WorldWideScience

Sample records for eye field fef

  1. Functional organization of the left inferior precentral sulcus: dissociating the inferior frontal eye field and the inferior frontal junction

    NARCIS (Netherlands)

    Derrfuss, J.; Vogt, V.L.; Fiebach, C.J.; Cramon, D.Y. von; Tittgemeyer, M.

    2012-01-01

    Two eye fields have been described in the human lateral frontal cortex: the frontal eye field (FEF) and the inferior frontal eye field (iFEF). The FEF has been extensively studied and has been found to lie at the ventral part of the superior precentral sulcus. Much less research, however, has focuse

  2. TMS pulses on the frontal eye fields break coupling between visuospatial attention and eye movements

    NARCIS (Netherlands)

    Neggers, S.F.W.; Huijbers, W.; Vrijlandt, C.M.; Vlaskamp, B.N.S.; Schutter, D.J.L.G.; Kenemans, J.L.

    2007-01-01

    While preparing a saccadic eye movement, visual processing of the saccade goal is prioritized. Here, we provide evidence that the frontal eye fields (FEFs) are responsible for this coupling between eye movements and shifts of visuospatial attention. Functional magnetic resonance imaging ( fMRI)-guid

  3. FEF inactivation with improved optogenetic methods.

    Science.gov (United States)

    Acker, Leah; Pino, Erica N; Boyden, Edward S; Desimone, Robert

    2016-11-15

    Optogenetic methods have been highly effective for suppressing neural activity and modulating behavior in rodents, but effects have been much smaller in primates, which have much larger brains. Here, we present a suite of technologies to use optogenetics effectively in primates and apply these tools to a classic question in oculomotor control. First, we measured light absorption and heat propagation in vivo, optimized the conditions for using the red-light-shifted halorhodopsin Jaws in primates, and developed a large-volume illuminator to maximize light delivery with minimal heating and tissue displacement. Together, these advances allowed for nearly universal neuronal inactivation across more than 10 mm(3) of the cortex. Using these tools, we demonstrated large behavioral changes (i.e., up to several fold increases in error rate) with relatively low light power densities (≤100 mW/mm(2)) in the frontal eye field (FEF). Pharmacological inactivation studies have shown that the FEF is critical for executing saccades to remembered locations. FEF neurons increase their firing rate during the three epochs of the memory-guided saccade task: visual stimulus presentation, the delay interval, and motor preparation. It is unclear from earlier work, however, whether FEF activity during each epoch is necessary for memory-guided saccade execution. By harnessing the temporal specificity of optogenetics, we found that FEF contributes to memory-guided eye movements during every epoch of the memory-guided saccade task (the visual, delay, and motor periods).

  4. Measurements of simultaneously recorded spike and local field potentials suggest that spatial selection emerges in the frontal eye field

    OpenAIRE

    Monosov, Ilya E.; Trageser, Jason C.; Thompson, Kirk G.

    2008-01-01

    The frontal eye field (FEF) participates in selecting the location of behaviorally relevant stimuli for guiding attention and eye movements. We simultaneously recorded local field potentials (LFPs) and spiking activity in the FEF of monkeys performing memory-guided saccade and covert visual search tasks. We compared visual latencies and the time course of spatially selective responses in LFPs and spiking activity. Consistent with the view that LFPs represent synaptic input, visual responses a...

  5. ZERO-FIELD NUCLEAR MAGNETIC RESONANCE FOR STUDY OF ANTIFERROMAGNETIC PROPERTIES OF FeF3 MATERIALS

    Directory of Open Access Journals (Sweden)

    G. R. F. Suwandi

    2016-01-01

    Full Text Available Nuclear Magnetic Resonance (NMR has been used as a research tool in many fields. In this study, the magnetic properties, especially anti-ferromagnetic properties of FeF3 materials were investigated. Zero-field custom-built NMR method was used to investigate the anti-ferromagnetic properties in the materials. Experiments have been carried out by varying the sample temperatures from 8 K to 220 K. Ordinary spin echo pulse sequence 90⁰RF–τ–180⁰RF were used. Using Fast Fourier Transform, the signals in NMR spectrum were analyzed and the peak showed the resonance frequency. The result showed that resonance frequencies decrease with increasing in temperature. The frequency of the spectrum was around 85.41 MHz in the zero-temperature limit, and this corresponds with Fe hyperfine field at zero-temperature limit was 2.14 T. The temperature dependence of the local magnetization does not fit T2 Bloch’s Law very well. Instead, it fits the exponential form having an energy gap in the dispersion relation of the spin wave. It is obtained from the result that FeF3 is antiferromagnetic materials with energy gap of 11.466 meV and anisotropy energy of 1.045 meV.Nuclear Magnetic Resonance (NMR telah banyak digunakan sebagai “research tool” pada berbagai bidang kajian di fisika. Pada studi ini, akan dilakukan eksperimen untuk menguji sifat magnetik, khususnya antiferromagnetik pada material FeF3. Telah dilakukan eksperimen dengan memvariasikan temperatur pada sampel dari 8 K hingga 220 K. Pulse sequence yang digunakan adalah 90⁰RF–τ–180⁰RF. Dengan memanfaatkan Fast Fourier Transform, sinyal echo ini dapat dianalisis dalam bentuk spektrum NMR dengan puncak spektrum menunjukkan frekuensi resonansinya. Diperoleh bahwa frekuensi resonansi akan menurun seiring dengan kenaikan temperatur. Posisi frekuensi pada temperatur 0 K adalah sebesar 85,41 MHz, hal ini memperlihatkan bahwa medan hyperfine dari Fe sebesar 2,14 T pada temperatur 0 K. Kurva

  6. Disrupting frontal eye-field activity impairs memory recall.

    Science.gov (United States)

    Wantz, Andrea L; Martarelli, Corinna S; Cazzoli, Dario; Kalla, Roger; Müri, René; Mast, Fred W

    2016-04-13

    A large body of research demonstrated that participants preferably look back to the encoding location when retrieving visual information from memory. However, the role of this 'looking back to nothing' is still debated. The goal of the present study was to extend this line of research by examining whether an important area in the cortical representation of the oculomotor system, the frontal eye field (FEF), is involved in memory retrieval. To interfere with the activity of the FEF, we used inhibitory continuous theta burst stimulation (cTBS). Before stimulation was applied, participants encoded a complex scene and performed a short-term (immediately after encoding) or long-term (after 24 h) recall task, just after cTBS over the right FEF or sham stimulation. cTBS did not affect overall performance, but stimulation and statement type (object vs. location) interacted. cTBS over the right FEF tended to impair object recall sensitivity, whereas there was no effect on location recall sensitivity. These findings suggest that the FEF is involved in retrieving object information from scene memory, supporting the hypothesis that the oculomotor system contributes to memory recall.

  7. Incomplete suppression of distractor-related activity in the frontal eye field results in curved saccades.

    Science.gov (United States)

    McPeek, Robert M

    2006-11-01

    Saccades in the presence of distractors show significant trajectory curvature. Based on previous work in the superior colliculus (SC), we speculated that curvature arises when a movement is initiated before competition between the target and distractor goals has been fully resolved. To test this hypothesis, we recorded frontal eye field (FEF) activity for curved and straight saccades in search. In contrast to the SC, activity in FEF is normally poorly correlated with saccade dynamics. However, the FEF, like the SC, is involved in target selection. Thus if curvature is caused by incomplete target selection, we expect to see its neural correlates in the FEF. We found that saccades that curve toward a distractor are accompanied by an increase in perisaccadic activity of FEF neurons coding the distractor location, and saccades that curve away are accompanied by a decrease in activity. In contrast, for FEF neurons coding the target location, there is no significant difference in activity between curved and straight saccades. To establish that the distractor-related activity is causally related to saccade curvature, we applied microstimulation to sites in the FEF before saccades to targets presented without distractors. The stimulation was subthreshold for evoking saccades and the temporal structure of the stimulation train resembled the activity recorded for curved saccades. The resulting movements curved toward the location coded by the stimulation site. These results support the idea that saccade curvature results from incomplete suppression of distractor-related activity during target selection.

  8. Dynamics of visual receptive fields in the macaque frontal eye field.

    Science.gov (United States)

    Mayo, J Patrick; DiTomasso, Amie R; Sommer, Marc A; Smith, Matthew A

    2015-12-01

    Neuronal receptive fields (RFs) provide the foundation for understanding systems-level sensory processing. In early visual areas, investigators have mapped RFs in detail using stochastic stimuli and sophisticated analytical approaches. Much less is known about RFs in prefrontal cortex. Visual stimuli used for mapping RFs in prefrontal cortex tend to cover a small range of spatial and temporal parameters, making it difficult to understand their role in visual processing. To address these shortcomings, we implemented a generalized linear model to measure the RFs of neurons in the macaque frontal eye field (FEF) in response to sparse, full-field stimuli. Our high-resolution, probabilistic approach tracked the evolution of RFs during passive fixation, and we validated our results against conventional measures. We found that FEF neurons exhibited a surprising level of sensitivity to stimuli presented as briefly as 10 ms or to multiple dots presented simultaneously, suggesting that FEF visual responses are more precise than previously appreciated. FEF RF spatial structures were largely maintained over time and between stimulus conditions. Our results demonstrate that the application of probabilistic RF mapping to FEF and similar association areas is an important tool for clarifying the neuronal mechanisms of cognition.

  9. Functional organization of the left inferior precentral sulcus: dissociating the inferior frontal eye field and the inferior frontal junction.

    Science.gov (United States)

    Derrfuss, J; Vogt, V L; Fiebach, C J; von Cramon, D Y; Tittgemeyer, M

    2012-02-15

    Two eye fields have been described in the human lateral frontal cortex: the frontal eye field (FEF) and the inferior frontal eye field (iFEF). The FEF has been extensively studied and has been found to lie at the ventral part of the superior precentral sulcus. Much less research, however, has focused on the iFEF. Recently, it was suggested that the iFEF is located at the dorsal part of the inferior precentral sulcus. A similar location was proposed for the inferior frontal junction area (IFJ), an area thought to be involved in cognitive control processes. The present study used fMRI to clarify the topographical and functional relationship of the iFEF and the IFJ in the left hemispheres of individual participants. The results show that both the iFEF and the IFJ are indeed located at the dorsal part of the inferior precentral sulcus. Nevertheless, the activations were spatially dissociable in every individual examined. The IFJ was located more towards the depth of the inferior precentral sulcus, close to the junction with the inferior frontal sulcus, whereas the iFEF assumed a more lateral, posterior and superior position. Furthermore, the results provided evidence for a functional double dissociation: the iFEF was activated only in a comparison of saccades vs. button presses, but not in a comparison of incongruent vs. congruent Stroop conditions, while the opposite pattern was found at the IFJ. These results provide evidence for a spatial and functional dissociation of two directly adjacent areas in the left posterior frontal lobe.

  10. The frontal eye fields limit the capacity of visual short-term memory in rhesus monkeys.

    Science.gov (United States)

    Lee, Kyoung-Min; Ahn, Kyung-Ha

    2013-01-01

    The frontal eye fields (FEF) in rhesus monkeys have been implicated in visual short-term memory (VSTM) as well as control of visual attention. Here we examined the importance of the area in the VSTM capacity and the relationship between VSTM and attention, using the chemical inactivation technique and multi-target saccade tasks with or without the need of target-location memory. During FEF inactivation, serial saccades to targets defined by color contrast were unaffected, but saccades relying on short-term memory were impaired when the target count was at the capacity limit of VSTM. The memory impairment was specific to the FEF-coded retinotopic locations, and subject to competition among targets distributed across visual fields. These results together suggest that the FEF plays a crucial role during the entry of information into VSTM, by enabling attention deployment on targets to be remembered. In this view, the memory capacity results from the limited availability of attentional resources provided by FEF: The FEF can concurrently maintain only a limited number of activations to register the targets into memory. When lesions render part of the area unavailable for activation, the number would decrease, further reducing the capacity of VSTM.

  11. Distinct control of initiation and metrics of memory-guided saccades and vergence by the FEF: a TMS study.

    Directory of Open Access Journals (Sweden)

    Qing Yang

    Full Text Available BACKGROUND: The initiation of memory guided saccades is known to be controlled by the frontal eye field (FEF. Recent physiological studies showed the existence of an area close to FEF that controls also vergence initiation and execution. This study is to explore the effect of transcranial magnetic simulation (TMS over FEF on the control of memory-guided saccade-vergence eye movements. METHODOLOGY/PRINCIPAL FINDINGS: Subjects had to make an eye movement in dark towards a target flashed 1 sec earlier (memory delay; the location of the target relative to fixation point was such as to require either a vergence along the median plane, or a saccade, or a saccade with vergence; trials were interleaved. Single pulse TMS was applied on the left or right FEF; it was delivered at 100 ms after the end of memory delay, i.e. extinction of fixation LED that was the "go" signal. Twelve healthy subjects participated in the study. TMS of left or right FEF prolonged the latency of all types of eye movements; the increase varied from 21 to 56 ms and was particularly strong for the divergence movements. This indicates that FEF is involved in the initiation of all types of memory guided movement in the 3D space. TMS of the FEF also altered the accuracy but only for leftward saccades combined with either convergence or divergence; intrasaccadic vergence also increased after TMS of the FEF. CONCLUSIONS/SIGNIFICANCE: The results suggest anisotropy in the quality of space memory and are discussed in the context of other known perceptual motor anisotropies.

  12. A hierarchy of timescales explains distinct effects of local inhibition of primary visual cortex and frontal eye fields.

    Science.gov (United States)

    Cocchi, Luca; Sale, Martin V; L Gollo, Leonardo; Bell, Peter T; Nguyen, Vinh T; Zalesky, Andrew; Breakspear, Michael; Mattingley, Jason B

    2016-09-06

    Within the primate visual system, areas at lower levels of the cortical hierarchy process basic visual features, whereas those at higher levels, such as the frontal eye fields (FEF), are thought to modulate sensory processes via feedback connections. Despite these functional exchanges during perception, there is little shared activity between early and late visual regions at rest. How interactions emerge between regions encompassing distinct levels of the visual hierarchy remains unknown. Here we combined neuroimaging, non-invasive cortical stimulation and computational modelling to characterize changes in functional interactions across widespread neural networks before and after local inhibition of primary visual cortex or FEF. We found that stimulation of early visual cortex selectively increased feedforward interactions with FEF and extrastriate visual areas, whereas identical stimulation of the FEF decreased feedback interactions with early visual areas. Computational modelling suggests that these opposing effects reflect a fast-slow timescale hierarchy from sensory to association areas.

  13. Freezing field dependence of the exchange bias in uniaxial FeF sub 2 -CoPt heterosystems with perpendicular anisotropy

    CERN Document Server

    Kagerer, B; Kleemann, W

    2000-01-01

    The exchange bias effect is measured for the first time in FeF sub 2 -CoPt heterosystems with perpendicular anisotropy. The exchange field exhibits a strong dependence on the axial freezing field. This behavior is explained in terms of the microscopic spin structure at the interface, which is established on cooling to below T sub N. We calculate the dependence of the spin structure on the freezing field within the framework of an Ising model. It takes into account the Zeeman energy as well as an antiferromagnetic exchange coupling between the adjacent layers at the interface.

  14. Persistent spatial information in the frontal eye field during object-based short-term memory.

    Science.gov (United States)

    Clark, Kelsey L; Noudoost, Behrad; Moore, Tirin

    2012-08-08

    Spatial attention is known to gate entry into visual short-term memory, and some evidence suggests that spatial signals may also play a role in binding features or protecting object representations during memory maintenance. To examine the persistence of spatial signals during object short-term memory, the activity of neurons in the frontal eye field (FEF) of macaque monkeys was recorded during an object-based delayed match-to-sample task. In this task, monkeys were trained to remember an object image over a brief delay, regardless of the locations of the sample or target presentation. FEF neurons exhibited visual, delay, and target period activity, including selectivity for sample location and target location. Delay period activity represented the sample location throughout the delay, despite the irrelevance of spatial information for successful task completion. Furthermore, neurons continued to encode sample position in a variant of the task in which the matching stimulus never appeared in their response field, confirming that FEF maintains sample location independent of subsequent behavioral relevance. FEF neurons also exhibited target-position-dependent anticipatory activity immediately before target onset, suggesting that monkeys predicted target position within blocks. These results show that FEF neurons maintain spatial information during short-term memory, even when that information is irrelevant for task performance.

  15. Dissecting patterns of preparatory activity in the frontal eye fields during pursuit target selection.

    Science.gov (United States)

    Raghavan, Ramanujan T; Joshua, Mati

    2017-07-19

    We investigated the composition of preparatory activity of frontal eye field (FEF) neurons in monkeys performing a pursuit target selection task. In response to the orthogonal motion of a large and a small reward target, monkeys initiated pursuit biased towards the direction of large reward target motion. FEF neurons exhibited robust preparatory activity preceding movement initiation in this task. Preparatory activity consisted of two components, ramping activity that was constant across target selection conditions and a flat offset in firing rates that signaled the target selection condition. Ramping activity accounted for 50% of the variance in the preparatory activity and was linked most strongly, on a trial-by-trial basis, to pursuit eye movement latency rather than to its direction or gain. The offset in firing rates that discriminated target selection conditions accounted for 25% of the variance in the preparatory activity, and was commensurate with a winner-take-all representation signaling the direction of large reward target motion rather than a representation that matched the parameters of the upcoming movement. These offer new insights into the role the frontal eye fields play in target selection and pursuit control. They show that preparatory activity in the FEF signals more strongly when to move rather than where or how to move, and suggest that structures outside the FEF augment its contributions to the target selection process. Copyright © 2017, Journal of Neurophysiology.

  16. A probabilistic approach to receptive field mapping in the frontal eye fields

    Directory of Open Access Journals (Sweden)

    J. Patrick eMayo

    2016-03-01

    Full Text Available Studies of the neuronal mechanisms of perisaccadic vision often lack the resolution needed to determine important changes in receptive field (RF structure. Such limited analytical power can lead to inaccurate descriptions of visuomotor processing. To address this issue, we developed a precise, probabilistic technique that uses a generalized linear model (GLM for mapping the visual receptive fields of frontal eye field (FEF neurons during stable fixation (Mayo et al., 2015. We previously found that full-field RF maps could be obtained using 1-8 dot stimuli presented at frame rates of 10-150 ms. FEF responses were generally robust to changes in the number of stimuli presented or the rate of presentation, which allowed us to visualize RFs over a range of spatial and temporal resolutions. Here, we compare the quality of RFs obtained over different stimulus and GLM parameters to facilitate future work on the detailed mapping of FEF RFs. We first evaluate the interactions between the number of stimuli presented per trial, the total number of trials, and the quality of RF mapping. Next, we vary the spatial resolution of our approach to illustrate the tradeoff between visualizing RF sub-structure and sampling at high resolutions. We then evaluate local smoothing as a possible correction for situations where under-sampling occurs. Finally, we provide a preliminary demonstration of the usefulness of a probabilistic approach for visualizing full-field perisaccadic RF shifts. Our results present a powerful, and perhaps necessary, framework for studying perisaccadic vision is applicable to FEF and possibly other visuomotor regions of the brain.

  17. Division of labor in frontal eye field neurons during presaccadic remapping of visual receptive fields.

    Science.gov (United States)

    Shin, Sooyoon; Sommer, Marc A

    2012-10-01

    Our percept of visual stability across saccadic eye movements may be mediated by presaccadic remapping. Just before a saccade, neurons that remap become visually responsive at a future field (FF), which anticipates the saccade vector. Hence, the neurons use corollary discharge of saccades. Many of the neurons also decrease their response at the receptive field (RF). Presaccadic remapping occurs in several brain areas including the frontal eye field (FEF), which receives corollary discharge of saccades in its layer IV from a collicular-thalamic pathway. We studied, at two levels, the microcircuitry of remapping in the FEF. At the laminar level, we compared remapping between layers IV and V. At the cellular level, we compared remapping between different neuron types of layer IV. In the FEF in four monkeys (Macaca mulatta), we identified 27 layer IV neurons with orthodromic stimulation and 57 layer V neurons with antidromic stimulation from the superior colliculus. With the use of established criteria, we classified the layer IV neurons as putative excitatory (n = 11), putative inhibitory (n = 12), or ambiguous (n = 4). We found that just before a saccade, putative excitatory neurons increased their visual response at the RF, putative inhibitory neurons showed no change, and ambiguous neurons increased their visual response at the FF. None of the neurons showed presaccadic visual changes at both RF and FF. In contrast, neurons in layer V showed full remapping (at both the RF and FF). Our data suggest that elemental signals for remapping are distributed across neuron types in early cortical processing and combined in later stages of cortical microcircuitry.

  18. Frontal Eye Field, Where Art Thou? Anatomy, function and non-invasive manipulation of frontal regions involved in eye movements and associated cognitive operations

    Directory of Open Access Journals (Sweden)

    Marine eVernet

    2014-08-01

    Full Text Available The planning, control and execution of eye movements in 3D space relies on a distributed system of cortical and subcortical brain regions. Within this network, the Eye Fields have been described in animals as cortical regions in which electrical stimulation is able to trigger eye movements and influence their latency or accuracy. This review will focus on the Frontal Eye Field (FEF a hub region located in Humans in the vicinity of the pre-central sulcus and the dorsal-most portion of the superior frontal sulcus. The straightforward localization of the FEF through electrical stimulation in animals is difficult to translate to the healthy human brain, particularly with non-invasive neuroimaging techniques. Hence, in the first part of this review, we will describe attempts made to characterize the anatomical localization of this area in the human brain. The outcome of functional Magnetic Resonance Imaging (fMRI, Magneto-encephalography (MEG and particularly, non-invasive mapping methods such a Transcranial Magnetic Stimulation (TMS will be described and the variability of FEF localization across individuals and mapping techniques will be discussed. In the second part of this review, we will address the role of the FEF. We will explore its involvement both in the physiology of fixation, saccade, pursuit and vergence movements and in associated cognitive processes such as attentional orienting, visual awareness and perceptual modulation. Finally in the third part, we will review recent evidence suggesting the high level of malleability and plasticity of these regions and associated networks to non-invasive stimulation. The exploratory, diagnostic and therapeutic interest of such interventions for the modulation and improvement of perception in 3D space will be discussed.

  19. Attention Induced Gain Stabilization in Broad and Narrow-Spiking Cells in the Frontal Eye-Field of Macaque Monkeys.

    Science.gov (United States)

    Thiele, Alexander; Brandt, Christian; Dasilva, Miguel; Gotthardt, Sascha; Chicharro, Daniel; Panzeri, Stefano; Distler, Claudia

    2016-07-20

    Top-down attention increases coding abilities by altering firing rates and rate variability. In the frontal eye field (FEF), a key area enabling top-down attention, attention induced firing rate changes are profound, but its effect on different cell types is unknown. Moreover, FEF is the only cortical area investigated in which attention does not affect rate variability, as assessed by the Fano factor, suggesting that task engagement affects cortical state nonuniformly. We show that putative interneurons in FEF of Macaca mulatta show stronger attentional rate modulation than putative pyramidal cells. Partitioning rate variability reveals that both cell types reduce rate variability with attention, but more strongly so in narrow-spiking cells. The effects are captured by a model in which attention stabilizes neuronal excitability, thereby reducing the expansive nonlinearity that links firing rate and variance. These results show that the effect of attention on different cell classes and different coding properties are consistent across the cortical hierarchy, acting through increased and stabilized neuronal excitability. Cortical processing is critically modulated by attention. A key feature of this influence is a modulation of "cortical state," resulting in increased neuronal excitability and resilience of the network against perturbations, lower rate variability, and an increased signal-to-noise ratio. In the frontal eye field (FEF), an area assumed to control spatial attention in human and nonhuman primates, firing rate changes with attention occur, but rate variability, quantified by the Fano factor, appears to be unaffected by attention. Using recently developed analysis tools and models to quantify attention effects on narrow- and broad-spiking cell activity, we show that attention alters cortical state strongly in the FEF, demonstrating that its effect on the neuronal network is consistent across the cortical hierarchy. Copyright © 2016 Thiele et al.

  20. Frontal eye fields involved in shifting frame of reference within working memory for scenes

    DEFF Research Database (Denmark)

    Wallentin, Mikkel; Roepstorff, Andreas; Burgess, Neil

    2008-01-01

    Working memory (WM) evoked by linguistic cues for allocentric spatial and egocentric spatial aspects of a visual scene was investigated by correlating fMRI BOLD signal (or "activation") with performance on a spatial-relations task. Subjects indicated the relative positions of a person or object...... response during recall involving allocentric compared to egocentric spatial reference frames, and that this difference was larger in good performers than in poor performers as measured by the first behavioural principal component. The frontal eye fields may be used when subjects move their internal gaze...... during shifting reference frames in representational space. Analysis of actual eye movements in 3 subjects revealed no difference between egocentric and allocentric recall tasks where visual stimuli were also absent. Thus, the FEF machinery for directing eye movements may also be involved in changing...

  1. Evidence for a functional subdivision of Premotor Ear-Eye Field (Area 8B.

    Directory of Open Access Journals (Sweden)

    Marco eLanzilotto

    2015-01-01

    Full Text Available The Supplementary Eye Field (SEF and the Frontal Eye Field (FEF have been described as participating in gaze shift control. Recent evidence suggests, however, that other areas of the dorsomedial prefrontal cortex also influence gaze shift. Herein, we have investigated electrically evoked ear- and eye movements from the Premotor Ear-Eye Field, or PEEF (area 8B of macaque monkeys. We stimulated PEEF during spontaneous condition (outside the task performance and during the execution of a visual fixation task (VFT. In the first case, we functionally identified two regions within the PEEF: a core and a belt. In the core region, stimulation elicited forward ear movements; regarding the evoked eye movements, in some penetrations, stimulation elicited contraversive fixed-vectors with a mean amplitude of 5.14°; while in other penetrations, we observed prevalently contralateral goal-directed eye movements having end-points that fell within 15° in respect to the primary eye position. On the contrary, in the belt region, stimulation elicited backward ear movements; regarding the eye movements, in some penetrations stimulation elicited prevalently contralateral goal-directed eye movements having end-points that fell within 15° in respect to the primary eye position, while in the lateral edge of the investigated region, stimulation elicited contralateral goal-directed eye movements having end-points that fell beyond 15° in respect to the primary eye position. Stimulation during VFT either did not elicit eye movements or evoked saccades of only a few degrees. Finally, even though no head rotation movements were observed during the stimulation period, we viewed a relationship between the duration of stimulation and the neck forces exerted by the monkey’s head. We propose an updated vision of the PEEF composed of two functional regions, core and belt, which may be involved in integrating auditory and visual information important to the programming of gaze

  2. Visual-Motor Transformations Within Frontal Eye Fields During Head-Unrestrained Gaze Shifts in the Monkey.

    Science.gov (United States)

    Sajad, Amirsaman; Sadeh, Morteza; Keith, Gerald P; Yan, Xiaogang; Wang, Hongying; Crawford, John Douglas

    2015-10-01

    A fundamental question in sensorimotor control concerns the transformation of spatial signals from the retina into eye and head motor commands required for accurate gaze shifts. Here, we investigated these transformations by identifying the spatial codes embedded in visually evoked and movement-related responses in the frontal eye fields (FEFs) during head-unrestrained gaze shifts. Monkeys made delayed gaze shifts to the remembered location of briefly presented visual stimuli, with delay serving to dissociate visual and movement responses. A statistical analysis of nonparametric model fits to response field data from 57 neurons (38 with visual and 49 with movement activities) eliminated most effector-specific, head-fixed, and space-fixed models, but confirmed the dominance of eye-centered codes observed in head-restrained studies. More importantly, the visual response encoded target location, whereas the movement response mainly encoded the final position of the imminent gaze shift (including gaze errors). This spatiotemporal distinction between target and gaze coding was present not only at the population level, but even at the single-cell level. We propose that an imperfect visual-motor transformation occurs during the brief memory interval between perception and action, and further transformations from the FEF's eye-centered gaze motor code to effector-specific codes in motor frames occur downstream in the subcortical areas.

  3. Direct evidence for attention-dependent influences of the frontal eye-fields on feature-responsive visual cortex.

    Science.gov (United States)

    Heinen, Klaartje; Feredoes, Eva; Weiskopf, Nikolaus; Ruff, Christian C; Driver, Jon

    2014-11-01

    Voluntary selective attention can prioritize different features in a visual scene. The frontal eye-fields (FEF) are one potential source of such feature-specific top-down signals, but causal evidence for influences on visual cortex (as was shown for "spatial" attention) has remained elusive. Here, we show that transcranial magnetic stimulation (TMS) applied to right FEF increased the blood oxygen level-dependent (BOLD) signals in visual areas processing "target feature" but not in "distracter feature"-processing regions. TMS-induced BOLD signals increase in motion-responsive visual cortex (MT+) when motion was attended in a display with moving dots superimposed on face stimuli, but in face-responsive fusiform area (FFA) when faces were attended to. These TMS effects on BOLD signal in both regions were negatively related to performance (on the motion task), supporting the behavioral relevance of this pathway. Our findings provide new causal evidence for the human FEF in the control of nonspatial "feature"-based attention, mediated by dynamic influences on feature-specific visual cortex that vary with the currently attended property.

  4. Neural Control of Voluntary Eye Closure: A Case Study and an fMRI Investigation of Blinking and Winking

    Directory of Open Access Journals (Sweden)

    Martijn G. van Koningsbruggen

    2012-01-01

    Full Text Available The current paper describes a rare case of a patient who suffered from unilateral apraxia of eye closure as a result of a bilateral stroke. Interestingly, the patient’s ability to voluntarily close both eyelids (i.e. blinking was not affected, indicating that different neural mechanisms control each type of eye closure. The stroke caused damage to a large part of the right frontal cortex, including the motor cortex, pre-motor cortex and the frontal eye field (FEF. The lesion in the left hemisphere was restricted to the FEF. In order to further study the neural mechanisms of eye closure, we conducted an fMRI study in a group of neurological healthy subjects. We found that all areas of the oculomotor cortex were activated by both left and right winking, including the FEF, supplementary eye field (SEF, and posterior parietal cortex (PPC. Blinking activated FEF and SEF, but not PPC. Both FEF and PPC were significantly more active during winking than blinking. Together, these results provide evidence for a critical role of the FEF in voluntary unilateral eye closure.

  5. Familial aggregation of FEF25–75 and FEF25–75/FVC in families with severe, early onset COPD

    Science.gov (United States)

    DeMeo, D; Carey, V; Chapman, H; Reilly, J; Ginns, L; Speizer, F; Weiss, S; Silverman, E

    2004-01-01

    Background: The Boston Early-Onset COPD study showed that current or ex-smoking first degree relatives of severe early onset COPD probands have significantly lower forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC) values than current or ex-smoking control subjects, which suggests the existence of genetic risk factors for the development of COPD in response to cigarette smoking. We hypothesised that first degree relatives of early onset COPD probands may also have lower values of spirometric parameters such as forced expiratory flow at the mid-portion of forced vital capacity (FEF25–75) and FEF25–75/FVC. Methods: Using generalised estimating equations, FEF25–75 and FEF25–75/FVC were analysed in 333 first degree relatives of probands with severe early onset COPD and 83 population based controls; analyses were also performed on data stratified by smoking status. Narrow sense heritability estimates were calculated using a variance component approach. Results: Significantly lower FEF25–75 and FEF25–75/FVC were observed in smoking (FEF25–75: ß –0.788 l/s (95% CI –1.118 to –0.457), FEF25–75/FVC: ß –20.4% (95% CI –29.3 to –11.6, p<0.0001 for both phenotypes) and non-smoking (FEF25–75: ß –0.357 l/s (95% CI –0.673 to –0.041, p = 0.0271), FEF25–75/FVC: ß –9.5% (95% CI –17.1 to –1.9, p = 0.0145)) first degree relatives of early onset COPD probands. Narrow sense heritability estimates for FEF25–75 (h2 = 0.38) and FEF25–75/FVC (h2 = 0.45) were similar to those for FEV1 and FEV1/FVC. Conclusion: Lower values of FEF25–75 and FEF25–75/FVC in non-smoking first degree relatives of early onset COPD probands than in controls suggest a genetic susceptibility to develop obstructive lung disease, independent of smoking, which is magnified by exposure to deleterious environments as suggested by the further decrements in FEF25–75 and FEF25–75/FVC seen in smoking first degree relatives. FEF25–75 and

  6. Familial aggregation of FEF(25-75) and FEF(25-75)/FVC in families with severe, early onset COPD.

    Science.gov (United States)

    DeMeo, D L; Carey, V J; Chapman, H A; Reilly, J J; Ginns, L C; Speizer, F E; Weiss, S T; Silverman, E K

    2004-05-01

    The Boston Early-Onset COPD study showed that current or ex-smoking first degree relatives of severe early onset COPD probands have significantly lower forced expiratory volume in 1 second (FEV(1)) and FEV(1)/forced vital capacity (FVC) values than current or ex-smoking control subjects, which suggests the existence of genetic risk factors for the development of COPD in response to cigarette smoking. We hypothesised that first degree relatives of early onset COPD probands may also have lower values of spirometric parameters such as forced expiratory flow at the mid-portion of forced vital capacity (FEF(25-75)) and FEF(25-75)/FVC. Using generalised estimating equations, FEF(25-75) and FEF(25-75)/FVC were analysed in 333 first degree relatives of probands with severe early onset COPD and 83 population based controls; analyses were also performed on data stratified by smoking status. Narrow sense heritability estimates were calculated using a variance component approach. Significantly lower FEF(25-75) and FEF(25-75)/FVC were observed in smoking (FEF(25-75): beta -0.788 l/s (95% CI -1.118 to -0.457), FEF(25-75)/FVC: beta -20.4% (95% CI -29.3 to -11.6, p<0.0001 for both phenotypes) and non-smoking (FEF(25-75): beta -0.357 l/s (95% CI -0.673 to -0.041, p = 0.0271), FEF(25-75)/FVC: beta -9.5% (95% CI -17.1 to -1.9, p = 0.0145)) first degree relatives of early onset COPD probands. Narrow sense heritability estimates for FEF(25-75) (h(2) = 0.38) and FEF(25-75)/FVC (h(2) = 0.45) were similar to those for FEV(1) and FEV(1)/FVC. Lower values of FEF(25-75) and FEF(25-75)/FVC in non-smoking first degree relatives of early onset COPD probands than in controls suggest a genetic susceptibility to develop obstructive lung disease, independent of smoking, which is magnified by exposure to deleterious environments as suggested by the further decrements in FEF(25-75) and FEF(25-75)/FVC seen in smoking first degree relatives. FEF(25-75) and FEF(25-75)/FVC have high heritability and are

  7. Saccade generation by the frontal eye fields in rhesus monkeys is separable from visual detection and bottom-up attention shift.

    Science.gov (United States)

    Lee, Kyoung-Min; Ahn, Kyung-Ha; Keller, Edward L

    2012-01-01

    The frontal eye fields (FEF), originally identified as an oculomotor cortex, have also been implicated in perceptual functions, such as constructing a visual saliency map and shifting visual attention. Further dissecting the area's role in the transformation from visual input to oculomotor command has been difficult because of spatial confounding between stimuli and responses and consequently between intermediate cognitive processes, such as attention shift and saccade preparation. Here we developed two tasks in which the visual stimulus and the saccade response were dissociated in space (the extended memory-guided saccade task), and bottom-up attention shift and saccade target selection were independent (the four-alternative delayed saccade task). Reversible inactivation of the FEF in rhesus monkeys disrupted, as expected, contralateral memory-guided saccades, but visual detection was demonstrated to be intact at the same field. Moreover, saccade behavior was impaired when a bottom-up shift of attention was not a prerequisite for saccade target selection, indicating that the inactivation effect was independent of the previously reported dysfunctions in bottom-up attention control. These findings underscore the motor aspect of the area's functions, especially in situations where saccades are generated by internal cognitive processes, including visual short-term memory and long-term associative memory.

  8. Saccade generation by the frontal eye fields in rhesus monkeys is separable from visual detection and bottom-up attention shift.

    Directory of Open Access Journals (Sweden)

    Kyoung-Min Lee

    Full Text Available The frontal eye fields (FEF, originally identified as an oculomotor cortex, have also been implicated in perceptual functions, such as constructing a visual saliency map and shifting visual attention. Further dissecting the area's role in the transformation from visual input to oculomotor command has been difficult because of spatial confounding between stimuli and responses and consequently between intermediate cognitive processes, such as attention shift and saccade preparation. Here we developed two tasks in which the visual stimulus and the saccade response were dissociated in space (the extended memory-guided saccade task, and bottom-up attention shift and saccade target selection were independent (the four-alternative delayed saccade task. Reversible inactivation of the FEF in rhesus monkeys disrupted, as expected, contralateral memory-guided saccades, but visual detection was demonstrated to be intact at the same field. Moreover, saccade behavior was impaired when a bottom-up shift of attention was not a prerequisite for saccade target selection, indicating that the inactivation effect was independent of the previously reported dysfunctions in bottom-up attention control. These findings underscore the motor aspect of the area's functions, especially in situations where saccades are generated by internal cognitive processes, including visual short-term memory and long-term associative memory.

  9. Mössbauer study of an amorphous iron III flouride: FeF 3, xHF (0 ⩽ x ⩽ 1)

    Science.gov (United States)

    Greneche, J. M.; Varret, F.; Leblanc, M.; Ferey, G.

    1987-08-01

    A ferric amorphous flouride FeF 3, xHF with 0 ⩽ x ⩽ 1 synthesized by a soft chemistry reaction was studied by Mössbauer spectroscopy. The hyperfine characteristics are very close to those of deposited variety previously published: they show that the Fe 3+ ions are surrounded by weakly distorted octahedra of flourine atoms. The study under external magnetic field indicates that the spins are randomly distributed: FeF 3, xHF has a speromagnetic behaviour like deposited amorphous FeF 3. Elsewhere the similarity between the two amorphous forms is confirmed by susceptibility measurements.

  10. Functional activity within the frontal eye fields, posterior parietal cortex and cerebellar vermis significantly correlates to symmetrical vergence peak velocity: An ROI-based, fMRI study of vergence training

    Directory of Open Access Journals (Sweden)

    Tara L Alvarez

    2014-06-01

    Full Text Available Convergence insufficiency (CI is a prevalent binocular vision disorder with symptoms that include double/blurred vision, eyestrain, and headaches when engaged in reading or other near work. Randomized clinical trials support that Office-Based Vergence and Accommodative Therapy with home reinforcement leads to a sustained reduction in patient symptoms. However, the underlying neurophysiological basis for treatment is unknown. Functional activity and vergence eye movements were quantified from seven binocularly normal controls (BNC and four CI patients before and after 18 hours of vergence training. An fMRI conventional block design of sustained fixation versus vergence eye movements stimulated activity in the frontal eye fields (FEF, the posterior parietal cortex (PPC and the cerebellar vermis (CV. Comparing the CI patients’ baseline measurements to the post vergence training data sets with a paired t-test revealed the following: 1 the percent change in the BOLD signal in the FEF, PPC and CV significantly increased (p<0.02, 2 the peak velocity from 4° symmetrical convergence step responses increased (p<0.01 and 3 patient symptoms assessed using the CI Symptom Survey (CISS improved (p<0.05. CI patient measurements after vergence training were more similar to levels observed within BNC. A regression analysis revealed the peak velocity from BNC and CI subjects before and after vergence training was significantly correlated to the percent BOLD signal change within the FEF, PPC and CV (r=0.6;p<0.05. Results have clinical implications for understanding the behavioral and neurophysiological changes after vergence training in patients with CI, which may lead to the sustained reduction in visual symptoms.

  11. Refractive sectors in the visual field of the pigeon eye.

    Science.gov (United States)

    Fitzke, F W; Hayes, B P; Hodos, W; Holden, A L; Low, J C

    1985-12-01

    Scheiner's principle has been used in electroretinographic optometry to refract the photoreceptor plane in different regions of the visual field of the pigeon eye. Along the horizon and in the upper visual field the eye is emmetropic, or nearly so. Below the horizon the eye becomes progressively more myopic at more negative elevations, refractive state falling to -5D at -90 deg. Lower field myopia is not an artifact of oblique astigmatism, nor of an aberration symmetrical about the optical axis. It is suggested that lower field myopia is a biological adaptation suited to keep the photoreceptors in the upper retina conjugate with the ground. Refractive state below the horizon can be fitted with a sine function by varying a parameter H (eye-ground height). The value of H agrees well with directly measured eye-ground height.

  12. Hawk eyes I: diurnal raptors differ in visual fields and degree of eye movement.

    Directory of Open Access Journals (Sweden)

    Colleen T O'Rourke

    Full Text Available BACKGROUND: Different strategies to search and detect prey may place specific demands on sensory modalities. We studied visual field configuration, degree of eye movement, and orbit orientation in three diurnal raptors belonging to the Accipitridae and Falconidae families. METHODOLOGY/PRINCIPAL FINDINGS: We used an ophthalmoscopic reflex technique and an integrated 3D digitizer system. We found inter-specific variation in visual field configuration and degree of eye movement, but not in orbit orientation. Red-tailed Hawks have relatively small binocular areas (∼33° and wide blind areas (∼82°, but intermediate degree of eye movement (∼5°, which underscores the importance of lateral vision rather than binocular vision to scan for distant prey in open areas. Cooper's Hawks' have relatively wide binocular fields (∼36°, small blind areas (∼60°, and high degree of eye movement (∼8°, which may increase visual coverage and enhance prey detection in closed habitats. Additionally, we found that Cooper's Hawks can visually inspect the items held in the tip of the bill, which may facilitate food handling. American Kestrels have intermediate-sized binocular and lateral areas that may be used in prey detection at different distances through stereopsis and motion parallax; whereas the low degree eye movement (∼1° may help stabilize the image when hovering above prey before an attack. CONCLUSIONS: We conclude that: (a there are between-species differences in visual field configuration in these diurnal raptors; (b these differences are consistent with prey searching strategies and degree of visual obstruction in the environment (e.g., open and closed habitats; (c variations in the degree of eye movement between species appear associated with foraging strategies; and (d the size of the binocular and blind areas in hawks can vary substantially due to eye movements. Inter-specific variation in visual fields and eye movements can influence

  13. Spin waves in antiferromagnetic FeF2

    DEFF Research Database (Denmark)

    Hutchings, M T; Rainford, B.D.; Guggenheim, H J

    1970-01-01

    Spin-wave dispersion in antiferromagnetic FeF2 has been investigated by inelastic neutron scattering using a chopper time-of-flight spectrometer. The single mode observed has a relatively flat dispersion curve rising from 53 cm-1 at the zone centre to 79 cm-1 at the zone boundary. A spin Hamilton......Spin-wave dispersion in antiferromagnetic FeF2 has been investigated by inelastic neutron scattering using a chopper time-of-flight spectrometer. The single mode observed has a relatively flat dispersion curve rising from 53 cm-1 at the zone centre to 79 cm-1 at the zone boundary. A spin...

  14. Vestibular-related frontal cortical areas and their roles in smooth-pursuit eye movements: representation of neck velocity, neck-vestibular interactions and memory-based smooth-pursuit

    Directory of Open Access Journals (Sweden)

    Kikuro eFukushima

    2011-12-01

    Full Text Available Smooth-pursuit eye movements are voluntary responses to small slow-moving objects in the fronto-parallel plane. They evolved in primates, who possess high-acuity foveae, to ensure clear vision about the moving target. The primate frontal cortex contains two smooth-pursuit related areas; the caudal part of the frontal eye fields (FEF and the supplementary eye fields (SEF. Both areas receive vestibular inputs. We review functional differences between the two areas in smooth-pursuit. Most FEF pursuit neurons signal pursuit parameters such as eye velocity and gaze-velocity, and are involved in cancelling the vestibulo-ocular reflex by linear addition of vestibular and smooth-pursuit responses. In contrast, gaze-velocity signals are rarely represented in the SEF. Most FEF pursuit neurons receive neck velocity inputs, while discharge modulation during pursuit and trunk-on-head rotation adds linearly. Linear addition also occurs between neck velocity responses and vestibular responses during head-on-trunk rotation in a task-dependent manner. During cross-axis pursuit-vestibular interactions, vestibular signals effectively initiate predictive pursuit eye movements. Most FEF pursuit neurons discharge during the interaction training after the onset of pursuit eye velocity, making their involvement unlikely in the initial stages of generating predictive pursuit. Comparison of representative signals in the two areas and the results of chemical inactivation during a memory-based smooth-pursuit task indicate they have different roles; the SEF plans smooth-pursuit including working memory of motion-direction, whereas the caudal FEF generates motor commands for pursuit eye movements. Patients with idiopathic Parkinson’s disease were asked to perform this task, since impaired smooth-pursuit and visual working memory deficit during cognitive tasks have been reported in most patients. Preliminary results suggested specific roles of the basal ganglia in memory

  15. MODELLING SYNERGISTIC EYE MOVEMENTS IN THE VISUAL FIELD

    Directory of Open Access Journals (Sweden)

    BARITZ Mihaela

    2015-06-01

    Full Text Available Some theoretical and practical considerations about eye movements in visual field are presented in the first part of this paper. These movements are developed into human body to be synergistic and are allowed to obtain the visual perception in 3D space. The theoretical background of the eye movements’ analysis is founded on the establishment of movement equations of the eyeball, as they consider it a solid body with a fixed point. The exterior actions, the order and execution of the movements are ensured by the neural and muscular external system and thus the position, stability and movements of the eye can be quantified through the method of reverse kinematic. The purpose of these researches is the development of a simulation model of human binocular visual system, an acquisition methodology and an experimental setup for data processing and recording regarding the eye movements, presented in the second part of the paper. The modeling system of ocular movements aims to establish the binocular synergy and limits of visual field changes in condition of ocular motor dysfunctions. By biomechanical movements of eyeball is established a modeling strategy for different sort of processes parameters like convergence, fixation and eye lens accommodation to obtain responses from binocular balance. The results of modelling processes and the positions of eye ball and axis in visual field are presented in the final part of the paper.

  16. Mössbauer Study of Relaxation Phenomena in (NH4)3FeF6

    DEFF Research Database (Denmark)

    Mørup, Steen; Thrane, N.

    1973-01-01

    The shape of a relaxation-broadened Mössbauer absorption line for a paramagnetic ferric compound is influenced by various terms of the ionic Hamiltonian. Here we discuss especially how the application of an external magnetic field may influence the line shape and may give information about...... the magnitudes of other terms of the ionic Hamiltonian. Measurements on the two phases of (NH4)3FeF6 demonstrate differences between cubic and noncubic surroundings of the ferric ion. In the cubic phase we have found a temperature-independent spin-correlation time τ≃1.19×10-10 sec....

  17. Shaping magnetic fields to direct therapy to ears and eyes.

    Science.gov (United States)

    Shapiro, B; Kulkarni, S; Nacev, A; Sarwar, A; Preciado, D; Depireux, D A

    2014-07-11

    Magnetic fields have the potential to noninvasively direct and focus therapy to disease targets. External magnets can apply forces on drug-coated magnetic nanoparticles, or on living cells that contain particles, and can be used to manipulate them in vivo. Significant progress has been made in developing and testing safe and therapeutic magnetic constructs that can be manipulated by magnetic fields. However, we do not yet have the magnet systems that can then direct those constructs to the right places, in vivo, over human patient distances. We do not yet know where to put the external magnets, how to shape them, or when to turn them on and off to direct particles or magnetized cells-in blood, through tissue, and across barriers-to disease locations. In this article, we consider ear and eye disease targets. Ear and eye targets are too deep and complex to be targeted by a single external magnet, but they are shallow enough that a combination of magnets may be able to direct therapy to them. We focus on how magnetic fields should be shaped (in space and time) to direct magnetic constructs to ear and eye targets.

  18. Effect of graphene on far-infrared transmission and absorption of FeF2 photonic crystals

    Science.gov (United States)

    Gao, Ying; Zhou, Sheng; Fu, Shufang

    2017-10-01

    The influence of graphene (Gr) on the far-infrared transmission and absorption of FeF2 photonic crystals (PCs) is investigated by the forth-order transfer matrix since Gr is anisotropic when the external field is perpendicular to the surface of PCs. The numerical results show that the transmission and absorption spectra largely depend on the structural symmetry of Gr/FeF2 PCs and the position of Gr layer. The optimal structure and number of dielectric bi-layers (N) are discussed. In addition, the introduction of Gr leads to the disappearance of the defect modes in the band gap. Meanwhile, the line width of absorption around of the resonant frequencies of FeF2 has been extremely broadened, which is compared with the one of FeF2 PCs. Once N is beyond a critical value, the absorber will become the reflector. The effect of Fermi energy and external field on the absorption is also investigated.

  19. Coordinating one hand with two eyes: optimizing for field of view in a pointing task.

    Science.gov (United States)

    Khan, Aarlenne Z; Crawford, J Douglas

    2003-02-01

    We previously found that subjects switched 'ocular dominance' as a function of horizontal gaze direction in a reaching task [Vision Res. 41 (14) (2001) 1743]. Here we extend these findings to show that when subjects pointed to targets across the horizontal binocular field, they aligned the fingertip with a vertical plane located between the eyes and the target. This eye-target plane gradually shifted from aligning with the left eye (leftward targets) to between the two eyes (intermediate targets) to the right eye (rightward targets). We suggest that this occurs to optimize eye-hand alignment towards the eye with the best overall field of view.

  20. Atomistic simulations of the Fe K-edge EXAFS in FeF3 using molecular dynamics and reverse Monte Carlo methods

    Science.gov (United States)

    Jonane, Inga; Timoshenko, Janis; Kuzmin, Alexei

    2016-10-01

    Atomistic simulations of the experimental Fe K-edge extended x-ray absorption fine structure (EXAFS) of rhombohedral (space group R\\bar{3}c) FeF3 at T = 300 K were performed using classical molecular dynamics and reverse Monte Carlo (RMC) methods. The use of two complementary theoretical approaches allowed us to account accurately for thermal disorder effects in EXAFS and to validate the developed force-field model, which was constructed as a sum of two-body Buckingham-type (Fe-F and F-F), three-body harmonic (Fe-F-Fe) and Coulomb potentials. We found that the shape of the Fe K-edge EXAFS spectrum of FeF3 is a more sensitive probe for the determination of potential parameters than the values of structural parameters (a, c, x(F)) available from diffraction studies. The best overall agreement between the experimental and theoretical EXAFS spectra calculated using ab initio multiple-scattering approach was obtained for the iron effective charge q(Fe) = 1.71. The RMC method coupled with the evolutionary algorithm was used for more elaborate analysis of the EXAFS data. The obtained results suggest that our force-field model slightly underestimates the amplitude of thermal vibrations of fluorine atoms in the direction perpendicular to the Fe-F bonds.

  1. Distinct cis-acting regions control six6 expression during eye field and optic cup stages of eye formation.

    Science.gov (United States)

    Ledford, Kelley L; Martinez-De Luna, Reyna I; Theisen, Matthew A; Rawlins, Karisa D; Viczian, Andrea S; Zuber, Michael E

    2017-06-15

    The eye field transcription factor, Six6, is essential for both the early (specification and proliferative growth) phase of eye formation, as well as for normal retinal progenitor cell differentiation. While genomic regions driving six6 optic cup expression have been described, the sequences controlling eye field and optic vesicle expression are unknown. Two evolutionary conserved regions 5' and a third 3' to the six6 coding region were identified, and together they faithfully replicate the endogenous X. laevis six6 expression pattern. Transgenic lines were generated and used to determine the onset and expression patterns controlled by the regulatory regions. The conserved 3' region was necessary and sufficient for eye field and optic vesicle expression. In contrast, the two conserved enhancer regions located 5' of the coding sequence were required together for normal optic cup and mature retinal expression. Gain-of-function experiments indicate endogenous six6 and GFP expression in F1 transgenic embryos are similarly regulated in response to candidate trans-acting factors. Importantly, CRISPR/CAS9-mediated deletion of the 3' eye field/optic vesicle enhancer in X. laevis, resulted in a reduction in optic vesicle size. These results identify the cis-acting regions, demonstrate the modular nature of the elements controlling early versus late retinal expression, and identify potential regulators of six6 expression during the early stages of eye formation. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. [Brodmann Areas 8 and 9 Including the Frontal Eye Field].

    Science.gov (United States)

    Watanabe, Masataka

    2017-04-01

    Based on cytoarchitectonic analyses, Brodmann assigned numbers 8 and 9 to certain areas of the dorsal and medial prefrontal cortex (PFC) in humans and monkeys. Petrides and Pandya re-analyzed the cytoarchitectures of the human and monkey PFCs, and proposed slightly different brain maps for both species. They assigned numbers 8, 9 and 9/46 to the areas that were originally named areas 8 and 9. Areas 8 and 9 have both lateral and medial regions respectively. The lateral area 8 is important for conditional discrimination learning. The frontal eye field which occupies the most caudal region of area 8, is responsible for visual attention and control of eye movements. The lateral area 9 and area 9/46 are functionally similar to area 46 and play important roles in executive control. The dorsomedial prefrontal cortex (DMPFC) comprises the medial regions of areas 8 and 9 and is related to "Theory of Mind" and social cognition. The DMPFC is also known to show "default mode of brain activity" (i.e., more activity during rest than during cognitive task).

  3. Neural network evidence for the coupling of presaccadic visual remapping to predictive eye position updating

    Directory of Open Access Journals (Sweden)

    Hrishikesh M Rao

    2016-06-01

    Full Text Available As we look around a scene, we perceive it as continuous and stable even though each saccadic eye movement changes the visual input to the retinas. How the brain achieves this perceptual stabilization is unknown, but a major hypothesis is that it relies on presaccadic remapping, a process in which neurons shift their visual sensitivity to a new location in the scene just before each saccade. This hypothesis is difficult to test in vivo because complete, selective inactivation of remapping is currently intractable. We tested it in silico with a hierarchical, sheet-based neural network model of the visual and oculomotor system. The model generated saccadic commands to move a video camera abruptly. Visual input from the camera and internal copies of the saccadic movement commands, or corollary discharge, converged at a map-level simulation of the frontal eye field (FEF, a primate brain area known to receive such inputs. FEF output was combined with eye position signals to yield a suitable coordinate frame for guiding arm movements of a robot. Our operational definition of perceptual stability was useful stability, quantified as continuously accurate pointing to a visual object despite camera saccades. During training, the emergence of useful stability was correlated tightly with the emergence of presaccadic remapping in the FEF. Remapping depended on corollary discharge but its timing was synchronized to the updating of eye position. When coupled to predictive eye position signals, remapping served to stabilize the target representation for continuously accurate pointing. Graded inactivations of pathways in the model replicated, and helped to interpret, previous in vivo experiments. The results support the hypothesis that visual stability requires presaccadic remapping, provide explanations for the function and timing of remapping, and offer testable hypotheses for in vivo studies. We conclude that remapping allows for seamless coordinate frame

  4. Characteristics of eye-position gain field populations determine geometry of visual space

    Directory of Open Access Journals (Sweden)

    Sidney R Lehky

    2016-01-01

    Full Text Available We have previously demonstrated differences in eye-position spatial maps for anterior inferotemporal cortex (AIT in the ventral stream and lateral intraparietal cortex (LIP in the dorsal stream, based on population decoding of gaze angle modulations of neural visual responses (i.e., eye-position gain fields. Here we explore the basis of such spatial encoding differences through modeling of gain field characteristics. We created a population of model neurons, each having a different eye-position gain field. This population was used to reconstruct eye-position visual space using multidimensional scaling. As gain field shapes have never been well established experimentally, we examined different functions, including planar, sigmoidal, elliptical, hyperbolic, and mixtures of those functions. All functions successfully recovered positions, indicating weak constraints on allowable gain field shapes. We then used a genetic algorithm to modify the characteristics of model gain field populations until the recovered spatial maps closely matched those derived from monkey neurophysiological data in AIT and LIP. The primary differences found between model AIT and LIP gain fields were that AIT gain fields were more foveally dominated. That is, gain fields in AIT operated on smaller spatial scales and smaller dispersions than in LIP. Thus we show that the geometry of eye-position visual space depends on the population characteristics of gain fields, and that differences in gain field characteristics for different cortical areas may underlie differences in the representation of space.

  5. Hydrogen storage in Mg-LiBH4 composites catalyzed by FeF3

    Science.gov (United States)

    Puszkiel, Julián; Gennari, Fabiana C.; Arneodo Larochette, Pierre; Troiani, Horacio E.; Karimi, Fahim; Pistidda, Claudio; Gosalawit-Utke, Rapee; Jepsen, Julian; Jensen, Torben R.; Gundlach, Carsten; Tolkiehn, Martin; Bellosta von Colbe, José; Klassen, Thomas; Dornheim, Martin

    2014-12-01

    Mg-10 mol% LiBH4 composite plus small amounts of FeF3 is investigated in the present work. The presence of LiBH4 during the milling process noticeably modifies the size and morphology of the Mg agglomerates, leading to faster hydrogenation and reaching almost the theoretical hydrogen capacity owing to enhanced hydrogen diffusion mechanism. However, the dehydrogenation of the system at low temperatures (≤300 °C) is still slow. Thus, FeF3 addition is proposed to improve the dehydrogenation kinetic behavior. From experimental results, it is found that the presence of FeF3 results in an additional size reduction of the Mg agglomerates between ∼10 and ∼100 μm and the formation of stable phases such as MgF2, LiF and FeB. The FeB species might have a catalytic effect upon the MgH2 decomposition. As a further result of the FeF3 addition, the Mg-10 mol%LiBH4-5 mol% FeF3 material shows improved dehydrogenation properties: reduced dehydrogenation activation energy, faster hydrogen desorption rate and reversible hydrogen capacities of about 5 wt% at 275 °C.

  6. In Situ Engineering Toward Core Regions: A Smart Way to Make Applicable FeF3@Carbon Nanoreactor Cathodes for Li-Ion Batteries.

    Science.gov (United States)

    Li, Linpo; Zhu, Jianhui; Xu, Maowen; Jiang, Jian; Li, Chang Ming

    2017-05-31

    Iron fluorides (FeFx) have attracted great interest in Li-ion batteries due to their high theoretical capacity, low cost, and preferable cell safety. However, their practical utilization is severely impeded by inferior electrode kinetics, leading to poor electrode cyclability and rate capabilities. The major bottleneck should be lack of any effective engineering techniques to make reliable encapsulation and conducting matrix on soluble FeFx species. Herein, we propose an applicable synthetic strategy where the massive production of FeF3@carbon nanoreactors (total size: ∼60 nm) can be easily achieved by in situ engineering toward the core regions in hybrids, with the iron rust wastes and common solvents as raw materials. Such functionalized configurations can well make up for the shortcomings of FeF3 species, enabling them with outstanding cathode behaviors involving excellent reversible capacity retention (∼270% higher than that of a bare FeF3 electrode after 600 cycles) and drastically enhanced rate performance. This paradigm work provides a facile and scalable method to make superior and sustainable cathodes and, moreover, offers a feasible engineering protocol to make water-soluble species encapsulated into carbon matrix, not merely for batteries but also for other wide range of fields like catalysis, nanomedicine, etc.

  7. The subtlety of simple eyes: the tuning of visual fields to perceptual challenges in birds.

    Science.gov (United States)

    Martin, Graham R

    2014-01-01

    Birds show interspecific variation both in the size of the fields of individual eyes and in the ways that these fields are brought together to produce the total visual field. Variation is found in the dimensions of all main parameters: binocular region, cyclopean field and blind areas. There is a phylogenetic signal with respect to maximum width of the binocular field in that passerine species have significantly broader field widths than non-passerines; broadest fields are found among crows (Corvidae). Among non-passerines, visual fields show considerable variation within families and even within some genera. It is argued that (i) the main drivers of differences in visual fields are associated with perceptual challenges that arise through different modes of foraging, and (ii) the primary function of binocularity in birds lies in the control of bill position rather than in the control of locomotion. The informational function of binocular vision does not lie in binocularity per se (two eyes receiving slightly different information simultaneously about the same objects from which higher-order depth information is extracted), but in the contralateral projection of the visual field of each eye. Contralateral projection ensures that each eye receives information from a symmetrically expanding optic flow-field from which direction of travel and time to contact targets can be extracted, particularly with respect to the control of bill position.

  8. Moonwalk with Your Eyes A Pocket Field Guide

    CERN Document Server

    Plotner, Tammy

    2010-01-01

    Are you ready to take a quarter of a million mile journey with just your eyes? Then welcome to "Moon Walk with Your Eyes"! We often take the beauty of our nearest astronomical neighbor for granted. How often do we really stop to think about why it looks the way it does or what a closer look will reveal? In this book, written in easy-to-understand language by one backyard astronomer to another, we'll explore the Moon night by night, as it goes through a full cycle. Every lunar day has something new to learn! And along your journey, you will be reading about the history, mystery, poetry, and legends that are associated with our Moon. Charts will help guide you to specific lunar features, as well as annotated photographic maps that pinpoint important or unusual craters. You'll soon learn to identify major features at just a glance and be able to create your own world-class images. You'll have right at hand the times and dates for every lunar day, phase, and eclipse for years to come. Imagine yourself at the tele...

  9. Eye torsion and the apparent horizon under head tilt and visual field rotation

    Science.gov (United States)

    Merker, B. H.; Held, R.

    1981-01-01

    Two different experimental manipulations, namely head tilt and the viewing of a visual display rotating around the line of sight, induce torsional displacements of the eyes and a tilting of the apparent horizon. The present study examines the routes by which visual (field rotation) and otolith-proprioceptive (head tilt) sources of afference influence horizon judgments. In particular, the relationship between torsional eye movements and horizon estimates is addressed. The results indicate that visual and otolith-proprioceptive information sum directly in their influence on eye torsion, but interact more complexly in horizon estimates, indicating a dissociation of their central determinants.

  10. The effect of visual field defects on eye movements and practical fitness to drive

    NARCIS (Netherlands)

    Coeckelbergh, TRM; Cornelissen, FW; Brouwer, WH; Kooijman, AC

    Eye movements Of Subjects with visual field defects due to ocular pathology were monitored while performing a dot counting task and a visual search task. Subjects with peripheral field defects required more fixations, longer search times, made more errors. and had shorter fixation durations than

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

    Science.gov (United States)

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

    2012-03-01

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

  12. Transverse chromatic aberration across the visual field of the human eye.

    Science.gov (United States)

    Winter, Simon; Sabesan, Ramkumar; Tiruveedhula, Pavan; Privitera, Claudio; Unsbo, Peter; Lundström, Linda; Roorda, Austin

    2016-11-01

    The purpose of this study was to measure the transverse chromatic aberration (TCA) across the visual field of the human eye objectively. TCA was measured at horizontal and vertical field angles out to ±15° from foveal fixation in the right eye of four subjects. Interleaved retinal images were taken at wavelengths 543 nm and 842 nm in an adaptive optics scanning laser ophthalmoscope (AOSLO). To obtain true measures of the human eye's TCA, the contributions of the AOSLO system's TCA were measured using an on-axis aligned model eye and subtracted from the ocular data. The increase in TCA was found to be linear with eccentricity, with an average slope of 0.21 arcmin/degree of visual field angle (corresponding to 0.41 arcmin/degree for 430 nm to 770 nm). The absolute magnitude of ocular TCA varied between subjects, but was similar to the resolution acuity at 10° in the nasal visual field, encompassing three to four cones. Therefore, TCA can be visually significant. Furthermore, for high-resolution imaging applications, whether visualizing or stimulating cellular features in the retina, it is important to consider the lateral displacements between wavelengths and the variation in blur over the visual field.

  13. Eye-centered visual receptive fields in the ventral intraparietal area.

    Science.gov (United States)

    Chen, Xiaodong; DeAngelis, Gregory C; Angelaki, Dora E

    2014-07-15

    The ventral intraparietal area (VIP) processes multisensory visual, vestibular, tactile, and auditory signals in diverse reference frames. We recently reported that visual heading signals in VIP are represented in an approximately eye-centered reference frame when measured using large-field optic flow stimuli. No VIP neuron was found to have head-centered visual heading tuning, and only a small proportion of cells had reference frames that were intermediate between eye- and head-centered. In contrast, previous studies using moving bar stimuli have reported that visual receptive fields (RFs) in VIP are head-centered for a substantial proportion of neurons. To examine whether these differences in previous findings might be due to the neuronal property examined (heading tuning vs. RF measurements) or the type of visual stimulus used (full-field optic flow vs. a single moving bar), we have quantitatively mapped visual RFs of VIP neurons using a large-field, multipatch, random-dot motion stimulus. By varying eye position relative to the head, we tested whether visual RFs in VIP are represented in head- or eye-centered reference frames. We found that the vast majority of VIP neurons have eye-centered RFs with only a single neuron classified as head-centered and a small minority classified as intermediate between eye- and head-centered. Our findings suggest that the spatial reference frames of visual responses in VIP may depend on the visual stimulation conditions used to measure RFs and might also be influenced by how attention is allocated during stimulus presentation.

  14. The GIPC1-Akt1 Pathway Is Required for the Specification of the Eye Field in Mouse Embryonic Stem Cells.

    Science.gov (United States)

    La Torre, Anna; Hoshino, Akina; Cavanaugh, Christopher; Ware, Carol B; Reh, Thomas A

    2015-09-01

    During early patterning of the neural plate, a single region of the embryonic forebrain, the eye field, becomes competent for eye development. The hallmark of eye field specification is the expression of the eye field transcription factors (EFTFs). Experiments in fish, amphibians, birds, and mammals have demonstrated largely conserved roles for the EFTFs. Although some of the key signaling events that direct the synchronized expression of these factors to the eye field have been elucidated in fish and frogs, it has been more difficult to study these mechanisms in mammalian embryos. In this study, we have used two different methods for directed differentiation of mouse embryonic stem cells (mESCs) to generate eye field cells and retina in vitro to test for a role of the PDZ domain-containing protein GIPC1 in the specification of the mammalian eye primordia. We find that the overexpression of a dominant-negative form of GIPC1 (dnGIPC1), as well as the downregulation of endogenous GIPC1, is sufficient to inhibit the development of eye field cells from mESCs. GIPC1 interacts directly with IGFR and participates in Akt1 activation, and pharmacological inhibition of Akt1 phosphorylation mimics the dnGIPC1 phenotype. Our data, together with previous studies in Xenopus, support the hypothesis that the GIPC1-PI3K-Akt1 pathway plays a key role in eye field specification in vertebrates.

  15. An insect eye based image sensor with very large field of view

    NARCIS (Netherlands)

    Moens, E.; Meuret, Y.; Ottevaere, H.; Sarkar, M.; San Segundo Bello, D.; Merken, P.; Thienpont, H.

    2010-01-01

    In this paper we discuss the design of a novel miniaturized image sensor based on the working principle of insect facet eyes. The main goals are to design an imaging system which captures a large field of view (FOV) and to find a good trade-off between image resolution and sensitivity. To capture a

  16. Eyes in the sky: Interactions between AGB winds and the interstellar magnetic field

    CERN Document Server

    van Marle, A J; Decin, L

    2014-01-01

    We aim to examine the role of the interstellar magnetic field in shaping the extended morphologies of slow dusty winds of Asymptotic Giant-branch (AGB) stars in an effort to pin-point the origin of so-called eye shaped CSE of three carbon-rich AGB stars. In addition, we seek to understand if this pre-planetary nebula (PN) shaping can be responsible for asymmetries observed in PNe. Hydrodynamical simulations are used to study the effect of typical interstellar magnetic fields on the free-expanding spherical stellar winds as they sweep up the local interstellar medium (ISM). The simulations show that typical Galactic interstellar magnetic fields of 5 to 10 muG, are sufficient to alter the spherical expanding shells of AGB stars to appear as the characteristic eye shape revealed by far-infrared observations. The typical sizes of the simulated eyes are in accordance with the observed physical sizes. However, the eye shapes are of transient nature. Depending on the stellar and interstellar conditions they develop ...

  17. Watching eyes on potential litter can reduce littering: evidence from two field experiments.

    Science.gov (United States)

    Bateson, Melissa; Robinson, Rebecca; Abayomi-Cole, Tim; Greenlees, Josh; O'Connor, Abby; Nettle, Daniel

    2015-01-01

    Littering constitutes a major societal problem, and any simple intervention that reduces its prevalence would be widely beneficial. In previous research, we have found that displaying images of watching eyes in the environment makes people less likely to litter. Here, we investigate whether the watching eyes images can be transferred onto the potential items of litter themselves. In two field experiments on a university campus, we created an opportunity to litter by attaching leaflets that either did or did not feature an image of watching eyes to parked bicycles. In both experiments, the watching eyes leaflets were substantially less likely to be littered than control leaflets (odds ratios 0.22-0.32). We also found that people were less likely to litter when there other people in the immediate vicinity than when there were not (odds ratios 0.04-0.25) and, in one experiment but not the other, that eye leaflets only reduced littering when there no other people in the immediate vicinity. We suggest that designing cues of observation into packaging could be a simple but fruitful strategy for reducing littering.

  18. Watching eyes on potential litter can reduce littering: evidence from two field experiments

    Directory of Open Access Journals (Sweden)

    Melissa Bateson

    2015-12-01

    Full Text Available Littering constitutes a major societal problem, and any simple intervention that reduces its prevalence would be widely beneficial. In previous research, we have found that displaying images of watching eyes in the environment makes people less likely to litter. Here, we investigate whether the watching eyes images can be transferred onto the potential items of litter themselves. In two field experiments on a university campus, we created an opportunity to litter by attaching leaflets that either did or did not feature an image of watching eyes to parked bicycles. In both experiments, the watching eyes leaflets were substantially less likely to be littered than control leaflets (odds ratios 0.22–0.32. We also found that people were less likely to litter when there other people in the immediate vicinity than when there were not (odds ratios 0.04–0.25 and, in one experiment but not the other, that eye leaflets only reduced littering when there no other people in the immediate vicinity. We suggest that designing cues of observation into packaging could be a simple but fruitful strategy for reducing littering.

  19. Mimicking honeybee eyes with a 280{sup 0} field of view catadioptric imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Stuerzl, W; Boeddeker, N; Dittmar, L; Egelhaaf, M, E-mail: wolfgang.stuerzl@uni-bielefeld.d [Department of Neurobiology and Center of Excellence ' Cognitive Interaction Technology' , Bielefeld University (Germany)

    2010-09-15

    We present a small single camera imaging system that provides a continuous 280{sup 0} field of view (FOV) inspired by the large FOV of insect eyes. This is achieved by combining a curved reflective surface that is machined into acrylic glass with lenses covering the frontal field that otherwise would have been obstructed by the mirror. Based on the work of Seidl (1982 PhD Thesis Technische Hochschule Darmstadt), we describe an extension of the 'bee eye optics simulation' (BEOS) model by Giger (1996 PhD Thesis Australian National University) to the full FOV which enables us to remap camera images according to the spatial resolution of honeybee eyes. This model is also useful for simulating the visual input of a bee-like agent in a virtual environment. The imaging system in combination with our bee eye model can serve as a tool for assessing the visual world from a bee's perspective which is particularly helpful for experimental setups. It is also well suited for mobile robots, in particular on flying vehicles that need light-weight sensors.

  20. Comparison of Photopic Negative Response of Full-Field and Focal Electroretinograms in Detecting Glaucomatous Eyes

    Directory of Open Access Journals (Sweden)

    Shigeki Machida

    2011-01-01

    Full Text Available Purpose. To compare the photopic negative response (PhNR of the full-field electroretinogram (ERG to the PhNR of the focal ERGs in detecting glaucoma. Methods. One hundred and three eyes with glaucoma and 42 normal eyes were studied. Full-field ERGs were elicited by red stimuli on a blue background. The focal ERGs were elicited by a 15∘ white stimulus spot centered on the macula, the superotemporal or the inferotemporal areas of the macula. Results. In early glaucoma, the areas under the receiver operating characteristic curves (AUCs were significantly larger for the focal PhNR (0.863–0.924 than those for the full-field PhNR (0.666–0.748 (P<.05. The sensitivity was significantly higher for the focal PhNR than for the full-field PhNR in early (P<.01 and intermediate glaucoma (P<.05. In advanced glaucoma, there was no difference in the AUCs and sensitivities between the focal and full-field PhNRs. Conclusions. The focal ERG has the diagnostic ability with higher sensitivity in detecting early and intermediate glaucoma than the full-field ERG.

  1. Association between eye and hand dominance and hitting, fielding and pitching skill among players of the Southern Baseball League.

    Science.gov (United States)

    Classe, J G; Daum, K; Semes, L; Wisniewski, J; Rutstein, R; Alexander, L; Beisel, J; Mann, K; Nawakowski, R; Smith, M; Bartolucci, A

    1996-02-01

    The relationship between eye dominance and batting skill in baseball has been investigated, but conflicting results have been obtained. In addition, little attention has been given to the relationship, if any, between eye dominance and fielding and pitching skill. A vision screening of 215 professional baseball players in the Southern Baseball League was performed and the eye dominance of these players was determined by a sighting test. Handedness for batting, fielding, and pitching was determined by history. The screening revealed that 66 percent of players were right-eye dominant and that, of 92 players who met the criteria established to qualify for the league batting championship, 60 percent had matched dominance of eye and hand. When official league batting averages were obtained for these 92 players, it was found that there was no statistically significant difference between batters with matched dominance (.278 mean batting average). For the 149 fielders in the league, no statistically significant differences based on eye dominance were found for fielding average (.893 matched dominance, .864 crossed dominance); for the 89 pitchers, a similar result was obtained. Pitchers were also evaluated with respect to eye dominance and earned run average, but no significant difference was found (3.91 matched dominance, 4.03 crossed dominance). Results indicate that there is no association between eye dominance, and hitting, fielding, or pitching skill in baseball.

  2. Reverse design of a bull's eye structure based on the plasmonic far-field pattern.

    Science.gov (United States)

    Yamada, Akira; Terakawa, Mitsuhiro

    2013-09-09

    We present a novel concept on designing a bull's eye structure for a single-wavelength optical source. The plasmonic far-field around a subwavelength aperture on a thin gold film is calculated by finite-difference time-domain method. Based on the annular field intensity distribution on the film surface, we present a method for determining a fairly optimal first groove radius and a periodicity of the grooves that show enhanced transmission. By additionally fine-tuning groove width and groove depth, we have achieved a transmission factor of 9.74. Our novel method has high potential in applications such as silicon infrared sensors.

  3. Relationship Of FEF25-75, PEFR And SVC With Estrogen And Progesterone Level In Postmenopausal Women

    Directory of Open Access Journals (Sweden)

    Afroza Begum

    2011-12-01

    Full Text Available Background: Deterioration of lung function is common in women after menopause, which may be related to very low estrogen and progesterone level.Objective: To observe FEF25-75, PEFR and SVC (slow vital capacity values in apparently healthy postmenopausal women to find out their relationships with serum estrogen and progesterone.Methods: This study was carried out in the Department of Physiology in BSMMU, Dhaka in the year 2007. 30 healthy postmenopausal women aged 45 to 60 years and 30 healthy premenopausal women aged 20 to 30 years during their different phases of menstrual cycle were studied. Postmenopausal women were residents of Dhaka city and premenopausal subjects were medical students. FEF25-75, PEFR and SVC of all subjects were measured by a digital micro spirometer. Their estrogen and progesterone levels were estimated by Micro particle Enzyme Immunoassay (MEIA method. Data were analyzed by Pearson’s correlation coefficient test, one way ANOVA and unpaired‘t’ testResults: The mean percentage of predicted values of FEF25-75 and PEFR were lower in postmenopausal women compared to those of follicular and luteal phases of premenopausal women but it was not significant. Measured values of SVC was Significantly (p<.001 lower in postmenopausal women compared to those of follicular and luteal phases of premenopausal women. Again Mean serum estrogen and progesterone levels were significantly (p<.001 lower in post menopausal women compared to those of follicular and luteal phases of premenopausal women. In post menopausal women, FEF25-75 was positively, PEFR and SVC were negatively correlated with progesterone level. PEFR and SVC showed positive correlattion and FEF25-75 showed negative correlation with serum estrogen level. All these correlations were statistically non significant. In premenopausal women FEF25-75 and PEFR showed positive correlation and SVC showed negative correlation with serum progesterone level. The relationships were

  4. Structural and magnetic properties of FeF sub 2 (001)/ZnF sub 2 (001) and FeF sub 2 (110)/ZnF sub 2 (110) superlattices

    CERN Document Server

    Yamazaki, H

    2003-01-01

    Using the molecular beam epitaxy technique, fluoride superlattices of FeF sub 2 (001)/ZnF sub 2 (001) and FeF sub 2 (110)/ZnF sub 2 (110) were prepared on single-crystal substrates, Al sub 2 O sub 3 (101-bar 0) and MgO(100), respectively. In addition to structural characterization, dependence of the Neel temperature on the thickness of the FeF sub 2 (001) and (110) layers was investigated in detail. The observed periodic variations of the Neel temperature with a period of 1 atomic monolayer were discussed in terms of an interface-topographical frustration due to the competing exchange interactions of J sub 2 and J sub 3.

  5. Spatiotemporal multiplexing method for visual field of view extension in holographic displays with naked eye observation

    Science.gov (United States)

    Finke, G.; Kujawińska, M.; Kozacki, T.; Zaperty, W.

    2016-09-01

    In this paper we propose a method which allows to overcome the basic functional problems in holographic displays with naked eye observation caused by delivering too small images visible in narrow viewing angles. The solution is based on combining the spatiotemporal multiplexing method with a 4f optical system. It enables to increase an aperture of a holographic display and extend the angular visual field of view. The applicability of the modified display is evidenced by Wigner distribution analysis of holographic imaging with spatiotemporal multiplexing method and by the experiments performed at the display demonstrator.

  6. Novel and scalable solid-state synthesis of a nanocrystalline FeF3/C composite and its excellent electrochemical performance.

    Science.gov (United States)

    Lee, Jangwook; Kang, Byoungwoo

    2016-07-19

    A scalable solid-state reaction is presented to synthesize an FeF3 cathode material by using PTFE as a source of both fluorine and carbon. The method yields nanocrystalline FeF3/C showing excellent electrochemical performance even without any conducting additive. This method can be utilized for engineering MFs' properties and developing other fluorine compounds.

  7. Bright-Field Imaging and Optical Coherence Tomography of the Mouse Posterior Eye.

    Science.gov (United States)

    Krebs, Mark P; Xiao, Mei; Sheppard, Keith; Hicks, Wanda; Nishina, Patsy M

    2016-01-01

    Noninvasive live imaging has been used extensively for ocular phenotyping in mouse vision research. Bright-field imaging and optical coherence tomography (OCT) are two methods that are particularly useful for assessing the posterior mouse eye (fundus), including the retina, retinal pigment epithelium, and choroid, and are widely applied due to the commercial availability of sophisticated instruments and software. Here, we provide a guide to using these approaches with an emphasis on post-acquisition image processing using Fiji, a bundled version of the Java-based public domain software ImageJ. A bright-field fundus imaging protocol is described for acquisition of multi-frame videos, followed by image registration to reduce motion artifacts, averaging to reduce noise, shading correction to compensate for uneven illumination, filtering to improve image detail, and rotation to adjust orientation. An OCT imaging protocol is described for acquiring replicate volume scans, with subsequent registration and averaging to yield three-dimensional datasets that show reduced motion artifacts and enhanced detail. The Fiji algorithms used in these protocols are designed for batch processing and are freely available. The image acquisition and processing approaches described here may facilitate quantitative phenotyping of the mouse eye in drug discovery, mutagenesis screening, and the functional cataloging of mouse genes by individual laboratories and large-scale projects, such as the Knockout Mouse Phenotyping Project and International Mouse Phenotyping Consortium.

  8. Temporal dynamics of retinal and extraretinal signals in the FEFsem during smooth pursuit eye movements.

    Science.gov (United States)

    Bakst, Leah; Fleuriet, Jérome; Mustari, Michael J

    2017-05-01

    Neurons in the smooth eye movement subregion of the frontal eye field (FEFsem) are known to play an important role in voluntary smooth pursuit eye movements. Underlying this function are projections to parietal and prefrontal visual association areas and subcortical structures, all known to play vital but differing roles in the execution of smooth pursuit. Additionally, the FEFsem has been shown to carry a diverse array of signals (e.g., eye velocity, acceleration, gain control). We hypothesized that distinct subpopulations of FEFsem neurons subserve these diverse functions and projections, and that the relative weights of retinal and extraretinal signals could form the basis for categorization of units. To investigate this, we used a step-ramp tracking task with a target blink to determine the relative contributions of retinal and extraretinal signals in individual FEFsem neurons throughout pursuit. We found that the contributions of retinal and extraretinal signals to neuronal activity and behavior change throughout the time course of pursuit. A clustering algorithm revealed three distinct neuronal subpopulations: cluster 1 was defined by a higher sensitivity to eye velocity, acceleration, and retinal image motion; cluster 2 had greater activity during blinks; and cluster 3 had significantly greater eye position sensitivity. We also performed a comparison with a sample of medial superior temporal neurons to assess similarities and differences between the two areas. Our results indicate the utility of simple tests such as the target blink for parsing the complex and multifaceted roles of cortical areas in behavior.NEW & NOTEWORTHY The frontal eye field (FEF) is known to play a critical role in volitional smooth pursuit, carrying a variety of signals that are distributed throughout the brain. This study used a novel application of a target blink task during step ramp tracking to determine, in combination with a clustering algorithm, the relative contributions of

  9. Effects of search efficiency on surround suppression during visual selection in frontal eye field.

    Science.gov (United States)

    Schall, Jeffrey D; Sato, Takashi R; Thompson, Kirk G; Vaughn, Amanda A; Juan, Chi-Hung

    2004-06-01

    Previous research has shown that visually responsive neurons in the frontal eye field of macaque monkeys select the target for a saccade during efficient, pop-out visual search through suppression of the representation of the nontarget distractors. For a fraction of these neurons, the magnitude of this distractor suppression varied with the proximity of the target to the receptive field, exhibiting more suppression of the distractor representation when the target was nearby than when the target was distant. The purpose of this study was to determine whether the variation of distractor suppression related to target proximity varied with target-distractor feature similarity. The effect of target proximity on distractor suppression did not vary with target-distractor similarity and therefore may be an endogenous property of the selection process.

  10. Sequential activation of human oculomotor centers during planning of visually-guided eye movements: a combined fMRI-MEG study.

    Directory of Open Access Journals (Sweden)

    Carlo Sestieri

    2008-03-01

    Full Text Available We used magneto-encephalography (MEG to measure visually evoked activity in healthy volunteers performing saccadic eye movements to visual targets. The neuromagnetic activity was analyzed from regions of cortical activation identifi ed in separate functional magnetic resonance imaging (fMRI studies. The latency of visual responses signifi cantly increased from the Middle Temporal region (MT+ to the Intraparietal Sulcus (IPS to the Frontal Eye Field (FEF, and their amplitude was greater in the hemisphere contralateral to the visual target. Trial-to-trial variability of oculomotor reaction times correlated with visual response latency across cortical areas. These results support a feedforward recruitment of oculomotor cortical centers by visual information, and a model in which behavioral variability depends on variability at different neural stages of processing.

  11. Computation of temperature elevation in rabbit eye irradiated by 2.45-GHz microwaves with different field configurations.

    Science.gov (United States)

    Hirata, Akimasa; Watanabe, Soichi; Taki, Masao; Fujiwara, Osamu; Kojima, Masami; Sasaki, Kazuyuki

    2008-02-01

    This study calculated the temperature elevation in the rabbit eye caused by 2.45-GHz near-field exposure systems. First, we calculated specific absorption rate distributions in the eye for different antennas and then compared them with those observed in previous studies. Next, we re-examined the temperature elevation in the rabbit eye due to a horizontally-polarized dipole antenna with a C-shaped director, which was used in a previous study. For our computational results, we found that decisive factors of the SAR distribution in the rabbit eye were the polarization of the electromagnetic wave and antenna aperture. Next, we quantified the eye average specific absorption rate as 67 W kg(-1) for the dipole antenna with an input power density at the eye surface of 150 mW cm(-2), which was specified in the previous work as the minimum cataractogenic power density. The effect of administrating anesthesia on the temperature elevation was 30% or so in the above case. Additionally, the position where maximum temperature in the lens appears is discussed due to different 2.45-GHz microwave systems. That position was found to appear around the posterior of the lens regardless of the exposure condition, which indicates that the original temperature distribution in the eye was the dominant factor.

  12. Effect of the hypomagnetic field on the size of the eye pupil

    CERN Document Server

    Binhi, Vladimir N

    2013-01-01

    Previously, we reported that the hypomagnetic field obtained by the 100-fold deprivation of the geomagnetic field affected human cognitive processes as estimated in several computer tests. The exposure to the hypomagnetic field caused a statistically significant increase both in the task processing time and in the number of errors. The magnitude of this magnetic effect, averaged over 40 healthy subjects and more than 10^5 separate trials, was about 1.7%. In the present work, the results of a simultaneous study are described, in which the right eye of each subject was video recorded, while the subject performed the tasks. It has appeared that the pupil size grows in the hypomagnetic field. This effect has been calculated based on the treatment of a large data set of about 6.10^6 video frames. Averaged all over the frames, the magnetic effect on the pupil area was about 1.6%, with high statistical confidence. This is the first laboratory study in which the number of separate trials has been large enough to obta...

  13. Design, simulation and evaluation of uniform magnetic field systems for head-free eye movement recordings with scleral search coils.

    Science.gov (United States)

    Eibenberger, Karin; Eibenberger, Bernhard; Rucci, Michele

    2016-08-01

    The precise measurement of eye movements is important for investigating vision, oculomotor control and vestibular function. The magnetic scleral search coil technique is one of the most precise measurement techniques for recording eye movements with very high spatial (≈ 1 arcmin) and temporal (>kHz) resolution. The technique is based on measuring voltage induced in a search coil through a large magnetic field. This search coil is embedded in a contact lens worn by a human subject. The measured voltage is in direct relationship to the orientation of the eye in space. This requires a magnetic field with a high homogeneity in the center, since otherwise the field inhomogeneity would give the false impression of a rotation of the eye due to a translational movement of the head. To circumvent this problem, a bite bar typically restricts head movement to a minimum. However, the need often emerges to precisely record eye movements under natural viewing conditions. To this end, one needs a uniform magnetic field that is uniform over a large area. In this paper, we present the numerical and finite element simulations of the magnetic flux density of different coil geometries that could be used for search coil recordings. Based on the results, we built a 2.2 × 2.2 × 2.2 meter coil frame with a set of 3 × 4 coils to generate a 3D magnetic field and compared the measured flux density with our simulation results. In agreement with simulation results, the system yields a highly uniform field enabling high-resolution recordings of eye movements.

  14. Binocular neurons in parastriate cortex: interocular 'matching' of receptive field properties, eye dominance and strength of silent suppression.

    Directory of Open Access Journals (Sweden)

    Phillip A Romo

    Full Text Available Spike-responses of single binocular neurons were recorded from a distinct part of primary visual cortex, the parastriate cortex (cytoarchitectonic area 18 of anaesthetized and immobilized domestic cats. Functional identification of neurons was based on the ratios of phase-variant (F1 component to the mean firing rate (F0 of their spike-responses to optimized (orientation, direction, spatial and temporal frequencies and size sine-wave-luminance-modulated drifting grating patches presented separately via each eye. In over 95% of neurons, the interocular differences in the phase-sensitivities (differences in F1/F0 spike-response ratios were small (≤ 0.3 and in over 80% of neurons, the interocular differences in preferred orientations were ≤ 10°. The interocular correlations of the direction selectivity indices and optimal spatial frequencies, like those of the phase sensitivies and optimal orientations, were also strong (coefficients of correlation r ≥ 0.7005. By contrast, the interocular correlations of the optimal temporal frequencies, the diameters of summation areas of the excitatory responses and suppression indices were weak (coefficients of correlation r ≤ 0.4585. In cells with high eye dominance indices (HEDI cells, the mean magnitudes of suppressions evoked by stimulation of silent, extra-classical receptive fields via the non-dominant eyes, were significantly greater than those when the stimuli were presented via the dominant eyes. We argue that the well documented 'eye-origin specific' segregation of the lateral geniculate inputs underpinning distinct eye dominance columns in primary visual cortices of mammals with frontally positioned eyes (distinct eye dominance columns, combined with significant interocular differences in the strength of silent suppressive fields, putatively contribute to binocular stereoscopic vision.

  15. An Eye Movement Study on the Role of the Visual Field Defect in Pure Alexia

    Science.gov (United States)

    Bormann, Tobias; Wolfer, Sascha A.; Hachmann, Wibke; Lagrèze, Wolf A.; Konieczny, Lars

    2014-01-01

    Pure alexia is a severe impairment of word reading which is usually accompanied by a right-sided visual field defect. Patients with pure alexia exhibit better preserved writing and a considerable word length effect, claimed to result from a serial letter processing strategy. Two experiments compared the eye movements of four patients with pure alexia to controls with simulated visual field defects (sVFD) when reading single words. Besides differences in response times and differential effects of word length on word reading in both groups, fixation durations and the occurrence of a serial, letter-by-letter fixation strategy were investigated. The analyses revealed quantitative and qualitative differences between pure alexic patients and unimpaired individuals reading with sVFD. The patients with pure alexia read words slower and exhibited more fixations. The serial, letter-by-letter fixation strategy was observed only in the patients but not in the controls with sVFD. It is argued that the VFD does not cause pure alexic reading. PMID:24999811

  16. Wide field OCT based microangiography in living human eye (Conference Presentation)

    Science.gov (United States)

    Zhang, Qinqin; Chen, Chieh-Li; Chu, Zhongdi; Zhang, Anqi; An, Lin; Durbin, Mary; Sharma, Utkarsh; Rosenfeld, Philip J.; Wang, Ruikang K.

    2016-03-01

    To investigate the application of optical microangiography (OMAG) in living human eye. Patients with different macular diseases were recruited, including diabetic retinopathy (DR), geographic atrophy (GA), retinitis pigmentosa (RP), and venous occlusion, et al. Wide field OCT angiography images can be generated by montage scanning protocol based on the tracking system. OMAG algorithm based on complex differentiation was used to extract the blood flow and removed the bulk motion by 2D cross-correlation method. The 3D angiography was segmented into 3 layers in the retina and 2 layers in the choroid. The en-face maximum projection was used to obtain 2-dimensional angiograms of different layers coded with different colors. Flow and structure images were combined for cross-sectional view. En face OMAG images of different macular diseases showed a great agreement with FA. Meanwhile, OMAG gave more distinct vascular network visions that were less affected by hemorrhage and leakage. The MAs were observed in both superficial and middle retinal layers based on OMAG angiograms in different layers of DR patients. The contour line of FAZ was extracted as well, which can be quantitative the retinal diseases. For GA patient, the damage of RPE layer enhanced the penetration of light and enabled the acquisition of choriocapillaries and choroidal vessels. The wide field OMAG angiogram enabled the capability of capturing the entire geographic atrophy. OMAG provides depth-resolved information and detailed vascular images of DR and GA patients, providing a better visualization of vascular network compared to FA.

  17. Dishevelled mediates ephrinB1 signalling in the eye field through the planar cell polarity pathway.

    Science.gov (United States)

    Lee, Hyun-Shik; Bong, Yong-Sik; Moore, Kathryn B; Soria, Kathleen; Moody, Sally A; Daar, Ira O

    2006-01-01

    An important step in retinal development is the positioning of progenitors within the eye field where they receive the local environmental signals that will direct their ultimate fate. Recent evidence indicates that ephrinB1 functions in retinal progenitor movement, but the signalling pathway is unclear. We present evidence that ephrinB1 signals through its intracellular domain to control retinal progenitor movement into the eye field by interacting with Xenopus Dishevelled (Xdsh), and by using the planar cell polarity (PCP) pathway. Blocking Xdsh translation prevents retinal progeny from entering the eye field, similarly to the morpholino-mediated loss of ephrinB1 (ref. 2). Overexpression of Xdsh can rescue the phenotype induced by loss of ephrinB1, and this rescue (as well as a physical association between Xdsh and ephrinB1) is completely dependent on the DEP (Dishevelled, Egl-10, Pleckstrin) domain of Xdsh. Similar gain- and loss-of-function experiments suggest that Xdsh associates with ephrinB1 and mediates ephrinB1 signalling through downstream members of the PCP pathway during eye field formation.

  18. A fundamental study on carbon composites of FeF3.0.33H2O as open-framework cathode materials for calcium-ion batteries

    Science.gov (United States)

    Murata, Yoshiaki; Minami, Ryoji; Takada, Shoki; Aoyanagi, Kengo; Tojo, Tomohiro; Inada, Ryoji; Sakurai, Yoji

    2017-01-01

    Carbon composites of open-framework iron fluoride (FeF3.0.33H2O/C) was investigated as a new cathode material for calcium ion batteries for the first time. FeF3.0.33H2O/C delivers a relatively large capacity of ca. 110mAhg-1. Its reversible capacity was greatly improved over non-composite FeF3.0.33H2O. During the first discharge and discharge-charge, insertion/extraction of Ca2+ into/from FeF3.0.33H2O/C were confirmed by an ex-situ X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) analysis. From the ex-situ analysis results, it was confirmed that Ca2+ was inserted and extracted with redox of Fe.

  19. Experimental and theoretical investigation on the compression mechanism of FeF3 up to 62.0 GPa.

    Science.gov (United States)

    Zhu, Feng; Lai, Xiaojing; Wu, Xiang; Li, Yanchun; Qin, Shan

    2014-10-01

    VF3-type FeF3 is generally considered as a perovskite with a completely vacant A site. The high-pressure structural evolution of FeF3 has been studied by both X-ray diffraction and theoretical simulation up to 62.0 GPa. Experimental and theoretical results demonstrate that VF3-type FeF3 is stable up to 50 GPa. The structural evolution presents three features at different pressure ranges. At P GPa, the volume reduction is dominated by the FeF6 octahedral rotation, and a small octahedral strain develops upon compression, which represents an elongation of FeF6 octahedra along the c axis. Between 10 and 25 GPa, the volume reduction is mainly attributed to the Fe-F bond length decreasing, and the octahedral strain gradually disappears. Between 25 and 50 GPa, an octahedral elongation along the a axis quickly develops, resulting in a substantial structural distortion. Structural instability is predicted at P > 51 GPa on the basis of a soft mode occurring in phonon calculations. The pressure-volume relationship is described by a third-order Birch-Murnaghan equation-of-state with B0 = 14 (1) GPa, B0' = 17 (1) by experiment and B0 = 10.45 (1) GPa, B'10 = 12.13 (1) by calculation.

  20. Effect of Na3FeF6 catalyst on the hydrogen storage properties of MgH2.

    Science.gov (United States)

    Sulaiman, N N; Mustafa, N S; Ismail, M

    2016-04-28

    The effects of Na3FeF6 catalyst on the hydrogen storage properties of MgH2 have been studied for the first time. The results showed that for the MgH2 sample doped with 10 wt% Na3FeF6, the onset dehydrogenation temperature decreased to 255 °C, which was 100 °C and 162 °C lower than those of the as-milled and as-received MgH2 sample, respectively. The re/dehydrogenation kinetics were also significantly enhanced compared to the un-doped MgH2. The absorption kinetics showed that the as-milled MgH2 only absorbed 3.0 wt% of hydrogen at 320 °C in 2 min of rehydrogenation, but about 3.6 wt% of hydrogen was absorbed within the same period of time after 10 wt% Na3FeF6 was added to MgH2. The desorption kinetics showed that the MgH2 + 10 wt% Na3FeF6 sample could desorb about 3.8 wt% of hydrogen in 10 min at 320 °C. In contrast, the un-doped MgH2 sample desorbed only 0.2 wt% of hydrogen in the same period of time. The activation energy for the decomposition of the as-milled MgH2 was 167.0 kJ mol(-1), and this value decreased to 75.0 kJ mol(-1) after the addition of 10 wt% Na3FeF6 (a reduction by about 92.0 kJ mol(-1)). It is believed that the in situ formation of the active species of NaMgF3, NaF and Fe during the heating process could enhance the hydrogen storage properties of MgH2, due to the catalytic effects of these new species.

  1. Dry Eye

    Science.gov (United States)

    ... Eye > Facts About Dry Eye Facts About Dry Eye This information was developed by the National Eye ... the best person to answer specific questions. Dry Eye Defined What is dry eye? Dry eye occurs ...

  2. Eye Allergies

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Eye Allergies Sections What Are Eye Allergies? Eye Allergy Symptoms ... allergy diagnosis Eye allergy treatment What Are Eye Allergies? Written by: David Turbert Reviewed by: Brenda Pagan- ...

  3. Impact of Spatial Resolution on Wind Field Derived Estimates of Air Pressure Depression in the Hurricane Eye

    Directory of Open Access Journals (Sweden)

    Linwood Jones

    2010-03-01

    Full Text Available Measurements of the near surface horizontal wind field in a hurricane with spatial resolution of order 1–10 km are possible using airborne microwave radiometer imagers. An assessment is made of the information content of the measured winds as a function of the spatial resolution of the imager. An existing algorithm is used which estimates the maximum surface air pressure depression in the hurricane eye from the maximum wind speed. High resolution numerical model wind fields from Hurricane Frances 2004 are convolved with various HIRAD antenna spatial filters to observe the impact of the antenna design on the central pressure depression in the eye that can be deduced from it.

  4. Biodistribution and dosimetry of 18F-EF5 in cancer patients with preliminary comparison of 18F-EF5 uptake versus EF5 binding in human glioblastoma

    Science.gov (United States)

    Koch, Cameron J.; Scheuermann, Joshua S.; Divgi, Chaitanya; Judy, Kevin D.; Kachur, Alexander V.; Freifelder, Richard; Reddin, Janet S.; Karp, Joel; Stubbs, James B.; Hahn, Stephen M.; Driesbaugh, Jason; Smith, Deborah; Prendergast, Susan; Evans, Sydney M.

    2010-01-01

    Purpose The primary purpose of this study was to assess the biodistribution and radiation dose resulting from administration of 18F-EF5, a lipophilic 2-nitroimidazole hypoxia marker in ten cancer patients. For three of these patients (with glioblastoma) unlabeled EF5 was additionally administered to allow the comparative assessment of 18F-EF5 tumor uptake with EF5 binding, the latter measured in tumor biopsies by fluorescent anti-EF5 monoclonal antibodies. Methods 18F-EF5 was synthesized by electrophilic addition of 18F2 gas, made by deuteron bombardment of a neon/fluorine mixture in a high-pressure gas target, to an allyl precursor in trifluoroacetic acid at 0° then purified and administered by intravenous bolus. Three whole-body images were collected for each of ten patients using an Allegro (Philips) scanner. Gamma counts were determined in blood, drawn during each image, and urine, pooled as a single sample. PET images were analyzed to determine radiotracer uptake in several tissues and the resulting radiation dose calculated using OLINDA software and standard phantom. For three patients, 21 mg/kg unlabeled EF5 was administered after the PET scans, and tissue samples obtained the next day at surgery to determine EF5 binding using immunohistochemistry techniques (IHC). Results EF5 distributes evenly throughout soft tissue within minutes of injection. Its concentration in blood over the typical time frame of the study (~3.5 h) was nearly constant, consistent with a previously determined EF5 plasma half-life of ~13 h. Elimination was primarily via urine and bile. Radiation exposure from labeled EF5 is similar to other 18F-labeled imaging agents (e.g., FDG and FMISO). In a de novo glioblastoma multiforme patient, focal uptake of 18F-EF5 was confirmed by IHC. Conclusion These results confirm predictions of biodistribution and safety based on EF5's characteristics (high biological stability, high lipophilicity). EF5 is a novel hypoxia marker with unique

  5. Processing emotion from the eyes: a divided visual field and ERP study.

    Science.gov (United States)

    Beaton, Alan A; Fouquet, Nathalie C; Maycock, Nicola C; Platt, Eleanor; Payne, Laura S; Derrett, Abigail

    2012-01-01

    The right cerebral hemisphere is preferentially involved in recognising at least some facial expressions of emotion. We investigated whether there is a laterality effect in judging emotions from the eyes. In one task a pair of emotionally expressive eyes presented in central vision had to be physically matched to a subsequently presented set of eyes in one or other visual hemifield (eyes condition). In the second task a word was presented centrally followed by a set of eyes to left or right hemifield and the participant had to decide whether the word correctly described the emotion portrayed by the laterally presented set of eyes (word condition). Participants were a group of undergraduate students and a group of older volunteers (> 50). There was no visual hemifield difference in accuracy or raw response times in either task for either group, but log-transformed times showed an overall left hemifield advantage. Contrary to the right hemisphere ageing hypothesis, older participants showed no evidence of a relative right hemisphere decline in performance on the tasks. In the younger group mean peak amplitude of the N170 component of the EEG at lateral posterior electrode sites was significantly greater over the right hemisphere (T6/PO2) than the left (T5/PO1) in both the perceptual recognition task and the emotional judgement task. It was significantly greater for the task of judging emotion than in the eyes-matching task. In future it would be useful to combine electrophysiological techniques with lateralised visual input in studying lateralisation of emotion with older as well as younger participants.

  6. Association of Myopic Deformation of Optic Disc with Visual Field Progression in Paired Eyes with Open-Angle Glaucoma

    Science.gov (United States)

    Hangai, Masanori; Ishikawa, Makoto; Yoshitomi, Takeshi

    2017-01-01

    Purpose The influence of myopia on glaucoma progression remains unknown, possibly because of the multifactorial nature of glaucoma and difficulty in assessing a solo contribution of myopia. The purpose of this study is to investigate the association of myopia with visual field (VF) progression in glaucoma using a paired-eye design to minimize the influence of confounding systemic factors that are diverse among individuals. Methods This retrospective study evaluated 144 eyes of 72 subjects with open-angle glaucoma, with similar intra-ocular pressure between paired eyes, spherical equivalent (SE) ≤ -2 diopter (D), and axial length ≥ 24 mm. Paired eyes with faster and slower VF progression were grouped separately, according to the global VF progression rate assessed by automated pointwise linear regression analysis. The SE, axial length, tilt ratio and torsion angle of optic discs, Bruch’s membrane (BM) opening area, and gamma zone parapapillary atrophy (PPA) width were compared between the two groups. Factors associated with faster VF progression were determined by logistic regression analysis. Results The mean follow-up duration was 8.9 ± 4.4 years. The mean value of SE and axial length were -6.31 ± 1.88 D and 26.05 ± 1.12 mm, respectively. The mean global visual field progression rate was -0.32 ± 0.38 dB/y. Tilt ratio, BM opening area, and gamma zone PPA width were significantly greater in the eyes with faster VF progression than those with slower progression. In multivariate analysis, these factors were significantly associated with faster VF progression (all P < 0.05), while SE and axial length were not associated with it. Conclusion In myopic glaucoma subjects, tilt of the optic disc and temporal shifting and enlargement of the BM opening were associated with faster rate of VF progression between paired eyes. This suggests that myopia influences VF progression in glaucomatous eyes via optic disc deformations rather than via refractive error itself

  7. Molecular beam epitaxy growth of SmFeAs(O,F) films with Tc = 55 K using the new fluorine source FeF3

    Science.gov (United States)

    Sakoda, Masahito; Ishii, Akihiro; Takinaka, Kenji; Naito, Michio

    2017-07-01

    REFeAs(O,F) (RE: rare-earth element) has the highest-Tc (˜58 K) among the iron-based superconductors, but a thin-film growth of REFeAs(O,F) is difficult. This is because it is not only a complex compound consisting of five elements but also requires doping of highly reactive fluorine to achieve superconductivity. We have reported in our previous article that fluorine can be supplied to a film by subliming solid-state fluorides such as FeF2 or SmF3. In this article, we report on the growth of SmFeAs(O,F) using FeF3 as an alternative fluorine source. FeF3 is solid at ambient temperatures and decomposes at temperatures as low as 100-200 °C, and releases fluorine-containing gas during the thermal decomposition. With this alternative fluorine source, we have grown SmFeAs(O,F) films with Tc as high as 55 K. This achievement demonstrates that FeF3 has potential as a fluorine source that can be employed ubiquitously for a thin-film growth of any fluorine containing compounds. One problem specific to FeF3 is that the compound is highly hydroscopic and contains a substantial amount of water even in its anhydrous form. In this article, we describe how to overcome this specific problem.

  8. Right Visual Field Advantage in Parafoveal Processing: Evidence from Eye-Fixation-Related Potentials

    Science.gov (United States)

    Simola, Jaana; Holmqvist, Kenneth; Lindgren, Magnus

    2009-01-01

    Readers acquire information outside the current eye fixation. Previous research indicates that having only the fixated word available slows reading, but when the next word is visible, reading is almost as fast as when the whole line is seen. Parafoveal-on-foveal effects are interpreted to reflect that the characteristics of a parafoveal word can…

  9. The effects of metamaterial on electromagnetic fields absorption characteristics of human eye tissues.

    Science.gov (United States)

    Gasmelseed, Akram; Yunus, Jasmy

    2014-01-01

    The interaction of a dipole antenna with a human eye model in the presence of a metamaterial is investigated in this paper. The finite difference time domain (FDTD) method with convolutional perfectly matched layer (CPML) formulation have been used. A three-dimensional anatomical model of the human eye with resolution of 1.25 mm × 1.25 mm × 1.25 mm was used in this study. The dipole antenna was driven by modulated Gaussian pulse and the numerical study is performed with dipole operating at 900 MHz. The analysis has been done by varying the size and value of electric permittivity of the metamaterial. By normalizing the peak SAR (1 g and 10 g) to 1 W for all examined cases, we observed how the SAR values are not affected by the different permittivity values with the size of the metamaterial kept fixed.

  10. FeF(3) catalyzed cascade C-C and C-N bond formation: synthesis of differentially substituted triheterocyclic benzothiazole functionalities under solvent-free condition.

    Science.gov (United States)

    Atar, Amol B; Jeong, Yeon Tae

    2014-05-01

    A series of diverse polyfunctionalized triheterocyclic benzothiazoles were easily prepared in excellent yields via the Biginelli reaction of 2-aminobenzothiazole with substituted benzaldehydes and α-methylene ketones using FeF(3) as an expeditious catalyst under solvent-free conditions. The protocol provides a practical and straightforward approach toward highly functionalized triheterocyclic benzothiazole derivatives in excellent yields. The reaction was conveniently promoted by FeF(3) and the catalyst could be recovered easily after the reaction and reused without any loss of its catalytic activity. The advantageous features of this methodology are high atom economy, operational simplicity, shorter reaction time, convergence, and facile automation.

  11. Eye redness

    Science.gov (United States)

    Bloodshot eyes; Red eyes; Scleral injection; Conjunctival injection ... There are many causes of a red eye or eyes. Some are medical emergencies. Others are a cause for concern, but not an emergency. Many are nothing to worry about. Eye ...

  12. Noninvasive imaging of tumor hypoxia in rats using the 2-nitroimidazole {sup 18}F-EF5

    Energy Technology Data Exchange (ETDEWEB)

    Ziemer, L.S. [University of Pennsylvania School of Veterinary Medicine, Section of Radiology, 3850 Spruce Street, Philadelphia, PA 19104 (United States); Evans, S.M.; Kachur, A.V.; Shuman, A.L.; Cardi, C.A.; Jenkins, W.T.; Karp, J.S.; Alavi, A.; Koch, C.J. [School of Medicine, University of Pennsylvania, Philadelphia (United States); Dolbier Jr., W.R. [Department of Chemistry, University of Florida, Gainesville, Florida (United States)

    2003-02-01

    Tumor hypoxia is an important prognostic indicator for cancer therapy outcome. EF5 2-(2-nitro-1[H]-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide has been employed to measure tumor hypoxia in animals and humans using immunohistochemical methods. EF5 is a lipophilic molecule designed to have a very uniform biodistribution, a feature of obvious benefit for use in PET imaging. The present study represents the first demonstration of noninvasive PET imaging of rat tumors using fluorine-18 labeled EF5. Because of the small tumor size, partial volume effects may result in underestimation of concentration of the compound. Therefore, validation of the PET data was performed by gamma counting of the imaged tissue. The tumor models studied were the Morris 7777 (Q7) hepatoma (n=5) and the 9L glioma (n=2) grown subcutaneously in rats. Our previous studies have demonstrated that early passage 9L tumors are not severely hypoxic and that Q7 tumors are characterized by heterogeneous regions of tumor hypoxia (i.e., Q7 tumors are usually more hypoxic than early passage 9L tumors). The seven rats were imaged in the HEAD Penn-PET scanner at various time points after administration of 50-100 {mu}Ci {sup 18}F-EF5 in 30 mg/kg carrier nonradioactive EF5. The carrier was used to ensure drug biodistribution comparable to prior studies using immunohistochemical methods. {sup 18}F-EF5 was excreted primarily via the urinary system. Images obtained 10 min following drug administration demonstrated that the EF5 distributed evenly to all organ systems, including brain. Later images showed increased uptake in most Q7 tumors compared with muscle. Liver uptake remained relatively constant over the same time periods. Tumor to muscle ratios ranged from 0.82 to 1.73 (based on PET images at 120 min post injection) and 1.47 to 2.95 (based on gamma counts at 180 min post injection). Tumors were easily visible by 60 min post injection when the final tumor to muscle ratios (based on gamma counts

  13. Truly simultaneous SS-OCT of the anterior and posterior human eye with full anterior chamber and 50° retinal field of views (Conference Presentation)

    Science.gov (United States)

    McNabb, Ryan P.; Viehland, Christian; Keller, Brenton; Vann, Robin R.; Izatt, Joseph A.; Kuo, Anthony N.

    2017-02-01

    Optical coherence tomography (OCT) has revolutionized clinical observation of the eye and is an indispensable part of the modern ophthalmic practice. Unlike many other ophthalmic imaging techniques, OCT provides three-dimensional information about the imaged eye. However, conventional clinical OCT systems image only the anterior or the posterior eye during a single acquisition. Newer OCT systems have begun to image both during the same acquisition but with compromises such as limited field of view in the posterior eye or requiring rapid switching between the anterior and posterior eye during the scan. We describe here the development and demonstration of an OCT system with truly simultaneous imaging of both the anterior and posterior eye capable of imaging the full anterior chamber width and 50° on the retina (macula, optic nerve, and arcades). The whole eye OCT system was developed using custom optics and optomechanics. Polarization was utilized to separate the imaging channels. We utilized a 200kHz swept-source laser (Axsun Technologies) centered at 1040±50nm of bandwidth. The clock signal generated by the laser was interpolated 4x to generate 5504 samples per laser sweep. With the whole eye OCT system, we simultaneously acquired anterior and posterior segments with repeated B-scans as well as three-dimensional volumes from seven healthy volunteers (other than refractive error). On three of these volunteers, whole eye OCT and partial coherence interferometry (LenStar PCI, Haag-Streit) were used to measure axial eye length. We measured a mean repeatability of ±47µm with whole eye OCT and a mean difference from PCI of -68µm.

  14. Xenopus mutant reveals necessity of rax for specifying the eye field which otherwise forms tissue with telencephalic and diencephalic character.

    Science.gov (United States)

    Fish, Margaret B; Nakayama, Takuya; Fisher, Marilyn; Hirsch, Nicolas; Cox, Amanda; Reeder, Rollin; Carruthers, Samantha; Hall, Amanda; Stemple, Derek L; Grainger, Robert M

    2014-11-15

    The retinal anterior homeobox (rax) gene encodes a transcription factor necessary for vertebrate eye development. rax transcription is initiated at the end of gastrulation in Xenopus, and is a key part of the regulatory network specifying anterior neural plate and retina. We describe here a Xenopus tropicalis rax mutant, the first mutant analyzed in detail from a reverse genetic screen. As in other vertebrates, this nonsense mutation results in eyeless animals, and is lethal peri-metamorphosis. Tissue normally fated to form retina in these mutants instead forms tissue with characteristics of diencephalon and telencephalon. This implies that a key role of rax, in addition to defining the eye field, is in preventing alternative forebrain identities. Our data highlight that brain and retina regions are not determined by the mid-gastrula stage but are by the neural plate stage. An RNA-Seq analysis and in situ hybridization assays for early gene expression in the mutant revealed that several key eye field transcription factors (e.g. pax6, lhx2 and six6) are not dependent on rax activity through neurulation. However, these analyses identified other genes either up- or down-regulated in mutant presumptive retinal tissue. Two neural patterning genes of particular interest that appear up-regulated in the rax mutant RNA-seq analysis are hesx1 and fezf2. These genes were not previously known to be regulated by rax. The normal function of rax is to partially repress their expression by an indirect mechanism in the presumptive retina region in wildtype embryos, thus accounting for the apparent up-regulation in the rax mutant. Knock-down experiments using antisense morpholino oligonucleotides directed against hesx1 and fezf2 show that failure to repress these two genes contributes to transformation of presumptive retinal tissue into non-retinal forebrain identities in the rax mutant.

  15. A field test of Web-based screening for dry eye disease to enhance awareness of eye problems among general Internet users: a latent strategy to promote health

    National Research Council Canada - National Science Library

    Kawashima, Motoko; Uchino, Miki; Kawazoe, Takashi; Kamiyashiki, Masaaki; Sano, Kokoro; Tsubota, Kazuo

    2013-01-01

    .... The purpose of this preliminary study was to test a Web-based self-screening questionnaire for drawing attention to dry eye disease among general Internet users and identifying those with a higher...

  16. Ab initio study of the diatomic fluorides FeF, CoF, NiF, and CuF.

    Science.gov (United States)

    Koukounas, Constantine; Mavridis, Aristides

    2008-11-06

    The late-3d transition-metal diatomic fluorides MF = FeF, CoF, NiF, and CuF have been studied using variational multireference (MRCI) and coupled-cluster [RCCSD(T)] methods, combined with large to very large basis sets. We examined a total of 35 (2S+1)|Lambda| states, constructing as well 29 full potential energy curves through the MRCI method. All examined states are ionic, diabatically correlating to M(+)+F(-)((1)S). Notwithstanding the "eccentric" character of the 3d transition metals and the difficulties to accurately be described with all-electron ab initio methods, our results are, in general, in very good agreement with available experimental numbers.

  17. Neuroanatomical circuitry associated with exploratory eye movement in schizophrenia: a voxel-based morphometric study.

    Directory of Open Access Journals (Sweden)

    Linlin Qiu

    Full Text Available Schizophrenic patients present abnormalities in a variety of eye movement tasks. Exploratory eye movement (EEM dysfunction appears to be particularly specific to schizophrenia. However, the underlying mechanisms of EEM dysfunction in schizophrenia are not clearly understood. To assess the potential neuroanatomical substrates of EEM, we recorded EEM performance and conducted a voxel-based morphometric analysis of gray matter in 33 schizophrenic patients and 29 well matched healthy controls. In schizophrenic patients, decreased responsive search score (RSS and widespread gray matter density (GMD reductions were observed. Moreover, the RSS was positively correlated with GMD in distributed brain regions in schizophrenic patients. Furthermore, in schizophrenic patients, some brain regions with neuroanatomical deficits overlapped with some ones associated with RSS. These brain regions constituted an occipito-tempro-frontal circuitry involved in visual information processing and eye movement control, including the left calcarine cortex [Brodmann area (BA 17], the left cuneus (BA 18, the left superior occipital cortex (BA 18/19, the left superior frontal gyrus (BA 6, the left cerebellum, the right lingual cortex (BA 17/18, the right middle occipital cortex (BA19, the right inferior temporal cortex (BA 37, the right dorsolateral prefrontal cortex (BA 46 and bilateral precentral gyri (BA 6 extending to the frontal eye fields (FEF, BA 8. To our knowledge, we firstly reported empirical evidence that gray matter loss in the occipito-tempro-frontal neuroanatomical circuitry of visual processing system was associated with EEM performance in schizophrenia, which may be helpful for the future effort to reveal the underlying neural mechanisms for EEM disturbances in schizophrenia.

  18. Effect of the hypomagnetic field on the size of the eye pupil

    OpenAIRE

    Binhi, Vladimir N.; Sarimov, Ruslan M.

    2013-01-01

    Previously, we reported that the hypomagnetic field obtained by the 100-fold deprivation of the geomagnetic field affected human cognitive processes as estimated in several computer tests. The exposure to the hypomagnetic field caused a statistically significant increase both in the task processing time and in the number of errors. The magnitude of this magnetic effect, averaged over 40 healthy subjects and more than 10^5 separate trials, was about 1.7%. In the present work, the results of a ...

  19. For Whose Eyes Only? The Gatekeeping of Sexual Images in the Field of Teen Sexuality

    Science.gov (United States)

    Chittenden, Tara

    2010-01-01

    This article examines the ways in which gatekeepers shape the field of teen sexuality by controlling access to sexual images. I question who decides whether an image is "appropriate" for young adults and how such judgements shape the wider cultural field. The ways in which gatekeepers have attempted to shield teens from certain sexual images…

  20. For Whose Eyes Only? The Gatekeeping of Sexual Images in the Field of Teen Sexuality

    Science.gov (United States)

    Chittenden, Tara

    2010-01-01

    This article examines the ways in which gatekeepers shape the field of teen sexuality by controlling access to sexual images. I question who decides whether an image is "appropriate" for young adults and how such judgements shape the wider cultural field. The ways in which gatekeepers have attempted to shield teens from certain sexual images…

  1. Healthy Eyes

    Science.gov (United States)

    ... los Ojos Cómo hablarle a su oculista Healthy Eyes Having a comprehensive dilated eye exam is one ... or contact lenses. What is a comprehensive dilated eye exam? A comprehensive dilated eye exam is a ...

  2. Do images of 'watching eyes' induce behaviour that is more pro-social or more normative? A field experiment on littering.

    Science.gov (United States)

    Bateson, Melissa; Callow, Luke; Holmes, Jessica R; Redmond Roche, Maximilian L; Nettle, Daniel

    2013-01-01

    Displaying images of eyes causes people to behave more pro-socially in a variety of contexts. However, it is unclear whether eyes work by making people universally more pro-social, or by making them more likely to conform to local norms. If the latter, images of eyes could sometimes make people less pro-social if pro-social behaviour is not the local norm. To separate these hypotheses we conducted a field experiment in which we explored whether manipulating a local descriptive norm altered the eyes effect. We recorded litter dropping decisions on a university campus in a 2 x 2 design, comparing situations with and without litter already on the ground (a manipulation of the local descriptive norm) and with and without large signs displaying images of watching eyes. We additionally recorded the number of potential human observers in the vicinity at the time of each littering decision. We observed a norm effect: the presence of litter on the ground increased littering, replicating previous findings. We also found that images of watching eyes reduced littering, although contrary to previous findings this was only when there were larger numbers of people around. With regard to our central aim, we found no evidence that litter on the ground interacted non-additively with images of eyes to induce increased littering behaviour. Our data therefore support the hypothesis that images of eyes induce more pro-social behaviour, independent of local norms. This finding has positive implications for the application of eye images in combating anti-social behaviour.

  3. Do images of 'watching eyes' induce behaviour that is more pro-social or more normative? A field experiment on littering.

    Directory of Open Access Journals (Sweden)

    Melissa Bateson

    Full Text Available Displaying images of eyes causes people to behave more pro-socially in a variety of contexts. However, it is unclear whether eyes work by making people universally more pro-social, or by making them more likely to conform to local norms. If the latter, images of eyes could sometimes make people less pro-social if pro-social behaviour is not the local norm. To separate these hypotheses we conducted a field experiment in which we explored whether manipulating a local descriptive norm altered the eyes effect. We recorded litter dropping decisions on a university campus in a 2 x 2 design, comparing situations with and without litter already on the ground (a manipulation of the local descriptive norm and with and without large signs displaying images of watching eyes. We additionally recorded the number of potential human observers in the vicinity at the time of each littering decision. We observed a norm effect: the presence of litter on the ground increased littering, replicating previous findings. We also found that images of watching eyes reduced littering, although contrary to previous findings this was only when there were larger numbers of people around. With regard to our central aim, we found no evidence that litter on the ground interacted non-additively with images of eyes to induce increased littering behaviour. Our data therefore support the hypothesis that images of eyes induce more pro-social behaviour, independent of local norms. This finding has positive implications for the application of eye images in combating anti-social behaviour.

  4. Evaluating Experience-Based Geologic Field Instruction: Lessons Learned from A Large-Scale Eye-Tracking Experiment

    Science.gov (United States)

    Tarduno, J. A.; Walders, K.; Bono, R. K.; Pelz, J.; Jacobs, R.

    2015-12-01

    A course centered on experience-based learning in field geology has been offered ten times at the University of Rochester. The centerpiece of the course is a 10-day field excursion to California featuring a broad cross-section of the geology of the state, from the San Andreas Fault to Death Valley. Here we describe results from a large-scale eye-tracking experiment aimed at understanding how experts and novices acquire visual geologic information. One ultimate goal of the project is to determine whether expert gaze patterns can be quantified to improve the instruction of beginning geology students. Another goal is to determine if aspects of the field experience can be transferred to the classroom/laboratory. Accordingly, ultra-high resolution segmented panoramic images have been collected at key sites visited during the field excursion. We have found that strict controls are needed in the field to obtain meaningful data; this often involves behavior atypical of geologists (e.g. limiting the field of view prior to data collection and placing time limits on scene viewing). Nevertheless some general conclusions can be made from a select data set. After an initial quick search, experts tend to exhibit scanning behavior that appears to support hypothesis testing. Novice fixations appear to define a scattered search pattern and/or one distracted by geologic noise in a scene. Noise sources include modern erosion features and vegetation. One way to quantify noise is through the use of saliency maps. With the caveat that our expert data set is small, our preliminary analysis suggests that experts tend to exhibit top-down behavior (indicating hypothesis driven responses) whereas novices show bottom-up gaze patterns, influenced by more salient features in a scene. We will present examples and discuss how these observations might be used to improve instruction.

  5. Specification of embryonic stem cell-derived tissues into eye fields by Wnt signaling using rostral diencephalic tissue-inducing culture.

    Science.gov (United States)

    Sakakura, Eriko; Eiraku, Mototsugu; Takata, Nozomu

    2016-08-01

    The eyes are subdivided from the rostral diencephalon in early development. How the neuroectoderm regulates this subdivision, however, is largely unknown. Taking advantage of embryonic stem cell (ESC) culture using a Rax reporter line to monitor rostral diencephalon formation, we found that ESC-derived tissues at day 7 grown in Glasgow Minimum Expression Media (GMEM) containing knockout serum replacement (KSR) exhibited higher levels of expression of axin2, a Wnt target gene, than those grown in chemically defined medium (CDM). Surprisingly, Wnt agonist facilitated eye field-like tissue specification in CDM. In contrast, the addition of Wnt antagonist diminished eye field tissue formation in GMEM+KSR. Furthermore, the morphological formation of the eye tissue anlage, including the optic vesicle, was accompanied by Wnt signaling activation. Additionally, using CDM culture, we developed an efficient method for generating Rax+/Chx10+ retinal progenitors, which could become fully stratified retina. Here we provide a new avenue for exploring the mechanisms of eye field specification in vitro.

  6. Developments in the field of allergy in 2010 through the eyes of Clinical and Experimental Allergy

    DEFF Research Database (Denmark)

    Katelaris, C H; Linneberg, A; Magnan, A

    2011-01-01

    In 2010 over 200 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, letters, book reviews and of course at the heart of the journal, papers containing original data which have moved the field of allergy forward on a number of fronts. For ...

  7. Face Fields and Microperimetry for Estimating the Location of Fixation in Eyes with Macular Disease

    Science.gov (United States)

    Sunness, Janet S.

    2008-01-01

    Face field evaluation provides insights into the presence and location of the preferred retinal locus, as validated by comparisons with findings from microperimetry. This technique requires no special equipment and can be used in a clinic or at a person's home by clinicians and low vision rehabilitation specialists. (Contains 2 figures and 2…

  8. Fe-F3C İKİLİ DENGE DİYAGRAMININ BİLGİSAYARDA MODELLENMESİ

    Directory of Open Access Journals (Sweden)

    RAMAZAN YILMAZ

    2002-06-01

    Full Text Available Bu makalede, demir-sementit (Fe-F3C ikili denge diyagraınını, üzerindeki faz oranlarını, mikroyapısını ve aynı zamanda kristal kafeslerini göstere bilen bir bilgisayar modellernesi yapıldı. Bu belirti len paraınetreler hakkındaki teorik bilgiler ve mikroyapı fotoğrafları modelierne programı içerisine yüklendi. Bu modelierne Delphi bilgisayar yazılım programı kullanılarak yapıldı. Programın işleyişi başarı ile gerçekleştirildi. Program yardımıyla, Teknik ve Endüstri Meslek Liselerinde, Teknik Eği tim ve Mühendislik Fakültelerinin Malzeme Bilimi ders içeriği kapsamı doğrultusunda, eğitim ve öğretim de başarı ile uygulanabileceği umut edilmektedir.

  9. Determination of tumour hypoxia with the PET tracer [{sup 18}F]EF3: improvement of the tumour-to-background ratio in a mouse tumour model

    Energy Technology Data Exchange (ETDEWEB)

    Christian, Nicolas; Bol, Anne; Bast, Marc de; Labar, Daniel; Lee, John; Mahy, Pierre; Gregoire, Vincent [Universite Catholique de Louvain, Center for Molecular Imaging and Experimental Radiotherapy, Brussels (Belgium)

    2007-09-15

    The 2-(2-nitroimidazol-1-yl)-N-(3,3,3-trifluoropropyl)acetamide (EF3) is a 2-nitroimidazole derivative which undergoes bioreductive activation under hypoxic conditions. Using the PET tracer [{sup 18}F]EF3 in mice, tumour-to-muscle ratios ranging from 1.3 to 3.5 were observed. This study investigated the impact of various interventions aimed at increasing [{sup 18}F]EF3 elimination, thus potentially increasing the tumour-to-noise ratio in mice, by increasing the renal filtration rate (spironolactone, furosemide), decreasing tubular re-absorption (metronidazole, ornidazole, amino acid solution) or stimulating gastro-intestinal elimination (phenobarbital). C3H mice were injected i.v. with an average of 12.95 MBq of [{sup 18}F]EF3. Drugs were injected i.v. 15 min before the tracer or daily 4 days prior to the experiment (phenobarbital). Anaesthetised mice were imaged from 30 to 300 min with a dedicated animal PET (Mosaic, Philips). Regions of interest were delineated around the tumour, bladder, heart, liver and leg muscle. Radioactivity was expressed as a percentage of injected activity per gram of tissue. Ornidazole decreased the urinary excretion and increased the liver uptake of [{sup 18}F]EF3, but without causing any changes in the other organs. Phenobarbital significantly increased the liver concentration and decreased radioactivity in blood and muscle without affecting the tracer uptake in tumour. Consequently, a small but non-significant increase in tumour-to-noise ratio was observed. Although some effects were observed with other drugs, they did not modify the tumour-to-noise ratio. Only phenobarbital induced a trend toward an increased tumour-to-noise ratio that could possibly be tested in the clinical situation. (orig.)

  10. Hyper Open-Shell States: The Lowest Excited Spin States of O Atom, Fe(2+) Ion, and FeF2.

    Science.gov (United States)

    Varga, Zoltan; Verma, Pragya; Truhlar, Donald G

    2017-09-13

    Excited spin states are important for reactivity, catalysis, and magnetic applications. This work examines the relative energies of the spin states of O atom, Fe(2+) ion, and FeF2 and characterizes their excited spin states. Both single-configuration and multireference methods are used to establish the character of the lowest singlet excited state of all three systems and the lowest triplet excited state of Fe(2+) and FeF2. We find that the conventional representation of the orbital occupancies is incorrect in that the states have more unpaired electrons than the minimum number required by their total electron spin quantum number. In particular, we find that, for a given spin state, an electronic configuration with more than 2S unpaired electrons is more stable than the configuration with 2S unpaired electrons (where S is the spin of the system). For instance, triplet FeF2 with four unpaired electrons is lower in energy than triplet FeF2 with two unpaired electrons. Such highly open-shell configurations are labeled as hyper open-shell electronic configurations in this work and are compared to ordinary open-shell or closed-shell electronic configurations. The hyper open-shell states considered in this work are especially interesting because, unlike typical biradicals and polyradicals, the unpaired electrons are all on the same center. This work shows that the conventional perspective on spin-state energetics that usually assumes ordinary open shells for single-centered radicals needs modification to take into account, whenever possible, hyper open-shell configurations as well.

  11. Magnetic eye tracking in mice.

    Science.gov (United States)

    Payne, Hannah L; Raymond, Jennifer L

    2017-09-05

    Eye movements provide insights about a wide range of brain functions, from sensorimotor integration to cognition; hence, the measurement of eye movements is an important tool in neuroscience research. We describe a method, based on magnetic sensing, for measuring eye movements in head-fixed and freely moving mice. A small magnet was surgically implanted on the eye, and changes in the magnet angle as the eye rotated were detected by a magnetic field sensor. Systematic testing demonstrated high resolution measurements of eye position of eye tracking offers several advantages over the well-established eye coil and video-oculography methods. Most notably, it provides the first method for reliable, high-resolution measurement of eye movements in freely moving mice, revealing increased eye movements and altered binocular coordination compared to head-fixed mice. Overall, magnetic eye tracking provides a lightweight, inexpensive, easily implemented, and high-resolution method suitable for a wide range of applications.

  12. Magnum Survey: Investigating 10 Local Active Galaxies With The Integral Field Eye of MUSE

    Science.gov (United States)

    Venturi, Giacomo; Marconi, A.; Cresci, G.; Carniani, S.; Risaliti, G.

    2016-10-01

    In this talk I will present the first results from the MAGNUM survey (Measuring Active Galactic Nuclei Under MUSE Microscope), which is aimed at exploiting the unique combination of large field of view and spectral range provided by MUSE for detailed physical studies of the interaction of AGN outflows with their host galaxies and of the connection between AGN activity and star formationData have been obtained for about ten galaxies so far, including the famous NGC 1068, NGC 1365, Circinus and NGC 4945. MUSE has allowed us to map the AGN-driven outflows in several different emission lines revealing a clear kinematical and spatial structure related to the ionisation cone and which depends on line excitation. Further insight has been gained by comparing emission line maps from MUSE with high resolution X-ray images from Chandra. Finally, possible evidence for star formation triggered by AGN outflows has been found.

  13. A cathode material based on the iron fluoride with an ultra-thin Li3FeF6 protective layer for high-capacity Li-ion batteries

    Science.gov (United States)

    Yang, Juan; Xu, Zhanglin; Zhou, Haochen; Tang, Jingjing; Sun, Hongxu; Ding, Jing; Zhou, Xiangyang

    2017-09-01

    Iron fluoride based on the multi-electron reaction is a typical representative among the new-style cathode materials for Lithium-ion batteries, which is attracting extensive attentions. To relieve the cathode dissolution and interfacial side reactions and improve the electrochemical performance of FeF3·0.33H2O, we design an ultra-thin Li3FeF6 protective layer, which is in-situ formed on the surface of FeF3·3H2O particles by a facile process. The prepared Li3FeF6/FeF3·0.33H2O (LF50) composite displays a superior rate performance (152 mAh g-1 at 1000 mA g-1), which is remarkable to many other carbon-free iron fluorides. And it is noticeable that a reversible capacity of 174 mAh g-1 can be retained after 100 cycles, indicating an outstanding cycling stability contrast to the bare FeF3·0.33H2O. The enhanced electrochemical performance is attributed to the protection of Li3FeF6 layer which reduces the cathode dissolution and interfacial side reactions. Moreover, the agglomeration of first particles in the calcination process is effectively suppressed resulting from the introduction of the Li3FeF6 protective layer, which promotes electrolyte penetration and charge transfer in the composites. It is expected that the strategy can provide a new approach for the modification of other metal fluoride.

  14. Eye Injuries

    Science.gov (United States)

    The structure of your face helps protect your eyes from injury. Still, injuries can damage your eye, sometimes severely enough that you could lose your vision. Most eye injuries are preventable. If you play sports or ...

  15. Eye Wear

    Science.gov (United States)

    Eye wear protects or corrects your vision. Examples are Sunglasses Safety goggles Glasses (also called eyeglasses) Contact ... jobs and some sports carry a risk of eye injury. Thousands of children and adults get eye ...

  16. Eye Cancer

    Science.gov (United States)

    Cancer of the eye is uncommon. It can affect the outer parts of the eye, such as the eyelid, which are made up ... adults are melanoma and lymphoma. The most common eye cancer in children is retinoblastoma, which starts in ...

  17. Eye Diseases

    Science.gov (United States)

    ... the back of the eye Macular degeneration - a disease that destroys sharp, central vision Diabetic eye problems ... defense is to have regular checkups, because eye diseases do not always have symptoms. Early detection and ...

  18. Multiple Visual Field Representations in the Visual Wulst of a Laterally Eyed Bird, the Zebra Finch (Taeniopygia guttata)

    Science.gov (United States)

    2016-01-01

    The visual wulst is the telencephalic target of the avian thalamofugal visual system. It contains several retinotopically organised representations of the contralateral visual field. We used optical imaging of intrinsic signals, electrophysiological recordings, and retrograde tracing with two fluorescent tracers to evaluate properties of these representations in the zebra finch, a songbird with laterally placed eyes. Our experiments revealed that there is some variability of the neuronal maps between individuals and also concerning the number of detectable maps. It was nonetheless possible to identify three different maps, a posterolateral, a posteromedial, and an anterior one, which were quite constant in their relation to each other. The posterolateral map was in contrast to the two others constantly visible in each successful experiment. The topography of the two other maps was mirrored against that map. Electrophysiological recordings in the anterior and the posterolateral map revealed that all units responded to flashes and to moving bars. Mean directional preferences as well as latencies were different between neurons of the two maps. Tracing experiments confirmed previous reports on the thalamo-wulst connections and showed that the anterior and the posterolateral map receive projections from separate clusters within the thalamic nuclei. Maps are connected to each other by wulst intrinsic projections. Our experiments confirm that the avian visual wulst contains several separate retinotopic maps with both different physiological properties and different thalamo-wulst afferents. This confirms that the functional organization of the visual wulst is very similar to its mammalian equivalent, the visual cortex. PMID:27139912

  19. Multiple Visual Field Representations in the Visual Wulst of a Laterally Eyed Bird, the Zebra Finch (Taeniopygia guttata.

    Directory of Open Access Journals (Sweden)

    Hans-Joachim Bischof

    Full Text Available The visual wulst is the telencephalic target of the avian thalamofugal visual system. It contains several retinotopically organised representations of the contralateral visual field. We used optical imaging of intrinsic signals, electrophysiological recordings, and retrograde tracing with two fluorescent tracers to evaluate properties of these representations in the zebra finch, a songbird with laterally placed eyes. Our experiments revealed that there is some variability of the neuronal maps between individuals and also concerning the number of detectable maps. It was nonetheless possible to identify three different maps, a posterolateral, a posteromedial, and an anterior one, which were quite constant in their relation to each other. The posterolateral map was in contrast to the two others constantly visible in each successful experiment. The topography of the two other maps was mirrored against that map. Electrophysiological recordings in the anterior and the posterolateral map revealed that all units responded to flashes and to moving bars. Mean directional preferences as well as latencies were different between neurons of the two maps. Tracing experiments confirmed previous reports on the thalamo-wulst connections and showed that the anterior and the posterolateral map receive projections from separate clusters within the thalamic nuclei. Maps are connected to each other by wulst intrinsic projections. Our experiments confirm that the avian visual wulst contains several separate retinotopic maps with both different physiological properties and different thalamo-wulst afferents. This confirms that the functional organization of the visual wulst is very similar to its mammalian equivalent, the visual cortex.

  20. Personal Identification by Eyes

    OpenAIRE

    Marinović, Dunja; Čoklo, Miran; Njirić, Sanja; Mužić, Vedrana

    2011-01-01

    Identification of persons through the eyes is in the field of biometrical science. Many security systems are based on biometric methods of personal identification, to determine whether a person is presenting itself truly. The human eye contains an extremely large number of individual characteristics that make it particularly suitable for the process of identifying a person. Today, the eye is considered to be one of the most reliable body parts for human identification. Systems usi...

  1. Infrared Eye: Prototype 2

    Science.gov (United States)

    2016-06-07

    within the wide field and slaved to the operator’s line of sight by means of an eye- tracking system. The images from both cameras are fused and shown...simultaneously on a high resolution CRT display unit, interfaced with the eye- tracking unit in order to optimize the human-machine interface. The IR Eye...system was flight tested using the Advanced system Research Aircraft (Bell 412 helicopter) from the Flight Research Laboratory of the National Research

  2. Nanosecond pulsed electric field suppresses development of eyes and germ cells through blocking synthesis of retinoic acid in Medaka (Oryzias latipes.

    Directory of Open Access Journals (Sweden)

    Eri Shiraishi

    Full Text Available Application of nanosecond pulsed electric fields (nsPEFs has attracted rising attention in various scientific fields including medical, pharmacological, and biological sciences, although its effects and molecular mechanisms leading to the effects remain poorly understood. Here, we show that a single, high-intensity (10-30 kV/cm, 60-ns PEF exposure affects gene expression and impairs development of eyes and germ cells in medaka (Oryzias latipes. Exposure of early blastula stage embryos to nsPEF down-regulated the expression of several transcription factors which are essential for eye development, causing abnormal eye formation. Moreover, the majority of the exposed genetic female embryos showed a fewer number of germ cells similar to that of the control (unexposed genetic male at 9 days post-fertilization (dpf. However, all-trans retinoic acid (atRA treatment following the exposure rescued proliferation of germ cells and resumption of normal eye development, suggesting that the phenotypes induced by nsPEF are caused by a decrease of retinoic acid levels. These results confirm that nsPEFs induce novel effects during embryogenesis in medaka.

  3. Driving with binocular visual field loss? A study on a supervised on-road parcours with simultaneous eye and head tracking.

    Directory of Open Access Journals (Sweden)

    Enkelejda Kasneci

    Full Text Available Post-chiasmal visual pathway lesions and glaucomatous optic neuropathy cause binocular visual field defects (VFDs that may critically interfere with quality of life and driving licensure. The aims of this study were (i to assess the on-road driving performance of patients suffering from binocular visual field loss using a dual-brake vehicle, and (ii to investigate the related compensatory mechanisms. A driving instructor, blinded to the participants' diagnosis, rated the driving performance (passed/failed of ten patients with homonymous visual field defects (HP, including four patients with right (HR and six patients with left homonymous visual field defects (HL, ten glaucoma patients (GP, and twenty age and gender-related ophthalmologically healthy control subjects (C during a 40-minute driving task on a pre-specified public on-road parcours. In order to investigate the subjects' visual exploration ability, eye movements were recorded by means of a mobile eye tracker. Two additional cameras were used to monitor the driving scene and record head and shoulder movements. Thus this study is novel as a quantitative assessment of eye movements and an additional evaluation of head and shoulder was performed. Six out of ten HP and four out of ten GP were rated as fit to drive by the driving instructor, despite their binocular visual field loss. Three out of 20 control subjects failed the on-road assessment. The extent of the visual field defect was of minor importance with regard to the driving performance. The site of the homonymous visual field defect (HVFD critically interfered with the driving ability: all failed HP subjects suffered from left homonymous visual field loss (HL due to right hemispheric lesions. Patients who failed the driving assessment had mainly difficulties with lane keeping and gap judgment ability. Patients who passed the test displayed different exploration patterns than those who failed. Patients who passed focused longer on

  4. Driving with binocular visual field loss? A study on a supervised on-road parcours with simultaneous eye and head tracking.

    Science.gov (United States)

    Kasneci, Enkelejda; Sippel, Katrin; Aehling, Kathrin; Heister, Martin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

    2014-01-01

    Post-chiasmal visual pathway lesions and glaucomatous optic neuropathy cause binocular visual field defects (VFDs) that may critically interfere with quality of life and driving licensure. The aims of this study were (i) to assess the on-road driving performance of patients suffering from binocular visual field loss using a dual-brake vehicle, and (ii) to investigate the related compensatory mechanisms. A driving instructor, blinded to the participants' diagnosis, rated the driving performance (passed/failed) of ten patients with homonymous visual field defects (HP), including four patients with right (HR) and six patients with left homonymous visual field defects (HL), ten glaucoma patients (GP), and twenty age and gender-related ophthalmologically healthy control subjects (C) during a 40-minute driving task on a pre-specified public on-road parcours. In order to investigate the subjects' visual exploration ability, eye movements were recorded by means of a mobile eye tracker. Two additional cameras were used to monitor the driving scene and record head and shoulder movements. Thus this study is novel as a quantitative assessment of eye movements and an additional evaluation of head and shoulder was performed. Six out of ten HP and four out of ten GP were rated as fit to drive by the driving instructor, despite their binocular visual field loss. Three out of 20 control subjects failed the on-road assessment. The extent of the visual field defect was of minor importance with regard to the driving performance. The site of the homonymous visual field defect (HVFD) critically interfered with the driving ability: all failed HP subjects suffered from left homonymous visual field loss (HL) due to right hemispheric lesions. Patients who failed the driving assessment had mainly difficulties with lane keeping and gap judgment ability. Patients who passed the test displayed different exploration patterns than those who failed. Patients who passed focused longer on the

  5. Generation of eye field/optic vesicle-like structures from human embryonic stem cells under two-dimensional and chemically defined conditions.

    Science.gov (United States)

    Parvini, Maryam; Parivar, Kazem; Safari, Fatemeh; Tondar, Mahdi

    2015-03-01

    Despite the enormous progress in studying retinal cell differentiation from human embryonic stem cells (hESCs), none of the reported protocols have produced a cost-effective eye field cells with the capability to further differentiate into retinal derivatives. In this study, by drawing chemicals on our four-step differentiation strategy, we demonstrated the ability of hESCs in assembling such qualifications to follow human retinogenesis in a serum- and feeder-free adherent condition. Two-dimensional (2D) populations of eye field cells arose within early forebrain progeny upon hESCs differentiation. Gene expression analysis showed that the treatment of hESCs with a combination of selected small molecules (SMs) gave rise to the higher expressions of eye field-specific genes, PAX6, RX, and SIX3. Thereafter, a subset of cells gained the transient features of advancing retinal differentiation, including optic vesicle (OV)-like structures, which expressed MITF and CHX10 in a manner imitated in vivo human retinal development. The competency of derived cells in differentiation to retinal derivatives was further investigated. The gene analysis of the cells showed more propensity for generating retinal pigment epithelial (RPE) than neural retina (NR). The generation of OV-like structures in 2D cultures can shed light on molecular events governing retinal specification. It can also facilitate the study of human retinal development.

  6. Lithium intercalation mechanism into FeF3·0.5H2O as a highly stable composite cathode material

    Science.gov (United States)

    Ali, Ghulam; Lee, Ji–Hoon; Chang, Wonyoung; Cho, Byung-Won; Jung, Hun-Gi; Nam, Kyung-Wan; Chung, Kyung Yoon

    2017-01-01

    The growing demand for lithium-ion batteries (LIBs) requires investigation of high-performance electrode materials with the advantages of being environmentally friendly and cost-effective. In this study, a nanocomposite of open-pyrochlore-structured FeF3·0.5H2O and reduced graphene oxide (RGO) is synthesized for use as a high-performance cathode in LIBs, where RGO provides high electrical conductivity to the composite material. The morphology of the composite shows that FeF3·0.5H2O spheres are embedded into RGO layers and high-resolution TEM image shows that those spheres are composed of primary nanoparticles with a size of ~5 nm. The cycling performance indicates that the composite electrode delivers an initial high discharge capacity of 223 mAh g−1 at 0.05 C, a rate capability up to a high C-rate of 10 C (47 mAh g−1) and stable cycle performance at 0.05 C (145 mAh g−1 after 100 cycles) and 0.2 C (93 mAh g−1 after 100 cycles) while maintaining high electrochemical reversibility. Furthermore, the responsible electrochemical reaction is investigated using in-situ XRD and synchrotron-based X-ray absorption spectroscopy (XAS), and the XRD results show that FeF3·0.5H2O transitions to an amorphous-like phase through a lithiation process. However, a reversible oxidation change of Fe3+ ↔ Fe2+ is identified by the XAS results. PMID:28169373

  7. Lithium intercalation mechanism into FeF3·0.5H2O as a highly stable composite cathode material

    Science.gov (United States)

    Ali, Ghulam; Lee, Ji–Hoon; Chang, Wonyoung; Cho, Byung-Won; Jung, Hun-Gi; Nam, Kyung-Wan; Chung, Kyung Yoon

    2017-02-01

    The growing demand for lithium-ion batteries (LIBs) requires investigation of high-performance electrode materials with the advantages of being environmentally friendly and cost-effective. In this study, a nanocomposite of open-pyrochlore-structured FeF3·0.5H2O and reduced graphene oxide (RGO) is synthesized for use as a high-performance cathode in LIBs, where RGO provides high electrical conductivity to the composite material. The morphology of the composite shows that FeF3·0.5H2O spheres are embedded into RGO layers and high-resolution TEM image shows that those spheres are composed of primary nanoparticles with a size of ~5 nm. The cycling performance indicates that the composite electrode delivers an initial high discharge capacity of 223 mAh g‑1 at 0.05 C, a rate capability up to a high C-rate of 10 C (47 mAh g‑1) and stable cycle performance at 0.05 C (145 mAh g‑1 after 100 cycles) and 0.2 C (93 mAh g‑1 after 100 cycles) while maintaining high electrochemical reversibility. Furthermore, the responsible electrochemical reaction is investigated using in-situ XRD and synchrotron-based X-ray absorption spectroscopy (XAS), and the XRD results show that FeF3·0.5H2O transitions to an amorphous-like phase through a lithiation process. However, a reversible oxidation change of Fe3+ ↔ Fe2+ is identified by the XAS results.

  8. Eye Anatomy

    Science.gov (United States)

    ... News About Us Donate In This Section Eye Anatomy en Español email Send this article to a ... You at Risk For Glaucoma? Childhood Glaucoma Eye Anatomy Five Common Glaucoma Tests Glaucoma Facts and Stats ...

  9. Eye trauma

    African Journals Online (AJOL)

    2011-02-02

    Feb 2, 2011 ... will invariably lead to lid swelling, making the examination far more difficult. ... protect the eye with a pad or shield, give tetanus prophylaxis and refer. ... A study on penetrating eye injuries in South African children found.

  10. Prearcuate cortex in the Cebus monkey has cortical and subcortical connections like the macaque frontal eye field and projects to fastigial-recipient oculomotor-related brainstem nuclei.

    Science.gov (United States)

    Leichnetz, G R; Gonzalo-Ruiz, A

    1996-01-01

    The cortical and subcortical connections of the prearcuate cortex were studied in capuchin monkeys (Cebus apella, albifrons) using the anterograde and retrograde transport capabilities of the horseradish peroxidase technique. The findings demonstrate remarkable similarities to those of the macaque frontal eye field and strongly support their homology. The report then focuses on specific prearcuate projections to oculomotor-related brainstem nuclei that were shown in a companion experiment to entertain connections with the caudal oculomotor portion of the cerebellar fastigial nucleus. The principal corticocortical connections of the cebus prearcuate cortex were with dorsomedial prefrontal cortex, lateral intraparietal sulcal cortex, posterior medial parietal cortex, and superior temporal sulcal cortex, which were for the most part reciprocal and columnar in organization. The connections of the dorsal prearcuate region were heavier to the dorsomedial prefrontal and posterior medial parietal cortices, and those of the ventral region were heavier to the superior temporal sulcal cortex. The prearcuate cortex projects to several brainstem areas which also receive projections from the caudal fastigial nucleus, including the supraoculomotor periaqueductal gray matter, superior colliculus, medial nucleus reticularis tegmenti pontis, dorsomedial basilar pontine nucleus, dorsolateral basilar pontine nucleus, nucleus reticularis pontis caudalis, pontine raphe, and nucleus prepositus hypoglossi. The findings define a neuroanatomical framework within which convergence of prearcuate (putative frontal eye field) and caudal fastigial nucleus connections might occur, facilitating their potential interaction in saccadic and smooth pursuit eye movement.

  11. Magnetostructural correlations for Fe2+ ions at orthorhombic sites in FeCl2·4H2O and FeF2·4H2O crystals modeled by microscopic spin Hamiltonian approach

    Science.gov (United States)

    Zając, Magdalena; Lipiński, Ignacy Eryk; Rudowicz, Czesław

    2016-03-01

    The microscopic spin Hamiltonian (MSH) theory developed up to the fourth-order perturbation theory for 3d4 and 3d6 ions with spin S=2 within the 5D approximation is employed to predict the zero field splitting (ZFS) parameters and the Zeeman electronic (Ze) ones. The SH parameters, measurable by electron magnetic resonance (EMR), are expressed in terms of the microscopic parameters, i.e. the spin-orbit (λ), spin-spin (ρ) coupling constants, and the crystal-field (ligands-field) energy levels (∆i) within the 5D multiplet. The energies, ∆i, are indirectly related with structural data, thus enabling investigation of magnetostructural correlations. As a case study Fe2+ (3d6; S=2) ions at orthorhombic sites in FeCl2·4H2O and FeF2·4H2O crystals are considered. Calculations of the ZFS and Ze parameters are carried out for wide ranges of values of the microscopic parameters using the package MSH/VBA. Dependence of the theoretically determined ZFS parameters bkq (in the Stevens notation) and the Zeeman factors gi on λ, ρ, and ∆i is examined and suitable graphs are presented. The absolute value of dominant ZFS parameter |b20| is predicted to be in the range from nearly 8.5 to 1.4 cm-1. Matching the theoretical SH parameters and the experimental ones enables determination of the suitable values of λ, ρ, and ∆i. The fourth-rank ZFS parameters and the ρ(spin-spin)-related contributions, considered for the first time here, are found important. The MSH predictions may be verified and fine-tuned by high-magnetic field and high-frequency EMR measurements. The method employed here and the present results may be also useful for other structurally related systems.

  12. Personal identification by eyes.

    Science.gov (United States)

    Marinović, Dunja; Njirić, Sanja; Coklo, Miran; Muzić, Vedrana

    2011-09-01

    Identification of persons through the eyes is in the field of biometrical science. Many security systems are based on biometric methods of personal identification, to determine whether a person is presenting itself truly. The human eye contains an extremely large number of individual characteristics that make it particularly suitable for the process of identifying a person. Today, the eye is considered to be one of the most reliable body parts for human identification. Systems using iris recognition are among the most secure biometric systems.

  13. Quantification of the ultraviolet radiation (UVR) field in the human eye in vivo using novel instrumentation and the potential benefits of UVR blocking hydrogel contact lens

    OpenAIRE

    Walsh, J; Bergmanson, J.; Wallace, D; Saldana, G.; Dempsey, H.; McEvoy, H.; Collum, L.

    2001-01-01

    BACKGROUND/AIMS—Certain degenerative eye conditions occur predominantly nasally, at the limbal region, and are associated with solar ultraviolet radiation (UVR) induced damage. The relative contribution to the in vivo ocular flux of (a) the reflection of UVR incident on the skin of the nose onto the nasal limbus, and (b) the focusing of UVR incident on the temporal side of the cornea onto the nasal limbus were examined.
METHODS—A novel photodiode sensor array was used to measure the UVR field...

  14. Eye movement suppression interferes with construction of object-centered spatial reference frames in working memory

    DEFF Research Database (Denmark)

    Wallentin, Mikkel; Kristensen, Line Burholt; Olsen, Jacob Hedeager

    2011-01-01

    of an object-centered, rather than egocentric, spatial reference frame. In this behavioral experiment we wanted to demonstrate a causal relationship between eye movement control and manipulation of spatial reference frames. Sixty two participants recalled either spatial ("Was X in front of Y?") or non...... were significantly slower for spatial relations with distraction while there was no effect on non-spatial relations. There was no effect on accuracy, i.e. WM maintenance. This is consistent with the hypothesis that in spatial representations the FEFs are involved in WM content manipulation......, such as establishing an object-centered spatial frame of reference....

  15. Applications of lobster eye optics

    Science.gov (United States)

    Hudec, R.; Pina, L.; Inneman, A.; Tichy, V.

    2015-05-01

    Applications of wide field Lobster Eye X ray telescopes are presented and discussed. The wide field X ray optics was originally proposed for use in X-ray astronomy, but there are numerous other application areas as well.

  16. Diabetes eye exams

    Science.gov (United States)

    Diabetic retinopathy - eye exams; Diabetes - eye exams; Glaucoma - diabetic eye exam; Macular edema - diabetic eye exam ... if the doctor who takes care of your diabetes checks your eyes, you need an eye exam ...

  17. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd Reviewed By: ... your eyes do not produce enough tears, it is called dry eye. Dry eye is also when ...

  18. Facts About Pink Eye

    Science.gov (United States)

    ... Information > Pink Eye (Conjunctivitis) > Facts About Pink Eye Facts About Pink Eye Pink eye is one of ... for preventing eye infections. Last Reviewed: November 2015 Fact Sheet Blurb The National Eye Institute (NEI) is ...

  19. Dilating Eye Drops

    Science.gov (United States)

    ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ...

  20. Dual-illumination mode, wide-field probe imaging scheme for imaging irido-corneal angle region inside eye

    Science.gov (United States)

    Shinoj, V. K.; Murukeshan, V. M.; Hong, Jesmond; Baskaran, M.; Aung, Tin

    2015-07-01

    Noninvasive medical imaging techniques have generated great interest and high potential in the research and development of ocular imaging and follow up procedures. It is well known that angle closure glaucoma is one of the major ocular diseases/ conditions that causes blindness. The identification and treatment of this disease are related primarily to angle assessment techniques. In this paper, we illustrate a probe-based imaging approach to obtain the images of the angle region in eye. The proposed probe consists of a micro CCD camera and LED/NIR laser light sources and they are configured at the distal end to enable imaging of iridocorneal region inside eye. With this proposed dualmodal probe, imaging is performed in light (white visible LED ON) and dark (NIR laser light source alone) conditions and the angle region is noticeable in both cases. The imaging using NIR sources have major significance in anterior chamber imaging since it evades pupil constriction due to the bright light and thereby the artificial altering of anterior chamber angle. The proposed methodology and developed scheme are expected to find potential application in glaucoma disease detection and diagnosis.

  1. Your Eyes

    Science.gov (United States)

    ... eyes to see millions of colors. Helping You See It All Rods and cones process the light to give you the total picture. You're ... get cloudy, causing a cataract . A cataract prevents light from reaching the retina and makes it difficult to see. The eyes you have will be yours forever — ...

  2. Eyes - bulging

    Science.gov (United States)

    ... emotional support is important. When to Contact a Medical Professional Call your health care provider if: You have bulging eyes and the cause has not yet been diagnosed. Bulging eyes are accompanied by other symptoms. ... The provider will ask about your medical history and do a physical exam. Some questions ...

  3. Eye Disease and Development

    DEFF Research Database (Denmark)

    Andersen, Thomas Barnebeck; Dalgaard, Carl-Johan Lars; Selaya, Pablo

    This research advances the hypothesis that cross-country variation in the historical incidence of eye disease has influenced the current global distribution of per capita income. The theory is that pervasive eye disease diminished the incentive to accumulate skills, thereby delaying the fertility...... transition and the take-off to sustained economic growth. In order to estimate the influence from eye disease incidence empirically, we draw on an important fact from the field of epidemiology: Exposure to solar ultraviolet B radiation (UVB-R) is an underlying determinant of several forms of eye disease...... are robust to the inclusion of an extensive set of climate and geography controls. Moreover, using a global data set on economic activity for all terrestrial grid cells we show that the link between UVB-R and economic development survives the inclusion of country fixed effect....

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd Reviewed By: Brenda Pagan- ...

  5. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué Es el Ojo Seco? ...

  6. Miniature curved artificial compound eyes.

    Science.gov (United States)

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L'Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A; Franceschini, Nicolas

    2013-06-04

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories.

  7. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Eye Symptoms Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd ... your vision. Privacy Policy Related New Dry Eye Treatment is a Tear-Jerker Jul 21, 2017 Three ...

  8. Diabetic Eye Disease

    Science.gov (United States)

    ... Other Dental Problems Diabetes & Sexual & Urologic Problems Diabetic Eye Disease What is diabetic eye disease? Diabetic eye disease is a group of ... loss can occur. How does diabetes affect my eyes? Diabetes affects your eyes when your blood glucose, ...

  9. Study and Design on Freeform Surface Compound Eye with Large Field of View%大视场自由曲面复眼设计研究

    Institute of Scientific and Technical Information of China (English)

    范阳; 张红霞; 宋乐; 贾大功

    2014-01-01

    The ommatidia arranged at the edge have great off-axis aberrations in artificial compound eye structure with wide Field of View (FOV) and small volume. A new compound eye structure is presented, where the ommatidia are designed as freeform prisms. With the light passing through the freeform surface and folding in the ommatidium, the off-axis aberrations are well corrected. Therefore, the image quality of the ommatidia arranged at the edge is improved, and the FOV of the structure is enlarged. To image 180° FOV, this structure contains 5 groups of ommatidia with a particular FOV correspondingly. The model of each group is designed and the ray trace is completed based on the optical simulation software codeV. The results demonstrate that the compound eyes structure has high image quality for the entire 180° FOV. On the one hand, the modulation transformation function MTF is greater than 0.2 at the frequency of 100lp/mm, and on the other hand, the distortion is less than 30%.%在大视场小体积的人造复眼结构中,倾斜的边缘子眼成像时存在较大的轴外像差。提出一种复眼结构,利用光线在子眼中的折转与自由曲面矫正像差,提高了边缘子眼的成像质量,进而增大了复眼结构的视场角。设计出5组子眼对180°视场成像,每组对应特定的视场范围。利用光学仿真软件CodeV对5组子眼分别做了光学仿真,得到了各组子眼的像差曲线,光学传递函数 MTF 曲线。结果表明,在整个180°视场范围内,频率为100 lp/mm时,MTF值均大于0.2,畸变在30%以内,复眼具有良好的成像质量。

  10. Aboveground biomass estimation using SAR-optical (Lidar, RapidEye) and field inventory datasets in Skukuza, Kruger National Park in South Africa

    Science.gov (United States)

    Onyango Odipo, Victor; Hüttich, Christian; Luck, Wolfgang; Schmullius, Christiane

    2015-04-01

    African savanna covers approximately two-thirds of sub-saharan Africa, playing important roles as a carbon pool, habitat for mankind and wildlife, source of livelihood, an important tropical climate modifier, among other ecological roles. Sub-saharan Africa alone accounts for 25% of the tropical aboveground carbon stock (193 Gt C). Global and national level AGB estimates rely on extrapolations with regression models from few field inventories, leading in some cases, up to 100% uncertainty. Remote sensing has proven to provide reliable vegetation structural mapping, given the high spatial and temporal resolution allowing datasets to be availed in areas where ground based inventories are infeasible due to time and financial constraints. The availability of freely accessible optical remotely-sensed datasets has made this feat attainable. However, the heterogeneity of tropical savannas (co-existence of trees and grasses), coupled with erratic rainfall events and atmospheric clouds and aerosol in the tropics has made it difficult to extract biophysical properties of the savannas by solely using optical datasets. This has necessitated an assessment of synergies between active and passive remotely sensed datasets to benefit from the complementarities. In this study we assess the extent to which multi-level sub-centimeter Unmanned Aerial Vehicle (UAV) Lidar, high resolution RapidEye and microwave (ALOS PALSAR L-band and Sentinel-1 C-band) remotely sensed datasets can be used together with tree census datasets to estimate AGB within the complex southern Africa savanna ecosystem. A random forest (RF) regression model is produced which relates the Lidar canopy-height metrics (CHM) with both synthetic aperture radar (SAR) and high resolution RapidEye datasets. As a validation, we compare our results with both national and global level ABG estimates.

  11. Microwave Assisted Convenient One-Pot Synthesis of Coumarin Derivatives via Pechmann Condensation Catalyzed by FeF3 under Solvent-Free Conditions and Antimicrobial Activities of the Products

    Directory of Open Access Journals (Sweden)

    Vahid Vahabi

    2014-08-01

    Full Text Available A rapid and efficient solvent-free one-pot synthesis of coumarin derivatives by Pechmann condensation reactions of phenols with ethyl acetoacetate using FeF3 as a catalyst under microwave irradiation is described. This one-pot synthesis on a solid inorganic support provides the products in good yields. The newly synthesized compounds were systematically characterized by IR, 1H-NMR, 13C-NMR, MS and elemental CHN analyses. The proposed solvent-free microwave irradiation method using the environmentally friendly catalyst FeF3 offers the unique advantages of high yields, shorter reaction times, easy and quick isolation of the products, excellent chemoselectivity, and a one-pot, green synthesis. The products were screened for antimicrobial activity, and the results showed that the compounds reacted against all the tested bacteria.

  12. High-resolution corneal topography and tomography of fish eye using wide-field white light interference microscopy

    Science.gov (United States)

    Srivastava, Vishal; Nandy, Sreyankar; Singh Mehta, Dalip

    2013-04-01

    Topography and tomography of fish cornea is reconstructed using high resolution white light interference microscopy. White light interferograms at different depths were recorded by moving the object axially. For each depth position, five phase shifted interferograms were recorded and analyzed. From the reconstructed phase maps, the corneal topography and hence the refractive index was determined and from amplitude images the cross-sectional image of fish cornea was reconstructed. In the present method, we utilize a nearly common-path interference microscope and wide field illumination and hence do not require any mechanical B-scan. Therefore, the phase stability of the recorded data is improved.

  13. Your Eyes

    Science.gov (United States)

    ... people you know — like your grandparents — probably wear glasses. To the Brain! Think of the optic nerve as the great messenger in the back of your eye. The rods and cones of the retina change the colors and shapes you see into millions of nerve ...

  14. Dorsal eye selector pannier (pnr) suppresses the eye fate to define dorsal margin of the Drosophila eye

    Science.gov (United States)

    Oros, Sarah M.; Tare, Meghana; Kango-Singh, Madhuri; Singh, Amit

    2010-01-01

    Axial patterning is crucial for organogenesis. During Drosophila eye development, dorso-ventral (DV) axis determination is the first lineage restriction event. The eye primordium begins with a default ventral fate, on which the dorsal eye fate is established by expression of the GATA-1 transcription factor pannier (pnr). Earlier, it was suggested that loss of pnr function induces enlargement in the dorsal eye due to ectopic equator formation. Interestingly, we found that in addition to regulating DV patterning, pnr suppresses the eye fate by downregulating the core retinal determination genes eyes absent (eya), sine oculis (so) and dacshund (dac) to define the dorsal eye margin. We found that pnr acts downstream of Ey and affect the retinal determination pathway by suppressing eya. Further analysis of the “eye suppression” function of pnr revealed that this function is likely mediated through suppression of the homeotic gene teashirt (tsh) and is independent of homothorax (hth), a negative regulator of eye. Pnr expression is restricted to the peripodial membrane on the dorsal eye margin, which gives rise to head structures around the eye, and pnr is not expressed in the eye disc proper that forms the retina. Thus, pnr has dual function, during early developmental stages pnr is involved in axial patterning whereas later it promotes the head specific fate. These studies will help in understanding the developmental regulation of boundary formation of the eye field on the dorsal eye margin. PMID:20691679

  15. Design of hyper-field zoom bionic eye optical system%超大视场变焦仿生眼光学系统设计

    Institute of Scientific and Technical Information of China (English)

    程洪涛; 吴勇翀; 吕杰; 张培茗; 郭世俊; 李恒宇

    2016-01-01

    提出了一种新的基于仿生鱼眼镜头模型的超大视场变焦仿生眼光学系统。该仿生眼应用可调光焦度器件能使光学系统更紧凑和不需要移动。鉴于鱼眼系统可以简化成反远物镜的原理,利用矩阵理论和变焦准则,研究了基于可调光焦度器件鱼眼镜头设计的一阶几何光学理论,得到了鱼眼系统前组和后组的光焦度控制方程;进一步讨论了其光焦度的边界方程;最后提供的仿生变焦鱼眼的视场角最大为164°,焦距从5~15 mm变化,成像质量达到系统要求。设计实例为其在智能监控、航天军工、机器人系统等领域的应用提供了有益的探索。%A new hyper-field zoom bionic eye optical system based on the model of bionic fisheye was presented. The variable focal power lens was employed to design the bionic eye with zoom system more compact and no move lens. The fisheye lens is a kind of retro-focus lens system. Fisheye zoom first-order geometric optics theory based on matrix theory and zoom principle were established. The former group and the latter group focusing optical power equation were deduced. Furthermore, the boundary equation of optical power in the zoom system was discussed. Finally, the bionic fisheye field can be acquire to 164o. The focal lengths was from 5 mm to 15 mm. The design example can be applied in intelligent control, aerospace industry, robotics systems which provide a useful exploration.

  16. The MAGNUM survey: outflows and star formation in ten local Seyfert galaxies with the integral field eye of MUSE

    Science.gov (United States)

    Venturi, G.; Marconi, A.; Cresci, G.; Risaliti, G.; Carniani, S.; Mannucci, F.

    2016-08-01

    In this talk I will present the first results from the MAGNUM survey (Measuring Active Galactic Nuclei Under MUSE Microscope), which takes advantage of the unprecedented combination of the large field of view and spectral coverage of MUSE so as to carry out a detail study of the interaction of AGN outflows with the host galaxies and of the relation between AGN activity and star formation. The data comprise ten nearby galaxies so far, such as NGC 1365, NGC 1068 and Circinus. The analysis of MUSE data in many different emission lines has allowed to disentangle the various motions of the gas in the central regions of the galaxies (rotation, outflows and inflows), furthermore resolving the structure of the AGN-ionised cone. Other information of the separate phases of the gas (having different temperature, density and ionisation state) has been obtained thanks to the comparison with high resolution X-ray Chandra images. Moreover, possible evidence for star formation triggered by AGN outflows has been observed.

  17. Why Do Eyes Water?

    Science.gov (United States)

    ... Lifesaver Kids Talk About: Coaches Why Do Eyes Water? KidsHealth > For Kids > Why Do Eyes Water? Print ... out of your nose. continue Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  18. Eye muscle repair - discharge

    Science.gov (United States)

    ... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye muscle ... term for crossed eyes is strabismus. Children most often ...

  19. Why Do Eyes Water?

    Science.gov (United States)

    ... Happens in the Operating Room? Why Do Eyes Water? KidsHealth > For Kids > Why Do Eyes Water? A ... out of your nose. continue Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  20. About the Eye

    Medline Plus

    Full Text Available ... eye behind the iris that helps to focus light on the retina. It allows the eye to ... of the eye. It regulates the amount of light entering the eye through the pupil. Pupil (PYOO- ...

  1. Recommended Sports Eye Protectors

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  2. Eye Safety at Home

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  3. Eye Safety at Work

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  4. Eye Movement Disorders

    Science.gov (United States)

    ... work properly. There are many kinds of eye movement disorders. Two common ones are Strabismus - a disorder in ... the eyes, sometimes called "dancing eyes" Some eye movement disorders are present at birth. Others develop over time ...

  5. About the Eye

    Medline Plus

    Full Text Available ... eye behind the iris that helps to focus light on the retina. It allows the eye to ... of the eye. It regulates the amount of light entering the eye through the pupil. Pupil (PYOO- ...

  6. Conjunctivitis (Pink Eye)

    Science.gov (United States)

    ... that can be embedded on web pages. Conjunctivitis (Pink Eye) One-Page Overview Pink, itchy eyes? Conjunctivitis – ... protect yourself from getting and spreading pink eye . Pink Eye: What To Do Discusses causes and treatment, ...

  7. Eye Disease Simulations

    Science.gov (United States)

    ... USAJobs Home > Eye Health Information > Eye Disease Simulations Eye Disease Simulations Age-Related Macular Degeneration Cataract Diabetic ... information page Back to top Diabetic Retinopathy Diabetic Eye Disease information page Back to top Glaucoma Glaucoma ...

  8. Eye Involvement in TSC

    Science.gov (United States)

    ... Privacy Policy Sitemap Learn Engage Donate About TSC Eyes Campbell (1905) first described the eye involvement in ... some form of eye involvement. Nonretinal and Retinal Eye Findings Facial angiofibromas may involve the eyelids of ...

  9. Eye Complications in IBD

    Science.gov (United States)

    ... Home > Resources > Eye Complications in IBD Go Back Eye Complications in IBD Email Print + Share Approximately 10% ... doctor’s attention sooner rather than later. TYPES OF EYE DISORDERS UVEITIS One of the most common eye ...

  10. Effect of a pulsed magnetic field on permeability of the cornea and sorption properties of the tissue structures and refractive media of the eye

    Energy Technology Data Exchange (ETDEWEB)

    Skrinnik, A.V.

    1986-03-01

    The author attempts to obtain direct proof of increased permeability of the cornea and enhanced sorption properties of the tissue structures and refractive media of the eye under the influence of a pulsed magnetic field (MF). In the course of the investigation, the method of radioactive indication of two substances (/sup 35/S-streptomycin and /sup 75/Se-methionine), widely used in opthalmologic practice, was used. The radioactivity of the working solution of the preparations was 300,000 cpm in 0.1 ml. Changes in the permeability of the cornea were assessed on the basis of changes in radioactivity of the aqueous humor. The concentration of /sup 35/S-streptomycin in aqueous humor of the animals immediately after exposure to MF was significantly higher than in the control. Analysis of permeability of the cornea for /sup 75/Se-methionine also showed increased penetration of radioactivity into the aqueous. The results are evidence of the greater penetrating power of /sup 75/Se-methionine.

  11. Eye Contricks

    Directory of Open Access Journals (Sweden)

    Nicholas J Wade

    2011-06-01

    Full Text Available Pictorial images are icons as well as eye-cons: they provide distillations of objects or ideas into simpler shapes. They create the impression of representing that which cannot be presented. Even at the level of the photograph, the links between icon and object are tenuous. The dimensions of depth and motion are missing from icons, and these alone introduce all manner of potential ambiguities. The history of art can be considered as exploring the missing link between icon and object. Eye-cons can also be illusions—tricks of vision so that what is seen does not necessarily correspond to what is physically presented. Pictorial images can be spatialised or stylised; spatialised images generally share some of the projective characteristics of the object represented. Written words are also icons, but they do not resemble the objects they represent—they are stylised or conventional. Icons as stylised words and spatialised images were set in delightful opposition by René Magritte in a series of pipe paintings, and this theme is here alluded to. Most of visual science is now concerned with icons—two-dimensional displays on computer monitors. Is vision now the science of eye-cons?

  12. "Eye Science" in 2011

    Institute of Scientific and Technical Information of China (English)

    Jian Ge

    2011-01-01

    @@ 2011 is an opportune time for Yanke Xuebao (Eye Science) to launch its bilingual edition as a platform for cooperation between Chinese and international vision researchers.The yearly research output of Chinese investigators in all fields of science, but particularly biomedicine, has been growing recently by leaps and bounds.As an example, the American Journal of Ophthalmology (AJO), one of the most prestigious clinical journals in our field,received more submissions from East Asian authors (Japan, China and Korea alone)than they did from the United States in 2010.Chinese investigators ranked third on the list, climbing rapidly, only after the US and Japan.Top vision research centers in China, such as Zhongshan Ophthalmic Center, where Eye Science is published, now rank alongside Moorfields and Johns Hopkins as among the most prolific institutions in the world, measured by articles appearing annually in peer-reviewed SCI journals.

  13. Prognostic value of tumour blood flow, [{sup 18}F]EF5 and [{sup 18}F]FDG PET/CT imaging in patients with head and neck cancer treated with radiochemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Komar, Gaber; Eskola, Olli; Sipilae, Hannu; Solin, Olof [Turku PET Centre, Turku (Finland); Lehtioe, Kaisa; Levola, Helena; Lindholm, Paula; Seppaelae, Jan [Turku University Hospital and University of Turku, Department of Oncology and Radiotherapy, Turku (Finland); Seppaenen, Marko [Turku PET Centre, Turku (Finland); Turku University Hospital and University of Turku, Department of Nuclear Medicine, Turku (Finland); Grenman, Reidar [Turku University Hospital and University of Turku, Department of Otorhinolaryngology, Head and Neck Surgery, Turku (Finland); Minn, Heikki [Turku PET Centre, Turku (Finland); Turku University Hospital and University of Turku, Department of Oncology and Radiotherapy, Turku (Finland)

    2014-11-15

    In order to improve the treatment of squamous cell carcinoma of the head and neck, precise information on the treated tumour's biology is required and the prognostic importance of different biological parameters needs to be determined. The aim of our study was to determine the predictive value of pretreatment PET/CT imaging using [{sup 18}F]FDG, a new hypoxia tracer [{sup 18}F]EF5 and the perfusion tracer [{sup 15}O]H{sub 2}O in patients with squamous cell cancer of the head and neck treated with radiochemotherapy. The study group comprised 22 patients with confirmed squamous cell carcinoma of the head and neck who underwent a PET/CT scan using the above tracers before any treatment. Patients were later treated with a combination of radiochemotherapy and surgery. Parametric blood flow was calculated from dynamic [{sup 15}O]H{sub 2}O PET images using a one-tissue compartment model. [{sup 18}F]FDG images were analysed by calculating standardized uptake values (SUV) and metabolically active tumour volumes (MATV). [{sup 18}F]EF5 images were analysed by calculating tumour-to-muscle uptake ratios (T/M ratio). A T/M ratio of 1.5 was considered a significant threshold and used to determine tumour hypoxic subvolumes (HS) and hypoxic fraction area. The findings were finally correlated with the pretreatment clinical findings (overall stage and TNM stage) as well as the outcome following radiochemotherapy in terms of local control and overall patient survival. Tumour stage and T-classification did not show any significant differences in comparison to the patients' metabolic and functional characteristics measured on PET. Using the Cox proportional hazards model, a shorter overall survival was associated with MATV (p = 0.008, HR = 1.108), maximum [{sup 18}F]EF5 T/M ratio (p = 0.0145, HR = 4.084) and tumour HS (p = 0.0047, HR = 1.112). None of the PET parameters showed a significant effect on patient survival in the log-rank test, although [{sup 18}F]EF5 maximum T

  14. Abnormal MEG oscillatory activity during visual processing in the prefrontal cortices and frontal eye-fields of the aging HIV brain.

    Directory of Open Access Journals (Sweden)

    Tony W Wilson

    Full Text Available OBJECTIVE: Shortly after infection, HIV enters the brain and causes widespread inflammation and neuronal damage, which ultimately leads to neuropsychological impairments. Despite a large body of neuroscience and imaging studies, the pathophysiology of these HIV-associated neurocognitive disorders (HAND remains unresolved. Previous neuroimaging studies have shown greater activation in HIV-infected patients during strenuous tasks in frontal and parietal cortices, and less activation in the primary sensory cortices during rest and sensory stimulation. METHODS: High-density magnetoencephalography (MEG was utilized to evaluate the basic neurophysiology underlying attentive, visual processing in older HIV-infected adults and a matched non-infected control group. Unlike other neuroimaging methods, MEG is a direct measure of neural activity that is not tied to brain metabolism or hemodynamic responses. During MEG, participants fixated on a centrally-presented crosshair while intermittent visual stimulation appeared in their top-right visual-field quadrant. All MEG data was imaged in the time-frequency domain using beamforming. RESULTS: Uninfected controls had increased neuronal synchronization in the 6-12 Hz range within the right dorsolateral prefrontal cortex, right frontal eye-fields, and the posterior cingulate. Conversely, HIV-infected patients exhibited decreased synchrony in these same neural regions, and the magnitude of these decreases was correlated with neuropsychological performance in several cortical association regions. CONCLUSIONS: MEG-based imaging holds potential as a noninvasive biomarker for HIV-related neuronal dysfunction, and may help identify patients who have or may develop HAND. Reduced synchronization of neural populations in the association cortices was strongly linked to cognitive dysfunction, and likely reflects the impact of HIV on neuronal and neuropsychological health.

  15. 不同视觉区域OUP效应的眼动研究%An Eye Movement Research of OUP Effects in Different Fields of Vision

    Institute of Scientific and Technical Information of China (English)

    唐浩; 韩玉昌; 于爱华

    2011-01-01

    The researches of word recognition have been the hot topics in recent years. The result of that is the processes model of word recognition contains two different models, sequential processes model and parallel models. The controversies between them are still to now, so is very urgent to sort out to deal with the problems. On the basis of other researcher' s theory and experiment, this study investigated the OUP effects in English words, by examining the OUP effects in the left (LVF) and right (RVF) fields of vision, provided a more limpid evidence for the process strategy when recognized the words in the cerebral. By using the technology of eye movement, the present investigation examined the word recognition strategies on left and right hemispheres performance, the results confirmed the presence of sequential processes model. Experiment 1 investigated the OUP effects in English words when presented horizontally to the LVF and RVF. We asked participants to judge the meaning of English words and Chinese characters with an early or late orthographic uniqueness point (OUP) presented horizontally to their LVF and RVF. When the participants gaze the OUP words, we use the eye tracker to trace the eye movement in different fields of vision. Consistent with the past foveal research, Experiment i produced a robust facilitatory effect of early OUP for RVF presentation, indicating the presence of sequential process in lexical retrieval. The effect was absent for LVF trials, which we argue this result from the disadvantaged position of initial letters of words presented in the LVF. Experiment 2 replicated Experiment 1 using vertical stimulus presentations to investigate the OUP effects in different fields of vision. We want to know how the participants process the OUP words when they are vertically presented. Results indicated a marked faeilitatory effect of early OUP across visual field, supporting our contention that the lack of OUP effect for LVF presentations

  16. Eye Contricks

    Directory of Open Access Journals (Sweden)

    N Wade

    2011-04-01

    Full Text Available Icons are eye-cons: they provide a distillation of a complex object or idea into a simple pictorial shape. They create the impression of representing that which cannot be presented. Even at the level of the photograph, the links between icon and object are tenuous. The dimension of distance or depth is missing from the icon, and this alone introduces all manner of potential ambiguities. The history of art can be considered as an exploration of the missing link between icon and object. Eye-cons are more honest—they are tricks of vision so that what is seen does not necessarily correspond to what is presented. They are visual allusions rather than visual illusions, although they can display illusory effects. At its broadest, icon can be equated with image. The concept of image has thrived on its vagueness, and so attempts have been made to refine it. An icon corresponds to an optical image: it shares some of the projective characteristics of the object represented. Written words are also icons but they do not resemble the objects they represent—they are stylised or conventional rather than spatialised and projective. Words and images were set in delightful opposition by René Magritte (1898-1967 in a series of pipe paintings, and he also played on the theme of the arbitrariness of the verbal labels assigned to objects. What is surprising is that Magritte did not apply his painterly skills to transforming the word shapes he used. A similar reluctance to transform the typefaces pervades visual poetry. My interests are in the visual rather than the poetic dimension, and I will present a range of my own eye contricks which play with letter and word shapes in a variety of ways.

  17. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Dry Eye ... Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué Es el Ojo Seco? Written By: Kierstan ...

  18. About the Eye

    Medline Plus

    Full Text Available ... Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More Information Optical Illusions Printables About the Eye Your eyes ...

  19. About the Eye

    Medline Plus

    Full Text Available ... Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More Information Optical Illusions Printables About the Eye Your eyes ...

  20. Mechanically stable nanostructures with desirable characteristic field enhancement factors: a response from scale invariance in electrostatics

    Science.gov (United States)

    de Assis, Thiago A.; Dall'Agnol, Fernando F.

    2016-11-01

    This work presents an accurate numerical study of the electrostatics of a system formed by individual nanostructures mounted on support substrate tips, which provides a theoretical prototype for applications in field electron emission or for the construction of tips in probe microscopy that requires high resolution. The aim is to describe the conditions to produce structures mechanically robust with desirable field enhancement factor (FEF). We modeled a substrate tip with a height h 1, radius r 1 and characteristic FEF {γ }1, and a top nanostructure with a height h 2, radius {r}2\\lt {r}1 and FEF {γ }2, for both hemispheres on post-like structures. The nanostructure mounted on the support substrate tip then has a characteristic FEF, {γ }{{C}}. Defining the relative difference {η }{{R}}=({γ }{{C}}-{γ }1)/({γ }3-{γ }1), where {γ }3 corresponds to the reference FEF for a hemisphere of the post structure with a radius {r}3={r}2 and height {h}3={h}1+{h}2, our results show, from a numerical solution of Laplace’s equation using a finite element scheme, a scaling {η }{{R}}=f(u\\equiv λ {θ }-1), where λ \\equiv {h}2/{h}1 and θ ={r}1/{r}2. Given a characteristic variable u c, for u\\ll {u}{{c}}, we found a power law {η }{{R}}˜ {u}κ , with κ ≈ 0.55. For u\\gg {u}{{c}}, {η }{{R}}\\to 1, which led to conditions where {γ }{{C}}\\to {γ }3. As a consequence of scale invariance, it is possible to derive a simple expression for {γ }{{C}} and to predict the conditions needed to produce related systems with a desirable FEF that are robust owing to the presence of the substrate tip. Finally, we discuss the validity of Schottky’s conjecture (SC) for these systems, showing that, while to obey SC is indicative of scale invariance, the opposite is not necessarily true. This result suggests that a careful analysis must be performed before attributing SC as an origin of giant FEF in experiments.

  1. EyeGENE

    Data.gov (United States)

    U.S. Department of Health & Human Services — The eyeGENE® Biorepository and corresponding Database contain family history and clinical eye exam data from subjects enrolled in eyeGENE® Program coupled to...

  2. Eye Injuries in Sports

    Science.gov (United States)

    ... in Sports Which sports cause the most eye injuries?Sports cause more than 40,000 eye injuries each ... and racquet sports.When it comes to eye injuries, sports can be classified as low risk, high risk ...

  3. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Member Services Advocacy Foundation About Subspecialties & More Eye Health Home Annual Meeting Clinical Education Practice Management Member ... Center Redmond Ethics Center Global Ophthalmology Guide Eye Health Find an Ophthalmologist Academy Store Eye Health A- ...

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Member Services Advocacy Foundation About Subspecialties & More Eye Health Home Annual Meeting Clinical Education Practice Management Member ... Center Redmond Ethics Center Global Ophthalmology Guide Eye Health Find an Ophthalmologist Academy Store Eye Health A- ...

  5. Eye muscle repair - slideshow

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/presentations/100062.htm Eye muscle repair - series—Normal anatomy To use the sharing ... the eyeball to the eye socket. The external muscles of the eye are found behind the conjunctiva. ...

  6. Pink Eye (Conjunctivitis)

    Science.gov (United States)

    ... you have allergic conjunctivitis. Preventing the spread of pink eye Practice good hygiene to control the spread ... can return to school or child care. Preventing pink eye in newborns Newborns' eyes are susceptible to ...

  7. About the Eye

    Medline Plus

    Full Text Available ... Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision ... to More Information Optical Illusions Printables About the Eye Your eyes are made up of many different ...

  8. About the Eye

    Science.gov (United States)

    ... Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision ... to More Information Optical Illusions Printables About the Eye Your eyes are made up of many different ...

  9. Eye Injuries (For Parents)

    Science.gov (United States)

    ... Habits for TV, Video Games, and the Internet Eye Injuries KidsHealth > For Parents > Eye Injuries Print A ... sand, dirt, and other foreign bodies on the eye surface) Wash your hands thoroughly before touching the ...

  10. Laser photocoagulation - eye

    Science.gov (United States)

    Laser coagulation; Laser eye surgery; Photocoagulation; Laser photocoagulation - diabetic eye disease; Laser photocoagulation - diabetic retinopathy; Focal photocoagulation; Scatter (or pan retinal) photocoagulation; Proliferative ...

  11. Surgical Treatment of Laser Induced Eye Injuries

    Science.gov (United States)

    1990-12-05

    AD-A234 849 CONTRACT NO.: DAMD17-89-C-9026 TITLE: SURGICAL TREATMENT OF LASER INDUCED EYE INJURIES AUTHORS: Leonard M. Hjelmeland, Maurice B. Landers...62787A 62787A878 BA JDA318205 11. TITLE (Include Secirity Classification) (U) Surgical Treatment of Laser Induced Eye Injuries 12. PERSONAL AUTHOR(S...TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP RA 3; Lasers; Eye injury ; Surgery 09 03 06 04 19. ABSTRACT

  12. Wave field characterization for non-destructive assessment of elastic properties using laser-acoustic sources in fluids and eye related tissues

    Science.gov (United States)

    Windisch, T.; Schubert, F.; Köhler, B.; Spörl, E.

    2010-03-01

    The age-related changes in the visco-elastic properties of the human lens are discussed with respect to presbyopia for a long time. All known measurement techniques are based on extracted lenses or are damaging the tissue. Hence, in vivo studies of lens hardness are not possible at the moment. To close this gap in lens diagnostics this project deals with an approach for a non-contact laser-acoustic characterization technique. Laser-generated wave fronts are reflected by the tissue interfaces and are also affected by the visco-elastic properties of the lens tissue. After propagating through the eye, these waves are recorded as corneal vibrations by laser vibrometry. A systematic analysis of amplitude and phase of these signals and the wave generation process shall give information about the interface locations and the tissues viscoelastic properties. Our recent studies on extracted porcine eyes proved that laser-acoustic sources can be systematically used for non-contacting generation and recording of ultrasound inside the human eye. Furthermore, a specific numerical model provides important contributions to the understanding of the complex wave propagation process. Measurements of the acoustic sources support this approach. Future investigations are scheduled to answer the question, whether this novel technique can be directly used during a laser surgery for monitoring purposes and if a purely diagnostic approach, e.g. by excitation in the aqueous humor, is also possible. In both cases, this technique offers a promising approach for non-contact ultrasound based eye diagnostics.

  13. Eating for Your Eyes

    Science.gov (United States)

    Stastny, Sherri Nordstrom; Garden-Robinson, Julie

    2011-01-01

    An educational program targeting older adults was developed to increase knowledge regarding nutrition and eye health. With age, the chance for eye disease increases, so prevention is critical. The Eating for Your Eyes program has promoted behavior changes regarding eye health among the participants. This program is easily replicated and use is…

  14. Eye Injuries (For Parents)

    Science.gov (United States)

    ... the eye nausea or vomiting after an eye injury Think Prevention! Kids who play sports should wear protective goggles or unbreakable glasses as needed. Keep chemicals and other potentially dangerous objects out of the reach of children. Reviewed by: Steven Dowshen, ... (Conjunctivitis) Eyes Corneal Abrasions Styes Activity: Eyes ...

  15. Eye tracking in Library and Information Science

    DEFF Research Database (Denmark)

    Lund, Haakon

    2016-01-01

    . Subsequently, a growing interest in employing eye tracking as a methodology within library and information science research must be anticipated. Design/methodology/approach The review follows the guidelines set in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. Two......, the number of test persons and reports on the eye-tracking measures. Furthermore, this study will report which other methods were applied in combination with eye tracking. Findings The number of published research utilizing eye-tracking technologies within library and information science (LIS) is still......Purpose The purpose of this paper is to present a systematic literature review of the application of eye-tracking technology within the field of library and information science. Eye-tracking technology has now reached a level of maturity, which makes the use of the technology more accessible...

  16. Machine learning for multi-view eye-pair detection

    NARCIS (Netherlands)

    Karaaba, Mahir Faik; Schomaker, Lambert; Wiering, Marco

    2014-01-01

    While face and eye detection is well known research topics in the field of object detection, eye-pair detection has not been much researched. Finding the location and size of an eye-pair in an image containing a face can enable a face recognition application to extract features from a face correspon

  17. Machine learning for multi-view eye-pair detection

    NARCIS (Netherlands)

    Karaaba, Mahir Faik; Schomaker, Lambert; Wiering, Marco

    While face and eye detection is well known research topics in the field of object detection, eye-pair detection has not been much researched. Finding the location and size of an eye-pair in an image containing a face can enable a face recognition application to extract features from a face

  18. The eyes of man as a photic bisensor system

    NARCIS (Netherlands)

    Verheijen, F.J.; Fingal, J.A.

    1982-01-01

    Non-patterned photic stimulation of the eyes of human subjects was obtained by homogeneous illumination of the closed eyes. The subjects perceived a difference between the stimulation intensity of the left and of the right eye as a field of view consisting of a bright and a dark half, adjoined acros

  19. The eyes of man as a photic bisensor system

    NARCIS (Netherlands)

    Verheijen, F.J.; Fingal, J.A.

    1982-01-01

    Non-patterned photic stimulation of the eyes of human subjects was obtained by homogeneous illumination of the closed eyes. The subjects perceived a difference between the stimulation intensity of the left and of the right eye as a field of view consisting of a bright and a dark half, adjoined acros

  20. Eye Drop Tips

    Science.gov (United States)

    ... Involved News About Us Donate In This Section Eye Drop Tips en Español email Send this article ... the reach of children. Steps For Putting In Eye Drops: Start by tilting your head backward while ...

  1. What Is Dry Eye?

    Medline Plus

    Full Text Available ... information about eye health and preserving your vision. Privacy Policy Related New Dry Eye Treatment is a ... the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media ...

  2. What Is Dry Eye?

    Medline Plus

    Full Text Available ... is also when your eyes do not make the right type of tears. How do tears work? ... you blink, a film of tears spreads over the eye. This keeps the eye’s surface smooth and ...

  3. What Is Dry Eye?

    Medline Plus

    Full Text Available ... tissue covering the white of your eye and inside your eyelids. Normally, our eyes constantly make tears ... Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical ...

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Eye ... What Is Dry Eye? Leer en Español: ¿Qué ...

  5. TUBERCULOSIS AND THE EYE

    African Journals Online (AJOL)

    Key words: Mycobacteria; Tuberculosis; Eye ... of tuberculous eye disease or ocular tuberculosis has also been raised. Ocular ... patients with ocular complaints, compiled in an area ..... tuberculomas are usually solitary and may measure up.

  6. About the Eye

    Medline Plus

    Full Text Available ... you see. Check out the diagrams below to learn about each part of your eye and what ... the optic nerve to the brain. Watch now! Learn how the different parts of your eye work ...

  7. About the Eye

    Medline Plus

    Full Text Available ... The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid ... Your eyes are made up of many different parts that work together to help you see. Check out the ...

  8. What Is Dry Eye?

    Medline Plus

    Full Text Available ... about eye health and preserving your vision. Privacy Policy Related New Dry Eye Treatment is a Tear- ... Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology ...

  9. Preventing eye injuries

    Directory of Open Access Journals (Sweden)

    Daksha Patel

    2016-01-01

    Full Text Available The main challenge in developing a strategy to prevent eye injuries is that there are so many different causes and situations that can lead to eye injuries, each requiring a different approach.

  10. Common Eye Disorders

    Science.gov (United States)

    ... www.cdc.gov/emailupdates/">What's this? Submit Button Common Eye Disorders Recommend on Facebook Tweet Share Compartir ... macular degeneration, cataract, diabetic retinopathy, and glaucoma. Other common eye disorders include amblyopia and strabismus. For a ...

  11. The all seeing eye?

    NARCIS (Netherlands)

    Koenderink, Jan J.

    2014-01-01

    The All Seeing Eye? Did you know that you are probably a believer in the All Seeing Eye? The odds are that I’m right—why? Well, the bulk of mainstream vision literature blindly relies on the All Seeing Eye. It is written all over papers, albeit between the lines. Understandably so, for scientists re

  12. About the Eye

    Medline Plus

    Full Text Available ... other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health ... Eye Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and ...

  13. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Dry Eye ... when I sleep? Feb 10, 2016 Leer en Español: ¿Qué Es el Ojo Seco? Find an Ophthalmologist ...

  14. About the Eye

    Medline Plus

    Full Text Available ... other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health ... Eye Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and ...

  15. The all seeing eye?

    NARCIS (Netherlands)

    Koenderink, Jan J.|info:eu-repo/dai/nl/070864543

    2014-01-01

    The All Seeing Eye? Did you know that you are probably a believer in the All Seeing Eye? The odds are that I’m right—why? Well, the bulk of mainstream vision literature blindly relies on the All Seeing Eye. It is written all over papers, albeit between the lines. Understandably so, for scientists

  16. Medicare Benefits and Your Eyes

    Science.gov (United States)

    ... Subscribe to eNews Close Donate Medicare Benefits & Your Eyes Eye Health is Important! As you age, your risk ... that you need. Ask about eye exams! Routine Eye Exams Medicare does not generally cover the costs ...

  17. Prevent Eye Injuries from Fireworks

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  18. EYE GAZE TRACKING

    DEFF Research Database (Denmark)

    2017-01-01

    This invention relates to a method of performing eye gaze tracking of at least one eye of a user, by determining the position of the center of the eye, said method comprising the steps of: detecting the position of at least three reflections on said eye, transforming said positions to spanning...... a normalized coordinate system spanning a frame of reference, wherein said transformation is performed based on a bilinear transformation or a non linear transformation e.g. a möbius transformation or a homographic transformation, detecting the position of said center of the eye relative to the position...... of said reflections and transforming this position to said normalized coordinate system, tracking the eye gaze by tracking the movement of said eye in said normalized coordinate system. Thereby calibration of a camera, such as knowledge of the exact position and zoom level of the camera, is avoided...

  19. Real Time Eye Template Detection and Tracking

    Directory of Open Access Journals (Sweden)

    Richa Mehta

    2012-06-01

    Full Text Available There has been a growing interest in the field of facial expression recognition especially in the last two decades. An example of such a system is the improvement of driver carefulness and accident reduction. The driver’s face is tracked while he is driving and he is warned if there seems to be an alerting fact that can result in an accident such as sleepy eyes, or looking out of the road. Furthermore, with a facial feature tracker, it becomes possible to play a synthesized avatar so that it imitates the expressions of the performer. Human-Computer Interaction (HCI systems may also be enriched by a facial feature tracker. For a user who is incapable of using her hands, a facial expression controller may be a solution to send limited commands to a computer. Eye blinking is one of the prominent areas to solve many real world problems. The process of blink detection consists of two phases. These are eye tracking followed by detection of blink. The work that has been carried out for eye tracking only is not suitable for eye blink detection. Therefore some approaches had been proposed for eye tracking along with eyes blink detection. In this thesis, real time implementation is done to count number of eye blinks in an image sequence. At last after analyzing all these approaches some of the parameters we obtained on which better performance of eye blink detection algorithm depend. This project focuses on automatic eye blink detection in real time. The aim of this thesis is to count the number of eye blinks in a video. This project will be performed on a video database of the facial expressions.

  20. Eye shape and peripheral visual field recording in high myopia at approximately 54 years of age, as based on ultrasonography and Goldmann kinetic perimetry

    DEFF Research Database (Denmark)

    Fledelius, Hans C; Goldschmidt, Ernst

    2010-01-01

    This study describes the posterior pole contour and visual field (VF) findings in an unselected series of adults (aged approximately 54 years) with high myopia.......This study describes the posterior pole contour and visual field (VF) findings in an unselected series of adults (aged approximately 54 years) with high myopia....

  1. 1st Workshop on Eye Tracking and Visualization

    CERN Document Server

    Chuang, Lewis; Fisher, Brian; Schmidt, Albrecht; Weiskopf, Daniel

    2017-01-01

    This book discusses research, methods, and recent developments in the interdisciplinary field that spans research in visualization, eye tracking, human-computer interaction, and psychology. It presents extended versions of papers from the First Workshop on Eye Tracking and Visualization (ETVIS), which was organized as a workshop of the IEEE VIS Conference 2015. Topics include visualization and visual analytics of eye-tracking data, metrics and cognitive models, eye-tracking experiments in the context of visualization interfaces, and eye tracking in 3D and immersive environments. The extended ETVIS papers are complemented by a chapter offering an overview of visualization approaches for analyzing eye-tracking data and a chapter that discusses electrooculography (EOG) as an alternative of acquiring information about eye movements. Covering scientific visualization, information visualization, and visual analytics, this book is a valuable resource for eye-tracking researchers within the visualization community.

  2. Light emission from compound eye with conformal fluorescent coating

    Science.gov (United States)

    Martín-Palma, Raúl J.; Miller, Amy E.; Pulsifer, Drew P.; Lakhtakia, Akhlesh

    2015-03-01

    Compound eyes of insects are attractive biological systems for engineered biomimicry as artificial sources of light, given their characteristic wide angular field of view. A blowfly eye was coated with a thin conformal fluorescent film, with the aim of achieving wide field-of-view emission. Experimental results showed that the coated eye emitted visible light and that the intensity showed a weaker angular dependence than a fluorescent thin film deposited on a flat surface.

  3. An improved likelihood model for eye tracking

    DEFF Research Database (Denmark)

    Hammoud, Riad I.; Hansen, Dan Witzner

    2007-01-01

    approach in such cases is to abandon the tracking routine and re-initialize eye detection. Of course this may be a difficult process due to missed data problem. Accordingly, what is needed is an efficient method of reliably tracking a person's eyes between successively produced video image frames, even...... are challenging. It proposes a log likelihood-ratio function of foreground and background models in a particle filter-based eye tracking framework. It fuses key information from even, odd infrared fields (dark and bright-pupil) and their corresponding subtractive image into one single observation model...

  4. Ivermectin for onchocercal eye disease (river blindness)

    OpenAIRE

    Ejere, HO; Schwartz, E; Wormald, R; Evans, JR

    2012-01-01

    BACKGROUND: It is believed that ivermectin (a microfilaricide) could prevent blindness due to onchocerciasis. However, when given to everyone in communities where onchocerciasis is common, the effects of ivermectin on lesions affecting the eye are uncertain and data on whether the drug prevents visual loss are unclear. OBJECTIVES: The aim of this review was to assess the effectiveness of ivermectin in preventing visual impairment and visual field loss in onchocercal eye disease. The secondary...

  5. An evaluation of the WindEye wind lidar

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Sjöholm, Mikael; Mann, Jakob

    Prevision of the wind field by remote sensing wind lidars has the potential to improve the performance of wind turbines. The functionality of a WindEye lidar developed by Windar Photonics A/S (Denmark) for the wind energy market was tested in a two months long field experiment. The WindEye sensor...

  6. Teamwork for eye care

    Directory of Open Access Journals (Sweden)

    M Babar Qureshi

    2014-04-01

    Full Text Available Human resource development (HRD – the development of the people who deliver health care – has been identified as one of the key pillars of eye health delivery. HRD is one of the essential building blocks of the World Health Organization (WHO Global Action Plan: ‘Towards universal eye health’. The importance of HRD is also recognised beyond eye care, as can be seen in the WHO Health Systems approach.

  7. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Academy Publications EyeNet Ophthalmology Ophthalmology Retina Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians and Nurses Senior Ophthalmologists ...

  8. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics ... Services Advocacy Foundation About Subspecialties & More Eye ...

  9. Impaired Saccadic Eye Movement in Primary Open-angle Glaucoma

    DEFF Research Database (Denmark)

    Lamirel, Cédric; Milea, Dan; Cochereau, Isabelle

    2013-01-01

    PURPOSE:: Our study aimed at investigating the extent to which saccadic eye movements are disrupted in patients with primary open-angle glaucoma (POAG). This approach followed upon the discovery of differences in the eye-movement behavior of POAG patients during the exploration of complex visual...... scenes. METHODS:: The eye movements of 8 POAG patients and 4 healthy age-matched controls were recorded. Four of the patients had documented visual field scotoma, and 4 had no identifiable scotoma on visual field testing. The eye movements were monitored as the observers watched static and kinetic...

  10. Eye proprioception may provide real time eye position information.

    Science.gov (United States)

    Wang, Jing; Pan, Yujun

    2013-03-01

    Because of the frequency of eye movements, online knowledge of eye position is crucial for the accurate spatial perception and behavioral navigation. Both the internal monitoring signal (corollary discharge) of eye movements and the eye proprioception signal are thought to contribute to the localization of the eye position in the orbit. However, the functional role of these two eye position signals in spatial cognition has been disputed for more than a century. The predominant view proposes that the online analysis of eye position is exclusively provided by the corollary discharge signal, while the eye proprioception signal only plays a role in the long-term calibration of the oculomotor system. However, increasing evidence from recent behavioral and physiological studies suggests that the eye proprioception signal may play a role in the online monitoring of eye position. The purpose of this review is to discuss the feasibility and possible function of the eye proprioceptive signal for online monitoring of eye position.

  11. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Registry Medicare Physician Payment Meetings and Deadlines Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive ... Registry Medicare Physician Payment Meetings and Deadlines Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive ...

  12. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Deadlines Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive Surgery Museum of Vision Subspecialties Cataract/ ... Deadlines Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive Surgery Museum of Vision Subspecialties Cataract/ ...

  13. About the Eye

    Medline Plus

    Full Text Available ... NIH), the National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the ...

  14. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Emergency Relief EyeCare America Help IRIS Registry Medicare Physician Payment Meetings and Deadlines Ophthalmology Job Center Our ... Emergency Relief EyeCare America Help IRIS Registry Medicare Physician Payment Meetings and Deadlines Ophthalmology Job Center Our ...

  15. About the Eye

    Medline Plus

    Full Text Available ... Optical Illusions Printables About the Eye Your eyes are made up of many different parts that work ... Media Information in Spanish (Información en español) Website, ... Office of Science Communications, Public Liaison, and Education. Technical questions about ...

  16. Eye-Tracking

    Directory of Open Access Journals (Sweden)

    Gabriela GROSSECK

    2006-01-01

    Full Text Available Eye-tracking: one of the newest and most efficient methods of improving on-line marketing communication is called eye-tracking. Marketers have borrowed this technique, usually used in psychological and medical research, in order to study web users with the help of a video camera incorporated in the monitor.

  17. Perception of eye positions

    NARCIS (Netherlands)

    Lorteije, J.A.M.; Wezel, R.J.A. van; Lankheet, M.J.M.

    2002-01-01

    In a two-alternative forced-choice psychophysical test human subjects were tested for their ability to perceive their own viewing direction. A small red flash was presented at different horizontal positions left or right from the subjects' eye position on the screen. Eye positions were recorded with

  18. Understanding pink eye

    Science.gov (United States)

    Pink eye (PE) is a physiological tuber disorder that can result in serious processing complications and storage losses. The earliest external symptoms consist of an ephemeral pinkish discoloration around tuber eyes, predominately at the bud end of the tuber. These pinkish areas can then develop into...

  19. Photorefraction of the Eye

    Science.gov (United States)

    Colicchia, Giuseppe; Wiesner, Hartmut; Zollman, Dean

    2015-01-01

    Photorefraction is a method to easily estimate the refractive state of the eye. The principle of photorefraction involves projecting light into the eye during flash photography and then examining the paths of light that emerge from the pupil after scattering on the back portion of the interior of the eyeball (fundus). We will explain the optical…

  20. Eye tracking social preferences

    NARCIS (Netherlands)

    Jiang, Ting; Potters, Jan; Funaki, Yukihiko

    We hypothesize that if people are motivated by a particular social preference, then choosing in accordance with this preference will lead to an identifiable pattern of eye movements. We track eye movements while subjects make choices in simple three-person distribution experiments. We characterize

  1. BullsEye

    DEFF Research Database (Denmark)

    Klokmose, Clemens Nylandsted; Kristensen, Janus Bager; Bagge, Rolf

    2014-01-01

    implemented primarily in shaders on the GPU. The techniques are realized in the BullsEye computer vision software. We demonstrate experimentally that BullsEye provides sub-pixel accuracy down to a tenth of a pixel, which is a significant improvement compared to the commonly used reacTIVision software....

  2. Generation of functional eyes from pluripotent cells.

    Directory of Open Access Journals (Sweden)

    Andrea S Viczian

    2009-08-01

    Full Text Available Pluripotent cells such as embryonic stem (ES and induced pluripotent stem (iPS cells are the starting point from which to generate organ specific cell types. For example, converting pluripotent cells to retinal cells could provide an opportunity to treat retinal injuries and degenerations. In this study, we used an in vivo strategy to determine if functional retinas could be generated from a defined population of pluripotent Xenopus laevis cells. Animal pole cells isolated from blastula stage embryos are pluripotent. Untreated, these cells formed only epidermis, when transplanted to either the flank or eye field. In contrast, misexpression of seven transcription factors induced the formation of retinal cell types. Induced retinal cells were committed to a retinal lineage as they formed eyes when transplanted to the flanks of developing embryos. When the endogenous eye field was replaced with induced retinal cells, they formed eyes that were molecularly, anatomically, and electrophysiologically similar to normal eyes. Importantly, induced eyes could guide a vision-based behavior. These results suggest the fate of pluripotent cells may be purposely altered to generate multipotent retinal progenitor cells, which differentiate into functional retinal cell classes and form a neural circuitry sufficient for vision.

  3. Eye tracking in Library and Information Science

    DEFF Research Database (Denmark)

    Lund, Haakon

    2016-01-01

    Purpose The purpose of this paper is to present a systematic literature review of the application of eye-tracking technology within the field of library and information science. Eye-tracking technology has now reached a level of maturity, which makes the use of the technology more accessible....... Subsequently, a growing interest in employing eye tracking as a methodology within library and information science research must be anticipated. Design/methodology/approach The review follows the guidelines set in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. Two...... reference databases are searched for relevant references: Library and Information Science Abstracts and Library, Information Science and Technology Abstracts. The main selection criteria are peer-reviewed literature that describes the experimental setting, including which eye-tracking equipment was used...

  4. A psychological perspective of eye floaters.

    Science.gov (United States)

    Cipolletta, Sabrina; Beccarello, Alessandra; Galan, Alessandro

    2012-11-01

    Patients experiencing flashes and spots in their perceptive fields often resort to consulting an ophthalmologist without finding an answer, mainly because these symptoms are not necessarily associated with pathology of the eye. The purpose of our research study was to understand the experience of these patients, differentiate among them, and propose different ways of treating them. We carried out an eye examination and echography, individual semistructured interviews, and dependency grids with 11 patients at the ophthalmology department of a public hospital in northern Italy. We found that individuals' ways of experiencing and reacting to eye floaters might be different and might depend on the perception of the disease, the personal explanation, the solutions tried, the trust placed in medicine, self-construction, and the dispersion of dependency. Understanding the experiences of patients suffering from eye floaters might help health care professionals to personalize their approaches to these patients.

  5. Eye tracking in Library and Information Science

    DEFF Research Database (Denmark)

    Lund, Haakon

    2016-01-01

    . Subsequently, a growing interest in employing eye tracking as a methodology within library and information science research must be anticipated. Design/methodology/approach The review follows the guidelines set in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. Two...... reference databases are searched for relevant references: Library and Information Science Abstracts and Library, Information Science and Technology Abstracts. The main selection criteria are peer-reviewed literature that describes the experimental setting, including which eye-tracking equipment was used......Purpose The purpose of this paper is to present a systematic literature review of the application of eye-tracking technology within the field of library and information science. Eye-tracking technology has now reached a level of maturity, which makes the use of the technology more accessible...

  6. A Bird's-Eye View of Alzheimer's Disease Research: Reflecting Different Perspectives of Indexers, Authors, or Citers in Mapping the Field.

    Science.gov (United States)

    Lee, Dahee; Kim, Won Chul; Charidimou, Andreas; Song, Min

    2015-01-01

    During the last 30 years, Alzheimer's disease (AD) research, aiming to understand the pathophysiology and to improve the diagnosis, management, and, ultimately, treatment of the disease, has grown rapidly. Recently, some studies have used simple bibliometric approaches to investigate research trends and advances in the field. In our study, we map the AD research field by applying entitymetrics, an extended concept of bibliometrics, to capture viewpoints of indexers, authors, or citers. Using the full-text documents with reference section retrieved from PubMed Central, we constructed four types of networks: MeSH-MeSH (MM), MeSH-Citation-MeSH (MCM), Keyphrase-Keyphrase (KK), and Keyphrase-Citation-Keyphrase (KCK) networks. The working hypothesis was that MeSH, keyphrase, and citation relationships reflect the views of indexers, authors, and/or citers, respectively. In comparative network and centrality analysis, we found that those views are different: indexers emphasize amyloid-related entities, including methodological terms, while authors focus on specific biomedical terms, including clinical syndromes. The more dense and complex networks of citing relationships reported in our study, to a certain extent reflect the impact of basic science discoveries in AD. However, none of these could have had clinical relevance for patients without close collaboration between investigators in translational and clinical-related AD research (reflected in indexers and authors' networks). Our approach has relevance for researches in the field, since they can identify relations between different developments which are not otherwise evident. These developments combined with advanced visualization techniques, might aid the discovery of novel interactions between genes and pathways or used as a resource to advance clinical drug development.

  7. Visuomotor transformations for eye-hand coordination.

    Science.gov (United States)

    Henriques, D Y P; Medendorp, W P; Khan, A Z; Crawford, J D

    2002-01-01

    In recent years the scientific community has come to appreciate that the early cortical representations for visually guided arm movements are probably coded in a visual frame, i.e. relative to retinal landmarks. While this scheme accounts for many behavioral and neurophysiological observations, it also poses certain problems for manual control. For example, how are these oculocentric representations updated across eye movements, and how are they then transformed into useful commands for accurate movements of the arm relative to the body? Also, since we have two eyes, which is used as the reference point in eye-hand alignment tasks like pointing? We show that patterns of errors in human pointing suggest that early oculocentric representations for arm movement are remapped relative to the gaze direction during each saccade. To then transform these oculocentric representations into useful commands for accurate movements of the arm relative to the body, the brain correctly incorporates the three-dimensional, rotary geometry of the eyes when interpreting retinal images. We also explore the possibility that the eye-hand coordination system uses a strategy like ocular dominance, but switches alignment between the left and right eye in order to maximize eye-hand coordination in the best field of view. Finally, we describe the influence of eye position on eye-hand alignment, and then consider how head orientation influences the linkage between oculocentric visual frames and bodycentric motor frames. These findings are framed in terms of our 'conversion-on-demand' model, which suggests a virtual representation of egocentric space, i.e. one in which only those representations selected for action are put through the complex visuomotor transformations required for interaction with actual objects in personal space.

  8. 超大视场红外鱼眼告警系统的成像响应特性分析%Imaging response characteristics analysis of ultra-wide field of view infrared fish-eye warning system

    Institute of Scientific and Technical Information of China (English)

    周玉龙; 王永仲

    2011-01-01

    超大视场红外鱼眼告警系统具有凝视半球空域,实时感知来自空中不同方向威胁的独特优点,在未来战争中必将有着广泛的应用.而对超大视场红外鱼眼告警系统的成像响应特性进行分析有助于解决其在应用中所出现的问题.对系统的温度响应特性、时间响应特性以及像面照度进行了分析,结果表明,在相同的环境温度下,系统的温度响应特性是线性的,且随着时间的推移系统的输出逐渐变大,在约70 min以后趋于稳定;当环境温度升高时,系统输出也相应变大,说明系统存在着能量漂移.通过对实验结果的进一步分析,结果表明,这种能量漂移是环境温度和系统的自热效应共同作用的结果.通过对同一目标不同位置处的灰度值进行分析,发现灰度值相对标准偏差仅为2.26%,说明不同位置处目标的灰度值几乎是相等的,从而表明系统的像面照度是均匀的,这与随后的理论分析相一致.对于超大视场红外鱼眼告警系统的算法设计方面具有重要的参考价值.%The ultra-wide field of view(UWFV)infrared fish-eye warning system has the ability of staring hemisphere space so that it can sense the threats from different directions at real time,which makes it be widely used in the future modern wars.It will be helpful in solving the problems in practical application to analyze the thermal imaging response characteristics of UWFV infrared fish-eye warning system.In this paper,the thermal imaging response characteristics including temperature response,time response and image illumination were analyzed respectively for UWFV infrared fish-eye warning system.It was found that under the same ambient temperature condition,the system temperature response was linear.With the process of time,the system output became bigger gradually,and it tended to be a fixed value after about 70 minutes.When the ambient temperature got higher,the system output was also

  9. 基于蛙眼R3细胞感受野模型的运动滤波方法%Motion Filtering by Modelling R3 Cell0s Receptive Field in Frog Eyes

    Institute of Scientific and Technical Information of China (English)

    李智勇; 何霜; 刘俊敏; 李仁发

    2015-01-01

    视觉感受野(Visual receptive field)模型作为生物视觉感知计算的基础单元,在整个生物视觉信息加工过程中发挥着重要作用。借鉴具有运动视觉特长的生物感受野特性研究高效的运动视觉计算技术,是一种潜在可行的方法。本文基于蛙眼R3细胞感受野,在高斯差分模型(Difference of Gaussians, DOG)的基础上引入时间和空间各向异性的运动视觉表达方式,提出一种基于蛙眼R3细胞的不对称各向异性感受野(Asymmetric anisotropy receptive field, AARF)模型,表达蛙类视觉系统对运动目标敏感的视觉时空特征。基于该运动视觉模型,进一步提出了一种面向序列图像运动目标分析的蛙眼时空运动滤波算子(Frog-based spatio-temporal motion filter, FSTMF),以实现运动目标准确检测与分析。实验结果表明,该方法具有使序列图像背景模糊、动态目标突显的滤波效果,既符合蛙眼视觉背景模糊而前景清晰的特性,也为下一步运动目标的准确检测实现了高效的预处理。%As a basic unit of biological visual perception computing, the visual receptive field plays a significant role in the whole process of biological visual information processing. It is a potentially feasible method for further study of efficient computing technology based on motion visual characteristic from biological receptive field. Inspired by frog eye0s R3 cell receptive field, this study introduces a spatio-temporal anisotropy motion visual presentation to the difference of Gaussians (DOG) model. Thus, an asymmetric anisotropy receptive field (AARF) model is presented. This model can express frog visual system0s spatio-temporal characteristic which is sensitive to moving visual targets. Based on the motion visual model, a frog-based spatio-temporal motion filter (FSTMF) is further proposed, which aims at accurate moving object detection and analysis in sequential images and videos. The experimental results

  10. Wide-angle chromatic aberration corrector for the human eye.

    Science.gov (United States)

    Benny, Yael; Manzanera, Silvestre; Prieto, Pedro M; Ribak, Erez N; Artal, Pablo

    2007-06-01

    The human eye is affected by large chromatic aberration. This may limit vision and makes it difficult to see fine retinal details in ophthalmoscopy. We designed and built a two-triplet system for correcting the average longitudinal chromatic aberration of the eye while keeping a reasonably wide field of view. Measurements in real eyes were conducted to examine the level and optical quality of the correction. We also performed some tests to evaluate the effect of the corrector on visual performance.

  11. Eye-head coordination abnormalities in schizophrenia.

    Directory of Open Access Journals (Sweden)

    Simon Schwab

    Full Text Available BACKGROUND: Eye-movement abnormalities in schizophrenia are a well-established phenomenon that has been observed in many studies. In such studies, visual targets are usually presented in the center of the visual field, and the subject's head remains fixed. However, in every-day life, targets may also appear in the periphery. This study is among the first to investigate eye and head movements in schizophrenia by presenting targets in the periphery of the visual field. METHODOLOGY/PRINCIPAL FINDINGS: Two different visual recognition tasks, color recognition and Landolt orientation tasks, were presented at the periphery (at a visual angle of 55° from the center of the field of view. Each subject viewed 96 trials, and all eye and head movements were simultaneously recorded using video-based oculography and magnetic motion tracking of the head. Data from 14 patients with schizophrenia and 14 controls were considered. The patients had similar saccadic latencies in both tasks, whereas controls had shorter saccadic latencies in the Landolt task. Patients performed more head movements, and had increased eye-head offsets during combined eye-head shifts than controls. CONCLUSIONS/SIGNIFICANCE: Patients with schizophrenia may not be able to adapt to the two different tasks to the same extent as controls, as seen by the former's task-specific saccadic latency pattern. This can be interpreted as a specific oculomotoric attentional dysfunction and may support the hypothesis that schizophrenia patients have difficulties determining the relevance of stimuli. Patients may also show an uneconomic over-performance of head-movements, which is possibly caused by alterations in frontal executive function that impair the inhibition of head shifts. In addition, a model was created explaining 93% of the variance of the response times as a function of eye and head amplitude, which was only observed in the controls, indicating abnormal eye-head coordination in patients

  12. Gaze and eye-tracking solutions for psychological research.

    Science.gov (United States)

    Mele, Maria Laura; Federici, Stefano

    2012-08-01

    Eye-tracking technology is a growing field used to detect eye movements and analyze human processing of visual information for interactive and diagnostic applications. Different domains in scientific research such as neuroscience, experimental psychology, computer science and human factors can benefit from eye-tracking methods and techniques to unobtrusively investigate the quantitative evidence underlying visual processes. In order to meet the experimental requirements concerning the variety of application fields, different gaze- and eye-tracking solutions using high-speed cameras are being developed (e.g., eye-tracking glasses, head-mounted or desk-mounted systems), which are also compatible with other analysis devices such as magnetic resonance imaging. This work presents an overview of the main application fields of eye-tracking methodology in psychological research. In particular, two innovative solutions will be shown: (1) the SMI RED-M eye-tracker, a high performance portable remote eye-tracker suitable for different settings, that requires maximum mobility and flexibility; (2) a wearable mobile gaze-tracking device--the SMI eye-tracking glasses--which is suitable for real-world and virtual environment research. For each kind of technology, the functions and different possibilities of application in experimental psychology will be described by focusing on some examples of experimental tasks (i.e., visual search, reading, natural tasks, scene viewing and other information processing) and theoretical approaches (e.g., embodied cognition).

  13. What Is Dry Eye?

    Medline Plus

    Full Text Available ... vision in the morning? Jun 12, 2017 Can lupus affect my vision? May 27, 2017 Is stopping ... Answers Free Newsletter Get ophthalmologist-reviewed tips and information about eye health and preserving your vision. Privacy ...

  14. Anatomy of the Eye

    Science.gov (United States)

    ... Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Anatomy of the Eye En Español Read in Chinese External (Extraocular) Anatomy Extraocular Muscles: There are six muscles that are ...

  15. About the Eye

    Medline Plus

    Full Text Available ... The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips ... addressed to the NEI Website Manager . Department of Health and Human Services | The National Institutes of Health | ...

  16. About the Eye

    Medline Plus

    Full Text Available ... Units Division of Epidemiology and Clinical Applications eyeGENE Research Directors Office Office of the Scientific Director Sheldon S. Miller, Ph.D., Scientific Director David ...

  17. About the Eye

    Medline Plus

    Full Text Available ... of visual function, preservation of sight, and the special health problems and requirements of the blind.” News & ... Emily Y. Chew, M.D., Deputy Clinical Director Education Programs National Eye Health Education Program (NEHEP) Diabetic ...

  18. Eyes, Bulging (Proptosis)

    Science.gov (United States)

    ... a disorder causing overactivity of the thyroid gland ( hyperthyroidism ). Bulging eyes are not the same as prominent ... or pain Whether the person has symptoms of hyperthyroidism, such as inability to tolerate heat, increased sweating, ...

  19. About the Eye

    Medline Plus

    Full Text Available ... The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips ... addressed to the NEI Website Manager . Department of Health and Human Services | The National Institutes of Health | ...

  20. What Is Dry Eye?

    Medline Plus

    Full Text Available ... How do tears work? When you blink, a film of tears spreads over the eye. This keeps the eye’s surface smooth and clear. The tear film is important for good vision. The tear film ...

  1. About the Eye

    Medline Plus

    Full Text Available ... about each part of your eye and what it does. Macula (MACK-yoo-luh) is the small, ... area of the retina needed for central vision. It contains the fovea. Lens is the clear part ...

  2. What Is Eye Cancer?

    Science.gov (United States)

    ... melanomas. Melanomas develop from pigment-making cells called melanocytes . When melanoma develops in the eye, it is ... cells make the same kind of pigment as melanocytes in the skin, so it’s not surprising that ...

  3. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy Publications EyeNet Ophthalmology ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Find an Ophthalmologist Advanced ...

  4. About the Eye

    Medline Plus

    Full Text Available ... Units Division of Epidemiology and Clinical Applications eyeGENE Research Directors Office Office of the Scientific Director Sheldon S. ... Fellowships NEI Summer Intern Program Diversity In Vision Research & Ophthalmology (DIVRO) Student Training Programs To search for ...

  5. Sports and Your Eyes

    Science.gov (United States)

    ... may put you at high risk for eye injuries. Baseball Basketball Water Sports Boxing Hockey Paintball Racquetball Softball Squash Fencing Lacrosse Wrestling Football Golf Badminton Soccer Tennis Fishing Bicycling Gymnastics Track ...

  6. Diabetic Eye Problems

    Science.gov (United States)

    ... damage your eyes. The most common problem is diabetic retinopathy. It is a leading cause of blindness ... You need a healthy retina to see clearly. Diabetic retinopathy damages the tiny blood vessels inside your ...

  7. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy Publications EyeNet Ophthalmology Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians and Nurses ...

  8. About the Eye

    Medline Plus

    Full Text Available ... NEI Women Scientists Advisory Committee (WSAC) Board of Scientific Counselors National Advisory Eye Council (NAEC) Donating to ... Grants and Funding Extramural Research Division of Extramural Science Programs Division of Extramural Activities Extramural Contacts NEI ...

  9. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Eye May 03, 2012 Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical ...

  10. The ageing eye

    African Journals Online (AJOL)

    2007-10-11

    Oct 11, 2007 ... With an increasing elderly population, age-related eye diseases are becoming the leading causes of ... and social health and overall quality of life. Enormous strides are ..... hip fractures, accidents and depression. Conclusion.

  11. Multimodal eye recognition

    Science.gov (United States)

    Zhou, Zhi; Du, Yingzi; Thomas, N. L.; Delp, Edward J., III

    2010-04-01

    Multimodal biometrics use more than one means of biometric identification to achieve higher recognition accuracy, since sometimes a unimodal biometric is not good enough used to do identification and classification. In this paper, we proposed a multimodal eye recognition system, which can obtain both iris and sclera patterns from one color eye image. Gabor filter and 1-D Log-Gabor filter algorithms have been applied as the iris recognition algorithms. In sclera recognition, we introduced automatic sclera segmentation, sclera pattern enhancement, sclera pattern template generation, and sclera pattern matching. We applied kernelbased matching score fusion to improve the performance of the eye recognition system. The experimental results show that the proposed eye recognition method can achieve better performance compared to unimodal biometric identification, and the accuracy of our proposed kernel-based matching score fusion method is higher than two classic linear matching score fusion methods: Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA).

  12. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Dry Eye Symptoms Related Ask an Ophthalmologist Answers Can a six-month dissolvable punctal plug be removed ... insert a permanent punctal plug? Sep 12, 2017 Can you explain why I have halos and blurry ...

  13. Eye Injuries in Construction

    Science.gov (United States)

    ... from a power tool (like a drill or wheel) , OR ! If your eye is cut or punctured : • ... CIO: CPWR, Suite 1000, 8484 Georgia Ave., Silver Spring, MD 20910. (Edward C. Sullivan is president of ...

  14. Applied eye tracking research

    NARCIS (Netherlands)

    Jarodzka, Halszka

    2011-01-01

    Jarodzka, H. (2010, 12 November). Applied eye tracking research. Presentation and Labtour for Vereniging Gewone Leden in oprichting (VGL i.o.), Heerlen, The Netherlands: Open University of the Netherlands.

  15. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide ... What Is Dry Eye? Written By: Kierstan Boyd ...

  16. About the Eye

    Medline Plus

    Full Text Available ... about each part of your eye and what it does. Macula (MACK-yoo-luh) is the small, ... area of the retina needed for central vision. It contains the fovea. Lens is the clear part ...

  17. Toxoplasmosis (and the Eye)

    Science.gov (United States)

    ... cat litter boxes, cat feces, sandboxes, and any insects exposed to cat feces (cockroaches, flies, etc.). Immunocompromised ... rash. Eye symptoms vary, but may include blurred vision or floaters during active disease. The diagnosis can ...

  18. About the Eye

    Medline Plus

    Full Text Available ... programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems and ... Health Information Frequently asked questions ...

  19. Applied eye tracking research

    NARCIS (Netherlands)

    Jarodzka, Halszka

    2011-01-01

    Jarodzka, H. (2010, 12 November). Applied eye tracking research. Presentation and Labtour for Vereniging Gewone Leden in oprichting (VGL i.o.), Heerlen, The Netherlands: Open University of the Netherlands.

  20. Development of the compound eyes of dragonflies (Odonata). III. Adult compound eyes.

    Science.gov (United States)

    Sherk, T E

    1978-01-01

    The distribution of ommatidial diameters and interommatidial angles, as determined by measuring the angles between the optic axes of adjacent ommatidia, are mapped across the surface of the compound eyes of a variety of species selected for different adult behaviors, developmental histories, and taxonomic positions. The size of the visual fields, prey capture foveas, foveas composed of large dorsal ommatidia, and other specializations in the numbers of ommatidia that view various directions in the visual field are discussed in relation to adult behavior. Advanced species have less resemblance between their larval and adult eyes than primitive species. In contrast to their larvae, adults increase the monocular resolution of each eye at the expense of binocular vision. Most species have foveas which view in approximately the anterior direction, instead of in a region of binocular overlap, and many species have foveal bands which view along the horizon. Some advanced perching species, which approach their prey and other odonates from below, have an additional vertical foveal band that views along a vertical plane from the anterior direction to a more dorsal direction. The most unusual foveal band is seen in active flying species. The large dorsal ommatidia of the migratory Anax junius, which cover approximately one third of the eye surface, view a narrow region of the visual field that extends along a plane from the most lateral direction of one eye to a dorsal direction, and continues without interruption to the most lateral direction of the other eye.

  1. Detection of cortical activities on eye movement using functional magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Masaki; Kawai, Kazushige; Kitahara, Kenji [Jikei Univ., Tokyo (Japan). School of Medicine; Soulie, D.; Cordoliani, Y.S.; Iba-Zizen, M.T.; Cabanis, E.A.

    1997-11-01

    Cortical activity during eye movement was examined with functional magnetic resonance imaging. Horizontal saccadic eye movements and smooth pursuit eye movements were elicited in normal subjects. Activity in the frontal eye field was found during both saccadic and smooth pursuit eye movements at the posterior margin of the middle frontal gyrus and in parts of the precentral sulcus and precentral gyrus bordering the middle frontal gyrus (Brodmann`s areas 8, 6, and 9). In addition, activity in the parietal eye field was found in the deep, upper margin of the angular gyrus and of the supramarginal gyrus (Brodmann`s areas 39 and 40) during saccadic eye movement. Activity of V5 was found at the intersection of the ascending limb of the inferior temporal sulcus and the lateral occipital sulcus during smooth pursuit eye movement. Our results suggest that functional magnetic resonance imaging is useful for detecting cortical activity during eye movement. (author)

  2. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

    Baun, Christina; Falch Braas, Kirsten; D. Nielsen, Kamilla

    2015-01-01

    might avoid including the eye in the CT scan without losing sufficient visualization of the scull base. The aim of this study was to evaluate the possibility of decreasing the radiation dose to the eye lens, simply by changing the head position, when doing the PET/CT scan from the base of the scull......Radiation Dose to the Eye Lens: Does Positioning Really Matter? C. Baun1, K. Falch1, K.D. Nielsen2, S. Shanmuganathan1, O. Gerke1, P.F. Høilund-Carlsen1 1Department of Nuclear Medicine, Odense University Hospital, Odense C, Denmark. 2University College Lillebaelt, Odense, Denmark. Aim: The scan...... field in oncology patients undergoing eyes-to-thighs PET/CT must always include the base of the scull according to department guidelines. The eye lens is sensitive to radiation exposure and if possible it should be avoided to scan the eye. If the patient’s head is kipped backwards during the scan one...

  3. Lymphatics and Lymphangiogenesis in the Eye

    Directory of Open Access Journals (Sweden)

    Shintaro Nakao

    2012-01-01

    Full Text Available Lymphatic is a prerequisite for the maintenance of tissue fluid balance and immunity in the body. A body of evidence also shows that lymphangiogenesis plays important roles in the pathogenesis of diseases such as tumor metastasis and inflammation. The eye was thought to lack lymphatic vessels except for the conjunctiva; however, advances in the field, including the identification of lymphatic endothelial markers (e.g., LYVE-1 or podoplanin and lymphangiogenic factors (e.g., VEGF-C, have revealed the exsitence and possible roles of lymphatics and lymphangiogenesis in the eye. Recent studies have shown that corneal limbus, ciliary body, lacrimal gland, orbital meninges, and extraocular muscles contain lymphatic vessels and that the choroid might have a lymphatic-like system. There is no known lymphatic outflow from the eye. However, several lymphatic channels including uveolymphatic pathway might serve the ocular fluid homeostasis. Furthermore, lymphangiogenesis plays important roles in pathological conditions in the eye including corneal transplant rejection and ocular tumor progression. Yet, the role of lymphangiogenesis in most eye diseases, especially inflammatory disease or edema, remains unknown. A better understanding of lymphatic and lymphangiogenesis in the eye will open new therapeutic opportunities to prevent vision loss in ocular diseases.

  4. Modern sports eye injuries.

    Science.gov (United States)

    Capão Filipe, J A; Rocha-Sousa, A; Falcão-Reis, F; Castro-Correia, J

    2003-11-01

    To determine the severity and long term sequelae of eye injuries caused by modern sports that could be responsible for significant ocular trauma in the future. Prospective observational study of 24 (25 eyes) athletes with sports related ocular injuries from health clubs, war games, adventure, radical and new types of soccer, presenting to an eye emergency department between 1992 and 2002 (10 years). Modern sports were responsible for 8.3% of the 288 total sports eye injuries reported. Squash (29.2%) was the most common cause, followed by paintball (20.8%) and motocross (16.6%). The most common diagnosis during the follow up period was retinal breaks (20%). 18 (75%) patients sustained a severe injury. The final visual acuity remained <20/100 in two paintball players. Ocular injuries resulting from modern sports are often severe. Adequate instruction of the participants in the games, proper use of eye protectors, and a routine complete ophthalmological examination after an eye trauma should be mandatory.

  5. Do the Eyes Have It? Using Eye Tracking to Assess Students Cognitive Dimensions

    Science.gov (United States)

    Nisiforou, Efi A.; Laghos, Andrew

    2013-01-01

    Field dependence/independence (FD/FI) is a significant dimension of cognitive styles. The paper presents results of a study that seeks to identify individuals' level of field independence during visual stimulus tasks processing. Specifically, it examined the relationship between the Hidden Figure Test (HFT) scores and the eye tracking metrics.…

  6. Do the Eyes Have It? Using Eye Tracking to Assess Students Cognitive Dimensions

    Science.gov (United States)

    Nisiforou, Efi A.; Laghos, Andrew

    2013-01-01

    Field dependence/independence (FD/FI) is a significant dimension of cognitive styles. The paper presents results of a study that seeks to identify individuals' level of field independence during visual stimulus tasks processing. Specifically, it examined the relationship between the Hidden Figure Test (HFT) scores and the eye tracking metrics.…

  7. Rotational symmetric HMD with eye-tracking capability

    Science.gov (United States)

    Liu, Fangfang; Cheng, Dewen; Wang, Qiwei; Wang, Yongtian

    2016-10-01

    As an important auxiliary function of head-mounted displays (HMDs), eye tracking has an important role in the field of intelligent human-machine interaction. In this paper, an eye-tracking HMD system (ET-HMD) is designed based on the rotational symmetric system. The tracking principle in this paper is based on pupil-corneal reflection. The ET-HMD system comprises three optical paths for virtual display, infrared illumination, and eye tracking. The display optics is shared by three optical paths and consists of four spherical lenses. For the eye-tracking path, an extra imaging lens is added to match the image sensor and achieve eye tracking. The display optics provides users a 40° diagonal FOV with a ״ 0.61 OLED, the 19 mm eye clearance, and 10 mm exit pupil diameter. The eye-tracking path can capture 15 mm × 15 mm of the users' eyes. The average MTF is above 0.1 at 26 lp/mm for the display path, and exceeds 0.2 at 46 lp/mm for the eye-tracking path. Eye illumination is simulated using LightTools with an eye model and an 850 nm near-infrared LED (NIR-LED). The results of the simulation show that the illumination of the NIR-LED can cover the area of the eye model with the display optics that is sufficient for eye tracking. The integrated optical system HMDs with eye-tracking feature can help improve the HMD experience of users.

  8. The effect of cataract on eye movement perimetry

    NARCIS (Netherlands)

    G. Thepass; J.J.M. Pel (Johan); K.A. Vermeer (Koen); O. Creten; S. Bryan (Stirling); H.G. Lemij (Hans); J. van der Steen (Hans)

    2015-01-01

    textabstractPurpose. To determine how different grades of cataract affect sensitivity threshold and saccadic reaction time (SRT) in eye movement perimetry (EMP). Methods. In EMP, the visual field is tested by assessing the saccades that a subject makes towards peripheral stimuli using an eye

  9. Application of 3-dimensional printing technology to construct an eye model for fundus viewing study.

    Directory of Open Access Journals (Sweden)

    Ping Xie

    Full Text Available To construct a life-sized eye model using the three-dimensional (3D printing technology for fundus viewing study of the viewing system.We devised our schematic model eye based on Navarro's eye and redesigned some parameters because of the change of the corneal material and the implantation of intraocular lenses (IOLs. Optical performance of our schematic model eye was compared with Navarro's schematic eye and other two reported physical model eyes using the ZEMAX optical design software. With computer aided design (CAD software, we designed the 3D digital model of the main structure of the physical model eye, which was used for three-dimensional (3D printing. Together with the main printed structure, polymethyl methacrylate(PMMA aspherical cornea, variable iris, and IOLs were assembled to a physical eye model. Angle scale bars were glued from posterior to periphery of the retina. Then we fabricated other three physical models with different states of ammetropia. Optical parameters of these physical eye models were measured to verify the 3D printing accuracy.In on-axis calculations, our schematic model eye possessed similar size of spot diagram compared with Navarro's and Bakaraju's model eye, much smaller than Arianpour's model eye. Moreover, the spherical aberration of our schematic eye was much less than other three model eyes. While in off- axis simulation, it possessed a bit higher coma and similar astigmatism, field curvature and distortion. The MTF curves showed that all the model eyes diminished in resolution with increasing field of view, and the diminished tendency of resolution of our physical eye model was similar to the Navarro's eye. The measured parameters of our eye models with different status of ametropia were in line with the theoretical value.The schematic eye model we designed can well simulate the optical performance of the human eye, and the fabricated physical one can be used as a tool in fundus range viewing research.

  10. Eye movement identification based on accumulated time feature

    Science.gov (United States)

    Guo, Baobao; Wu, Qiang; Sun, Jiande; Yan, Hua

    2017-06-01

    Eye movement is a new kind of feature for biometrical recognition, it has many advantages compared with other features such as fingerprint, face, and iris. It is not only a sort of static characteristics, but also a combination of brain activity and muscle behavior, which makes it effective to prevent spoofing attack. In addition, eye movements can be incorporated with faces, iris and other features recorded from the face region into multimode systems. In this paper, we do an exploring study on eye movement identification based on the eye movement datasets provided by Komogortsev et al. in 2011 with different classification methods. The time of saccade and fixation are extracted from the eye movement data as the eye movement features. Furthermore, the performance analysis was conducted on different classification methods such as the BP, RBF, ELMAN and SVM in order to provide a reference to the future research in this field.

  11. AN INNER STRUGGLE: UNDER WESTERN EYES

    Directory of Open Access Journals (Sweden)

    Hale Yağlıdere

    2013-06-01

    Full Text Available This study aims to shed light on the most significant aspect of the modern man’s inner struggle in Joseph Conrad’s Under Western Eyes. Joseph Conrad is one of the authors of the twentieth century who was influenced by the psychological philosophy and he makes use of this influence in his works deeply. He who synthesizes the inner nature of the modern man, having conflicts himself with the deeper analysis field of the psychology aims to point out the incomprehensible and unsettled inner nature of the modern man in Under Western Eyes.

  12. AN INNER STRUGGLE: UNDER WESTERN EYES

    Directory of Open Access Journals (Sweden)

    Hale Yağlıdere

    2013-07-01

    Full Text Available ABSTRACT This study aims to shed light on the most significant aspect of the modern man’s inner struggle in Joseph Conrad’s Under Western Eyes. Joseph Conrad is one of the authors of the twentieth century who was influenced by the psychological philosophy and he makes use of this influence in his works deeply. He who synthesizes the inner nature of the modern man, having conflicts himself with the deeper analysis field of the psychology aims to point out the incomprehensible and unsettled inner nature of the modern man in Under Western Eyes. Key Words: Alienation, psychology, unconscious, betrayal.

  13. Chinese Oil Giants Eye Canadian Oil Fields

    Institute of Scientific and Technical Information of China (English)

    Miao Bin

    2005-01-01

    @@ SinoCanada, a subsidiary of Sinopec International Petroleum Exploration and Development Corporation, and Canada-based Synenco Energy Inc announced on May 31 that they have inked a series of agreements to launch a joint venture for common development of the oil sand project located in Athabasca region of Northeast Canada's Alberta Province. Based on the agreements, Sinopec will pay 105 million Canadian dollars (US$84 million) for a stake in Canada's Northern Lights oil sands project while Synenco owns the remaining 60 percent share,and will operate the project as the managing partner.

  14. Eye-head coordination in cats.

    Science.gov (United States)

    Guitton, D; Douglas, R M; Volle, M

    1984-12-01

    Gaze is the position of the visual axis in space and is the sum of the eye movement relative to the head plus head movement relative to space. In monkeys, a gaze shift is programmed with a single saccade that will, by itself, take the eye to a target, irrespective of whether the head moves. If the head turns simultaneously, the saccade is correctly reduced in size (to prevent gaze overshoot) by the vestibuloocular reflex (VOR). Cats have an oculomotor range (OMR) of only about +/- 25 degrees, but their field of view extends to about +/- 70 degrees. The use of the monkey's motor strategy to acquire targets lying beyond +/- 25 degrees requires the programming of saccades that cannot be physically made. We have studied, in cats, rapid horizontal gaze shifts to visual targets within and beyond the OMR. Heads were either totally unrestrained or attached to an apparatus that permitted short unexpected perturbations of the head trajectory. Qualitatively, similar rapid gaze shifts of all sizes up to at least 70 degrees could be accomplished with the classic single-eye saccade and a saccade-like head movement. For gaze shifts greater than 30 degrees, this classic pattern frequently was not observed, and gaze shifts were accomplished with a series of rapid eye movements whose time separation decreased, frequently until they blended into each other, as head velocity increased. Between discrete rapid eye movements, gaze continued in constant velocity ramps, controlled by signals added to the VOR-induced compensatory phase that followed a saccade. When the head was braked just prior to its onset in a 10 degrees gaze shift, the eye attained the target. This motor strategy is the same as that reported for monkeys. However, for larger target eccentricities (e.g., 50 degrees), the gaze shift was interrupted by the brake and the average saccade amplitude was 12-15 degrees, well short of the target and the OMR. Gaze shifts were completed by vestibularly driven eye movements when the

  15. Force-length recording of eye muscles during local-anesthesia surgery in 32 strabismus patients

    NARCIS (Netherlands)

    H.J. Simonsz (Huib)

    1994-01-01

    textabstractAbstract. Force-length recordings were made from isolated human eye muscles during strabismus surgery in local, eye-drop anesthesia in 32 adult patients. From each muscle three recordings were made: (1) while the patient looked with the other eye into the field of action of the recorded

  16. Secondary eyes mediate the response to looming objects in jumping spiders (Phidippus audax, Salticidae).

    Science.gov (United States)

    Spano, Lauren; Long, Skye M; Jakob, Elizabeth M

    2012-12-23

    Some species have sensory systems divided into subsystems with morphologically different sense organs that acquire different types of information within the same modality. Jumping spiders (family Salticidae) have eight eyes. Four eyes are directed anteriorly to view objects in front of the spider: a pair of principal eyes track targets with their movable retinae, while the immobile anterior lateral (AL) eyes have a larger field of view and lower resolution. To test whether the principal eyes, the AL eyes, or both together mediate the response to looming stimuli, we presented spiders with a video of a solid black circle that rapidly expanded (loomed) or contracted (receded). Control spiders and spiders with their principal eyes masked were significantly more likely to back away from the looming stimulus than were spiders with their AL eyes masked. Almost no individuals backed away from the receding stimulus. Our results show that the AL eyes alone mediate the loom response to objects anterior to the spider.

  17. Glaucoma: Eye-to-Eye with Dr. Rachel Bishop

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Glaucoma Eye-to-Eye with Dr. Rachel Bishop Past ... nerves are pale and cupped—signs of advanced glaucoma. Yet the patient wasn't aware of any ...

  18. Effectiveness of eye armor during blast loading.

    Science.gov (United States)

    Bailoor, Shantanu; Bhardwaj, Rajneesh; Nguyen, Thao D

    2015-11-01

    Ocular trauma is one of the most common types of combat injuries resulting from the interaction of military personnel with improvised explosive devices. Ocular blast injury mechanisms are complex, and trauma may occur through various injury mechanisms. However, primary blast injuries (PBI) are an important cause of ocular trauma that may go unnoticed and result in significant damage to internal ocular tissues and visual impairment. Further, the effectiveness of commonly employed eye armor, designed for ballistic and laser protection, in lessening the severity of adverse blast overpressures (BOP) is unknown. In this paper, we employed a three-dimensional (3D) fluid-structure interaction computational model for assessing effectiveness of the eye armor during blast loading on human eyes and validated results against free field blast measurements by Bentz and Grimm (2013). Numerical simulations show that the blast waves focused on the ocular region because of reflections from surrounding facial features and resulted in considerable increase in BOP. We evaluated the effectiveness of spectacles and goggles in mitigating the pressure loading using the computational model. Our results corroborate experimental measurements showing that the goggles were more effective than spectacles in mitigating BOP loading on the eye. Numerical results confirmed that the goggles significantly reduced blast wave penetration in the space between the armor and the eyes and provided larger clearance space for blast wave expansion after penetration than the spectacles. The spectacles as well as the goggles were more effective in reducing reflected BOP at higher charge mass because of the larger decrease in dynamic pressures after the impact. The goggles provided greater benefit of reducing the peak pressure than the spectacles for lower charge mass. However, the goggles resulted in moderate, sustained elevated pressure loading on the eye, that became 50-100% larger than the pressure loading

  19. Through the creator's eyes

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre; Lahlou, Saadi

    2012-01-01

    of an adapted Subjective Evidence-Based Ethnography (SEBE). This methodology combines (a) obtaining first person audio-visual recordings of creative action with a miniature video-camera worn at eye-level, (b) accessing the subjective experience of the participant through a confrontation interview based...

  20. The Aging Eye

    Science.gov (United States)

    ... and Tips Watch, Listen, and Learn Social Media ¡Ojo con su visión! ¡Ojo con su visión! Learn About Eye Disease Among Hispanics/Latinos ¡Ojo con su visión! Toolkits Resources Outreach Tools and ...

  1. An eye for inspiration

    Science.gov (United States)

    2009-11-01

    The discovery that the eye of a particular mantis shrimp has an achromatic quarter-waveplate that is superior to modern-day devices could be a source of inspiration to those designing optical components. Nature Photonics spoke to Nicholas Roberts, one of the researchers involved in the study.

  2. About the Eye

    Medline Plus

    Full Text Available ... of Health (NIH), the National Eye Institute’s mission is to “conduct and support research, training, health information ... and what it does. Macula (MACK-yoo-luh) is the small, sensitive area of the retina needed ...

  3. King and Eye

    DEFF Research Database (Denmark)

    Suwannakij, Sing

    devices, most significantly the photographic and the cine cameras, but also encompassing other ocular apparatuses. The images produced through the contraptions were brought together under the royal eye at the apex, which in turn claimed its supremacy over space, time, and the vast and diverse population...

  4. [Eye and the pregnacy].

    Science.gov (United States)

    Dima, Anne Marie

    2012-01-01

    Pregnancy is associated with changes in many organs and systems including the eyes. Sometimes in pregnancy may appear physiological and pathological ocular changes that may be associated with pre-existing problems. In such cases it is very important interdisciplinary collaboration gynecologist, ophthalmologist.

  5. Eyes for Learning

    Science.gov (United States)

    Orfield, Antonia

    2008-01-01

    Vision is the dominant sense, and the eyes are connected with almost every other part of the brain. If the vision system is poorly developed, children trying to learn suffer. Without good up close vision, students are handicapped even if no one knows or suspects it--they may not even know it themselves. Students do not know that the way they see…

  6. About the Eye

    Medline Plus

    Full Text Available ... NIH), the National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and ... carry visual messages from the retina to the brain. Retina (REH-tin-uh) is the light-sensitive ...

  7. About the Eye

    Medline Plus

    Full Text Available ... of Epidemiology and Clinical Applications eyeGENE Research Directors Office Office of the Scientific Director Sheldon S. Miller, Ph.D., ... David M. Schneeweis, Ph.D., Deputy Scientific Director Office of the Clinical Director Brian P. Brooks, M. ...

  8. Disability: recommendations for eye programmes

    Directory of Open Access Journals (Sweden)

    2013-05-01

    Full Text Available In 2012, CBM’s Medical Eye Care Advisory Working Group met in Hyderabad, India to discuss the inclusion of people with disabilities in eye care.As a result of these discussions, recommendations were made.

  9. Unilateral Amblyopia Affects Two Eyes: Fellow Eye Deficits in Amblyopia.

    Science.gov (United States)

    Meier, Kimberly; Giaschi, Deborah

    2017-03-01

    Unilateral amblyopia is a visual disorder that arises after selective disruption of visual input to one eye during critical periods of development. In the clinic, amblyopia is understood as poor visual acuity in an eye that was deprived of pattern vision early in life. By its nature, however, amblyopia has an adverse effect on the development of a binocular visual system and the interactions between signals from two eyes. Visual functions aside from visual acuity are impacted, and many studies have indicated compromised sensitivity in the fellow eye even though it demonstrates normal visual acuity. While these fellow eye deficits have been noted, no overarching theory has been proposed to describe why and under what conditions the fellow eye is impacted by amblyopia. Here, we consider four explanations that may account for decreased fellow eye sensitivity: the fellow eye is adversely impacted by treatment for amblyopia; the maturation of the fellow eye is delayed by amblyopia; fellow eye sensitivity is impacted for visual functions that rely on binocular cortex; and fellow eye deficits reflect an adaptive mechanism that works to equalize the sensitivity of the two eyes. To evaluate these ideas, we describe five visual functions that are commonly reported to be deficient in the amblyopic eye (hyperacuity, contrast sensitivity, spatial integration, global motion, and motion-defined form), and unify the current evidence for fellow eye deficits. Further research targeted at exploring fellow eye deficits in amblyopia will provide us with a broader understanding of normal visual development and how amblyopia impacts the developing visual system.

  10. Pink Eye: What To Do

    Centers for Disease Control (CDC) Podcasts

    2010-10-12

    In this podcast, CDC's Adam Cohen, MD, a pediatrician and parent, discusses conjunctivitis (pink eye), a common eye condition in children and adults. He reviews pink eye causes and treatment, suggestions on when to call or visit a doctor, and practical tips to prevent pink eye from spreading.  Created: 10/12/2010 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 10/13/2010.

  11. Eye-movements During Translation

    DEFF Research Database (Denmark)

    Balling, Laura Winther

    2013-01-01

    Translation process research or TPR, the study of the cognitive processes involved in translation, is a relatively new field characterised by small-scale studies with few participants and variables. However, the translation process is characterised by much variation between different translators......, texts, tasks and languages, and larger-scale investigations are therefore highly desirable. To that end, we have publicly released the CRITT TPR database which currently contains data from 845 translation sessions but is continually extended. The database includes information about the source and target...... texts as well as both eye-tracking and keylogging data. Based on this database, I present a large-scale analysis of gaze on the source text based on 91 translators' translations of six different texts from English into four different target languages. I use mixed-effects modelling to compare from...

  12. Eye-based head gestures

    DEFF Research Database (Denmark)

    Mardanbegi, Diako; Witzner Hansen, Dan; Pederson, Thomas

    2012-01-01

    A novel method for video-based head gesture recognition using eye information by an eye tracker has been proposed. The method uses a combination of gaze and eye movement to infer head gestures. Compared to other gesture-based methods a major advantage of the method is that the user keeps the gaze...

  13. Tips for Buying Sports Eye Protectors

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  14. Checklist for Your Eye Doctor Appointment

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  15. Eye Symptom Questionnaire to Evaluate Anterior Eye Health.

    Science.gov (United States)

    Woodward, Maria A; Valikodath, Nita G; Newman-Casey, Paula Anne; Niziol, Leslie M; Musch, David C; Lee, Paul P

    2017-06-14

    Ophthalmologists assess eye complaints with a careful history and eye examination; however, other types of physicians have limited tools to evaluate anterior segment (AS) eye diseases. We identified the eye symptom questions that providers should ask to help determine the presence and urgency of AS eye diseases. Persons with and without AS disease completed a self-report eye symptom questionnaire (ESQ) based on the National Institutes of Health Toolbox symptom items in an academic center's corneal and comprehensive eye clinics. Gold standard ophthalmic examination determined the presence and urgency of AS disease. The association between reported symptom severity and the probability of AS disease, or urgent AS disease, was evaluated using logistic regression models, and sensitivity and specificity of the ESQ were also calculated. A total of 324 eyes of 162 subjects were included in the study. Of these, AS disease was present in 255 eyes (79%); of which, 111 eyes showed urgent disease. Increasing symptom severity for eye pain (odds ratio [OR]=2.58; P<0.001), glare (OR=2.61; P=0.001), and blurry vision (OR=1.98; P<0.001) were associated with increased odds of AS disease. Increasing symptom severity for eye pain (OR=2.02; P<0.001), eye redness (OR=1.69; P=0.02), and blurry vision (OR=1.41, P=0.01) were associated with increased odds of urgent AS disease. For the primary analysis with mild symptoms considered relevant, the sensitivity of the ESQ to detect AS disease was 83% and to detect urgent AS disease was 92%. Symptoms of eye pain, glare, redness, and blurry vision indicate the presence and urgency of AS disease.

  16. Tutorial on Biostatistics: Linear Regression Analysis of Continuous Correlated Eye Data.

    Science.gov (United States)

    Ying, Gui-Shuang; Maguire, Maureen G; Glynn, Robert; Rosner, Bernard

    2017-04-01

    To describe and demonstrate appropriate linear regression methods for analyzing correlated continuous eye data. We describe several approaches to regression analysis involving both eyes, including mixed effects and marginal models under various covariance structures to account for inter-eye correlation. We demonstrate, with SAS statistical software, applications in a study comparing baseline refractive error between one eye with choroidal neovascularization (CNV) and the unaffected fellow eye, and in a study determining factors associated with visual field in the elderly. When refractive error from both eyes were analyzed with standard linear regression without accounting for inter-eye correlation (adjusting for demographic and ocular covariates), the difference between eyes with CNV and fellow eyes was 0.15 diopters (D; 95% confidence interval, CI -0.03 to 0.32D, p = 0.10). Using a mixed effects model or a marginal model, the estimated difference was the same but with narrower 95% CI (0.01 to 0.28D, p = 0.03). Standard regression for visual field data from both eyes provided biased estimates of standard error (generally underestimated) and smaller p-values, while analysis of the worse eye provided larger p-values than mixed effects models and marginal models. In research involving both eyes, ignoring inter-eye correlation can lead to invalid inferences. Analysis using only right or left eyes is valid, but decreases power. Worse-eye analysis can provide less power and biased estimates of effect. Mixed effects or marginal models using the eye as the unit of analysis should be used to appropriately account for inter-eye correlation and maximize power and precision.

  17. High-resolution eye tracking using V1 neuron activity

    Science.gov (United States)

    McFarland, James M.; Bondy, Adrian G.; Cumming, Bruce G.; Butts, Daniel A.

    2014-01-01

    Studies of high-acuity visual cortical processing have been limited by the inability to track eye position with sufficient accuracy to precisely reconstruct the visual stimulus on the retina. As a result, studies on primary visual cortex (V1) have been performed almost entirely on neurons outside the high-resolution central portion of the visual field (the fovea). Here we describe a procedure for inferring eye position using multi-electrode array recordings from V1 coupled with nonlinear stimulus processing models. We show that this method can be used to infer eye position with one arc-minute accuracy – significantly better than conventional techniques. This allows for analysis of foveal stimulus processing, and provides a means to correct for eye-movement induced biases present even outside the fovea. This method could thus reveal critical insights into the role of eye movements in cortical coding, as well as their contribution to measures of cortical variability. PMID:25197783

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

    Science.gov (United States)

    Spering, Miriam; Carrasco, Marisa

    2015-04-01

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

  19. Dry Eye Syndrome

    Directory of Open Access Journals (Sweden)

    Mohammad-Ali Javadi

    2011-01-01

    Full Text Available Our understanding of keratoconjunctivitis sicca (KCS, also known as dry eye syndrome, has been changed over recent years. Until lately, the condition was thought to be merely due to aqueous tear insufficiency. Today, it is understood that KCS is a multifactorial disorder due to inflammation of the ocular surface and lacrimal gland, neurotrophic deficiency and meibomian gland dysfunction. This change in paradigm has led to the development of new and more effective medications.

  20. Comprehensive eye evaluation algorithm

    Science.gov (United States)

    Agurto, C.; Nemeth, S.; Zamora, G.; Vahtel, M.; Soliz, P.; Barriga, S.

    2016-03-01

    In recent years, several research groups have developed automatic algorithms to detect diabetic retinopathy (DR) in individuals with diabetes (DM), using digital retinal images. Studies have indicated that diabetics have 1.5 times the annual risk of developing primary open angle glaucoma (POAG) as do people without DM. Moreover, DM patients have 1.8 times the risk for age-related macular degeneration (AMD). Although numerous investigators are developing automatic DR detection algorithms, there have been few successful efforts to create an automatic algorithm that can detect other ocular diseases, such as POAG and AMD. Consequently, our aim in the current study was to develop a comprehensive eye evaluation algorithm that not only detects DR in retinal images, but also automatically identifies glaucoma suspects and AMD by integrating other personal medical information with the retinal features. The proposed system is fully automatic and provides the likelihood of each of the three eye disease. The system was evaluated in two datasets of 104 and 88 diabetic cases. For each eye, we used two non-mydriatic digital color fundus photographs (macula and optic disc centered) and, when available, information about age, duration of diabetes, cataracts, hypertension, gender, and laboratory data. Our results show that the combination of multimodal features can increase the AUC by up to 5%, 7%, and 8% in the detection of AMD, DR, and glaucoma respectively. Marked improvement was achieved when laboratory results were combined with retinal image features.

  1. Lagophthalmos in enophthalmic eyes.

    Science.gov (United States)

    Yip, C-C; Gonzalez-Candial, M; Jain, A; Goldberg, R A; McCann, J D

    2005-06-01

    To report a case series of enophthalmic patients with lagophthalmos. A retrospective review of the electronic medical records at a tertiary health care centre of all patients with the diagnoses of "enophthalmos" and "lagophthalmos". Patients who had a history of diseases (such as Graves' orbitopathy), trauma or surgery of the orbit and eyelid were excluded. Enophthalmos was defined as exophthalmometric reading of 14 mm or less in both eyes. Seven patients (14 eyes) with bilateral enophthalmos were found to have concomitant lagophthalmos. All patients had deep superior sulci bilaterally. The upper eyelids were seen to be severely retro-placed behind the superior orbital rim. The extraocular motilities were full with no focal neurological deficit. The orbicularis oculi function was normal with no facial paralysis. The orbits were soft on retropulsion and no facial asymmetry was noted. The mean exophthalmolmetry reading measured 12.6 (SD 1.1) mm. The lagophthalmos varied from 1-5 mm. One patient (one eye) with 3 mm lagophthalmos developed a corneal ulcer and was treated with topical antibiotics and gold weight placement in the upper eyelid. Enophthalmic patients with deep superior sulci and retro-placed upper eyelids may present with lagophthalmos and exposure keratopathy.

  2. Visual-field function in pseudophakia.

    Science.gov (United States)

    Klewin, K M; Radius, R L; Schultz, R O

    1988-08-01

    An automated perimeter (Octopus 2000) was used to examine visual-field function in 52 pseudophakic eyes. Threshold sensitivity was reduced throughout the visual field by from 0.4 to 20.0 decibels from that of threshold sensitivity in age-matched normal eyes. This reduction was comparable to that seen in contact-lens-corrected aphakic eyes.

  3. Peripheral refraction with eye and head rotation with contact lenses.

    Science.gov (United States)

    Lopes-Ferreira, Daniela P; Neves, Helena I F; Faria-Ribeiro, Miguel; Queirós, António; Fernandes, Paulo R B; González-Méijome, José M

    2015-04-01

    To evaluate the impact of eye and head rotation in the measurement of peripheral refraction with an open-field autorefractometer in myopic eyes wearing two different center-distance designs of multifocal contact lenses (MFCLs). Nineteen right eyes from 19 myopic patients (average central M ± SD = -2.67 ± 1.66 D) aged 20-27 years (mean ± SD = 23.2 ± 3.3 years) were evaluated using a Grand-Seiko autorefractometer. Patients were fitted with one multifocal aspheric center-distance contact lens (Biofinity Multifocal D(®)) and with one multi-concentric MFCL (Acuvue Oasys for Presbyopia). Axial and peripheral refraction were evaluated by eye rotation and by head rotation under naked eye condition and with each MFCL fitted randomly and in independent sessions. For the naked eye, refractive pattern (M, J0 and J45) across the central 60° of the horizontal visual field values did not show significant changes measured by rotating the eye or rotating the head (p > 0.05). Similar results were obtained wearing the Biofinity D, for both testing methods, no obtaining significant differences to M, J0 and J45 values (p > 0.05). For Acuvue Oasys for presbyopia, also no differences were found when comparing measurements obtained by eye and head rotation (p > 0.05). Multivariate analysis did not showed a significant interaction between testing method and lens type neither with measuring locations (MANOVA, p > 0.05). There were significant differences in M and J0 values between naked eyes and each MFCL. Measurements of peripheral refraction by rotating the eye or rotating the head in myopic patients wearing dominant design or multi-concentric multifocal silicone hydrogel contact lens are comparable. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  4. Eye gaze estimation from a video

    OpenAIRE

    Merad, Djamel; Mailles-Viard Metz, Stéphanie; Miguet, Serge

    2006-01-01

    International audience; Our work focuses on the interdisciplinary field of detailed analysisof behaviors exhibited by individuals during sessions of distributedcollaboration. With a particular focus on ergonomics, wepropose new mechanisms to be integrated into existing tools toenable increased productivity in distributed learning and working.Our technique is to record ocular movements (eye tracking) to analyzevarious scenarios of distributed collaboration in the contextof computer-based train...

  5. Seeing the future: using Xenopus to understand eye regeneration.

    Science.gov (United States)

    Tseng, Ai-Sun

    2017-01-01

    Studies of Xenopus eye development have contributed considerably to the understanding of vertebrate neurogenesis, including eye field specification, cell fate determination and identification of genes critical for eye formation. This knowledge has served as a solid foundation for cellular and molecular examinations of the robust regenerative capacity of the Xenopus eye. The retina, lens, and the optic nerve are capable of regeneration after injury in both larval and adult stages. Here, we discuss the current models for studying eye regeneration in Xenopus and their potential applications for providing insights into human eye diseases. As Xenopus has many of the same tools that are available for other regeneration models, we thus highlight the distinct strengths and versatility of this organism that make it especially suited for extrapolating and testing strategies aimed at promoting regeneration and repair in eye tissues. Furthermore, we outline a promising future for the use of new techniques and approaches to address outstanding questions in understanding eye regeneration. © 2017 Wiley Periodicals, Inc.

  6. Ethical Issues in Transnational Eye Banking.

    Science.gov (United States)

    Martin, Dominique E; Kelly, Richard; Jones, Gary L A; Machin, Heather; Pollock, Graeme A

    2017-02-01

    To review ethical issues that may arise in the setting of transnational eye banking activities, such as when exporting or importing corneal tissue for transplantation. A principle-based normative analysis of potential common dilemmas in transnational eye banking activities was performed. Transnational activities in eye banking, like those in other fields involving procurement and use of medical products of human origin, may present a number of ethical issues for policy makers and professionals. Key ethical concerns include the potential impact of export or import activities on self-sufficiency of corneal tissue supply within exporting and importing countries; potential disclosure requirements when obtaining consent or authorization for ocular tissue donation when donations may be exported; and difficulties inherent in assuring equity in the allocation of tissues available for export and in establishing and respecting standards of safety and quality across different jurisdictions. Further analysis of specific ethical issues in eye banking is necessary to inform development of guidelines and other governance tools that will assist policy makers and professionals to support ethical practice.

  7. The "hypnotic state" and eye movements: Less there than meets the eye?

    Science.gov (United States)

    Nordhjem, Barbara; Marcusson-Clavertz, David; Holmqvist, Kenneth

    2017-01-01

    Responsiveness to hypnotic procedures has been related to unusual eye behaviors for centuries. Kallio and collaborators claimed recently that they had found a reliable index for "the hypnotic state" through eye-tracking methods. Whether or not hypnotic responding involves a special state of consciousness has been part of a contentious debate in the field, so the potential validity of their claim would constitute a landmark. However, their conclusion was based on 1 highly hypnotizable individual compared with 14 controls who were not measured on hypnotizability. We sought to replicate their results with a sample screened for High (n = 16) or Low (n = 13) hypnotizability. We used a factorial 2 (high vs. low hypnotizability) x 2 (hypnosis vs. resting conditions) counterbalanced order design with these eye-tracking tasks: Fixation, Saccade, Optokinetic nystagmus (OKN), Smooth pursuit, and Antisaccade (the first three tasks has been used in Kallio et al.'s experiment). Highs reported being more deeply in hypnosis than Lows but only in the hypnotic condition, as expected. There were no significant main or interaction effects for the Fixation, OKN, or Smooth pursuit tasks. For the Saccade task both Highs and Lows had smaller saccades during hypnosis, and in the Antisaccade task both groups had slower Antisaccades during hypnosis. Although a couple of results suggest that a hypnotic condition may produce reduced eye motility, the lack of significant interactions (e.g., showing only Highs expressing a particular eye behavior during hypnosis) does not support the claim that eye behaviors (at least as measured with the techniques used) are an indicator of a "hypnotic state.” Our results do not preclude the possibility that in a more spontaneous or different setting the experience of being hypnotized might relate to specific eye behaviors. PMID:28846696

  8. Wave-front analysis of personal eye protection.

    Science.gov (United States)

    Eppig, Timo; Zoric, Katja; Speck, Alexis; Zelzer, Benedikt; Götzelmann, Jens; Nagengast, Dieter; Langenbucher, Achim

    2012-07-30

    Shack-Hartmann wave-front sensing has been successfully applied to many fields of optical testing including the human eye itself. We propose wave-front measurement for testing protective eye wear for production control and investigation of aberrations. Refractive power data is derived from the wave-front data and compared to a subjective measurement technique based on a focimeter. Additional image quality classification was performed with a multivariate model using objective parameters to resample a subjectively determined visual quality. Wave-front measurement advances optical testing of protective eye wear and may be used for objective quality control.

  9. Through Einstein's Eyes

    CERN Document Server

    Searle, A C; Altin, P A; Bennet, F H; Hush, M R; Searle, Antony C.; Savage, Craig M.; Altin, Paul A.; Bennet, Francis H.; Hush, Michael R.

    2005-01-01

    We have developed a relativistically-accurate computer graphics code and have used it to produce photo-realistic images and videos of scenes where special relativistic effects dominate, either in astrophysical contexts or in imaginary worlds where the speed of light is only a few metres per second. The videos have been integrated into our under-graduate teaching programme for several years. Recently we took the next step, encouraging undergraduate students to use the code to explore relativity, develop their own videos, and eventually package them together into Through Einstein's Eyes, a multimedia CD.

  10. Eye trauma in boxing.

    Science.gov (United States)

    Corrales, Gustavo; Curreri, Anthony

    2009-10-01

    In boxing, along with a few other sports, trauma is inherent to the nature of the sport; therefore it is considered a high-risk sport for ocular injuries. The long-term morbidity of ocular injuries suffered by boxers is difficult to estimate due to the lack of structured long-term follow-up of these athletes. Complications of blunt ocular trauma may develop years after the athlete has retired from the ring and is no longer considered to be at risk for boxing-related injuries. This article describes the wide range of eye injuries a boxer can sustain, and their immediate and long-term clinical management.

  11. Endoscopic Application of a Compact Compound-Eye Camera

    Directory of Open Access Journals (Sweden)

    Keiichiro Kagawa

    2015-02-01

    Full Text Available A multi-functional compound-eye endoscope enabling multi-spectral imaging and variable field-of-view is presented, which is based on a compact compound-eye camera called TOMBO (thin observation module by bound optics. Narrow-band filters attached to some lenses provide snap-shot multi-band images. Fixed and movable mirrors are introduced to control the field of view, which realizes several observation modes such as three-dimensional shape measurement, wide field-of-view, and close-up observation.

  12. Endoscopic Application of a Compact Compound-Eye Camera

    OpenAIRE

    Keiichiro Kagawa; Shoji Kawahito

    2015-01-01

    A multi-functional compound-eye endoscope enabling multi-spectral imaging and variable field-of-view is presented, which is based on a compact compound-eye camera called TOMBO (thin observation module by bound optics). Narrow-band filters attached to some lenses provide snap-shot multi-band images. Fixed and movable mirrors are introduced to control the field of view, which realizes several observation modes such as three-dimensional shape measurement, wide field-of-view, and close-up observa...

  13. A Seeing-eye Dog

    Institute of Scientific and Technical Information of China (English)

    范图雨

    2000-01-01

    A seeing-eye dog is a special(特殊的) dog. It helps blind people walk along the streets and do many other things. We call these dogs ""seeing-eye"" dogs because the dogs are the ""eyes"" of the blind man and they help him to ""see"". These dogs go to special schools for several years to learn to help blind people.

  14. Reading between eye saccades.

    Directory of Open Access Journals (Sweden)

    Caroline Blais

    Full Text Available BACKGROUND: Skilled adult readers, in contrast to beginners, show no or little increase in reading latencies as a function of the number of letters in words up to seven letters. The information extraction strategy underlying such efficiency in word identification is still largely unknown, and methods that allow tracking of the letter information extraction through time between eye saccades are needed to fully address this question. METHODOLOGY/PRINCIPAL FINDINGS: The present study examined the use of letter information during reading, by means of the Bubbles technique. Ten participants each read 5,000 five-letter French words sampled in space-time within a 200 ms window. On the temporal dimension, our results show that two moments are especially important during the information extraction process. On the spatial dimension, we found a bias for the upper half of words. We also show for the first time that letter positions four, one, and three are particularly important for the identification of five-letter words. CONCLUSIONS/SIGNIFICANCE: Our findings are consistent with either a partially parallel reading strategy or an optimal serial reading strategy. We show using computer simulations that this serial reading strategy predicts an absence of a word-length effect for words from four- to seven letters in length. We believe that the Bubbles technique will play an important role in further examining the nature of reading between eye saccades.

  15. Eye in pregnancy

    Directory of Open Access Journals (Sweden)

    Achyut N. Pandey

    2014-02-01

    Full Text Available Hormonal, metabolic, hemodynamic, vascular and immunological changes that occur during pregnancy can affect the function of the eye. These changes are commonly transient, but in some cases they may be permanent and have consequences even after childbirth. The ocular effects of pregnancy may be physiological or pathological and can be associated with the development of new ocular pathology or may be modifications of pre-existing conditions. The most common physiological changes are alterations of corneal sensitivity and thickness, decreased tolerance to contact lenses, decreased intraocular pressure, hemeralopia and refractive errors. Possible posterior segment changes include worsening of diabetic retinopathy, central serous chorioretinopathy, increased risk of peripheral vitreochorioretinal dystrophies and retinal detachment. Thus, it should be kept in mind that the presence of any ocular symptoms in a pregnant woman requires ophthalmologic examination and further management. Knowledge of these ocular changes can help to differentiate the physiological changes from ocular manifestation of systemic disease and diseases pertaining to the eye in a pregnant woman. This article explains the effects of ocular changes in pregnancy. [Int J Res Med Sci 2014; 2(1.000: 16-20

  16. Stability of binocular depth perception with moving head and eyes

    NARCIS (Netherlands)

    Ee, R. van; Erkelens, Casper J.

    2001-01-01

    We systematically analyse the binocular disparity field under various eye, head and stimulus positions and orientations. From the literature we know that certain classes of disparity which involve the entire disparity field (such as those caused by horizontal lateral shift, differential rotation, ho

  17. Amblyopia: What Is the Cause of Lazy Eye?

    Science.gov (United States)

    ... Stories Español Eye Health / Eye Health A-Z Amblyopia Sections Amblyopia: What Is Lazy Eye? Amblyopia: What ... Amblyopia: Lazy Eye Diagnosis Amblyopia: Lazy Eye Treatment Amblyopia: What Is the Cause of Lazy Eye? Leer ...

  18. Inter-eye comparison of retinal oximetry and vessel caliber between eyes with asymmetrical glaucoma severity in different glaucoma subtypes

    Directory of Open Access Journals (Sweden)

    Cheng CS

    2016-07-01

    Full Text Available Clarissa Shu Ming Cheng,1,2 Yi Fang Lee,2 Charles Ong,3 Zhu Li Yap,2 Andrew Tsai,2 Aditi Mohla,2 Monisha E Nongpiur,4 Tin Aung,2,4 Shamira A Perera2,4 1Department of Ophthalmology, Tan Tock Seng Hospital, 2Department of Ophthalmology, Singapore National Eye Centre, 3Yong Loo Lin School of Medicine, National University of Singapore, 4Singapore Eye Research Institute, Singapore National Eye Centre, Singapore Background: To compare retinal vessel oxygenation and vessel caliber in primary angle-closure glaucoma (PACG, primary open-angle glaucoma (POAG, normal-tension glaucoma (NTG, and normal controls, as well as between eyes of asymmetrical glaucoma severity.Methods: This was a prospective, cross-sectional study. The 159 subjects (PACG, n=39; POAG, n=41; NTG, n=41; normal controls, n=38 underwent retinal oxygen saturation measurements using the Oxymap T1 Retinal Oximeter, optical coherence tomography, and Humphrey visual field testing. Retinal oxygen saturation and vessel diameter were compared between the glaucoma groups and normal controls, as well as between eyes of asymmetrical glaucoma severity. Kruskal–Wallis test was performed for comparison among different subtypes of glaucoma. Wilcoxon signed-rank test was used to compare the inter-eye differences.Results: Compared to normal controls, arteriolar oxygen saturation was increased in PACG eyes (P=0.048 but not in POAG or NTG eyes. There were no significant differences in oxygen saturation in venules or arteriovenous (AV difference in all three glaucoma groups. Venular diameter was significantly reduced in all glaucoma groups compared to normal controls (P<0.001, but no such change was observed in arteriolar diameter (P=0.10. When comparing between eyes of asymmetrical glaucoma severity, arteriolar oxygen saturation (P=0.03 and AV difference (P=0.04 were significantly higher, while arteriolar diameter was significantly lower (P=0.001 in the worse eye in PACG group. There were no significant

  19. Using Eye Tracking to Assess Reading Performance in Patients with Glaucoma: A Within-Person Study

    Directory of Open Access Journals (Sweden)

    Nicholas D. Smith

    2014-01-01

    Full Text Available Reading is often cited as a demanding task for patients with glaucomatous visual field (VF loss, yet reading speed varies widely between patients and does not appear to be predicted by standard visual function measures. This within-person study aimed to investigate reading duration and eye movements when reading short passages of text in a patient’s worse eye (most VF damage when compared to their better eye (least VF damage. Reading duration and saccade rate were significantly different on average in the worse eye when compared to the better eye (P<0.001 in 14 patients with glaucoma that had median (interquartile range between-eye difference in mean deviation (MD; a standard clinical measure for VF loss of 9.8 (8.3 to 14.8 dB; differences were not related to the size of the difference in MD between eyes. Patients with a more pronounced effect of longer reading duration on their worse eye made a larger proportion of “regressions” (backward saccades and “unknown” EMs (not adhering to expected reading patterns when reading with the worse eye when compared to the better eye. A between-eye study in patients with asymmetric disease, coupled with eye tracking, provides a useful experimental design for exploring reading performance in glaucoma.

  20. Eye tracking and nutrition label use

    DEFF Research Database (Denmark)

    Graham, Dan J.; Orquin, Jacob Lund; Visschers, Vivianne H.M.

    2012-01-01

    Nutrition labels on food packages are among the most prominent and far-reaching policy measures related to diet and have the capacity to promote healthy eating. Unfortunately, certain nutrition label characteristics may impede consumer detection and comprehension of labels. Research using precise...... cameras monitoring consumer visual attention (i.e., eye tracking) has begun to identify ways in which label design could be modified to improve consumers’ ability to locate and effectively utilize nutrition information. The present paper reviews all published studies of nutrition label use that have...... utilized eye tracking methodology, identifies directions for further research in this growing field, and makes research-based recommendations for ways in which labels could be modified to improve consumers’ ability to use nutrition labels to select healthful foods....

  1. Dry Eye as a Mucosal Autoimmune Disease

    Science.gov (United States)

    Stern, Michael E.; Schaumburg, Chris S.; Pflugfelder, Stephen C.

    2013-01-01

    Dry eye is a common ocular surface inflammatory disease that significantly affects quality of life. Dysfunction of the lacrimal function unit (LFU) alters tear composition and breaks ocular surface homeostasis, facilitating chronic inflammation and tissue damage. Accordingly, the most effective treatments to date are geared towards reducing inflammation and restoring normal tear film. The pathogenic role of CD4+ T cells is well known, and the field is rapidly realizing the complexity of other innate and adaptive immune factors involved in the development and progression of disease. The data support the hypothesis that dry eye is a localized autoimmune disease originating from an imbalance in the protective immunoregulatory and proinflammatory pathways of the ocular surface. PMID:23360156

  2. Retinal Laser Burn Disrupts Immune Privilege in the Eye

    Science.gov (United States)

    Qiao, Hong; Lucas, Kenyatta; Stein-Streilein, Joan

    2009-01-01

    Immune privilege allows for the immune protection of the eye in the absence of inflammation. Very few events are capable of overcoming the immune-privileged mechanisms in the eye. In this study, we report that retinal laser burn (RLB) abrogates immune privilege in both the burned and nonburned eye. As early as 6 hours after RLB, and as late as 56 days after RLB, antigen inoculation into the anterior chamber of the burned eye failed to induce peripheral tolerance. After RLB, aqueous humor samples harvested from nontreated eyes but not from either the burned or the contralateral eye, down-regulated the expression of CD40 and up-regulated interleukin-10 mRNA in peritoneal exudate cells, and converted peritoneal exudate cells into tolerogenic antigen-presenting cells (APCs). Unlike F4/80+ APCs from nontreated mice, F4/80+ APCs from RLB mice were unable to transfer tolerance after anterior chamber inoculation of antigen into naïve mice. The increased use of lasers in both the industrial and medical fields raises the risk of RLB-associated loss of immune regulation and an increased risk of immune inflammation in the eye. PMID:19147817

  3. Fixational eye movements in the earliest stage of metazoan evolution.

    Directory of Open Access Journals (Sweden)

    Jan Bielecki

    Full Text Available All known photoreceptor cells adapt to constant light stimuli, fading the retinal image when exposed to an immobile visual scene. Counter strategies are therefore necessary to prevent blindness, and in mammals this is accomplished by fixational eye movements. Cubomedusae occupy a key position for understanding the evolution of complex visual systems and their eyes are assumedly subject to the same adaptive problems as the vertebrate eye, but lack motor control of their visual system. The morphology of the visual system of cubomedusae ensures a constant orientation of the eyes and a clear division of the visual field, but thereby also a constant retinal image when exposed to stationary visual scenes. Here we show that bell contractions used for swimming in the medusae refresh the retinal image in the upper lens eye of Tripedalia cystophora. This strongly suggests that strategies comparable to fixational eye movements have evolved at the earliest metazoan stage to compensate for the intrinsic property of the photoreceptors. Since the timing and amplitude of the rhopalial movements concur with the spatial and temporal resolution of the eye it circumvents the need for post processing in the central nervous system to remove image blur.

  4. [A correct understanding of preservatives in eye drops].

    Science.gov (United States)

    Liu, Zuguo; Huang, Caihong

    2015-09-01

    Eye drops are the most commonly used preparations in ophthalmology. Preservatives are usually added in order to protect eye drops against pathogenic organisms and increase the solubility of the drugs in multi-dose containers. Ophthalmologists have paid a lot of attention to the preservatives in eye drops because they remain one of the main reasons for ocular surface damage, and even may lead to serious visual impairment in patients with inappropriate use of eye drops. However, it should be noted that the dangers of preservatives become overstated nowadays. It is necessary to completely evaluate the effects of preservatives in ophthalmic preparations, so that ophthalmologists can guide patients to correctly select eye drops containing preservatives and avoid dangerous side effects, according to their eye disease situation, state of tear function and ocular surface changes, cultural background and financial income, cost and benefit and convenience of the use of drugs, and other factors. The direction of the future development in this field is to establish the clinical guideline for use of eye drops containing preservatives, carry out continuing education courses on preservatives and develop ideal preservatives.

  5. Choosing Wisely When It Comes to Eye Care: Antibiotics for Eye Injections

    Science.gov (United States)

    ... Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask an ... healthy lifestyle choices can help you protect your vision by reducing your risk for eye diseases , eye infections and eye injuries . Partnering with your ...

  6. Choosing Wisely When It Comes to Eye Care: Antibiotics for Pink Eye

    Science.gov (United States)

    ... Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask an ... healthy lifestyle choices can help you protect your vision by reducing your risk for eye diseases , eye infections and eye injuries . Partnering with your ...

  7. Choosing Wisely When It Comes to Eye Care: Punctal Plugs for Dry Eye

    Science.gov (United States)

    ... Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask an ... healthy lifestyle choices can help you protect your vision by reducing your risk for eye diseases, eye infections and eye injuries . Partnering with your ...

  8. Danish Rural Eye Study

    DEFF Research Database (Denmark)

    Høeg, Tracy B; Moldow, Birgitte; Ellervik, Christina

    2015-01-01

    PURPOSE: To determine the prevalence of amblyopia in Denmark before and after the initiation of the Danish national preschool vision screening programme. METHODS: In a population-based cross-sectional study, 3826 participants of the Danish General Suburban Population Study (GESUS) aged 20 years...... 45-degree retinal fundus photographs of each eye. A complete ophthalmologic examination was performed when indicated. RESULTS: The prevalence of monocular visual impairment (MVI) was 4.26% (95% CI, 3.66-4.95, n = 163). Amblyopia was the most common cause, accounting for 33%. The prevalence...... of amblyopia was 1.44% (95% CI, 1.01-1.81, n = 55), being higher among non-preschool vision screened persons compared to those who were offered (estimated 95% attendance) preschool vision screening (1.78%, n = 41, 95% CI 1.24-2.33 versus 0.44%, n = 2, 95% CI, 0.12-1.60, p = 0.024). The leading cause...

  9. The Colossal Cosmic Eye

    Science.gov (United States)

    2005-09-01

    Eighty-five million years ago on small planet Earth, dinosaurs ruled, ignorant of their soon-to-come demise in the great Jurassic extinction, while mammals were still small and shy creatures. The southern Andes of Bolivia, Chile, and Argentina were not yet formed and South America was still an island continent. Eighty-five million years ago, our Sun and its solar system was 60,000 light years away from where it now stands [1]. Eighty-five million years ago, in another corner of the Universe, light left the beautiful spiral galaxy NGC 1350, for a journey across the universe. Part of this light was recorded at the beginning of the year 2000 AD by ESO's Very Large Telescope, located on the 2,600m high Cerro Paranal in the Chilean Andes on planet Earth. Astronomers classify NGC 1350 as an Sa(r) type galaxy, meaning it is a spiral with large central regions. In fact, NGC 1350 lies at the border between the broken-ring spiral type and a grand design spiral with two major outer arms. It is about 130,000 light-years across and, hence, is slightly larger than our Milky Way. The rather faint and graceful outer arms originate at the inner main ring and can be traced for almost half a circle when they each meet the opposite arm, giving the impression of completing a second outer ring, the "eye". The arms are given a blue tint as a result of the presence of very young and massive stars. The amount of dust, seen as small fragmented dust spirals in the central part of the galaxy and producing a fine tapestry that bear resemblance with blood vessels in the eye, is also a signature of the formation of stars.

  10. Eye Movements in Gaze Interaction

    DEFF Research Database (Denmark)

    Møllenbach, Emilie; Hansen, John Paulin; Lillholm, Martin

    2013-01-01

    Gaze as a sole input modality must support complex navigation and selection tasks. Gaze interaction combines specific eye movements and graphic display objects (GDOs). This paper suggests a unifying taxonomy of gaze interaction principles. The taxonomy deals with three types of eye movements: fix...

  11. Childhood Eye Diseases and Conditions

    Science.gov (United States)

    ... have a fever. More serious preseptal or orbital cellulitis infections can cause decreased vision, an inability to move the eye, and the appearance of the eye being pushed forward. What to do: Both forms of cellulitis are serious conditions that require urgent medical attention. ...

  12. Compensatory eye movements in mice

    NARCIS (Netherlands)

    A.M. van Alphen (Adriaan)

    2002-01-01

    textabstractThis thesis will address the generation of compensatory eye movements in naturally mutated or genetically modified mice. The reason for generating compensatory eye movements is solely related to the requirements for good vision. In a subject moving through its environment the projection

  13. Eye tracking for visual marketing

    NARCIS (Netherlands)

    Wedel, M.; Pieters, R.

    2008-01-01

    We provide the theory of visual attention and eye-movements that serves as a basis for evaluating eye-tracking research and for discussing salient and emerging issues in visual marketing. Motivated from its rising importance in marketing practice and its potential for theoretical contribution, we

  14. Conjunctivitis (Pink Eye) in Newborns

    Science.gov (United States)

    ... Work Adenovirus Non-Polio Enterovirus Parent Portal Conjunctivitis (Pink Eye) in Newborns Language: English Español (Spanish) Recommend ... recién nacidos Newborns with symptoms of conjunctivitis (pink eye) should see a doctor right away. Neonatal ...

  15. Eye Movements in Gaze Interaction

    DEFF Research Database (Denmark)

    Møllenbach, Emilie; Hansen, John Paulin; Lillholm, Martin

    2013-01-01

    Gaze as a sole input modality must support complex navigation and selection tasks. Gaze interaction combines specific eye movements and graphic display objects (GDOs). This paper suggests a unifying taxonomy of gaze interaction principles. The taxonomy deals with three types of eye movements...

  16. A wide angle low coherence interferometry based eye length optometer

    Science.gov (United States)

    Meadway, Alexander; Siegwart, John; Wildsoet, Christine; Norton, Thomas; Zhang, Yuhua

    2015-03-01

    Interest in eye growth regulation has burgeoned with the rise in myopia prevalence world-wide. Eye length and eye shape are fundamental metrics for related research, but current in vivo measurement techniques are generally limited to the optical axis of the eye. We describe a high resolution, time domain low coherence interferometry based optometer for measuring the eye length of small animals over a wide field of view. The system is based upon a Michelson interferometer using a superluminescent diode as a source, including a sample arm and a reference arm. The sample arm is split into two paths by a polarisation beam splitter; one focuses the light on the cornea and the other focuses the light on the retina. This method has a high efficiency of detection for reflections from both surfaces. The reference arm contains a custom high speed linear motor with 25 mm stroke and equipped with a precision displacement encoder. Light reflected from the cornea and the retina is combined with the reference beam to generate low coherence interferograms. Two galvo scanners are employed to steer the light to different angles so that the eye length over a field of view of 20° × 20° can be measured. The system has an axial resolution of 6.8 μm (in air) and the motor provides accurate movement, allowing for precise and repeatable measurement of coherence peak positions. Example scans from a tree shrew are presented.

  17. Monitoring the eye lens: which dose quantity is adequate?

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, R [Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig (Germany); Dietze, G, E-mail: rolf.behrens@ptb.d [Paracelsusstrasse 7, D-38116 Braunschweig (Germany)

    2010-07-21

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. The question of which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens arises from this situation. While in many countries dosemeters calibrated in terms of the dose equivalent quantity H{sub p}(0.07) have been seen as being adequate for monitoring the dose to the eye lens, this might be questionable in the case of reduced dose limits and, thus, it may become necessary to use the dose equivalent quantity H{sub p}(3) for this purpose. To discuss this question, the dose conversion coefficients for the equivalent dose of the eye lens (in the following eye lens dose) were determined for realistic photon and beta radiation fields and compared with the values of the corresponding conversion coefficients for the different operational quantities. The values obtained lead to the following conclusions: in radiation fields where most of the dose comes from photons, especially x-rays, it is appropriate to use dosemeters calibrated in terms of H{sub p}(0.07) on a slab phantom, while in other radiation fields (dominated by beta radiation or unknown contributions of photon and beta radiation) dosemeters calibrated in terms of H{sub p}(3) on a slab phantom should be used. As an alternative, dosemeters calibrated in terms of H{sub p}(0.07) on a slab phantom could also be used; however, in radiation fields containing beta radiation with the end point energy near 1 MeV, an overestimation of the eye lens dose by up to a factor of 550 is possible.

  18. Invited Article: First Flight in Space of a Wide-field-of-view Soft X-Ray Imager Using Lobster-Eye Optics: Instrument Description and Initial Flight Results

    Science.gov (United States)

    Collier, Michael; Porter, F. Scott; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chomay, Dennis J.; Cravens, Thomas E.; Galeazzi, Massiniliano; Keller, John; Koutroumpa, Dimitra

    2015-01-01

    We describe the development, launch into space, and initial results from a prototype wide eld-of-view (FOV) soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The Sheath Transport Observer for the Redistribution of Mass (STORM) is the rst instrument using this type of optics launched into space and provides proof-of-concept for future ight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the moon, and the solar wind interaction with planetary bodies like Venus and Mars.

  19. Invited Article: First Flight in Space of a Wide-field-of-view Soft X-Ray Imager Using Lobster-Eye Optics: Instrument Description and Initial Flight Results

    Science.gov (United States)

    Collier, Michael; Porter, F. Scott; Sibeck, David G.; Carter, Jenny A.; Chiao, Meng P.; Chomay, Dennis J.; Cravens, Thomas E.; Galeazzi, Massiniliano; Keller, John; Koutroumpa, Dimitra

    2015-01-01

    We describe the development, launch into space, and initial results from a prototype wide eld-of-view (FOV) soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The Sheath Transport Observer for the Redistribution of Mass (STORM) is the rst instrument using this type of optics launched into space and provides proof-of-concept for future ight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the moon, and the solar wind interaction with planetary bodies like Venus and Mars.

  20. Efficient Avoidance of the Penalty Zone in Human Eye Movements

    Science.gov (United States)

    Theeuwes, Jan

    2016-01-01

    People use eye movements extremely effectively to find objects of interest in a cluttered visual scene. Distracting, task-irrelevant attention capturing regions in the visual field should be avoided as they jeopardize the efficiency of search. In the current study, we used eye tracking to determine whether people are able to avoid making saccades to a predetermined visual area associated with a financial penalty, while making fast and accurate saccades towards stimuli placed near the penalty area. We found that in comparison to the same task without a penalty area, the introduction of a penalty area immediately affected eye movement behaviour: the proportion of saccades to the penalty area was immediately reduced. Also, saccadic latencies increased, but quite modestly, and mainly for saccades towards stimuli near the penalty area. We conclude that eye movement behaviour is under efficient cognitive control and thus quite flexible: it can immediately be adapted to changing environmental conditions to improve reward outcome. PMID:27930724

  1. The central retinal artery occlusion in the right eye followed by a branch retinal artery occlusion in the left eye four days later

    Directory of Open Access Journals (Sweden)

    Cagatay Caglar

    2013-01-01

    Full Text Available A 65-year-old woman was admitted to our clinic with complaints of sudden, painless, decrease in vision, and sectoral visual field defect in the left eye and later presented to our clinic again with a history of sudden loss of vision in her right eye. In this case study we reported that the patient had branch retinal artery occlusion (BRAO in the left eye and at the same time progressing central retinal artery occlusion (CRAO in the right eye.

  2. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Patient Stories Español Eye Health / Tips & Prevention Your Eyes and the Sun Sections The Sun, UV Radiation ... Safety Infographic The Sun, UV Radiation and Your Eyes Written by: David Turbert Aug. 28, 2014 Keep ...

  3. Dry Eyes and Glaucoma: Double Trouble

    Science.gov (United States)

    ... News About Us Donate In This Section Dry Eyes and Glaucoma: Double Trouble email Send this article ... disease bothers the patient more. What Causes Dry Eye Syndrome? Dry eye can be caused by many ...

  4. 21 CFR 886.3200 - Artificial eye.

    Science.gov (United States)

    2010-04-01

    ... OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a... inserted in a patient's eye socket anterior to an orbital implant, or the eviscerated eyeball, for...

  5. Chance and necessity in eye evolution

    National Research Council Canada - National Science Library

    Gehring, Walter J

    2011-01-01

    ...." Recent discoveries in eye evolution are in agreement with both of these theses. They confirm Darwin's assumption of a simple eye prototype and lend strong support for the notion of a monophyletic origin of the various eye types...

  6. Edge Detection Model Based on Involuntary Eye Movements of the Eye-Retina System

    Directory of Open Access Journals (Sweden)

    András Róka

    2007-03-01

    Full Text Available Traditional edge-detection algorithms in image processing typically convolute afilter operator and the input image, and then map overlapping input image regions tooutput signals. Convolution also serves as a basis in biologically inspired (Sobel, Laplace,Canny algorithms. Recent results in cognitive retinal research have shown that ganglioncell receptive fields cover the mammalian retina in a mosaic arrangement, withinsignificant amounts of overlap in the central fovea. This means that the biologicalrelevance of traditional and widely adapted edge-detection algorithms with convolutionbasedoverlapping operator architectures has been disproved. However, using traditionalfilters with non-overlapping operator architectures leads to considerable losses in contourinformation. This paper introduces a novel, tremor-based retina model and edge-detectionalgorithm that reconciles these differences between the physiology of the retina and theoverlapping architectures used by today's widely adapted algorithms. The algorithm takesinto consideration data convergence, as well as the dynamic properties of the retina, byincorporating a model of involuntary eye tremors and the impulse responses of ganglioncells. Based on the evaluation of the model, two hypotheses are formulated on the highlydebated role of involuntary eye tremors: 1 The role of involuntary eye tremors hasinformation theoretical implications 2 From an information processing point of view, thefunctional role of involuntary eye-movements extends to more than just the maintenance ofaction potentials. Involuntary eye-movements may be responsible for the compensation ofinformation losses caused by a non-overlapping receptive field architecture. In support ofthese hypotheses, the article provides a detailed analysis of the model's biologicalrelevance, along with numerical simulations and a hardware implementation.

  7. Evaluation of peripheral fundus autofluorescence in eyes with wet age-related macular degeneration

    Directory of Open Access Journals (Sweden)

    Suetsugu T

    2016-12-01

    Full Text Available Tetsuyuki Suetsugu,1,2 Aki Kato,1 Munenori Yoshida,1 Tsutomu Yasukawa,1 Akiko Nishiwaki,1,3 Norio Hasegawa,1 Hideaki Usui,1 Yuichiro Ogura1 1Department of Ophthalmology and Visual Science, Nagoya City University Graduate School of Medical Sciences, 2Department of Ophthalmology, General Kamiiida Daiichi Hospital, 3Nishiwaki Eye Clinic, Nagoya, Aichi, Japan Purpose: We aimed to evaluate the prevalence of abnormal peripheral fundus autofluorescence (FAF in wet age-related macular degeneration (AMD using wide-field imaging instrument. Patients and methods: A retrospective, case-controlled study involving 66 eyes of 46 Japanese wet AMD patients and 32 eyes of 20 control patients was performed. Wide-field FAF images were obtained for typical AMD (37 eyes/28 patients, polypoidal choroidal vasculopathy (PCV (22 eyes/20 patients, and retinal angiomatous proliferation (RAP (seven eyes/four patients. Two masked ophthalmologists independently graded the images for mottled, granular, and nummular patterns. Main outcome measures were abnormal peripheral FAF frequencies and relative risks by disease subgroups and treatments. Results: Abnormal peripheral FAF patterns were found in 51.5% of wet AMD eyes compared with 18.8% of control eyes (P<0.001. Mottled, granular, and nummular patterns were found in 45.5%, 31.8%, and 16.7%, respectively, of wet AMD eyes. Each disease subgroup (typical AMD, 54.1%; PCV, 36.4%; and RAP, 85.7% showed significantly higher frequencies of peripheral FAF (P<0.001, P=0.03, and P<0.001, respectively than control eyes (18.8%. There were no significant differences (P=0.76 between the frequencies in untreated and treated eyes. Conclusion: Eyes of Japanese wet AMD patients had a higher abnormal FAF prevalence compared with control eyes. Among the three disease subtypes, abnormal patterns were least prevalent in PCV eyes. Keywords: age-related macular degeneration, fundus autofluorescence, polypoidal choroidal vasculopathy, retinal

  8. Eye movement monitoring of memory.

    Science.gov (United States)

    Ryan, Jennifer D; Riggs, Lily; McQuiggan, Douglas A; McQuiggan, Doug

    2010-08-15

    Explicit (often verbal) reports are typically used to investigate memory (e.g. "Tell me what you remember about the person you saw at the bank yesterday."), however such reports can often be unreliable or sensitive to response bias, and may be unobtainable in some participant populations. Furthermore, explicit reports only reveal when information has reached consciousness and cannot comment on when memories were accessed during processing, regardless of whether the information is subsequently accessed in a conscious manner. Eye movement monitoring (eye tracking) provides a tool by which memory can be probed without asking participants to comment on the contents of their memories, and access of such memories can be revealed on-line. Video-based eye trackers (either head-mounted or remote) use a system of cameras and infrared markers to examine the pupil and corneal reflection in each eye as the participant views a display monitor. For head-mounted eye trackers, infrared markers are also used to determine head position to allow for head movement and more precise localization of eye position. Here, we demonstrate the use of a head-mounted eye tracking system to investigate memory performance in neurologically-intact and neurologically-impaired adults. Eye movement monitoring procedures begin with the placement of the eye tracker on the participant, and setup of the head and eye cameras. Calibration and validation procedures are conducted to ensure accuracy of eye position recording. Real-time recordings of X,Y-coordinate positions on the display monitor are then converted and used to describe periods of time in which the eye is static (i.e. fixations) versus in motion (i.e., saccades). Fixations and saccades are time-locked with respect to the onset/offset of a visual display or another external event (e.g. button press). Experimental manipulations are constructed to examine how and when patterns of fixations and saccades are altered through different types of prior

  9. Dermal, Eye, and Oral Toxicological Evaluations.

    Science.gov (United States)

    1985-06-01

    produced no corneal opacity, iritis , hyperemia, chemosis, or discharge throughout the 72 hour observation period. This sample is non-irritating to...resolved in one eye by day 7 and in the other eye by day 14. Iritis was observed in all three eyes at 24 hours which resolved in one eye by 48 hours...other eye by day 7. Only one eye displayed iritis at 24 hours which resolved by the 72 hour observation period. Hyperemia, chemosis and discharge were

  10. Comparative diffusion tractography of corticostriatal motor pathways reveals differences between humans and macaques

    NARCIS (Netherlands)

    Neggers, S.F.W.; Zandbelt, B.B.; Schall, M.S.; Schall, J.D.

    2015-01-01

    The primate corticobasal ganglia circuits are understood to be segregated into parallel anatomically and functionally distinct loops. Anatomical and physiological studies in macaque monkeys are summarized as showing that an oculomotor loop begins with projections from the frontal eye fields (FEF) to

  11. EDITORIAL: The Eye and The Chip 2008 The Eye and The Chip 2008

    Science.gov (United States)

    Rizzo, Joseph F.; O'Malley, Edward R.; Hessburg, Philip C.

    2009-06-01

    Over the course of the past decade, The Eye and The Chip world congress on visual neuro-prosthetic devices has become a premier meeting for those who believe that 'artificial' vision will one day be used to improve the quality of life of visually impaired patients. Although substantial progress has been made, there are numerous unresolved issues, like the preferred methods for wireless communication, placement of devices, and materials and design among others. The Eye and The Chip meeting of 2008, held in Detroit on 12-14 June 2008, provided important new information about these and other important topics, and thus served to advance this field of scientific research. From a research seedling a decade ago to the crowd of superb presentations in Detroit last June, a very real sense of justifiable optimism has developed. The prospects of artificial vision are no longer remote. Many of the researchers expressed confidence that implantable devices will provide the hoped-for level of vision to justify their widespread use in the future. The often dramatic successes of cochlear implants continues to provide credence that artificial stimulation of nerve tissue is a plausible strategy to restore vision. The Eye and The Chip 2008 attracted researchers from four continents (North America, Europe, Asia and Australia). The meeting also benefited from the attendance and presentations by representatives of the FDA, who have been present for all The Eye and The Chip meetings. The 2008 meeting was also enhanced by the inclusion of a new and related scientific field that shares the goal of restoring vision to the blind—the field of molecular restoration of retinal function by insertion of channelrhodopsin. Just as the field of ophthalmology went from Ridley's primitive intraocular lens replacement to implants useful in virtually every cataract patient in one surgeon's clinical lifetime, the field of retinal prostheses seems to be following a very similar trajectory. Likewise, the

  12. The independence of eye movements in a stomatopod crustacean is task dependent.

    Science.gov (United States)

    Daly, Ilse M; How, Martin J; Partridge, Julian C; Roberts, Nicholas W

    2017-04-01

    Stomatopods have an extraordinary visual system, incorporating independent movement of their eyes in all three degrees of rotational freedom. In this work, we demonstrate that in the peacock mantis shrimp, Odontodactylus scyllarus, the level of ocular independence is task dependent. During gaze stabilization in the context of optokinesis, there is weak but significant correlation between the left and right eyes in the yaw degree of rotational freedom, but not in pitch and torsion. When one eye is completely occluded, the uncovered eye does not drive the covered eye during gaze stabilization. However, occluding one eye does significantly affect the uncovered eye, lowering its gaze stabilization performance. There is a lateral asymmetry, with the magnitude of the effect depending on the eye (left or right) combined with the direction of motion of the visual field. In contrast, during a startle saccade, the uncovered eye does drive a covered eye. Such disparate levels of independence between the two eyes suggest that responses to individual visual tasks are likely to follow different neural pathways. © 2017. Published by The Company of Biologists Ltd.

  13. Keeping our eyes on the eyes: the case of Arcimboldo.

    Science.gov (United States)

    Bubic, Andreja; Susac, Ana; Palmovic, Marijan

    2014-01-01

    While contemporaries often viewed his reversible composite heads as scherzi (jokes) and modem art connoisseurs as creative masterpieces, Giuseppe Arcimboldo's ingenious paintings served as inspiring stimuli for the present eye-tracking experiment. One group of participants viewed three chosen paintings in an upright, and another in an upside-down, orientation. We compared how participants viewed three selected areas of interest (AOIs) within the painting when these could, and could not, be identified as a face or distinct facial element (eyes and mouth). The obtained results indicate that the participants fixated the parts of the painting which represent faces more in the upright than in the inverted orientation. Furthermore, in the upright orientation the participants focused more on the upper AOls (eyes) than the lower AOIs (mouth). This was not the case for the inverted orientation of two paintings. In conclusion, the face inversion effect occurs even in this artistic context, and the gaze often goes where the eyes are.

  14. Wartime open globe eye injuries.

    Science.gov (United States)

    Plestina-Borjan, Ivna; Medvidovic-Grubisic, Maria; Zuljan, Igor; Lakos, Venera; Miljak, Snjezana; Markovic, Irena; Ivanisevic, Milan

    2010-03-01

    Open globe injuries are the most serious eye injuries in war as in peace time. The purpose of this study is to analyze wartime open globe eye injuries in 72 patients treated at the Department of Ophthalmology, Clinical Hospital of Split from July 1991 to April 1993, during the intensive war in Croatia and Bosnia and Herzegovina, and to evaluate crucial factors responsible for the functional success of the treatment. Wartime open globe eye injuries were retrospectively analyzed in 72 patients (80 eyes) hospitalized at Clinical Hospital of Split, Department of Ophthalmology, between July 1991 and April 1993. The causes and ways of wounding, localization of wounds and presence, nature and localization of the foreign body, as well as admission time, microsurgical management and other factors contributing to poor visual outcome were studied. Standard international classification of ocular traumas (the Birmingham Eye Trauma Terminology and the International Ocular Trauma Classification) was used for the classified and graded injuries. Open globe eye injuries amounted to 52.65% of all war injuries to the eyes. Bilateral injuries were found in eight patients (11.11%). The most frequent cause of the injures were fragments of explosive devices (more than two-thirds). Most of the patients were admitted to the hospital within 24 hours of the injury. Using current microsurgical techniques, the attempt was made to achieve not only anatomical but also functional recovery already in the primary treatment. In 30 eyes (37.50%) final visual acuity amounted to more than 0.1, and in 22 eyes (27.50%) it reached 0.5. There was a statistically significant correlation between admission within the first 12 hours and postoperative improved visual acuity (chi(2) = 4.53; p = 0.033). Statistically significantly better visual acuity was found in patients with lesions limited to the anterior segment of the eye. Primary enucleation or evisceration was performed only exceptionally: one enucleation

  15. The eyes of LITENING

    Science.gov (United States)

    Moser, Eric K.

    2016-05-01

    LITENING is an airborne system-of-systems providing long-range imaging, targeting, situational awareness, target tracking, weapon guidance, and damage assessment, incorporating a laser designator and laser range finders, as well as non-thermal and thermal imaging systems, with multi-sensor boresight. Robust operation is at a premium, and subsystems are partitioned to modular, swappable line-replaceable-units (LRUs) and shop-replaceable-units (SRUs). This presentation will explore design concepts for sensing, data storage, and presentation of imagery associated with the LITENING targeting pod. The "eyes" of LITENING are the electro-optic sensors. Since the initial LITENING II introduction to the US market in the late 90s, as the program has evolved and matured, a series of spiral functional improvements and sensor upgrades have been incorporated. These include laser-illuminated imaging, and more recently, color sensing. While aircraft displays are outside of the LITENING system, updates to the available viewing modules have also driven change, and resulted in increasingly effective ways of utilizing the targeting system. One of the latest LITENING spiral upgrades adds a new capability to display and capture visible-band color imagery, using new sensors. This is an augmentation to the system's existing capabilities, which operate over a growing set of visible and invisible colors, infrared bands, and laser line wavelengths. A COTS visible-band camera solution using a CMOS sensor has been adapted to meet the particular needs associated with the airborne targeting use case.

  16. Eyes of Things

    Directory of Open Access Journals (Sweden)

    Oscar Deniz

    2017-05-01

    Full Text Available Embedded systems control and monitor a great deal of our reality. While some “classic” features are intrinsically necessary, such as low power consumption, rugged operating ranges, fast response and low cost, these systems have evolved in the last few years to emphasize connectivity functions, thus contributing to the Internet of Things paradigm. A myriad of sensing/computing devices are being attached to everyday objects, each able to send and receive data and to act as a unique node in the Internet. Apart from the obvious necessity to process at least some data at the edge (to increase security and reduce power consumption and latency, a major breakthrough will arguably come when such devices are endowed with some level of autonomous “intelligence”. Intelligent computing aims to solve problems for which no efficient exact algorithm can exist or for which we cannot conceive an exact algorithm. Central to such intelligence is Computer Vision (CV, i.e., extracting meaning from images and video. While not everything needs CV, visual information is the richest source of information about the real world: people, places and things. The possibilities of embedded CV are endless if we consider new applications and technologies, such as deep learning, drones, home robotics, intelligent surveillance, intelligent toys, wearable cameras, etc. This paper describes the Eyes of Things (EoT platform, a versatile computer vision platform tackling those challenges and opportunities.

  17. Real Time Eye Template Detection and Tracking

    OpenAIRE

    2012-01-01

    There has been a growing interest in the field of facial expression recognition especially in the last two decades. An example of such a system is the improvement of driver carefulness and accident reduction. The driver’s face is tracked while he is driving and he is warned if there seems to be an alerting fact that can result in an accident such as sleepy eyes, or looking out of the road. Furthermore, with a facial feature tracker, it becomes possible to play a synthesized avatar so that it ...

  18. Eye Absence Does Not Regulate Planarian Stem Cells during Eye Regeneration.

    Science.gov (United States)

    LoCascio, Samuel A; Lapan, Sylvain W; Reddien, Peter W

    2017-02-27

    Dividing cells called neoblasts contain pluripotent stem cells and drive planarian flatworm regeneration from diverse injuries. A long-standing question is whether neoblasts directly sense and respond to the identity of missing tissues during regeneration. We used the eye to investigate this question. Surprisingly, eye removal was neither sufficient nor necessary for neoblasts to increase eye progenitor production. Neoblasts normally increase eye progenitor production following decapitation, facilitating regeneration. Eye removal alone, however, did not induce this response. Eye regeneration following eye-specific resection resulted from homeostatic rates of eye progenitor production and less cell death in the regenerating eye. Conversely, large head injuries that left eyes intact increased eye progenitor production. Large injuries also non-specifically increased progenitor production for multiple uninjured tissues. We propose a model for eye regeneration in which eye tissue production by planarian stem cells is not directly regulated by the absence of the eye itself. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. On subwavelength imaging with Maxwell's fish eye lens

    CERN Document Server

    Sun, Fei

    2010-01-01

    Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a subwavelength image of a sharp object may be achieved in some cases, however, its spot-size is larger than the spot size of the initial object field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a fish eye lens. Time-domain simulation is also given to verify our conclusion. Multi-point imaging for a single object point is also demonstrated.

  20. On subwavelength imaging of Maxwell's fish eye lens

    CERN Document Server

    Sun, Fei

    2010-01-01

    Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens, which has been claimed recently to be able to achieve perfect imaging. We show that such a Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in the Maxwell's fish eye. If only zero order mode is excited, a subwavelength image can be achieved, however, its spot-size is larger than the spot size of the source field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a modified fish eye bounded with perfectly electrical conductor (PEC). Explicit condition is given for achieving a subwavelength image. When this condition is not satisfied, a single line current source may give multiple image spots.

  1. Can Maxwell's fish eye lens really give perfect imaging?

    CERN Document Server

    Sun, Fei

    2010-01-01

    Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a good image of a sharp object may be achieved in some cases, however, its spot-size is larger than the spot size of the initial object field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a fish eye lens. Time-domain simulation is also given to verify our conclusion. Multi-point images for a single object point are also demonstrated.

  2. Eye Movements When Viewing Advertisements

    Directory of Open Access Journals (Sweden)

    Emily eHiggins

    2014-03-01

    Full Text Available In this selective review, we examine key findings on eye movements when viewing advertisements. We begin with a brief, general introduction to the properties and neural underpinnings of saccadic eye movements. Next, we provide an overview of eye movement behavior during reading, scene perception, and visual search, since each of these activities is, at various times, involved in viewing ads. We then review the literature on eye movements when viewing print ads and warning labels (of the kind that appear on alcohol and tobacco ads, before turning to a consideration of advertisements in dynamic media (television and the Internet. Finally, we propose topics and methodological approaches that may prove to be useful in future research.

  3. Juvenile eye growth, when completed?

    DEFF Research Database (Denmark)

    Fledelius, Hans C; Christensen, Anders S; Fledelius, Christian

    2014-01-01

    PURPOSE: To test Sorsby's classical statement of axial eye growth as completed at the age of 13 years, with a view also to differentiating between basic eye growth and juvenile elongation associated with eventual refractive change towards myopia. METHODS: (i) A total of 160 healthy eyes close...... was preferred for conventional ultrasound oculometry due to its extreme repeatability of measuring values, thus making it well fitted for evaluating very small differences. In particular, this had bearing for the decelerating end phase of growth in the longitudinal investigation. RESULTS: Sorby's statement...... about age 13 as general limit found support from the cross-sectional data, which suggested stable emmetropic eye size from about 11-12 years, with an average apparently outgrown male emmetropic value of 23.5 mm versus females' 22.9 mm. The longitudinal data, however, showed emmetropic growth also beyond...

  4. Eye movements when viewing advertisements

    Science.gov (United States)

    Higgins, Emily; Leinenger, Mallorie; Rayner, Keith

    2013-01-01

    In this selective review, we examine key findings on eye movements when viewing advertisements. We begin with a brief, general introduction to the properties and neural underpinnings of saccadic eye movements. Next, we provide an overview of eye movement behavior during reading, scene perception, and visual search, since each of these activities is, at various times, involved in viewing ads. We then review the literature on eye movements when viewing print ads and warning labels (of the kind that appear on alcohol and tobacco ads), before turning to a consideration of advertisements in dynamic media (television and the Internet). Finally, we propose topics and methodological approaches that may prove to be useful in future research. PMID:24672500

  5. Eyes on the Solar System

    Data.gov (United States)

    National Aeronautics and Space Administration — Eyes on the Solar System is a software package developed by NASA Jet Propulsion Laboratory and the California Institute of Technology using data provided by NASA's...

  6. Head and eye Echoencephalogram (image)

    Science.gov (United States)

    ... to test for abnormalities in the eye. The ultrasound helps evaluate the farthest part of the eyeball when there are cataracts. The test may help diagnose retinal detachment or other disorders and evaluate orbital lesions and intraocular lesions.

  7. Binocular eye tracking with the Tracking Scanning Laser Ophthalmoscope.

    Science.gov (United States)

    Stevenson, S B; Sheehy, C K; Roorda, A

    2016-01-01

    The development of high magnification retinal imaging has brought with it the ability to track eye motion with a precision of less than an arc minute. Previously these systems have provided only monocular records. Here we describe a modification to the Tracking Scanning Laser Ophthalmoscope (Sheehy et al., 2012) that splits the optical path in a way that slows the left and right retinas to be scanned almost simultaneously by a single system. A mirror placed at a retinal conjugate point redirects half of each horizontal scan line to the fellow eye. The collected video is a split image with left and right retinas appearing side by side in each frame. Analysis of the retinal motion in the recorded video provides an eye movement trace with very high temporal and spatial resolution. Results are presented from scans of subjects with normal ocular motility that fixated steadily on a green laser dot. The retinas were scanned at 4° eccentricity with a 2° square field. Eye position was extracted offline from recorded videos with an FFT based image analysis program written in Matlab. The noise level of the tracking was estimated to range from 0.25 to 0.5arcmin SD for three subjects. In the binocular recordings, the left eye/right eye difference was 1-2arcmin SD for vertical motion and 10-15arcmin SD for horizontal motion, in agreement with published values from other tracking techniques.

  8. A 1-year Study of Eye Trauma at Farabi Hospital

    Directory of Open Access Journals (Sweden)

    J. Faraji Oskooie

    1998-04-01

    Full Text Available The author conducted 1-year study investigating the causation and management of eye trauma at Farabi Eye' center. All patients sustaining eye injuries who were evaluated by ophthalmology service over one year interval were included."n. A formal questionnaire was completed with details of the injuiy being obtained. An ophthalmologic examination was performed on each patient, and examination findings and diagnostic tests obtained, diagnosis and treatment were recorded and analyzed."nNine hundreds and sixty-one injuries (65% occured in males and 503 (35% in females. The average age was 30 years. This study included 1464 eye injuries."nFour handreds and eighty-five (nearly 30% of patients were in pediatric age group. Seventy percent of all patients were admitted within 24 hours of their injury. Fourty percent of all injuries occurred in the street, 30% at home, 15% at the work place , the rest either in school or sport field."nAmong those older than 65 years of age, 70% of injuries were the result of fall. Seventy percent of all eye injuries were caused by blunt trauma. Diagnosis and management were recorded."nConclusions : Tehran and other metropolitans population is more likely to sustain eye trauma as the result of an assault and is less likely to be involved in a work- or sports-related one."nGiven poor compliance without patient management and follow-up, aggressive primary management may be indicated to optimize visual outcome

  9. A Note on Eye Movement

    CERN Document Server

    Bolina, O; Bolina, Oscar

    1998-01-01

    In a simplified fashion, the motion of the eyeball in its orbit consists of rotations around a fixed point. Therefore, this motion can be described in terms of the Euler's angles of rigid body dynamics. However, there is a physiological constraint in the motion of the eye which reduces to two its degrees of freedom. This paper reviews the basic features of the kinematics of the eye and the laws governing its motion.

  10. Talking with eye injury patients

    Directory of Open Access Journals (Sweden)

    Helen Roberts

    2016-01-01

    Full Text Available Patients with an eye injury are usually in pain and very frightened. They need a gentle, reassuring approach. Your first task is to assess the general state of your patient. If they are alert and orientated and their general health is good, you can continue to examine them in the eye department. If their immediate general health is at risk, you will have to address this first.

  11. Eye casualty services in London

    Science.gov (United States)

    Smith, H B; Daniel, C S; Verma, S

    2013-01-01

    The combined pressures of the European Working Time Directive, 4 h waiting time target, and growing rates of unplanned hospital attendances have forced a major consolidation of eye casualty departments across the country, with the remaining units seeing a rapid increase in demand. We examine the effect of these changes on the provision of emergency eye care in Central London, and see what wider lessons can be learned. We surveyed the managers responsible for each of London's 8 out-of-hours eye casualty services, analysed data on attendance numbers, and conducted detailed interviews with lead clinicians. At London's two largest units, Moorfields Eye Hospital and the Western Eye Hospital, annual attendance numbers have been rising at 7.9% per year (to 76 034 patients in 2010/11) and 9.6% per year (to 31 128 patients in 2010/11), respectively. Using Moorfields as a case study, we discuss methods to increase capacity and efficiency in response to this demand, and also examine some of the unintended consequences of service consolidation including patients travelling long distances to geographically inappropriate units, and confusion over responsibility for out-of-hours inpatient cover. We describe a novel ‘referral pathway' developed to minimise unnecessary travelling and delay for patients, and propose a forum for the strategic planning of London's eye casualty services in the future. PMID:23370420

  12. Arteriolar Diameters in Glaucomatous Eyes with Single-Hemifield Damage.

    Science.gov (United States)

    Russo, Andrea; Costagliola, Ciro; Rizzoni, Damiano; Ghilardi, Nausica; Turano, Raffaele; Semeraro, Francesco

    2016-05-01

    To examine the association between retinal arteriolar caliber and lumen, retinal sensitivity (RS), and retinal nerve fiber layer (RNFL) thickness in glaucomatous eyes with single-hemifield loss. We conducted a prospective, nonrandomized, case-control study of 20 eyes of 20 patients with glaucoma with visual field damage confined to a single hemifield. The control group was composed of 20 eyes of 20 normal subjects. For all the eyes, we performed optical coherence tomography to assess the RNFL and standard automated perimetry to evaluate RS. External and internal arteriolar diameters were assessed in vivo using scanning laser Doppler flowmetry. The RNFL was significantly thinner in glaucomatous eyes than in normal eyes (p < 0.001). In glaucomatous eyes, a positive correlation between sectorial RNFL thickness and the corresponding external and internal arteriolar diameters was found (r = 0.43, p = 0.05; r = 0.63, p = 0.003, respectively). The internal arteriolar diameter significantly correlated with RS in the corresponding abnormal hemifield (r = 0.44, p = 0.04). Compared with the normal hemifield, the internal arteriolar diameter, RNFL thickness, and RS were significantly reduced, whereas the external arteriolar diameter was unchanged in the abnormal hemifield. In glaucomatous eyes with single-hemifield damage, attenuation of retinal vessels was associated with a thinner RNFL and reduced RS. Moreover, a narrower lumen with increased wall-to-lumen ratio was found in the abnormal hemifield, supporting the hypothesis that vessel narrowing is likely secondary to a lower demand for blood flow in the glaucomatous areas of the retina.

  13. Eye Health in Sports and Recreation

    Science.gov (United States)

    ... Recreation Eye Injuries at Work Fireworks Eye Safety Sports Eye Injuries by the Numbers — Infographic Five Steps to Safer ... protection. High-Risk Sports For all age groups, sports-related eye injuries occur most frequently in baseball, basketball and racquet ...

  14. A New Method to Assess Eye Dominance

    Science.gov (United States)

    Valle-Inclan, Fernando; Blanco, Manuel J.; Soto, David; Leiros, Luz

    2008-01-01

    People usually show a stable preference for one of their eyes when monocular viewing is required ("sighting dominance") or under dichoptic stimulation conditions ("sensory eye-dominance"). Current procedures to assess this "eye dominance" are prone to error. Here we present a new method that provides a continuous measure of eye dominance and…

  15. Eye Movement Disorders in Dyslexia. Final Report.

    Science.gov (United States)

    Festinger, Leon; And Others

    Eye movements of 18 male and seven female dyslexic children and 10 normal children were evaluated to determine if eye movement disorders may be the cause of some of the symptoms associated with dyslexia. Data on eye movements were collected while Ss moved their eyes from one fixation point to another in a nonreading situation. Errors in vertical…

  16. Through Youthful Eyes.

    Science.gov (United States)

    UNESCO Courier, 1982

    1982-01-01

    This article presents findings from a questionnaire dealing with what young people think about the elderly and aging and how to bridge the generation gap. The role of the young in helping old people to become integrated in society is to encourage contacts in all fields. (UNESCO, Place de Fontenoy, 75700 Paris) (SSH)

  17. Improving College Students English Learning with Dr. Eye Android Mid

    Science.gov (United States)

    Yang, Ju Yin; Che, Pei-Chun

    2015-01-01

    This paper investigates college students' English language learning through use of Dr. Eye Android handheld mobile Internet device (MID). Compared to related studies, students' English learning using MIDs has not been evaluated and fully understood in the field of higher education. Quantitatively, the researchers used TOEIC pretest and posttest to…

  18. Calibration of an eye oximeter with a dynamic eye phantom

    Science.gov (United States)

    Nabili, A.; Bardakci, D.; Helling, K.; Matyas, C.; Muro, S.; Ramella-Roman, J. C.

    2008-02-01

    Measurements of oxygen saturation and flow in the retina can yield information about the eye health and the onset of eye pathologies such as Diabetic Retinopathy. Recently we have realized an instrument capable of measuring oxygenation in the retina using six different wavelengths and capable of measuring blood flow using speckle-based techniques. The calibration of such instrument is particularly difficult due to the layered structure of the eye and the lack of alternative measurement techniques. For this purpose we have realized an in vitro model of the human eye. The artificial eye is composed of four layers: the retina vessels, the choroids, the retinal pigmented epithelium (RPE), and the sclera. The retina vessels are modeled with 150 μm tube connected to a micro-pump delivering 34 μl/min. The micro-tube, the pump, and a blood reservoir were connected in a closed circulatory system; blood oxygenation in the vessel could be modified using an external oxygen reservoir. The optical properties of all other layers were mimicked using titanium dioxide as a scatterer and ink as an absorber. The absorption coefficient μa and the scattering coefficient µs of these layers were independently measured using an integrating sphere. Absorption and scattering coefficient of all layers were modified before experimental measurements and a Monte Carlo program was finally used to model the experimental results.

  19. Drugs affecting the eye.

    Science.gov (United States)

    Taylor, F

    1985-08-01

    This discussion reviews drugs that affect the eye, including antihyperglycemic agents; corticosteroids; antirheumatic drugs (quinolines, indomethacin, and allopurinol); psychiatric drugs (phenothiazine, thioridazine, and chlorpromazine); drugs used in cardiology (practolol, amiodarone, and digitalis gylcosides); drugs implicated in optic neuritis and atrophy, drugs with an anticholinergic action; oral contraceptives (OCs); and topical drugs and systemic effects. Refractive changes, either myopic or hypermetropic, can occur as a result of hyperglycemia, and variation in vision is sometimes a presenting symptom in diabetes mellitus. If it causes a change in the refraction, treatment of hyperglycemia almost always produces a temporary hypermetropia. A return to the original refractive state often takes weeks, sometimes months. There is some evidence that patients adequately treated with insulin improve more rapidly than those taking oral medication. Such patients always should be referred for opthalmological evaluation as other factors might be responsible, but it might not be possible to order the appropriate spectacle correction for some time. The most important ocular side effect of the systemic adiministration of corticosteroids is the formation of a posterior subcapsular cataract. Glaucoma also can result from corticosteroids, most often when they are applied topically. Corticosteroids have been implicated in the production of benign intracranial hypertension, which is paradoxical because they also are used in its treatment. The most important side effect of drugs such as chloroquine and hydroxychloroquine is an almost always irreversible maculopathy with resultant loss of central vision. Corneal and retinal changes similar to those caused by the quinolines have been reported with indomethacin, but there is some question about a cause and effect relationship. The National Registry of Drug Induced Ocular Side Effects in the US published 30 case histories of

  20. Improvement of Reading Speed and Eye Movements

    Directory of Open Access Journals (Sweden)

    Kenji Yokoi

    2011-05-01

    Full Text Available Although many studies have examined eye movements in reading, little is known which factors differentiate slow and fast readers. Recently, Rayner et al. (2010 reported that fast readers had a larger effective visual field than did slow readers by using the gaze-contingent window method. The fast readers they selected, however, may have acquired better attentional skills inherently or through long experience, and this visual superiority would improve reading performance. To clarify this issue, we investigated eye movements in reading while practicing speed reading. Participants (approx. 600 letters per minute in Japanese exercised speed reading programs for half an hour per day for about 30 days. Reading performance of Japanese editorial articles was recorded every five days of training by the gaze-contingent window method. Our results showed that the size of the effective visual field did not increase in the same manner as reading speed (up to 1000 lpm. Instead, we found that saccadic length became longer and less varied. Fixation duration and the number of regressions were also reduced. These findings suggest that efficiency of comprehension at a single gaze may be the important factor for reading speed.

  1. Trustworthy-Looking Face Meets Brown Eyes

    OpenAIRE

    Karel Kleisner; Lenka Priplatova; Peter Frost; Jaroslav Flegr

    2013-01-01

    We tested whether eye color influences perception of trustworthiness. Facial photographs of 40 female and 40 male students were rated for perceived trustworthiness. Eye color had a significant effect, the brown-eyed faces being perceived as more trustworthy than the blue-eyed ones. Geometric morphometrics, however, revealed significant correlations between eye color and face shape. Thus, face shape likewise had a significant effect on perceived trustworthiness but only for male faces, the eff...

  2. A method to reduce patient's eye lens dose in neuro-interventional radiology procedures

    Science.gov (United States)

    Safari, M. J.; Wong, J. H. D.; Kadir, K. A. A.; Sani, F. M.; Ng, K. H.

    2016-08-01

    Complex and prolonged neuro-interventional radiology procedures using the biplane angiography system increase the patient's risk of radiation-induced cataract. Physical collimation is the most effective way of reducing the radiation dose to the patient's eye lens, but in instances where collimation is not possible, an attenuator may be useful in protecting the eyes. In this study, an eye lens protector was designed and fabricated to reduce the radiation dose to the patients' eye lens during neuro-interventional procedures. The eye protector was characterised before being tested on its effectiveness in a simulated aneurysm procedure on an anthropomorphic phantom. Effects on the automatic dose rate control (ADRC) and image quality are also evaluated. The eye protector reduced the radiation dose by up to 62.1% at the eye lens. The eye protector is faintly visible in the fluoroscopy images and increased the tube current by a maximum of 3.7%. It is completely invisible in the acquisition mode and does not interfere with the clinical procedure. The eye protector placed within the radiation field of view was able to reduce the radiation dose to the eye lens by direct radiation beam of the lateral x-ray tube with minimal effect on the ADRC system.

  3. ASSOCIATION BETWEEN RETINAL HEMORRHAGIC PATTERNS AND PERFUSION STATUS IN EYES WITH ACUTE CENTRAL RETINAL VEIN OCCLUSION.

    Science.gov (United States)

    Muraoka, Yuki; Uji, Akihito; Tsujikawa, Akitaka; Murakami, Tomoaki; Ooto, Sotaro; Suzuma, Kiyoshi; Takahashi, Ayako; Iida, Yuto; Miwa, Yuko; Hata, Masayuki; Yoshimura, Nagahisa

    2017-03-01

    To evaluate peripheral retinal hemorrhagic patterns in eyes with acute central retinal vein occlusion, and to explore their clinical relevance in differentiating for the retinal perfusion status, through a prospective, and cross-sectional study. Fifty eyes with acute central retinal vein occlusion were included. Retinal hemorrhagic patterns at the equator and retinal perfusion status were evaluated by ultra-wide field fundus photography and fluorescein angiography. Retinal perfusion was categorized as nonischemic in 29 eyes, ischemic in 18 eyes, and undeterminable in 3 eyes. None of the examined eyes had flame-shaped retinal hemorrhages in the periphery. All hemorrhages were rounded-dot or blot and were variable in size. Particle analysis was performed to quantify hemorrhage size, and showed higher values in eyes having larger blot hemorrhages, and lower values in eyes having dot or smaller blot hemorrhages. Mean size of maximum peripheral dot or blot hemorrhage was larger in eyes classified as ischemic (10,763.0 ± 5,946.3 pixels) than as nonischemic (2,839.9 ± 1,153.6 pixels, P retinal perfusion status, which was 0.963 (P retinal hemorrhagic patterns at the equator in eyes with acute central retinal vein occlusion using particle analysis. The resulting hemorrhage size measurement was considered to be often useful in determining retinal perfusion status. Because they can be noninvasively evaluated with readily available equipment, peripheral hemorrhagic patterns might be good clinical markers of retinal perfusion.

  4. Ivermectin for onchocercal eye disease (river blindness)

    Science.gov (United States)

    Ejere, Henry OD; Schwartz, Ellen; Wormald, Richard; Evans, Jennifer R

    2015-01-01

    Background It is believed that ivermectin (a microfilaricide) could prevent blindness due to onchocerciasis. However, when given to everyone in communities where onchocerciasis is common, the effects of ivermectin on lesions affecting the eye are uncertain and data on whether the drug prevents visual loss are unclear. Objectives The aim of this review was to assess the effectiveness of ivermectin in preventing visual impairment and visual field loss in onchocercal eye disease. The secondary aim was to assess the effects of ivermectin on lesions affecting the eye in onchocerciasis. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 3), MEDLINE (January 1950 to April 2012), EMBASE (January 1980 to April 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 2 April 2012. Selection criteria We included randomised controlled trials with at least one year of follow-up comparing ivermectin with placebo or no treatment. Participants in the trials were people normally resident in endemic onchocercal communities with or without one or more characteristic signs of ocular onchocerciasis. Data collection and analysis Two review authors independently extracted data and assessed trial quality. We contacted study authors for additional information. As trials varied in design and setting, we were unable to perform a meta-analysis. Main results The review included four trials: two small studies (n = 398) in which people with onchocercal infection were given one dose of ivermectin or placebo and followed up for one year; and two larger community-based studies (n = 4941) whereby all individuals in

  5. Sexual Dimorphism in Eye Morphology in a Butterfly (Asterocampa leilia; Lepidoptera, Nymphalidae

    Directory of Open Access Journals (Sweden)

    Kristine S. Ziemba

    2000-01-01

    Full Text Available In the Empress Leilia butterfly, Asterocampa leilia, as in many insects, males have larger eyes than females. We explore the morphological causes and consequences of this dimorphism in eye size by comparing the corneal surface area, facet numbers, and patterns of variation in facet dimensions in males and females. We report that, with body size (measured by forewing length controlled, male eyes are consistently larger than female eyes, and that, although males and females do not differ significantly in the number of facets per eye, males have significantly larger facets. Also, males have disproportionately larger facets both frontally and dorsally. As a result of these sexual differences in eye structure, males are expected to have a larger and more acute visual field than females which could be advantageous in the context of this species' mate searching tactic.

  6. Inter-eye comparison of retinal oximetry and vessel caliber between eyes with asymmetrical glaucoma severity in different glaucoma subtypes

    Science.gov (United States)

    Cheng, Clarissa Shu Ming; Lee, Yi Fang; Ong, Charles; Yap, Zhu Li; Tsai, Andrew; Mohla, Aditi; Nongpiur, Monisha E; Aung, Tin; Perera, Shamira A

    2016-01-01

    Background To compare retinal vessel oxygenation and vessel caliber in primary angle-closure glaucoma (PACG), primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), and normal controls, as well as between eyes of asymmetrical glaucoma severity. Methods This was a prospective, cross-sectional study. The 159 subjects (PACG, n=39; POAG, n=41; NTG, n=41; normal controls, n=38) underwent retinal oxygen saturation measurements using the Oxymap T1 Retinal Oximeter, optical coherence tomography, and Humphrey visual field testing. Retinal oxygen saturation and vessel diameter were compared between the glaucoma groups and normal controls, as well as between eyes of asymmetrical glaucoma severity. Kruskal–Wallis test was performed for comparison among different subtypes of glaucoma. Wilcoxon signed-rank test was used to compare the inter-eye differences. Results Compared to normal controls, arteriolar oxygen saturation was increased in PACG eyes (P=0.048) but not in POAG or NTG eyes. There were no significant differences in oxygen saturation in venules or arteriovenous (AV) difference in all three glaucoma groups. Venular diameter was significantly reduced in all glaucoma groups compared to normal controls (P<0.001), but no such change was observed in arteriolar diameter (P=0.10). When comparing between eyes of asymmetrical glaucoma severity, arteriolar oxygen saturation (P=0.03) and AV difference (P=0.04) were significantly higher, while arteriolar diameter was significantly lower (P=0.001) in the worse eye in PACG group. There were no significant differences in oximetric parameters or vessel calibers between the worse and the better eyes in POAG and NTG groups. Conclusion Eyes with PACG showed increased arteriolar oxygen saturation and increased AV difference. This was not observed in POAG and NTG eyes. Arteriolar diameter in PACG and venular diameter in all three glaucoma groups were reduced. The difference observed in PACG eyes may be due to an increased

  7. Eye formation in rotating convection

    Science.gov (United States)

    Oruba, L.; Davidson, P. A.; Dormy, E.

    2017-02-01

    We consider rotating convection in a shallow, cylindrical domain. We examine the conditions under which the resulting vortex develops an eye at its core; that is, a region where the poloidal flow reverses and the angular momentum is low. For simplicity, we restrict ourselves to steady, axisymmetric flows in a Boussinesq fluid. Our numerical experiments show that, in such systems, an eye forms as a passive response to the development of a so-called eyewall, a conical annulus of intense, negative azimuthal vorticity that can form near the axis and separates the eye from the primary vortex. We also observe that the vorticity in the eyewall comes from the lower boundary layer, and relies on the fact the poloidal flow strips negative vorticity out of the boundary layer and carries it up into the fluid above as it turns upward near the axis. This process is effective only if the Reynolds number is sufficiently high for the advection of vorticity to dominate over diffusion. Finally we observe that, in the vicinity of the eye and the eyewall, the buoyancy and Coriolis forces are negligible, and so although these forces are crucial to driving and shaping the primary vortex, they play no direct role in eye formation in a Boussinesq fluid.

  8. Nutrients for the aging eye

    Directory of Open Access Journals (Sweden)

    Rasmussen HM

    2013-06-01

    Full Text Available Helen M Rasmussen,1 Elizabeth J Johnson2 1Educational Studies, Lesley University, Cambridge, MA, USA; 2Carotenoid and Health Laboratory, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA Abstract: The incidence of age-related eye diseases is expected to rise with the aging of the population. Oxidation and inflammation are implicated in the etiology of these diseases. There is evidence that dietary antioxidants and anti-inflammatories may provide benefit in decreasing the risk of age-related eye disease. Nutrients of interest are vitamins C and E, β-carotene, zinc, lutein, zeaxanthin, and the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid. While a recent survey finds that among the baby boomers (45–65 years old, vision is the most important of the five senses, well over half of those surveyed were not aware of the important nutrients that play a key role in eye health. This is evident from a national survey that finds that intake of these key nutrients from dietary sources is below the recommendations or guidelines. Therefore, it is important to educate this population and to create an awareness of the nutrients and foods of particular interest in the prevention of age-related eye disease. Keywords: nutrition, aging, eye health

  9. Best practice eye care models

    Science.gov (United States)

    Qureshi, Babar M; Mansur, Rabiu; Al-Rajhi, Abdulaziz; Lansingh, Van; Eckert, Kristen; Hassan, Kunle; Ravilla, Thulasiraj; Muhit, Mohammad; Khanna, Rohit C; Ismat, Chaudhry

    2012-01-01

    Since the launching of Global Initiative, VISION 2020 “the Right to Sight” many innovative, practical and unique comprehensive eye care services provision models have evolved targeting the underserved populations in different parts of the World. At places the rapid assessment of the burden of eye diseases in confined areas or utilizing the key informants for identification of eye diseases in the communities are promoted for better planning and evidence based advocacy for getting / allocation of resources for eye care. Similarly for detection and management of diabetes related blindness, retinopathy of prematurity and avoidable blindness at primary level, the major obstacles are confronted in reaching to them in a cost effective manner and then management of the identified patients accordingly. In this regard, the concept of tele-ophthalmology model sounds to be the best solution. Whereas other models on comprehensive eye care services provision have been emphasizing on surgical output through innovative scales of economy that generate income for the program and ensure its sustainability, while guaranteeing treatment of the poorest of the poor. PMID:22944741

  10. Secrets in the eyes of Black Oystercatchers: A new sexing technique

    Science.gov (United States)

    Guzzetti, B.M.; Talbot, S.L.; Tessler, D.F.; Gill, V.A.; Murphy, E.C.

    2008-01-01

    Sexing oystercatchers in the field is difficult because males and females have identical plumage and are similar in size. Although Black Oystercatchers (Haematopus bachmani) are sexually dimorphic, using morphology to determine sex requires either capturing both pair members for comparison or using discriminant analyses to assign sex probabilistically based on morphometric traits. All adult Black Oystercatchers have bright yellow eyes, but some of them have dark specks, or eye flecks, in their irides. We hypothesized that this easily observable trait was sex-linked and could be used as a novel diagnostic tool for identifying sex. To test this, we compared data for oystercatchers from genetic molecular markers (CHD-W/CHD-Z and HINT-W/HINT-Z), morphometric analyses, and eye-fleck category (full eye flecks, slight eye flecks, and no eye flecks). Compared to molecular markers, we found that discriminant analyses based on morphological characteristics yielded variable results that were confounded by geographical differences in morphology. However, we found that eye flecks were sex-linked. Using an eye-fleck model where all females have full eye flecks and males have either slight eye flecks or no eye flecks, we correctly assigned the sex of 117 of 125 (94%) oystercatchers. Using discriminant analysis based on morphological characteristics, we correctly assigned the sex of 105 of 119 (88%) birds. Using the eye-fleck technique for sexing Black Oystercatchers may be preferable for some investigators because it is as accurate as discriminant analysis based on morphology and does not require capturing the birds. ??2008 Association of Field Ornithologists.

  11. Microcystic Inner Nuclear Layer Changes and Retinal Nerve Fiber Layer Defects in Eyes with Glaucoma.

    Directory of Open Access Journals (Sweden)

    Tomoko Hasegawa

    Full Text Available To examine microcystic inner nuclear layer (INL changes in glaucomatous eyes and to determine associated factors.Retrospective, cross-sectional, observational study.Two hundred seventeen eyes of 133 patients with primary open angle glaucoma (POAG, 41 eyes of 32 patients with preperimetric glaucoma and 181 normal eyes of 117 subjects were ultimately included. Microcystic INL lesions were examined with infrared fundus images and with 19 vertical spectral domain optical coherence tomography (SD-OCT images in the macular area.Microcystic INL changes were observed in 6.0% of eyes with POAG, but none of the normal eyes or eyes with preperimetric glaucoma showed microcystic INL changes. The proportion of eyes with advanced glaucoma was significantly larger (P = 0.013 in eyes with microcystic lesions than without. The visual field mean deviation (MD slope was also significantly worse (P = 0.027 in eyes with microcystic lesions. No significant differences were observed in age, sex, refraction, axial length, intraocular pressure, or MD value between eyes with and without microcystic INL lesions. In several cases, microcystic INL lesions occurred along with glaucomatous visual field progression. The retinal nerve fiber layer (RNFL thickness (P = 0.013 and ganglion cell layer (GCL + inner plexiform layer thickness (P = 0.023 were significantly lower in areas with microcystic lesions than without. The INL was also significantly thicker (P = 0.002 in areas with microcystic lesions.Microcystic INL lesions in glaucomatous eyes are closely associated with RNFL and GCL thinning and correlated with worse MD slope. These INL lesions may indicate focal and progressive damage in glaucoma.

  12. Advances in Gene Therapy for Diseases of the Eye.

    Science.gov (United States)

    Petit, Lolita; Khanna, Hemant; Punzo, Claudio

    2016-08-01

    Over the last few years, huge progress has been made with regard to the understanding of molecular mechanisms underlying the pathogenesis of neurodegenerative diseases of the eye. Such knowledge has led to the development of gene therapy approaches to treat these devastating disorders. Challenges regarding the efficacy and efficiency of therapeutic gene delivery have driven the development of novel therapeutic approaches, which continue to evolve the field of ocular gene therapy. In this review article, we will discuss the evolution of preclinical and clinical strategies that have improved gene therapy in the eye, showing that treatment of vision loss has a bright future.

  13. Advances in Gene Therapy for Diseases of the Eye

    Science.gov (United States)

    Petit, Lolita; Khanna, Hemant; Punzo, Claudio

    2016-01-01

    Over the last few years, huge progress has been made with regard to the understanding of molecular mechanisms underlying the pathogenesis of neurodegenerative diseases of the eye. Such knowledge has led to the development of gene therapy approaches to treat these devastating disorders. Challenges regarding the efficacy and efficiency of therapeutic gene delivery have driven the development of novel therapeutic approaches, which continue to evolve the field of ocular gene therapy. In this review article, we will discuss the evolution of preclinical and clinical strategies that have improved gene therapy in the eye, showing that treatment of vision loss has a bright future. PMID:27178388

  14. Yarbus, Eye Movements, and Vision

    Directory of Open Access Journals (Sweden)

    Benjamin W Tatler

    2010-04-01

    Full Text Available The impact of Yarbus's research on eye movements was enormous following the translation of his book Eye Movements and Vision into English in 1967. In stark contrast, the published material in English concerning his life is scant. We provide a brief biography of Yarbus and assess his impact on contemporary approaches to research on eye movements. While early interest in his work focused on his study of stabilised retinal images, more recently this has been replaced with interest in his work on the cognitive influences on scanning patterns. We extended his experiment on the effect of instructions on viewing a picture using a portrait of Yarbus rather than a painting. The results obtained broadly supported those found by Yarbus.

  15. Phantom pain after eye amputation

    DEFF Research Database (Denmark)

    Rasmussen, Marie L R; Prause, Jan U; Toft, Peter B

    2011-01-01

    Purpose: To characterize the quality of phantom pain, its intensity and frequency following eye amputation. Possible triggers and relievers of phantom pain are investigated. Methods: The hospital database was searched using surgery codes for patients who received ocular evisceration, enucleation,...... appears to be similar to the phantom pain suffered by limb amputees. Patients should be informed about this potential complication before surgery.......Purpose: To characterize the quality of phantom pain, its intensity and frequency following eye amputation. Possible triggers and relievers of phantom pain are investigated. Methods: The hospital database was searched using surgery codes for patients who received ocular evisceration, enucleation...... was conducted by a trained interviewer. Results: Of the 173 patients in the study, 39 experienced phantom pain. The median age of patients who had experienced phantom pain was 45 years (range: 19–88). Follow-up time from eye amputation to participation in the investigation was 4 years (range: 2–46). Phantom...

  16. Estimation of eye absorbed doses in head & neck radiotherapy practices using thermoluminescent detectors

    Directory of Open Access Journals (Sweden)

    Gh Bagheri

    2011-09-01

    Full Text Available  Determination of eye absorbed dose during head & neck radiotherapy is essential to estimate the risk of cataract. Dose measurements were made in 20 head & neck cancer patients undergoing 60Co radiotherapy using LiF(MCP thermoluminescent dosimeters. Head & neck cancer radiotherapy was delivered by fields using SAD & SSD techniques. For each patient, 3 TLD chips were placed on each eye. Head & neck dose was about 700-6000 cGy in 8-28 equal fractions. The range of eye dose is estimated to be (3.49-639.1 mGy with a mean of maximum dose (98.114 mGy, which is about 3 % of head & neck dose. Maximum eye dose was observed for distsnces of about 3 cm from edge of the field to eye.

  17. Layer-specific refinement of visual cortex function after eye opening in the awake mouse

    National Research Council Canada - National Science Library

    Hoy, Jennifer L; Niell, Cristopher M

    2015-01-01

    .... Here, we use multisite electrophysiological recording in the awake mouse across an extended period of development, starting at eye opening, to measure receptive field properties and behavioral-state...

  18. The sightless eyes of reason

    DEFF Research Database (Denmark)

    Andrade-Molina, Melissa; Valero, Paola

    2015-01-01

    There is a gap between the aims of school geometry in terms of the teaching of spatial abilities to young children, and the dominance of a school geometry rooted in Euclid’s axioms and abstractions. Such gap is not to be explained in terms of a “misimplementation” of the curricular intentions. Ra...... geometry curriculum. We argue that school geometry fabricates the scientific minds of the future by training students to see not with the eyes of their bodies, but with the eyes of reason and logic...

  19. Eye Redness Image Processing Techniques

    Science.gov (United States)

    Adnan, M. R. H. Mohd; Zain, Azlan Mohd; Haron, Habibollah; Alwee, Razana; Zulfaezal Che Azemin, Mohd; Osman Ibrahim, Ashraf

    2017-09-01

    The use of photographs for the assessment of ocular conditions has been suggested to further standardize clinical procedures. The selection of the photographs to be used as scale reference images was subjective. Numerous methods have been proposed to assign eye redness scores by computational methods. Image analysis techniques have been investigated over the last 20 years in an attempt to forgo subjective grading scales. Image segmentation is one of the most important and challenging problems in image processing. This paper briefly outlines the comprehensive of image processing and the implementation of image segmentation in eye redness.

  20. Eye mechanics and their implications for eye movement control

    NARCIS (Netherlands)

    Koene, Ansgar Roald

    2002-01-01

    The topic of this thesis is the investigation of the mechanical properties of the oculomotor system and the implications of these properties for eye movement control. The investigation was conducted by means of computer models and simulations. This allowed us to combine data from anatomy, physiology

  1. Measurement of eye lens dose for Varian On-Board Imaging with different cone-beam computed tomography acquisition techniques.

    Science.gov (United States)

    Deshpande, Sudesh; Dhote, Deepak; Thakur, Kalpna; Pawar, Amol; Kumar, Rajesh; Kumar, Munish; Kulkarni, M S; Sharma, S D; Kannan, V

    2016-01-01

    The objective of this work was to measure patient eye lens dose for different cone-beam computed tomography (CBCT) acquisition protocols of Varian's On-Board Imaging (OBI) system using optically stimulated luminescence dosimeter (OSLD) and to study the variation in eye lens dose with patient geometry and distance of isocenter to the eye lens. During the experimental measurements, OSLD was placed on the patient between the eyebrows of both eyes in line of nose during CBCT image acquisition to measure eye lens doses. The eye lens dose measurements were carried out for three different cone-beam acquisition protocols (standard dose head, low-dose head [LDH], and high-quality head [HQH]) of Varian OBI. Measured doses were correlated with patient geometry and distance between isocenter and eye lens. Measured eye lens doses for standard head and HQH protocols were in the range of 1.8-3.2 mGy and 4.5-9.9 mGy, respectively. However, the measured eye lens dose for the LDH protocol was in the range of 0.3-0.7 mGy. The measured data indicate that eye lens dose to patient depends on the selected imaging protocol. It was also observed that eye lens dose does not depend on patient geometry but strongly depends on distance between eye lens and treatment field isocenter. However, undoubted advantages of imaging system should not be counterbalanced by inappropriate selection of imaging protocol, especially for very intense imaging protocol.

  2. Reading beyond the glance: eye tracking in neurosciences.

    Science.gov (United States)

    Popa, Livia; Selejan, Ovidiu; Scott, Allan; Mureşanu, Dafin F; Balea, Maria; Rafila, Alexandru

    2015-05-01

    From an interdisciplinary approach, the neurosciences (NSs) represent the junction of many fields (biology, chemistry, medicine, computer science, and psychology) and aim to explore the structural and functional aspects of the nervous system. Among modern neurophysiological methods that "measure" different processes of the human brain to salience stimuli, a special place belongs to eye tracking (ET). By detecting eye position, gaze direction, sequence of eye movement and visual adaptation during cognitive activities, ET is an effective tool for experimental psychology and neurological research. It provides a quantitative and qualitative analysis of the gaze, which is very useful in understanding choice behavior and perceptual decision making. In the high tech era, ET has several applications related to the interaction between humans and computers. Herein, ET is used to evaluate the spatial orienting of attention, the performance in visual tasks, the reactions to information on websites, the customer response to advertising, and the emotional and cognitive impact of various spurs to the brain.

  3. Development of the compound eyes of dragonflies (Odonata). II. Development of the larval compound eyes.

    Science.gov (United States)

    Sherk, T E

    1978-01-01

    The development of the compound eye was analyzed by marking individual ommatidia and by studying naturally occurring pigment band patterns. New ommatidia are added to the eye along its anterior margin. This changes the directions of view of the older ommatidia with the greatest change occurring in the fovea. New ommatidia are added to the fovea medially, and old ones are removed laterally as their interommatidial angles and directions of view in the visual field change. Over one-third of the aeshnid ommatidia are foveal during at least one of the early larval instars, and are then used for peripheral vision later in development. The design of each ommatidium is a compromise so that it is adapted for all stages of development, but sometimes better adapted for one instar than for others. Factors which are balanced for best vision are lens diameter, facet admission function, interommatidial angle, and inclination of the optic axis to the eye surface. Ommatidia are described in terms of these factors throughout their life history, from initial differentiation anteriorly, through passage through the fovea, to their final relatively posterior location.

  4. Pregnancy and Eye

    Directory of Open Access Journals (Sweden)

    Anubhav Chauhan

    2016-03-01

    Full Text Available Visual obscurations are common during pregnancy. The ocular effects of pregnancy may be physiological,pathological or may be modifications of pre-existing conditions. While most of the described changes are transient in nature, others extend beyond delivery and may lead to permanent visual impairment. Also, pregnancy can affect vision through systemic disease that are either specific to the pregnancy itself or systemic diseases that occur more frequently in relation to pregnancy. Neuro-ophthalmological disorders should be kept in mind in pregnant women presenting with visual acuity or field loss. Therefore, it is important to be aware of the ocular changes in pregnancy in order to counsel and advice women who currently are, or are planning to become pregnant. [Archives Medical Review Journal 2016; 25(1.000: 1-13

  5. Dengue eye disease.

    Science.gov (United States)

    Ng, Aaron W; Teoh, Stephen C

    2015-01-01

    Dengue fever, a viral disease epidemic in some parts of the world, is of considerable international concern, with a growing incidence owing to developing urbanization, tourism, and trade. Ocular manifestations of dengue fever are uncommon, but of great significance. Proposed mechanisms include direct viral infection as well as immunologic phenomena. Common manifestations include subconjunctival, vitreous, and retinal hemorrhages; posterior uveitis; optic neuritis; and maculopathies such as foveolitis, hemorrhage, and edema. Main symptoms include blurring of vision, scotomata, metamorphopsia, and floaters. Diagnostic and monitoring investigations described included optical coherence tomography, fundus fluorescein and indocyanine green angiography, visual field analysis, and electrophysiologic tests. Management is based on clinical presentation and includes active surveillance as well as various anti-inflammatory and immunosuppressive therapies. There have been no prospective, randomized therapeutic trials, and it is unclear if the disease is self-limiting or if treatment is actually beneficial. Prognosis varies, ranging from full resolution to permanent vision loss despite intervention.

  6. Stars in his eyes

    CERN Multimedia

    2007-01-01

    The Swedish astronaut Christer Fuglesang, a former CERN physicist now working for ESA, made his debut space flight last December. On 14 June he returned to CERN to talk about the experience. Christer Fuglesang during one of his spacewalks last December to upgrade the building of the International Space Station (ISS). Image Credit: NASA Christer Fuglesang (left) and his family visit the ATLAS experiment guided by Peter Jenni, the experiment’s spokesperson (right).Does an astronaut make a good cosmic ray detector? A particle physicist is undoubtedly very well placed to answer this kind of question. And as a former CERN physicist and now an astronaut with the European Space Agency (ESA), where he has worked since 1992, Christer Fuglesang has experience of both fields. Last December witnessed his first space journey, a 12-day mission on board the ISS International Space Station (see Bulletin No. ...

  7. Into the Eye

    Science.gov (United States)

    Ewers, Richard G.

    2011-01-01

    NASA's aeronautical research not only encompasses advancing aircraft technology and aviation safety for today and the future, but it also has a branch that deals with Airborne Science. This Airborne Science branch possesses unique airborne flight vehicles (manned and unmanned) whose sole purpose is to take scientists and their experiments anywhere in the world, into nearly any climatic condition, to gather the data they need for their research. This research spans such fields as; global warming, weather analysis, air and water pollution, mineral and archaeology search, earthquake damage and prediction, and yes, hurricanes. The data we obtain will hopefully, one day, allow us to better understand our planet, its natural forces and man's interaction with them.

  8. Eye-movements and ongoing task processing.

    Science.gov (United States)

    Burke, David T; Meleger, Alec; Schneider, Jeffrey C; Snyder, Jim; Dorvlo, Atsu S S; Al-Adawi, Samir

    2003-06-01

    This study tests the relation between eye-movements and thought processing. Subjects were given specific modality tasks (visual, gustatory, kinesthetic) and assessed on whether they responded with distinct eye-movements. Some subjects' eye-movements reflected ongoing thought processing. Instead of a universal pattern, as suggested by the neurolinguistic programming hypothesis, this study yielded subject-specific idiosyncratic eye-movements across all modalities. Included is a discussion of the neurolinguistic programming hypothesis regarding eye-movements and its implications for the eye-movement desensitization and reprocessing theory.

  9. The Effect of Cataract on Eye Movement Perimetry

    Directory of Open Access Journals (Sweden)

    G. Thepass

    2015-01-01

    Full Text Available Purpose. To determine how different grades of cataract affect sensitivity threshold and saccadic reaction time (SRT in eye movement perimetry (EMP. Methods. In EMP, the visual field is tested by assessing the saccades that a subject makes towards peripheral stimuli using an eye tracker. Forty-eight cataract patients underwent pre- and postoperative EMP examination in both eyes. The subjects had to fix a central stimulus presented on the eye tracker monitor and to look at any detected peripheral stimulus upon its appearance. A multilevel mixed model was used to determine the factors that affected the sensitivity threshold and the SRT as a function of cataract grade. Results. We found no effect of cataract severity (LOCS III grades I through IV on SRT and the sensitivity thresholds. In cataract of LOCS III grade V, however, we found an increase by 27% and 21% (p<0.001, respectively, compared to the SRT and the sensitivity threshold in LOCS III grade I. Eyes that underwent cataract surgery showed no change in mean SRTs and sensitivity thresholds after surgery in LOCS III grade IV and lower. Conclusion. The present study shows that EMP can be readily used in patients with cataract with LOCS III grade IV and below.

  10. USING EYE TRACKING TO MEASURE ONLINE INTERACTIVITY: A THEORETICAL FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Adriana-Emilia ROBU

    2013-06-01

    Full Text Available Notwithstanding that each and every company, even the sweetshop around the corner has found its way to the Internet, some customers still hesitate to shop online or to shop from one site and ignore the other. In order to build an online effective communication between the participants, one of the most important factors is interactivity. In the last decade it received extensive attention in the marketing literature, but few are the studies which have seen new methods to measure it. Eye tracking technology has been broadly used in the cognitive sciences. The purpose of this study is to investigate the existing literature in order to give insights into the eye tracking methodology when measuring the online interactivity. It also describes the eye tracking technology in general, extracts various examples from the eye tracking research field, with different applications, highlights its importance when analyzing the online consumer behavior, giving examples from various studies and finds the key points of the methodological difficulties. Finally, this work has an important merit for the future studies when taking into consideration the eye tracking technology in the online interactivity research and further, it is relevant for marketers, regarding the enhancement of online interactive interfaces and web or mobile applications.

  11. Peripheral Refraction, Peripheral Eye Length, and Retinal Shape in Myopia.

    Science.gov (United States)

    Verkicharla, Pavan K; Suheimat, Marwan; Schmid, Katrina L; Atchison, David A

    2016-09-01

    To investigate how peripheral refraction and peripheral eye length are related to retinal shape. Relative peripheral refraction (RPR) and relative peripheral eye length (RPEL) were determined in 36 young adults (M +0.75D to -5.25D) along horizontal and vertical visual field meridians out to ±35° and ±30°, respectively. Retinal shape was determined in terms of vertex radius of curvature Rv, asphericity Q, and equivalent radius of curvature REq using a partial coherence interferometry method involving peripheral eye lengths and model eye raytracing. Second-order polynomial fits were applied to RPR and RPEL as functions of visual field position. Linear regressions were determined for the fits' second order coefficients and for retinal shape estimates as functions of central spherical refraction. Linear regressions investigated relationships of RPR and RPEL with retinal shape estimates. Peripheral refraction, peripheral eye lengths, and retinal shapes were significantly affected by meridian and refraction. More positive (hyperopic) relative peripheral refraction, more negative RPELs, and steeper retinas were found along the horizontal than along the vertical meridian and in myopes than in emmetropes. RPR and RPEL, as represented by their second-order fit coefficients, correlated significantly with retinal shape represented by REq. Effects of meridian and refraction on RPR and RPEL patterns are consistent with effects on retinal shape. Patterns derived from one of these predict the others: more positive (hyperopic) RPR predicts more negative RPEL and steeper retinas, more negative RPEL predicts more positive relative peripheral refraction and steeper retinas, and steeper retinas derived from peripheral eye lengths predict more positive RPR.

  12. NotifEye

    DEFF Research Database (Denmark)

    Lucero, Andrés; Vetek, Akos

    2014-01-01

    In this paper we explore the use of interactive eyewear in public. We introduce NotifEye, an application that allows a person to receive social network notifications on interactive glasses while walking on a busy street. The prototype uses a minimalistic user interface (UI) for interactive glasses...

  13. Deformable Models for Eye Tracking

    DEFF Research Database (Denmark)

    Vester-Christensen, Martin; Leimberg, Denis; Ersbøll, Bjarne Kjær;

    2005-01-01

    A deformable template method for eye tracking on full face images is presented. The strengths of the method are that it is fast and retains accuracy independently of the resolution. We compare the me\\$\\backslash\\$-thod with a state of the art active contour approach, showing that the heuristic...

  14. Preventing eye injuries in quarries

    Directory of Open Access Journals (Sweden)

    Richard Wormald

    2016-01-01

    Full Text Available Eye injuries often occur in the workplace in low and middle-income countries, particularly in the construction, agricultural, mining, and manufacturing industries. Even if there are safety regulations in these industries, their enforcement is often unsatisfactory, and owners are not required to provide safety equipment.

  15. Silence, an Eye of Knowledge

    Directory of Open Access Journals (Sweden)

    Mehdi Aghamohammadi

    2017-04-01

    Full Text Available One of the conspicuous features of the twentieth-century West was silence. This idea could be supported by examining reflections of Ludwig Wittgenstein, Fritz Mauthner, John Cage, Samuel Beckett, Ihab Hassan, Franz Kafka, Wassily Kandinsky, Jean-Paul Sartre, Virginia Woolf, Wolfgang Iser, Jacques Derrida, and Pierre Macherey. To me, silence is not a mere theory, but rather a phenomenon from which we can get practical benefits. I believe silence is an eye, eye of knowledge. We can broaden our knowledge of the world through silence. To convey the idea that silence is an eye, I have concocted the word slence, where  has replaced the letter i and stands for the eye. This means knowledge can enable us to see, thereby acquiring knowledge of, what used to be invisible, and accordingly unknowable. In other words, through silence, we can achieve a certain type of literacy. I substantiate this claim by exploring the Horus myth, Ojo de Dios, John Cage’s 4' 33", the nature of Expressionist paintings, Hinduism, thoughts of Hermes Trismegistus and Ibn al-Arabi, and practices of Mohammad, the prophet of Islam.

  16. Autostereoscopic display with eye tracking

    Science.gov (United States)

    Tomono, Takao; Hoon, Kyung; Ha, Yong Soo; Kim, Sung-Sik; Son, Jung-Young

    2002-05-01

    Auto-stereoscopic 21-inch display with eye tracking having wide viewing zone and bright image was fabricated. The image of display is projected to retinal through several optical components. We calculated optical system for wider viewing zone by using Inverse-Ray Trace Method. The viewing zone of first model is 155mm (theoretical value: 161mm). We could widen viewing zone by controlling paraxial radius of curvature of spherical mirror, the distance between lenses and so on. The viewing zone of second model is 208mm. We used two spherical mirrors to obtain twice brightness. We applied eye-tracking system to the display system. Eye recognition is based on neural network card based on ZICS technology. We fabricated Auto-stereoscopic 21-inch display with eye tracking. We measured viewing zone based on illumination area. The viewing zone was 206mm, which was close to theoretical value. We could get twice brightness also. We could see 3D image according to position without headgear.

  17. Improving eye care in Rwanda.

    Science.gov (United States)

    Binagwaho, Agnes; Scott, Kirstin; Rosewall, Thomas; Mackenzie, Graeme; Rehnborg, Gweneth; Hannema, Sjoerd; Presente, Max; Noe, Piet; Mathenge, Wanjiku; Nkurikiye, John; Habiyaremye, Francois; Dushime, Theophile

    2015-06-01

    Visual impairment affects nearly 285 million people worldwide. Although there has been much progress in combating the burden of visual impairment through initiatives such as VISION 2020, barriers to progress, especially in African countries, remain high. The Rwandan Ministry of Health has formed partnerships with several nongovernmental organizations and has worked to integrate their efforts to prevent and treat visual impairment, including presbyopia. Rwanda, an eastern African country of approximately 11 million people. The Rwandan Ministry of Health developed a single national plan that allows key partners in vision care to coordinate more effectively in measuring eye disease, developing eye care infrastructure, building capacity, controlling disease, and delivering and evaluating services. Collaboration between stakeholders under a single national plan has ensured that resources and efforts are complementary, optimizing the ability to provide eye care. Improved access to primary eye care and insurance coverage has increased demand for services at secondary and tertiary levels. A comprehensive strategy that includes prevention as well as a supply chain for glasses and lenses is needed.

  18. Eye surgery in the elderly

    Directory of Open Access Journals (Sweden)

    Raczyńska D

    2016-04-01

    Full Text Available Dorota Raczyńska, Leopold Glasner, Ewelina Serkies-Minuth, Magdalena A Wujtewicz, Kamila Mitrosz Department of Ophthalmology, Medical University of Gdansk, Gdansk, Poland Abstract: Extending life expectancy is a human achievement. It does however entail problems. Ophthalmic treatments are widely recognized as having a low risk of general complications. A classic example is cataract surgery, considered to be one of the safest and most frequently performed surgical procedures in the world. However, advanced age brings with it risks that should be considered before surgery. Eye operations, as with procedures on other organs, are largely dependent on the quality of surgical tissues. Therefore, the elderly are at increased risk of complications. Improved general health and postoperative follow-up with the use of noninvasive technologies such as optical coherence tomography translate into lower intraoperative risk and better postoperative prognosis. In this review, we discuss the impact of general health on operational prognosis, therapeutic problems, and technical difficulties which a surgeon and anesthesiologist may encounter in the process. We also consider new technology and strategies specifically aimed at treating eye conditions in the elderly. Keywords: eye surgery, eye aging, anesthesiology in ophthalmology, cataract, glaucoma, vitrectomy, age-related macular degeneration

  19. Building the eye care team

    Directory of Open Access Journals (Sweden)

    Thulasiraj Ravilla

    2014-07-01

    Full Text Available Eye care services are people intensive. They require the right people (competence, in the right numbers (capacity, in the right mix (team with the right resources and processes (enabling conditions to ensure effective and sustainable delivery of patient care.

  20. Anticipatory Eye Movements in Congkak

    Directory of Open Access Journals (Sweden)

    Sheryl Chong

    2011-05-01

    Full Text Available Congkak is a traditional Malaysian board game involving two players taking turns to pick up marbles from a series of holes on the board. We used this game as a model to explore the role of anticipatory eye movements during natural actions (in this case serially picking up/putting marbles as novices learnt the game. Prior work on eye and hand movements in natural behaviour shows that much of the demand on the visual system is computed at the moment it is needed and doesn't depend on information acquired from previous fixations. Vision is driven by the task demands. However, anticipatory fixations to upcoming targets of manipulation have recently been shown to confer spatial accuracy and influence the eye-hand latency. We find that experience with the game also influences the deployment of these anticipatory “look-ahead” fixations, and that their influence on eye-hand latency varies with experience. Results suggest that as our experience in Congkak grows, so does our knowledge of the space relationships necessary for task success.

  1. 'An eye, for eyes - mission' - From dream to reality

    Directory of Open Access Journals (Sweden)

    Parikumar P

    2013-10-01

    Full Text Available Corneal transplantation has been in routine practice to treat corneal endothelial diseases like Bullous Keratopathy, in which either the whole cornea or the partial cornea (the endothelium alone is transplanted from the cadaver donor to the recipient with the endothelial disease [1]. In whole corneal or partial corneal transplant one cadaver donor's cornea can be used to treat one recipient cornea only, which leads to a huge global shortage of donor corneas [2]. At this juncture Yokoo et al isolated and expanded corneal endothelial precursors using the sphere forming assay in vitro [3] and demonstrated the in vivo transplantation of these corneal endothelial precursors in a rabbit model of bullous keratopathy [4]. Following this, we studied the transportation of cadaver donor derived corneal endothelial tissue (CET from human cadaver donors in a thermoreversible gelation polymer (TGP (4 based transportation cocktail without cool preservation and demonstrated the viability of human corneal endothelial precursor (HCEP cells isolated from these CETs even after 72 hours of transportation without cool preservation [5]. This was done to suit the conditions existing in developing nations like India where hospitals might be located far from eye banks and maintaining cold chain preservation is relatively difficult. Further, these HCEPs were expanded in vitro using a polymer based expansion protocol [5]. This was the first step in the realisation of the dream of 'Eye for eyes' in a manner suitable for Indian conditions. Corneal transplantation has been in routine practice to treat corneal endothelial diseases like Bullous Keratopathy, in which either the whole cornea or the partial cornea (the endothelium alone is transplanted from the cadaver donor to the recipient with the endothelial disease [1]. In whole corneal or partial corneal transplant one cadaver donor's cornea can be used to treat one recipient cornea only, which leads to a huge global

  2. Double peacock eye optical element for extended focal depth imaging with ophthalmic applications.

    Science.gov (United States)

    Romero, Lenny A; Millán, María S; Jaroszewicz, Zbigniew; Kolodziejczyk, Andrzej

    2012-04-01

    The aged human eye is commonly affected by presbyopia, and therefore, it gradually loses its capability to form images of objects placed at different distances. Extended depth of focus (EDOF) imaging elements can overcome this inability, despite the introduction of a certain amount of aberration. This paper evaluates the EDOF imaging performance of the so-called peacock eye phase diffractive element, which focuses an incident plane wave into a segment of the optical axis and explores the element's potential use for ophthalmic presbyopia compensation optics. Two designs of the element are analyzed: the single peacock eye, which produces one focal segment along the axis, and the double peacock eye, which is a spatially multiplexed element that produces two focal segments with partial overlapping along the axis. The performances of the peacock eye elements are compared with those of multifocal lenses through numerical simulations as well as optical experiments in the image space. The results demonstrate that the peacock eye elements form sharper images along the focal segment than the multifocal lenses and, therefore, are more suitable for presbyopia compensation. The extreme points of the depth of field in the object space, which represent the remote and the near object points, have been experimentally obtained for both the single and the double peacock eye optical elements. The double peacock eye element has better imaging quality for relatively short and intermediate distances than the single peacock eye, whereas the latter seems better for far distance vision.

  3. Rheumatoid Arthritis: Can It Affect the Eyes?

    Science.gov (United States)

    ... arthritis: Can it affect the eyes? Can rheumatoid arthritis affect the eyes? Answers from April Chang-Miller, M.D. Rheumatoid arthritis is a chronic inflammatory disease that primarily affects ...

  4. Eye Care: MedlinePlus Health Topic

    Science.gov (United States)

    ... of you for 20 seconds. Eye Tests and Exams Everyone needs to have their eyesight tested to ... an eye examination before entering nursing homes. Article: Caffeine metabolites not caffeine protect against riboflavin photosensitized oxidative ...

  5. Transpalpebral eye enucleation in the standing horse

    DEFF Research Database (Denmark)

    Christophersen, Mogens Teken

    Transpalpebral eye enucleation in the standing horse. The Nordic Equine Veterinary Conference, Proceedings, Copenhagen. Denmark. Nov. 2011.......Transpalpebral eye enucleation in the standing horse. The Nordic Equine Veterinary Conference, Proceedings, Copenhagen. Denmark. Nov. 2011....

  6. Prevention of sports-related eye injury.

    Science.gov (United States)

    Stock, J G; Cornell, F M

    1991-08-01

    Sports-related eye injury is an important cause of vision loss. Many eye injuries can be prevented through the supervision of play, the enforcement of game rules and the use of eye protective devices. State-of-the-art eye protective devices incorporate highly impact-resistant optical material, usually polycarbonate lenses, in a sturdy frame. Protective devices are available for use in racquet sports, baseball, basketball, football, ice hockey and other sports.

  7. Computer simulation of cellular patterning within the Drosophila pupal eye.

    Directory of Open Access Journals (Sweden)

    David E Larson

    Full Text Available We present a computer simulation and associated experimental validation of assembly of glial-like support cells into the interweaving hexagonal lattice that spans the Drosophila pupal eye. This process of cell movements organizes the ommatidial array into a functional pattern. Unlike earlier simulations that focused on the arrangements of cells within individual ommatidia, here we examine the local movements that lead to large-scale organization of the emerging eye field. Simulations based on our experimental observations of cell adhesion, cell death, and cell movement successfully patterned a tracing of an emerging wild-type pupal eye. Surprisingly, altering cell adhesion had only a mild effect on patterning, contradicting our previous hypothesis that the patterning was primarily the result of preferential adhesion between IRM-class surface proteins. Instead, our simulations highlighted the importance of programmed cell death (PCD as well as a previously unappreciated variable: the expansion of cells' apical surface areas, which promoted rearrangement of neighboring cells. We tested this prediction experimentally by preventing expansion in the apical area of individual cells: patterning was disrupted in a manner predicted by our simulations. Our work demonstrates the value of combining computer simulation with in vivo experiments to uncover novel mechanisms that are perpetuated throughout the eye field. It also demonstrates the utility of the Glazier-Graner-Hogeweg model (GGH for modeling the links between local cellular interactions and emergent properties of developing epithelia as well as predicting unanticipated results in vivo.

  8. Eye movements during visual search in patients with glaucoma

    Directory of Open Access Journals (Sweden)

    Smith Nicholas D

    2012-08-01

    Full Text Available Abstract Background Glaucoma has been shown to lead to disability in many daily tasks including visual search. This study aims to determine whether the saccadic eye movements of people with glaucoma differ from those of people with normal vision, and to investigate the association between eye movements and impaired visual search. Methods Forty patients (mean age: 67 [SD: 9] years with a range of glaucomatous visual field (VF defects in both eyes (mean best eye mean deviation [MD]: –5.9 (SD: 5.4 dB and 40 age-related people with normal vision (mean age: 66 [SD: 10] years were timed as they searched for a series of target objects in computer displayed photographs of real world scenes. Eye movements were simultaneously recorded using an eye tracker. Average number of saccades per second, average saccade amplitude and average search duration across trials were recorded. These response variables were compared with measurements of VF and contrast sensitivity. Results The average rate of saccades made by the patient group was significantly smaller than the number made by controls during the visual search task (P = 0.02; mean reduction of 5.6% (95% CI: 0.1 to 10.4%. There was no difference in average saccade amplitude between the patients and the controls (P = 0.09. Average number of saccades was weakly correlated with aspects of visual function, with patients with worse contrast sensitivity (PR logCS; Spearman’s rho: 0.42; P = 0.006 and more severe VF defects (best eye MD; Spearman’s rho: 0.34; P = 0.037 tending to make less eye movements during the task. Average detection time in the search task was associated with the average rate of saccades in the patient group (Spearman’s rho = −0.65; P  Conclusions The average rate of saccades made during visual search by this group of patients was fewer than those made by people with normal vision of a similar average age. There was wide variability in saccade rate in the patients

  9. BMP signaling protects telencephalic fate by repressing eye identity and its Cxcr4-dependent morphogenesis.

    Science.gov (United States)

    Bielen, Holger; Houart, Corinne

    2012-10-16

    Depletion of Wnt signaling is a major requirement for the induction of the anterior prosencephalon. However, the molecular events driving the differential regionalization of this area into eye-field and telencephalon fates are still unknown. Here we show that the BMP pathway is active in the anterior neural ectoderm during late blastula to early gastrula stage in zebrafish. Bmp2b mutants and mosaic loss-of-function experiments reveal that BMP acts as a repressor of eye-field fate through inhibition of its key transcription factor Rx3, thereby protecting the future telencephalon from acquiring eye identity. This BMP-driven mechanism initiates the establishment of the telencephalon prior to the involvement of Wnt antagonists from the anterior neural border. Furthermore, we demonstrate that Rx3 and BMP are respectively required to maintain and restrict the chemokine receptor cxcr4a, which in turn contributes to the morphogenetic separation of eye-field and telencephalic cells during early neurulation.

  10. Radiation oncology a physicist's-eye view

    CERN Document Server

    Goitein, Michael

    2007-01-01

    Radiation Oncology: A Physicist's-Eye View was written for both physicists and medical oncologists with the aim of helping them approach the use of radiation in the treatment of cancer with understanding, confidence, and imagination. The book will let practitioners in one field understand the problems of, and find solutions for, practitioners in the other. It will help them to know "why" certain approaches are fruitful while, at the same time, encouraging them to ask the question "Why not?" in the face of assertions that some proposal of theirs is impractical, unreasonable, or impossible. Unlike a textbook, formal and complete developments of the topics are not among the goals. Instead, the reader will develop a foundation for understanding what the author has found to be matters of importance in radiation oncology during over thirty years of experience. Presentations cover, in largely non-technical language, the principal physical and biological aspects of radiation treatment and address practical clinical c...

  11. Infant Eyes: A Window on Cognitive Development

    Science.gov (United States)

    Aslin, Richard N.

    2012-01-01

    Eye-trackers suitable for use with infants are now marketed by several commercial vendors. As eye-trackers become more prevalent in infancy research, there is the potential for users to be unaware of dangers lurking "under the hood" if they assume the eye-tracker introduces no errors in measuring infants' gaze. Moreover, the influx of voluminous…

  12. Trustworthy-looking face meets brown eyes.

    Directory of Open Access Journals (Sweden)

    Karel Kleisner

    Full Text Available We tested whether eye color influences perception of trustworthiness. Facial photographs of 40 female and 40 male students were rated for perceived trustworthiness. Eye color had a significant effect, the brown-eyed faces being perceived as more trustworthy than the blue-eyed ones. Geometric morphometrics, however, revealed significant correlations between eye color and face shape. Thus, face shape likewise had a significant effect on perceived trustworthiness but only for male faces, the effect for female faces not being significant. To determine whether perception of trustworthiness was being influenced primarily by eye color or by face shape, we recolored the eyes on the same male facial photos and repeated the test procedure. Eye color now had no effect on perceived trustworthiness. We concluded that although the brown-eyed faces were perceived as more trustworthy than the blue-eyed ones, it was not brown eye color per se that caused the stronger perception of trustworthiness but rather the facial features associated with brown eyes.

  13. Clinical light damage to the eye

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D.

    1987-01-01

    This book contains four sections: The Nature of Light and of Light Damage to Biological Tissues; Light Damage to the Eye; Protecting the Eye from Light Damage; and Overview of Light Damage to the Eye. Some of the paper titles are: Ultraviolet-Absorbing Intraocular Lens Implants; Phototoxic Changes in the Retina; Light Damage to the Lens; and Radiation, Light, and Sight.

  14. Eye Gaze in Creative Sign Language

    Science.gov (United States)

    Kaneko, Michiko; Mesch, Johanna

    2013-01-01

    This article discusses the role of eye gaze in creative sign language. Because eye gaze conveys various types of linguistic and poetic information, it is an intrinsic part of sign language linguistics in general and of creative signing in particular. We discuss various functions of eye gaze in poetic signing and propose a classification of gaze…

  15. Trustworthy-looking face meets brown eyes.

    Science.gov (United States)

    Kleisner, Karel; Priplatova, Lenka; Frost, Peter; Flegr, Jaroslav

    2013-01-01

    We tested whether eye color influences perception of trustworthiness. Facial photographs of 40 female and 40 male students were rated for perceived trustworthiness. Eye color had a significant effect, the brown-eyed faces being perceived as more trustworthy than the blue-eyed ones. Geometric morphometrics, however, revealed significant correlations between eye color and face shape. Thus, face shape likewise had a significant effect on perceived trustworthiness but only for male faces, the effect for female faces not being significant. To determine whether perception of trustworthiness was being influenced primarily by eye color or by face shape, we recolored the eyes on the same male facial photos and repeated the test procedure. Eye color now had no effect on perceived trustworthiness. We concluded that although the brown-eyed faces were perceived as more trustworthy than the blue-eyed ones, it was not brown eye color per se that caused the stronger perception of trustworthiness but rather the facial features associated with brown eyes.

  16. Experiencing Light's Properties within Your Own Eye

    Science.gov (United States)

    Mauser, Michael

    2011-01-01

    Seeing the reflection, refraction, dispersion, absorption, polarization, and scattering or diffraction of light within your own eye makes these properties of light truly personal. There are practical aspects of these within the eye phenomena, such as eye tracking for computer interfaces. They also offer some intriguing diversions, for example,…

  17. A Model of the Human Eye

    Science.gov (United States)

    Colicchia, G.; Wiesner, H.; Waltner, C.; Zollman, D.

    2008-01-01

    We describe a model of the human eye that incorporates a variable converging lens. The model can be easily constructed by students with low-cost materials. It shows in a comprehensible way the functionality of the eye's optical system. Images of near and far objects can be focused. Also, the defects of near and farsighted eyes can be demonstrated.

  18. Eye Gaze in Creative Sign Language

    Science.gov (United States)

    Kaneko, Michiko; Mesch, Johanna

    2013-01-01

    This article discusses the role of eye gaze in creative sign language. Because eye gaze conveys various types of linguistic and poetic information, it is an intrinsic part of sign language linguistics in general and of creative signing in particular. We discuss various functions of eye gaze in poetic signing and propose a classification of gaze…

  19. Advances in Eye Tracking in Infancy Research

    Science.gov (United States)

    Oakes, Lisa M.

    2012-01-01

    In 2004, McMurray and Aslin edited for "Infancy" a special section on eye tracking. The articles in that special issue revealed the enormous promise of automatic eye tracking with young infants and demonstrated that eye-tracking procedures can provide significant insight into the emergence of cognitive, social, and emotional processing in infancy.…

  20. Cytological examination of pink eye afflicted tubers

    Science.gov (United States)

    Pink eye is a tuber disorder of undetermined cause that can result in serious processing complications and storage losses throughout North America. Pink eye symptoms progress from ephemeral light pink colorations around bud-end eyes to water-soaked or dried and cracked “corky-patch” periderm. Late s...

  1. Advances in Eye Tracking in Infancy Research

    Science.gov (United States)

    Oakes, Lisa M.

    2012-01-01

    In 2004, McMurray and Aslin edited for "Infancy" a special section on eye tracking. The articles in that special issue revealed the enormous promise of automatic eye tracking with young infants and demonstrated that eye-tracking procedures can provide significant insight into the emergence of cognitive, social, and emotional processing in infancy.…

  2. The Tehran Eye Study: research design and eye examination protocol

    Directory of Open Access Journals (Sweden)

    Fotouhi Akbar

    2003-07-01

    Full Text Available Abstract Background Visual impairment has a profound impact on society. The majority of visually impaired people live in developing countries, and since most disorders leading to visual impairment are preventable or curable, their control is a priority in these countries. Considering the complicated epidemiology of visual impairment and the wide variety of factors involved, region specific intervention strategies are required for every community. Therefore, providing appropriate data is one of the first steps in these communities, as it is in Iran. The objectives of this study are to describe the prevalence and causes of visual impairment in the population of Tehran city; the prevalence of refractive errors, lens opacity, ocular hypertension, and color blindness in this population, and also the familial aggregation of refractive errors, lens opacity, ocular hypertension, and color blindness within the study sample. Methods Design Through a population-based, cross-sectional study, a total of 5300 Tehran citizens will be selected from 160 clusters using a stratified cluster random sampling strategy. The eligible people will be enumerated through a door-to-door household survey in the selected clusters and will be invited. All participants will be transferred to a clinic for measurements of uncorrected, best corrected and presenting visual acuity; manifest, subjective and cycloplegic refraction; color vision test; Goldmann applanation tonometry; examination of the external eye, anterior segment, media, and fundus; and an interview about demographic characteristics and history of eye diseases, eye trauma, diabetes mellitus, high blood pressure, and ophthalmologic cares. The study design and eye examination protocol are described. Conclusion We expect that findings from the TES will show the status of visual problems and their causes in the community. This study can highlight the people who should be targeted by visual impairment prevention programs.

  3. Multiple Eyes for the VLT

    Science.gov (United States)

    2002-01-01

    First System of Deployable Multi-Integral Field Units Ready Summary The ESO Very Large Telescope (VLT) at the Paranal Observatory is being equipped with many state-of-the-art astronomical instruments that will allow observations in a large number of different modes and wavebands. Soon to come is the Fibre Large Array Multi-Element Spectrograph (FLAMES) , a project co-ordinated by ESO. It incorporates several complex components, now being constructed at various research institutions in Europe and Australia. One of these, a true technological feat, is a unique system of 15 deployable fibre bundles, the so-called Integral Field Units (IFUs) . They can be accurately positioned within a sky field-of-view measuring no less that 25 arcmin in diameter, i.e., almost as large as the full Moon . Each of the IFUs looks like an insect's eye and images a small sky area (3 x 2 arcsec 2 ) with a multiple microlens. From each IFU, 20 narrow light beams are sent via optical fibres to an advanced spectrograph. All 300 spectra are recorded simultaneously by a sensitive digital camera. A major advantage of this technique is that, contrary usual spectroscopic observations in which spectral information is obtained along a (one-dimensional) line on the sky, it now allows (two-dimensional) area spectroscopy . This will permit extremely efficient spectral observations of many celestial objects, including faint galaxies, providing detailed information about their internal structure and motions. Such studies will have an important impact on our understanding, e.g., of the early evolution of galaxies , the main building blocks in the Universe. The IFUs have been developed by a team of astronomers and engineers [2] at the Observatoire de Paris-Meudon. All IFU components are now at the ESO Headquarters in Garching (Germany) where they are being checked and integrated into the instrument [3]. PR Photo 03a/02 : The GIRAFFE spectrograph in the ESO Assembly Hall (Garching, Germany) . PR Photo 03b/02

  4. In the Eye of the Beholder-  A Survey of Models for Eyes and Gaze

    DEFF Research Database (Denmark)

    Witzner Hansen, Dan; Ji, Qiang

    2010-01-01

    Despite active research and significant progress in the last 30 years, eye detection and tracking remains challenging due to the individuality of eyes, occlusion, variability in scale, location, and light conditions. Data on eye location and details of eye movements have numerous applications...

  5. The eye and its diseases in Ancient Egypt

    DEFF Research Database (Denmark)

    Andersen, S. Ry

    1997-01-01

    Ophthalmology, History of ophthalmology, eyes in the Ancient Egypt, eye disease in Ancient Egypt, porotic hyperostosis, mummification......Ophthalmology, History of ophthalmology, eyes in the Ancient Egypt, eye disease in Ancient Egypt, porotic hyperostosis, mummification...

  6. Ten Ways to Prevent Eye Injuries at Work

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  7. How Often Should I Have an Eye Exam?

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  8. Roles of eyes, leg proprioceptors and statocysts in the compensatory eye movements of freely walking land crabs (Cardisoma guanhumi)

    Science.gov (United States)

    Paul; Barnes; Varju

    1998-12-01

    The compound eyes, the canal organs of the statocysts and proprioceptors in the legs all generate compensatory eye movements in the horizontal plane in the land crab Cardisoma guanhumi. Frequency analyses of the compensatory eye reflexes elicited by each of these inputs show that visual (V) and proprioceptive (P) reflexes respond best below 0.1 Hz, while statocyst (S) reflexes only achieve a high gain above this frequency. They thus increase the range of frequencies over which compensation can occur. Eye and body movements were recorded in an arena under all possible combinations of crabs seeing or blind (V+ or V-), with or without statocysts (S+ or S-) and freely walking or passively transported on a trolley (P+ or P-). Intact crabs (V+S+P+) show good stabilisation of the eyes in space, the only movements with respect to external coordinates being saccadic resetting movements (fast phases of nystagmus). The eyes thus compensate well for body turns, but are unaffected by translatory movements of the body and turns that are not accompanied by a change in the orientation of the long axis of the body in space. In the absence of any one sense, compensation for rotation is significantly impaired, whether measured by the increase in the width of the histograms of changes in the angular positions of the eyes in space ( capdelta &phgr; E), by the mean angular velocity of the eyes (slope of regression line, mE) with respect to the angular velocity of the body (mB) or by response gain plotted against angular acceleration of body turn (a). The absence of two senses reduces the crab's ability to compensate still further, with the statocyst-only condition (V-S+P-) being little better than the condition when all three senses are absent (V-S-P-).Such multisensory control of eye compensation for body rotation is discussed both in terms of making use of every available cue for reducing retinal slip and in making available the information content of the optic flow field.

  9. Effect of eye patching in rehabilitation of neglect

    Directory of Open Access Journals (Sweden)

    Nicola eSmania

    2013-09-01

    Full Text Available Eye patching (monocular or right hemifield has been proposed to improve visuospatial attention to the ignored field in patients with neglect. The aim of this paper is to review the literature on the effects of eye patching in hemispatial neglect after stroke in order to convey evidence-based recommendations to clinicians in stroke rehabilitation. Thirteen intervention studies were selected from the Medline, EMBASE, Scopus, Cochrane Library, CINAHL, PsychINFO, EBRSR and Health Star databases. Methodological quality was defined according to the Physiotherapy Evidence Database. Overall, seven studies used monocular eye patching, five used right hemifield patching and one compared right monocular with right hemifield patching. Seven studies compared normal viewing to monocular or hemifield patching conditions. Six studies included a period of treatment. Three studies included follow-up evaluations. As to the monocular eye patching, four studies reported positive effects of right monocular patching. One study showed an improvement in hemispatial neglect with left monocular patching. Two studies found no superiority of right versus left monocular patching. One study found no effects of right monocular patching. As to the right hemifield eye patching, one study showed improvements in neglect after right hemifield patching. Three studies found that right hemifield patching combined with another rehabilitation technique was more effective than that treatment alone. One study found no differences between right hemifield patching combined with another treatment and that treatment alone. One study found the same effect between right hemifield patching alone and another rehabilitation technique.Our results globally tend to support the usefulness of right hemifield eye patching in clinical practice. In order to define a level of evidence with the standard rehabilitation evidence rating tools, further properly powered randomized controlled trials or meta

  10. Tromsø eye study

    DEFF Research Database (Denmark)

    Bertelsen, Geir; Peto, Tunde; Lindekleiv, Haakon;

    2013-01-01

    Purpose:  To determine the prevalence of visual impairment, retinopathy and macular oedema, and assess risk factors for retinopathy in persons with diabetes. Methods:  The present study included 514 participants with diabetes aged 46-87 years from the Tromsø Eye Study, a sub-study of the population......-based Tromsø Study in Norway. Visual acuity was measured using an auto-refractor. Retinal images from both eyes were graded for retinopathy and macular oedema. We collected data on risk factor exposure from self-report questionnaires, clinical examinations, laboratory measurements and case note reviews....... Regression models assessed the cross-sectional relationship between potential risk factors and diabetic retinopathy. Results:  The prevalence of visual impairment (corrected Snellen visual acuity...

  11. Management of thyroid eye disease

    Energy Technology Data Exchange (ETDEWEB)

    Bartalena, Luigi; Tanda, Maria Laura [Department of Endocrinology, University of Insubria, Ospedale di Circolo, Viale Borri, 57, 21100 Varese (Italy); Marcocci, Claudio; Pinchera, Aldo [Department of Endocrinology and Metabolism, University of Pisa, Pisa (Italy)

    2002-08-01

    Thyroid eye disease (TED) is the most frequent extrathyroidal manifestation of Graves' disease. In most instances it is mild and non-progressive, but in 3%-5% of cases it is severe. Non-severe TED requires only supportive measures, such as eye ointments, sunglasses and prisms. By contrast, severe TED requires aggressive treatment, either medical (high-dose glucocorticoids, orbital radiotherapy) or surgical (orbital decompression). The choice of treatment relies on the assessment of both TED severity and activity. Removal of controllable risk factors, especially cigarette smoking, is important to improve the course and the therapeutic outcome. A coordinated approach to the treatment of hyperthyroidism and TED is also required. Novel promising treatments, to be verified in large series of patients, include somatostatin analogues and cytokine antagonists. (orig.)

  12. Flavonoid intake and eye health.

    Science.gov (United States)

    Milbury, Paul E

    2012-01-01

    In the modern era of evidence-based scientific medicine, there is little recognition of centuries of shaman observational evidence. Yet it is extremely difficult to conduct long duration controlled studies of large populations. The controversy surrounding the issue of flavonoid bioactivity and alleged benefits for eye health is also plagued by natural product industry marketing efforts that rely on small, often poorly designed studies. Ample laboratory evidence exists from in vitro and in vivo studies that provide plausible mechanistic evidence for flavonoid interactions relevant to visual function. Lacking are large randomized double-blind placebo-controlled studies in older subjects who have early signs of vision impairment. These studies could link flavonoid intake and bioavailability to efficacy in prevention of age related vision disorders that develop over decades. Support for clinical trials remains to be found before a full "recommendation" can be made regarding the value of diets high in flavonoids for eye health.

  13. Rabbits' eye globe sonographic biometry.

    Science.gov (United States)

    Toni, Maria Carolina; Meirelles, Adriana Érica Wilkes Burton; Gava, Fábio Nelson; Camacho, Aparecido Antônio; Laus, José Luiz; Canola, Júlio Carlos

    2010-11-01

    To measure intraocular structures in New Zealand White breed rabbits (Oryctolagus cuniculus Linnaeus, 1758) using A-mode and B-mode ultrasound with a 20 MHz transducer. In this study, the eyes of 15 rabbits were evaluated for determination of intraocular measurements using an ophthalmic ultrasound unit able to operate in both A and B-modes. The distances from the cornea to the anterior capsule of the lens (D1), from the anterior capsule of the lens to the posterior capsule of the lens (D2), from the posterior capsule of the lens to the retina (D3) and the complete length of the eye, which corresponds to the distance from the cornea to the retina (D4) were taken. The mean values obtained were 2.70 mm (± 0.22 mm) for D1, 7.32 mm (± 0.40 mm) for D2, 7.10 mm (± 0.45 mm) for D3 and 17.12 mm (± 0.41 mm) for D4. Statistical analyses using the Student's t-test showed that there were no differences between the eyes. The study was feasible without the need of pharmacological restraint and yielded normal mean values for ocular sonographic biometry in rabbits. © 2010 American College of Veterinary Ophthalmologists.

  14. Eye Formation in Rotating Convection

    CERN Document Server

    Oruba, L; Dormy, E

    2016-01-01

    We consider rotating convection in a shallow, cylindrical domain. We examine the conditions under which the resulting vortex develops an eye at its core; that is, a region where the poloidal flow reverses and the angular momentum is low. For simplicity, we restrict ourselves to steady, axisymmetric flows in a Boussinesq fluid. Our numerical experiments show that, in such systems, an eye forms as a passive response to the development of a so-called eyewall, a conical annulus of intense, negative azimuthal vorticity that can form near the axis and separates the eye from the primary vortex. We also observe that the vorticity in the eyewall comes from the lower boundary layer, and relies on the fact the poloidal flow strips negative vorticity out of the boundary layer and carries it up into the fluid above as it turns upward near the axis. This process is effective only if the Reynolds number is sufficiently high for the advection of vorticity to dominate over diffusion. Finally we observe that, in the vicinity o...

  15. Metabolic syndrome and eye diseases.

    Science.gov (United States)

    Poh, Stanley; Mohamed Abdul, Riswana Banu Binte; Lamoureux, Ecosse L; Wong, Tien Y; Sabanayagam, Charumathi

    2016-03-01

    Metabolic syndrome is becoming a worldwide medical and public health challenge as it has been seen increasing in prevalence over the years. Age-related eye diseases, the leading cause of blindness globally and visual impairment in developed countries, are also on the rise due to aging of the population. Many of the individual components of the metabolic syndrome have been shown to be associated with these eye diseases. However, the association of metabolic syndrome with eye diseases is not clear. In this review, we reviewed the evidence for associations between metabolic syndrome and certain ocular diseases in populations. We also reviewed the association of individual metabolic syndrome components with ocular diseases due to a paucity of research in this area. Besides, we also summarised the current understanding of etiological mechanisms of how metabolic syndrome or the individual components lead to these ocular diseases. With increasing evidence of such associations, it may be important to identify patients who are at risk of developing metabolic syndrome as prompt treatment and intervention may potentially decrease the risk of developing certain ocular diseases.

  16. Eye tracking disturbances in Schizophrenia

    Directory of Open Access Journals (Sweden)

    Sharma Pradeep

    2000-01-01

    Full Text Available Purpose: To study the frequency of different types of eye tracking disturbances in schizophrenia. Materials and Methods: Smooth pursuit eye movements were studied by electro-oculography (EOG in 22 schizophrenic patients (ICD-10 criteria and 15 age and sex-matched controls. The studied parameters included average pursuit gain, number of saccades, the frequency of different types of saccades (catch-up, back-up, anticipatory saccades, and disturbances during fixation. The results were analysed statistically. Results: The average pursuit gain was significantly affected in patients for target velocity of 30°/sec (p=0.007. The catch-up and back-up saccades were more common in cases than controls but the difference was not significant (p=0.39 and 0.36 respectively. The anticipatory saccades were significantly more frequent in cases than controls (p<0.0001 for both 15°/sec and 30°/sec target velocities. This was also correlated with the duration of illness. Conclusion: Anticipatory saccades are significantly more frequent during eye tracking in schizophrenia and appear to be an objective marker for the disease.

  17. Eye movements and information geometry.

    Science.gov (United States)

    Lenz, Reiner

    2016-08-01

    The human visual system uses eye movements to gather visual information. They act as visual scanning processes and can roughly be divided into two different types: small movements around fixation points and larger movements between fixation points. The processes are often modeled as random walks, and recent models based on heavy tail distributions, also known as Levý flights, have been used in these investigations. In contrast to these approaches we do not model the stochastic processes, but we will show that the step lengths of the movements between fixation points follow generalized Pareto distributions (GPDs). We will use general arguments from the theory of extreme value statistics to motivate the usage of the GPD and show empirically that the GPDs provide good fits for measured eye tracking data. In the framework of information geometry the GPDs with a common threshold form a two-dimensional Riemann manifold with the Fisher information matrix as a metric. We compute the Fisher information matrix for the GPDs and introduce a feature vector describing a GPD by its parameters and different geometrical properties of its Fisher information matrix. In our statistical analysis we use eye tracker measurements in a database with 15 observers viewing 1003 images under free-viewing conditions. We use Matlab functions with their standard parameter settings and show that a naive Bayes classifier using the eigenvalues of the Fisher information matrix provides a high classification rate identifying the 15 observers in the database.

  18. Materials for occupational eye protectors.

    Science.gov (United States)

    Dain, Stephen J

    2012-03-01

    The selection of lens materials for non-prescription personal protective equipment has been a relatively simple process and has its origins in many studies around the 1970s. The viable materials available at that time were tempered glass, hard resin (n = 1.50) and polycarbonate. The modern spectacle non-prescription eye protector of choice is inevitably hard coated polycarbonate, which has exemplary impact resistant properties. In the prescription lens area, there is a bewildering array of materials of various refractive indices with a variety of coatings. The selection of an ophthalmic lens has optical and cosmetic considerations ahead of impact resistance. In complying with the Australian/New Zealand standard on prescription eye protection, adequate impact resistance must rate as the foremost requirement, with optical and cosmetic considerations as important but lesser considerations. In this review, the evidence on impact resistance of the available materials is presented, the standards set for testing impact resistance are detailed and some guidance is provided for the selection of prescription eye protection materials.

  19. Mitochondrial disorders and the eye

    Directory of Open Access Journals (Sweden)

    O’Neill EC

    2011-09-01

    Full Text Available Nicole J Van Bergen, Rahul Chakrabarti, Evelyn C O'Neill, Jonathan G Crowston, Ian A TrounceCentre for Eye Research Australia, Department of Ophthalmology, University of Melbourne, Victoria, AustraliaAbstract: The clinical significance of disturbed mitochondrial function in the eye has emerged since mitochondrial DNA (mtDNA mutation was described in Leber's hereditary optic neuropathy. The spectrum of mitochondrial dysfunction has become apparent through increased understanding of the contribution of nuclear and somatic mtDNA mutations to mitochondrial dynamics and function. Common ophthalmic manifestations of mitochondrial dysfunction include optic atrophy, pigmentary retinopathy, and ophthalmoplegia. The majority of patients with ocular manifestations of mitochondrial disease also have variable central and peripheral nervous system involvement. Mitochondrial dysfunction has recently been associated with age-related retinal disease including macular degeneration and glaucoma. Therefore, therapeutic targets directed at promoting mitochondrial biogenesis and function offer a potential to both preserve retinal function and attenuate neurodegenerative processes.Keywords: mitochondria, disease, retina, eye, aging, neuroprotection

  20. An eye model for uncalibrated eye gaze estimation under variable head pose

    Science.gov (United States)

    Hnatow, Justin; Savakis, Andreas

    2007-04-01

    Gaze estimation is an important component of computer vision systems that monitor human activity for surveillance, human-computer interaction, and various other applications including iris recognition. Gaze estimation methods are particularly valuable when they are non-intrusive, do not require calibration, and generalize well across users. This paper presents a novel eye model that is employed for efficiently performing uncalibrated eye gaze estimation. The proposed eye model was constructed from a geometric simplification of the eye and anthropometric data about eye feature sizes in order to circumvent the requirement of calibration procedures for each individual user. The positions of the two eye corners and the midpupil, the distance between the two eye corners, and the radius of the eye sphere are required for gaze angle calculation. The locations of the eye corners and midpupil are estimated via processing following eye detection, and the remaining parameters are obtained from anthropometric data. This eye model is easily extended to estimating eye gaze under variable head pose. The eye model was tested on still images of subjects at frontal pose (0 °) and side pose (34 °). An upper bound of the model's performance was obtained by manually selecting the eye feature locations. The resulting average absolute error was 2.98 ° for frontal pose and 2.87 ° for side pose. The error was consistent across subjects, which indicates that good generalization was obtained. This level of performance compares well with other gaze estimation systems that utilize a calibration procedure to measure eye features.

  1. Preference for human eyes in human infants.

    Science.gov (United States)

    Dupierrix, Eve; de Boisferon, Anne Hillairet; Méary, David; Lee, Kang; Quinn, Paul C; Di Giorgio, Elisa; Simion, Francesca; Tomonaga, Masaki; Pascalis, Olivier

    2014-07-01

    Despite evidence supporting an early attraction to human faces, the nature of the face representation in neonates and its development during the first year after birth remain poorly understood. One suggestion is that an early preference for human faces reflects an attraction toward human eyes because human eyes are distinctive compared with other animals. In accord with this proposal, prior empirical studies have demonstrated the importance of the eye region in face processing in adults and infants. However, an attraction for the human eye has never been shown directly in infants. The current study aimed to investigate whether an attraction for human eyes would be present in newborns and older infants. With the use of a preferential looking time paradigm, newborns and 3-, 6-, 9-, and 12-month-olds were simultaneously presented with a pair of nonhuman primate faces (chimpanzees and Barbary macaques) that differed only by the eyes, thereby pairing a face with original nonhuman primate eyes with the same face in which the eyes were replaced by human eyes. Our results revealed that no preference was observed in newborns, but a preference for nonhuman primate faces with human eyes emerged from 3months of age and remained stable thereafter. The findings are discussed in terms of how a preference for human eyes may emerge during the first few months after birth.

  2. Abnormal Fixational Eye Movements in Amblyopia.

    Science.gov (United States)

    Shaikh, Aasef G; Otero-Millan, Jorge; Kumar, Priyanka; Ghasia, Fatema F

    2016-01-01

    Fixational saccades shift the foveal image to counteract visual fading related to neural adaptation. Drifts are slow eye movements between two adjacent fixational saccades. We quantified fixational saccades and asked whether their changes could be attributed to pathologic drifts seen in amblyopia, one of the most common causes of blindness in childhood. Thirty-six pediatric subjects with varying severity of amblyopia and eleven healthy age-matched controls held their gaze on a visual target. Eye movements were measured with high-resolution video-oculography during fellow eye-viewing and amblyopic eye-viewing conditions. Fixational saccades and drifts were analyzed in the amblyopic and fellow eye and compared with controls. We found an increase in the amplitude with decreased frequency of fixational saccades in children with amblyopia. These alterations in fixational eye movements correlated with the severity of their amblyopia. There was also an increase in eye position variance during drifts in amblyopes. There was no correlation between the eye position variance or the eye velocity during ocular drifts and the amplitude of subsequent fixational saccade. Our findings suggest that abnormalities in fixational saccades in amblyopia are independent of the ocular drift. This investigation of amblyopia in pediatric age group quantitatively characterizes the fixation instability. Impaired properties of fixational saccades could be the consequence of abnormal processing and reorganization of the visual system in amblyopia. Paucity in the visual feedback during amblyopic eye-viewing condition can attribute to the increased eye position variance and drift velocity.

  3. Occupational eye dose in interventional cardiology procedures.

    Science.gov (United States)

    Haga, Yoshihiro; Chida, Koichi; Kaga, Yuji; Sota, Masahiro; Meguro, Taiichiro; Zuguchi, Masayuki

    2017-04-03

    It is important to measure the radiation dose [3-mm dose equivalent, Hp(3)] in the eye. This study was to determine the current occupational radiation eye dose of staff conducting interventional cardiology procedures, using a novel direct eye dosimeter. We measured the occupational eye dose [Hp(3)] in physicians and nurses in a catheterization laboratory for 6-months. The eye doses [Hp(3)] of 12 physicians (9 with Pb glasses, 3 without), and 11 nurses were recorded using a novel direct eye dosimeter, the DOSIRIS(TM). We placed dosimeters above and under the glasses. We also estimated the eye dose [0.07-mm dose equivalent] using a neck personal dosimeter. The eye doses among interventional staff ranked in the following order: physicians without Pb glasses > physicians with Pb glasses > nurses. The shielding effect of the glasses (0.07-mm Pb) in a clinical setting was approximately 60%. In physicians who do not wear Pb glasses, the eye dose may exceed the new regulatory limit for IR staff. We found good correlations between the neck dosimeter dose and eye dosimeter dose (inside or outside glasses, R(2) = 0.93 and R(2) = 0.86, respectively) in physicians. We recommend that interventional physicians use an eye dosimeter for correct evaluation of the lens dose.

  4. Eye tracking and the translation process

    DEFF Research Database (Denmark)

    Hvelplund, Kristian Tangsgaard

    2014-01-01

    Eye tracking has become increasingly popular as a quantitative research method in translation research. This paper discusses some of the major methodological issues involved in the use of eye tracking in translation research. It focuses specifically on challenges in the analysis and interpretation...... of eye-tracking data as reflections of cognitive processes during translation. Four types of methodological issues are discussed in the paper. The first part discusses the preparatory steps that precede the actual recording of eye-tracking data. The second part examines critically the general assumptions...... linking eye movements to cognitive processing in the context of translation research. The third part of the paper discusses two popular eye-tracking measures often used in translation research, fixations and pupil size, while the fourth part proposes a method to evaluate the quality of eye-tracking data....

  5. Reconstruction of eye movements during blinks

    CERN Document Server

    Baptista, M S; Kliegl, R; Engbert, R; Kurths, J

    2008-01-01

    In eye movement research in reading, the amount of data plays a crucial role for the validation of results. A methodological problem for the analysis of the eye movement in reading are blinks, when readers close their eyes. Blinking rate increases with increasing reading time, resulting in high data losses, especially for older adults or reading impaired subjects. We present a method, based on the symbolic sequence dynamics of the eye movements, that reconstructs the horizontal position of the eyes while the reader blinks. The method makes use of an observed fact that the movements of the eyes before closing or after opening contain information about the eyes movements during blinks. Test results indicate that our reconstruction method is superior to methods that use simpler interpolation approaches. In addition, analyses of the reconstructed data show no significant deviation from the usual behavior observed in readers.

  6. Eye tracking and the translation process

    DEFF Research Database (Denmark)

    Hvelplund, Kristian Tangsgaard

    2014-01-01

    Eye tracking has become increasingly popular as a quantitative research method in translation research. This paper discusses some of the major methodological issues involved in the use of eye tracking in translation research. It focuses specifically on challenges in the analysis and interpretation...... of eye-tracking data as reflections of cognitive processes during translation. Four types of methodological issues are discussed in the paper. The first part discusses the preparatory steps that precede the actual recording of eye-tracking data. The second part examines critically the general assumptions...... linking eye movements to cognitive processing in the context of translation research. The third part of the paper discusses two popular eye-tracking measures often used in translation research, fixations and pupil size, while the fourth part proposes a method to evaluate the quality of eye-tracking data....

  7. GRBs and Lobster Eye X-Ray Telescopes

    Science.gov (United States)

    Hudec, R.; Pina, L.; Marsikova, V.; Inneman, A.

    2013-07-01

    A large majority of GRBs exhibit X-ray emission. In addition, a dedicated separate group of GRB, the XRFs, exists which emission dominates in the X-ray spectral range. And the third group of GRB related objects (yet hypothetical) are the group of off-axis observed GRBs (orphan afterglows). These facts justify the consideration of an independent experiment for monitoring, detection and analyses of GRBs and others fast X-ray transients in X-rays. We will present and discuss such experiment based on wide-field X-ray telescopes of Lobster Eye type. We show that the wide field and fine sensitivity of Lobster Eye X-ray All-Sky Monitor make such instruments important tools in study of GRBs.

  8. Eye-safe laser glass development at SCHOTT

    Science.gov (United States)

    Li, Hong; Davis, Mark J.; Urruti, Eric H.

    2010-04-01

    SCHOTT has developed eye-safe laser glasses for laser range finder and medical/ biophotonics applications. The development described herein covers various combinations of key ions, Er, Yb, and Cr, with and without Ce, at controlled ratios and their perspective reduction - oxidation (REDOX) states to improve glass lasing, thermal lensing, and thermo-mechanical stability for field-based applications under high repetition rate operation. This report covers glass property characterizations and selective modeling results using statistically designed compositions.

  9. Research of the Exploitation of Human Resources in Blind Prevention and Primary Eye Care

    Institute of Scientific and Technical Information of China (English)

    JingxianWei; YonglongZhao

    1995-01-01

    Purpose:This research studied how to establish a relatively advanced blindness prevention and eye care cause in economically underdeveloped countryside.Methods:Ophthalmic vocational schools and professional lectures were held to train“practical type”primary eye care workers for the coumtryside.Further study in high-level(above provincial)hospitals was taken to train blindness preention &eye care backbones and leaders.Results:In 1986,the ratio of the number of the eye care workers of all levels to the number of the whole population in the prefecture was1:26000.In1992,it roseto1:17000.Aneye care network of 222stations had been established in tb countryside.Ten in the 13county hospitals had a seperated ophthalmology ed- partment,in which 3were awarded“National advanced blindness prevention County”.Twenty one hospitals were appointed as the Unit of Surgical Vision-Rehabilitation of Cataract.Blindness prevention and eye care convered1000000population(eye care avaliable within 5kilometers),23.5%of the whol popula-tion.Conclusions:In a demographically large but economically underdexeloped country-side area,the key to wide-range blindness prevention and eye oare is to exploti human resources effectively.We should train“Practical type”primary eye care workers,and have a number of edpartment leaders who are authoritive,influential in this field and ready to sacrifice to this cause.

  10. Teachers' Experiences of Using Eye Gaze-Controlled Computers for Pupils with Severe Motor Impairments and without Speech

    Science.gov (United States)

    Rytterström, Patrik; Borgestig, Maria; Hemmingsson, Helena

    2016-01-01

    The purpose of this study is to explore teachers' experiences of using eye gaze-controlled computers with pupils with severe disabilities. Technology to control a computer with eye gaze is a fast growing field and has promising implications for people with severe disabilities. This is a new assistive technology and a new learning situation for…

  11. Creation of nano eye-drops and effective drug delivery to the interior of the eye

    Science.gov (United States)

    Ikuta, Yoshikazu; Aoyagi, Shigenobu; Tanaka, Yuji; Sato, Kota; Inada, Satoshi; Koseki, Yoshitaka; Onodera, Tsunenobu; Oikawa, Hidetoshi; Kasai, Hitoshi

    2017-03-01

    Nano eye-drops are a new type of ophthalmic treatment with increased potency and reduced side effects. Compounds in conventional eye-drops barely penetrate into the eye because the cornea, located at the surface of eye, has a strong barrier function for preventing invasion of hydrophilic or large-sized materials from the outside. In this work, we describe the utility of nano eye-drops utilising brinzolamide, a commercially available glaucoma treatment drug, as a target compound. Fabrication of the nanoparticles of brinzolamide prodrug increases the eye penetration rate and results in high drug efficacy, compared with that of commercially available brinzolamide eye-drops formulated as micro-sized structures. In addition, the resulting nano eye-drops were not toxic to the corneal epithelium after repeated administration for 1 week. The nano eye-drops may have applications as a next-generation ophthalmic treatment.

  12. A study of artificial eyes for the measurement of precision in eye-trackers.

    Science.gov (United States)

    Wang, Dong; Mulvey, Fiona B; Pelz, Jeff B; Holmqvist, Kenneth

    2016-07-06

    The precision of an eye-tracker is critical to the correct identification of eye movements and their properties. To measure a system's precision, artificial eyes (AEs) are often used, to exclude eye movements influencing the measurements. A possible issue, however, is that it is virtually impossible to construct AEs with sufficient complexity to fully represent the human eye. To examine the consequences of this limitation, we tested currently used AEs from three manufacturers of eye-trackers and compared them to a more complex model, using 12 commercial eye-trackers. Because precision can be measured in various ways, we compared different metrics in the spatial domain and analyzed the power-spectral densities in the frequency domain. To assess how precision measurements compare in artificial and human eyes, we also measured precision using human recordings on the same eye-trackers. Our results show that the modified eye model presented can cope with all eye-trackers tested and acts as a promising candidate for further development of a set of AEs with varying pupil size and pupil-iris contrast. The spectral analysis of both the AE and human data revealed that human eye data have different frequencies that likely reflect the physiological characteristics of human eye movements. We also report the effects of sample selection methods for precision calculations. This study is part of the EMRA/COGAIN Eye Data Quality Standardization Project.

  13. Monocular tool control, eye dominance, and laterality in New Caledonian crows.

    Science.gov (United States)

    Martinho, Antone; Burns, Zackory T; von Bayern, Auguste M P; Kacelnik, Alex

    2014-12-15

    Tool use, though rare, is taxonomically widespread, but morphological adaptations for tool use are virtually unknown. We focus on the New Caledonian crow (NCC, Corvus moneduloides), which displays some of the most innovative tool-related behavior among nonhumans. One of their major food sources is larvae extracted from burrows with sticks held diagonally in the bill, oriented with individual, but not species-wide, laterality. Among possible behavioral and anatomical adaptations for tool use, NCCs possess unusually wide binocular visual fields (up to 60°), suggesting that extreme binocular vision may facilitate tool use. Here, we establish that during natural extractions, tool tips can only be viewed by the contralateral eye. Thus, maintaining binocular view of tool tips is unlikely to have selected for wide binocular fields; the selective factor is more likely to have been to allow each eye to see far enough across the midsagittal line to view the tool's tip monocularly. Consequently, we tested the hypothesis that tool side preference follows eye preference and found that eye dominance does predict tool laterality across individuals. This contrasts with humans' species-wide motor laterality and uncorrelated motor-visual laterality, possibly because bill-held tools are viewed monocularly and move in concert with eyes, whereas hand-held tools are visible to both eyes and allow independent combinations of eye preference and handedness. This difference may affect other models of coordination between vision and mechanical control, not necessarily involving tools. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Impact of Glaucoma and Dry Eye on Text-Based Searching.

    Science.gov (United States)

    Sun, Michelle J; Rubin, Gary S; Akpek, Esen K; Ramulu, Pradeep Y

    2017-06-01

    We determine if visual field loss from glaucoma and/or measures of dry eye severity are associated with difficulty searching, as judged by slower search times on a text-based search task. Glaucoma patients with bilateral visual field (VF) loss, patients with clinically significant dry eye, and normally-sighted controls were enrolled from the Wilmer Eye Institute clinics. Subjects searched three Yellow Pages excerpts for a specific phone number, and search time was recorded. A total of 50 glaucoma subjects, 40 dry eye subjects, and 45 controls completed study procedures. On average, glaucoma patients exhibited 57% longer search times compared to controls (95% confidence interval [CI], 26%-96%, P search times were noted among subjects with greater VF loss (P search times compared to controls, though worse Ocular Surface Disease Index (OSDI) vision-related subscores were associated with longer search times (P Search times showed no association with OSDI symptom subscores (P = 0.20) or objective measures of dry eye (P > 0.08 for Schirmer's testing without anesthesia, corneal fluorescein staining, and tear film breakup time). Text-based visual search is slower for glaucoma patients with greater levels of VF loss and dry eye patients with greater self-reported visual difficulty, and these difficulties may contribute to decreased quality of life in these groups. Visual search is impaired in glaucoma and dry eye groups compared to controls, highlighting the need for compensatory strategies and tools to assist individuals in overcoming their deficiencies.

  15. Overcoming Presbyopia by Manipulating the Eyes' Optics

    Science.gov (United States)

    Zheleznyak, Leonard A.

    Presbyopia, the age-related loss of accommodation, is a visual condition affecting all adults over the age of 45 years. In presbyopia, individuals lose the ability to focus on nearby objects, due to a lifelong growth and stiffening of the eye's crystalline lens. This leads to poor near visual performance and affects patients' quality of life. The objective of this thesis is aimed towards the correction of presbyopia and can be divided into four aims. First, we examined the characteristics and limitations of currently available strategies for the correction of presbyopia. A natural-view wavefront sensor was used to objectively measure the accommodative ability of patients implanted with an accommodative intraocular lens (IOL). Although these patients had little accommodative ability based on changes in power, pupil miosis and higher order aberrations led to an improvement in through-focus retinal image quality in some cases. To quantify the through-focus retinal image quality of accommodative and multifocal IOLs directly, an adaptive optics (AO) IOL metrology system was developed. Using this system, the impact of corneal aberrations in regard to presbyopia-correcting IOLs was assessed, providing an objective measure of through-focus retinal image quality and practical guidelines for patient selection. To improve upon existing multifocal designs, we investigated retinal image quality metrics for the prediction of through-focus visual performance. The preferred metric was based on the fidelity of an image convolved with an aberrated point spread function. Using this metric, we investigated the potential of higher order aberrations and pupil amplitude apodization to increase the depth of focus of the presbyopic eye. Thirdly, we investigated modified monovision, a novel binocular approach to presbyopia correction using a binocular AO vision simulator. In modified monovision, different magnitudes of defocus and spherical aberration are introduced to each eye, thereby

  16. Eye Movements Affect Postural Control in Young and Older Females.

    Science.gov (United States)

    Thomas, Neil M; Bampouras, Theodoros M; Donovan, Tim; Dewhurst, Susan

    2016-01-01

    Visual information is used for postural stabilization in humans. However, little is known about how eye movements prevalent in everyday life interact with the postural control system in older individuals. Therefore, the present study assessed the effects of stationary gaze fixations, smooth pursuits, and saccadic eye movements, with combinations of absent, fixed and oscillating large-field visual backgrounds to generate different forms of retinal flow, on postural control in healthy young and older females. Participants were presented with computer generated visual stimuli, whilst postural sway and gaze fixations were simultaneously assessed with a force platform and eye tracking equipment, respectively. The results showed that fixed backgrounds and stationary gaze fixations attenuated postural sway. In contrast, oscillating backgrounds and smooth pursuits increased postural sway. There were no differences regarding saccades. There were also no differences in postural sway or gaze errors between age groups in any visual condition. The stabilizing effect of the fixed visual stimuli show how retinal flow and extraocular factors guide postural adjustments. The destabilizing effect of oscillating visual backgrounds and smooth pursuits may be related to more challenging conditions for determining body shifts from retinal flow, and more complex extraocular signals, respectively. Because the older participants matched the young group's performance in all conditions, decreases of posture and gaze control during stance may not be a direct consequence of healthy aging. Further research examining extraocular and retinal mechanisms of balance control and the effects of eye movements, during locomotion, is needed to better inform fall prevention interventions.

  17. Cataract surgery in previously vitrectomized eyes.

    Science.gov (United States)

    Akinci, A; Batman, C; Zilelioglu, O

    2008-05-01

    To evaluate the results of extracapsular cataract extraction (ECCE) and phacoemulsification (PHACO) performed in previously vitrectomized eyes. In this retrospective study, 56 vitrectomized eyes that had ECCE and 60 vitrectomized eyes that had PHACO were included in the study group while 65 eyes that had PHACO in the control group. The evaluated parameters were the incidence of intra-operative and postoperative complications (IPC) and visual outcomes. Chi-squared, independent samples and paired samples tests were used for comparing the results. Deep anterior chamber (AC) was significantly more common in the PHACO group of vitrectomized eyes (PGVE) and observed in eyes that had undergone extensive vitreous removal (p ECCE group and the PGVE (p > 0.05). Some of the intra-operative conditions such as posterior synechiae, primary posterior capsular opacification (PCO) and postoperative complications such as retinal detachment (RD), PCO were significantly more common in vitrectomized eyes than the controls (p ECCE group and the PGVE (p > 0.05). Deep AC is more common in eyes with extensive vitreous removal during PHACO than ECCE. Decreasing the bottle height is advised in this case. Except for this, the results of ECCE and PHACO are similar in previously vitrectomized eyes. Posterior synechiaes, primary and postoperative PCO and RD are more common in vitrectomized eyes than the controls.

  18. Novel automatic eye detection and tracking algorithm

    Science.gov (United States)

    Ghazali, Kamarul Hawari; Jadin, Mohd Shawal; Jie, Ma; Xiao, Rui

    2015-04-01

    The eye is not only one of the most complex but also the most important sensory organ of the human body. Eye detection and eye tracking are basement and hot issue in image processing. A non-invasive eye location and eye tracking is promising for hands-off gaze-based human-computer interface, fatigue detection, instrument control by paraplegic patients and so on. For this purpose, an innovation work frame is proposed to detect and tracking eye in video sequence in this paper. The contributions of this work can be divided into two parts. The first contribution is that eye filters were trained which can detect eye location efficiently and accurately without constraints on the background and skin colour. The second contribution is that a framework of tracker based on sparse representation and LK optic tracker were built which can track eye without constraint on eye status. The experimental results demonstrate the accuracy aspects and the real-time applicability of the proposed approach.

  19. The Australian Space Eye: studying the history of galaxy formation with a CubeSat

    CERN Document Server

    Horton, Anthony; Mathers, Naomi; Pektovic, Michael; Griffin, Douglas; Barraclough, Simon; Benson, Craig; Dimitrijevic, Igor; Lambert, Andrew; Previte, Anthony; Bowen, John; Westerman, Solomon; Puig-Suari, Jordi; Reisenfeld, Sam; Lawrence, Jon; Zhelem, Ross; Colless, Matthew; Boyce, Russell

    2016-01-01

    The Australian Space Eye is a proposed astronomical telescope based on a 6U CubeSat platform. The Space Eye will exploit the low level of systematic errors achievable with a small space based telescope to enable high accuracy measurements of the optical extragalactic background light and low surface brightness emission around nearby galaxies. This project is also a demonstrator for several technologies with general applicability to astronomical observations from nanosatellites. Space Eye is based around a 90 mm aperture clear aperture all refractive telescope for broadband wide field imaging in the i and z bands.

  20. Long-term visual results in eyes cured for retinoblastoma by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Holbek, S.; Ehlers, N. (Department of Ophthalmology, Aarhus University Hospital, Aarhus (Denmark))

    1989-01-01

    Twenty-four eyes from 18 patients cured for retinoblastoma by radiation on an average 12 years previously, were re-examined with respect to visual performance. The macular functions, i.e. visual acuity, colour vision and contrast sensitivity demonstrated performances predictable from tumour localization and radiation dose to the macula. The rod functions, i.e. visual field and dark adaptation were found to be relatively resistant to the radiation treatment. A special problem encountered in two-eyed patients was the unavoidable amblyopia dut to unequal handicaps in the two eyes at the vulnerable age. (author).