Perception de la verticale avec Un cadre visuel solidaire de la tete: implications pour la conception des afficheurs de casques en ae’ronauflque (Perception of the Vertical With a Head-Mounted Visual Frame: Implication for the Design of Helmet-Mounted Displays in Aeronautics)

DTIC Science & Technology

2003-02-01

de celle de la tete. MWthodes Douze sujets, 9 hommes et 3 femmes, dg6s de 23 it 41 ans, se...qui donne la sensation de voir un 6cran informatique, centr6 sur l’axe interoculaire, d’une taille angulaire de 300 X 22,5’. L ’&ran virtuel apparait...inclin6s de faqon identique par rapport ýt la gravit6. Le premier essai 6tait toujours r6alis6 avec la tete droite . Ensuite, une nouvelle orientation de

Medical student and patient perceptions of quality of life associated with vision loss.

PubMed

Chaudry, Imtiaz; Brown, Gary C; Brown, Melissa M

2015-06-01

Because most medical schools in the United States and Canada require no formal ophthalmology training, the authors queried medical student and ophthalmic patients to compare their perceptions of the quality of life (QOL) associated with vision loss. Cross-sectional comparative study of consecutive medical students and patients with vision loss using a validated, reliable, time trade-off utility instrument. Consecutive Jefferson Medical College medical students (cohort 1: 145 second-year student; cohort 2: 112 third-year/fourth-year students) and 283 patients with vision loss (patient cohort). Time trade-off vision utilities with anchors of 0.0 (death) to 1.0 (normal vision permanently) were used to quantify the QOL associated with vision loss. Students were asked to assume they had: (i) mild vision loss (20/40 to 20/50 vision in the better-seeing eye), (ii) legal blindness (20/200 in the better-seeing eye), and (iii) absolute blindness (no light perception bilaterally). Mean utilities for cohort 1/cohort 2 were 0.96/0.95 (p = 0.20) for mild vision loss, 0.88/0.84 for legal blindness (p = 0.009), and 0.80/0.67 (p < 0.0001) for absolute blindness. Medical student/patient mean utilities were 0.96/0.79 (p < 0.0001) for mild vision loss, 0.85/0.62 for legal blindness (p < 0.0001), and 0.74/0.26 (p < 0.0001) for absolute blindness. Overall, medical students underestimated the QOL associated with vision loss referent to patients with vision loss by 153%-425%. Medical students dramatically underestimated the impact of vision loss on patient QOL. Clinical training slightly improved medical student perceptions. Trivialization of vision loss could result in systemic health harm, less ophthalmic research dollars, loss of the finest medical students entering ophthalmology, and overall adverse financial effects for the field. Copyright © 2015. Published by Elsevier Inc.

The Relationship between Organizational Health and Robust School Vision in Elementary Schools

ERIC Educational Resources Information Center

Korkmaz, Mehmet

2006-01-01

Teachers play an important role in developing a robust school vision. This study is aimed to find out the likely relationship between the teachers' perception of school health and a robust school vision. It has been found that there is a significant positive relationship between teachers' perceptions of organizational health and the relative…

Functional Dissociation between Perception and Action Is Evident Early in Life

ERIC Educational Resources Information Center

Hadad, Bat-Sheva; Avidan, Galia; Ganel, Tzvi

2012-01-01

The functional distinction between vision for perception and vision for action is well documented in the mature visual system. Ganel and colleagues recently provided direct evidence for this dissociation, showing that while visual processing for perception follows Weber's fundamental law of psychophysics, action violates this law. We tracked the…

The Ebbinghaus Illusion Deceives Adults but Not Young Children

ERIC Educational Resources Information Center

Doherty, Martin J.; Campbell, Nicola M.; Tsuji, Hiromi; Phillips, William A.

2010-01-01

The sensitivity of size perception to context has been used to distinguish between "vision for action" and "vision for perception", and to study cultural, psychopathological, and developmental differences in perception. The status of that evidence is much debated, however. Here we use a rigorous double dissociation paradigm based on the Ebbinghaus…

Egocentric Direction and Position Perceptions are Dissociable Based on Only Static Lane Edge Information

PubMed Central

Nakashima, Ryoichi; Iwai, Ritsuko; Ueda, Sayako; Kumada, Takatsune

2015-01-01

When observers perceive several objects in a space, at the same time, they should effectively perceive their own position as a viewpoint. However, little is known about observers’ percepts of their own spatial location based on the visual scene information viewed from them. Previous studies indicate that two distinct visual spatial processes exist in the locomotion situation: the egocentric position perception and egocentric direction perception. Those studies examined such perceptions in information rich visual environments where much dynamic and static visual information was available. This study examined these two perceptions in information of impoverished environments, including only static lane edge information (i.e., limited information). We investigated the visual factors associated with static lane edge information that may affect these perceptions. Especially, we examined the effects of the two factors on egocentric direction and position perceptions. One is the “uprightness factor” that “far” visual information is seen at upper location than “near” visual information. The other is the “central vision factor” that observers usually look at “far” visual information using central vision (i.e., foveal vision) whereas ‘near’ visual information using peripheral vision. Experiment 1 examined the effect of the “uprightness factor” using normal and inverted road images. Experiment 2 examined the effect of the “central vision factor” using normal and transposed road images where the upper half of the normal image was presented under the lower half. Experiment 3 aimed to replicate the results of Experiments 1 and 2. Results showed that egocentric direction perception is interfered with image inversion or image transposition, whereas egocentric position perception is robust against these image transformations. That is, both “uprightness” and “central vision” factors are important for egocentric direction perception, but not for egocentric position perception. Therefore, the two visual spatial perceptions about observers’ own viewpoints are fundamentally dissociable. PMID:26648895

Effects of cortical damage on binocular depth perception.

PubMed

Bridge, Holly

2016-06-19

Stereoscopic depth perception requires considerable neural computation, including the initial correspondence of the two retinal images, comparison across the local regions of the visual field and integration with other cues to depth. The most common cause for loss of stereoscopic vision is amblyopia, in which one eye has failed to form an adequate input to the visual cortex, usually due to strabismus (deviating eye) or anisometropia. However, the significant cortical processing required to produce the percept of depth means that, even when the retinal input is intact from both eyes, brain damage or dysfunction can interfere with stereoscopic vision. In this review, I examine the evidence for impairment of binocular vision and depth perception that can result from insults to the brain, including both discrete damage, temporal lobectomy and more systemic diseases such as posterior cortical atrophy.This article is part of the themed issue 'Vision in our three-dimensional world'. © 2016 The Authors.

Effects of cortical damage on binocular depth perception

PubMed Central

2016-01-01

Stereoscopic depth perception requires considerable neural computation, including the initial correspondence of the two retinal images, comparison across the local regions of the visual field and integration with other cues to depth. The most common cause for loss of stereoscopic vision is amblyopia, in which one eye has failed to form an adequate input to the visual cortex, usually due to strabismus (deviating eye) or anisometropia. However, the significant cortical processing required to produce the percept of depth means that, even when the retinal input is intact from both eyes, brain damage or dysfunction can interfere with stereoscopic vision. In this review, I examine the evidence for impairment of binocular vision and depth perception that can result from insults to the brain, including both discrete damage, temporal lobectomy and more systemic diseases such as posterior cortical atrophy. This article is part of the themed issue ‘Vision in our three-dimensional world’. PMID:27269597

Une Vision francaise de l'environnement: les mots et les choses (A French View of Environment: Words and Things)

ERIC Educational Resources Information Center

Antoine, Gerald

1978-01-01

An examination by a French lexicologist of four terms current in ecological movements: "ecologie,""environnement,""qualite de vie," and "ambiance." For each term, several French and English dictionary definitions are given and clarifying distinctions are made. In conclusion, four composite definitions are given. (Text is in French.) (AMH)

Enhancing Perceptibility of Barely Perceptible Targets

DTIC Science & Technology

1982-12-28

faster to low spatial frequencies (Breitmeyer, 1975; Tolhurst, 1975; Vassilev & Mitov , 1976;.Breitmeyer & Ganz, 1975; Watson & Nachimas, * 1977). If ground...response than those tuned to high spatial frequencies: they appear to have a shorter latency (Breitmeyer, 1975; Vassilev & Mitov , 1975; Lupp, Bauske, & Wolf...1958. Tolhurst, D. J. Sustained and transient channels in human vision. Vision Research, 1975, 15, 1151-1155. Vassilev, A., & Mitov , D. Perception

Toward a Sociology of Oceans.

PubMed

Hannigan, John

2017-02-01

Despite covering around 70 percent of the earth's surface, the ocean has long been ignored by sociology or treated as merely an extension of land-based systems. Increasingly, however, oceans are assuming a higher profile, emerging both as a new resource frontier, a medium for geopolitical rivalry and conflict, and a unique and threatened ecological hot spot. In this article, I propose a new sociological specialty area, the "sociology of oceans" to be situated at the interface between environmental sociology and traditional maritime studies. After reviewing existing sociological research on maritime topics and the consideration of (or lack of consideration) the sea by classic sociological theorists, I briefly discuss several contemporary sociological approaches to the ocean that have attracted some notice. In the final section of the paper, I make the case for a distinct sociology of oceans and briefly sketch what this might look like. One possible trajectory for creating a shared vision or common paradigm, I argue, is to draw on Deleuze and Guattari's dialectical theory of the smooth and the striated. Même s'il couvre 70% de la surface de la Terre, l'océan a été longtemps ignoré en sociologie ou traité comme une extension des systèmes terrestres. De plus en plus, toutefois, l'océan retient l'attention, en étant vu comme une nouvelle frontière en termes de ressources, un médium pour les rivalités et les conflits géopolitiques, et un lieu écologique névralgique et unique. Dans cet article, je propose une nouvelle spécialisation sociologique, la 'sociologie des océans', se situant dans l'interface entre la sociologie environnementale et les études maritimes traditionnelles. Après une recension de la recherche sociologique existante sur les sujets maritimes et la prise en compte (ou l'absence de prise en compte) de l'océan par les théoriciens de la sociologie classique, je discute brièvement quelques approches sociologiques contemporaines de l'océan ayant attiré l'attention. Dans la dernière partie de l'article, j'insiste sur le besoin d'une sociologie distincte de l'océan et je présente brièvement à quoi cela pourrait ressembler. Une voie possible pour créer une vision commune ou un paradigme, selon moi, est de s'inspirer de la théorie dialectique du lisse et du strié de Deleuze et Guattari. © 2017 Canadian Sociological Association/La Société canadienne de sociologie.

Reaching Out: Visions for a New Decade: Abstracts = La distance apprivoisee vers une nouvelle decennie: resumes des communications.

ERIC Educational Resources Information Center

Canadian Association for Distance Education, Montreal (Quebec).

This document contains a collection of 85 abstracts, of which 56 are written in English, 27 in French, and 2 in both languages. These abstracts discuss research studies, evaluation studies, needs assessments, and the advantages and disadvantages of distance education and related issues. Some of the titles are: "Activation of learning in…

Stoneflies of the genus Zwicknia Murányi, 2014 (Plecoptera: Capniidae) from western Switzerland.

PubMed

Reding, Jean-Paul G

2018-02-21

Le genre Zwicknia Murányi, de la famille des Capniidae, a récemment été proposé pour inclure Capnia bifrons (Newman), ce qui a rendu nécessaire la révision du matériel collecté en Suisse occidentale et identifié précédemment comme correspondant à cette espèce. Cette révision, qui a depuis abouti à la description d'une espèce nouvelle pour la science, Zwicknia ledoarei Reding et al., est maintenant complétée, permettant de signaler la présence de deux espèces supplémentaires, Z. bifrons et Z. westermanni Boumans Murányi, la dernière nouvelle pour la Suisse. Des informations sur la distribution, les préférences écologiques, la zoogéographie et le statut de conservation de ces espèces en Suisse occidentale sont également apportées. Finalement, une clé d'identification pour les larves et les adultes mâles des espèces précitées est proposée.

Experiences of vision impairment in Papua New Guinea: implications for blindness prevention programs.

PubMed

Burnett, Anthea; Yashadhana, Aryati; Cabrera Aguas, Maria; Hanni, Yvonne; Yu, Mitasha

2016-01-01

A person's capability to access services and achieve good eye health is influenced by their behaviours, perceptions, beliefs and experiences. As evidence from Papua New Guinea (PNG) about people's lived experience with vision impairment is limited, the purpose of the present study was to better understand the beliefs, perceptions and emotional responses to vision impairment in PNG. A qualitative study, using both purposive and convenience sampling, was undertaken to explore common beliefs and perceptions about vision impairment, as well as the emotional responses to vision impairment. In-depth interviews were undertaken with 51 adults from five provinces representing culturally and geographically diverse regions of PNG. Grounded theory was used to elicit key themes from interview data. Participants described activities of everyday life impacted by vision impairment and the related worry, sadness and social exclusion. Common beliefs about the causes of vision impairment were environmental stressors (sun, dust, dirt and smoke), ageing and sorcery. Findings provide insight into the unique social context in PNG and identify a number of programmatic and policy implications, such as the need for preventative eye health information and services, addressing persisting beliefs in sorcery when developing health information packages, and the importance of coordinating with counselling and well-being services for people experiencing vision impairment.

Choriorétinite extensive bilatérale révélant une infection par le virus de l'immunodéficience humaine (VIH)

PubMed Central

El Yamouni, Oubaida; Tzili, Nazih; El Hassan, Abdallah; Slassi, Nadia; El Khaoua, Mahfoud; Jebbar, Zakaria; Berraho, Amina

2014-01-01

Au cours de l'infection par le virus de l'immunodéficience humaine(VIH), Les atteintes oculaires sont polymorphes, pouvant compromettre le pronostic fonctionnel. Nous rapportons l'observation d'un patient présentant une choriorétinite infectieuse sévère révélant une infection par le VIH. Patient âgé de 35 ans avec antécédent de tuberculose pulmonaire en 2007, consulte pour BAV bilatérale progressive depuis 6 mois. Une acuité visuelle à compte les doigts au niveau de l'oeil droit et à mouvement des doigts au niveau de l'oeil gauche, avec présence de foyers choriorétiniens diffus visualisés au fond d'oeil et à l'angiographie. Les sérologies VIH, toxoplasmose et CMV sont positives. Le patient a été mis sous traitement anti-toxoplasmose (Sulfadiazine et pyriméthamine) et anti-CMV (Ganciclovir per os). L’évolution sous traitement a été marquée par une régression de la hyalite avec la persistance des foyers choriorétiniens évolutifs et une acuité visuelle réduite à perception lumineuse. PMID:25709723

The Medawar Lecture 2001 Knowledge for vision: vision for knowledge

PubMed Central

Gregory, Richard L

2005-01-01

An evolutionary development of perception is suggested—from passive reception to active perception to explicit conception—earlier stages being largely retained and incorporated in later species. A key is innate and then individually learned knowledge, giving meaning to sensory signals. Inappropriate or misapplied knowledge produces rich cognitive phenomena of illusions, revealing normally hidden processes of vision, tentatively classified here in a ‘peeriodic table’. Phenomena of physiology are distinguished from phenomena of general rules and specific object knowledge. It is concluded that vision uses implicit knowledge, and provides knowledge for intelligent behaviour and for explicit conceptual understanding including science. PMID:16147519

Color vision in children and the Lanthony New Color Test.

PubMed

Ling, Barbara Y; Dain, Stephen J

2008-01-01

Much is known about color vision in infants, adolescents, and adults, but very few studies report the changes, which occur in color perception of children in their early schooling years. There is also a shortage of suitable color vision tests for children. This study investigated the changes in color vision of school students between 5-12 years old using the Lanthony New Color Test (NCT). Subjects of all ages were able to complete a shortened form of this test adequately. The Vingrys and King-Smith (1988) method of panel test analysis and Adams and Rodic (1982) color confusion score were adapted to analyze their performance of the test. This study confirmed that there are changes in color perception occurring in this age group. Color perception abilities increased as a function of age and there was also an improvement in the performance on the NCT with age. This can be attributed to both cognitive development and changes occurring to the color vision system.

Human factors involved in perception and action in a natural stereoscopic world: an up-to-date review with guidelines for stereoscopic displays and stereoscopic virtual reality (VR)

NASA Astrophysics Data System (ADS)

Perez-Bayas, Luis

2001-06-01

In stereoscopic perception of a three-dimensional world, binocular disparity might be thought of as the most important cue to 3D depth perception. Nevertheless, in reality there are many other factors involved before the 'final' conscious and subconscious stereoscopic perception, such as luminance, contrast, orientation, color, motion, and figure-ground extraction (pop-out phenomenon). In addition, more complex perceptual factors exist, such as attention and its duration (an equivalent of 'brain zooming') in relation to physiological central vision, In opposition to attention to peripheral vision and the brain 'top-down' information in relation to psychological factors like memory of previous experiences and present emotions. The brain's internal mapping of a pure perceptual world might be different from the internal mapping of a visual-motor space, which represents an 'action-directed perceptual world.' In addition, psychological factors (emotions and fine adjustments) are much more involved in a stereoscopic world than in a flat 2D-world, as well as in a world using peripheral vision (like VR, using a curved perspective representation, and displays, as natural vision does) as opposed to presenting only central vision (bi-macular stereoscopic vision) as in the majority of typical stereoscopic displays. Here is presented the most recent and precise information available about the psycho-neuro- physiological factors involved in the perception of stereoscopic three-dimensional world, with an attempt to give practical, functional, and pertinent guidelines for building more 'natural' stereoscopic displays.

Professional Vision: Elementary School Principals' Perceptions of Mathematics Instruction

ERIC Educational Resources Information Center

Schoen, Robert C.

2010-01-01

This study explored 78 elementary school principals' perceptions of classroom mathematics instruction in an effort to build understanding of the professional vision (Goodwin, 1994) of elementary school principals as it relates to mathematics instruction. This study also tested the theory of Leadership Content Knowledge (Stein & Nelson, 2003)…

Perceptions Matter: Administrators' Vision of Instruction for Students with Severe Disabilities

ERIC Educational Resources Information Center

Roberts, Carly A.; Ruppar, Andrea L.; Olson, Amy J.

2018-01-01

School administrators play an important role in shaping teaching and learning. However, very little is known regarding how school administrators perceive instruction for students with severe disabilities and how those perceptions shape expectations and visions for instruction. Semistructured interviews were used to interview 12 administrators…

Austerite et gestion dans les universites quebecoises: une analyse des perceptions de directeurs de departement=Austerity and Administration in Quebec's Universities: An Analysis of Department Heads' Perceptions.

ERIC Educational Resources Information Center

Crespo, Manuel; And Others

1986-01-01

A survey of 25 Quebec university department chairmen concerning the management of budgetary austerity found that administrative responses are generally perceived as reactionary and short-sighted, but long-term solutions proposed by chairmen are based on conflicting views of the overall role of the institution. (MSE)

Understanding Your Vision: The "Imperfect Eye"

MedlinePlus

... including peripheral awareness (side vision), eye coordination, depth perception, focusing ability, and color vision that make up ... the conditions for which you may be at risk." — Dr. Emily Chew National Eye Institute Farsighted If ...

Cortical visual dysfunction in children: a clinical study.

PubMed

Dutton, G; Ballantyne, J; Boyd, G; Bradnam, M; Day, R; McCulloch, D; Mackie, R; Phillips, S; Saunders, K

1996-01-01

Damage to the cerebral cortex was responsible for impairment in vision in 90 of 130 consecutive children referred to the Vision Assessment Clinic in Glasgow. Cortical blindness was seen in 16 children. Only 2 were mobile, but both showed evidence of navigational blind-sight. Cortical visual impairment, in which it was possible to estimate visual acuity but generalised severe brain damage precluded estimation of cognitive visual function, was observed in 9 children. Complex disorders of cognitive vision were seen in 20 children. These could be divided into five categories and involved impairment of: (1) recognition, (2) orientation, (3) depth perception, (4) perception of movement and (5) simultaneous perception. These disorders were observed in a variety of combinations. The remaining children showed evidence of reduced visual acuity and/ or visual field loss, but without detectable disorders of congnitive visual function. Early recognition of disorders of cognitive vision is required if active training and remediation are to be implemented.

Perception of the material properties of wood based on vision, audition, and touch.

PubMed

Fujisaki, Waka; Tokita, Midori; Kariya, Kenji

2015-04-01

Most research on the multimodal perception of material properties has investigated the perception of material properties of two modalities such as vision-touch, vision-audition, audition-touch, and vision-action. Here, we investigated whether the same affective classifications of materials can be found in three different modalities of vision, audition, and touch, using wood as the target object. Fifty participants took part in an experiment involving the three modalities of vision, audition, and touch, in isolation. Twenty-two different wood types including genuine, processed, and fake were perceptually evaluated using a questionnaire consisting of twenty-three items (12 perceptual and 11 affective). The results demonstrated that evaluations of the affective properties of wood were similar in all three modalities. The elements of "expensiveness, sturdiness, rareness, interestingness, and sophisticatedness" and "pleasantness, relaxed feelings, and liked-disliked" were separately grouped for all three senses. Our results suggest that the affective material properties of wood are at least partly represented in a supramodal fashion. Our results also suggest an association between perceptual and affective properties, which will be a useful tool not only in science, but also in applied fields. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

A discrepancy within primate spatial vision and its bearing on the definition of edge detection processes in machine vision

NASA Technical Reports Server (NTRS)

Jobson, Daniel J.

1990-01-01

The visual perception of form information is considered to be based on the functioning of simple and complex neurons in the primate striate cortex. However, a review of the physiological data on these brain cells cannot be harmonized with either the perceptual spatial frequency performance of primates or the performance which is necessary for form perception in humans. This discrepancy together with recent interest in cortical-like and perceptual-like processing in image coding and machine vision prompted a series of image processing experiments intended to provide some definition of the selection of image operators. The experiments were aimed at determining operators which could be used to detect edges in a computational manner consistent with the visual perception of structure in images. Fundamental issues were the selection of size (peak spatial frequency) and circular versus oriented operators (or some combination). In a previous study, circular difference-of-Gaussian (DOG) operators, with peak spatial frequency responses at about 11 and 33 cyc/deg were found to capture the primary structural information in images. Here larger scale circular DOG operators were explored and led to severe loss of image structure and introduced spatial dislocations (due to blur) in structure which is not consistent with visual perception. Orientation sensitive operators (akin to one class of simple cortical neurons) introduced ambiguities of edge extent regardless of the scale of the operator. For machine vision schemes which are functionally similar to natural vision form perception, two circularly symmetric very high spatial frequency channels appear to be necessary and sufficient for a wide range of natural images. Such a machine vision scheme is most similar to the physiological performance of the primate lateral geniculate nucleus rather than the striate cortex.

Sensorimotor Interactions in the Haptic Perception of Virtual Objects

DTIC Science & Technology

1997-01-01

the human user. 2 Compared to our understanding of vision and audition , our knowledge of the human haptic perception is very limited. Many basic...modalities such as vision and audition on haptic perception of viscosity or mass, for example. 116 Some preliminary work has already been done in this...string[3]; *posx="x" *forf="f’ *velv="v" * acca ="a" trial[64]; resp[64]; /* random number */ /* trial number */ /* index */ /* array holding stim

Aptitude visuelle à la conduite automobile: exemple des candidats au permis de conduire à Libreville

PubMed Central

Souhail, Hassane; Assoumou, Prudence; Birinda, Hilda; Mengome, Emmanuel Mve

2015-01-01

L'objectif était d’évaluer l'aptitude visuelle à la conduite automobile des candidats au permis de conduire à Libreville. Il s'agissait d'une étude transversale, descriptive et analytique, qui s'est déroulée à Libreville pendant la période du 4 avril 2012 au 14 juillet 2012 (soit 4 mois et 10 jours). La population d’étude concernait les candidats soumis aux épreuves d'obtention du permis de conduire. Nous avons inclus dans notre travail, les candidats, ayant donné leur consentement par écrit et exclus ceux refusant d'adhérer à l'enquête. Les variables étudiées concernaient l’âge, le sexe, la population d’étude, l'activité professionnelle, l'acuité visuelle de loin et de près, la vision des couleurs, la catégorie du permis de conduire, et l'aptitude visuelle à la conduite automobile. La saisie et l'analyse des données ont été collectées au moyen d'une fiche d'enquête standardisée; après vérification et validation, elles ont été saisies sur le logiciel Excel Windows et analysées sur le logiciel Epi Info version 3.5.1. L’âge moyen des 406 candidats était de 29 ans ± 6,65 ans avec des extrêmes allant de 17 ans à 52 ans. Les hommes représentaient 283 (69,7%) et les femmes 123 (30,3%), soit un ratio de 2,3. Les fonctionnaires étaient retrouvés dans 39,4 % des cas, suivi des élèves-étudiants dans 33,5%. Dans notre population d’étude, 71 sur 406 candidats avaient une baisse de l'acuité visuelle de loin, soit 17,5%. Dans notre série, nous avons retrouvés 34 candidats âgés de 40 ans et plus, et seulement 14 candidats (41,2%) avaient une baisse de l'acuité visuelle de près. La quasi-totalité des patients avaient une vision de couleurs normale (99,5%), cependant 2 candidats avaient une vision de couleurs anormale, soit une prévalence de 0,5%. Dans notre échantillon, 403 (99,3%) sollicitaient un permis de conduire de catégorie léger (perms A, A1, B, F) et 3 (0,7%) sollicitaient un permis de conduire de type lourd ( C,D,E). Les candidats pour la catégorie de permis légers étaient inaptes dans 10 cas soit 2,5% de la population d’étude. Toutefois, tous les candidats à la catégorie de permis lourd étaient aptes à la conduite automobile. Nos résultats montraient que 2,5% des candidats étaient inaptes à la conduite automobile et que l'examen ophtalmologique n'avait pas été réalisé pour la quasi- totalité des candidats dans le cadre de l'obtention du permis de conduire. Rappelons toutefois que, l’évaluation de l'aptitude visuelle du futur conducteur constitue un acte de prévention de sécurité routière et qu'il revient donc à l'ophtalmologiste de délivrer le certificat d'aptitude visuelle à la conduite, pour s'assurer que le candidat au permis de conduire ne présente pas d'affection visuelle incompatible avec la conduite automobile. PMID:26889328

Cognitive penetration of early vision in face perception.

PubMed

Cecchi, Ariel S

2018-06-13

Cognitive and affective penetration of perception refers to the influence that higher mental states such as beliefs and emotions have on perceptual systems. Psychological and neuroscientific studies appear to show that these states modulate the visual system at the visuomotor, attentional, and late levels of processing. However, empirical evidence showing that similar consequences occur in early stages of visual processing seems to be scarce. In this paper, I argue that psychological evidence does not seem to be either sufficient or necessary to argue in favour of or against the cognitive penetration of perception in either late or early vision. In order to do that we need to have recourse to brain imaging techniques. Thus, I introduce a neuroscientific study and argue that it seems to provide well-grounded evidence for the cognitive penetration of early vision in face perception. I also examine and reject alternative explanations to my conclusion. Copyright © 2018 Elsevier Inc. All rights reserved.

Grasping the Muller-Lyer Illusion: The Contributions of Vision for Perception in Action

ERIC Educational Resources Information Center

van Doorn, Hemke; van der Kamp, John; Savelsbergh, Geert J. P.

2007-01-01

The present study examines the contributions of vision for perception processes in action. To this end, the influence of allocentric information on different action components (i.e., the selection of an appropriate mode of action, the pre-planning and online control of movement kinematics) is assessed. Participants (n = 10) were presented with a…

Molecular patterns of X chromosome-linked color vision genes among 134 men of European ancestry.

PubMed Central

Drummond-Borg, M; Deeb, S S; Motulsky, A G

1989-01-01

We used Southern blot hybridization to study X chromosome-linked color vision genes encoding the apoproteins of red and green visual pigments in 134 unselected Caucasian men. One hundred and thirteen individuals (84.3%) had a normal arrangement of their color vision pigment genes. All had one red pigment gene; the number of green pigment genes ranged from one to five with a mode of two. The frequency of molecular genotypes indicative of normal color vision (84.3%) was significantly lower than had been observed in previous studies of color vision phenotypes. Color vision defects can be due to deletions of red or green pigment genes or due to formation of hybrid genes comprising portions of both red and green pigment genes [Nathans, J., Piantanida, T.P., Eddy, R.L., Shows, T.B., Jr., & Hogness, D.S. (1986) Science 232, 203-210]. Characteristic anomalous patterns were seen in 15 (11.2%) individuals: 7 (5.2%) had patterns characteristic of deuteranomaly (mild defect in green color perception), 2 (1.5%) had patterns characteristic of deuteranopia (severe defect in green color perception), and 6 (4.5%) had protan patterns (the red perception defects protanomaly and protanopia cannot be differentiated by current molecular methods). Previously undescribed hybrid gene patterns consisting of both green and red pigment gene fragments in addition to normal red and green genes were observed in another 6 individuals (4.5%). Only 2 of these patterns were considered as deuteranomalous. Thus, DNA testing detected anomalous color vision pigment genes at a higher frequency than expected from phenotypic color vision tests. Some color vision gene arrays associated with hybrid genes are likely to mediate normal color vision. Images PMID:2915991

Rationality, perception, and the all-seeing eye.

PubMed

Felin, Teppo; Koenderink, Jan; Krueger, Joachim I

2017-08-01

Seeing-perception and vision-is implicitly the fundamental building block of the literature on rationality and cognition. Herbert Simon and Daniel Kahneman's arguments against the omniscience of economic agents-and the concept of bounded rationality-depend critically on a particular view of the nature of perception and vision. We propose that this framework of rationality merely replaces economic omniscience with perceptual omniscience. We show how the cognitive and social sciences feature a pervasive but problematic meta-assumption that is characterized by an "all-seeing eye." We raise concerns about this assumption and discuss different ways in which the all-seeing eye manifests itself in existing research on (bounded) rationality. We first consider the centrality of vision and perception in Simon's pioneering work. We then point to Kahneman's work-particularly his article "Maps of Bounded Rationality"-to illustrate the pervasiveness of an all-seeing view of perception, as manifested in the extensive use of visual examples and illusions. Similar assumptions about perception can be found across a large literature in the cognitive sciences. The central problem is the present emphasis on inverse optics-the objective nature of objects and environments, e.g., size, contrast, and color. This framework ignores the nature of the organism and perceiver. We argue instead that reality is constructed and expressed, and we discuss the species-specificity of perception, as well as perception as a user interface. We draw on vision science as well as the arts to develop an alternative understanding of rationality in the cognitive and social sciences. We conclude with a discussion of the implications of our arguments for the rationality and decision-making literature in cognitive psychology and behavioral economics, along with suggesting some ways forward.

The Impact of Vision in Spatial Coding

ERIC Educational Resources Information Center

Papadopoulos, Konstantinos; Koustriava, Eleni

2011-01-01

The aim of this study is to examine the performance in coding and representing of near-space in relation to vision status (blindness vs. normal vision) and sensory modality (touch vs. vision). Forty-eight children and teenagers participated. Sixteen of the participants were totally blind or had only light perception, 16 were blindfolded sighted…

What Aspects of Vision Facilitate Haptic Processing?

ERIC Educational Resources Information Center

Millar, Susanna; Al-Attar, Zainab

2005-01-01

We investigate how vision affects haptic performance when task-relevant visual cues are reduced or excluded. The task was to remember the spatial location of six landmarks that were explored by touch in a tactile map. Here, we use specially designed spectacles that simulate residual peripheral vision, tunnel vision, diffuse light perception, and…

Seeing the body distorts tactile size perception.

PubMed

Longo, Matthew R; Sadibolova, Renata

2013-03-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception. Copyright © 2012 Elsevier B.V. All rights reserved.

Color universal design: analysis of color category dependency on color vision type (3)

NASA Astrophysics Data System (ADS)

Kojima, Natsuki; Ichihara, Yasuyo G.; Ikeda, Tomohiro; Kamachi, Miyuki G.; Ito, Kei

2012-01-01

We report on the results of a study investigating the color perception characteristics of people with red-green color confusion. We believe that this is an important step towards achieving Color Universal Design. In Japan, approximately 5% of men and 0.2% of women have red-green confusion. The percentage for men is higher in Europe and the United States; up to 8% in some countries. Red-green confusion involves a perception of colors different from normal color vision. Colors are used as a means of disseminating clear information to people; however, it may be difficult to convey the correct information to people who have red-green confusion. Consequently, colors should be chosen that minimize accidents and that promote more effective communication. In a previous survey, we investigated color categories common to each color vision type, trichromat (C-type color vision), protan (P-type color vision) and deuteran (D-type color vision). In the present study, first, we conducted experiments in order to verify a previous survey of C-type color vision and P-type color vision. Next, we investigated color difference levels within "CIE 1976 L*a*b*" (the CIELAB uniform color space), where neither C-type nor P-type color vision causes accidents under certain conditions (rain maps/contour line levels and graph color legend levels). As a result, we propose a common chromaticity of colors that the two color vision types are able to categorize by means of color names common to C-type color vision. We also offer a proposal to explain perception characteristics of color differences with normal color vision and red-green confusion using the CIELAB uniform color space. This report is a follow-up to SPIE-IS & T / Vol. 7528 7528051-8 and SPIE-IS & T /vol. 7866 78660J-1-8.

Both vision-for-perception and vision-for-action follow Weber's law at small object sizes, but violate it at larger sizes.

PubMed

Bruno, Nicola; Uccelli, Stefano; Viviani, Eva; de'Sperati, Claudio

2016-10-01

According to a previous report, the visual coding of size does not obey Weber's law when aimed at guiding a grasp (Ganel et al., 2008a). This result has been interpreted as evidence for a fundamental difference between sensory processing in vision-for-perception, which needs to compress a wide range of physical objects to a restricted range of percepts, and vision-for-action when applied to the much narrower range of graspable and reachable objects. We compared finger aperture in a motor task (precision grip) and perceptual task (cross modal matching or "manual estimation" of the object's size). Crucially, we tested the whole range of graspable objects. We report that both grips and estimations clearly violate Weber's law with medium-to-large objects, but are essentially consistent with Weber's law with smaller objects. These results differ from previous characterizations of perception-action dissociations in the precision of representations of object size. Implications for current functional interpretations of the dorsal and ventral processing streams in the human visual system are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modulation frequency as a cue for auditory speed perception.

PubMed

Senna, Irene; Parise, Cesare V; Ernst, Marc O

2017-07-12

Unlike vision, the mechanisms underlying auditory motion perception are poorly understood. Here we describe an auditory motion illusion revealing a novel cue to auditory speed perception: the temporal frequency of amplitude modulation (AM-frequency), typical for rattling sounds. Naturally, corrugated objects sliding across each other generate rattling sounds whose AM-frequency tends to directly correlate with speed. We found that AM-frequency modulates auditory speed perception in a highly systematic fashion: moving sounds with higher AM-frequency are perceived as moving faster than sounds with lower AM-frequency. Even more interestingly, sounds with higher AM-frequency also induce stronger motion aftereffects. This reveals the existence of specialized neural mechanisms for auditory motion perception, which are sensitive to AM-frequency. Thus, in spatial hearing, the brain successfully capitalizes on the AM-frequency of rattling sounds to estimate the speed of moving objects. This tightly parallels previous findings in motion vision, where spatio-temporal frequency of moving displays systematically affects both speed perception and the magnitude of the motion aftereffects. Such an analogy with vision suggests that motion detection may rely on canonical computations, with similar neural mechanisms shared across the different modalities. © 2017 The Author(s).

Vision/Visual Perception: An Annotated Bibliography.

ERIC Educational Resources Information Center

Weintraub, Sam, Comp.; Cowan, Robert J., Comp.

An update and modification of "Vision-Visual Discrimination" published in 1973, this annotated bibliography contains entries from the annual summaries of research in reading published by the International Reading Association (IRA) since then. The first large section, "Vision," is divided into two subgroups: (1) "Visually…

Topographic Mapping of Residual Vision by Computer

ERIC Educational Resources Information Center

MacKeben, Manfred

2008-01-01

Many persons with low vision have diseases that damage the retina only in selected areas, which can lead to scotomas (blind spots) in perception. The most frequent of these diseases is age-related macular degeneration (AMD), in which foveal vision is often impaired by a central scotoma that impairs vision of fine detail and causes problems with…

Colour vision experimental studies in teaching of optometry

NASA Astrophysics Data System (ADS)

Ozolinsh, Maris; Ikaunieks, Gatis; Fomins, Sergejs

2005-10-01

Following aspects related to human colour vision are included in experimental lessons for optometry students of University of Latvia. Characteristics of coloured stimuli (emitting and reflective), determination their coordinates in different colour spaces. Objective characteristics of transmitting of colour stimuli through the optical system of eye together with various types of appliances (lenses, prisms, Fresnel prisms). Psychophysical determination of mono- and polychromatic stimuli perception taking into account physiology of eye, retinal colour photoreceptor topography and spectral sensitivity, spatial and temporal characteristics of retinal receptive fields. Ergonomics of visual perception, influence of illumination and glare effects, testing of colour vision deficiencies.

An Emphasis on Perception: Teaching Image Formation Using a Mechanistic Model of Vision.

ERIC Educational Resources Information Center

Allen, Sue; And Others

An effective way to teach the concept of image is to give students a model of human vision which incorporates a simple mechanism of depth perception. In this study two almost identical versions of a curriculum in geometrical optics were created. One used a mechanistic, interpretive eye model, and in the other the eye was modeled as a passive,…

The Influence of Modern Adolescents' Vision of Life on Their Perception of Art

ERIC Educational Resources Information Center

Torshilova, Elena M.; Polosukhina, Irina A.

2016-01-01

During The aim of the multi-year study, conducted by the authors of present article, is to reveal the characteristics of social-cultural portrait of 9-16-year-old children, who grow up in the XXI century, along with the influence of modern children's vision of life on their perception of art. In order to solve the problem, the authors used the…

Understanding Dali's Slave market with the disappearing bust of Voltaire: a case study in the scale information driving perception.

PubMed

Bonnar, Lizann; Gosselin, Frédéric; Schyns, Philippe G

2002-01-01

A generic problem in vision is to know which information drives the perception of a stimulus. We address this problem in a case study that involves the perceptual reversal of an ambiguous image (here, Dali's painting the Slave Market with the Disappearing Bust of Voltaire 1940). In experiment 1, we use 'bubbles' (Gosselin and Schyns, 2001 Vision Research 41 2261-2271) to disambiguate the image and to determine the specific visual information that drives each possible perception (here, the nuns versus the bust of Voltaire). Experiment 2 validates that this information does determine the selective perception of the ambiguous image. We adapted the spatial-frequency channels of observers selectively to the information that mediates one of the two perceptions, to induce the opposite perception of the ambiguous image in a transfer phase. Together, the results suggest a method of revealing the visual information that drives perception.

Conséquences comportementales de la violence faite aux enfants

PubMed Central

Al Odhayani, Abdulaziz; Watson, William J.; Watson, Lindsay

2013-01-01

Résumé Objectif Discuter des répercussions de la violence sur le développement comportemental durant l’enfance, mettre en évidence certains signes comportementaux susceptibles d’alerter les médecins à la présence d’une maltraitance continue d’un enfant et explorer le rôle précis du médecin de famille dans une telle situation clinique. Sources des données Une recension systématique a servi à examiner la recherche pertinente, les articles de révision clinique et les sites web des organismes de protection de la jeunesse. Message principal Le comportement d’un enfant est une manifestation extériorisée de sa stabilité et de sa sécurité intérieures. C’est une lentille au travers de laquelle le médecin de famille peut observer le développement de l’enfant pendant toute sa vie. Tous les genres de violence sont dommageables pour les enfants, qu’elle soit physique, affective ou psychologique, et peuvent causer des problèmes à long terme dans le développement du comportement et de la santé mentale. Les médecins de famille doivent connaître les indices de maltraitance et de négligence envers les enfants et être aux aguets de ces derniers afin d’entreprendre les interventions appropriées et améliorer les résultats pour ces enfants. Conclusion La violence faite aux enfants peut causer un développement psychologique désordonné et des problèmes de comportement. Les médecins de famille exercent un rôle important dans la reconnaissance des signes comportementaux laissant présager une maltraitance, ainsi que pour offrir de l’aide afin de protéger les enfants.

Neuro-ophthalmic manifestations of cerebrovascular accidents.

PubMed

Ghannam, Alaa S Bou; Subramanian, Prem S

2017-11-01

Ocular functions can be affected in almost any type of cerebrovascular accident (CVA) creating a burden on the patient and family and limiting functionality. The present review summarizes the different ocular outcomes after stroke, divided into three categories: vision, ocular motility, and visual perception. We also discuss interventions that have been proposed to help restore vision and perception after CVA. Interventions that might help expand or compensate for visual field loss and visuospatial neglect include explorative saccade training, prisms, visual restoration therapy (VRT), and transcranial direct current stimulation (tDCS). VRT makes use of neuroplasticity, which has shown efficacy in animal models but remains controversial in human studies. CVAs can lead to decreased visual acuity, visual field loss, ocular motility abnormalities, and visuospatial perception deficits. Although ocular motility problems can be corrected with surgery, vision, and perception deficits are more difficult to overcome. Interventions to restore or compensate for visual field deficits are controversial despite theoretical underpinnings, animal model evidence, and case reports of their efficacies.

Vision

NASA Technical Reports Server (NTRS)

Taylor, J. H.

1973-01-01

Some data on human vision, important in present and projected space activities, are presented. Visual environment and performance and structure of the visual system are also considered. Visual perception during stress is included.

Spatiotemporal Processing in Crossmodal Interactions for Perception of the External World: A Review

PubMed Central

Hidaka, Souta; Teramoto, Wataru; Sugita, Yoichi

2015-01-01

Research regarding crossmodal interactions has garnered much interest in the last few decades. A variety of studies have demonstrated that multisensory information (vision, audition, tactile sensation, and so on) can perceptually interact with each other in the spatial and temporal domains. Findings regarding crossmodal interactions in the spatiotemporal domain (i.e., motion processing) have also been reported, with updates in the last few years. In this review, we summarize past and recent findings on spatiotemporal processing in crossmodal interactions regarding perception of the external world. A traditional view regarding crossmodal interactions holds that vision is superior to audition in spatial processing, but audition is dominant over vision in temporal processing. Similarly, vision is considered to have dominant effects over the other sensory modalities (i.e., visual capture) in spatiotemporal processing. However, recent findings demonstrate that sound could have a driving effect on visual motion perception. Moreover, studies regarding perceptual associative learning reported that, after association is established between a sound sequence without spatial information and visual motion information, the sound sequence could trigger visual motion perception. Other sensory information, such as motor action or smell, has also exhibited similar driving effects on visual motion perception. Additionally, recent brain imaging studies demonstrate that similar activation patterns could be observed in several brain areas, including the motion processing areas, between spatiotemporal information from different sensory modalities. Based on these findings, we suggest that multimodal information could mutually interact in spatiotemporal processing in the percept of the external world and that common perceptual and neural underlying mechanisms would exist for spatiotemporal processing. PMID:26733827

Seeing the Body Distorts Tactile Size Perception

ERIC Educational Resources Information Center

Longo, Matthew R.; Sadibolova, Renata

2013-01-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of…

Réparation juridique en dommage corporel de l’insuffisance antéhypophysaire post-traumatique

PubMed Central

Mahjoub, Mohamed; Jedidi, Maher; Mezgar, Zied; Masmoudi, Tasnim; Zhioua, Mongi; Euch, Koussay El; Njah, Mansour

2017-01-01

L'insuffisance antéhypophysaire post-traumatique (IAHPT) est une pathologie exceptionnelle mais de réalité certaine résultant des lésions ischémiques lors des traumatismes crâniens (TC) sévères. L'objectif est de préciser à partir d'une étude de cas les critères d'imputabilité de l'IAHPT suite au (TC) ainsi que les spécificités relatifs à sa réparation juridique. C'est une étude médico-légale d'un cas d'IAHPT, diagnostiqué et suivi au service d'endocrinologie et de médecine légale du CHU de Sousse (Tunisie). Il s'agit d'une femme âgée de 45 ans, sans antécédents pathologiques (6 gestes, 4 parités et 2 avortements) ayant un cycle menstruel régulier, sans notion d'accouchement hémorragique, qui a été victime d'un accident de la voie publique (piétonne, heurtée puis renversée par une voiture) occasionnant un TC avec point d'impact occipital sans perte de connaissance initiale; ayant présenté trois ans après l'accident, une hypothyroïdie. L'exploration hormonale rapporte l'atteinte de tous les autres axes. L'exploration neuroradiologique retrouve une intégrité de l'hypophyse et de la tige. Le diagnostic définitif est l'IAHPT. L'expertise médicale (faite 4 ans après l'accident) a conclue à l'imputabilité de l'IAHPT à l'accident. Le taux d'incapacité partielle permanente IIP en droit commun a été évalué à 25%. L'IAHPT est un diagnostic d'élimination. L'évaluation du dommage corporel doit tenir compte des symptômes résiduels, contraintes thérapeutiques et répercussions sur l'activité quotidienne et professionnelle. L'évolution sous hormonothérapie de substitution est souvent favorable, cependant, elle peut être émaillée de complications, d'où l'obligation d'établir des réserves préservant ainsi le droit du patient à une nouvelle révision.

Effects of Self-Esteem and Mortality Salience on Attitudes Toward Canadian Security: Exploring the Significance of Implicit-Explicit and Personal-Collective Distinctions (Les Effets de L’Estime de soi et de la Pregnance de la Mort sur les Attitudes a L’Egard de la Securite Canadienne: Analyse de L’Importance des Distinctions entre Implicite et Explicite d’une Part et entre Personnel et Collectif D’Autre Part)

DTIC Science & Technology

2011-04-01

la Reine (en droit du Canada), telle que représentée par le ministre de la Défense nationale, 2011 DRDC Toronto TR... la gestion de la terreur, c’est parce que les êtres humains sont les seuls à posséder la capacité de comprendre la finitude de la vie qu’ils ont...entre autres l’adhésion à une vision du monde culturellement significative et un sentiment de sécurité basé sur l’estime de soi. À ce jour,

Application de l’analyse des séries chronologiques à la projection d’effectifs de population scolaire par la méthode des composantes

PubMed Central

Smith, Herbert L.

2016-01-01

Cet article veut montrer qu’on peut réécrire des modèles démographiques en vue de réaliser des projections par cohorte, en les transposant dans un modèle économétrique vecteur autoré-gressif (VAR). De cette façon, la méthode des composantes se dote d’un cadre stochastique qui étend son envergure. Le potentiel de cette perspective est illustré à travers l’exemple d’une projection d’effectifs de population scolaire. Il met en valeur une série d’équations qui permet de vérifier la validité de plusieurs choix de modélisations habituellement utilisées dans le domaine de la prévision. PMID:27346921

Forming Effective Partnerships to Facilitate Inclusion of Students with Vision Impairments: Perceptions of a Regular Classroom Teacher and an Itinerant Teacher

ERIC Educational Resources Information Center

Sharma, Umesh; Moore, Dennis; Furlonger, Brett; King, Brian Smyth; Kaye, Linda; Constantinou, Olga

2010-01-01

This qualitative study reports on the perceptions of a regular classroom teacher and an itinerant teacher about the challenges they faced in including a student with vision impairment in regular school in New South Wales, Australia. Some of the common strategies employed by both these teachers to address these challenges are discussed. (Contains 1…

Symbolic Model of Perception in Dynamic 3D Environments

DTIC Science & Technology

2006-11-01

can retrieve memories , work on goals, recognize visual or aural percepts, and perform actions. ACT-R has been selected for the current...types of memory . Procedural memory is the store of condition- action productions that are selected and executed by the core production system...a declarative memory chunk that is made available to the core production system through the vision module . 4 The vision module has been

Neck and shoulder muscle activity and posture among helicopter pilots and crew-members during military helicopter flight.

PubMed

Murray, Mike; Lange, Britt; Chreiteh, Shadi Samir; Olsen, Henrik Baare; Nørnberg, Bo Riebeling; Boyle, Eleanor; Søgaard, Karen; Sjøgaard, Gisela

2016-04-01

Neck pain among helicopter pilots and crew-members is common. This study quantified the physical workload on neck and shoulder muscles using electromyography (EMG) measures during helicopter flight. Nine standardized sorties were performed, encompassing: cruising from location A to location B (AB) and performing search and rescue (SAR). SAR was performed with Night Vision Goggles (NVG), while AB was performed with (AB+NVG) and without NVG (AB-NVG). EMG was recorded for: trapezius (TRA), upper neck extensors (UNE), and sternocleido-mastoid (SCM). Maximal voluntary contractions (MVC) were performed for normalization of EMG (MVE). Neck posture of pilots and crew-members was monitored and pain intensity of neck, shoulder, and back was recorded. Mean muscle activity for UNE was ∼10% MVE and significantly higher than TRA and SCM, and SCM was significantly lower than TRA. There was no significant difference between AB-NVG and AB+NVG. Muscle activity in the UNE was significantly higher during SAR+NVG than AB-NVG. Sortie time (%) with non-neutral neck posture for SAR+NVG and AB-NVG was: 80.4%, 74.5% (flexed), 55.5%, 47.9% (rotated), 4.5%, 3.7% (lateral flexed). Neck pain intensity increased significantly from pre- (0.7±1.3) to post-sortie (1.6±1.9) for pilots (p=0.028). If sustained, UNE activity of ∼10% MVE is high, and implies a risk for neck disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of adherence to ambulatory liquid oxygen treatment: are commercialized dual-pressure transducers helpful?

PubMed

van Zeller, Mafalda; Eusébio, Ermelinda; Almeida, João; Winck, João Carlos

2014-09-01

Treatment adherence is widely recognized as a critical problem in long-term oxygen therapy, particularly in ambulatory liquid oxygen (LOX) systems. Adherence-monitoring strategies may be helpful in managing patients. We evaluated subjects' adherence to LOX using VisionOx and compared these results with the subjects' own adherence diaries and self-reported perceptions of use. Patients using LOX were recruited for a clinical interview; the number of days/week and the mean time of use according to subjects' perceptions were recorded. A 14-day diary was provided for every subject while VisionOx was attached to the LOX. VisionOx is a small device that uses pressure transducers to detect oxygen flow and the subject's breathing frequency. Information is stored and downloaded using dedicated software. Nineteen subjects were included (57.9% male with a median age of 63 years). When asked about the perception of LOX use, subjects self-reported using the device for a median of 100.0% of days (78.9% reported to have used it every day) for a median time of 180 min/day. According to data from VisionOx and subjects' diaries during the 14-day evaluation period, the median use was 92.8% of days for 210 min/day. No difference was found between the diaries and VisionOx data. Regarding subjects' perceptions of use, the declared use of LOX percent was significantly higher than reported in the diaries (P = .045) and VisionOx monitoring (P = .045) even though both underestimated the median use per day. Subjects overestimated adherence to LOX therapy (when measuring percent of days of use) compared to adherence diary and objective adherence monitoring. Because no significant difference was found comparing the diaries and VisionOx use, either may be helpful in clinical practice. Copyright © 2014 by Daedalus Enterprises.

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

PubMed

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.

Integration des Enfants en Difficulte: Resultats d'une Enquete Portant sur les Opinions et Perceptions des Etudiantes et Etudiants a la Formation du Personnel Enseignant (Integration of At-Risk Children: Results of an Inquiry on the Opinions and Perceptions of Preservice Teachers).

ERIC Educational Resources Information Center

Gauthier, Yvon

1996-01-01

This article reports the results of a survey of 150 Ontario (Canada) university students who were education majors. The survey investigated their attitudes towards the inclusion of children with disabilities into general education classes. The respondents had favorable attitudes toward inclusion but did not perceive themselves as being…

Student Perceptions and Lessons Learned from Flipping a Master's Level Environmental and Occupational Health Course (Perceptions des étudiants et leçons tirées d'une classe inversée pour un cours de maîtrise en santé environnementale et professionnelle)

ERIC Educational Resources Information Center

Galway, Lindsay P.; Berry, Barbara; Takaro, Timothy K.

2015-01-01

The flipped classroom instructional model has emerged as an alternative to the conventional lecture-based teaching that has dominated higher education for decades. In 2013, a cohort of graduate-level public health students participated in a flipped environmental and occupational health course. We present the design, implementation, and evaluation…

Sensory Drive, Color, and Color Vision.

PubMed

Price, Trevor D

2017-08-01

Colors often appear to differ in arbitrary ways among related species. However, a fraction of color diversity may be explained because some signals are more easily perceived in one environment rather than another. Models show that not only signals but also the perception of signals should regularly evolve in response to different environments, whether these primarily involve detection of conspecifics or detection of predators and prey. Thus, a deeper understanding of how perception of color correlates with environmental attributes should help generate more predictive models of color divergence. Here, I briefly review our understanding of color vision in vertebrates. Then I focus on opsin spectral tuning and opsin expression, two traits involved in color perception that have become amenable to study. I ask how opsin tuning is correlated with ecological differences, notably the light environment, and how this potentially affects perception of conspecific colors. Although opsin tuning appears to evolve slowly, opsin expression levels are more evolutionarily labile but have been difficult to connect to color perception. The challenge going forward will be to identify how physiological differences involved in color vision, such as opsin expression levels, translate into perceptual differences, the selection pressures that have driven those differences, and ultimately how this may drive evolution of conspecific colors.

Examining age-related shared variance between face cognition, vision, and self-reported physical health: a test of the common cause hypothesis for social cognition

PubMed Central

Olderbak, Sally; Hildebrandt, Andrea; Wilhelm, Oliver

2015-01-01

The shared decline in cognitive abilities, sensory functions (e.g., vision and hearing), and physical health with increasing age is well documented with some research attributing this shared age-related decline to a single common cause (e.g., aging brain). We evaluate the extent to which the common cause hypothesis predicts associations between vision and physical health with social cognition abilities specifically face perception and face memory. Based on a sample of 443 adults (17–88 years old), we test a series of structural equation models, including Multiple Indicator Multiple Cause (MIMIC) models, and estimate the extent to which vision and self-reported physical health are related to face perception and face memory through a common factor, before and after controlling for their fluid cognitive component and the linear effects of age. Results suggest significant shared variance amongst these constructs, with a common factor explaining some, but not all, of the shared age-related variance. Also, we found that the relations of face perception, but not face memory, with vision and physical health could be completely explained by fluid cognition. Overall, results suggest that a single common cause explains most, but not all age-related shared variance with domain specific aging mechanisms evident. PMID:26321998

Cross-Modal Correspondence Among Vision, Audition, and Touch in Natural Objects: An Investigation of the Perceptual Properties of Wood.

PubMed

Kanaya, Shoko; Kariya, Kenji; Fujisaki, Waka

2016-10-01

Certain systematic relationships are often assumed between information conveyed from multiple sensory modalities; for instance, a small figure and a high pitch may be perceived as more harmonious. This phenomenon, termed cross-modal correspondence, may result from correlations between multi-sensory signals learned in daily experience of the natural environment. If so, we would observe cross-modal correspondences not only in the perception of artificial stimuli but also in perception of natural objects. To test this hypothesis, we reanalyzed data collected previously in our laboratory examining perceptions of the material properties of wood using vision, audition, and touch. We compared participant evaluations of three perceptual properties (surface brightness, sharpness of sound, and smoothness) of the wood blocks obtained separately via vision, audition, and touch. Significant positive correlations were identified for all properties in the audition-touch comparison, and for two of the three properties regarding in the vision-touch comparison. By contrast, no properties exhibited significant positive correlations in the vision-audition comparison. These results suggest that we learn correlations between multi-sensory signals through experience; however, the strength of this statistical learning is apparently dependent on the particular combination of sensory modalities involved. © The Author(s) 2016.

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

NASA Technical Reports Server (NTRS)

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.

Conscious Vision Proceeds from Global to Local Content in Goal-Directed Tasks and Spontaneous Vision.

PubMed

Campana, Florence; Rebollo, Ignacio; Urai, Anne; Wyart, Valentin; Tallon-Baudry, Catherine

2016-05-11

The reverse hierarchy theory (Hochstein and Ahissar, 2002) makes strong, but so far untested, predictions on conscious vision. In this theory, local details encoded in lower-order visual areas are unconsciously processed before being automatically and rapidly combined into global information in higher-order visual areas, where conscious percepts emerge. Contingent on current goals, local details can afterward be consciously retrieved. This model therefore predicts that (1) global information is perceived faster than local details, (2) global information is computed regardless of task demands during early visual processing, and (3) spontaneous vision is dominated by global percepts. We designed novel textured stimuli that are, as opposed to the classic Navon's letters, truly hierarchical (i.e., where global information is solely defined by local information but where local and global orientations can still be manipulated separately). In line with the predictions, observers were systematically faster reporting global than local properties of those stimuli. Second, global information could be decoded from magneto-encephalographic data during early visual processing regardless of task demands. Last, spontaneous subjective reports were dominated by global information and the frequency and speed of spontaneous global perception correlated with the accuracy and speed in the global task. No such correlation was observed for local information. We therefore show that information at different levels of the visual hierarchy is not equally likely to become conscious; rather, conscious percepts emerge preferentially at a global level. We further show that spontaneous reports can be reliable and are tightly linked to objective performance at the global level. Is information encoded at different levels of the visual system (local details in low-level areas vs global shapes in high-level areas) equally likely to become conscious? We designed new hierarchical stimuli and provide the first empirical evidence based on behavioral and MEG data that global information encoded at high levels of the visual hierarchy dominates perception. This result held both in the presence and in the absence of task demands. The preferential emergence of percepts at high levels can account for two properties of conscious vision, namely, the dominance of global percepts and the feeling of visual richness reported independently of the perception of local details. Copyright © 2016 the authors 0270-6474/16/365200-14$15.00/0.

Visual enhancing of tactile perception in the posterior parietal cortex.

PubMed

Ro, Tony; Wallace, Ruth; Hagedorn, Judith; Farnè, Alessandro; Pienkos, Elizabeth

2004-01-01

The visual modality typically dominates over our other senses. Here we show that after inducing an extreme conflict in the left hand between vision of touch (present) and the feeling of touch (absent), sensitivity to touch increases for several minutes after the conflict. Transcranial magnetic stimulation of the posterior parietal cortex after this conflict not only eliminated the enduring visual enhancement of touch, but also impaired normal tactile perception. This latter finding demonstrates a direct role of the parietal lobe in modulating tactile perception as a result of the conflict between these senses. These results provide evidence for visual-to-tactile perceptual modulation and demonstrate effects of illusory vision of touch on touch perception through a long-lasting modulatory process in the posterior parietal cortex.

Pre-Service Teacher Vision and Urban Schools

ERIC Educational Resources Information Center

Roselle, Rene; Liner, Kevin

2012-01-01

As preservice teachers enter their first teaching experience, they often have perceptions about what teaching will be like based on a vision that is typically linked to their own background and experiences. This study explores the changes in visions of 15 preservice teachers throughout student teaching in an urban environment. The research will…

Augmentation of Cognition and Perception Through Advanced Synthetic Vision Technology

NASA Technical Reports Server (NTRS)

Prinzel, Lawrence J., III; Kramer, Lynda J.; Bailey, Randall E.; Arthur, Jarvis J.; Williams, Steve P.; McNabb, Jennifer

2005-01-01

Synthetic Vision System technology augments reality and creates a virtual visual meteorological condition that extends a pilot's cognitive and perceptual capabilities during flight operations when outside visibility is restricted. The paper describes the NASA Synthetic Vision System for commercial aviation with an emphasis on how the technology achieves Augmented Cognition objectives.

Adolescents with Low Vision: Perceptions of Driving and Nondriving

ERIC Educational Resources Information Center

Sacks, Sharon Zell; Rosenblum, L. Penny

2006-01-01

Two studies examined how adolescents with low vision perceive their ability to drive. The results of both studies indicated similarities in the participants' responses with respect to knowledge of visual impairment, information about options for driving with low vision, frustrations and obstacles imposed by not being able to drive, and independent…

The role of vision in auditory distance perception.

PubMed

Calcagno, Esteban R; Abregú, Ezequiel L; Eguía, Manuel C; Vergara, Ramiro

2012-01-01

In humans, multisensory interaction is an important strategy for improving the detection of stimuli of different nature and reducing the variability of response. It is known that the presence of visual information affects the auditory perception in the horizontal plane (azimuth), but there are few researches that study the influence of vision in the auditory distance perception. In general, the data obtained from these studies are contradictory and do not completely define the way in which visual cues affect the apparent distance of a sound source. Here psychophysical experiments on auditory distance perception in humans are performed, including and excluding visual cues. The results show that the apparent distance from the source is affected by the presence of visual information and that subjects can store in their memory a representation of the environment that later improves the perception of distance.

Eleven Colors That Are Almost Never Confused

NASA Astrophysics Data System (ADS)

Boynton, Robert M.

1989-08-01

1.1. Three functions of color vision. Setting aside the complex psychological effects of color, related to esthetics, fashion, and mood, three relatively basic functions of color vision, which can be examined scientifically, are discernable. (1) With the eye in a given state of adaptation, color vision allows the perception of signals that otherwise would be below threshold, and therefore lost to perception. Evidence for this comes from a variety of two-color threshold experiments. (2) Visible contours can be maintained by color differences alone, regardless of the relative radiances of the two parts of the field whose junction defines the border. For achromatic vision, contour disappears at the isoluminant point. (3) Color specifies what seems to be an absolute property of a surface, one that enhances its recognizability and allows a clearer separation and classification of non-contiguous elements in the visual field.

The effect of response-delay on estimating reachability.

PubMed

Gabbard, Carl; Ammar, Diala

2008-11-01

The experiment was conducted to compare visual imagery (VI) and motor imagery (MI) reaching tasks in a response-delay paradigm designed to explore the hypothesized dissociation between vision for perception and vision for action. Although the visual systems work cooperatively in motor control, theory suggests that they operate under different temporal constraints. From this perspective, we expected that delay would affect MI but not VI because MI operates in real time and VI is postulated to be memory-driven. Following measurement of actual reach, right-handers were presented seven (imagery) targets at midline in eight conditions: MI and VI with 0-, 1-, 2-, and 4-s delays. Results indicted that delay affected the ability to estimate reachability with MI but not with VI. These results are supportive of a general distinction between vision for perception and vision for action.

Automated vision occlusion-timing instrument for perception-action research.

PubMed

Brenton, John; Müller, Sean; Rhodes, Robbie; Finch, Brad

2018-02-01

Vision occlusion spectacles are a highly valuable instrument for visual-perception-action research in a variety of disciplines. In sports, occlusion spectacles have enabled invaluable knowledge to be obtained about the superior capability of experts to use visual information to guide actions within in-situ settings. Triggering the spectacles to occlude a performer's vision at a precise time in an opponent's action or object flight has been problematic, due to experimenter error in using a manual buttonpress approach. This article describes a new laser curtain wireless trigger for vision occlusion spectacles that is portable and fast in terms of its transmission time. The laser curtain can be positioned in a variety of orientations to accept a motion trigger, such as a cricket bowler's arm that distorts the lasers, which then activates a wireless signal for the occlusion spectacles to change from transparent to opaque, which occurs in only 8 ms. Results are reported from calculations done in an electronics laboratory, as well as from tests in a performance laboratory with a cricket bowler and a baseball pitcher, which verified this short time delay before vision occlusion. In addition, our results show that occlusion consistently occurred when it was intended-that is, near ball release and during mid-ball-flight. Only 8% of the collected data trials were unusable. The laser curtain improves upon the limitations of existing vision occlusion spectacle triggers, indicating that it is a valuable instrument for perception-action research in a variety of disciplines.

Tableau de cécité bilatérale à fond d’œil normal révélant un anévrisme non rompu de l'artère cérébrale communicante antérieure

PubMed Central

Ismaili, Abdellah Alaoui; Abdellaoui, Meriem; Khrifi, Zineb; Eddassi, Noureddine; Nejjari, Ourda; Andaloussi, Idriss Benatiya; Tahri, Hicham

2014-01-01

Les anévrysmes intracrâniens non rompu (AICNR) se manifestent le plus souvent par des tableaux cliniques non spécifiques (céphalées, accidents vasculaires ischémiques cérébraux, paralysies des nerfs crâniens) et sont généralement découverts à l'occasion d'imagerie cérébrale pour d'autres raisons. Une cécité bilatérale révélant AICNR de l'artère communicante antérieure est unique dans la littérature. Il s'agit d'un homme de 48 ans sans antécédents médicaux notables qui consulte aux urgences ophtalmologiques pour baisse de l'acuité visuelle rapidement évolutive en une semaine aboutissant à une cécité bilatérale. L'examen ophtalmologique objective une acuité visuelle réduite à la présence d'une perception lumineuse bilatérale avec un bon réflexe photomoteur et le reste de l'examen ophtalmologique qui est strictement normal. Un examen général réalisé en urgence trouve une tension artérielle à 20/14mmHG. L'imagerie cérébrale notamment une tomodensitométrie cérébrale complétée par une imagerie en résonnance magnétique objective un aspect spectaculaire d'un grand anévrisme de l'artère cérébrale communicante antérieure partiellement thrombosé responsable d'une compression isolée du chiasma optique. Après un équilibre de l'hypertension artérielle le patient a été adressé en neurochirurgie pour une thérapeutique en urgence. Un anévrisme est toujours la conséquence d'une modification structurale de la paroi artérielle. Dans leur forme commune, les anévrismes développés sur les artères intracrâniennes sont sacciformes. Ses étiologies sont nombreuses et variées. L’évolution des anévrysmes intracrâniens se fait vers une augmentation de leur volume sous l'influence de facteurs hémodynamiques qui conduit à une fragilisation de leur paroi. Une rupture de l'anévrisme est le mode de découverte le plus fréquent et aussi le plus dramatique. Toute baisse d'acuité visuelle à fond d'oeil normal doit imposer sans retard une imagerie orbito-cérébrale. PMID:25392724

Leader/Follower Behaviour Using the SIFT Algorithm for Object Recognition

DTIC Science & Technology

2006-06-01

opérations de convoiement plus complexes qui utiliseraient une vision artificielle basée sur la détection d’un chef. Les travaux futurs : Étant donné la...Systems: A Virtual Trailer Link Model, In Proceedings of IEEE/RSJ Conference on Intelligent Robots and Systems. [4] Hong, P., Sahli, H., Colon, E., and... Intelligent Robots and Systems. [6] Nguyen, H., Kogut, G., Barua, R., and Burmeister, A. (2004), A Segway RMP-based Robotic Transport System, In In

Identifying and detecting facial expressions of emotion in peripheral vision.

PubMed

Smith, Fraser W; Rossit, Stephanie

2018-01-01

Facial expressions of emotion are signals of high biological value. Whilst recognition of facial expressions has been much studied in central vision, the ability to perceive these signals in peripheral vision has only seen limited research to date, despite the potential adaptive advantages of such perception. In the present experiment, we investigate facial expression recognition and detection performance for each of the basic emotions (plus neutral) at up to 30 degrees of eccentricity. We demonstrate, as expected, a decrease in recognition and detection performance with increasing eccentricity, with happiness and surprised being the best recognized expressions in peripheral vision. In detection however, while happiness and surprised are still well detected, fear is also a well detected expression. We show that fear is a better detected than recognized expression. Our results demonstrate that task constraints shape the perception of expression in peripheral vision and provide novel evidence that detection and recognition rely on partially separate underlying mechanisms, with the latter more dependent on the higher spatial frequency content of the face stimulus.

Identifying and detecting facial expressions of emotion in peripheral vision

PubMed Central

Rossit, Stephanie

2018-01-01

Facial expressions of emotion are signals of high biological value. Whilst recognition of facial expressions has been much studied in central vision, the ability to perceive these signals in peripheral vision has only seen limited research to date, despite the potential adaptive advantages of such perception. In the present experiment, we investigate facial expression recognition and detection performance for each of the basic emotions (plus neutral) at up to 30 degrees of eccentricity. We demonstrate, as expected, a decrease in recognition and detection performance with increasing eccentricity, with happiness and surprised being the best recognized expressions in peripheral vision. In detection however, while happiness and surprised are still well detected, fear is also a well detected expression. We show that fear is a better detected than recognized expression. Our results demonstrate that task constraints shape the perception of expression in peripheral vision and provide novel evidence that detection and recognition rely on partially separate underlying mechanisms, with the latter more dependent on the higher spatial frequency content of the face stimulus. PMID:29847562

D'une ouverture de la voyelle /epsilon/ en finale absolue en francais quebecois : analyse acoustique et perceptive

NASA Astrophysics Data System (ADS)

Riverin-Coutlee, Josiane

Cette contribution est consacree a l'ouverture du /epsilon/ en finale absolue, un phenomene phonetique repute etre en declin en francais quebecois et caracteristique de locuteurs âges, peu scolarises, issus de milieux populaires et s'exprimant en situation de communication informelle. Une analyse acoustique de 480 voyelles /epsilon/ issues de la parole formelle de 40 jeunes etudiants universitaires originaires des centres urbains de Saguenay et de Quebec revele toutefois que le phenomene est encore bien vivant en francais quebecois et qu'il est plus frequent chez les locuteurs de Saguenay, une tendance validee auditivement par accord inter-juges. Les resultats d'un test de discrimination et d'identification mene aupres de 26 etudiants universitaires originaires de ces deux memes villes indiquent que les auditeurs naifs de Saguenay semblent moins sensibles a la variation et moins enclins a juger de l'origine geographique d'un locuteur a partir de sa prononciation de la voyelle /epsilon/ en fin de mot.

Argus II retinal prosthesis system: a review of patient selection criteria, surgical considerations, and post-operative outcomes.

PubMed

Finn, Avni P; Grewal, Dilraj S; Vajzovic, Lejla

2018-01-01

Retinitis pigmentosa (RP) is a group of heterogeneous inherited retinal degenerative disorders characterized by progressive rod and cone dysfunction and ensuing photoreceptor loss. Many patients suffer from legal blindness by their 40s or 50s. Artificial vision is considered once patients have lost all vision to the point of bare light perception or no light perception. The Argus II retinal prosthesis system is one such artificial vision device approved for patients with RP. This review focuses on the factors important for patient selection. Careful pre-operative screening, counseling, and management of patient expectations are critical for the successful implantation and visual rehabilitation of patients with the Argus II device.

Contrasting the use of 2 vision-specific quality of life questionnaires in subjects with open-angle glaucoma.

PubMed

Wren, Patricia A; Musch, David C; Janz, Nancy K; Niziol, Leslie M; Guire, Kenneth E; Gillespie, Brenda W

2009-01-01

To compare 2 vision-specific functional status measures to each other and to clinical parameters in the Collaborative Initial Glaucoma Treatment Study (CIGTS). CIGTS participants completed the Visual Activities Questionnaire (VAQ) and the National Eye Institute-Visual Function Questionnaire (NEI-VFQ) and were tested for visual field (VF) and visual acuity (VA). In all, 426 subjects contributed the VAQ and NEI-VFQ scores at 54 months. Pearson correlations were used to assess associations. The VAQ subscales (range, 0 to 100) that assessed light-dark adaptation (mean=66.1), glare disability (66.4), and acuity/spatial vision (67.7) indicated vision-related functions that CIGTS participants found most difficult. On the NEI-VFQ, subjects reported high levels of visual functioning, with mean >/=90 (out of 100) on the total score and in 9 of 12 subscales. General vision (mean=82.6) received the lowest subscale score. Two subscales common to both questionnaires were highly correlated: VA (r=0.68) and peripheral vision (r=0.77) (both P<0.0001). Correlations between participants' perceptions and clinical measures of visual function were in the expected direction, but weaker. Stronger associations were found between clinical measures and the NEI-VFQ than the VAQ. Better eye VF and worse eye VA had the highest number of significant correlations with subjects' perceptions of their visual function. Increasing VF loss was associated with a significant decrease in the overall and peripheral vision subscale scores from both questionnaires, and also several other subscales. CIGTS patients reported excellent visual function on both the NEI-VFQ and VAQ. These findings will help researchers interested in assessing patients' perceptions of their visual function make an informed selection when choosing between the VAQ and the NEI-VFQ.

L’annonce d’une déficience motrice cérébrale : Une relation de confiance à construire entre les parents, le personnel paramédical et les médecins

PubMed Central

Pelchat, Diane; Lefebvre, Hélène; Bouchard, Jean-Marie

2001-01-01

RÉSUMÉ : L’annonce d’une déficience motrice cérébrale et des incapacités qui en découlent est une situation difficile à vivre pour les parents et les dispensateurs de soins (personnel paramédical et médecins). Un examen de la documentation médicale démontre que depuis vingt ans, le nombre de parents insatisfaits n’a pas changé. L’étude de type qualitatif et exploratoire, effectuée à la demande de milieux de réadaptation, vise à décrire le processus d’annonce d’un diagnostic de déficience motrice cérébrale (DMC) à partir de l’expérience des différents acteurs en cause et à déterminer les facteurs qui facilitent ou compliquent la relation de confiance. Les résultats indiquent que les parents et les dispensateurs de soins vivent dans deux mondes de perception différents au moment de l’annonce, lesquels se rejoignent difficilement. Les parents sont envahis par le drame qu’ils vivent, tandis que les médecins sont concentrés sur le contenu à transmettre aux parents. Cette annonce provoque une importante incertitude qui bloque la communication entre les partenaires, mais elle pourrait devenir un stimulant à de nouvelles stratégies d’adaptation. PMID:20084263

Prise en charge d’un afflux massif de brûles lors d’une situation de catastrophe par incendie au Maroc

PubMed Central

Siah, S.; Hatimi, E.M.; Ihrai, H.; Drissi Kamili, N.

2012-01-01

Summary La brûlure est l’une des lésions les plus fréquemment rencontrées lors de catastrophes naturelles ou lors de catastrophes d’origine humaine (incendies de lieux publics d’origine accidentelle, ou en temps de guerre ou encore lors d’attentats terroristes). La prise en charge et le triage de brûlés en nombre reste un problème difficile; ceci souligne la nécessité d’une réflexion et de prévisions de ces crises en insistant sur la formation des médecins et des soignants. Les défis à relever sont multiples: les soins aux brûlés requièrent un nombre important de personnel qualifié; les évacuations doivent être planifiées en fonction de la gravité de la brûlure et des lésions associées; les stocks et lots de dotation (en particulier en topiques anti-infectieux et en cristalloïdes) doivent être suffisants et adéquats. Les services hospitaliers de l’Hôpital Militaire d’Instruction Mohammed V de Rabat doivent pouvoir être rapidement adaptés pour accueillir et surtout isoler ces patients. L’hypothèse d’une catastrophe par incendie avec afflux massif de brûlés à l’hôpital militaire d’instruction Mohammed V de Rabat ne doit laisser place à aucune improvisation. PMID:23467075

Exploring public perception of non-native species from a visions of nature perspective.

PubMed

Verbrugge, Laura N H; Van den Born, Riyan J G; Lenders, H J Rob

2013-12-01

Not much is known about lay public perceptions of non-native species and their underlying values. Public awareness and engagement, however, are important aspects in invasive species management. In this study, we examined the relations between the lay public's visions of nature, their knowledge about non-native species, and their perceptions of non-native species and invasive species management with a survey administered in the Netherlands. Within this framework, we identified three measures for perception of non-native species: perceived risk, control and engagement. In general, respondents scored moderate values for perceived risk and personal engagement. However, in case of potential ecological or human health risks, control measures were supported. Respondents' images of the human-nature relationship proved to be relevant in engagement in problems caused by invasive species and in recognizing the need for control, while images of nature appeared to be most important in perceiving risks to the environment. We also found that eradication of non-native species was predominantly opposed for species with a high cuddliness factor such as mammals and bird species. We conclude that lay public perceptions of non-native species have to be put in a wider context of visions of nature, and we discuss the implications for public support for invasive species management.

Enhanced operator perception through 3D vision and haptic feedback

NASA Astrophysics Data System (ADS)

Edmondson, Richard; Light, Kenneth; Bodenhamer, Andrew; Bosscher, Paul; Wilkinson, Loren

2012-06-01

Polaris Sensor Technologies (PST) has developed a stereo vision upgrade kit for TALON® robot systems comprised of a replacement gripper camera and a replacement mast zoom camera on the robot, and a replacement display in the Operator Control Unit (OCU). Harris Corporation has developed a haptic manipulation upgrade for TALON® robot systems comprised of a replacement arm and gripper and an OCU that provides haptic (force) feedback. PST and Harris have recently collaborated to integrate the 3D vision system with the haptic manipulation system. In multiple studies done at Fort Leonard Wood, Missouri it has been shown that 3D vision and haptics provide more intuitive perception of complicated scenery and improved robot arm control, allowing for improved mission performance and the potential for reduced time on target. This paper discusses the potential benefits of these enhancements to robotic systems used for the domestic homeland security mission.

An approach to integrate the human vision psychology and perception knowledge into image enhancement

NASA Astrophysics Data System (ADS)

Wang, Hui; Huang, Xifeng; Ping, Jiang

2009-07-01

Image enhancement is very important image preprocessing technology especially when the image is captured in the poor imaging condition or dealing with the high bits image. The benefactor of image enhancement either may be a human observer or a computer vision process performing some kind of higher-level image analysis, such as target detection or scene understanding. One of the main objects of the image enhancement is getting a high dynamic range image and a high contrast degree image for human perception or interpretation. So, it is very necessary to integrate either empirical or statistical human vision psychology and perception knowledge into image enhancement. The human vision psychology and perception claims that humans' perception and response to the intensity fluctuation δu of visual signals are weighted by the background stimulus u, instead of being plainly uniform. There are three main laws: Weber's law, Weber- Fechner's law and Stevens's Law that describe this phenomenon in the psychology and psychophysics. This paper will integrate these three laws of the human vision psychology and perception into a very popular image enhancement algorithm named Adaptive Plateau Equalization (APE). The experiments were done on the high bits star image captured in night scene and the infrared-red image both the static image and the video stream. For the jitter problem in the video stream, this algorithm reduces this problem using the difference between the current frame's plateau value and the previous frame's plateau value to correct the current frame's plateau value. Considering the random noise impacts, the pixel value mapping process is not only depending on the current pixel but the pixels in the window surround the current pixel. The window size is usually 3×3. The process results of this improved algorithms is evaluated by the entropy analysis and visual perception analysis. The experiments' result showed the improved APE algorithms improved the quality of the image, the target and the surrounding assistant targets could be identified easily, and the noise was not amplified much. For the low quality image, these improved algorithms augment the information entropy and improve the image and the video stream aesthetic quality, while for the high quality image they will not debase the quality of the image.

Prevalence of Colour Vision Anomalies Amongst Dental Professionals and its Effect on Shade Matching of Teeth.

PubMed

Khosla, Amrit; Maini, Anuj Paul; Wangoo, Anuj; Singh, Sukhman; Mehar, Damanpreet Kaur

2017-01-01

The success of a restoration is dependent on accurate shade matching of teeth leading to studies evaluating the factors affecting the perception of shades. Colour vision anomalies including colour blindness have been found to exist in the population and it has been thought to be a potential factor affecting the colour perception ability. The present study was done to evaluate the prevalence of colour vision anomalies and its effect on matching of shades of teeth. A total of 147 dental professionals were randomly selected for the study and were first tested for visual acuity using the Snellen's Eye Chart so as to carry on the study with only those operators who had a vision of 6/6. Then, the Ishihara's colour charts were used to test the operators for colour vision handicap. In the last stage of the study, test for accuracy of shade selection was done using the Vitapan Classical shade guide. The shade guide tabs were covered to avoid bias. Percentage was used to calculate the prevalence of colour vision handicap and its effect on matching of shades of teeth as compared to normal vision, which was evaluated using Chi square test. Nineteen operators had colour vision anomalies out of hundred operators and only two operators presented with colour blindness. Colour vision anomaly was more prevalent than colour blindness and it was also found that it was more prevalent in males than females. The difference between the accuracy of shade matching between the operators with normal vision and colour vision defect and operators with normal vision and colour blindness was statistically not significant. Colour blindness and colour vision handicap are rare conditions, with the latter being more common in the population. According to our study, it was concluded that no statistically significant difference existed amongst the operators with normal vision and colour vision anomaly or operators with normal vision and colour blindness during the matching of shades of teeth.

Stereo 3-D Vision in Teaching Physics

ERIC Educational Resources Information Center

Zabunov, Svetoslav

2012-01-01

Stereo 3-D vision is a technology used to present images on a flat surface (screen, paper, etc.) and at the same time to create the notion of three-dimensional spatial perception of the viewed scene. A great number of physical processes are much better understood when viewed in stereo 3-D vision compared to standard flat 2-D presentation. The…

Perceptual geometry of space and form: visual perception of natural scenes and their virtual representation

NASA Astrophysics Data System (ADS)

Assadi, Amir H.

2001-11-01

Perceptual geometry is an emerging field of interdisciplinary research whose objectives focus on study of geometry from the perspective of visual perception, and in turn, apply such geometric findings to the ecological study of vision. Perceptual geometry attempts to answer fundamental questions in perception of form and representation of space through synthesis of cognitive and biological theories of visual perception with geometric theories of the physical world. Perception of form and space are among fundamental problems in vision science. In recent cognitive and computational models of human perception, natural scenes are used systematically as preferred visual stimuli. Among key problems in perception of form and space, we have examined perception of geometry of natural surfaces and curves, e.g. as in the observer's environment. Besides a systematic mathematical foundation for a remarkably general framework, the advantages of the Gestalt theory of natural surfaces include a concrete computational approach to simulate or recreate images whose geometric invariants and quantities might be perceived and estimated by an observer. The latter is at the very foundation of understanding the nature of perception of space and form, and the (computer graphics) problem of rendering scenes to visually invoke virtual presence.

Mechanisms, functions and ecology of colour vision in the honeybee.

PubMed

Hempel de Ibarra, N; Vorobyev, M; Menzel, R

2014-06-01

Research in the honeybee has laid the foundations for our understanding of insect colour vision. The trichromatic colour vision of honeybees shares fundamental properties with primate and human colour perception, such as colour constancy, colour opponency, segregation of colour and brightness coding. Laborious efforts to reconstruct the colour vision pathway in the honeybee have provided detailed descriptions of neural connectivity and the properties of photoreceptors and interneurons in the optic lobes of the bee brain. The modelling of colour perception advanced with the establishment of colour discrimination models that were based on experimental data, the Colour-Opponent Coding and Receptor Noise-Limited models, which are important tools for the quantitative assessment of bee colour vision and colour-guided behaviours. Major insights into the visual ecology of bees have been gained combining behavioural experiments and quantitative modelling, and asking how bee vision has influenced the evolution of flower colours and patterns. Recently research has focussed on the discrimination and categorisation of coloured patterns, colourful scenes and various other groupings of coloured stimuli, highlighting the bees' behavioural flexibility. The identification of perceptual mechanisms remains of fundamental importance for the interpretation of their learning strategies and performance in diverse experimental tasks.

Mechanisms of Percept-Percept and Image-Percept Integration in Vision: Behavioral and Electrophysiological Evidence

ERIC Educational Resources Information Center

Dalvit, Silvia; Eimer, Martin

2011-01-01

Previous research has shown that the detection of a visual target can be guided not only by the temporal integration of two percepts, but also by integrating a percept and an image held in working memory. Behavioral and event-related brain potential (ERP) measures were obtained in a target detection task that required temporal integration of 2…

Refractive Errors Affect the Vividness of Visual Mental Images

PubMed Central

Palermo, Liana; Nori, Raffaella; Piccardi, Laura; Zeri, Fabrizio; Babino, Antonio; Giusberti, Fiorella; Guariglia, Cecilia

2013-01-01

The hypothesis that visual perception and mental imagery are equivalent has never been explored in individuals with vision defects not preventing the visual perception of the world, such as refractive errors. Refractive error (i.e., myopia, hyperopia or astigmatism) is a condition where the refracting system of the eye fails to focus objects sharply on the retina. As a consequence refractive errors cause blurred vision. We subdivided 84 individuals according to their spherical equivalent refraction into Emmetropes (control individuals without refractive errors) and Ametropes (individuals with refractive errors). Participants performed a vividness task and completed a questionnaire that explored their cognitive style of thinking before their vision was checked by an ophthalmologist. Although results showed that Ametropes had less vivid mental images than Emmetropes this did not affect the development of their cognitive style of thinking; in fact, Ametropes were able to use both verbal and visual strategies to acquire and retrieve information. Present data are consistent with the hypothesis of equivalence between imagery and perception. PMID:23755186

Refractive errors affect the vividness of visual mental images.

PubMed

Palermo, Liana; Nori, Raffaella; Piccardi, Laura; Zeri, Fabrizio; Babino, Antonio; Giusberti, Fiorella; Guariglia, Cecilia

2013-01-01

The hypothesis that visual perception and mental imagery are equivalent has never been explored in individuals with vision defects not preventing the visual perception of the world, such as refractive errors. Refractive error (i.e., myopia, hyperopia or astigmatism) is a condition where the refracting system of the eye fails to focus objects sharply on the retina. As a consequence refractive errors cause blurred vision. We subdivided 84 individuals according to their spherical equivalent refraction into Emmetropes (control individuals without refractive errors) and Ametropes (individuals with refractive errors). Participants performed a vividness task and completed a questionnaire that explored their cognitive style of thinking before their vision was checked by an ophthalmologist. Although results showed that Ametropes had less vivid mental images than Emmetropes this did not affect the development of their cognitive style of thinking; in fact, Ametropes were able to use both verbal and visual strategies to acquire and retrieve information. Present data are consistent with the hypothesis of equivalence between imagery and perception.

Soins primaires aux adultes ayant une déficience développementale

PubMed Central

Sullivan, William F.; Berg, Joseph M.; Bradley, Elspeth; Cheetham, Tom; Denton, Richard; Heng, John; Hennen, Brian; Joyce, David; Kelly, Maureen; Korossy, Marika; Lunsky, Yona; McMillan, Shirley

2011-01-01

Résumé Objectif Mettre à jour les lignes directrices canadiennes de 2006 sur les soins primaires aux adultes ayant une déficience développementale (DD) et présenter des recommandations pratiques fondées sur les connaissances actuelles pour traiter des problèmes de santé particuliers chez des adultes ayant une DD. Qualité des preuves Des professionnels de la santé expérimentés participant à un colloque et un groupe de travail subséquent ont discuté et convenu des révisions aux lignes directrices de 2006 en se fondant sur une recherche documentaire exhaustive, la rétroaction obtenue des utilisateurs du guide de pratique et les expériences cliniques personnelles. La plupart des preuves disponibles dans ce domaine viennent de l’opinion d’experts ou de déclarations consensuelles publiées (niveau III). Message principal Les adultes ayant une DD ont des problèmes de santé complexes, dont plusieurs diffèrent de ceux de la population en général. De bons soins primaires permettent d’identifier les problèmes de santé particuliers dont souffrent les adultes ayant une DD pour améliorer leur qualité de vie et leur accès aux soins de santé et prévenir la morbidité et le décès prématuré. Ces lignes directrices résument les problèmes de santé générale, physique, comportementale et mentale des adultes ayant une DD que devraient connaître les professionnels des soins primaires et présentent des recommandations pour le dépistage et la prise en charge en se basant sur les connaissances actuelles que les cliniciens peuvent mettre en pratique. En raison de l’interaction des facteurs biologiques, psychoaffectifs et sociaux qui contribuent à la santé et au bien-être des adultes ayant une DD, ces lignes directrices insistent sur la participation des aidants, l’adaptation des interventions, au besoin, et la consultation auprès de divers professionnels de la santé quand ils sont accessibles. Elles mettent aussi en évidence la nature éthique des soins. Les lignes directrices sont formulées dans le contexte d’un cadre éthique qui tient compte des questions comme le consentement éclairé et l’évaluation des bienfaits pour la santé par rapport aux risques de préjudice. Conclusion La mise en œuvre des lignes directrices proposées ici améliorerait la santé des adultes ayant une DD et minimiserait les disparités sur les plans de la santé et des soins de santé entre les adultes ayant une DD et la population en général.

The role of stereopsis (three-dimensional vision) in dentistry: review of the current literature.

PubMed

Syrimi, M; Ali, N

2015-05-22

Clinical dental work is placing increasing demands on a clinician's vision as new techniques that require fine detail become more common. High hand-eye coordination requires good visual acuity as well as other psychological and neurological qualities such as stereopsis. Stereopsis (three-dimensional vision) is the highest form of depth perception obtained by visual disparity of images formed in the retinas of two eyes. It is believed to confer functional benefits on everyday tasks such as hand-eye coordination. Although its role in depth perception has long been established, little is known regarding the importance of stereopsis in dentistry. This article reviews the role of stereopsis in everyday life and the available literature on the importance of stereopsis in dentistry.

Mise à jour sur la prévention et le dépistage selon l’âge à l’intention des médecins de soins primaires canadiens

PubMed Central

Shimizu, Tawnya; Bouchard, Manon; Mavriplis, Cleo

2016-01-01

Résumé Objectif Faire la synthèse des meilleures lignes directrices fondées sur des données probantes concernant la prévention et le dépistage chez les adultes canadiens selon l’âge. Qualité des données Les recommandations du Groupe d’étude canadien sur les soins de santé préventifs représentent la source principale des renseignements et sont complétées par les recommandations pertinentes du Preventive Services Task Force des États-Unis lorsque celles du Groupe d’étude canadien étaient inaccessibles ou désuètes. Les guides de pratique des principales organisations nationales axées spécifiquement sur une maladie ou une spécialité ont aussi fait l’objet d’une révision pour prendre en compte les données factuelles les plus récentes. Message principal Les interventions de dépistage recommandées selon l’âge et le sexe sont présentées dans un tableau de synthèse où est mise en évidence la qualité des données à l’appui de ces recommandations. Un exemple de modèle à suivre dans les dossiers médicaux électroniques ou sur papier est aussi proposé. Conclusion Qu’il s’agisse d’une visite consacrée à la prévention ou d’une occasion saisie autrement de faire du counseling et du dépistage de prévention chez leurs patients, les médecins de soins primaires peuvent se servir de cette synthèse des recommandations fondées sur des données probantes pour maximiser leur efficience et prévenir d’importantes omissions ou des dépistages inutiles.

Perception and psychological evaluation for visual and auditory environment based on the correlation mechanisms

NASA Astrophysics Data System (ADS)

Fujii, Kenji

2002-06-01

In this dissertation, the correlation mechanism in modeling the process in the visual perception is introduced. It has been well described that the correlation mechanism is effective for describing subjective attributes in auditory perception. The main result is that it is possible to apply the correlation mechanism to the process in temporal vision and spatial vision, as well as in audition. (1) The psychophysical experiment was performed on subjective flicker rates for complex waveforms. A remarkable result is that the phenomenon of missing fundamental is found in temporal vision as analogous to the auditory pitch perception. This implies the existence of correlation mechanism in visual system. (2) For spatial vision, the autocorrelation analysis provides useful measures for describing three primary perceptual properties of visual texture: contrast, coarseness, and regularity. Another experiment showed that the degree of regularity is a salient cue for texture preference judgment. (3) In addition, the autocorrelation function (ACF) and inter-aural cross-correlation function (IACF) were applied for analysis of the temporal and spatial properties of environmental noise. It was confirmed that the acoustical properties of aircraft noise and traffic noise are well described. These analyses provided useful parameters extracted from the ACF and IACF in assessing the subjective annoyance for noise. Thesis advisor: Yoichi Ando Copies of this thesis written in English can be obtained from Junko Atagi, 6813 Mosonou, Saijo-cho, Higashi-Hiroshima 739-0024, Japan. E-mail address: atagi\\@urban.ne.jp.

Vision servo of industrial robot: A review

NASA Astrophysics Data System (ADS)

Zhang, Yujin

2018-04-01

Robot technology has been implemented to various areas of production and life. With the continuous development of robot applications, requirements of the robot are also getting higher and higher. In order to get better perception of the robots, vision sensors have been widely used in industrial robots. In this paper, application directions of industrial robots are reviewed. The development, classification and application of robot vision servo technology are discussed, and the development prospect of industrial robot vision servo technology is proposed.

Refractive Surgery: New Techniques and Usability for Military Personnel (La chirurgie refractive: Nouvelles techniques et leur application pour le personnel militaire)

DTIC Science & Technology

2012-11-01

de loin sans correction, la chirurgie réfractive permet aux jeunes recrues ou militaires du rang de satisfaire aux normes de vision sans...correction exigées pour le métier militaire de leur choix, d’où une augmentation du nombre de candidats et la possibilité pour les individus...réfractive risquent d’engendrer des handicaps visuels et d’écourter des carrières militaires. Pour cette raison, la qualité du service fourni

Aging and Vision

PubMed Central

Owsley, Cynthia

2010-01-01

Given the increasing size of the older adult population in many countries, there is a pressing need to identify the nature of aging-related vision impairments, their underlying mechanisms, and how they impact older adults’ performance of everyday visual tasks. The results of this research can then be used to develop and evaluate interventions to slow or reverse aging-related declines in vision, thereby improving quality of life. Here we summarize salient developments in research on aging and vision over the past 25 years, focusing on spatial contrast sensitivity, vision under low luminance, temporal sensitivity and motion perception, and visual processing speed. PMID:20974168

Multicolour LEDs in educational demonstrations of physics and optometry

NASA Astrophysics Data System (ADS)

Paulins, Paulis; Ozolinsh, Maris

2014-07-01

LED light sources are used to design experimental setup for university courses teaching human color vision. The setup allows to demonstrate various vision characteristics and to apply for student practical exercises to study eye spectral sensitivity in different spectral range using heterochromatic flicker photometry. Technique can be used in laboratory works for students to acquire knowledge in visual perception, basics of electronics and measuring, or it can be applied as fully computer control experiment. Besides studies of the eye spectral sensitivity students can practice in trichromatic color matching and other visual perception tasks

Scanpath-based analysis of objects conspicuity in context of human vision physiology.

PubMed

Augustyniak, Piotr

2007-01-01

This paper discusses principal aspects of objects conspicuity investigated with use of an eye tracker and interpreted on the background of human vision physiology. Proper management of objects conspicuity is fundamental in several leading edge applications in the information society like advertisement, web design, man-machine interfacing and ergonomics. Although some common rules of human perception are applied since centuries in the art, the interest of human perception process is motivated today by the need of gather and maintain the recipient attention by putting selected messages in front of the others. Our research uses the visual tasks methodology and series of progressively modified natural images. The modifying details were attributed by their size, color and position while the scanpath-derived gaze points confirmed or not the act of perception. The statistical analysis yielded the probability of detail perception and correlations with the attributes. This probability conforms to the knowledge about the retina anatomy and perception physiology, although we use noninvasive methods only.

The role of the right hemisphere in form perception and visual gnosis organization.

PubMed

Belyi, B I

1988-06-01

Peculiarities of series of picture interpretations and Rorschach test results in patients with unilateral benign hemispheric tumours are discussed. It is concluded that visual perception in the right hemisphere has hierarchic structure, i.e., each successive area from the occipital lobe towards the frontal having a more complicated function. Visual engrams are distributed over the right hemisphere in a manner similar to the way the visual information is recorded in holographic systems. In any impairment of the right hemisphere a tendency towards whole but unclear vision arises. The preservation of lower levels of visual perception provides for clear vision only of small parts of the image. Thus, confabulatory phenomena arises, which are specific for right hemispheric lesions.

Art, Illusion and the Visual System.

ERIC Educational Resources Information Center

Livingstone, Margaret S.

1988-01-01

Describes the three part system of human vision. Explores the anatomical arrangement of the vision system from the eyes to the brain. Traces the path of various visual signals to their interpretations by the brain. Discusses human visual perception and its implications in art and design. (CW)

Operator-coached machine vision for space telerobotics

NASA Technical Reports Server (NTRS)

Bon, Bruce; Wilcox, Brian; Litwin, Todd; Gennery, Donald B.

1991-01-01

A prototype system for interactive object modeling has been developed and tested. The goal of this effort has been to create a system which would demonstrate the feasibility of high interactive operator-coached machine vision in a realistic task environment, and to provide a testbed for experimentation with various modes of operator interaction. The purpose for such a system is to use human perception where machine vision is difficult, i.e., to segment the scene into objects and to designate their features, and to use machine vision to overcome limitations of human perception, i.e., for accurate measurement of object geometry. The system captures and displays video images from a number of cameras, allows the operator to designate a polyhedral object one edge at a time by moving a 3-D cursor within these images, performs a least-squares fit of the designated edges to edge data detected with a modified Sobel operator, and combines the edges thus detected to form a wire-frame object model that matches the Sobel data.

Perceptions Of School Culture (POSC) User Manual and Technical Report

ERIC Educational Resources Information Center

Cowley, Kimberly S.; Voelkel, Susan; Finch, Nicole L.; Meehan, Merrill L.

2005-01-01

The Perceptions Of School Culture (POSC) instrument was designed to measure the perceptions of a school staff regarding various dimensions of school culture contained in a hypothesized model of school cultural change. Specifically, this model posits that the development of a high-performance learning culture is influenced by school vision and…

A Dynamic Systems Theory Model of Visual Perception Development

ERIC Educational Resources Information Center

Coté, Carol A.

2015-01-01

This article presents a model for understanding the development of visual perception from a dynamic systems theory perspective. It contrasts to a hierarchical or reductionist model that is often found in the occupational therapy literature. In this proposed model vision and ocular motor abilities are not foundational to perception, they are seen…

Modeling the convergence accommodation of stereo vision for binocular endoscopy.

PubMed

Gao, Yuanqian; Li, Jinhua; Li, Jianmin; Wang, Shuxin

2018-02-01

The stereo laparoscope is an important tool for achieving depth perception in robot-assisted minimally invasive surgery (MIS). A dynamic convergence accommodation algorithm is proposed to improve the viewing experience and achieve accurate depth perception. Based on the principle of the human vision system, a positional kinematic model of the binocular view system is established. The imaging plane pair is rectified to ensure that the two rectified virtual optical axes intersect at the fixation target to provide immersive depth perception. Stereo disparity was simulated with the roll and pitch movements of the binocular system. The chessboard test and the endoscopic peg transfer task were performed, and the results demonstrated the improved disparity distribution and robustness of the proposed convergence accommodation method with respect to the position of the fixation target. This method offers a new solution for effective depth perception with the stereo laparoscopes used in robot-assisted MIS. Copyright © 2017 John Wiley & Sons, Ltd.

Do you see what I see? The difference between dog and human visual perception may affect the outcome of experiments.

PubMed

Pongrácz, Péter; Ujvári, Vera; Faragó, Tamás; Miklósi, Ádám; Péter, András

2017-07-01

The visual sense of dogs is in many aspects different than that of humans. Unfortunately, authors do not explicitly take into consideration dog-human differences in visual perception when designing their experiments. With an image manipulation program we altered stationary images, according to the present knowledge about dog-vision. Besides the effect of dogs' dichromatic vision, the software shows the effect of the lower visual acuity and brightness discrimination, too. Fifty adult humans were tested with pictures showing a female experimenter pointing, gazing or glancing to the left or right side. Half of the pictures were shown after they were altered to a setting that approximated dog vision. Participants had difficulty to find out the direction of glancing when the pictures were in dog-vision mode. Glances in dog-vision setting were followed less correctly and with a slower response time than other cues. Our results are the first that show the visual performance of humans under circumstances that model how dogs' weaker vision would affect their responses in an ethological experiment. We urge researchers to take into consideration the differences between perceptual abilities of dogs and humans, by developing visual stimuli that fit more appropriately to dogs' visual capabilities. Copyright © 2017 Elsevier B.V. All rights reserved.

Prevalence of Colour Vision Anomalies Amongst Dental Professionals and its Effect on Shade Matching of Teeth

PubMed Central

Maini, Anuj Paul; Wangoo, Anuj; Singh, Sukhman; Mehar, Damanpreet Kaur

2017-01-01

Abstract Introduction The success of a restoration is dependent on accurate shade matching of teeth leading to studies evaluating the factors affecting the perception of shades. Colour vision anomalies including colour blindness have been found to exist in the population and it has been thought to be a potential factor affecting the colour perception ability. Aim The present study was done to evaluate the prevalence of colour vision anomalies and its effect on matching of shades of teeth. Materials and Methods A total of 147 dental professionals were randomly selected for the study and were first tested for visual acuity using the Snellen’s Eye Chart so as to carry on the study with only those operators who had a vision of 6/6. Then, the Ishihara’s colour charts were used to test the operators for colour vision handicap. In the last stage of the study, test for accuracy of shade selection was done using the Vitapan Classical shade guide. The shade guide tabs were covered to avoid bias. Percentage was used to calculate the prevalence of colour vision handicap and its effect on matching of shades of teeth as compared to normal vision, which was evaluated using Chi square test. Results Nineteen operators had colour vision anomalies out of hundred operators and only two operators presented with colour blindness. Colour vision anomaly was more prevalent than colour blindness and it was also found that it was more prevalent in males than females. The difference between the accuracy of shade matching between the operators with normal vision and colour vision defect and operators with normal vision and colour blindness was statistically not significant. Conclusion Colour blindness and colour vision handicap are rare conditions, with the latter being more common in the population. According to our study, it was concluded that no statistically significant difference existed amongst the operators with normal vision and colour vision anomaly or operators with normal vision and colour blindness during the matching of shades of teeth. PMID:28274040

An Evaluation of a Two Week Teaching Trial Using Interactive Video Technology: Perceptions of Students and Staff.

ERIC Educational Resources Information Center

Baker, R. A.; Hansford, B. C.

This report is concerned with an evaluation of a 2-week teaching trial in 1989 that utilized compressed data--interactive video technology. The trial was a collaborative venture of the University of New England (UNE), TELECOM, the Department of Education, Employment and Training (DEET), and SONY. In general, the University of New England supplied…

Visual speech perception in foveal and extrafoveal vision: further implications for divisions in hemispheric projections.

PubMed

Jordan, Timothy R; Sheen, Mercedes; Abedipour, Lily; Paterson, Kevin B

2014-01-01

When observing a talking face, it has often been argued that visual speech to the left and right of fixation may produce differences in performance due to divided projections to the two cerebral hemispheres. However, while it seems likely that such a division in hemispheric projections exists for areas away from fixation, the nature and existence of a functional division in visual speech perception at the foveal midline remains to be determined. We investigated this issue by presenting visual speech in matched hemiface displays to the left and right of a central fixation point, either exactly abutting the foveal midline or else located away from the midline in extrafoveal vision. The location of displays relative to the foveal midline was controlled precisely using an automated, gaze-contingent eye-tracking procedure. Visual speech perception showed a clear right hemifield advantage when presented in extrafoveal locations but no hemifield advantage (left or right) when presented abutting the foveal midline. Thus, while visual speech observed in extrafoveal vision appears to benefit from unilateral projections to left-hemisphere processes, no evidence was obtained to indicate that a functional division exists when visual speech is observed around the point of fixation. Implications of these findings for understanding visual speech perception and the nature of functional divisions in hemispheric projection are discussed.

Sharpening vision by adapting to flicker.

PubMed

Arnold, Derek H; Williams, Jeremy D; Phipps, Natasha E; Goodale, Melvyn A

2016-11-01

Human vision is surprisingly malleable. A static stimulus can seem to move after prolonged exposure to movement (the motion aftereffect), and exposure to tilted lines can make vertical lines seem oppositely tilted (the tilt aftereffect). The paradigm used to induce such distortions (adaptation) can provide powerful insights into the computations underlying human visual experience. Previously spatial form and stimulus dynamics were thought to be encoded independently, but here we show that adaptation to stimulus dynamics can sharpen form perception. We find that fast flicker adaptation (FFAd) shifts the tuning of face perception to higher spatial frequencies, enhances the acuity of spatial vision-allowing people to localize inputs with greater precision and to read finer scaled text, and it selectively reduces sensitivity to coarse-scale form signals. These findings are consistent with two interrelated influences: FFAd reduces the responsiveness of magnocellular neurons (which are important for encoding dynamics, but can have poor spatial resolution), and magnocellular responses contribute coarse spatial scale information when the visual system synthesizes form signals. Consequently, when magnocellular responses are mitigated via FFAd, human form perception is transiently sharpened because "blur" signals are mitigated.

Experience-driven plasticity in binocular vision

PubMed Central

Klink, P. Christiaan; Brascamp, Jan W.; Blake, Randolph; van Wezel, Richard J.A.

2010-01-01

Summary Experience-driven neuronal plasticity allows the brain to adapt its functional connectivity to recent sensory input. Here we use binocular rivalry [1], an experimental paradigm where conflicting images are presented to the individual eyes, to demonstrate plasticity in the neuronal mechanisms that convert visual information from two separated retinas into single perceptual experiences. Perception during binocular rivalry tended to initially consist of alternations between exclusive representations of monocularly defined images, but upon prolonged exposure, mixture percepts became more prevalent. The completeness of suppression, reflected in the incidence of mixture percepts, plausibly reflects the strength of inhibition that likely plays a role in binocular rivalry [2]. Recovery of exclusivity was possible, but required highly specific binocular stimulation. Documenting the prerequisites for these observed changes in perceptual exclusivity, our experiments suggest experience-driven plasticity at interocular inhibitory synapses, driven by the (lack of) correlated activity of neurons representing the conflicting stimuli. This form of plasticity is consistent with a previously proposed, but largely untested, anti-Hebbian learning mechanism for inhibitory synapses in vision [3, 4]. Our results implicate experience-driven plasticity as one governing principle in the neuronal organization of binocular vision. PMID:20674360

Driving and the Disabled Teenager: What Every Parent Should Know.

ERIC Educational Resources Information Center

Exceptional Parent, 1986

1986-01-01

Assessment of teenagers with disabilities to determine their ability to learn to drive focuses on vision and perception, auditory perception, reaction time, judgment, need for adaptive aids, and use of a car or specially equipped van. (CL)

Knowledge-based machine vision systems for space station automation

NASA Technical Reports Server (NTRS)

Ranganath, Heggere S.; Chipman, Laure J.

1989-01-01

Computer vision techniques which have the potential for use on the space station and related applications are assessed. A knowledge-based vision system (expert vision system) and the development of a demonstration system for it are described. This system implements some of the capabilities that would be necessary in a machine vision system for the robot arm of the laboratory module in the space station. A Perceptics 9200e image processor, on a host VAXstation, was used to develop the demonstration system. In order to use realistic test images, photographs of actual space shuttle simulator panels were used. The system's capabilities of scene identification and scene matching are discussed.

Optic ataxia and the function of the dorsal stream: contributions to perception and action.

PubMed

Pisella, Laure; Sergio, Lauren; Blangero, Annabelle; Torchin, Héloïse; Vighetto, Alain; Rossetti, Yves

2009-12-01

Optic ataxia (OA) is one of the symptoms pertaining to Bálint's Syndrome. It has been described clinically for nearly 80 years before it became a cornerstone of the most popular dual stream theory of the visual brain. Over the last 10 years a regain of interest for this neurological condition lead to a number of precise analyses of the deficits found in optic ataxia, giving rise to a renewed outline of its very definition and hence of the function(s) of the occipito-parietal (dorsal) stream. In absence of concomitant clinical symptoms, we review evidence that misreaching errors in central vision result from the "hand effect": an erroneous dynamic spatial processing of proprioceptive information from the hand. When visual feedback of the hand is provided (closed-loop condition), pure optic ataxia is restricted to peripheral vision. This central versus peripheral vision distinction is repeatedly used to argue that action and perception are not unique and dissociated systems. New assessments of optic ataxia patients are provided, confirming on one hand that their visuomotor deficit is specific to peripheral vision (i.e. when the gaze and the hand goals are dissociated), on the other hand that they disclose perceptual deficits in peripheral vision. These results are coherent with the recent demonstration that optic ataxia patients exhibit a general contralesional deficit for dynamic visuo-spatial processing, affecting both hand and eye movements [Gaveau, V., Pélisson, D., Blangero, A., Urquizar, C., Prablanc, C.,Vighetto, A., et al. (2008). A common parietal module for saccade and reach: Eye-hand coordination and saccadic control in optic ataxia. Neuropsychologia, 46, 475-486]. Such module(s) within the dorsal stream could be used for both action and perception in the periphery. It is concluded that optic ataxia cannot be considered as a unitary and specific visuo-manual deficit, and that the modular organisation of the dorsal stream allows for numerous dorsal-ventral interactions for perception and action.

Development in the Understanding of Perception: The Decline of Extramission Perception Beliefs.

ERIC Educational Resources Information Center

Cottrell, Jane E.; Winer, Gerald A.

1994-01-01

Ancient philosophers, such as Plato and Euclid, believed in an extramission theory of visual perception, which held that there are emissions from the eyes during the act of vision. Three studies, comparing college and elementary school students, found a decrease over age in the belief in extramission and an increase in the belief that vision…

Stereoscopic Perception of Women in Real and Virtual Environments: A Study towards Educational Neuroscience

ERIC Educational Resources Information Center

Zacharis, Georgios S.; Mikropoulos, Tassos A.; Priovolou, Chryssi

2013-01-01

Previous studies report the involvement of specific brain activation in stereoscopic vision and the perception of depth information. This work presents the first comparative results of adult women on the effects of stereoscopic perception in three different static environments; a real, a two dimensional (2D) and a stereoscopic three dimensional…

Emotion-Induced Trade-Offs in Spatiotemporal Vision

ERIC Educational Resources Information Center

Bocanegra, Bruno R.; Zeelenberg, Rene

2011-01-01

It is generally assumed that emotion facilitates human vision in order to promote adaptive responses to a potential threat in the environment. Surprisingly, we recently found that emotion in some cases impairs the perception of elementary visual features (Bocanegra & Zeelenberg, 2009b). Here, we demonstrate that emotion improves fast temporal…

Teacher Vision: Expert and Novice Teachers' Perception of Problematic Classroom Management Scenes

ERIC Educational Resources Information Center

Wolff, Charlotte E.; Jarodzka, Halszka; van den Bogert, Niek; Boshuizen, Henny P. A.

2016-01-01

Visual expertise has been explored in numerous professions, but research on teachers' vision remains limited. Teachers' visual expertise is an important professional skill, particularly the ability to simultaneously perceive and interpret classroom situations for effective classroom management. This skill is complex and relies on an awareness of…

Faculty Perceptions of Strategic Visioning.

ERIC Educational Resources Information Center

Marcus, Laurence R.; Smith, Richard

This report presents an examination of the use of a participative model in the strategic planning process at a publicly-supported, comprehensive institution in the middle Atlantic region of the United States. Specific attention is given to the process of developing the vision statement, an undertaking of approximately 15 months preceding Board of…

The Difference that Age Makes: Cultural Factors that Shape Older Adults' Responses to Age-Related Macular Degeneration

ERIC Educational Resources Information Center

Mogk, Marja

2008-01-01

This article suggests that approaching vision loss from age-related macular degeneration from a sociocultural perspective, specifically considering perceptions of aging, blindness, disability, and generational viewpoints and norms, may be critical to understanding older adults' responses to vision loss and visual rehabilitation.

Active vision in satellite scene analysis

NASA Technical Reports Server (NTRS)

Naillon, Martine

1994-01-01

In earth observation or planetary exploration it is necessary to have more and, more autonomous systems, able to adapt to unpredictable situations. This imposes the use, in artificial systems, of new concepts in cognition, based on the fact that perception should not be separated from recognition and decision making levels. This means that low level signal processing (perception level) should interact with symbolic and high level processing (decision level). This paper is going to describe the new concept of active vision, implemented in Distributed Artificial Intelligence by Dassault Aviation following a 'structuralist' principle. An application to spatial image interpretation is given, oriented toward flexible robotics.

Vision for perception and vision for action: normal and unusual development.

PubMed

Dilks, Daniel D; Hoffman, James E; Landau, Barbara

2008-07-01

Evidence suggests that visual processing is divided into the dorsal ('how') and ventral ('what') streams. We examined the normal development of these streams and their breakdown under neurological deficit by comparing performance of normally developing children and Williams syndrome individuals on two tasks: a visually guided action ('how') task, in which participants posted a card into an oriented slot, and a perception ('what') task, in which they matched a card to the slot's orientation. Results showed that all groups performed worse on the action task than the perception task, but the disparity was more pronounced in WS individuals and in normal 3-4-year-olds than in older children. These findings suggest that the 'how' system may be relatively slow to develop and more vulnerable to breakdown than the 'what' system.

Slow angled-descent forepaw grasping (SLAG): an innate behavioral task for identification of individual experimental mice possessing functional vision.

PubMed

Gil-Pagés, Macarena; Stiles, Robert J; Parks, Christopher A; Neier, Steven C; Radulovic, Maja; Oliveros, Alfredo; Ferrer, Alejandro; Reed, Brendan K; Wilton, Katelynn M; Schrum, Adam G

2013-08-23

There is significant interest in the generation of improved assays to clearly identify experimental mice possessing functional vision, a property that could qualify mice for inclusion in behavioral and neuroscience studies. Widely employed current methods rely on mouse responses to visual cues in assays of reflexes, depth perception, or cognitive memory. However, commonly assessed mouse reflexes can sometimes be ambiguous in their expression, while depth perception assays are sometimes confounded by variation in anxiety responses and exploratory conduct. Furthermore, in situations where experimental groups vary in their cognitive memory capacity, memory assays may not be ideal for assessing differences in vision. We have optimized a non-invasive behavioral assay that relies on an untrained, innate response to identify individual experimental mice possessing functional vision: slow angled-descent forepaw grasping (SLAG). First, we verified that SLAG performance depends on vision and not olfaction. Next, all members of an age-ranged cohort of 158 C57BL/6 mice (57 wild-type, 101 knockout, age range 44-241 days) were assessed for functional vision using the SLAG test without training or conditioning. Subjecting the population to a second innate behavioral test, Dark Chamber preference, corroborated that the functional vision assessment of SLAG was valid. We propose that the SLAG assay is immediately useful to quickly and clearly identify experimental mice possessing functional vision. SLAG is based on a behavioral readout with a significant innate component with no requirement for training. This will facilitate the selection of mice of known sighted status in vision-dependent experiments that focus on other types of behavior, neuroscience, and/or cognitive memory.

Slow angled-descent forepaw grasping (SLAG): an innate behavioral task for identification of individual experimental mice possessing functional vision

PubMed Central

2013-01-01

Background There is significant interest in the generation of improved assays to clearly identify experimental mice possessing functional vision, a property that could qualify mice for inclusion in behavioral and neuroscience studies. Widely employed current methods rely on mouse responses to visual cues in assays of reflexes, depth perception, or cognitive memory. However, commonly assessed mouse reflexes can sometimes be ambiguous in their expression, while depth perception assays are sometimes confounded by variation in anxiety responses and exploratory conduct. Furthermore, in situations where experimental groups vary in their cognitive memory capacity, memory assays may not be ideal for assessing differences in vision. Results We have optimized a non-invasive behavioral assay that relies on an untrained, innate response to identify individual experimental mice possessing functional vision: slow angled-descent forepaw grasping (SLAG). First, we verified that SLAG performance depends on vision and not olfaction. Next, all members of an age-ranged cohort of 158 C57BL/6 mice (57 wild-type, 101 knockout, age range 44–241 days) were assessed for functional vision using the SLAG test without training or conditioning. Subjecting the population to a second innate behavioral test, Dark Chamber preference, corroborated that the functional vision assessment of SLAG was valid. Conclusions We propose that the SLAG assay is immediately useful to quickly and clearly identify experimental mice possessing functional vision. SLAG is based on a behavioral readout with a significant innate component with no requirement for training. This will facilitate the selection of mice of known sighted status in vision-dependent experiments that focus on other types of behavior, neuroscience, and/or cognitive memory. PMID:23971729

Répercussions psychosociales de la drépanocytose sur les parents d'enfants vivant à Kinshasa, République Démocratique du Congo: une étude qualitative

PubMed Central

Luboya, Evariste; Tshilonda, Jean-Christophe Bukasa; Ekila, Mathilde Bothale; Aloni, Michel Ntetani

2014-01-01

Introduction L'insuffisance des moyens de base pour le dépistage et la prise en charge de la socioculturel Africain. D'où la nécessité de réaliser un travail de mise en sens du vécu et des émotions en vue d'information et de soutien psychologique des familles des drépanocytaires. Cette étude a eu pour objectif d'identifier la nature des répercussions psychosociales de la drépanocytose chez les parents et chez les malades. Méthodes Une approche qualitative a été utilisée. Des entretiens ont été menés auprès des parents et des patients drépanocytaires. Nos résultats ont fait l'objet d'une analyse thématique articulée sur les circonstances de découvertes de la maladie, les répercussions de la maladie et la perception de la prise en charge. Résultats Nos interviews ont montré des répercussions psychosociales importantes chez les parents d'enfants drépanocytaires et de stigmatisation des difficultés d'insertion sociale et scolaire pour les enfants drépanocytaires. Ces derniers sont les grands oubliés des récits de parents. La prise en charge est uniquement médicale avec des ressources très limitées et aucun accompagnement psychologique de la famille n'est assuré. Conclusion La prise en charge de cette maladie nécessite la mise en place d'une politique de prise en charge basée sur une approche globale de la maladie. PMID:25574334

Low vision in east African blind school students: need for optical low vision services.

PubMed

Silver, J; Gilbert, C E; Spoerer, P; Foster, A

1995-09-01

There is increasing awareness of the needs of children with low vision, particularly in developing countries where programmes of integrated education are being developed. However, appropriate low vision services are usually not available or affordable. The aims of this study were, firstly, to assess the need for spectacles and optical low vision devices in students with low vision in schools for the blind in Kenya and Uganda; secondly, to evaluate inexpensive locally produced low vision devices; and, finally, to evaluate simple methods of identifying those low vision students who could read N5 to N8 print after low vision assessment. A total of 230 students were examined (51 school and 16 university students in Uganda and 163 students in Kenya, aged 5-22 years), 147 of whom had a visual acuity of less than 6/18 to perception of light in the better eye at presentation. After refraction seven of the 147 achieved 6/18 or better. Eighty two (58.6%) of the 140 students with low vision (corrected visual acuity in the better eye of less than 6/18 to light perception) had refractive errors of more than 2 dioptres in the better eye, and 38 (27.1%) had more than 2 dioptres of astigmatism. Forty six per cent of students with low vision (n = 64) could read N5-N8 print unaided or with spectacles, as could a further 33% (n = 46) with low vision devices. Low vision devices were indicated in a total of 50 students (35.7%). The locally manufactured devices could meet two thirds of the need. A corrected distance acuity of 1/60 or better had a sensitivity of 99.1% and a specificity of 56.7% in predicting the ability to discern N8 print or better. The ability to perform at least two of the three simple tests of functional vision had a sensitivity of 95.5% and a specificity of 63.3% in identifying the students able to discern N8 or better.

No Evidence of Narrowly Defined Cognitive Penetrability in Unambiguous Vision

PubMed Central

Lammers, Nikki A.; de Haan, Edward H.; Pinto, Yair

2017-01-01

The classical notion of cognitive impenetrability suggests that perceptual processing is an automatic modular system and not under conscious control. Near consensus is now emerging that this classical notion is untenable. However, as recently pointed out by Firestone and Scholl, this consensus is built on quicksand. In most studies claiming perception is cognitively penetrable, it remains unclear which actual process has been affected (perception, memory, imagery, input selection or judgment). In fact, the only available “proofs” for cognitive penetrability are proxies for perception, such as behavioral responses and neural correlates. We suggest that one can interpret cognitive penetrability in two different ways, a broad sense and a narrow sense. In the broad sense, attention and memory are not considered as “just” pre- and post-perceptual systems but as part of the mechanisms by which top-down processes influence the actual percept. Although many studies have proven top-down influences in this broader sense, it is still debatable whether cognitive penetrability remains tenable in a narrow sense. The narrow sense states that cognitive penetrability only occurs when top-down factors are flexible and cause a clear illusion from a first person perspective. So far, there is no strong evidence from a first person perspective that visual illusions can indeed be driven by high-level flexible factors. One cannot be cognitively trained to see and unsee visual illusions. We argue that this lack of convincing proof for cognitive penetrability in the narrow sense can be explained by the fact that most research focuses on foveal vision only. This type of perception may be too unambiguous for transient high-level factors to control perception. Therefore, illusions in more ambiguous perception, such as peripheral vision, can offer a unique insight into the matter. They produce a clear subjective percept based on unclear, degraded visual input: the optimal basis to study narrowly defined cognitive penetrability. PMID:28740471

Global motion perception is associated with motor function in 2-year-old children.

PubMed

Thompson, Benjamin; McKinlay, Christopher J D; Chakraborty, Arijit; Anstice, Nicola S; Jacobs, Robert J; Paudel, Nabin; Yu, Tzu-Ying; Ansell, Judith M; Wouldes, Trecia A; Harding, Jane E

2017-09-29

The dorsal visual processing stream that includes V1, motion sensitive area V5 and the posterior parietal lobe, supports visually guided motor function. Two recent studies have reported associations between global motion perception, a behavioural measure of processing in V5, and motor function in pre-school and school aged children. This indicates a relationship between visual and motor development and also supports the use of global motion perception to assess overall dorsal stream function in studies of human neurodevelopment. We investigated whether associations between vision and motor function were present at 2 years of age, a substantially earlier stage of development. The Bayley III test of Infant and Toddler Development and measures of vision including visual acuity (Cardiff Acuity Cards), stereopsis (Lang stereotest) and global motion perception were attempted in 404 2-year-old children (±4 weeks). Global motion perception (quantified as a motion coherence threshold) was assessed by observing optokinetic nystagmus in response to random dot kinematograms of varying coherence. Linear regression revealed that global motion perception was modestly, but statistically significantly associated with Bayley III composite motor (r 2 =0.06, P<0.001, n=375) and gross motor scores (r 2 =0.06, p<0.001, n=375). The associations remained significant when language score was included in the regression model. In addition, when language score was included in the model, stereopsis was significantly associated with composite motor and fine motor scores, but unaided visual acuity was not statistically significantly associated with any of the motor scores. These results demonstrate that global motion perception and binocular vision are associated with motor function at an early stage of development. Global motion perception can be used as a partial measure of dorsal stream function from early childhood. Copyright © 2017 Elsevier B.V. All rights reserved.

Landmark navigation and autonomous landing approach with obstacle detection for aircraft

NASA Astrophysics Data System (ADS)

Fuerst, Simon; Werner, Stefan; Dickmanns, Dirk; Dickmanns, Ernst D.

1997-06-01

A machine perception system for aircraft and helicopters using multiple sensor data for state estimation is presented. By combining conventional aircraft sensor like gyros, accelerometers, artificial horizon, aerodynamic measuring devices and GPS with vision data taken by conventional CCD-cameras mounted on a pan and tilt platform, the position of the craft can be determined as well as the relative position to runways and natural landmarks. The vision data of natural landmarks are used to improve position estimates during autonomous missions. A built-in landmark management module decides which landmark should be focused on by the vision system, depending on the distance to the landmark and the aspect conditions. More complex landmarks like runways are modeled with different levels of detail that are activated dependent on range. A supervisor process compares vision data and GPS data to detect mistracking of the vision system e.g. due to poor visibility and tries to reinitialize the vision system or to set focus on another landmark available. During landing approach obstacles like trucks and airplanes can be detected on the runway. The system has been tested in real-time within a hardware-in-the-loop simulation. Simulated aircraft measurements corrupted by noise and other characteristic sensor errors have been fed into the machine perception system; the image processing module for relative state estimation was driven by computer generated imagery. Results from real-time simulation runs are given.

Vision and falls in older people: risk factors and intervention strategies.

PubMed

Lord, Stephen R; Smith, Stuart T; Menant, Jasmine C

2010-11-01

Poor vision impairs balance and increases the risk of falls and fractures in older people. Multifocal glasses can add to this risk by impairing contrast sensitivity, depth perception, and ability to negotiate obstacles. Vision assessment and provision of new spectacles may not reduce, and may even increase, the risk of falls. Restriction of the use of multifocal glasses may reduce falls in active older people. Other effective fall prevention strategies include maximizing vision through cataract surgery and occupational therapy interventions in visually impaired older people. Copyright © 2010 Elsevier Inc. All rights reserved.

Preparing Mathematics Teachers for Elementary High-Poverty Schools: Perceptions and Suggestions from Preservice Teachers

ERIC Educational Resources Information Center

McKinney, Sueanne E.; Berry, Robert Q., III; Jackson, Joan M.

2007-01-01

The National Council of Teachers of Mathematics articulates an ambitious vision of a high-quality mathematics program. Achieving this vision requires competent and knowledgeable teachers who can support all students in learning mathematics concepts with understanding. Effective mathematics teachers are especially needed for high-poverty schools…

The Effectiveness of Two Programs To Develop Visual Perception in Spanish Schoolchildren with Low Vision.

ERIC Educational Resources Information Center

Lopez-Justicia, Maria D.; Martos, Francisco J.

1999-01-01

This study compared improvements in visual function of 20 Spanish children with low vision, ages 4 to 6 years. Children received either the Barraga and Morris program or the Frostig program, or placebo control or no treatment. No significant differences between treatment groups were found. (DB)

Children's Use of Allocentric Cues in Visually- and Memory-Guided Reach Space

ERIC Educational Resources Information Center

Cordova, Alberto; Gabbard, Carl

2012-01-01

Theory suggests that the vision-for-perception and vision-for-action processing streams operate under very different temporal constraints (Glover, 2004; Goodale, Jackobson, & Keillor, 1994; Graham, Bradshaw, & Davis, 1998; Hu, Eagleson, & Goodale, 1999). With the present study, children and young adults were asked to estimate how far a cued target…

Visual function and color vision in adults with Attention-Deficit/Hyperactivity Disorder.

PubMed

Kim, Soyeon; Chen, Samantha; Tannock, Rosemary

2014-01-01

Color vision and self-reported visual function in everyday life in young adults with Attention-Deficit/Hyperactivity Disorder (ADHD) were investigated. Participants were 30 young adults with ADHD and 30 controls matched for age and gender. They were tested individually and completed the Visual Activities Questionnaire (VAQ), Farnsworth-Munsell 100 Hue Test (FMT) and A Quick Test of Cognitive Speed (AQT). The ADHD group reported significantly more problems in 4 of 8 areas on the VAQ: depth perception, peripheral vision, visual search and visual processing speed. Further analyses of VAQ items revealed that the ADHD group endorsed more visual problems associated with driving than controls. Color perception difficulties on the FMT were restricted to the blue spectrum in the ADHD group. FMT and AQT results revealed slower processing of visual stimuli in the ADHD group. A comprehensive investigation of mechanisms underlying visual function and color vision in adults with ADHD is warranted, along with the potential impact of these visual problems on driving performance. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

The functional subdivision of the visual brain: Is there a real illusion effect on action? A multi-lab replication study.

PubMed

Kopiske, Karl K; Bruno, Nicola; Hesse, Constanze; Schenk, Thomas; Franz, Volker H

2016-06-01

It has often been suggested that visual illusions affect perception but not actions such as grasping, as predicted by the "two-visual-systems" hypothesis of Milner and Goodale (1995, The Visual Brain in Action, Oxford University press). However, at least for the Ebbinghaus illusion, relevant studies seem to reveal a consistent illusion effect on grasping (Franz & Gegenfurtner, 2008. Grasping visual illusions: consistent data and no dissociation. Cognitive Neuropsychology). Two interpretations are possible: either grasping is not immune to illusions (arguing against dissociable processing mechanisms for vision-for-perception and vision-for-action), or some other factors modulate grasping in ways that mimic a vision-for perception effect in actions. It has been suggested that one such factor may be obstacle avoidance (Haffenden Schiff & Goodale, 2001. The dissociation between perception and action in the Ebbinghaus illusion: nonillusory effects of pictorial cues on grasp. Current Biology, 11, 177-181). In four different labs (total N = 144), we conducted an exact replication of previous studies suggesting obstacle avoidance mechanisms, implementing conditions that tested grasping as well as multiple perceptual tasks. This replication was supplemented by additional conditions to obtain more conclusive results. Our results confirm that grasping is affected by the Ebbinghaus illusion and demonstrate that this effect cannot be explained by obstacle avoidance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Préoccupations de carrière chez les médecins de travail des groupements de Médecine de travail en Tunisie

PubMed Central

Merchaoui, Irtyah; Chouchène, Asma; Bouanène, Ines; Chaari, Néila; Zrafi, Wassim; Henchi, Adnène; Akrout, Mohamed; Amri, Charfeddine

2017-01-01

Introduction L'insatisfaction de carrière des médecins de travail (MT) peut influencer leur performance et la qualité des prestations fournies. L'objectif de notre étude est d'évaluer la satisfaction au travail des MT du terrain de l'ensemble des Groupements de médecine de travail (GMT) de la Tunisie et préciser les facteurs déterminants. Méthodes Il s'agit d'une étude nationale transversale portant sur les MT de 22 GMT, basée sur le questionnaire, validé SAPHORA JOB. Résultats 58% des MT des GMT étaient insatisfaits de leur carrière. La satisfaction de carrière était statistiquement influencée par le nombre d'entreprises en charge (p=0,016), l'organisation du travail (p=0,010),le ressenti du métier (p=0,011),le salaire (p‹10-3) et l'information sur la réglementation en vigueur (p=0,047). Conclusion L'homogénéisation des grilles salariales et des échelons de carrière des MT des GMT basée sur une révision des textes législatifs est indiquée. L'amélioration de l'organisation et des conditions de travail peut permettre un épanouissement au travail et une amélioration des prestations. PMID:28819472

Disturbed temporal dynamics of brain synchronization in vision loss.

PubMed

Bola, Michał; Gall, Carolin; Sabel, Bernhard A

2015-06-01

Damage along the visual pathway prevents bottom-up visual input from reaching further processing stages and consequently leads to loss of vision. But perception is not a simple bottom-up process - rather it emerges from activity of widespread cortical networks which coordinate visual processing in space and time. Here we set out to study how vision loss affects activity of brain visual networks and how networks' activity is related to perception. Specifically, we focused on studying temporal patterns of brain activity. To this end, resting-state eyes-closed EEG was recorded from partially blind patients suffering from chronic retina and/or optic-nerve damage (n = 19) and healthy controls (n = 13). Amplitude (power) of oscillatory activity and phase locking value (PLV) were used as measures of local and distant synchronization, respectively. Synchronization time series were created for the low- (7-9 Hz) and high-alpha band (11-13 Hz) and analyzed with three measures of temporal patterns: (i) length of synchronized-/desynchronized-periods, (ii) Higuchi Fractal Dimension (HFD), and (iii) Detrended Fluctuation Analysis (DFA). We revealed that patients exhibit less complex, more random and noise-like temporal dynamics of high-alpha band activity. More random temporal patterns were associated with worse performance in static (r = -.54, p = .017) and kinetic perimetry (r = .47, p = .041). We conclude that disturbed temporal patterns of neural synchronization in vision loss patients indicate disrupted communication within brain visual networks caused by prolonged deafferentation. We propose that because the state of brain networks is essential for normal perception, impaired brain synchronization in patients with vision loss might aggravate the functional consequences of reduced visual input. Copyright © 2015 Elsevier Ltd. All rights reserved.

Texture and art with deep neural networks.

PubMed

Gatys, Leon A; Ecker, Alexander S; Bethge, Matthias

2017-10-01

Although the study of biological vision and computer vision attempt to understand powerful visual information processing from different angles, they have a long history of informing each other. Recent advances in texture synthesis that were motivated by visual neuroscience have led to a substantial advance in image synthesis and manipulation in computer vision using convolutional neural networks (CNNs). Here, we review these recent advances and discuss how they can in turn inspire new research in visual perception and computational neuroscience. Copyright © 2017. Published by Elsevier Ltd.

Crepuscular and Nocturnal Illumination and Its Effects on Color Perception by the Nocturnal Hawkmoth Deilephila elpenor

DTIC Science & Technology

2006-01-01

vision may enhance recognition of conspecifics or be used in mating. While mating in moths is thought to be entirely mediated by olfaction , most tasks are...time, unambiguous evidence for true color vision under scotopic conditions has only recently been acquired (Kelber et al., 2002; Roth and Kelber, 2004...color under starlight and dim moonlight, respectively, raise at least two issues. First, what is the selective advantage of color vision in these

The contribution of LM to the neuroscience of movement vision

PubMed Central

Zihl, Josef; Heywood, Charles A.

2015-01-01

The significance of early and sporadic reports in the 19th century of impairments of motion vision following brain damage was largely unrecognized. In the absence of satisfactory post-mortem evidence, impairments were interpreted as the consequence of a more general disturbance resulting from brain damage, the location and extent of which was unknown. Moreover, evidence that movement constituted a special visual perception and may be selectively spared was similarly dismissed. Such skepticism derived from a reluctance to acknowledge that the neural substrates of visual perception may not be confined to primary visual cortex. This view did not persist. First, it was realized that visual movement perception does not depend simply on the analysis of spatial displacements and temporal intervals, but represents a specific visual movement sensation. Second persuasive evidence for functional specialization in extrastriate cortex, and notably the discovery of cortical area V5/MT, suggested a separate region specialized for motion processing. Shortly thereafter the remarkable case of patient LM was published, providing compelling evidence for a selective and specific loss of movement vision. The case is reviewed here, along with an assessment of its contribution to visual neuroscience. PMID:25741251

Perception for mobile robot navigation: A survey of the state of the art

NASA Technical Reports Server (NTRS)

Kortenkamp, David

1994-01-01

In order for mobile robots to navigate safely in unmapped and dynamic environments they must perceive their environment and decide on actions based on those perceptions. There are many different sensing modalities that can be used for mobile robot perception; the two most popular are ultrasonic sonar sensors and vision sensors. This paper examines the state-of-the-art in sensory-based mobile robot navigation. The first issue in mobile robot navigation is safety. This paper summarizes several competing sonar-based obstacle avoidance techniques and compares them. Another issue in mobile robot navigation is determining the robot's position and orientation (sometimes called the robot's pose) in the environment. This paper examines several different classes of vision-based approaches to pose determination. One class of approaches uses detailed, a prior models of the robot's environment. Another class of approaches triangulates using fixed, artificial landmarks. A third class of approaches builds maps using natural landmarks. Example implementations from each of these three classes are described and compared. Finally, the paper presents a completely implemented mobile robot system that integrates sonar-based obstacle avoidance with vision-based pose determination to perform a simple task.

Effect of sports vision exercise on visual perception and reading performance in 7- to 10-year-old developmental dyslexic children.

PubMed

Badami, Rokhsareh; Mahmoudi, Sahar; Baluch, Bahman

2016-12-01

The presented study was aimed at identifying for the first time the influence of sports vision exercises on fundamental motor skills and cognitive skills of 7- to 10-year-old developmental dyslexic Persian children. A pretest-posttest quasi-experimental study was conducted. The statistical population of this study was 7- to 10-year-old dyslexic children referring to two centres of learning disorder in the city of Isfahan. Twenty two of these children were selected using available and purposive sampling from the statistical population and were randomly assigned into two groups of experimental and control. The former (experimental group) participated in sports vision exercise courses for 12 weeks (3 one hr sessions per week) and the latter (control group) continued their routine daily activities during the exercise. Before the beginning and at the end of the exercise, Gardner's test of visual perception test - revised and Dehkhoda's reading skills test was administered to both groups. The results showed that the sports vision exercises increases motor skills, visual perceptual skills and reading skills in developmental dyslexic children. Based on the results of the presented study it was concluded that sports vision exercises can be used for fundamental and cognitive skills of developmental dyslexic children.

Practitioners' Perception of the Impact of the Vision of Policy-Makers on Practice: The Example of the Recommendations of the Moser Commission

ERIC Educational Resources Information Center

Ade-Ojo, Gordon O.

2011-01-01

This paper presents the perception of practitioners of the impact of the Moser Committee recommendations and the Skills for Life agenda it generated. The paper further explores areas of convergence and divergence between practitioners' perceptions and the underpinning values of the Moser Committee recommendations. The study utilised a range of…

Teledetection passive et processus decisionnel a reference spatiale: Application a l'aquaculture en milieu marin

NASA Astrophysics Data System (ADS)

Habbane, Mohamed

L'objectif de cette etude est d'elaborer un processus decisionnel a reference spatiale (PDRS) pour la mariculture. Le PDRS est applique aux eaux cotieres de la baie des Chaleurs, dans le golfe du Saint-Laurent (Canada). Une carte preliminaire regionale d'indices du potentiel maricole, d'une limite de resolution spatiale de 1 kmsp2, est produite avec des parametres du niveau 1. Ces parametres englobent la temperature de l'eau de surface, extraite des images AVHRR, la salinite, les courants ainsi que les pigments chlorophylliens, quantifies a l'aide de mesures in situ. Les images AVHRR, prises en 1994, ont ete utiliees comme reference primaire pour selectionner des aires pouvant supporter une activite maricole sur la cote nord de la baie des Chaleurs. La temperature de surface extraite de ces images permet une analyse mesoechelle a la fois qualitative et quantitative des processus cotiers observes pendant la periode d'acquisition des donnees. Les autres donnees, soit la salinite, les courants et les concentrations en pigments chlorophylliens, sont analysees de facon a identifier la variabilite spatio-temporelle des caracteristiques des eaux de surface. L'ensemble des informations permet de produire une carte preliminaire regionale d'indices du potentiel maricole de la partie centrale de la baie des Chaleurs. Selon cet indice (defini entre 0 et 1), le secteur de potentiel aquicole de 0,5 a 0,75 s'etend sur une superficie d'environ 300 kmsp2. La localisation de cette aire potentielle est en accord avec les fortes concentrations en pigments chlrophylliens, presentant des conditions environnementales ideales a une haute productivite biologique. Par la suite la carte preliminaire est modifiee en tenant compte des parametres du niveau 2. Ces parametres sont la geomorphologie littorale, la bathymetrie, les sediments en suspension, les vents, les vagues, le debit d'eau douce, la glace marine, le carbone organique dissous, les aires de peche et les sources de pollution. Ces parametres sont compares deux a deux par rapport a la carte preliminaire regionale d'indices du potentiel maricole pour determiner leur poids relatif. La carte finale produite avec ces parametres du niveau 2 presente un secteur ou les indices du potentiel maricole sont de 0,5 a 0,75. Ce secteur longe la cote et epouse les isobathes de 10 a 30 m de profondeur. L'effet de la profondeur d'eau semble avoir jouer un role important. Le secteur de potentiel maricole de 0,25 a 0,5 est toujours present et couvre une superficie d'environ 426 kmsp2. L'etude necessitera toujours un suivi des conditions environnementales prevalant dans la region. Ce suivi peut etre effectue a l'aide d'un outil de vision aerospatiale (capteurs de teledetection) et d'analyse spatio-temporelle (SIG-PDRS). (Abstract shortened by UMI.)

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

PubMed

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.

Perceptual organization in computer vision - A review and a proposal for a classificatory structure

NASA Technical Reports Server (NTRS)

Sarkar, Sudeep; Boyer, Kim L.

1993-01-01

The evolution of perceptual organization in biological vision, and its necessity in advanced computer vision systems, arises from the characteristic that perception, the extraction of meaning from sensory input, is an intelligent process. This is particularly so for high order organisms and, analogically, for more sophisticated computational models. The role of perceptual organization in computer vision systems is explored. This is done from four vantage points. First, a brief history of perceptual organization research in both humans and computer vision is offered. Next, a classificatory structure in which to cast perceptual organization research to clarify both the nomenclature and the relationships among the many contributions is proposed. Thirdly, the perceptual organization work in computer vision in the context of this classificatory structure is reviewed. Finally, the array of computational techniques applied to perceptual organization problems in computer vision is surveyed.

Objective evaluation of chemotherapy-induced peripheral neuropathy using quantitative pain measurement system (Pain Vision®), a pilot study.

PubMed

Sato, Junya; Mori, Megumi; Nihei, Satoru; Takeuchi, Satoshi; Kashiwaba, Masahiro; Kudo, Kenzo

2017-01-01

In an evaluation of chemotherapy-induced peripheral neuropathy (CIPN), objectivity may be poor because the evaluation is determined by the patient's subjective assessment. In such cases, management of neuropathy may be delayed and CIPN symptoms may become severe. In this pilot study, we attempted an objective evaluation of CIPN using a quantitative pain measurement system (Pain Vision ® ). The subjects were patients with gynecologic cancer who underwent chemotherapy using taxane and platinum drugs. The grade of the peripheral sensory nerve disorder was based on the Common Terminology Criteria for Adverse Events (CTC-AE) ver. 4.0 and was evaluated before the initiation of therapy and up to six chemotherapy cycles. A symptom scale assessed by the patients using a peripheral neuropathy questionnaire (PNQ) was also evaluated. Simultaneously during these evaluations, graded electric current was applied from the probe to a fingertip and measured both the lowest perceptible current and lowest current perceived as pain by Pain Vision ® . From these values, the pain degree was calculated from the following formula: (pain perception current value - lowest perceptible current value) ÷ lowest perceptible current value × 100. We compared the pain degrees by Pain Vision ® during CIPN development with the value obtained before chemotherapy initiation. Forty-one patients were enrolled. In the evaluation by a medical professional, 28 (64.3%) patients developed CIPN during 2.5 ± 1.1 chemotherapy cycles (mean ± standard deviation). The pain degree by Pain Vision ® at grade 1 and 2 CIPN development according to the evaluation (CTC-AE) was significantly decreased compared to that before chemotherapy initiation (126.0 ± 114.5 vs. 69.8 ± 46.8, p  = 0.001, and 126.0 ± 114.5 vs. 32.8 ± 32.6, p  = 0.004). Changes in the pain degree by Pain Vision ® were also found during scale B and C, D CIPN development in the patient evaluation (PNQ) (115.9 ± 112.4 vs. 70.6 ± 56.5, p  = 0.005, and 115.9 ± 112.4 vs. 46.3 ± 42.9, p  = 0.004). In the 13 patients in whom CIPN did not occur, no significant decrease in the pain degree by Pain Vision ® was detected ( p  = 0.764). There was no discontinuation of the measurements because of adverse events such as discomfort from the electric current. The decrease in the pain degree measured by Pain Vision ® was associated with the onset of CIPN symptoms. Particularly, detection of CIPN by Pain Vision ® was possible, though most of the CIPN that occurred was low grade or mild symptom. Pain Vision ® might become a noninvasive and convenient objective CIPN detection tool to supplement subjective CIPN evaluation. The study approval number in the institution; H25-140. Registered December 17, 2013.

Educational Applications of Vision Therapy: A Pilot Study on Children with Autism.

ERIC Educational Resources Information Center

Lovelace, Kelly; Rhodes, Heidi; Chambliss, Catherine

This report discusses the outcomes of a study that explored the feasibility of using vision therapy (VT) as part of an interdisciplinary approach to the education of children with autism. Traditional research on VT has explored its usefulness in helping patients to use both eyes together, improve depth perception, and enhance visual acuity.…

Vision in Children and Adolescents with Autistic Spectrum Disorder: Evidence for Reduced Convergence

ERIC Educational Resources Information Center

Milne, Elizabeth; Griffiths, Helen; Buckley, David; Scope, Alison

2009-01-01

Evidence of atypical perception in individuals with ASD is mainly based on self report, parental questionnaires or psychophysical/cognitive paradigms. There have been relatively few attempts to establish whether binocular vision is enhanced, intact or abnormal in those with ASD. To address this, we screened visual function in 51 individuals with…

A "Vision and Change" Reform of Introductory Biology Shifts Faculty Perceptions and Use of Active Learning

ERIC Educational Resources Information Center

Auerbach, Anna Jo; Schussler, Elisabeth

2017-01-01

Increasing faculty use of active-learning (AL) pedagogies in college classrooms is a persistent challenge in biology education. A large research-intensive university implemented changes to its biology majors' two-course introductory sequence as outlined by the "Vision and Change in Undergraduate Biology Education" final report. One goal…

Initial Efforts to Coordinate Appreciative Inquiry: Facilitators' Experiences and Perceptions

ERIC Educational Resources Information Center

Breslow, Ken; Crowell, Lyn; Francis, Lee; Gordon, Stephen P.

2015-01-01

Appreciative inquiry (AI) is an alternative approach to action research that moves participants beyond problem solving and builds on existing strengths as the participants co-construct a positive vision of the future and move toward that vision through collaborative inquiry. Ph.D. students enrolled in a doctoral seminar on AI (who also are…

The Impact of Visual Impairment on Perceived School Climate

ERIC Educational Resources Information Center

Schade, Benjamin; Larwin, Karen H.

2015-01-01

The current investigation examines whether visual impairment has an impact on a student's perception of the school climate. Using a large national sample of high school students, perceptions were examined for students with vision impairment relative to students with no visual impairments. Three factors were examined: self-reported level of…

Influence of Target Population Misspecification on Employee Perceptions at a Government Facility

ERIC Educational Resources Information Center

Smith, Joe Lee

2014-01-01

Numerous researchers have conducted qualitative and quantitative studies examining employee perceptions related to changes in their work environment based upon management/top-down (deductive) communication of vision, mission, and envisioned organization goals (Hofstede, Neuijen, Daval, Ohayv, & Sanders 1990), but research on the influence of…

78 FR 67454 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-12

... his right eye is 20/20, and in his left eye, no light perception. Following an examination in 2013... perception. Following an examination in 2013, his optometrist noted, ``His visual condition is stable and he... small risk of progression, and the added safety concern with commercial vehicle operation.'' Mr. Granby...

Focal damage to macaque photoreceptors produces persistent visual loss

PubMed Central

Strazzeri, Jennifer M.; Hunter, Jennifer J.; Masella, Benjamin D.; Yin, Lu; Fischer, William S.; DiLoreto, David A.; Libby, Richard T.; Williams, David R.; Merigan, William H.

2014-01-01

Insertion of light-gated channels into inner retina neurons restores neural light responses, light evoked potentials, visual optomotor responses and visually-guided maze behavior in mice blinded by retinal degeneration. This method of vision restoration bypasses damaged outer retina, providing stimulation directly to retinal ganglion cells in inner retina. The approach is similar to that of electronic visual protheses, but may offer some advantages, such as avoidance of complex surgery and direct targeting of many thousands of neurons. However, the promise of this technique for restoring human vision remains uncertain because rodent animal models, in which it has been largely developed, are not ideal for evaluating visual perception. On the other hand, psychophysical vision studies in macaque can be used to evaluate different approaches to vision restoration in humans. Furthermore, it has not been possible to test vision restoration in macaques, the optimal model for human-like vision, because there has been no macaque model of outer retina degeneration. In this study, we describe development of a macaque model of photoreceptor degeneration that can in future studies be used to test restoration of perception by visual prostheses. Our results show that perceptual deficits caused by focal light damage are restricted to locations at which photoreceptors are damaged, that optical coherence tomography (OCT) can be used to track such lesions, and that adaptive optics retinal imaging, which we recently used for in vivo recording of ganglion cell function, can be used in future studies to examine these lesions. PMID:24316158

Distance Estimation to Flashes in a Simulated Night Vision Environment

DTIC Science & Technology

2007-12-01

indirect perception, which has influenced theorists since, is Hermann von Helmholtz’s theory of unconscious conclusions or unconscious inference [6...Goldstein et al. (Eds.), Blackwell handbook of perception (pp. 53-91). Malden, MA: Blackwell Publishers. [6] Helmholtz, H. von (1867/1925). Treatise on...physiological optics (from 3rd German edition, Vol. III). New York: Dover Publications. [7] Helmholtz, H. von (1878/1968). The facts of perception. In

Bush v. Bin Laden: Effect of State Emotion on Perceived Threat is Mediated by Emotion Towards the Threat Agent (Bush vs. Ben Laden: l’Effet de l’Emotion etat sur la Menace Percue est Mediatisees par l’Emotion vis-a-vis de l’Agent Menacant)

DTIC Science & Technology

2009-07-01

auteurs discu- tent des implications des resultats pour les theories qui postulent un effet de I’emotion sur la perception du risque et pour com...effect of global negative emotion on perceived threat . The authors discuss implications of the findings for theories that postulate an effect of... auteurs ont mene une etude perception j emotion j experimentale afin d’examiner les effets d’etats emotionnels Specifi- ques (peur et colere) et globaux

Multistability, cross-modal binding and the additivity of conjoined grouping principles

PubMed Central

Kubovy, Michael; Yu, Minhong

2012-01-01

We present a sceptical view of multimodal multistability—drawing most of our examples from the relation between audition and vision. We begin by summarizing some of the principal ways in which audio-visual binding takes place. We review the evidence that unambiguous stimulation in one modality may affect the perception of a multistable stimulus in another modality. Cross-modal influences of one multistable stimulus on the multistability of another are different: they have occurred only in speech perception. We then argue that the strongest relation between perceptual organization in vision and perceptual organization in audition is likely to be by way of analogous Gestalt laws. We conclude with some general observations about multimodality. PMID:22371617

A sensory origin for color-word stroop effects in aging: simulating age-related changes in color-vision mimics age-related changes in Stroop.

PubMed

Ben-David, Boaz M; Schneider, Bruce A

2010-11-01

An increase in Stroop effects with age can be interpreted as reflecting age-related reductions in selective attention, cognitive slowing, or color-vision. In the present study, 88 younger adults performed a Stroop test with two color-sets, saturated and desaturated, to simulate an age-related decrease in color perception. This color manipulation with younger adults was sufficient to lead to an increase in Stroop effects that mimics age-effects. We conclude that age-related changes in color perception can contribute to the differences in Stroop effects observed in aging. Finally, we suggest that the clinical applications of Stroop take this factor into account.

Attention and multisensory modulation argue against total encapsulation.

PubMed

de Haas, Benjamin; Schwarzkopf, Dietrich Samuel; Rees, Geraint

2016-01-01

Firestone & Scholl (F&S) postulate that vision proceeds without any direct interference from cognition. We argue that this view is extreme and not in line with the available evidence. Specifically, we discuss two well-established counterexamples: Attention directly affects core aspects of visual processing, and multisensory modulations of vision originate on multiple levels, some of which are unlikely to fall "within perception."

Leadership Advisory Boards in Texas: Their Perceived Ability and Utilization as the Visioning Body for Program Development

ERIC Educational Resources Information Center

Ripley, Jeff P.; Cummings, Scott R.; Lockett, Landry L.

2012-01-01

The ability of Leadership Advisory Boards within Texas AgriLife Extension Service to function as the primary visioning/needs assessment source is paramount to maintaining the grassroots connection for programs. The study reported here sought to measure the self-perceptions of members' ability to meet the demand associated with this role. The study…

Perceptions of Leadership Effectiveness in Schools for Children Who Are Blind or Have Low Vision in Nigeria

ERIC Educational Resources Information Center

Oyinlade, A. Olu; Ajuwon, Paul M.

2017-01-01

This study used the standard-based essential behavioural leadership qualities (EBLQ) method of leadership assessment, to determine leadership effectiveness of the principals of the schools for children who are blind and have low vision in Nigeria, from the perspective of the teachers of these schools. The four-stage method of leadership assessment…

76 FR 29022 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-19

... due to a traumatic injury sustained in 1982. The visual acuity in his right eye is 20/20 and in his.... Newman Mr. Newman, 50, has no light perception in his left eye due to a traumatic injury that occurred... in a CMV. Eric C. Esplin Mr. Esplin, 46, has loss of vision in his right eye due to a traumatic...

How the venetian blind percept emerges from the laminar cortical dynamics of 3D vision

PubMed Central

Cao, Yongqiang; Grossberg, Stephen

2014-01-01

The 3D LAMINART model of 3D vision and figure-ground perception is used to explain and simulate a key example of the Venetian blind effect and to show how it is related to other well-known perceptual phenomena such as Panum's limiting case. The model proposes how lateral geniculate nucleus (LGN) and hierarchically organized laminar circuits in cortical areas V1, V2, and V4 interact to control processes of 3D boundary formation and surface filling-in that simulate many properties of 3D vision percepts, notably consciously seen surface percepts, which are predicted to arise when filled-in surface representations are integrated into surface-shroud resonances between visual and parietal cortex. Interactions between layers 4, 3B, and 2/3 in V1 and V2 carry out stereopsis and 3D boundary formation. Both binocular and monocular information combine to form 3D boundary and surface representations. Surface contour surface-to-boundary feedback from V2 thin stripes to V2 pale stripes combines computationally complementary boundary and surface formation properties, leading to a single consistent percept, while also eliminating redundant 3D boundaries, and triggering figure-ground perception. False binocular boundary matches are eliminated by Gestalt grouping properties during boundary formation. In particular, a disparity filter, which helps to solve the Correspondence Problem by eliminating false matches, is predicted to be realized as part of the boundary grouping process in layer 2/3 of cortical area V2. The model has been used to simulate the consciously seen 3D surface percepts in 18 psychophysical experiments. These percepts include the Venetian blind effect, Panum's limiting case, contrast variations of dichoptic masking and the correspondence problem, the effect of interocular contrast differences on stereoacuity, stereopsis with polarity-reversed stereograms, da Vinci stereopsis, and perceptual closure. These model mechanisms have also simulated properties of 3D neon color spreading, binocular rivalry, 3D Necker cube, and many examples of 3D figure-ground separation. PMID:25309467

How the venetian blind percept emerges from the laminar cortical dynamics of 3D vision.

PubMed

Cao, Yongqiang; Grossberg, Stephen

2014-01-01

The 3D LAMINART model of 3D vision and figure-ground perception is used to explain and simulate a key example of the Venetian blind effect and to show how it is related to other well-known perceptual phenomena such as Panum's limiting case. The model proposes how lateral geniculate nucleus (LGN) and hierarchically organized laminar circuits in cortical areas V1, V2, and V4 interact to control processes of 3D boundary formation and surface filling-in that simulate many properties of 3D vision percepts, notably consciously seen surface percepts, which are predicted to arise when filled-in surface representations are integrated into surface-shroud resonances between visual and parietal cortex. Interactions between layers 4, 3B, and 2/3 in V1 and V2 carry out stereopsis and 3D boundary formation. Both binocular and monocular information combine to form 3D boundary and surface representations. Surface contour surface-to-boundary feedback from V2 thin stripes to V2 pale stripes combines computationally complementary boundary and surface formation properties, leading to a single consistent percept, while also eliminating redundant 3D boundaries, and triggering figure-ground perception. False binocular boundary matches are eliminated by Gestalt grouping properties during boundary formation. In particular, a disparity filter, which helps to solve the Correspondence Problem by eliminating false matches, is predicted to be realized as part of the boundary grouping process in layer 2/3 of cortical area V2. The model has been used to simulate the consciously seen 3D surface percepts in 18 psychophysical experiments. These percepts include the Venetian blind effect, Panum's limiting case, contrast variations of dichoptic masking and the correspondence problem, the effect of interocular contrast differences on stereoacuity, stereopsis with polarity-reversed stereograms, da Vinci stereopsis, and perceptual closure. These model mechanisms have also simulated properties of 3D neon color spreading, binocular rivalry, 3D Necker cube, and many examples of 3D figure-ground separation.

ShipMo3D Version 3.0 User Manual for Computing Ship Motions in the Time and Frequency Domains

DTIC Science & Technology

2012-01-01

permettent de modéliser un navire en manœuvre libre et en eau calme ou dans les vagues. SM3DBuildSeaway construit des modèles de voie maritime à trajet...manœuvrant libre - ment en eau calme ou dans une voie maritime modélisée. Plusieurs applications du logiciel ShipMo3D font des prévisions des mouvements de...can be produced. For a random seaway, the range of wave frequencies should be sufficient to encompass almost all energy within the wave spectrum. For

The Impact of a Sports Vision Training Program in Youth Field Hockey Players

PubMed Central

Schwab, Sebastian; Memmert, Daniel

2012-01-01

The aim of this study was to investigate whether a sports vision training program improves the visual performance of youth male field hockey players, ages 12 to 16 years, after an intervention of six weeks compared to a control group with no specific sports vision training. The choice reaction time task at the D2 board (Learning Task I), the functional field of view task (Learning Task II) and the multiple object tracking (MOT) task (Transfer Task) were assessed before and after the intervention and again six weeks after the second test. Analyzes showed significant differences between the two groups for the choice reaction time task at the D2 board and the functional field of view task, with significant improvements for the intervention group and none for the control group. For the transfer task, we could not find statistically significant improvements for either group. The results of this study are discussed in terms of theoretical and practical implications. Key pointsPerceptual training with youth field hockey playersCan a sports vision training program improve the visual performance of youth male field hockey players, ages 12 to 16 years, after an intervention of six weeks compared to a control group with no specific sports vision training?The intervention was performed in the “VisuLab” as DynamicEye® SportsVision Training at the German Sport University Cologne.We ran a series of 3 two-factor univariate analysis of variance (ANOVA) with repeated measures on both within subject independent variables (group; measuring point) to examine the effects on central perception, peripheral perception and choice reaction time.The present study shows an improvement of certain visual abilities with the help of the sports vision training program. PMID:24150071

The effect of vision and hearing loss on listeners' perception of referential meaning in music.

PubMed

Darrow, Alice-Ann; Novak, Julie

2007-01-01

The purpose of the present study was to examine the effect of vision and hearing loss on listeners' perception of referential meaning in music. Participants were students at a state school for the deaf and blind, and students with typical hearing and vision who attended neighboring public schools (N = 96). The music stimuli consisted of six 37-second randomly ordered excerpts from Saint Saëns, Carnival of the Animals. The excerpts were chosen because of their use in similar studies and the composer's clearly intended meaning conveyed in the titles of the excerpts. After allowing for appropriate procedural accommodations for participants with hearing or vision loss, all participants were asked to select the image portrayed by the music. A univariate ANOVA was computed to address the research question, "Do students with vision or hearing loss assign the same visual images to music as students without such sensory losses?" Data were analyzed to examine the effects of sensory condition as well as age and gender. A significant main effect was found for sensory condition, with follow up tests indicating that participants with typical hearing and vision agreed with the composer's intended meaning significantly more often than did participants with vision or hearing loss. No significant main effects were found for gender or age, and no significant interactions were found. Summary data indicated that selected images were more easily identified, or were more difficult to identify across conditions. The data also revealed an order of difficulty and patterns of confusion that were similar across sensory conditions and ages, indicating participant responses were not random, and that some referential meaning in music is conventional.

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

PubMed

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.

Cirque du Monde en tant qu’intervention en santé

PubMed Central

Fournier, Cynthia; Drouin, Mélodie-Anne; Marcoux, Jérémie; Garel, Patricia; Bochud, Emmanuel; Théberge, Julie; Aubertin, Patrice; Favreau, Gil; Fleet, Richard

2014-01-01

Résumé Objectif Présenter le programme Cirque du Monde du Cirque du Soleil et son potentiel en tant qu’intervention en soins de santé de première ligne pour les médecins de famille. Sources des données Une revue de la littérature menée dans les bases de données PubMed, Cochrane Library, PsycINFO, La Presse, Eureka, Google Scholar et Érudit à l’aide des mots-clés circus, social circus, Cirque du Monde et Cirque du Soleil. Une initiative à Montréal nommée Espace Transition qui s’inspire directement de Cirque du Monde. Communication personnelle avec le conseiller principal en formation en cirque social du Cirque du Soleil. Sélection d’études Les 50 premiers articles ou sites Internet répertoriés pour chaque mot-clé dans chacune des bases de données ciblées ont été révisés sur la base des titres et des résumés, s’il s’agissait d’un article, ou sur la base du titre et du contenu de la page, s’il s’agissait d’une page Internet. Ensuite, les articles et les sites Internet qui étudiaient un aspect du cirque social ou qui présentaient une intervention impliquant le cirque étaient retenus pour une révision. Aucune contrainte d’année de publication n’a été appliquée étant donné qu’on cherchait une littérature générale sur le cirque social. Synthèse Aucun article n’a été trouvé sur le cirque social en tant qu’intervention en santé. Nous avons trouvé une étude sur l’utilisation du cirque en tant qu’intervention en milieu scolaire. Cette étude a démontré une augmentation de l’estime personnelle des enfants grâce à l’intervention. Nous avons trouvé une étude sur l’utilisation du cirque en tant qu’intervention sur une réserve amérindienne. Cette étude présente des résultats qualitatifs non spécifiques au programme du cirque social. Les autres articles répertoriés n’étaient que des descriptions du cirque social. Un site web concernant l’utilisation du cirque social pour faciliter la réintégration sociale de jeunes traités en milieu hospitalier pour un trouble psychiatrique majeur a été répertorié. L’équipe du département de pédopsychiatrie du Centre hospitalier universitaire Sainte-Justine responsable de ce projet nommé Espace Transition a été contactée. Des résultats préliminaires non publiés du projet pilote montrent des améliorations significatives du fonctionnement général des patients. Selon le Cirque du Soleil, plusieurs projets de recherche portant sur l’impact thérapeutique du cirque social sont en cours à travers le monde. Conclusion Cirque du Monde rejoint une clientèle marginalisée difficilement accessible par le système de santé. Ce programme revêt un potentiel thérapeutique de par sa clientèle cible, sa promotion de saines habitudes de vie et le soutien qu’il offre par l’intermédiaire du groupe et des intervenants. Compte tenu des investissements financiers importants du Cirque du Soleil dans ce projet, le manque de littérature donnant accès à des données probantes constitue un enjeu important.

Memory colours affect colour appearance.

PubMed

Witzel, Christoph; Olkkonen, Maria; Gegenfurtner, Karl R

2016-01-01

Memory colour effects show that colour perception is affected by memory and prior knowledge and hence by cognition. None of Firestone & Scholl's (F&S's) potential pitfalls apply to our work on memory colours. We present a Bayesian model of colour appearance to illustrate that an interaction between perception and memory is plausible from the perspective of vision science.

Visions of Terror: A Q-Methodological Analysis of American Perceptions of International Terrorism.

ERIC Educational Resources Information Center

Dowling, Ralph E.; Nitcavic, Richard G.

A study examined the efficacy of Q-methodology as a tool to explain perceptions of the American public regarding international terrorism, seeking to identify through this methodology distinct views of terrorism and the significant variables characterizing those views. To develop their instrument, researchers interviewed 16 individuals and based…

Perception of Present and Vision of Future of Gifted Students

ERIC Educational Resources Information Center

Krneta, Docent Ljiljana

2016-01-01

Giftedness and talent are the focus of many professional and scientific debates. Starting from the phenomenological interpretation that emphasizes the perception of self and reflects the subjective experience of the present and the future, the author presents the attitude of the gifted and other students towards the psychological nature of…

78 FR 10251 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-13

..., please include a self-addressed, stamped envelope or postcard or print the acknowledgement page that... since 2003. The visual acuity in his right eye is no light perception, and in his left eye, 20/20... right eye is light perception, and in his left eye, 20/20. Following an examination in 2012, his...

Biomechanical versus Inertial Information: Stable Individual Differences in Perception of Self-Rotation

ERIC Educational Resources Information Center

Bruggeman, Hugo; Piuneu, Vadzim S.; Rieser, John J.; Pick, Herbert L., Jr.

2009-01-01

When turning without vision or audition, people tend to perceive their locomotion as a change in heading relative to objects in the remembered surroundings. Such perception of self-rotation depends on sensitivity to information for movement from biomechanical activity of the locomotor system or from inertial activation of the vestibular and…

Computational gestalts and perception thresholds.

PubMed

Desolneux, Agnès; Moisan, Lionel; Morel, Jean-Michel

2003-01-01

In 1923, Max Wertheimer proposed a research programme and method in visual perception. He conjectured the existence of a small set of geometric grouping laws governing the perceptual synthesis of phenomenal objects, or "gestalt" from the atomic retina input. In this paper, we review this set of geometric grouping laws, using the works of Metzger, Kanizsa and their schools. In continuation, we explain why the Gestalt theory research programme can be translated into a Computer Vision programme. This translation is not straightforward, since Gestalt theory never addressed two fundamental matters: image sampling and image information measurements. Using these advances, we shall show that gestalt grouping laws can be translated into quantitative laws allowing the automatic computation of gestalts in digital images. From the psychophysical viewpoint, a main issue is raised: the computer vision gestalt detection methods deliver predictable perception thresholds. Thus, we are set in a position where we can build artificial images and check whether some kind of agreement can be found between the computationally predicted thresholds and the psychophysical ones. We describe and discuss two preliminary sets of experiments, where we compared the gestalt detection performance of several subjects with the predictable detection curve. In our opinion, the results of this experimental comparison support the idea of a much more systematic interaction between computational predictions in Computer Vision and psychophysical experiments.

Optimizing the temporal dynamics of light to human perception.

PubMed

Rieiro, Hector; Martinez-Conde, Susana; Danielson, Andrew P; Pardo-Vazquez, Jose L; Srivastava, Nishit; Macknik, Stephen L

2012-11-27

No previous research has tuned the temporal characteristics of light-emitting devices to enhance brightness perception in human vision, despite the potential for significant power savings. The role of stimulus duration on perceived contrast is unclear, due to contradiction between the models proposed by Bloch and by Broca and Sulzer over 100 years ago. We propose that the discrepancy is accounted for by the observer's "inherent expertise bias," a type of experimental bias in which the observer's life-long experience with interpreting the sensory world overcomes perceptual ambiguities and biases experimental outcomes. By controlling for this and all other known biases, we show that perceived contrast peaks at durations of 50-100 ms, and we conclude that the Broca-Sulzer effect best describes human temporal vision. We also show that the plateau in perceived brightness with stimulus duration, described by Bloch's law, is a previously uncharacterized type of temporal brightness constancy that, like classical constancy effects, serves to enhance object recognition across varied lighting conditions in natural vision-although this is a constancy effect that normalizes perception across temporal modulation conditions. A practical outcome of this study is that tuning light-emitting devices to match the temporal dynamics of the human visual system's temporal response function will result in significant power savings.

Real-time tracking using stereo and motion: Visual perception for space robotics

NASA Technical Reports Server (NTRS)

Nishihara, H. Keith; Thomas, Hans; Huber, Eric; Reid, C. Ann

1994-01-01

The state-of-the-art in computing technology is rapidly attaining the performance necessary to implement many early vision algorithms at real-time rates. This new capability is helping to accelerate progress in vision research by improving our ability to evaluate the performance of algorithms in dynamic environments. In particular, we are becoming much more aware of the relative stability of various visual measurements in the presence of camera motion and system noise. This new processing speed is also allowing us to raise our sights toward accomplishing much higher-level processing tasks, such as figure-ground separation and active object tracking, in real-time. This paper describes a methodology for using early visual measurements to accomplish higher-level tasks; it then presents an overview of the high-speed accelerators developed at Teleos to support early visual measurements. The final section describes the successful deployment of a real-time vision system to provide visual perception for the Extravehicular Activity Helper/Retriever robotic system in tests aboard NASA's KC135 reduced gravity aircraft.

Disparity channels in early vision

PubMed Central

Roe, AW; Parker, AJ; Born, RT; DeAngelis, GC

2008-01-01

The last decade has seen a dramatic increase in our knowledge of the neural basis of stereopsis. New cortical areas have been found to represent binocular disparities, new representations of disparity information (e.g., relative disparity signals) have been uncovered, the first topographic maps of disparity have been measured, and the first causal links between neural activity and depth perception have been established. Equally exciting is the finding that training and experience affects how signals are channeled through different brain areas, a flexibility that may be crucial for learning, plasticity, and recovery of function. The collective efforts of several laboratories have established stereo vision as one of the most productive model systems for elucidating the neural basis of perception. Much remains to be learned about how the disparity signals that are initially encoded in primary visual cortex are routed to and processed by extrastriate areas to mediate the diverse capacities of 3D vision that enhance our daily experience of the world. PMID:17978018

Visual risk factors for falls in older people.

PubMed

Lord, Stephen R

2006-09-01

Poor vision reduces postural stability and significantly increases the risk of falls and fractures in older people. Most studies have found that poor visual acuity increases the risk of falls. However, studies that have included multiple visual measures have found that reduced contrast sensitivity and depth perception are the most important visual risk factors for falls. Multifocal glasses may add to this risk because their near-vision lenses impair distance contrast sensitivity and depth perception in the lower visual field. This reduces the ability of an older person to detect environmental hazards. There is now evidence that maximising vision through cataract surgery is an effective strategy for preventing falls. Further randomised controlled trials are required to determine whether individual strategies (such as restriction of use of multifocal glasses) or multi-strategy visual improvement interventions can significantly reduce falls in older people. Public health initiatives are required to raise awareness in older people and their carers of the importance of regular eye examinations and use of appropriate prescription glasses.

Relationship between upper extremity kinesthetic sense and writing performance by students with low vision.

PubMed

Aki, Esra; Atasavun, Songül; Kayihan, Holya

2008-06-01

Kinesthetic sense plays an important role in writing. Children with low vision lack sensory input from the environment given their loss of vision. This study assessed the effect of upper extremity kinesthetic sense on writing function in two groups, one of students with low vision (9 girls and 11 boys, 9.4 +/- 1.9 yr. of age) and one of sighted students (10 girls and 10 boys, 10.1 +/- 1.3 yr. of age). All participants were given the Kinesthesia Test and Jebsen Hand Function Test-Writing subtest. Students with low vision scored lower on kinesthetic perception and writing performance than sighted peers. The correlation between scores for writing performance and upper extremity kinesthetic sense in the two groups was significant (r = -.34). The probability of deficiencies in kinesthetic information in students with low vision must be remembered.

Relating Standardized Visual Perception Measures to Simulator Visual System Performance

NASA Technical Reports Server (NTRS)

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).

Antecedents of organizational engagement: exploring vision, mood and perceived organizational support with emotional intelligence as a moderator

PubMed Central

Mahon, Edward G.; Taylor, Scott N.; Boyatzis, Richard E.

2014-01-01

As organizational leaders worry about the appalling low percentage of people who feel engaged in their work, academics are trying to understand what causes an increase in engagement. We collected survey data from 231 team members from two organizations. We examined the impact of team members’ emotional intelligence (EI) and their perception of shared personal vision, shared positive mood, and perceived organizational support (POS) on the members’ degree of organizational engagement. We found shared vision, shared mood, and POS have a direct, positive association with engagement. In addition, shared vision and POS interact with EI to positively influence engagement. Besides highlighting the importance of shared personal vision, positive mood, and POS, our study contributes to the emergent understanding of EI by revealing EI’s amplifying effect on shared vision and POS in relation to engagement. We conclude by discussing the research and practical implications of this study. PMID:25477845

3D vision system assessment

NASA Astrophysics Data System (ADS)

Pezzaniti, J. Larry; Edmondson, Richard; Vaden, Justin; Hyatt, Bryan; Chenault, David B.; Kingston, David; Geulen, Vanilynmae; Newell, Scott; Pettijohn, Brad

2009-02-01

In this paper, we report on the development of a 3D vision system consisting of a flat panel stereoscopic display and auto-converging stereo camera and an assessment of the system's use for robotic driving, manipulation, and surveillance operations. The 3D vision system was integrated onto a Talon Robot and Operator Control Unit (OCU) such that direct comparisons of the performance of a number of test subjects using 2D and 3D vision systems were possible. A number of representative scenarios were developed to determine which tasks benefited most from the added depth perception and to understand when the 3D vision system hindered understanding of the scene. Two tests were conducted at Fort Leonard Wood, MO with noncommissioned officers ranked Staff Sergeant and Sergeant First Class. The scenarios; the test planning, approach and protocols; the data analysis; and the resulting performance assessment of the 3D vision system are reported.

Probabilistic Tracking and Trajectory Planning for Autonomous Ground Vehicles in Urban Environments

DTIC Science & Technology

2016-03-05

SECURITY CLASSIFICATION OF: The aim of this research is to develop a unified theory for perception and planning in autonomous ground vehicles, with a...Report Title The aim of this research is to develop a unified theory for perception and planning in autonomous ground vehicles, with a specific focus on...a combination of experimentally collected vision data and Monte- Carlo simulations. Smoothing for improved perception and robustness in planning

Pediatric and adult vision restoration after optic nerve sheath decompression for idiopathic intracranial hypertension.

PubMed

Bersani, Thomas A; Meeker, Austin R; Sismanis, Dimitrios N; Carruth, Bryant P

2016-06-01

To compare presentations of idiopathic intracranial hypertension and efficacy of optic nerve sheath decompression between adult and pediatric patients, a retrospective cohort study was completed All idiopathic intracranial hypertension patients undergoing optic nerve sheath decompression by one surgeon between 1991 and 2012 were included. Pre-operative and post-operative visual fields, visual acuity, color vision, and optic nerve appearance were compared between adult and pediatric (<18 years) populations. Outcome measures included percentage of patients with complications or requiring subsequent interventions. Thirty-one adults (46 eyes) and eleven pediatric patients (18 eyes) underwent optic nerve sheath decompression for vision loss from idiopathic intracranial hypertension. Mean deviation on visual field, visual acuity, color vision, and optic nerve appearance significantly improved across all subjects. Pre-operative mean deviation was significantly worse in children compared to adults (p=0.043); there was no difference in mean deviation post-operatively (p=0.838). Significantly more pediatric eyes (6) presented with light perception only or no light perception than adult eyes (0) (p=0.001). Pre-operative color vision performance in children (19%) was significantly worse than in adults (46%) (p=0.026). Percentage of patients with complications or requiring subsequent interventions did not differ between groups. The consistent improvement after surgery and low rate of complications suggest optic nerve sheath decompression is safe and effective in managing vision loss due to adult and pediatric idiopathic intracranial hypertension. Given the advanced pre-operative visual deficits seen in children, one might consider a higher index of suspicion in diagnosing, and earlier surgical intervention in treating pediatric idiopathic intracranial hypertension.

Elaboration de nouvelles approches micromecaniques pour l'optimisation des performances mecaniques des materiaux heterogenes

NASA Astrophysics Data System (ADS)

Aboutajeddine, Ahmed

Les modeles micromecaniques de transition d'echelles qui permettent de determiner les proprietes effectives des materiaux heterogenes a partir de la microstructure sont consideres dans ce travail. L'objectif est la prise en compte de la presence d'une interphase entre la matrice et le renforcement dans les modeles micromecaniques classiques, de meme que la reconsideration des approximations de base de ces modeles, afin de traiter les materiaux multiphasiques. Un nouveau modele micromecanique est alors propose pour tenir compte de la presence d'une interphase elastique mince lors de la determination des proprietes effectives. Ce modele a ete construit grace a l'apport de l'equation integrale, des operateurs interfaciaux de Hill et de la methode de Mori-Tanaka. Les expressions obtenues pour les modules globaux et les champs dans l'enrobage sont de nature analytique. L'approximation de base de ce modele est amelioree par la suite dans un nouveau modele qui s'interesse aux inclusions enrobees avec un enrobage mince ou epais. La resolution utilisee s'appuie sur une double homogeneisation realisee au niveau de l'inclusion enrobee et du materiau. Cette nouvelle demarche, permettra d'apprehender completement les implications des approximations de la modelisation. Les resultats obtenus sont exploites par la suite dans la solution de l'assemblage de Hashin. Ainsi, plusieurs modeles micromecaniques classiques d'origines differentes se voient unifier et rattacher, dans ce travail, a la representation geometrique de Hashin. En plus de pouvoir apprecier completement la pertinence de l'approximation de chaque modele dans cette vision unique, l'extension correcte de ces modeles aux materiaux multiphasiques est rendue possible. Plusieurs modeles analytiques et explicites sont alors proposee suivant des solutions de differents ordres de l'assemblage de Hashin. L'un des modeles explicite apparait comme une correction directe du modele de Mori-Tanaka, dans les cas ou celui ci echoue a donner de bons resultats. Finalement, ce modele de Mori-Tanaka corrige est utilise avec les operateurs de Hill pour construire un modele de transition d'echelle pour les materiaux ayant une interphase elastoplastique. La loi de comportement effective trouvee est de nature incrementale et elle est conjuguee a la relation de la plasticite de l'interphase. Des simulations d'essais mecaniques pour plusieurs proprietes de l'interphase plastique a permis de dresser des profils de l'enrobage octroyant un meilleur comportement au materiau.

Temporal dynamics of figure-ground segregation in human vision.

PubMed

Neri, Peter; Levi, Dennis M

2007-01-01

The segregation of figure from ground is arguably one of the most fundamental operations in human vision. Neural signals reflecting this operation appear in cortex as early as 50 ms and as late as 300 ms after presentation of a visual stimulus, but it is not known when these signals are used by the brain to construct the percepts of figure and ground. We used psychophysical reverse correlation to identify the temporal window for figure-ground signals in human perception and found it to lie within the range of 100-160 ms. Figure enhancement within this narrow temporal window was transient rather than sustained as may be expected from measurements in single neurons. These psychophysical results prompt and guide further electrophysiological studies.

Galileo perceptionist.

PubMed

Sinico, Michele

2012-01-01

The present paper focuses on Galileo's conception of perception. I take as my starting point the interpretation of the Galilean text by Piccolino and Wade (2008, Perception 37 1312-1340): Galileo's eye: a new vision of the senses in the work of Galileo Galilei. Three points are discussed: the criticism of naive realism, the theoretical role of perceptual laws, and the distinction between different qualities of experience. The conclusions support an alternative interpretation which underscores the crucial role of phenomenology of perception in Galileo's epistemology.

A spiking neural network model of 3D perception for event-based neuromorphic stereo vision systems

PubMed Central

Osswald, Marc; Ieng, Sio-Hoi; Benosman, Ryad; Indiveri, Giacomo

2017-01-01

Stereo vision is an important feature that enables machine vision systems to perceive their environment in 3D. While machine vision has spawned a variety of software algorithms to solve the stereo-correspondence problem, their implementation and integration in small, fast, and efficient hardware vision systems remains a difficult challenge. Recent advances made in neuromorphic engineering offer a possible solution to this problem, with the use of a new class of event-based vision sensors and neural processing devices inspired by the organizing principles of the brain. Here we propose a radically novel model that solves the stereo-correspondence problem with a spiking neural network that can be directly implemented with massively parallel, compact, low-latency and low-power neuromorphic engineering devices. We validate the model with experimental results, highlighting features that are in agreement with both computational neuroscience stereo vision theories and experimental findings. We demonstrate its features with a prototype neuromorphic hardware system and provide testable predictions on the role of spike-based representations and temporal dynamics in biological stereo vision processing systems. PMID:28079187

A spiking neural network model of 3D perception for event-based neuromorphic stereo vision systems.

PubMed

Osswald, Marc; Ieng, Sio-Hoi; Benosman, Ryad; Indiveri, Giacomo

2017-01-12

Stereo vision is an important feature that enables machine vision systems to perceive their environment in 3D. While machine vision has spawned a variety of software algorithms to solve the stereo-correspondence problem, their implementation and integration in small, fast, and efficient hardware vision systems remains a difficult challenge. Recent advances made in neuromorphic engineering offer a possible solution to this problem, with the use of a new class of event-based vision sensors and neural processing devices inspired by the organizing principles of the brain. Here we propose a radically novel model that solves the stereo-correspondence problem with a spiking neural network that can be directly implemented with massively parallel, compact, low-latency and low-power neuromorphic engineering devices. We validate the model with experimental results, highlighting features that are in agreement with both computational neuroscience stereo vision theories and experimental findings. We demonstrate its features with a prototype neuromorphic hardware system and provide testable predictions on the role of spike-based representations and temporal dynamics in biological stereo vision processing systems.

A spiking neural network model of 3D perception for event-based neuromorphic stereo vision systems

NASA Astrophysics Data System (ADS)

Osswald, Marc; Ieng, Sio-Hoi; Benosman, Ryad; Indiveri, Giacomo

2017-01-01

Stereo vision is an important feature that enables machine vision systems to perceive their environment in 3D. While machine vision has spawned a variety of software algorithms to solve the stereo-correspondence problem, their implementation and integration in small, fast, and efficient hardware vision systems remains a difficult challenge. Recent advances made in neuromorphic engineering offer a possible solution to this problem, with the use of a new class of event-based vision sensors and neural processing devices inspired by the organizing principles of the brain. Here we propose a radically novel model that solves the stereo-correspondence problem with a spiking neural network that can be directly implemented with massively parallel, compact, low-latency and low-power neuromorphic engineering devices. We validate the model with experimental results, highlighting features that are in agreement with both computational neuroscience stereo vision theories and experimental findings. We demonstrate its features with a prototype neuromorphic hardware system and provide testable predictions on the role of spike-based representations and temporal dynamics in biological stereo vision processing systems.

Channels of Vision and the Poetics of Drawing: Strategies for Teaching

ERIC Educational Resources Information Center

Riley, Howard

2014-01-01

This article introduces a novel approach to pedagogy within an art school in the UK HE sector, based upon a synthesis of perception theory and communication theory. It is argued that art students' drawing is empowered by strategies of teaching informed by aspects of James J. Gibson's ecological approach to visual perception relevant to an…

Seeing and Feeling for Self and Other: Proprioceptive Spatial Location Determines Multisensory Enhancement of Touch

ERIC Educational Resources Information Center

Cardini, Flavia; Haggard, Patrick; Ladavas, Elisabetta

2013-01-01

We have investigated the relation between visuo-tactile interactions and the self-other distinction. In the Visual Enhancement of Touch (VET) effect, non-informative vision of one's own hand improves tactile spatial perception. Previous studies suggested that looking at "another"person's hand could also enhance tactile perception, but did not…

Lightness modification of color image for protanopia and deuteranopia

NASA Astrophysics Data System (ADS)

Tanaka, Go; Suetake, Noriaki; Uchino, Eiji

2010-01-01

In multimedia content, colors play important roles in conveying visual information. However, color information cannot always be perceived uniformly by all people. People with a color vision deficiency, such as dichromacy, cannot recognize and distinguish certain color combinations. In this paper, an effective lightness modification method, which enables barrier-free color vision for people with dichromacy, especially protanopia or deuteranopia, while preserving the color information in the original image for people with standard color vision, is proposed. In the proposed method, an optimization problem concerning lightness components is first defined by considering color differences in an input image. Then a perceptible and comprehensible color image for both protanopes and viewers with no color vision deficiency or both deuteranopes and viewers with no color vision deficiency is obtained by solving the optimization problem. Through experiments, the effectiveness of the proposed method is illustrated.

Unconscious Imagination and the Mental Imagery Debate

PubMed Central

Brogaard, Berit; Gatzia, Dimitria Electra

2017-01-01

Traditionally, philosophers have appealed to the phenomenological similarity between visual experience and visual imagery to support the hypothesis that there is significant overlap between the perceptual and imaginative domains. The current evidence, however, is inconclusive: while evidence from transcranial brain stimulation seems to support this conclusion, neurophysiological evidence from brain lesion studies (e.g., from patients with brain lesions resulting in a loss of mental imagery but not a corresponding loss of perception and vice versa) indicates that there are functional and anatomical dissociations between mental imagery and perception. Assuming that the mental imagery and perception do not overlap, at least, to the extent traditionally assumed, then the question arises as to what exactly mental imagery is and whether it parallels perception by proceeding via several functionally distinct mechanisms. In this review, we argue that even though there may not be a shared mechanism underlying vision for perception and conscious imagery, there is an overlap between the mechanisms underlying vision for action and unconscious visual imagery. On the basis of these findings, we propose a modification of Kosslyn’s model of imagery that accommodates unconscious imagination and explore possible explanations of the quasi-pictorial phenomenology of conscious visual imagery in light of the fact that its underlying neural substrates and mechanisms typically are distinct from those of visual experience. PMID:28588527

Micro-calibration of space and motion by photoreceptors synchronized in parallel with cortical oscillations: A unified theory of visual perception.

PubMed

Jerath, Ravinder; Cearley, Shannon M; Barnes, Vernon A; Jensen, Mike

2018-01-01

A fundamental function of the visual system is detecting motion, yet visual perception is poorly understood. Current research has determined that the retina and ganglion cells elicit responses for motion detection; however, the underlying mechanism for this is incompletely understood. Previously we proposed that retinogeniculo-cortical oscillations and photoreceptors work in parallel to process vision. Here we propose that motion could also be processed within the retina, and not in the brain as current theory suggests. In this paper, we discuss: 1) internal neural space formation; 2) primary, secondary, and tertiary roles of vision; 3) gamma as the secondary role; and 4) synchronization and coherence. Movement within the external field is instantly detected by primary processing within the space formed by the retina, providing a unified view of the world from an internal point of view. Our new theory begins to answer questions about: 1) perception of space, erect images, and motion, 2) purpose of lateral inhibition, 3) speed of visual perception, and 4) how peripheral color vision occurs without a large population of cones located peripherally in the retina. We explain that strong oscillatory activity influences on brain activity and is necessary for: 1) visual processing, and 2) formation of the internal visuospatial area necessary for visual consciousness, which could allow rods to receive precise visual and visuospatial information, while retinal waves could link the lateral geniculate body with the cortex to form a neural space formed by membrane potential-based oscillations and photoreceptors. We propose that vision is tripartite, with three components that allow a person to make sense of the world, terming them "primary, secondary, and tertiary roles" of vision. Finally, we propose that Gamma waves that are higher in strength and volume allow communication among the retina, thalamus, and various areas of the cortex, and synchronization brings cortical faculties to the retina, while the thalamus is the link that couples the retina to the rest of the brain through activity by gamma oscillations. This novel theory lays groundwork for further research by providing a theoretical understanding that expands upon the functions of the retina, photoreceptors, and retinal plexus to include parallel processing needed to form the internal visual space that we perceive as the external world. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mining Videos for Features that Drive Attention

DTIC Science & Technology

2015-04-01

Psychology & Neuroscience Graduate Program, University of Southern California, 3641 Watt Way, HNB 10, Los Angeles, CA 90089, USA e-mail: itti@usc.edu...challenging question in neuroscience . Since the onset of visual experience, a human or animal begins to form a subjective percept which, depending on...been added based on neuroscience discoveries of mechanisms of vision in the brain as well as useful features based on computer vision. Figure14.1 illus

High-Level Vision: Top-Down Processing in Neurally Inspired Architectures

DTIC Science & Technology

2008-02-01

shunting subsystem). Visual input from the lateral geniculate enters the visual buffer via the black arrow at the bottom. Processing subsystems used... lateral geniculate nucleus of the thalamus (LGNd), the superior colliculus of the midbrain, and cortical regions V1 through V4. Beyond early vision...resonance imaging FOA: focus of attention IMPER: IMagery and PERception model IS: information shunting system LGNd: dorsal lateral geniculate nucleus

Human infrared vision is triggered by two-photon chromophore isomerization

PubMed Central

Palczewska, Grazyna; Vinberg, Frans; Stremplewski, Patrycjusz; Bircher, Martin P.; Salom, David; Komar, Katarzyna; Zhang, Jianye; Cascella, Michele; Wojtkowski, Maciej; Kefalov, Vladimir J.; Palczewski, Krzysztof

2014-01-01

Vision relies on photoactivation of visual pigments in rod and cone photoreceptor cells of the retina. The human eye structure and the absorption spectra of pigments limit our visual perception of light. Our visual perception is most responsive to stimulating light in the 400- to 720-nm (visible) range. First, we demonstrate by psychophysical experiments that humans can perceive infrared laser emission as visible light. Moreover, we show that mammalian photoreceptors can be directly activated by near infrared light with a sensitivity that paradoxically increases at wavelengths above 900 nm, and display quadratic dependence on laser power, indicating a nonlinear optical process. Biochemical experiments with rhodopsin, cone visual pigments, and a chromophore model compound 11-cis-retinyl-propylamine Schiff base demonstrate the direct isomerization of visual chromophore by a two-photon chromophore isomerization. Indeed, quantum mechanics modeling indicates the feasibility of this mechanism. Together, these findings clearly show that human visual perception of near infrared light occurs by two-photon isomerization of visual pigments. PMID:25453064

A Simple Principled Approach for Modeling and Understanding Uniform Color Metrics

PubMed Central

Smet, Kevin A.G.; Webster, Michael A.; Whitehead, Lorne A.

2016-01-01

An important goal in characterizing human color vision is to order color percepts in a way that captures their similarities and differences. This has resulted in the continuing evolution of “uniform color spaces,” in which the distances within the space represent the perceptual differences between the stimuli. While these metrics are now very successful in predicting how color percepts are scaled, they do so in largely empirical, ad hoc ways, with limited reference to actual mechanisms of color vision. In this article our aim is to instead begin with general and plausible assumptions about color coding, and then develop a model of color appearance that explicitly incorporates them. We show that many of the features of empirically-defined color order systems (such as those of Munsell, Pantone, NCS, and others) as well as many of the basic phenomena of color perception, emerge naturally from fairly simple principles of color information encoding in the visual system and how it can be optimized for the spectral characteristics of the environment. PMID:26974939

Some distinguishing characteristics of contour and texture phenomena in images

NASA Technical Reports Server (NTRS)

Jobson, Daniel J.

1992-01-01

The development of generalized contour/texture discrimination techniques is a central element necessary for machine vision recognition and interpretation of arbitrary images. Here, the visual perception of texture, selected studies of texture analysis in machine vision, and diverse small samples of contour and texture are all used to provide insights into the fundamental characteristics of contour and texture. From these, an experimental discrimination scheme is developed and tested on a battery of natural images. The visual perception of texture defined fine texture as a subclass which is interpreted as shading and is distinct from coarse figural similarity textures. Also, perception defined the smallest scale for contour/texture discrimination as eight to nine visual acuity units. Three contour/texture discrimination parameters were found to be moderately successful for this scale discrimination: (1) lightness change in a blurred version of the image, (2) change in lightness change in the original image, and (3) percent change in edge counts relative to local maximum.

'When is VISION asked too much'?

PubMed

van der Wildt, G J; den Brinker, B P; Wertheim, A H

1995-01-01

The last two decades a shift took place from substitutional/compensatory training to utilisation of residual vision regarding rehabilitation of the visually impaired. Some of the visually impaired are able to use their visual perception nearly as complete as normal seeing people in spite of a severe visual disability. On the other hand, people with nearly normal functions can be severely visually handicapped. To illustrate this, two cases are presented. The first case is a man, aged 47 years, with a juvenile macular degeneration on both eyes. In spite of a very low visual acuity of less then 0.05, he finished an university education and he is able to maintain himself very well in a leading position in a scientific environment, by using adequate low vision devices. Also for his leisure activities, as photography and speed skating, he relies upon visual perception. The second case is a woman, aged 30 years, with nearly normal visual functions, who is not able to read for longer periods caused by conflicting information from the body- and eye movements, and the visual input. This causes sickness during reading. She is unable to use books for her study and is working with recordings on tape. The results of a comprehensive visual assessment will be related to the specific low vision devices and its use.

Signatures of functional constraint at aye-aye opsin genes: the potential of adaptive color vision in a nocturnal primate.

PubMed

Perry, George H; Martin, Robert D; Verrelli, Brian C

2007-09-01

While color vision perception is thought to be adaptively correlated with foraging efficiency for diurnal mammals, those that forage exclusively at night may not need color vision nor have the capacity for it. Indeed, although the basic condition for mammals is dichromacy, diverse nocturnal mammals have only monochromatic vision, resulting from functional loss of the short-wavelength sensitive opsin gene. However, many nocturnal primates maintain intact two opsin genes and thus have dichromatic capacity. The evolutionary significance of this surprising observation has not yet been elucidated. We used a molecular population genetics approach to test evolutionary hypotheses for the two intact opsin genes of the fully nocturnal aye-aye (Daubentonia madagascariensis), a highly unusual and endangered Madagascar primate. No evidence of gene degradation in either opsin gene was observed for any of 8 aye-aye individuals examined. Furthermore, levels of nucleotide diversity for opsin gene functional sites were lower than those for 15 neutrally evolving intergenic regions (>25 kb in total), which is consistent with a history of purifying selection on aye-aye opsin genes. The most likely explanation for these findings is that dichromacy is advantageous for aye-ayes despite their nocturnal activity pattern. We speculate that dichromatic nocturnal primates may be able to perceive color while foraging under moonlight conditions, and suggest that behavioral and ecological comparisons among dichromatic and monochromatic nocturnal primates will help to elucidate the specific activities for which color vision perception is advantageous.

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

PubMed

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.

The genetics of normal and defective color vision

PubMed Central

Neitz, Jay; Neitz, Maureen

2011-01-01

The contributions of genetics research to the science of normal and defective color vision over the previous few decades are reviewed emphasizing the developments in the 25 years since the last anniversary issue of Vision Research. Understanding of the biology underlying color vision has been vaulted forward through the application of the tools of molecular genetics. For all their complexity, the biological processes responsible for color vision are more accessible than for many other neural systems. This is partly because of the wealth of genetic variations that affect color perception, both within and across species, and because components of the color vision system lend themselves to genetic manipulation. Mutations and rearrangements in the genes encoding the long, middle, and short wavelength sensitive cone pigments are responsible for color vision deficiencies and mutations have been identified that affect the number of cone types, the absorption spectrum of the pigments, the functionality and viability of the cones, and the topography of the cone mosaic. The addition of an opsin gene, as occurred in the evolution of primate color vision, and has been done in experimental animals can produce expanded color vision capacities and this has provided insight into the underlying neural circuitry. PMID:21167193

Ambiguities and conventions in the perception of visual art.

PubMed

Mamassian, Pascal

2008-09-01

Vision perception is ambiguous and visual arts play with these ambiguities. While perceptual ambiguities are resolved with prior constraints, artistic ambiguities are resolved by conventions. Is there a relationship between priors and conventions? This review surveys recent work related to these ambiguities in composition, spatial scale, illumination and color, three-dimensional layout, shape, and movement. While most conventions seem to have their roots in perceptual constraints, those conventions that differ from priors may help us appreciate how visual arts differ from everyday perception.

The Organization of Shape and Color in Vision and Art

PubMed Central

Pinna, Baingio

2011-01-01

The aim of this work is to study the phenomenal organization of shape and color in vision and art in terms of microgenesis of the object perception and creation. The idea of “microgenesis” is that the object perception and creation takes time to develop. Our hypothesis is that the roles of shape and color are extracted in sequential order and in the same order these roles are also used by artists to paint objects. Boundary contours are coded before color contours. The microgenesis of the object formation was demonstrated (i) by introducing new conditions derived from the watercolor illusion, where the juxtaposed contours are displaced horizontally or vertically, and based on variations of Matisse’s Woman, (ii) by studying descriptions and replications of visual objects in adults and children of different ages, and (iii) by analyzing the linguistic sequence and organization in a free naming task of the attributes related to shape and color. The results supported the idea of the microgenesis of the object perception, namely the temporal order in the formation of the roles of the object properties (shape before color). Some general principles were extracted from the experimental results. They can be a starting point to explore a new domain focused on the microgenesis of shape and color within the more general problem of object organization, where integrated and multidisciplinary studies based on art and vision science can be very useful. PMID:22065954

Early vision and focal attention

NASA Astrophysics Data System (ADS)

Julesz, Bela

1991-07-01

At the thirty-year anniversary of the introduction of the technique of computer-generated random-dot stereograms and random-dot cinematograms into psychology, the impact of the technique on brain research and on the study of artificial intelligence is reviewed. The main finding-that stereoscopic depth perception (stereopsis), motion perception, and preattentive texture discrimination are basically bottom-up processes, which occur without the help of the top-down processes of cognition and semantic memory-greatly simplifies the study of these processes of early vision and permits the linking of human perception with monkey neurophysiology. Particularly interesting are the unexpected findings that stereopsis (assumed to be local) is a global process, while texture discrimination (assumed to be a global process, governed by statistics) is local, based on some conspicuous local features (textons). It is shown that the top-down process of "shape (depth) from shading" does not affect stereopsis, and some of the models of machine vision are evaluated. The asymmetry effect of human texture discrimination is discussed, together with recent nonlinear spatial filter models and a novel extension of the texton theory that can cope with the asymmetry problem. This didactic review attempts to introduce the physicist to the field of psychobiology and its problems-including metascientific problems of brain research, problems of scientific creativity, the state of artificial intelligence research (including connectionist neural networks) aimed at modeling brain activity, and the fundamental role of focal attention in mental events.

Multiscale Enaction Model (MEM): the case of complexity and “context-sensitivity” in vision

PubMed Central

Laurent, Éric

2014-01-01

I review the data on human visual perception that reveal the critical role played by non-visual contextual factors influencing visual activity. The global perspective that progressively emerges reveals that vision is sensitive to multiple couplings with other systems whose nature and levels of abstraction in science are highly variable. Contrary to some views where vision is immersed in modular hard-wired modules, rather independent from higher-level or other non-cognitive processes, converging data gathered in this article suggest that visual perception can be theorized in the larger context of biological, physical, and social systems with which it is coupled, and through which it is enacted. Therefore, any attempt to model complexity and multiscale couplings, or to develop a complex synthesis in the fields of mind, brain, and behavior, shall involve a systematic empirical study of both connectedness between systems or subsystems, and the embodied, multiscale and flexible teleology of subsystems. The conceptual model (Multiscale Enaction Model [MEM]) that is introduced in this paper finally relates empirical evidence gathered from psychology to biocomputational data concerning the human brain. Both psychological and biocomputational descriptions of MEM are proposed in order to help fill in the gap between scales of scientific analysis and to provide an account for both the autopoiesis-driven search for information, and emerging perception. PMID:25566115

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

PubMed

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.

[Studies of vision by Leonardo da Vinci].

PubMed

Berggren, L

2001-01-01

Leonardo was an advocate of the intromission theory of vision. Light rays from the object to the eye caused visual perceptions which were transported to the brain ventricles via a hollow optic nerve. Leonardo introduced wax injections to explore the ventricular system. Perceptions were assumed to go to the "senso comune" in the middle (3rd) ventricle, also the seat of the soul. The processing station "imprensiva" in the anterior lateral horns together with memory "memoria" in th posterior (4th) ventricle integrated the visual perceptions to visual experience. - Leonardo's sketches with circular lenses in the center of the eye reveal that his dependence on medieval optics prevailed over anatomical observations. Drawings of the anatomy of the sectioned eye are missing although Leonardo had invented a new embedding technique. In order to dissect the eye without spilling its contents, the eye was first boiled in egg white and then cut. The procedure was now repeated and showed that the ovoid lens after boiling had become spherical. - Leonardo described that light rays were refracted and reflected in the eye but his imperfect anatomy prevented a development of physiological optics. He was, however, the first to compare the eye with a pin-hole camera (camera obscura). Leonardo's drawings of the inverted pictures on the back wall of a camera obscura inspired to its use as an instrument for artistic practice. The camera obscura was for centuries a model for explaining human vision.

Tunnel vision: sharper gradient of spatial attention in autism.

PubMed

Robertson, Caroline E; Kravitz, Dwight J; Freyberg, Jan; Baron-Cohen, Simon; Baker, Chris I

2013-04-17

Enhanced perception of detail has long been regarded a hallmark of autism spectrum conditions (ASC), but its origins are unknown. Normal sensitivity on all fundamental perceptual measures-visual acuity, contrast discrimination, and flicker detection-is strongly established in the literature. If individuals with ASC do not have superior low-level vision, how is perception of detail enhanced? We argue that this apparent paradox can be resolved by considering visual attention, which is known to enhance basic visual sensitivity, resulting in greater acuity and lower contrast thresholds. Here, we demonstrate that the focus of attention and concomitant enhancement of perception are sharper in human individuals with ASC than in matched controls. Using a simple visual acuity task embedded in a standard cueing paradigm, we mapped the spatial and temporal gradients of attentional enhancement by varying the distance and onset time of visual targets relative to an exogenous cue, which obligatorily captures attention. Individuals with ASC demonstrated a greater fall-off in performance with distance from the cue than controls, indicating a sharper spatial gradient of attention. Further, this sharpness was highly correlated with the severity of autistic symptoms in ASC, as well as autistic traits across both ASC and control groups. These findings establish the presence of a form of "tunnel vision" in ASC, with far-reaching implications for our understanding of the social and neurobiological aspects of autism.

Various Measures of the Effectiveness of Yellow Goggles

DTIC Science & Technology

1980-10-08

technique which is widely used r.o improve vision under these conditions is the use of yellow goggles. Skiers commonly don yellow goggles...different laboratory studies are presented. Two of the studies were of depth perception, since skiers believe that yellow goggles help them...selected for measurement because of practical considerations and theoretical implications. EXPERIMENTS ON DEPTH PERCEPTION Background Since skiers

Global Transsaccadic Change Blindness During Scene Perception

DTIC Science & Technology

2003-09-01

objects in natural scenes. Psychonomic Bulletin & Review , 8 , 761–768. Irwin, D.E. (1991). Information integration across saccadic eye... Psychonomic Bulletin & Review , 5 , 644–649. Tanaka, K. (1996). Inferotemporal cortex and object vision. Annual Review of Neuro- science... Bulletin & Review , 8 , 753–760. Hoffman, J.R., & Subramanian, B. (1995). The role of visual attention in saccadic eye movements. Perception

Self-powered vision electronic-skin basing on piezo-photodetecting Ppy/PVDF pixel-patterned matrix for mimicking vision.

PubMed

Han, Wuxiao; Zhang, Linlin; He, Haoxuan; Liu, Hongmin; Xing, Lili; Xue, Xinyu

2018-06-22

The development of multifunctional electronic-skin that establishes human-machine interfaces, enhances perception abilities or has other distinct biomedical applications is the key to the realization of artificial intelligence. In this paper, a new self-powered (battery-free) flexible vision electronic-skin has been realized from pixel-patterned matrix of piezo-photodetecting PVDF/Ppy film. The electronic-skin under applied deformation can actively output piezoelectric voltage, and the outputting signal can be significantly influenced by UV illumination. The piezoelectric output can act as both the photodetecting signal and electricity power. The reliability is demonstrated over 200 light on-off cycles. The sensing unit matrix of 6 × 6 pixels on the electronic-skin can realize image recognition through mapping multi-point UV stimuli. This self-powered vision electronic-skin that simply mimics human retina may have potential application in vision substitution.

Self-powered vision electronic-skin basing on piezo-photodetecting Ppy/PVDF pixel-patterned matrix for mimicking vision

NASA Astrophysics Data System (ADS)

Han, Wuxiao; Zhang, Linlin; He, Haoxuan; Liu, Hongmin; Xing, Lili; Xue, Xinyu

2018-06-01

The development of multifunctional electronic-skin that establishes human-machine interfaces, enhances perception abilities or has other distinct biomedical applications is the key to the realization of artificial intelligence. In this paper, a new self-powered (battery-free) flexible vision electronic-skin has been realized from pixel-patterned matrix of piezo-photodetecting PVDF/Ppy film. The electronic-skin under applied deformation can actively output piezoelectric voltage, and the outputting signal can be significantly influenced by UV illumination. The piezoelectric output can act as both the photodetecting signal and electricity power. The reliability is demonstrated over 200 light on–off cycles. The sensing unit matrix of 6 × 6 pixels on the electronic-skin can realize image recognition through mapping multi-point UV stimuli. This self-powered vision electronic-skin that simply mimics human retina may have potential application in vision substitution.

Evaluation of an organic light-emitting diode display for precise visual stimulation.

PubMed

Ito, Hiroyuki; Ogawa, Masaki; Sunaga, Shoji

2013-06-11

A new type of visual display for presentation of a visual stimulus with high quality was assessed. The characteristics of an organic light-emitting diode (OLED) display (Sony PVM-2541, 24.5 in.; Sony Corporation, Tokyo, Japan) were measured in detail from the viewpoint of its applicability to visual psychophysics. We found the new display to be superior to other display types in terms of spatial uniformity, color gamut, and contrast ratio. Changes in the intensity of luminance were sharper on the OLED display than those on a liquid crystal display. Therefore, such OLED displays could replace conventional cathode ray tube displays in vision research for high quality stimulus presentation. Benefits of using OLED displays in vision research were especially apparent in the fields of low-level vision, where precise control and description of the stimulus are needed, e.g., in mesopic or scotopic vision, color vision, and motion perception.

A note on image degradation, disability glare, and binocular vision

NASA Astrophysics Data System (ADS)

Rajaram, Vandana; Lakshminarayanan, Vasudevan

2013-08-01

Disability glare due to scattering of light causes a reduction in visual performance due to a luminous veil over the scene. This causes problem such as contrast detection. In this note, we report a study of the effect of this veiling luminance on human stereoscopic vision. We measured the effect of glare on the horopter measured using the apparent fronto-parallel plane (AFPP) criterion. The empirical longitudinal horopter measured using the AFPP criterion was analyzed using the so-called analytic plot. The analytic plot parameters were used for quantitative measurement of binocular vision. Image degradation plays a major effect on binocular vision as measured by the horopter. Under the conditions tested, it appears that if vision is sufficiently degraded then the addition of disability glare does not seem to significantly cause any further compromise in depth perception as measured by the horopter.

Acceptabilité du test VIH proposé aux nourrissons dans les services pédiatriques, en Côte d'Ivoire, Significations pour la couverture du diagnostic pédiatrique

PubMed Central

Oga, Maxime; Brou, Hermann; Dago-Akribi, Hortense; Coffie, Patrick; Amani-Bossé, Clarisse; Ékouévi, Didier; Yapo, Vincent; Menan, Hervé; Ndondoki, Camille; Timité-Konan, M.; Leroy, Valériane

2014-01-01

Résumé Problème: Le dépistage VIH chez les enfants a rarement été au centre des préoccupations des chercheurs. Quand le dépistage pédiatrique a retenu l'attention, cela a été pour éclairer seulement sur les performances diagnostiques en ignorant même que le test pédiatrique comme bien d'autres peut s'accepter ou se refuser. Cet article met au cœur de son analyse les raisons qui peuvent expliquer qu'on accepte ou qu'on refuse de faire dépister son enfant. Objectif: Etudier chez les parents, les mères, les facteurs explicatifs de l'acceptabilité du test VIH des nourrissons de moins de six mois. Méthodes: Entretien semi-directif à passages répétés avec les parents de nourrissons de moins de six mois dans les formations sanitaires pour la pesée/vaccination et les consultations pédiatriques avec proposition systématique d'un test VIH pour leur nourrisson. Résultats: Nous retenons que la réalisation effective du test pédiatrique du VIH chez le nourrisson repose sur trois éléments. Primo, le personnel de santé par son discours (qui dénote de ses connaissances et perceptions même sur l'infection) orienté vers les mères influence leur acceptation ou non du test. Secundo, la mère qui par ses connaissances et perceptions même sur le VIH, dont le statut particulier, l'impression de bien-être chez elle et son enfant influence toute réalisation du test pédiatrique VIH. Tertio, l'environnement conjugal de la mère, particulièrement caractérisé par les rapports au sein du couple, sur la facilité de parler du test VIH et sa réalisation chez les deux parents ou chez la mère seulement sont autant de facteurs qui influencent la réalisation effective du dépistage du VIH chez l'enfant. Le principe préventif du VIH, et le désir de faire tester l'enfant ne suffisent pas à eux seuls pour aboutir à sa réalisation effective, selon certaines mères confrontées au refus du conjoint. A l'opposé, les autres mères refusant la réalisation du test pédiatrique disent s'y opposer ; bien entendu, même dans le cas où le conjoint l'accepterait. Discussion: Les mères sont les principales mises en cause et craignent les réprimandes et la stigmatisation. Le père, le conjoint peut être un obstacle, quand il s'oppose au test VIH du nourrisson, ou devenir le facilitateur de sa réalisation s'il est convaincu. Le positionnement du père demeure donc essentiel dans la question de l'acceptabilité du VIH pédiatrique. Les mères en ont conscience et présagent des difficultés à faire dépister ou non les enfants sans avis préalable du conjoint à la fois père, et chef de famille. Conclusion: La question du dépistage pédiatrique du VIH, au terme de notre analyse, met en face trois éléments qui exigent une gestion globale pour assurer une couverture effective. Ces trois éléments n'existeraient pas sans s'influencer, donc ils sont constamment en interaction et empêchent ou favorisent la réalisation ou non du test pédiatrique. Aussi, dans une intention d'aboutir à une couverture effective du dépistage VIH des nourrissons, faut-il tenir compte d'une gestion harmonieuse de ces trois éléments: La première, la mère seule (avec ses connaissances, ses perceptions), son environnement conjugal (de proposition du test intégrant 1- l’époux et / ou père de l'enfant avec ses perceptions et connaissances sur l'infection 2- la facilité de parler du test et sa réalisation chez les deux ou un des parents, la mère) et les connaissances, attitudes et pratiques du personnel de l’établissement sanitaire sur l'infection du VIH. Recommandations: Nos recommandations proposent une redéfinition de l'approche du VIH/sida vers des familles exposées au VIH et une intégration plus accentuée du père facilitant leur propre acceptation du test VIH et celle de leur enfant. PMID:25088574

Pose Self-Calibration of Stereo Vision Systems for Autonomous Vehicle Applications.

PubMed

Musleh, Basam; Martín, David; Armingol, José María; de la Escalera, Arturo

2016-09-14

Nowadays, intelligent systems applied to vehicles have grown very rapidly; their goal is not only the improvement of safety, but also making autonomous driving possible. Many of these intelligent systems are based on making use of computer vision in order to know the environment and act accordingly. It is of great importance to be able to estimate the pose of the vision system because the measurement matching between the perception system (pixels) and the vehicle environment (meters) depends on the relative position between the perception system and the environment. A new method of camera pose estimation for stereo systems is presented in this paper, whose main contribution regarding the state of the art on the subject is the estimation of the pitch angle without being affected by the roll angle. The validation of the self-calibration method is accomplished by comparing it with relevant methods of camera pose estimation, where a synthetic sequence is used in order to measure the continuous error with a ground truth. This validation is enriched by the experimental results of the method in real traffic environments.

Pose Self-Calibration of Stereo Vision Systems for Autonomous Vehicle Applications

PubMed Central

Musleh, Basam; Martín, David; Armingol, José María; de la Escalera, Arturo

2016-01-01

Nowadays, intelligent systems applied to vehicles have grown very rapidly; their goal is not only the improvement of safety, but also making autonomous driving possible. Many of these intelligent systems are based on making use of computer vision in order to know the environment and act accordingly. It is of great importance to be able to estimate the pose of the vision system because the measurement matching between the perception system (pixels) and the vehicle environment (meters) depends on the relative position between the perception system and the environment. A new method of camera pose estimation for stereo systems is presented in this paper, whose main contribution regarding the state of the art on the subject is the estimation of the pitch angle without being affected by the roll angle. The validation of the self-calibration method is accomplished by comparing it with relevant methods of camera pose estimation, where a synthetic sequence is used in order to measure the continuous error with a ground truth. This validation is enriched by the experimental results of the method in real traffic environments. PMID:27649178

The Perception of Multiple Images

ERIC Educational Resources Information Center

Goldstein, E. Bruce

1975-01-01

A discussion of visual field, foveal and peripheral vision, eye fixations, recognition and recall of pictures, memory for meaning of pictures, and the relation between speed of presentation and memory. (Editor)

Advances in understanding the molecular basis of the first steps in color vision

PubMed Central

Hofmann, Lukas; Palczewski, Krzysztof

2015-01-01

Serving as one of our primary environmental inputs, vision is the most sophisticated sensory system in humans. Here, we present recent findings derived from energetics, genetics and physiology that provide a more advanced understanding of color perception in mammals. Energetics of cis–trans isomerization of 11-cis-retinal accounts for color perception in the narrow region of the electromagnetic spectrum and how human eyes can absorb light in the near infrared (IR) range. Structural homology models of visual pigments reveal complex interactions of the protein moieties with the light sensitive chromophore 11-cis-retinal and that certain color blinding mutations impair secondary structural elements of these G protein-coupled receptors (GPCRs). Finally, we identify unsolved critical aspects of color tuning that require future investigation. PMID:26187035

Night Vision Manual for the Flight Surgeon.

DTIC Science & Technology

1985-08-01

by optic nerve and pathways to Brodmann’s occipital areas 17 and 18). Perception occurs - vision Sensitive material ( retinal pigment) must be...clearly may be defined as glare. Glare becomes a problem in patients with opacities of the ocular media or with retinal diseases. 3 FME tN [I.I Sl IN FM...reduction of pupillary area caused by the drug. 3. Retinal causes of abnormal dark adaptation. a. Congenital stationary night blindness. b. etinitis

Chiari Malformation: Symptoms

MedlinePlus

... hands Fatigue Nausea Shortness of breath Blurred Vision Tinnitus Difficulty swallowing Leg weakness % 98 84 72 69 ... system) may not work properly, which may cause tinnitus (ringing in the ears), depth perception, running into ...

Randomized trial of the effect of contact lens wear on self-perception in children.

PubMed

Walline, Jeffrey J; Jones, Lisa A; Sinnott, Loraine; Chitkara, Monica; Coffey, Bradley; Jackson, John Mark; Manny, Ruth E; Rah, Marjorie J; Prinstein, Mitchell J

2009-03-01

To determine whether contact lens wear affects children's self-perceptions. The Adolescent and Child Health Initiative to Encourage Vision Empowerment Study was a randomized, single-masked trial conducted at five clinical centers in the United States. Subjects were 8- to 11-year-old myopic children randomly assigned to wear spectacles (n = 237) or soft contact lenses (n = 247) for 3 years. The primary endpoint was the Self-Perception Profile for Children Global Self-Worth scale. Secondary outcomes included the Physical Appearance, Athletic Competence, Scholastic Competence, Behavioral Conduct, and Social Acceptance Self-Perception Profile for Children scales. Global self-worth was not affected by contact lens wear [analysis of variance (ANOVA), difference = 0.06; 95% CI, -0.004 to 0.117]. Physical appearance (ANOVA, difference = 0.15; 95% CI, 0.07 to 0.22), athletic competence (ANOVA, difference = 0.08; 95% CI, 0.01 to 0.15), and social acceptance (ANOVA, difference = 0.10; 95% CI, 0.03 to 0.17) were all greater for contact lens wearers. Although contact lens wear does not affect global self-perceptions of 8- to 11-year-old myopic children their physical appearance, athletic competence, and social acceptance self-perceptions are likely to improve with contact lens wear. Eye care practitioners should consider the social and visual benefits of contact lens wear when choosing the most appropriate vision correction modality for children as young as 8 years of age.

Perceived overprotection: support gone bad?

PubMed

Cimarolli, Verena R; Reinhardt, Joann P; Horowitz, Amy

2006-01-01

This article focuses on the effects of perceived overprotection, a potentially problematic aspect of receiving support, on the ability to adjust to a chronic impairment, specifically, age-related vision loss. Perceived overprotection is an especially critical issue in this population of chronically ill older adults because of the safety issues associated with vision impairment and because perceptions on the part of the older adult that the support providers are overprotective may lead to excess disability. Participants were 584 older men and women with age-related vision impairment who applied for services at a vision rehabilitation agency. Path analysis was used to examine the effects of perceived overprotection on two positive indicators of adjustment: vision-specific adaptation and environmental mastery. Moreover, antecedents of perceived overprotection were examined. Higher levels of perceived overprotection were associated with less optimal adjustment to age-related vision loss, with lower scores on measures of vision-specific adaptation and environmental mastery. Higher levels of functional disability and instrumental support received were associated with higher levels of perceived overprotection. Findings indicate that support providers of older adults with visual impairment as well as vision rehabilitation service providers need to be aware of the detrimental impact of perceived overprotection.

When the Eyes Are Shut: The Strange Case of Girolamo Cardano's Idolum in Somniorum Synesiorum Libri IIII (1562).

PubMed

Corrias, Anna

2018-01-01

In his treatise on dreams Somniorum Synesiorum Libri IIII, published in 1562, the Italian Renaissance philosopher and physician Girolamo Cardano distinguishes between idola and visiones (or visa). Historians have discussed the reasons for such a distinction without taking into account Cardano's original theory of sense-perception. In this article I shall argue that, in order to interpret the meaning of idola and visiones in Cardano's theory of dreams, one should bear in mind his view that hearing is superior to sight and that while idola are essentially based on sound, visiones depend on images.

Memory for sound, with an ear toward hearing in complex auditory scenes.

PubMed

Snyder, Joel S; Gregg, Melissa K

2011-10-01

An area of research that has experienced recent growth is the study of memory during perception of simple and complex auditory scenes. These studies have provided important information about how well auditory objects are encoded in memory and how well listeners can notice changes in auditory scenes. These are significant developments because they present an opportunity to better understand how we hear in realistic situations, how higher-level aspects of hearing such as semantics and prior exposure affect perception, and the similarities and differences between auditory perception and perception in other modalities, such as vision and touch. The research also poses exciting challenges for behavioral and neural models of how auditory perception and memory work.

A TMS Study of the Ventral Projections from V1 with Implications for the Finding of Neural Correlates of Consciousness

ERIC Educational Resources Information Center

Overgaard, Morten; Nielsen, Jorgen Feldbaek; Fuglsang-Frederiksen, Anders

2004-01-01

The study of subliminal perception in normal and brain lesioned subjects has long been of interest to scholars studying the neural mechanisms behind conscious vision. Using brief durations and a developed methodology of introspective reporting, we present an experiment with visual stimuli that gives rise to little or no subliminal perception under…

Audibility and visual biasing in speech perception

NASA Astrophysics Data System (ADS)

Clement, Bart Richard

Although speech perception has been considered a predominantly auditory phenomenon, large benefits from vision in degraded acoustic conditions suggest integration of audition and vision. More direct evidence of this comes from studies of audiovisual disparity that demonstrate vision can bias and even dominate perception (McGurk & MacDonald, 1976). It has been observed that hearing-impaired listeners demonstrate more visual biasing than normally hearing listeners (Walden et al., 1990). It is argued here that stimulus audibility must be equated across groups before true differences can be established. In the present investigation, effects of visual biasing on perception were examined as audibility was degraded for 12 young normally hearing listeners. Biasing was determined by quantifying the degree to which listener identification functions for a single synthetic auditory /ba-da-ga/ continuum changed across two conditions: (1)an auditory-only listening condition; and (2)an auditory-visual condition in which every item of the continuum was synchronized with visual articulations of the consonant-vowel (CV) tokens /ba/ and /ga/, as spoken by each of two talkers. Audibility was altered by presenting the conditions in quiet and in noise at each of three signal-to- noise (S/N) ratios. For the visual-/ba/ context, large effects of audibility were found. As audibility decreased, visual biasing increased. A large talker effect also was found, with one talker eliciting more biasing than the other. An independent lipreading measure demonstrated that this talker was more visually intelligible than the other. For the visual-/ga/ context, audibility and talker effects were less robust, possibly obscured by strong listener effects, which were characterized by marked differences in perceptual processing patterns among participants. Some demonstrated substantial biasing whereas others demonstrated little, indicating a strong reliance on audition even in severely degraded acoustic conditions. Listener effects were not correlated with lipreading performance. The large effect of audibility suggests that conclusions regarding an increased reliance on vision among hearing- impaired listeners were premature, and that accurate comparisons only can be made after equating audibility. Further, if after such control, individual hearing- impaired listeners demonstrate the processing differences that were demonstrated in the present investigation, then these findings have the potential to impact aural rehabilitation strategies.

Predictors of vision impairment in Multiple Sclerosis.

PubMed

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.

The genetics of normal and defective color vision.

PubMed

Neitz, Jay; Neitz, Maureen

2011-04-13

The contributions of genetics research to the science of normal and defective color vision over the previous few decades are reviewed emphasizing the developments in the 25years since the last anniversary issue of Vision Research. Understanding of the biology underlying color vision has been vaulted forward through the application of the tools of molecular genetics. For all their complexity, the biological processes responsible for color vision are more accessible than for many other neural systems. This is partly because of the wealth of genetic variations that affect color perception, both within and across species, and because components of the color vision system lend themselves to genetic manipulation. Mutations and rearrangements in the genes encoding the long, middle, and short wavelength sensitive cone pigments are responsible for color vision deficiencies and mutations have been identified that affect the number of cone types, the absorption spectra of the pigments, the functionality and viability of the cones, and the topography of the cone mosaic. The addition of an opsin gene, as occurred in the evolution of primate color vision, and has been done in experimental animals can produce expanded color vision capacities and this has provided insight into the underlying neural circuitry. Copyright © 2010 Elsevier Ltd. All rights reserved.

The Impact of Early Visual Deprivation on Spatial Hearing: A Comparison between Totally and Partially Visually Deprived Children

PubMed Central

Cappagli, Giulia; Finocchietti, Sara; Cocchi, Elena; Gori, Monica

2017-01-01

The specific role of early visual deprivation on spatial hearing is still unclear, mainly due to the difficulty of comparing similar spatial skills at different ages and to the difficulty in recruiting young blind children from birth. In this study, the effects of early visual deprivation on the development of auditory spatial localization have been assessed in a group of seven 3–5 years old children with congenital blindness (n = 2; light perception or no perception of light) or low vision (n = 5; visual acuity range 1.1–1.7 LogMAR), with the main aim to understand if visual experience is fundamental to the development of specific spatial skills. Our study led to three main findings: firstly, totally blind children performed overall more poorly compared sighted and low vision children in all the spatial tasks performed; secondly, low vision children performed equally or better than sighted children in the same auditory spatial tasks; thirdly, higher residual levels of visual acuity are positively correlated with better spatial performance in the dynamic condition of the auditory localization task indicating that the more residual vision the better spatial performance. These results suggest that early visual experience has an important role in the development of spatial cognition, even when the visual input during the critical period of visual calibration is partially degraded like in the case of low vision children. Overall these results shed light on the importance of early assessment of spatial impairments in visually impaired children and early intervention to prevent the risk of isolation and social exclusion. PMID:28443040

The effects of simulated vision impairments on the cone of gaze.

PubMed

Hecht, Heiko; Hörichs, Jenny; Sheldon, Sarah; Quint, Jessilin; Bowers, Alex

2015-10-01

Detecting the gaze direction of others is critical for many social interactions. We explored factors that may make the perception of mutual gaze more difficult, including the degradation of the stimulus and simulated vision impairment. To what extent do these factors affect the complex assessment of mutual gaze? Using an interactive virtual head whose eye direction could be manipulated by the subject, we conducted two experiments to assess the effects of simulated vision impairments on mutual gaze. Healthy subjects had to demarcate the center and the edges of the cone of gaze-that is, the range of gaze directions that are accepted for mutual gaze. When vision was impaired by adding a semitransparent white contrast reduction mask to the display (Exp. 1), judgments became more variable and more influenced by the head direction (indicative of a compensation strategy). When refractive blur was added (Exp. 1), the gaze cone shrank from 12.9° (no blur) to 11.3° (3-diopter lens), which cannot be explained by a low-level process but might reflect a tightening of the criterion for mutual gaze as a response to the increased uncertainty. However, the overall effects of the impairments were relatively modest. Elderly subjects (Exp. 2) produced more variability but did not differ qualitatively from the younger subjects. In the face of artificial vision impairments, compensation mechanisms and criterion changes allow us to perform better in mutual gaze perception than would be predicted by a simple extrapolation from the losses in basic visual acuity and contrast sensitivity.

[Not Available].

PubMed

Zouaoui-Kesraoui, N; Derdour, A

2009-06-30

Les accidents dus aux pétards sont des accidents graves. Leur recrudescence ces dernières années en Algérie, essentiellement durant les fêtes du Mawlid Ennabaoui (fête de la naissance du prophète), mérite à notre sens d'entreprendre des bilans exhaustifs dont celui-ci dans le but d'une sensibilisation de toutes les compétences concernées. Nous avons réuni sur trois années consécutives (2002, 2003, 2004) 60 dossiers de malades ayant subi des accidents oculaires par pétards. Nos patients sont répartis en 42 consultations pour blessures légères et 18 hospitalisations pour blessures graves. Parmi ces derniers, neuf ont présenté des complications et séquelles graves (cinq cas de cécité par atrophie du globe oculaire, trois cas de cécité cornéenne et un cas de cécité par trou maculaire). Dans tous ces cas l'incapacité permanente partielle est au minimum de 30%. Au vu de ces données nous proposons des mesures d'éducation sanitaire et une sensibilisation du grand public aux traumatismes oculaires, par le biais de mé dias appropriés: radio, télévision, affiches.

QUELS FUTURS TRAITEMENTS POUR LA DEPENDANCE AU TABAC ET AU CANNABIS?

PubMed Central

LE FOLL, Bernard; JUSTINOVA, Zuzana; TANDA, Gianlugi; GOLDBERG, Steven R.

2009-01-01

RESUME Plus de trois millions de morts sont attribués au tabagisme dans le monde par an, et l’usage de tabac est en progression dans les pays en voie de développement. L’usage de tabac est donc une des rares causes de mortalité qui augmente, avec une prévision de plus de 10 millions de morts par an dans 30–40 ans. Le cannabis ou marijuana est la drogue illicite la plus consommée dans le monde et il n’y a actuellement pas de traitement disponible. Bien que les systèmes dopaminergiques jouent un rôle central dans les effets renforçants des drogues, d’autres systèmes sont impliqués. Nous présentons ici des résultats récents obtenus avec des antagonistes des récepteurs cannabinoides CB1, des récepteurs D3 de la dopamine et des récepteurs opioïdes. Ces antagonistes qui modulent de façon directe ou indirecte la transmission dopaminergique cérébrale représentent des approches prometteuses pour le traitement du tabagisme ou de la dépendance au cannabis. Ces approches sont à valider dans des essais cliniques. PMID:18663981

Broad-based visual benefits from training with an integrated perceptual-learning video game.

PubMed

Deveau, Jenni; Lovcik, Gary; Seitz, Aaron R

2014-06-01

Perception is the window through which we understand all information about our environment, and therefore deficits in perception due to disease, injury, stroke or aging can have significant negative impacts on individuals' lives. Research in the field of perceptual learning has demonstrated that vision can be improved in both normally seeing and visually impaired individuals, however, a limitation of most perceptual learning approaches is their emphasis on isolating particular mechanisms. In the current study, we adopted an integrative approach where the goal is not to achieve highly specific learning but instead to achieve general improvements to vision. We combined multiple perceptual learning approaches that have individually contributed to increasing the speed, magnitude and generality of learning into a perceptual-learning based video-game. Our results demonstrate broad-based benefits of vision in a healthy adult population. Transfer from the game includes; improvements in acuity (measured with self-paced standard eye-charts), improvement along the full contrast sensitivity function, and improvements in peripheral acuity and contrast thresholds. The use of this type of this custom video game framework built up from psychophysical approaches takes advantage of the benefits found from video game training while maintaining a tight link to psychophysical designs that enable understanding of mechanisms of perceptual learning and has great potential both as a scientific tool and as therapy to help improve vision. Copyright © 2014 Elsevier B.V. All rights reserved.

Barriers to accessing low vision services.

PubMed

Pollard, Tamara L; Simpson, John A; Lamoureux, Ecosse L; Keeffe, Jill E

2003-07-01

To investigate barriers to accessing low vision services in Australia. Adults with a vision impairment (<6/12 in the better eye and/or significant visual field defect), who were current patients at the Royal Victorian Eye and Ear Hospital (RVEEH), were interviewed. The questions investigated self-perceived vision difficulties, duration of vision loss and satisfaction with vision and also examined issues of awareness of low vision services and referral to services. Focus groups were also conducted with vision impaired (<6/12 in the better eye) patients from the RVEEH, listeners of the Radio for the Print Handicapped and peer workers at Vision Australia Foundation. The discussions were recorded and transcribed. The questionnaire revealed that referral to low vision services was associated with a greater degree of vision loss (p = 0.002) and a greater self-perception of low vision (p = 0.005) but that referral was not associated with satisfaction (p = 0.144) or difficulties related to vision (p = 0.169). Participants with mild and moderate vision impairment each reported similar levels of difficulties with daily activities and satisfaction with their vision (p > 0.05). However, there was a significant difference in the level of difficulties experienced with daily activities between those with mild-moderate and severe vision impairment (p < 0.05). The participants of the focus groups identified barriers to accessing low vision services related to awareness of services among the general public and eye care professionals, understanding of low vision and the services available, acceptance of low vision, the referral process, and transport. In addition to the expected difficulties with lack of awareness of services by people with low vision, many people do not understand what the services provide and do not identify themselves as having low vision. Knowledge of these barriers, from the perspective of people with low vision, can now be used to guide the development and content of future health-promotion campaigns.

The impact on vision of aspheric to spherical monofocal intraocular lenses in cataract surgery: a systematic review with meta-analysis.

PubMed

Schuster, Alexander K; Tesarz, Jonas; Vossmerbaeumer, Urs

2013-11-01

To provide a summary of the impact on vision of an aspheric intraocular lens (IOL) compared with a spherical IOL in cataract surgery. Systematic review with meta-analysis. Patients from published randomized controlled trials (RCTs) of cataract surgery with aspheric compared with spherical monofocal IOL implantation. We systematically searched the peer-reviewed literature in MEDLINE, EMBASE, Web of Science, BIOSIS, and the Cochrane Library according to the Cochrane Collaboration method to identify relevant RCTs. The inclusion criteria were RCTs on cataract surgery comparing the use of aspheric versus spherical IOL implantation that assessed visual acuity, contrast sensitivity, or quality of vision. The effects were calculated as mean differences or standardized mean differences (Hedges' g) and pooled using random-effect models. Best-corrected visual acuity (BCVA), contrast sensitivity, and subjective perception of the quality of vision. Forty-three studies provided data and were included, comprising 2076 eyes implanted with aspheric IOLs and 2034 eyes implanted with spherical IOLs. The BCVA showed a significant difference for aspheric IOLs (-0.01 logarithm of the minimum angle of resolution; 95% confidence interval [CI], -0.02 to -0.00). For contrast sensitivity, a significant advantage for aspheric IOLs was found under photopic and mesopic light conditions (photopic: Hedges' g 0.42, 95% CI 0.24-0.61 (3 cycles per degree [cpd]) to 0.53, 95% CI 0.33-0.73 (12 cpd); mesopic: Hedges' g 0.49, 95% CI 0.23-0.75 (1.5 cpd) to 0.76, 95% CI 0.52-1.00 (18 cpd)). Questionnaires targeting the subjective perception of quality of vision yielded less conclusive results. Overall, a patient may achieve better contrast sensitivity with an aspheric IOL than with a spherical IOL, especially under dim light. There was no clinically relevant difference in BCVA between aspheric and spherical IOL implantation. The findings on the subjective perception of visual quality were heterogeneous with no clear result favoring either option. Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Advances in understanding the molecular basis of the first steps in color vision.

PubMed

Hofmann, Lukas; Palczewski, Krzysztof

2015-11-01

Serving as one of our primary environmental inputs, vision is the most sophisticated sensory system in humans. Here, we present recent findings derived from energetics, genetics and physiology that provide a more advanced understanding of color perception in mammals. Energetics of cis-trans isomerization of 11-cis-retinal accounts for color perception in the narrow region of the electromagnetic spectrum and how human eyes can absorb light in the near infrared (IR) range. Structural homology models of visual pigments reveal complex interactions of the protein moieties with the light sensitive chromophore 11-cis-retinal and that certain color blinding mutations impair secondary structural elements of these G protein-coupled receptors (GPCRs). Finally, we identify unsolved critical aspects of color tuning that require future investigation. Copyright © 2015. Published by Elsevier Ltd.

Helicopter pilot estimation of self-altitude in a degraded visual environment

NASA Astrophysics Data System (ADS)

Crowley, John S.; Haworth, Loran A.; Szoboszlay, Zoltan P.; Lee, Alan G.

2000-06-01

The effect of night vision devices and degraded visual imagery on self-attitude perception is unknown. Thirteen Army aviators with normal vision flew five flights under various visual conditions in a modified AH-1 (Cobra) helicopter. Subjects estimated their altitude or flew to specified altitudes while flying a series of maneuvers. The results showed that subjects were better at detecting and controlling changes in altitude than they were at flying to or naming a specific altitude. In cruise flight and descent, the subjects tended to fly above the desired altitude, an error in the safe direction. While hovering, the direction of error was less predictable. In the low-level cruise flight scenario tested in this study, altitude perception was affected more by changes in image resolution than by changes in FOV or ocularity.

Image processing strategies based on saliency segmentation for object recognition under simulated prosthetic vision.

PubMed

Li, Heng; Su, Xiaofan; Wang, Jing; Kan, Han; Han, Tingting; Zeng, Yajie; Chai, Xinyu

2018-01-01

Current retinal prostheses can only generate low-resolution visual percepts constituted of limited phosphenes which are elicited by an electrode array and with uncontrollable color and restricted grayscale. Under this visual perception, prosthetic recipients can just complete some simple visual tasks, but more complex tasks like face identification/object recognition are extremely difficult. Therefore, it is necessary to investigate and apply image processing strategies for optimizing the visual perception of the recipients. This study focuses on recognition of the object of interest employing simulated prosthetic vision. We used a saliency segmentation method based on a biologically plausible graph-based visual saliency model and a grabCut-based self-adaptive-iterative optimization framework to automatically extract foreground objects. Based on this, two image processing strategies, Addition of Separate Pixelization and Background Pixel Shrink, were further utilized to enhance the extracted foreground objects. i) The results showed by verification of psychophysical experiments that under simulated prosthetic vision, both strategies had marked advantages over Direct Pixelization in terms of recognition accuracy and efficiency. ii) We also found that recognition performance under two strategies was tied to the segmentation results and was affected positively by the paired-interrelated objects in the scene. The use of the saliency segmentation method and image processing strategies can automatically extract and enhance foreground objects, and significantly improve object recognition performance towards recipients implanted a high-density implant. Copyright © 2017 Elsevier B.V. All rights reserved.

Sharpening vision by adapting to flicker

PubMed Central

Arnold, Derek H.; Williams, Jeremy D.; Phipps, Natasha E.; Goodale, Melvyn A.

2016-01-01

Human vision is surprisingly malleable. A static stimulus can seem to move after prolonged exposure to movement (the motion aftereffect), and exposure to tilted lines can make vertical lines seem oppositely tilted (the tilt aftereffect). The paradigm used to induce such distortions (adaptation) can provide powerful insights into the computations underlying human visual experience. Previously spatial form and stimulus dynamics were thought to be encoded independently, but here we show that adaptation to stimulus dynamics can sharpen form perception. We find that fast flicker adaptation (FFAd) shifts the tuning of face perception to higher spatial frequencies, enhances the acuity of spatial vision—allowing people to localize inputs with greater precision and to read finer scaled text, and it selectively reduces sensitivity to coarse-scale form signals. These findings are consistent with two interrelated influences: FFAd reduces the responsiveness of magnocellular neurons (which are important for encoding dynamics, but can have poor spatial resolution), and magnocellular responses contribute coarse spatial scale information when the visual system synthesizes form signals. Consequently, when magnocellular responses are mitigated via FFAd, human form perception is transiently sharpened because “blur” signals are mitigated. PMID:27791115

Lack of follow-up exams after failed school vision screenings: an investigation of contributing factors.

PubMed

Kimel, Linda S

2006-06-01

Programs to facilitate professional eye exams after failed school vision screenings often are based on the assumption that funding and access to services are major obstacles to care. Despite such programs, many children do not receive professional exams. The purpose of this study was to identify additional barriers to follow-up eye care. School nurses in an urban, midwestern public school district identified elementary school students who had not received follow-up eye exams after failed school vision screenings. Parents of these students were interviewed during the summer to determine financial, logistical, social/family, and perceptual barriers to care. Family issues, parental perceptions of vision problems, and difficulty planning ahead were found to be significant factors. Strategies to increase follow-up compliance and recommendations for overcoming barriers to care were also identified.

Visual Motion Perception and Visual Attentive Processes.

DTIC Science & Technology

1988-04-01

88-0551 Visual Motion Perception and Visual Attentive Processes George Spering , New YorkUnivesity A -cesson For DTIC TAB rant AFOSR 85-0364... Spering . HIPSt: A Unix-based image processing syslem. Computer Vision, Graphics, and Image Processing, 1984,25. 331-347. ’HIPS is the Human Information...Processing Laboratory’s Image Processing System. 1985 van Santen, Jan P. It, and George Spering . Elaborated Reichardt detectors. Journal of the Optical

Operational Based Vision Assessment Research: Depth Perception

DTIC Science & Technology

2014-11-01

13-072 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) USAF School of Aerospace Medicine...Aeromedical Research Department 2510 Fifth St. Wright-Patterson AFB, OH 45433-7913 8. PERFORMING ORGANIZATION REPORT NUMBER AFRL-SA-WP-JA-2014...tests are tests of stereopsis, such as the AFVT and AO Vectograph. Others evaluate depth perception with stereo as a contributor to performance , such

Accuracy aspects of stereo side-looking radar. [analysis of its visual perception and binocular vision

NASA Technical Reports Server (NTRS)

Leberl, F. W.

1979-01-01

The geometry of the radar stereo model and factors affecting visual radar stereo perception are reviewed. Limits to the vertical exaggeration factor of stereo radar are defined. Radar stereo model accuracies are analyzed with respect to coordinate errors caused by errors of radar sensor position and of range, and with respect to errors of coordinate differences, i.e., cross-track distances and height differences.

Perception of Motion in Statistically-Defined Displays

DTIC Science & Technology

1989-04-15

psychophysical study before. He was paid $7.50/hour for his participation. Also, to insure high motivation , he received an additional one cent for every...correct response. This was the same motivational device used in the earlier work on motion discrimination (Ball and Sekuler, 1982). The observer...scientists, physiologists, and people interested in computer vision. Finally, one of the main motives for studying motion perception is a desire to

Cochlear Implantation in Siblings With Refsum's Disease.

PubMed

Stähr, Kerstin; Kuechler, Alma; Gencik, Martin; Arnolds, Judith; Dendy, Meaghan; Lang, Stephan; Arweiler-Harbeck, Diana

2017-08-01

Whether the origin of severe hearing loss in Refsum's syndrome is caused by cochlear impairment or retrocochlear degeneration remains unclear. This case report aims to investigate hearing performance before and after cochlear implantation to shed light on this question. Also, identification of new mutations causing Refsum's syndrome would be helpful in generating additional means of diagnosis. A family of 4 individuals was subjected to genetic testing. Two siblings (56 and 61 years old) suffered from severe hearing and vision loss and received bilateral cochlear implants. Genetic analysis, audiological outcome, and clinical examinations were performed. One new mutation in the PHYH gene (c.768del63bp) causing Refsum's disease was found. Preoperative distortion product otoacoustic emissions (DPAOEs) were absent. Postoperative speech perception in Freiburger speech test was 100% for bisyllabic words and 85% (patient No. 1) and 65% (patient No. 2), respectively, for monosyllabic words. Five years after implantation, speech perception remained stable for bisyllabic words but showed decreasing capabilities for monosyllabic words. A new mutation causing Refsum's disease is presented. Cochlear implantation in case of severe hearing loss leads to an improvement in speech perception and should be recommended for patients with Refsum's disease, especially when the hearing loss is combined with a severe loss of vision. Decrease of speech perception in the long-term follow-up could indicate an additional retrocochlear degeneration.

Are visual peripheries forever young?

PubMed

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.

Peripheral Vision of Youths with Low Vision: Motion Perception, Crowding, and Visual Search

PubMed Central

Tadin, Duje; Nyquist, Jeffrey B.; Lusk, Kelly E.; Corn, Anne L.; Lappin, Joseph S.

2012-01-01

Purpose. Effects of low vision on peripheral visual function are poorly understood, especially in children whose visual skills are still developing. The aim of this study was to measure both central and peripheral visual functions in youths with typical and low vision. Of specific interest was the extent to which measures of foveal function predict performance of peripheral tasks. Methods. We assessed central and peripheral visual functions in youths with typical vision (n = 7, ages 10–17) and low vision (n = 24, ages 9–18). Experimental measures used both static and moving stimuli and included visual crowding, visual search, motion acuity, motion direction discrimination, and multitarget motion comparison. Results. In most tasks, visual function was impaired in youths with low vision. Substantial differences, however, were found both between participant groups and, importantly, across different tasks within participant groups. Foveal visual acuity was a modest predictor of peripheral form vision and motion sensitivity in either the central or peripheral field. Despite exhibiting normal motion discriminations in fovea, motion sensitivity of youths with low vision deteriorated in the periphery. This contrasted with typically sighted participants, who showed improved motion sensitivity with increasing eccentricity. Visual search was greatly impaired in youths with low vision. Conclusions. Our results reveal a complex pattern of visual deficits in peripheral vision and indicate a significant role of attentional mechanisms in observed impairments. These deficits were not adequately captured by measures of foveal function, arguing for the importance of independently assessing peripheral visual function. PMID:22836766

Short-Term Neural Adaptation to Simultaneous Bifocal Images

PubMed Central

Radhakrishnan, Aiswaryah; Dorronsoro, Carlos; Sawides, Lucie; Marcos, Susana

2014-01-01

Simultaneous vision is an increasingly used solution for the correction of presbyopia (the age-related loss of ability to focus near images). Simultaneous Vision corrections, normally delivered in the form of contact or intraocular lenses, project on the patient's retina a focused image for near vision superimposed with a degraded image for far vision, or a focused image for far vision superimposed with the defocused image of the near scene. It is expected that patients with these corrections are able to adapt to the complex Simultaneous Vision retinal images, although the mechanisms or the extent to which this happens is not known. We studied the neural adaptation to simultaneous vision by studying changes in the Natural Perceived Focus and in the Perceptual Score of image quality in subjects after exposure to Simultaneous Vision. We show that Natural Perceived Focus shifts after a brief period of adaptation to a Simultaneous Vision blur, similar to adaptation to Pure Defocus. This shift strongly correlates with the magnitude and proportion of defocus in the adapting image. The magnitude of defocus affects perceived quality of Simultaneous Vision images, with 0.5 D defocus scored lowest and beyond 1.5 D scored “sharp”. Adaptation to Simultaneous Vision shifts the Perceptual Score of these images towards higher rankings. Larger improvements occurred when testing simultaneous images with the same magnitude of defocus as the adapting images, indicating that wearing a particular bifocal correction improves the perception of images provided by that correction. PMID:24664087

Oculocutaneous albinism: identifying and overcoming barriers to vision care in a Nigerian population.

PubMed

Udeh, N N; Eze, B I; Onwubiko, S N; Arinze, O C; Onwasigwe, E N; Umeh, R E

2014-06-01

To assess eye care service utilization, and identify access barriers in a south-eastern Nigerian albino population. The study was a population-based, cross-sectional survey conducted in Enugu state between August, 2011 and January, 2012. Using the data base of the state's Albino Foundation and tailored awareness creation, persons living with albinism were identified and recruited at two study centres. Data on participants' socio-demographics, perception of vision, visual needs, previous eye examination and or low vision assessment, use of glasses or low vision devices were collected. Reasons for non-utilisation of available vision care services were also obtained. Descriptive and comparative statistics were performed. A p < 0.05 was considered statistically significant. The participants (n = 153; males 70; females 83; sex ratio: 1:1.1) were aged 23.46 + 10.44 SD years (range 6-60 years). Most--95.4 % of the participants had no previous low vision assessment and none--0.0% had used low vision device. Of the participants, 82.4% reported previous eye examination, 33.3% had not used spectacles previously, despite the existing need. Ignorance--88.9% and poor access--8.5% were the main barriers to uptake of vision care services. In Enugu, Nigeria, there is poor awareness and low utilization of vision care services among people with albinism. The identified barriers to vision care access are amenable to awareness creation and logistic change in the provision of appropriate vision care services.

Peripheral vision of youths with low vision: motion perception, crowding, and visual search.

PubMed

Tadin, Duje; Nyquist, Jeffrey B; Lusk, Kelly E; Corn, Anne L; Lappin, Joseph S

2012-08-24

Effects of low vision on peripheral visual function are poorly understood, especially in children whose visual skills are still developing. The aim of this study was to measure both central and peripheral visual functions in youths with typical and low vision. Of specific interest was the extent to which measures of foveal function predict performance of peripheral tasks. We assessed central and peripheral visual functions in youths with typical vision (n = 7, ages 10-17) and low vision (n = 24, ages 9-18). Experimental measures used both static and moving stimuli and included visual crowding, visual search, motion acuity, motion direction discrimination, and multitarget motion comparison. In most tasks, visual function was impaired in youths with low vision. Substantial differences, however, were found both between participant groups and, importantly, across different tasks within participant groups. Foveal visual acuity was a modest predictor of peripheral form vision and motion sensitivity in either the central or peripheral field. Despite exhibiting normal motion discriminations in fovea, motion sensitivity of youths with low vision deteriorated in the periphery. This contrasted with typically sighted participants, who showed improved motion sensitivity with increasing eccentricity. Visual search was greatly impaired in youths with low vision. Our results reveal a complex pattern of visual deficits in peripheral vision and indicate a significant role of attentional mechanisms in observed impairments. These deficits were not adequately captured by measures of foveal function, arguing for the importance of independently assessing peripheral visual function.

Neural Networks for Computer Vision: A Framework for Specifications of a General Purpose Vision System

NASA Astrophysics Data System (ADS)

Skrzypek, Josef; Mesrobian, Edmond; Gungner, David J.

1989-03-01

The development of autonomous land vehicles (ALV) capable of operating in an unconstrained environment has proven to be a formidable research effort. The unpredictability of events in such an environment calls for the design of a robust perceptual system, an impossible task requiring the programming of a system bases on the expectation of future, unconstrained events. Hence, the need for a "general purpose" machine vision system that is capable of perceiving and understanding images in an unconstrained environment in real-time. The research undertaken at the UCLA Machine Perception Laboratory addresses this need by focusing on two specific issues: 1) the long term goals for machine vision research as a joint effort between the neurosciences and computer science; and 2) a framework for evaluating progress in machine vision. In the past, vision research has been carried out independently within different fields including neurosciences, psychology, computer science, and electrical engineering. Our interdisciplinary approach to vision research is based on the rigorous combination of computational neuroscience, as derived from neurophysiology and neuropsychology, with computer science and electrical engineering. The primary motivation behind our approach is that the human visual system is the only existing example of a "general purpose" vision system and using a neurally based computing substrate, it can complete all necessary visual tasks in real-time.

A differential color flicker test for detecting acquired color vision impairment in multiple sclerosis and diabetic retinopathy.

PubMed

Gregori, Bruno; Papazachariadis, Odysseas; Farruggia, Alfonsa; Accornero, Neri

2011-01-15

Optic neuritis related to multiple sclerosis and diabetic retinopathy are relatively selective post-retinal and retinal vision disorders. Vision impairment in both conditions is reliably measured by testing critical fusion frequency (CFF). To examine color vision, we measured the CFF in response to red and blue stimuli, and tested CFF values in patients without evident vision impairment. To ensure that differences in CFF values in a given subject depended only on color perception we displayed red and blue flickering stimuli at equal luminance. CFF to red or blue stimuli were compared in patients with medical history of optic neuritis related to multiple sclerosis (post-retinal vision impairment), patients with diabetic retinopathy (retinal vision impairment) and healthy subjects. The test procedure disclosed altered CFF values for red and blue stimuli in both groups of patients studied. The comparison between the two groups disclosed a prevalent CFF impairment for red stimuli in patients with optic neuritis related to multiple sclerosis and for blue stimuli in patients with diabetic retinopathy. The differential color flicker test appears highly accurate in detecting color vision impairment. Comparison of the two color CFFs differentiates retinal from post-retinal visual disorders. Copyright © 2010 Elsevier B.V. All rights reserved.

Seeing without Seeing? Degraded Conscious Vision in a Blindsight Patient.

PubMed

Overgaard, Morten; Fehl, Katrin; Mouridsen, Kim; Bergholt, Bo; Cleeremans, Axel

2008-08-21

Blindsight patients, whose primary visual cortex is lesioned, exhibit preserved ability to discriminate visual stimuli presented in their "blind" field, yet report no visual awareness hereof. Blindsight is generally studied in experimental investigations of single patients, as very few patients have been given this "diagnosis". In our single case study of patient GR, we ask whether blindsight is best described as unconscious vision, or rather as conscious, yet severely degraded vision. In experiment 1 and 2, we successfully replicate the typical findings of previous studies on blindsight. The third experiment, however, suggests that GR's ability to discriminate amongst visual stimuli does not reflect unconscious vision, but rather degraded, yet conscious vision. As our finding results from using a method for obtaining subjective reports that has not previously used in blindsight studies (but validated in studies of healthy subjects and other patients with brain injury), our results call for a reconsideration of blindsight, and, arguably also of many previous studies of unconscious perception in healthy subjects.

Management of traumatic macular holes: case report.

PubMed

Brasil, Oswaldo Ferreira Moura; Brasil, Oswaldo Moura

2008-01-01

Traumatic macular hole is a disease whose pathogenesis is not fully understood and the best treatment guideline is controversial. We report 2 cases of traumatic macular hole with different treatment approaches. In the first case, a 9-year-old boy presented with a traumatic macular hole secondary to blunt ocular trauma with a stone, and initial vision of 20/300. He underwent surgical repair and his final vision was 20/70 with hole closure after a 1 year follow-up. In the second case, a 20-year-old woman suffered a penetrating bullet wound on the left side of her forehead. The injury caused optic nerve head avulsion in the left eye with loss of light perception. The right eye had a traumatic macular hole and signs suggestive of sclopetaria chorioretinitis, with 20/60 vision. This case was initially observed and vision improved to 20/30 with reduction of the hole diameter. Vision and hole diameter remained stable after 8 months.

A balancing act: physical balance, through arousal, influences size perception.

PubMed

Geuss, Michael N; Stefanucci, Jeanine K; de Benedictis-Kessner, Justin; Stevens, Nicholas R

2010-10-01

Previous research has demonstrated that manipulating vision influences balance. Here, we question whether manipulating balance can influence vision and how it may influence vision--specifically, the perception of width. In Experiment 1, participants estimated the width of beams while balanced and unbalanced. When unbalanced, participants judged the widths to be smaller. One possible explanation is that unbalanced participants did not view the stimulus as long as when balanced because they were focused on remaining balanced. In Experiment 2, we tested this notion by limiting viewing time. Experiment 2 replicated the findings of Experiment 1, but viewing time had no effect on width judgments. In Experiment 3, participants' level of arousal was manipulated, because the balancing task likely produced arousal. While jogging, participants judged the beams to be smaller. In Experiment 4, participants completed another arousing task (counting backward by sevens) that did not involve movement. Again, participants judged the beams to be smaller when aroused. Experiment 5A raised participants' level of arousal before estimating the board widths (to control for potential dual-task effects) and showed that heightened arousal still influenced perceived width of the boards. Collectively, heightened levels of arousal, caused by multiple manipulations (including balance), influenced perceived width.

Perception-based synthetic cueing for night vision device rotorcraft hover operations

NASA Astrophysics Data System (ADS)

Bachelder, Edward N.; McRuer, Duane

2002-08-01

Helicopter flight using night-vision devices (NVDs) is difficult to perform, as evidenced by the high accident rate associated with NVD flight compared to day operation. The approach proposed in this paper is to augment the NVD image with synthetic cueing, whereby the cues would emulate position and motion and appear to be actually occurring in physical space on which they are overlaid. Synthetic cues allow for selective enhancement of perceptual state gains to match the task requirements. A hover cue set was developed based on an analogue of a physical target used in a flight handling qualities tracking task, a perceptual task analysis for hover, and fundamentals of human spatial perception. The display was implemented on a simulation environment, constructed using a virtual reality device, an ultrasound head-tracker, and a fixed-base helicopter simulator. Seven highly trained helicopter pilots were used as experimental subjects and tasked to maintain hover in the presence of aircraft positional disturbances while viewing a synthesized NVD environment and the experimental hover cues. Significant performance improvements were observed when using synthetic cue augmentation. This paper demonstrates that artificial magnification of perceptual states through synthetic cueing can be an effective method of improving night-vision helicopter hover operations.

Vision as a user interface

NASA Astrophysics Data System (ADS)

Koenderink, Jan

2011-03-01

The egg-rolling behavior of the graylag goose is an often quoted example of a fixed-action pattern. The bird will even attempt to roll a brick back to its nest! Despite excellent visual acuity it apparently takes a brick for an egg." Evolution optimizes utility, not veridicality. Yet textbooks take it for a fact that human vision evolved so as to approach veridical perception. How do humans manage to dodge the laws of evolution? I will show that they don't, but that human vision is an idiosyncratic user interface. By way of an example I consider the case of pictorial perception. Gleaning information from still images is an important human ability and is likely to remain so for the foreseeable future. I will discuss a number of instances of extreme non-veridicality and huge inter-observer variability. Despite their importance in applications (information dissemination, personnel selection,...) such huge effects have remained undocumented in the literature, although they can be traced to artistic conventions. The reason appears to be that conventional psychophysics-by design-fails to address the qualitative, that is the meaningful, aspects of visual awareness whereas this is the very target of the visual arts.

AI And Early Vision - Part II

NASA Astrophysics Data System (ADS)

Julesz, Bela

1989-08-01

A quarter of a century ago I introduced two paradigms into psychology which in the intervening years have had a direct impact on the psychobiology of early vision and an indirect one on artificial intelligence (AI or machine vision). The first, the computer-generated random-dot stereogram (RDS) paradigm (Julesz, 1960) at its very inception posed a strategic question both for AI and neurophysiology. The finding that stereoscopic depth perception (stereopsis) is possible without the many enigmatic cues of monocular form recognition - as assumed previously - demonstrated that stereopsis with its basic problem of finding matches between corresponding random aggregates of dots in the left and right visual fields became ripe for modeling. Indeed, the binocular matching problem of stereopsis opened up an entire field of study, eventually leading to the computational models of David Marr (1982) and his coworkers. The fusion of RDS had an even greater impact on neurophysiologists - including Hubel and Wiesel (1962) - who realized that stereopsis must occur at an early stage, and can be studied easier than form perception. This insight recently culminated in the studies by Gian Poggio (1984) who found binocular-disparity - tuned neurons in the input stage to the visual cortex (layer IVB in V1) in the monkey that were selectively triggered by dynamic RDS. Thus the first paradigm led to a strategic insight: that with stereoscopic vision there is no camouflage, and as such was advantageous for our primate ancestors to evolve the cortical machinery of stereoscopic vision to capture camouflaged prey (insects) at a standstill. Amazingly, although stereopsis evolved relatively late in primates, it captured the very input stages of the visual cortex. (For a detailed review, see Julesz, 1986a)

[Clinical characteristics of paraneoplastic retinopathy and optic neuropathy].

PubMed

Huang, Hou-bin; Wei, Shi-hui; Li, Ying; Wang, Feng-xiang; Yao, Yi; Jiang, Cai-hui; Yin, Zheng-qin; Zhang, Mao-nian; Wei, Wen-bin

2013-06-01

To analyze the clinical characteristics of paraneoplastic retinopathy and optic neuropathy(PRON). Case series study. Eight patients were enrolled from October 2006 to March 2012 visited in ophthalmology department, the People Liberation Army General Hospital. The patients were underwent a series of examinations, including fundus photography, visual electrophysiology, fundus fluorescein angiography, optic coherent tomography,fundus autofluorescent imaging, perimetry, ultrasonography, magnetic resonance imaging, spinal tap and cerebrospinal fluid test, paraneoplastic syndrome (PNS) antibody test. The patients were followed up in outpatient department and(or) by phone. The clinical manifestation,entity types, and treatment were analyzed. Of the eight patients, there were cancer associated retinopathy(CAR) 3 cases, bilateral diffuse uveal melanocytic proliferation (BDUMP) 2 cases and paraneoplastic optic neuropathy(PON) 3 cases. Five patients were detected the PNS antibodies and revealed three patients with positive results. As for the primary malignancy,four of the eight patients were lung carcinoma,others included invasive thymoma, kidney cancer, acute lymphocytic leukemia and cervical cancer, each for one case. All the patients complained vision blurring or progressive visual decrease. Other complaints included dark shadow in two patients, shimmering, dazzling, double vision and eye pain, each in one patient. One patient complained progressive decreased vision in both eyes prior to the diagnosis of lung cancer. Of the 16 eyes of the eight patients, there were six patients with no light perception vision, five from light perception to 0.05, and other five with no less than 0.4 vision, in the end of the follow up. Five patients were treated with steroid with unsatisfactory efficacy. Each entity of PRON has its own clinical characteristics. PRON especially BDUMP may be a pre-metastatic disease.

Perception and eye movements in simulated traffic situations.

PubMed

Luoma, J

1984-01-01

In an experiment to simulate the perception task of a driver, subjects were shown uninterrupted series of colour slides of different kinds of highway scenes. The dependent variables were eye fixations, fixation times and conscious perceptions for the part of the traffic signs and roadside advertisements. Perceptions were achieved mostly as a result of fixation, but partly also by using peripheral vision. On the other hand fixation did not always cause perception. The lengthening of fixation time increased the number of correct perceptions. When the traffic sign and the roadside advertisement were in the same slide, the advertisement disturbed the perception of the sign, but in the daylight conditions this effect was not noticed as an alteration of the fixation of the sign, but as prevention of further information processing. The disturbing influence of the advertisement was increased by its bad information ergonomics which caused a long fixation time.

Experiments on shape perception in stereoscopic displays

NASA Astrophysics Data System (ADS)

Leroy, Laure; Fuchs, Philippe; Paljic, Alexis; Moreau, Guillaume

2009-02-01

Stereoscopic displays are increasingly used for computer-aided design. The aim is to make virtual prototypes to avoid building real ones, so that time, money and raw materials are saved. But do we really know whether virtual displays render the objects in a realistic way to potential users? In this study, we have performed several experiments in which we compare two virtual shapes to their equivalent in the real world, each of these aiming at a specific issue by a comparison: First, we performed some perception tests to evaluate the importance of head tracking to evaluate if it is better to concentrate our efforts on stereoscopic vision; Second, we have studied the effects of interpupillary distance; Third, we studied the effects of the position of the main object in comparison with the screen. Two different tests are used, the first one using a well-known shape (a sphere) and the second one using an irregular shape but with almost the same colour and dimension. These two tests allow us to determine if symmetry is important in their perception. We show that head tracking has a more important effect on shape perception than stereoscopic vision, especially on depth perception because the subject is able to move around the scene. The study also shows that an object between the subject and the screen is perceived better than an object which is on the screen, even if the latter is better for the eye strain.

Focal and Ambient Processing of Built Environments: Intellectual and Atmospheric Experiences of Architecture

PubMed Central

Rooney, Kevin K.; Condia, Robert J.; Loschky, Lester C.

2017-01-01

Neuroscience has well established that human vision divides into the central and peripheral fields of view. Central vision extends from the point of gaze (where we are looking) out to about 5° of visual angle (the width of one’s fist at arm’s length), while peripheral vision is the vast remainder of the visual field. These visual fields project to the parvo and magno ganglion cells, which process distinctly different types of information from the world around us and project that information to the ventral and dorsal visual streams, respectively. Building on the dorsal/ventral stream dichotomy, we can further distinguish between focal processing of central vision, and ambient processing of peripheral vision. Thus, our visual processing of and attention to objects and scenes depends on how and where these stimuli fall on the retina. The built environment is no exception to these dependencies, specifically in terms of how focal object perception and ambient spatial perception create different types of experiences we have with built environments. We argue that these foundational mechanisms of the eye and the visual stream are limiting parameters of architectural experience. We hypothesize that people experience architecture in two basic ways based on these visual limitations; by intellectually assessing architecture consciously through focal object processing and assessing architecture in terms of atmosphere through pre-conscious ambient spatial processing. Furthermore, these separate ways of processing architectural stimuli operate in parallel throughout the visual perceptual system. Thus, a more comprehensive understanding of architecture must take into account that built environments are stimuli that are treated differently by focal and ambient vision, which enable intellectual analysis of architectural experience versus the experience of architectural atmosphere, respectively. We offer this theoretical model to help advance a more precise understanding of the experience of architecture, which can be tested through future experimentation. (298 words) PMID:28360867

Focal and Ambient Processing of Built Environments: Intellectual and Atmospheric Experiences of Architecture.

PubMed

Rooney, Kevin K; Condia, Robert J; Loschky, Lester C

2017-01-01

Neuroscience has well established that human vision divides into the central and peripheral fields of view. Central vision extends from the point of gaze (where we are looking) out to about 5° of visual angle (the width of one's fist at arm's length), while peripheral vision is the vast remainder of the visual field. These visual fields project to the parvo and magno ganglion cells, which process distinctly different types of information from the world around us and project that information to the ventral and dorsal visual streams, respectively. Building on the dorsal/ventral stream dichotomy, we can further distinguish between focal processing of central vision, and ambient processing of peripheral vision. Thus, our visual processing of and attention to objects and scenes depends on how and where these stimuli fall on the retina. The built environment is no exception to these dependencies, specifically in terms of how focal object perception and ambient spatial perception create different types of experiences we have with built environments. We argue that these foundational mechanisms of the eye and the visual stream are limiting parameters of architectural experience. We hypothesize that people experience architecture in two basic ways based on these visual limitations; by intellectually assessing architecture consciously through focal object processing and assessing architecture in terms of atmosphere through pre-conscious ambient spatial processing. Furthermore, these separate ways of processing architectural stimuli operate in parallel throughout the visual perceptual system. Thus, a more comprehensive understanding of architecture must take into account that built environments are stimuli that are treated differently by focal and ambient vision, which enable intellectual analysis of architectural experience versus the experience of architectural atmosphere, respectively. We offer this theoretical model to help advance a more precise understanding of the experience of architecture, which can be tested through future experimentation. (298 words).

Brightness perception of unrelated self-luminous colors.

PubMed

Withouck, Martijn; Smet, Kevin A G; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Koenderink, Jan; Hanselaer, Peter

2013-06-01

The perception of brightness of unrelated self-luminous colored stimuli of the same luminance has been investigated. The Helmholtz-Kohlrausch (H-K) effect, i.e., an increase in brightness perception due to an increase in saturation, is clearly observed. This brightness perception is compared with the calculated brightness according to six existing vision models, color appearance models, and models based on the concept of equivalent luminance. Although these models included the H-K effect and half of them were developed to work with unrelated colors, none of the models seemed to be able to fully predict the perceived brightness. A tentative solution to increase the prediction accuracy of the color appearance model CAM97u, developed by Hunt, is presented.

Biological Basis For Computer Vision: Some Perspectives

NASA Astrophysics Data System (ADS)

Gupta, Madan M.

1990-03-01

Using biology as a basis for the development of sensors, devices and computer vision systems is a challenge to systems and vision scientists. It is also a field of promising research for engineering applications. Biological sensory systems, such as vision, touch and hearing, sense different physical phenomena from our environment, yet they possess some common mathematical functions. These mathematical functions are cast into the neural layers which are distributed throughout our sensory regions, sensory information transmission channels and in the cortex, the centre of perception. In this paper, we are concerned with the study of the biological vision system and the emulation of some of its mathematical functions, both retinal and visual cortex, for the development of a robust computer vision system. This field of research is not only intriguing, but offers a great challenge to systems scientists in the development of functional algorithms. These functional algorithms can be generalized for further studies in such fields as signal processing, control systems and image processing. Our studies are heavily dependent on the the use of fuzzy - neural layers and generalized receptive fields. Building blocks of such neural layers and receptive fields may lead to the design of better sensors and better computer vision systems. It is hoped that these studies will lead to the development of better artificial vision systems with various applications to vision prosthesis for the blind, robotic vision, medical imaging, medical sensors, industrial automation, remote sensing, space stations and ocean exploration.

The economics of motion perception and invariants of visual sensitivity.

PubMed

Gepshtein, Sergei; Tyukin, Ivan; Kubovy, Michael

2007-06-21

Neural systems face the challenge of optimizing their performance with limited resources, just as economic systems do. Here, we use tools of neoclassical economic theory to explore how a frugal visual system should use a limited number of neurons to optimize perception of motion. The theory prescribes that vision should allocate its resources to different conditions of stimulation according to the degree of balance between measurement uncertainties and stimulus uncertainties. We find that human vision approximately follows the optimal prescription. The equilibrium theory explains why human visual sensitivity is distributed the way it is and why qualitatively different regimes of apparent motion are observed at different speeds. The theory offers a new normative framework for understanding the mechanisms of visual sensitivity at the threshold of visibility and above the threshold and predicts large-scale changes in visual sensitivity in response to changes in the statistics of stimulation and system goals.

Mapping the Perceptual Grain of the Human Retina

PubMed Central

Tuten, William S.; Roorda, Austin; Sincich, Lawrence C.

2014-01-01

In humans, experimental access to single sensory receptors is difficult to achieve, yet it is crucial for learning how the signals arising from each receptor are transformed into perception. By combining adaptive optics microstimulation with high-speed eye tracking, we show that retinal function can be probed at the level of the individual cone photoreceptor in living eyes. Classical psychometric functions were obtained from cone-sized microstimuli targeted to single photoreceptors. Revealed psychophysically, the cone mosaic also manifests a variable sensitivity to light across its surface that accords with a simple model of cone light capture. Because this microscopic grain of vision could be detected on the perceptual level, it suggests that photoreceptors can act individually to shape perception, if the normally suboptimal relay of light by the eye's optics is corrected. Thus the precise arrangement of cones and the exact placement of stimuli onto those cones create the initial retinal limits on signals mediating spatial vision. PMID:24741057

Language Processing as Cue Integration: Grounding the Psychology of Language in Perception and Neurophysiology

PubMed Central

Martin, Andrea E.

2016-01-01

I argue that cue integration, a psychophysiological mechanism from vision and multisensory perception, offers a computational linking hypothesis between psycholinguistic theory and neurobiological models of language. I propose that this mechanism, which incorporates probabilistic estimates of a cue's reliability, might function in language processing from the perception of a phoneme to the comprehension of a phrase structure. I briefly consider the implications of the cue integration hypothesis for an integrated theory of language that includes acquisition, production, dialogue and bilingualism, while grounding the hypothesis in canonical neural computation. PMID:26909051

From dichoptic to dichotic: historical contrasts between binocular vision and binaural hearing.

PubMed

Wade, Nicholas J; Ono, Hiroshi

2005-01-01

Phenomena involving vision with two eyes have been commented upon for several thousand years whereas those concerned with hearing with two ears have a much more recent history. Studies of binocular vision and binaural hearing are contrasted with respect to the singleness of the percept, experimental manipulations of dichoptic and dichotic stimuli, eye and ear dominance, spatial localisation, and the instruments used to stimulate the paired organs. One of the principal phenomena that led to studies of dichotic hearing was dichoptic colour mixing. There was similar disagreement regarding whether colours or sounds could be combined when presented to different paired organs. Direction and distance in visual localisation were analysed before those for auditory localisation, partly due to difficulties in controlling the stimuli. Instruments for investigating binocular vision, like the stereoscope and pseudoscope, were invented before those for binaural hearing, like the stethophone and pseudophone.

Contact Lenses for Color Blindness.

PubMed

Badawy, Abdel-Rahman; Hassan, Muhammad Umair; Elsherif, Mohamed; Ahmed, Zubair; Yetisen, Ali K; Butt, Haider

2018-06-01

Color vision deficiency (color blindness) is an inherited genetic ocular disorder. While no cure for this disorder currently exists, several methods can be used to increase the color perception of those affected. One such method is the use of color filtering glasses which are based on Bragg filters. While these glasses are effective, they are high cost, bulky, and incompatible with other vision correction eyeglasses. In this work, a rhodamine derivative is incorporated in commercial contact lenses to filter out the specific wavelength bands (≈545-575 nm) to correct color vision blindness. The biocompatibility assessment of the dyed contact lenses in human corneal fibroblasts and human corneal epithelial cells shows no toxicity and cell viability remains at 99% after 72 h. This study demonstrates the potential of the dyed contact lenses in wavelength filtering and color vision deficiency management. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mediated-reality magnification for macular degeneration rehabilitation

NASA Astrophysics Data System (ADS)

Martin-Gonzalez, Anabel; Kotliar, Konstantin; Rios-Martinez, Jorge; Lanzl, Ines; Navab, Nassir

2014-10-01

Age-related macular degeneration (AMD) is a gradually progressive eye condition, which is one of the leading causes of blindness and low vision in the Western world. Prevailing optical visual aids compensate part of the lost visual function, but omitting helpful complementary information. This paper proposes an efficient magnification technique, which can be implemented on a head-mounted display, for improving vision of patients with AMD, by preserving global information of the scene. Performance of the magnification approach is evaluated by simulating central vision loss in normally sighted subjects. Visual perception was measured as a function of text reading speed and map route following speed. Statistical analysis of experimental results suggests that our magnification method improves reading speed 1.2 times and spatial orientation to find routes on a map 1.5 times compared to a conventional magnification approach, being capable to enhance peripheral vision of AMD subjects along with their life quality.

Comparing visual representations across human fMRI and computational vision

PubMed Central

Leeds, Daniel D.; Seibert, Darren A.; Pyles, John A.; Tarr, Michael J.

2013-01-01

Feedforward visual object perception recruits a cortical network that is assumed to be hierarchical, progressing from basic visual features to complete object representations. However, the nature of the intermediate features related to this transformation remains poorly understood. Here, we explore how well different computer vision recognition models account for neural object encoding across the human cortical visual pathway as measured using fMRI. These neural data, collected during the viewing of 60 images of real-world objects, were analyzed with a searchlight procedure as in Kriegeskorte, Goebel, and Bandettini (2006): Within each searchlight sphere, the obtained patterns of neural activity for all 60 objects were compared to model responses for each computer recognition algorithm using representational dissimilarity analysis (Kriegeskorte et al., 2008). Although each of the computer vision methods significantly accounted for some of the neural data, among the different models, the scale invariant feature transform (Lowe, 2004), encoding local visual properties gathered from “interest points,” was best able to accurately and consistently account for stimulus representations within the ventral pathway. More generally, when present, significance was observed in regions of the ventral-temporal cortex associated with intermediate-level object perception. Differences in model effectiveness and the neural location of significant matches may be attributable to the fact that each model implements a different featural basis for representing objects (e.g., more holistic or more parts-based). Overall, we conclude that well-known computer vision recognition systems may serve as viable proxies for theories of intermediate visual object representation. PMID:24273227

Sham radiation in clinical trials assessing radiotherapy for exudative age-related macular degeneration.

PubMed

Marcus, D M; Camp, M W; Sheils, W C; McIntosh, S B; Leibach, D B; Johnson, M H; Samy, C N

1999-01-01

To evaluate the effectiveness of sham radiation treatments in masking patients to their randomization group in the Radiation of Age-Related Macular Degeneration (ROARMD) Study. Patients with choroidal neovascularization complicating age-related macular degeneration were randomized to a treatment (RAD) group that received external beam irradiation (seven treatment sessions) or to a control (SHAM) group that received sham radiation (one sham treatment session). During a telephone survey, 62 of 73 randomized patients responded to the following questions: Do you think you received radiation? Why do you feel that way? Did the vision in your study eye worsen after enrollment? Eighty-one percent of the RAD group and 59% of the SHAM group thought that they had received radiation. In patients who thought that their vision had stabilized or improved, 82% thought that they had received radiation. In patients who thought that their vision was worse, only 39% thought that they had received radiation. In 54% of patients, subjective perception of vision influenced their guess as to whether they received radiation. Subjective patient perception of visual outcome was the most influential variable for masking. Variation between radiation treatment and sham session techniques, such as equipment used and duration of treatments, played a lesser role in the masking of patients. Seven treatment days correlated with a higher number of patients who thought that they had received radiation. Although our procedures do not strictly mask the two groups, one sham radiation session was effective in keeping patients guessing their randomization group.

Adaptation aftereffects in the perception of gender from biological motion.

PubMed

Troje, Nikolaus F; Sadr, Javid; Geyer, Henning; Nakayama, Ken

2006-07-28

Human visual perception is highly adaptive. While this has been known and studied for a long time in domains such as color vision, motion perception, or the processing of spatial frequency, a number of more recent studies have shown that adaptation and adaptation aftereffects also occur in high-level visual domains like shape perception and face recognition. Here, we present data that demonstrate a pronounced aftereffect in response to adaptation to the perceived gender of biological motion point-light walkers. A walker that is perceived to be ambiguous in gender under neutral adaptation appears to be male after adaptation with an exaggerated female walker and female after adaptation with an exaggerated male walker. We discuss this adaptation aftereffect as a tool to characterize and probe the mechanisms underlying biological motion perception.

Une fistule recto-vaginale rentrant dans le cadre d'un syndrome de Currarino

PubMed Central

Idrissi, Mounia Lakhdar; Babakhoya, Abdeladim; Bouabdellah, Youssef; Hida, Mostapha

2011-01-01

Le syndrome de Currarino (SC) est défini par une triade rassemblant une malformation ano-rectale, une agénésie sacrée et une tumeur pré-sacrée. Nous rapportons le cas d'une fille de 4 ans et demi ayant été admise en consultation de gastro-entérologie pédiatrique pour constipation avec issue de selle à travers un orifice vulvaire. La radiographie du rachis avait montré une agénésie sacrée. Le fistulo-scanner a mis en évidence une fistule recto-vaginale et l'IRM pelvienne a confirmé l'agénésie sacrée et a retrouvé une méningocèle antérieure. La découverte d'une malformation ano-rectale doit faire chercher une autre anomalie de la triade de Currarino. Cette affection, rare, nécessite une prise en charge médico-chirurgicale assez complexe. PMID:22384297

Visual Depth from Motion Parallax and Eye Pursuit

PubMed Central

Stroyan, Keith; Nawrot, Mark

2012-01-01

A translating observer viewing a rigid environment experiences “motion parallax,” the relative movement upon the observer’s retina of variously positioned objects in the scene. This retinal movement of images provides a cue to the relative depth of objects in the environment, however retinal motion alone cannot mathematically determine relative depth of the objects. Visual perception of depth from lateral observer translation uses both retinal image motion and eye movement. In (Nawrot & Stroyan, 2009, Vision Res. 49, p.1969) we showed mathematically that the ratio of the rate of retinal motion over the rate of smooth eye pursuit mathematically determines depth relative to the fixation point in central vision. We also reported on psychophysical experiments indicating that this ratio is the important quantity for perception. Here we analyze the motion/pursuit cue for the more general, and more complicated, case when objects are distributed across the horizontal viewing plane beyond central vision. We show how the mathematical motion/pursuit cue varies with different points across the plane and with time as an observer translates. If the time varying retinal motion and smooth eye pursuit are the only signals used for this visual process, it is important to know what is mathematically possible to derive about depth and structure. Our analysis shows that the motion/pursuit ratio determines an excellent description of depth and structure in these broader stimulus conditions, provides a detailed quantitative hypothesis of these visual processes for the perception of depth and structure from motion parallax, and provides a computational foundation to analyze the dynamic geometry of future experiments. PMID:21695531

Perception of object motion in three-dimensional space induced by cast shadows.

PubMed

Katsuyama, Narumi; Usui, Nobuo; Nose, Izuru; Taira, Masato

2011-01-01

Cast shadows can be salient depth cues in three-dimensional (3D) vision. Using a motion illusion in which a ball is perceived to roll in depth on the bottom or to flow in the front plane depending on the slope of the trajectory of its cast shadow, we investigated cortical mechanisms underlying 3D vision based on cast shadows using fMRI techniques. When modified versions of the original illusion, in which the slope of the shadow trajectory (shadow slope) was changed in 5 steps from the same one as the ball trajectory to the horizontal, were presented to participants, their perceived ball trajectory shifted gradually from rolling on the bottom to floating in the front plane as the change of the shadow slope. This observation suggests that the perception of the ball trajectory in this illusion is strongly affected by the motion of the cast shadow. In the fMRI study, cortical activity during observation of the movies of the illusion was investigated. We found that the bilateral posterior-occipital sulcus (POS) and right ventral precuneus showed activation related to the perception of the ball trajectory induced by the cast shadows in the illusion. Of these areas, it was suggested that the right POS may be involved in the inferring of the ball trajectory by the given spatial relation between the ball and the shadow. Our present results suggest that the posterior portion of the medial parietal cortex may be involved in 3D vision by cast shadows. Copyright © 2010 Elsevier Inc. All rights reserved.

SOCIETAL COSTS ASSOCIATED WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION IN THE UNITED STATES.

PubMed

Brown, Melissa M; Brown, Gary C; Lieske, Heidi B; Tran, Irwin; Turpcu, Adam; Colman, Shoshana

2016-02-01

The purpose of this study was to use a cross-sectional prevalence-based health care economic survey to ascertain the annual, incremental, societal ophthalmic costs associated with neovascular age-related macular degeneration. Consecutive patients (n = 200) with neovascular age-related macular degeneration were studied. A Control Cohort included patients with good (20/20-20/25) vision, while Study Cohort vision levels included Subcohort 1: 20/30 to 20/50, Subcohort 2: 20/60 to 20/100, Subcohort 3: 20/200 to 20/400, and Subcohort 4: 20/800 to no light perception. An interviewer-administered, standardized, written survey assessed 1) direct ophthalmic medical, 2) direct nonophthalmic medical, 3) direct nonmedical, and 4) indirect medical costs accrued due solely to neovascular age-related macular degeneration. The mean annual societal cost for the Control Cohort was $6,116 and for the Study Cohort averaged $39,910 (P < 0.001). Study Subcohort 1 costs averaged $20,339, while Subcohort 4 costs averaged $82,984. Direct ophthalmic medical costs comprised 17.9% of Study Cohort societal ophthalmic costs, versus 74.1% of Control Cohort societal ophthalmic costs (P < 0.001) and 10.4% of 20/800 to no light perception subcohort costs. Direct nonmedical costs, primarily caregiver, comprised 67.1% of Study Cohort societal ophthalmic costs, versus 21.3% ($1,302/$6,116) of Control Cohort costs (P < 0.001) and 74.1% of 20/800 to no light perception subcohort costs. Total societal ophthalmic costs associated with neovascular age-related macular degeneration dramatically increase as vision in the better-seeing eye decreases.

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

PubMed

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.

What can mice tell us about how vision works?

PubMed Central

Huberman, Andrew D.; Niell, Cristopher M.

2012-01-01

Understanding the neural basis of visual perception is a longstanding fundamental goal of neuroscience. Historically, most vision studies were carried out on humans, macaque monkeys and cats. Over the last five years, however, a growing number of researchers have begun using mice to parse the mechanisms underlying visual processing- the rationale is that despite having relatively poor acuity, mice are unmatched in terms of the variety and sophistication of tools available to label, monitor and manipulate specific cell types and circuits. In this review, we discuss recent advances in understanding the mouse visual system at the anatomical, receptive field and perceptual level, focusing on the opportunities and constraints those features provide toward the goal of understanding how vision works. PMID:21840069

Models of Speed Discrimination

NASA Technical Reports Server (NTRS)

1997-01-01

The prime purpose of this project was to investigate various theoretical issues concerning the integration of information across visual space. To date, most of the research efforts in the study of the visual system seem to have been focused in two almost non-overlaping directions. One research focus has been the low level perception as studied by psychophysics. The other focus has been the study of high level vision exemplified by the study of object perception. Most of the effort in psychophysics has been devoted to the search for the fundamental "features" of perception. The general idea is that the most peripheral processes of the visual system decompose the input into features that are then used for classification and recognition. The experimental and theoretical focus has been on finding and describing these analyzers that decompose images into useful components. Various models are then compared to the physiological measurements performed on neurons in the sensory systems. In the study of higher level perception, the work has been focused on the representation of objects and on the connections between various physical effects and object perception. In this category we find the perception of 3D from a variety of physical measurements including motion, shading and other physical phenomena. With few exceptions, there seem to be very limited development of theories describing how the visual system might combine the output of the analyzers to form the representation of visual objects. Therefore, the processes underlying the integration of information over space represent critical aspects of vision system. The understanding of these processes will have implications on our expectations for the underlying physiological mechanisms, as well as for our models of the internal representation for visual percepts. In this project, we explored several mechanisms related to spatial summation, attention, and eye movements. The project comprised three components: 1. Modeling visual search for the detection of speed deviation. 2. Perception of moving objects. 3. Exploring the role of eye movements in various visual tasks.

Perception of 3-D location based on vision, touch, and extended touch

PubMed Central

Giudice, Nicholas A.; Klatzky, Roberta L.; Bennett, Christopher R.; Loomis, Jack M.

2012-01-01

Perception of the near environment gives rise to spatial images in working memory that continue to represent the spatial layout even after cessation of sensory input. As the observer moves, these spatial images are continuously updated.This research is concerned with (1) whether spatial images of targets are formed when they are sensed using extended touch (i.e., using a probe to extend the reach of the arm) and (2) the accuracy with which such targets are perceived. In Experiment 1, participants perceived the 3-D locations of individual targets from a fixed origin and were then tested with an updating task involving blindfolded walking followed by placement of the hand at the remembered target location. Twenty-four target locations, representing all combinations of two distances, two heights, and six azimuths, were perceived by vision or by blindfolded exploration with the bare hand, a 1-m probe, or a 2-m probe. Systematic errors in azimuth were observed for all targets, reflecting errors in representing the target locations and updating. Overall, updating after visual perception was best, but the quantitative differences between conditions were small. Experiment 2 demonstrated that auditory information signifying contact with the target was not a factor. Overall, the results indicate that 3-D spatial images can be formed of targets sensed by extended touch and that perception by extended touch, even out to 1.75 m, is surprisingly accurate. PMID:23070234

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

PubMed

Yang, Yan-Li; Deng, Hong-Xia; Xing, Gui-Yang; Xia, Xiao-Luan; Li, Hai-Fang

2015-02-01

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.

Protoporphyrin-IX fluorescence guided surgical resection in high-grade gliomas: The potential impact of human colour perception.

PubMed

Petterssen, Max; Eljamel, Sarah; Eljamel, Sam

2014-09-01

Protoporphyrin-IX (Pp-IX) fluorescence had been used frequently in recent years to guide microsurgical resection of high-grade gliomas (HGG), particularly following the publication of a randomized controlled trial demonstrating its advantages. However, Pp-IX fluorescence is dependent upon the surgeons' eyes' perception of red fluorescent colour. This study was designed to evaluate human eye fluorescence perception and establish a fluorescence scale. 20 of 108 pre-recorded images from intraoperative fluorescence of HGG were used to construct an 8-panel visual analogue fluorescence scale. The scale was validated by testing 56 participants with normal colour vision and three red-green colour-blind participants. For intra-rater agreement ten participants were tested twice and for inter-observer reliability the whole cohort were tested. The intra- and inter-observer reliability of the scale in normal colour vision participants was excellent. The scale was less reliable in the violet-blue panels of the scale. Colour-blind participants were not able to distinguish between red fluorescence and blue-violet colours. The 8-panel fluorescence scale is valid in differentiating red, pink and blue colours in a fluorescence surgical field among participants with normal colour perception and potentially useful to standardize fluorescence-guided surgery. However, colourblind surgeons should not use fluorescence-guided surgery. Copyright © 2014 Elsevier B.V. All rights reserved.

Function-based design process for an intelligent ground vehicle vision system

NASA Astrophysics Data System (ADS)

Nagel, Robert L.; Perry, Kenneth L.; Stone, Robert B.; McAdams, Daniel A.

2010-10-01

An engineering design framework for an autonomous ground vehicle vision system is discussed. We present both the conceptual and physical design by following the design process, development and testing of an intelligent ground vehicle vision system constructed for the 2008 Intelligent Ground Vehicle Competition. During conceptual design, the requirements for the vision system are explored via functional and process analysis considering the flows into the vehicle and the transformations of those flows. The conceptual design phase concludes with a vision system design that is modular in both hardware and software and is based on a laser range finder and camera for visual perception. During physical design, prototypes are developed and tested independently, following the modular interfaces identified during conceptual design. Prototype models, once functional, are implemented into the final design. The final vision system design uses a ray-casting algorithm to process camera and laser range finder data and identify potential paths. The ray-casting algorithm is a single thread of the robot's multithreaded application. Other threads control motion, provide feedback, and process sensory data. Once integrated, both hardware and software testing are performed on the robot. We discuss the robot's performance and the lessons learned.

Perceptual training yields rapid improvements in visually impaired youth.

PubMed

Nyquist, Jeffrey B; Lappin, Joseph S; Zhang, Ruyuan; Tadin, Duje

2016-11-30

Visual function demands coordinated responses to information over a wide field of view, involving both central and peripheral vision. Visually impaired individuals often seem to underutilize peripheral vision, even in absence of obvious peripheral deficits. Motivated by perceptual training studies with typically sighted adults, we examined the effectiveness of perceptual training in improving peripheral perception of visually impaired youth. Here, we evaluated the effectiveness of three training regimens: (1) an action video game, (2) a psychophysical task that combined attentional tracking with a spatially and temporally unpredictable motion discrimination task, and (3) a control video game. Training with both the action video game and modified attentional tracking yielded improvements in visual performance. Training effects were generally larger in the far periphery and appear to be stable 12 months after training. These results indicate that peripheral perception might be under-utilized by visually impaired youth and that this underutilization can be improved with only ~8 hours of perceptual training. Moreover, the similarity of improvements following attentional tracking and action video-game training suggest that well-documented effects of action video-game training might be due to the sustained deployment of attention to multiple dynamic targets while concurrently requiring rapid attending and perception of unpredictable events.

Adaptive optics without altering visual perception

PubMed Central

DE, Koenig; NW, Hart; HJ, Hofer

2014-01-01

Adaptive optics combined with visual psychophysics creates the potential to study the relationship between visual function and the retina at the cellular scale. This potential is hampered, however, by visual interference from the wavefront-sensing beacon used during correction. For example, we have previously shown that even a dim, visible beacon can alter stimulus perception (Hofer, H. J., Blaschke, J., Patolia, J., & Koenig, D. E. (2012). Fixation light hue bias revisited: Implications for using adaptive optics to study color vision. Vision Research, 56, 49-56). Here we describe a simple strategy employing a longer wavelength (980nm) beacon that, in conjunction with appropriate restriction on timing and placement, allowed us to perform psychophysics when dark adapted without altering visual perception. The method was verified by comparing detection and color appearance of foveally presented small spot stimuli with and without the wavefront beacon present in 5 subjects. As an important caution, we found that significant perceptual interference can occur even with a subliminal beacon when additional measures are not taken to limit exposure. Consequently, the lack of perceptual interference should be verified for a given system, and not assumed based on invisibility of the beacon. PMID:24607992

The dorsal "action" pathway.

PubMed

Gallivan, Jason P; Goodale, Melvyn A

2018-01-01

In 1992, Goodale and Milner proposed a division of labor in the visual pathways of the primate cerebral cortex. According to their account, the ventral pathway, which projects to occipitotemporal cortex, constructs our visual percepts, while the dorsal pathway, which projects to posterior parietal cortex, mediates the visual control of action. Although the framing of the two-visual-system hypothesis has not been without controversy, it is clear that vision for action and vision for perception have distinct computational requirements, and significant support for the proposed neuroanatomic division has continued to emerge over the last two decades from human neuropsychology, neuroimaging, behavioral psychophysics, and monkey neurophysiology. In this chapter, we review much of this evidence, with a particular focus on recent findings from human neuroimaging and monkey neurophysiology, demonstrating a specialized role for parietal cortex in visually guided behavior. But even though the available evidence suggests that dedicated circuits mediate action and perception, in order to produce adaptive goal-directed behavior there must be a close coupling and seamless integration of information processing across these two systems. We discuss such ventral-dorsal-stream interactions and argue that the two pathways play different, yet complementary, roles in the production of skilled behavior. Copyright © 2018 Elsevier B.V. All rights reserved.

Analyse chronometrique intersexes de la resolution de la tache d'horizontalite des liquides

NASA Astrophysics Data System (ADS)

Berthiaume, Francois

D'abondantes recherches ont demontre que la reussite a la tache d'horizontalite des liquides est en moyenne plus elevee chez les individus de sexe masculin que chez ceux de sexe feminin. Deux facteurs principaux ont ete proposes: il s'agit de la connaissance du principe physique de l'invariance de l'orientation des liquides et de certaines habiletes perceptives d'ordre visuel. Le but de la presente recherche est d'etablir la duree detaillee de la resolution de la tache d'horizontalite des liquides chez 185 filles et 180 garcons, ages de 15 a 19 ans et repartis en 8 groupes. Dans une version informatisee, le premier groupe trace la position de la surface de l'eau a l'interieur d'un contenant dans diverses inclinaisons et le deuxieme evalue si l'orientation d'une ligne y represente bien cette position; le troisieme groupe trace une horizontale dans un rectangle et le quatrieme juge si la ligne illustree y est bien horizontale. Quatre autres groupes executent respectivement les memes taches dans la version classique papier-crayon. Le temps accorde a la reflexion avant de commencer le trace, le temps de tracage comme tel et le temps de verification du trace complete sont calcules. Chez les groupes qui evaluent l'orientation d'une ligne sur support informatique, le temps requis pour y parvenir est note. Enfin, un questionnaire estime si les participants connaissent ou non le principe physique d'invariance de l'orientation de la surface d'un liquide. Les resultats revelent que cette connaissance est plus frequente chez les garcons dans l'ensemble des groupes. Dans le cas ou les sujets ont a tracer une ligne, les filles reussissent moins d'essais que les garcons s'il faut, sur support informatique, tracer la surface de l'eau dans un contenant incline ou a l'horizontale. Il en va de meme s'il faut, sur support papier, tracer une horizontale dans un contenant incline. Le trace de la surface de l'eau est plus exact chez les sujets connaissant le principe d'invariance et l'ecart intersexes disparait si l'analyse tient compte de cette connaissance. Sur le plan du temps de reponse, les deux sexes ne se distinguent que lors du trace de la surface de l'eau dans un contenant incline, les garcons reflechissant alors plus longtemps. Le temps mis a produire, puis a verifier un trace, ne differe pas selon le sexe des participants. Dans l'evaluation de l'orientation d'une ligne cependant, les filles ne se distinguent pas des garcons et les participants connaissant le principe d'invariance reussissent mieux que ceux l'ignorant. Par ailleurs, les filles procedent toujours moins rapidement que les garcons. Pour les contenants inclines ou a l'horizontale, si la ligne represente la surface de l'eau, la difference intersexes est annulee quand la connaissance du principe est prise en compte. (Abstract shortened by UMI.)

Traumatismes Oculaires par Petards: Bilan sur Trois Annees

PubMed Central

Zouaoui-Kesraoui, N.; Derdour, A.

2009-01-01

Summary Les accidents dus aux pétards sont des accidents graves. Leur recrudescence ces dernières années en Algérie, essentiellement durant les fêtes du Mawlid Ennabaoui (fête de la naissance du prophète), mérite à notre sens d'entreprendre des bilans exhaustifs dont celui-ci dans le but d'une sensibilisation de toutes les compétences concernées. Nous avons réuni sur trois années consécutives (2002, 2003, 2004) 60 dossiers de malades ayant subi des accidents oculaires par pétards. Nos patients sont répartis en 42 consultations pour blessures légères et 18 hospitalisations pour blessures graves. Parmi ces derniers, neuf ont présenté des complications et séquelles graves (cinq cas de cécité par atrophie du globe oculaire, trois cas de cécité cornéenne et un cas de cécité par trou maculaire). Dans tous ces cas l'incapacité permanente partielle est au minimum de 30%. Au vu de ces données nous proposons des mesures d'éducation sanitaire et une sensibilisation du grand public aux traumatismes oculaires, par le biais de mé dias appropriés: radio, télévision, affiches. PMID:21991157

Neural dynamics of 3-D surface perception: figure-ground separation and lightness perception.

PubMed

Kelly, F; Grossberg, S

2000-11-01

This article develops the FACADE theory of three-dimensional (3-D) vision to simulate data concerning how two-dimensional pictures give rise to 3-D percepts of occluded and occluding surfaces. The theory suggests how geometrical and contrastive properties of an image can either cooperate or compete when forming the boundary and surface representations that subserve conscious visual percepts. Spatially long-range cooperation and short-range competition work together to separate boundaries of occluding figures from their occluded neighbors, thereby providing sensitivity to T-junctions without the need to assume that T-junction "detectors" exist. Both boundary and surface representations of occluded objects may be amodally completed, whereas the surface representations of unoccluded objects become visible through modal processes. Computer simulations include Bregman-Kanizsa figure-ground separation, Kanizsa stratification, and various lightness percepts, including the Münker-White, Benary cross, and checkerboard percepts.

Cortical visual prostheses: from microstimulation to functional percept

NASA Astrophysics Data System (ADS)

Najarpour Foroushani, Armin; Pack, Christopher C.; Sawan, Mohamad

2018-04-01

Cortical visual prostheses are intended to restore vision by targeted electrical stimulation of the visual cortex. The perception of spots of light, called phosphenes, resulting from microstimulation of the visual pathway, suggests the possibility of creating meaningful percept made of phosphenes. However, to date electrical stimulation of V1 has still not resulted in perception of phosphenated images that goes beyond punctate spots of light. In this review, we summarize the clinical and experimental progress that has been made in generating phosphenes and modulating their associated perceptual characteristics in human and macaque primary visual cortex (V1). We focus specifically on the effects of different microstimulation parameters on perception and we analyse key challenges facing the generation of meaningful artificial percepts. Finally, we propose solutions to these challenges based on the application of supervised learning of population codes for spatial stimulation of visual cortex.

Visual Search in the Real World: Color Vision Deficiency Affects Peripheral Guidance, but Leaves Foveal Verification Largely Unaffected.

PubMed

Kugler, Günter; 't Hart, Bernard M; Kohlbecher, Stefan; Bartl, Klaus; Schumann, Frank; Einhäuser, Wolfgang; Schneider, Erich

2015-01-01

People with color vision deficiencies report numerous limitations in daily life, restricting, for example, their access to some professions. However, they use basic color terms systematically and in a similar manner as people with normal color vision. We hypothesize that a possible explanation for this discrepancy between color perception and behavioral consequences might be found in the gaze behavior of people with color vision deficiency. A group of participants with color vision deficiencies and a control group performed several search tasks in a naturalistic setting on a lawn. All participants wore a mobile eye-tracking-driven camera with a high foveal image resolution (EyeSeeCam). Search performance as well as fixations of objects of different colors were examined. Search performance was similar in both groups in a color-unrelated search task as well as in a search for yellow targets. While searching for red targets, participants with color vision deficiencies exhibited a strongly degraded performance. This was closely matched by the number of fixations on red objects shown by the two groups. Importantly, once they fixated a target, participants with color vision deficiencies exhibited only few identification errors. In contrast to controls, participants with color vision deficiencies are not able to enhance their search for red targets on a (green) lawn by an efficient guiding mechanism. The data indicate that the impaired guiding is the main influence on search performance, while foveal identification (verification) is largely unaffected by the color vision deficiency.

Audiovisual perception in amblyopia: A review and synthesis.

PubMed

Richards, Michael D; Goltz, Herbert C; Wong, Agnes M F

2018-05-17

Amblyopia is a common developmental sensory disorder that has been extensively and systematically investigated as a unisensory visual impairment. However, its effects are increasingly recognized to extend beyond vision to the multisensory domain. Indeed, amblyopia is associated with altered cross-modal interactions in audiovisual temporal perception, audiovisual spatial perception, and audiovisual speech perception. Furthermore, although the visual impairment in amblyopia is typically unilateral, the multisensory abnormalities tend to persist even when viewing with both eyes. Knowledge of the extent and mechanisms of the audiovisual impairments in amblyopia, however, remains in its infancy. This work aims to review our current understanding of audiovisual processing and integration deficits in amblyopia, and considers the possible mechanisms underlying these abnormalities. Copyright © 2018. Published by Elsevier Ltd.

FIRST trial: Lemay park collection plan

DTIC Science & Technology

2007-12-01

expériences : une expé- rience de détection de panache de gaz, une de plastique simulant un panache de gaz, DRDC Valcartier TN 2007-435 i une de...panache de gaz, une de plastique simulant un panache de gaz, une de poudre chimique et une d’artilleries non explosées. Objectifs : Par cet exercice

Neuropsychology: the touchy, feely side of vision.

PubMed

Walsh, V

2000-01-13

Some visual attributes, such as colour, are purely visual, but others, such as orientation and movement, can be perceived by touch or audition. A magnetic stimulation study has now shown that the perception of tactile orientation may be influenced by visual Information.

D. W. Griffith and the Warrior Ethos.

ERIC Educational Resources Information Center

Quart, Leonard; Auster, Al

1989-01-01

Discusses D. W. Griffith's perceptions of war, his idealized vision of the South before and after the Civil War, and his racism as evidenced in the film, "The Birth of a Nation." Considers responses to and effects of the film. (DMM)

Development of Mobile Accessible Pedestrian Signals (MAPS) for Blind Pedestrians at Signalized Intersections

DOT National Transportation Integrated Search

2011-06-01

People with vision impairment have different perception and spatial cognition as compared to the sighted people. Blind pedestrians primarily rely on auditory, olfactory, or tactile feedback to determine spatial location and find their way. They gener...

The Artificial Silicon Retina in Retinitis Pigmentosa Patients (An American Ophthalmological Association Thesis)

PubMed Central

Chow, Alan Y.; Bittner, Ava K.; Pardue, Machelle T.

2010-01-01

Purpose: In a published pilot study, a light-activated microphotodiode-array chip, the artificial silicon retina (ASR), was implanted subretinally in 6 retinitis pigmentosa (RP) patients for up to 18 months. The ASR electrically induced retinal neurotrophic rescue of visual acuity, contrast, and color perception and raised several questions: (1) Would neurotrophic effects develop and persist in additionally implanted RP patients? (2) Could vision in these patients be reliably assessed? (3) Would the ASR be tolerated and function for extended periods? Methods: Four additional RP patients were implanted and observed along with the 6 pilot patients. Of the 10 patients, 6 had vision levels that allowed for more standardized testing and were followed up for 7+ years utilizing ETDRS charts and a 4-alternative forced choice (AFC) Chow grating acuity test (CGAT). A 10-AFC Chow color test (CCT) extended the range of color vision testing. Histologic examination of the eyes of one patient, who died of an unrelated event, was performed. Results: The ASR was well tolerated, and improvement and/or slowing of vision loss occurred in all 6 patients. CGAT extended low vision acuity testing by logMAR 0.6. CCT expanded the range of color vision testing and correlated well with PV-16 (r = 0.77). An ASR recovered from a patient 5 years after implantation showed minor disruption and excellent electrical function. Conclusion: ASR-implanted RP patients experienced prolonged neurotrophic rescue of vision. CGAT and CCT extended the range of acuity and color vision testing in low vision patients. ASR implantation may improve and prolong vision in RP patients. PMID:21212852

Foveal and peripheral fields of vision influences perceptual skill in anticipating opponents' attacking position in volleyball.

PubMed

Schorer, Jörg; Rienhoff, Rebecca; Fischer, Lennart; Baker, Joseph

2013-09-01

The importance of perceptual-cognitive expertise in sport has been repeatedly demonstrated. In this study we examined the role of different sources of visual information (i.e., foveal versus peripheral) in anticipating volleyball attack positions. Expert (n = 11), advanced (n = 13) and novice (n = 16) players completed an anticipation task that involved predicting the location of volleyball attacks. Video clips of volleyball attacks (n = 72) were spatially and temporally occluded to provide varying amounts of information to the participant. In addition, participants viewed the attacks under three visual conditions: full vision, foveal vision only, and peripheral vision only. Analysis of variance revealed significant between group differences in prediction accuracy with higher skilled players performing better than lower skilled players. Additionally, we found significant differences between temporal and spatial occlusion conditions. Both of those factors interacted separately, but not combined with expertise. Importantly, for experts the sum of both fields of vision was superior to either source in isolation. Our results suggest different sources of visual information work collectively to facilitate expert anticipation in time-constrained sports and reinforce the complexity of expert perception.

Emotion-induced trade-offs in spatiotemporal vision.

PubMed

Bocanegra, Bruno R; Zeelenberg, René

2011-05-01

It is generally assumed that emotion facilitates human vision in order to promote adaptive responses to a potential threat in the environment. Surprisingly, we recently found that emotion in some cases impairs the perception of elementary visual features (Bocanegra & Zeelenberg, 2009b). Here, we demonstrate that emotion improves fast temporal vision at the expense of fine-grained spatial vision. We tested participants' threshold resolution with Landolt circles containing a small spatial or brief temporal discontinuity. The prior presentation of a fearful face cue, compared with a neutral face cue, impaired spatial resolution but improved temporal resolution. In addition, we show that these benefits and deficits were triggered selectively by the global configural properties of the faces, which were transmitted only through low spatial frequencies. Critically, the common locus of these opposite effects suggests a trade-off between magno- and parvocellular-type visual channels, which contradicts the common assumption that emotion invariably improves vision. We show that, rather than being a general "boost" for all visual features, affective neural circuits sacrifice the slower processing of small details for a coarser but faster visual signal.

Seeing number using texture: How summary statistics account for reductions in perceived numerosity in the visual periphery.

PubMed

Balas, Benjamin

2016-11-01

Peripheral visual perception is characterized by reduced information about appearance due to constraints on how image structure is represented. Visual crowding is a consequence of excessive integration in the visual periphery. Basic phenomenology of visual crowding and other tasks have been successfully accounted for by a summary-statistic model of pooling, suggesting that texture-like processing is useful for how information is reduced in peripheral vision. I attempt to extend the scope of this model by examining a property of peripheral vision: reduced perceived numerosity in the periphery. I demonstrate that a summary-statistic model of peripheral appearance accounts for reduced numerosity in peripherally viewed arrays of randomly placed dots, but does not account for observed effects of dot clustering within such arrays. The model thus offers a limited account of how numerosity is perceived in the visual periphery. I also demonstrate that the model predicts that numerosity estimation is sensitive to element shape, which represents a novel prediction regarding the phenomenology of peripheral numerosity perception. Finally, I discuss ways to extend the model to a broader range of behavior and the potential for using the model to make further predictions about how number is perceived in untested scenarios in peripheral vision.

Neuro-cognitive mechanisms of conscious and unconscious visual perception: From a plethora of phenomena to general principles

PubMed Central

Kiefer, Markus; Ansorge, Ulrich; Haynes, John-Dylan; Hamker, Fred; Mattler, Uwe; Verleger, Rolf; Niedeggen, Michael

2011-01-01

Psychological and neuroscience approaches have promoted much progress in elucidating the cognitive and neural mechanisms that underlie phenomenal visual awareness during the last decades. In this article, we provide an overview of the latest research investigating important phenomena in conscious and unconscious vision. We identify general principles to characterize conscious and unconscious visual perception, which may serve as important building blocks for a unified model to explain the plethora of findings. We argue that in particular the integration of principles from both conscious and unconscious vision is advantageous and provides critical constraints for developing adequate theoretical models. Based on the principles identified in our review, we outline essential components of a unified model of conscious and unconscious visual perception. We propose that awareness refers to consolidated visual representations, which are accessible to the entire brain and therefore globally available. However, visual awareness not only depends on consolidation within the visual system, but is additionally the result of a post-sensory gating process, which is mediated by higher-level cognitive control mechanisms. We further propose that amplification of visual representations by attentional sensitization is not exclusive to the domain of conscious perception, but also applies to visual stimuli, which remain unconscious. Conscious and unconscious processing modes are highly interdependent with influences in both directions. We therefore argue that exactly this interdependence renders a unified model of conscious and unconscious visual perception valuable. Computational modeling jointly with focused experimental research could lead to a better understanding of the plethora of empirical phenomena in consciousness research. PMID:22253669

Eye movements and attention in reading, scene perception, and visual search.

PubMed

Rayner, Keith

2009-08-01

Eye movements are now widely used to investigate cognitive processes during reading, scene perception, and visual search. In this article, research on the following topics is reviewed with respect to reading: (a) the perceptual span (or span of effective vision), (b) preview benefit, (c) eye movement control, and (d) models of eye movements. Related issues with respect to eye movements during scene perception and visual search are also reviewed. It is argued that research on eye movements during reading has been somewhat advanced over research on eye movements in scene perception and visual search and that some of the paradigms developed to study reading should be more widely adopted in the study of scene perception and visual search. Research dealing with "real-world" tasks and research utilizing the visual-world paradigm are also briefly discussed.

Comparative analysis of visual outcomes with 4 intraocular lenses: Monofocal, multifocal, and extended range of vision.

PubMed

Pedrotti, Emilio; Carones, Francesco; Aiello, Francesco; Mastropasqua, Rodolfo; Bruni, Enrico; Bonacci, Erika; Talli, Pietro; Nucci, Carlo; Mariotti, Cesare; Marchini, Giorgio

2018-02-01

To compare the visual acuity, refractive outcomes, and quality of vision in patients with bilateral implantation of 4 intraocular lenses (IOLs). Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, University of Verona, Verona, and Carones Ophthalmology Center, Milano, Italy. Prospective case series. The study included patients who had bilateral cataract surgery with the implantation of 1 of 4 IOLs as follows: Tecnis 1-piece monofocal (monofocal IOL), Tecnis Symfony extended range of vision (extended-range-of-vision IOL), Restor +2.5 diopter (D) (+2.5 D multifocal IOL), and Restor +3.0 D (+3.0 D multifocal IOL). Visual acuity, refractive outcome, defocus curve, objective optical quality, contrast sensitivity, spectacle independence, and glare perception were evaluated 6 months after surgery. The study comprised 185 patients. The extended-range-of-vision IOL (55 patients) showed better distance visual outcomes than the monofocal IOL (30 patients) and high-addition apodized diffractive-refractive multifocal IOLs (P ≤ .002). The +3.0 D multifocal IOL (50 patients) showed the best near visual outcomes (P < .001). The +2.5 D multifocal IOL (50 patients) and extended-range-of-vision IOL provided significantly better intermediate visual outcomes than the other 2 IOLs, with significantly better vision for a defocus level of -1.5 D (P < .001). Better spectacle independence was shown for the +2.5 D multifocal IOL and extended-range-of-vision IOL (P < .001). The extended-range-of-vision IOL and +2.5 D multifocal IOL provided significantly better intermediate visual restoration after cataract surgery than the monofocal IOL and +3.0 D multifocal IOL, with significantly better quality of vision with the extended-range-of-vision IOL. Copyright © 2018 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

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

PubMed Central

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

2014-01-01

Background Research groups and funding agencies need a functional assessment suitable for an ultra-low vision population in order to evaluate the impact of new vision restoration treatments. The purpose of this study was to develop a pilot assessment to capture the functional vision ability and well-being of subjects whose vision has been partially restored with the Argus II Retinal Prosthesis System. Methods The Functional Low-Vision Observer Rated Assessment (FLORA) pilot assessment involved a self-report section, a list of functional vision tasks for observation of performance, and a case narrative summary. Results were analyzed to determine whether the interview questions and functional vision 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, twenty-six subjects were assessed with the FLORA. Seven different evaluators administered the assessment. Results All 14 interview questions were asked. All 35 functional vision tasks 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%), difficult (23%), moderate (24%) and easy (19%) -- 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% on average with the System ON, and 29% with the System OFF. Conclusion 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 a functional vision and well-being assessment tool. PMID:25675964

Parametric Study of Diffusion-Enhancement Networks for Spatiotemporal Grouping in Real-Time Artificial Vision

DTIC Science & Technology

1993-04-01

suggesting it occurs in later visual motion processing (long-range or second-order system). STIMULUS PERCEPT L" FLASH DURATION FLASH DURATION (a) TIME ( b ...TIME Figure 2. Gamma motion. (a) A light of fixed spatial extent is illuminated then extim- guished. ( b ) The percept is of a light expanding and then...while smaller, type- B cells provide input to its parvocellular subdivision. From here the magnocellular pathway progresses up through visual cortex area V

Using brain stimulation to disentangle neural correlates of conscious vision

PubMed Central

de Graaf, Tom A.; Sack, Alexander T.

2014-01-01

Research into the neural correlates of consciousness (NCCs) has blossomed, due to the advent of new and increasingly sophisticated brain research tools. Neuroimaging has uncovered a variety of brain processes that relate to conscious perception, obtained in a range of experimental paradigms. But methods such as functional magnetic resonance imaging or electroencephalography do not always afford inference on the functional role these brain processes play in conscious vision. Such empirical NCCs could reflect neural prerequisites, neural consequences, or neural substrates of a conscious experience. Here, we take a closer look at the use of non-invasive brain stimulation (NIBS) techniques in this context. We discuss and review how NIBS methodology can enlighten our understanding of brain mechanisms underlying conscious vision by disentangling the empirical NCCs. PMID:25295015

Approche à l’égard des nouveaux anticoagulants oraux en pratique familiale

PubMed Central

Douketis, James; Bell, Alan David; Eikelboom, John; Liew, Aaron

2014-01-01

Résumé Objectif Traiter des différentes éventualités pouvant survenir durant le suivi clinique et la prise en charge prolongés des patients prenant de nouveaux anticoagulants oraux (NACO). Qualité des données Aux fins de cette révision narrative (non systématique), nous avons effectué une recherche dans la base de données PubMed afin de relever des études cliniques récentes (soit de janvier 2008 à la semaine 32 de 2013) portant sur l’emploi des NACO pour la prévention des AVC dans les cas de fibrillation auriculaire et le traitement de la thromboembolie veineuse aiguë. Nous avons utilisé cette base de données probantes pour répondre à nos questions prédéfinies ayant trait à l’emploi des NACO en pratique générale. Message principal Le dabigatran et le rivaroxaban doivent être pris avec les repas afin de limiter la dyspepsie et de favoriser l’absorption, respectivement. Aucun NACO n’est accompagné de restrictions alimentaires, à l’exception de la consommation modérée d’alcool, et le rivaroxaban et l’apixaban peuvent être écrasés, au besoin. Les antiacides ne semblent pas perturber l’efficacité des NACO. Comme c’est le cas avec la warfarine, les patients traités aux NACO doivent éviter l’emploi prolongé d’anti-inflammatoires non stéroïdiens et d’antiplaquettaires. Chez les patients devant subir une chirurgie, il faut interrompre la prise de NACO de 2 à 5 jours avant l’intervention, en fonction du risque de saignement, et le traitement par le NACO doit être habituellement repris au moins 24 heures après la chirurgie. Il n’est habituellement pas nécessaire d’effectuer un test préopératoire de coagulation. Chez les patients qui développent un saignement, un saignement mineur ne justifie habituellement pas un test de laboratoire ni l’interruption du traitement par le NACO; dans le cas des saignements majeurs, il faut se concentrer sur l’application de mesures localisées visant à endiguer le saignement et sur les soins infirmiers et il y a aussi lieu de procéder à un test de coagulation. Il n’existe à l’heure actuelle aucun antidote pour renverser les effets des NACO. Ces derniers ne doivent pas être administrés aux patients porteurs d’une valvule cardiaque mécanique ou qui sont atteints d’une maladie valvulaire cardiaque, d’une thrombose veineuse profonde liée au cancer ou d’une thrombophlébite superficielle. Conclusion La prise en charge des scénarios éventuels chez les patients qui prennent des NACO a été proposée, mais plus d’études sur ces questions sont nécessaires, particulièrement sur la prise en charge peropératoire et les saignements.

People with dyslexia and heart, chest, skin, digestive, musculoskeletal, vision, learning, speech and mental disorders were more dissatisfied with neighbourhoods: Scottish Household Survey, 2007-2008.

PubMed

Shiue, Ivy

2016-12-01

Rarely do we know the perception toward neighbourhoods in people specifically with health conditions. Therefore, the aim of the present study was to understand the perception toward neighbourhoods among adults with a series of the existing health conditions in a country-wide and population-based setting. Data were retrieved from and analysed in Scottish Household Survey, 2007-2008. Information on demographics, self-reported health conditions and perception toward neighbourhoods and the surrounding facilities was obtained by household interview. Analysis including chi-square test, t test and logistic regression modelling were performed. Of 19,150 Scottish adults (aged 16-80) included in the study cohort, 1079 (7.7 %) people were dissatisfied with their living areas; particularly for those who experienced harassment (15.4 %), did not recycle or with dyslexia, chest, digestive, mental and musculoskeletal problems. Twenty to forty per cent reported common neighbourhood problems including noise, rubbish, disputes, graffiti, harassment and drug misuse. People with heart or digestive problems were more dissatisfied with the existing parks and open space. People with arthritis, chest or hearing problems were more dissatisfied with the waste management condition. People with dyslexia were more dissatisfied with the existing public transportation. People with heart problems were more dissatisfied with the current street cleaning condition. People with hearing, vision, speech, learning problems or dyslexia were also more dissatisfied with sports and recreational facilities. People with heart, chest, skin, digestive, musculoskeletal, vision, learning, speech and mental disorders and dyslexia were more dissatisfied with their current neighbourhood environments. Upgrading neighbourhood planning to tackle social environment injustice and put pleasant life experience as priorty would be suggested. Graphical abstract interrelations of individual health and neighbourhood health.

Proprioceptive loss and the perception, control and learning of arm movements in humans: evidence from sensory neuronopathy.

PubMed

Miall, R Chris; Kitchen, Nick M; Nam, Se-Ho; Lefumat, Hannah; Renault, Alix G; Ørstavik, Kristin; Cole, Jonathan D; Sarlegna, Fabrice R

2018-05-19

It is uncertain how vision and proprioception contribute to adaptation of voluntary arm movements. In normal participants, adaptation to imposed forces is possible with or without vision, suggesting that proprioception is sufficient; in participants with proprioceptive loss (PL), adaptation is possible with visual feedback, suggesting that proprioception is unnecessary. In experiment 1 adaptation to, and retention of, perturbing forces were evaluated in three chronically deafferented participants. They made rapid reaching movements to move a cursor toward a visual target, and a planar robot arm applied orthogonal velocity-dependent forces. Trial-by-trial error correction was observed in all participants. Such adaptation has been characterized with a dual-rate model: a fast process that learns quickly, but retains poorly and a slow process that learns slowly and retains well. Experiment 2 showed that the PL participants had large individual differences in learning and retention rates compared to normal controls. Experiment 3 tested participants' perception of applied forces. With visual feedback, the PL participants could report the perturbation's direction as well as controls; without visual feedback, thresholds were elevated. Experiment 4 showed, in healthy participants, that force direction could be estimated from head motion, at levels close to the no-vision threshold for the PL participants. Our results show that proprioceptive loss influences perception, motor control and adaptation but that proprioception from the moving limb is not essential for adaptation to, or detection of, force fields. The differences in learning and retention seen between the three deafferented participants suggest that they achieve these tasks in idiosyncratic ways after proprioceptive loss, possibly integrating visual and vestibular information with individual cognitive strategies.

Functional vision and cognition in infants with congenital disorders of the peripheral visual system.

PubMed

Dale, Naomi; Sakkalou, Elena; O'Reilly, Michelle; Springall, Clare; De Haan, Michelle; Salt, Alison

2017-07-01

To investigate how vision relates to early development by studying vision and cognition in a national cohort of 1-year-old infants with congenital disorders of the peripheral visual system and visual impairment. This was a cross-sectional observational investigation of a nationally recruited cohort of infants with 'simple' and 'complex' congenital disorders of the peripheral visual system. Entry age was 8 to 16 months. Vision level (Near Detection Scale) and non-verbal cognition (sensorimotor understanding, Reynell Zinkin Scales) were assessed. Parents completed demographic questionnaires. Of 90 infants (49 males, 41 females; mean 13mo, standard deviation [SD] 2.5mo; range 7-17mo); 25 (28%) had profound visual impairment (light perception at best) and 65 (72%) had severe visual impairment (basic 'form' vision). The Near Detection Scale correlated significantly with sensorimotor understanding developmental quotients in the 'total', 'simple', and 'complex' groups (all p<0.001). Age and vision accounted for 48% of sensorimotor understanding variance. Infants with profound visual impairment, especially in the 'complex' group with congenital disorders of the peripheral visual system with known brain involvement, showed the greatest cognitive delay. Lack of vision is associated with delayed early-object manipulative abilities and concepts; 'form' vision appeared to support early developmental advance. This paper provides baseline characteristics for cross-sectional and longitudinal follow-up investigations in progress. A methodological strength of the study was the representativeness of the cohort according to national epidemiological and population census data. © 2017 Mac Keith Press.

Acute optic neuritis

PubMed Central

Galetta, Steven L.; Villoslada, Pablo; Levin, Netta; Shindler, Kenneth; Ishikawa, Hiroshi; Parr, Edward; Cadavid, Diego

2015-01-01

Idiopathic demyelinating optic neuritis (ON) most commonly presents as acute unilateral vision loss and eye pain and is frequently associated with multiple sclerosis. Although emphasis is often placed on the good recovery of high-contrast visual acuity, persistent deficits are frequently observed in other aspects of vision, including contrast sensitivity, visual field testing, color vision, motion perception, and vision-related quality of life. Persistent and profound structural and functional changes are often revealed by imaging and electrophysiologic techniques, including optical coherence tomography, visual-evoked potentials, and nonconventional MRI. These abnormalities can impair patients' abilities to perform daily activities (e.g., driving, working) so they have important implications for patients' quality of life. In this article, we review the sequelae from ON, including clinical, structural, and functional changes and their interrelationships. The unmet needs in each of these areas are considered and the progress made toward meeting those needs is examined. Finally, we provide an overview of past and present investigational approaches for disease modification in ON. PMID:26236761

Le syndrome d’Usher: à propos d’une observation

PubMed Central

Daoudi, Chama; boutimzine, Noureddine; Haouzi, Samia El; Lezrek, Omar; Tachfouti, Samira; Lezrek, Mounir; Laghmari, Mina; Daoudi, Rajae

2017-01-01

Résumé Le syndrome d'Usher est une maladie génétique comportant une double atteinte sensorielle (auditive et visuelle) appelée surdicécité. Nous rapportons l'observation d'un patient de 50 ans, issue d'un mariage consanguin présentant une surdité congénitale avec une fonction vestibulaire normale et une rétinopathie pigmentaire responsable d'une baisse bilatérale de l'acuité visuelle apparue vers l'âge de 16 ans. Cette association compose le type 2 du syndrome d'Usher, affection rare de transmission autosomique récessive. La chirurgie de la cataracte a permis une amélioration de l'acuité visuelle chez ce patient. PMID:28979619

Visual Search in the Real World: Color Vision Deficiency Affects Peripheral Guidance, but Leaves Foveal Verification Largely Unaffected

PubMed Central

Kugler, Günter; 't Hart, Bernard M.; Kohlbecher, Stefan; Bartl, Klaus; Schumann, Frank; Einhäuser, Wolfgang; Schneider, Erich

2015-01-01

Background: People with color vision deficiencies report numerous limitations in daily life, restricting, for example, their access to some professions. However, they use basic color terms systematically and in a similar manner as people with normal color vision. We hypothesize that a possible explanation for this discrepancy between color perception and behavioral consequences might be found in the gaze behavior of people with color vision deficiency. Methods: A group of participants with color vision deficiencies and a control group performed several search tasks in a naturalistic setting on a lawn. All participants wore a mobile eye-tracking-driven camera with a high foveal image resolution (EyeSeeCam). Search performance as well as fixations of objects of different colors were examined. Results: Search performance was similar in both groups in a color-unrelated search task as well as in a search for yellow targets. While searching for red targets, participants with color vision deficiencies exhibited a strongly degraded performance. This was closely matched by the number of fixations on red objects shown by the two groups. Importantly, once they fixated a target, participants with color vision deficiencies exhibited only few identification errors. Conclusions: In contrast to controls, participants with color vision deficiencies are not able to enhance their search for red targets on a (green) lawn by an efficient guiding mechanism. The data indicate that the impaired guiding is the main influence on search performance, while foveal identification (verification) is largely unaffected by the color vision deficiency. PMID:26733851

Dense range map reconstruction from a versatile robotic sensor system with an active trinocular vision and a passive binocular vision.

PubMed

Kim, Min Young; Lee, Hyunkee; Cho, Hyungsuck

2008-04-10

One major research issue associated with 3D perception by robotic systems is the creation of efficient sensor systems that can generate dense range maps reliably. A visual sensor system for robotic applications is developed that is inherently equipped with two types of sensor, an active trinocular vision and a passive stereo vision. Unlike in conventional active vision systems that use a large number of images with variations of projected patterns for dense range map acquisition or from conventional passive vision systems that work well on specific environments with sufficient feature information, a cooperative bidirectional sensor fusion method for this visual sensor system enables us to acquire a reliable dense range map using active and passive information simultaneously. The fusion algorithms are composed of two parts, one in which the passive stereo vision helps active vision and the other in which the active trinocular vision helps the passive one. The first part matches the laser patterns in stereo laser images with the help of intensity images; the second part utilizes an information fusion technique using the dynamic programming method in which image regions between laser patterns are matched pixel-by-pixel with help of the fusion results obtained in the first part. To determine how the proposed sensor system and fusion algorithms can work in real applications, the sensor system is implemented on a robotic system, and the proposed algorithms are applied. A series of experimental tests is performed for a variety of configurations of robot and environments. The performance of the sensor system is discussed in detail.

Colour Vision: Understanding #TheDress.

PubMed

Brainard, David H; Hurlbert, Anya C

2015-06-29

A widely-viewed image of a dress elicits striking individual variation in colour perception. Experiments with multiple variants of the image suggest that the individual differences may arise through the action of visual mechanisms that normally stabilise object colour. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hypermediated Art Criticism

ERIC Educational Resources Information Center

Taylor, Pamela G.; Carpenter, B. Stephen, II

2007-01-01

Technological media catapults our perception into what Marshall McLuhan called "new transforming vision and awareness." As our lives become more and more immersed in such technologies as television, film, and interactive computers, we find ourselves inundated with a heightened sense of mindfulness--an aesthetic experience made possible through…

Materials science challenges in paintings

NASA Astrophysics Data System (ADS)

Walter, Philippe; de Viguerie, Laurence

2018-02-01

Through the paintings of the old masters, we showcase how materials science today provides us with a vision of the processes involved in the creation of a work of art: the choice of materials, the painter's skill in handling these materials, and the perception of the finished work.

Materials science challenges in paintings.

PubMed

Walter, Philippe; de Viguerie, Laurence

2018-01-23

Through the paintings of the old masters, we showcase how materials science today provides us with a vision of the processes involved in the creation of a work of art: the choice of materials, the painter's skill in handling these materials, and the perception of the finished work.

The Relationship between Visual Impairment and Health-Related Quality of Life in Korean Adults: The Korea National Health and Nutrition Examination Survey (2008–2012)

PubMed Central

Park, Yuli; Shin, Jeong Ah; Yang, Suk Woo; Yim, Hyeon Woo; Kim, Hyun Seung; Park, Young-Hoon

2015-01-01

Introduction To evaluate health-related quality of life (HRQoL) in Korean adults with visual impairment(VI) using various measures based on a nationally distributed sample. Methods Using the Korea National Health and Nutrition Examination Survey (KNHANES, 2008–2012) data, we compared EuroQol five-dimensional questionnaire (EQ-5D) and EQ-visual analogue scale (VAS) scores after adjusting for socio-demographic and psychosocial factors as well as for comorbidities with VI. Logistic regressions were used to elucidate determinants for the lowest quintile HRQoL scales according to VI severity. Uncorrected visual acuity (VA) which implies vision of ordinary life was measured using an international standard vision chart based on Snellen scale. Results 28,825 participants (sum of weights; 37,562,376) were included in the analysis. The mean EQ-5D and EQ-VAS scores were significantly lower in the VI groups than in the normal vision (defined as VA 20/20-20/25) group based on the better or worse seeing eye (P<.0001 and P<.0001, respectively). Participants with moderate (VA 20/80-20/160) and severe VI (VA ≤20/200) had higher scores of multivariate-adjusted odd ratios (aORs) for the lowest quintile than did the normal vision group which was particularly evident in the results from EQ-5D, whereas the results of the mild VI (VA 20/32-20/63) group did not identify significant differences from the normal vision group independent of classification according to the better or the worse seeing eye. Conversely, EQ-VAS revealed significantly higher score of multivariate-aORs for the lowest quintile in participants with mild VI either for the better or worse seeing eye. Conclusions The severity of VI was definitely associated with impaired HRQoL compared with the normal vision population. The analyses presented here elicited even mild VI could potentially deteriorate the health-related quality of life (or subjective perception of health quality) and therefore, therapeutic approaches should also focus on the subjective perception and better management of health condition. PMID:26192763

The Ontology of Vision. The Invisible, Consciousness of Living Matter

PubMed Central

Fiorio, Giorgia

2016-01-01

If I close my eyes, the absence of light activates the peripheral cells devoted to the perception of darkness. The awareness of “seeing oneself seeing” is in its essence a thought, one that is internal to the vision and previous to any object of sight. To this amphibious faculty, the “diaphanous color of darkness,” Aristotle assigns the principle of knowledge. “Vision is a whole perceptual system, not a channel of sense.” Functions of vision are interwoven with the texture of human interaction within a terrestrial environment that is in turn contained into the cosmic order. A transitive host within the resonance of an inner-outer environment, the human being is the contact-term between two orders of scale, both bigger and smaller than the individual unity. In the perceptual integrative system of human vision, the convergence-divergence of the corporeal presence and the diffraction of its own appearance is the margin. The sensation of being no longer coincides with the breath of life, it does not seems “real” without the trace of some visible evidence and its simultaneous “sharing”. Without a shadow, without an imprint, the numeric copia of the physical presence inhabits the transient memory of our electronic prostheses. A rudimentary “visuality” replaces tangible experience dissipating its meaning and the awareness of being alive. Transversal to the civilizations of the ancient world, through different orders of function and status, the anthropomorphic “figuration” of archaic sculpture addressees the margin between Being and Non-Being. Statuary human archetypes are not meant to be visible, but to exist as vehicles of transcendence to outlive the definition of human space-time. The awareness of individual finiteness seals the compulsion to “give body” to an invisible apparition shaping the figuration of an ontogenetic expression of human consciousness. Subject and object, the term “humanum” fathoms the relationship between matter and its living dimension, “this de facto vision and the ‘there is’ which it contains.” The project reconsiders the dialectic between the terms vision–presence in the contemporary perception of archaic human statuary according to the transcendent meaning of its immaterial legacy. PMID:27014106

The contribution of single case studies to the neuroscience of vision.

PubMed

Zihl, Josef; Heywood, Charles A

2016-03-01

Visual neuroscience is concerned with the neurobiological foundations of visual perception, that is, the morphological, physiological, and functional organization of the visual brain and its co-operative partners. One important approach for understanding the functional organization of the visual brain is the study of visual perception from the pathological perspective. The study of patients with focal injury to the visual brain allows conclusions about the representation of visual perceptual functions in the framework of association and dissociation of functions. Selective disorders have been reported for more "elementary" visual capabilities, for example, color and movement vision, but also for visuo-cognitive capacities, such as visual agnosia or the visual field of attention. Because these visual disorders occur rather seldom as selective and specific dysfunctions, single cases have always played, and still play, a significant role in gaining insights into the functional organization of the visual brain. © 2016 The Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

The role of spatial integration in the perception of surface orientation with active touch.

PubMed

Giachritsis, Christos D; Wing, Alan M; Lovell, Paul G

2009-10-01

Vision research has shown that perception of line orientation, in the fovea area, improves with line length (Westheimer & Ley, 1997). This suggests that the visual system may use spatial integration to improve perception of orientation. In the present experiments, we investigated the role of spatial integration in the perception of surface orientation using kinesthetic and proprioceptive information from shoulder and elbow. With their left index fingers, participants actively explored virtual slanted surfaces of different lengths and orientations, and were asked to reproduce an orientation or discriminate between two orientations. Results showed that reproduction errors and discrimination thresholds improve with surface length. This suggests that the proprioceptive shoulder-elbow system may integrate redundant spatial information resulting from extended arm movements to improve orientation judgments.

Functional vision loss: a diagnosis of exclusion.

PubMed

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.

Coevolution of coloration and colour vision?

PubMed

Lind, Olle; Henze, Miriam J; Kelber, Almut; Osorio, Daniel

2017-07-05

The evolutionary relationship between signals and animal senses has broad significance, with potential consequences for speciation, and for the efficacy and honesty of biological communication. Here we outline current understanding of the diversity of colour vision in two contrasting groups: the phylogenetically conservative birds, and the more variable butterflies. Evidence for coevolution of colour signals and vision exists in both groups, but is limited to observations of phenotypic differences between visual systems, which might be correlated with coloration. Here, to illustrate how one might interpret the evolutionary significance of such differences, we used colour vision modelling based on an avian eye to evaluate the effects of variation in three key characters: photoreceptor spectral sensitivity, oil droplet pigmentation and the proportions of different photoreceptor types. The models predict that physiologically realistic changes in any one character will have little effect, but complementary shifts in all three can substantially affect discriminability of three types of natural spectra. These observations about the adaptive landscape of colour vision may help to explain the general conservatism of photoreceptor spectral sensitivities in birds. This approach can be extended to other types of eye and spectra to inform future work on coevolution of coloration and colour vision.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Author(s).

[Colors and their meaning in culture and psychology--a historical outline and contemporary status of color vision theories].

PubMed

Grzybowski, Andrzej; Lewicka, Romana; Torlińska, Teresa; Stelcer, Bogusław

2008-01-01

The mechanism of color perception has intrigued scholars from antiquity. However, the understanding of this phenomena only came with the recognition of the nature of light and visual perception. Ancient concepts, present in science until the Renaissance, were based more on philosophical considerations and theoretical speculations than on anatomical studies and a matter-of-fact assessment of physiological functions of the visual system. From antiquity to 17th century scientific approach to the concept of vision was dominated by two theories: intromission and extramission (emanation). Intromission theory, propagated by Alhazen (lbn al.-Haythama), Vitello, John Peckham, Roger Bacon and Leonardo da Vinci, assumed that the light was transmitted from the observed object perpendicularly to the transparent eye structures. Johannes Kepler was the first scholar to propose that the retina was the receptive part of the eye. In the first half of the 17th century, Kepler's groundbreaking optical achievements and anatomical discoveries of many other scientists cast new light on the understanding of the role of different eye structures, finally wiping out the intromission theory. A further major achievement contributing to the recognition of the true nature of colors was a theory presented by Newton in 1688. He argued that they were colored rays, and not white light, that were composed of homogenous and pure light. It was, however, not until the 19th century when two modern theories of color appeared, i.e. a trichromatic theory mostly associated with the names of Young and Hemlholtz, and an opponent colors theory of Hering. In the 20th century, the two theories--previously assumed as contradictory--were joined into the zone theories of color vision. Colors have their cultural and social meanings, as far as a very individual and personal interpretation. In the former function they are used to illustrate some cultural and sociological phenomena; in the latter, they are helpful in psychological analyses of patients. The paper outlines major historical concepts of color perception and the present usefulness of color vision tests in psychology.

Adaptive Feedback in Local Coordinates for Real-time Vision-Based Motion Control Over Long Distances

NASA Astrophysics Data System (ADS)

Aref, M. M.; Astola, P.; Vihonen, J.; Tabus, I.; Ghabcheloo, R.; Mattila, J.

2018-03-01

We studied the differences in noise-effects, depth-correlated behavior of sensors, and errors caused by mapping between coordinate systems in robotic applications of machine vision. In particular, the highly range-dependent noise densities for semi-unknown object detection were considered. An equation is proposed to adapt estimation rules to dramatic changes of noise over longer distances. This algorithm also benefits the smooth feedback of wheels to overcome variable latencies of visual perception feedback. Experimental evaluation of the integrated system is presented with/without the algorithm to highlight its effectiveness.

When science meets capitalism

NASA Astrophysics Data System (ADS)

Parker, Greg

2008-03-01

When I joined the University of Southampton's microelectronics group in 1987 after spending 10 years in industry, I shared some of my commercial ideas for advancing the group into the 21st century with my academic colleagues. To say that my personal vision of paradise was close to their vision of hell is probably a pretty accurate observation. Two decades on, I now understand why they felt that way. Science for Sale contains a lot of information that explains this vast difference in perception, and the book also does a good job of highlighting how academia and industry differ on practical and ethical levels.

Spatial and temporal characteristics of V1 microstimulation during chronic implantation of a microelectrode array in a behaving macaque

NASA Astrophysics Data System (ADS)

Davis, T. S.; Parker, R. A.; House, P. A.; Bagley, E.; Wendelken, S.; Normann, R. A.; Greger, B.

2012-12-01

Objective. It has been hypothesized that a vision prosthesis capable of evoking useful visual percepts can be based upon electrically stimulating the primary visual cortex (V1) of a blind human subject via penetrating microelectrode arrays. As a continuation of earlier work, we examined several spatial and temporal characteristics of V1 microstimulation. Approach. An array of 100 penetrating microelectrodes was chronically implanted in V1 of a behaving macaque monkey. Microstimulation thresholds were measured using a two-alternative forced choice detection task. Relative locations of electrically-evoked percepts were measured using a memory saccade-to-target task. Main results. The principal finding was that two years after implantation we were able to evoke behavioural responses to electric stimulation across the spatial extent of the array using groups of contiguous electrodes. Consistent responses to stimulation were evoked at an average threshold current per electrode of 204 ± 49 µA (mean ± std) for groups of four electrodes and 91 ± 25 µA for groups of nine electrodes. Saccades to electrically-evoked percepts using groups of nine electrodes showed that the animal could discriminate spatially distinct percepts with groups having an average separation of 1.6 ± 0.3 mm (mean ± std) in cortex and 1.0° ± 0.2° in visual space. Significance. These results demonstrate chronic perceptual functionality and provide evidence for the feasibility of a cortically-based vision prosthesis for the blind using penetrating microelectrodes.

Auditory-visual fusion in speech perception in children with cochlear implants

PubMed Central

Schorr, Efrat A.; Fox, Nathan A.; van Wassenhove, Virginie; Knudsen, Eric I.

2005-01-01

Speech, for most of us, is a bimodal percept whenever we both hear the voice and see the lip movements of a speaker. Children who are born deaf never have this bimodal experience. We tested children who had been deaf from birth and who subsequently received cochlear implants for their ability to fuse the auditory information provided by their implants with visual information about lip movements for speech perception. For most of the children with implants (92%), perception was dominated by vision when visual and auditory speech information conflicted. For some, bimodal fusion was strong and consistent, demonstrating a remarkable plasticity in their ability to form auditory-visual associations despite the atypical stimulation provided by implants. The likelihood of consistent auditory-visual fusion declined with age at implant beyond 2.5 years, suggesting a sensitive period for bimodal integration in speech perception. PMID:16339316

When visual perception causes feeling: enhanced cross-modal processing in grapheme-color synesthesia.

PubMed

Weiss, Peter H; Zilles, Karl; Fink, Gereon R

2005-12-01

In synesthesia, stimulation of one sensory modality (e.g., hearing) triggers a percept in another, non-stimulated sensory modality (e.g., vision). Likewise, perception of a form (e.g., a letter) may induce a color percept (i.e., grapheme-color synesthesia). To date, the neural mechanisms underlying synesthesia remain to be elucidated. We disclosed by fMRI, while controlling for surface color processing, enhanced activity in the left intraparietal cortex during the experience of grapheme-color synesthesia (n = 9). In contrast, the perception of surface color per se activated the color centers in the fusiform gyrus bilaterally. The data support theoretical accounts that grapheme-color synesthesia may originate from enhanced cross-modal binding of form and color. A mismatch of surface color and grapheme induced synesthetically felt color additionally activated the left dorsolateral prefrontal cortex (DLPFC). This suggests that cognitive control processes become active to resolve the perceptual conflict resulting from synesthesia.

Binocular combination in abnormal binocular vision

PubMed Central

Ding, Jian; Klein, Stanley A.; Levi, Dennis M.

2013-01-01

We investigated suprathreshold binocular combination in humans with abnormal binocular visual experience early in life. In the first experiment we presented the two eyes with equal but opposite phase shifted sine waves and measured the perceived phase of the cyclopean sine wave. Normal observers have balanced vision between the two eyes when the two eyes' images have equal contrast (i.e., both eyes contribute equally to the perceived image and perceived phase = 0°). However, in observers with strabismus and/or amblyopia, balanced vision requires a higher contrast image in the nondominant eye (NDE) than the dominant eye (DE). This asymmetry between the two eyes is larger than predicted from the contrast sensitivities or monocular perceived contrast of the two eyes and is dependent on contrast and spatial frequency: more asymmetric with higher contrast and/or spatial frequency. Our results also revealed a surprising NDE-to-DE enhancement in some of our abnormal observers. This enhancement is not evident in normal vision because it is normally masked by interocular suppression. However, in these abnormal observers the NDE-to-DE suppression was weak or absent. In the second experiment, we used the identical stimuli to measure the perceived contrast of a cyclopean grating by matching the binocular combined contrast to a standard contrast presented to the DE. These measures provide strong constraints for model fitting. We found asymmetric interocular interactions in binocular contrast perception, which was dependent on both contrast and spatial frequency in the same way as in phase perception. By introducing asymmetric parameters to the modified Ding-Sperling model including interocular contrast gain enhancement, we succeeded in accounting for both binocular combined phase and contrast simultaneously. Adding binocular contrast gain control to the modified Ding-Sperling model enabled us to predict the results of dichoptic and binocular contrast discrimination experiments and provides new insights into the mechanisms of abnormal binocular vision. PMID:23397039

Binocular combination in abnormal binocular vision.

PubMed

Ding, Jian; Klein, Stanley A; Levi, Dennis M

2013-02-08

We investigated suprathreshold binocular combination in humans with abnormal binocular visual experience early in life. In the first experiment we presented the two eyes with equal but opposite phase shifted sine waves and measured the perceived phase of the cyclopean sine wave. Normal observers have balanced vision between the two eyes when the two eyes' images have equal contrast (i.e., both eyes contribute equally to the perceived image and perceived phase = 0°). However, in observers with strabismus and/or amblyopia, balanced vision requires a higher contrast image in the nondominant eye (NDE) than the dominant eye (DE). This asymmetry between the two eyes is larger than predicted from the contrast sensitivities or monocular perceived contrast of the two eyes and is dependent on contrast and spatial frequency: more asymmetric with higher contrast and/or spatial frequency. Our results also revealed a surprising NDE-to-DE enhancement in some of our abnormal observers. This enhancement is not evident in normal vision because it is normally masked by interocular suppression. However, in these abnormal observers the NDE-to-DE suppression was weak or absent. In the second experiment, we used the identical stimuli to measure the perceived contrast of a cyclopean grating by matching the binocular combined contrast to a standard contrast presented to the DE. These measures provide strong constraints for model fitting. We found asymmetric interocular interactions in binocular contrast perception, which was dependent on both contrast and spatial frequency in the same way as in phase perception. By introducing asymmetric parameters to the modified Ding-Sperling model including interocular contrast gain enhancement, we succeeded in accounting for both binocular combined phase and contrast simultaneously. Adding binocular contrast gain control to the modified Ding-Sperling model enabled us to predict the results of dichoptic and binocular contrast discrimination experiments and provides new insights into the mechanisms of abnormal binocular vision.

Dynamique d'une frontière libre : un siège fascinant de morphogénèse

NASA Astrophysics Data System (ADS)

Misbah, Chaouqi; Müller-Kurmbhaar, Heiner

Un front de solidification, dont le mouvement est limité par une simple diffusion, est le siège d'une myriade de morphogénèses statiques et dynamiques, allant d'une dendrite aux fractals, et d'un front cellulaire stationnaire au chaos spatio-temporel. Plusieurs de ces caractéristiques sont communes à une vaste liste de systèmes hors équilibre. Même l'organisation spatio-temporelle d'une population d'entités vivantes, telles que les bactéries, présente une forte similarité avec celle d'un front de croissance.

Maladie de Takayasu et polyarthrite rhumatoïde: une association rare - à propos d'une observation

PubMed Central

Frikha, Faten; Maazoun, Fatma; Snoussi, Mouna; Abid, Leila; Abid, Hanen; Bouassida, Walid; Kaddour, Neila; Bahloul, Zouhir

2012-01-01

L'artérite de Takayasu ou maladie de Takayasu (MT) et la polyarthrite rhumatoïde (PR) et sont deux maladies inflammatoires chroniques et leur association a été rapportée dans la littérature à travers quelques observations de cas sporadiques. Nous rapportons une nouvelle observation d'une telle association. Une patiente âgée de 44 ans, diagnostiquée avec une polyarthrite rhumatoïde à facteur rhumatoïde positif, qui a développé des céphalées avec des vertiges de caractère permanent. L'examen révélait un pouls radial et huméral abolis à droite, un souffle carotidien bilatéral et une tension artérielle imprenable à droite. L'artériographie a confirmé la présence d'une atteinte de l'arc aortique type MT. Le diagnostic d'une maladie de Takayasu associée à une polyarthrite rhumatoïde était retenu. La patiente était traitée par une corticothérapie (prednisone à la dose de 0,5 mg/kg par jour) et un traitement de fond par Méthotrexate avec une bonne réponse initiale. A travers notre observation et une revue de la littérature, les caractéristiques épidémiologiques, étiopathogéniques, cliniques, thérapeutiques et évolutives de cette association seront discutées. PMID:22937201

Perceptual training yields rapid improvements in visually impaired youth

PubMed Central

Nyquist, Jeffrey B.; Lappin, Joseph S.; Zhang, Ruyuan; Tadin, Duje

2016-01-01

Visual function demands coordinated responses to information over a wide field of view, involving both central and peripheral vision. Visually impaired individuals often seem to underutilize peripheral vision, even in absence of obvious peripheral deficits. Motivated by perceptual training studies with typically sighted adults, we examined the effectiveness of perceptual training in improving peripheral perception of visually impaired youth. Here, we evaluated the effectiveness of three training regimens: (1) an action video game, (2) a psychophysical task that combined attentional tracking with a spatially and temporally unpredictable motion discrimination task, and (3) a control video game. Training with both the action video game and modified attentional tracking yielded improvements in visual performance. Training effects were generally larger in the far periphery and appear to be stable 12 months after training. These results indicate that peripheral perception might be under-utilized by visually impaired youth and that this underutilization can be improved with only ~8 hours of perceptual training. Moreover, the similarity of improvements following attentional tracking and action video-game training suggest that well-documented effects of action video-game training might be due to the sustained deployment of attention to multiple dynamic targets while concurrently requiring rapid attending and perception of unpredictable events. PMID:27901026

Monitor, a vibrotactile aid for environmental perception: a field evaluation by four people with severe hearing and vision impairment.

PubMed

Ranjbar, Parivash; Stenström, Ingeborg

2013-01-01

Monitor is a portable vibrotactile aid to improve the ability of people with severe hearing impairment or deafblindness to detect, identify, and recognize the direction of sound-producing events. It transforms and adapts sounds to the frequency sensitivity range of the skin. The aid was evaluated in the field. Four females (44-54 years) with Usher Syndrome I (three with tunnel vision and one with only light perception) tested the aid at home and in traffic in three different field studies: without Monitor, with Monitor with an omnidirectional microphone, and with Monitor with a directional microphone. The tests were video-documented, and the two field studies with Monitor were initiated after five weeks of training. The detection scores with omnidirectional and directional microphones were 100% for three participants and above 57% for one, both in their home and traffic environments. In the home environment the identification scores with the omnidirectional microphone were 70%-97% and 58%-95% with the directional microphone. The corresponding values in traffic were 29%-100% and 65%-100%, respectively. Their direction perception was improved to some extent by both microphones. Monitor improved the ability of people with deafblindness to detect, identify, and recognize the direction of events producing sounds.

Stimulus factors in motion perception and spatial orientation

NASA Technical Reports Server (NTRS)

Post, R. B.; Johnson, C. A.

1984-01-01

The Malcolm horizon utilizes a large projected light stimulus Peripheral Vision Horizon Device (PVHD) as an attitude indicator in order to achieve a more compelling sense of roll than is obtained with smaller devices. The basic principle is that the larger stimulus is more similar to visibility of a real horizon during roll, and does not require fixation and attention to the degree that smaller displays do. Successful implementation of such a device requires adjustment of the parameters of the visual stimulus so that its effects on motion perception and spatial orientation are optimized. With this purpose in mind, the effects of relevant image variables on the perception of object motion, self motion and spatial orientation are reviewed.

Short-Term Memory; An Annotated Bibliography. Supplement 1.

ERIC Educational Resources Information Center

Fisher, Dennis F.

A compilation of 165 references dealing with short term memory, this bibliography supplements "Short-Term Memory: An Annotated Bibliography" (August 1968). The time period covered is predominantly June 1968 to June 1969. Such aspects and topics as psychometrics, motivation, human engineering, vision, auditory perception, verbal and nonverbal…

Changes in Vision: Teachers Engaging in Action Research

ERIC Educational Resources Information Center

Warren, Susan; Doorn, Dan; Green, James

2008-01-01

This investigation explored the effects of action research on teachers in a graduate education program. Mixed methods were utilized, combining a semantic differential study of student attitudes with qualitative analysis of students' perceptions of their experience as action researchers. Results indicate that participants perceived themselves as…

Exploration, anxiety, and spatial memory in transgenic anophthalmic mice.

PubMed

Buhot, M C; Dubayle, D; Malleret, G; Javerzat, S; Segu, L

2001-04-01

Contradictory results are found in the literature concerning the role of vision in the perception of space or in spatial navigation, in part because of the lack of murine models of total blindness used so far. The authors evaluated the spatial abilities of anophthalmic transgenic mice. These mice did not differ qualitatively from their wild-type littermates in general locomotor activity, spontaneous alternation, object exploration, or anxiety, but their level of exploratory activity was generally lower. In the spatial version of the water maze, they displayed persistent thigmotaxic behavior and showed severe spatial learning impairments. However, their performances improved with training, suggesting that they may have acquired a rough representation of the platform position. These results suggest that modalities other than vision enable some degree of spatial processing in proximal and structured spaces but that vision is critical for accurate spatial navigation.

Enhancing Motion-In-Depth Perception of Random-Dot Stereograms.

PubMed

Zhang, Di; Nourrit, Vincent; De Bougrenet de la Tocnaye, Jean-Louis

2018-07-01

Random-dot stereograms have been widely used to explore the neural mechanisms underlying binocular vision. Although they are a powerful tool to stimulate motion-in-depth (MID) perception, published results report some difficulties in the capacity to perceive MID generated by random-dot stereograms. The purpose of this study was to investigate whether the performance of MID perception could be improved using an appropriate stimulus design. Sixteen inexperienced observers participated in the experiment. A training session was carried out to improve the accuracy of MID detection before the experiment. Four aspects of stimulus design were investigated: presence of a static reference, background texture, relative disparity, and stimulus contrast. Participants' performance in MID direction discrimination was recorded and compared to evaluate whether varying these factors helped MID perception. Results showed that only the presence of background texture had a significant effect on MID direction perception. This study provides suggestions for the design of 3D stimuli in order to facilitate MID perception.

Color vision abnormality as an initial presentation of the complete type of congenital stationary night blindness.

PubMed

Tan, Xue; Aoki, Aya; Yanagi, Yasuo

2013-01-01

Patients with the complete form of congenital stationary night blindness (CSNB) often have reduced visual acuity, myopia, impaired night vision, and sometimes nystagmus and strabismus, however, they seldom complain of color vision abnormality. A 17-year-old male who was at technical school showed abnormalities in the color perception test for employment, and was referred to our hospital for a detailed examination. He had no family history of color vision deficiency and no other symptoms. During the initial examination, his best-corrected visual acuity was 1.2 in both eyes. His fundus showed no abnormalities except for somewhat yellowish reflex in the fovea of both eyes. Electroretinogram (ERG) showed a good response in cone ERG and 30 Hz flicker ERG, however, the bright flash, mixed rod and cone ERG showed a negative type with a reduced b-wave (positive deflection). There was no response in the rod ERG, either. From the findings of the typical ERG, the patient was diagnosed with complete congenital stationary night blindness. This case underscores the importance of ERG in order to diagnose the cause of a color vision anomaly.

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

PubMed Central

Barriga-Rivera, Alejandro; Bareket, Lilach; Goding, Josef; Aregueta-Robles, Ulises A.; Suaning, Gregg J.

2017-01-01

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. PMID:29184478

The visually impaired patient.

PubMed

Rosenberg, Eric A; Sperazza, Laura C

2008-05-15

Blindness or low vision affects more than 3 million Americans 40 years and older, and this number is projected to reach 5.5 million by 2020. In addition to treating a patient's vision loss and comorbid medical issues, physicians must be aware of the physical limitations and social issues associated with vision loss to optimize health and independent living for the visually impaired patient. In the United States, the four most prevalent etiologies of vision loss in persons 40 years and older are age-related macular degeneration, cataracts, glaucoma, and diabetic retinopathy. Exudative macular degeneration is treated with laser therapy, and progression of nonexudative macular degeneration in its advanced stages may be slowed with high-dose antioxidant and zinc regimens. The value of screening for glaucoma is uncertain; management of this condition relies on topical ocular medications. Cataract symptoms include decreased visual acuity, decreased color perception, decreased contrast sensitivity, and glare disability. Lifestyle and environmental interventions can improve function in patients with cataracts, but surgery is commonly performed if the condition worsens. Diabetic retinopathy responds to tight glucose control, and severe cases marked by macular edema are treated with laser photocoagulation. Vision-enhancing devices can help magnify objects, and nonoptical interventions include special filters and enhanced lighting.

Choroïdopathie du lupus érythémateux systémique, à propos d'un cas

PubMed Central

Idriss, Benatiya Andaloussi; Fouad, Chraibi; Salima, Bhallil; Meryem, Abdellaoui; Hicham, Tahri

2013-01-01

Le lupus érythémateux systémique (LES) est une maladie auto-immune multi systémique d’étiologie inconnue. Nous rapportons une manifestation très rare du LES représentée par une choroidopathie bilatérale sans hypertension artérielle associée. Il s'agit d'une patiente âgée de 45 ans, suivie pour un LES depuis 5 ans, qui présente une baisse de l'acuité visuelle bilatérale et progressive depuis 3 mois. L'examen du fond d’œil, complété l'angiographie à la fluorescéine et la tomographie en cohérence optique, retrouve un décollement séreux rétinien (DSR) multifocal et bilatéral. L’évolution après corticothérapie systémique est marquée par une amélioration de l'acuité visuelle et une régression du DSR. L'atteinte oculaire au cours du LED est dominée par la kérato-conjonctivite sèche (1/4 à 1/3 des cas). La choroïdopathie est plus rare: seulement une trentaine de cas sont rapportés dans littérature. Elle se manifeste par un décollement séreux rétinien et est habituellement observée chez les patients présentant une néphropathie ou une hypertension artérielle, ce qui n'est pas le cas de notre observation. L'apparition d'une atteinte oculaire au cours du LES peut annoncer une poussée d'atteinte systémique et doit susciter une enquête appropriée. PMID:23717732

How (and why) the visual control of action differs from visual perception

PubMed Central

Goodale, Melvyn A.

2014-01-01

Vision not only provides us with detailed knowledge of the world beyond our bodies, but it also guides our actions with respect to objects and events in that world. The computations required for vision-for-perception are quite different from those required for vision-for-action. The former uses relational metrics and scene-based frames of reference while the latter uses absolute metrics and effector-based frames of reference. These competing demands on vision have shaped the organization of the visual pathways in the primate brain, particularly within the visual areas of the cerebral cortex. The ventral ‘perceptual’ stream, projecting from early visual areas to inferior temporal cortex, helps to construct the rich and detailed visual representations of the world that allow us to identify objects and events, attach meaning and significance to them and establish their causal relations. By contrast, the dorsal ‘action’ stream, projecting from early visual areas to the posterior parietal cortex, plays a critical role in the real-time control of action, transforming information about the location and disposition of goal objects into the coordinate frames of the effectors being used to perform the action. The idea of two visual systems in a single brain might seem initially counterintuitive. Our visual experience of the world is so compelling that it is hard to believe that some other quite independent visual signal—one that we are unaware of—is guiding our movements. But evidence from a broad range of studies from neuropsychology to neuroimaging has shown that the visual signals that give us our experience of objects and events in the world are not the same ones that control our actions. PMID:24789899

Outcome of endoscopic trans-ethmosphenoid optic canal decompression for indirect traumatic optic neuropathy in children.

PubMed

Yu, Bo; Chen, Yingbai; Ma, Yingjie; Tu, Yunhai; Wu, Wencan

2018-06-26

To evaluate the safety and outcomes of endoscopic trans-ethmosphenoid optic canal decompression (ETOCD) for children with indirect traumatic optic neuropathy (ITON). From July 1st, 2008 to July 1st, 2015, 62 children diagnosed with ITON who underwent ETOCD were reviewed. Main outcome measure was improvement in visual acuity after treatment. Altogether 62 children (62 eyes) with a mean age of 11.26 ± 4.14 years were included. Thirty-three (53.2%) of them had residual vision before surgery while 29 (46.8%) had no light perception (NLP). The overall visual acuity improvement rate after surgery was 54.84%. The improvement rate of patients with residual vision (69.70%) was significant higher than that of patients with no light perception (NLP) (37.9%) (P = 0.012). However, no significant difference was shown among patients with different residual vision (P = 0.630). Presence of orbital and/ or optic canal fracture and hemorrhage within the post-ethmoid and/or sphenoid sinus resulted in poor postoperative visual acuity, duration of presenting complaints did not affect final visual acuity or did not effect outcomes. Intervention performed in children presenting even after 7 days from the injury did not influence the final visual outcome. Three patients developed cerebrospinal fluid rhinorrhea and one encountered cavernous sinus hemorrhage during surgery. No other severe complications were observed. Children with residual vision had better postoperative visual prognosis and benefited more from ETOCD than children with NLP. Intervention performed in children presenting even after 7 days from the injury did not influence the final visual outcome, however, this needs to be reassessed in children presenting long after the injury.Treatment should still be recommended even for cases of delayed presentation to hospital.

How does glaucoma look?: patient perception of visual field loss.

PubMed

Crabb, David P; Smith, Nicholas D; Glen, Fiona C; Burton, Robyn; Garway-Heath, David F

2013-06-01

To explore patient perception of vision loss in glaucoma and, specifically, to test the hypothesis that patients do not recognize their impairment as a black tunnel effect or as black patches in their field of view. Clinic-based cross-sectional study. Fifty patients (age range, 52-82 years) with visual acuity better than 20/30 and with a range of glaucomatous visual field (VF) defects in both eyes, excluding those with very advanced disease (perimetrically blind). Participants underwent monocular VF testing in both eyes using a Humphrey Field Analyzer (HFA; Carl Zeiss Meditec, Dublin, CA; 24-2 Swedish interactive threshold algorithm standard tests) and other tests of visual function. Participants took part in a recorded interview during which they were asked if they were aware of their VF loss; if so, there were encouraged to describe it in their own words. Participants were shown 6 images modified in a variety of ways on a computer monitor and were asked to select the image that most closely represented their perception of their VF loss. Forced choice of an image best representing glaucomatous vision impairment. Participants had a range of VF defect severity: average HFA mean deviation was -8.7 dB (standard deviation [SD], 5.8 dB) and -10.5 dB (SD, 7.1 dB) in the right and left eyes, respectively. Thirteen patients (26%; 95% confidence interval [CI], 15%-40%) reported being completely unaware of their vision loss. None of the patients chose the images with a distinct black tunnel effect or black patches. Only 2 patients (4%; 95% CI, 0%-14%) chose the image with a tunnel effect with blurred edges. An image depicting blurred patches and another with missing patches was chosen by 54% (95% CI, 39%-68%) and 16% (95% CI, 7%-29%) of the patients, respectively. Content analysis of the transcripts from the recorded interviews indicated a frequent use of descriptors of visual symptoms associated with reported blur and missing features. Patients with glaucoma do not perceive their vision loss as a black tunnel effect or as black patches masking their field of view. These findings are important in the context of depicting the effects of glaucomatous vision loss and raising awareness for glaucoma detection. The author(s) have no proprietary or commercial interest in any materials discussed in this article. Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Audition dominates vision in duration perception irrespective of salience, attention, and temporal discriminability

PubMed Central

Ortega, Laura; Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Suzuki, Satoru

2014-01-01

Whereas the visual modality tends to dominate over the auditory modality in bimodal spatial perception, the auditory modality tends to dominate over the visual modality in bimodal temporal perception. Recent results suggest that the visual modality dominates bimodal spatial perception because spatial discriminability is typically greater for the visual than auditory modality; accordingly, visual dominance is eliminated or reversed when visual-spatial discriminability is reduced by degrading visual stimuli to be equivalent or inferior to auditory spatial discriminability. Thus, for spatial perception, the modality that provides greater discriminability dominates. Here we ask whether auditory dominance in duration perception is similarly explained by factors that influence the relative quality of auditory and visual signals. In contrast to the spatial results, the auditory modality dominated over the visual modality in bimodal duration perception even when the auditory signal was clearly weaker, when the auditory signal was ignored (i.e., the visual signal was selectively attended), and when the temporal discriminability was equivalent for the auditory and visual signals. Thus, unlike spatial perception where the modality carrying more discriminable signals dominates, duration perception seems to be mandatorily linked to auditory processing under most circumstances. PMID:24806403

Comparing sports vision among three groups of soft tennis adolescent athletes: Normal vision, refractive errors with and without correction.

PubMed

Chang, Shih-Tsun; Liu, Yen-Hsiu; Lee, Jiahn-Shing; See, Lai-Chu

2015-09-01

The effect of correcting static vision on sports vision is still not clear. To examine whether sports vision (depth perception [DP], dynamic visual acuity [DVA], eye movement [EM], peripheral vision [PV], and momentary vision [MV],) were different among soft tennis adolescent athletes with normal vision (Group A), with refractive error and corrected with (Group B) and without eyeglasses (Group C). A cross-section study was conducted. Soft tennis athletes aged 10-13 who played softball tennis for 2-5 years, and who were without any ocular diseases and without visual training for the past 3 months were recruited. DPs were measured in an absolute deviation (mm) between a moving rod and fixing rod (approaching at 25 mm/s, receding at 25 mm/s, approaching at 50 mm/s, receding at 50 mm/s) using electric DP tester. A smaller deviation represented better DP. DVA, EM, PV, and MV were measured on a scale from 1 (worse) to 10 (best) using ATHLEVISION software. Chi-square test and Kruskal-Wallis test was used to compare the data among the three study groups. A total of 73 athletes (37 in Group A, 8 in Group B, 28 in Group C) were enrolled in this study. All four items of DP showed significant difference among the three study groups (P = 0.0051, 0.0004, 0.0095, 0.0021). PV displayed significant difference among the three study groups (P = 0.0044). There was no significant difference in DVA, EM, and MV among the three study groups. Significant better DP and PV were seen among soft tennis adolescent athletes with normal vision than those with refractive error regardless whether they had eyeglasses corrected. On the other hand, DVA, EM, and MV were similar among the three study groups.

Intentions and Perceptions: In Search of Alignment

ERIC Educational Resources Information Center

Sindberg, Laura K.

2009-01-01

Teachers plan for instruction in band, choir, and orchestra; this typically includes selecting repertoire and planning outcomes and strategies for achieving those goals with a vision toward excellent musical performance. Teachers in school music ensembles plan instruction that will lead to student learning. In the ensemble setting, this learning…

The Effect of Multimedia-Based Learning on the Concept Learning Levels and Attitudes of Students

ERIC Educational Resources Information Center

Beydogan, H. Ömer; Hayran, Zeynel

2015-01-01

Problem Statement: Rich stimuli received by sensory organs such as vision, hearing, and touch are important elements that affect an individual's perception, identification, classification, and conceptualization of the external world. In primary education, since students perform conceptual abstraction based upon concrete characteristics, when they…

Research and Studies Directory for Manpower, Personnel, and Training

DTIC Science & Technology

1989-05-01

LOUIS MO 314-889-6805 CONTROL OF BIOSONAR BEHAVIOR BY THE AUDITORY CORTEX TANGNEY J AIR FORCE OFFICE OF SCIENTIFIC RESEARCH 202-767-5021 A MODEL FOR...VISUAL ATTENTION AUDITORY PERCEPTION OF COMPLEX SOUNDS CONTROL OF BIOSONAR BEHAVIOR BY THE AUDITORY CORTEX EYE MOVEMENTS AND SPATIAL PATTERN VISION EYE

Sensory Sensitivities and Discriminations and their Roles in Aviation

DTIC Science & Technology

1991-10-31

asymmetry. Neurology, in press. 5. Zihl JD, Von Cramon D & Mai N (1983) Selective disturbance of movement vision after bilateral brain damage. Brain...1970) Electrophysiological correlate of binocular depth perception in man. Nature 255, 92-4. 1971 16. Regan D & Sperling HG (1971) A method of evoking

Learning Disabilities: The Decade Ahead.

ERIC Educational Resources Information Center

Krasnoff, Margaret J., Ed.

Presented are ten papers given at a 1974 conference focusing on realistic goals for serving learning disabled children in the decade ahead. Papers have the following titles and authors: "Introduction and Overview of the Problem of the Conference" (W. Cruickshank); "Concepts of Vision in Relation to Perception" (G. Getman); "Motor Activities and…

A Reality Rub Crisis Intervention: "I Wish There Was a Law against Belts."

ERIC Educational Resources Information Center

Long, Nicholas J.; Techet, Bonnie

1994-01-01

Presents Life Space Interview (LSI) or Life Space Crisis Intervention (LSCI) with second-grade student from threatening home environment. Uses Reality Rub Intervention Interview, focusing on five variations: distorted perceptions, tunnel vision, faulty thinking, avoidance, and alibi. Describes incident that led to intervention, interview itself,…

The Effect of Visual Experience on Perceived Haptic Verticality When Tilted in the Roll Plane

PubMed Central

Cuturi, Luigi F.; Gori, Monica

2017-01-01

The orientation of the body in space can influence perception of verticality leading sometimes to biases consistent with priors peaked at the most common head and body orientation, that is upright. In this study, we investigate haptic perception of verticality in sighted individuals and early and late blind adults when tilted counterclockwise in the roll plane. Participants were asked to perform a stimulus orientation discrimination task with their body tilted to their left ear side 90° relative to gravity. Stimuli were presented by using a motorized haptic bar. In order to test whether different reference frames relative to the head influenced perception of verticality, we varied the position of the stimulus on the body longitudinal axis. Depending on the stimulus position sighted participants tended to have biases away or toward their body tilt. Visually impaired individuals instead show a different pattern of verticality estimations. A bias toward head and body tilt (i.e., Aubert effect) was observed in late blind individuals. Interestingly, no strong biases were observed in early blind individuals. Overall, these results posit visual sensory information to be fundamental in influencing the haptic readout of proprioceptive and vestibular information about body orientation relative to gravity. The acquisition of an idiotropic vector signaling the upright might take place through vision during development. Regarding early blind individuals, independent spatial navigation experience likely enhanced by echolocation behavior might have a role in such acquisition. In the case of participants with late onset blindness, early experience of vision might lead them to anchor their visually acquired priors to the haptic modality with no disambiguation between head and body references as observed in sighted individuals (Fraser et al., 2015). With our study, we aim to investigate haptic perception of gravity direction in unusual body tilts when vision is absent due to visual impairment. Insofar, our findings throw light on the influence of proprioceptive/vestibular sensory information on haptic perceived verticality in blind individuals showing how this phenomenon is affected by visual experience. PMID:29270109

Human V4 Activity Patterns Predict Behavioral Performance in Imagery of Object Color.

PubMed

Bannert, Michael M; Bartels, Andreas

2018-04-11

Color is special among basic visual features in that it can form a defining part of objects that are engrained in our memory. Whereas most neuroimaging research on human color vision has focused on responses related to external stimulation, the present study investigated how sensory-driven color vision is linked to subjective color perception induced by object imagery. We recorded fMRI activity in male and female volunteers during viewing of abstract color stimuli that were red, green, or yellow in half of the runs. In the other half we asked them to produce mental images of colored, meaningful objects (such as tomato, grapes, banana) corresponding to the same three color categories. Although physically presented color could be decoded from all retinotopically mapped visual areas, only hV4 allowed predicting colors of imagined objects when classifiers were trained on responses to physical colors. Importantly, only neural signal in hV4 was predictive of behavioral performance in the color judgment task on a trial-by-trial basis. The commonality between neural representations of sensory-driven and imagined object color and the behavioral link to neural representations in hV4 identifies area hV4 as a perceptual hub linking externally triggered color vision with color in self-generated object imagery. SIGNIFICANCE STATEMENT Humans experience color not only when visually exploring the outside world, but also in the absence of visual input, for example when remembering, dreaming, and during imagery. It is not known where neural codes for sensory-driven and internally generated hue converge. In the current study we evoked matching subjective color percepts, one driven by physically presented color stimuli, the other by internally generated color imagery. This allowed us to identify area hV4 as the only site where neural codes of corresponding subjective color perception converged regardless of its origin. Color codes in hV4 also predicted behavioral performance in an imagery task, suggesting it forms a perceptual hub for color perception. Copyright © 2018 the authors 0270-6474/18/383657-12$15.00/0.

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

NASA Astrophysics Data System (ADS)

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 regeneration and deviations in regular circadian rhythms. Therefore participants in vision studies using "Virtual Reality" appliances with fixed vision fields and emitting a spike liked spectral bands (on basis of OLED and AMOLED diodes) different from spectra of ambient illuminators should be accordingly warned about potential health risks.

Predator perception and the interrelation between different forms of protective coloration

PubMed Central

Stevens, Martin

2007-01-01

Animals possess a range of defensive markings to reduce the risk of predation, including warning colours, camouflage, eyespots and mimicry. These different strategies are frequently considered independently, and with little regard towards predator vision, even though they may be linked in various ways and can be fully understood only in terms of predator perception. For example, camouflage and warning coloration need not be mutually exclusive, and may frequently exploit similar features of visual perception. This paper outlines how different forms of protective markings can be understood from predator perception and illustrates how this is fundamental in determining the mechanisms underlying, and the interrelation between, different strategies. Suggestions are made for future work, and potential mechanisms discussed in relation to various forms of defensive coloration, including disruptive coloration, eyespots, dazzle markings, motion camouflage, aposematism and mimicry. PMID:17426012

Understanding face perception by means of human electrophysiology.

PubMed

Rossion, Bruno

2014-06-01

Electrophysiological recordings on the human scalp provide a wealth of information about the temporal dynamics and nature of face perception at a global level of brain organization. The time window between 100 and 200 ms witnesses the transition between low-level and high-level vision, an N170 component correlating with conscious interpretation of a visual stimulus as a face. This face representation is rapidly refined as information accumulates during this time window, allowing the individualization of faces. To improve the sensitivity and objectivity of face perception measures, it is increasingly important to go beyond transient visual stimulation by recording electrophysiological responses at periodic frequency rates. This approach has recently provided face perception thresholds and the first objective signature of integration of facial parts in the human brain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Elevated arousal levels enhance contrast perception.

PubMed

Kim, Dongho; Lokey, Savannah; Ling, Sam

2017-02-01

Our state of arousal fluctuates from moment to moment-fluctuations that can have profound impacts on behavior. Arousal has been proposed to play a powerful, widespread role in the brain, influencing processes as far ranging as perception, memory, learning, and decision making. Although arousal clearly plays a critical role in modulating behavior, the mechanisms underlying this modulation remain poorly understood. To address this knowledge gap, we examined the modulatory role of arousal on one of the cornerstones of visual perception: contrast perception. Using a reward-driven paradigm to manipulate arousal state, we discovered that elevated arousal state substantially enhances visual sensitivity, incurring a multiplicative modulation of contrast response. Contrast defines vision, determining whether objects appear visible or invisible to us, and these results indicate that one of the consequences of decreased arousal state is an impaired ability to visually process our environment.

The dynamic-stimulus advantage of visual symmetry perception.

PubMed

Niimi, Ryosuke; Watanabe, Katsumi; Yokosawa, Kazuhiko

2008-09-01

It has been speculated that visual symmetry perception from dynamic stimuli involves mechanisms different from those for static stimuli. However, previous studies found no evidence that dynamic stimuli lead to active temporal processing and improve symmetry detection. In this study, four psychophysical experiments investigated temporal processing in symmetry perception using both dynamic and static stimulus presentations of dot patterns. In Experiment 1, rapid successive presentations of symmetric patterns (e.g., 16 patterns per 853 ms) produced more accurate discrimination of orientations of symmetry axes than static stimuli (single pattern presented through 853 ms). In Experiments 2-4, we confirmed that the dynamic-stimulus advantage depended upon presentation of a large number of unique patterns within a brief period (853 ms) in the dynamic conditions. Evidently, human vision takes advantage of temporal processing for symmetry perception from dynamic stimuli.

Adaptive multisensor fusion for planetary exploration rovers

NASA Technical Reports Server (NTRS)

Collin, Marie-France; Kumar, Krishen; Pampagnin, Luc-Henri

1992-01-01

The purpose of the adaptive multisensor fusion system currently being designed at NASA/Johnson Space Center is to provide a robotic rover with assured vision and safe navigation capabilities during robotic missions on planetary surfaces. Our approach consists of using multispectral sensing devices ranging from visible to microwave wavelengths to fulfill the needs of perception for space robotics. Based on the illumination conditions and the sensors capabilities knowledge, the designed perception system should automatically select the best subset of sensors and their sensing modalities that will allow the perception and interpretation of the environment. Then, based on reflectance and emittance theoretical models, the sensor data are fused to extract the physical and geometrical surface properties of the environment surface slope, dielectric constant, temperature and roughness. The theoretical concepts, the design and first results of the multisensor perception system are presented.

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

PubMed

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 and Experimental Optometry © 2015 Optometry Australia.

Lignes directrices simplifiées sur les lipides

PubMed Central

Allan, G. Michael; Lindblad, Adrienne J.; Comeau, Ann; Coppola, John; Hudson, Brianne; Mannarino, Marco; McMinis, Cindy; Padwal, Raj; Schelstraete, Christine; Zarnke, Kelly; Garrison, Scott; Cotton, Candra; Korownyk, Christina; McCormack, James; Nickel, Sharon; Kolber, Michael R.

2015-01-01

Résumé Objectif Produire un guide de pratique clinique comportant une approche simplifiée à la prévention primaire des maladies cardiovasculaires (MCV), en insistant sur l’estimation du risque de MCV et la prise en charge des profils lipidiques à l’intention des cliniciens de soins primaires et leurs équipes; nous avons recherché la contribution de professionnels des soins primaires qui n’avaient que peu ou pas de conflits d’intérêts et nous nous sommes concentrés sur les données probantes de la plus haute qualité accessibles. Méthodes Neuf professionnels de la santé (4 médecins de famille, 2 internistes, 1 infirmière praticienne, 1 infirmière autorisée et 1 pharmacienne) et 1 membre non votant (pharmacienne gestionnaire de projet) formaient le comité principal appelé le Lipid Pathway Committee (le comité). La sélection des membres s’est fondée sur la profession, le milieu de pratique et son emplacement. Les membres ont divulgué tous leurs conflits d’intérêts potentiels ou réels. Le processus d’élaboration des lignes directrices était itératif et s’appuyait sur des affichages en ligne, une révision détaillée des données probantes, des réunions par téléphone et en ligne. Le comité a cerné 12 questions prioritaires à répondre. Le groupe de révision des données probantes a répondu à ces questions. À la suite d’un examen des réponses, les principales recommandations ont été formulées par consensus du comité. Nous avons produit une ébauche des lignes directrices qui a ensuite été peaufinée, distribuée à un groupe de cliniciens (médecins de famille, autres spécialistes, pharmaciens, infirmières et infirmières praticiennes) et à des patients pour obtenir de la rétroaction, la réviser en conséquence et le comité l’a ensuite finalisée. Recommandations Des recommandations sont présentées concernant le dépistage et les analyses, les évaluations du risque, le suivi, de même que le rôle de l’acide acétylsalicylique en prévention primaire. Conclusion Ces lignes directrices simplifiées sur les lipides offrent des recommandations pratiques pour la prévention et le traitement des MCV à l’intention des professionnels des soins primaires. Toutes les recommandations ont pour but d’aider à la prise de décision conjointement avec les patients plutôt que de la dicter.

Aspherics in spectacle lenses

NASA Astrophysics Data System (ADS)

Dürsteler, Juan Carlos

2016-12-01

A review of the use of aspherics in the last decades, understood in a broad sense as encompassing single-vision lenses with conicoid surfaces and free-form and progressive addition lenses (PALs) as well, is provided. The appearance of conicoid surfaces to correct aphakia and later to provide thinner and more aesthetically appealing plus lenses and the introduction of PALs and free-form surfaces have shaped the advances in spectacle lenses in the last three decades. This document basically considers the main target optical aberrations, the idiosyncrasy of single lenses for correction of refractive errors and the restrictions and particularities of PAL design and their links to science vision and perception.

Colour, vision and coevolution in avian brood parasitism.

PubMed

Stoddard, Mary Caswell; Hauber, Mark E

2017-07-05

The coevolutionary interactions between avian brood parasites and their hosts provide a powerful system for investigating the diversity of animal coloration. Specifically, reciprocal selection pressure applied by hosts and brood parasites can give rise to novel forms and functions of animal coloration, which largely differ from those that arise when selection is imposed by predators or mates. In the study of animal colours, avian brood parasite-host dynamics therefore invite special consideration. Rapid advances across disciplines have paved the way for an integrative study of colour and vision in brood parasite-host systems. We now know that visually driven host defences and host life history have selected for a suite of phenotypic adaptations in parasites, including mimicry, crypsis and supernormal stimuli. This sometimes leads to vision-based host counter-adaptations and increased parasite trickery. Here, we review vision-based adaptations that arise in parasite-host interactions, emphasizing that these adaptations can be visual/sensory, cognitive or phenotypic in nature. We highlight recent breakthroughs in chemistry, genomics, neuroscience and computer vision, and we conclude by identifying important future directions. Moving forward, it will be essential to identify the genetic and neural bases of adaptation and to compare vision-based adaptations to those arising in other sensory modalities.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Author(s).

Mode de révélation particulier d'une tumeur brune chez une patiente hémodialysée chronique

PubMed Central

El Harraqui, Ryme; Karimi, Ilham; Chemlal, Abdeljalil; Ismaili, Fatiha Alaoui; Haddiya, Intissar

2014-01-01

Les tumeurs brunes constituent une complication rare mais sévère de la dialyse, le plus souvent asymptomatique. Nous rapportons le cas d'une patiente dont le mode de révélation de la tumeur brune fut atypique. Observation médicale: Madame F. est une patiente hémodialysée chronique depuis 14 ans suite à une néphropathie indéterminée. Sur le plan phosphocalcique, elle présente une ostéoporose depuis plus de 10 ans, ainsi qu'une hyperparathyroïdie secondaire. A la date du 24 octobre 2013, elle rapporte qu'elle a constaté la présence d'une petite « bosse » pariétale, apparue de façon spontanée la veille, sans notion de traumatisme. A l'examen clinique, nous trouvons une petite tuméfaction de 2cm de diamètre environs, de consistance dure, indolore, mobile par rapport au cuir chevelu. L’échographie a conclu à un lipome. Le lendemain matin, la patiente entre dans un état de coma profond. Le scanner cérébral a révélé la présence d'un hématome extradural associé à un hématome superficiel extra-crânien en regard d'une lyse de l'os pariétal, qui est en fait une tumeur brune. La patiente est transférée en réanimation où elle décède dans la journée. PMID:25422698

The Handbook of Medical Image Perception and Techniques

NASA Astrophysics Data System (ADS)

Samei, Ehsan; Krupinski, Elizabeth

2014-07-01

1. Medical image perception Ehsan Samei and Elizabeth Krupinski; Part I. Historical Reflections and Theoretical Foundations: 2. A short history of image perception in medical radiology Harold Kundel and Calvin Nodine; 3. Spatial vision research without noise Arthur Burgess; 4. Signal detection theory, a brief history Arthur Burgess; 5. Signal detection in radiology Arthur Burgess; 6. Lessons from dinners with the giants of modern image science Robert Wagner; Part II. Science of Image Perception: 7. Perceptual factors in reading medical images Elizabeth Krupinski; 8. Cognitive factors in reading medical images David Manning; 9. Satisfaction of search in traditional radiographic imaging Kevin Berbaum, Edmund Franken, Robert Caldwell and Kevin Schartz; 10. The role of expertise in radiologic image interpretation Calvin Nodine and Claudia Mello-Thoms; 11. A primer of image quality and its perceptual relevance Robert Saunders and Ehsan Samei; 12. Beyond the limitations of human vision Maria Petrou; Part III. Perception Metrology: 13. Logistical issues in designing perception experiments Ehsan Samei and Xiang Li; 14. ROC analysis: basic concepts and practical applications Georgia Tourassi; 15. Multi-reader ROC Steve Hillis; 16. Recent developments in FROC methodology Dev Chakraborty; 17. Observer models as a surrogate to perception experiments Craig Abbey and Miguel Eckstein; 18. Implementation of observer models Matthew Kupinski; Part IV. Decision Support and Computer Aided Detection: 19. CAD: an image perception perspective Maryellen Giger and Weijie Chen; 20. Common designs of CAD studies Yulei Jiang; 21. Perceptual effect of CAD in reading chest images Matthew Freedman and Teresa Osicka; 22. Perceptual issues in mammography and CAD Michael Ulissey; 23. How perceptual factors affect the use and accuracy of CAD for interpretation of CT images Ronald Summers; 24. CAD: risks and benefits for radiologists' decisions Eugenio Alberdi, Andrey Povyakalo, Lorenzo Strigini and Peter Ayton; Part V. Optimization and Practical Issues: 25. Optimization of 2D and 3D radiographic systems Jeff Siewerdson; 26. Applications of AFC methodology in optimization of CT imaging systems Kent Ogden and Walter Huda; 27. Perceptual issues in reading mammograms Margarita Zuley; 28. Perceptual optimization of display processing techniques Richard Van Metter; 29. Optimization of display systems Elizabeth Krupinski and Hans Roehrig; 30. Ergonomic radiologist workplaces in the PACS environment Carl Zylack; Part VI. Epilogue: 31. Future prospects of medical image perception Ehsan Samei and Elizabeth Krupinski; Index.

The Handbook of Medical Image Perception and Techniques

NASA Astrophysics Data System (ADS)

Samei, Ehsan; Krupinski, Elizabeth

2009-12-01

1. Medical image perception Ehsan Samei and Elizabeth Krupinski; Part I. Historical Reflections and Theoretical Foundations: 2. A short history of image perception in medical radiology Harold Kundel and Calvin Nodine; 3. Spatial vision research without noise Arthur Burgess; 4. Signal detection theory, a brief history Arthur Burgess; 5. Signal detection in radiology Arthur Burgess; 6. Lessons from dinners with the giants of modern image science Robert Wagner; Part II. Science of Image Perception: 7. Perceptual factors in reading medical images Elizabeth Krupinski; 8. Cognitive factors in reading medical images David Manning; 9. Satisfaction of search in traditional radiographic imaging Kevin Berbaum, Edmund Franken, Robert Caldwell and Kevin Schartz; 10. The role of expertise in radiologic image interpretation Calvin Nodine and Claudia Mello-Thoms; 11. A primer of image quality and its perceptual relevance Robert Saunders and Ehsan Samei; 12. Beyond the limitations of human vision Maria Petrou; Part III. Perception Metrology: 13. Logistical issues in designing perception experiments Ehsan Samei and Xiang Li; 14. ROC analysis: basic concepts and practical applications Georgia Tourassi; 15. Multi-reader ROC Steve Hillis; 16. Recent developments in FROC methodology Dev Chakraborty; 17. Observer models as a surrogate to perception experiments Craig Abbey and Miguel Eckstein; 18. Implementation of observer models Matthew Kupinski; Part IV. Decision Support and Computer Aided Detection: 19. CAD: an image perception perspective Maryellen Giger and Weijie Chen; 20. Common designs of CAD studies Yulei Jiang; 21. Perceptual effect of CAD in reading chest images Matthew Freedman and Teresa Osicka; 22. Perceptual issues in mammography and CAD Michael Ulissey; 23. How perceptual factors affect the use and accuracy of CAD for interpretation of CT images Ronald Summers; 24. CAD: risks and benefits for radiologists' decisions Eugenio Alberdi, Andrey Povyakalo, Lorenzo Strigini and Peter Ayton; Part V. Optimization and Practical Issues: 25. Optimization of 2D and 3D radiographic systems Jeff Siewerdson; 26. Applications of AFC methodology in optimization of CT imaging systems Kent Ogden and Walter Huda; 27. Perceptual issues in reading mammograms Margarita Zuley; 28. Perceptual optimization of display processing techniques Richard Van Metter; 29. Optimization of display systems Elizabeth Krupinski and Hans Roehrig; 30. Ergonomic radiologist workplaces in the PACS environment Carl Zylack; Part VI. Epilogue: 31. Future prospects of medical image perception Ehsan Samei and Elizabeth Krupinski; Index.

Mimicking cataract-induced visual dysfunction by means of protein denaturation in egg albumen

NASA Astrophysics Data System (ADS)

Mandracchia, B.; Finizio, A.; Ferraro, P.

2016-03-01

As the world's population ages, cataract-induced visual dysfunction and blindness is on the increase. This is a significant global problem. The most common symptoms of cataracts are glared and blurred vision. Usually, people with cataract have trouble seeing and reading at distance or in low light and also their color perception is altered. Furthermore, cataract is a sneaky disease as it is usually a very slow but progressive process, which creates adaptation so that patients find it difficult to recognize. All this can be very difficult to explain, so we built and tested an optical device to help doctors giving comprehensive answers to the patients' symptoms. This device allows visualizing how cataract impairs vision mimicking the optical degradation of the crystalline related cataracts. This can be a valuable optical tool for medical education as well as to provide a method to illustrate the patients how cataract progression process will affect their vision.

Atypical cytomegalovirus retinitis in non-Hodgkin's lymphoma.

PubMed

Tyagi, Mudit; Ambiya, Vikas; Mathai, Annie; Narayanan, Raja

2015-08-03

A 54-year-old woman, a known case of non-Hodgkin's lymphoma (NHL) in complete remission, presented with floaters and diminution of vision in her left eye. The eye had vitritis with non-haemorrhagic retinitis mimicking intraocular lymphoma and acute retinal necrosis. A vitreous sample was positive for cytomegalovirus (CMV) and herpes simplex virus 1 (HSV-1) DNA by PCR. The possibility of intraocular lymphoma was not confirmed by the immunohistochemistry of the vitreous sample. The patient had a relapse of NHL along with rapid deterioration of vision in her left eye to no perception of light, due to optic nerve involvement. The right eye developed a new patch of focal haemorrhagic retinitis threatening the fovea. Based on the laboratory results and the clinical findings, she was successfully managed as a case of bilateral CMV retinitis and the vision in her right eye was salvaged. 2015 BMJ Publishing Group Ltd.

Quantifying nonhomogeneous colors in agricultural materials. Part II: comparison of machine vision and sensory panel evaluations.

PubMed

Balaban, M O; Aparicio, J; Zotarelli, M; Sims, C

2008-11-01

The average colors of mangos and apples were measured using machine vision. A method to quantify the perception of nonhomogeneous colors by sensory panelists was developed. Three colors out of several reference colors and their perceived percentage of the total sample area were selected by untrained panelists. Differences between the average colors perceived by panelists and those from the machine vision were reported as DeltaE values (color difference error). Effects of nonhomogeneity of color, and using real samples or their images in the sensory panels on DeltaE were evaluated. In general, samples with more nonuniform colors had higher DeltaE values, suggesting that panelists had more difficulty in evaluating more nonhomogeneous colors. There was no significant difference in DeltaE values between the real fruits and their screen image, therefore images can be used to evaluate color instead of the real samples.

Optoelectronic vision

NASA Astrophysics Data System (ADS)

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.

Algorithms and architectures for robot vision

NASA Technical Reports Server (NTRS)

Schenker, Paul S.

1990-01-01

The scope of the current work is to develop practical sensing implementations for robots operating in complex, partially unstructured environments. A focus in this work is to develop object models and estimation techniques which are specific to requirements of robot locomotion, approach and avoidance, and grasp and manipulation. Such problems have to date received limited attention in either computer or human vision - in essence, asking not only how perception is in general modeled, but also what is the functional purpose of its underlying representations. As in the past, researchers are drawing on ideas from both the psychological and machine vision literature. Of particular interest is the development 3-D shape and motion estimates for complex objects when given only partial and uncertain information and when such information is incrementally accrued over time. Current studies consider the use of surface motion, contour, and texture information, with the longer range goal of developing a fused sensing strategy based on these sources and others.

Stereo-vision-based terrain mapping for off-road autonomous navigation

NASA Astrophysics Data System (ADS)

Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

2009-05-01

Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as nogo regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

A perception theory in mind-body medicine: guided imagery and mindful meditation as cross-modal adaptation.

PubMed

Bedford, Felice L

2012-02-01

A new theory of mind-body interaction in healing is proposed based on considerations from the field of perception. It is suggested that the combined effect of visual imagery and mindful meditation on physical healing is simply another example of cross-modal adaptation in perception, much like adaptation to prism-displaced vision. It is argued that psychological interventions produce a conflict between the perceptual modalities of the immune system and vision (or touch), which leads to change in the immune system in order to realign the modalities. It is argued that mind-body interactions do not exist because of higher-order cognitive thoughts or beliefs influencing the body, but instead result from ordinary interactions between lower-level perceptual modalities that function to detect when sensory systems have made an error. The theory helps explain why certain illnesses may be more amenable to mind-body interaction, such as autoimmune conditions in which a sensory system (the immune system) has made an error. It also renders sensible erroneous changes, such as those brought about by "faith healers," as conflicts between modalities that are resolved in favor of the wrong modality. The present view provides one of very few psychological theories of how guided imagery and mindfulness meditation bring about positive physical change. Also discussed are issues of self versus non-self, pain, cancer, body schema, attention, consciousness, and, importantly, developing the concept that the immune system is a rightful perceptual modality. Recognizing mind-body healing as perceptual cross-modal adaptation implies that a century of cross-modal perception research is applicable to the immune system.

Stereo Vision Based Terrain Mapping for Off-Road Autonomous Navigation

NASA Technical Reports Server (NTRS)

Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

2009-01-01

Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as no-go regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

Vision Sensor-Based Road Detection for Field Robot Navigation

PubMed Central

Lu, Keyu; Li, Jian; An, Xiangjing; He, Hangen

2015-01-01

Road detection is an essential component of field robot navigation systems. Vision sensors play an important role in road detection for their great potential in environmental perception. In this paper, we propose a hierarchical vision sensor-based method for robust road detection in challenging road scenes. More specifically, for a given road image captured by an on-board vision sensor, we introduce a multiple population genetic algorithm (MPGA)-based approach for efficient road vanishing point detection. Superpixel-level seeds are then selected in an unsupervised way using a clustering strategy. Then, according to the GrowCut framework, the seeds proliferate and iteratively try to occupy their neighbors. After convergence, the initial road segment is obtained. Finally, in order to achieve a globally-consistent road segment, the initial road segment is refined using the conditional random field (CRF) framework, which integrates high-level information into road detection. We perform several experiments to evaluate the common performance, scale sensitivity and noise sensitivity of the proposed method. The experimental results demonstrate that the proposed method exhibits high robustness compared to the state of the art. PMID:26610514

Un cas isolé de tuberculose appendiculaire

PubMed Central

Mountassir, Moujahid; Ennafae, Issam; Kechna, Hicham; Berrada, Samir; El Kandry, Siffedine

2011-01-01

La tuberculose est une affection qui sévit à l’état endémique dans notre pays, elle demeure un problème majeur de santé publique .la tuberculose appendiculaire primitive est une affection très rare. Nous rapportons le cas d'un patient de sexe masculin âgé de 17 ans, admis au service pour une prise en charge d'une douleur de la fosse iliaque droite évoluant dans un contexte fébrile avec conservation de l’état général posant le diagnostic d'une appendicite aigue. Une appendicectomie a été réalisée ; le compte rendu anatomopathologique était en faveur d'une tuberculose appendiculaire isolée. Le patient a été mis sous traitement anti-bacillaire complémentaire pendant neuf mois avec une bonne évolution clinique. Le diagnostic de tuberculose doit être évoqué en premier surtout dans les pays d'endémie tuberculeuse. PMID:22355426

Hémophilie B mineure révélée par une hémorragie cérébrale: à propos d'un cas

PubMed Central

Naji, Abdelhalim; Rkain, Maria; Amrani, Rim; Benajiba, Noufissa

2015-01-01

L'hémorragie intracrânienne (HIC) du nouveau-né à terme est une pathologie rare, leur prévalence est estimée à 2% des naissances vivantes. Les manifestations cliniques sont variables et non spécifique. Les causes d'HIC sont multiples et souvent intriquées, les mécanismes physiopathologiques principaux sont la dysrégulation du débit cérébral, une obstruction des vaisseaux ou une coagulation intravasculaire; ou une lésion directe par traumatisme. Nous rapportons le cas d'un nourrisson d'un mois qui a été admis dans notre service pour prendre en charge des convulsions associées à une pâleur cutanéomuqueuse, suite à laquelle l'examen biologique a mis fortuitement en faveur une hémophilie mineure sur une maladie hémorragique tardive. PMID:26491519

Complete dislocation of the ulnar nerve at the elbow: a protective effect against neuropathy?

PubMed

Leis, A Arturo; Smith, Benn E; Kosiorek, Heidi E; Omejec, Gregor; Podnar, Simon

2017-08-01

Recurrent complete ulnar nerve dislocation has been perceived as a risk factor for development of ulnar neuropathy at the elbow (UNE). However, the role of dislocation in the pathogenesis of UNE remains uncertain. We studied 133 patients with complete ulnar nerve dislocation to determine whether this condition is a risk factor for UNE. In all, the nerve was palpated as it rolled over the medial epicondyle during elbow flexion. Of 56 elbows with unilateral dislocation, UNE localized contralaterally in 17 elbows (30.4%) and ipsilaterally in 10 elbows (17.9%). Of 154 elbows with bilateral dislocation, 26 had UNE (16.9%). Complete dislocation decreased the odds of having UNE by 44% (odds ratio = 0.475; P =  0.028), and was associated with less severe UNE (P = 0.045). UNE occurs less frequently and is less severe on the side of complete dislocation. Complete dislocation may have a protective effect on the ulnar nerve. Muscle Nerve 56: 242-246, 2017. © 2016 Wiley Periodicals, Inc.

Applied estimation for hybrid dynamical systems using perceptional information

NASA Astrophysics Data System (ADS)

Plotnik, Aaron M.

This dissertation uses the motivating example of robotic tracking of mobile deep ocean animals to present innovations in robotic perception and estimation for hybrid dynamical systems. An approach to estimation for hybrid systems is presented that utilizes uncertain perceptional information about the system's mode to improve tracking of its mode and continuous states. This results in significant improvements in situations where previously reported methods of estimation for hybrid systems perform poorly due to poor distinguishability of the modes. The specific application that motivates this research is an automatic underwater robotic observation system that follows and films individual deep ocean animals. A first version of such a system has been developed jointly by the Stanford Aerospace Robotics Laboratory and Monterey Bay Aquarium Research Institute (MBARI). This robotic observation system is successfully fielded on MBARI's ROVs, but agile specimens often evade the system. When a human ROV pilot performs this task, one advantage that he has over the robotic observation system in these situations is the ability to use visual perceptional information about the target, immediately recognizing any changes in the specimen's behavior mode. With the approach of the human pilot in mind, a new version of the robotic observation system is proposed which is extended to (a) derive perceptional information (visual cues) about the behavior mode of the tracked specimen, and (b) merge this dissimilar, discrete and uncertain information with more traditional continuous noisy sensor data by extending existing algorithms for hybrid estimation. These performance enhancements are enabled by integrating techniques in hybrid estimation, computer vision and machine learning. First, real-time computer vision and classification algorithms extract a visual observation of the target's behavior mode. Existing hybrid estimation algorithms are extended to admit this uncertain but discrete observation, complementing the information available from more traditional sensors. State tracking is achieved using a new form of Rao-Blackwellized particle filter called the mode-observed Gaussian Particle Filter. Performance is demonstrated using data from simulation and data collected on actual specimens in the ocean. The framework for estimation using both traditional and perceptional information is easily extensible to other stochastic hybrid systems with mode-related perceptional observations available.

Une masse palpébrale révélant une fistule carotidocaverneuse

PubMed Central

Oulali, Noureddine; Moufid, Fayçal; Khoulali, Mohammed; Sekhsoukh, Rachid; Housni, Brahim; Ghailan, Mohamed Rachid

2012-01-01

Les auteurs rapportent une observation particulière, chez un homme de 48 ans ayant dans ces antécédents un traumatisme crânio-faciale grave il y'a dix ans, qui présente depuis huit mois une masse palpébrale droite, avec une discrète exophtalmie et hémorragie sous conjonctivale, l'angio IRM a permis de confirmer le diagnostique d'une fistule carotidocaverneuse à haut débit, qui est responsable de cette symptomatologie. L'objectif de cet article est de mettre la lumière sur cette pathologie rare, en insistant sur les particularités cliniques de présentation d'une part, et sur le plan thérapeutique d'autre part, en exposant l'intérêt de la radiologie interventionnelle. PMID:23330040

Hémothorax spontané révélant une vascularite de Wegener chez une femme enceinte

PubMed Central

Serhane, Hind; Yassine, Msougar; Amro, Lamyae

2016-01-01

L’hémothorax spontané demeure une pathologie rare. Ses étiologies sont multiples mais restent parfois inconnues. Chez certains patients, la thoracotomie peut être le seul recours pour déterminer son origine. Les vascularites n’ont pas été rapporté comme cause habituelle des hémothorax spontanés. La grossesse ne semble pas avoir d’effet causal, ni aggravant des hémothorax spontanés, ni des vascularites. Nous rapportons une observation assez particulière d’une jeune patiente, présentant au cours de sa grossesse un hémothorax spontané secondaire à une vasularite de type Wegener, diagnostiquée par la biopsie pleurale faite au cours d’une thoracotomie exploratrice et confirmée par le dosage des ANCA. PMID:28154726

Ostéo-arthrite tuberculeuse tarsienne: à propos d’un cas

PubMed Central

Yacoubi, Hicham; Erraji, Moncef; Abdelillah, Rachid; Abbassi, Najib; Abdeljawad, Najib; Daoudi, Abdelkrim

2012-01-01

Nous rapportons le cas d’une patiente de 45 ans sans antécédents médicaux particuliers, qui a présenté une atteinte inflammatoire du pied gauche, sans notion de traumatisme ni de fièvre, avec apparition secondaire d’une fistule cutanée purulente à la face externe du cou de pied. Les radiographies standards et la Tomodensitométrie de la cheville mettaient en évidence une ostéite calcanéenne avec atteinte articulaire subtalienne. Une biopsie chirurgicale associée à une excision des tissus inflammatoires et nécrotiques et l’ablation du trajet fistuleux, ont été réalisées. L’analyse histologique montrait une image de granulome épithélio-giganto-cellulaire avec une nécrose caséeuse et les prélèvements bactériologiques (retrouvaient Mycobacterium tuberculosis. Une chimiothérapie antituberculeuse a été administrée pendant 12 mois. À 24 mois, la patiente ne présentait pas de récidive mais une arthropathie dégénérative secondaire subtalienne. Il nous semble intéressant de rappeler que tout tableau clinique traînant ou toute lésion osseuse suspecte et de présentation atypique doit faire évoquer le diagnostic de tuberculose afin d’éviter des retards de diagnostic. Ceci permet une prise en charge thérapeutique précoce de la pathologie. PMID:22655098

Fistule vesico-sigmoïdienne compliquant une hydatidose intestinale: à propos d'un cas rare

PubMed Central

Lahyani, Mounir; Jabbour, Younes; Karmouni, Tarik; Elkhader, Khalid; Koutani, Abdellatif; Andaloussi, Ahmed Ibn attya

2014-01-01

La fistule colo-vésicale sur une hydatidose sigmoidienne est une entité pathologique exceptionnelle. Nous rapportions une nouvelle observation, ou seront rappelées les principales données diagnostique et thérapeutique de cette affection. PMID:25722790

A New Vision for Chemistry Education Students: Environmental Education

ERIC Educational Resources Information Center

Teksoz, Gaye; Sahin, Elvan; Ertepinar, Hamide

2010-01-01

The present study aimed to determine level of pre-service chemistry teachers' environmental literacy and their perceptions on environmental education. This study was realized during the fall semester of 2006-2007 academic year with the participation of 60 students enrolled in five-year chemistry teacher education program. The data collected by…

Myths, Stereotypes and Self-Perception: The Impact of Albinism on Self-Esteem

ERIC Educational Resources Information Center

Palmer, Carolyn

2007-01-01

Albinism has the potential to affect young people both emotionally and psychologically. Their condition is unique and is surrounded by myths and stereotypes. The unusual appearance of children with oculocutaneous albinism draws attention to them and their vision impairment can impact on their development of social skills and peer relationships. In…

The Library and the Museum Become Tele-vision.

ERIC Educational Resources Information Center

Lanigan, Richard L.

The advent of mass media in the twentieth century creates certain "ruptures," as Michel Foucault would say, in the perceptual world of human beings as they go about the everyday business of coping with a technological culture grounded in human perception as the rule for expression. Foucault proposes that people watch two…

Sustained Attention to Local and Global Target Features Is Different: Performance and Tympanic Membrane Temperature

ERIC Educational Resources Information Center

Helton, William S.; Hayrynen, Lauren; Schaeffer, David

2009-01-01

Vision researchers have investigated the differences between global and local feature perception. No one has, however, examined the role of global and local feature discrimination in sustained attention tasks. In this experiment participants performed a sustained attention task requiring either global or local letter target discriminations or…

Measuring Staff Perceptions of University Identity and Activities: The Mission and Values Inventory

ERIC Educational Resources Information Center

Ferrari, Joseph R.; Velcoff, Jessica

2006-01-01

Higher education institutions need to ascertain whether their stakeholders understand the school's mission, vision, and values. In the present study, the psychometric properties of a mission identity and activity measure were investigated with two staff samples. Using a principal component factor analysis (varimax rotation), respondents in Sample…

Perceptions about Teacher Leadership: Do Teacher Leaders and Administrators Share a Common Ground?

ERIC Educational Resources Information Center

Uribe-Flórez, Lida J.; Al-Rawashdeh, Amneh; Morales, Sara

2014-01-01

In 2010, the Mathematically Connected Communities Leadership Institute for Teachers (MC[superscript 2]-LIFT) started with a vision for preparing teachers to lead the construction of appropriate learning environments in their schools and districts (MC[superscript 2]-Lift Proposal, 2009). During this two-year program, MC[superscript 2]-LIFT prepared…

Quarked!--Adventures in Particle Physics Education

ERIC Educational Resources Information Center

MacDonald, Teresa; Bean, Alice

2009-01-01

Particle physics is a subject that can send shivers down the spines of students and educators alike--with visions of long mathematical equations and inscrutable ideas. This perception, along with a full curriculum, often leaves this topic the road less traveled until the latter years of school. Particle physics, including quarks, is typically not…

Teachers' Perceptions about Addressing Literacy for Students with Vision Impairment

ERIC Educational Resources Information Center

Washington, Samantha C.

2017-01-01

Regular education teachers are sometimes at a disadvantage when required to instruct learners with a visual impairment or other special needs in the classroom. A problem exists with reduced support and training for regular education teachers responsible for meeting literacy needs of students with visual impairment. The purpose of this qualitative…

College-Adult Reading--Past, Present and Future.

ERIC Educational Resources Information Center

Spache, George D.

College-adult reading research trends are discussed. The reading process; the influence of vision, perception, and personality; and program outcomes are noted as major trends of past studies, and a list of mistaken assumptions in these earlier studies is given. Present research shifts to the study of the role of both teacher and student…

Drama as a Tool in Interpretation: Practitioner Perceptions of Its Strengths & Limitations

ERIC Educational Resources Information Center

Adcock, Lynne; Ballantyne, Roy

2007-01-01

Although environmental and heritage interpretation aims to connect humans with their natural and cultural heritage, and has the potential to contribute to a vision of sustainable living, it often falls short of engaging and inspiring its audiences. Some interpreters advocate the use of artistic approaches to create more affective…

Metaphor as a Tool in Educational Leadership Classrooms

ERIC Educational Resources Information Center

Singh, Kathryn

2010-01-01

As students begin credentialing programs, they usually take a basic course on leadership, and we often invite them to reflect on their own perceptions of qualities, vision, mission and effectiveness. In Fall 2008, in my classes, I discovered that students struggled to articulate thoughts on leadership. Many felt unqualified, not having been…

Incorporating Animation Concepts and Principles in STEM Education

ERIC Educational Resources Information Center

Harrison, Henry L., III; Hummell, Laura J.

2010-01-01

Animation is the rapid display of a sequence of static images that creates the illusion of movement. This optical illusion is often called perception of motion, persistence of vision, illusion of motion, or short-range apparent motion. The phenomenon occurs when the eye is exposed to rapidly changing still images, with each image being changed…

Acceptance of the Long Cane by Persons Who Are Blind in South India

ERIC Educational Resources Information Center

Christy, Beula; Nirmalan, Praveen K.

2006-01-01

Human beings both sense the immediate environment and navigate beyond the immediately perceptible environment to find their way (Golledge, Loomis, Klatzky, Flury, & Yang, 1991; Golledge, Klatzky, & Loomis, 1996; Blasch, Wiener, & Welsh, 1997). People who are visually impaired (that is, are blind or have low vision) often lack the…

Visual adaptation and face perception

PubMed Central

Webster, Michael A.; MacLeod, Donald I. A.

2011-01-01

The appearance of faces can be strongly affected by the characteristics of faces viewed previously. These perceptual after-effects reflect processes of sensory adaptation that are found throughout the visual system, but which have been considered only relatively recently in the context of higher level perceptual judgements. In this review, we explore the consequences of adaptation for human face perception, and the implications of adaptation for understanding the neural-coding schemes underlying the visual representation of faces. The properties of face after-effects suggest that they, in part, reflect response changes at high and possibly face-specific levels of visual processing. Yet, the form of the after-effects and the norm-based codes that they point to show many parallels with the adaptations and functional organization that are thought to underlie the encoding of perceptual attributes like colour. The nature and basis for human colour vision have been studied extensively, and we draw on ideas and principles that have been developed to account for norms and normalization in colour vision to consider potential similarities and differences in the representation and adaptation of faces. PMID:21536555

Vision after 53 years of blindness.

PubMed

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.

Visual acuity in young elite motorsport athletes: a preliminary report.

PubMed

Schneiders, Anthony G; Sullivan, S John; Rathbone, Emma J; Louise Thayer, A; Wallis, Laura M; Wilson, Alexandra E

2010-05-01

To determine whether elite motorsport athletes demonstrate superior levels of Visual Acuity than age and sex-matched controls. A cross-sectional observational study. A University vision and balance laboratory. Young male motorsport athletes from the New Zealand Elite Motorsport Academy and healthy age and sex-matched controls. Vision performance tests comprising; Static Visual Acuity (SVA), Dynamic Visual Acuity (DVA), Gaze Stabilization Test (GST), and the Perception Time Test (PTT). Motorsport athletes demonstrated superior visual acuity compared to age and sex-matched controls for all measures, and while this was not statistically significant for SVA, GST and DVA, it reached statistical significance for the PTT (p

Visual adaptation and face perception.

PubMed

Webster, Michael A; MacLeod, Donald I A

2011-06-12

The appearance of faces can be strongly affected by the characteristics of faces viewed previously. These perceptual after-effects reflect processes of sensory adaptation that are found throughout the visual system, but which have been considered only relatively recently in the context of higher level perceptual judgements. In this review, we explore the consequences of adaptation for human face perception, and the implications of adaptation for understanding the neural-coding schemes underlying the visual representation of faces. The properties of face after-effects suggest that they, in part, reflect response changes at high and possibly face-specific levels of visual processing. Yet, the form of the after-effects and the norm-based codes that they point to show many parallels with the adaptations and functional organization that are thought to underlie the encoding of perceptual attributes like colour. The nature and basis for human colour vision have been studied extensively, and we draw on ideas and principles that have been developed to account for norms and normalization in colour vision to consider potential similarities and differences in the representation and adaptation of faces.

Reframing the action and perception dissociation in DF: haptics matters, but how?

PubMed

Whitwell, Robert L; Buckingham, Gavin

2013-02-01

Goodale and Milner's (1992) "vision-for-action" and "vision-for-perception" account of the division of labor between the dorsal and ventral "streams" has come to dominate contemporary views of the functional roles of these two pathways. Nevertheless, some lines of evidence for the model remain controversial. Recently, Thomas Schenk reexamined visual form agnosic patient DF's spared anticipatory grip scaling to object size, one of the principal empirical pillars of the model. Based on this new evidence, Schenk rejects the original interpretation of DF's spared ability that was based on segregated processing of object size and argues that DF's spared grip scaling relies on haptic feedback to calibrate visual egocentric cues that relate the posture of the hand to the visible edges of the goal-object. However, a careful consideration of the tasks that Schenk employed reveals some problems with his claim. We suspect that the core issues of this controversy will require a closer examination of the role that cognition plays in the operation of the dorsal and ventral streams in healthy controls and in patient DF.

Gamut relativity: a new computational approach to brightness and lightness perception.

PubMed

Vladusich, Tony

2013-01-09

This article deconstructs the conventional theory that "brightness" and "lightness" constitute perceptual dimensions corresponding to the physical dimensions of luminance and reflectance, and builds in its place the theory that brightness and lightness correspond to computationally defined "modes," rather than dimensions, of perception. According to the theory, called gamut relativity, "blackness" and "whiteness" constitute the perceptual dimensions (forming a two-dimensional "blackness-whiteness" space) underlying achromatic color perception (black, white, and gray shades). These perceptual dimensions are postulated to be related to the neural activity levels in the ON and OFF channels of vision. The theory unifies and generalizes a number of extant concepts in the brightness and lightness literature, such as simultaneous contrast, anchoring, and scission, and quantitatively simulates several challenging perceptual phenomena, including the staircase Gelb effect and the effects of task instructions on achromatic color-matching behavior, all with a single free parameter. The theory also provides a new conception of achromatic color constancy in terms of the relative distances between points in blackness-whiteness space. The theory suggests a host of striking conclusions, the most important of which is that the perceptual dimensions of vision should be generically specified according to the computational properties of the brain, rather than in terms of "reified" physical dimensions. This new approach replaces the computational goal of estimating absolute physical quantities ("inverse optics") with the goal of computing object properties relatively.

Color vision in ADHD: part 2--does attention influence color perception?

PubMed

Kim, Soyeon; Al-Haj, Mohamed; Fuller, Stuart; Chen, Samantha; Jain, Umesh; Carrasco, Marisa; Tannock, Rosemary

2014-10-24

To investigate the impact of exogenous covert attention on chromatic (blue and red) and achromatic visual perception in adults with and without Attention Deficit Hyperactivity Disorder (ADHD). Exogenous covert attention, which is a transient, automatic, stimulus-driven form of attention, is a key mechanism for selecting relevant information in visual arrays. 30 adults diagnosed with ADHD and 30 healthy adults, matched on age and gender, performed a psychophysical task designed to measure the effects of exogenous covert attention on perceived color saturation (blue, red) and contrast sensitivity. The effects of exogenous covert attention on perceived blue and red saturation levels and contrast sensitivity were similar in both groups, with no differences between males and females. Specifically, exogenous covert attention enhanced the perception of blue saturation and contrast sensitivity, but it had no effect on the perception of red saturation. The findings suggest that exogenous covert attention is intact in adults with ADHD and does not account for the observed impairments in the perception of chromatic (blue and red) saturation.

Interaction between contours and eye movements in the perception of afterimages: A test of the signal ambiguity theory.

PubMed

Powell, Georgie; Sumner, Petroc; Harrison, James J; Bompas, Aline

2016-05-01

An intriguing property of afterimages is that conscious experience can be strong, weak, or absent following identical stimulus adaptation. Previously we suggested that postadaptation retinal signals are inherently ambiguous, and therefore the perception they evoke is strongly influenced by cues that increase or decrease the likelihood that they represent real objects (the signal ambiguity theory). Here we provide a more definitive test of this theory using two cues previously found to influence afterimage perception in opposite ways and plausibly at separate loci of action. However, by manipulating both cues simultaneously, we found that their effects interacted, consistent with the idea that they affect the same process of object interpretation rather than being independent influences. These findings bring contextual influences on afterimages into more general theories of cue combination, and we suggest that afterimage perception should be considered alongside other areas of vision science where cues are found to interact in their influence on perception.

Seeing a haptically explored face: visual facial-expression aftereffect from haptic adaptation to a face.

PubMed

Matsumiya, Kazumichi

2013-10-01

Current views on face perception assume that the visual system receives only visual facial signals. However, I show that the visual perception of faces is systematically biased by adaptation to a haptically explored face. Recently, face aftereffects (FAEs; the altered perception of faces after adaptation to a face) have been demonstrated not only in visual perception but also in haptic perception; therefore, I combined the two FAEs to examine whether the visual system receives face-related signals from the haptic modality. I found that adaptation to a haptically explored facial expression on a face mask produced a visual FAE for facial expression. This cross-modal FAE was not due to explicitly imaging a face, response bias, or adaptation to local features. Furthermore, FAEs transferred from vision to haptics. These results indicate that visual face processing depends on substrates adapted by haptic faces, which suggests that face processing relies on shared representation underlying cross-modal interactions.

A new look at emotion perception: Concepts speed and shape facial emotion recognition.

PubMed

Nook, Erik C; Lindquist, Kristen A; Zaki, Jamil

2015-10-01

Decades ago, the "New Look" movement challenged how scientists thought about vision by suggesting that conceptual processes shape visual perceptions. Currently, affective scientists are likewise debating the role of concepts in emotion perception. Here, we utilized a repetition-priming paradigm in conjunction with signal detection and individual difference analyses to examine how providing emotion labels-which correspond to discrete emotion concepts-affects emotion recognition. In Study 1, pairing emotional faces with emotion labels (e.g., "sad") increased individuals' speed and sensitivity in recognizing emotions. Additionally, individuals with alexithymia-who have difficulty labeling their own emotions-struggled to recognize emotions based on visual cues alone, but not when emotion labels were provided. Study 2 replicated these findings and further demonstrated that emotion concepts can shape perceptions of facial expressions. Together, these results suggest that emotion perception involves conceptual processing. We discuss the implications of these findings for affective, social, and clinical psychology. (c) 2015 APA, all rights reserved).

A model of color vision with a robot system

NASA Astrophysics Data System (ADS)

Wang, Haihui

2006-01-01

In this paper, we propose to generalize the saccade target method and state that perceptual stability in general arises by learning the effects one's actions have on sensor responses. The apparent visual stability of color percept across saccadic eye movements can be explained by positing that perception involves observing how sensory input changes in response to motor activities. The changes related to self-motion can be learned, and once learned, used to form stable percepts. The variation of sensor data in response to a motor act is therefore a requirement for stable perception rather than something that has to be compensated for in order to perceive a stable world. In this paper, we have provided a simple implementation of this sensory-motor contingency view of perceptual stability. We showed how a straightforward application of the temporal difference enhancement learning technique yielding color percepts that are stable across saccadic eye movements, even though the raw sensor input may change radically.

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

PubMed

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 retinopathy.

Conception, elaboration et mise a l'essai d'un simulateur interactif permettant une approche modelisante: Application aux lois de la genetique mendelienne

NASA Astrophysics Data System (ADS)

Lasri, Abdel-Halim

Dans cette recherche-developpement, nous avons concu, developpe et mis a l'essai un simulateur interactif pour favoriser l'apprentissage des lois probabilistes impliqees dans la genetique mendelienne. Cet environnement informatise devra permettre aux etudiants de mener des experiences simulees, utilisant les statistiques et les probebilites comme outils mathematiques pour modeliser le phenomene de la transmission des caracteres hereditaires. L'approche didactique est essentiellement orientee vers l'utilisation des methodes quantitatives impliquees dans l'experimentation des facteurs hereditaires. En incorporant au simulateur le principe de la "Lunette cognitive" de Nonnon (1986), l'etudiant fut place dans une situation ou il a pu synchroniser la perception de la representation iconique (concrete) et symbolique (abstraite) des lois probabilistes de Mendel. A l'aide de cet environnement, nous avons amene l'etudiant a identifier le(s) caractere(s) hereditaire(s) des parents a croiser, a predire les frequences phenotypiques probables de la descendance issue du croisement, a observer les resultats statistiques et leur fluctuation au niveau de l'histogramme des frequences, a comparer ces resultats aux predictions anticipees, a interpreter les donnees et a selectionner en consequence d'autres experiences a realiser. Les etapes de l'approche inductive sont privilegiees du debut a la fin des activites proposees. L'elaboration, du simulateur et des documents d'accompagnement, a ete concue a partir d'une vingtaine de principes directeurs et d'un modele d'action. Ces principes directeurs et le modele d'action decoulent de considerations theoriques psychologiques, didactiques et technologiques. La recherche decrit la structure des differentes parties composant le simulateur. L'architecture de celui-ci est construite autour d'une unite centrale, la "Principale", dont les liens et les ramifications avec les autres unites confere a l'ensemble du simulateur sa souplesse et sa facilite d'utilisation. Le simulateur "Genetique", a l'etat de prototype, et la documentation qui lui est afferente ont ete soumis a deux mises a l'essai: l'une fonctionnelle, l'autre empirique. La mise a l'essai fonctionnelle, menee aupres d'un groupe d'enseignants experts, a permis d'identifier les lacunes du materiel elabore afin de lui apporter les reajustements qui s'imposaient. La mise a l'essai empirique, conduite par un groupe de onze (11) etudiants de niveau secondaire, avait pour but, d'une part, de tester la facilite d'utilisation du simulateur "Genetique" ainsi que les documents d'accompagnement et, d'autre part, de verifier si les participants retiraient des avantages pedagogiques de cet environnement. Trois techniques furent exploitees pour recolter les donnees de la mise a l'essai empirique. L'analyse des resultats a permis de faire un retour critique sur les productions concretes de cette recherche et d'apporter les modifications necessaires tant au simulateur qu'aux documents d'accompagnement. Cette analyse a permis egalement de conclure que notre simulateur interactif favorise une approche inductive permettant aux etudiants de s'approprier les lois probabilistes de Mendel. Enfin, la conclusion degage des pistes de recherches destinees aux etudes ulterieures, plus particulierement celles qui s'interessent a developper des simulateurs, afin d'integrer a ceux-ci des representations concretes et abstraites presentees en temps reel. Les disquettes du simulateur "Genetique" et les documents d'accompagnement sont annexes a la presente recherche.

Vision, knowledge, and assertion.

PubMed

Turri, John

2016-04-01

I report two experiments studying the relationship among explicit judgments about what people see, know, and should assert. When an object of interest was surrounded by visibly similar items, it diminished people's willingness to judge that an agent sees, knows, and should tell others that it is present. This supports the claim, made by many philosophers, that inhabiting a misleading environment intuitively decreases our willingness to attribute perception and knowledge. However, contrary to stronger claims made by some philosophers, inhabiting a misleading environment does not lead to the opposite pattern whereby people deny perception and knowledge. Causal modeling suggests a specific psychological model of how explicit judgments about perception, knowledge, and assertability are made: knowledge attributions cause perception attributions, which in turn cause assertability attributions. These findings advance understanding of how these three important judgments are made, provide new evidence that knowledge is the norm of assertion, and highlight some important subtleties in folk epistemology. Copyright © 2016 Elsevier Inc. All rights reserved.

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

PubMed

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.

Access to low-vision rehabilitation services: barriers and enablers.

PubMed

Matti, Albert I; Pesudovs, Konrad; Daly, Andrew; Brown, Margaret; Chen, Celia S

2011-03-01

The current mismatch between the need for and uptake of low-vision services has been attributed to various barriers including different service delivery models and referral pathways. This study evaluates the referral pathway and low-vision service provision of the Royal Society for the Blind (RSB) in South Australia. All new referrals from the 2008-2009 financial year to the RSB were reviewed. Initially, patients were contacted by a triage officer within one week of referral. Initial appointments were made in the Low Vision Clinic with a multidisciplinary team. Reasons for declining the appointment or non-attendance were tracked via telephone. There were 1116 patients referred over a 12-month period and 1082 (97 per cent) were reviewed in the Low Vision Clinic. Most attendees (92 per cent) lived within 50 kilometres of the clinic. There were 34 referred patients, who declined or did not attend the assessment. All non-attendees also lived within 50 kilometres of the Low Vision Centre. Concurrent major health problems (27 per cent) and patients not feeling the need for low-vision rehabilitation (27 per cent) were the most common reasons for not accessing the service. Only 125 patients (11.6 per cent) accessed volunteer transport services and only 24 patients (2.2 per cent) needed an interpreter service. The attendance rate is significantly higher than in other published studies. The distance to travel or transport difficulties were not significant barriers. Patient perception that either the service was not required or would not help them was the main barrier. The referral and triage process appeared to be a major enabler of low-vision service uptake. © 2010 The Authors. Clinical and Experimental Optometry © 2010 Optometrists Association Australia.

Emergent risk factors associated with eyeball loss and ambulatory vision loss after globe injuries.

PubMed

Hyun Lee, Seung; Ahn, Jae Kyoun

2010-07-01

The objective of this study was to evaluate risk factors associated with eyeball loss and ambulatory vision loss on emergent examination of patients with ocular trauma. We reviewed the medical records of 1,875 patients hospitalized in a single tertiary referral center between January 2003 and December 2007. Emergent examinations included a history of trauma, elapsed time between injury and hospital arrival, visible intraocular tissues, and initial visual acuity (VA) using a penlight. The main outcome measures were ocular survival and ambulatory vision survival (>20/200) at 1 year after trauma using univariate and multivariate regression analysis. The ocular trauma scores were significantly higher in open globe injuries than in closed globe injuries (p < 0.01). In open globe injuries, initial VA less than light perception (LP) and a history of golf ball injury were the significant risk factors associated with eyeball loss. Elapsed time more than 12 hours and visible intraocular tissues were the significant risk factors associated with ambulatory vision loss. The most powerful predictor of eyeball loss and ambulatory vision loss was eyeball rupture. In closed globe injuries, there were no significant risk factors of eyeball loss, whereas initial vision less than LP and the presence of relative afferent pupillary defect were the significant risk factors associated with ambulatory vision loss. An initial VA less than LP using a penlight, a history of golf ball injury, and elapsed time more than 12 hours between ocular trauma and hospital arrival were associated with eyeball loss and ambulatory vision loss. Physicians should bear these factors in mind so that they can more effectively counsel patients with such injuries.

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

NASA Astrophysics Data System (ADS)

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.

On the functional relevance of frontal cortex for passive and voluntarily controlled bistable vision.

PubMed

de Graaf, Tom A; de Jong, Maartje C; Goebel, Rainer; van Ee, Raymond; Sack, Alexander T

2011-10-01

In bistable vision, one constant ambiguous stimulus leads to 2 alternating conscious percepts. This perceptual switching occurs spontaneously but can also be influenced through voluntary control. Neuroimaging studies have reported that frontal regions are activated during spontaneous perceptual switches, leading some researchers to suggest that frontal regions causally induce perceptual switches. But the opposite also seems possible: frontal activations may themselves be caused by spontaneous switches. Classically implicated in attentional processes, these same regions are also candidates for the origins of voluntary control over bistable vision. Here too, it remains unknown whether frontal cortex is actually functionally relevant. It is even possible that spontaneous perceptual switches and voluntarily induced switches are mediated by the same top-down mechanisms. To directly address these issues, we here induced "virtual lesions," with transcranial magnetic stimulation, in frontal, parietal, and 2 lower level visual cortices using an established ambiguous structure-from-motion stimulus. We found that dorsolateral prefrontal cortex was causally relevant for voluntary control over perceptual switches. In contrast, we failed to find any evidence for an active role of frontal cortex in passive bistable vision. Thus, it seems the same pathway used for willed top-down modulation of bistable vision is not used during passive bistable viewing.

Increased conspicuousness can explain the match between visual sensitivities and blue plumage colours in fairy-wrens.

PubMed

Delhey, Kaspar; Hall, Michelle; Kingma, Sjouke A; Peters, Anne

2013-01-07

Colour signals are expected to match visual sensitivities of intended receivers. In birds, evolutionary shifts from violet-sensitive (V-type) to ultraviolet-sensitive (U-type) vision have been linked to increased prevalence of colours rich in shortwave reflectance (ultraviolet/blue), presumably due to better perception of such colours by U-type vision. Here we provide the first test of this widespread idea using fairy-wrens and allies (Family Maluridae) as a model, a family where shifts in visual sensitivities from V- to U-type eyes are associated with male nuptial plumage rich in ultraviolet/blue colours. Using psychophysical visual models, we compared the performance of both types of visual systems at two tasks: (i) detecting contrast between male plumage colours and natural backgrounds, and (ii) perceiving intraspecific chromatic variation in male plumage. While U-type outperforms V-type vision at both tasks, the crucial test here is whether U-type vision performs better at detecting and discriminating ultraviolet/blue colours when compared with other colours. This was true for detecting contrast between plumage colours and natural backgrounds (i), but not for discriminating intraspecific variability (ii). Our data indicate that selection to maximize conspicuousness to conspecifics may have led to the correlation between ultraviolet/blue colours and U-type vision in this clade of birds.

The neural monitoring of visceral inputs, rather than attention, accounts for first-person perspective in conscious vision.

PubMed

Tallon-Baudry, Catherine; Campana, Florence; Park, Hyeong-Dong; Babo-Rebelo, Mariana

2018-05-01

Why should a scientist whose aim is to unravel the neural mechanisms of perception consider brain-body interactions seriously? Brain-body interactions have traditionally been associated with emotion, effort, or stress, but not with the "cold" processes of perception and attention. Here, we review recent experimental evidence suggesting a different picture: the neural monitoring of bodily state, and in particular the neural monitoring of the heart, affects visual perception. The impact of spontaneous fluctuations of neural responses to heartbeats on visual detection is as large as the impact of explicit manipulations of spatial attention in perceptual tasks. However, we propose that the neural monitoring of visceral inputs plays a specific role in conscious perception, distinct from the role of attention. The neural monitoring of organs such as the heart or the gut would generate a subject-centered reference frame, from which the first-person perspective inherent to conscious perception can develop. In this view, conscious perception results from the integration of visual content with first-person perspective. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

[The development of the skin-optical perception of color and images in blind schoolchildren on an "internal visual screen"].

PubMed

Mizrakhi, V M; Protsiuk, R G

2000-03-01

In profound impairement of vision the function of colour and seen objects perception is absent, with the person being unable to orient himself in space. The uncovered sensory sensations of colour allowed their use in training the blind in recognizing the colour of paper, fabric, etc. Further study in those having become blind will, we believe, help in finding eligible people and relevant approaches toward educating the blind, which will make for development of the trainee's ability to recognize images on the "inner visual screen".

Le pronostic statural après une pseudo-puberté précoce par déficit en 11ß hydroxylase chez une fille de 7 ans: à propos d'un cas avec revue de la literature

PubMed Central

Latrech, Hanane; Gaouzi, Ahmed

2015-01-01

L'hyperplasie congénitale des surrénales par déficit en 11ß hydroxylase se voit dans 5 à 10% des cas et est diagnostiquée, habituellement, devant des signes de virilisation d'un nouveau né ou d'un fœtus 46 XX et plus tard devant une HTA avec une hypokaliémie. Le pronostic de taille chez ces patients est très souvent compromis. Nous rapportons le cas d'un déficit en 11ß hydroxylase chez une enfant âgée de 7 ans révélé par une pseudo- puberté précoce traitée par hydrocortisone. La survenue d'une puberté précoce centrale complique encore plus la situation par la mise en jeu du pronostic de taille finale et nécessitant une prise en charge thérapeutique particulière. PMID:26113905

Kyste hydatique mammaire primitive

PubMed Central

Boufettal, Houssine; Samouh, Naïma

2015-01-01

La localisation mammaire du kyste hydatique est exceptionnelle. De ce fait, le diagnostic est difficile avant l'examen anatomopathologique. Nous rapportons une observation d'un cas de kyste hydatique du sein chez une femme de 32 ans, qui consultait pour un nodule du sein, dont l'imagerie montrait une lésion en rétro-aréolaire du sein gauche, homogène, ovalaire et de contours réguliers. L'examen anatomopathologique objectivait un kyste hydatique à localisation mammaire. Les suites opératoires étaient simples. L'hydatidose est une maladie ubiquitaire, pouvant atteindre tous les organes. Le diagnostic peut être évoqué devant une masse kystique du sein avec des aspects très évocateurs à l'imagerie. La confirmation du diagnostic n'est confirmée qu'après une cytoponction ou une chirurgie d'exérèse qui réalise le traitement de cette pathologique. La négativité du bilan d'extension hydatique permet de retenir une localisation primitive de l’échinococcose. PMID:26185575

Role of the treating surgeon in the consent process for elective refractive surgery.

PubMed

Schallhorn, Steven C; Hannan, Stephen J; Teenan, David; Schallhorn, Julie M

2016-01-01

To compare patient's perception of consent quality, clinical and quality-of-life outcomes after laser vision correction (LVC) and refractive lens exchange (RLE) between patients who met their treating surgeon prior to the day of surgery (PDOS) or on the day of surgery (DOS). Retrospective, comparative case series. Optical Express, Glasgow, UK. Patients treated between October 2015 and June 2016 (3972 LVC and 979 RLE patients) who attended 1-day and 1-month postoperative aftercare and answered a questionnaire were included in this study. All patients had a thorough preoperative discussion with an optometrist, watched a video consent, and were provided with written information. Patients then had a verbal discussion with their treating surgeon either PDOS or on the DOS, according to patient preference. Preoperative and 1-month postoperative visual acuity, refraction, preoperative, 1-day and 1-month postoperative questionnaire were compared between DOS and PDOS patients. Multivariate regression model was developed to find factors associated with patient's perception of consent quality. Preoperatively, 8.0% of LVC and 17.1% of RLE patients elected to meet their surgeon ahead of the surgery day. In the LVC group, 97.5% of DOS and 97.2% of PDOS patients indicated they were properly consented for surgery ( P =0.77). In the RLE group, 97.0% of DOS and 97.0% of PDOS patients stated their consent process for surgery was adequate ( P =0.98). There was no statistically significant difference between DOS and PDOS patients in most of the postoperative clinical or questionnaire outcomes. Factors predictive of patient's satisfaction with consent quality were postoperative satisfaction with vision (46.7% of explained variance), difficulties with night driving, close-up vision or outdoor/sports activities (25.4%), visual phenomena (12.2%), dry eyes (7.5%), and patient's satisfaction with surgeon's care (8.2%). Perception of quality of consent was comparable between patients that elected to meet the surgeon PDOS, and those who did not.

Anomalie d’émergence radiculaire par racine conjointe S1: à propos d'un cas

PubMed Central

Kessely, Yannick Canton; Sakho, Maguette Gaye; Fondo, Alidji; Daisy, Akerey Diop; Thiam, Aley; Sakho, Youssoupha

2015-01-01

De découverte per-opératoire pour hernie discale, les anomalies d’émergence radiculaires constituent une entité rare. La présentation clinique est généralement identique à celle d'une radiculopathie. Nous rapportons le cas d'un patient âgé de 35 ans présentant une sciatique droite S1 hyperalgique rebelle aux multiples médications. L'IRM du rachis lombo-sacré avait mis en évidence une discopathie protrusive de petit volume en L5 S1 droite et un aspect de grosse racine ou de kyste de Tarlov au niveau de l’émergence droite de S1. Une fenestration inter lamaire L5-S1 droite avec une ablation du ligament jaune a montré une émergence radiculaire double au niveau de l'espace retro-discal. Un geste de foraminostomie a été réalisé sans discectomie. L’évolution a très favorable avec une rétrocession dès le lendemain. L'analyse pré-opératoire fine et rigoureuse de l'imagerie est indispensable. Une bonne libération améliore l’état clinique du patient. Y penser en cas de sciatique hyperalgique sans Lasègue. PMID:26113909

Pseudotumeur cardiaque révélant une maladie de Behçet

PubMed Central

Nya, Fouad; Abdou, Abdessamad; Bamous, Mehdi; Moutakiallah, Younes; Atmani, Noureddine; Seghrouchni, Aniss; Houssa, Mahdi Ait; Boulahya, Abdellatif

2017-01-01

La thrombose intracardiaque est une complication rare de la maladie de Behçet (MB), qui peut se présenter comme une tumeur intracardiaque. Sa découverte précède, dans la moitié des cas, le diagnostic de MB. La mortalité élevée peut être en rapport avec des complications post-chirurgicales et/ou une atteinte associée des artères pulmonaires. Nous rapportons l’observation d’un jeune patient de 29 ans, aux antécédents d’aphtose bipolaire, qui a bénéficie d’une intervention chirurgicale après la découverte d’une tumeur de l’atrium et du ventricule droits. Il s’agissait d’un thrombus à l’examen anatomopathologique et dans les suites opératoires nous avons diagnostiqué une MB. L’évolution a été favorable sous traitement médical associant une corticothérapie, de la colchicine et des antivitamines K (AVK). La découverte d’une masse intracardiaque chez un sujet jeune doit faire évoquer le diagnostic de thrombus cardiaque et de maladie de Behçet, même en l’absence de facteur ethnique ou géographique prédisposant. PMID:28533874

Prevalence of Color Vision Deficiency and its Correlation with Amblyopia and Refractive Errors among Primary School Children.

PubMed

Rajavi, Zhale; Sabbaghi, Hamideh; Baghini, Ahmad Shojaei; Yaseri, Mehdi; Sheibani, Koroush; Norouzi, Ghazal

2015-01-01

To determine the prevalence of color vision deficiency (CVD) and its correlation with amblyopia and refractive errors among primary school children. In this population-based cross-sectional study, 2160 children were selected from 36 primary schools; 60 students were from each school (10 students in each grade), with equal sex distribution. A complete eye examination including refraction using a photorefractometer, determination of visual acuity (VA) and color vision using a Yang vision tester, and evaluation of ocular media opacity using a direct ophthalmoscope was performed. Children who could not answer at least 4 plates of the Ishihara color test were considered as color vision deficient subjects. Amblyopia was determined if pinhole VA was worse than 0.3 LogMAR (equal to 20/40). The prevalence of CVD was 2.2% (95% CI: 1.5% to 3%) which was higher in male subjects (37 [3.5%] boys vs. 11 [1.0%] girls, P < 0.001). Mean VA was lower among students with CVD as compared to normal color vision children (P = 0.035) and amblyopia was observed in 8.3% (95% CI: 0.2% to 16.4%) of patients with CVD versus 2.1% (95% CI: 1.5% to 2.08%) of children with normal color vision perception (P = 0.005). A statistically significant correlation between lower VA and CVD was observed (P = 0.023). Although CVD was correlated with lower VA and amblyopia, there was no relationship between CVD and the type of amblyopia, refractive error, anisometropia or strabismus.

La dysplasie fibreuse: état des lieux

PubMed Central

Akasbi, Nessrine; Abourazzak, Fatima Ezzahra; Talbi, Sofia; Tahiri, Latifa; Harzy, Taoufik

2015-01-01

La dysplasie fibreuse des os est une affection osseuse bénigne congénitale mais non héréditaire, où l'os normal est remplacé par un tissu fibreux renfermant une ostéogenèse immature. Elle est due à une mutation du gène GNAS 1sur le chromosome 20q13, une mutation activatrice de la sous-unité α de la protéine G. C'est une pathologie qui est le plus souvent silencieuse, de découverte fortuite sur une radiographie standard ou révélée par une douleur osseuse ou une fracture pathologique. L'imagerie et l'histologie, quand elle est nécessaire, permettent d’établir le diagnostic. Bien qu'il ne s'agisse pas d'une tumeur, elle est souvent classée dans la catégorie des tumeurs osseuses bénignes pour des raisons de diagnostic différentiel radiographique et anatomopathologique. Elle peut être monostotique ou polyostotique. L'approche thérapeutique est essentiellement symptomatique. Quelques publications récentes ont suggéré l'intérêt majeur d'un bisphosphonate, en particulier le pamidronate, qui diminuerait les douleurs et stimulerait une reminéralisation progressive des zones ostéolytiques chez les patients traités. D'autres traitements tels que la thérapie ciblée sont en cours d’évaluation. PMID:26401215

Méningiome en plaque sphéno-orbitaire: à propos d'un cas avec revue de la littérature

PubMed Central

Abdellaoui, Meriem; Andaloussi, Idriss Benatiya; Tahri, Hicham

2015-01-01

Le méningiome intra osseux est une variété des méningiomes ectopiques dans lequel les cellules méningothéliales envahissent la paroi osseuse et entraînent une hyperostose. Le méningiome en plaque, variante macroscopique des méningiomes intra osseux, est une tumeur rare et survient fréquemment au niveau de la région sphéno-orbitaire ce qui le confond avec les tumeurs osseuses primitives. Nous rapportons le cas d'une patiente de 50 ans qui présente une exophtalmie avec cécité unilatérale gauche d'installation progressive depuis un an. L'examen trouve une exophtalmie axile, indolore et non réductible ainsi qu'une limitation de la motilité oculaire dans tous les sens du regard. La palpation montre une masse temporale gauche dure et adhérente à l'os. L'examen du fond d’œil trouve un œdème papillaire gauche. Le scanner montre une lésion ostéocondensante temporo-sphéno-orbitaire gauche avec envahissement locorégional. Le diagnostic préopératoire fut une tumeur osseuse essentiellement maligne primitive ou secondaire. L’étude histologique a révélée un méningiome meningothélial de type en plaque. La patiente a bénéficié d'une exérèse avec reconstruction chirurgicale. Aucune récidive n'a été notée après 1 an de recul. PMID:26327996

Métastase pleurale et pulmonaire d’une polyadénofibromatose dégénéréé: à propos d’un cas

PubMed Central

El Hachimi, Kawtar; Benjelloun, Hanane; Zaghba, Nahid; Yassine, Najiba

2017-01-01

La polyadénofibromatose ou l’adénofibromatose est définie par la présence d’au moins 3 adénofibromes, uni ou bilatéraux atteignant une taille importante responsable de troubles trophiques. Nous rapportons une observation colligée au service des maladies respiratoires du Centre Hospitalier Universitaire Ibn Rochd de Casablanca. Il s’agit d’une patiente âgée de 46ans, suivie depuis l’âge de 30 ans pour une adénofibromatose bilatérale opérée à 4 reprises. Suite à un bilan préopératoire d’une mastectomie bilatérale, une radio du thorax a été réalisée objectivant un hémithorax droit opaque avec refoulement des éléments du médiastin. L’examen clinique retrouvait un syndrome d’épanchement liquidien de l’hémithorax droit et une adénopathie cervicale sus claviculaire gauche. La ponction biopsie pleurale confirmait la localisation pleurale d’un carcinome peu différencié et invasif compatible avec une origine mammaire. La bronchoscopie après évacuation pleurale objectivait un aspect infiltré de tout l’arbre bronchique, dont les biopsies concluaient au même résultat anatomopathologique. Le traitement préconisé était une polychimiothérapie. L’évolution était marquée par l’apparition de métastases hépatiques. A travers cette observation, nous concluons que les adénofibromes nécessitent une surveillance régulière vu le risque de dégénérescence vers le cancer du sein qui est une cause fréquente de métastases pleuropulmonaires. PMID:29515733

Degradation of labial information modifies audiovisual speech perception in cochlear-implanted children.

PubMed

Huyse, Aurélie; Berthommier, Frédéric; Leybaert, Jacqueline

2013-01-01

The aim of the present study was to examine audiovisual speech integration in cochlear-implanted children and in normally hearing children exposed to degraded auditory stimuli. Previous studies have shown that speech perception in cochlear-implanted users is biased toward the visual modality when audition and vision provide conflicting information. Our main question was whether an experimentally designed degradation of the visual speech cue would increase the importance of audition in the response pattern. The impact of auditory proficiency was also investigated. A group of 31 children with cochlear implants and a group of 31 normally hearing children matched for chronological age were recruited. All children with cochlear implants had profound congenital deafness and had used their implants for at least 2 years. Participants had to perform an /aCa/ consonant-identification task in which stimuli were presented randomly in three conditions: auditory only, visual only, and audiovisual (congruent and incongruent McGurk stimuli). In half of the experiment, the visual speech cue was normal; in the other half (visual reduction) a degraded visual signal was presented, aimed at preventing lipreading of good quality. The normally hearing children received a spectrally reduced speech signal (simulating the input delivered by the cochlear implant). First, performance in visual-only and in congruent audiovisual modalities were decreased, showing that the visual reduction technique used here was efficient at degrading lipreading. Second, in the incongruent audiovisual trials, visual reduction led to a major increase in the number of auditory based responses in both groups. Differences between proficient and nonproficient children were found in both groups, with nonproficient children's responses being more visual and less auditory than those of proficient children. Further analysis revealed that differences between visually clear and visually reduced conditions and between groups were not only because of differences in unisensory perception but also because of differences in the process of audiovisual integration per se. Visual reduction led to an increase in the weight of audition, even in cochlear-implanted children, whose perception is generally dominated by vision. This result suggests that the natural bias in favor of vision is not immutable. Audiovisual speech integration partly depends on the experimental situation, which modulates the informational content of the sensory channels and the weight that is awarded to each of them. Consequently, participants, whether deaf with cochlear implants or having normal hearing, not only base their perception on the most reliable modality but also award it an additional weight.

Une rare cause de sciatique non discale: une polyarthrite rhumatoïde

PubMed Central

Akasbi, Nessrine; Abourazzak, Fatima Ezzahra; Harzy, Taoufik

2014-01-01

La polyarthrite rhumatoïde est le rhumatisme inflammatoire chronique le plus fréquent. Ses complications neurologiques sont dominées par les neuropathies périphériques, cliniquement asymptomatiques, mais peuvent être détectées sur l’électromyogramme (EMG). Nous rapportons l'observation d'une patiente qui a présenté une neuropathie sensitivo-motrice aux deux membres inférieurs associée à une sciatique de topographie L5 d'origine rhumatoïde. PMID:25709734

Pathomimie de l'enfant: à propos d'une observation

PubMed Central

Abilkassem, Rachid; Dini, Nezha; Ourai, Hakim; Kmari, Mohamed; Agadr, Aomar

2013-01-01

La pathomimie cutanée se définit comme une maladie factice, provoquée dans un etat de conscience claire par le patient lui-même, au niveau du revêtement cutanéo-muqueux et/ou des phanères. Rare chez l'enfant, il s'agit d'une manifestation psychopathologique potentiellement grave et souvent difficile à prendre en charge. Nous rapportons le cas d'une fillette de 10 ans présentant une pathomimie sous forme de lésions excoriées multiples du visage. PMID:23504605

Aerodynamics of Vortical Type Flows in Three Dimensions: Conference Proceedings Held at Rotterdam, Netherlands on 25-28 April 1983.

DTIC Science & Technology

1983-07-01

crEE impose une onde de choc situde dane is zone Evolutive CD oO elle peut occuper une position stable en raison de is divergence...ENTR.E UNE ONDE DE CHOC ET UNE STRUCTURE TOURBILLONNAIRE ENROU LEE par J.Delery et E.Horowitz 5 ON THE GENERATION AND SUBSEQUENT DEVELOPMENT OF SPIRAL...dont une dclotge. ont fitA analysdes plus finement au vdlocimktre loser. Pour un dclatement, is structure moyenne de l’dcoulement ,dr*dien inclut un

Localisation humérale d'une tumeur à cellules géantes récidivantes (à propos d'un cas)

PubMed Central

Nader, Youssef; Serghini, Issam; Koulali, Idrissi Khalid; Salahi, Hicham; Galwia, Farid

2015-01-01

Les auteurs rapportent un cas de localisation rare d'une tumeur à cellules géantes au niveau de la palette humérale du coude droit chez un militaire de 36 ans de sexe masculin, la radio standard montrait une image kystique ne soufflant pas la corticale. L'examen anatomo-pathologique a permis d’ établir le diagnostic et le traitement a fait appel: au début a une Exérèse chirurgicale totale et une greffe osseuse par un greffon iliaque de la totalité de la palette huméral qui s'est compliquée à 6 mois de recule d une récidive locale. PMID:25995809

The Dress: Transforming a web viral event into a scientific survey.

PubMed

Moccia, Marcello; Lavorgna, Luigi; Lanzillo, Roberta; Brescia Morra, Vincenzo; Tedeschi, Gioacchino; Bonavita, Simona

2016-05-01

The Dress picture recently has become a hot topic on the Internet, prompting a debate whether it was black and blue, or white and gold. To investigate The Dress color perception in both multiple sclerosis (MS) patients, characterized by frequent visual system impairment with ensuing color vision effects, and general population. We developed a questionnaire to record demographics, clinical features, and The Dress color perception, posted on general and MS-specific social networks. No statistically significant differences were observed in The Dress color perception between MS patients (n=103) and general population (n=441). Furthermore, white and gold color perception was positively associated with aging in the general population (p=0.04), whereas negatively associated with progressive course (p=0.03) and longer disease duration (p<0.001) in MS patients, independently from patients' age. The Dress black and blue or white and gold perception might be due to aging in the general population, whereas black and blue perception, despite of aging, might suggest a specific effect of the MS burden (i.e. disease duration and progression) on the visual structures specifically involved in the white and gold perception. Copyright © 2016 Elsevier B.V. All rights reserved.

Do bees like Van Gogh's Sunflowers?

NASA Astrophysics Data System (ADS)

Chittka, Lars; Walker, Julian

2006-06-01

Flower colours have evolved over 100 million years to address the colour vision of their bee pollinators. In a much more rapid process, cultural (and horticultural) evolution has produced images of flowers that stimulate aesthetic responses in human observers. The colour vision and analysis of visual patterns differ in several respects between humans and bees. Here, a behavioural ecologist and an installation artist present bumblebees with reproductions of paintings highly appreciated in Western society, such as Van Gogh's Sunflowers. We use this unconventional approach in the hope to raise awareness for between-species differences in visual perception, and to provoke thinking about the implications of biology in human aesthetics and the relationship between object representation and its biological connotations.

The steady-state visual evoked potential in vision research: A review

PubMed Central

Norcia, Anthony M.; Appelbaum, L. Gregory; Ales, Justin M.; Cottereau, Benoit R.; Rossion, Bruno

2015-01-01

Periodic visual stimulation and analysis of the resulting steady-state visual evoked potentials were first introduced over 80 years ago as a means to study visual sensation and perception. From the first single-channel recording of responses to modulated light to the present use of sophisticated digital displays composed of complex visual stimuli and high-density recording arrays, steady-state methods have been applied in a broad range of scientific and applied settings.The purpose of this article is to describe the fundamental stimulation paradigms for steady-state visual evoked potentials and to illustrate these principles through research findings across a range of applications in vision science. PMID:26024451

Subjective figures and texture perception.

PubMed

Zucker, S W; Cavanagh, P

1985-01-01

A texture discrimination task using the Ehrenstein illusion demonstrates that subjective brightness effects can play an essential role in early vision. The subjectively bright regions of the Ehrenstein can be organized either as discs or as stripes, depending on orientation. The accuracy of discrimination between variants of the Ehrenstein and control patterns was a direct function of the presence of the illusory brightness stripes, being high when they were present and low otherwise. It is argued that neither receptive field structure nor spatial-frequency content can adequately account for these results. We suggest that the subjective brightness illusions, rather than being a high-level, cognitive aspect of vision, are in fact the result of an early visual process.

The perception of geometrical structure from congruence

NASA Technical Reports Server (NTRS)

Lappin, Joseph S.; Wason, Thomas D.

1989-01-01

The principle function of vision is to measure the environment. As demonstrated by the coordination of motor actions with the positions and trajectories of moving objects in cluttered environments and by rapid recognition of solid objects in varying contexts from changing perspectives, vision provides real-time information about the geometrical structure and location of environmental objects and events. The geometric information provided by 2-D spatial displays is examined. It is proposed that the geometry of this information is best understood not within the traditional framework of perspective trigonometry, but in terms of the structure of qualitative relations defined by congruences among intrinsic geometric relations in images of surfaces. The basic concepts of this geometrical theory are outlined.

From spectral information to animal colour vision: experiments and concepts.

PubMed

Kelber, Almut; Osorio, Daniel

2010-06-07

Many animals use the spectral distribution of light to guide behaviour, but whether they have colour vision has been debated for over a century. Our strong subjective experience of colour and the fact that human vision is the paradigm for colour science inevitably raises the question of how we compare with other species. This article outlines four grades of 'colour vision' that can be related to the behavioural uses of spectral information, and perhaps to the underlying mechanisms. In the first, even without an (image-forming) eye, simple organisms can compare photoreceptor signals to locate a desired light environment. At the next grade, chromatic mechanisms along with spatial vision guide innate preferences for objects such as food or mates; this is sometimes described as wavelength-specific behaviour. Here, we compare the capabilities of di- and trichromatic vision, and ask why some animals have more than three spectral types of receptors. Behaviours guided by innate preferences are then distinguished from a grade that allows learning, in part because the ability to learn an arbitrary colour is evidence for a neural representation of colour. The fourth grade concerns colour appearance rather than colour difference: for instance, the distinction between hue and saturation, and colour categorization. These higher-level phenomena are essential to human colour perception but poorly known in animals, and we suggest how they can be studied. Finally, we observe that awareness of colour and colour qualia cannot be easily tested in animals.

Multisensory flavor perception.

PubMed

Spence, Charles

2015-03-26

The perception of flavor is perhaps the most multisensory of our everyday experiences. The latest research by psychologists and cognitive neuroscientists increasingly reveals the complex multisensory interactions that give rise to the flavor experiences we all know and love, demonstrating how they rely on the integration of cues from all of the human senses. This Perspective explores the contributions of distinct senses to our perception of food and the growing realization that the same rules of multisensory integration that have been thoroughly explored in interactions between audition, vision, and touch may also explain the combination of the (admittedly harder to study) flavor senses. Academic advances are now spilling out into the real world, with chefs and food industry increasingly taking the latest scientific findings on board in their food design. Copyright © 2015 Elsevier Inc. All rights reserved.

Visual coding of human bodies: perceptual aftereffects reveal norm-based, opponent coding of body identity.

PubMed

Rhodes, Gillian; Jeffery, Linda; Boeing, Alexandra; Calder, Andrew J

2013-04-01

Despite the discovery of body-selective neural areas in occipitotemporal cortex, little is known about how bodies are visually coded. We used perceptual adaptation to determine how body identity is coded. Brief exposure to a body (e.g., anti-Rose) biased perception toward an identity with opposite properties (Rose). Moreover, the size of this aftereffect increased with adaptor extremity, as predicted by norm-based, opponent coding of body identity. A size change between adapt and test bodies minimized the effects of low-level, retinotopic adaptation. These results demonstrate that body identity, like face identity, is opponent coded in higher-level vision. More generally, they show that a norm-based multidimensional framework, which is well established for face perception, may provide a powerful framework for understanding body perception.

Advancing STEM Education: A 2020 Vision

ERIC Educational Resources Information Center

Bybee, Rodger W.

2010-01-01

STEM (an acronym for science, technology, engineering and mathematics) had its origins in the 1990s at the National Science Foundation (NSF) and has been used as a generic label for any event, policy, program, or practice that involves one or several of the STEM disciplines. However, a recent survey on the "perception of STEM" found that most…

Establishing Systematic Modular Courses for Key Teaching Competencies of Teachers in Hsinchu City

ERIC Educational Resources Information Center

Cheng, Yuan-Chuan; Chen, Yin-Che; Chiang, Woei-Min; Yang, Chuan-Lien

2015-01-01

The evolution of the Internet, trends in mobile device usage, and changes in the perceptions of city leaders and residents have gradually transformed cities into smart cities. Through a literature review, survey analysis, and focus group interview, this study explored the educational vision and consensus in developing Smart Hsinchu, and analyzed…

Modelling Subjectivity in Visual Perception of Orientation for Image Retrieval.

ERIC Educational Resources Information Center

Sanchez, D.; Chamorro-Martinez, J.; Vila, M. A.

2003-01-01

Discussion of multimedia libraries and the need for storage, indexing, and retrieval techniques focuses on the combination of computer vision and data mining techniques to model high-level concepts for image retrieval based on perceptual features of the human visual system. Uses fuzzy set theory to measure users' assessments and to capture users'…

Shared Perception for Autonomous Systems

DTIC Science & Technology

2015-08-24

minivan or sport utility vehicle (SUV) may be around 1.8 meters tall. Next, a height distribution of ~ 1.5, 0.3 was used to project the car detections...Vision, vol. 60, no. 2, 2004, pp. 91–110. 4. N. Snavely, S.M. Seitz, and R. Szeliski, “Photo Tourism : Exploring Photo Collections in 3D,” Proceedings of

A Personal Vision Quest: Learning To Think Like an Artist.

ERIC Educational Resources Information Center

Dake, Dennis M.

Using the metaphoric story device of two tribes, one that builds their culture around words and the other which depends primarily on visual perception, this paper suggests a distinctive mental paradigm at work within the society of artists, who pursue visual literacy through graphic ideation. The author discusses his education in art and his…

Consumers' Perspectives on Effective Orientation and Mobility Services for Diabetic Adults Who Are Visually Impaired

ERIC Educational Resources Information Center

Griffin-Shirley, Nora; Kelley, Pat; Matlock, Dwayne; Page, Anita

2006-01-01

The authors interviewed and videotaped diabetic adults with visual impairments about their perceptions of orientation and mobility (O&M) services that they had received. The visual impairments of these middle-aged adults ranged from totally blind to low vision. The interview questions focused on demographic information about the interviewees, the…

A Phenomenology of Teacher and Parent Perceptions of the Characteristics of Effective Schools: Working toward a Shared Vision

ERIC Educational Resources Information Center

Sroufe, William David

2013-01-01

Research conducted at schools that have outperformed their counterparts points to specific characteristics that make them successful. These characteristics brought about the development of the effective schools correlates by Ronald Edmonds (1979). Various people from across the United States and in various occupations perceive these correlates…

Rewriting Identity: Social Meanings of Literacy and "Re-Visions" of Self.

ERIC Educational Resources Information Center

Mahiri, Jabari; Godley, Amanda J.

1998-01-01

Studies the life story and perceptions of literacy of a highly literate Latina female college student who developed Carpal Tunnel Syndrome. Finds that the woman's ability to write had been the foundation on which her social meanings of literacy rested: her life story revealed how her identity was influenced by societal values for writing and…

Politically Conservative Preservice Teachers and the Spiral of Silence: Implications for Teacher Education

ERIC Educational Resources Information Center

Journell, Wayne

2017-01-01

A common perception within politically conservative circles is that American colleges and universities are bastions of liberal thought led by left-leaning faculty who seek to indoctrinate their students into adopting progressive views of the world. The purpose of this study is not to debate or justify a progressive vision of teacher education.…

76 FR 40443 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

... traumatic injury that occurred in 1994. The best corrected visual acuity in his right eye is hand motion... his left eye due to a traumatic injury sustained in 1982. The visual acuity in his right eye is 20/20.... Newman Mr. Newman, 50, has no light perception in his left eye due to a traumatic injury that occurred...

Mucocèle appendiculaire: à propos d'un cas observé à Lubumbashi

PubMed Central

Wakunga, Eric; Mukuku, Olivier; Bugeme, Marcellin; Tshiband, Moïse; Kipili, Audifax; Mobambo, Pitchou; Arung, Willy; Wakunga, Warach

2014-01-01

La mucocèle appendiculaire est une entité pathologique rare, mais potentiellement dangereuse, elle se présente sous différentes formes cliniques. Nous rapportons ici un cas d'une patiente âgée de 49 ans sans antécédents chirurgicaux chez qui nous avons découvert d'une façon fortuite cette affection. La clinique était celle d'un syndrome appendiculaire aigu patent et elle révélait une masse dans la fosse iliaque droite. Les examens de laboratoire ont montré une hyperleucocytose et une vitesse de sédimentation augmentée. L’échographie a démontré une masse kystique péricaecal. La patiente a subi une appendicectomie avec cæcectomie partielle et la pièce opératoire appendiculaire mesurait 153 mm de longueur et 64 mm de diamètre. L'analyse anatomopathologique de celle-ci a confirmé le diagnostic de mucocèle appendiculaire sans cellules de malignité. Les suites opératoires ont été simples et la patiente est sortie au cinquième jour postopératoire. PMID:25368725

Multisensory Rehabilitation Training Improves Spatial Perception in Totally but Not Partially Visually Deprived Children

PubMed Central

Cappagli, Giulia; Finocchietti, Sara; Baud-Bovy, Gabriel; Cocchi, Elena; Gori, Monica

2017-01-01

Since it has been shown that spatial development can be delayed in blind children, focused sensorimotor trainings that associate auditory and motor information might be used to prevent the risk of spatial-related developmental delays or impairments from an early age. With this aim, we proposed a new technological device based on the implicit link between action and perception: ABBI (Audio Bracelet for Blind Interaction) is an audio bracelet that produces a sound when a movement occurs by allowing the substitution of the visuo-motor association with a new audio-motor association. In this study, we assessed the effects of an extensive but entertaining sensorimotor training with ABBI on the development of spatial hearing in a group of seven 3–5 years old children with congenital blindness (n = 2; light perception or no perception of light) or low vision (n = 5; visual acuity range 1.1–1.7 LogMAR). The training required the participants to play several spatial games individually and/or together with the psychomotor therapist 1 h per week for 3 months: the spatial games consisted of exercises meant to train their ability to associate visual and motor-related signals from their body, in order to foster the development of multisensory processes. We measured spatial performance by asking participants to indicate the position of one single fixed (static condition) or moving (dynamic condition) sound source on a vertical sensorized surface. We found that spatial performance of congenitally blind but not low vision children is improved after the training, indicating that early interventions with the use of science-driven devices based on multisensory capabilities can provide consistent advancements in therapeutic interventions, improving the quality of life of children with visual disability. PMID:29097987

Developmental visual perception deficits with no indications of prosopagnosia in a child with abnormal eye movements.

PubMed

Gilaie-Dotan, Sharon; Doron, Ravid

2017-06-01

Visual categories are associated with eccentricity biases in high-order visual cortex: Faces and reading with foveally-biased regions, while common objects and space with mid- and peripherally-biased regions. As face perception and reading are among the most challenging human visual skills, and are often regarded as the peak achievements of a distributed neural network supporting common objects perception, it is unclear why objects, which also rely on foveal vision to be processed, are associated with mid-peripheral rather than with a foveal bias. Here, we studied BN, a 9 y.o. boy who has normal basic-level vision, abnormal (limited) oculomotor pursuit and saccades, and shows developmental object and contour integration deficits but with no indication of prosopagnosia. Although we cannot infer causation from the data presented here, we suggest that normal pursuit and saccades could be critical for the development of contour integration and object perception. While faces and perhaps reading, when fixated upon, take up a small portion of central visual field and require only small eye movements to be properly processed, common objects typically prevail in mid-peripheral visual field and rely on longer-distance voluntary eye movements as saccades to be brought to fixation. While retinal information feeds into early visual cortex in an eccentricity orderly manner, we hypothesize that propagation of non-foveal information to mid and high-order visual cortex critically relies on circuitry involving eye movements. Limited or atypical eye movements, as in the case of BN, may hinder normal information flow to mid-eccentricity biased high-order visual cortex, adversely affecting its development and consequently inducing visual perceptual deficits predominantly for categories associated with these regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tumeur stromale du mésentère: une cause inhabituelle d'une masse abdominale

PubMed Central

Tarchouli, Mohamed; Bounaim, Ahmed; Boudhas, Adil; Ratbi, Moulay Brahim; Ndjota, Bobby Nguele; Ali, Abdelmounaim Ait; Sair, Khalid

2015-01-01

Les tumeurs stromales gastro-intestinales (GIST) sont les tumeurs mésenchymateuses les plus fréquentes du tractus digestif. Elles représentent une entité nosologique individualisée depuis la découverte de l'expression quasi-constante de la protéine c-Kit détectée par la coloration immunohistochimique de l'antigène CD117. Des tumeurs avec les mêmes caractéristiques morphologiques et immuno-phénotypiques peuvent rarement apparaître en dehors du tractus gastro-intestinal. Nous rapportons le cas d'une jeune patiente de 34 ans présentant une masse tumorale mésentérique se révélant être de nature stromale sans aucun contact avec la paroi intestinale. Il s'agit d'une localisation très rare des tumeurs stromales à laquelle il faut penser en préopératoire afin d'avoir une conduite thérapeutique adaptée et efficace. PMID:26327998

Realisation et Applications D'un Laser a Fibre a L'erbium Monofrequence

NASA Astrophysics Data System (ADS)

Larose, Robert

L'incorporation d'ions de terres rares a l'interieur de la matrice de verre d'une fibre optique a permis l'emergence de composants amplificateurs tout-fibre. Le but de cette these consiste d'une part a analyser et a modeliser un tel dispositif et d'autre part, a fabriquer puis a caracteriser un amplificateur et un oscillateur a fibre. A l'aide d'une fibre fortement dopee a l'erbium fabriquee sur demande, on realise un laser a fibre syntonisable qui fonctionne en regime multimodes longitudinaux avec une largeur de raie de 1.5 GHz et egalement comme source monofrequencielle de largeur de raie de 70 kHz. Le laser sert ensuite a caracteriser un reseau de Bragg ecrit par photosensibilite dans une fibre optique. La technique de syntonisation permet aussi l'asservissement au fond d'une resonance de l'acetylene. Le laser garde alors la position centrale de la raie avec une erreur de moins de 1 MHz corrigeant ainsi les derives mecaniques de la cavite.

Comparing sports vision among three groups of soft tennis adolescent athletes: Normal vision, refractive errors with and without correction

PubMed Central

Chang, Shih-Tsun; Liu, Yen-Hsiu; Lee, Jiahn-Shing; See, Lai-Chu

2015-01-01

Background: The effect of correcting static vision on sports vision is still not clear. Aim: To examine whether sports vision (depth perception [DP], dynamic visual acuity [DVA], eye movement [EM], peripheral vision [PV], and momentary vision [MV],) were different among soft tennis adolescent athletes with normal vision (Group A), with refractive error and corrected with (Group B) and without eyeglasses (Group C). Setting and Design: A cross-section study was conducted. Soft tennis athletes aged 10–13 who played softball tennis for 2–5 years, and who were without any ocular diseases and without visual training for the past 3 months were recruited. Materials and Methods: DPs were measured in an absolute deviation (mm) between a moving rod and fixing rod (approaching at 25 mm/s, receding at 25 mm/s, approaching at 50 mm/s, receding at 50 mm/s) using electric DP tester. A smaller deviation represented better DP. DVA, EM, PV, and MV were measured on a scale from 1 (worse) to 10 (best) using ATHLEVISION software. Statistical Analysis: Chi-square test and Kruskal–Wallis test was used to compare the data among the three study groups. Results: A total of 73 athletes (37 in Group A, 8 in Group B, 28 in Group C) were enrolled in this study. All four items of DP showed significant difference among the three study groups (P = 0.0051, 0.0004, 0.0095, 0.0021). PV displayed significant difference among the three study groups (P = 0.0044). There was no significant difference in DVA, EM, and MV among the three study groups. Conclusions: Significant better DP and PV were seen among soft tennis adolescent athletes with normal vision than those with refractive error regardless whether they had eyeglasses corrected. On the other hand, DVA, EM, and MV were similar among the three study groups. PMID:26632127

African Americans' perception of risk for diabetes complications.

PubMed

Calvin, Donna; Quinn, Lauretta; Dancy, Barbara; Park, Chang; Fleming, Shirley G; Smith, Eva; Fogelfeld, Leon

2011-01-01

The purpose of this exploratory, descriptive, correlational study was to describe the perceived risk for diabetes complications among urban African American adults (18-75 years old) with type 2 diabetes and to explore the interrelationships among illness perception, well-being, perceptions of risk for diabetes complications, and selected physiologic measures of diabetes risk: hemoglobin A1C, blood pressure, and microalbuminuria. Urban African American adults with type 2 diabetes (N = 143) were recruited from 3 Chicago city public health clinics. They completed a demographic survey and 3 instruments: the Risk Perception Survey-Diabetes Mellitus, the 12-item Well-being Questionnaire, and the Revised Illness Perception Questionnaire. Physiologic measures included blood pressure, urine for microalbuminuria, and capillary blood for A1C. There was low perception of risk for diabetes complications, which was incongruent with the physiologic measures of risk. Less than 33% of participants saw themselves as being at high risk for developing any complications of diabetes, with the exception of vision problems (39%), despite the fact that physiologic measures of risk for diabetes complications were high in this sample. Risk perception was associated with well-being, perception of negative consequences, number of symptoms, and negative emotions related to diabetes. Risk perception was not in line with risk, as indicated by physiologic measures; thus, it is necessary to heighten this population's perception of risk for diabetes complications.

Une complication exceptionnelle du tétanos généralisé: l’embolie pulmonaire

PubMed Central

Regaieg, Kais; Bahloul, Mabrouk; Gargouri, Rahma; Bouattour, Abir; Chelly, Hèdi; Bouaziz, Mounir

2016-01-01

Le tétanos est une maladie caractérisée par une paralysie spastique et des spasmes. C’est une pathologie grave. Elle nécessite une prise en charge en milieu de réanimation. La mortalité est essentiellement liée aux complications neurovégétatives et infectieuses. Les complications thromboemboliques sont exceptionnelles au cours de cette maladie. A notre connaissance, l’embolie pulmonaire n’a jamais été rapportée et confirmée au cours du tétanos généralisé. Nous présentons à travers cette observation un cas de tétanos généralisé compliqué d’une embolie pulmonaire fibrino cruorique. PMID:28292134

Cardiomyopathie du péripartum: à propos d’une observation et revue de la littérature

PubMed Central

Bouzerda, Abdelmajid

2016-01-01

La cardiomyopathie du péripartum ou cardiomyopathie gravidique primitive, est une entité rare et méconnue définie comme une insuffisance cardiaque systolique survenant le dernier mois de la grossesse ou les cinq premiers mois du postpartum en l'absence d'étiologie connue ou de cardiopathie préexistante. Nous rapportons l'observation d'une jeune patiente de 31 ans sans antécédents pathologiques particuliers admise pour une poussée d'insuffisance cardiaque gauche 1mois après son accouchement. Le contexte de péripartum nous a fait penser au diagnostic et a motivé la réalisation d'une Echocardiographie qui a confirmé cette entité. PMID:28154713

Epidémiologie et facteurs de risque des complications respiratoires majeures après chirurgie de l'aorte abdominale au CHU Ibn Sina, Maroc

PubMed Central

Awab, Almahdi; Elahmadi, Brahim; Lamkinsi, Tarik; El Moussaoui, Rachid; El Hijri, Ahmed; Azzouzi, Abderrahim; Alilou, Mustapha

2013-01-01

Introduction L'incidence des complications respiratoires postopératoires (CRPO) reste très diversement appréciées selon les critères diagnostiques retenues dans les différentes études, ce qui la fait varier de 5 à plus de 50%. Les CRPO majeurs après chirurgie de l'aorte abdominale sont responsables d'une grande morbi-mortalité pouvant aller jusqu’à 36%, d'une durée d'hospitalisation et d'un coût plus importants. Ainsi dans l'optique d'améliorer notre prise en charge périopératoire de la chirurgie de l'aorte, nous avons décidé de mener une étude pour dresser le profil épidémiologique et déterminer les facteurs de risque des complications respiratoires dans notre contexte Méthodes Il s'agit d'une étude de cohorte rétrospective du mois de Janvier 2007 au mois de décembre 2011 portant sur l'ensemble des patients opérés pour pathologie aortique au bloc opératoire central de l'hôpital Ibn Sina de Rabat, Maroc. Résultats Cent vingt cinq patients ont été inclus dans notre étude, 24 patients ont été opérés pour anévrysme de l'aorte abdominale et 101 patients pour lésion occlusive aortoiliaque. Dans notre série 22 malades soit 17,6% ont présenté une complication respiratoire majeure avec, une reventilation dans 4,8% des cas, une difficulté de sevrage de la ventilation artificielle dans 3,2% des cas, une pneumopathie dans 4% des cas, un syndrome de détresse respiratoire aigue (SDRA) dans 4% des cas et une nécessité de fibroaspiration bronchique dans 1,6% des cas. En analyse univariée: l’âge, la présence d'une BPCO avec dyspnée stade 3 ou 4, la présence d'une anomalie à l'EFR préopératoire, la présence d'un stade avancé (III ou IV) de LOAI et la reprise chirurgicale étaient statistiquement associés à la survenue d'une complication respiratoire postopératoire. En analyse multivariée, seule une anomalie à l'EFR en préopératoire constituait un facteur de risque indépendant de survenue d'une complication respiratoire postopératoire dans notre série avec un Odds Ratio (OR): 11,5; un Intervalle de Confiance (IC) à 95% de (1,6 - 85,2) et un p = 0,016. Conclusion Au terme de notre étude, il nous parait donc nécessaire pour diminuer l'incidence des CRPO majeurs dans notre population, d'agir sur les facteurs que nous jugeons modifiables tel l'amélioration de l’état respiratoire basal moyennant une préparation respiratoire préopératoire, s'intégrant dans un véritable programme de réhabilitation et associant une rééducation à l'effort, une kinésithérapie incitative ainsi qu'une optimisation des thérapeutiques habituelles. PMID:23504435

Etiologie Rare de Sinusites Nosocomiales en Milieu de Reanimation - A Propos d'une Observation

PubMed Central

Messadi, A.A.; Oueslati, S.; Thabet, L.; Bousselmi, K.; Menif, E.

2006-01-01

Summary Les sinusites nosocomiales ne sont pas rares en réanimation. Elles surviennent en général dans les suites d'une intubation nasotrachéale voire même orotrachéale. Le tubage gastrique peut être à lui seul à l'origine d'une sinusite nosocomiale. Nous rapportons le cas d'une patiente hospitalisée qui a été victime de brûlures étendues chez qui la sonde nasogastrique a été à l'origine d'une pansinusite dont l'issue a été fatale. PMID:21991055

Maladie de Horton révélée par une dyspnée

PubMed Central

Mahfoudhi, Madiha; Mamlouk, Habiba; Turki, Sami; Kheder, Adel

2015-01-01

Les manifestations pleuro-pulmonaires de la maladie de Horton sont rares et peu connues. Elles peuvent être inaugurales, à l'origine d'un retard à la prise en charge si elles sont méconnues. Il s'agissait d'un patient âgé de 75 ans, admis pour une dyspnée, une toux chronique et une fièvre. Il a reçu une antibiothérapie et a bénéficié d'une fibroscopie bronchique avec lavage broncho-alvéolaire à la recherche d'un germe, qui a révélé plutôt, une alvéolite lymphocytaire. L’évolution était marquée par la persistance des signes cliniques et du syndrome inflammatoire biologique. Un angio-scanner thoracique et une échographie cardiaque étaient sans anomalies. Une origine cardiaque, musculaire, hématologique, néoplasique, vasculaire ou métabolique de la dyspnée a été éliminée. Une maladie de Horton a été évoquée. La biopsie de l'artère temporale a confirmé le diagnostic d'une maladie de Horton. L’évolution sous corticothérapie était marquée par la disparition des signes cliniques et biologiques. Les manifestations pleuro-pulmonaires au cours de la maladie de Horton sont rares, et classiquement, rarement révélatrices de la maladie. La dyspnée peut initialement égarer le diagnostic vers d'autres étiologies notamment infectieuses. Le but de ce travail est d'insister sur le fait que la connaissance de ces différentes manifestations respiratoires au cours de la maladie de Horton (toux persistante, dyspnée, épanchement pleural) est utile au clinicien afin de prescrire une corticothérapie, chez un sujet le plus souvent âgé ayant un état fébrile et inflammatoire prolongé, permettant ainsi d’éviter l'apparition de complications. PMID:26161171

Visual Prostheses: The Enabling Technology to Give Sight to the Blind

PubMed Central

Maghami, Mohammad Hossein; Sodagar, Amir Masoud; Lashay, Alireza; Riazi-Esfahani, Hamid; Riazi-Esfahani, Mohammad

2014-01-01

Millions of patients are either slowly losing their vision or are already blind due to retinal degenerative diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) or because of accidents or injuries. Employment of artificial means to treat extreme vision impairment has come closer to reality during the past few decades. Currently, many research groups work towards effective solutions to restore a rudimentary sense of vision to the blind. Aside from the efforts being put on replacing damaged parts of the retina by engineered living tissues or microfabricated photoreceptor arrays, implantable electronic microsystems, referred to as visual prostheses, are also sought as promising solutions to restore vision. From a functional point of view, visual prostheses receive image information from the outside world and deliver them to the natural visual system, enabling the subject to receive a meaningful perception of the image. This paper provides an overview of technical design aspects and clinical test results of visual prostheses, highlights past and recent progress in realizing chronic high-resolution visual implants as well as some technical challenges confronted when trying to enhance the functional quality of such devices. PMID:25709777

[Surgical treatment of advanced retinopathy of prematurity--last chance for vision. Report 2. Analysis of functional results].

PubMed

Baranov, A V; Troianovskiĭ, R L

2012-01-01

Functional results of staged surgical treatment of advanced retinopathy of prematurity (ROP) are analyzed between 2005 and 2010 in ophthalmologic department of city children's hospital ( St. Petersburg). A total of 154 children (303 eyes) were operated. The assessment of visual functions was performed using proposed original method. Subject vision was achieved in 65% of 20 eyes (6,6%) with 4B stage ROP. Fair anatomic results were achieved in 131 eyes of children with 5 stage ROP (283 eyes), light perception was preserved in 52 eyes (39,7%), capability to distinguish large objects appeared in 40 eyes (30,5%) and subject vision developed in 39 eyes (29,8%). Correlation between visual functions and environmental conditions was found, in particular presence or absence of long-term period of training in color and individual objects distinguishing. In a group of children training resulted in achievement of fair functions (subject vision, capability to distinguish large objects) in 81,2% of patients, where as in a group without training the same capabilities developed in 31,8% of cases only. Functional outcomes were also found to depend on CNS condition and time of surgery.

Optoelectronic stereoscopic device for diagnostics, treatment, and developing of binocular vision

NASA Astrophysics Data System (ADS)

Pautova, Larisa; Elkhov, Victor A.; Ovechkis, Yuri N.

2003-08-01

Operation of the device is based on alternative generation of pictures for left and right eyes on the monitor screen. Controller gives pulses on LCG so that shutter for left or right eye opens synchronously with pictures. The device provides frequency of switching more than 100 Hz, and that is why the flickering is absent. Thus, a separate demonstration of images to the left eye or to the right one in turn is obtained for patients being unaware and creates the conditions of binocular perception clsoe to natural ones without any additional separation of vision fields. LC-cell transfer characteristic coodination with time parameters of monitor screen has enabled to improve stereo image quality. Complicated problem of computer stereo images with LC-glasses is so called 'ghosts' - noise images that come to blocked eye. We reduced its influence by adapting stereo images to phosphor and LC-cells characteristics. The device is intended for diagnostics and treatment of stabismus, amblyopia and other binocular and stereoscopic vision impairments, for cultivating, training and developing of stereoscopic vision, for measurements of horizontal and vertical phoria, phusion reserves, the stereovision acuity and some else, for fixing central scotoma borders, as well as suppression scotoma in strabismus too.

Étude des déterminants individuels de l’adoption du dossier de santé électronique du Québec

PubMed Central

Mezni, H; M-P, Gagnon; Duplantie, J

2016-01-01

Résumé Objectif Selon des études précédentes, les dossiers de santé électroniques peuvent améliorer l’efficacité, la sécurité et la qualité de la prise en charge médicale. Cependant, les prestataires de soins restent réticents quant à son utilisation, ce qui limite son impact sur le système de santé. La présente étude avait pour objectif d’évaluer les perceptions des médecins face au dossier de santé du Québec. Méthodes À partir d’une revue de la littérature sur les facteurs influençant l’adoption des nouvelles technologies de l’information et des communications (NTIC) en général et de la cybersanté en particulier, nous avons élaboré un questionnaire semi-structuré. Au total, 12 médecins utilisateurs potentiels du dossier de santé du Québec (DSQ) ont complété et retourné le questionnaire. Par la suite, nous avons opéré une analyse thématique de contenu, suivie par une théorisation des concepts obtenus. Résultats L’intention d’adopter le DSQ est influencée positivement par l’utilité perçue, la facilité d’utilisation perçue, la démonstrabilité des résultats, la compatibilité du système avec la pratique et l’autoefficacité informatique perçue par les médecins. Inversement, la résistance au changement influence négativement l’adoption du DSQ par les médecins. Conclusion L’identification des déterminants de l’adoption du dossier de santé du Québec est cruciale pour les responsables du secteur de la santé au Québec. Il sera ainsi possible de saisir les attentes des utilisateurs potentiels et d’ajuster les stratégies d’implantation en vue de favoriser une meilleure intégration de cette technologie dans les pratiques médicales. PMID:27867453

Thrombasthénie de Glanzmann: à propos de 11 cas

PubMed Central

Mukendi, Jean-Louis Ntumba; Benkirane, Souad; Masrar, Azlarab

2015-01-01

Introduction La thrombasthénie de Glanzmann est une pathologie hémorragique héréditaire rare due à une déficience ou un dysfonctionnement du complexe glycoprotéique IIb/IIIa de la membrane plaquettaire. Le but de notre étude est de décrire les caractéristiques démographiques, cliniques et biologiques d'une série de patients atteints de thrombasthénie de Glanzmann. Méthodes C'est une étude portant sur tous les patients atteints de thrombasthénie de Glanzmann diagnostiqués au Laboratoire Central d'Hématologie du Centre Hospitalier Ibn Sina de Rabat au Maroc pendant la période allant du 1er mars 2011 au 31 mars 2013, soit 25 mois. Après avoir recueilli les données épidémiologiques et cliniques de nos patients, nous avons réalisé une étude biologique comportant une numération plaquettaire et une agrégométrie. Résultats 11 patients ont présenté des profils agrégométriques compatibles à une TG. La majorité de ces malades étaient issus de mariages consanguins (54,5%) et originaires de régions situées dans le nord du Maroc. Le syndrome hémorragique s'est révélé principalement cutanéo-muqueux, avec une prédominance des gingivorragies (72,7%), des épistaxis (63,6%) et des ecchymoses (45,5%). Conclusion Nos résultats ont montré que la thrombasthénie de Glanzmann est une pathologie relativement fréquente au Maroc. PMID:26587119