatively simple visual phenomena, nowadays complex perceptions are interpreted in terms of long-range interactions, involving many neurons. This change in paradigm from local to global processing was made possible by recent findings, in the cortex, on horizontal interactions and backward propagation (feedback loops) in addition to classical feedforward processing. These mechanisms are exemplified by studies of the tilt effect and tilt aftereffect, direction-specific motion adaptation, illusory contours, filling-in and fading, figure--ground segregation by orientation and motion contrast, and pop-out in dynamic visual-noise patterns. Major questions for future research and a discussion of their epistemological implications conclude the article.

The vision guidance and image processing of AGV

Science.gov (United States)

Feng, Tongqing; Jiao, Bin

2017-08-01

Firstly, the principle of AGV vision guidance is introduced and the deviation and deflection angle are measured by image coordinate system. The visual guidance image processing platform is introduced. In view of the fact that the AGV guidance image contains more noise, the image has already been smoothed by a statistical sorting. By using AGV sampling way to obtain image guidance, because the image has the best and different threshold segmentation points. In view of this situation, the method of two-dimensional maximum entropy image segmentation is used to solve the problem. We extract the foreground image in the target band by calculating the contour area method and obtain the centre line with the least square fitting algorithm. With the help of image and physical coordinates, we can obtain the guidance information.

A proposed intracortical visual prosthesis image processing system.

Science.gov (United States)

Srivastava, N R; Troyk, P

2005-01-01

It has been a goal of neuroprosthesis researchers to develop a system, which could provide artifical vision to a large population of individuals with blindness. It has been demonstrated by earlier researches that stimulating the visual cortex area electrically can evoke spatial visual percepts, i.e. phosphenes. The goal of visual cortex prosthesis is to stimulate the visual cortex area and generate a visual perception in real time to restore vision. Even though the normal working of the visual system is not been completely understood, the existing knowledge has inspired research groups to develop strategies to develop visual cortex prosthesis which can help blind patients in their daily activities. A major limitation in this work is the development of an image proceessing system for converting an electronic image, as captured by a camera, into a real-time data stream for stimulation of the implanted electrodes. This paper proposes a system, which will capture the image using a camera and use a dedicated hardware real time image processor to deliver electrical pulses to intracortical electrodes. This system has to be flexible enough to adapt to individual patients and to various strategies of image reconstruction. Here we consider a preliminary architecture for this system.

The effects of sports vision exercises on the visual skills of university ...

African Journals Online (AJOL)

This study aims to determine if sports vision exercises could improve visual skills and thereby enhance motor and cognitive performance. A 169 second year physiology students (18-22 years of age) participated in the study. The students were divided into control (n=78) and experimental groups (n=91) and pre and post ...

Relationship between Vision and Visual Perception in Hong Kong Preschoolers.

Science.gov (United States)

Ho, Wing-Cheung; Tang, Minny Mei-Miu; Fu, Ching-Wah; Leung, Ka-Yan; Pang, Peter Chi-Kong; Cheong, Allen Ming-Yan

2015-05-01

Although superior performance in visual motor and visual perceptual skills of preschool children has been documented in the Chinese population, a normative database is only available for the US population. This study aimed to determine the normative values for these visuomotor and visual perceptual tests for preschool children in the Hong Kong Chinese population and to investigate the effect of fundamental visual functions on visuomotor and visual perceptual skills. One hundred seventy-four children from six different kindergartens in Hong Kong were recruited. Distance visual acuity, near visual acuity, and stereopsis were tested, along with two measures of visual perception (VP): Visual-Motor Integration (VMI) and Test of Visual-Perceptual Skills (TVPS). Raw VMI and TVPS scores were converted into standard/scaled scores. The impact of basic visual functions on VP (VMI and TVPS) was examined using multiple regression. Visual functions were generally good: only 9.2 and 4.6% of subjects had unilateral and bilateral reduced habitual vision, respectively (distance visual acuity in the better eye >0.3 logMAR [logarithm of the minimum angle of resolution]). Performance in the VMI and in the visual memory and spatial relationships subtests of the TVPS exceeded that reported for age-matched children from the United States. Multiple regression analysis provided evidence that age had the strongest predictive value for the VMI and VP skills. In addition, near visual acuity was weakly associated with performance in the VMI and the visual discrimination and spatial relationships subtests of the TVPS, accounting for a limited proportion of the intersubject variability (R memory/spatial relationships of TVPS subtests, perhaps attributed to greater exposure to such material during their preschool home education. This study provided normality data for VMI and four subtests of the TVPS for Hong Kong Chinese preschool children as a reference for future studies.

A digital retina-like low-level vision processor.

Science.gov (United States)

Mertoguno, S; Bourbakis, N G

2003-01-01

This correspondence presents the basic design and the simulation of a low level multilayer vision processor that emulates to some degree the functional behavior of a human retina. This retina-like multilayer processor is the lower part of an autonomous self-organized vision system, called Kydon, that could be used on visually impaired people with a damaged visual cerebral cortex. The Kydon vision system, however, is not presented in this paper. The retina-like processor consists of four major layers, where each of them is an array processor based on hexagonal, autonomous processing elements that perform a certain set of low level vision tasks, such as smoothing and light adaptation, edge detection, segmentation, line recognition and region-graph generation. At each layer, the array processor is a 2D array of k/spl times/m hexagonal identical autonomous cells that simultaneously execute certain low level vision tasks. Thus, the hardware design and the simulation at the transistor level of the processing elements (PEs) of the retina-like processor and its simulated functionality with illustrative examples are provided in this paper.

Living with vision loss

Science.gov (United States)

Diabetes - vision loss; Retinopathy - vision loss; Low vision; Blindness - vision loss ... of visual aids. Some options include: Magnifiers High power reading glasses Devices that make it easier to ...

Visual Prosthesis: Interfacing Stimulating Electrodes with Retinal Neurons to Restore Vision

Directory of Open Access Journals (Sweden)

Alejandro Barriga-Rivera

2017-11-01

Full Text Available The bypassing of degenerated photoreceptors using retinal neurostimulators is helping the blind to recover functional vision. Researchers are investigating new ways to improve visual percepts elicited by these means as the vision produced by these early devices remain rudimentary. However, several factors are hampering the progression of bionic technologies: the charge injection limits of metallic electrodes, the mechanical mismatch between excitable tissue and the stimulating elements, neural and electric crosstalk, the physical size of the implanted devices, and the inability to selectively activate different types of retinal neurons. Electrochemical and mechanical limitations are being addressed by the application of electromaterials such as conducting polymers, carbon nanotubes and nanocrystalline diamonds, among other biomaterials, to electrical neuromodulation. In addition, the use of synthetic hydrogels and cell-laden biomaterials is promising better interfaces, as it opens a door to establishing synaptic connections between the electrode material and the excitable cells. Finally, new electrostimulation approaches relying on the use of high-frequency stimulation and field overlapping techniques are being developed to better replicate the neural code of the retina. All these elements combined will bring bionic vision beyond its present state and into the realm of a viable, mainstream therapy for vision loss.

Efficacy of perceptual vision therapy in enhancing visual acuity and contrast sensitivity function in adult hypermetropic anisometropic amblyopia

Directory of Open Access Journals (Sweden)

Yalcin E

2013-12-01

Full Text Available Elvan Yalcin, Ozlem BalciWorld Eye Hospital, Department of Pediatric Ophthalmology, Istanbul, TurkeyBackground: The purpose of this study was to evaluate the efficacy of neural vision therapy, also termed perceptual vision therapy, in enhancing best corrected visual acuity (BCVA and contrast sensitivity function in amblyopic patients.Methods: This prospective study enrolled 99 subjects previously diagnosed with unilateral hypermetropic amblyopia aged 9–50 years. The subjects were divided into two groups, with 53 subjects (53 eyes in the perceptual vision therapy group and 46 subjects (46 eyes in the control group. Because the nature of the treatment demands hard work and strict compliance, we enrolled the minimal number of subjects required to achieve statistically significant results. Informed consent was obtained from all subjects. Study phases included a baseline screening, a series of 45 training sessions with perceptual vision therapy, and an end-of-treatment examination. BCVA and contrast sensitivity function at 1.5, 3, 6, 12, and 18 cycles per degree spatial frequencies were obtained for statistical analysis in both groups. All subjects had follow-up examinations within 4–8 months. With the exception of one subject from the study group and two subjects from the control group, all subjects had occlusion during childhood. The study was not masked.Results: The results for the study group demonstrated a mean improvement of 2.6 logarithm of the minimum angle of resolution (logMAR lines in visual acuity (from 0.42 to 0.16 logMAR. Contrast sensitivity function improved at 1.5, 3, 6, 12, and 18 cycles per degree spatial frequencies. The control group did not show any significant change in visual acuity or contrast sensitivity function. None of the treated eyes showed a drop in visual acuity. Manifest refractions remained unchanged during the study.Conclusion: The results of our study demonstrate the efficacy of perceptual vision therapy in

Braille Reading Accuracy of Students Who Are Visually Impaired: The Effects of Gender, Age at Vision Loss, and Level of Education

Science.gov (United States)

Argyropoulos, Vassilis; Papadimitriou, Vassilios

2015-01-01

Introduction: The present study assesses the performance of students who are visually impaired (that is, those who are blind or have low vision) in braille reading accuracy and examines potential correlations among the error categories on the basis of gender, age at loss of vision, and level of education. Methods: Twenty-one visually impaired…

Procedures and Tools Used by Teachers When Completing Functional Vision Assessments with Children with Visual Impairments

Science.gov (United States)

Kaiser, Justin T.; Herzberg, Tina S.

2017-01-01

Introduction: This study analyzed survey responses from 314 teachers of students with visual impairments regarding the tools and procedures used in completing functional vision assessments (FVAs). Methods: Teachers of students with visual impairments in the United States and Canada completed an online survey during spring 2016. Results: The…

Key Features of the Manufacturing Vision Development Process

DEFF Research Database (Denmark)

Dukovska-Popovska, Iskra; Riis, Jens Ove; Boer, Harry

2005-01-01

of action research. The methodology recommends wide participation of people from different hierarchical and functional positions, who engage in a relatively short, playful and creative process and come up with a vision (concept) for the future manufacturing system in the company. Based on three case studies......This paper discusses the key features of the process of Manufacturing Vision Development, a process that enables companies to develop their future manufacturing concept. The basis for the process is a generic five-phase methodology (Riis and Johansen 2003) developed as a result of ten years...... of companies going through the initial phases of the methodology, this research identified the key features of the Manufacturing Vision Development process. The paper elaborates the key features by defining them, discussing how and when they can appear, and how they influence the process....

The impact of cataract surgery on visual functioning, vision-related disability and psychological distress: a randomized controlled trial.

Science.gov (United States)

Walker, Janine G; Anstey, Kaarin J; Hennessy, Michael P; Lord, Stephen R; von Sanden, Chwee

2006-11-01

Determine whether there are changes in visual functioning, vision-related disability, health status and mood after cataract surgery. 45 adults (mean age = 73.7 years) with bilateral cataract needing surgery for the first eye were recruited from public ophthalmology clinics. The Visual Functioning-14 survey assessed visual disability. Minimal angle of resolution tested visual acuity, and the Melbourne Edge Test examined contrast sensitivity. Demographic, psychological, health and medication use variables were examined. Participants were randomized to either an intervention or control arm. Controls were assessed on two occasions at a 3-month interval before having surgery. The intervention group was assessed 1-2 weeks before surgery and then reassessed 3 months after surgery. Visual functioning improved for those who had cataract surgery with better visual acuity in the better (P = 0.010) and worse (P = 0.028) eye compared with controls. The intervention group reported fewer difficulties with overall vision-related disability (P = 0.0001), reading (P = 0.004) and instrumental activities of daily living (P = 0.010) post-surgery compared with controls. People with improved depression scores (P = 0.048) after surgery had less difficulty with reading compared with those with unchanged or worsened depression scores. Cataract surgery did not improve health status. First eye cataract surgery is effective in improving outcomes in visual functioning and disability. Improved mood after surgery was related to less vision-related disability compared with unchanged or worse depression.

Early vision and visual attention

OpenAIRE

Gvozdenović Vasilije P.

2003-01-01

The question whether visual perception is spontaneous, sudden or is running through several phases, mediated by higher cognitive processes, was raised ever since the early work of Gestalt psychologists. In the early 1980s, Treisman proposed the feature integration theory of attention (FIT), based on the findings of neuroscience. Soon after publishing her theory a new scientific approach appeared investigating several visual perception phenomena. The most widely researched were the key constru...

Impact of low vision services on the quality of life of low vision patients in Ghana

Directory of Open Access Journals (Sweden)

Godwin O. Ovenseri-Ogbomo

2016-03-01

Full Text Available Patients’ perspectives on the impact of clinical interventions have been recognised as critical elements in patient care. Quality-of-life instruments are designed to measure these perspectives. We used the National Eye Institute’s 25-item Visual Function Questionnaire (NEI VFQ to measure the impact of optical low vision devices on the quality of life of 22 low vision patients who obtained and were using low vision devices from a secondary low vision clinic in the Eastern Region, Ghana. The study employed a pre- and post-intervention technique. We found statistically significant improvements in measured visual acuity and NEI VFQ scores in 8 of the 10 domains evaluated. We conclude that optical low vision devices have a positive impact on the quality of life of low vision patients in Ghana. Keywords: low vision; quality of life; visual acuity; visual impairment; Ghana

Case Report: Use of Sports and Performance Vision Training to Benefit a Low-vision Patient's Function.

Science.gov (United States)

Laby, Daniel M

2018-05-17

Despite our inability to attenuate the course of many ocular diseases that can ultimately lead to loss or significantly decreased visual function, this report describes a potential technique to aid such patients in maximizing the use of the vision that remains. The aim of this study was to demonstrate the applicability of utilizing sports vision training to improve objective and subjective visuomotor function in a low-vision patient. A 37-year-old woman with Usher syndrome presented with reduced central visual acuity and visual field. Although we were unable to reverse the damage resulting from her diagnosis, we were able to improve the use of the remaining vision. A 27 to 31% improvement in hand-eye coordination was achieved along with a 41% improvement in object tracking and visual concentration. Most importantly, following the 14-week training period, there was also a subjective improvement in the patient's appreciation of her visual ability. The sports vision literature cites many examples in which sports vision training is useful in improving visuomotor and on-field performance. We hypothesized that these techniques may be used to aid not only athletes but also patients with low vision. Despite suffering from reduced acuity and a limited visual field, these patients often still have a significant amount of vision ability that can be used to guide motor actions. Using techniques to increase the efficient use of this remaining vision may reduce the impact of the reduced visual function and aid in activities of daily living.

Identifying the computational requirements of an integrated top-down-bottom-up model for overt visual attention within an active vision system.

Science.gov (United States)

McBride, Sebastian; Huelse, Martin; Lee, Mark

2013-01-01

Computational visual attention systems have been constructed in order for robots and other devices to detect and locate regions of interest in their visual world. Such systems often attempt to take account of what is known of the human visual system and employ concepts, such as 'active vision', to gain various perceived advantages. However, despite the potential for gaining insights from such experiments, the computational requirements for visual attention processing are often not clearly presented from a biological perspective. This was the primary objective of this study, attained through two specific phases of investigation: 1) conceptual modeling of a top-down-bottom-up framework through critical analysis of the psychophysical and neurophysiological literature, 2) implementation and validation of the model into robotic hardware (as a representative of an active vision system). Seven computational requirements were identified: 1) transformation of retinotopic to egocentric mappings, 2) spatial memory for the purposes of medium-term inhibition of return, 3) synchronization of 'where' and 'what' information from the two visual streams, 4) convergence of top-down and bottom-up information to a centralized point of information processing, 5) a threshold function to elicit saccade action, 6) a function to represent task relevance as a ratio of excitation and inhibition, and 7) derivation of excitation and inhibition values from object-associated feature classes. The model provides further insight into the nature of data representation and transfer between brain regions associated with the vertebrate 'active' visual attention system. In particular, the model lends strong support to the functional role of the lateral intraparietal region of the brain as a primary area of information consolidation that directs putative action through the use of a 'priority map'.

Artificial vision support system (AVS(2)) for improved prosthetic vision.

Science.gov (United States)

Fink, Wolfgang; Tarbell, Mark A

2014-11-01

State-of-the-art and upcoming camera-driven, implanted artificial vision systems provide only tens to hundreds of electrodes, affording only limited visual perception for blind subjects. Therefore, real time image processing is crucial to enhance and optimize this limited perception. Since tens or hundreds of pixels/electrodes allow only for a very crude approximation of the typically megapixel optical resolution of the external camera image feed, the preservation and enhancement of contrast differences and transitions, such as edges, are especially important compared to picture details such as object texture. An Artificial Vision Support System (AVS(2)) is devised that displays the captured video stream in a pixelation conforming to the dimension of the epi-retinal implant electrode array. AVS(2), using efficient image processing modules, modifies the captured video stream in real time, enhancing 'present but hidden' objects to overcome inadequacies or extremes in the camera imagery. As a result, visual prosthesis carriers may now be able to discern such objects in their 'field-of-view', thus enabling mobility in environments that would otherwise be too hazardous to navigate. The image processing modules can be engaged repeatedly in a user-defined order, which is a unique capability. AVS(2) is directly applicable to any artificial vision system that is based on an imaging modality (video, infrared, sound, ultrasound, microwave, radar, etc.) as the first step in the stimulation/processing cascade, such as: retinal implants (i.e. epi-retinal, sub-retinal, suprachoroidal), optic nerve implants, cortical implants, electric tongue stimulators, or tactile stimulators.

Visual rehabilitation with Retimax Vision Trainer in patients with severe Acquired Brain Injury: report of two cases

Directory of Open Access Journals (Sweden)

Margherita Chiari

2014-04-01

Full Text Available Retimax Vision Trainer is a device that has the purpose to improve visual function by means of the detection of a visual evoked potential associated with a sound feedback. We evaluated the effectiveness of rehabilitative treatment in two patients with Acquired Brain Injury (ABI. Results, subjectively appreciated, are objectively confirmed by the improvement of visual function.

Learning from vision-to-touch is different than learning from touch-to-vision.

Science.gov (United States)

Wismeijer, Dagmar A; Gegenfurtner, Karl R; Drewing, Knut

2012-01-01

We studied whether vision can teach touch to the same extent as touch seems to teach vision. In a 2 × 2 between-participants learning study, we artificially correlated visual gloss cues with haptic compliance cues. In two "natural" tasks, we tested whether visual gloss estimations have an influence on haptic estimations of softness and vice versa. In two "novel" tasks, in which participants were either asked to haptically judge glossiness or to visually judge softness, we investigated how perceptual estimates transfer from one sense to the other. Our results showed that vision does not teach touch as efficient as touch seems to teach vision.

Manufacturing Vision Development – Process and Dialogue

DEFF Research Database (Denmark)

Dukovska-Popovska, Iskra

This Ph.D. project has been conducted in the context of PRODUCTION+5 methodology for devel¬oping manufacturing visions for companies, and related to Experimental Laboratory for Production. Both have been established in the Center for Industrial Production. The empirical parts of the research invo...... involve case studies of three companies that are part of the MCD-process. The cases primarily are focusing on the process and the dialogue dur¬ing the manufacturing vision development.......This Ph.D. project has been conducted in the context of PRODUCTION+5 methodology for devel¬oping manufacturing visions for companies, and related to Experimental Laboratory for Production. Both have been established in the Center for Industrial Production. The empirical parts of the research...

Effect of oculomotor vision rehabilitation on the visual-evoked potential and visual attention in mild traumatic brain injury.

Science.gov (United States)

Yadav, Naveen K; Thiagarajan, Preethi; Ciuffreda, Kenneth J

2014-01-01

The purpose of the experiment was to investigate the effect of oculomotor vision rehabilitation (OVR) on the visual-evoked potential (VEP) and visual attention in the mTBI population. Subjects (n = 7) were adults with a history of mild traumatic brain injury (mTBI). Each received 9 hours of OVR over a 6-week period. The effects of OVR on VEP amplitude and latency, the attention-related alpha band (8-13 Hz) power (µV(2)) and the clinical Visual Search and Attention Test (VSAT) were assessed before and after the OVR. After the OVR, the VEP amplitude increased and its variability decreased. There was no change in VEP latency, which was normal. Alpha band power increased, as did the VSAT score, following the OVR. The significant changes in most test parameters suggest that OVR affects the visual system at early visuo-cortical levels, as well as other pathways which are involved in visual attention.

Do visually impaired children and their parents agree on the child's vision-related quality of life and functional vision?

Science.gov (United States)

Tadić, Valerija; Cumberland, Phillippa M; Lewando-Hundt, Gillian; Rahi, Jugnoo S

2017-03-01

To investigate agreement between children with visual impairment (VI) and their parents on their ratings of the child's vision-related quality of life (VQoL) and functional vision (FV) using two novel self-report patient-reported outcome measures developed for this population. 99 children aged 10-15 years (mean age=12.2, SD=1.9) with VI (best corrected acuity (logarithm of the minimum angle of resolution) 0.50 or worse in better eye) and their parents participated in a national postal survey, completing the child and proxy versions of our novel instruments assessing VQoL and FV of children with VI-the vision-related quality of life instrument for children and young people (VQoL_CYP) and the functional vision questionnaire for children and young people (FVQ_CYP), respectively. Parent-child agreement was investigated using the Bland-Altman (BA) method. Variation across key sociodemographic and clinical characteristics was examined using the Intraclass Correlation Coefficient. Average parental ratings of their child's VQoL and FV were significantly lower than the children's own ratings, but the range of disagreement was wide, with parents both overestimating and underestimating their child's VQoL (mean score difference=5.7, BA limits of agreement (LOA): lower -22.10 (CI 95% -24.61 to 19.59) and upper 33.50 (CI 95% 30.99 to 36.01)), but more consistently underestimating the child's FV (mean score difference=-11.8, BA LOA: lower -39.60 (CI 95% -42.12 to 37.08) and upper 16 (CI 95% 13.48 to 18.52)). There was variation in agreement by some child characteristics, including vision level, time of onset and course of VI progression. Visually impaired children and their parents perceive the broader impact of living with VI very differently. There is value in routine capture of information independently from children and their parents for comprehensively gauging the impact of childhood VI and tailoring appropriate interventions. Published by the BMJ Publishing Group Limited

Applications of AI, machine vision and robotics

CERN Document Server

Boyer, Kim; Bunke, H

1995-01-01

This text features a broad array of research efforts in computer vision including low level processing, perceptual organization, object recognition and active vision. The volume's nine papers specifically report on topics such as sensor confidence, low level feature extraction schemes, non-parametric multi-scale curve smoothing, integration of geometric and non-geometric attributes for object recognition, design criteria for a four degree-of-freedom robot head, a real-time vision system based on control of visual attention and a behavior-based active eye vision system. The scope of the book pr

Effects of visual information regarding allocentric processing in haptic parallelity matching.

Science.gov (United States)

Van Mier, Hanneke I

2013-10-01

Research has revealed that haptic perception of parallelity deviates from physical reality. Large and systematic deviations have been found in haptic parallelity matching most likely due to the influence of the hand-centered egocentric reference frame. Providing information that increases the influence of allocentric processing has been shown to improve performance on haptic matching. In this study allocentric processing was stimulated by providing informative vision in haptic matching tasks that were performed using hand- and arm-centered reference frames. Twenty blindfolded participants (ten men, ten women) explored the orientation of a reference bar with the non-dominant hand and subsequently matched (task HP) or mirrored (task HM) its orientation on a test bar with the dominant hand. Visual information was provided by means of informative vision with participants having full view of the test bar, while the reference bar was blocked from their view (task VHP). To decrease the egocentric bias of the hands, participants also performed a visual haptic parallelity drawing task (task VHPD) using an arm-centered reference frame, by drawing the orientation of the reference bar. In all tasks, the distance between and orientation of the bars were manipulated. A significant effect of task was found; performance improved from task HP, to VHP to VHPD, and HM. Significant effects of distance were found in the first three tasks, whereas orientation and gender effects were only significant in tasks HP and VHP. The results showed that stimulating allocentric processing by means of informative vision and reducing the egocentric bias by using an arm-centered reference frame led to most accurate performance on parallelity matching. © 2013 Elsevier B.V. All rights reserved.

Visualizing the influence of the process parameters on the keyhole dimensions in plasma arc welding

International Nuclear Information System (INIS)

Liu, Z M; Wu, C S; Chen, M A

2012-01-01

The keyhole status and its dimensions are critical information determining both the process quality and weld quality in plasma arc welding (PAW). It is of great significance to measure the keyhole shape and size and to correlate them with the main process parameters. In this study, a low-cost vision system is developed to visualize the keyhole at the backside of the test-pieces in PAW. Three stages of keyhole evolution, i.e. initial blind stage (non-penetrated keyhole), unstable stage with momentarily disappeared keyhole and quasi-steady open keyhole stage (fully-penetrated keyhole), are measured in real-time during the PAW tests on stainless steel test-pieces of thickness 8 mm. Based on the captured images of keyhole under different welding conditions, the correlations of the main welding process parameters (welding current, welding speed, plasma gas flow rate) with the keyhole length, width and area are visualized through vision measurement. It lays a solid foundation for implementing keyhole stability control and process optimization in keyhole PAW. (paper)

Autophagy and phagocytosis converge for better vision.

Science.gov (United States)

Ferguson, Thomas A; Green, Douglas R

2014-01-01

The retinal pigment epithelium (RPE) is a single layer of nonregenerating cells essential to homeostasis in the retina and the preservation of vision. While the RPE perform a number of important functions, 2 essential processes are phagocytosis, which removes the most distal tips of the photoreceptors to support disk renewal, and the visual cycle, which maintains the supply of chromophore for regeneration of photo-bleached visual pigments. We recently reported that these processes are linked by a noncanonical form of autophagy termed LC3-associated phagocytosis (LAP) in which components of the autophagy pathway are co-opted by phagocytosis to recover vitamin A in support of optimal vision. Here we summarize these findings.

Visual dysfunction in Parkinson’s disease

Science.gov (United States)

Weil, Rimona S.; Schrag, Anette E.; Warren, Jason D.; Crutch, Sebastian J.; Lees, Andrew J.; Morris, Huw R.

2016-01-01

Patients with Parkinson’s disease have a number of specific visual disturbances. These include changes in colour vision and contrast sensitivity and difficulties with complex visual tasks such as mental rotation and emotion recognition. We review changes in visual function at each stage of visual processing from retinal deficits, including contrast sensitivity and colour vision deficits to higher cortical processing impairments such as object and motion processing and neglect. We consider changes in visual function in patients with common Parkinson’s disease-associated genetic mutations including GBA and LRRK2. We discuss the association between visual deficits and clinical features of Parkinson’s disease such as rapid eye movement sleep behavioural disorder and the postural instability and gait disorder phenotype. We review the link between abnormal visual function and visual hallucinations, considering current models for mechanisms of visual hallucinations. Finally, we discuss the role of visuo-perceptual testing as a biomarker of disease and predictor of dementia in Parkinson’s disease. PMID:27412389

Clinical Tests of Ultra-Low Vision Used to Evaluate Rudimentary Visual Perceptions Enabled by the BrainPort Vision Device.

Science.gov (United States)

Nau, Amy; Bach, Michael; Fisher, Christopher

2013-01-01

We evaluated whether existing ultra-low vision tests are suitable for measuring outcomes using sensory substitution. The BrainPort is a vision assist device coupling a live video feed with an electrotactile tongue display, allowing a user to gain information about their surroundings. We enrolled 30 adult subjects (age range 22-74) divided into two groups. Our blind group included 24 subjects ( n = 16 males and n = 8 females, average age 50) with light perception or worse vision. Our control group consisted of six subjects ( n = 3 males, n = 3 females, average age 43) with healthy ocular status. All subjects performed 11 computer-based psychophysical tests from three programs: Basic Assessment of Light Motion, Basic Assessment of Grating Acuity, and the Freiburg Vision Test as well as a modified Tangent Screen. Assessments were performed at baseline and again using the BrainPort after 15 hours of training. Most tests could be used with the BrainPort. Mean success scores increased for all of our tests except contrast sensitivity. Increases were statistically significant for tests of light perception (8.27 ± 3.95 SE), time resolution (61.4% ± 3.14 SE), light localization (44.57% ± 3.58 SE), grating orientation (70.27% ± 4.64 SE), and white Tumbling E on a black background (2.49 logMAR ± 0.39 SE). Motion tests were limited by BrainPort resolution. Tactile-based sensory substitution devices are amenable to psychophysical assessments of vision, even though traditional visual pathways are circumvented. This study is one of many that will need to be undertaken to achieve a common outcomes infrastructure for the field of artificial vision.

A Vision-Based Self-Calibration Method for Robotic Visual Inspection Systems

Science.gov (United States)

Yin, Shibin; Ren, Yongjie; Zhu, Jigui; Yang, Shourui; Ye, Shenghua

2013-01-01

A vision-based robot self-calibration method is proposed in this paper to evaluate the kinematic parameter errors of a robot using a visual sensor mounted on its end-effector. This approach could be performed in the industrial field without external, expensive apparatus or an elaborate setup. A robot Tool Center Point (TCP) is defined in the structural model of a line-structured laser sensor, and aligned to a reference point fixed in the robot workspace. A mathematical model is established to formulate the misalignment errors with kinematic parameter errors and TCP position errors. Based on the fixed point constraints, the kinematic parameter errors and TCP position errors are identified with an iterative algorithm. Compared to the conventional methods, this proposed method eliminates the need for a robot-based-frame and hand-to-eye calibrations, shortens the error propagation chain, and makes the calibration process more accurate and convenient. A validation experiment is performed on an ABB IRB2400 robot. An optimal configuration on the number and distribution of fixed points in the robot workspace is obtained based on the experimental results. Comparative experiments reveal that there is a significant improvement of the measuring accuracy of the robotic visual inspection system. PMID:24300597

Predictors of vision impairment in Multiple Sclerosis.

Science.gov (United States)

Sanchez-Dalmau, Bernardo; Martinez-Lapiscina, Elena H; Pulido-Valdeolivas, Irene; Zubizarreta, Irati; Llufriu, Sara; Blanco, Yolanda; Sola-Valls, Nuria; Sepulveda, Maria; Guerrero, Ana; Alba, Salut; Andorra, Magi; Camos, Anna; Sanchez-Vela, Laura; Alfonso, Veronica; Saiz, Albert; Villoslada, Pablo

2018-01-01

Visual impairment significantly alters the quality of life of people with Multiple Sclerosis (MS). The objective of this study was to identify predictors (independent variables) of visual outcomes, and to define their relationship with neurological disability and retinal atrophy when assessed by optical coherence tomography (OCT). We performed a cross-sectional analysis of 119 consecutive patients with MS, assessing vision using high contrast visual acuity (LogMar), 2.5% and 1.25% low contrast visual acuity (Sloan charts), and color vision (Hardy-Rand-Rittler plates). Quality of vision is a patient reported outcome based on an individual's unique perception of his or her vision and was assessed with the Visual Functioning Questionnaire-25 (VFQ-25) with the 10 neuro-ophthalmologic items. MS disability was assessed using the expanded disability status scale (EDSS), the MS functional composite (MSFC) and the brief repetitive battery-neuropsychology (BRB-N). Retinal atrophy was assessed using spectral domain OCT, measuring the thickness of the peripapillar retinal nerve fiber layer (pRNFL) and the volume of the ganglion cell plus inner plexiform layer (GCIPL). The vision of patients with MS was impaired, particularly in eyes with prior optic neuritis. Retinal atrophy (pRNFL and GCIPL) was closely associated with impaired low contrast vision and color vision, whereas the volume of the GCIPL showed a trend (p = 0.092) to be associated with quality of vision. Multiple regression analysis revealed that EDSS was an explanatory variable for high contrast vision after stepwise analysis, GCIPL volume for low contrast vision, and GCIPL volume and EDSS for color vision. The explanatory variables for quality of vision were high contrast vision and color vision. In summary, quality of vision in MS depends on the impairment of high contrast visual acuity and color vision due to the disease.

Visual Enhancement for Sports Entertainment by Vision-Based Augmented Reality

Directory of Open Access Journals (Sweden)

Hideo Saito

2008-09-01

Full Text Available This paper presents visually enhanced sports entertainment applications: AR Baseball Presentation System and Interactive AR Bowling System. We utilize vision-based augmented reality for getting immersive feeling. First application is an observation system of a virtual baseball game on the tabletop. 3D virtual players are playing a game on a real baseball field model, so that users can observe the game from favorite view points through a handheld monitor with a web camera. Second application is a bowling system which allows users to roll a real ball down a real bowling lane model on the tabletop and knock down virtual pins. The users watch the virtual pins through the monitor. The lane and the ball are also tracked by vision-based tracking. In those applications, we utilize multiple 2D markers distributed at arbitrary positions and directions. Even though the geometrical relationship among the markers is unknown, we can track the camera in very wide area.

Robot Vision Library

Science.gov (United States)

Howard, Andrew B.; Ansar, Adnan I.; Litwin, Todd E.; Goldberg, Steven B.

2009-01-01

The JPL Robot Vision Library (JPLV) provides real-time robot vision algorithms for developers who are not vision specialists. The package includes algorithms for stereo ranging, visual odometry and unsurveyed camera calibration, and has unique support for very wideangle lenses

Embedded Active Vision System Based on an FPGA Architecture

Directory of Open Access Journals (Sweden)

Chalimbaud Pierre

2007-01-01

Full Text Available In computer vision and more particularly in vision processing, the impressive evolution of algorithms and the emergence of new techniques dramatically increase algorithm complexity. In this paper, a novel FPGA-based architecture dedicated to active vision (and more precisely early vision is proposed. Active vision appears as an alternative approach to deal with artificial vision problems. The central idea is to take into account the perceptual aspects of visual tasks, inspired by biological vision systems. For this reason, we propose an original approach based on a system on programmable chip implemented in an FPGA connected to a CMOS imager and an inertial set. With such a structure based on reprogrammable devices, this system admits a high degree of versatility and allows the implementation of parallel image processing algorithms.

Embedded Active Vision System Based on an FPGA Architecture

Directory of Open Access Journals (Sweden)

Pierre Chalimbaud

2006-12-01

Full Text Available In computer vision and more particularly in vision processing, the impressive evolution of algorithms and the emergence of new techniques dramatically increase algorithm complexity. In this paper, a novel FPGA-based architecture dedicated to active vision (and more precisely early vision is proposed. Active vision appears as an alternative approach to deal with artificial vision problems. The central idea is to take into account the perceptual aspects of visual tasks, inspired by biological vision systems. For this reason, we propose an original approach based on a system on programmable chip implemented in an FPGA connected to a CMOS imager and an inertial set. With such a structure based on reprogrammable devices, this system admits a high degree of versatility and allows the implementation of parallel image processing algorithms.

The Use of Visual Feedback during Signing: Evidence from Signers with Impaired Vision

Science.gov (United States)

Emmorey, Karen; Korpics, Franco; Petronio, Karen

2009-01-01

The role of visual feedback during the production of American Sign Language was investigated by comparing the size of signing space during conversations and narrative monologues for normally sighted signers, signers with tunnel vision due to Usher syndrome, and functionally blind signers. The interlocutor for all groups was a normally sighted deaf…

Changes in Quality of Life in Visually Impaired Patients after Low-Vision Rehabilitation

Science.gov (United States)

Renieri, Giulia; Pitz, Susanne; Pfeiffer, Norbert; Beutel, Manfred E.; Zwerenz, Rudiger

2013-01-01

The objective of the study was to assess the impact of low-vision aids on quality of life. Interviews included a modified version of the National Eye Institute Visual Functioning Questionnaire (Modified German NEI VFQ-25), the Hospital Anxiety and Depression Scale, the Mini-Mental State Examination Blind, and Indicators of the Rehabilitation…

Proprioceptive deafferentation slows down the processing of visual hand feedback

DEFF Research Database (Denmark)

Balslev, Daniela; Miall, R Chris; Cole, Jonathan

2007-01-01

During visually guided movements both vision and proprioception inform the brain about the position of the hand, so interaction between these two modalities is presumed. Current theories suggest that this interaction occurs by sensory information from both sources being fused into a more reliable...... proprioception facilitates the processing of visual information during motor control. Subjects used a computer mouse to move a cursor to a screen target. In 28% of the trials, pseudorandomly, the cursor was rotated or the target jumped. Reaction time for the trajectory correction in response to this perturbation......, multimodal, percept of hand location. In the literature on perception, however, there is evidence that different sensory modalities interact in the allocation of attention, so that a stimulus in one modality facilitates the processing of a stimulus in a different modality. We investigated whether...

Identifying the computational requirements of an integrated top-down-bottom-up model for overt visual attention within an active vision system.

Directory of Open Access Journals (Sweden)

Sebastian McBride

Full Text Available Computational visual attention systems have been constructed in order for robots and other devices to detect and locate regions of interest in their visual world. Such systems often attempt to take account of what is known of the human visual system and employ concepts, such as 'active vision', to gain various perceived advantages. However, despite the potential for gaining insights from such experiments, the computational requirements for visual attention processing are often not clearly presented from a biological perspective. This was the primary objective of this study, attained through two specific phases of investigation: 1 conceptual modeling of a top-down-bottom-up framework through critical analysis of the psychophysical and neurophysiological literature, 2 implementation and validation of the model into robotic hardware (as a representative of an active vision system. Seven computational requirements were identified: 1 transformation of retinotopic to egocentric mappings, 2 spatial memory for the purposes of medium-term inhibition of return, 3 synchronization of 'where' and 'what' information from the two visual streams, 4 convergence of top-down and bottom-up information to a centralized point of information processing, 5 a threshold function to elicit saccade action, 6 a function to represent task relevance as a ratio of excitation and inhibition, and 7 derivation of excitation and inhibition values from object-associated feature classes. The model provides further insight into the nature of data representation and transfer between brain regions associated with the vertebrate 'active' visual attention system. In particular, the model lends strong support to the functional role of the lateral intraparietal region of the brain as a primary area of information consolidation that directs putative action through the use of a 'priority map'.

Cloud-based Networked Visual Servo Control

OpenAIRE

Wu, Haiyan; Lu, Lei; Chen, Chih-Chung; Hirche, Sandra; Kühnlenz, Kolja

2013-01-01

The performance of vision-based control systems, in particular of highly dynamic vision-based motion control systems, is often limited by the low sampling rate of the visual feedback caused by the long image processing time. In order to overcome this problem, the networked visual servo control, which integrates networked computational resources for cloud image processing, is considered in this article. The main contributions of this article are i) a real-time transport protocol for transmitti...

Near vision spectacle coverage and barriers to near vision ...

African Journals Online (AJOL)

easily help to address this visual disability.7 An average cost of near vision spectacle in Ghana is approximately. $ 5.8 Near-vision spectacle could be dispensed as single vision, bifocal or progressive eye glasses to meet near vi- sion needs.2. Recent evidence suggests that the ageing population in. Ghana is increasing ...

P1-7: Modern Display Technology in Vision Science: Assessment of OLED and LCD Monitors for Visual Experiments

Directory of Open Access Journals (Sweden)

Tobias Elze

2012-10-01

Full Text Available For many decades, cathode ray tube (CRT monitors have been the dominant display technology in vision science. However, in recent years, most manufacturers stopped their CRT production lines, which enforces the application of alternative display technology in the field of vision science. Here, we analyze liquid crystal displays (LCDs and organic light-emitting diode (OLED monitors for their applicability in vision science experiments. Based on extensive measurements of their photometric output, we compare these technologies and contrast them with classical CRT monitors. Vision scientists aim to accurately present both static and dynamic stimuli on their display devices. As for the presentation of static stimuli, we demonstrate an increased accuracy for LCD and OLED devices compared to CRT monitors, because the former exhibit a higher degree of independence of neighboring pixels. As for dynamic presentations, both CRTs and OLEDs outperform LCD devices in terms of accuracy, because dynamic presentations on LCDs require a reorientation of the liquid crystal molecules, so that successive frames in time depend on each other. Together with widely unknown and uncontrolled technical artifacts, these properties of LCDs may impair visual experiments that require high temporal precision. Therefore, OLED monitors are more suitable for vision science experiments with respect to both their static and their temporal characteristics. However, for certain applications in visual neuroscience, the low duty cycle of some OLED devices may introduce frequencies to the photometric output which fall within the window of visibility of neurons in the visual cortex and therefore interfere with single unit recordings.

Vision based systems for UAV applications

CERN Document Server

Kuś, Zygmunt

2013-01-01

This monograph is motivated by a significant number of vision based algorithms for Unmanned Aerial Vehicles (UAV) that were developed during research and development projects. Vision information is utilized in various applications like visual surveillance, aim systems, recognition systems, collision-avoidance systems and navigation. This book presents practical applications, examples and recent challenges in these mentioned application fields. The aim of the book is to create a valuable source of information for researchers and constructors of solutions utilizing vision from UAV. Scientists, researchers and graduate students involved in computer vision, image processing, data fusion, control algorithms, mechanics, data mining, navigation and IC can find many valuable, useful and practical suggestions and solutions. The latest challenges for vision based systems are also presented.

Uncertainty in visual processes predicts geometrical optical illusions.

Science.gov (United States)

Fermüller, Cornelia; Malm, Henrik

2004-03-01

It is proposed in this paper that many geometrical optical illusions, as well as illusory patterns due to motion signals in line drawings, are due to the statistics of visual computations. The interpretation of image patterns is preceded by a step where image features such as lines, intersections of lines, or local image movement must be derived. However, there are many sources of noise or uncertainty in the formation and processing of images, and they cause problems in the estimation of these features; in particular, they cause bias. As a result, the locations of features are perceived erroneously and the appearance of the patterns is altered. The bias occurs with any visual processing of line features; under average conditions it is not large enough to be noticeable, but illusory patterns are such that the bias is highly pronounced. Thus, the broader message of this paper is that there is a general uncertainty principle which governs the workings of vision systems, and optical illusions are an artifact of this principle.

Deep Neural Networks: A New Framework for Modeling Biological Vision and Brain Information Processing.

Science.gov (United States)

Kriegeskorte, Nikolaus

2015-11-24

Recent advances in neural network modeling have enabled major strides in computer vision and other artificial intelligence applications. Human-level visual recognition abilities are coming within reach of artificial systems. Artificial neural networks are inspired by the brain, and their computations could be implemented in biological neurons. Convolutional feedforward networks, which now dominate computer vision, take further inspiration from the architecture of the primate visual hierarchy. However, the current models are designed with engineering goals, not to model brain computations. Nevertheless, initial studies comparing internal representations between these models and primate brains find surprisingly similar representational spaces. With human-level performance no longer out of reach, we are entering an exciting new era, in which we will be able to build biologically faithful feedforward and recurrent computational models of how biological brains perform high-level feats of intelligence, including vision.

Estimates of Incidence and Prevalence of Visual Impairment, Low Vision, and Blindness in the United States.

Science.gov (United States)

Chan, Tiffany; Friedman, David S; Bradley, Chris; Massof, Robert

2018-01-01

Updated estimates of the prevalence and incidence rates of low vision and blindness are needed to inform policy makers and develop plans to meet the future demands for low vision rehabilitation services. To provide updated estimates of the incidence and prevalence of low vision and blindness in the United States. Visual acuity measurements as a function of age from the 2007-2008 National Health and Nutrition Examination Survey, with representation of racial and ethnic groups, were used to estimate the prevalence and incidence of visual impairments. Data from 6016 survey participants, ranging in age from younger than 18 years to older than 45 years, were obtained to estimate prevalence rates for different age groups. Incidence and prevalence rates of low vision (best-corrected visual acuity [BCVA] in the better-seeing eye of United States were estimated, using the 2010 US census data by age, from the rate models applied to the census projections for 2017, 2030, and 2050. Data were collected from November 1, 2007, to October 31, 2008. Data analysis took place from March 31, 2016, to March 19, 2017. Prevalence and incidence rates of low vision and blindness in the United States. Of the 6016 people in the study, 1714 (28.4%) were younger than 18 years of age, 2358 (39.1%) were 18 to 44 years of age, and 1944 (32.3%) were 45 years of age or older. There were 2888 male (48%) and 3128 female (52%) participants. The prevalence of low vision and blindness for older adults (≥45 years) in the United States in 2017 is estimated to be 3 894 406 persons (95% CI, 3 034 442-4 862 549 persons) with a BCVA less than 20/40, 1 483 703 persons (95% CI, 968 656-2 370 513 persons) with a BCVA less than 20/60, and 1 082 790 persons (95% CI, 637 771-1 741 864 persons) with a BCVA of 20/200 or less. The estimated 2017 annual incidence (projected from 2010 census data) of low vision and blindness among older adults (≥45 years) in the United States is 481�

Development and evaluation of vision rehabilitation devices.

Science.gov (United States)

Luo, Gang; Peli, Eli

2011-01-01

We have developed a range of vision rehabilitation devices and techniques for people with impaired vision due to either central vision loss or severely restricted peripheral visual field. We have conducted evaluation studies with patients to test the utilities of these techniques in an effort to document their advantages as well as their limitations. Here we describe our work on a visual field expander based on a head mounted display (HMD) for tunnel vision, a vision enhancement device for central vision loss, and a frequency domain JPEG/MPEG based image enhancement technique. All the evaluation studies included visual search paradigms that are suitable for conducting indoor controllable experiments.

Visions and visioning in foresight activities

DEFF Research Database (Denmark)

Jørgensen, Michael Søgaard; Grosu, Dan

2007-01-01

The paper discusses the roles of visioning processes and visions in foresight activities and in societal discourses and changes parallel to or following foresight activities. The overall topic can be characterised as the dynamics and mechanisms that make visions and visioning processes work...... or not work. The theoretical part of the paper presents an actor-network theory approach to the analyses of visions and visioning processes, where the shaping of the visions and the visioning and what has made them work or not work is analysed. The empirical part is based on analyses of the roles of visions...... and visioning processes in a number of foresight processes from different societal contexts. The analyses have been carried out as part of the work in the COST A22 network on foresight. A vision is here understood as a description of a desirable or preferable future, compared to a scenario which is understood...

Age-Related Psychophysical Changes and Low Vision

Science.gov (United States)

Dagnelie, Gislin

2013-01-01

When considering the burden of visual impairment on aging individuals and society at large, it is important to bear in mind that vision changes are a natural aspect of aging. In this article, we consider vision changes that are part of normal aging, the prevalence of abnormal vision changes caused by disorders of the visual system, and the anticipated incidence and impact of visual impairment as the US population ages. We then discuss the services available to reduce the impact of vision loss, and the extent to which those services can and should be improved, not only to be better prepared for the anticipated increase in low vision over the coming decades, but also to increase the awareness of interactions between visual impairment and comorbidities that are common among the elderly. Finally, we consider how to promote improved quality, availability, and acceptance of low vision care to lessen the impact of visual impairment on individuals, and its burden on society. PMID:24335074

Single-unit studies of visual motion processing in cat extrastriate areas

NARCIS (Netherlands)

Vajda, Ildiko

2003-01-01

Motion vision has high survival value and is a fundamental property of all visual systems. The old Greeks already studied motion vision, but the physiological basis of it first came under scrutiny in the late nineteenth century. Later, with the introduction of single-cell (single-unit)

Industrial image processing visual quality control in manufacturing

CERN Document Server

Demant, Christian; Garnica, Carsten

2013-01-01

This practical introduction focuses on how to build integrated solutions to industrial vision problems from individual algorithms. It gives a hands-on guide for setting up automated visual inspection systems using the NeuroCheck software package.

An FPGA Implementation of a Robot Control System with an Integrated 3D Vision System

Directory of Open Access Journals (Sweden)

Yi-Ting Chen

2015-05-01

Full Text Available Robot decision making and motion control are commonly based on visual information in various applications. Position-based visual servo is a technique for vision-based robot control, which operates in the 3D workspace, uses real-time image processing to perform tasks of feature extraction, and returns the pose of the object for positioning control. In order to handle the computational burden at the vision sensor feedback, we design a FPGA-based motion-vision integrated system that employs dedicated hardware circuits for processing vision processing and motion control functions. This research conducts a preliminary study to explore the integration of 3D vision and robot motion control system design based on a single field programmable gate array (FPGA chip. The implemented motion-vision embedded system performs the following functions: filtering, image statistics, binary morphology, binary object analysis, object 3D position calculation, robot inverse kinematics, velocity profile generation, feedback counting, and multiple-axes position feedback control.

A lightweight, inexpensive robotic system for insect vision.

Science.gov (United States)

Sabo, Chelsea; Chisholm, Robert; Petterson, Adam; Cope, Alex

2017-09-01

Designing hardware for miniaturized robotics which mimics the capabilities of flying insects is of interest, because they share similar constraints (i.e. small size, low weight, and low energy consumption). Research in this area aims to enable robots with similarly efficient flight and cognitive abilities. Visual processing is important to flying insects' impressive flight capabilities, but currently, embodiment of insect-like visual systems is limited by the hardware systems available. Suitable hardware is either prohibitively expensive, difficult to reproduce, cannot accurately simulate insect vision characteristics, and/or is too heavy for small robotic platforms. These limitations hamper the development of platforms for embodiment which in turn hampers the progress on understanding of how biological systems fundamentally work. To address this gap, this paper proposes an inexpensive, lightweight robotic system for modelling insect vision. The system is mounted and tested on a robotic platform for mobile applications, and then the camera and insect vision models are evaluated. We analyse the potential of the system for use in embodiment of higher-level visual processes (i.e. motion detection) and also for development of navigation based on vision for robotics in general. Optic flow from sample camera data is calculated and compared to a perfect, simulated bee world showing an excellent resemblance. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

An Overview of a UK Paediatric Visual Impaired Population and Low Vision Aid Provision

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Theodorou, Nana; Shipman, Tracey

2013-01-01

A retrospective study was carried out to evaluate the paediatric visual impaired population attending the Low Vision Clinic at Sheffield Teaching Hospitals NHS Foundation Trust, over a period of 14 years. Data were collected and analysed for children less than 17 years for prevalence, demographics, registration status, aetiologies, and types of…

Visual fields and eye morphology support color vision in a color-changing crab-spider.

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Insausti, Teresita C; Defrize, Jérémy; Lazzari, Claudio R; Casas, Jérôme

2012-03-01

Vision plays a major role in many spiders, being involved in prey hunting, orientation or substrate choice, among others. In Misumena vatia, which experiences morphological color changes, vision has been reported to be involved in substrate color matching. Electrophysiological evidence reveals that at least two types of photoreceptors are present in this species, but these data are not backed up by morphological evidence. This work analyzes the functional structure of the eyes of this spider and relates it to its color-changing abilities. A broad superposition of the visual field of the different eyes was observed, even between binocular regions of principal and secondary eyes. The frontal space is simultaneously analyzed by four eyes. This superposition supports the integration of the visual information provided by the different eye types. The mobile retina of the principal eyes of this spider is organized in three layers of three different types of rhabdoms. The third and deepest layer is composed by just one large rhabdom surrounded by dark screening pigments that limit the light entry. The three pairs of secondary eyes have all a single layer of rhabdoms. Our findings provide strong support for an involvement of the visual system in color matching in this spider. Copyright © 2011 Elsevier Ltd. All rights reserved.

Reward guides vision when it's your thing: trait reward-seeking in reward-mediated visual priming.

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Clayton Hickey

Full Text Available Reward-related mesolimbic dopamine is thought to play an important role in guiding animal behaviour, biasing approach towards potentially beneficial environmental stimuli and away from objects unlikely to garner positive outcome. This is considered to result in part from an impact on perceptual and attentional processes: dopamine initiates a series of cognitive events that result in the priming of reward-associated perceptual features. We have provided behavioural and electrophysiological evidence that this mechanism guides human vision in search, an effect we refer to as reward priming. We have also demonstrated that there is substantial individual variability in this effect. Here we show that behavioural differences in reward priming are predicted remarkably well by a personality index that captures the degree to which a person's behaviour is driven by reward outcome. Participants with reward-seeking personalities are found to be those who allocate visual resources to objects characterized by reward-associated visual features. These results add to a rapidly developing literature demonstrating the crucial role reward plays in attentional control. They additionally illustrate the striking impact personality traits can have on low-level cognitive processes like perception and selective attention.

Magnitude and Causes of Low Vision Disability (Moderate and Severe Visual Impairment) among Students of Al-Noor Institute for the Blind in Al-Hassa, Saudi Arabia: A case series.

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Al-Wadani, Fahad; Khandekar, Rajiv; Al-Hussain, Muneera A; Alkhawaja, Ahmed A; Khan, Mohammed Sarfaraz; Alsulaiman, Ramzy A

2012-02-01

This study aimed to estimate the magnitude and causes of low vision disability (severe visual impairment [SVI] and moderate visual impairment [MVI]) among students at Al-Noor Institute for the Blind (NIB) in Al-Hassa, Saudi Arabia in 2006. An optometrist conducted refraction of 122 eyes of the 61 students (27 boys and 34 girls) with MVI (vision visual acuity was ≥6/18 and in 28 (23%) eyes, it was visual impairment in 16 (13.1%) and 9 (7.4%) eyes. These students were prescribed optical and non-optical low vision aids. Retinal disease was the main cause of SVI and MVI in our series. Some students at Al-Noor Institute for the Blind have curable low vision conditions. Rehabilitation of low vision disability should be different from that offered to the absolutely blind.

Effect of rehabilitation worker input on visual function outcomes in individuals with low vision: study protocol for a randomised controlled trial.

Science.gov (United States)

Acton, Jennifer H; Molik, Bablin; Binns, Alison; Court, Helen; Margrain, Tom H

2016-02-24

Visual Rehabilitation Officers help people with a visual impairment maintain their independence. This intervention adopts a flexible, goal-centred approach, which may include training in mobility, use of optical and non-optical aids, and performance of activities of daily living. Although Visual Rehabilitation Officers are an integral part of the low vision service in the United Kingdom, evidence that they are effective is lacking. The purpose of this exploratory trial is to estimate the impact of a Visual Rehabilitation Officer on self-reported visual function, psychosocial and quality-of-life outcomes in individuals with low vision. In this exploratory, assessor-masked, parallel group, randomised controlled trial, participants will be allocated either to receive home visits from a Visual Rehabilitation Officer (n = 30) or to a waiting list control group (n = 30) in a 1:1 ratio. Adult volunteers with a visual impairment, who have been identified as needing rehabilitation officer input by a social worker, will take part. Those with an urgent need for a Visual Rehabilitation Officer or who have a cognitive impairment will be excluded. The primary outcome measure will be self-reported visual function (48-item Veterans Affairs Low Vision Visual Functioning Questionnaire). Secondary outcome measures will include psychological and quality-of-life metrics: the Patient Health Questionnaire (PHQ-9), the Warwick-Edinburgh Mental Well-being Scale (WEMWBS), the Adjustment to Age-related Visual Loss Scale (AVL-12), the Standardised Health-related Quality of Life Questionnaire (EQ-5D) and the UCLA Loneliness Scale. The interviewer collecting the outcomes will be masked to the group allocations. The analysis will be undertaken on a complete case and intention-to-treat basis. Analysis of covariance (ANCOVA) will be applied to follow-up questionnaire scores, with the baseline score as a covariate. This trial is expected to provide robust effect size estimates of the intervention

Vision holds a greater share in visuo-haptic object recognition than touch

DEFF Research Database (Denmark)

Kassuba, Tanja; Klinge, Corinna; Hölig, Cordula

2013-01-01

approach of multisensory integration would predict that haptics as the less efficient sense for object recognition gains more from integrating additional visual information than vice versa. To test for asymmetries between vision and touch in visuo-haptic interactions, we measured regional changes in brain...... processed the target object, being more pronounced for haptic than visual targets. This preferential response of visuo-haptic regions indicates a modality-specific asymmetry in crossmodal matching of visual and haptic object features, suggesting a functional primacy of vision over touch in visuo...

Estimation of metallurgical parameters of flotation process from froth visual features

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Mohammad Massinaei

2015-06-01

Full Text Available The estimation of metallurgical parameters of flotation process from froth visual features is the ultimate goal of a machine vision based control system. In this study, a batch flotation system was operated under different process conditions and metallurgical parameters and froth image data were determined simultaneously. Algorithms have been developed for measuring textural and physical froth features from the captured images. The correlation between the froth features and metallurgical parameters was successfully modeled, using artificial neural networks. It has been shown that the performance parameters of flotation process can be accurately estimated from the extracted image features, which is of great importance for developing automatic control systems.

Relating Standardized Visual Perception Measures to Simulator Visual System Performance

Science.gov (United States)

Kaiser, Mary K.; Sweet, Barbara T.

2013-01-01

Human vision is quantified through the use of standardized clinical vision measurements. These measurements typically include visual acuity (near and far), contrast sensitivity, color vision, stereopsis (a.k.a. stereo acuity), and visual field periphery. Simulator visual system performance is specified in terms such as brightness, contrast, color depth, color gamut, gamma, resolution, and field-of-view. How do these simulator performance characteristics relate to the perceptual experience of the pilot in the simulator? In this paper, visual acuity and contrast sensitivity will be related to simulator visual system resolution, contrast, and dynamic range; similarly, color vision will be related to color depth/color gamut. Finally, we will consider how some characteristics of human vision not typically included in current clinical assessments could be used to better inform simulator requirements (e.g., relating dynamic characteristics of human vision to update rate and other temporal display characteristics).

Vision in high-level football officials.

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Baptista, António Manuel Gonçalves; Serra, Pedro M; McAlinden, Colm; Barrett, Brendan T

2017-01-01

Officiating in football depends, at least to some extent, upon adequate visual function. However, there is no vision standard for football officiating and the nature of the relationship between officiating performance and level of vision is unknown. As a first step in characterising this relationship, we report on the clinically-measured vision and on the perceived level of vision in elite-level, Portuguese football officials. Seventy-one referees (R) and assistant referees (AR) participated in the study, representing 92% of the total population of elite level football officials in Portugal in the 2013/2014 season. Nine of the 22 Rs (40.9%) and ten of the 49 ARs (20.4%) were international-level. Information about visual history was also gathered. Perceived vision was assessed using the preference-values-assigned-to-global-visual-status (PVVS) and the Quality-of-Vision (QoV) questionnaire. Standard clinical vision measures (including visual acuity, contrast sensitivity and stereopsis) were gathered in a subset (n = 44, 62%) of the participants. Data were analysed according to the type (R/AR) and level (international/national) of official, and Bonferroni corrections were applied to reduce the risk of type I errors. Adopting criterion for statistical significance of pfootball officials were similar to published normative values for young, adult populations and similar between R and AR. Clinically-measured vision did not differ according to officiating level. Visual acuity measured with and without a pinhole disc indicated that around one quarter of participants may be capable of better vision when officiating, as evidenced by better acuity (≥1 line of letters) using the pinhole. Amongst the clinical visual tests we used, we did not find evidence for above-average performance in elite-level football officials. Although the impact of uncorrected mild to moderate refractive error upon officiating performance is unknown, with a greater uptake of eye examinations, visual

Vision-guided ocular growth in a mutant chicken model with diminished visual acuity.

Science.gov (United States)

Ritchey, Eric R; Zelinka, Christopher; Tang, Junhua; Liu, Jun; Code, Kimberly A; Petersen-Jones, Simon; Fischer, Andy J

2012-09-01

Visual experience is known to guide ocular growth. We tested the hypothesis that vision-guided ocular growth is disrupted in a model system with diminished visual acuity. We examine whether ocular elongation is influenced by form-deprivation (FD) and lens-imposed defocus in the Retinopathy, Globe Enlarged (RGE) chicken. Young RGE chicks have poor visual acuity, without significant retinal pathology, resulting from a mutation in guanine nucleotide-binding protein β3 (GNB3), also known as transducin β3 or Gβ3. The mutation in GNB3 destabilizes the protein and causes a loss of Gβ3 from photoreceptors and ON-bipolar cells (Ritchey et al., 2010). FD increased ocular elongation in RGE eyes in a manner similar to that seen in wild-type (WT) eyes. By comparison, the excessive ocular elongation that results from hyperopic defocus was increased, whereas myopic defocus failed to significantly decrease ocular elongation in RGE eyes. Brief daily periods of unrestricted vision interrupting FD prevented ocular elongation in RGE chicks in a manner similar to that seen in WT chicks. Glucagonergic amacrine cells differentially expressed the immediate early gene Egr1 in response to growth-guiding stimuli in RGE retinas, but the defocus-dependent up-regulation of Egr1 was lesser in RGE retinas compared to that of WT retinas. We conclude that high visual acuity, and the retinal signaling mediated by Gβ3, is not required for emmetropization and the excessive ocular elongation caused by FD and hyperopic defocus. However, the loss of acuity and Gβ3 from RGE retinas causes enhanced responses to hyperopic defocus and diminished responses to myopic defocus. Copyright © 2012 Elsevier Ltd. All rights reserved.

Acting without seeing: Eye movements reveal visual processing without awareness Miriam Spering & Marisa Carrasco

Science.gov (United States)

Spering, Miriam; Carrasco, Marisa

2015-01-01

Visual perception and eye movements are considered to be tightly linked. Diverse fields, ranging from developmental psychology to computer science, utilize eye tracking to measure visual perception. However, this prevailing view has been challenged by recent behavioral studies. We review converging evidence revealing dissociations between the contents of perceptual awareness and different types of eye movements. Such dissociations reveal situations in which eye movements are sensitive to particular visual features that fail to modulate perceptual reports. We also discuss neurophysiological, neuroimaging and clinical studies supporting the role of subcortical pathways for visual processing without awareness. Our review links awareness to perceptual-eye movement dissociations and furthers our understanding of the brain pathways underlying vision and movement with and without awareness. PMID:25765322

[Are Visual Field Defects Reversible? - Visual Rehabilitation with Brains].

Science.gov (United States)

Sabel, B A

2017-02-01

Visual field defects are considered irreversible because the retina and optic nerve do not regenerate. Nevertheless, there is some potential for recovery of the visual fields. This can be accomplished by the brain, which analyses and interprets visual information and is able to amplify residual signals through neuroplasticity. Neuroplasticity refers to the ability of the brain to change its own functional architecture by modulating synaptic efficacy. This is actually the neurobiological basis of normal learning. Plasticity is maintained throughout life and can be induced by repetitively stimulating (training) brain circuits. The question now arises as to how plasticity can be utilised to activate residual vision for the treatment of visual field loss. Just as in neurorehabilitation, visual field defects can be modulated by post-lesion plasticity to improve vision in glaucoma, diabetic retinopathy or optic neuropathy. Because almost all patients have some residual vision, the goal is to strengthen residual capacities by enhancing synaptic efficacy. New treatment paradigms have been tested in clinical studies, including vision restoration training and non-invasive alternating current stimulation. While vision training is a behavioural task to selectively stimulate "relative defects" with daily vision exercises for the duration of 6 months, treatment with alternating current stimulation (30 min. daily for 10 days) activates and synchronises the entire retina and brain. Though full restoration of vision is not possible, such treatments improve vision, both subjectively and objectively. This includes visual field enlargements, improved acuity and reaction time, improved orientation and vision related quality of life. About 70 % of the patients respond to the therapies and there are no serious adverse events. Physiological studies of the effect of alternating current stimulation using EEG and fMRI reveal massive local and global changes in the brain. These include

Low-level memory processes in vision.

Science.gov (United States)

Magnussen, S

2000-06-01

Psychophysical studies of the short-term memory for attributes or dimensions of the visual stimulus that are known to be important in early visual processing (spatial frequency, orientation, contrast, motion and color) identify a low-level perceptual memory mechanism. This proposed mechanism is located early in the visual processing stream, prior to the structural description system responsible for shape priming but beyond primary visual cortex (V1); it is composed of a series of parallel, special-purpose perceptual mechanisms with independent but limited processing resources. Each mechanism is devoted to the analysis of a single dimension and is coupled to a memory store.

Adjustable typography: an approach to enhancing low vision text accessibility.

Science.gov (United States)

Arditi, Aries

2004-04-15

Millions of people have low vision, a disability condition caused by uncorrectable or partially correctable disorders of the eye. The primary goal of low vision rehabilitation is increasing access to printed material. This paper describes how adjustable typography, a computer graphic approach to enhancing text accessibility, can play a role in this process, by allowing visually-impaired users to customize fonts to maximize legibility according to their own visual needs. Prototype software and initial testing of the concept is described. The results show that visually-impaired users tend to produce a variety of very distinct fonts, and that the adjustment process results in greatly enhanced legibility. But this initial testing has not yet demonstrated increases in legibility over and above the legibility of highly legible standard fonts such as Times New Roman.

Oregon State University Softball: Dynamic Visual Acuity Training for Improving Performance

OpenAIRE

Madsen, Bruce; Blair, Kyle

2017-01-01

Sports vision training involves eye focusing and movement workouts that center on the visual tracking of objects. The purpose of sports vision training is to improve performance in various sports by improving visual responses and processing, such as by lowering reaction times. In 2015, the Athletic Eye Institute started a sports vision-training program study with the Oregon State University Softball Team in the hopes of increasing the dynamic visual skills of their players. There were two aim...

Computer Vision Syndrome.

Science.gov (United States)

Randolph, Susan A

2017-07-01

With the increased use of electronic devices with visual displays, computer vision syndrome is becoming a major public health issue. Improving the visual status of workers using computers results in greater productivity in the workplace and improved visual comfort.

Experience-dependent plasticity from eye opening enables lasting, visual cortex-dependent enhancement of motion vision.

Science.gov (United States)

Prusky, Glen T; Silver, Byron D; Tschetter, Wayne W; Alam, Nazia M; Douglas, Robert M

2008-09-24

Developmentally regulated plasticity of vision has generally been associated with "sensitive" or "critical" periods in juvenile life, wherein visual deprivation leads to loss of visual function. Here we report an enabling form of visual plasticity that commences in infant rats from eye opening, in which daily threshold testing of optokinetic tracking, amid otherwise normal visual experience, stimulates enduring, visual cortex-dependent enhancement (>60%) of the spatial frequency threshold for tracking. The perceptual ability to use spatial frequency in discriminating between moving visual stimuli is also improved by the testing experience. The capacity for inducing enhancement is transitory and effectively limited to infancy; however, enhanced responses are not consolidated and maintained unless in-kind testing experience continues uninterrupted into juvenile life. The data show that selective visual experience from infancy can alone enable visual function. They also indicate that plasticity associated with visual deprivation may not be the only cause of developmental visual dysfunction, because we found that experientially inducing enhancement in late infancy, without subsequent reinforcement of the experience in early juvenile life, can lead to enduring loss of function.

Unveiling the mystery of visual information processing in human brain.

Science.gov (United States)

Diamant, Emanuel

2008-08-15

It is generally accepted that human vision is an extremely powerful information processing system that facilitates our interaction with the surrounding world. However, despite extended and extensive research efforts, which encompass many exploration fields, the underlying fundamentals and operational principles of visual information processing in human brain remain unknown. We still are unable to figure out where and how along the path from eyes to the cortex the sensory input perceived by the retina is converted into a meaningful object representation, which can be consciously manipulated by the brain. Studying the vast literature considering the various aspects of brain information processing, I was surprised to learn that the respected scholarly discussion is totally indifferent to the basic keynote question: "What is information?" in general or "What is visual information?" in particular. In the old days, it was assumed that any scientific research approach has first to define its basic departure points. Why was it overlooked in brain information processing research remains a conundrum. In this paper, I am trying to find a remedy for this bizarre situation. I propose an uncommon definition of "information", which can be derived from Kolmogorov's Complexity Theory and Chaitin's notion of Algorithmic Information. Embracing this new definition leads to an inevitable revision of traditional dogmas that shape the state of the art of brain information processing research. I hope this revision would better serve the challenging goal of human visual information processing modeling.

Trifocal intraocular lenses: a comparison of the visual performance and quality of vision provided by two different lens designs

Directory of Open Access Journals (Sweden)

Gundersen KG

2017-06-01

Full Text Available Kjell G Gundersen,1 Rick Potvin2 1IFocus Øyeklinikk AS, Haugesund, Norway; 2Science in Vision, Akron, NY, USA Purpose: To compare two different diffractive trifocal intraocular lens (IOL designs, evaluating longer-term refractive outcomes, visual acuity (VA at various distances, low contrast VA and quality of vision.Patients and methods: Patients with binocularly implanted trifocal IOLs of two different designs (FineVision [FV] and Panoptix [PX] were evaluated 6 months to 2 years after surgery. Best distance-corrected and uncorrected VA were tested at distance (4 m, intermediate (80 and 60 cm and near (40 cm. A binocular defocus curve was collected with the subject’s best distance correction in place. The preferred reading distance was determined along with the VA at that distance. Low contrast VA at distance was also measured. Quality of vision was measured with the National Eye Institute Visual Function Questionnaire near subset and the Quality of Vision questionnaire.Results: Thirty subjects in each group were successfully recruited. The binocular defocus curves differed only at vergences of −1.0 D (FV better, P=0.02, −1.5 and −2.00 D (PX better, P<0.01 for both. Best distance-corrected and uncorrected binocular vision were significantly better for the PX lens at 60 cm (P<0.01 with no significant differences at other distances. The preferred reading distance was between 42 and 43 cm for both lenses, with the VA at the preferred reading distance slightly better with the PX lens (P=0.04. There were no statistically significant differences by lens for low contrast VA (P=0.1 or for quality of vision measures (P>0.3.Conclusion: Both trifocal lenses provided excellent distance, intermediate and near vision, but several measures indicated that the PX lens provided better intermediate vision at 60 cm. This may be important to users of tablets and other handheld devices. Quality of vision appeared similar between the two lens designs

Computer vision camera with embedded FPGA processing

Science.gov (United States)

Lecerf, Antoine; Ouellet, Denis; Arias-Estrada, Miguel

2000-03-01

Traditional computer vision is based on a camera-computer system in which the image understanding algorithms are embedded in the computer. To circumvent the computational load of vision algorithms, low-level processing and imaging hardware can be integrated in a single compact module where a dedicated architecture is implemented. This paper presents a Computer Vision Camera based on an open architecture implemented in an FPGA. The system is targeted to real-time computer vision tasks where low level processing and feature extraction tasks can be implemented in the FPGA device. The camera integrates a CMOS image sensor, an FPGA device, two memory banks, and an embedded PC for communication and control tasks. The FPGA device is a medium size one equivalent to 25,000 logic gates. The device is connected to two high speed memory banks, an IS interface, and an imager interface. The camera can be accessed for architecture programming, data transfer, and control through an Ethernet link from a remote computer. A hardware architecture can be defined in a Hardware Description Language (like VHDL), simulated and synthesized into digital structures that can be programmed into the FPGA and tested on the camera. The architecture of a classical multi-scale edge detection algorithm based on a Laplacian of Gaussian convolution has been developed to show the capabilities of the system.

The effect of visual representation style in problem-solving: a perspective from cognitive processes.

Science.gov (United States)

Nyamsuren, Enkhbold; Taatgen, Niels A

2013-01-01

Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving.

The Effect of Visual Representation Style in Problem-Solving: A Perspective from Cognitive Processes

Science.gov (United States)

Nyamsuren, Enkhbold; Taatgen, Niels A.

2013-01-01

Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving. PMID:24260415

The effect of visual representation style in problem-solving: a perspective from cognitive processes.

Directory of Open Access Journals (Sweden)

Enkhbold Nyamsuren

Full Text Available Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving.

Low Vision Rehabilitation and Diabetic Retinopathy

International Nuclear Information System (INIS)

Khan, Sarfaraz A.

2007-01-01

Diabetic retinopathy is emerging as a major cause of blindness. Diabetic retinopathy calls for a multidisciplinary to the patients. Management of the patient requires a team work by the internist, diabetologist, dietician, ophthalmologist and low vision therapist. Diabetic retinopathy very often results in vision loss. It is important for ophthalmologist to recognize the importance of low vision rehabilitation in formulating appropriate treatment strategies. People with low vision loss due to diabetic retinopathy usually experience difficulty in daily life. Most people with diabetic retinopathy (who have remaining useful vision) can be helped with low vision devices. However, often one low vision device may not be suitable for all purposes. A comprehensive low vision evaluation is required to assess the person's current visual status, identify the goals and the visual needs, and then design an individualized vision rehabilitation program to meet these needs. (author)

Vision and vision-related outcome measures in multiple sclerosis

DEFF Research Database (Denmark)

Balcer, Laura J; Miller, David H; Reingold, Stephen C

2015-01-01

Visual impairment is a key manifestation of multiple sclerosis. Acute optic neuritis is a common, often presenting manifestation, but visual deficits and structural loss of retinal axonal and neuronal integrity can occur even without a history of optic neuritis. Interest in vision in multiple...... sclerosis is growing, partially in response to the development of sensitive visual function tests, structural markers such as optical coherence tomography and magnetic resonance imaging, and quality of life measures that give clinical meaning to the structure-function correlations that are unique...... of investigators involved in the development and study of visual outcomes in multiple sclerosis, which had, as its overriding goals, to review the state of the field and identify areas for future research. We review data and principles to help us understand the importance of vision as a model for outcomes...

Static and dynamic postural control in low-vision and normal-vision adults.

Science.gov (United States)

Tomomitsu, Mônica S V; Alonso, Angelica Castilho; Morimoto, Eurica; Bobbio, Tatiana G; Greve, Julia M D

2013-04-01

This study aimed to evaluate the influence of reduced visual information on postural control by comparing low-vision and normal-vision adults in static and dynamic conditions. Twenty-five low-vision subjects and twenty-five normal sighted adults were evaluated for static and dynamic balance using four protocols: 1) the Modified Clinical Test of Sensory Interaction on Balance on firm and foam surfaces with eyes opened and closed; 2) Unilateral Stance with eyes opened and closed; 3) Tandem Walk; and 4) Step Up/Over. The results showed that the low-vision group presented greater body sway compared with the normal vision during balance on a foam surface (p≤0.001), the Unilateral Stance test for both limbs (p≤0.001), and the Tandem Walk test. The low-vision group showed greater step width (p≤0.001) and slower gait speed (p≤0.004). In the Step Up/Over task, low-vision participants were more cautious in stepping up (right p≤0.005 and left p≤0.009) and in executing the movement (p≤0.001). These findings suggest that visual feedback is crucial for determining balance, especially for dynamic tasks and on foam surfaces. Low-vision individuals had worse postural stability than normal-vision adults in terms of dynamic tests and balance on foam surfaces.

Effects of rearranged vision on event-related lateralizations of the EEG during pointing.

Science.gov (United States)

Berndt, Isabelle; Franz, Volker H; Bülthoff, Heinrich H; Gotz, Karl G; Wascher, Edmund

2005-01-01

We used event-related lateralizations of the EEG (ERLs) and reversed vision to study visuomotor processing with conflicting proprioceptive and visual information during pointing. Reversed vision decreased arm-related lateralization, probably reflecting the simultaneous activity of left and right arm specific neurons: neurons in the hemisphere contralateral to the observed action were probably activated by visual feedback, neurons in the hemisphere contralateral to the response side by the somatomotor feedback. Lateralization related to the target in parietal cortex increased, indicating that visual to motor transformation in parietal cortex required additional time and resources with reversed vision. A short period of adaptation to an additional lateral displacement of the visual field increased arm-contralateral activity in parietal cortex during the movement. This is in agreement with the, which showed that adaptation to a lateral displacement of the visual field is reflected in increased parietal involvement during pointing.

Therapist-Assisted Rehabilitation of Visual Function and Hemianopia after Brain Injury: Intervention Study on the Effect of the Neuro Vision Technology Rehabilitation Program.

Science.gov (United States)

Rasmussen, Rune Skovgaard; Schaarup, Anne Marie Heltoft; Overgaard, Karsten

2018-02-27

Serious and often lasting vision impairments affect 30% to 35% of people following stroke. Vision may be considered the most important sense in humans, and even smaller permanent injuries can drastically reduce quality of life. Restoration of visual field impairments occur only to a small extent during the first month after brain damage, and therefore the time window for spontaneous improvements is limited. One month after brain injury causing visual impairment, patients usually will experience chronically impaired vision and the need for compensatory vision rehabilitation is substantial. The purpose of this study is to investigate whether rehabilitation with Neuro Vision Technology will result in a significant and lasting improvement in functional capacity in persons with chronic visual impairments after brain injury. Improving eyesight is expected to increase both physical and mental functioning, thus improving the quality of life. This is a prospective open label trial in which participants with chronic visual field impairments are examined before and after the intervention. Participants typically suffer from stroke or traumatic brain injury and will be recruited from hospitals and The Institute for the Blind and Partially Sighted. Treatment is based on Neuro Vision Technology, which is a supervised training course, where participants are trained in compensatory techniques using specially designed equipment. Through the Neuro Vision Technology procedure, the vision problems of each individual are carefully investigated, and personal data is used to organize individual training sessions. Cognitive face-to-face assessments and self-assessed questionnaires about both life and vision quality are also applied before and after the training. Funding was provided in June 2017. Results are expected to be available in 2020. Sample size is calculated to 23 participants. Due to age, difficulty in transport, and the time-consuming intervention, up to 25% dropouts are

Effect of absence of vision on posture

OpenAIRE

Alotaibi, Abdullah Z.; Alghadir, Ahmad; Iqbal, Zaheen A.; Anwer, Shahnawaz

2016-01-01

[Purpose] The visual system is one of the sensory systems that enables the body to assess and process information about the external environment. In the absence of vision, a blind person loses contact with the outside world and develops faulty motor patterns, which results in postural deficiencies. However, literature regarding the development of such deficiencies is limited. The aim of this study was to discuss the effect of absence of vision on posture, the possible biomechanics behind the ...

Book4All: A Tool to Make an e-Book More Accessible to Students with Vision/Visual-Impairments

Science.gov (United States)

Calabrò, Antonello; Contini, Elia; Leporini, Barbara

Empowering people who are blind or otherwise visually impaired includes ensuring that products and electronic materials incorporate a broad range of accessibility features and work well with screen readers and other assistive technology devices. This is particularly important for students with vision impairments. Unfortunately, authors and publishers often do not include specific criteria when preparing the contents. Consequently, e-books can be inadequate for blind and low vision users, especially for students. In this paper we describe a semi-automatic tool developed to support operators who adapt e-documents for visually impaired students. The proposed tool can be used to convert a PDF e-book into a more suitable accessible and usable format readable on desktop computer or on mobile devices.

The evolution of opsins and color vision: connecting genotype to a complex phenotype

Directory of Open Access Journals (Sweden)

Natasha I Bloch

2016-09-01

Full Text Available Dissecting the genetic basis of adaptive traits is key to our understanding of evolutionary processes. A major and essential step in the study of evolutionary genetics is drawing link between genotype and phenotype, which depends on the difficult process of defining the phenotype at different levels, from functional to organismal. Visual pigments are a key component of the visual system and their evolution could also provide important clues on the evolution of visual sensory system in response to sexual and natural selection. As a system in which genotype can be linked to phenotype, I will use visual pigments and color vision, particularly in birds, as a case of a complex phenotype. I aim to emphasize the difficulties in drawing the genotype-phenotype relationship for complex phenotypes and to highlight the challenges of doing so for color vision. The use of vision-based receiver models to quantify animal colors and patterns is increasingly important in many fields of evolutionary research, spanning studies of mate choice, predation, camouflage and sensory ecology. Given these models impact on evolution and ecology, it is important to provide other researchers with the opportunity to better understand animal vision and the corresponding advantages and limitations of these models.

Spatial vision in insects is facilitated by shaping the dynamics of visual input through behavioural action

Directory of Open Access Journals (Sweden)

Martin eEgelhaaf

2012-12-01

Full Text Available Insects such as flies or bees, with their miniature brains, are able to control highly aerobatic flight manoeuvres and to solve spatial vision tasks, such as avoiding collisions with obstacles, landing on objects or even localizing a previously learnt inconspicuous goal on the basis of environmental cues. With regard to solving such spatial tasks, these insects still outperform man-made autonomous flying systems. To accomplish their extraordinary performance, flies and bees have been shown by their characteristic behavioural actions to actively shape the dynamics of the image flow on their eyes (optic flow. The neural processing of information about the spatial layout of the environment is greatly facilitated by segregating the rotational from the translational optic flow component through a saccadic flight and gaze strategy. This active vision strategy thus enables the nervous system to solve apparently complex spatial vision tasks in a particularly efficient and parsimonious way. The key idea of this review is that biological agents, such as flies or bees, acquire at least part of their strength as autonomous systems through active interactions with their environment and not by simply processing passively gained information about the world. These agent-environment interactions lead to adaptive behaviour in surroundings of a wide range of complexity. Animals with even tiny brains, such as insects, are capable of performing extraordinarily well in their behavioural contexts by making optimal use of the closed action–perception loop. Model simulations and robotic implementations show that the smart biological mechanisms of motion computation and visually-guided flight control might be helpful to find technical solutions, for example, when designing micro air vehicles carrying a miniaturized, low-weight on-board processor.

Research on robot navigation vision sensor based on grating projection stereo vision

Science.gov (United States)

Zhang, Xiaoling; Luo, Yinsheng; Lin, Yuchi; Zhu, Lei

2016-10-01

A novel visual navigation method based on grating projection stereo vision for mobile robot in dark environment is proposed. This method is combining with grating projection profilometry of plane structured light and stereo vision technology. It can be employed to realize obstacle detection, SLAM (Simultaneous Localization and Mapping) and vision odometry for mobile robot navigation in dark environment without the image match in stereo vision technology and without phase unwrapping in the grating projection profilometry. First, we research the new vision sensor theoretical, and build geometric and mathematical model of the grating projection stereo vision system. Second, the computational method of 3D coordinates of space obstacle in the robot's visual field is studied, and then the obstacles in the field is located accurately. The result of simulation experiment and analysis shows that this research is useful to break the current autonomous navigation problem of mobile robot in dark environment, and to provide the theoretical basis and exploration direction for further study on navigation of space exploring robot in the dark and without GPS environment.

Low Vision Care: The Need to Maximise Visual Potential

Directory of Open Access Journals (Sweden)

Ramachandra Pararajasegaram

2004-01-01

Full Text Available People with low vision have residual vision with some light perception, but their vision loss does not lend itself to improvement by standard spectacles or medical or surgical treatment. Such persons have the potential for enhanced functional vision if they receive appropriate low vision care services.

Clinical observation of vitamin B12 eye drops for vision fatigue caused by visual display terminals

Directory of Open Access Journals (Sweden)

Qiang Guo

2016-07-01

Full Text Available AIM: To investigate the clinical effect of vitamin B12 eye drops for vision fatigue caused by visual display terminals(VDT. METHODS: Totally 50 patients(100 eyeswith vision fatigue caused by VDT were averagely divided into two groups. The control group were treated with normal saline,the treatment group were treated with vitamin B12 eye drops,3 times per day, one drop each time, continuous for 60d. Accommodative parameters and Schirmer Ⅰtest were measured and analyzed before and after treatment. RESULTS:After treatment, the results of Schirmer Ⅰtest, accommodative amplitude and accommodative facility of the treatment group were higher than those of the control group(all PPCONCLUSION: Vitamin B12 eye drops can lessen symptoms of dry eye, improve accommodative function and treat vision fatigue caused by VDT.

Bio-inspired vision

International Nuclear Information System (INIS)

Posch, C

2012-01-01

Nature still outperforms the most powerful computers in routine functions involving perception, sensing and actuation like vision, audition, and motion control, and is, most strikingly, orders of magnitude more energy-efficient than its artificial competitors. The reasons for the superior performance of biological systems are subject to diverse investigations, but it is clear that the form of hardware and the style of computation in nervous systems are fundamentally different from what is used in artificial synchronous information processing systems. Very generally speaking, biological neural systems rely on a large number of relatively simple, slow and unreliable processing elements and obtain performance and robustness from a massively parallel principle of operation and a high level of redundancy where the failure of single elements usually does not induce any observable system performance degradation. In the late 1980's, Carver Mead demonstrated that silicon VLSI technology can be employed in implementing ''neuromorphic'' circuits that mimic neural functions and fabricating building blocks that work like their biological role models. Neuromorphic systems, as the biological systems they model, are adaptive, fault-tolerant and scalable, and process information using energy-efficient, asynchronous, event-driven methods. In this paper, some basics of neuromorphic electronic engineering and its impact on recent developments in optical sensing and artificial vision are presented. It is demonstrated that bio-inspired vision systems have the potential to outperform conventional, frame-based vision acquisition and processing systems in many application fields and to establish new benchmarks in terms of redundancy suppression/data compression, dynamic range, temporal resolution and power efficiency to realize advanced functionality like 3D vision, object tracking, motor control, visual feedback loops, etc. in real-time. It is argued that future artificial vision systems

Vision Screening

Science.gov (United States)

... an efficient and cost-effective method to identify children with visual impairment or eye conditions that are likely to lead ... main goal of vision screening is to identify children who have or are at ... visual impairment unless treated in early childhood. Other problems that ...

Effects of Vision Restoration Training on Early Visual Cortex in Patients With Cerebral Blindness Investigated With Functional Magnetic Resonance Imaging

NARCIS (Netherlands)

Raemaekers, M.; Bergsma, D.P.; van Wezel, Richard Jack Anton; van der Wildt, G.J.; van den Berg, A.V.

Cerebral blindness is a loss of vision as a result of postchiasmatic damage to the visual pathways. Parts of the lost visual field can be restored through training. However, the neuronal mechanisms through which training effects occur are still unclear. We therefore assessed training-induced changes

Visual cognition influences early vision: the role of visual short-term memory in amodal completion.

Science.gov (United States)

Lee, Hyunkyu; Vecera, Shaun P

2005-10-01

A partly occluded visual object is perceptually filled in behind the occluding surface, a process known as amodal completion or visual interpolation. Previous research focused on the image-based properties that lead to amodal completion. In the present experiments, we examined the role of a higher-level visual process-visual short-term memory (VSTM)-in amodal completion. We measured the degree of amodal completion by asking participants to perform an object-based attention task on occluded objects while maintaining either zero or four items in visual working memory. When no items were stored in VSTM, participants completed the occluded objects; when four items were stored in VSTM, amodal completion was halted (Experiment 1). These results were not caused by the influence of VSTM on object-based attention per se (Experiment 2) or by the specific location of to-be-remembered items (Experiment 3). Items held in VSTM interfere with amodal completion, which suggests that amodal completion may not be an informationally encapsulated process, but rather can be affected by high-level visual processes.

Digital image processing and analysis human and computer vision applications with CVIPtools

CERN Document Server

Umbaugh, Scott E

2010-01-01

Section I Introduction to Digital Image Processing and AnalysisDigital Image Processing and AnalysisOverviewImage Analysis and Computer VisionImage Processing and Human VisionKey PointsExercisesReferencesFurther ReadingComputer Imaging SystemsImaging Systems OverviewImage Formation and SensingCVIPtools SoftwareImage RepresentationKey PointsExercisesSupplementary ExercisesReferencesFurther ReadingSection II Digital Image Analysis and Computer VisionIntroduction to Digital Image AnalysisIntroductionPreprocessingBinary Image AnalysisKey PointsExercisesSupplementary ExercisesReferencesFurther Read

Robot vision

International Nuclear Information System (INIS)

Hall, E.L.

1984-01-01

Almost all industrial robots use internal sensors such as shaft encoders which measure rotary position, or tachometers which measure velocity, to control their motions. Most controllers also provide interface capabilities so that signals from conveyors, machine tools, and the robot itself may be used to accomplish a task. However, advanced external sensors, such as visual sensors, can provide a much greater degree of adaptability for robot control as well as add automatic inspection capabilities to the industrial robot. Visual and other sensors are now being used in fundamental operations such as material processing with immediate inspection, material handling with adaption, arc welding, and complex assembly tasks. A new industry of robot vision has emerged. The application of these systems is an area of great potential

From humans to computers cognition through visual perception

CERN Document Server

Alexandrov, Viktor Vasilievitch

1991-01-01

This book considers computer vision to be an integral part of the artificial intelligence system. The core of the book is an analysis of possible approaches to the creation of artificial vision systems, which simulate human visual perception. Much attention is paid to the latest achievements in visual psychology and physiology, the description of the functional and structural organization of the human perception mechanism, the peculiarities of artistic perception and the expression of reality. Computer vision models based on these data are investigated. They include the processes of external d

Neuropharmacology of vision in goldfish: a review.

Science.gov (United States)

Mora-Ferrer, Carlos; Neumeyer, Christa

2009-05-01

The goldfish is one of the few animals exceptionally well analyzed in behavioral experiments and also in electrophysiological and neuroanatomical investigations of the retina. To get insight into the functional organization of the retina we studied color vision, motion detection and temporal resolution before and after intra-ocular injection of neuropharmaca with known effects on retinal neurons. Bicuculline, strychnine, curare, atropine, and dopamine D1- and D2-receptor antagonists were used. The results reviewed here indicate separate and parallel processing of L-cone contribution to different visual functions, and the influence of several neurotransmitters (dopamine, acetylcholine, glycine, and GABA) on motion vision, color vision, and temporal resolution.

Machine vision systems using machine learning for industrial product inspection

Science.gov (United States)

Lu, Yi; Chen, Tie Q.; Chen, Jie; Zhang, Jian; Tisler, Anthony

2002-02-01

Machine vision inspection requires efficient processing time and accurate results. In this paper, we present a machine vision inspection architecture, SMV (Smart Machine Vision). SMV decomposes a machine vision inspection problem into two stages, Learning Inspection Features (LIF), and On-Line Inspection (OLI). The LIF is designed to learn visual inspection features from design data and/or from inspection products. During the OLI stage, the inspection system uses the knowledge learnt by the LIF component to inspect the visual features of products. In this paper we will present two machine vision inspection systems developed under the SMV architecture for two different types of products, Printed Circuit Board (PCB) and Vacuum Florescent Displaying (VFD) boards. In the VFD board inspection system, the LIF component learns inspection features from a VFD board and its displaying patterns. In the PCB board inspection system, the LIF learns the inspection features from the CAD file of a PCB board. In both systems, the LIF component also incorporates interactive learning to make the inspection system more powerful and efficient. The VFD system has been deployed successfully in three different manufacturing companies and the PCB inspection system is the process of being deployed in a manufacturing plant.

Machine Vision Systems for Processing Hardwood Lumber and Logs

Science.gov (United States)

Philip A. Araman; Daniel L. Schmoldt; Tai-Hoon Cho; Dongping Zhu; Richard W. Conners; D. Earl Kline

1992-01-01

Machine vision and automated processing systems are under development at Virginia Tech University with support and cooperation from the USDA Forest Service. Our goals are to help U.S. hardwood producers automate, reduce costs, increase product volume and value recovery, and market higher value, more accurately graded and described products. Any vision system is...

Seeing via miniature eye movements: A dynamic hypothesis for vision

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Ehud eAhissar

2012-11-01

Full Text Available During natural viewing, the eyes are never still. Even during fixation, miniature movements of the eyes move the retinal image across tens of foveal photoreceptors. Most theories of vision implicitly assume that the visual system ignores these movements and somehow overcomes the resulting smearing. However, evidence has accumulated to indicate that fixational eye movements cannot be ignored by the visual system if fine spatial details are to be resolved. We argue that the only way the visual system can achieve its high resolution given its fixational movements is by seeing via these movements. Seeing via eye movements also eliminates the instability of the image, which would be induced by them otherwise. Here we present a hypothesis for vision, in which coarse details are spatially-encoded in gaze-related coordinates, and fine spatial details are temporally-encoded in relative retinal coordinates. The temporal encoding presented here achieves its highest resolution by encoding along the elongated axes of simple cell receptive fields and not across these axes as suggested by spatial models of vision. According to our hypothesis, fine details of shape are encoded by inter-receptor temporal phases, texture by instantaneous intra-burst rates of individual receptors, and motion by inter-burst temporal frequencies. We further describe the ability of the visual system to readout the encoded information and recode it internally. We show how reading out of retinal signals can be facilitated by neuronal phase-locked loops (NPLLs, which lock to the retinal jitter; this locking enables recoding of motion information and temporal framing of shape and texture processing. A possible implementation of this locking-and-recoding process by specific thalamocortical loops is suggested. Overall it is suggested that high-acuity vision is based primarily on temporal mechanisms of the sort presented here and low-acuity vision is based primarily on spatial mechanisms.

Understanding and preventing computer vision syndrome.

Science.gov (United States)

Loh, Ky; Redd, Sc

2008-01-01

The invention of computer and advancement in information technology has revolutionized and benefited the society but at the same time has caused symptoms related to its usage such as ocular sprain, irritation, redness, dryness, blurred vision and double vision. This cluster of symptoms is known as computer vision syndrome which is characterized by the visual symptoms which result from interaction with computer display or its environment. Three major mechanisms that lead to computer vision syndrome are extraocular mechanism, accommodative mechanism and ocular surface mechanism. The visual effects of the computer such as brightness, resolution, glare and quality all are known factors that contribute to computer vision syndrome. Prevention is the most important strategy in managing computer vision syndrome. Modification in the ergonomics of the working environment, patient education and proper eye care are crucial in managing computer vision syndrome.

UNDERSTANDING AND PREVENTING COMPUTER VISION SYNDROME

Directory of Open Access Journals (Sweden)

REDDY SC

2008-01-01

Full Text Available The invention of computer and advancement in information technology has revolutionized and benefited the society but at the same time has caused symptoms related to its usage such as ocular sprain, irritation, redness, dryness, blurred vision and double vision. This cluster of symptoms is known as computer vision syndrome which is characterized by the visual symptoms which result from interaction with computer display or its environment. Three major mechanisms that lead to computer vision syndrome are extraocular mechanism, accommodative mechanism and ocular surface mechanism. The visual effects of the computer such as brightness, resolution, glare and quality all are known factors that contribute to computer vision syndrome. Prevention is the most important strategy in managing computer vision syndrome. Modification in the ergonomics of the working environment, patient education and proper eye care are crucial in managing computer vision syndrome.

Psychophysical "blinding" methods reveal a functional hierarchy of unconscious visual processing.

Science.gov (United States)

Breitmeyer, Bruno G

2015-09-01

Numerous non-invasive experimental "blinding" methods exist for suppressing the phenomenal awareness of visual stimuli. Not all of these suppressive methods occur at, and thus index, the same level of unconscious visual processing. This suggests that a functional hierarchy of unconscious visual processing can in principle be established. The empirical results of extant studies that have used a number of different methods and additional reasonable theoretical considerations suggest the following tentative hierarchy. At the highest levels in this hierarchy is unconscious processing indexed by object-substitution masking. The functional levels indexed by crowding, the attentional blink (and other attentional blinding methods), backward pattern masking, metacontrast masking, continuous flash suppression, sandwich masking, and single-flash interocular suppression, fall at progressively lower levels, while unconscious processing at the lowest levels is indexed by eye-based binocular-rivalry suppression. Although unconscious processing levels indexed by additional blinding methods is yet to be determined, a tentative placement at lower levels in the hierarchy is also given for unconscious processing indexed by Troxler fading and adaptation-induced blindness, and at higher levels in the hierarchy indexed by attentional blinding effects in addition to the level indexed by the attentional blink. The full mapping of levels in the functional hierarchy onto cortical activation sites and levels is yet to be determined. The existence of such a hierarchy bears importantly on the search for, and the distinctions between, neural correlates of conscious and unconscious vision. Copyright © 2015 Elsevier Inc. All rights reserved.

Computer vision syndrome-A common cause of unexplained visual symptoms in the modern era.

Science.gov (United States)

Munshi, Sunil; Varghese, Ashley; Dhar-Munshi, Sushma

2017-07-01

The aim of this study was to assess the evidence and available literature on the clinical, pathogenetic, prognostic and therapeutic aspects of Computer vision syndrome. Information was collected from Medline, Embase & National Library of Medicine over the last 30 years up to March 2016. The bibliographies of relevant articles were searched for additional references. Patients with Computer vision syndrome present to a variety of different specialists, including General Practitioners, Neurologists, Stroke physicians and Ophthalmologists. While the condition is common, there is a poor awareness in the public and among health professionals. Recognising this condition in the clinic or in emergency situations like the TIA clinic is crucial. The implications are potentially huge in view of the extensive and widespread use of computers and visual display units. Greater public awareness of Computer vision syndrome and education of health professionals is vital. Preventive strategies should form part of work place ergonomics routinely. Prompt and correct recognition is important to allow management and avoid unnecessary treatments. © 2017 John Wiley & Sons Ltd.

New vision technology for multidimensional quality monitoring of continuous frying of meat

DEFF Research Database (Denmark)

Daugaard, Søren Blond; Adler-Nissen, Jens; Carstensen, Jens Michael

2010-01-01

. The vision technology can also detect even slight increases in the agglutination of the fried minced meat during the process. This agglutination is undesirable, but very difficult to measure on-line. The results indicate that multi-spectral vision technology may partially or totally Substitute visual......The potential of using multi-spectral vision technology for quality control in a continuous frying process was investigated. canonical discriminant analysis of the multi-spectral images of samples of fried minced meat and diced turkey Could clearly visualise the effect of different heat treatments...

A comparison of the sensitivity of EQ-5D, SF-6D and TTO utility values to changes in vision and perceived visual function in patients with primary open-angle glaucoma

Directory of Open Access Journals (Sweden)

Bozzani Fiammetta Maria

2012-08-01

Full Text Available Abstract Background Economic viability of treatments for primary open-angle glaucoma (POAG should be assessed objectively to prioritise health care interventions. This study aims to identify the methods for eliciting utility values (UVs most sensitive to differences in visual field and visual functioning in patients with POAG. As a secondary objective, the dimensions of generic health-related and vision-related quality of life most affected by progressive vision loss will be identified. Methods A total of 132 POAG patients were recruited. Three sets of utility values (EuroQoL EQ-5D, Short Form SF-6D, Time Trade Off and a measure of perceived visual functioning from the National Eye Institute Visual Function Questionnaire (VFQ-25 were elicited during face-to-face interviews. The sensitivity of UVs to differences in the binocular visual field, visual acuity and visual functioning measures was analysed using non-parametric statistical methods. Results Median utilities were similar across Integrated Visual Field score quartiles for EQ-5D (P = 0.08 whereas SF-6D and Time-Trade-Off UVs significantly decreased (p = 0.01 and p = 0.001, respectively. The VFQ-25 score varied across Integrated Visual Field and binocular visual acuity groups and was associated with all three UVs (P ≤ 0.001; most of its vision-specific sub-scales were associated with the vision markers. The most affected dimension was driving. A relationship with vision markers was found for the physical component of SF-36 and not for any dimension of EQ-5D. Conclusions The Time-Trade-Off was more sensitive than EQ-5D and SF-6D to changes in vision and visual functioning associated with glaucoma progression but could not measure quality of life changes in the mildest disease stages.

Implied motion language can influence visual spatial memory

NARCIS (Netherlands)

Vinson, David; Engelen, Jan; Zwaan, Rolf A; Matlock, Teenie; Dale, Rick

How do language and vision interact? Specifically, what impact can language have on visual processing, especially related to spatial memory? What are typically considered errors in visual processing, such as remembering the location of an object to be farther along its motion trajectory than it

Estimation of visual maps with a robot network equipped with vision sensors.

Science.gov (United States)

Gil, Arturo; Reinoso, Óscar; Ballesta, Mónica; Juliá, Miguel; Payá, Luis

2010-01-01

In this paper we present an approach to the Simultaneous Localization and Mapping (SLAM) problem using a team of autonomous vehicles equipped with vision sensors. The SLAM problem considers the case in which a mobile robot is equipped with a particular sensor, moves along the environment, obtains measurements with its sensors and uses them to construct a model of the space where it evolves. In this paper we focus on the case where several robots, each equipped with its own sensor, are distributed in a network and view the space from different vantage points. In particular, each robot is equipped with a stereo camera that allow the robots to extract visual landmarks and obtain relative measurements to them. We propose an algorithm that uses the measurements obtained by the robots to build a single accurate map of the environment. The map is represented by the three-dimensional position of the visual landmarks. In addition, we consider that each landmark is accompanied by a visual descriptor that encodes its visual appearance. The solution is based on a Rao-Blackwellized particle filter that estimates the paths of the robots and the position of the visual landmarks. The validity of our proposal is demonstrated by means of experiments with a team of real robots in a office-like indoor environment.

Estimation of Visual Maps with a Robot Network Equipped with Vision Sensors

Directory of Open Access Journals (Sweden)

Arturo Gil

2010-05-01

Full Text Available In this paper we present an approach to the Simultaneous Localization and Mapping (SLAM problem using a team of autonomous vehicles equipped with vision sensors. The SLAM problem considers the case in which a mobile robot is equipped with a particular sensor, moves along the environment, obtains measurements with its sensors and uses them to construct a model of the space where it evolves. In this paper we focus on the case where several robots, each equipped with its own sensor, are distributed in a network and view the space from different vantage points. In particular, each robot is equipped with a stereo camera that allow the robots to extract visual landmarks and obtain relative measurements to them. We propose an algorithm that uses the measurements obtained by the robots to build a single accurate map of the environment. The map is represented by the three-dimensional position of the visual landmarks. In addition, we consider that each landmark is accompanied by a visual descriptor that encodes its visual appearance. The solution is based on a Rao-Blackwellized particle filter that estimates the paths of the robots and the position of the visual landmarks. The validity of our proposal is demonstrated by means of experiments with a team of real robots in a office-like indoor environment.

Vision-based interaction

CERN Document Server

Turk, Matthew

2013-01-01

In its early years, the field of computer vision was largely motivated by researchers seeking computational models of biological vision and solutions to practical problems in manufacturing, defense, and medicine. For the past two decades or so, there has been an increasing interest in computer vision as an input modality in the context of human-computer interaction. Such vision-based interaction can endow interactive systems with visual capabilities similar to those important to human-human interaction, in order to perceive non-verbal cues and incorporate this information in applications such

Modeling foveal vision

NARCIS (Netherlands)

Florack, L.M.J.; Sgallari, F.; Murli, A.; Paragios, N.

2007-01-01

geometric model is proposed for an artificial foveal vision system, and its plausibility in the context of biological vision is explored. The model is based on an isotropic, scale invariant two-form that describes the spatial layout of receptive fields in the the visual sensorium (in the biological

A two-level real-time vision machine combining coarse and fine grained parallelism

DEFF Research Database (Denmark)

Jensen, Lars Baunegaard With; Kjær-Nielsen, Anders; Pauwels, Karl

2010-01-01

In this paper, we describe a real-time vision machine having a stereo camera as input generating visual information on two different levels of abstraction. The system provides visual low-level and mid-level information in terms of dense stereo and optical flow, egomotion, indicating areas...... a factor 90 and a reduction of latency of a factor 26 compared to processing on a single CPU--core. Since the vision machine provides generic visual information it can be used in many contexts. Currently it is used in a driver assistance context as well as in two robotic applications....

Adjustment to acquired vision loss in adults presenting for visual disability certification

Directory of Open Access Journals (Sweden)

Aditya Nakade

2017-01-01

Full Text Available Context: Rehabilitation of the visually disabled depends on how they adjust to loss; understanding contributing factors may help in effective rehabilitation. Aim: The aim of this study is to assess adjustment to acquired vision loss in adults. Settings and Design: This observational study, conducted in the Department of Ophthalmology at a tertiary-level teaching hospital, included thirty persons (25–65 years with <6/60 in the better eye, and vision loss since ≥6-months. Materials and Methods: Age, gender, rural/urban residence, education, current occupation, binocular distance vision, adjustment (Acceptance and Self-Worth Adjustment Scale, depression (Center for Epidemiologic Studies-Depression Scale, social support (Duke Social Support and Stress Scale, and personality (10-item Personality Inventory scale was recorded. Statistical Analysis: To determine their effect on adjustment, Student's t-test was used for categorical variables, Pearson's correlation for age, and Spearman's correlation for depression, personality trait and social support and stress. Results: Of 30 persons recruited, 24 were men (80%; 24 lived in urban areas (80%; 9 were employed (30%; and 14 (46.6% had studied < Class 3. Adjustment was low (range: 33%–60%; mean: 43.6 ± 5.73. Reported support was low (median: 27.2; interquartile range [IQR]: 18.1–36.3; reported stress was low (median: 0.09; IQR: 0–18.1. Predominant personality traits (max score 14 were “Agreeableness” (average 12.0 ± 1.68 and “Conscientiousness” (average 11.3 ± 2.12. Emotional stability (average 9.2 ± 2.53 was less prominent. Depression score ranged from 17 to 50 (average 31.6 ± 6.01. The factors studied did not influence adjustment. Conclusions: Although adjustment did not vary with factors studied, all patients were depressed. Since perceived support and emotional stability was low, attention could be directed to support networks. Training patients in handling emotions, and training

Stimulation of functional vision in children with perinatal brain damage.

Science.gov (United States)

Alimović, Sonja; Mejaski-Bosnjak, Vlatka

2011-01-01

Cerebral visual impairment (CVI) is one of the most common causes of bilateral visual loss, which frequently occurs due to perinatal brain injury. Vision in early life has great impact on acquisition of basic comprehensions which are fundamental for further development. Therefore, early detection of visual problems and early intervention is necessary. The aim of the present study is to determine specific visual functioning of children with perinatal brain damage and the influence of visual stimulation on development of functional vision at early age of life. We initially assessed 30 children with perinatal brain damage up to 3 years of age, who were reffered to our pediatric low vision cabinet in "Little house" from child neurologists, ophthalmologists Type and degree of visual impairment was determined according to functional vision assessment of each child. On the bases of those assessments different kind of visual stimulations were carried out with children who have been identified to have a certain visual impairment. Through visual stimulation program some of the children were stimulated with light stimulus, some with different materials under the ultraviolet (UV) light, and some with bright color and high contrast materials. Children were also involved in program of early stimulation of overall sensory motor development. Goals and methods of therapy were determined individually, based on observation of child's possibilities and need. After one year of program, reassessment was done. Results for visual functions and functional vision were compared to evaluate the improvement of the vision development. These results have shown that there was significant improvement in functional vision, especially in visual attention and visual communication.

Refractive errors, visual impairment, and the use of low-vision devices in albinism in Malawi.

Science.gov (United States)

Schulze Schwering, M; Kumar, N; Bohrmann, D; Msukwa, G; Kalua, K; Kayange, P; Spitzer, M S

2015-04-01

This study focuses on the refractive implications of albinism in Malawi, which is mostly associated with the burden of visual impairment. The main goal was to describe the refractive errors and to analyze whether patients with albinism in Malawi, Sub-Saharan Africa, benefit from refraction. Age, sex, refractive data, uncorrected and best-corrected visual acuity (UCVA, BCVA), colour vision, contrast sensitivity, and the prescription of sunglasses and low vision devices were collected for a group of 120 albino individuals with oculocutaneous albinism (OCA). Refractive errors were evaluated objectively and subjectively by retinoscopy, and followed by cycloplegic refraction to reconfirm the results. Best-corrected visual acuity (BCVA) was also assessed binocularly. One hundred and twenty albino subjects were examined, ranging in age from 4 to 25 years (median 12 years), 71 (59 %) boys and 49 (41 %) girls. All exhibited horizontal pendular nystagmus. Mean visual acuity improved from 0.98 (0.33) logMAR to 0.77 (0.15) logMAR after refraction (p < 0.001). The best improvement of VA was achieved in patients with mild to moderate myopia. Patients with albinism who were hyperopic more than +1.5 D hardly improved from refraction. With the rule (WTR) astigmatism was more present (37.5 %) than against the rule (ATR) astigmatism (3.8 %). Patients with astigmatism less than 1.5 D improved in 15/32 of cases (47 %) by 2 lines or more. Patients with astigmatism equal to or more than 1.5 D in any axis improved in 26/54 of cases (48 %) by 2 lines or more. Refraction improves visual acuity of children with oculocutaneous albinism in a Sub-Saharan African population in Malawi. The mean improvement was 2 logMAR units.

Temporal windows in visual processing: "prestimulus brain state" and "poststimulus phase reset" segregate visual transients on different temporal scales.

Science.gov (United States)

Wutz, Andreas; Weisz, Nathan; Braun, Christoph; Melcher, David

2014-01-22

Dynamic vision requires both stability of the current perceptual representation and sensitivity to the accumulation of sensory evidence over time. Here we study the electrophysiological signatures of this intricate balance between temporal segregation and integration in vision. Within a forward masking paradigm with short and long stimulus onset asynchronies (SOA), we manipulated the temporal overlap of the visual persistence of two successive transients. Human observers enumerated the items presented in the second target display as a measure of the informational capacity read-out from this partly temporally integrated visual percept. We observed higher β-power immediately before mask display onset in incorrect trials, in which enumeration failed due to stronger integration of mask and target visual information. This effect was timescale specific, distinguishing between segregation and integration of visual transients that were distant in time (long SOA). Conversely, for short SOA trials, mask onset evoked a stronger visual response when mask and targets were correctly segregated in time. Examination of the target-related response profile revealed the importance of an evoked α-phase reset for the segregation of those rapid visual transients. Investigating this precise mapping of the temporal relationships of visual signals onto electrophysiological responses highlights how the stream of visual information is carved up into discrete temporal windows that mediate between segregated and integrated percepts. Fragmenting the stream of visual information provides a means to stabilize perceptual events within one instant in time.

[The vision of welders in France].

Science.gov (United States)

Boissin, J P; Peyresblanques, J; Rollin, J P; Marini, F; Beaufils, D

2002-10-01

A study was conducted to measure the impact of welding on the vision of welders. This study was conducted in France by the occupational medicine staff of large companies on 1.131 people, namely 850 welders and 281 control subjects. This investigation included two examinations at the beginning and the end of a year. The investigative procedure examined the different welding processes, the percentage of working time spent on welding activity, the length of exposure in years, as well as the medical variables: the optical correction type and history of ocular traumatology. The Visiotest or the Ergovision were used for the visual examination, equipment in common use by occupational medicine departments. The welders were comparatively young (59.53% of them were less than 45 years old). Moreover, for 69.75% of the welders, more than 75% of their activity was devoted to welding. All currently used welding processes were represented, including the modern PLASMA-TIG welding process. No excessive blood alcohol levels were observed in all subjects, but welders did smoke slightly more than the control subjects (40% vs 33%). Self-medication was rather less frequent among the welders, except as regards the use of eye drops, where the proportions were clearly inverted. Optical correction for hyperopia was similar between the two groups; however, as regards myopia, the welders were corrected less often. Lastly, contact lens use was exceptional among the welders. Nearsightedness varied logically with age, but also, inexplicably, with the welding processes. Vision recovery time after exposure to glare was much longer among the welders, except for the PLASMA-TIG processes. No difference was observed in the other parameters of the study. No change in the visual functions studied was noted between the two examinations. The examination techniques used showed no impairment of the studied visual functions, probably because companies use protective and preventive eye care methods. Moreover

Aerial somersault performance under three visual conditions.

Science.gov (United States)

Hondzinski, J M; Darling, W G

2001-07-01

Experiments were designed to examine the visual contributions to performance of back aerial double somersaults by collegiate acrobats. Somersaults were performed on a trampoline under three visual conditions: (a) NORMAL acuity; (b) REDUCED acuity (subjects wore special contacts that blocked light reflected onto the central retina); and (c) NO VISION. Videotaped skill performances were rated by two NCAA judges and digitized for kinematic analyses. Subjects' performance scores were similar in NORMAL and REDUCED conditions and lowest in the NO VISION condition. Control of body movement, indicated by time-to-contact, was most variable in the NO VISION condition. Profiles of angular head and neck velocity revealed that when subjects could see, they slowed their heads prior to touchdown in time to process optical flow information and prepare for landing. There was not always enough time to process vision associated with object identification and prepare for touchdown. It was concluded that collegiate acrobats do not need to identify objects for their best back aerial double somersault performance.

A survey on vision-based human action recognition

NARCIS (Netherlands)

Poppe, Ronald Walter

Vision-based human action recognition is the process of labeling image sequences with action labels. Robust solutions to this problem have applications in domains such as visual surveillance, video retrieval and human–computer interaction. The task is challenging due to variations in motion

A Neuromorphic Approach for Tracking using Dynamic Neural Fields on a Programmable Vision-chip

OpenAIRE

Martel Julien N.P.; Sandamirskaya Yulia

2016-01-01

In artificial vision applications, such as tracking, a large amount of data captured by sensors is transferred to processors to extract information relevant for the task at hand. Smart vision sensors offer a means to reduce the computational burden of visual processing pipelines by placing more processing capabilities next to the sensor. In this work, we use a vision-chip in which a small processor with memory is located next to each photosensitive element. The architecture of this device is ...

Do school classrooms meet the visual requirements of children and recommended vision standards?

Directory of Open Access Journals (Sweden)

Kalpa Negiloni

Full Text Available Visual demands of school children tend to vary with diverse classroom environments. The study aimed to evaluate the distance and near Visual Acuity (VA demand in Indian school classrooms and their comparison with the recommended vision standards.The distance and near VA demands were assessed in 33 classrooms (grades 4 to 12 of eight schools. The VA threshold demand relied on the smallest size of distance and near visual task material and viewing distance. The logMAR equivalents of minimum VA demand at specific seating positions (desk and among different grades were evaluated. The near threshold was converted into actual near VA demand by including the acuity reserve. The existing dimensions of chalkboard and classroom, gross area in a classroom per student and class size in all the measured classrooms were compared to the government recommended standards.In 33 classrooms assessed (35±10 students per room, the average distance and near logMAR VA threshold demand was 0.31±0.17 and 0.44±0.14 respectively. The mean distance VA demand (minimum in front desk position was 0.56±0.18 logMAR. Increased distance threshold demand (logMAR range -0.06, 0.19 was noted in 7 classrooms (21%. The mean VA demand in grades 4 to 8 and grades 9 to 12 was 0.35±0.16 and 0.24±0.16 logMAR respectively and the difference was not statistically significant (p = 0.055. The distance from board to front desk was greater than the recommended standard of 2.2m in 27 classrooms (82%. The other measured parameters were noted to be different from the proposed standards in majority of the classrooms.The study suggests the inclusion of task demand assessment in school vision screening protocol to provide relevant guidance to school authorities. These findings can serve as evidence to accommodate children with mild to moderate visual impairment in the regular classrooms.

To Further the Near-Vision Visual Acuity Tests (3): For a Test Which Saves Time, Labor, and Expenses

OpenAIRE

高橋, ひとみ; 川端, 秀仁; 衞藤, 隆

2014-01-01

The Ministry of Education, Culture, Sports, Science and Technology of Japan has its advisory board to review the list of medical checkup for school children every ten years. In August 2013 the board found that there was a considerable number of school children who had poor near vision and thus learn in the class less efficiently. The board recommended that the Ministry consider whether to include a near-vision visual acuity test in a regular medical examination at school. It may not be known ...

Vision Related Quality of Life in Patients with Keratoconus

Directory of Open Access Journals (Sweden)

Sevda Aydin Kurna

2014-01-01

Full Text Available Purpose. The purpose of this study is to evaluate the vision related quality of life in patients with keratoconus by using the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25. Methods. Thirty patients presented with keratoconus (keratoconus group and 30 healthy patients (control group were included in this study. Twenty patients were using rigid gas permeable and 10 patients were not using contact lenses in keratoconus group. High and low contrast visual acuity and mean K values of the patients were recorded. Each subject completed the 25-item NEI-VFQ-25. Results. All subscales of NEI-VFQ-25 were lower in the keratoconus patients. The difference was more evident in the subscales of general vision, ocular pain, near vision, vision-specific mental health, vision-specific role difficulties, and peripheral vision P 0.4 in the better eye had lower distance vision, social functioning, mental health, and role difficulties. Meanwhile, patients with low visual acuity (logMAR > 0.4 in the worse eye had lower general health scores P<0.05. Conclusions. Vision related quality of life was worse in keratoconus patients. Success in the contact lens usage and maintaining higher visual acuity may improve vision related quality of life.

Accuracy and Feasibility of an Android-Based Digital Assessment Tool for Post Stroke Visual Disorders-The StrokeVision App.

Science.gov (United States)

Quinn, Terence J; Livingstone, Iain; Weir, Alexander; Shaw, Robert; Breckenridge, Andrew; McAlpine, Christine; Tarbert, Claire M

2018-01-01

Visual impairment affects up to 70% of stroke survivors. We designed an app (StrokeVision) to facilitate screening for common post stroke visual issues (acuity, visual fields, and visual inattention). We sought to describe the test time, feasibility, acceptability, and accuracy of our app-based digital visual assessments against (a) current methods used for bedside screening and (b) gold standard measures. Patients were prospectively recruited from acute stroke settings. Index tests were app-based assessments of fields and inattention performed by a trained researcher. We compared against usual clinical screening practice of visual fields to confrontation, including inattention assessment (simultaneous stimuli). We also compared app to gold standard assessments of formal kinetic perimetry (Goldman or Octopus Visual Field Assessment); and pencil and paper-based tests of inattention (Albert's, Star Cancelation, and Line Bisection). Results of inattention and field tests were adjudicated by a specialist Neuro-ophthalmologist. All assessors were masked to each other's results. Participants and assessors graded acceptability using a bespoke scale that ranged from 0 (completely unacceptable) to 10 (perfect acceptability). Of 48 stroke survivors recruited, the complete battery of index and reference tests for fields was successfully completed in 45. Similar acceptability scores were observed for app-based [assessor median score 10 (IQR: 9-10); patient 9 (IQR: 8-10)] and traditional bedside testing [assessor 10 (IQR: 9-10); patient 10 (IQR: 9-10)]. Median test time was longer for app-based testing [combined time to completion of all digital tests 420 s (IQR: 390-588)] when compared with conventional bedside testing [70 s, (IQR: 40-70)], but shorter than gold standard testing [1,260 s, (IQR: 1005-1,620)]. Compared with gold standard assessments, usual screening practice demonstrated 79% sensitivity and 82% specificity for detection of a stroke-related field defect

Color vision versus pattern visual evoked potentials in the assessment of subclinical optic pathway involvement in multiple sclerosis

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Fatih C Gundogan

2013-01-01

Full Text Available Background: Optic pathway involvement in multiple sclerosis is frequently the initial sign in the disease process. In most clinical applications, pattern visual evoked potential (PVEP is used in the assessment of optic pathway involvement. Objective: To question the value of PVEP against color vision assessment in the diagnosis of subclinical optic pathway involvement. Materials and Methods: This prospective, cross-sectional study included 20 multiple sclerosis patients without a history of optic neuritis, and 20 healthy control subjects. Farnsworth-Munsell (FM 100-Hue testing and PVEPs to 60-min arc and 15-min arc checks by using Roland-Consult RetiScan® system were performed. P 100 amplitude, P 100 latency in PVEP and total error scores (TES in FM 100-Hue test were assessed. Results: Expanded Disability Status Scale score and the time from diagnosis were 2.21 ± 2.53 (ranging from 0 to 7 and 4.1 ± 4.4 years. MS group showed significantly delayed P 100 latency for both checks (P 0.05 for all. 14 MS patients (70% had an increased TESs in FM-100 Hue, 11 (55% MS patients had delayed P 100 latency and 9 (45% had reduced P 100 amplitude. The areas under the ROC curves were 0.944 for FM-100 Hue test, 0.753 for P 100 latency, and 0.173 for P 100 amplitude. Conclusions: Color vision testing seems to be more sensitive than PVEP in detecting subclinical visual pathway involvement in MS.

Emotion improves and impairs early vision.

Science.gov (United States)

Bocanegra, Bruno R; Zeelenberg, René

2009-06-01

Recent studies indicate that emotion enhances early vision, but the generality of this finding remains unknown. Do the benefits of emotion extend to all basic aspects of vision, or are they limited in scope? Our results show that the brief presentation of a fearful face, compared with a neutral face, enhances sensitivity for the orientation of subsequently presented low-spatial-frequency stimuli, but diminishes orientation sensitivity for high-spatial-frequency stimuli. This is the first demonstration that emotion not only improves but also impairs low-level vision. The selective low-spatial-frequency benefits are consistent with the idea that emotion enhances magnocellular processing. Additionally, we suggest that the high-spatial-frequency deficits are due to inhibitory interactions between magnocellular and parvocellular pathways. Our results suggest an emotion-induced trade-off in visual processing, rather than a general improvement. This trade-off may benefit perceptual dimensions that are relevant for survival at the expense of those that are less relevant.

Vision-aided Monitoring and Control of Thermal Spray, Spray Forming, and Welding Processes

Science.gov (United States)

Agapakis, John E.; Bolstad, Jon

1993-01-01

Vision is one of the most powerful forms of non-contact sensing for monitoring and control of manufacturing processes. However, processes involving an arc plasma or flame such as welding or thermal spraying pose particularly challenging problems to conventional vision sensing and processing techniques. The arc or plasma is not typically limited to a single spectral region and thus cannot be easily filtered out optically. This paper presents an innovative vision sensing system that uses intense stroboscopic illumination to overpower the arc light and produce a video image that is free of arc light or glare and dedicated image processing and analysis schemes that can enhance the video images or extract features of interest and produce quantitative process measures which can be used for process monitoring and control. Results of two SBIR programs sponsored by NASA and DOE and focusing on the application of this innovative vision sensing and processing technology to thermal spraying and welding process monitoring and control are discussed.

Prism therapy and visual rehabilitation in homonymous visual field loss.

LENUS (Irish Health Repository)

O'Neill, Evelyn C

2012-02-01

PURPOSE: Homonymous visual field defects (HVFD) are common and frequently occur after cerebrovascular accidents. They significantly impair visual function and cause disability particularly with regard to visual exploration. The purpose of this study was to assess a novel interventional treatment of monocular prism therapy on visual functioning in patients with HVFD of varied etiology using vision targeted, health-related quality of life (QOL) questionnaires. Our secondary aim was to confirm monocular and binocular visual field expansion pre- and posttreatment. METHODS: Twelve patients with acquired, documented HVFD were eligible to be included. All patients underwent specific vision-targeted, health-related QOL questionnaire and monocular and binocular Goldmann perimetry before commencing prism therapy. Patients were fitted with monocular prisms on the side of the HVFD with the base-in the direction of the field defect creating a peripheral optical exotropia and field expansion. After the treatment period, QOL questionnaires and perimetry were repeated. RESULTS: Twelve patients were included in the treatment group, 10 of whom were included in data analysis. Overall, there was significant improvement within multiple vision-related, QOL functioning parameters, specifically within the domains of general health (p < 0.01), general vision (p < 0.05), distance vision (p < 0.01), peripheral vision (p < 0.05), role difficulties (p < 0.05), dependency (p < 0.05), and social functioning (p < 0.05). Visual field expansion was shown when measured monocularly and binocularly during the study period in comparison with pretreatment baselines. CONCLUSIONS: Patients with HVFD demonstrate decreased QOL. Monocular sector prisms can improve the QOL and expand the visual field in these patients.

Vision and vision-related outcome measures in multiple sclerosis

Science.gov (United States)

Balcer, Laura J.; Miller, David H.; Reingold, Stephen C.

2015-01-01

Visual impairment is a key manifestation of multiple sclerosis. Acute optic neuritis is a common, often presenting manifestation, but visual deficits and structural loss of retinal axonal and neuronal integrity can occur even without a history of optic neuritis. Interest in vision in multiple sclerosis is growing, partially in response to the development of sensitive visual function tests, structural markers such as optical coherence tomography and magnetic resonance imaging, and quality of life measures that give clinical meaning to the structure-function correlations that are unique to the afferent visual pathway. Abnormal eye movements also are common in multiple sclerosis, but quantitative assessment methods that can be applied in practice and clinical trials are not readily available. We summarize here a comprehensive literature search and the discussion at a recent international meeting of investigators involved in the development and study of visual outcomes in multiple sclerosis, which had, as its overriding goals, to review the state of the field and identify areas for future research. We review data and principles to help us understand the importance of vision as a model for outcomes assessment in clinical practice and therapeutic trials in multiple sclerosis. PMID:25433914

Investigating vision in schizophrenia through responses to humorous stimuli

Directory of Open Access Journals (Sweden)

Wolfgang Tschacher

2015-06-01

Full Text Available The visual environment of humans contains abundant ambiguity and fragmentary information. Therefore, an early step of vision must disambiguate the incessant stream of information. Humorous stimuli produce a situation that is strikingly analogous to this process: Funniness is associated with the incongruity contained in a joke, pun, or cartoon. Like in vision in general, appreciating a visual pun as funny necessitates disambiguation of incongruous information. Therefore, perceived funniness of visual puns was implemented to study visual perception in a sample of 36 schizophrenia patients and 56 healthy control participants. We found that both visual incongruity and Theory of Mind (ToM content of the puns were associated with increased experienced funniness. This was significantly less so in participants with schizophrenia, consistent with the gestalt hypothesis of schizophrenia, which would predict compromised perceptual organization in patients. The association of incongruity with funniness was not mediated by known predictors of humor appreciation, such as affective state, depression, or extraversion. Patients with higher excitement symptoms and, at a trend level, reduced cognitive symptoms, reported lower funniness experiences. An open question remained whether patients showed this deficiency of visual incongruity detection independent of their ToM deficiency. Humorous stimuli may be viewed as a convenient method to study perceptual processes, but also fundamental questions of higher-level cognition.

Vision in high-level football officials.

Directory of Open Access Journals (Sweden)

António Manuel Gonçalves Baptista

Full Text Available Officiating in football depends, at least to some extent, upon adequate visual function. However, there is no vision standard for football officiating and the nature of the relationship between officiating performance and level of vision is unknown. As a first step in characterising this relationship, we report on the clinically-measured vision and on the perceived level of vision in elite-level, Portuguese football officials. Seventy-one referees (R and assistant referees (AR participated in the study, representing 92% of the total population of elite level football officials in Portugal in the 2013/2014 season. Nine of the 22 Rs (40.9% and ten of the 49 ARs (20.4% were international-level. Information about visual history was also gathered. Perceived vision was assessed using the preference-values-assigned-to-global-visual-status (PVVS and the Quality-of-Vision (QoV questionnaire. Standard clinical vision measures (including visual acuity, contrast sensitivity and stereopsis were gathered in a subset (n = 44, 62% of the participants. Data were analysed according to the type (R/AR and level (international/national of official, and Bonferroni corrections were applied to reduce the risk of type I errors. Adopting criterion for statistical significance of p<0.01, PVVS scores did not differ between R and AR (p = 0.88, or between national- and international-level officials (p = 0.66. Similarly, QoV scores did not differ between R and AR in frequency (p = 0.50, severity (p = 0.71 or bothersomeness (p = 0.81 of symptoms, or between international-level vs national-level officials for frequency (p = 0.03 or bothersomeness (p = 0.07 of symptoms. However, international-level officials reported less severe symptoms than their national-level counterparts (p<0.01. Overall, 18.3% of officials had either never had an eye examination or if they had, it was more than 3 years previously. Regarding refractive correction, 4.2% had undergone refractive surgery and

The Hong Kong vision study: a pilot assessment of visual impairment in adults.

OpenAIRE

Van Newkirk, M R

1997-01-01

PURPOSE: The Hong Kong Adult Vision Pilot Study is a population based study of the distribution and determinants of eye disease in a random sample of the Chinese population age 40 and over. The present pilot study identifies the extent and causes of visual loss using methods developed in the United States and Australia. The pilot study uses the prevalence data to estimate the sample size necessary to predict the size of an effect a larger study may detect and the confidence with which that ef...

FLORA™: Phase I development of a functional vision assessment for prosthetic vision users.

Science.gov (United States)

Geruschat, Duane R; Flax, Marshall; Tanna, Nilima; Bianchi, Michelle; Fisher, Andy; Goldschmidt, Mira; Fisher, Lynne; Dagnelie, Gislin; Deremeik, Jim; Smith, Audrey; Anaflous, Fatima; Dorn, Jessy

2015-07-01

Research groups and funding agencies need a functional assessment suitable for an ultra-low vision population to evaluate the impact of new vision-restoration treatments. The purpose of this study was to develop a pilot assessment to capture the functional visual ability and well-being of subjects whose vision has been partially restored with the Argus II Retinal Prosthesis System. The Functional Low-Vision Observer Rated Assessment (FLORA) pilot assessment involved a self-report section, a list of functional visual tasks for observation of performance and a case narrative summary. Results were analysed to determine whether the interview questions and functional visual tasks were appropriate for this ultra-low vision population and whether the ratings suffered from floor or ceiling effects. Thirty subjects with severe to profound retinitis pigmentosa (bare light perception or worse in both eyes) were enrolled in a clinical trial and implanted with the Argus II System. From this population, 26 subjects were assessed with the FLORA. Seven different evaluators administered the assessment. All 14 interview questions were asked. All 35 tasks for functional vision were selected for evaluation at least once, with an average of 20 subjects being evaluated for each test item. All four rating options—impossible (33 per cent), difficult (23 per cent), moderate (24 per cent) and easy (19 per cent)—were used by the evaluators. Evaluators also judged the amount of vision they observed the subjects using to complete the various tasks, with 'vision only' occurring 75 per cent on average with the System ON, and 29 per cent with the System OFF. The first version of the FLORA was found to contain useful elements for evaluation and to avoid floor and ceiling effects. The next phase of development will be to refine the assessment and to establish reliability and validity to increase its value as an assessment tool for functional vision and well-being. © 2015 The Authors. Clinical

Causes of vision impairment and assessment of need for low vision services for students of blind schools in Nepal.

Science.gov (United States)

Kansakar, I; Thapa, H B; Salma, K C; Ganguly, S; Kandel, R P; Rajasekaran, S

The present study is first of its kind to evaluate causes of visual impairment of blind students in Nepal and assess their need for low vision rehabilitation services. To evaluate causes of vision impairment of students enrolled in blind schools in Nepal and assess the need for low vision rehabilitation services in these students. A survey was conducted in 12 blind schools in Nepal, which were registered with Nepal Association for Welfare of Blindness (NAWB).It was conducted by a team of an ophthalmologist and an optometrist, by using standard eye examination protocols of the World Health Organization Prevention of Blindness Program (WHO/PBL). Of the 345 students enrolled in 12 schools, 285 students were examined (response rate of 82.61%). The students were in the 5 - 29 years age group. Nearly three-fourth of the children had become blind within one year of age and 52.3% visually impaired at birth and 20.7% developed vision impairment within one year of age. After refraction, 26 students (9.12%) had mild visual impairment, 21 students (7.37%) had severe visual impairment and 238 students (83.51%) were blind. The main cause of vision impairment was found to be corneal 35.79% and retina diseases, mainly dystrophy, 20.35% followed by problems with the whole globe, lens and optic nerve, accounting for 13.33%, 12.63% and 12.98% respectively. The major etiological factors were those of childhood such as Vitamin A deficiency, measles and similar causes (42.11%) followed by hereditary causes (25.26%). Of the total students examined, 48.07% were visually impaired due to preventable causes and 16.14% treatable aggregating to 64.21% of avoidable blindness. Fifty seven (28.22%) students could read smaller than 2 M print size after low vision assessment for near and 33(15.78%) students benefited with telescopic trial for distance low vision. In Nepal, renewed focus on providing best possible quality of life for visually impaired children by proper low vision assessment and eye

Successful Outcomes from a Structured Curriculum Used in the Veterans Affairs Low Vision Intervention Trial

Science.gov (United States)

Stelmack, Joan A.; Rinne, Stephen; Mancil, Rickilyn M.; Dean, Deborah; Moran, D'Anna; Tang, X. Charlene; Cummings, Roger; Massof, Robert W.

2008-01-01

A low vision rehabilitation program with a structured curriculum was evaluated in a randomized controlled trial. The treatment group demonstrated large improvements in self-reported visual function (reading, mobility, visual information processing, visual motor skills, and overall). The team approach and the protocols of the treatment program are…

Patient-reported vision-related quality of life differences between superior and inferior hemifield visual field defects in primary open-angle glaucoma.

Science.gov (United States)

Cheng, Hui-Chen; Guo, Chao-Yu; Chen, Mei-Ju; Ko, Yu-Chieh; Huang, Nicole; Liu, Catherine Jui-ling

2015-03-01

Previous studies have found that glaucoma is associated with impaired patient-reported vision-related quality of life (pVRQOL) but few, to our knowledge, have assessed how the visual field (VF) defect location impacts the pVRQOL. To investigate the associations of VF defects in the superior vs inferior hemifields with pVRQOL outcomes in patients with primary open-angle glaucoma. Prospective cross-sectional study at a tertiary referral center from March 1, 2012, to January 1, 2013, including patients with primary open-angle glaucoma who had a best-corrected visual acuity in the better eye equal to or better than 20/60 and reliable VF tests. The pVRQOL was assessed by a validated Taiwanese version of the 25-item National Eye Institute Visual Function Questionnaire. Reliable VF tests obtained within 3 months of enrollment were transformed to binocular integrated VF (IVF). The IVF was further stratified by VF location (superior vs inferior hemifield). The association between each domain of the 25-item National Eye Institute Visual Function Questionnaire and superior or inferior hemifield IVF was determined using multivariable linear regression analysis. The analysis included 186 patients with primary open-angle glaucoma with a mean age of 59.1 years (range, 19-86 years) and IVF mean deviation (MD) of -4.84 dB (range, -27.56 to 2.17 dB). In the multivariable linear regression analysis, the MD of the full-field IVF showed positive associations with near activities (β = 0.05; R2 = 0.20; P < .001), vision-specific role difficulties (β = 0.04; R2 = 0.19; P = .01), vision-specific dependency (β = 0.04; R2 = 0.20; P < .001), driving (β = 0.05; R2 = 0.24; P < .001), peripheral vision (β = 0.03; R2 = 0.18; P = .02), and composite scores (β = 0.04; R2 = 0.27; P = .005). Subsequent analysis showed that the MD of the superior hemifield IVF was associated only with near activities (β = 0.04; R2�

75 FR 9480 - Qualification of Drivers; Exemption Applications; Vision

Science.gov (United States)

2010-03-02

... injury sustained as a child. The best corrected visual acuity in his right eye is light-perception only... medical opinion, Mr. Williford has sufficient visual acuity, color vision and peripheral vision to perform...

Setting visual pre-placement testing in a technology manufacturing environment.

Science.gov (United States)

Gowan, Nancy J

2014-01-01

Every day we use our eyes to perform activities of daily living and work. Aging changes as well as health conditions can impact an individual's visual function, making it more difficult to accurately perform work activities. Occupational therapists work closely with optometrists and employers to develop ways to accommodate for these changes so that the employee can continue to perform the work tasks. This manuscript outlines a case study of systematically developing visual demands analyses and pre-placement vision screening assessment protocols for individuals completing quality inspection positions. When the vision screening was completed, it was discovered that over 20% of the employees had visual deficits that were correctable. This screening process yielded improved quality results but also identification of previously undetected visual deficits. Further development of vision screening in the workplace is supported.

Algorithms for image processing and computer vision

CERN Document Server

Parker, J R

2010-01-01

A cookbook of algorithms for common image processing applications Thanks to advances in computer hardware and software, algorithms have been developed that support sophisticated image processing without requiring an extensive background in mathematics. This bestselling book has been fully updated with the newest of these, including 2D vision methods in content-based searches and the use of graphics cards as image processing computational aids. It's an ideal reference for software engineers and developers, advanced programmers, graphics programmers, scientists, and other specialists wh

Assessing Functional Vision Using Microcomputers.

Science.gov (United States)

Spencer, Simon; Ross, Malcolm

1989-01-01

The paper describes a software system which uses microcomputers to aid in the assessment of functional vision in visually impaired students. The software also aims to be visually stimulating and to develop hand-eye coordination, visual memory, and cognitive abilities. (DB)

VISUAL ABILITY IN AMBLYOPIC CHILDREN COMPARED TO CHILDREN WITH NORMAL VISUAL ACUITY

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Zorica Tončić

2016-03-01

Full Text Available Vision rehabilitation in adults with low vision, even in children, is achieved with special devices, called low vision aids, LVA. The aim of the study is to determine the degree of visual function in amblyopic children and daily activities that are best related to those of normally sighted peers with normal visual acuity. The subjects were divided into two groups, matched 1:1 by age and gender: the first group consisted of 19 amblyopic children, and the second one consisted of 19 children with normal visual acuity. The questionnaire used to assess visual ability was Cardiff Visual Ability Questionnaire for Children (CVAQC, a reliable instrument for measuring visual ability in children with low vision. The study was conducted in the only rehabilitation center for amblyopic children in this region, so this is also a pioneer study. The overall result of CVAQC in amblyopic children was 1.287 log vs.-2.956, representing statistically significantly poorer visual ability in comparison to peers without vision deficit (p˂0.005. Amblyopic children function best in entertainment activities, especially in listening music (-2.31 log; as for sport, these children report swimming to be their favourite activity (-0.99 log. In the field of education they show best results in language acquisition (-0.79 log and the worst in mathematics (3.13 log. The greatest problem is reading small print texts books (2.61 log. Low vision children have poorer result of visual function in comparison to their peers with normal visual acuity. A precise deficit assessment in the most important spheres of life can be determined by using the questionnaires, so the rehabilitation can be rightly chosen.

Magnitude and Causes of Low Vision Disability (Moderate and Severe Visual Impairment among Students of Al-Noor Institute for the Blind in Al-Hassa, Saudi Arabia; A case series

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Fahad Al-Wadani

2012-02-01

Full Text Available Objectives: This study aimed to estimate the magnitude and causes of low vision disability (severe visual impairment [SVI] and moderate visual impairment [MVI] among students at Al-Noor Institute for the Blind (NIB in Al-Hassa, Saudi Arabia in 2006. Methods: An optometrist conducted refraction of 122 eyes of the 61 students (27 boys and 34 girls with MVI (vision <6/18 to 6/60 and SVI (vision <6/60 to 3/60. Ophthalmologists examined the anterior and posterior segments, and analysed the outcomes of additional investigations to finalise the diagnosis. The results were categorised as ‘preventable’, ‘treatable’ and ‘not amenable to treatment’. The low vision care was also reviewed. Results: In 12 (9.8% eyes, visual acuity was ≥6/18 and in 28 (23% eyes, it was <3/60. MVI and SVI were found in 82 eyes (67.2%. Hereditary retinal disorders were found in 68 (55.7% eyes. Although refractive errors were found in 112 (91.8% eyes, isolated refractive error was found in only 9 students. Congenital glaucoma and cataract were responsible for visual impairment in 16 (13.1% and 9 (7.4% eyes. These students were prescribed optical and non-optical low vision aids. Conclusion: Retinal disease was the main cause of SVI and MVI in our series. Some students at Al-Noor Institute for the Blind have curable low vision conditions. Rehabilitation of low vision disability should be different from that offered to the absolutely blind.

Neural Mechanisms of Selective Visual Attention.

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Moore, Tirin; Zirnsak, Marc

2017-01-03

Selective visual attention describes the tendency of visual processing to be confined largely to stimuli that are relevant to behavior. It is among the most fundamental of cognitive functions, particularly in humans and other primates for whom vision is the dominant sense. We review recent progress in identifying the neural mechanisms of selective visual attention. We discuss evidence from studies of different varieties of selective attention and examine how these varieties alter the processing of stimuli by neurons within the visual system, current knowledge of their causal basis, and methods for assessing attentional dysfunctions. In addition, we identify some key questions that remain in identifying the neural mechanisms that give rise to the selective processing of visual information.

Will Brazilian Patented Naturoptic Method for Recovery of Healthy Vision be Helpful Linguistically?

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de Moraes, Ana Paula; Dos Santos Marques, Rosélia; Mc Leod, Roger David

2008-10-01

Naturoptics Inc. extends its patent(s) to further the teaching of vision-restoring process(es), foster cross-linguistic capabilities, and assist in the educational or financial opportunities of individuals and countries. Directors of Naturoptics Inc. hope to achieve this while testing David Matthew Mc Leod's observations that high visual acuity correlates with other mental and sensory processes. He and RDM often noticed that thought concepts (language percepts) are detectable even across species barriers, as when bears, moose, et c. made their intentions known to us in ways we were culturally willing to accept. This addresses aspects of language that seemed related to our understanding of human vision, and how it encodes cortically by spatial frequency content of a visual scene. Words representing the same meaning in two different languages will encode at precisely the same site in the visual cortex. Predictions: ``our memories,'' and cross-species, detection of certain thoughts, if equivalently ``seen'' as images, (spatial frequency content).

The prevalence and causes of decreased visual acuity – a study based on vision screening conducted at Enukweni and Mzuzu Foundation Primary Schools, Malawi

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Thom L

2016-12-01

Full Text Available Leaveson Thom,1 Sanchia Jogessar,1,2 Sara L McGowan,1 Fiona Lawless,1,2 1Department of Optometry, Mzuzu University, Mzuzu, Malawi; 2Brienholden Vision Institute, Durban, South Africa Aim: To determine the prevalence and causes of decreased visual acuity (VA among pupils recruited in two primary schools in Mzimba district, northern region of Malawi.Materials and methods: The study was based on the vision screening which was conducted by optometrists at Enukweni and Mzuzu Foundation Primary Schools. The measurements during the screening included unaided distance monocular VA by using Low Vision Resource Center and Snellen chart, pinhole VA on any subject with VA of less than 6/6, refraction, pupil evaluations, ocular movements, ocular health, and shadow test.Results: The prevalence of decreased VA was found to be low in school-going population (4%, n=594. Even though Enukweni Primary School had few participants than Mzuzu Foundation Primary School, it had high prevalence of decreased VA (5.8%, n=275 than Mzuzu Foundation Primary School (1.8%, n=319. The principal causes of decreased VA in this study were found to be amblyopia and uncorrected refractive errors, with myopia being the main cause than hyperopia.Conclusion: Based on the low prevalence of decreased VA due to myopia or hyperopia, it should not be concluded that refractive errors are an insignificant contributor to visual disability in Malawi. More vision screenings are required at a large scale on school-aged population to reflect the real situation on the ground. Cost-effective strategies are needed to address this easily treatable cause of vision impairment. Keywords: vision screening, refractive errors, visual acuity, Enukweni, Mzuzu foundation

Accuracy and Feasibility of an Android-Based Digital Assessment Tool for Post Stroke Visual Disorders—The StrokeVision App

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Terence J. Quinn

2018-03-01

Full Text Available BackgroundVisual impairment affects up to 70% of stroke survivors. We designed an app (StrokeVision to facilitate screening for common post stroke visual issues (acuity, visual fields, and visual inattention. We sought to describe the test time, feasibility, acceptability, and accuracy of our app-based digital visual assessments against (a current methods used for bedside screening and (b gold standard measures.MethodsPatients were prospectively recruited from acute stroke settings. Index tests were app-based assessments of fields and inattention performed by a trained researcher. We compared against usual clinical screening practice of visual fields to confrontation, including inattention assessment (simultaneous stimuli. We also compared app to gold standard assessments of formal kinetic perimetry (Goldman or Octopus Visual Field Assessment; and pencil and paper-based tests of inattention (Albert’s, Star Cancelation, and Line Bisection. Results of inattention and field tests were adjudicated by a specialist Neuro-ophthalmologist. All assessors were masked to each other’s results. Participants and assessors graded acceptability using a bespoke scale that ranged from 0 (completely unacceptable to 10 (perfect acceptability.ResultsOf 48 stroke survivors recruited, the complete battery of index and reference tests for fields was successfully completed in 45. Similar acceptability scores were observed for app-based [assessor median score 10 (IQR: 9–10; patient 9 (IQR: 8–10] and traditional bedside testing [assessor 10 (IQR: 9–10; patient 10 (IQR: 9–10]. Median test time was longer for app-based testing [combined time to completion of all digital tests 420 s (IQR: 390–588] when compared with conventional bedside testing [70 s, (IQR: 40–70], but shorter than gold standard testing [1,260 s, (IQR: 1005–1,620]. Compared with gold standard assessments, usual screening practice demonstrated 79% sensitivity and 82% specificity for

Telerehabilitation for people with low vision.

Science.gov (United States)

Bittner, Ava K; Wykstra, Stephanie L; Yoshinaga, Patrick D; Li, Tianjing

2015-08-31

Low vision affects over 300 million people worldwide and can compromise both activities of daily living and quality of life. Rehabilitative training and vision assistive equipment (VAE) may help, but some visually impaired people have limited resources to attend in-person visits at rehabilitation clinics. These people may be able to overcome barriers to care through remote, Internet-based consultation (i.e., telerehabilitation). To compare the effects of telerehabilitation with face-to-face (e.g., in-office or inpatient) vision rehabilitation services for improving vision-related quality of life and reading speed in people with visual function loss due to any ocular condition. Secondary objectives are to evaluate compliance with scheduled rehabilitation sessions, abandonment rates for visual assistive equipment devices, and patient satisfaction ratings. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015 Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1980 to June 2015), EMBASE (January 1980 to June 2015), PubMed (1980 to June 2015), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any language restriction or study design filter in the electronic searches; however, we restricted the searches from 1980 onwards because the Internet was not introduced to the public until 1982. We last searched the electronic databases on 15 June 2015. We planned to include randomized controlled trials (RCTs) or controlled clinical trials (CCTs) in which participants were diagnosed with low vision and were undergoing low vision rehabilitation using an Internet, web-based technology compared with an approach based on in-person consultations. Two authors independently screened titles and abstracts, and then full-text articles against

Vision after 53 years of blindness.

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Sikl, Radovan; Simecček, Michal; Porubanová-Norquist, Michaela; Bezdíček, Ondřej; Kremláček, Jan; Stodůlka, Pavel; Fine, Ione; Ostrovsky, Yuri

2013-01-01

Several studies have shown that visual recovery after blindness that occurs early in life is never complete. The current study investigated whether an extremely long period of blindness might also cause a permanent impairment of visual performance, even in a case of adult-onset blindness. We examined KP, a 71-year-old man who underwent a successful sight-restoring operation after 53 years of blindness. A set of psychophysical tests designed to assess KP's face perception, object recognition, and visual space perception abilities were conducted six months and eight months after the surgery. The results demonstrate that regardless of a lengthy period of normal vision and rich pre-accident perceptual experience, KP did not fully integrate this experience, and his visual performance remained greatly compromised. This was particularly evident when the tasks targeted finer levels of perceptual processing. In addition to the decreased robustness of his memory representations, which was hypothesized as the main factor determining visual impairment, other factors that may have affected KP's performance were considered, including compromised visual functions, problems with perceptual organization, deficits in the simultaneous processing of visual information, and reduced cognitive abilities.

Vision after 53 Years of Blindness

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Radovan Šikl

2013-12-01

Full Text Available Several studies have shown that visual recovery after blindness that occurs early in life is never complete. The current study investigated whether an extremely long period of blindness might also cause a permanent impairment of visual performance, even in a case of adult-onset blindness. We examined KP, a 71-year-old man who underwent a successful sight-restoring operation after 53 years of blindness. A set of psychophysical tests designed to assess KP's face perception, object recognition, and visual space perception abilities were conducted six months and eight months after the surgery. The results demonstrate that regardless of a lengthy period of normal vision and rich pre-accident perceptual experience, KP did not fully integrate this experience, and his visual performance remained greatly compromised. This was particularly evident when the tasks targeted finer levels of perceptual processing. In addition to the decreased robustness of his memory representations, which was hypothesized as the main factor determining visual impairment, other factors that may have affected KP's performance were considered, including compromised visual functions, problems with perceptual organization, deficits in the simultaneous processing of visual information, and reduced cognitive abilities.

Active vision and image/video understanding with decision structures based on the network-symbolic models

Science.gov (United States)

Kuvich, Gary

2003-08-01

Vision is a part of a larger information system that converts visual information into knowledge structures. These structures drive vision process, resolve ambiguity and uncertainty via feedback projections, and provide image understanding that is an interpretation of visual information in terms of such knowledge models. The ability of human brain to emulate knowledge structures in the form of networks-symbolic models is found. And that means an important shift of paradigm in our knowledge about brain from neural networks to "cortical software". Symbols, predicates and grammars naturally emerge in such active multilevel hierarchical networks, and logic is simply a way of restructuring such models. Brain analyzes an image as a graph-type decision structure created via multilevel hierarchical compression of visual information. Mid-level vision processes like clustering, perceptual grouping, separation of figure from ground, are special kinds of graph/network transformations. They convert low-level image structure into the set of more abstract ones, which represent objects and visual scene, making them easy for analysis by higher-level knowledge structures. Higher-level vision phenomena are results of such analysis. Composition of network-symbolic models works similar to frames and agents, combines learning, classification, analogy together with higher-level model-based reasoning into a single framework. Such models do not require supercomputers. Based on such principles, and using methods of Computational intelligence, an Image Understanding system can convert images into the network-symbolic knowledge models, and effectively resolve uncertainty and ambiguity, providing unifying representation for perception and cognition. That allows creating new intelligent computer vision systems for robotic and defense industries.

Sound improves diminished visual temporal sensitivity in schizophrenia

NARCIS (Netherlands)

de Boer-Schellekens, L.; Stekelenburg, J.J.; Maes, J.P.; van Gool, A.R.; Vroomen, J.

2014-01-01

Visual temporal processing and multisensory integration (MSI) of sound and vision were examined in individuals with schizophrenia using a visual temporal order judgment (TOJ) task. Compared to a non-psychiatric control group, persons with schizophrenia were less sensitive judging the temporal order

Vision Problems and Reduced Reading Outcomes in Queensland Schoolchildren.

Science.gov (United States)

Hopkins, Shelley; Sampson, Geoff P; Hendicott, Peter L; Wood, Joanne M

2017-03-01

To assess the relationship between vision and reading outcomes in Indigenous and non-Indigenous schoolchildren to determine whether vision problems are associated with lower reading outcomes in these populations. Vision testing and reading assessments were performed on 508 Indigenous and non-Indigenous schoolchildren in Queensland, Australia divided into two age groups: Grades 1 and 2 (6-7 years of age) and Grades 6 and 7 (12-13 years of age). Vision parameters measured included cycloplegic refraction, near point of convergence, heterophoria, fusional vergence range, rapid automatized naming, and visual motor integration. The following vision conditions were then classified based on the vision findings: uncorrected hyperopia, convergence insufficiency, reduced rapid automatized naming, and delayed visual motor integration. Reading accuracy and reading comprehension were measured with the Neale reading test. The effect of uncorrected hyperopia, convergence insufficiency, reduced rapid automatized naming, and delayed visual motor integration on reading accuracy and reading comprehension were investigated with ANCOVAs. The ANCOVAs explained a significant proportion of variance in both reading accuracy and reading comprehension scores in both age groups, with 40% of the variation in reading accuracy and 33% of the variation in reading comprehension explained in the younger age group, and 27% and 10% of the variation in reading accuracy and reading comprehension, respectively, in the older age group. The vision parameters of visual motor integration and rapid automatized naming were significant predictors in all ANCOVAs (P reading results were explained by reduced visual motor integration and rapid automatized naming results. Both reduced rapid automatized naming and visual motor integration were associated with poorer reading outcomes in Indigenous and non-Indigenous children. This is an important finding given the recent emphasis placed on Indigenous children

Quality of life in Nepalese patients with low vision and the impact of low vision services

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Rajendra Gyawali

2012-10-01

Conclusions: Low vision patients have poor quality of life as measured with the NEI VFQ-25. Low vision service is associated with improved visual function, better quality of life and high rate of patient satisfaction.

Valence, Not Utility, Underlies Reward-Driven Prioritization in Human Vision.

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Barbaro, Ludwig; Peelen, Marius V; Hickey, Clayton

2017-10-25

Objects associated with reward draw attention and evoke enhanced activity in visual cortex. What is the underlying mechanism? One possibility is that reward's impact on vision is mediated by unique circuitry that modulates sensory processing, selectively increasing the salience of reward-associated stimuli. Alternatively, effects of reward may be part of a more general mechanism that prioritizes the processing of any beneficial object, importantly including stimuli that are associated with the evasion of loss. Here, we test these competing hypotheses by having male and female humans detect naturalistic objects associated with monetary reward, the evasion of equivalent loss, or neither of these. If vision is economically normative, processing of objects associated with reward and evasion of loss should be prioritized relative to neutral stimuli. Results from fMRI and behavioral experiments show that this is not the case: whereas objects associated with reward were better detected and represented in ventral visual cortex, detection and representation of stimuli associated with the evasion of loss were degraded. Representations in parietal cortex reveal a notable exception to this pattern, showing enhanced encoding of both reward- and loss-associated stimuli. Experience-driven visual prioritization can thus be economically irrational, driven by valence rather than objective utility. SIGNIFICANCE STATEMENT Normative economic models propose that gain should have the same value as evasion of equivalent loss. Is human vision rational in this way? Objects associated with reward draw attention and are well represented in visual cortex. This is thought to have evolutionary origins, highlighting objects likely to provide benefit in the future. But benefit can be conferred not only through gain, but also through evasion of loss. Here we demonstrate that the visual system prioritizes real-world objects presented in images of natural scenes only when these objects have been

S4-3: Spatial Processing of Visual Motion

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Shin'ya Nishida

2012-10-01

Full Text Available Local motion signals are extracted in parallel by a bank of motion detectors, and their spatiotemporal interactions are processed in subsequent stages. In this talk, I will review our recent studies on spatial interactions in visual motion processing. First, we found two types of spatial pooling of local motion signals. Directionally ambiguous 1D local motion signals are pooled across orientation and space for solution of the aperture problem, while 2D local motion signals are pooled for estimation of global vector average (e.g., Amano et al., 2009 Journal of Vision 9(3:4 1–25. Second, when stimulus presentation is brief, coherent motion detection of dynamic random-dot kinematogram is not efficient. Nevertheless, it is significantly improved by transient and synchronous presentation of a stationary surround pattern. This suggests that centre-surround spatial interaction may help rapid perception of motion (Linares et al., submitted. Third, to know how the visual system encodes pairwise relationships between remote motion signals, we measured the temporal rate limit for perceiving the relationship of two motion directions presented at the same time at different spatial locations. Compared with similar tasks with luminance or orientation signals, motion comparison was more rapid and hence efficient. This high performance was affected little by inter-element separation even when it was increased up to 100 deg. These findings indicate the existence of specialized processes to encode long-range relationships between motion signals for quick appreciation of global dynamic scene structure (Maruya et al., in preparation.

Stereoscopic vision in the absence of the lateral occipital cortex.

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Jenny C A Read

2010-09-01

Full Text Available Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better than many control observers at using binocular disparity to judge whether an isolated object appears near or far, and to resolve ambiguous structure-from-motion. DF is, however, poor at using relative disparity between features at different locations across the visual field. This may stem from a difficulty in identifying the surface boundaries where relative disparity is available. We suggest that the ventral processing stream may play a critical role in enabling healthy observers to extract fine depth information from relative disparities within one surface or between surfaces located in different parts of the visual field.

Soft Computing Techniques in Vision Science

CERN Document Server

Yang, Yeon-Mo

2012-01-01

This Special Edited Volume is a unique approach towards Computational solution for the upcoming field of study called Vision Science. From a scientific firmament Optics, Ophthalmology, and Optical Science has surpassed an Odyssey of optimizing configurations of Optical systems, Surveillance Cameras and other Nano optical devices with the metaphor of Nano Science and Technology. Still these systems are falling short of its computational aspect to achieve the pinnacle of human vision system. In this edited volume much attention has been given to address the coupling issues Computational Science and Vision Studies.  It is a comprehensive collection of research works addressing various related areas of Vision Science like Visual Perception and Visual system, Cognitive Psychology, Neuroscience, Psychophysics and Ophthalmology, linguistic relativity, color vision etc. This issue carries some latest developments in the form of research articles and presentations. The volume is rich of contents with technical tools ...

Impact of low vision care on reading performance in children with multiple disabilities and visual impairment

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Krishna Kumar Ramani

2014-01-01

Full Text Available Background: Lack of evidence in literature to show low vision care enhances the reading performance in children with Multiple Disabilities and Visual Impairment (MDVI. Aim: To evaluate the effectiveness of Low Vision Care intervention on the reading performance of children with MDVI. Materials and Methods: Three subjects who were diagnosed to have cerebral palsy and visual impairment, studying in a special school were recruited for the study. All of them underwent detailed eye examination and low vision care evaluation at a tertiary eye care hospital. A single subject multiple baseline (study design was adopted and the study period was 16 weeks. The reading performance (reading speed, reading accuracy, reading fluency was evaluated during the baseline phase and the intervention phase. The median of all the reading parameters for each week was noted. The trend of the reading performance was graphically represented in both the phases. Results: Reading speed increased by 37 Word per minute, 37 Letters per minute and 5 letters per minute for the subject 1, 2 and 3 respectively after the intervention. Reading accuracy was 84%, 91% and 86.4% at the end of the baseline period and 98.7%, 98.4% and 99% at the end of 16 weeks for subject 1, 2 and 3 respectively. Average reading fluency score was 8.3, 7.1 and 5.5 in the baseline period and 10.2, 10.2 and 8.7 in the intervention period. Conclusion: This study shows evidence of noticeable improvement in reading performance of children with MDVI using a novel study design.

Visual Equivalence and Amodal Completion in Cuttlefish

OpenAIRE

Lin, I-Rong; Chiao, Chuan-Chin

2017-01-01

Modern cephalopods are notably the most intelligent invertebrates and this is accompanied by keen vision. Despite extensive studies investigating the visual systems of cephalopods, little is known about their visual perception and object recognition. In the present study, we investigated the visual processing of the cuttlefish Sepia pharaonis, including visual equivalence and amodal completion. Cuttlefish were trained to discriminate images of shrimp and fish using the operant conditioning pa...

Retinal image quality and visual stimuli processing by simulation of partial eye cataract

Science.gov (United States)

Ozolinsh, Maris; Danilenko, Olga; Zavjalova, Varvara

2016-10-01

Visual stimuli were demonstrated on a 4.3'' mobile phone screen inside a "Virtual Reality" adapter that allowed separation of the left and right eye visual fields. Contrast of the retina image thus can be controlled by the image on the phone screen and parallel to that at appropriate geometry by the AC voltage applied to scattering PDLC cell inside the adapter. Such optical pathway separation allows to demonstrate to both eyes spatially variant images, that after visual binocular fusion acquire their characteristic indications. As visual stimuli we used grey and different color (two opponent components to vision - red-green in L*a*b* color space) spatially periodical stimuli for left and right eyes; and with spatial content that by addition or subtraction resulted as clockwise or counter clockwise slanted Gabor gratings. We performed computer modeling with numerical addition or subtraction of signals similar to processing in brain via stimuli input decomposition in luminance and color opponency components. It revealed the dependence of the perception psychophysical equilibrium point between clockwise or counter clockwise perception of summation on one eye image contrast and color saturation, and on the strength of the retinal aftereffects. Existence of a psychophysical equilibrium point in perception of summation is only in the presence of a prior adaptation to a slanted periodical grating and at the appropriate slant orientation of adaptation grating and/or at appropriate spatial grating pattern phase according to grating nods. Actual observer perception experiments when one eye images were deteriorated by simulated cataract approved the shift of mentioned psychophysical equilibrium point on the degree of artificial cataract. We analyzed also the mobile devices stimuli emission spectra paying attention to areas sensitive to macula pigments absorption spectral maxima and blue areas where the intense irradiation can cause in abnormalities in periodic melatonin

What is stereoscopic vision good for?

Science.gov (United States)

Read, Jenny C. A.

2015-03-01

Stereo vision is a resource-intensive process. Nevertheless, it has evolved in many animals including mammals, birds, amphibians and insects. It must therefore convey significant fitness benefits. It is often assumed that the main benefit is improved accuracy of depth judgments, but camouflage breaking may be as important, particularly in predatory animals. In humans, for the last 150 years, stereo vision has been turned to a new use: helping us reproduce visual reality for artistic purposes. By recreating the different views of a scene seen by the two eyes, stereo achieves unprecedented levels of realism. However, it also has some unexpected effects on viewer experience. The disruption of established mechanisms for interpreting pictures may be one reason why some viewers find stereoscopic content disturbing. Stereo vision also has uses in ophthalmology. Clinical stereoacuity tests are used in the management of conditions such as strabismus and amblyopia as well as vision screening. Stereoacuity can reveal the effectiveness of therapy and even predict long-term outcomes post surgery. Yet current clinical stereo tests fall far short of the accuracy and precision achievable in the lab. At Newcastle University, we are exploiting the recent availability of autostereo 3D tablet computers to design a clinical stereotest app in the form of a game suitable for young children. Our goal is to enable quick, accurate and precise stereoacuity measures which will enable clinicians to obtain better outcomes for children with visual disorders.

Effect of NCAM on aged-related deterioration in vision.

Science.gov (United States)

Luke, Margaret Po-Shan; LeVatte, Terry L; O'Reilly, Amanda M; Smith, Benjamin J; Tremblay, François; Brown, Richard E; Clarke, David B

2016-05-01

The neural cell adhesion molecule (NCAM) is involved in developmental processes and age-associated cognitive decline; however, little is known concerning the effects of NCAM in the visual system during aging. Using anatomical, electrophysiological, and behavioral assays, we analyzed age-related changes in visual function of NCAM deficient (-/-) and wild-type mice. Anatomical analyses indicated that aging NCAM -/- mice had fewer retinal ganglion cells, thinner retinas, and fewer photoreceptor cell layers than age-matched controls. Electroretinogram testing of retinal function in young adult NCAM -/- mice showed a 2-fold increase in a- and b-wave amplitude compared with wild-type mice, but the retinal activity dropped dramatically to control levels when the animals reached 10 months. In behavioral tasks, NCAM -/- mice had no visual pattern discrimination ability and showed premature loss of vision as they aged. Together, these findings demonstrate that NCAM plays significant roles in the adult visual system in establishing normal retinal anatomy, physiology and function, and in maintaining vision during aging. Copyright © 2016 Elsevier Inc. All rights reserved.

Vision and the Nobel Prize.

Science.gov (United States)

Morais, Fábio Barreto

2018-04-01

The Nobel Prize is the world's foremost honor for scientific advances in medicine and other areas. Founded by Alfred Nobel, the prizes have been awarded annually since 1901. We reviewed the literature on persons who have won or competed for this prize in subjects related to vision and ophthalmology. The topics were divided into vision physiology, diagnostic and therapeutic methods, disease mechanism, and miscellaneous categories. Allvar Gullstrand is the only ophthalmologist to win a Nobel Prize; he is also the only one to receive it for work in ophthalmology. Other ophthalmologists that have been nominated were Hjalmar Schiötz (tonometer), Karl Koller (topical anesthesia), and Jules Gonin (retinal detachment). Other scientists have won the prize for eye-related research: Ragnar Granit, Haldan Hartline and George Wald (chemistry and physiology of vision), and David Hubel and Torsten Wiesel (processing in the visual system). Peter Medawar is the only person born in Brazil to have won the Nobel Prize.

Impact of visual impairment on vision-specific quality of life among older adults living in nursing home.

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Dev, Mahesh Kumar; Paudel, Nabin; Joshi, Niraj Dev; Shah, Dev Narayan; Subba, Shishir

2014-03-01

Visual impairment (VI) has a significant negative impact on quality of life (QoL) amongst older people living in nursing homes. The purpose of this study was to determine the prevalence of VI and blindness and to explore the association between severity of VI and vision-specific QoL among older people living in nursing homes of Kathmandu, Nepal. This cross-sectional study involved 158 residents aged 60 years or older residing in seven nursing homes of Kathmandu Valley, Nepal. Near acuity, presenting and the best corrected distance visual acuity (VA) were assessed in each eye and considered in the better eye after adequate refraction. A complete anterior and posterior segment examination was carried out. Face-to-face interviews were conducted using a 57-item Nursing Home Vision-Targeted Health-Related Quality of Life (NHVQoL) questionnaire. The mean age of residents was 75.60 ± 7.12 years and the majority were female (66.46%). The prevalence of VI and blindness was 45.57% and its leading cause was cataract, which was followed by age-related macular degeneration, corneal opacity, glaucoma and macular scar. The mean composite score of NHVQoL questionnaire was 52.22 ± 12.49. There was a consistent overall deterioration in the mean composite score as well as each subscale score of NHVQoL questionnaire with a worsening of VA. VI and blindness are highly prevalent among older people living in nursing homes. VI has a significant negative impact on vision-specific QoL. Vision-specific QoL is reduced, and the reduction in the QoL bears a positive association with severity of VI among older people living in nursing homes.

Quality of vision, patient satisfaction and long-term visual function after bilateral implantation of a low addition multifocal intraocular lens.

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Pedrotti, Emilio; Mastropasqua, Rodolfo; Bonetto, Jacopo; Demasi, Christian; Aiello, Francesco; Nucci, Carlo; Mariotti, Cesare; Marchini, Giorgio

2017-07-17

The aim of the current study was to compare the quality of vision, contrast sensitivity and patient satisfaction with a biaspheric, segmented, rotationally asymmetric IOL (Lentis Comfort LS-313 MF 15-Oculentis GmbH, Berlin, Germany) as opposed to those of a monofocal IOL. This prospective single-blind comparative study included two groups of patients affected by bilateral senile cataract who underwent lens extraction and IOL implantation. The first group received a bilateral implantation of a monofocal IOL, and the second group received a bilateral implantation of the Comfort IOL. Twelve months after surgery uncorrected and corrected visual acuity at different distances (30, 50, 70 cm and 4 m), defocus curve and contrast sensitivity were assessed. Patient's satisfaction and spectacle independence were evaluated by mean of the NEI RQL-42 questionnaire. No significant differences were found between the groups in terms of near vision. The group of patients implanted with a Comfort IOL obtained the best results at intermediate distances (50 and 70 cm P < .001). Both groups showed an excellent uncorrected distance visual acuity (4 m). No statistically significant differences were found in terms of corrected near, intermediate and distance visual acuity. Concerning contrast sensitivity, no statistically significant differences between the groups were observed at any cycles per degree. The NEI RQL-42 questionnaire showed statistically significant differences between the group for "near vision" (P = .015), "dependence on correction" (P = .048) and "suboptimal correction" (P < .001) subscales. Our findings indicated that the Comfort IOL +1.5 D provides a good intermediate spectacle independence together with a high quality of vision, with a low amount of subjective symptoms and a contrast sensitivity similar to those obtained with a monofocal IOL.

Beyond the Vestibulo-Ocular Reflex: Vestibular Input is Processed Centrally to Achieve Visual Stability

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Edwin S. Dalmaijer

2018-03-01

Full Text Available The current study presents a re-analysis of data from Zink et al. (1998, Electroencephalography and Clinical Neurophysiology, 107, who administered galvanic vestibular stimulation through unipolar direct current. They placed electrodes on each mastoid and applied either right or left anodal stimulation. Ocular torsion and visual tilt were measured under different stimulation intensities. New modelling introduced here demonstrates that directly proportional linear models fit reasonably well with the relationship between vestibular input and visual tilt, but not to that between vestibular input and ocular torsion. Instead, an exponential model characterised by a decreasing slope and an asymptote fitted best. These results demonstrate that in the results presented by Zink et al. (1998, ocular torsion could not completely account for visual tilt. This suggests that vestibular input is processed centrally to stabilise vision when ocular torsion is insufficient. Potential mechanisms and seemingly conflicting literature are discussed.

Vision screening in children: Is 7-9 years of age a threshold for visual impairment?

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Ertekin, Yusuf Haydar; Tekin, Murat; Uludag, Aysegul; Arikan, Sedat; Sahin, Erkan Melih

2016-01-01

The present study aimed to assess the prevalence of decreased visual acuity, strabismus, and spectacle wear in children aged 5 to 13 years. A cross-sectional study was performed in primary education schools. A total of 1938 participants, including 940 females (48.5%) and 998 males (51.5%) with a mean age 8.96 ± 2.31 (5-13 years old), were screened. The comparisons were performed with gender, age, and age groups. The children attended to vision screening were assigned to three age groups as 5-6 years, 7-9 years, and 10-13 years. The prevalence of the parameters was detected as decreased visual acuity 12.4%, strabismus 2.2%, and spectacle wear 6.9%. The prevalence of decreased visual acuity was significantly higher in girls and in children aged 7-9 years old (p = 0.013, p children aged 7-9 years old (p = 0.019, p visual acuity decrease in 33 of 106 (31.1%) children despite wearing own spectacle. There was no significant difference among three age groups for strabismus. Increased prevalence of decreased visual acuity, as well as the higher frequency of spectacle wear in children at ages of 7-9 years old may point out a threshold for visual impairment.

A telephone survey of low vision services in U.S. schools for the blind and visually impaired.

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Kran, Barry S; Wright, Darick W

2008-07-01

The scope of clinical low vision services and access to comprehensive eye care through U.S. schools for the blind and visually impaired is not well known. Advances in medicine and educational trends toward inclusion have resulted in higher numbers of visually impaired children with additional cognitive, motor, and developmental impairments enrolled in U.S. schools for the blind and visually impaired. The availability and frequency of eye care and vision education services for individuals with visual and multiple impairments at schools for the blind is explored in this report using data collected in a 24-item telephone survey from 35 of 42 identified U.S. schools for the blind. The results indicate that 54% of the contacted schools (19) offer clinical eye examinations. All of these schools provide eye care to the 6 to 21 age group, yet only 10 schools make this service available to children from birth to 3 years of age. In addition, two thirds of these schools discontinue eye care when the students graduate or transition to adult service agencies. The majority (94.7%) of eye care is provided by optometrists or a combination of optometry and ophthalmology, and 42.1% of these schools have an affiliation with an optometric institution. When there is a collaborative agreement, clinical services for students are available more frequently. The authors find that questions emerge regarding access to care, identification of appropriate models of care, and training of educational/medical/optometric personnel to meet the needs of a very complex patient population.

Visual search, visual streams, and visual architectures.

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Green, M

1991-10-01

Most psychological, physiological, and computational models of early vision suggest that retinal information is divided into a parallel set of feature modules. The dominant theories of visual search assume that these modules form a "blackboard" architecture: a set of independent representations that communicate only through a central processor. A review of research shows that blackboard-based theories, such as feature-integration theory, cannot easily explain the existing data. The experimental evidence is more consistent with a "network" architecture, which stresses that: (1) feature modules are directly connected to one another, (2) features and their locations are represented together, (3) feature detection and integration are not distinct processing stages, and (4) no executive control process, such as focal attention, is needed to integrate features. Attention is not a spotlight that synthesizes objects from raw features. Instead, it is better to conceptualize attention as an aperture which masks irrelevant visual information.

A new measure for the assessment of visual awareness in individuals with tunnel vision.

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AlSaqr, Ali M; Dickinson, Chris M

2017-01-01

Individuals with a restricted peripheral visual field or tunnel vision (TV) have problems moving about and avoiding obstacles. Some individuals adapt better than others and some use assistive optical aids, so measurement of the visual field is not sufficient to describe their performance. In the present study, we developed a new clinical test called the 'Assessment of Visual Awareness (AVA)', which can be used to measure detection of peripheral targets. The participants were 20 patients with TV due to retinitis pigmentosa (PTV) and 50 normally sighted participants with simulated tunnel vision (STV) using goggles. In the AVA test, detection times were measured, when subjects searched for 24 individually presented, one degree targets, randomly positioned in a 60 degrees noise background. Head and eye movements were allowed and the presentation time was unlimited. The test validity was investigated by correlating the detection times with the 'percentage of preferred walking speed' (PPWS) and the 'number of collisions' on an indoor mobility course. In PTV and STV, the detection times had significant negative correlation with the field of view. The detection times had significant positive relations with target location. In the STV, the detection time was significantly negatively correlated with the PPWS and significantly positively correlated with the collisions score on the indoor mobility course. In the PTV, the relationship was not statistically significant. No significant difference in performance of STV was found when repeating the test one to two weeks later. The proposed AVA test was sensitive to the field of view and target location. The test is unique in design, quick, simple to deliver and both repeatable and valid. It could be a valuable tool to test different rehabilitation strategies in patients with TV. © 2016 Optometry Australia.

Plaque Brachytherapy for Uveal Melanoma: A Vision Prognostication Model

International Nuclear Information System (INIS)

Khan, Niloufer; Khan, Mohammad K.; Bena, James; Macklis, Roger; Singh, Arun D.

2012-01-01

Purpose: To generate a vision prognostication model after plaque brachytherapy for uveal melanoma. Methods and Materials: All patients with primary single ciliary body or choroidal melanoma treated with iodine-125 or ruthenium-106 plaque brachytherapy between January 1, 2005, and June 30, 2010, were included. The primary endpoint was loss of visual acuity. Only patients with initial visual acuity better than or equal to 20/50 were used to evaluate visual acuity worse than 20/50 at the end of the study, and only patients with initial visual acuity better than or equal to 20/200 were used to evaluate visual acuity worse than 20/200 at the end of the study. Factors analyzed were sex, age, cataracts, diabetes, tumor size (basal dimension and apical height), tumor location, and radiation dose to the tumor apex, fovea, and optic disc. Univariate and multivariable Cox proportional hazards were used to determine the influence of baseline patient factors on vision loss. Kaplan-Meier curves (log rank analysis) were used to estimate freedom from vision loss. Results: Of 189 patients, 92% (174) were alive as of February 1, 2011. At presentation, visual acuity was better than or equal to 20/50 and better than or equal to 20/200 in 108 and 173 patients, respectively. Of these patients, 44.4% (48) had post-treatment visual acuity of worse than 20/50 and 25.4% (44) had post-treatment visual acuity worse than 20/200. By multivariable analysis, increased age (hazard ratio [HR] of 1.01 [1.00-1.03], P=.05), increase in tumor height (HR of 1.35 [1.22-1.48], P<.001), and a greater total dose to the fovea (HR of 1.01 [1.00-1.01], P<.001) were predictive of vision loss. This information was used to develop a nomogram predictive of vision loss. Conclusions: By providing a means to predict vision loss at 3 years after treatment, our vision prognostication model can be an important tool for patient selection and treatment counseling.

Plaque Brachytherapy for Uveal Melanoma: A Vision Prognostication Model

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Khan, Niloufer [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, Ohio (United States); Khan, Mohammad K. [Department of Radiation Oncology, Emory University School of Medicine, Atlanta, Georgia (United States); Bena, James [Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio (United States); Macklis, Roger [Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, Ohio (United States); Singh, Arun D., E-mail: singha@ccf.org [Department of Ophthalmic Oncology, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio (United States)

2012-11-01

Purpose: To generate a vision prognostication model after plaque brachytherapy for uveal melanoma. Methods and Materials: All patients with primary single ciliary body or choroidal melanoma treated with iodine-125 or ruthenium-106 plaque brachytherapy between January 1, 2005, and June 30, 2010, were included. The primary endpoint was loss of visual acuity. Only patients with initial visual acuity better than or equal to 20/50 were used to evaluate visual acuity worse than 20/50 at the end of the study, and only patients with initial visual acuity better than or equal to 20/200 were used to evaluate visual acuity worse than 20/200 at the end of the study. Factors analyzed were sex, age, cataracts, diabetes, tumor size (basal dimension and apical height), tumor location, and radiation dose to the tumor apex, fovea, and optic disc. Univariate and multivariable Cox proportional hazards were used to determine the influence of baseline patient factors on vision loss. Kaplan-Meier curves (log rank analysis) were used to estimate freedom from vision loss. Results: Of 189 patients, 92% (174) were alive as of February 1, 2011. At presentation, visual acuity was better than or equal to 20/50 and better than or equal to 20/200 in 108 and 173 patients, respectively. Of these patients, 44.4% (48) had post-treatment visual acuity of worse than 20/50 and 25.4% (44) had post-treatment visual acuity worse than 20/200. By multivariable analysis, increased age (hazard ratio [HR] of 1.01 [1.00-1.03], P=.05), increase in tumor height (HR of 1.35 [1.22-1.48], P<.001), and a greater total dose to the fovea (HR of 1.01 [1.00-1.01], P<.001) were predictive of vision loss. This information was used to develop a nomogram predictive of vision loss. Conclusions: By providing a means to predict vision loss at 3 years after treatment, our vision prognostication model can be an important tool for patient selection and treatment counseling.

Reconfigurable On-Board Vision Processing for Small Autonomous Vehicles

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James K. Archibald

2006-12-01

Full Text Available This paper addresses the challenge of supporting real-time vision processing on-board small autonomous vehicles. Local vision gives increased autonomous capability, but it requires substantial computing power that is difficult to provide given the severe constraints of small size and battery-powered operation. We describe a custom FPGA-based circuit board designed to support research in the development of algorithms for image-directed navigation and control. We show that the FPGA approach supports real-time vision algorithms by describing the implementation of an algorithm to construct a three-dimensional (3D map of the environment surrounding a small mobile robot. We show that FPGAs are well suited for systems that must be flexible and deliver high levels of performance, especially in embedded settings where space and power are significant concerns.

Reconfigurable On-Board Vision Processing for Small Autonomous Vehicles

Directory of Open Access Journals (Sweden)

Fife WadeS

2007-01-01

Full Text Available This paper addresses the challenge of supporting real-time vision processing on-board small autonomous vehicles. Local vision gives increased autonomous capability, but it requires substantial computing power that is difficult to provide given the severe constraints of small size and battery-powered operation. We describe a custom FPGA-based circuit board designed to support research in the development of algorithms for image-directed navigation and control. We show that the FPGA approach supports real-time vision algorithms by describing the implementation of an algorithm to construct a three-dimensional (3D map of the environment surrounding a small mobile robot. We show that FPGAs are well suited for systems that must be flexible and deliver high levels of performance, especially in embedded settings where space and power are significant concerns.

Why vision is not both hierarchical and feedforward

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Michael H Herzog

2014-10-01

Full Text Available In classical models of object recognition, first, basic features (e.g., edges and lines are analyzed by independent filters that mimic the receptive field profiles of V1 neurons. In a feedforward fashion, the outputs of these filters are fed to filters at the next processing stage, pooling information across several filters from the previous level, and so forth at subsequent processing stages. Low-level processing determines high-level processing. Information lost on lower stages is irretrievably lost. Models of this type have proven to be very successful in many fields of vision, but have failed to explain object recognition in general. Here, we present experiments that, first, show that, similar to demonstrations from the Gestaltists, figural aspects determine low-level processing (as much as the other way around. Second, performance on a single element depends on all the other elements in the visual scene. Small changes in the overall configuration can lead to large changes in performance. Third, grouping of elements is key. Only if we know how elements group across the entire visual field, we can determine performance on individual elements, i.e., challenging the classical stereotypical filtering approach, which is at the very heart of most vision models.

Ultraviolet vision in lacertid lizards: evidence from retinal structure, eye transmittance, SWS1 visual pigment genes and behaviour.

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Pérez i de Lanuza, Guillem; Font, Enrique

2014-08-15

Ultraviolet (UV) vision and UV colour patches have been reported in a wide range of taxa and are increasingly appreciated as an integral part of vertebrate visual perception and communication systems. Previous studies with Lacertidae, a lizard family with diverse and complex coloration, have revealed the existence of UV-reflecting patches that may function as social signals. However, confirmation of the signalling role of UV coloration requires demonstrating that the lizards are capable of vision in the UV waveband. Here we use a multidisciplinary approach to characterize the visual sensitivity of a diverse sample of lacertid species. Spectral transmission measurements of the ocular media show that wavelengths down to 300 nm are transmitted in all the species sampled. Four retinal oil droplet types can be identified in the lacertid retina. Two types are pigmented and two are colourless. Fluorescence microscopy reveals that a type of colourless droplet is UV-transmitting and may thus be associated with UV-sensitive cones. DNA sequencing shows that lacertids have a functional SWS1 opsin, very similar at 13 critical sites to that in the presumed ancestral vertebrate (which was UV sensitive) and other UV-sensitive lizards. Finally, males of Podarcis muralis are capable of discriminating between two views of the same stimulus that differ only in the presence/absence of UV radiance. Taken together, these results provide convergent evidence of UV vision in lacertids, very likely by means of an independent photopigment. Moreover, the presence of four oil droplet types suggests that lacertids have a four-cone colour vision system. © 2014. Published by The Company of Biologists Ltd.

Visual function and cognitive speed of processing mediate age-related decline in memory span and fluid intelligence.

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Clay, Olivio J; Edwards, Jerri D; Ross, Lesley A; Okonkwo, Ozioma; Wadley, Virginia G; Roth, David L; Ball, Karlene K

2009-06-01

To evaluate the relationship between sensory and cognitive decline, particularly with respect to speed of processing, memory span, and fluid intelligence. In addition, the common cause, sensory degradation and speed of processing hypotheses were compared. Structural equation modeling was used to investigate the complex relationships among age-related decrements in these areas. Cross-sectional data analyses included 842 older adult participants (M = 73 years). After accounting for age-related declines in vision and processing speed, the direct associations between age and memory span and between age and fluid intelligence were nonsignificant. Older age was associated with visual decline, which was associated with slower speed of processing, which in turn was associated with greater cognitive deficits. The findings support both the sensory degradation and speed of processing accounts of age-related, cognitive decline. Furthermore, the findings highlight positive aspects of normal cognitive aging in that older age may not be associated with a loss of fluid intelligence if visual sensory functioning and processing speed can be maintained.

First- and second-order contrast sensitivity functions reveal disrupted visual processing following mild traumatic brain injury.

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Spiegel, Daniel P; Reynaud, Alexandre; Ruiz, Tatiana; Laguë-Beauvais, Maude; Hess, Robert; Farivar, Reza

2016-05-01

Vision is disrupted by traumatic brain injury (TBI), with vision-related complaints being amongst the most common in this population. Based on the neural responses of early visual cortical areas, injury to the visual cortex would be predicted to affect both 1(st) order and 2(nd) order contrast sensitivity functions (CSFs)-the height and/or the cut-off of the CSF are expected to be affected by TBI. Previous studies have reported disruptions only in 2(nd) order contrast sensitivity, but using a narrow range of parameters and divergent methodologies-no study has characterized the effect of TBI on the full CSF for both 1(st) and 2(nd) order stimuli. Such information is needed to properly understand the effect of TBI on contrast perception, which underlies all visual processing. Using a unified framework based on the quick contrast sensitivity function, we measured full CSFs for static and dynamic 1(st) and 2(nd) order stimuli. Our results provide a unique dataset showing alterations in sensitivity for both 1(st) and 2(nd) order visual stimuli. In particular, we show that TBI patients have increased sensitivity for 1(st) order motion stimuli and decreased sensitivity to orientation-defined and contrast-defined 2(nd) order stimuli. In addition, our data suggest that TBI patients' sensitivity for both 1(st) order stimuli and 2(nd) order contrast-defined stimuli is shifted towards higher spatial frequencies. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The role of peripheral vision in saccade planning: learning from people with tunnel vision.

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Luo, Gang; Vargas-Martin, Fernando; Peli, Eli

2008-12-22

Both visually salient and top-down information are important in eye movement control, but their relative roles in the planning of daily saccades are unclear. We investigated the effect of peripheral vision loss on saccadic behaviors in patients with tunnel vision (visual field diameters 7 degrees-16 degrees) in visual search and real-world walking experiments. The patients made up to two saccades per second to their pre-saccadic blind areas, about half of which had no overlap between the post- and pre-saccadic views. In the visual search experiment, visual field size and the background (blank or picture) did not affect the saccade sizes and direction of patients (n = 9). In the walking experiment, the patients (n = 5) and normal controls (n = 3) had similar distributions of saccade sizes and directions. These findings might provide a clue about the large extent of the top-down mechanism influence on eye movement control.

[Quality of life in visual impaired children treated for Early Visual Stimulation].

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Messa, Alcione Aparecida; Nakanami, Célia Regina; Lopes, Marcia Caires Bestilleiro

2012-01-01

To evaluate the quality of life in visually impaired children followed in the Early Visual Stimulation Ambulatory of Unifesp in two moments, before and after rehabilitational intervention of multiprofessional team. A CVFQ quality of life questionnaire was used. This instrument has a version for less than three years old children and another one for children older than three years (three to seven years) divided in six subscales: General health, General vision health, Competence, Personality, Family impact and Treatment. The correlation between the subscales on two moments was significant. There was a statistically significant difference in general vision health (p=0,029) and other important differences obtained in general health, family impact and quality of life general score. The questionnaire showed to be effective in order to measure the quality of life related to vision on families followed on this ambulatory. The multidisciplinary interventions provided visual function and familiar quality of life improvement. The quality of life related to vision in children followed in Early Visual Stimulation Ambulatory of Unifesp showed a significant improvement on general vision health.

Surface Casting Defects Inspection Using Vision System and Neural Network Techniques

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Świłło S.J.

2013-12-01

Full Text Available The paper presents a vision based approach and neural network techniques in surface defects inspection and categorization. Depending on part design and processing techniques, castings may develop surface discontinuities such as cracks and pores that greatly influence the material’s properties Since the human visual inspection for the surface is slow and expensive, a computer vision system is an alternative solution for the online inspection. The authors present the developed vision system uses an advanced image processing algorithm based on modified Laplacian of Gaussian edge detection method and advanced lighting system. The defect inspection algorithm consists of several parameters that allow the user to specify the sensitivity level at which he can accept the defects in the casting. In addition to the developed image processing algorithm and vision system apparatus, an advanced learning process has been developed, based on neural network techniques. Finally, as an example three groups of defects were investigated demonstrates automatic selection and categorization of the measured defects, such as blowholes, shrinkage porosity and shrinkage cavity.

UNDERSTANDING AND PREVENTING COMPUTER VISION SYNDROME

OpenAIRE

REDDY SC; LOH KY

2008-01-01

The invention of computer and advancement in information technology has revolutionized and benefited the society but at the same time has caused symptoms related to its usage such as ocular sprain, irritation, redness, dryness, blurred vision and double vision. This cluster of symptoms is known as computer vision syndrome which is characterized by the visual symptoms which result from interaction with computer display or its environment. Three major mechanisms that lead to computer vision syn...

Impairing the useful field of view in natural scenes: Tunnel vision versus general interference.

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Ringer, Ryan V; Throneburg, Zachary; Johnson, Aaron P; Kramer, Arthur F; Loschky, Lester C

2016-01-01

A fundamental issue in visual attention is the relationship between the useful field of view (UFOV), the region of visual space where information is encoded within a single fixation, and eccentricity. A common assumption is that impairing attentional resources reduces the size of the UFOV (i.e., tunnel vision). However, most research has not accounted for eccentricity-dependent changes in spatial resolution, potentially conflating fixed visual properties with flexible changes in visual attention. Williams (1988, 1989) argued that foveal loads are necessary to reduce the size of the UFOV, producing tunnel vision. Without a foveal load, it is argued that the attentional decrement is constant across the visual field (i.e., general interference). However, other research asserts that auditory working memory (WM) loads produce tunnel vision. To date, foveal versus auditory WM loads have not been compared to determine if they differentially change the size of the UFOV. In two experiments, we tested the effects of a foveal (rotated L vs. T discrimination) task and an auditory WM (N-back) task on an extrafoveal (Gabor) discrimination task. Gabor patches were scaled for size and processing time to produce equal performance across the visual field under single-task conditions, thus removing the confound of eccentricity-dependent differences in visual sensitivity. The results showed that although both foveal and auditory loads reduced Gabor orientation sensitivity, only the foveal load interacted with retinal eccentricity to produce tunnel vision, clearly demonstrating task-specific changes to the form of the UFOV. This has theoretical implications for understanding the UFOV.

Quality of vision in refractive and cataract surgery, indirect measurers: review article.

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Parede, Taís Renata Ribeira; Torricelli, André Augusto Miranda; Mukai, Adriana; Vieira Netto, Marcelo; Bechara, Samir Jacob

2013-01-01

Visual acuity is the measurement of an individual's ability to recognize details of an object in a space. Visual function measurements in clinical ophthalmology are limited by factors such as maximum contrast and so it might not adequately reflect the real vision conditions at that moment as well as the subjective aspects of the world perception by the patient. The objective of a successful vision-restoring surgery lies not only in gaining visual acuity lines, but also in vision quality. Therefore, refractive and cataract surgeries have the responsibility of achieving quality results. It is difficult to define quality of vision by a single parameter, and the main functional-vision tests are: contrast sensitivity, disability glare, intraocular stray light and aberrometry. In the current review the different components of the visual function are explained and the several available methods to assess the vision quality are described.

Learning Building Layouts with Non-geometric Visual Information: The Effects of Visual Impairment and Age

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Kalia, Amy A.; Legge, Gordon E.; Giudice, Nicholas A.

2009-01-01

Previous studies suggest that humans rely on geometric visual information (hallway structure) rather than non-geometric visual information (e.g., doors, signs and lighting) for acquiring cognitive maps of novel indoor layouts. This study asked whether visual impairment and age affect reliance on non-geometric visual information for layout learning. We tested three groups of participants—younger (sighted, older (50–70 years) normally sighted, and low vision (people with heterogeneous forms of visual impairment ranging in age from 18–67). Participants learned target locations in building layouts using four presentation modes: a desktop virtual environment (VE) displaying only geometric cues (Sparse VE), a VE displaying both geometric and non-geometric cues (Photorealistic VE), a Map, and a Real building. Layout knowledge was assessed by map drawing and by asking participants to walk to specified targets in the real space. Results indicate that low-vision and older normally-sighted participants relied on additional non-geometric information to accurately learn layouts. In conclusion, visual impairment and age may result in reduced perceptual and/or memory processing that makes it difficult to learn layouts without non-geometric visual information. PMID:19189732

Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex

OpenAIRE

Scott, Gregory D.; Karns, Christina M.; Dow, Mark W.; Stevens, Courtney; Neville, Helen J.

2014-01-01

Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anatomical normalization across participants wer...

Visual processing speed in old age

DEFF Research Database (Denmark)

Habekost, Thomas; vogel, asmus; Rostrup, Egill

2013-01-01

of the speed of a particular psychological process that are not confounded by the speed of other processes. We used Bundesen's (1990) Theory of Visual Attention (TVA) to obtain specific estimates of processing speed in the visual system controlled for the influence of response latency and individual variations...... dramatic aging effects were found for the perception threshold and the visual apprehension span. In the visual domain, cognitive aging seems to be most clearly related to reductions in processing speed....

Mini-review: Far peripheral vision.

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Simpson, Michael J

2017-11-01

The region of far peripheral vision, beyond 60 degrees of visual angle, is important to the evaluation of peripheral dark shadows (negative dysphotopsia) seen by some intraocular lens (IOL) patients. Theoretical calculations show that the limited diameter of an IOL affects ray paths at large angles, leading to a dimming of the main image for small pupils, and to peripheral illumination by light bypassing the IOL for larger pupils. These effects are rarely bothersome, and cataract surgery is highly successful, but there is a need to improve the characterization of far peripheral vision, for both pseudophakic and phakic eyes. Perimetry is the main quantitative test, but the purpose is to evaluate pathologies rather than characterize vision (and object and image regions are no longer uniquely related in the pseudophakic eye). The maximum visual angle is approximately 105 0 , but there is limited information about variations with age, race, or refractive error (in case there is an unexpected link with the development of myopia), or about how clear cornea, iris location, and the limiting retina are related. Also, the detection of peripheral motion is widely recognized to be important, yet rarely evaluated. Overall, people rarely complain specifically about this visual region, but with "normal" vision including an IOL for >5% of people, and increasing interest in virtual reality and augmented reality, there are new reasons to characterize peripheral vision more completely. Copyright © 2017 Elsevier Ltd. All rights reserved.

A malaria diagnostic tool based on computer vision screening and visualization of Plasmodium falciparum candidate areas in digitized blood smears.

Directory of Open Access Journals (Sweden)

Nina Linder

Full Text Available INTRODUCTION: Microscopy is the gold standard for diagnosis of malaria, however, manual evaluation of blood films is highly dependent on skilled personnel in a time-consuming, error-prone and repetitive process. In this study we propose a method using computer vision detection and visualization of only the diagnostically most relevant sample regions in digitized blood smears. METHODS: Giemsa-stained thin blood films with P. falciparum ring-stage trophozoites (n = 27 and uninfected controls (n = 20 were digitally scanned with an oil immersion objective (0.1 µm/pixel to capture approximately 50,000 erythrocytes per sample. Parasite candidate regions were identified based on color and object size, followed by extraction of image features (local binary patterns, local contrast and Scale-invariant feature transform descriptors used as input to a support vector machine classifier. The classifier was trained on digital slides from ten patients and validated on six samples. RESULTS: The diagnostic accuracy was tested on 31 samples (19 infected and 12 controls. From each digitized area of a blood smear, a panel with the 128 most probable parasite candidate regions was generated. Two expert microscopists were asked to visually inspect the panel on a tablet computer and to judge whether the patient was infected with P. falciparum. The method achieved a diagnostic sensitivity and specificity of 95% and 100% as well as 90% and 100% for the two readers respectively using the diagnostic tool. Parasitemia was separately calculated by the automated system and the correlation coefficient between manual and automated parasitemia counts was 0.97. CONCLUSION: We developed a decision support system for detecting malaria parasites using a computer vision algorithm combined with visualization of sample areas with the highest probability of malaria infection. The system provides a novel method for blood smear screening with a significantly reduced need for

Color Vision in Aniridia.

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Pedersen, Hilde R; Hagen, Lene A; Landsend, Erlend C S; Gilson, Stuart J; Utheim, Øygunn A; Utheim, Tor P; Neitz, Maureen; Baraas, Rigmor C

2018-04-01

To assess color vision and its association with retinal structure in persons with congenital aniridia. We included 36 persons with congenital aniridia (10-66 years), and 52 healthy, normal trichromatic controls (10-74 years) in the study. Color vision was assessed with Hardy-Rand-Rittler (HRR) pseudo-isochromatic plates (4th ed., 2002); Cambridge Color Test and a low-vision version of the Color Assessment and Diagnosis test (CAD-LV). Cone-opsin genes were analyzed to confirm normal versus congenital color vision deficiencies. Visual acuity and ocular media opacities were assessed. The central 30° of both eyes were imaged with the Heidelberg Spectralis OCT2 to grade the severity of foveal hypoplasia (FH, normal to complete: 0-4). Five participants with aniridia had cone opsin genes conferring deutan color vision deficiency and were excluded from further analysis. Of the 31 with aniridia and normal opsin genes, 11 made two or more red-green (RG) errors on HRR, four of whom also made yellow-blue (YB) errors; one made YB errors only. A total of 19 participants had higher CAD-LV RG thresholds, of which eight also had higher CAD-LV YB thresholds, than normal controls. In aniridia, the thresholds were higher along the RG than the YB axis, and those with a complete FH had significantly higher RG thresholds than those with mild FH (P = 0.038). Additional increase in YB threshold was associated with secondary ocular pathology. Arrested foveal formation and associated alterations in retinal processing are likely to be the primary reason for impaired red-green color vision in aniridia.

Effect of elimination of nitrogen and/or hypoxia or restricted visual environment on color vision and range of accommodation

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Wolbarsht, M. L.; White, C. W.; Anderson, W. B., Jr.

1973-01-01

The effects upon range of accommodation and color vision of reduced atmospheric pressure, at partial and complete elimination of nitrogen, of hypoxia, and of exposure for varying periods of time to restricted visual environment, have been studied alone or in various combinations. Measurements were made on the electroretinogram, the electrooculogram, and the diameter of the retinal vessels as an indicator of blood flow to the retina at the time of total elimination of nitrogen. An objective method was used to test range of accommodation. In the color vision test the flicker colors of a Benham's top were matched with a colorimeter.

An amodal shared resource model of language-mediated visual attention

Directory of Open Access Journals (Sweden)

Alastair Charles Smith

2013-08-01

Full Text Available Language-mediated visual attention describes the interaction of two fundamental components of the human cognitive system, language and vision. Within this paper we present an amodal shared resource model of language-mediated visual attention that offers a description of the information and processes involved in this complex multimodal behaviour and a potential explanation for how this ability is acquired. We demonstrate that the model is not only sufficient to account for the experimental effects of Visual World Paradigm studies but also that these effects are emergent properties of the architecture of the model itself, rather than requiring separate information processing channels or modular processing systems. The model provides an explicit description of the connection between the modality-specific input from language and vision and the distribution of eye gaze in language mediated visual attention. The paper concludes by discussing future applications for the model, specifically its potential for investigating the factors driving observed individual differences in language mediated eye gaze.

An Enduring Dialogue between Computational and Empirical Vision.

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Martinez-Conde, Susana; Macknik, Stephen L; Heeger, David J

2018-04-01

In the late 1970s, key discoveries in neurophysiology, psychophysics, computer vision, and image processing had reached a tipping point that would shape visual science for decades to come. David Marr and Ellen Hildreth's 'Theory of edge detection', published in 1980, set out to integrate the newly available wealth of data from behavioral, physiological, and computational approaches in a unifying theory. Although their work had wide and enduring ramifications, their most important contribution may have been to consolidate the foundations of the ongoing dialogue between theoretical and empirical vision science. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using perturbations to identify the brain circuits underlying active vision.

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Wurtz, Robert H

2015-09-19

The visual and oculomotor systems in the brain have been studied extensively in the primate. Together, they can be regarded as a single brain system that underlies active vision--the normal vision that begins with visual processing in the retina and extends through the brain to the generation of eye movement by the brainstem. The system is probably one of the most thoroughly studied brain systems in the primate, and it offers an ideal opportunity to evaluate the advantages and disadvantages of the series of perturbation techniques that have been used to study it. The perturbations have been critical in moving from correlations between neuronal activity and behaviour closer to a causal relation between neuronal activity and behaviour. The same perturbation techniques have also been used to tease out neuronal circuits that are related to active vision that in turn are driving behaviour. The evolution of perturbation techniques includes ablation of both cortical and subcortical targets, punctate chemical lesions, reversible inactivations, electrical stimulation, and finally the expanding optogenetic techniques. The evolution of perturbation techniques has supported progressively stronger conclusions about what neuronal circuits in the brain underlie active vision and how the circuits themselves might be organized.

8th International Conference on Robotic, Vision, Signal Processing & Power Applications

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Mustaffa, Mohd

2014-01-01

The proceeding is a collection of research papers presented, at the 8th International Conference on Robotics, Vision, Signal Processing and Power Applications (ROVISP 2013), by researchers, scientists, engineers, academicians as well as industrial professionals from all around the globe. The topics of interest are as follows but are not limited to: • Robotics, Control, Mechatronics and Automation • Vision, Image, and Signal Processing • Artificial Intelligence and Computer Applications • Electronic Design and Applications • Telecommunication Systems and Applications • Power System and Industrial Applications  

78 FR 12815 - Qualification of Drivers; Exemption Applications; Vision

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2013-02-25

.... The best corrected visual acuity in his right eye is light perception, and in his left eye, 20/20.... Lifelong. Stable. Visual fields WNL. Color WNL. No contraindications for commercial driving.'' Mr. Clark... color vision, 180 degrees of peripheral vision, no medical contraindication to commercial truck driving...

Vision related quality of life in patients with type 2 diabetes in the EUROCONDOR trial.

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Trento, Marina; Durando, Olga; Lavecchia, Sonia; Charrier, Lorena; Cavallo, Franco; Costa, Miguel Angelo; Hernández, Cristina; Simó, Rafael; Porta, Massimo

2017-07-01

To evaluate vision related quality of life in the patients enrolled in The European Consortium for the Early Treatment of Diabetic Retinopathy, a clinical trial on prevention of diabetic retinopathy. Four-hundred-forty-nine patients, 153 women, with type 2 Diabetes and no or mild diabetic retinopathy were enrolled in a 2-year multicenter randomized controlled trial. The 25-item National Eye Institute Visual Functioning Questionnaire was used to explore 12 subscales of vision related quality of life. The patients were 62.8 ± 6.7 years old and had 11.1 ± 5.6 years known disease duration. Diabetic retinopathy was absent in 193 (43.0 %) and mild in 256 (57.0 %). Patients without diabetic retinopathy were older, had shorter diabetes duration and used less insulin and glucose-lowering agents but did not differ by gender, best corrected visual acuity or any subscale, except vision specific mental health and vision specific role difficulties. Patients with reduced retinal thickness at the ganglion cell layer (n = 36) did not differ for diabetic retinopathy but were older, had lower best corrected visual acuity and worse scores for ocular pain, color vision and peripheral vision. On multivariable analysis, worse scores for general vision remained associated with reduced retinal thickness, diabetes duration and best corrected visual acuity, and scores for visual specific mental health with diabetic retinopathy and lower best corrected visual acuity. Visual specific role difficulties were only associated with reduced best corrected visual acuity. Scores for driving decreased among females, with worsening of Hemoglobin A1c and best corrected visual acuity. Color vision depended only on reduced retinal thickness, and peripheral vision on both reduced thickness and best corrected visual acuity. The National Eye Institute Visual Functioning Questionnaire could detect subtle changes in patients' perception of visual function, despite absent/minimal diabetic

Image understanding systems based on the unifying representation of perceptual and conceptual information and the solution of mid-level and high-level vision problems

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Kuvychko, Igor

2001-10-01

Vision is a part of a larger information system that converts visual information into knowledge structures. These structures drive vision process, resolving ambiguity and uncertainty via feedback, and provide image understanding, that is an interpretation of visual information in terms of such knowledge models. A computer vision system based on such principles requires unifying representation of perceptual and conceptual information. Computer simulation models are built on the basis of graphs/networks. The ability of human brain to emulate similar graph/networks models is found. That means a very important shift of paradigm in our knowledge about brain from neural networks to the cortical software. Starting from the primary visual areas, brain analyzes an image as a graph-type spatial structure. Primary areas provide active fusion of image features on a spatial grid-like structure, where nodes are cortical columns. The spatial combination of different neighbor features cannot be described as a statistical/integral characteristic of the analyzed region, but uniquely characterizes such region itself. Spatial logic and topology naturally present in such structures. Mid-level vision processes like clustering, perceptual grouping, multilevel hierarchical compression, separation of figure from ground, etc. are special kinds of graph/network transformations. They convert low-level image structure into the set of more abstract ones, which represent objects and visual scene, making them easy for analysis by higher-level knowledge structures. Higher-level vision phenomena like shape from shading, occlusion, etc. are results of such analysis. Such approach gives opportunity not only to explain frequently unexplainable results of the cognitive science, but also to create intelligent computer vision systems that simulate perceptional processes in both what and where visual pathways. Such systems can open new horizons for robotic and computer vision industries.

Self-Grounded Vision: Hand Ownership Modulates Visual Location through Cortical β and γ Oscillations.

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Faivre, Nathan; Dönz, Jonathan; Scandola, Michele; Dhanis, Herberto; Bello Ruiz, Javier; Bernasconi, Fosco; Salomon, Roy; Blanke, Olaf

2017-01-04

Vision is known to be shaped by context, defined by environmental and bodily signals. In the Taylor illusion, the size of an afterimage projected on one's hand changes according to proprioceptive signals conveying hand position. Here, we assessed whether the Taylor illusion does not just depend on the physical hand position, but also on bodily self-consciousness as quantified through illusory hand ownership. Relying on the somatic rubber hand illusion, we manipulated hand ownership, such that participants embodied a rubber hand placed next to their own hand. We found that an afterimage projected on the participant's hand drifted depending on illusory ownership between the participants' two hands, showing an implication of self-representation during the Taylor illusion. Oscillatory power analysis of electroencephalographic signals showed that illusory hand ownership was stronger in participants with stronger α suppression over left sensorimotor cortex, whereas the Taylor illusion correlated with higher β/γ power over frontotemporal regions. Higher γ connectivity between left sensorimotor and inferior parietal cortex was also found during illusory hand ownership. These data show that afterimage drifts in the Taylor illusion do not only depend on the physical hand position but also on subjective ownership, which itself is based on the synchrony of somatosensory signals from the two hands. The effect of ownership on afterimage drifts is associated with β/γ power and γ connectivity between frontoparietal regions and the visual cortex. Together, our results suggest that visual percepts are not only influenced by bodily context but are self-grounded, mapped on a self-referential frame. Vision is influenced by the body: in the Taylor illusion, the size of an afterimage projected on one's hand changes according to tactile and proprioceptive signals conveying hand position. Here, we report a new phenomenon revealing that the perception of afterimages depends not only

Optoelectronic vision

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Ren, Chunye; Parel, Jean-Marie A.

1993-06-01

Scientists have searched every discipline to find effective methods of treating blindness, such as using aids based on conversion of the optical image, to auditory or tactile stimuli. However, the limited performance of such equipment and difficulties in training patients have seriously hampered practical applications. A great edification has been given by the discovery of Foerster (1929) and Krause & Schum (1931), who found that the electrical stimulation of the visual cortex evokes the perception of a small spot of light called `phosphene' in both blind and sighted subjects. According to this principle, it is possible to invite artificial vision by using stimulation with electrodes placed on the vision neural system, thereby developing a prosthesis for the blind that might be of value in reading and mobility. In fact, a number of investigators have already exploited this phenomena to produce a functional visual prosthesis, bringing about great advances in this area.

Computational vision

CERN Document Server

Wechsler, Harry

1990-01-01

The book is suitable for advanced courses in computer vision and image processing. In addition to providing an overall view of computational vision, it contains extensive material on topics that are not usually covered in computer vision texts (including parallel distributed processing and neural networks) and considers many real applications.

78 FR 4478 - Federal Employees Dental and Vision Insurance Program: Application Process for Contract Awards

Science.gov (United States)

2013-01-22

... process is being changed to be in line with the process used for the Federal Employees Health Benefits... OFFICE OF PERSONNEL MANAGEMENT Federal Employees Dental and Vision Insurance Program: Application... Process for Federal Employees Dental and Vision Insurance Program Contract Awards. SUMMARY: The U. S...

[The influence of IOL implantation on visual acuity, contrast sensitivity and colour vision 2 and 4 months after cataract surgery].

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Ventruba, J

2006-04-01

To assess the change in visual acuity, contrast sensitivity and colour vision in relation to the time after cataract surgery and to the type of implanted IOL, and to compare visual functions by patients with one and two pseudophakic eyes. 45 cataract patients were examined before and then 2 and 4 month after the cataract surgery. Visual acuity (VA) was tested on logMAR optotype chart with Landolt rings, contrast sensitivity (CS) was tested on the Pelli-Robson chart and the SWCT chart. For colour vision (CV) testing, the standard Farnsworth D-15 test and the desaturated Lanthony D-15 test were used. The patients were divided into two groups--a group with one pseudophakic eye and a group with two pseudophakic eyes, and also according to the type of IOL--PMMA or hydrophobic acrylate that had been implanted. Control group was composed of phakic subjects with no ocular pathology. After the cataract surgery, in both groups there was a significant improvement in monocular and binocular VA (p test (p test (p tested by means of psychophysical methods of VA, CS and CV significantly improve and are stable 2 month after the surgery. The second eye surgery improves binocular visual functions the level of which doesn't differ from that of normal phakic subjects. There was no influence of the type of IOL on final state of VA, CS or CV.

Hypnosis-associated blue-tinted vision: a case report

Directory of Open Access Journals (Sweden)

Savedoff Aaron D

2005-12-01

Full Text Available Abstract Background Self-hypnosis has been taught routinely at the SUNY Upstate Medical University for treatment of pulmonary symptoms thought to be amenable to psychological therapy. While using hypnosis for relaxation, four individuals, including a patient with cystic fibrosis, reported development of blue-tinted vision. Based on a search of the literature, we believe this is the first published report of hypnosis-associated blue-tinted vision. Case presentation The patient reported blue-tinted vision when he used hypnosis on an almost daily basis for seven years. The visual change typically occurred when he was relaxed. Moreover, a concurrent erection in the absence of sexual thoughts usually was present. The other three individuals reported blue-tinted vision after learning how to use hypnosis for relaxation as part of a group hypnosis instruction. Conclusion The blue-tinted vision experienced by the individuals in this report may be the result of an hypnosis-induced primary change in cognitive processing. Additionally, as the relaxing effect of hypnosis can be associated with a reduction in blood pressure and increased blood flow, hypnosis-associated blue-tinted vision also may be related to retinal vasodilation.

Computer vision in control systems

CERN Document Server

Jain, Lakhmi

2015-01-01

Volume 1 : This book is focused on the recent advances in computer vision methodologies and technical solutions using conventional and intelligent paradigms. The Contributions include: ·         Morphological Image Analysis for Computer Vision Applications. ·         Methods for Detecting of Structural Changes in Computer Vision Systems. ·         Hierarchical Adaptive KL-based Transform: Algorithms and Applications. ·         Automatic Estimation for Parameters of Image Projective Transforms Based on Object-invariant Cores. ·         A Way of Energy Analysis for Image and Video Sequence Processing. ·         Optimal Measurement of Visual Motion Across Spatial and Temporal Scales. ·         Scene Analysis Using Morphological Mathematics and Fuzzy Logic. ·         Digital Video Stabilization in Static and Dynamic Scenes. ·         Implementation of Hadamard Matrices for Image Processing. ·         A Generalized Criterion ...

New, Patented Technique for Naturally Restoring Healthy Vision

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Anganes, Andrew A.; McLeod, Roger David; Machado, Milena

2009-05-01

The patented NATUROPTIC METHOD FOR RESTORING HEALTHY VISION claims to be a novel teaching method for safely and naturally improving vision. It is a simple tutoring process designed to work quickly, requiring only a minimal number of sessions for improvement. We investigated these claims, implementing Naturoptics for safe recovery of vision, ourselves, over a period of time. Research was conducted at off campus locations, mentored by the creator of the Naturoptic Method. We assessed our initial visual acuity and subsequent progress, using standard Snellen Eye Charts. Our research is designed to document successive improvements in vision, and to assess our potential for teaching the method. Naturoptics' Board encourages work-study memorial awards for students. They are: ``The David Matthew McLeod Memorial Award,'' or ``The Kaan Balam Matagamon Memorial Award,'' with net earnings shared by the designees, academic entities, the American Indians in Science and Engineering Society, AISES, or charity. The Board requires awardees, students, and associated entities, to sign non-disclosure agreements.

What are the visual features underlying rapid object recognition?

Directory of Open Access Journals (Sweden)

Sébastien M Crouzet

2011-11-01

Full Text Available Research progress in machine vision has been very significant in recent years. Robust face detection and identification algorithms are already readily available to consumers, and modern computer vision algorithms for generic object recognition are now coping with the richness and complexity of natural visual scenes. Unlike early vision models of object recognition that emphasized the role of figure-ground segmentation and spatial information between parts, recent successful approaches are based on the computation of loose collections of image features without prior segmentation or any explicit encoding of spatial relations. While these models remain simplistic models of visual processing, they suggest that, in principle, bottom-up activation of a loose collection of image features could support the rapid recognition of natural object categories and provide an initial coarse visual representation before more complex visual routines and attentional mechanisms take place. Focusing on biologically-plausible computational models of (bottom-up pre-attentive visual recognition, we review some of the key visual features that have been described in the literature. We discuss the consistency of these feature-based representations with classical theories from visual psychology and test their ability to account for human performance on a rapid object categorization task.

Functional Vision Observation. Technical Assistance Paper.

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Florida State Dept. of Education, Tallahassee. Bureau of Education for Exceptional Students.

Technical assistance is provided concerning documentation of functional vision loss for Florida students with visual impairments. The functional vision observation should obtain enough information for determination of special service eligibility. The observation is designed to supplement information on the medical eye examination, and is conducted…

Eyesight quality and Computer Vision Syndrome.

Science.gov (United States)

Bogdănici, Camelia Margareta; Săndulache, Diana Elena; Nechita, Corina Andreea

2017-01-01

The aim of the study was to analyze the effects that gadgets have on eyesight quality. A prospective observational study was conducted from January to July 2016, on 60 people who were divided into two groups: Group 1 - 30 middle school pupils with a mean age of 11.9 ± 1.86 and Group 2 - 30 patients evaluated in the Ophthalmology Clinic, "Sf. Spiridon" Hospital, Iași, with a mean age of 21.36 ± 7.16 years. The clinical parameters observed were the following: visual acuity (VA), objective refraction, binocular vision (BV), fusional amplitude (FA), Schirmer's test. A questionnaire was also distributed, which contained 8 questions that highlighted the gadget's impact on the eyesight. The use of different gadgets, such as computer, laptops, mobile phones or other displays become part of our everyday life and people experience a variety of ocular symptoms or vision problems related to these. Computer Vision Syndrome (CVS) represents a group of visual and extraocular symptoms associated with sustained use of visual display terminals. Headache, blurred vision, and ocular congestion are the most frequent manifestations determined by the long time use of gadgets. Mobile phones and laptops are the most frequently used gadgets. People who use gadgets for a long time have a sustained effort for accommodation. A small amount of refractive errors (especially myopic shift) was objectively recorded by various studies on near work. Dry eye syndrome could also be identified, and an improvement of visual comfort could be observed after the instillation of artificial tears drops. Computer Vision Syndrome is still under-diagnosed, and people should be made aware of the bad effects the prolonged use of gadgets has on eyesight.

Vision in laboratory rodents-Tools to measure it and implications for behavioral research.

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Leinonen, Henri; Tanila, Heikki

2017-07-29

Mice and rats are nocturnal mammals and their vision is specialized for detection of motion and contrast in dim light conditions. These species possess a large proportion of UV-sensitive cones in their retinas and the majority of their optic nerve axons target superior colliculus rather than visual cortex. Therefore, it was a widely held belief that laboratory rodents hardly utilize vision during day-time behavior. This dogma is being questioned as accumulating evidence suggests that laboratory rodents are able to perform complex visual functions, such as perceiving subjective contours, and that declined vision may affect their performance in many behavioral tasks. For instance, genetic engineering may have unexpected consequences on vision as mouse models of Alzheimer's and Huntington's diseases have declined visual function. Rodent vision can be tested in numerous ways using operant training or reflex-based behavioral tasks, or alternatively using electrophysiological recordings. In this article, we will first provide a summary of visual system and explain its characteristics unique to rodents. Then, we present well-established techniques to test rodent vision, with an emphasis on pattern vision: visual water test, optomotor reflex test, pattern electroretinography and pattern visual evoked potentials. Finally, we highlight the importance of visual phenotyping in rodents. As the number of genetically engineered rodent models and volume of behavioral testing increase simultaneously, the possibility of visual dysfunctions needs to be addressed. Neglect in this matter potentially leads to crude biases in the field of neuroscience and beyond. Copyright © 2017 Elsevier B.V. All rights reserved.

Binocular depth processing in the ventral visual pathway.

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Verhoef, Bram-Ernst; Vogels, Rufin; Janssen, Peter

2016-06-19

One of the most powerful forms of depth perception capitalizes on the small relative displacements, or binocular disparities, in the images projected onto each eye. The brain employs these disparities to facilitate various computations, including sensori-motor transformations (reaching, grasping), scene segmentation and object recognition. In accordance with these different functions, disparity activates a large number of regions in the brain of both humans and monkeys. Here, we review how disparity processing evolves along different regions of the ventral visual pathway of macaques, emphasizing research based on both correlational and causal techniques. We will discuss the progression in the ventral pathway from a basic absolute disparity representation to a more complex three-dimensional shape code. We will show that, in the course of this evolution, the underlying neuronal activity becomes progressively more bound to the global perceptual experience. We argue that these observations most probably extend beyond disparity processing per se, and pertain to object processing in the ventral pathway in general. We conclude by posing some important unresolved questions whose answers may significantly advance the field, and broaden its scope.This article is part of the themed issue 'Vision in our three-dimensional world'. © 2016 The Author(s).

Image processing analysis of traditional Gestalt vision experiments

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McCann, John J.

2002-06-01

In the late 19th century, the Gestalt Psychology rebelled against the popular new science of Psychophysics. The Gestalt revolution used many fascinating visual examples to illustrate that the whole is greater than the sum of all the parts. Color constancy was an important example. The physical interpretation of sensations and their quantification by JNDs and Weber fractions were met with innumerable examples in which two 'identical' physical stimuli did not look the same. The fact that large changes in the color of the illumination failed to change color appearance in real scenes demanded something more than quantifying the psychophysical response of a single pixel. The debates continues today with proponents of both physical, pixel-based colorimetry and perceptual, image- based cognitive interpretations. Modern instrumentation has made colorimetric pixel measurement universal. As well, new examples of unconscious inference continue to be reported in the literature. Image processing provides a new way of analyzing familiar Gestalt displays. Since the pioneering experiments by Fergus Campbell and Land, we know that human vision has independent spatial channels and independent color channels. Color matching data from color constancy experiments agrees with spatial comparison analysis. In this analysis, simple spatial processes can explain the different appearances of 'identical' stimuli by analyzing the multiresolution spatial properties of their surrounds. Benary's Cross, White's Effect, the Checkerboard Illusion and the Dungeon Illusion can all be understood by the analysis of their low-spatial-frequency components. Just as with color constancy, these Gestalt images are most simply described by the analysis of spatial components. Simple spatial mechanisms account for the appearance of 'identical' stimuli in complex scenes. It does not require complex, cognitive processes to calculate appearances in familiar Gestalt experiments.

Vision in water.

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Atchison, David A; Valentine, Emma L; Gibson, Georgina; Thomas, Hannah R; Oh, Sera; Pyo, Young Ah; Lacherez, Philippe; Mathur, Ankit

2013-09-06

The purpose of this study is to determine visual performance in water, including the influence of pupil size. The water environment was simulated by placing goggles filled with saline in front of the eyes with apertures placed at the front of the goggles. Correction factors were determined for the different magnification under this condition in order to estimate vision in water. Experiments were conducted on letter visual acuity (seven participants), grating resolution (eight participants), and grating contrast sensitivity (one participant). For letter acuity, mean loss of vision in water, compared to corrected vision in air, varied between 1.1 log min of arc resolution (logMAR) for a 1 mm aperture to 2.2 logMAR for a 7 mm aperture. The vision in min of arc was described well by a linear relationship with pupil size. For grating acuity, mean loss varied between 1.1 logMAR for a 2 mm aperture to 1.2 logMAR for a 6 mm aperture. Contrast sensitivity for a 2 mm aperture deteriorated as spatial frequency increased with a 2 log unit loss by 3 c/°. Superimposed on this deterioration were depressions (notches) in sensitivity with the first three notches occurring at 0.45, 0.8, and 1.3 c/° with estimates for water of 0.39, 0.70, and 1.13 c/°. In conclusion, vision in water is poor. It becomes worse as pupil size increases, but the effects are much more marked for letter targets than for grating targets.

Vision as subjective perception; La vision, une perception subjective

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Reppas, J.B. [Harvard Univ., Cambridge, MA (United States). Biological Labs.; Dale, A.; Sereno, M.; Tootell, R.

1996-07-01

The human brain is not very different of the monkey`s one: at least, its visual cortex is organized as a similar scheme. Specialized areas in the movement analysis are found and others in the forms perception. In this work, the author tries to answer to the following questions: (1)why so many visual areas? What are exactly their role in vision? Thirteen years of experimentation have not allowed to answer to these questions. The cerebral NMR imaging gives the opportunity of understanding the subjective perception of the visual world. One step which is particularly described in this work is to know how the visual cortex reacts to the optical illusions. (O.M.).

9th International Conference on Robotics, Vision, Signal Processing & Power Applications

CERN Document Server

Iqbal, Shahid; Teoh, Soo; Mustaffa, Mohd

2017-01-01

 The proceeding is a collection of research papers presented, at the 9th International Conference on Robotics, Vision, Signal Processing & Power Applications (ROVISP 2016), by researchers, scientists, engineers, academicians as well as industrial professionals from all around the globe to present their research results and development activities for oral or poster presentations. The topics of interest are as follows but are not limited to:   • Robotics, Control, Mechatronics and Automation • Vision, Image, and Signal Processing • Artificial Intelligence and Computer Applications • Electronic Design and Applications • Telecommunication Systems and Applications • Power System and Industrial Applications • Engineering Education.

Asymmetric Attention: Visualizing the Uncertain Threat

Science.gov (United States)

2010-03-01

contrast, Bocanegra and Zeelenberg (2009) demonstrated that emotional factors can improve some components of visual processing, while actually...on a year in Afghanistan. ARMY Magazine,59, 44-54. Bocanegra, B.R., & Zeelenberg , R. (2009). Emotion improves and impairs early vision

Development of the functional vision questionnaire for children and young people with visual impairment: the FVQ_CYP.

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Tadić, Valerija; Cooper, Andrew; Cumberland, Phillippa; Lewando-Hundt, Gillian; Rahi, Jugnoo S

2013-12-01

To develop a novel age-appropriate measure of functional vision (FV) for self-reporting by visually impaired (VI) children and young people. Questionnaire development. A representative patient sample of VI children and young people aged 10 to 15 years, visual acuity of the logarithm of the minimum angle of resolution (logMAR) worse than 0.48, and a school-based (nonrandom) expert group sample of VI students aged 12 to 17 years. A total of 32 qualitative semistructured interviews supplemented by narrative feedback from 15 eligible VI children and young people were used to generate draft instrument items. Seventeen VI students were consulted individually on item relevance and comprehensibility, instrument instructions, format, and administration methods. The resulting draft instrument was piloted with 101 VI children and young people comprising a nationally representative sample, drawn from 21 hospitals in the United Kingdom. Initial item reduction was informed by presence of missing data and individual item response pattern. Exploratory factor analysis (FA) and parallel analysis (PA), and Rasch analysis (RA) were applied to test the instrument's psychometric properties. Psychometric indices and validity assessment of the Functional Vision Questionnaire for Children and Young People (FVQ_CYP). A total of 712 qualitative statements became a 56-item draft scale, capturing the level of difficulty in performing vision-dependent activities. After piloting, items were removed iteratively as follows: 11 for high percentage of missing data, 4 for skewness, and 1 for inadequate item infit and outfit values in RA, 3 having shown differential item functioning across age groups and 1 across gender in RA. The remaining 36 items showed item fit values within acceptable limits, good measurement precision and targeting, and ordered response categories. The reduced scale has a clear unidimensional structure, with all items having a high factor loading on the single factor in FA and

Armstrong Laboratory Space Visual Function Tester Program

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Oneal, Melvin R.; Task, H. Lee; Gleason, Gerald A.

1992-01-01

Viewgraphs on space visual function tester program are presented. Many astronauts and cosmonauts have commented on apparent changes in their vision while on-orbit. Comments have included descriptions of earth features and objects that would suggest enhanced distance visual acuity. In contrast, some cosmonaut observations suggest a slight loss in their object discrimination during initial space flight. Astronauts have also mentioned a decreased near vision capability that did not recover to normal until return to earth. Duntley space vision experiment, USSR space vision experiments, and visual function testers are described.

Prevalence and causes of low vision and blindness in Baotou

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Zhang, Guisen; Li, Yan; Teng, Xuelong; Wu, Qiang; Gong, Hui; Ren, Fengmei; Guo, Yuxia; Liu, Lei; Zhang, Han

2016-01-01

Abstract The aim of this study was to investigate the prevalence and causes of low vision and blindness in Baotou, Inner Mongolia. A cross-sectional study was carried out. Multistage sampling was used to select samples. The visual acuity was estimated using LogMAR and corrected by pinhole as best-corrected visual acuity. There were 7000 samples selected and 5770 subjects included in this investigation. The overall bilateral prevalence rates of low vision and blindness were 3.66% (95% CI: 3.17–4.14) and 0.99% (95% CI: 0.73–1.24), respectively. The prevalence of bilateral low vision, blindness, and visual impairment increased with age and decreased with education level. The main leading cause of low vision and blindness was cataract. Diabetic retinopathy and age-related macular degeneration were found to be the second leading causes of blindness in Baotou. The low vision and blindness were more prevalent in elderly people and subjects with low education level in Baotou. Cataract was the main cause for visual impairment and more attention should be paid to fundus diseases. In order to prevent blindness, much more eye care programs should be established. PMID:27631267

Radical “Visual Capture” Observed in a Patient with Severe Visual Agnosia

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Takaiwa, Akiko; Yoshimura, Hirokazu; Abe, Hirofumi; Terai, Satoshi

2003-01-01

We report the case of a 79-year-old female with visual agnosia due to brain infarction in the left posterior cerebral artery. She could recognize objects used in daily life rather well by touch (the number of objects correctly identified was 16 out of 20 presented objects), but she could not recognize them as well by vision (6 out of 20). In this case, it was expected that she would recognize them well when permitted to use touch and vision simultaneously. Our patient, however, performed poorly, producing 5 correct answers out of 20 in the Vision-and-Touch condition. It would be natural to think that visual capture functions when vision and touch provide contradictory information on concrete positions and shapes. However, in the present case, it functioned in spite of the visual deficit in recognizing objects. This should be called radical visual capture. By presenting detailed descriptions of her symptoms and neuropsychological and neuroradiological data, we clarify the characteristics of this type of capture. PMID:12719638

Radical “Visual Capture” Observed in a Patient with Severe Visual Agnosia

Directory of Open Access Journals (Sweden)

Akiko Takaiwa

2003-01-01

Full Text Available We report the case of a 79-year-old female with visual agnosia due to brain infarction in the left posterior cerebral artery. She could recognize objects used in daily life rather well by touch (the number of objects correctly identified was 16 out of 20 presented objects, but she could not recognize them as well by vision (6 out of 20. In this case, it was expected that she would recognize them well when permitted to use touch and vision simultaneously. Our patient, however, performed poorly, producing 5 correct answers out of 20 in the Vision-and-Touch condition. It would be natural to think that visual capture functions when vision and touch provide contradictory information on concrete positions and shapes. However, in the present case, it functioned in spite of the visual deficit in recognizing objects. This should be called radical visual capture. By presenting detailed descriptions of her symptoms and neuropsychological and neuroradiological data, we clarify the characteristics of this type of capture.

Evidence for RPE65-independent vision in the cone-dominated zebrafish retina.

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Schonthaler, Helia B; Lampert, Johanna M; Isken, Andrea; Rinner, Oliver; Mader, Andreas; Gesemann, Matthias; Oberhauser, Vitus; Golczak, Marcin; Biehlmaier, Oliver; Palczewski, Krzysztof; Neuhauss, Stephan C F; von Lintig, Johannes

2007-10-01

An enzyme-based cyclic pathway for trans to cis isomerization of the chromophore of visual pigments (11-cis-retinal) is intrinsic to vertebrate cone and rod vision. This process, called the visual cycle, is mostly characterized in rod-dominated retinas and essentially depends on RPE65, an all-trans to 11-cis-retinoid isomerase. Here we analysed the role of RPE65 in zebrafish, a species with a cone-dominated retina. We cloned zebrafish RPE65 and showed that its expression coincided with photoreceptor development. Targeted gene knockdown of RPE65 resulted in morphologically altered rod outer segments and overall reduced 11-cis-retinal levels. Cone vision of RPE65-deficient larvae remained functional as demonstrated by behavioural tests and by metabolite profiling for retinoids. Furthermore, all-trans retinylamine, a potent inhibitor of the rod visual cycle, reduced 11-cis-retinal levels of control larvae to a similar extent but showed no additive effects in RPE65-deficient larvae. Thus, our study of zebrafish provides in vivo evidence for the existence of an RPE65-independent pathway for the regeneration of 11-cis-retinal for cone vision.

Association between changes in visual acuity and vision-related quality of life in Japanese patients with low vision.

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Yanagisawa, Mieko; Kato, Satoshi; Kunimatsu, Shiho; Kobayashi, Megumi; Ochiai, Makiko

2011-01-01

To investigate the association between vision-related quality of life (VRQOL) and changes in visual acuity (VA). We examined the VA in 100 patients for > 1 year and evaluated the degree of its impact on VRQOL using the National Eye Institute Visual Function (VF) Questionnaire (VFQ-25; Japanese version). Before determining VFQ-25, we monitored the changes in VA in these patients for 1 year and classified them into the following two groups depending on VA changes. Patients exhibiting a decline of > 3 steps in VA, as assessed by the logarithm of the minimum angle of resolution scale, were placed in the 'decline' group (47.0%) and patients exhibiting no change in VA were placed in the 'no change' group (53.0%). We compared the VFQ-25 scores between both groups in all patients with glaucoma (GLA) and macular degeneration (MD). The total score of the decline was 34.9 ± 13.6 and that of the no change group was 44.6 ± 13.9: the difference in the scores between both groups was statistically significant (p = 0.006). Similar results were obtained for patients with GLA and MD (p = 0.007 and 0.003, respectively). VRQOL differed between patients with constant VA and those with reduced VA, even though VA values were equal at a certain time point. Copyright © 2010 S. Karger AG, Basel.

Pre-attentive and attentive vision module

NARCIS (Netherlands)

Nyamsuren, Enkhbold; Taatgen, Niels A.

This paper introduces a new vision module, called PAAV, developed for the cognitive architecture ACT-R. Unlike ACT-R's default vision module that was originally developed for top-down perception only, PAAV was designed to model a wide range of tasks, such as visual search and scene viewing, where

Visual processing speed in old age.

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Habekost, Thomas; Vogel, Asmus; Rostrup, Egill; Bundesen, Claus; Kyllingsbaek, Søren; Garde, Ellen; Ryberg, Charlotte; Waldemar, Gunhild

2013-04-01

Mental speed is a common concept in theories of cognitive aging, but it is difficult to get measures of the speed of a particular psychological process that are not confounded by the speed of other processes. We used Bundesen's (1990) Theory of Visual Attention (TVA) to obtain specific estimates of processing speed in the visual system controlled for the influence of response latency and individual variations of the perception threshold. A total of 33 non-demented old people (69-87 years) were tested for the ability to recognize briefly presented letters. Performance was analyzed by the TVA model. Visual processing speed decreased approximately linearly with age and was on average halved from 70 to 85 years. Less dramatic aging effects were found for the perception threshold and the visual apprehension span. In the visual domain, cognitive aging seems to be most clearly related to reductions in processing speed. © 2012 The Authors. Scandinavian Journal of Psychology © 2012 The Scandinavian Psychological Associations.

Vision Systems with the Human in the Loop

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Bauckhage, Christian; Hanheide, Marc; Wrede, Sebastian; Käster, Thomas; Pfeiffer, Michael; Sagerer, Gerhard

2005-12-01

The emerging cognitive vision paradigm deals with vision systems that apply machine learning and automatic reasoning in order to learn from what they perceive. Cognitive vision systems can rate the relevance and consistency of newly acquired knowledge, they can adapt to their environment and thus will exhibit high robustness. This contribution presents vision systems that aim at flexibility and robustness. One is tailored for content-based image retrieval, the others are cognitive vision systems that constitute prototypes of visual active memories which evaluate, gather, and integrate contextual knowledge for visual analysis. All three systems are designed to interact with human users. After we will have discussed adaptive content-based image retrieval and object and action recognition in an office environment, the issue of assessing cognitive systems will be raised. Experiences from psychologically evaluated human-machine interactions will be reported and the promising potential of psychologically-based usability experiments will be stressed.

Statistical regularities in art: Relations with visual coding and perception.

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Graham, Daniel J; Redies, Christoph

2010-07-21

Since at least 1935, vision researchers have used art stimuli to test human response to complex scenes. This is sensible given the "inherent interestingness" of art and its relation to the natural visual world. The use of art stimuli has remained popular, especially in eye tracking studies. Moreover, stimuli in common use by vision scientists are inspired by the work of famous artists (e.g., Mondrians). Artworks are also popular in vision science as illustrations of a host of visual phenomena, such as depth cues and surface properties. However, until recently, there has been scant consideration of the spatial, luminance, and color statistics of artwork, and even less study of ways that regularities in such statistics could affect visual processing. Furthermore, the relationship between regularities in art images and those in natural scenes has received little or no attention. In the past few years, there has been a concerted effort to study statistical regularities in art as they relate to neural coding and visual perception, and art stimuli have begun to be studied in rigorous ways, as natural scenes have been. In this minireview, we summarize quantitative studies of links between regular statistics in artwork and processing in the visual stream. The results of these studies suggest that art is especially germane to understanding human visual coding and perception, and it therefore warrants wider study. Copyright 2010 Elsevier Ltd. All rights reserved.

Latency in Visionic Systems: Test Methods and Requirements

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Bailey, Randall E.; Arthur, J. J., III; Williams, Steven P.; Kramer, Lynda J.

2005-01-01

A visionics device creates a pictorial representation of the external scene for the pilot. The ultimate objective of these systems may be to electronically generate a form of Visual Meteorological Conditions (VMC) to eliminate weather or time-of-day as an operational constraint and provide enhancement over actual visual conditions where eye-limiting resolution may be a limiting factor. Empirical evidence has shown that the total system delays or latencies including the imaging sensors and display systems, can critically degrade their utility, usability, and acceptability. Definitions and measurement techniques are offered herein as common test and evaluation methods for latency testing in visionics device applications. Based upon available data, very different latency requirements are indicated based upon the piloting task, the role in which the visionics device is used in this task, and the characteristics of the visionics cockpit display device including its resolution, field-of-regard, and field-of-view. The least stringent latency requirements will involve Head-Up Display (HUD) applications, where the visionics imagery provides situational information as a supplement to symbology guidance and command information. Conversely, the visionics system latency requirement for a large field-of-view Head-Worn Display application, providing a Virtual-VMC capability from which the pilot will derive visual guidance, will be the most stringent, having a value as low as 20 msec.

Predicting Vision-Related Disability in Glaucoma.

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Abe, Ricardo Y; Diniz-Filho, Alberto; Costa, Vital P; Wu, Zhichao; Medeiros, Felipe A

2018-01-01

To present a new methodology for investigating predictive factors associated with development of vision-related disability in glaucoma. Prospective, observational cohort study. Two hundred thirty-six patients with glaucoma followed up for an average of 4.3±1.5 years. Vision-related disability was assessed by the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) at baseline and at the end of follow-up. A latent transition analysis model was used to categorize NEI VFQ-25 results and to estimate the probability of developing vision-related disability during follow-up. Patients were tested with standard automated perimetry (SAP) at 6-month intervals, and evaluation of rates of visual field change was performed using mean sensitivity (MS) of the integrated binocular visual field. Baseline disease severity, rate of visual field loss, and duration of follow-up were investigated as predictive factors for development of disability during follow-up. The relationship between baseline and rates of visual field deterioration and the probability of vision-related disability developing during follow-up. At baseline, 67 of 236 (28%) glaucoma patients were classified as disabled based on NEI VFQ-25 results, whereas 169 (72%) were classified as nondisabled. Patients classified as nondisabled at baseline had 14.2% probability of disability developing during follow-up. Rates of visual field loss as estimated by integrated binocular MS were almost 4 times faster for those in whom disability developed versus those in whom it did not (-0.78±1.00 dB/year vs. -0.20±0.47 dB/year, respectively; P disability developing over time (odds ratio [OR], 1.34; 95% confidence interval [CI], 1.06-1.70; P = 0.013). In addition, each 0.5-dB/year faster rate of loss of binocular MS during follow-up was associated with a more than 3.5 times increase in the risk of disability developing (OR, 3.58; 95% CI, 1.56-8.23; P = 0.003). A new methodology for classification and analysis

An integrated domain specific language for post-processing and visualizing electrophysiological signals in Java.

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Strasser, T; Peters, T; Jagle, H; Zrenner, E; Wilke, R

2010-01-01

Electrophysiology of vision - especially the electroretinogram (ERG) - is used as a non-invasive way for functional testing of the visual system. The ERG is a combined electrical response generated by neural and non-neuronal cells in the retina in response to light stimulation. This response can be recorded and used for diagnosis of numerous disorders. For both clinical practice and clinical trials it is important to process those signals in an accurate and fast way and to provide the results as structured, consistent reports. Therefore, we developed a freely available and open-source framework in Java (http://www.eye.uni-tuebingen.de/project/idsI4sigproc). The framework is focused on an easy integration with existing applications. By leveraging well-established software patterns like pipes-and-filters and fluent interfaces as well as by designing the application programming interfaces (API) as an integrated domain specific language (DSL) the overall framework provides a smooth learning curve. Additionally, it already contains several processing methods and visualization features and can be extended easily by implementing the provided interfaces. In this way, not only can new processing methods be added but the framework can also be adopted for other areas of signal processing. This article describes in detail the structure and implementation of the framework and demonstrate its application through the software package used in clinical practice and clinical trials at the University Eye Hospital Tuebingen one of the largest departments in the field of visual electrophysiology in Europe.