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Sample records for human non-rapid eye

  1. Correlation between regular mouthing movements and heart rate patterns during non-rapid eye movement periods in normal human fetuses between 32 and 40 weeks of gestation.

    Science.gov (United States)

    Otera, Yuka; Morokuma, Seiichi; Fukushima, Kotaro; Wake, Norio; Kato, Kiyoko

    2013-06-01

    Regular mouthing movements (RMMs) are observed during fetal non-rapid eye movement (NREM) periods. To determine the correlation between RMM and fetal heart rate (FHR) patterns during NREM periods. Fetal eye and mouth movements and FHR patterns were observed and recorded. 50 normal singleton pregnancies between 32 and 40 weeks of gestation. Changes in the power spectrum ratio of 3-minute blocks of RMM clusters, FHR with RMM clusters (HR+), and FHR without RMM clusters (HR-) were calculated at a frequency band of 0.02 Hz among 3 gestational age groups: group 1, 32-34 weeks gestation; group 2, 35-37 weeks gestation; group 3, 38-40 weeks gestation. We calculated the percentage of cases showing dominant peak ratios of RMM and HR+ in the same frequency band, the maximum correlation coefficient, and its lag time. In group 3, the dominant peaks of both RM and HR+ were present at the same frequency band, 0.06-0.08 Hz; this was not seen in the other groups' relative power spectral patterns. The percentage of cases showing dominant peaks of RMM and HR+ in the same frequency band increased with advancing gestational age. The maximum correlation coefficient in groups 1 (0.28 ± 0.11) and 3 (0.45 ± 0.14) differed significantly (p<0.05). The correlation between RMM and FHR patterns became stronger, and their rhythmicity was similar, from 38 to 40 gestational weeks, suggesting that a common center starts to govern both patterns at approximately 38 weeks gestation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Effects of partial sleep deprivation on slow waves during non-rapid eye movement sleep: A high density EEG investigation.

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    Plante, David T; Goldstein, Michael R; Cook, Jesse D; Smith, Richard; Riedner, Brady A; Rumble, Meredith E; Jelenchick, Lauren; Roth, Andrea; Tononi, Giulio; Benca, Ruth M; Peterson, Michael J

    2016-02-01

    Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation. Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline. Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation. Topographic changes in slow waves occur across the course of partial sleep restriction and recovery. These results demonstrate a homeostatic response to partial sleep loss in humans. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  3. Effects of partial sleep deprivation on slow waves during non-rapid eye movement sleep: a high density EEG investigation

    Science.gov (United States)

    Plante, David T.; Goldstein, Michael R.; Cook, Jesse D.; Smith, Richard; Riedner, Brady A.; Rumble, Meredith E.; Jelenchick, Lauren; Roth, Andrea; Tononi, Giulio; Benca, Ruth M.; Peterson, Michael J.

    2015-01-01

    Objective Changes in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation. Methods Twenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline. Results Changes in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation. Conclusions Topographic changes in slow waves occur across the course of partial sleep restriction and recovery. Significance These results demonstrate a homeostatic response to partial sleep loss in humans. PMID:26596212

  4. Shorter duration of non-rapid eye movement sleep slow waves in EphA4 knockout mice.

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    Freyburger, Marlène; Poirier, Gaétan; Carrier, Julie; Mongrain, Valérie

    2017-10-01

    Slow waves occurring during non-rapid eye movement sleep have been associated with neurobehavioural performance and memory. In addition, the duration of previous wakefulness and sleep impacts characteristics of these slow waves. However, molecular mechanisms regulating the dynamics of slow-wave characteristics remain poorly understood. The EphA4 receptor regulates glutamatergic transmission and synaptic plasticity, which have both been linked to sleep slow waves. To investigate if EphA4 regulates slow-wave characteristics during non-rapid eye movement sleep, we compared individual parameters of slow waves between EphA4 knockout mice and wild-type littermates under baseline conditions and after a 6-h sleep deprivation. We observed that, compared with wild-type mice, knockout mice display a shorter duration of positive and negative phases of slow waves under baseline conditions and after sleep deprivation. However, the mutation did not change slow-wave density, amplitude and slope, and did not affect the sleep deprivation-dependent changes in slow-wave characteristics, suggesting that EphA4 is not involved in the response to elevated sleep pressure. Our present findings suggest a role for EphA4 in shaping cortical oscillations during sleep that is independent from sleep need. © 2017 European Sleep Research Society.

  5. Rapid Eye Movement and Non-Rapid Eye Movement Sleep Contributions in Memory Consolidation and Resistance to Retroactive Interference for Verbal Material

    Science.gov (United States)

    Deliens, Gaétane; Leproult, Rachel; Neu, Daniel; Peigneux, Philippe

    2013-01-01

    Study Objectives: To test the hypothesis that rapid eye movement (REM) sleep contributes to the consolidation of new memories, whereas non-rapid eye movement (NREM) sleep contributes to the prevention of retroactive interference. Design: Randomized, crossover study. Setting: Two sessions of either a morning nap or wakefulness. Participants: Twenty-five healthy young adults. Interventions: Declarative learning of word pairs followed by a nap or a wake interval, then learning of interfering word pairs and delayed recall of list A. Measurements and Results: After a restricted night (24:00-06:00), participants learned a list of word pairs (list A). They were then required to either take a nap or stay awake during 45 min, after which they learned a second list of word pairs (list B) and then had to recall list A. Fifty percent of word pairs in list B shared the first word with list A, resulting in interference. Ten subjects exhibited REM sleep whereas 13 subjects exhibited NREM stage 3 (N3) sleep. An interference effect was observed in the nap but not in the wake condition. In post-learning naps, N3 sleep was associated with a reduced interference effect, which was not the case for REM sleep. Moreover, participants exhibiting N3 sleep in the post-learning nap condition also showed a reduced interference effect in the wake condition, suggesting a higher protection ability against interference. Conclusion: Our results partly support the hypothesis that non-rapid eye movement sleep contributes in protecting novel memories against interference. However, rapid eye movement sleep-related consolidation is not evidenced. Citation: Deliens G; Leproult R; Neu D; Peigneux P. Rapid eye movement and non-rapid eye movement sleep contributions in memory consolidation and resistance to retroactive interference for verbal material. SLEEP 2013;36(12):1875-1883. PMID:24293762

  6. Alterations in regional cerebral glucose metabolism across waking and non-rapid eye movement sleep in depression.

    Science.gov (United States)

    Nofzinger, Eric A; Buysse, Daniel J; Germain, Anne; Price, Julie C; Meltzer, Carolyn C; Miewald, Jean M; Kupfer, David J

    2005-04-01

    Depression is associated with sleep disturbances, including alterations in non-rapid eye movement (NREM) sleep. Non-rapid eye movement sleep is associated with decreases in frontal, parietal, and temporal cortex metabolic activity compared with wakefulness. To show that depressed patients would have less of a decrease than controls in frontal metabolism between waking and NREM sleep and to show that during NREM sleep, they would have increased activity in structures that promote arousal. Subjects completed electroencephalographic sleep and regional cerebral glucose metabolism assessments during both waking and NREM sleep using [(18)F]fluoro-2-deoxy-D-glucose positron emission tomography. General clinical research center. The study included 29 unmedicated patients who met the Structured Clinical Interview for DSM-IV criteria for current major depression and who had a score of 15 or greater on a 17-item Hamilton Rating Scale for Depression and 28 medically healthy subjects of comparable age and sex who were free of mental disorders. Electroencephalographic sleep and regional cerebral metabolism during waking and NREM sleep. Depressed patients showed smaller decreases than healthy subjects in relative metabolism in broad regions of the frontal, parietal, and temporal cortex from waking to NREM sleep. Depressed patients showed larger decreases than healthy subjects in relative metabolism in the left amygdala, anterior cingulate cortex, cerebellum, parahippocampal cortex, fusiform gyrus, and occipital cortex. However, in post hoc analyses, depressed patients showed hypermetabolism in these areas during both waking and NREM sleep. The smaller decrease in frontal metabolism from waking to NREM sleep in depressed patients is further evidence for a dynamic sleep-wake alteration in prefrontal cortex function in depression. Hypermetabolism in a ventral emotional neural system during waking in depressed patients persists into NREM sleep.

  7. Repeated Administration of Korea Red Ginseng Extract Increases Non-Rapid Eye Movement Sleep via GABAAergic Systems.

    Science.gov (United States)

    Lee, Chung-Il; Kim, Chung-Soo; Han, Jin-Yi; Oh, Eun-Hye; Oh, Ki-Wan; Eun, Jae Soon

    2012-10-01

    The current inquiry was conducted to assess the change in sleep architecture after long periods of administration to determine whether ginseng can be used in the therapy of sleeplessness. Following post-surgical recovery, red ginseng extract (RGE, 200 mg/ kg) was orally administrated to rats for 9 d. Data were gathered on the 1st, 5th, and 9th day, and an electroencephalogram was recorded 24 h after RGE administration. Polygraphic signs of unobstructed sleep-wake activities were simultaneously recorded with sleep-wake recording electrodes from 11:00 a.m. to 5:00 p.m. for 6 h. Rodents were generally tamed to freely moving polygraphic recording conditions. Although the 1st and 5th day of RGE treatment showed no effect on power densities in non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, the 9th day of RGE administration showed augmented α-wave (8.0 to 13.0 Hz) power densities in NREM and REM sleep. RGE increased total sleep and NREM sleep. The total percentage of wakefulness was only decreased on the 9th day, and the number of sleep-wake cycles was reduced after the repeated administration of RGE. Thus, the repeated administration of RGE increased NREM sleep in rats. The α-wave activities in the cortical electroencephalograms were increased in sleep architecture by RGE. Moreover, the levels of both α- and β-subunits of the γ-aminobutyric acid (GABA)A receptor were reduced in the hypothalamus of the RGE-treated groups. The level of glutamic acid decarboxylase was over-expressed in the hypothalamus. These results demonstrate that RGE increases NREM sleep via GABAAergic systems.

  8. The Role of Non-Rapid Eye Movement Slow-Wave Activity in Prefrontal Metabolism across Young and Middle Age Adults

    OpenAIRE

    Wilckens, K.A.; Aizenstein, H J; Nofzinger, E.A.; James, J. A.; Hasler, B.P.; Rosario-Rivera, B.L.; Franzen, P; Germain, A.; Hall, M. H.; Kupfer, D.J.; Price, J C.; Siegle, G.J.; Buysse, D. J.

    2016-01-01

    Electroencephalographic slow-wave activity (0.5���4 Hz) during non rapid-eye-movement (NREM) sleep is a marker for cortical reorganization, particularly within the prefrontal cortex. Greater slow-wave activity during sleep may promote greater waking prefrontal metabolic rate, and in turn, executive function. However, this process may be affected by age. Here we examined whether greater NREM slow-wave activity was associated with higher prefrontal metabolism during wakefulness and whether this...

  9. Effects of oral temazepam on slow waves during non-rapid eye movement sleep in healthy young adults: A high-density EEG investigation.

    Science.gov (United States)

    Plante, D T; Goldstein, M R; Cook, J D; Smith, R; Riedner, B A; Rumble, M E; Jelenchick, L; Roth, A; Tononi, G; Benca, R M; Peterson, M J

    2016-03-01

    Slow waves are characteristic waveforms that occur during non-rapid eye movement (NREM) sleep that play an integral role in sleep quality and brain plasticity. Benzodiazepines are commonly used medications that alter slow waves, however, their effects may depend on the time of night and measure used to characterize slow waves. Prior investigations have utilized minimal scalp derivations to evaluate the effects of benzodiazepines on slow waves, and thus the topography of changes to slow waves induced by benzodiazepines has yet to be fully elucidated. This study used high-density electroencephalography (hdEEG) to evaluate the effects of oral temazepam on slow wave activity, incidence, and morphology during NREM sleep in 18 healthy adults relative to placebo. Temazepam was associated with significant decreases in slow wave activity and incidence, which were most prominent in the latter portions of the sleep period. However, temazepam was also associated with a decrease in the magnitude of high-amplitude slow waves and their slopes in the first NREM sleep episode, which was most prominent in frontal derivations. These findings suggest that benzodiazepines produce changes in slow waves throughout the night that vary depending on cortical topography and measures used to characterize slow waves. Further research that explores the relationships between benzodiazepine-induced changes to slow waves and the functional effects of these waveforms is indicated. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. The role of non-rapid eye movement slow-wave activity in prefrontal metabolism across young and middle-aged adults.

    Science.gov (United States)

    Wilckens, Kristine A; Aizenstein, Howard J; Nofzinger, Eric A; James, Jeffrey A; Hasler, Brant P; Rosario-Rivera, Bedda L; Franzen, Peter L; Germain, Anne; Hall, Martica H; Kupfer, David J; Price, Julie C; Siegle, Greg J; Buysse, Daniel J

    2016-06-01

    Electroencephalographic slow-wave activity (0.5-4 Hz) during non-rapid eye movement (NREM) sleep is a marker for cortical reorganization, particularly within the prefrontal cortex. Greater slow wave activity during sleep may promote greater waking prefrontal metabolic rate and, in turn, executive function. However, this process may be affected by age. Here we examined whether greater NREM slow wave activity was associated with higher prefrontal metabolism during wakefulness and whether this relationship interacted with age. Fifty-two participants aged 25-61 years were enrolled into studies that included polysomnography and a (18) [F]-fluoro-deoxy-glucose positron emission tomography scan during wakefulness. Absolute and relative measures of NREM slow wave activity were assessed. Semiquantitative and relative measures of cerebral metabolism were collected to assess whole brain and regional metabolism, focusing on two regions of interest: the dorsolateral prefrontal cortex and the orbitofrontal cortex. Greater relative slow wave activity was associated with greater dorsolateral prefrontal metabolism. Age and slow wave activity interacted significantly in predicting semiquantitative whole brain metabolism and outside regions of interest in the posterior cingulate, middle temporal gyrus and the medial frontal gyrus, such that greater slow-wave activity was associated with lower metabolism in the younger participants and greater metabolism in the older participants. These results suggest that slow-wave activity is associated with cerebral metabolism during wakefulness across the adult lifespan within regions important for executive function. © 2016 European Sleep Research Society.

  11. Promotion of non-rapid eye movement sleep and activation of reticular thalamic neurons by a novel MT2 melatonin receptor ligand.

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    Ochoa-Sanchez, Rafael; Comai, Stefano; Lacoste, Baptiste; Bambico, Francis Rodriguez; Dominguez-Lopez, Sergio; Spadoni, Gilberto; Rivara, Silvia; Bedini, Annalida; Angeloni, Debora; Fraschini, Franco; Mor, Marco; Tarzia, Giorgio; Descarries, Laurent; Gobbi, Gabriella

    2011-12-14

    Melatonin activates two brain G-protein coupled receptors, MT(1) and MT(2), whose differential roles in the sleep-wake cycle remain to be defined. The novel MT(2) receptor partial agonist, N-{2-[(3-methoxyphenyl) phenylamino] ethyl} acetamide (UCM765), is here shown to selectively promote non-rapid eye movement sleep (NREMS) in rats and mice. The enhancement of NREMS by UCM765 is nullified by the pharmacological blockade or genetic deletion of MT(2) receptors. MT(2), but not MT(1), knock-out mice show a decrease in NREMS compared to the wild strain. Immunohistochemical labeling reveals that MT(2) receptors are localized in sleep-related brain regions, and notably the reticular thalamic nucleus (Rt). Microinfusion of UCM765 in the Rt promotes NREMS, and its systemic administration induces an increase in firing and rhythmic burst activity of Rt neurons, which is blocked by the MT(2) antagonist 4-phenyl-2-propionamidotetralin. Since developing hypnotics that increase NREMS without altering sleep architecture remains a medical challenge, MT(2) receptors may represent a novel target for the treatment of sleep disorders.

  12. A Biphasic Change of Regional Blood Volume in the Frontal Cortex during Non-Rapid Eye Movement Sleep: A Near-Infrared Spectroscopy Study.

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    Zhang, Zhongxing; Khatami, Ramin

    2015-08-01

    Current knowledge on hemodynamics in sleep is limited because available techniques do not allow continuous recordings and mainly focus on cerebral blood flow while neglecting other important parameters, such as blood volume (BV) and vasomotor activity. Observational study. Continuous measures of hemodynamics over the left forehead and biceps were performed using near-infrared spectroscopy (NIRS) during nocturnal polysomnography in 16 healthy participants in sleep laboratory. Temporal dynamics and mean values of cerebral and muscular oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HHb), and BV during different sleep stages were compared. A biphasic change of cerebral BV was observed which contrasted a monotonic increase of muscular BV during non-rapid eye movement sleep. A significant decrement in cerebral HbO2 and BV accompanied by an increase of HHb was recorded at sleep onset (Phase I). Prior to slow wave sleep (SWS) HbO2 and BV turned to increase whereas HHb began to decrease in subsequent Phase II suggested increased brain perfusion during SWS. The cerebral HbO2 slope correlated to BV slope in Phase I and II, but it only correlated to HHb slope in Phase II. The occurrence time of inflection points correlated to SWS latencies. Initial decrease of brain perfusion with decreased blood volume (BV) and oxygenated hemoglobin (HbO2) together with increasing muscular BV fit thermoregulation process at sleep onset. The uncorrelated and correlated slopes of HbO2 and deoxygenated hemoglobin indicate different mechanisms underlying the biphasic hemodynamic process in light sleep and slow wave sleep (SWS). In SWS, changes in vasomotor activity (i.e., increased vasodilatation) may mediate increasing cerebral and muscular BV. © 2015 Associated Professional Sleep Societies, LLC.

  13. Comparing cortical auditory processing in children with typical and atypical benign epilepsy with centrotemporal spikes: Electrophysiologic evidence of the role of non-rapid eye movement sleep abnormalities.

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    Filippini, Melissa; Boni, Antonella; Giannotta, Melania; Pini, Antonella; Russo, Angelo; Musti, Muriel Assunta; Guerra, Angelo; Lassonde, Maryse; Gobbi, Giuseppe

    2015-05-01

    The mismatch negativity (MMN) is an objective measure of central auditory discrimination. MMN alterations have been shown in children with language and/or developmental disorders. In benign focal epilepsies, neuropsychological disorders are often reported and linked to interictal epileptic discharges (IEDs) during non-rapid eye movement (NREM) sleep. There are few studies reporting MMN in children with benign epilepsy with centrotemporal spikes (BECTS) and sleep IEDs. Moreover, no MMN recording has yet been reported in atypical BECTS children with continuous spike-and-wave during sleep (CSWS). We retrospectively compared MMN in typical and atypical BECTS children, particularly addressing the impact of NREM sleep IEDs on auditory discrimination. Moreover, we attempted a neuropsychological characterization of patients. The MMN was recorded in 9 normal controls and 23 patients (14 typical BECTS and 9 atypical BECTS) in an oddball paradigm with syllable stimuli. MMN, sleep electroencephalography (EEG) and neuropsychological evaluation were realized in the same testing session. Measurable MMN responses to speech stimuli were identified in both the control and patient groups. A significant difference between control and atypical BECTS children was found with respect to amplitude (p = 0.0061). Atypical BECTS also showed a lower MMN amplitude with respect to typical BECTS, but this difference did not reach statistical significance (p = 0.0545). Statistical comparisons between groups revealed no differences in latency. Among the neuropsychological variables, academic difficulties were significantly more prominent in the patients with atypical BECTS (p = 0.04). CSWS EEG pattern affects auditory discrimination and may have a long-lasting impact on academic skills acquisition, whereas in typical BECTS children with a lower degree of IED NREM sleep, plastic brain reorganization or the preservation of participating networks may prevent such difficulty. Early

  14. Slow oscillating transcranial direct current stimulation during non-rapid eye movement sleep improves behavioral inhibition in attention-deficit/ hyperactivity disorder

    Directory of Open Access Journals (Sweden)

    Manuel Tobias Munz

    2015-08-01

    Full Text Available Background: Behavioral inhibition, which is a later-developing executive function (EF and anatomically located in prefrontal areas, is impaired in attention-deficit and hyperactivity disorder (ADHD. While optimal EFs have been shown to depend on efficient sleep in healthy subjects, the impact of sleep problems, frequently reported in ADHD, remains elusive. Findings of macroscopic sleep changes in ADHD are inconsistent, but there is emerging evidence for distinct microscopic changes with a focus on prefrontal cortical regions and non-rapid eye movement (non-REM slow-wave sleep. Recently, slow oscillations (SO during non-REM sleep were found to be less functional and, as such, may be involved in sleep-dependent memory impairments in ADHD. Objective: By augmenting slow-wave power through bilateral, slow oscillating transcranial direct current stimulation (so-tDCS, frequency = 0.75 Hz during non-REM sleep, we aimed to improve daytime behavioral inhibition in children with ADHD. Methods: 14 boys (10-14 yrs diagnosed with ADHD were included. In a randomized, double-blind, cross-over design, patients received so-tDCS either in the first or in the second experimental sleep night. Inhibition control was assessed with a visuomotor go/no-go task. Intrinsic alertness was assessed with a simple stimulus response task. To control for visuomotor performance, motor memory was assessed with a finger sequence tapping task. Results: SO-power was enhanced during early non-REM sleep, accompanied by slowed reaction times and decreased standard deviations of reaction times, in the go/no-go task after so-tDCS. In contrast, intrinsic alertness and motor memory performance were not improved by so-tDCS. Conclusion: Since behavioral inhibition but not intrinsic alertness or motor memory was improved by so-tDCS, our results suggest that lateral prefrontal slow oscillations during sleep might play a specific role for executive functioning in ADHD.

  15. Genetics of rapid eye movement sleep in humans

    OpenAIRE

    Adamczyk, M.; Ambrosius, U; Lietzenmaier, S; Wichniak, A; Holsboer, F.; Friess, E

    2015-01-01

    The trait-like nature of electroencephalogram (EEG) is well established. Furthermore, EEG of wake and non-rapid eye movement (non-REM) sleep has been shown to be highly heritable. However, the genetic effects on REM sleep EEG microstructure are as yet unknown. REM sleep is of special interest since animal and human data suggest a connection between REM sleep abnormalities and the pathophysiology of psychiatric and neurological diseases. Here we report the results of a study in monozygotic (MZ...

  16. Normal Morning Melanin-Concentrating Hormone Levels and No Association with Rapid Eye Movement or Non-Rapid Eye Movement Sleep Parameters in Narcolepsy Type 1 and Type 2.

    Science.gov (United States)

    Schrölkamp, Maren; Jennum, Poul J; Gammeltoft, Steen; Holm, Anja; Kornum, Birgitte R; Knudsen, Stine

    2017-02-15

    Other than hypocretin-1 (HCRT-1) deficiency in narcolepsy type 1 (NT1), the neurochemical imbalance of NT1 and narcolepsy type 2 (NT2) with normal HCRT-1 levels is largely unknown. The neuropeptide melanin-concentrating hormone (MCH) is mainly secreted during sleep and is involved in rapid eye movement (REM) and non-rapid eye movement (NREM) sleep regulation. Hypocretin neurons reciprocally interact with MCH neurons. We hypothesized that altered MCH secretion contributes to the symptoms and sleep abnormalities of narcolepsy and that this is reflected in morning cerebrospinal fluid (CSF) MCH levels, in contrast to previously reported normal evening/afternoon levels. Lumbar CSF and plasma were collected from 07:00 to 10:00 from 57 patients with narcolepsy (subtypes: 47 NT1; 10 NT2) diagnosed according to International Classification of Sleep Disorders, Third Edition (ICSD-3) and 20 healthy controls. HCRT-1 and MCH levels were quantified by radioimmunoassay and correlated with clinical symptoms, polysomnography (PSG), and Multiple Sleep Latency Test (MSLT) parameters. CSF and plasma MCH levels were not significantly different between narcolepsy patients regardless of ICSD-3 subtype, HCRT-1 levels, or compared to controls. CSF MCH and HCRT-1 levels were not significantly correlated. Multivariate regression models of CSF MCH levels, age, sex, and body mass index predicting clinical, PSG, and MSLT parameters did not reveal any significant associations to CSF MCH levels. Our study shows that MCH levels in CSF collected in the morning are normal in narcolepsy and not associated with the clinical symptoms, REM sleep abnormalities, nor number of muscle movements during REM or NREM sleep of the patients. We conclude that morning lumbar CSF MCH measurement is not an informative diagnostic marker for narcolepsy.

  17. Arthropods affecting the human eye.

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    Panadero-Fontán, Rosario; Otranto, Domenico

    2015-02-28

    Ocular infestations by arthropods consist in the parasitization of the human eye, either directly (e.g., some insect larvae causing ophthalmomyiasis) or via arthropods feeding on lachrymal/conjunctival secretions (e.g., some eye-seeking insects, which also act as vectors of eye pathogens). In addition, demodicosis and phthiriasis may also cause eye discomfort in humans. Ophthalmomyiasis by larvae of the families Oestridae, Calliphoridae and Sarcophagidae, are frequent causative agents of human ocular infestations. Over the last decades, the extensive use of macrocyclic lactones in cattle has reduced the frequency of infestations by Hypoderma bovis and Hypoderma lineatum (family Oestridae), and consequently, human infestations by these species. A prompt diagnosis of ocular myiasis (e.g., by serological tests) is pivotal for positive prognoses, particularly when the larvae are not detectable during the ophthalmologic examination. Molecular diagnoses may also assist physicians and parasitologists in achieving time-efficient diagnoses of infestations by Oestridae causing myiasis. Finally, due to widespread international travel to exotic destinations, cases of myiasis are increasing in non-endemic areas, therefore requiring physicians to acquire a profound knowledge of the clinical symptoms linked to these infestations to prevent costly, inappropriate treatments or severe complications. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. A novel non-rapid-eye movement and rapid-eye-movement parasomnia with sleep breathing disorder associated with antibodies to IgLON5: a case series, characterisation of the antigen, and post-mortem study.

    Science.gov (United States)

    Sabater, Lidia; Gaig, Carles; Gelpi, Ellen; Bataller, Luis; Lewerenz, Jan; Torres-Vega, Estefanía; Contreras, Angeles; Giometto, Bruno; Compta, Yaroslau; Embid, Cristina; Vilaseca, Isabel; Iranzo, Alex; Santamaría, Joan; Dalmau, Josep; Graus, Francesc

    2014-06-01

    Autoimmunity might be associated with or implicated in sleep and neurodegenerative disorders. We aimed to describe the features of a novel neurological syndrome associated with prominent sleep dysfunction and antibodies to a neuronal antigen. In this observational study, we used clinical and video polysomnography to identify a novel sleep disorder in three patients referred to the Sleep Unit of Hospital Clinic, University of Barcelona, Spain, for abnormal sleep behaviours and obstructive sleep apnoea. These patients had antibodies against a neuronal surface antigen, which were also present in five additional patients referred to our laboratory for antibody studies. These five patients had been assessed with polysomnography, which was done in our sleep unit in one patient and the recording reviewed in a second patient. Two patients underwent post-mortem brain examination. Immunoprecipitation and mass spectrometry were used to characterise the antigen and develop an assay for antibody testing. Serum or CSF from 298 patients with neurodegenerative, sleep, or autoimmune disorders served as control samples. All eight patients (five women; median age at disease onset 59 years [range 52-76]) had abnormal sleep movements and behaviours and obstructive sleep apnoea, as confirmed by polysomnography. Six patients had chronic progression with a median duration from symptom onset to death or last visit of 5 years (range 2-12); in four the sleep disorder was the initial and most prominent feature, and in two it was preceded by gait instability followed by dysarthria, dysphagia, ataxia, or chorea. Two patients had a rapid progression with disequilibrium, dysarthria, dysphagia, and central hypoventilation, and died 2 months and 6 months, respectively, after symptom onset. In five of five patients, video polysomnography showed features of obstructive sleep apnoea, stridor, and abnormal sleep architecture (undifferentiated non-rapid-eye-movement [non-REM] sleep or poorly structured

  19. Application effect of recombinant human epidermal growth factor derivative Eye drops in treatment of dry eye

    OpenAIRE

    Paerzhati·Tuerdi; Yan-Chun Wang

    2015-01-01

    AIM: To investigate the application effect of recombinant human epidermal growth factor derivative eye drops(Jinyinshu)in treatment of dry eye.METHODS:Sixty cases(87 eyes)of dry eye patients were randomly divided into control group and observation group, 42 eyes and 45 eyes respectively. The control group received Chondroitin sulfate eye drops treatment, and the observation group were used for treatment of Jinyinshu. The changes of clinical efficacy, correlation index(symptom score, BUT, S I ...

  20. Adaptive Optics for the Human Eye

    Science.gov (United States)

    Williams, D. R.

    2000-05-01

    Adaptive optics can extend not only the resolution of ground-based telescopes, but also the human eye. Both static and dynamic aberrations in the cornea and lens of the normal eye limit its optical quality. Though it is possible to correct defocus and astigmatism with spectacle lenses, higher order aberrations remain. These aberrations blur vision and prevent us from seeing at the fundamental limits set by the retina and brain. They also limit the resolution of cameras to image the living retina, cameras that are a critical for the diagnosis and treatment of retinal disease. I will describe an adaptive optics system that measures the wave aberration of the eye in real time and compensates for it with a deformable mirror, endowing the human eye with unprecedented optical quality. This instrument provides fresh insight into the ultimate limits on human visual acuity, reveals for the first time images of the retinal cone mosaic responsible for color vision, and points the way to contact lenses and laser surgical methods that could enhance vision beyond what is currently possible today. Supported by the NSF Science and Technology Center for Adaptive Optics, the National Eye Institute, and Bausch and Lomb, Inc.

  1. Zoonotic helminths affecting the human eye

    Directory of Open Access Journals (Sweden)

    Eberhard Mark L

    2011-03-01

    Full Text Available Abstract Nowaday, zoonoses are an important cause of human parasitic diseases worldwide and a major threat to the socio-economic development, mainly in developing countries. Importantly, zoonotic helminths that affect human eyes (HIE may cause blindness with severe socio-economic consequences to human communities. These infections include nematodes, cestodes and trematodes, which may be transmitted by vectors (dirofilariasis, onchocerciasis, thelaziasis, food consumption (sparganosis, trichinellosis and those acquired indirectly from the environment (ascariasis, echinococcosis, fascioliasis. Adult and/or larval stages of HIE may localize into human ocular tissues externally (i.e., lachrymal glands, eyelids, conjunctival sacs or into the ocular globe (i.e., intravitreous retina, anterior and or posterior chamber causing symptoms due to the parasitic localization in the eyes or to the immune reaction they elicit in the host. Unfortunately, data on HIE are scant and mostly limited to case reports from different countries. The biology and epidemiology of the most frequently reported HIE are discussed as well as clinical description of the diseases, diagnostic considerations and video clips on their presentation and surgical treatment. Homines amplius oculis, quam auribus credunt Seneca Ep 6,5 Men believe their eyes more than their ears

  2. Theoretical investigation of aberrations upon ametropic human eyes

    Science.gov (United States)

    Tan, Bo; Chen, Ying-Ling; Lewis, J. W. L.; Baker, Kevin

    2003-11-01

    The human eye aberrations are important for visual acuity and ophthalmic diagnostics and surgical procedures. Reported monochromatic aberration data of the normal 20/20 human eyes are scarce. There exist even fewer reports of the relation between ametropic conditions and aberrations. We theoretically investigate the monochromatic and chromatic aberrations of human eyes for refractive errors of -10 to +10 diopters. Schematic human eye models are employed using optical design software for axial, index, and refractive types of ametropia.

  3. Scan of the back of human eye

    Science.gov (United States)

    2003-01-01

    ProVision Technologies, a NASA commercial space center at Sternis Space Center in Mississippi, has developed a new hyperspectral imaging (HSI) system that is much smaller than the original large units used aboard remote sensing aircraft and satellites. The new apparatus is about the size of a breadbox. HSI may be useful to ophthalmologists to study and diagnose eye health, both on Earth and in space, by examining the back of the eye to determine oxygen and blood flow quickly and without any invasion. ProVision's hyperspectral imaging system can scan the human eye and produce a graph showing optical density or light absorption, which can then be compared to a graph from a normal eye. Scans of the macula, optic disk or optic nerve head, and blood vessels can be used to detect anomalies and identify diseases in this delicate and important organ. ProVision has already developed a relationship with the University of Alabama at Birmingham, but is still on the lookout for a commercial partner in this application.

  4. New results in human eye laser diagnostics

    Science.gov (United States)

    Shubochkin, L. P.; Tuchin, Valery V.

    1991-05-01

    Different laser spectroscopy methods are applicable in ophthalmology for diseases diagnostics and biotissues state monitoring. Both groups of micro- and macrodiagnostics methods, especially laser Raman, resonance Raman, surface-enhanced Raman (SERS), Raman microprobe, fluorescence, Raman/fluorescence, infrared Fourier- transformation absorption method (FT-IR) and the method with the use of total reflection prism (ATR/FT-IR), FT-Raman , elastic and quasi-elastic light scattering spectroscopy have good possibilities in human and mammalia eye tissues diagnostics.''2 Microdiagnostics is realyzed with the help of all kinds of Raman, absorption and fluorescence spectroscopy and allows to study macromolecular structure and biochemical changes in eye tissues. These methods are very promising in analyzing of cataract mechanism formation, but not all of them can be used in early human cataract diagnostics, as far as they require comparatively high levels of laser radiation power. For example, modern means of Raman spectroscopy (computer controlled optical multichannel analyzer) in early cataract diagnostics need the crystalline lens has to be radiated by Ar laser with the power of 1 mW during is (Refs. 2,4). Macrodiagnostics of biotissues exploit such methods as elastic and quasi-elastic light scattering, interferometry, polarimetry and specle optics. These methods give information about form and dimensions of individual scattering particale of optically inhomogeneous media, distribution function of particales dimensions, optical constants, static characteristics of particles spatial location and presence of anisotropy. The investigations carried out for different eye. tissues demonstrate the possibility of use elastic light scattering techniques to diseases diagnostics and biotissues state monitoring in ophthalmology. Elastic scattering, interferometry and polarimetry methods require low levels of laser radiation power and comparatively simple installation for their

  5. Analysis of RPE morphometry in human eyes.

    Science.gov (United States)

    Bhatia, Shagun K; Rashid, Alia; Chrenek, Micah A; Zhang, Qing; Bruce, Beau B; Klein, Mitchel; Boatright, Jeffrey H; Jiang, Yi; Grossniklaus, Hans E; Nickerson, John M

    2016-01-01

    To describe the RPE morphometry of healthy human eyes regarding age and topographic location using modern computational methods with high accuracy and objectivity. We tested whether there were regional and age-related differences in RPE cell area and shape. Human cadaver donor eyes of varying ages were dissected, and the RPE flatmounts were immunostained for F-actin with AF635-phalloidin, nuclei stained with propidium iodide, and imaged with confocal microscopy. Image analysis was performed using ImageJ (NIH) and CellProfiler software. Quantitative parameters, including cell density, cell area, polygonality of cells, number of neighboring cells, and measures of cell shape, were obtained from these analyses to characterize individual and groups of RPE cells. Measurements were taken from selected areas spanning the length of the temporal retina through the macula and the mid-periphery to the far periphery. Nineteen eyes from 14 Caucasian donors of varying ages ranging from 29 to 80 years were used. Along a horizontal nasal to temporal meridian, there were differences in several cell shape and size characteristics. Generally, the cell area and shape was relatively constant and regular except in the far periphery. In the outer third of the retina, the cell area and shape differed from the inner two-thirds statistically significantly. In the macula and the far periphery, an overall decreasing trend in RPE cell density, percent hexagonal cells, and form factor was observed with increasing age. We also found a trend toward increasing cell area and eccentricity with age in the macula and the far periphery. When individuals were divided into two age groups, RPE morphometry between age groups were found in the mid-periphery. Human cadaver RPE cells differ mainly in area and shape in the outer one third compared to the inner two-thirds of the temporal retina. RPE cells become less dense and larger, lose their typical hexagonal shape, and become more oval with increasing age.

  6. Cyclooxygenase-2 expression in the normal human eye and its expression pattern in selected eye tumours

    DEFF Research Database (Denmark)

    Wang, Jinmei; Wu, Yazhen; Heegaard, Steffen

    2011-01-01

    Purpose: Cyclooxygenase-2 (COX-2) is an enzyme involved in neoplastic processes. The purpose of the present study is to investigate COX-2 expression in the normal human eye and the expression pattern in selected eye tumours involving COX-2 expressing cells. Methods: Immunohistochemical staining...... using antibodies against COX-2 was performed on paraffin sections of normal human eyes and selected eye tumours arising from cells expressing COX-2. Results: Cyclooxygenase-2 expression was found in various structures of the normal eye. Abundant expression was seen in the cornea, iris, ciliary body...... and retina. The COX-2 expression was less in tumours deriving from the ciliary epithelium and also in retinoblastoma. Conclusion: Cyclooxygenase-2 is constitutively expressed in normal human eyes. The expression of COX-2 is much lower in selected eye tumours involving COX-2 expressing cells....

  7. Outflow characteristics of isolated anterior segments of human eyes

    NARCIS (Netherlands)

    Dijkstra, B. G.; Ruijter, J. M.; Hoyng, P. F.

    1996-01-01

    To evaluate the relationship between intraocular pressure (IOP) and flow through the trabecular meshwork in isolated anterior segments of human eyes. Outflow facility (C) is thought to decrease proportionally with increasing IOP in human eyes in vivo and in vitro. Twenty-nine eviscerated human

  8. Virtual pharmacokinetic model of human eye.

    Science.gov (United States)

    Kotha, Sreevani; Murtomäki, Lasse

    2014-07-01

    A virtual pharmacokinetic 3D model of the human eye is built using Comsol Multiphysics® software, which is based on the Finite Element Method (FEM). The model considers drug release from a polymer patch placed on sclera. The model concentrates on the posterior part of the eye, retina being the target tissue, and comprises the choroidal blood flow, partitioning of the drug between different tissues and active transport at the retina pigment epithelium (RPE)-choroid boundary. Although most straightforward, in order to check the mass balance, no protein binding or metabolism is yet included. It appeared that the most important issue in obtaining reliable simulation results is the finite element mesh, while time stepping has hardly any significance. Simulations were extended to 100,000 s. The concentration of a drug is shown as a function of time at various points of retina, as well as its average value, varying several parameters in the model. This work demonstrates how anybody with basic knowledge of calculus is able to build physically meaningful models of quite complex biological systems. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Application effect of recombinant human epidermal growth factor derivative Eye drops in treatment of dry eye

    Directory of Open Access Journals (Sweden)

    Paerzhati·Tuerdi

    2015-01-01

    Full Text Available AIM: To investigate the application effect of recombinant human epidermal growth factor derivative eye drops(Jinyinshuin treatment of dry eye.METHODS:Sixty cases(87 eyesof dry eye patients were randomly divided into control group and observation group, 42 eyes and 45 eyes respectively. The control group received Chondroitin sulfate eye drops treatment, and the observation group were used for treatment of Jinyinshu. The changes of clinical efficacy, correlation index(symptom score, BUT, S I t, FLbefore and after treatment, quality of life after treatment and the incidence of adverse reactions were compared.RESULTS: In the control group, the total clinical effective rate was 71%, which was significantly lower than that in the observation group(91%, the difference was statistically significant(PPPPP>0.05.CONCLUSION: Jinyinshu is significantly effective in the treatment of dry eye, and its clinical efficacy is better than chondroitin sulfate.

  10. Aquaporins 6-12 in the human eye

    DEFF Research Database (Denmark)

    Tran, Thuy Linh; Bek, Toke; Holm, Lars

    2012-01-01

    was detected in the corneal epithelium, corneal endothelium, trabecular meshwork endothelium, ciliary epithelia, lens epithelium, the inner and outer limiting membrane of the retina, the retinal pigment epithelium and the capillary endothelium of all parts of the eye. AQP9 immunolabelling was detected......Purpose: Aquaporins (AQPs) are widely expressed and have diverse distribution patterns in the eye. AQPs 0-5 have been localized at the cellular level in human eyes. We investigated the presence of the more recently discovered AQPs 6-12 in the human eye. Methods: RT-PCR was performed on fresh tissue...... from two human eyes divided into the cornea, corneal limbus, ciliary body and iris, lens, choroid, optic nerve, retina and sclera. Each structure was examined to detect the mRNA of AQPs 6-12. Twenty-one human eyes were examined using immunohistochemical and immunofluorescence techniques to determine...

  11. Cyclooxygenase-2 expression in the normal human eye and its expression pattern in selected eye tumours

    DEFF Research Database (Denmark)

    Wang, Jinmei; Wu, Yazhen; Heegaard, Steffen

    2011-01-01

    and retina. The COX-2 expression was less in tumours deriving from the ciliary epithelium and also in retinoblastoma. Conclusion: Cyclooxygenase-2 is constitutively expressed in normal human eyes. The expression of COX-2 is much lower in selected eye tumours involving COX-2 expressing cells....

  12. Gamma crystallins of the human eye lens.

    Science.gov (United States)

    Vendra, Venkata Pulla Rao; Khan, Ismail; Chandani, Sushil; Muniyandi, Anbukkarasi; Balasubramanian, Dorairajan

    2016-01-01

    Protein crystallins co me in three types (α, β and γ) and are found predominantly in the eye, and particularly in the lens, where they are packed into a compact, plastic, elastic, and transparent globule of proper refractive power range that aids in focusing incoming light on to the retina. Of these, the γ-crystallins are found largely in the nuclear region of the lens at very high concentrations (>400 mg/ml). The connection between their structure and inter-molecular interactions and lens transparency is an issue of particular interest. We review the origin and phylogeny of the gamma crystallins, their special structure involving the use of Greek key supersecondary structural motif, and how they aid in offering the appropriate refractive index gradient, intermolecular short range attractive interactions (aiding in packing them into a transparent ball), the role that several of the constituent amino acid residues play in this process, the thermodynamic and kinetic stability and how even single point mutations can upset this delicate balance and lead to intermolecular aggregation, forming light-scattering particles which compromise transparency. We cite several examples of this, and illustrate this by cloning, expressing, isolating and comparing the properties of the mutant protein S39C of human γS-crystallin (associated with congenital cataract-microcornea), with those of the wild type molecule. In addition, we note that human γ-crystallins are also present in other parts of the eye (e.g., retina), where their functions are yet to be understood. There are several 'crucial' residues in and around the Greek key motifs which are essential to maintain the compact architecture of the crystallin molecules. We find that a mutation that replaces even one of these residues can lead to reduction in solubility, formation of light-scattering particles and loss of transparency in the molecular assembly. Such a molecular understanding of the process helps us construct the

  13. Eye movement-invariant representations in the human visual system.

    Science.gov (United States)

    Nishimoto, Shinji; Huth, Alexander G; Bilenko, Natalia Y; Gallant, Jack L

    2017-01-01

    During natural vision, humans make frequent eye movements but perceive a stable visual world. It is therefore likely that the human visual system contains representations of the visual world that are invariant to eye movements. Here we present an experiment designed to identify visual areas that might contain eye-movement-invariant representations. We used functional MRI to record brain activity from four human subjects who watched natural movies. In one condition subjects were required to fixate steadily, and in the other they were allowed to freely make voluntary eye movements. The movies used in each condition were identical. We reasoned that the brain activity recorded in a visual area that is invariant to eye movement should be similar under fixation and free viewing conditions. In contrast, activity in a visual area that is sensitive to eye movement should differ between fixation and free viewing. We therefore measured the similarity of brain activity across repeated presentations of the same movie within the fixation condition, and separately between the fixation and free viewing conditions. The ratio of these measures was used to determine which brain areas are most likely to contain eye movement-invariant representations. We found that voxels located in early visual areas are strongly affected by eye movements, while voxels in ventral temporal areas are only weakly affected by eye movements. These results suggest that the ventral temporal visual areas contain a stable representation of the visual world that is invariant to eye movements made during natural vision.

  14. Large-scale brain functional modularity is reflected in slow electroencephalographic rhythms across the human non-rapid eye movement sleep cycle.

    Science.gov (United States)

    Tagliazucchi, Enzo; von Wegner, Frederic; Morzelewski, Astrid; Brodbeck, Verena; Borisov, Sergey; Jahnke, Kolja; Laufs, Helmut

    2013-04-15

    Large-scale brain functional networks (measured with functional magnetic resonance imaging, fMRI) are organized into separated but interacting modules, an architecture supporting the integration of distinct dynamical processes. In this work we study how the aforementioned modular architecture changes with the progressive loss of vigilance occurring in the descent to deep sleep and we examine the relationship between the ensuing slow electroencephalographic rhythms and large-scale network modularity as measured with fMRI. Graph theoretical methods are used to analyze functional connectivity graphs obtained from fifty-five participants at wakefulness, light and deep sleep. Network modularity (a measure of functional segregation) was found to increase during deeper sleep stages but not in light sleep. By endowing functional networks with dynamical properties, we found a direct link between increased electroencephalographic (EEG) delta power (1-4 Hz) and a breakdown of inter-modular connectivity. Both EEG slowing and increased network modularity were found to quickly decrease during awakenings from deep sleep to wakefulness, in a highly coordinated fashion. Studying the modular structure itself by means of a permutation test, we revealed different module memberships when deep sleep was compared to wakefulness. Analysis of node roles in the modular structure revealed an increase in the number of locally well-connected nodes and a decrease in the number of globally well-connected hubs, which hinders interactions between separated functional modules. Our results reveal a well-defined sequence of changes in brain modular organization occurring during the descent to sleep and establish a close parallel between modularity alterations in large-scale functional networks (accessible through whole brain fMRI recordings) and the slowing of scalp oscillations (visible on EEG). The observed re-arrangement of connectivity might play an important role in the processes underlying loss of vigilance and sensory awareness during deep sleep. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Human eye and the sun hot and cold light

    CERN Document Server

    Vavilov, S I

    1965-01-01

    The Human Eye and the Sun, """"Hot"""" and """"Cold"""" Light is a translation from the Russian language and is a reproduction of texts from Volume IV of S.I. Vavilov, president of the U.S.S.R. Academy of Sciences. The book deals with theoretical and practical developments in lighting techniques. The text gives a brief introduction on the relationship of the human eye and the sun, describing the properties of light, of the sun, and of the human eye. The book describes hot (incandescence) and cold light (luminescence) as coming from different sources. These two types of light are compared. The

  16. Relating Eye Activity Measures to Human Controller Remnant Characteristics

    NARCIS (Netherlands)

    Popovici, A; Zaal, P.M.T.; Pool, D.M.; Mulder, M.; Sawaragi, T

    2016-01-01

    This study attempts to partially explain the characteristics of the human perceptual remnant, following Levison’s representation of the remnant as an equivalent observation noise. Eye activity parameters are recorded using an eye tracker in two compensatory tracking tasks in which the visual

  17. Binocular eye movements in humans: from optimal binocularity to strabismus

    NARCIS (Netherlands)

    A.F. van Leeuwen (Anna)

    2002-01-01

    textabstractBinocular vision and stereopsis is one of the major characteristics of frontal eyed species, such as humans. Binocular vision results from the projection of 3D-objects on corresponding area's of the retina's of the two eyes. An individual with. binocular vision perceives one single image

  18. Human eye colour and HERC2, OCA2 and MATP

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Børsting, Claus; Sanchez, Juan J.

    2010-01-01

    value of typing either the HERC2 SNPs rs1129038 and/or rs12913832 that are in strong linkage disequilibrium was observed when eye colour was divided into two groups, (1) blue, grey and green (light) and (2) brown and hazel (dark). Sequence variations in rs11636232 and rs7170852 in HERC2, rs1800407......Prediction of human eye colour by forensic genetic methods is of great value in certain crime investigations. Strong associations between blue/brown eye colour and the SNP loci rs1129038 and rs12913832 in the HERC2 gene were recently described. Weaker associations between eye colour and other...... in OCA2 and rs16891982 in MATP showed additional association with eye colours in addition to the effect of HERC2 rs1129038. Diplotype analysis of three sequence variations in HERC2 and one sequence variation in OCA2 showed the best discrimination between light and dark eye colours with a likelihood ratio...

  19. Simulation of wave propagation inside a human eye: acoustic eye model (AEM)

    Science.gov (United States)

    Požar, T.; Halilovič, M.; Horvat, D.; Petkovšek, R.

    2018-02-01

    The design and development of the acoustic eye model (AEM) is reported. The model consists of a computer-based simulation that describes the propagation of mechanical disturbance inside a simplified model of a human eye. The capabilities of the model are illustrated with examples, using different laser-induced initial loading conditions in different geometrical configurations typically occurring in ophthalmic medical procedures. The potential of the AEM is to predict the mechanical response of the treated eye tissue in advance, thus complementing other preliminary procedures preceding medical treatments.

  20. Human fetal eye movements: detection in utero by ultrasonography.

    Science.gov (United States)

    Bots, R S; Nijhuis, J G; Martin, C B; Prechtl, H F

    1981-02-01

    Eye movements of the human fetus were detected in utero by means of real-time B-scan and M-mode ultrasonography. In 14 low-risk fetuses studied between 32 weeks menstrual age and term either rapid or slow eye movements or a mixture of both types were detected in 60 +/- 10% (mean +/- SD) of 558 2 min scoring epochs. A comparison of direct echoscopic detection of eye movements in a 3-day-old neonate confirmed that the movements observed in the orbital region with the real-time scanner corresponded well with eye movements seen directly. Thus eye movements can be added to the list of phenomena which can be observed noninvasively for the study of human fetal behaviour.

  1. Human classifier: Observers can deduce task solely from eye movements.

    Science.gov (United States)

    Bahle, Brett; Mills, Mark; Dodd, Michael D

    2017-07-01

    Computer classifiers have been successful at classifying various tasks using eye movement statistics. However, the question of human classification of task from eye movements has rarely been studied. Across two experiments, we examined whether humans could classify task based solely on the eye movements of other individuals. In Experiment 1, human classifiers were shown one of three sets of eye movements: Fixations, which were displayed as blue circles, with larger circles meaning longer fixation durations; Scanpaths, which were displayed as yellow arrows; and Videos, in which a neon green dot moved around the screen. There was an additional Scene manipulation in which eye movement properties were displayed either on the original scene where the task (Search, Memory, or Rating) was performed or on a black background in which no scene information was available. Experiment 2 used similar methods but only displayed Fixations and Videos with the same Scene manipulation. The results of both experiments showed successful classification of Search. Interestingly, Search was best classified in the absence of the original scene, particularly in the Fixation condition. Memory also was classified above chance with the strongest classification occurring with Videos in the presence of the scene. Additional analyses on the pattern of correct responses in these two conditions demonstrated which eye movement properties successful classifiers were using. These findings demonstrate conditions under which humans can extract information from eye movement characteristics in addition to providing insight into the relative success/failure of previous computer classifiers.

  2. Indentation and needle insertion properties of the human eye

    Science.gov (United States)

    Matthews, A; Hutnik, C; Hill, K; Newson, T; Chan, T; Campbell, G

    2014-01-01

    Purpose Characterization of the biomechanical properties of the human eye has a number of potential utilities. One novel purpose is to provide the basis for development of suitable tissue-mimicking material. The purpose of this study was to determine the indentation and needle insertion characteristics on human eye globes and tissue strips. Methods An indenter assessed the elastic response of human eye globes and tissue strips under increasing compressive loads. Needle insertion determined the force (N) needed to penetrate various areas of the eye wall. Results The results demonstrated that globes underwent slightly greater indentation at the midline than at the central cornea, and corneal strips indented twofold more than scleral strips, although neither difference was significant (P=0.400 and P=0.100, respectively). Significant differences were observed among various areas of needle insertion (Peye construct with potential utility as a model for use in ophthalmology research and surgical teaching. PMID:24810571

  3. Isometric force development in human horizontal eye muscles and pulleys during saccadic eye movements.

    Science.gov (United States)

    Lennerstrand, Gunnar; Bolzani, Roberto; Benassi, Mariagrazia; Tian, Suna; Schiavi, Costantino

    2009-11-01

    The connective tissue elements forming the check ligaments and portals of the human eye muscles have recently been ascribed with a pulley function. Active positioning of the pulleys over orbital layer contraction during eye movements has been suggested. Other studies have instead demonstrated fibrous tissue connections between all parts of the muscle and the pulleys. We aimed to compare the isometric force developed at the muscle tendon and at the pulleys of the horizontal eye muscles, and to investigate which eye muscle structures might exert force on the pulleys. Isometric force development was recorded from the lateral and medial rectus muscles in six patients operated for strabismus under topical anaesthesia. Two strain gauge probes were used, each attached with 5-0 silk sutures either to the muscle tendon or to the pulley. The eye muscles were activated by horizontal saccadic eye movements in steps from 30 degrees in the off-direction to 30 degrees in the on-direction of the muscles. The forces developed at the tendon and pulley were almost identical with respect to amplitude and other parameters. No differences were found in forces developed at the pulleys of the medial and lateral rectus muscles. The results support the presence of fibrous tissue connections between all eye muscle fibres and pulley structures, rather than orbital fibre control of the pulley.

  4. Binocular eye movements in humans: from optimal binocularity to strabismus

    OpenAIRE

    Leeuwen, Anna

    2002-01-01

    textabstractBinocular vision and stereopsis is one of the major characteristics of frontal eyed species, such as humans. Binocular vision results from the projection of 3D-objects on corresponding area's of the retina's of the two eyes. An individual with. binocular vision perceives one single image of the object containing depth information (binocular vision). The minute differences between the' left and the right image (disparity) ideally give rise to stereoscopic vision. This entity of the...

  5. Optical analysis of human eye using electromagnetic wave theory.

    Science.gov (United States)

    Can, Melih G; Oner, Bilgehan B; Kurt, Hamza

    2013-10-01

    We present a two-dimensional electromagnetic analysis of light propagation through the human eye to examine the eye's optical properties. The electromagnetic approach has intriguing advantages over the conventional and frequently implemented ray optics analysis. The chromatic, spherical, and coma aberrations and the intensity of the focused light at the retina are computed in this work via full-wave analysis. We also investigate the effects of the cornea's and lens's curved structures on the focusing mechanism. The focal length and chromatic and spherical aberrations are observed to change owing to age-related refractive index variation in the lens. In addition, the effects of the lens and curvatures of the human eye on focusing are analyzed. Consequently, for both young and old human eye lenses, the differences due to the aberration variations, curvature surfaces, and gradient index are explored by the wave approach. The intensity distributions on the retina for both on- and off-axis illumination are calculated. A strong correlation between the locations of the nerve fibers and the intensity distribution is confirmed. On the basis of the findings, we can conclude that visual impairment due to deterioration of the human eye structure is more dramatic than that due to aging.

  6. Face and eye scanning in gorillas (Gorilla gorilla), orangutans (Pongo abelii), and humans (Homo sapiens): unique eye-viewing patterns in humans among hominids.

    Science.gov (United States)

    Kano, Fumihiro; Call, Josep; Tomonaga, Masaki

    2012-11-01

    Because the faces and eyes of primates convey a rich array of social information, the way in which primates view faces and eyes reflects species-specific strategies for facial communication. How are humans and closely related species such as great apes similar and different in their viewing patterns for faces and eyes? Following previous studies comparing chimpanzees (Pan troglodytes) with humans (Homo sapiens), this study used the eye-tracking method to directly compare the patterns of face and eye scanning by humans, gorillas (Gorilla gorilla), and orangutans (Pongo abelii). Human and ape participants freely viewed pictures of whole bodies and full faces of conspecifics and allospecifics under the same experimental conditions. All species were strikingly similar in that they viewed predominantly faces and eyes. No particular difference was identified between gorillas and orangutans, and they also did not differ from the chimpanzees tested in previous studies. However, humans were somewhat different from apes, especially with respect to prolonged eye viewing. We also examined how species-specific facial morphologies, such as the male flange of orangutans and the black-white contrast of human eyes, affected viewing patterns. Whereas the male flange of orangutans affected viewing patterns, the color contrast of human eyes did not. Humans showed prolonged eye viewing independently of the eye color of presented faces, indicating that this pattern is internally driven rather than stimulus dependent. Overall, the results show general similarities among the species and also identify unique eye-viewing patterns in humans.

  7. Human and rabbit eye responses to chemical insult.

    Science.gov (United States)

    Freeberg, F E; Nixon, G A; Reer, P J; Weaver, J E; Bruce, R D; Griffith, J F; Sanders, L W

    1986-11-01

    Groups of eight human volunteers and eight albino rabbits, under controlled laboratory conditions, were exposed in one eye without subsequent rinsing to the same concentrations and volumes of four prototype consumer products: fabric softener, shampoo, hand soap, and laundry detergent. Dose volume was 0.10 or 0.01 ml. The dose concentrations were selected to produce moderate effects with recovery within 24 to 48 hr. Two irritation scales were employed with both human and animal subjects: the Draize scale by a technician and a medical scale used with slit lamp examination by an ophthalmologist. Eyes were examined by both graders before and after dosing at specified intervals until recovery. Mean and maximum irritation scores are presented for each grading time, method, and exposure, as are the mean hours to recovery (clearing) for each exposure. Recovery times for human eyes were consistent with those reported previously for accidental human exposures to similar materials. Correlation coefficients for time to clear, comparing human vs rabbit for each dose volume-species combination across the four test products, were 0.72, 0.1 ml-human vs 0.01 ml-rabbit; 0.66, 0.01 ml-human vs 0.01 ml-rabbit; 0.40, 0.01 ml-human vs 0.1 ml-rabbit; 0.35, 0.1 ml-human vs 0.1 ml-rabbit. Thus, recovery time obtained under conditions of the "Low-Volume" test (0.01 ml-rabbit) better correlates with human eye recovery time (either dose volume) than does recovery time under Draize test conditions (0.10 ml-rabbit).(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Human volunteer study with PGME: Eye irritation during vapour exposure

    NARCIS (Netherlands)

    Emmen, H.H.; Muijser, H.; Arts, J.H.E.; Prinsen, M.K.

    2003-01-01

    The objective of this study was to establish the possible occurrence of eye irritation and subjective symptoms in human volunteers exposed to propylene glycol monomethyl ether (PGME) vapour at concentrations of 0, 100 and 150 ppm. Testing was conducted in 12 healthy male volunteers using a repeated

  9. Axial chromatic aberration of the human eye: frequency or wavelength?

    Science.gov (United States)

    Pease, P L; Barbeito, R

    1989-04-01

    The axial chromatic aberration of the human eye is nearly perfectly described by a linear function when expressed in terms of frequency rather than wavelength. Since linear functions are simple to work with and more readily understood, there are advantages for the expression of these data in terms of frequency.

  10. Toward a digital camera to rival the human eye

    Science.gov (United States)

    Skorka, Orit; Joseph, Dileepan

    2011-07-01

    All things considered, electronic imaging systems do not rival the human visual system despite notable progress over 40 years since the invention of the CCD. This work presents a method that allows design engineers to evaluate the performance gap between a digital camera and the human eye. The method identifies limiting factors of the electronic systems by benchmarking against the human system. It considers power consumption, visual field, spatial resolution, temporal resolution, and properties related to signal and noise power. A figure of merit is defined as the performance gap of the weakest parameter. Experimental work done with observers and cadavers is reviewed to assess the parameters of the human eye, and assessment techniques are also covered for digital cameras. The method is applied to 24 modern image sensors of various types, where an ideal lens is assumed to complete a digital camera. Results indicate that dynamic range and dark limit are the most limiting factors. The substantial functional gap, from 1.6 to 4.5 orders of magnitude, between the human eye and digital cameras may arise from architectural differences between the human retina, arranged in a multiple-layer structure, and image sensors, mostly fabricated in planar technologies. Functionality of image sensors may be significantly improved by exploiting technologies that allow vertical stacking of active tiers.

  11. Multiphoton tomography of the human eye

    Science.gov (United States)

    König, Karsten; Batista, Ana; Hager, Tobias; Seitz, Berthold

    2017-02-01

    Multiphoton tomography (MPT) is a novel label-free clinical imaging method for non-invasive tissue imaging with high spatial (300 nm) and temporal (100 ps) resolutions. In vivo optical histology can be realized due to the nonlinear excitation of endogenous fluorophores and second-harmonic generation (SHG) of collagen. Furthermore, optical metabolic imaging (OMI) is performed by two-photon autofluorescence lifetime imaging (FLIM). So far, applications of the multiphoton tomographs DermaInspect and MPTflex were limited to dermatology. Novel applications include intraoperative brain tumor imaging as well as cornea imaging. In this work we describe two-photon imaging of ex vivo human corneas unsuitable for transplantation. Furthermore, the cross-linking (CXL) process of corneal collagen based on UVA exposure and 0.1 % riboflavin was studied. The pharmacokinetics of the photosensitizer could be detected with high spatial resolution. Interestingly, an increase in the stromal autofluorescence intensity and modifications of the autofluorescence lifetimes were observed in the human corneal samples within a few days following CXL.

  12. Human eye visual hyperacuity: Controlled diffraction for image resolution improvement

    Science.gov (United States)

    Lagunas, A.; Domínguez, O.; Martinez-Conde, S.; Macknik, S. L.; Del-Río, C.

    2017-09-01

    The Human Visual System appears to be using a low number of sensors for image capturing, and furthermore, regarding the physical dimensions of cones—photoreceptors responsible for the sharp central vision—we may realize that these sensors are of a relatively small size and area. Nonetheless, the human eye is capable of resolving fine details thanks to visual hyperacuity and presents an impressive sensitivity and dynamic range when set against conventional digital cameras of similar characteristics. This article is based on the hypothesis that the human eye may be benefiting from diffraction to improve both image resolution and acquisition process. The developed method involves the introduction of a controlled diffraction pattern at an initial stage that enables the use of a limited number of sensors for capturing the image and makes possible a subsequent post-processing to improve the final image resolution.

  13. Effect of recombinant human epidermal growth factor eye drops and deproteinized calf blood extract eye drops on corneal edema after phacoemulsification

    National Research Council Canada - National Science Library

    Jia Wang

    2017-01-01

    AIM:To compare the effect of recombinant human epidermal growth factor eye drops and deproteinized calf blood extract eye drops on corneal edema after phacoemulsification. METHODS:Totally 72 cases(72 eyes...

  14. Wavefront sensorless adaptive optics ophthalmoscopy in the human eye

    Science.gov (United States)

    Hofer, Heidi; Sredar, Nripun; Queener, Hope; Li, Chaohong; Porter, Jason

    2011-01-01

    Wavefront sensor noise and fidelity place a fundamental limit on achievable image quality in current adaptive optics ophthalmoscopes. Additionally, the wavefront sensor ‘beacon’ can interfere with visual experiments. We demonstrate real-time (25 Hz), wavefront sensorless adaptive optics imaging in the living human eye with image quality rivaling that of wavefront sensor based control in the same system. A stochastic parallel gradient descent algorithm directly optimized the mean intensity in retinal image frames acquired with a confocal adaptive optics scanning laser ophthalmoscope (AOSLO). When imaging through natural, undilated pupils, both control methods resulted in comparable mean image intensities. However, when imaging through dilated pupils, image intensity was generally higher following wavefront sensor-based control. Despite the typically reduced intensity, image contrast was higher, on average, with sensorless control. Wavefront sensorless control is a viable option for imaging the living human eye and future refinements of this technique may result in even greater optical gains. PMID:21934779

  15. ESTIMATION OF MELANIN CONTENT IN IRIS OF HUMAN EYE

    Directory of Open Access Journals (Sweden)

    E. A. Genina

    2008-12-01

    Full Text Available Based on the experimental data obtained in vivo from digital analysis of color images of human irises, the mean melanin content in human eye irises has been estimated. For registration of color images the digital camera Olympus C-5060 has been used. The images have been obtained from irises of healthy volunteers as well as from irises of patients with open-angle glaucoma. The computer program has been developed for digital analysis of the images. The result has been useful for development of novel methods and optimization of already existing ones for non-invasive glaucoma diagnostics.

  16. Irreversible electroporation of human primary uveal melanoma in enucleated eyes.

    Directory of Open Access Journals (Sweden)

    Yossi Mandel

    Full Text Available Uveal melanoma (UM is the most common primary intraocular tumor in adults and is characterized by high rates of metastatic disease. Although brachytherapy is the most common globe-sparing treatment option for small- and medium-sized tumors, the treatment is associated with severe adverse reactions and does not lead to increased survival rates as compared to enucleation. The use of irreversible electroporation (IRE for tumor ablation has potential advantages in the treatment of tumors in complex organs such as the eye. Following previous theoretical work, herein we evaluate the use of IRE for uveal tumor ablation in human ex vivo eye model. Enucleated eyes of patients with uveal melanoma were treated with short electric pulses (50-100 µs, 1000-2000 V/cm using a customized electrode design. Tumor bioimpedance was measured before and after treatment and was followed by histopathological evaluation. We found that IRE caused tumor ablation characterized by cell membrane disruption while sparing the non-cellular sclera. Membrane disruption and loss of cellular capacitance were also associated with significant reduction in total tumor impedance and loss of impedance frequency dependence. The effect was more pronounced near the pulsing electrodes and was dependent on time from treatment to fixation. Future studies should further evaluate the potential of IRE as an alternative method of uveal melanoma treatment.

  17. [Influence of age on optical aberrations of the human eye].

    Science.gov (United States)

    Jahnke, M; Wirbelauer, C; Pham, D T

    2006-07-01

    Currently the influence of age on corneal and ocular aberrations is still insufficiently known. The aim of this clinical study was to compare age-related aberrations of human eyes. In a prospective study 98 eyes of 49 healthy patients ranging from 17 to 65 years of age (38.6+/-10.0 years) were consecutively examined. The best corrected visual acuity ranged from 0.8 to 1.6; 48 eyes were emmetropic (SE+/-0.5 D), 42 eyes myopic (SE +0.5 to +3.88 D). The corneal aberrations were derived from corneal topography (Keratron Scout, Optikon). The measurement of ocular aberrations was performed with a Tscherning wavefront aberrometer (ORK, Schwind). The aberrations of the Zernike coefficients and RMS values (1st to 4th order) were determined. The mean corneal and ocular Zernike coefficients of higher order were smaller than 0.2 microm. There was an evident decrease of wavefront aberrations with increasing order. Higher order corneal aberrations were larger than the corresponding ocular aberrations. With increasing age higher optical errors increased in complexity, and the correlation of corneal and ocular aberrations decreased with significant differences. Although the corneal ocular RMS value of the 3rd and 4th order correlated in the younger group (r=0.51, p=0.0001), there was no correlation in the older group (r=-0.48, p=0.832). The influence of age caused a significant increase of ocular aberrations of the 3rd and 4th order, in particular a tenfold extension of coma (C07) (p=0.002), a twofold extension of spherical aberration (C12) (p=0.0001), and an increase of the 3rd and 4th order RMS values (p=0.001). Increased age induced an increase in optical aberrations of the eye, which demonstrates the influence of the lens on ocular aberrations. The combination of corneal and ocular diagnostic methods is recommendable for a better understanding of visual performance.

  18. Neural constraints on eye motion in human eye-head saccades.

    Science.gov (United States)

    Misslisch, H; Tweed, D; Vilis, T

    1998-02-01

    We examined two ways in which the neural control system for eye-head saccades constrains the motion of the eye in the head. The first constraint involves Listing's law, which holds ocular torsion at zero during head-fixed saccades. During eye-head saccades, does this law govern the eye's motion in space or in the head? Our subjects, instructed to saccade between space-fixed targets with the head held still in different positions, systematically violated Listing's law of the eye in space in a way that approximately, but not perfectly, preserved Listing's law of the eye in head. This finding implies that the brain does not compute desired eye position based on the desired gaze direction alone but also considers head position. The second constraint we studied was saturation, the process where desired-eye-position commands in the brain are "clipped" to keep them within an effective oculomotor range (EOMR), which is smaller than the mechanical range of eye motion. We studied the adaptability of the EOMR by asking subjects to make head-only saccades. As predicted by current eye-head models, subjects failed to hold their eyes still in their orbits. Unexpectedly, though, the range of eye-in-head motion in the horizontal-vertical plane was on average 31% smaller in area than during normal eye-head saccades, suggesting that the EOMR had been reduced by effort of will. Larger reductions were possible with altered visual input: when subjects donned pinhole glasses, the EOMR immediately shrank by 80%. But even with its reduced EOMR, the eye still moved into the "blind" region beyond the pinhole aperture during eye-head saccades. Then, as the head movement brought the saccade target toward the pinhole, the eyes reversed their motion, anticipating or roughly matching the target's motion even though it was still outside the pinhole and therefore invisible. This finding shows that the backward rotation of the eye is timed by internal computations, not by vision. When subjects wore

  19. Human eyes with dilated pupils induce pupillary contagion in infants.

    Science.gov (United States)

    Fawcett, Christine; Arslan, Melda; Falck-Ytter, Terje; Roeyers, Herbert; Gredebäck, Gustaf

    2017-08-29

    Being sensitive and responsive to others' internal states is critical for social life. One reliable cue to what others might be feeling is pupil dilation because it is linked to increases in arousal. When adults view an individual with dilated pupils, their pupils dilate in response, suggesting not only sensitivity to pupil size, but a corresponding response as well. However, little is known about the origins or mechanism underlying this phenomenon of pupillary contagion. Here we show that 4- to 6-month-old infants show pupillary contagion when viewing photographs of eyes with varying pupil sizes: their pupils dilate in response to others' large, but not small or medium pupils. The results suggest that pupillary contagion is likely driven by a transfer of arousal and that it is present very early in life in human infants, supporting the view that it could be an adaptation fundamental for social and emotional development.

  20. Visual Positioning Indoors: Human Eyes vs. Smartphone Cameras.

    Science.gov (United States)

    Wu, Dewen; Chen, Ruizhi; Chen, Liang

    2017-11-16

    Artificial Intelligence (AI) technologies and their related applications are now developing at a rapid pace. Indoor positioning will be one of the core technologies that enable AI applications because people spend 80% of their time indoors. Humans can locate themselves related to a visually well-defined object, e.g., a door, based on their visual observations. Can a smartphone camera do a similar job when it points to an object? In this paper, a visual positioning solution was developed based on a single image captured from a smartphone camera pointing to a well-defined object. The smartphone camera simulates the process of human eyes for the purpose of relatively locating themselves against a well-defined object. Extensive experiments were conducted with five types of smartphones on three different indoor settings, including a meeting room, a library, and a reading room. Experimental results shown that the average positioning accuracy of the solution based on five smartphone cameras is 30.6 cm, while that for the human-observed solution with 300 samples from 10 different people is 73.1 cm.

  1. Blue eyes in lemurs and humans: same phenotype, different genetic mechanism

    DEFF Research Database (Denmark)

    Bradley, Brenda J; Pedersen, Anja; Mundy, Nicholas I

    2009-01-01

    Almost all mammals have brown or darkly-pigmented eyes (irises), but among primates, there are some prominent blue-eyed exceptions. The blue eyes of some humans and lemurs are a striking example of convergent evolution of a rare phenotype on distant branches of the primate tree. Recent work...... to and flanking the human eye-color-associated region in these lemurs, as well as other primates (human, chimpanzee, orangutan, macaque, ring-tailed lemur, mouse lemur). Aligned sequences indicated that this region is strongly conserved in both Eulemur macaco subspecies as well as the other primates (except blue...... on humans indicates that blue eye color is associated with, and likely caused by, a single nucleotide polymorphism (rs12913832) in an intron of the gene HERC2, which likely regulates expression of the neighboring pigmentation gene OCA2. This raises the immediate question of whether blue eyes in lemurs might...

  2. Human behavioral biology: commentary on Lerner and von Eye's sociobiology and human development

    NARCIS (Netherlands)

    Molenaar, P.C.M.; Burgess, R.L.

    1993-01-01

    Contends that in their examination of arguments forwarded by sociobiologists to account for key features of human development, R. M. Lerner and A. von Eye (see record 1992-23071-001) misunderstand the role of general theory in science. They also fail to characterize the work of sociobiologists

  3. Eye movement sequence generation in humans: Motor or goal updating?

    Science.gov (United States)

    Quaia, Christian; Joiner, Wilsaan M.; FitzGibbon, Edmond J.; Optican, Lance M.; Smith, Maurice A.

    2011-01-01

    Saccadic eye movements are often grouped in pre-programmed sequences. The mechanism underlying the generation of each saccade in a sequence is currently poorly understood. Broadly speaking, two alternative schemes are possible: first, after each saccade the retinotopic location of the next target could be estimated, and an appropriate saccade could be generated. We call this the goal updating hypothesis. Alternatively, multiple motor plans could be pre-computed, and they could then be updated after each movement. We call this the motor updating hypothesis. We used McLaughlin’s intra-saccadic step paradigm to artificially create a condition under which these two hypotheses make discriminable predictions. We found that in human subjects, when sequences of two saccades are planned, the motor updating hypothesis predicts the landing position of the second saccade in two-saccade sequences much better than the goal updating hypothesis. This finding suggests that the human saccadic system is capable of executing sequences of saccades to multiple targets by planning multiple motor commands, which are then updated by serial subtraction of ongoing motor output. PMID:21191134

  4. Effect of recombinant human epidermal growth factor eye drops and deproteinized calf blood extract eye drops on corneal edema after phacoemulsification

    OpenAIRE

    Jia Wang

    2017-01-01

    AIM:To compare the effect of recombinant human epidermal growth factor eye drops and deproteinized calf blood extract eye drops on corneal edema after phacoemulsification. METHODS:Totally 72 cases(72 eyes)of patients undergoing phacoemulsification were selected and divided into the observation group and the control group by random number table method. After surgery, the observation group were treated with deproteinized calf blood extract eye drops while the control group were treated with rec...

  5. Implicit prosody mining based on the human eye image capture technology

    Science.gov (United States)

    Gao, Pei-pei; Liu, Feng

    2013-08-01

    The technology of eye tracker has become the main methods of analyzing the recognition issues in human-computer interaction. Human eye image capture is the key problem of the eye tracking. Based on further research, a new human-computer interaction method introduced to enrich the form of speech synthetic. We propose a method of Implicit Prosody mining based on the human eye image capture technology to extract the parameters from the image of human eyes when reading, control and drive prosody generation in speech synthesis, and establish prosodic model with high simulation accuracy. Duration model is key issues for prosody generation. For the duration model, this paper put forward a new idea for obtaining gaze duration of eyes when reading based on the eye image capture technology, and synchronous controlling this duration and pronunciation duration in speech synthesis. The movement of human eyes during reading is a comprehensive multi-factor interactive process, such as gaze, twitching and backsight. Therefore, how to extract the appropriate information from the image of human eyes need to be considered and the gaze regularity of eyes need to be obtained as references of modeling. Based on the analysis of current three kinds of eye movement control model and the characteristics of the Implicit Prosody reading, relative independence between speech processing system of text and eye movement control system was discussed. It was proved that under the same text familiarity condition, gaze duration of eyes when reading and internal voice pronunciation duration are synchronous. The eye gaze duration model based on the Chinese language level prosodic structure was presented to change previous methods of machine learning and probability forecasting, obtain readers' real internal reading rhythm and to synthesize voice with personalized rhythm. This research will enrich human-computer interactive form, and will be practical significance and application prospect in terms of

  6. Repeatability and reliability of human eye in visual shade selection.

    Science.gov (United States)

    Özat, P B; Tuncel, İ; Eroğlu, E

    2013-12-01

    Deficiencies in the human visual percep-tion system have challenged the efficiency of the visual shade-matching protocol. The aim of this study was to evaluate the repeatability and reliability of human eye in visual shade selection. Fifty-four volunteering dentists were asked to match the shade of an upper right central incisor tooth of a single subject. The Vita 3D-Master shade guide was used for the protocol. Before each shade-matching procedure, the definitive codes of the shade tabs were hidden by an opaque strip and the shade tabs were placed into the guide randomly. The procedure was repeated 1 month later to ensure that visual memory did not affect the results. The L*, a* and b* values of the shade tabs were measured with a dental spectrophotometer (Vita Easyshade) to produce quantitative values to evaluate the protocol. The paired samples t-test and Pearson correlation test were used to compare the 1st and 2nd selections. The Yates-corrected chi-square test was use to compare qualitative values. Statistical significance was accepted at P < 0·05. Comparing baseline and 1st month records, statistical significance (P < 0·001) was found among qualitative data regarding repeatability on a yes/no (1/0) basis, revealing a very low percentage of repeatability (11·1%). Comparing baseline and 1st month records, statistical significance was not found (P = 0·000) among the L*, a*, b* and ΔE variables. These results indicate that dentists perform insufficiently regarding repeatability in visual shade matching, but they are able to select clinically acceptable shades. © 2013 John Wiley & Sons Ltd.

  7. Human secretory phospholipase A(2), group IB in normal eyes and in eye diseases

    DEFF Research Database (Denmark)

    Kolko, Miriam; Prause, Jan U; Bazan, Nicolas G

    2007-01-01

    , retinitis pigmentosa and glaucoma were evaluated. RESULTS: Expression of hGIB was found in various cells of the eye. The most abundant expression was found in retinal pigment epithelium (RPE) cells, the inner photoreceptor segments, ganglion cells and the corneal endothelium. We explored diseases involving...... a downregulation of hGIB in migrating RPE cells and in diseased corneal endothelium....

  8. Anticipatory Eye Movements in Interleaving Templates of Human Behavior

    Science.gov (United States)

    Matessa, Michael

    2004-01-01

    Performance modeling has been made easier by architectures which package psychological theory for reuse at useful levels of abstraction. CPM-GOMS uses templates of behavior to package at a task level (e.g., mouse move-click, typing) predictions of lower-level cognitive, perceptual, and motor resource use. CPM-GOMS also has a theory for interleaving resource use between templates. One example of interleaving is anticipatory eye movements. This paper describes the use of ACT-Stitch, a framework for translating CPM-GOMS templates and interleaving theory into ACT-R, to model anticipatory eye movements in skilled behavior. The anticipatory eye movements explain performance in a well-practiced perceptual/motor task, and the interleaving theory is supported with results from an eye-tracking experiment.

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

    Directory of Open Access Journals (Sweden)

    Markku Kilpeläinen

    Full Text Available 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.

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

    Science.gov (United States)

    Kilpeläinen, Markku; 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.

  11. Digital quantification of human eye color highlights genetic association of three new loci.

    NARCIS (Netherlands)

    F. Liu (Fan); A. Wollstein (Andreas); P.G. Hysi (Pirro); G.A. Ankra-Badu (Georgina); T.D. Spector (Timothy); D.J. Park (Daniel); G. Zhu; M. Larsson (Mats); D.L. Duffy (David); G.W. Montgomery (Grant); D.A. Mackey (David); S. Walsh (Susan); O. Lao Grueso (Oscar); A. Hofman (Albert); F. Rivadeneira Ramirez (Fernando); J.R. Vingerling (Hans); A.G. Uitterlinden (André); N.G. Martin (Nicholas); C.J. Hammond (Christopher); M.H. Kayser (Manfred)

    2010-01-01

    textabstractPrevious studies have successfully identified genetic variants in several genes associated with human iris (eye) color; however, they all used simplified categorical trait information. Here, we quantified continuous eye color variation into hue and saturation values using high-resolution

  12. Constructing a Computer Model of the Human Eye Based on Tissue Slice Images

    Directory of Open Access Journals (Sweden)

    Peishan Dai

    2010-01-01

    Full Text Available Computer simulation of the biomechanical and biological heat transfer in ophthalmology greatly relies on having a reliable computer model of the human eye. This paper proposes a novel method on the construction of a geometric model of the human eye based on tissue slice images. Slice images were obtained from an in vitro Chinese human eye through an embryo specimen processing methods. A level set algorithm was used to extract contour points of eye tissues while a principle component analysis was used to detect the central axis of the image. The two-dimensional contour was rotated around the central axis to obtain a three-dimensional model of the human eye. Refined geometric models of the cornea, sclera, iris, lens, vitreous, and other eye tissues were then constructed with their position and ratio relationships kept intact. A preliminary study of eye tissue deformation in eye virtual surgery was simulated by a mass-spring model based on the computer models developed.

  13. Blink effects on ongoing smooth pursuit eye movements in humans.

    Science.gov (United States)

    Rambold, Holger; El Baz, Ieman; Helmchen, Christoph

    2005-02-01

    Blinks are known to affect eye movements, e.g., saccades, slow and fast vergence, and saccade-vergence interaction, in two ways: by superimposition of blink-associated eye movements and changes of the central premotor activity in the brainstem. The goal of this study was to determine, for the first time, the effects of trigeminal evoked blinks on ongoing smooth pursuit eye movements which could be related to visual sensory or premotor neuronal changes. This was compared to the effect of a target disappearing for 100-300 ms duration during ongoing smooth pursuit (blank paradigm) in order to control for the visual sensory effects of a blink. Eye and blink movements were recorded in eight healthy subjects with the scleral search coil technique. Blink-associated eye movements during the first 50% of the blink duration were non-linearly superimposed on the smooth pursuit eye movements. Immediately after the blink-associated eye movements, the pursuit velocity slowly decreased by an average of 3.2+/-2.1 degrees /s. This decrease was not dependent on the stimulus direction. The pursuit velocity decrease caused by blinks which occluded the pupil more than 50% could be explained mostly by blanking the visual target. However, small blinks that did not occlude the pupil (smooth pursuit velocity. Thus, this blink effect on pursuit velocity cannot be explained by blink-associated eye movements or by the blink having blanked the visual input. We propose that part of this effect might either be caused by incomplete visual suppression during blinks and/or a change in the activity of omnipause neurons.

  14. High-speed adaptive optics line scan confocal retinal imaging for human eye.

    Science.gov (United States)

    Lu, Jing; Gu, Boyu; Wang, Xiaolin; Zhang, Yuhua

    2017-01-01

    Continuous and rapid eye movement causes significant intraframe distortion in adaptive optics high resolution retinal imaging. To minimize this artifact, we developed a high speed adaptive optics line scan confocal retinal imaging system. A high speed line camera was employed to acquire retinal image and custom adaptive optics was developed to compensate the wave aberration of the human eye's optics. The spatial resolution and signal to noise ratio were assessed in model eye and in living human eye. The improvement of imaging fidelity was estimated by reduction of intra-frame distortion of retinal images acquired in the living human eyes with frame rates at 30 frames/second (FPS), 100 FPS, and 200 FPS. The device produced retinal image with cellular level resolution at 200 FPS with a digitization of 512×512 pixels/frame in the living human eye. Cone photoreceptors in the central fovea and rod photoreceptors near the fovea were resolved in three human subjects in normal chorioretinal health. Compared with retinal images acquired at 30 FPS, the intra-frame distortion in images taken at 200 FPS was reduced by 50.9% to 79.7%. We demonstrated the feasibility of acquiring high resolution retinal images in the living human eye at a speed that minimizes retinal motion artifact. This device may facilitate research involving subjects with nystagmus or unsteady fixation due to central vision loss.

  15. EyeFrame: Real-time memory aid improves human multitasking via domain-general eye tracking procedures

    Directory of Open Access Journals (Sweden)

    P. eTaylor

    2015-09-01

    Full Text Available OBJECTIVE: We developed an extensively general closed-loop system to improve human interaction in various multitasking scenarios, with semi-autonomous agents, processes, and robots. BACKGROUND: Much technology is converging toward semi-independent processes with intermittent human supervision distributed over multiple computerized agents. Human operators multitask notoriously poorly, in part due to cognitive load and limited working memory. To multitask optimally, users must remember task order, e.g., the most neglected task, since longer times not monitoring an element indicates greater probability of need for user input. The secondary task of monitoring attention history over multiple spatial tasks requires similar cognitive resources as primary tasks themselves. Humans can not reliably make more than ~2 decisions/s. METHODS: Participants managed a range of 4-10 semi-autonomous agents performing rescue tasks. To optimize monitoring and controlling multiple agents, we created an automated short term memory aid, providing visual cues from users' gaze history. Cues indicated when and where to look next, and were derived from an inverse of eye fixation recency. RESULTS: Contingent eye tracking algorithms drastically improved operator performance, increasing multitasking capacity. The gaze aid reduced biases, and reduced cognitive load, measured by smaller pupil dilation. CONCLUSIONS: Our eye aid likely helped by delegating short-term memory to the computer, and by reducing decision making load. Past studies used eye position for gaze-aware control and interactive updating of displays in application-specific scenarios, but ours is the first to successfully implement domain-general algorithms. Procedures should generalize well to: process control, factory operations, robot control, surveillance, aviation, air traffic control, driving, military, mobile search and rescue, and many tasks where probability of utility is predicted by duration since last

  16. NMR Spectroscopy of Human Eye Tissues: A New Insight into Ocular Biochemistry

    Directory of Open Access Journals (Sweden)

    Tomasz Kryczka

    2014-01-01

    Full Text Available Background. The human eye is a complex organ whose anatomy and functions has been described very well to date. Unfortunately, the knowledge of the biochemistry and metabolic properties of eye tissues varies. Our objective was to reveal the biochemical differences between main tissue components of human eyes. Methods. Corneas, irises, ciliary bodies, lenses, and retinas were obtained from cadaver globes 0-1/2 hours postmortem of 6 male donors (age: 44–61 years. The metabolic profile of tissues was investigated with HR MAS 1H NMR spectroscopy. Results. A total of 29 metabolites were assigned in the NMR spectra of the eye tissues. Significant differences between tissues were revealed in contents of the most distant eye-tissues, while irises and ciliary bodies showed minimal biochemical differences. ATP, acetate, choline, glutamate, lactate, myoinositol, and taurine were identified as the primary biochemical compounds responsible for differentiation of the eye tissues. Conclusions. In this study we showed for the first time the results of the analysis of the main human eye tissues with NMR spectroscopy. The biochemical contents of the selected tissues seemed to correspond to their primary anatomical and functional attributes, the way of the delivery of the nutrients, and the location of the tissues in the eye.

  17. Objective measurement of the optical image quality in the human eye

    Science.gov (United States)

    Navarro, Rafael M.

    2001-05-01

    This communication reviews some recent studies on the optical performance of the human eye. Although the retinal image cannot be recorded directly, different objective methods have been developed, which permit to determine optical quality parameters, such as the Point Spread Function (PSF), the Modulation Transfer Function (MTF), the geometrical ray aberrations or the wavefront distortions, in the living human eye. These methods have been applied in both basic and applied research. This includes the measurement of the optical performance of the eye across visual field, the optical quality of eyes with intraocular lens implants, the aberrations induced by LASIK refractive surgery, or the manufacture of customized phase plates to compensate the wavefront aberration in the eye.

  18. Research status of the influence of the scattering for human eye's visual quality

    Directory of Open Access Journals (Sweden)

    Qiu-Yue Luo

    2017-02-01

    Full Text Available With the development of society, the new requirements for visual health are put forward. In the past, visual acuity and contrast sensitivity were used to evaluate the visual function of human eye, but it is subjective and limited, not really reflecting human eye's visual function. In order to pursue a more sensitive and accurate objective evaluation method, experts at home and abroad make some exploratory research on visual quality. The study confirmed that the scattering is an independent factor affecting the visual quality of human eye, it can make a more scientific evaluation of visual function.This article summarizes the influence of scattering for the visual quality of human eye, according to related research at home and abroad in recent years.

  19. Simple, inexpensive technique for high-quality smartphone fundus photography in human and animal eyes

    National Research Council Canada - National Science Library

    Haddock, Luis J; Kim, David Y; Mukai, Shizuo

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily...

  20. Simple, Inexpensive Technique for High-Quality Smartphone Fundus Photography in Human and Animal Eyes

    National Research Council Canada - National Science Library

    Haddock, Luis J; Kim, David Y; Mukai, Shizuo

    2013-01-01

    Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily...

  1. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models

    National Research Council Canada - National Science Library

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-01

    In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared...

  2. The Optical Design of the Human Eye: a Critical Review

    Directory of Open Access Journals (Sweden)

    Rafael Navarro

    2009-01-01

    Full Text Available Cornea, lens and eye models are analyzed and compared to experimental findings to assess properties and eventually unveil optical design principles involved in the structure and function of the optical system of the eye. Models and data often show good match but also some paradoxes. The optical design seems to correspond to a wide angle lens. Compared to conventional optical systems, the eye presents a poor optical quality on axis, but a relatively good quality off-axis, thus yielding higher homogeneity for a wide visual field. This seems the result of an intriguing combination of the symmetry design principle with a total lack of rotational symmetry, decentrations and misalignments of the optical surfaces.

  3. Measuring Human Performance in Simulated Nuclear Power Plant Control Rooms Using Eye Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Kovesdi, Casey Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rice, Brandon Charles [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bower, Gordon Ross [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spielman, Zachary Alexander [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hill, Rachael Ann [Idaho National Lab. (INL), Idaho Falls, ID (United States); LeBlanc, Katya Lee [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-11-01

    Control room modernization will be an important part of life extension for the existing light water reactor fleet. As part of modernization efforts, personnel will need to gain a full understanding of how control room technologies affect performance of human operators. Recent advances in technology enables the use of eye tracking technology to continuously measure an operator’s eye movement, which correlates with a variety of human performance constructs such as situation awareness and workload. This report describes eye tracking metrics in the context of how they will be used in nuclear power plant control room simulator studies.

  4. Dating the time of birth: A radiocarbon calibration curve for human eye-lens crystallines

    DEFF Research Database (Denmark)

    Kjeldsen, Henrik; Heinemeier, Jan; Heegaard, Steffen

    2010-01-01

    Radiocarbon bomb-pulse dating has been used to measure the formation age of human eye-lens crystallines. Lens crystallines are special proteins in the eye-lens that consist of virtually inert tissue. The experimental data show that the radiocarbon ages to a large extent reflect the time of birth......, in accordance with expectations. Moreover, it has been possible to develop an age model for the formation of the eye-lens crystallines. From this model a radiocarbon calibration curve for lens crystallines has been calculated. As a consequence, the time of birth of humans can be determined with an accuracy...

  5. Genetic analyses of the human eye colours using a novel objective method for eye colour classification

    DEFF Research Database (Denmark)

    Andersen, Jeppe D.; Johansen, Peter; Harder, Stine

    2013-01-01

    -scores of the individuals typed as HERC2 rs12913832 G (PIE = 0.99) and rs12913832 GA (PIE = −0.71) or A (PIE = −0.87) were observed. We adjusted for the effect of HERC2 rs12913832 and showed that the quantitative PIE-scores were significantly associated with SNPs with minor effects (OCA2 rs1800407, SLC24A4 rs12896399...... by different studies and to perform large meta-studies that may reveal loci with small effects on the eye colour....

  6. Integrating the Advanced Human Eye Model (AHEM) and optical instrument models to model complete visual optical systems inclusive of the typical or atypical eye

    Science.gov (United States)

    Donnelly, William J., III

    2012-06-01

    PURPOSE: To present a commercially available optical modeling software tool to assist the development of optical instrumentation and systems that utilize and/or integrate with the human eye. METHODS: A commercially available flexible eye modeling system is presented, the Advanced Human Eye Model (AHEM). AHEM is a module that the engineer can use to perform rapid development and test scenarios on systems that integrate with the eye. Methods include merging modeled systems initially developed outside of AHEM and performing a series of wizard-type operations that relieve the user from requiring an optometric or ophthalmic background to produce a complete eye inclusive system. Scenarios consist of retinal imaging of targets and sources through integrated systems. Uses include, but are not limited to, optimization, telescopes, microscopes, spectacles, contact and intraocular lenses, ocular aberrations, cataract simulation and scattering, and twin eye model (binocular) systems. RESULTS: Metrics, graphical data, and exportable CAD geometry are generated from the various modeling scenarios.

  7. Image system analysis of human eye wave-front aberration on the basis of HSS

    Science.gov (United States)

    Xu, Ancheng

    2017-07-01

    Hartmann-Shack sensor (HSS) has been used in objective measurement of human eye wave-front aberration, but the research on the effects of sampling point size on the accuracy of the result has not been reported. In this paper, point spread function (PSF) of the whole system mathematical model was obtained via measuring the optical imaging system structure of human eye wave-front aberration measurement. The impact of Airy spot size on the accuracy of system was analyzed. Statistics study show that the geometry of Airy spot size of the ideal light source sent from eye retina formed on the surface of HSS is far smaller than the size of the HSS sample point image used in the experiment. Therefore, the effect of Airy spot on the precision of the system can be ignored. This study theoretically and experimentally justifies the reliability and accuracy of human eye wave-front aberration measurement based on HSS.

  8. Optics of the human cornea influence the accuracy of stereo eye-tracking methods: a simulation study

    National Research Council Canada - National Science Library

    Barsingerhorn, A.D; Boonstra, F.N; Goossens, H.H.L.M

    2017-01-01

    .... However, the human cornea is slightly aspheric and has two refractive surfaces. Here we used ray-tracing and the Navarro eye-model to study how these optical properties affect the accuracy of different stereo eye-tracking methods...

  9. Basement membrane abnormalities in human eyes with diabetic retinopathy

    DEFF Research Database (Denmark)

    Ljubimov, A V; Burgeson, R E; Butkowski, R J

    1996-01-01

    Vascular and parenchymal basement membranes (BMs) are thickened in diabetes, but alterations in individual BM components in diabetic eyes, especially in diabetic retinopathy (DR), are obscure. To identify abnormalities in the distribution of specific constituents, we analyzed cryostat sections...... VI, VIII, XII, and XIV collagen were newly identified. Diabetic BM thickening appears to involve qualitative alterations of specific BM markers at an advanced disease stage, with the appearance of DR....

  10. The Human Eye Position Control System in a Rehabilitation Setting

    Directory of Open Access Journals (Sweden)

    Yvonne Nolan

    2005-01-01

    Full Text Available Our work at Ireland’s National Rehabilitation Hospital involves designing communication systems for people suffering from profound physical disabilities. One such system uses the electro-oculogram, which is an (x,y system of voltages picked up by pairs of electrodes placed, respectively, above and below and on either side of the eyes. The eyeball has a dc polarisation between cornea and back, arising from the photoreceptor rods and cones in the retina. As the eye rotates, the varying voltages projected onto the electrodes drive a cursor over a mimic keyboard on a computer screen. Symbols are selected with a switching action derived, for example, from a blink. Experience in using this mode of communication has given us limited facilities to study the eye position control system. We present here a resulting new feedback model for rotation in either the vertical or the horizontal plane, which involves the eyeball controlled by an agonist-antagonist muscle pair, modelled by a single equivalent bidirectional muscle with torque falling off linearly with angular velocity. We have incorporated muscle spindles and have tuned them by pole assignment associated with an optimum stability criterion.

  11. The expression of Mas-receptor of the renin-angiotensin system in the human eye.

    Science.gov (United States)

    Vaajanen, A; Kalesnykas, G; Vapaatalo, H; Uusitalo, H

    2015-07-01

    The local renin-angiotensin system has been held to be expressed in many organs, including the eye. It has an important role in the regulation of local fluid homeostasis, cell proliferation, fibrosis, and vascular tone. Mas-receptor (Mas-R) is a potential receptor acting mainly opposite to the well-known angiotensin II receptor type 1. The aim of this study was to determine if Mas-R is expressed in the human eye. Seven enucleated human eyes were used in immunohistochemical detection of Mas-R and its endogenous ligand angiotensin (1-7) [Ang(1-7)]. Both light microscopy and immunofluorescent detection methods were used. A human kidney preparation sample was used as control. The Mas-R was found to have nuclear localization, and localized in the retinal nuclear layers and in the structures of the anterior segment of the eye. A cytoplasmic immunostaining pattern of Ang(1-7) was found in the inner and outer nuclear and plexiform layers of the retina and in the ciliary body. To the best of our knowledge, this is the first report showing Mas-R expression in the human eye. Its localization suggests that it may have a role in physiological and pathological processes in the anterior part of the eye and in the retina.

  12. Human Commercial Models' Eye Colour Shows Negative Frequency-Dependent Selection.

    Science.gov (United States)

    Forti, Isabela Rodrigues Nogueira; Young, Robert John

    2016-01-01

    In this study we investigated the eye colour of human commercial models registered in the UK (400 female and 400 male) and Brazil (400 female and 400 male) to test the hypothesis that model eye colour frequency was the result of negative frequency-dependent selection. The eye colours of the models were classified as: blue, brown or intermediate. Chi-square analyses of data for countries separated by sex showed that in the United Kingdom brown eyes and intermediate colours were significantly more frequent than expected in comparison to the general United Kingdom population (PBrazilian population. These results support the hypothesis that model eye colour is the result of negative frequency-dependent selection. This could be the result of people using eye colour as a marker of genetic diversity and finding rarer eye colours more attractive because of the potential advantage more genetically diverse offspring that could result from such a choice. Eye colour may be important because in comparison to many other physical traits (e.g., hair colour) it is hard to modify, hide or disguise, and it is highly polymorphic.

  13. The Transverse Chromatic Aberration of the Human Eye.

    Science.gov (United States)

    Simonet, Pierre

    1990-01-01

    In this study, the horizontal components of optical and perceived transverse chromatic aberration (T.C.A.) at the fovea are measured between 486 and 656 nm using a vernier task at 30 and 1000 lux. The relationship between chromostereopsis and T.C.A. is analysed at these two levels of illuminance. During these experiments, a new video frame grabbing technique with a computer generated overlay is used to monitor the pupil size and pupil centration or to visualize the position of the image of a point source, producing a Maxwellian view, in the natural entrance pupil. Optical T.C.A. can be measured either directly in a semi-Maxwellian view when longitudinal chromatic aberration is compensated for, or indirectly in dual Maxwellian view by a chromatic parallax method. Optical T.C.A. measured in dual Maxwellian view and perceived T.C.A. assessed in normal view with a natural pupil were evaluated in a sample of 13 eyes at 30 lux and of 11 eyes at 1000 lux. The sample mean of each type of T.C.A. is in the same direction but substantially less than the predictions of schematic eye models. Perceived T.C.A. shows a greater variability among eyes than optical T.C.A. For some subjects, it appears that optical and perceived T.C.A. differ substantially at both levels of illuminance. This indicates that the effective centre of the pupil differs from the geometric centre as a consequence of the involvement of the Stiles -Crawford effect or coma in the perception of T.C.A. with natural pupils. For some subjects, perceived T.C.A. may adversely affect the optical quality of the eye. In a sample of 30 emmetropic subjects at 10 and 1000 lux, in most cases, there is an absence of perceived T.C.A. although chromostereopsis is reported. In a subset of 9 emmetropic subjects, measured chromostereopsis does not differ significantly at 1000 lux from predicted chromostereopsis, computed as the average of the monocular perceived T.C.A.s. At 30 lux, the expected relationship between

  14. Early visual evoked potentials are modulated by eye position in humans induced by whole body rotations

    Directory of Open Access Journals (Sweden)

    Petit Laurent

    2004-09-01

    Full Text Available Abstract Background To reach and grasp an object in space on the basis of its image cast on the retina requires different coordinate transformations that take into account gaze and limb positioning. Eye position in the orbit influences the image's conversion from retinotopic (eye-centered coordinates to an egocentric frame necessary for guiding action. Neuroimaging studies have revealed eye position-dependent activity in extrastriate visual, parietal and frontal areas that is along the visuo-motor pathway. At the earliest vision stage, the role of the primary visual area (V1 in this process remains unclear. We used an experimental design based on pattern-onset visual evoked potentials (VEP recordings to study the effect of eye position on V1 activity in humans. Results We showed that the amplitude of the initial C1 component of VEP, acknowledged to originate in V1, was modulated by the eye position. We also established that putative spontaneous small saccades related to eccentric fixation, as well as retinal disparity cannot explain the effects of changing C1 amplitude of VEP in the present study. Conclusions The present modulation of the early component of VEP suggests an eye position-dependent activity of the human primary visual area. Our findings also evidence that cortical processes combine information about the position of the stimulus on the retinae with information about the location of the eyes in their orbit as early as the stage of primary visual area.

  15. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models

    OpenAIRE

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-01

    Background In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. Methods A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3?mm of pupil diameter and...

  16. Eye tracking using artificial neural networks for human computer interaction.

    Science.gov (United States)

    Demjén, E; Aboši, V; Tomori, Z

    2011-01-01

    This paper describes an ongoing project that has the aim to develop a low cost application to replace a computer mouse for people with physical impairment. The application is based on an eye tracking algorithm and assumes that the camera and the head position are fixed. Color tracking and template matching methods are used for pupil detection. Calibration is provided by neural networks as well as by parametric interpolation methods. Neural networks use back-propagation for learning and bipolar sigmoid function is chosen as the activation function. The user's eye is scanned with a simple web camera with backlight compensation which is attached to a head fixation device. Neural networks significantly outperform parametric interpolation techniques: 1) the calibration procedure is faster as they require less calibration marks and 2) cursor control is more precise. The system in its current stage of development is able to distinguish regions at least on the level of desktop icons. The main limitation of the proposed method is the lack of head-pose invariance and its relative sensitivity to illumination (especially to incidental pupil reflections).

  17. Longitudinal evaluation of selected human laser eye accident cases

    Science.gov (United States)

    Zwick, Harry; Stuck, Bruce E.; Scales, David K.; Brown, Jeremiah; Ness, James W.

    1999-06-01

    Two Q-switched military accident cases involving foveal retinal damage were followed for at least two years with a variety of morphological and functional diagnostic techniques. Both cases demonstrated remarkable recovery of visual acuity and contrast sensitivity within 1 to 4 months post exposure. Early deficits in visual acuity, sine wave contrast sensitivity, various measures of color vision, and focal electrophysiological measures all showed remarkable recovery. With the use of a scanning laser ophthalmoscope (SLO), we were able to further evaluate the retinal preference threshold contrast targets and found that small targets requiring foveal resolution were initially placed superior and slightly temporal to the damaged fovea in these eyes, even though visual acuity in these eyes was 20/15 or better. In one of these cases, a return to foveal functionality was demonstrated even though the fovea appeared lightly scarred small test targets were placed at its center for detection. In the second case, the PRL stayed superior temporal. Attempts to force target resolution in this area were unsuccessful. These findings suggest a more active role of neural retinal plasticity in the damage recovery process as well as caution in assuming that all such injuries will exhibit such plasticity.

  18. Human eye analytical and mesh-geometry models for ophthalmic dosimetry using MCNP6

    Energy Technology Data Exchange (ETDEWEB)

    Angelocci, Lucas V.; Fonseca, Gabriel P.; Yoriyaz, Helio, E-mail: hyoriyaz@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Eye tumors can be treated with brachytherapy using Co-60 plaques, I-125 seeds, among others materials. The human eye has regions particularly vulnerable to ionizing radiation (e.g. crystalline) and dosimetry for this region must be taken carefully. A mathematical model was proposed in the past [1] for the eye anatomy to be used in Monte Carlo simulations to account for dose distribution in ophthalmic brachytherapy. The model includes the description for internal structures of the eye that were not treated in previous works. The aim of this present work was to develop a new eye model based on the Mesh geometries of the MCNP6 code. The methodology utilized the ABAQUS/CAE (Simulia 3DS) software to build the Mesh geometry. For this work, an ophthalmic applicator containing up to 24 model Amersham 6711 I-125 seeds (Oncoseed) was used, positioned in contact with a generic tumor defined analytically inside the eye. The absorbed dose in eye structures like cornea, sclera, choroid, retina, vitreous body, lens, optical nerve and optical nerve wall were calculated using both models: analytical and MESH. (author)

  19. A Proactive Approach of Robotic Framework for Making Eye Contact with Humans

    Directory of Open Access Journals (Sweden)

    Mohammed Moshiul Hoque

    2014-01-01

    Full Text Available Making eye contact is a most important prerequisite function of humans to initiate a conversation with others. However, it is not an easy task for a robot to make eye contact with a human if they are not facing each other initially or the human is intensely engaged his/her task. If the robot would like to start communication with a particular person, it should turn its gaze to that person and make eye contact with him/her. However, such a turning action alone is not enough to set up an eye contact phenomenon in all cases. Therefore, the robot should perform some stronger actions in some situations so that it can attract the target person before meeting his/her gaze. In this paper, we proposed a conceptual model of eye contact for social robots consisting of two phases: capturing attention and ensuring the attention capture. Evaluation experiments with human participants reveal the effectiveness of the proposed model in four viewing situations, namely, central field of view, near peripheral field of view, far peripheral field of view, and out of field of view.

  20. Goat′s eye integrated with a human cataractous lens: A training model for phacoemulsification

    Directory of Open Access Journals (Sweden)

    Sabyasachi Sengupta

    2015-01-01

    Full Text Available A relatively simple and inexpensive technique to train surgeons in phacoemulsification using a goat′s eye integrated with a human cataractous nucleus is described. The goat′s eye is placed on a bed of cotton within the lumen of a cylindrical container. This is then mounted on a rectangular thermocol so that the limbus is presented at the surgical field. After making a clear corneal entry with a keratome, the trainer makes a 5-5.5 mm continuous curvilinear capsulorhexis in the anterior lens capsule, creates a crater of adequate depth in the cortex and inserts the human nucleus within this crater in the goat′s capsular bag. The surgical wound is sutured, and the goat′s eye is ready for training. Creating the capsulorhexis with precision and making the crater of adequate depth to snugly accommodate the human nucleus are the most important steps to prevent excessive wobbling of the nucleus while training.

  1. Novel quantitative pigmentation phenotyping enhances genetic association, epistasis, and prediction of human eye colour

    Science.gov (United States)

    Wollstein, Andreas; Walsh, Susan; Liu, Fan; Chakravarthy, Usha; Rahu, Mati; Seland, Johan H.; Soubrane, Gisèle; Tomazzoli, Laura; Topouzis, Fotis; Vingerling, Johannes R.; Vioque, Jesus; Böhringer, Stefan; Fletcher, Astrid E.; Kayser, Manfred

    2017-01-01

    Success of genetic association and the prediction of phenotypic traits from DNA are known to depend on the accuracy of phenotype characterization, amongst other parameters. To overcome limitations in the characterization of human iris pigmentation, we introduce a fully automated approach that specifies the areal proportions proposed to represent differing pigmentation types, such as pheomelanin, eumelanin, and non-pigmented areas within the iris. We demonstrate the utility of this approach using high-resolution digital eye imagery and genotype data from 12 selected SNPs from over 3000 European samples of seven populations that are part of the EUREYE study. In comparison to previous quantification approaches, (1) we achieved an overall improvement in eye colour phenotyping, which provides a better separation of manually defined eye colour categories. (2) Single nucleotide polymorphisms (SNPs) known to be involved in human eye colour variation showed stronger associations with our approach. (3) We found new and confirmed previously noted SNP-SNP interactions. (4) We increased SNP-based prediction accuracy of quantitative eye colour. Our findings exemplify that precise quantification using the perceived biological basis of pigmentation leads to enhanced genetic association and prediction of eye colour. We expect our approach to deliver new pigmentation genes when applied to genome-wide association testing. PMID:28240252

  2. Geometrical theory to predict eccentric photorefraction intensity profiles in the human eye

    Science.gov (United States)

    Roorda, Austin; Campbell, Melanie C. W.; Bobier, W. R.

    1995-08-01

    In eccentric photorefraction, light returning from the retina of the eye is photographed by a camera focused on the eye's pupil. We use a geometrical model of eccentric photorefraction to generate intensity profiles across the pupil image. The intensity profiles for three different monochromatic aberration functions induced in a single eye are predicted and show good agreement with the measured eccentric photorefraction intensity profiles. A directional reflection from the retina is incorporated into the calculation. Intensity profiles for symmetric and asymmetric aberrations are generated and measured. The latter profile shows a dependency on the source position and the meridian. The magnitude of the effect of thresholding on measured pattern extents is predicted. Monochromatic aberrations in human eyes will cause deviations in the eccentric photorefraction measurements from traditional crescents caused by defocus and may cause misdiagnoses of ametropia or anisometropia. Our results suggest that measuring refraction along the vertical meridian is preferred for screening studies with the eccentric photorefractor.

  3. Category Processing and the human likeness dimension of the Uncanny Valley Hypothesis: Eye-Tracking Data.

    Science.gov (United States)

    Cheetham, Marcus; Pavlovic, Ivana; Jordan, Nicola; Suter, Pascal; Jancke, Lutz

    2013-01-01

    The Uncanny Valley Hypothesis (Mori, 1970) predicts that perceptual difficulty distinguishing between a humanlike object (e.g., lifelike prosthetic hand, mannequin) and its human counterpart evokes negative affect. Research has focused on affect, with inconsistent results, but little is known about how objects along the hypothesis' dimension of human likeness (DHL) are actually perceived. This study used morph continua based on human and highly realistic computer-generated (avatar) faces to represent the DHL. Total number and dwell time of fixations to facial features were recorded while participants (N = 60) judged avatar versus human category membership of the faces in a forced choice categorization task. Fixation and dwell data confirmed the face feature hierarchy (eyes, nose, and mouth in this order of importance) across the DHL. There were no further findings for fixation. A change in the relative importance of these features was found for dwell time, with greater preferential processing of eyes and mouth of categorically ambiguous faces compared with unambiguous avatar faces. There were no significant differences between ambiguous and human faces. These findings applied for men and women, though women generally dwelled more on the eyes to the disadvantage of the nose. The mouth was unaffected by gender. In summary, the relative importance of facial features changed on the DHL's non-human side as a function of categorization ambiguity. This change was indicated by dwell time only, suggesting greater depth of perceptual processing of the eyes and mouth of ambiguous faces compared with these features in unambiguous avatar faces.

  4. Towards Quantum Experiments with Human Eye Detectors Based on Cloning via Stimulated Emission ?

    Science.gov (United States)

    De Martini, Francesco

    2010-05-01

    In a recent theoretical paper published in Physical Review Letters, Sekatsky, Brunner, Branciard, Gisin, Simon report an extended investigation on some properties of the human eye that affect its behavior as a quantum detector. We believe that the content of this work, albeit appealing at fist sight, is highly questionable simply because the human eye cannot be adopted as a sensing device within any quantum measurement apparatus. Furthermore, the criticism raised by these Authors against a real experiment on Micro—Macro entanglement recently published in Physical Review Letters (100, 253601, 2008) is found misleading and misses its target.

  5. High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography

    Science.gov (United States)

    Sprecher, Kate E.; Riedner, Brady A.; Smith, Richard F.; Tononi, Giulio; Davidson, Richard J.; Benca, Ruth M.

    2016-01-01

    Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel) electroencephalography (EEG) during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18–65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson’s coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor. PMID:26901503

  6. Correlating Interictal Spikes with Sigma and Delta Dynamics during Non-Rapid-Eye-Movement-Sleep

    Science.gov (United States)

    Zubler, Frédéric; Rubino, Annalisa; Lo Russo, Giorgio; Schindler, Kaspar; Nobili, Lino

    2017-01-01

    Interictal spikes (IS) are one of the major hallmarks of epilepsy. Understanding the factors promoting or suppressing IS would increase our comprehension of epilepsy and possibly open new avenues for therapy. Sleep strongly influences epileptic activity, and the modulatory effects of the different sleep stages on IS have been studied for decades. However, several aspects are still disputed, in particular the role of sleep spindles and slow waves in the activation of IS during Non-REM sleep. Here, we correlate the rate of IS with quantitative measures derived from stereo-EEG during one Non-REM cycle in 10 patients suffering from drug-resistant epilepsy due to type 2 focal cortical dysplasia. We show that the IS rate (ISR) is positively correlated with sigma power (a surrogate for sleep-spindle density) but negatively correlated with delta power (surrogate for slow wave activity). In addition, we present two new indices for quantifying the spatial and temporal instability of sleep. We found that both instability indices are correlated with a high ISR. The main contribution of this study is to confirm the suppressive effect of stable deep sleep on IS. This result might influence future guidelines for therapy of patients suffering from epilepsy and sleep disorders. PMID:28690583

  7. Correlating Interictal Spikes with Sigma and Delta Dynamics during Non-Rapid-Eye-Movement-Sleep.

    Science.gov (United States)

    Zubler, Frédéric; Rubino, Annalisa; Lo Russo, Giorgio; Schindler, Kaspar; Nobili, Lino

    2017-01-01

    Interictal spikes (IS) are one of the major hallmarks of epilepsy. Understanding the factors promoting or suppressing IS would increase our comprehension of epilepsy and possibly open new avenues for therapy. Sleep strongly influences epileptic activity, and the modulatory effects of the different sleep stages on IS have been studied for decades. However, several aspects are still disputed, in particular the role of sleep spindles and slow waves in the activation of IS during Non-REM sleep. Here, we correlate the rate of IS with quantitative measures derived from stereo-EEG during one Non-REM cycle in 10 patients suffering from drug-resistant epilepsy due to type 2 focal cortical dysplasia. We show that the IS rate (ISR) is positively correlated with sigma power (a surrogate for sleep-spindle density) but negatively correlated with delta power (surrogate for slow wave activity). In addition, we present two new indices for quantifying the spatial and temporal instability of sleep. We found that both instability indices are correlated with a high ISR. The main contribution of this study is to confirm the suppressive effect of stable deep sleep on IS. This result might influence future guidelines for therapy of patients suffering from epilepsy and sleep disorders.

  8. High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography.

    Science.gov (United States)

    Sprecher, Kate E; Riedner, Brady A; Smith, Richard F; Tononi, Giulio; Davidson, Richard J; Benca, Ruth M

    2016-01-01

    Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel) electroencephalography (EEG) during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18-65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson's coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor.

  9. High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography.

    Directory of Open Access Journals (Sweden)

    Kate E Sprecher

    Full Text Available Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel electroencephalography (EEG during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18-65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson's coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor.

  10. APPLICATION OF EYE TRACKING FOR MEASUREMENT AND EVALUATION IN HUMAN FACTORS STUDIES IN CONTROL ROOM MODERNIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Kovesdi, C.; Spielman, Z.; LeBlanc, K.; Rice, B.

    2017-05-01

    An important element of human factors engineering (HFE) pertains to measurement and evaluation (M&E). The role of HFE-M&E should be integrated throughout the entire control room modernization (CRM) process and be used for human-system performance evaluation and diagnostic purposes with resolving potential human engineering deficiencies (HEDs) and other human machine interface (HMI) design issues. NUREG-0711 describes how HFE in CRM should employ a hierarchical set of measures, particularly during integrated system validation (ISV), including plant performance, personnel task performance, situation awareness, cognitive workload, and anthropometric/ physiological factors. Historically, subjective measures have been primarily used since they are easier to collect and do not require specialized equipment. However, there are pitfalls with relying solely on subjective measures in M&E such that negatively impact reliability, sensitivity, and objectivity. As part of comprehensively capturing a diverse set of measures that strengthen findings and inferences made of the benefits from emerging technologies like advanced displays, this paper discusses the value of using eye tracking as an objective method that can be used in M&E. A brief description of eye tracking technology and relevant eye tracking measures is provided. Additionally, technical considerations and the unique challenges with using eye tracking in full-scaled simulations are addressed. Finally, this paper shares preliminary findings regarding the use of a wearable eye tracking system in a full-scale simulator study. These findings should help guide future full-scale simulator studies using eye tracking as a methodology to evaluate human-system performance.

  11. Collagens and collagen-related matrix components in the human and mouse eye.

    Science.gov (United States)

    Ihanamäki, Tapio; Pelliniemi, Lauri J; Vuorio, Eero

    2004-07-01

    The three-dimensional structure of the eye plays an important role in providing a correct optical environment for vision. Much of this function is dependent on the unique structural features of ocular connective tissue, especially of the collagen types and their supramolecular structures. For example, the organization of collagen fibrils is largely responsible for transparency and refraction of cornea, lens and vitreous body, and collagens present in the sclera are largely responsible for the structural strength of the eye. Phylogenetically, most of the collagens are highly conserved between different species, which suggests that collagens also share similar functions in mice and men. Despite considerable differences between the mouse and the human eye, particularly in the proportion of the different tissue components, the difficulty of performing systematic histologic and molecular studies on the human eye has made mouse an appealing alternative to studies addressing the role of individual genes and their mutations in ocular diseases. From a genetic standpoint, the mouse has major advantages over other experimental animals as its genome is better known than that of other species and it can be manipulated by the modern techniques of genetic engineering. Furthermore, it is easy, quick and relatively cheap to produce large quantities of mice for systematic studies. Thus, transgenic techniques have made it possible to study consequences of specific mutations in genes coding for structural components of ocular connective tissues in mice. As these changes in mice have been shown to resemble those in human diseases, mouse models are likely to provide efficient tools for pathogenetic studies on human disorders affecting the extracellular matrix. This review is aimed to clarify the role of collagenous components in the mouse and human eye with a closer look at the new findings of the collagens in the cartilage and the eye, the so-called "cartilage collagens".

  12. See You See Me: the Role of Eye Contact in Multimodal Human-Robot Interaction

    Science.gov (United States)

    XU, TIAN (LINGER); ZHANG, HUI; YU, CHEN

    2016-01-01

    We focus on a fundamental looking behavior in human-robot interactions – gazing at each other’s face. Eye contact and mutual gaze between two social partners are critical in smooth human-human interactions. Therefore, investigating at what moments and in what ways a robot should look at a human user’s face as a response to the human’s gaze behavior is an important topic. Toward this goal, we developed a gaze-contingent human-robot interaction system, which relied on momentary gaze behaviors from a human user to control an interacting robot in real time. Using this system, we conducted an experiment in which human participants interacted with the robot in a joint attention task. In the experiment, we systematically manipulated the robot’s gaze toward the human partner’s face in real time and then analyzed the human’s gaze behavior as a response to the robot’s gaze behavior. We found that more face looks from the robot led to more look-backs (to the robot’s face) from human participants and consequently created more mutual gaze and eye contact between the two. Moreover, participants demonstrated more coordinated and synchronized multimodal behaviors between speech and gaze when more eye contact was successfully established and maintained. PMID:28966875

  13. Mathematical models of the dynamics of the human eye

    CERN Document Server

    Collins, Richard

    1980-01-01

    A rich and abundant literature has developed during the last half century dealing with mechanical aspects of the eye, mainly from clinical and, experimental points of view. For the most part, workers have attempted to shed light on the complex set of conditions known by the general term glaucoma. These conditions are characterised by an increase in intraocular pressure sufficient to cause de­ generation of the optic disc and concomitant defects in the visual field, which, if not controlled, lead to inevitable permanent blindness. In the United States alone, an estimated 50,000 persons are blind as a result of glaucoma, which strikes about 2% of the population over 40 years of age (Vaughan and Asbury, 1974). An understanding of the underlying mechanisms of glaucoma is hindered by the fact that elevated intraocular pressure, like a runny nose, is but a symptom which may have a variety of causes. Only by turning to the initial pathology can one hope to understand this important class of medical problems.

  14. Dose conversion coefficients for neutron exposure to the lens of the human eye

    Energy Technology Data Exchange (ETDEWEB)

    Manger, Ryan P [ORNL; Bellamy, Michael B [ORNL; Eckerman, Keith F [ORNL

    2011-01-01

    Dose conversion coefficients for the lens of the human eye have been calculated for neutron exposure at energies from 1 x 10{sup -9} to 20 MeV and several standard orientations: anterior-to-posterior, rotational and right lateral. MCNPX version 2.6.0, a Monte Carlo-based particle transport package, was used to determine the energy deposited in the lens of the eye. The human eyeball model was updated by partitioning the lens into sensitive and insensitive volumes as the anterior portion (sensitive volume) of the lens being more radiosensitive and prone to cataract formation. The updated eye model was used with the adult UF-ORNL mathematical phantom in the MCNPX transport calculations.

  15. Expression of human Gaucher disease gene GBA generates neurodevelopmental defects and ER stress in Drosophila eye.

    Directory of Open Access Journals (Sweden)

    Takahiro Suzuki

    Full Text Available Gaucher disease (GD is the most common of the lysosomal storage disorders and is caused by defects in the GBA gene encoding glucocerebrosidase (GlcCerase. The accumulation of its substrate, glucocylceramide (GlcCer is considered the main cause of GD. We found here that the expression of human mutated GlcCerase gene (hGBA that is associated with neuronopathy in GD patients causes neurodevelopmental defects in Drosophila eyes. The data indicate that endoplasmic reticulum (ER stress was elevated in Drosophila eye carrying mutated hGBAs by using of the ER stress markers dXBP1 and dBiP. We also found that Ambroxol, a potential pharmacological chaperone for mutated hGBAs, can alleviate the neuronopathic phenotype through reducing ER stress. We demonstrate a novel mechanism of neurodevelopmental defects mediated by ER stress through expression of mutants of human GBA gene in the eye of Drosophila.

  16. Phase dependencies between longitudinal corneal apex displacement of human eye and cardiovascular system

    Science.gov (United States)

    Danielewska, M.; Kowalska, M.; Kasprzak, H.

    2008-12-01

    Intraocular pressure (IOP) varies quasi-periodically due to blood pulsation in vessels inside the eye globe. This variations cause the eye deformations and displacements of the outer surface of the eye. The aim of this paper is to calculate the correlation between longitudinal corneal apex displacement and cardiovascular activity. Using ultrasound transducer at sampling frequency of 100Hz we have measured longitudinal corneal apex displacement (LCAD) of the left eye for 5 subjects. Synchronically we have registered ECG and blood pulsation signals at the same sampling frequency. Cross-correlation function was applied to investigate dependencies between these signals. To find time shift between LCAD and ECG or pulse, the time window of 3 seconds length have been chosen from all signals and had been shifting with the step of 0.01 seconds from 0 to 7s. For each shift the cross-correlation function and its extrema were calculated in the window area. We have obtained information about extrema position of cross-correlation function and its stability in time for particular subjects. The time shift between LCAD and ECG or pulse is individual feature of each subject. Such calculations may lead us to better understanding of pulse propagation in human eye and creation a non invasive method of eye hemodynamics and ocular diagnosis.

  17. Eye center localization and gaze gesture recognition for human-computer interaction.

    Science.gov (United States)

    Zhang, Wenhao; Smith, Melvyn L; Smith, Lyndon N; Farooq, Abdul

    2016-03-01

    This paper introduces an unsupervised modular approach for accurate and real-time eye center localization in images and videos, thus allowing a coarse-to-fine, global-to-regional scheme. The trajectories of eye centers in consecutive frames, i.e., gaze gestures, are further analyzed, recognized, and employed to boost the human-computer interaction (HCI) experience. This modular approach makes use of isophote and gradient features to estimate the eye center locations. A selective oriented gradient filter has been specifically designed to remove strong gradients from eyebrows, eye corners, and shadows, which sabotage most eye center localization methods. A real-world implementation utilizing these algorithms has been designed in the form of an interactive advertising billboard to demonstrate the effectiveness of our method for HCI. The eye center localization algorithm has been compared with 10 other algorithms on the BioID database and six other algorithms on the GI4E database. It outperforms all the other algorithms in comparison in terms of localization accuracy. Further tests on the extended Yale Face Database b and self-collected data have proved this algorithm to be robust against moderate head poses and poor illumination conditions. The interactive advertising billboard has manifested outstanding usability and effectiveness in our tests and shows great potential for benefiting a wide range of real-world HCI applications.

  18. The effect of human image in B2C website design: an eye-tracking study

    Science.gov (United States)

    Wang, Qiuzhen; Yang, Yi; Wang, Qi; Ma, Qingguo

    2014-09-01

    On B2C shopping websites, effective visual designs can bring about consumers' positive emotional experience. From this perspective, this article developed a research model to explore the impact of human image as a visual element on consumers' online shopping emotions and subsequent attitudes towards websites. This study conducted an eye-tracking experiment to collect both eye movement data and questionnaire data to test the research model. Questionnaire data analysis showed that product pictures combined with human image induced positive emotions among participants, thus promoting their attitudes towards online shopping websites. Specifically, product pictures with human image first produced higher levels of image appeal and perceived social presence, thus stimulating higher levels of enjoyment and subsequent positive attitudes towards the websites. Moreover, a moderating effect of product type was demonstrated on the relationship between the presence of human image and the level of image appeal. Specifically, human image significantly increased the level of image appeal when integrated in entertainment product pictures while this relationship was not significant in terms of utilitarian products. Eye-tracking data analysis further supported these results and provided plausible explanations. The presence of human image significantly increased the pupil size of participants regardless of product types. For entertainment products, participants paid more attention to product pictures integrated with human image whereas for utilitarian products more attention was paid to functional information of products than to product pictures no matter whether or not integrated with human image.

  19. [Efficacy of protein-free calf blood extract for mechanical corneal epithelial defects in human eyes].

    Science.gov (United States)

    Qiu, Xiao-di; Gong, Lan; Sun, Xing-huai; Zhao, Nai-qing; Zhu, Zhao-rong; Li, Yu-min; Yao, Ke; Zhao, Wu-ling

    2008-08-01

    To evaluate the clinical efficacy between protein-free calf blood extract eye drops and recombinant human epidermal growth factor (rhEGF) eye drops for mechanical corneal epithelial defects in human eyes. A multi-center, randomized and double-blind study with a parallel, positive-control designation was carried out from April to November in 2005 at Department of Ophthalmology, Eye Ear Nose and Throat Hospital of Fudan University, Xinhua Hospital of Shanghai Jiaotong University, the First Hospital of Zhejiang University, the Second Hospital of Zhejiang University and Qingdao Municipal Hospital. 240 patients (240 eyes) with confirmed diagnosis of corneal epithelial defects at that six hospitals were enrolled in this study and were randomly arranged into two groups in average. One group (120 eyes) were treated by 20% protein-free calf blood extract eye drops which was defined as the experimental group while the other (120 eyes) by 5000 IU/ml recombinant human epidermal growth factor (rhEGF) eye drops as the positive control group. The drug was delivered in both groups 4 times per day, one drop each time in the 14 days duration. The symptoms and signs were scored and the safety was evaluated on the pre-delivery day, the third post-delivery day (day 3), day 7 and day 14. The variants in the study were tested for the different efficacy and safety between the two drugs using non-inferiority test, paired t-test, Wilcoxon signed-rank test, chi-square test, continuity correction chi-square test, Fisher's exact probabilities, analysis of variance, Cochran-Mantel-Haenszel chi-square test and so on. The criterion for statistical significance was P recombinant human epidermal growth factor group (day 3: X2 = 1.5677, P = 0.4566, day 7: X2 = 1.7152, P = 0.4242, day 14: X2 = 3.0814, P = 0.2142). The total scores of symptoms and signs in experimental group had a obvious descending (6.009 +/- 3.030) compared with the positive control group with a descending of (5.177 +/- 2

  20. Estimating outflow facility through pressure dependent pathways of the human eye.

    Science.gov (United States)

    Smith, David W; Gardiner, Bruce S

    2017-01-01

    We develop and test a new theory for pressure dependent outflow from the eye. The theory comprises three main parameters: (i) a constant hydraulic conductivity, (ii) an exponential decay constant and (iii) a no-flow intraocular pressure, from which the total pressure dependent outflow, average outflow facilities and local outflow facilities for the whole eye may be evaluated. We use a new notation to specify precisely the meaning of model parameters and so model outputs. Drawing on a range of published data, we apply the theory to animal eyes, enucleated eyes and in vivo human eyes, and demonstrate how to evaluate model parameters. It is shown that the theory can fit high quality experimental data remarkably well. The new theory predicts that outflow facilities and total pressure dependent outflow for the whole eye are more than twice as large as estimates based on the Goldman equation and fluorometric analysis of anterior aqueous outflow. It appears likely that this discrepancy can be largely explained by pseudofacility and aqueous flow through the retinal pigmented epithelium, while any residual discrepancy may be due to pathological processes in aged eyes. The model predicts that if the hydraulic conductivity is too small, or the exponential decay constant is too large, then intraocular eye pressure may become unstable when subjected to normal circadian changes in aqueous production. The model also predicts relationships between variables that may be helpful when planning future experiments, and the model generates many novel testable hypotheses. With additional research, the analysis described here may find application in the differential diagnosis, prognosis and monitoring of glaucoma.

  1. Social interactions through the eyes of macaques and humans.

    Directory of Open Access Journals (Sweden)

    Richard McFarland

    Full Text Available Group-living primates frequently interact with each other to maintain social bonds as well as to compete for valuable resources. Observing such social interactions between group members provides individuals with essential information (e.g. on the fighting ability or altruistic attitude of group companions to guide their social tactics and choice of social partners. This process requires individuals to selectively attend to the most informative content within a social scene. It is unclear how non-human primates allocate attention to social interactions in different contexts, and whether they share similar patterns of social attention to humans. Here we compared the gaze behaviour of rhesus macaques and humans when free-viewing the same set of naturalistic images. The images contained positive or negative social interactions between two conspecifics of different phylogenetic distance from the observer; i.e. affiliation or aggression exchanged by two humans, rhesus macaques, Barbary macaques, baboons or lions. Monkeys directed a variable amount of gaze at the two conspecific individuals in the images according to their roles in the interaction (i.e. giver or receiver of affiliation/aggression. Their gaze distribution to non-conspecific individuals was systematically varied according to the viewed species and the nature of interactions, suggesting a contribution of both prior experience and innate bias in guiding social attention. Furthermore, the monkeys' gaze behavior was qualitatively similar to that of humans, especially when viewing negative interactions. Detailed analysis revealed that both species directed more gaze at the face than the body region when inspecting individuals, and attended more to the body region in negative than in positive social interactions. Our study suggests that monkeys and humans share a similar pattern of role-sensitive, species- and context-dependent social attention, implying a homologous cognitive mechanism of

  2. Wave aberration of human eyes and new descriptors of image optical quality and visual performance.

    Science.gov (United States)

    Lombardo, Marco; Lombardo, Giuseppe

    2010-02-01

    The expansion of wavefront-sensing techniques redefined the meaning of refractive error in clinical ophthalmology. Clinical aberrometers provide detailed measurements of the eye's wavefront aberration. The distribution and contribution of each higher-order aberration to the overall wavefront aberration in the individual eye can now be accurately determined and predicted. Using corneal or ocular wavefront sensors, studies have measured the interindividual and age-related changes in the wavefront aberration in the normal population with the goal of optimizing refractive surgery outcomes for the individual. New objective optical-quality metrics would lead to better use and interpretation of newly available information on aberrations in the eye. However, the first metrics introduced, based on sets of Zernike polynomials, is not completely suitable to depict visual quality because they do not directly relate to the quality of the retinal image. Thus, several approaches to describe the real, complex optical performance of human eyes have been implemented. These include objective metrics that quantify the quality of the optical wavefront in the plane of the pupil (ie, pupil-plane metrics) and others that quantify the quality of the retinal image (ie, image-plane metrics). These metrics are derived by wavefront aberration information from the individual eye. This paper reviews the more recent knowledge of the wavefront aberration in human eyes and discusses the image-quality and optical-quality metrics and predictors that are now routinely calculated by wavefront-sensor software to describe the optical and image quality in the individual eye. Copyright 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Controlled delivery of antiangiogenic drug to human eye tissue using a MEMS device

    KAUST Repository

    Pirmoradi, Fatemeh Nazly

    2013-01-01

    We demonstrate an implantable MEMS drug delivery device to conduct controlled and on-demand, ex vivo drug transport to human eye tissue. Remotely operated drug delivery to human post-mortem eyes was performed via a MEMS device. The developed curved packaging cover conforms to the eyeball thereby preventing the eye tissue from contacting the actuating membrane. By pulsed operation of the device, using an externally applied magnetic field, the drug released from the device accumulates in a cavity adjacent to the tissue. As such, docetaxel (DTX), an antiangiogenic drug, diffuses through the eye tissue, from sclera and choroid to retina. DTX uptake by sclera and choroid were measured to be 1.93±0.66 and 7.24±0.37 μg/g tissue, respectively, after two hours in pulsed operation mode (10s on/off cycles) at 23°C. During this period, a total amount of 192 ng DTX diffused into the exposed tissue. This MEMS device shows great potential for the treatment of ocular posterior segment diseases such as diabetic retinopathy by introducing a novel way of drug administration to the eye. © 2013 IEEE.

  4. A Simple Model of the Accommodating Lens of the Human Eye

    Science.gov (United States)

    Oommen, Vinay; Kanthakumar, Praghalathan

    2014-01-01

    The human eye is often discussed as optically equivalent to a photographic camera. The iris is compared with the shutter, the pupil to the aperture, and the retina to the film, and both have lens systems to focus rays of light. Although many similarities exist, a major difference between the two systems is the mechanism involved in focusing an…

  5. Sensory eye irritation in humans exposed to mixtures of volatile organic compounds

    DEFF Research Database (Denmark)

    Hempel-Jørgensen, Anne Hempel; Kjærgaard, Søren K.; Mølhave, Lars

    1999-01-01

    Eight subjects participated in a controlled eyes-only exposure study of human sensory irritation in ocular mucosal tissue. The authors investigated dose-response properties and the additive effects of three mixtures of volatile organic compounds. The dose-response relationships for these mixtures...

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

    NARCIS (Netherlands)

    Barendregt, M.

    2016-01-01

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

  7. Change in the accommodative force on the lens of the human eye with age

    NARCIS (Netherlands)

    Hermans, E.A.; Dubbelman, M.; van der Heijde, G.L.; Heethaar, R.M.

    2008-01-01

    The aim of the study was to determine the age-dependence of the accommodative force on the lens in order to make it clear whether the causes of presbyopia are due to lenticular or extralenticular changes. A finite element model of the lens of an 11-, 29- and 45-year-old human eye was constructed to

  8. Effect of recombinant human epidermal growth factor eye drops and deproteinized calf blood extract eye drops on corneal edema after phacoemulsification

    Directory of Open Access Journals (Sweden)

    Jia Wang

    2017-08-01

    Full Text Available AIM:To compare the effect of recombinant human epidermal growth factor eye drops and deproteinized calf blood extract eye drops on corneal edema after phacoemulsification. METHODS:Totally 72 cases(72 eyesof patients undergoing phacoemulsification were selected and divided into the observation group and the control group by random number table method. After surgery, the observation group were treated with deproteinized calf blood extract eye drops while the control group were treated with recombinant human epidermal growth factor eye drops. The degree of corneal edema, subjective symptom score, corneal endothelium count, changes of corneal thickness and postoperative visual acuity recovery were compared between the two groups at different time points after surgery. RESULTS:Corneal edema in the two groups was significantly milder at 1wk after surgery than that on the 1st day after surgery(PP>0.05. Compared with 1d after surgery, the subjective symptom score and corneal thickness of the two groups significantly decreased on the 7th day after surgery(PPPCONCLUSION:Both of recombinant human epidermal growth factor eye drops and deproteinized calf blood extract eye drops can significantly relieve corneal edema and improve visual acuity of patients after phacoemulsification. However, the latter has obvious advantages over the former in the repair of corneal endothelial cell injury after surgery.

  9. Optimal and human eye movements to clustered low value cues to increase decision rewards during search.

    Science.gov (United States)

    Eckstein, Miguel P; Schoonveld, Wade; Zhang, Sheng; Mack, Stephen C; Akbas, Emre

    2015-08-01

    Rewards have important influences on the motor planning of primates and the firing of neurons coding visual information and action. When eye movements to a target are differentially rewarded across locations, primates execute saccades towards the possible target location with the highest expected value, a product of sensory evidence and potentially earned reward (saccade to maximum expected value model, sMEV). Yet, in the natural world eye movements are not directly rewarded. Their role is to gather information to support subsequent rewarded search decisions and actions. Less is known about the effects of decision rewards on saccades. We show that when varying the decision rewards across cued locations following visual search, humans can plan their eye movements to increase decision rewards. Critically, we report a scenario for which five of seven tested humans do not preferentially deploy saccades to the possible target location with the highest reward, a strategy which is optimal when rewarding eye movements. Instead, these humans make saccades towards lower value but clustered locations when this strategy optimizes decision rewards consistent with the preferences of an ideal Bayesian reward searcher that takes into account the visibility of the target across eccentricities. The ideal reward searcher can be approximated with a sMEV model with pooling of rewards from spatially clustered locations. We also find observers with systematic departures from the optimal strategy and inter-observer variability of eye movement plans. These deviations often reflect multiplicity of fixation strategies that lead to near optimal decision rewards but, for some observers, it relates to suboptimal choices in eye movement planning. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Modelling image formation on the retina and backscattered light in the human eye with cataracts

    Science.gov (United States)

    Kelly-Pérez, Ismael; Bruce, Neil C.; Berriel-Valdos, Luis R.

    2011-05-01

    We develop a computational model to analyze the effect of scattering on image formation in the human eye with cataracts. With this model we compare the scattered light on the retina and in the exit pupil of the eye and find significant differences in the effects observed. We found that the effect of scattering due to the retina reduces the effect of scattering due to cataracts in the second pass, and the most important parameter that affects scattering is the size of the particles.

  11. Approach to HIR (human-oriented information restructuring) using bird's-eye views

    Science.gov (United States)

    Toyota, Koichi; Sekitoh, Makoto; Fujii, Toshiaki; Kimoto, Tadahiko; Tanimoto, Masayuki

    2001-06-01

    In this paper, we describe a system that creates a virtual bird's-eye view from multi-camera images in real-time and its application to 'HIR (Human-Oriented Information Restructuring) system for ITS' we have proposed. In recent years, studies on AHS (Advanced Highway Systems) are seen in many fields. However, there still remains many problems when we try to realize the automated driving, the goal of AHS. To overcome these problems of AHS, we have proposed HIR system, which assists drivers by providing them with integrated and restructured images. The striking point of the proposed system compared with the conventional one is that it is human, not the mechanical cars, that recognizes the situation and controls the car, and for that purpose, we just generate and show easy-to-understand images for human. The step is, integrate and restructure numerous camera images from all driving environment, such as cars and roads, and non-image information like VICS (Vehicle Information and Communication Systems) information. Then pick out the most important information according to the situation and show it in the form of 'image.' This paper proposes a bird's-eye view system as an example of HIR. We describe the algorithm and hardware to create a bird's-eye view in real-time. In the experiment, we show that the bird's-eye view is useful as a driver-assisting image under the situation of right turn at the intersection.

  12. Melanopsin bistability: a fly's eye technology in the human retina.

    Directory of Open Access Journals (Sweden)

    Ludovic S Mure

    Full Text Available In addition to rods and cones, the human retina contains light-sensitive ganglion cells that express melanopsin, a photopigment with signal transduction mechanisms similar to that of invertebrate rhabdomeric photopigments (IRP. Like fly rhodopsins, melanopsin acts as a dual-state photosensitive flip-flop in which light drives both phototransduction responses and chromophore photoregeneration that bestows independence from the retinoid cycle required by rods and cones to regenerate photoresponsiveness following bleaching by light. To explore the hypothesis that melanopsin in humans expresses the properties of a bistable photopigment in vivo we used the pupillary light reflex (PLR as a tool but with methods designed to study invertebrate photoreceptors. We show that the pupil only attains a fully stabilized state of constriction after several minutes of light exposure, a feature that is consistent with typical IRP photoequilibrium spectra. We further demonstrate that previous exposure to long wavelength light increases, while short wavelength light decreases the amplitude of pupil constriction, a fundamental property of IRP difference spectra. Modelling these responses to invertebrate photopigment templates yields two putative spectra for the underlying R and M photopigment states with peaks at 481 nm and 587 nm respectively. Furthermore, this bistable mechanism may confer a novel form of "photic memory" since information of prior light conditions is retained and shapes subsequent responses to light. These results suggest that the human retina exploits fly-like photoreceptive mechanisms that are potentially important for the modulation of non-visual responses to light and highlights the ubiquitous nature of photoswitchable photosensors across living organisms.

  13. An fMRI study of optokinetic nystagmus and smooth-pursuit eye movements in humans.

    Science.gov (United States)

    Konen, Christina S; Kleiser, Raimund; Seitz, Rüdiger J; Bremmer, Frank

    2005-08-01

    Both optokinetic nystagmus (OKN) and smooth-pursuit eye movements (SPEM) are subclasses of so-called slow eye movements. However, optokinetic responses are reflexive whereas smooth pursuit requires the voluntary tracking of a moving target. We used functional magnetic resonance imaging (fMRI) to determine the neural basis of OKN and SPEM, and to uncover whether the two underlying neural systems overlap or are independent at the cortical level. The results showed a largely overlapping neural circuitry. A direct comparison between activity during the execution of OKN and SPEM yielded no oculomotor-related area exclusively dedicated to one or the other eye movement type. Furthermore, the performance of SPEM evoked a bilateral deactivation of the human equivalent of the parietoinsular vestibular cortex. This finding might indicate that the reciprocally inhibitory visual-vestibular interaction involves not only OKN but also SPEM, which are both linked with the encoding of object-motion and self-motion. Moreover, we could show differential activation patterns elicited by look-nystagmus and stare-nystagmus. Look-nystagmus is characterized by large amplitudes and low-frequency resetting eye movements rather resembling SPEM. Look-nystagmus evoked activity in cortical oculomotor centers. By contrast, stare-nystagmus is usually characterized as being more reflexive in nature and as showing smaller amplitudes and higher frequency resetting eye movements. Stare-nystagmus failed to elicit significant signal changes in the same regions as look-nystagmus/SPEM. Thus, less reflexive eye movements correlated with more pronounced signal intensity. Finally, on the basis of a general investigation of slow eye movements, we were interested in a cortical differentiation between subtypes of SPEM. We compared activity associated with predictable and unpredictable SPEM as indicated by appropriate visual cues. In general, predictable and unpredictable SPEM share the same neural network, yet

  14. Lutein and its oxidized forms in eye structures throughout prenatal human development.

    Science.gov (United States)

    Panova, Ina G; Yakovleva, Marina A; Tatikolov, Alexander S; Kononikhin, A S; Feldman, Tatiana B; Poltavtseva, Rimma A; Nikolaev, E N; Sukhikh, Gennady T; Ostrovsky, Mikhail A

    2017-07-01

    The presence of carotenoids in the vitreous body, retina, lens, retinal pigment epithelium together with choroid (hereinafter RPE), and ciliary body and iris together with choroidal stroma (hereinafter CBI) was studied throughout the second trimester of prenatal development of the human eye. It has been found that the vitreous body, retina, and RPE contain lutein and its oxidized forms. Zeaxanthin was not found in the tissues studied. The presence of lutein in the vitreous body is transient and no longer detected after 28 weeks of gestation. Lutein was not detected in the lens and CBI, but its oxidized forms were found. The presence of carotenoids in different tissues of the eye in the course of normal eye development and the antioxidant role of carotenoids are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Acute exposure to evening blue-enriched light impacts on human sleep.

    Science.gov (United States)

    Chellappa, Sarah L; Steiner, Roland; Oelhafen, Peter; Lang, Dieter; Götz, Thomas; Krebs, Julia; Cajochen, Christian

    2013-10-01

    Light in the short wavelength range (blue light: 446-483 nm) elicits direct effects on human melatonin secretion, alertness and cognitive performance via non-image-forming photoreceptors. However, the impact of blue-enriched polychromatic light on human sleep architecture and sleep electroencephalographic activity remains fairly unknown. In this study we investigated sleep structure and sleep electroencephalographic characteristics of 30 healthy young participants (16 men, 14 women; age range 20-31 years) following 2 h of evening light exposure to polychromatic light at 6500 K, 2500 K and 3000 K. Sleep structure across the first three non-rapid eye movement non-rapid eye movement - rapid eye movement sleep cycles did not differ significantly with respect to the light conditions. All-night non-rapid eye movement sleep electroencephalographic power density indicated that exposure to light at 6500 K resulted in a tendency for less frontal non-rapid eye movement electroencephalographic power density, compared to light at 2500 K and 3000 K. The dynamics of non-rapid eye movement electroencephalographic slow wave activity (2.0-4.0 Hz), a functional index of homeostatic sleep pressure, were such that slow wave activity was reduced significantly during the first sleep cycle after light at 6500 K compared to light at 2500 K and 3000 K, particularly in the frontal derivation. Our data suggest that exposure to blue-enriched polychromatic light at relatively low room light levels impacts upon homeostatic sleep regulation, as indexed by reduction in frontal slow wave activity during the first non-rapid eye movement episode. © 2013 European Sleep Research Society.

  16. Modeling the influence of LASIK surgery on optical properties of the human eye

    Science.gov (United States)

    Szul-Pietrzak, Elżbieta; Hachoł, Andrzej; Cieślak, Krzysztof; Drożdż, Ryszard; Podbielska, Halina

    2011-11-01

    The aim was to model the influence of LASIK surgery on the optical parameters of the human eye and to ascertain which factors besides the central corneal radius of curvature and central thickness play the major role in postsurgical refractive change. Ten patients were included in the study. Pre- and postsurgical measurements included standard refraction, anterior corneal curvature and pachymetry. The optical model used in the analysis was based on the Le Grand and El Hage schematic eye, modified by the measured individual parameters of corneal geometry. A substantial difference between eye refractive error measured after LASIK and estimated from the eye model was observed. In three patients, full correction of the refractive error was achieved. However, analysis of the visual quality in terms of spot diagrams and optical transfer functions of the eye optical system revealed some differences in these measurements. This suggests that other factors besides corneal geometry may play a major role in postsurgical refraction. In this paper we investigated whether the biomechanical properties of the eyeball and changes in intraocular pressure could account for the observed discrepancies.

  17. Edge detection of iris of the eye for human biometric identification system

    Directory of Open Access Journals (Sweden)

    Kateryna O. Tryfonova

    2015-03-01

    Full Text Available Method of human biometric identification by iris of the eye is considered as one of the most accurate and reliable methods of identification. Aim of the research is to solve the problem of edge detection of digital image of the human eye iris to be able to implement human biometric identification system by means of mobile device. To achieve this aim the algorithm of edge detection by Canny is considered in work. It consists of the following steps: smoothing, finding gradients, non-maximum suppression, double thresholding with hysteresis. The software implementation of the Canny algorithm is carried out for the Android mobile platform with the use of high level programming language Java.

  18. A Bird’s Eye View of Human Language Evolution

    Science.gov (United States)

    Berwick, Robert C.; Beckers, Gabriël J. L.; Okanoya, Kazuo; Bolhuis, Johan J.

    2012-01-01

    Comparative studies of linguistic faculties in animals pose an evolutionary paradox: language involves certain perceptual and motor abilities, but it is not clear that this serves as more than an input–output channel for the externalization of language proper. Strikingly, the capability for auditory–vocal learning is not shared with our closest relatives, the apes, but is present in such remotely related groups as songbirds and marine mammals. There is increasing evidence for behavioral, neural, and genetic similarities between speech acquisition and birdsong learning. At the same time, researchers have applied formal linguistic analysis to the vocalizations of both primates and songbirds. What have all these studies taught us about the evolution of language? Is the comparative study of an apparently species-specific trait like language feasible? We argue that comparative analysis remains an important method for the evolutionary reconstruction and causal analysis of the mechanisms underlying language. On the one hand, common descent has been important in the evolution of the brain, such that avian and mammalian brains may be largely homologous, particularly in the case of brain regions involved in auditory perception, vocalization, and auditory memory. On the other hand, there has been convergent evolution of the capacity for auditory–vocal learning, and possibly for structuring of external vocalizations, such that apes lack the abilities that are shared between songbirds and humans. However, significant limitations to this comparative analysis remain. While all birdsong may be classified in terms of a particularly simple kind of concatenation system, the regular languages, there is no compelling evidence to date that birdsong matches the characteristic syntactic complexity of human language, arising from the composition of smaller forms like words and phrases into larger ones. PMID:22518103

  19. A Bird's Eye View of Human Language Evolution.

    Science.gov (United States)

    Berwick, Robert C; Beckers, Gabriël J L; Okanoya, Kazuo; Bolhuis, Johan J

    2012-01-01

    COMPARATIVE STUDIES OF LINGUISTIC FACULTIES IN ANIMALS POSE AN EVOLUTIONARY PARADOX: language involves certain perceptual and motor abilities, but it is not clear that this serves as more than an input-output channel for the externalization of language proper. Strikingly, the capability for auditory-vocal learning is not shared with our closest relatives, the apes, but is present in such remotely related groups as songbirds and marine mammals. There is increasing evidence for behavioral, neural, and genetic similarities between speech acquisition and birdsong learning. At the same time, researchers have applied formal linguistic analysis to the vocalizations of both primates and songbirds. What have all these studies taught us about the evolution of language? Is the comparative study of an apparently species-specific trait like language feasible? We argue that comparative analysis remains an important method for the evolutionary reconstruction and causal analysis of the mechanisms underlying language. On the one hand, common descent has been important in the evolution of the brain, such that avian and mammalian brains may be largely homologous, particularly in the case of brain regions involved in auditory perception, vocalization, and auditory memory. On the other hand, there has been convergent evolution of the capacity for auditory-vocal learning, and possibly for structuring of external vocalizations, such that apes lack the abilities that are shared between songbirds and humans. However, significant limitations to this comparative analysis remain. While all birdsong may be classified in terms of a particularly simple kind of concatenation system, the regular languages, there is no compelling evidence to date that birdsong matches the characteristic syntactic complexity of human language, arising from the composition of smaller forms like words and phrases into larger ones.

  20. Thermal behavior of human eye in relation with change in blood perfusion, porosity, evaporation and ambient temperature.

    Science.gov (United States)

    Rafiq, Aasma; Khanday, M A

    2016-12-01

    Extreme environmental and physiological conditions present challenges for thermal processes in body tissues including multi-layered human eye. A mathematical model has been formulated in this direction to study the thermal behavior of the human eye in relation with the change in blood perfusion, porosity, evaporation and environmental temperatures. In this study, a comprehensive thermal analysis has been performed on the multi-layered eye using Pennes' bio-heat equation with appropriate boundary and interface conditions. The variational finite element method and MATLAB software were used for the solution purpose and simulation of the results. The thermoregulatory effect due to blood perfusion rate, porosity, ambient temperature and evaporation at various regions of human eye was illustrated mathematically and graphically. The main applications of this model are associated with the medical sciences while performing laser therapy and other thermoregulatory investigation on human eye. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Category processing and the human likeness dimension of the Uncanny Valley Hypothesis: Eye-tracking data

    Directory of Open Access Journals (Sweden)

    Marcus eCheetham

    2013-03-01

    Full Text Available The Uncanny Valley Hypothesis (Mori, 1970 predicts that perceptual difficulty distinguishing between a humanlike object (e.g., lifelike prosthetic hand, mannequin and its human counterpart evokes negative affect. Research has focussed on affect, with inconsistent results, but little is known about how objects along the hypothesis’ dimension of human likeness (DHL are actually perceived. This study used morph continua based on human and highly realistic computer-generated (avatar faces to represent the DHL. Total number and dwell time of fixations to facial features were recorded while participants (N=60 judged avatar vs. human category membership of the faces in a forced choice categorisation task. Fixation and dwell data confirmed the face feature hierarchy (eyes, nose and mouth in this order of importance across the DHL. There were no further findings for fixation. A change in the relative importance of these features was found for dwell time, with greater preferential processing of eyes and mouth of categorically ambiguous faces compared with unambiguous avatar faces. There were no significant differences between ambiguous and human faces. These findings applied for men and women, though women generally dwelled more on the eyes to the disadvantage of the nose. The mouth was unaffected by gender. In summary, the relative importance of facial features changed on the DHL’s nonhuman side as a function of categorisation ambiguity. This change was indicated by dwell time only, suggesting greater depth of perceptual processing of the eyes and mouth of ambiguous faces compared with these features in unambiguous avatar faces.

  2. Limitations in assessing nerve growth factor levels in aqueous humor samples from human eyes

    Directory of Open Access Journals (Sweden)

    Chalam Kakarla V

    2008-06-01

    Full Text Available Abstract Background Nerve growth factor (NGF helps in the healing and survival of ganglion cells, photoreceptors, and optic nerve after injury and has been implicated to have a role in pathophysiology of glaucoma. So far, in animal studies, injury to iris in vitro has revealed an increase in NGF levels in aqueous. There is a great interest in investigating the levels of NGF in human aqueous in glaucomatous eyes, as suggested by animal studies, to gain a better understanding of the pathophysiology of glaucoma. Findings In this study, we examined the presence of NGF levels in aqueous humor collected from human eyes and the limitations in determining the NGF levels in human samples. NGF was assessed by ELISA immunoassay in undiluted aqueous samples collected from 32 consecutive patients undergoing surgery for cataract (control or primary open angle glaucoma (POAG. Recombinant NGF was used as positive control. NGF levels were below undetectable levels in aqueous humor from eyes with POAG and controls by immunoassay. Less than 10% of samples had detectable NGF levels and these were considered outliers. Conclusion Our result highlights the undetectable levels of NGF in human aqueous samples.

  3. Effect of human milk as a treatment for dry eye syndrome in a mouse model.

    Science.gov (United States)

    Diego, Jose L; Bidikov, Luke; Pedler, Michelle G; Kennedy, Jeffrey B; Quiroz-Mercado, Hugo; Gregory, Darren G; Petrash, J Mark; McCourt, Emily A

    Dry eye syndrome (DES) affects millions of people worldwide. Homeopathic remedies to treat a wide variety of ocular diseases have previously been documented in the literature, but little systematic work has been performed to validate the remedies' efficacy using accepted laboratory models of disease. The purpose of this study was to evaluate the efficacy of human milk and nopal cactus (prickly pear), two widely used homeopathic remedies, as agents to reduce pathological markers of DES. The previously described benzalkonium chloride (BAK) dry eye mouse model was used to study the efficacy of human milk and nopal cactus (prickly pear). BAK (0.2%) was applied to the mouse ocular surface twice daily to induce dry eye pathology. Fluorescein staining was used to verify that the animals had characteristic signs of DES. After induction of DES, the animals were treated with human milk (whole and fat-reduced), nopal, nopal extract derivatives, or cyclosporine four times daily for 7 days. Punctate staining and preservation of corneal epithelial thickness, measured histologically at the end of treatment, were used as indices of therapeutic efficacy. Treatment with BAK reduced the mean corneal epithelial thickness from 36.77±0.64 μm in the control mice to 21.29±3.2 μm. Reduction in corneal epithelial thickness was largely prevented by administration of whole milk (33.2±2.5 μm) or fat-reduced milk (36.1±1.58 μm), outcomes that were similar to treatment with cyclosporine (38.52±2.47 μm), a standard in current dry eye therapy. In contrast, crude or filtered nopal extracts were ineffective at preventing BAK-induced loss of corneal epithelial thickness (24.76±1.78 μm and 27.99±2.75 μm, respectively), as were solvents used in the extraction of nopal materials (26.53±1.46 μm for ethyl acetate, 21.59±5.87 μm for methanol). Epithelial damage, as reflected in the punctate scores, decreased over 4 days of treatment with whole and fat-reduced milk but continued to

  4. A Novel Fluorescent Lipid Probe for Dry Eye: Retrieval by Tear Lipocalin in Humans

    Science.gov (United States)

    Yeh, Po-Ting; Casey, Richard; Glasgow, Ben J.

    2013-01-01

    Purpose. A fluorescent probe was used to identify mucin-depleted areas on the ocular surface and to test the hypothesis that tear lipocalin retrieves lipids from the eyes of normal and dry eye subjects. Methods. Fluorescein-labeled octadecyl ester, FODE, was characterized by mass spectrometry and absorbance spectrophotometry. The use of FODE to define mucin defects was studied with impression membranes under conditions that selectively deplete mucin. The kinetics of FODE removal from the ocular surface were analyzed by sampling tears from control and dry eye patients at various times. The tear protein–FODE complexes were isolated by gel filtration and ion exchange chromatographies, monitored with absorption and fluorescent spectroscopies, and analyzed by gel electrophoresis. Immunoprecipitation verified FODE complexed to tear lipocalin in tears. Results. FODE exhibits an isosbestic point at 473 nm, pKa of 7.5, and red shift relative to fluorescein. The low solubility of FODE in buffer is enhanced with 1% Tween 80 and ethanol. FODE adheres to the ocular surface of dry eye patients. FODE produces visible staining at the contact sites of membranes, which correlates with removal of mucin. Despite the fact that tear lipocalin is reduced in dry eye patients, FODE removal follows similar rapid exponential decay functions for all subjects. FODE is bound to tear lipocalin in tears. Conclusions. Tear lipocalin retrieves lipid rapidly from the human ocular surface in mild to moderate dry eye disease and controls. With improvements in solubility, FODE may have potential as a fluorescent probe to identify mucin-depleted areas. PMID:23361507

  5. Elastic hysteresis in human eyes is an age-dependent value.

    Science.gov (United States)

    Ishii, Kotaro; Saito, Kei; Kameda, Toshihiro; Oshika, Tetsuro

    2013-01-01

    The elastic hysteresis phenomenon is observed when cyclic loading is applied to a viscoelastic system. The purpose of this study was to quantitatively evaluate elastic hysteresis in living human eyes against an external force. Prospective case series. Twenty-four eyes of 24 normal human subjects (mean age: 41.5 ± 10.6 years) were recruited. A non-contact tonometry process was recorded with a high-speed camera. Central corneal thickness, corneal thickness at 4 mm from the centre, corneal curvature and anterior chamber depth were measured. Intraocular pressure was also measured using Goldmann applanation tonometry and dynamic contour tonometer. Energy loss due to elastic hysteresis was calculated and graphed. The mean central corneal thickness was 552.5 ± 36.1 µm, corneal curvature was 7.84 ± 0.26 mm and anterior chamber depth was 2.83 ± 0.29 mm. The mean Goldmann applanation tonometry-intraocular pressure was 14.2 ± 2.7 mmHg and dynamic contour tonometer-intraocular pressure was 16.3 ± 3.5 mmHg. The mean energy loss due to elastic hysteresis was 3.90 × 10(-6) ± 2.49 × 10(-6) Nm. Energy loss due to elastic hysteresis correlated significantly with age (Pearson correlation coefficient = 0.596, P = .0016). There were no significant correlations between energy loss due to elastic hysteresis and other measurements. Energy loss due to elastic hysteresis in the eyes of subjects was found to positively correlate with age, independent of anterior eye structure or intraocular pressure. Therefore, it is believed that the viscosity of the eye increases with age. © 2012 The Authors. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.

  6. Apnea-Induced Rapid Eye Movement Sleep Disruption Impairs Human Spatial Navigational Memory

    OpenAIRE

    Varga, Andrew W.; Kishi, Akifumi; Mantua, Janna; Lim, Jason; Koushyk, Viachaslau; Leibert, David P.; Osorio, Ricardo S.; Rapoport, David M.; Ayappa, Indu

    2014-01-01

    Hippocampal electrophysiology and behavioral evidence support a role for sleep in spatial navigational memory, but the role of particular sleep stages is less clear. Although rodent models suggest the importance of rapid eye movement (REM) sleep in spatial navigational memory, a similar role for REM sleep has never been examined in humans. We recruited subjects with severe obstructive sleep apnea (OSA) who were well treated and adherent with continuous positive airway pressure (CPAP). Restric...

  7. Optics of the human cornea influence the accuracy of stereo eye-tracking methods: a simulation study

    NARCIS (Netherlands)

    Barsingerhorn, A.D.; Boonstra, F.N.; Goossens, H.H.L.M.

    2017-01-01

    Current stereo eye-tracking methods model the cornea as a sphere with one refractive surface. However, the human cornea is slightly aspheric and has two refractive surfaces. Here we used ray-tracing and the Navarro eye-model to study how these optical properties affect the accuracy of different

  8. Visual exploration patterns of human figures in action: An eye tracker study with art paintings

    Directory of Open Access Journals (Sweden)

    Daniela eVillani

    2015-10-01

    Full Text Available Art exploration is a complex process conditioned by factors at different levels and includes both basic visual principles and complex cognitive factors. The human figure is considered a critical factor attracting the attention in art painting. Using an eye-tracking methodology, the goal of this study was to explore different elements of the human figure performing an action (face and body parts in action in complex social scenes characterized by different levels of social interaction between agents depicted in scenes (individual vs. social. The sample included 44 laypersons, and the stimuli consisted of 10 fine art paintings representing the figurative style of classical art. The results revealed different scanning patterns of the human figure elements related to the level of social interaction of agents depicted in the scene. The agents’ face attracted eye movements in social interaction scenes while the agents’ body parts attracted eye movements only when the agents were involved in individual actions. These processes were confirmed specifically in participants with high empathic abilities who became immediately fixated on faces to develop a mimetic engagement with other agents. Future studies integrating other measures would help confirm the results obtained and strengthen their implication for embodiment processes.

  9. Visual exploration patterns of human figures in action: an eye tracker study with art paintings

    Science.gov (United States)

    Villani, Daniela; Morganti, Francesca; Cipresso, Pietro; Ruggi, Simona; Riva, Giuseppe; Gilli, Gabriella

    2015-01-01

    Art exploration is a complex process conditioned by factors at different levels and includes both basic visual principles and complex cognitive factors. The human figure is considered a critical factor attracting the attention in art painting. Using an eye-tracking methodology, the goal of this study was to explore different elements of the human figure performing an action (face and body parts in action) in complex social scenes characterized by different levels of social interaction between agents depicted in scenes (individual vs. social). The sample included 44 laypersons, and the stimuli consisted of 10 fine art paintings representing the figurative style of classical art. The results revealed different scanning patterns of the human figure elements related to the level of social interaction of agents depicted in the scene. The agents’ face attracted eye movements in social interaction scenes while the agents’ body parts attracted eye movements only when the agents were involved in individual actions. These processes were confirmed specifically in participants with high empathic abilities who became immediately fixated on faces to develop a mimetic engagement with other agents. Future studies integrating other measures would help confirm the results obtained and strengthen their implication for embodiment processes. PMID:26579021

  10. Mathematical modeling of laser linear thermal effects on the anterior layer of the human eye

    Science.gov (United States)

    Rahbar, Sahar; Shokooh-Saremi, Mehrdad

    2018-02-01

    In this paper, mathematical analysis of thermal effects of excimer lasers on the anterior side of the human eye is presented, where linear effect of absorption by the human eye is considered. To this end, Argon Fluoride (ArF) and Holmium:Yttrium-Aluminum-Garent (Ho:YAG) lasers are utilized in this investigation. A three-dimensional model of the human eye with actual dimensions is employed and finite element method (FEM) is utilized to numerically solve the governing (Penne) heat transfer equation. The simulation results suggest the corneal temperature of 263 °C and 83.4 °C for ArF and Ho:YAG laser radiations, respectively, and show less heat penetration depth in comparison to the previous reports. Moreover, the heat transfer equation is solved semi-analytically in one-dimension. It is shown that the exploited simulation results are also consistent with those derived from the semi-analytical solution of the Penne heat transfer equation for both types of laser radiations.

  11. Extralenticular and lenticular aspects of accommodation and presbyopia in human versus monkey eyes.

    Science.gov (United States)

    Croft, Mary Ann; McDonald, Jared P; Katz, Alexander; Lin, Ting-Li; Lütjen-Drecoll, Elke; Kaufman, Paul L

    2013-07-26

    To determine if the accommodative forward movements of the vitreous zonule and lens equator occur in the human eye, as they do in the rhesus monkey eye; to investigate the connection between the vitreous zonule posterior insertion zone and the posterior lens equator; and to determine which components-muscle apex width, lens thickness, lens equator position, vitreous zonule, circumlental space, and/or other intraocular dimensions, including those stated in the objectives above-are most important in predicting accommodative amplitude and presbyopia. Accommodation was induced pharmacologically in 12 visually normal human subjects (ages 19-65 years) and by midbrain electrical stimulation in 11 rhesus monkeys (ages 6-27 years). Ultrasound biomicroscopy imaged the entire ciliary body, anterior and posterior lens surfaces, and the zonule. Relevant distances were measured in the resting and accommodated eyes. Stepwise regression analysis determined which variables were the most important predictors. The human vitreous zonule and lens equator move forward (anteriorly) during accommodation, and their movements decline with age, as in the monkey. Over all ages studied, age could explain accommodative amplitude, but not as well as accommodative lens thickening and resting muscle apex thickness did together. Accommodative change in distances between the vitreous zonule insertion zone and the posterior lens equator or muscle apex were important for predicting accommodative lens thickening. Our findings quantify the movements of the zonule and ciliary muscle during accommodation, and identify their age-related changes that could impact the optical change that occurs during accommodation and IOL function.

  12. Judgment of the humanness of an interlocutor is in the eye of the beholder.

    Science.gov (United States)

    Lortie, Catherine L; Guitton, Matthieu J

    2011-01-01

    Despite tremendous advances in artificial language synthesis, no machine has so far succeeded in deceiving a human. Most research focused on analyzing the behavior of "good" machine. We here choose an opposite strategy, by analyzing the behavior of "bad" humans, i.e., humans perceived as machine. The Loebner Prize in Artificial Intelligence features humans and artificial agents trying to convince judges on their humanness via computer-mediated communication. Using this setting as a model, we investigated here whether the linguistic behavior of human subjects perceived as non-human would enable us to identify some of the core parameters involved in the judgment of an agents' humanness. We analyzed descriptive and semantic aspects of dialogues in which subjects succeeded or failed to convince judges of their humanness. Using cognitive and emotional dimensions in a global behavioral characterization, we demonstrate important differences in the patterns of behavioral expressiveness of the judges whether they perceived their interlocutor as being human or machine. Furthermore, the indicators of interest displayed by the judges were predictive of the final judgment of humanness. Thus, we show that the judgment of an interlocutor's humanness during a social interaction depends not only on his behavior, but also on the judge himself. Our results thus demonstrate that the judgment of humanness is in the eye of the beholder.

  13. Intraocular Telescopic System Design: Optical and Visual Simulation in a Human Eye Model.

    Science.gov (United States)

    Zoulinakis, Georgios; Ferrer-Blasco, Teresa

    2017-01-01

    Purpose. To design an intraocular telescopic system (ITS) for magnifying retinal image and to simulate its optical and visual performance after implantation in a human eye model. Methods. Design and simulation were carried out with a ray-tracing and optical design software. Two different ITS were designed, and their visual performance was simulated using the Liou-Brennan eye model. The difference between the ITS was their lenses' placement in the eye model and their powers. Ray tracing in both centered and decentered situations was carried out for both ITS while visual Strehl ratio (VSOTF) was computed using custom-made MATLAB code. Results. The results show that between 0.4 and 0.8 mm of decentration, the VSOTF does not change much either for far or near target distances. The image projection for these decentrations is in the parafoveal zone, and the quality of the image projected is quite similar. Conclusion. Both systems display similar quality while they differ in size; therefore, the choice between them would need to take into account specific parameters from the patient's eye. Quality does not change too much between 0.4 and 0.8 mm of decentration for either system which gives flexibility to the clinician to adjust decentration to avoid areas of retinal damage.

  14. Intraocular Telescopic System Design: Optical and Visual Simulation in a Human Eye Model

    Directory of Open Access Journals (Sweden)

    Georgios Zoulinakis

    2017-01-01

    Full Text Available Purpose. To design an intraocular telescopic system (ITS for magnifying retinal image and to simulate its optical and visual performance after implantation in a human eye model. Methods. Design and simulation were carried out with a ray-tracing and optical design software. Two different ITS were designed, and their visual performance was simulated using the Liou-Brennan eye model. The difference between the ITS was their lenses’ placement in the eye model and their powers. Ray tracing in both centered and decentered situations was carried out for both ITS while visual Strehl ratio (VSOTF was computed using custom-made MATLAB code. Results. The results show that between 0.4 and 0.8 mm of decentration, the VSOTF does not change much either for far or near target distances. The image projection for these decentrations is in the parafoveal zone, and the quality of the image projected is quite similar. Conclusion. Both systems display similar quality while they differ in size; therefore, the choice between them would need to take into account specific parameters from the patient’s eye. Quality does not change too much between 0.4 and 0.8 mm of decentration for either system which gives flexibility to the clinician to adjust decentration to avoid areas of retinal damage.

  15. Peripapillary distribution of Muller cells within the retinal nerve fiber layer in human eyes.

    Science.gov (United States)

    Frenkel, Shahar; Goshen, Gal; Leach, Lu; Pe'er, Jacob; Mimouni, Michael; Blumenthal, Eytan Z

    2018-01-01

    The purpose of this study was to describe the distribution of Muller cell within the peripapillary retinal nerve fiber layer (RNFL) in human eyes. Eleven unpaired normal postmortem eyes were recruited into this study. Each eye was sectioned using the "umbrella technique" to obtain a concentric peripapillary ring centered on the optic disc, with a diameter of 3.0 mm. Immunohistochemistry with anti- CRALBP stained Muller cell within each ring. The RNFL thickness measurements around the peripapillary ring were: 262.5, 339.4, 285.4 and 347.5 μm for the temporal, superior, nasal and inferior quadrants, respectively. Muller cell were found to be unevenly distributed in the peripapillary RNFL of normal eyes. The relative Muller cell staining to the thickness of each measured segment (16.6%, 15.2%, 21.3%, and 17.9% for the temporal, superior, nasal and inferior quadrants, respectively) showed a significant increase in the nasal quadrant. The RNFL thickness measurements obtained using imaging techniques reflect the amount of axonal tissue present in this layer. In this study we highlight that around 20% of RNFL thickness is composed of non-axonal contents which do not represent neuronal tissue, nor are they necessarily lost in the glaucomatous process. More so, the ratio of the Muller cell component to the total RNFL thickness varies around the peripapillary RNFL ring, demonstrating the lowest relative content of Muller cell superiorly and the highest content nasally. Further studies should compare the amount and distribution of Muller cell in normal versus glaucomatous eyes. Copyright © 2017. Published by Elsevier Ltd.

  16. 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...

  17. Will vaccination against human papillomavirus prevent eye disease? A review of the evidence.

    Science.gov (United States)

    Hughes, D S; Powell, N; Fiander, A N

    2008-04-01

    The role of human papillomavirus (HPV) infection in eye disease is controversial. However, a recent case illustrates the possible role of HPV in conjunctival squamous carcinoma and the potentially devastating effects of this disease. The development of two vaccines to prevent infection with HPV types most commonly associated with anogenital cancers has led to debate about the pros and cons of a national immunisation programme to prevent cervical cancer. The introduction of such a vaccination programme may have an additional beneficial effect on the occurrence of some head and neck, including ocular, cancers. This review discusses the nature of papillomaviruses, mechanisms of infection and carcinogenesis, the possible role of HPV in eye disease, and finally the likely impact of the new prophylactic vaccines.

  18. The effect on human eye blink frequency of exposure to limonene oxidation products and methacrolein

    DEFF Research Database (Denmark)

    Nøjgaard, Jacob Klenø; Christensen, Karl Bang; Wolkoff, Peder

    2005-01-01

    oxidation product methacrolein using blink frequency (BF) as a measure of trigeminal stimulation of the human eye. Ten male subjects averaging 43 (standard deviation 10.5) years were exposed for 20 min to LOPs, methacrolein, and clean air, respectively. A baseline BF was measured prior to and following each...... to LOPs and methacrolein compared to the baseline of clean air, and the findings coincided with weak eye irritation symptoms. Lowest observed effect levels were 286 ppb methacrolein and a 10-min-old LOPs mixture of initially 92 ppb limonene and 101 ppb ozone (O3), which increased the BF comparably by 18...... and limonene concentrations, which are close to high-end values measured in indoor settings. The effects may be exacerbated by low RH....

  19. Nonpenetrating glaucoma surgery using the CO2 laser: experimental studies in human cadaver eyes

    Science.gov (United States)

    Assia, Ehud I.; Barequet, Irina S.; Rosner, Mordechai; Belkin, Michael

    2001-06-01

    Non-penetrating trabeculectomy (NPT) is a potential replacement to conventional trabeculectomy, as it eliminates the necessity of penetrating the eye which is the cause of most of the complications entailed by the latter operation. NPT however, requires considerable surgical skill, is time consuming and entails complications of its own. We have shown that it can be easily performed by using the CO2 laser to ablate the sclera and corneoscleral tissues to the required depth. The use of the CO2 laser eliminates the danger of inadvertent perforation, a common complication of NPT as the tissue ablation ceases when the end-point of the operation, the aqueous humor percolation, is reached. Our experiments, performed on animal and human cadaver eyes showed that CO2 laser NPT rapid is easily mastered and performed rapid and eliminates almost completely the risk of complications.

  20. Defining the Human Macula Transcriptome and Candidate Retinal Disease Genes UsingEyeSAGE

    Science.gov (United States)

    Rickman, Catherine Bowes; Ebright, Jessica N.; Zavodni, Zachary J.; Yu, Ling; Wang, Tianyuan; Daiger, Stephen P.; Wistow, Graeme; Boon, Kathy; Hauser, Michael A.

    2009-01-01

    Purpose To develop large-scale, high-throughput annotation of the human macula transcriptome and to identify and prioritize candidate genes for inherited retinal dystrophies, based on ocular-expression profiles using serial analysis of gene expression (SAGE). Methods Two human retina and two retinal pigment epithelium (RPE)/choroid SAGE libraries made from matched macula or midperipheral retina and adjacent RPE/choroid of morphologically normal 28- to 66-year-old donors and a human central retina longSAGE library made from 41- to 66-year-old donors were generated. Their transcription profiles were entered into a relational database, EyeSAGE, including microarray expression profiles of retina and publicly available normal human tissue SAGE libraries. EyeSAGE was used to identify retina- and RPE-specific and -associated genes, and candidate genes for retina and RPE disease loci. Differential and/or cell-type specific expression was validated by quantitative and single-cell RT-PCR. Results Cone photoreceptor-associated gene expression was elevated in the macula transcription profiles. Analysis of the longSAGE retina tags enhanced tag-to-gene mapping and revealed alternatively spliced genes. Analysis of candidate gene expression tables for the identified Bardet-Biedl syndrome disease gene (BBS5) in the BBS5 disease region table yielded BBS5 as the top candidate. Compelling candidates for inherited retina diseases were identified. Conclusions The EyeSAGE database, combining three different gene-profiling platforms including the authors’ multidonor-derived retina/RPE SAGE libraries and existing single-donor retina/RPE libraries, is a powerful resource for definition of the retina and RPE transcriptomes. It can be used to identify retina-specific genes, including alternatively spliced transcripts and to prioritize candidate genes within mapped retinal disease regions. PMID:16723438

  1. FDTD computation of human eye exposure to ultra-wideband electromagnetic pulses.

    Science.gov (United States)

    Simicevic, Neven

    2008-03-21

    With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29 and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of 0.1 mm and an arbitrary precision in the description of its dielectric properties in terms of the Debye model. New results show that the interaction of UWB pulses with the eye tissues exhibits the same properties as the interaction of the continuous electromagnetic waves (CWs) with the frequencies from the pulse's frequency spectrum. It is also shown that under the same exposure conditions the exposure to UWB pulses is from one to many orders of magnitude safer than the exposure to CW.

  2. FDTD computation of human eye exposure to ultra-wideband electromagnetic pulses

    Energy Technology Data Exchange (ETDEWEB)

    Simicevic, Neven [Center for Applied Physics Studies, Louisiana Tech University, Ruston, LA 71272 (United States)], E-mail: neven@phys.latech.edu

    2008-03-21

    With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29 and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of 0.1 mm and an arbitrary precision in the description of its dielectric properties in terms of the Debye model. New results show that the interaction of UWB pulses with the eye tissues exhibits the same properties as the interaction of the continuous electromagnetic waves (CWs) with the frequencies from the pulse's frequency spectrum. It is also shown that under the same exposure conditions the exposure to UWB pulses is from one to many orders of magnitude safer than the exposure to CW.

  3. Binocular open-view system to perform estimations of aberrations and scattering in the human eye.

    Science.gov (United States)

    García-Guerra, Carlos E; Aldaba, Mikel; Arjona, Montserrat; Pujol, Jaume

    2015-11-10

    We present a system that integrates a double-pass (DP) instrument and a Hartmann-Shack (HS) wavefront sensor to provide information not only on aberrations, but also on the scattering that occurs in the human eye. A binocular open-view design permits evaluations to be made under normal viewing conditions. Furthermore, the system is able to compensate for both the spherical and astigmatic refractive errors that occur during measurements by using devices with configurable optical power. The DP and HS techniques provide comparable data after estimating wavefront slopes with respect to the intersections of an ideal grid and compensating for residual errors caused by the optical defects of the measuring system. Once comparable data is obtained, it is possible to use this combined manner of assessment to provide information on scattering. Measurements in an artificial eye suggest that the characteristics of the ocular fundus may induce deviations of DP with respect to the HS data. These differences were quantified in terms of the modulation transfer function in young, healthy eyes measured in infrared light to demonstrate the potential use of the system in visual optics studies.

  4. Postural And Eye-Positional Effects On Human Biting Force: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Altay Tabancacı

    2012-06-01

    Full Text Available Muscle groups affected on biting force are called temporal muscle as a major and masseter muscle as a minor. According to the human posture stability, forces of these muscles vary with the force directions. In this case, experimental investigation is strictly important such that biting force under different postural and eye- positional situations is changed. In this study, seven-male and seven-female within the age-range of 17-24 are considered corresponding to having with restorated molar tooth and without that type of tooth. With the help of specially designed biting fork, different posture- and eye-positions are investigated for experimental biting force analysis. Changes in eye-positions are not indicated significant difference for all postural positions. On one hand, it is obtained that biting force of no-filling tooth in men becomes maximum if facial muscles give full effort to biting. On the other hand, effect of facial muscles for women is not clearly noticed depending on the postural differences.

  5. Learning from biotechnology: milestones in the prenatal engineering of an intelligent optical sensor--the human eye

    Science.gov (United States)

    Lauinger, Norbert

    2001-10-01

    The analysis of the prenatal engineering of the human brain and more specifically that of the human eye may encourage new interpretations and better understanding of cortical processors and lead to better ideas about how to build optical sensors. What human vision at its first processing stages realizes is an adaptive transformation of physical parameters from an outer 4D-spatiotemporal into an inner psychological world or its reciprocal projection and construction of an illusionary (inner or outer) world. The description of some of the most remarkable steps in the development of the human eye before birth, very critical for the optical functionalities in vision, will illustrate the new interpretations.

  6. Animal and human responses to UVA and UVB[UV; Skin; Eye; Carcinogenesis; Immune response

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, R.; Cridland, N.; Kowalczuk, C

    1997-12-01

    Ultraviolet radiation (UVR) comprises the most energetic region of the optical radiation spectrum and is able to induce photochemical changes in the superficial tissues of animals and people which can lead to various acute or chronic adverse health effects. The evidence concerning experimental studies of animals and, where available, volunteers of the effects of occupationally relevant wavelengths (principally UVB, 280-315 rim, and UVA, 315-400 nm) has been reviewed. Experimental studies on animals indicate that exposure to UVR elicits transient (acute) and long-lasting (chronic) effects in the skin and the eye, the severity of which increases in proportion to the exposure. Transient responses have also been investigated in human volunteers and these include adaptive changes such as immediate pigment darkening, melanogenesis and epidermal hyperplasia, and inflammatory responses such as erythema in the skin and keratitis and conjunctivitis in the eye. Irreversible, long-lasting changes also occur following exposure; these include photoageing of the skin, and the development of cataracts in the lens of the eye. Animal studies show that UVR can act either as a complete carcinogen, capable of inducing tumours when applied by itself, or as a co-carcinogen acting in combination with tumour initiators and promoters. The interaction of UVR with the immune system is complex. Exposure to UVR affects the immune system, depressing certain types of cell-mediated antigen-specific responses. Variable immunosuppressive effects have also been reported in humans. In addition, exogenous chemical sensitisers can initiate phototoxic or photoallergic responses in humans and animals; these can precede the development of more persistent idiopathic photodermatoses in which the sensitiser may be an endogenous chemical or antigen. Recommendations for further research are made. (author)

  7. Optics of the human cornea influence the accuracy of stereo eye-tracking methods: a simulation study.

    Science.gov (United States)

    Barsingerhorn, A D; Boonstra, F N; Goossens, H H L M

    2017-02-01

    Current stereo eye-tracking methods model the cornea as a sphere with one refractive surface. However, the human cornea is slightly aspheric and has two refractive surfaces. Here we used ray-tracing and the Navarro eye-model to study how these optical properties affect the accuracy of different stereo eye-tracking methods. We found that pupil size, gaze direction and head position all influence the reconstruction of gaze. Resulting errors range between ± 1.0 degrees at best. This shows that stereo eye-tracking may be an option if reliable calibration is not possible, but the applied eye-model should account for the actual optics of the cornea.

  8. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models.

    Science.gov (United States)

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-11

    In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3 mm of pupil diameter and from 0 to out-of-focus blur were collected and graphed. MTF values, measured at 555 nm of monochromatic light under each spatial frequency, were significantly higher than the values measured at 470 to 650 nm of polychromatic light. The influences of chromatic aberration on MTF values decreased with the increase in IOL diopter when the spatial frequency was ≤12 c/d, while increased effects were observed when the spatial frequency was ≥15 c/d. The MTF values of each IOL eye model were significantly lower than the MTF values of the Liou-Brennan eye models when measured at 555 nm of monochromatic light and at 470 to 650 nm of polychromatic light. The MTF values were also found to be increased with the increase in IOL diopter. With higher diopters of IOLs, the central thickness increased accordingly, which could have created increased chromatic aberration and decreased the retinal image quality. To improve the postoperative visual quality, IOLs with lower chromatic aberration should be selected for patients with short axial lengths.

  9. A practical efficient human computer interface based on saccadic eye movements for people with disabilities.

    Science.gov (United States)

    Soltani, Sima; Mahnam, Amin

    2016-03-01

    Human computer interfaces (HCI) provide new channels of communication for people with severe motor disabilities to state their needs, and control their environment. Some HCI systems are based on eye movements detected from the electrooculogram. In this study, a wearable HCI, which implements a novel adaptive algorithm for detection of saccadic eye movements in eight directions, was developed, considering the limitations that people with disabilities have. The adaptive algorithm eliminated the need for calibration of the system for different users and in different environments. A two-stage typing environment and a simple game for training people with disabilities to work with the system were also developed. Performance of the system was evaluated in experiments with the typing environment performed by six participants without disabilities. The average accuracy of the system in detecting eye movements and blinking was 82.9% at first tries with an average typing rate of 4.5cpm. However an experienced user could achieve 96% accuracy and 7.2cpm typing rate. Moreover, the functionality of the system for people with movement disabilities was evaluated by performing experiments with the game environment. Six people with tetraplegia and significant levels of speech impairment played with the computer game several times. The average success rate in performing the necessary eye movements was 61.5%, which increased significantly with practice up to 83% for one participant. The developed system is 2.6×4.5cm in size and weighs only 15g, assuring high level of comfort for the users. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. The Way Dogs (Canis familiaris Look at Human Emotional Faces Is Modulated by Oxytocin. An Eye-Tracking Study

    Directory of Open Access Journals (Sweden)

    Anna Kis

    2017-10-01

    Full Text Available Dogs have been shown to excel in reading human social cues, including facial cues. In the present study we used eye-tracking technology to further study dogs’ face processing abilities. It was found that dogs discriminated between human facial regions in their spontaneous viewing pattern and looked most to the eye region independently of facial expression. Furthermore dogs played most attention to the first two images presented, afterwards their attention dramatically decreases; a finding that has methodological implications. Increasing evidence indicates that the oxytocin system is involved in dogs’ human-directed social competence, thus as a next step we investigated the effects of oxytocin on processing of human facial emotions. It was found that oxytocin decreases dogs’ looking to the human faces expressing angry emotional expression. More interestingly, however, after oxytocin pre-treatment dogs’ preferential gaze toward the eye region when processing happy human facial expressions disappears. These results provide the first evidence that oxytocin is involved in the regulation of human face processing in dogs. The present study is one of the few empirical investigations that explore eye gaze patterns in naïve and untrained pet dogs using a non-invasive eye-tracking technique and thus offers unique but largely untapped method for studying social cognition in dogs.

  11. Towards Quantum Experiments with Human Eyes as Detectors Based on Cloning via Stimulated Emission

    Science.gov (United States)

    Sekatski, Pavel; Brunner, Nicolas; Branciard, Cyril; Gisin, Nicolas; Simon, Christoph

    2009-09-01

    We show theoretically that a large Bell inequality violation can be obtained with human eyes as detectors, in a “micro-macro” experiment where one photon from an entangled pair is greatly amplified via stimulated emission. The violation is robust under photon loss. This leads to an apparent paradox, which we resolve by noting that the violation proves the existence of entanglement before the amplification. The same is true for the micro-macro experiments performed so far with conventional detectors. However, we also prove that there is genuine micro-macro entanglement even for high loss.

  12. Human head orientation and eye visibility as indicators of attention for goats (Capra hircus

    Directory of Open Access Journals (Sweden)

    Christian Nawroth

    2017-03-01

    Full Text Available Animals domesticated for working closely with humans (e.g. dogs have been shown to be remarkable in adjusting their behaviour to human attentional stance. However, there is little evidence for this form of information perception in species domesticated for production rather than companionship. We tested domestic ungulates (goats for their ability to differentiate attentional states of humans. In the first experiment, we investigated the effect of body and head orientation of one human experimenter on approach behaviour by goats. Test subjects (N = 24 significantly changed their behaviour when the experimenter turned its back to the subjects, but did not take into account head orientation alone. In the second experiment, goats (N = 24 could choose to approach one of two experimenters, while only one was paying attention to them. Goats preferred to approach humans that oriented their body and head towards the subject, whereas head orientation alone had no effect on choice behaviour. In the third experiment, goats (N = 32 were transferred to a separate test arena and were rewarded for approaching two experimenters providing a food reward during training trials. In subsequent probe test trials, goats had to choose between the two experimenters differing in their attentional states. Like in Experiments 1 and 2, goats did not show a preference for the attentive person when the inattentive person turned her head away from the subject. In this last experiment, goats preferred to approach the attentive person compared to a person who closed their eyes or covered the whole face with a blind. However, goats showed no preference when one person covered only the eyes. Our results show that animals bred for production rather than companionship show differences in their approach and choice behaviour depending on human attentive state. However, our results contrast with previous findings regarding the use of the head orientation to attribute attention and show

  13. Expression of transforming growth factor-β2in vitreous body and adjacent tissues during prenatal development of human eye.

    Science.gov (United States)

    Sukhikh, G T; Panova, I G; Smirnova, Yu A; Milyushina, L A; Firsova, N V; Markitantova, Yu V; Poltavtseva, R A; Zinov'eva, R D

    2010-12-01

    Expression of transforming growth factor-β2 was detected by PCR in the vitreous body, lens, retina, and ciliary-iris complex of human eye at early stages of fetal development. Immunochemical assay of the corresponding protein in eye tissues revealed a correlation between the localization of transforming growth factor-β2 and the development of intraocular hyaloid vascular network, its regression, formation of the vitreous body, and development of definite retinal vessels.

  14. Does the foveal shape influence the image formation in human eyes?

    Science.gov (United States)

    Frey, Katharina; Zimmerling, Beatrice; Scheibe, Patrick; Rauscher, Franziska G.; Reichenbach, Andreas; Francke, Mike; Brunner, Robert

    2017-10-01

    In human eyes, the maximum visual acuity correlates locally with the fovea, a shallow depression in the retina. Previous examinations have been reduced to simple geometrical fovea models derived from postmortem preparations and considering only a few superficial ray propagation aspects. In the current study, an extended and realistic analysis of ray-optical simulations for a comprehensive anatomical realistic eye model for the anterior part and realistic aspherical human foveal topographical profiles deduced from in vivo optical coherence tomography (OCT) are presented, and the refractive index step at the transition from vitreous to retinal tissue is taken into account. The optical effect of a commonly shaped (averaged) and an extraordinarily shaped foveal pit were both compared to the analysis of an assumed pure spherical boundary layer. The influence of the aperture size, wavelength, and incident angle on the spot size and shape, as well as the axial focal and lateral centroid position is investigated, and a lateral displacement of about 2 μm and an axial shift of the best focal position of less than 4 μm are found. These findings indicate only small optical effects that are laterally in the range of inter-receptor distances and axially less than the photoreceptor outer segment dimension.

  15. Importance of non-synonymous OCA2 variants in human eye colour prediction

    DEFF Research Database (Denmark)

    Andersen, Jeppe Dyrberg; Pietroni, Carlotta; Johansen, Peter

    2016-01-01

    Background: The color of the eyes is one of the most prominent phenotypes in humans and it is often used to describe the appearance of an individual. The intensity of pigmentation in the iris is strongly associated with one single-nucleotide polymorphism (SNP), rs12913832:A>G that is located in t......) and rs121918166:G>A (p.Val443Ile) had a measurable effect on quantitative skin color (P = 0.008). Conclusion: Our data showed that rs74653330:A>T (p.Ala481Thr) and rs121918166:G>A (p.Val443Ile) have a measurable effect on normal pigmentation variation.......Background: The color of the eyes is one of the most prominent phenotypes in humans and it is often used to describe the appearance of an individual. The intensity of pigmentation in the iris is strongly associated with one single-nucleotide polymorphism (SNP), rs12913832:A>G that is located...

  16. Digital image database processing to simulate image formation in ideal lighting conditions of the human eye

    Science.gov (United States)

    Castañeda-Santos, Jessica; Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Hernández-Méndez, Arturo

    2015-09-01

    The pupil size of the human eye has a large effect in the image quality due to inherent aberrations. Several studies have been performed to calculate its size relative to the luminance as well as considering other factors, i.e., age, size of the adapting field and mono and binocular vision. Moreover, ideal lighting conditions are known, but software suited to our specific requirements, low cost and low computational consumption, in order to simulate radiation adaptation and image formation in the retina with ideal lighting conditions has not yet been developed. In this work, a database is created consisting of 70 photographs corresponding to the same scene with a fixed target at different times of the day. By using this database, characteristics of the photographs are obtained by measuring the luminance average initial threshold value of each photograph by means of an image histogram. Also, we present the implementation of a digital filter for both, image processing on the threshold values of our database and generating output images with the threshold values reported for the human eye in ideal cases. Some potential applications for this kind of filters may be used in artificial vision systems.

  17. Application of Fourier Domain OCT Imaging Technology to the Anterior Segment of the Human Eye

    Science.gov (United States)

    Wojtkowski, Maciej; Marcos, Susana; Ortiz, Sergio; Grulkowski, Ireneusz

    The anterior segment is the front part of the human eye, which forms the optical system and hence directly impacts vision. Traumatic or pathological changes in the anterior segment may lead to vision loss and, in some cases, even blindness. Since the eighteenth century, optical instrumentation for measuring and imaging the anterior segment of the human eye has been developing along with modern ophthalmology. The application of OCT to the anterior segment imaging is particularly of interest, since this could potentially provide substantial complementary information regarding the large-scale architecture of the cornea and the crystalline lens, or on small portions of tissue imaged with high spatial resolutions comparable to regular microscopy. Especially an introduction of Fourier domain detection in OCT has opened new frontiers in OCT ophthalmic applications. The resultant substantial speed improvement enables rapid image acquisition, helping to reduce artifacts due to patient motion. Thus, it is currently possible to perform high-speed, in vivo, three-dimensional volumetric imaging over large scales within a reasonable time limit and without reducing system sensitivity. This chapter describes the state-of the art OCT technology dedicated to anterior segment imaging and indicates all important parameters which are required for optimization of the performance of OCT instrument.

  18. C-reactive protein and complement factor H in aged human eyes and eyes with age-related macular degeneration (AMD)

    Science.gov (United States)

    Bhutto, Imran A; Baba, Takayuki; Merges, Carol; Juriasinghani, Vikash; McLeod, D Scott; Lutty, Gerard A

    2016-01-01

    Background There is increasing evidence that inflammation and immune-mediated processes (complement activation) play an important role in age-related macular degeneration (AMD) pathogenesis. A genetic variation in the complement factor H (CFH) gene and plasma levels of C-reactive protein (CRP), a systemic marker of subclinical inflammation, have been consistently shown to be associated with an increased risk for AMD. In the present study, we examined the immunolocalization of CRP and CFH in aged control human donor eyes (n=10; mean age 79 yrs) and eyes with AMD (n=18; mean age 83 yrs). Methods Alkaline phosphatase immunohistochemistry was performed using polyclonal antibodies against CRP and CFH on cryopreserved tissue sections from disc/macular blocks. Three independent masked observers scored the reaction product (0-8). Results In aged control eyes, the retinal pigment epithelium/Bruch’s membrane/choriocapillaris (RPE/BrM/CC) complex including intercapillary septa (ICS) had the most prominent immunostaining for CRP and CFH. CRP was significantly higher than controls in BrM/CC/ICS and choroidal stroma in early and wet AMD eyes (p<0.05). In contrast, CFH was significantly lower in BrM/CC/ICS complex of AMD choroids than in controls (p<0.05). Interestingly, CRP and CFH were significantly reduced in BrM/CC/ICS complex in atrophic area of macula in geographic atrophy (GA)(p<0.05). Drusen and basal laminar deposits were intensely positive for CRP and CFH. Conclusion These immunohistochemical findings show that changes in distribution and relative levels of CRP and CFH were evident in early and late AMD eyes. This suggests that high levels of CRP and insufficient CFH at the retina/choroid interface may lead to uncontrolled complement activation with associated cell and tissue damage. This study supports the hypothesis that inflammation and immune-mediated mechanisms are involved in the pathogenesis of AMD. PMID:21633121

  19. Measuring higher order optical aberrations of the human eye: techniques and applications

    Directory of Open Access Journals (Sweden)

    L. Alberto V. Carvalho

    2002-11-01

    Full Text Available In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia and higher order aberrations (coma, spherical aberration, etc.. We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45º and 90º. We used a device known as the Hartmann-Shack (HS sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE of less than 0.1 µm for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5º for the axis. This precision is sufficient for customized corneal ablations, among other applications.

  20. EyePhy: Detecting Dependencies in Cyber-Physical System Apps due to Human-in-the-Loop

    Directory of Open Access Journals (Sweden)

    Sirajum Munir

    2015-07-01

    Full Text Available As app based paradigms are becoming popular, millions of apps are developed from many domains including energy, health, security, and entertainment. The US FDA expects that there will be 500 million smart phone users downloading healthcare related apps by 2015. Many of these apps are Cyber-Physical System (CPS apps. In addition to sensing, communication, and computation, they perform interventions to control human physiological parameters, which can cause dependency problems as multiple interventions of multiple apps can increase or decrease each others effects, some of which can be harmful to the user. Such dependency problems occur mainly because each app is unaware about how other apps work and when an app performs an intervention to control its target parameters, it may affect other physiological parameters without even knowing it. We present EyePhy, a system that detects dependencies across interventions by having a closer eye on the physiological parameters of the human in the loop. To do that, EyePhy uses a physiological simulator HumMod that can model the complex interactions of the human physiology using over 7800 variables. EyePhy reduces app developers’ efforts in specifying dependency metadata compared to state of the art solutions and offers personalized dependency analysis for the user. We demonstrate the magnitude of dependencies that arise during multiple interventions in a human body and the significant ability of detecting these dependencies using EyePhy.

  1. Absorption of 308-nm excimer laser radiation by balanced salt solution, sodium hyaluronate, and human cadaver eyes

    Energy Technology Data Exchange (ETDEWEB)

    Keates, R.H.; Bloom, R.T.; Schneider, R.T.; Ren, Q.; Sohl, J.; Viscardi, J.J. (Univ. of California, Irvine (USA))

    1990-11-01

    Absorption of the excimer laser radiations of 193-nm argon fluorine and 308-nm xenon chloride in balanced salt solution, sodium hyaluronate, and human cadaver eyes was measured. The absorption of these materials as considerably different for the two wavelengths; we found that 308-nm light experienced much less absorption than the 193-nm light. The extinction coefficient (k) for 308 nm was k = 0.19/cm for balanced salt solution and k = 0.22/cm for sodium hyaluronate. In contrast to this, the extinction coefficient for 193 nm was k = 140/cm for balanced salt solution and k = 540/cm for sodium hyaluronate. Two 1-day-old human phakic cadaver eyes showed complete absorption with both wavelengths. Using aphakic eyes, incomplete absorption was noted at the posterior pole with 308 nm and complete absorption was noted with 193 nm. The extinction in the anterior part of aphakic eyes (the first 6 mm) was 4.2/cm for 308 nm, meaning that the intensity of the light is reduced by a factor of 10 after traveling the first 5.5 mm. However, we observed that the material in the eye fluoresces, meaning the 308 nm is transformed into other (longer) wavelengths that travel through the total eye with minimal absorption. Conclusions drawn from this experiment are that the use of the 308-nm wavelength may have undesirable side effects, while the use of the 193-nm wavelength should be consistent with ophthalmic use on both the cornea and the lens.

  2. FDTD Computation of Human Eye Exposure to Ultra-wideband Electromagnetic Pulses

    CERN Document Server

    Simicevic, Neven

    2007-01-01

    With an increase in the application of ultra-wideband (UWB) electromagnetic pulses in the communications industry, radar, biotechnology and medicine, comes an interest in UWB exposure safety standards. Despite an increase of the scientific research on bioeffects of exposure to non-ionizing UWB pulses, characterization of those effects is far from complete. A numerical computational approach, such as a finite-difference time domain (FDTD) method, is required to visualize and understand the complexity of broadband electromagnetic interactions. The FDTD method has almost no limits in the description of the geometrical and dispersive properties of the simulated material, it is numerically robust and appropriate for current computer technology. In this paper, a complete calculation of exposure of the human eye to UWB electromagnetic pulses in the frequency range of 3.1-10.6, 22-29, and 57-64 GHz is performed. Computation in this frequency range required a geometrical resolution of the eye of $\\rm 0.1 \\: mm$ and an...

  3. Simple, Inexpensive Technique for High-Quality Smartphone Fundus Photography in Human and Animal Eyes

    Directory of Open Access Journals (Sweden)

    Luis J. Haddock

    2013-01-01

    Full Text Available Purpose. We describe in detail a relatively simple technique of fundus photography in human and rabbit eyes using a smartphone, an inexpensive app for the smartphone, and instruments that are readily available in an ophthalmic practice. Methods. Fundus images were captured with a smartphone and a 20D lens with or without a Koeppe lens. By using the coaxial light source of the phone, this system works as an indirect ophthalmoscope that creates a digital image of the fundus. The application whose software allows for independent control of focus, exposure, and light intensity during video filming was used. With this app, we recorded high-definition videos of the fundus and subsequently extracted high-quality, still images from the video clip. Results. The described technique of smartphone fundus photography was able to capture excellent high-quality fundus images in both children under anesthesia and in awake adults. Excellent images were acquired with the 20D lens alone in the clinic, and the addition of the Koeppe lens in the operating room resulted in the best quality images. Successful photodocumentation of rabbit fundus was achieved in control and experimental eyes. Conclusion. The currently described system was able to take consistently high-quality fundus photographs in patients and in animals using readily available instruments that are portable with simple power sources. It is relatively simple to master, is relatively inexpensive, and can take advantage of the expanding mobile-telephone networks for telemedicine.

  4. Ion therapy for uveal melanoma in new human eye phantom based on GEANT4 toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Mahdipour, Seyed Ali [Physics Department, Hakim Sabzevari University, Sabzevar (Iran, Islamic Republic of); Mowlavi, Ali Asghar, E-mail: amowlavi@hsu.ac.ir [Physics Department, Hakim Sabzevari University, Sabzevar (Iran, Islamic Republic of); ICTP, Associate Federation Scheme, Medical Physics Field, Trieste (Italy)

    2016-07-01

    Radiotherapy with ion beams like proton and carbon has been used for treatment of eye uveal melanoma for many years. In this research, we have developed a new phantom of human eye for Monte Carlo simulation of tumors treatment to use in GEANT4 toolkit. Total depth−dose profiles for the proton, alpha, and carbon incident beams with the same ranges have been calculated in the phantom. Moreover, the deposited energy of the secondary particles for each of the primary beams is calculated. The dose curves are compared for 47.8 MeV proton, 190.1 MeV alpha, and 1060 MeV carbon ions that have the same range in the target region reaching to the center of tumor. The passively scattered spread-out Bragg peak (SOBP) for each incident beam as well as the flux curves of the secondary particles including neutron, gamma, and positron has been calculated and compared for the primary beams. The high sharpness of carbon beam's Bragg peak with low lateral broadening is the benefit of this beam in hadrontherapy but it has disadvantages of dose leakage in the tail after its Bragg peak and high intensity of neutron production. However, proton beam, which has a good conformation with tumor shape owing to the beam broadening caused by scattering, can be a good choice for the large-size tumors.

  5. Human saccadic eye movements and tracking by active foveation in log polar space

    Science.gov (United States)

    Lim, Fee-Lee; Venkatesh, Svetha; West, Geoffrey A. W.

    1996-04-01

    One of the possible models of the human visual system (HVS) in the computer vision literature has a high resolution fovea and exponentially decreasing resolution periphery. The high resolution fovea is used to extract necessary information in order to solve a vision task and the periphery may be used to detect motion. To obtain the desired information, the fovea is guided by the contents of the scene and other knowledge to position the fovea over areas of interest. These eye movements are called saccades and corrective saccades. A two stage process has been implemented as a mechanism for changing foveation in log polar space. Initially, the open loop stage roughly foveates on the best interest feature and then the closed loop stage is invoked to accurately iteratively converge onto the foveation point. The open loop stage developed for the foveation algorithm is applied to saccadic eye movements and a tracking system. Log polar space is preferred over Cartesian space as: (1) it simultaneously provides high resolution and a wide viewing angle; and (2) feature invariance occurs in the fovea which simplifies the foveation process.

  6. Characterization of human retinal vessel arborisation in normal and amblyopic eyes using multifractal analysis

    Directory of Open Access Journals (Sweden)

    Stefan Tălu

    2015-10-01

    Full Text Available AIM:To characterize the human retinal vessel arborisation in normal and amblyopic eyes using multifractal geometry and lacunarity parameters.METHODS:Multifractal analysis using a box counting algorithm was carried out for a set of 12 segmented and skeletonized human retinal images, corresponding to both normal (6 images and amblyopia states of the retina (6 images.RESULTS:It was found that the microvascular geometry of the human retina network represents geometrical multifractals, characterized through subsets of regions having different scaling properties that are not evident in the fractal analysis. Multifractal analysis of the amblyopia images (segmented and skeletonized versions show a higher average of the generalized dimensions (Dq for q=0, 1, 2 indicating a higher degree of the tree-dimensional complexity associated with the human retinal microvasculature network whereas images of healthy subjects show a lower value of generalized dimensions indicating normal complexity of biostructure. On the other hand, the lacunarity analysis of the amblyopia images (segmented and skeletonized versions show a lower average of the lacunarity parameter Λ than the corresponding values for normal images (segmented and skeletonized versions.CONCLUSION:The multifractal and lacunarity analysis may be used as a non-invasive predictive complementary tool to distinguish amblyopic subjects from healthy subjects and hence this technique could be used for an early diagnosis of patients with amblyopia.

  7. Establishment of human retinal mitoscriptome gene expression signature for diabetic retinopathy using cadaver eyes.

    Science.gov (United States)

    Govindarajan, Gowthaman; Mathews, Saumi; Srinivasan, Karthik; Ramasamy, Kim; Periasamy, Sundaresan

    2017-09-01

    Diabetic retinopathy (DR) is a leading cause of blindness due to retinal microvasculature. We used microarray analysis for the first time to establish the retinal mitoscriptome gene expression signature for DR using human cadaver eyes. Among the 1042 genes, 60 (52-down, 8-up) and 39 (36-down, 3-up) genes were differentially expressed in the DR as compared to normal control and diabetic retinas respectively. These genes were mainly responsible for regulating angiogenesis, anti-oxidant defense mechanism, ATP production and apoptosis contributing to the disease pathology of DR. These findings might be useful for the discovery of biomarker and developing therapeutic regimen. Copyright © 2017 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

  8. An exploratory study on the driving method of speech synthesis based on the human eye reading imaging data

    Science.gov (United States)

    Gao, Pei-pei; Liu, Feng

    2016-10-01

    With the development of information technology and artificial intelligence, speech synthesis plays a significant role in the fields of Human-Computer Interaction Techniques. However, the main problem of current speech synthesis techniques is lacking of naturalness and expressiveness so that it is not yet close to the standard of natural language. Another problem is that the human-computer interaction based on the speech synthesis is too monotonous to realize mechanism of user subjective drive. This thesis introduces the historical development of speech synthesis and summarizes the general process of this technique. It is pointed out that prosody generation module is an important part in the process of speech synthesis. On the basis of further research, using eye activity rules when reading to control and drive prosody generation was introduced as a new human-computer interaction method to enrich the synthetic form. In this article, the present situation of speech synthesis technology is reviewed in detail. Based on the premise of eye gaze data extraction, using eye movement signal in real-time driving, a speech synthesis method which can express the real speech rhythm of the speaker is proposed. That is, when reader is watching corpora with its eyes in silent reading, capture the reading information such as the eye gaze duration per prosodic unit, and establish a hierarchical prosodic pattern of duration model to determine the duration parameters of synthesized speech. At last, after the analysis, the feasibility of the above method is verified.

  9. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life.

    Directory of Open Access Journals (Sweden)

    Niels Lynnerup

    Full Text Available BACKGROUND: Lens crystallines are special proteins in the eye lens. Because the epithelial basement membrane (lens capsule completely encloses the lens, desquamation of aging cells is impossible, and due to the complete absence of blood vessels or transport of metabolites in this area, there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its (14C content from the atmospheric carbon dioxide. The (14C content of the lens proteins thus reflects the atmospheric content of (14C when the lens crystallines were formed. Precise radiocarbon dating is made possible by comparing the (14C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric (14C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close relationship may be further expressed as a mathematical model, which takes into account the timing of the crystalline formation. CONCLUSIONS/SIGNIFICANCE: Such a life-long permanence of human tissue has hitherto only been described for dental enamel. In confront to dental enamel it must be held in mind that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14C content of various tissues may be used to assess turnover rates and degree of substitution (for example for brain cell DNA. Potential targets may be nervous tissues in terms of senile or pre

  10. A new measurement method for color discrimination thresholds of human eyes based on PWM light-mixing technology

    Science.gov (United States)

    Zhang, Jiyan; Dong, Jinxin

    2016-09-01

    The color discrimination is a powerful tool for detection of eye diseases, and it is is necessary to produce different kinds of color rapidly and precisely for testing color discrimination thresholds of human eyes. Three channels' pulse-width modulation (PWM) and light-mixing technology is a new way to mixing color, and a new measurement method for color discrimination thresholds of human eyes based on PWM light-mix technology can generate kinds of color stimuli. In this study, 5 youth volunteers were measured via this equipment after the test for the stability of the device's illumination and chrominance. Though the theory of Macadam ellipses and the interleaved staircase method, a psychophysical experiment was made to study the color discrimination threshold of the human eyes around a basic color center. By analyzing the data of the chromatic ellipse and the color discrimination threshold, the result shows that each color is not uniform in a single color region and the color difference threshold of normal human is around the third Macadam ellipses. The experimental results show that the repeatability and accuracy of the observer can meet the accuracy requirements of the relevant experiments, and the data is reliable and effective, which means the measurement method is an effective way to measure the color discrimination thresholds of human visual system.

  11. The effects of radiant cooling versus convective cooling on human eye tear film stability and blinking rate

    DEFF Research Database (Denmark)

    Nygaard, Linette; Uth, Simon C.; Bolashikov, Zhecho Dimitrov

    2014-01-01

    The effect of indoor temperature, radiant and convective cooling on tear film stability and eye blink frequency was examined. 24 human subjects were exposed to the non-uniform environment generated by localised chilled beam and a chilled ceiling combined with overhead mixing ventilation. The subj......The effect of indoor temperature, radiant and convective cooling on tear film stability and eye blink frequency was examined. 24 human subjects were exposed to the non-uniform environment generated by localised chilled beam and a chilled ceiling combined with overhead mixing ventilation....... The subjects participated in four two-hour experiments. The room air temperature was kept at 26 °C or 28 °C. Tear film samples were collected after 30 min of acclimatisation and at the end of the exposures. Eye blinking frequency was analysed for the first and last 15 min of each exposure. The tear film...

  12. Towards free 3D end-point control for robotic-assisted human reaching using binocular eye tracking.

    Science.gov (United States)

    Maimon-Dror, Roni O; Fernandez-Quesada, Jorge; Zito, Giuseppe A; Konnaris, Charalambos; Dziemian, Sabine; Faisal, A Aldo

    2017-07-01

    Eye-movements are the only directly observable behavioural signals that are highly correlated with actions at the task level, and proactive of body movements and thus reflect action intentions. Moreover, eye movements are preserved in many movement disorders leading to paralysis (or amputees) from stroke, spinal cord injury, Parkinson's disease, multiple sclerosis, and muscular dystrophy among others. Despite this benefit, eye tracking is not widely used as control interface for robotic interfaces in movement impaired patients due to poor human-robot interfaces. We demonstrate here how combining 3D gaze tracking using our GT3D binocular eye tracker with custom designed 3D head tracking system and calibration method enables continuous 3D end-point control of a robotic arm support system. The users can move their own hand to any location of the workspace by simple looking at the target and winking once. This purely eye tracking based system enables the end-user to retain free head movement and yet achieves high spatial end point accuracy in the order of 6 cm RMSE error in each dimension and standard deviation of 4 cm. 3D calibration is achieved by moving the robot along a 3 dimensional space filling Peano curve while the user is tracking it with their eyes. This results in a fully automated calibration procedure that yields several thousand calibration points versus standard approaches using a dozen points, resulting in beyond state-of-the-art 3D accuracy and precision.

  13. Analysis and comparison of proteomic profiles of tear fluid from human, cow, sheep, and camel eyes.

    Science.gov (United States)

    Shamsi, Farrukh A; Chen, Ziyan; Liang, Jingwen; Li, Kaijun; Al-Rajhi, Ali A; Chaudhry, Imtiaz A; Li, Mingtao; Wu, Kaili

    2011-11-25

    To investigate the tear proteome profiles of human, cow, sheep, and camel comparatively and to explore the difference of tear protein profiles among different species. Tears were collected from both eyes of 25 clinically healthy volunteers, 50 cows, 25 sheep, and 50 camels. Pooled tear protein samples were separated by SDS-PAGE and two-dimensional electrophoresis. Protein spots of differential expression were excised and subjected to in-gel digestion and identification by matrix assisted laser desorption/ionization-time-of-flight/time-of-flight mass spectrum analysis. Because of the incomplete genomic data of cow, sheep, and camel, a combined strategy of de novo sequencing and BLAST (Best Local Alignment Search Tool) homology searching was also used for protein identification. The differentially expressed proteins were validated by Western blot analysis. On comparison with human tears (182 ± 6 spots), 223 ± 8, 217 ± 11, and 241 ± 3 well-resolved protein spots were detected in triphenylmethane dye-stained gels of cow, sheep, and camel tears, respectively. Similar high-abundant proteins (lactoferrin, lysozyme, etc.) were found in all tear fluids. Tear lipocalins have been identified in cow and sheep tears. BLAST searching revealed a 21-kDa protein, identical with human vitelline membrane outer layer protein 1 (VMO1) homolog, in camel tears. The Western blot confirmed that VMO1 homolog was present in both camel and sheep tears but not in human and cow tears. The comparative proteomic analyses of tears from healthy humans, cows, sheep, and camels were first reported. Differential protein expression existed in the tear among species, offering useful information for further study on tear proteins and the related ocular diseases.

  14. Delineation of motoneuron subgroups supplying individual eye muscles in the human oculomotor nucleus.

    Science.gov (United States)

    Che Ngwa, Emmanuel; Zeeh, Christina; Messoudi, Ahmed; Büttner-Ennever, Jean A; Horn, Anja K E

    2014-01-01

    The oculomotor nucleus (nIII) contains the motoneurons of medial, inferior, and superior recti (MR, IR, and SR), inferior oblique (IO), and levator palpebrae (LP) muscles. The delineation of motoneuron subgroups for each muscle is well-known in monkey, but not in human. We studied the transmitter inputs to human nIII and the trochlear nucleus (nIV), which innervates the superior oblique muscle (SO), to outline individual motoneuron subgroups. Parallel series of sections from human brainstems were immunostained for different markers: choline acetyltransferase combined with glutamate decarboxylase (GAD), calretinin (CR) or glycine receptor. The cytoarchitecture was visualized with cresyl violet, Gallyas staining and expression of non-phosphorylated neurofilaments. Apart from nIV, seven subgroups were delineated in nIII: the central caudal nucleus (CCN), a dorsolateral (DL), dorsomedial (DM), central (CEN), and ventral (VEN) group, the nucleus of Perlia (NP) and the non-preganglionic centrally projecting Edinger-Westphal nucleus (EWcp). DL, VEN, NP, and EWcp were characterized by a strong supply of GAD-positive terminals, in contrast to DM, CEN, and nIV. CR-positive terminals and fibers were confined to CCN, CEN, and NP. Based on location and histochemistry of the motoneuron subgroups in monkey, CEN is considered as the SR and IO motoneurons, DL and VEN as the B- and A-group of MR motoneurons, respectively, and DM as IR motoneurons. A good correlation between monkey and man is seen for the CR input, which labels only motoneurons of eye muscles participating in upgaze (SR, IO, and LP). The CCN contained LP motoneurons, and nIV those of SO. This study provides a map of the individual subgroups of motoneurons in human nIII for the first time, and suggests that NP may contain upgaze motoneurons. Surprisingly, a strong GABAergic input to human MR motoneurons was discovered, which is not seen in monkey and may indicate a functional oculomotor specialization.

  15. Joint attention without gaze following: human infants and their parents coordinate visual attention to objects through eye-hand coordination.

    Directory of Open Access Journals (Sweden)

    Chen Yu

    Full Text Available The coordination of visual attention among social partners is central to many components of human behavior and human development. Previous research has focused on one pathway to the coordination of looking behavior by social partners, gaze following. The extant evidence shows that even very young infants follow the direction of another's gaze but they do so only in highly constrained spatial contexts because gaze direction is not a spatially precise cue as to the visual target and not easily used in spatially complex social interactions. Our findings, derived from the moment-to-moment tracking of eye gaze of one-year-olds and their parents as they actively played with toys, provide evidence for an alternative pathway, through the coordination of hands and eyes in goal-directed action. In goal-directed actions, the hands and eyes of the actor are tightly coordinated both temporally and spatially, and thus, in contexts including manual engagement with objects, hand movements and eye movements provide redundant information about where the eyes are looking. Our findings show that one-year-olds rarely look to the parent's face and eyes in these contexts but rather infants and parents coordinate looking behavior without gaze following by attending to objects held by the self or the social partner. This pathway, through eye-hand coupling, leads to coordinated joint switches in visual attention and to an overall high rate of looking at the same object at the same time, and may be the dominant pathway through which physically active toddlers align their looking behavior with a social partner.

  16. Simultaneous recordings of human microsaccades and drifts with a contemporary video eye tracker and the search coil technique.

    Directory of Open Access Journals (Sweden)

    Michael B McCamy

    Full Text Available Human eyes move continuously, even during visual fixation. These "fixational eye movements" (FEMs include microsaccades, intersaccadic drift and oculomotor tremor. Research in human FEMs has grown considerably in the last decade, facilitated by the manufacture of noninvasive, high-resolution/speed video-oculography eye trackers. Due to the small magnitude of FEMs, obtaining reliable data can be challenging, however, and depends critically on the sensitivity and precision of the eye tracking system. Yet, no study has conducted an in-depth comparison of human FEM recordings obtained with the search coil (considered the gold standard for measuring microsaccades and drift and with contemporary, state-of-the art video trackers. Here we measured human microsaccades and drift simultaneously with the search coil and a popular state-of-the-art video tracker. We found that 95% of microsaccades detected with the search coil were also detected with the video tracker, and 95% of microsaccades detected with video tracking were also detected with the search coil, indicating substantial agreement between the two systems. Peak/mean velocities and main sequence slopes of microsaccades detected with video tracking were significantly higher than those of the same microsaccades detected with the search coil, however. Ocular drift was significantly correlated between the two systems, but drift speeds were higher with video tracking than with the search coil. Overall, our combined results suggest that contemporary video tracking now approaches the search coil for measuring FEMs.

  17. An Interactive Method for Teaching Anatomy of the Human Eye for Medical Students in Ophthalmology Clinical Rotations

    Science.gov (United States)

    Kivell, Tracy L.; Doyle, Sara K.; Madden, Richard H.; Mitchell, Terry L.; Sims, Ershela L.

    2009-01-01

    Much research has shown the benefits of additional anatomical learning and dissection beyond the first year of medical school human gross anatomy, all the way through postgraduate medical training. We have developed an interactive method for teaching eye and orbit anatomy to medical students in their ophthalmology rotation at Duke University…

  18. Collaborative EDNAP exercise on the IrisPlex system for DNA-based prediction of human eye colour

    NARCIS (Netherlands)

    L.C. Chaitanya (Lakshmi); S. Walsh (Susan); J.D. Andersen (Jeppe Dyrberg); R. Ansell (Ricky); K. Ballantyne (Kaye); D.J. Ballard (David); R. Banemann (Regine); C.M. Bauer (Christiane Maria); A.M. Bento (Ana Margarida); F. Brisighelli (Francesca); T. Capal (Tomas); L. Clarisse (Lindy); T.E. Gross (Theresa); C. Haas (Cordula); P. Hoff-Olsen (Per); C. Hollard (Clémence); C. Keyser (Christine); K.M. Kiesler (Kevin); P. Kohler (Priscila); T. Kupiec (Tomasz); A. Linacre (Adrian); A. Minawi (Anglika); N. Morling (Niels); H. Nilsson (Helena); L. Norén (Lina); R. Ottens (Renée); J. Palo (Jukka); W. Parson (Walther); V.L. Pascali (Vincenzo); C. Phillips (Christopher); M.J. Porto (Maria João); A. Sajantila (Antti); P.M. Schneider (Peter); T. Sijen (Titia); J. Söchtig (Jens); D. Syndercombe-Court (Denise); A. Tillmar (Andreas); M. Turanska (Martina); P.M. Vallone (Peter); L. Zatkalíková (Lívia); A. Zidkova (Anastassiya); W. Branicki (Wojciech); M.H. Kayser (Manfred)

    2014-01-01

    textabstractThe IrisPlex system is a DNA-based test system for the prediction of human eye colour from biological samples and consists of a single forensically validated multiplex genotyping assay together with a statistical prediction model that is based on genotypes and phenotypes from thousands

  19. Oxygen Tension in the Aqueous Humor of Human Eyes under Different Oxygenation Conditions

    Directory of Open Access Journals (Sweden)

    Farideh Sharifipour

    2013-01-01

    Full Text Available Purpose: To measure oxygen tension in the aqueous humor of human eyes under different oxygenation conditions. Methods: This prospective comparative interventional case series consisted of two parts. In the first part, 120 consecutive patients scheduled for cataract surgery were randomized into group I (control group in which surgery was performed under local anesthesia inhaling 21% oxygen; group II in whom general anesthesia using 50% oxygen was employed; and group III receiving general anesthesia with 100% oxygen. After aspirating 0.2 ml aqueous humor under sterile conditions, the aqueous sample and a simultaneously drawn arterial blood sample were immediately analyzed using a blood gas analyzer. In part II the same procedures were performed in 10 patients after fitting a contact lens and patching the eye for 20 minutes (group IV and in 10 patients after transcorneal delivery of oxygen at a flow rate of 5 L/min (group V. Results: Mean aqueous PO2 in groups I, II and III was 112.3±6.2, 141.1±20.4, and 170.1±27 mmHg, respectively (P values <0.001 and mean arterial PO2 was 85.7±7.9, 184.6±46, and 379.1±75.9 mmHg, respectively (P values <0.001. Aqueous PO2 was 77.2±9.2 mmHg in group IV and 152.3±10.9 mmHg in group V (P values <0.001. There was a significant correlation between aqueous and blood PO2 (r=0.537, P<0.001. The contribution of atmospheric oxygen to aqueous PO2 was 23.7%. Conclusion: Aqueous oxygen tension is mostly dependent on the systemic circulation and in part on the atmosphere. Increasing inspiratory oxygen and transcorneal oxygen delivery both increase aqueous PO2 levels.

  20. Development of the hyaloid, choroidal and retinal vasculatures in the fetal human eye.

    Science.gov (United States)

    Lutty, Gerard A; McLeod, D Scott

    2017-11-01

    The development of the ocular vasculatures is perfectly synchronized to provide the nutritional and oxygen requirements of the forming human eye. The fetal vasculature of vitreous, which includes the hyaloid vasculature, vasa hyaloidea propria, and tunica vasculosa lentis, initially develops around 4-6 weeks gestation (WG) by hemo-vasculogenesis (development of blood and blood vessels from a common progenitor, the hemangioblast). This transient fetal vasculature expands around 12 WG by angiogenesis (budding from primordial vessels) and remains until a retinal vasculature begins to form. The fetal vasculature then regresses by apoptosis with the assistance of macrophages/hyalocytes. The human choroidal vasculature also forms by a similar process and will supply nutrients and oxygen to outer retina. This lobular vasculature develops in a dense collagenous tissue juxtaposed with a cell constitutively producing vascular endothelial growth factor (VEGF), the retinal pigment epithelium. This epithelial/endothelial relationship is critical in maintaining the function of this vasculature throughout life and maintaining it's fenestrated state. The lobular capillary system (choriocapillaris) develops first by hemo-vasculogenesis and then the intermediate choroidal blood vessels form by angiogenesis, budding from the choriocapillaris. The human retinal vasculature is the last to develop. It develops by vasculogenesis, assembly of CXCR4(+)/CD39(+) angioblasts or vascular progenitors perhaps using Muller cell Notch1 or axonal neuropilinin-1 for guidance of semaphorin 3A-expressing angioblasts. The fovea never develops a retinal vasculature, which is probably due to the foveal avascular zone area of retina expressing high levels of antiangiogenic factors. From these studies, it is apparent that development of the mouse ocular vasculatures is not representative of the development of the human fetal, choroidal and retinal vasculatures. Copyright © 2017 Elsevier Ltd. All rights

  1. Metallothioneins (MTs) in the human eye: a perspective article on the zinc-MT redox cycle.

    Science.gov (United States)

    Gonzalez-Iglesias, Héctor; Alvarez, Lydia; García, Montserrat; Petrash, Carson; Sanz-Medel, Alfredo; Coca-Prados, Miguel

    2014-02-01

    Metallothioneins (MTs) are zinc-ion-binding proteins with a wide range of functions, among which are neuroprotection, maintenance of cellular zinc homeostasis, and defense against oxidative damage and inflammation. The human eye is enriched in MTs, and multiple isoforms may contribute to distinct antioxidant defense mechanisms in various ocular tissues. Zinc is a main regulator of MT gene and protein expression, and we recently applied bioanalytical techniques to address key questions on its relationship with MTs, including the stoichiometry of zinc-MT, the fate of zinc tracers ((nat)Zn and (68)Zn) in MTs during activation by exogenous zinc and cytokines, and the concentration of MTs in human ocular cells. We found that exogenously introduced zinc induced a potent de novo synthesis of MTs as well as a strong inhibition of pro-inflammatory cytokines. Zinc and cytokines also promote a stoichiometric transition of the MT complex from Zn6Cu1-MT to Zn7-MT, suggesting that MTs may interact more effectively with reactive oxygen species to decrease potential oxidative damage. Levels of MTs decrease with aging and disease, which may result in zinc release that is potentially cytotoxic. This state is also observed with increased oxidative stress and inflammation, suggesting that the antioxidant function of MTs has been impaired. In this review we propose a working model of the "zinc-metallothionein redox cycle" to regenerate and enhance the antioxidant function of MTs with the aim of combating the progression of these disease states.

  2. A novel device for head gesture measurement system in combination with eye-controlled human machine interface

    Science.gov (United States)

    Lin, Chern-Sheng; Ho, Chien-Wa; Chang, Kai-Chieh; Hung, San-Shan; Shei, Hung-Jung; Yeh, Mau-Shiun

    2006-06-01

    This study describes the design and combination of an eye-controlled and a head-controlled human-machine interface system. This system is a highly effective human-machine interface, detecting head movement by changing positions and numbers of light sources on the head. When the users utilize the head-mounted display to browse a computer screen, the system will catch the images of the user's eyes with CCD cameras, which can also measure the angle and position of the light sources. In the eye-tracking system, the program in the computer will locate each center point of the pupils in the images, and record the information on moving traces and pupil diameters. In the head gesture measurement system, the user wears a double-source eyeglass frame, so the system catches images of the user's head by using a CCD camera in front of the user. The computer program will locate the center point of the head, transferring it to the screen coordinates, and then the user can control the cursor by head motions. We combine the eye-controlled and head-controlled human-machine interface system for the virtual reality applications.

  3. Lipid-protein interactions in plasma membranes of fiber cells isolated from the human eye lens.

    Science.gov (United States)

    Raguz, Marija; Mainali, Laxman; O'Brien, William J; Subczynski, Witold K

    2014-03-01

    The protein content in human lens membranes is extremely high, increases with age, and is higher in the nucleus as compared with the cortex, which should strongly affect the organization and properties of the lipid bilayer portion of intact membranes. To assess these effects, the intact cortical and nuclear fiber cell plasma membranes isolated from human lenses from 41- to 60-year-old donors were studied using electron paramagnetic resonance spin-labeling methods. Results were compared with those obtained for lens lipid membranes prepared from total lipid extracts from human eyes of the same age group [Mainali, L., Raguz, M., O'Brien, W. J., and Subczynski, W. K. (2013) Biochim. Biophys. Acta]. Differences were considered to be mainly due to the effect of membrane proteins. The lipid-bilayer portions of intact membranes were significantly less fluid than lipid bilayers of lens lipid membranes, prepared without proteins. The intact membranes were found to contain three distinct lipid environments termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain. However, the cholesterol bilayer domain, which was detected in cortical and nuclear lens lipid membranes, was not detected in intact membranes. The relative amounts of bulk and trapped lipids were evaluated. The amount of lipids in domains uniquely formed due to the presence of membrane proteins was greater in nuclear membranes than in cortical membranes. Thus, it is evident that the rigidity of nuclear membranes is greater than that of cortical membranes. Also the permeability coefficients for oxygen measured in domains of nuclear membranes were significantly lower than appropriate coefficients measured in cortical membranes. Relationships between the organization of lipids into lipid domains in fiber cells plasma membranes and the organization of membrane proteins are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Identification of intracellular phospholipases A2 in the human eye: involvement in phagocytosis of photoreceptor outer segments

    DEFF Research Database (Denmark)

    Kolko, Miriam; Wang, Jinmei; Zhan, Chen

    2007-01-01

    , and IVC; and iPLA(2), group VIB, were identified in the human RPE cell line ARPE-19. Furthermore, protein of iPLA(2)-VIA, cPLA(2)-IVA, and iPLA(2)-VIB were identified in ARPE-19 cells and in various parts of the normal human eye. iPLA(2)-VIA protein levels were upregulated during phagocytosis, and iPLA(2......RNA and protein expression of intracellular PLA(2) subtypes in the retinal pigment epithelial cell line ARPE-19. Immunohistochemical staining of normal human eye sections was performed to reveal the cellular location of the enzymes. A model of RPE phagocytosis of POS was used to explore the role of intracellular...

  5. Eye Allergies

    Science.gov (United States)

    ... Stories Español Eye Health / Eye Health A-Z Eye Allergies Sections What Are Eye Allergies? Eye Allergy ... Eye allergy diagnosis Eye allergy treatment What Are Eye Allergies? Leer en Español: ¿Qué Son las Alergias ...

  6. Human sound-localization behaviour after multiple changes in eye position.

    NARCIS (Netherlands)

    Grootel, T.J. van; Opstal, A.J. van

    2009-01-01

    Orienting the eyes towards a peripheral sound source calls for a transformation of the head-centred sound coordinates into an oculocentric motor command, which requires an estimate of current eye position. Current models of saccadic control explain spatial accuracy by oculocentric transformations

  7. Xenopus pax6 mutants affect eye development and other organ systems, and have phenotypic similarities to human aniridia patients.

    Science.gov (United States)

    Nakayama, Takuya; Fisher, Marilyn; Nakajima, Keisuke; Odeleye, Akinleye O; Zimmerman, Keith B; Fish, Margaret B; Yaoita, Yoshio; Chojnowski, Jena L; Lauderdale, James D; Netland, Peter A; Grainger, Robert M

    2015-12-15

    Mutations in the Pax6 gene cause ocular defects in both vertebrate and invertebrate animal species, and the disease aniridia in humans. Despite extensive experimentation on this gene in multiple species, including humans, we still do not understand the earliest effects on development mediated by this gene. This prompted us to develop pax6 mutant lines in Xenopus tropicalis taking advantage of the utility of the Xenopus system for examining early development and in addition to establish a model for studying the human disease aniridia in an accessible lower vertebrate. We have generated mutants in pax6 by using Transcription Activator-Like Effector Nuclease (TALEN) constructs for gene editing in X. tropicalis. Embryos with putative null mutations show severe eye abnormalities and changes in brain development, as assessed by changes in morphology and gene expression. One gene that we found is downregulated very early in development in these pax6 mutants is myc, a gene involved in pluripotency and progenitor cell maintenance and likely a mediator of some key pax6 functions in the embryo. Changes in gene expression in the developing brain and pancreas reflect other important functions of pax6 during development. In mutations with partial loss of pax6 function eye development is initially relatively normal but froglets show an underdeveloped iris, similar to the classic phenotype (aniridia) seen in human patients with PAX6 mutations. Other eye abnormalities observed in these froglets, including cataracts and corneal defects, are also common in human aniridia. The frog model thus allows us to examine the earliest deficits in eye formation as a result of pax6 lesions, and provides a useful model for understanding the developmental basis for the aniridia phenotype seen in humans. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Delineation of motoneuron subgroups supplying individual eye muscles in the human oculomotor nucleus

    Directory of Open Access Journals (Sweden)

    Emmanuel eChe-Ngwa

    2014-02-01

    Full Text Available The oculomotor nucleus (nIII contains the motoneurons of medial, inferior and superior recti (MR, IR, SR, inferior oblique (IO and levator palpebrae (LP muscles. The delineation of motoneuron subgroups for each muscle is well-known in monkey, but not in human. We studied the transmitter inputs to human nIII and the trochlear nucleus (nIV, which innervates the superior oblique muscle (SO, to outline individual motoneuron subgroups. Parallel series of sections from human brainstems were immunostained for different markers: acetylcholine transferase (ChAT combined with glutamate decarboxylase (GAD, calretinin (CR or glycine receptor (GlyR. The cytoarchitecture was visualized with Cresyl violet, Gallyas staining and expression of non-phosphorylated neurofilaments (NP-NF. Apart from nIV, seven subgroups were delineated in nIII: the central caudal nucleus (CCN, a dorsolateral (DL, dorsomedial (DM, central (CEN, and ventral group (VEN, the nucleus of Perlia (NP and the non-preganglionic centrally projecting Edinger-Westphal nucleus (EWcp. DL, VEN, NP and EWcp were characterized by a strong supply of GAD-positive terminals, in contrast to DM, CEN and nIV. CR-positive terminals and fibres were confined to CCN, CEN and NP. Based on location and histochemistry of the motoneuron subgroups in monkey, CEN is considered as the SR and IO motoneurons, DL and VEN as the B- and A-group of MR motoneurons, respectively, and DM as IR motoneurons. A good correlation between monkey and man is seen for the CR input, which labels only motoneurons of eye muscles participating in upgaze (SR, IO and LP. The CCN contained LP motoneurons, and nIV those of SO. This study provides a map of the individual subgroups of motoneurons in human nIII for the first time, and suggests that NP may contain upgaze motoneurons. Surprisingly, a strong GABAergic input to human MR motoneurons was discovered, which is not seen in monkey and may indicate a functional oculomotor specialization.

  9. 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 ...

  10. Surface wave elastometry of the cornea in porcine and human donor eyes.

    Science.gov (United States)

    Dupps, William J; Netto, Marcelo V; Herekar, Satish; Krueger, Ronald R

    2007-01-01

    To introduce a nondestructive technique for characterization of corneal stiffness, determine measurement precision, and investigate comparative stiffness values along central, radial, and circumferential vectors in porcine corneas. The effects of epithelial debridement, relaxing incisions, and crosslink-mediated stiffening on surface wave velocity are also studied. A handheld prototype system was used to measure ultrasound surface wave propagation time between two fixed-distance transducers along a ten-position map. Repeatability was assessed with replicate measurements in 6 porcine corneas. In 12 porcine globes with controlled intraocular pressure (IOP), serial measurements were performed before and after epithelial removal, then after 250- and 750-microm-deep relaxing incisions. In human globes with constant intravitreal pressure, central wave velocity and transcorneal IOP measurements were compared before and after collagen cross-linking. Measurement repeatability across all regions was between 2.2% and 8.1%. Epithelial removal resulted in increases in measured stiffness in 67% of eyes, but statistical power was insufficient to detect a systematic change. Wave velocity across a central incision decreased significantly after 250-microm keratotomy (P biomechanical properties that are relevant in refractive surgery, ectatic disease, and glaucoma.

  11. Surface Wave Elastometry of the Cornea in Porcine and Human Donor Eyes

    Science.gov (United States)

    Dupps, William J.; Netto, Marcelo V.; Herekar, Satish; Krueger, Ronald R.

    2007-01-01

    PURPOSE To introduce a nondestructive technique for characterization of corneal stiffness, determine measurement precision, and investigate comparative stiffness values along central, radial, and circumferential vectors in porcine corneas. The effects of epithelial debridement, relaxing incisions, and crosslink-mediated stiffening on surface wave velocity are also studied. METHODS A handheld prototype system was used to measure ultrasound surface wave propagation time between two fixed-distance transducers along a ten-position map. Repeatability was assessed with replicate measurements in 6 porcine corneas. In 12 porcine globes with controlled intraocular pressure (IOP), serial measurements were performed before and after epithelial removal, then after 250- and 750-μm-deep relaxing incisions. In human globes with constant intravitreal pressure, central wave velocity and transcorneal IOP measurements were compared before and after collagen cross-linking. RESULTS Measurement repeatability across all regions was between 2.2% and 8.1%. Epithelial removal resulted in increases in measured stiffness in 67% of eyes, but statistical power was insufficient to detect a systematic change. Wave velocity across a central incision decreased significantly after 250-μm keratotomy (Pcollagen cross-linking despite maintenance of a constant IOP. CONCLUSIONS Handheld corneal elastometry provides a repeatable measure of regional stiffness changes after relaxing incisions and collagen cross-linking in in vitro experiments. Surface wave elastometry allows focal assessment of corneal biomechanical properties that are relevant in refractive surgery, ectatic disease, and glaucoma. PMID:17269246

  12. Ab interno trabeculectomy: ultrastructural evidence and early tissue response in a human eye.

    Science.gov (United States)

    Ferrari, Ettore; Ortolani, Fulvia; Petrelli, Lucia; Contin, Magali; Pognuz, Derri Roman; Marchini, Maurizio; Bandello, Francesco

    2007-10-01

    To report the results of ultrastructural analysis of the postoperative effects of ab interno trabeculectomy in a human eye. Department of Ophthalmology, Palmanova Hospital, Palmanova, Udine, Italy. A 60-year-old woman with cataract and glaucoma had enucleation for a choroidal melanoma 10 days after ab interno trabeculectomy combined with phacoemulsification. A second ab interno trabeculectomy was performed after enucleation to evaluate the outcomes of the previous trabeculectomy. Light and transmission electron microscopy analyses were performed on samples excised from areas (1) not subjected to a procedure (control samples), (2) that had ab interno trabeculectomy before enucleation, and (3) that had ab interno trabeculectomy immediately after enucleation. Control samples showed normal trabecular features. Semithin sections of all ab interno trabeculectomy samples showed full-thickness removal of trabeculum segments, with Schlemm's canal lumen opening into the anterior chamber and apparent preservation of the adjacent structures. On ultrathin sections of samples that had ab interno trabeculectomy before enucleation, the endothelium lining the outer wall of Schlemm's canal and other angle components showed intact ultrastructural features. In trabecular beams that were not removed, the extracellular matrix appeared to have maintained its fine texture and was free of activated fibroblasts or leucocyte infiltrates. Observations confirm that ab interno trabeculectomy causes direct communication between Schlemm's canal lumen and the anterior chamber in vivo and immediately after enucleation during the early postoperative period. The absence of an evident inflammatory reaction in the examined case should be considered with caution because of possible tumor-induced immune suppression.

  13. Apnea-induced rapid eye movement sleep disruption impairs human spatial navigational memory.

    Science.gov (United States)

    Varga, Andrew W; Kishi, Akifumi; Mantua, Janna; Lim, Jason; Koushyk, Viachaslau; Leibert, David P; Osorio, Ricardo S; Rapoport, David M; Ayappa, Indu

    2014-10-29

    Hippocampal electrophysiology and behavioral evidence support a role for sleep in spatial navigational memory, but the role of particular sleep stages is less clear. Although rodent models suggest the importance of rapid eye movement (REM) sleep in spatial navigational memory, a similar role for REM sleep has never been examined in humans. We recruited subjects with severe obstructive sleep apnea (OSA) who were well treated and adherent with continuous positive airway pressure (CPAP). Restricting CPAP withdrawal to REM through real-time monitoring of the polysomnogram provides a novel way of addressing the role of REM sleep in spatial navigational memory with a physiologically relevant stimulus. Individuals spent two different nights in the laboratory, during which subjects performed timed trials before and after sleep on one of two unique 3D spatial mazes. One night of sleep was normally consolidated with use of therapeutic CPAP throughout, whereas on the other night, CPAP was reduced only in REM sleep, allowing REM OSA to recur. REM disruption via this method caused REM sleep reduction and significantly fragmented any remaining REM sleep without affecting total sleep time, sleep efficiency, or slow-wave sleep. We observed improvements in maze performance after a night of normal sleep that were significantly attenuated after a night of REM disruption without changes in psychomotor vigilance. Furthermore, the improvement in maze completion time significantly positively correlated with the mean REM run duration across both sleep conditions. In conclusion, we demonstrate a novel role for REM sleep in human memory formation and highlight a significant cognitive consequence of OSA. Copyright © 2014 the authors 0270-6474/14/3414571-07$15.00/0.

  14. Human Response to Ductless Personalised Ventilation: Impact of Air Movement, Temperature and Cleanness on Eye Symptoms

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Fillon, Maelys; Bivolarova, Maria

    2013-01-01

    The performance of ductless personalized ventilation (DPV) in conjunction with displacement ventilation (DV) was studied in relation to peoples’ health, comfort and performance. This paper presents results on the impact of room air temperature, using of DPV and local air filtration on eye blink...... environment facially applied individually controlled air movement of room air, with or without local filtering, did not have significant impact on eye blink frequency and tear film quality. The local air movement and air cleaning resulted in increased eye blinking frequency and improvement of tear film...

  15. Eye torsion associated with disparity-induced vertical vergence in humans

    NARCIS (Netherlands)

    L.J. van Rijn (Laurentius); H. Collewijn (Han)

    1994-01-01

    textabstractRecently, Enright described an unexpected association between disparity-induced vertical vergence and cycloversion (conjugate eye torsion) [Enright (1992)Vision Research, 415, 279]. The present experiments were performed to verify these findings and investigate the nature of this

  16. Accommodative Movements of the Vitreous Membrane, Choroid, and Sclera in Young and Presbyopic Human and Nonhuman Primate Eyes

    Science.gov (United States)

    Croft, Mary Ann; Nork, T. Michael; McDonald, Jared P.; Katz, Alexander; Lütjen-Drecoll, Elke; Kaufman, Paul L.

    2013-01-01

    Purpose. We report, for the first time to our knowledge, dynamic movements of the vitreous membrane and peripheral choroid during accommodation, and age-related changes in the anterior sclera. Methods. We studied 11 rhesus monkeys (ages 6–27 years) and 12 human subjects (ages 19–65 years). Accommodation was induced pharmacologically in human subjects and by central electrical stimulation in the monkeys. Ultrasound biomicroscopy, endoscopy, and contrast agents were used to image various intraocular structures. Results. In the monkey, the anterior hyaloid membrane bows backward during accommodation in proportion to accommodative amplitude and lens thickening. A cleft exists between the pars plicata region and the anterior hyaloid membrane, and the cleft width increases during accommodation from 0.79 ± 0.01 mm to 1.01 ± 0.02 mm in young eyes (n = 2, P vitreous zonule, and the neighboring vitreous interconnected with the vitreous zonule. Among the humans, in the older eyes the scleral contour bowed inward in the region of the limbus, compared to the young eyes. Conclusions. The monkey anterior hyaloid bends posteriorly during accommodation in proportion to accommodative amplitude and the sclera bows inward with increasing age in both species. Future descriptions of the accommodative mechanism, and approaches to presbyopia therapy, may need to incorporate these findings. PMID:23745005

  17. Eye cosmetics.

    Science.gov (United States)

    Draelos, Z K

    1991-01-01

    Eye cosmetics are useful to highlight and emphasize the eyes. Currently available eye cosmetics include eye shadows, eye shadow setting creams, under-eye concealers, eye-liners, mascaras, artificial eyelashes, and eyebrow pencils. Special care must be taken when patients with sensitive skin or contact lens wearers select eye cosmetics. Eye cosmetics may also be the cause of either irritant or allergic contact dermatitis, which are two causes of the upper-eyelid dermatitis syndrome.

  18. A novel EOG/EEG hybrid human-machine interface adopting eye movements and ERPs: application to robot control.

    Science.gov (United States)

    Ma, Jiaxin; Zhang, Yu; Cichocki, Andrzej; Matsuno, Fumitoshi

    2015-03-01

    This study presents a novel human-machine interface (HMI) based on both electrooculography (EOG) and electroencephalography (EEG). This hybrid interface works in two modes: an EOG mode recognizes eye movements such as blinks, and an EEG mode detects event related potentials (ERPs) like P300. While both eye movements and ERPs have been separately used for implementing assistive interfaces, which help patients with motor disabilities in performing daily tasks, the proposed hybrid interface integrates them together. In this way, both the eye movements and ERPs complement each other. Therefore, it can provide a better efficiency and a wider scope of application. In this study, we design a threshold algorithm that can recognize four kinds of eye movements including blink, wink, gaze, and frown. In addition, an oddball paradigm with stimuli of inverted faces is used to evoke multiple ERP components including P300, N170, and VPP. To verify the effectiveness of the proposed system, two different online experiments are carried out. One is to control a multifunctional humanoid robot, and the other is to control four mobile robots. In both experiments, the subjects can complete tasks effectively by using the proposed interface, whereas the best completion time is relatively short and very close to the one operated by hand.

  19. Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression

    DEFF Research Database (Denmark)

    Eiberg, Hans; Troelsen, Jesper; Boyd, Mette

    2008-01-01

    The human eye color is a quantitative trait displaying multifactorial inheritance. Several studies have shown that the OCA2 locus is the major contributor to the human eye color variation. By linkage analysis of a large Danish family, we finemapped the blue eye color locus to a 166 Kbp region...... within the HERC2 gene. By association analyses, we identified two SNPs within this region that were perfectly associated with the blue and brown eye colors: rs12913832 and rs1129038. Of these, rs12913832 is located 21.152 bp upstream from the OCA2 promoter in a highly conserved sequence in intron 86...... of HERC2. The brown eye color allele of rs12913832 is highly conserved throughout a number of species. As shown by a Luciferase assays in cell cultures, the element significantly reduces the activity of the OCA2 promoter and electrophoretic mobility shift assays demonstrate that the two alleles bind...

  20. In Vivo Non-Invasive Measurement of Young's Modulus of Elasticity in Human Eyes: A Feasibility Study.

    Science.gov (United States)

    Sit, Arthur J; Lin, Shuai-Chun; Kazemi, Arash; McLaren, Jay W; Pruet, Christopher M; Zhang, Xiaoming

    2017-08-28

    Abnormal ocular biomechanical properties may be important for understanding the risk of glaucoma. However, there are no clinical methods for measuring standard material properties in patients. In this feasibility study we demonstrated proof-of-principle for a novel method, ultrasound surface wave elastography (USWE), to determine the in vivo Young's modulus of elasticity of corneas in normal human eyes. Twenty eyes of 10 healthy subjects (mean age 51.4±7.2;±SD, range 43-64 y) were studied. A spherical-tipped probe (3-mm diameter) was placed on closed eyelids and generated a gentle harmonic vibration at 100 Hz for 0.1 second. Wave speed propagation in the cornea was measured by USWE, and Young's modulus was calculated from the wave speed. Associations between Young's modulus and intraocular pressure (IOP), age, central corneal thickness, and axial length were explored by Pearson correlation. Statistical significance was determined by using generalized estimating equation models to account for possible correlation between fellow eyes. Mean IOP was 12.8±2.7 mm Hg. Mean wave speed in the cornea was 1.82±0.10 m/s. Young's modulus of elasticity was 696±113 kPa and was correlated with IOP (r=0.57; P=0.004), but none of the other variables (P>0.1). USWE is a novel non-invasive technique for measuring ocular biomechanical properties. Corneal Young's modulus in normal eyes is associated with IOP, consistent with measurements in cadaver eyes. Further work is needed to determine elasticity in other ocular tissues, particularly the sclera, and if elasticity is altered in glaucoma patients.

  1. A three-single-nucleotide polymorphism haplotype in intron 1 of OCA2 explains most human eye-color variation.

    Science.gov (United States)

    Duffy, David L; Montgomery, Grant W; Chen, Wei; Zhao, Zhen Zhen; Le, Lien; James, Michael R; Hayward, Nicholas K; Martin, Nicholas G; Sturm, Richard A

    2007-02-01

    We have previously shown that a quantitative-trait locus linked to the OCA2 region of 15q accounts for 74% of variation in human eye color. We conducted additional genotyping to clarify the role of the OCA2 locus in the inheritance of eye color and other pigmentary traits associated with skin-cancer risk in white populations. Fifty-eight synonymous and nonsynonymous exonic single-nucleotide polymorphisms (SNPs) and tagging SNPs were typed in a collection of 3,839 adolescent twins, their siblings, and their parents. The highest association for blue/nonblue eye color was found with three OCA2 SNPs: rs7495174 T/C, rs6497268 G/T, and rs11855019 T/C (P values of 1.02x10(-61), 1.57x10(-96), and 4.45x10(-54), respectively) in intron 1. These three SNPs are in one major haplotype block, with TGT representing 78.4% of alleles. The TGT/TGT diplotype found in 62.2% of samples was the major genotype seen to modify eye color, with a frequency of 0.905 in blue or green compared with only 0.095 in brown eye color. This genotype was also at highest frequency in subjects with light brown hair and was more frequent in fair and medium skin types, consistent with the TGT haplotype acting as a recessive modifier of lighter pigmentary phenotypes. Homozygotes for rs11855019 C/C were predominantly without freckles and had lower mole counts. The minor population impact of the nonsynonymous coding-region polymorphisms Arg305Trp and Arg419Gln associated with nonblue eyes and the tight linkage of the major TGT haplotype within the intron 1 of OCA2 with blue eye color and lighter hair and skin tones suggest that differences within the 5' proximal regulatory control region of the OCA2 gene alter expression or messenger RNA-transcript levels and may be responsible for these associations.

  2. Ocular surface area and human eye blink frequency during VDU work

    DEFF Research Database (Denmark)

    Nielsen, Pernille Kofoed; Søgaard, Karen; Skotte, Jørgen

    2008-01-01

    The purpose of this study was to investigate how the ocular surface area (OSA) and the eye blink frequency (BF) are affected by a high versus a low-monitor position during visual display unit (VDU) work with varying cognitive demands. In a balanced randomized (2 x 2) design ten healthy subjects...... (five males, five females) completed two different tasks on the VDU in a simulated office environment (23 degrees C and 30-35% relative humidity); an active task with demands on vision and hand-eye coordination, and a passive task. Two monitor positions were used: high (the monitors' upper edge...... at the same height as the subjects' eyes) and low (lowered by 25 degrees and perpendicular to gaze angle). Each task lasted 10 min. An OSA-proxy was measured from video recordings, and BF was sampled by electrooculography. The effect of lowering the gaze angle by 25 degrees decreased the OSA...

  3. The Relationship Between Temporary Threshold Shift (TTS and Eye Color in Human.

    Directory of Open Access Journals (Sweden)

    Ghasem Mohammad khani

    1996-09-01

    Full Text Available In this article we aimed at studying the function of Melanin in the inner ear. To reach this goal TTS was studied in people with blue or brown eye color. Subjects were 68 male teenagers with normal hearing. Auditory thresholds were obtained by means of high frequency audiometry (.8-8KHzbefore and after TTS. We used narrowband noise with frequency width of 1665-2335Hz, central frequency of 2 KHz, intensity of 105dBSPL and duration of 10 minutes. A significant difference was discovered in the average TTS of this two group in the frequency range of 2-8 KHz. Brown-colored eye boys manifested the least TTS and the blue- colored eyes one the most discovered TTS.

  4. Judgment of the humanness of an interlocutor is in the eye of the beholder

    National Research Council Canada - National Science Library

    Lortie, Catherine L; Guitton, Matthieu J

    2011-01-01

    ...., humans perceived as machine. The Loebner Prize in Artificial Intelligence features humans and artificial agents trying to convince judges on their humanness via computer-mediated communication...

  5. Judgment of the Humanness of an Interlocutor Is in the Eye of the Beholder: e25085

    National Research Council Canada - National Science Library

    Catherine L Lortie; Matthieu J Guitton

    2011-01-01

    ...., humans perceived as machine. The Loebner Prize in Artificial Intelligence features humans and artificial agents trying to convince judges on their humanness via computer-mediated communication...

  6. Multi-contrast imaging of human posterior eye by Jones matrix optical coherence tomography

    Science.gov (United States)

    Yasuno, Yoshiaki

    2017-04-01

    A multi-contrast imaging of pathologic posterior eyes is demonstrated by Jones matrix optical coherence tomography (Jones matrix OCT). The Jones matrix OCT provides five tomographies, which includes scattering, local attenuation, birefringence, polarization uniformity, and optical coherence angiography, by a single scan. The hardware configuration, algorithms of the Jones matrix OCT as well as its application to ophthalmology is discussed.

  7. The Charles F. Prentice Award Lecture 2005: optics of the human eye: progress and problems.

    Science.gov (United States)

    Charman, W Neil

    2006-06-01

    The history of measurements of ocular aberration is briefly reviewed and recent work using much-improved aberrometers and large samples of eyes is summarized. When on-axis, higher-order, monochromatic aberrations are averaged, undercorrected, positive, fourth-order spherical aberration dominates; other Zernike wavefront aberration coefficients have average values near zero. Individually, however, many eyes show substantial amounts of third-order and other fourth-order aberrations; the value of these varies idiosyncratically about zero. Most normal eyes show only small amounts of axial monochromatic aberration for photopic pupils up to around 3 mm; the limits to retinal image quality are then usually set by diffraction, uncorrected or imperfectly corrected spherocylindrical refractive error, accommodation error, and chromatic aberration. Longitudinal chromatic aberration varies very little across the population. With larger mesopic and scotopic pupils, monochromatic aberration plays a more important optical role, but overall visual performance is increasingly dominated by neural factors. Some remaining problems in measuring and modeling the eye's optical performance are discussed.

  8. Application of SV40 T-transformed human corneal epithelial cells to evaluate potential irritant chemicals for in vitro alternative eye toxicity.

    Science.gov (United States)

    Kim, Cho-Won; Park, Geon-Tae; Bae, Ok-Nam; Noh, Minsoo; Choi, Kyung-Chul

    2016-01-01

    Assessment of eye irritation potential is important to human safety, and it is necessary for various cosmetics and chemicals that may contact the human eye. Until recently, the Draize test was considered the standard method for estimating eye irritation, despite its disadvantages such as the need to sacrifice many rabbits for subjective scoring. Thus, we investigated the cytotoxicity and inflammatory response to standard eye irritants using SV40 T-transformed human corneal epithelial (SHCE) cells as a step toward development of an animal-free alternative eye irritation test. MTT and NRU assays of cell viability were performed to investigate the optimal experimental conditions for SHCE cell viability when cells were exposed to sodium dodecyl sulfate (SDS) as a standard eye irritant at 6.25×10(-3) to 1×10(-1)%. Additionally, cell viability of SHCE cells was examined in response to six potential eye irritants, benzalkonium chloride, dimethyl sulfoxide, isopropanol, SDS, Triton X-100 and Tween 20 at 5×10(-3) to 1×10(-1)%. Finally, we estimated the secretion level of cytokines in response to stimulation by eye irritants in SHCE cells. SHCE cells showed a good response to potential eye irritants when the cells were exposed to potential irritants for 10min at room temperature (RT), and cytokine production increased in a concentration-dependent manner, indicating that cytotoxicity and cytokine secretion from SHCE cells may be well correlated with the concentrations of irritants. Taken together, these results suggest that SHCE cells could be an excellent alternative in vitro model to replace in vivo animal models for eye irritation tests. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Characterizing eye movement behaviors and kinematics of non-human primates during virtual navigation tasks.

    Science.gov (United States)

    Corrigan, Benjamin W; Gulli, Roberto A; Doucet, Guillaume; Martinez-Trujillo, Julio C

    2017-10-01

    Virtual environments (VE) allow testing complex behaviors in naturalistic settings by combining highly controlled visual stimuli with spatial navigation and other cognitive tasks. They also allow for the recording of eye movements using high-precision eye tracking techniques, which is important in electrophysiological studies examining the response properties of neurons in visual areas of nonhuman primates. However, during virtual navigation, the pattern of retinal stimulation can be highly dynamic which may influence eye movements. Here we examine whether and how eye movement patterns change as a function of dynamic visual stimulation during virtual navigation tasks, relative to standard oculomotor tasks. We trained two rhesus macaques to use a joystick to navigate in a VE to complete two tasks. To contrast VE behavior with classic measurements, the monkeys also performed a simple Cued Saccade task. We used a robust algorithm for rapid classification of saccades, fixations, and smooth pursuits. We then analyzed the kinematics of saccades during all tasks, and specifically during different phases of the VE tasks. We found that fixation to smooth pursuit ratios were smaller in VE tasks (4:5) compared to the Cued Saccade task (7:1), reflecting a more intensive use of smooth pursuit to foveate targets in VE than in a standard visually guided saccade task or during spontaneous fixations. Saccades made to rewarded targets (exploitation) tended to have increased peak velocities compared to saccades made to unrewarded objects (exploration). VE exploitation saccades were 6% slower than saccades to discrete targets in the Cued Saccade task. Virtual environments represent a technological advance in experimental design for nonhuman primates. Here we provide a framework to study the ways that eye movements change between and within static and dynamic displays.

  10. Setting targets for human resources for eye health in sub-Saharan Africa: what evidence should be used?

    Science.gov (United States)

    Courtright, Paul; Mathenge, Wanjiku; Kello, Amir Bedri; Cook, Colin; Kalua, Khumbo; Lewallen, Susan

    2016-03-16

    With a global target set at reducing vision loss by 25% by the year 2019, sub-Saharan Africa with an estimated 4.8 million blind persons will require human resources for eye health (HReH) that need to be available, appropriately skilled, supported, and productive. Targets for HReH are useful for planning, monitoring, and resource mobilization, but they need to be updated and informed by evidence of effectiveness and efficiency. Supporting evidence should take into consideration (1) ever-changing disease-specific issues including the epidemiology, the complexity of diagnosis and treatment, and the technology needed for diagnosis and treatment of each condition; (2) the changing demands for vision-related services of an increasingly urbanized population; and (3) interconnected health system issues that affect productivity and quality. The existing targets for HReH and some of the existing strategies such as task shifting of cataract surgery and trichiasis surgery, as well as the scope of eye care interventions for primary eye care workers, will need to be re-evaluated and re-defined against such evidence or supported by new evidence.

  11. RESEARCH OF LINEAR AND NONLINEAR PROCESSES AT FEMTOSECOND LASER RADIATION PROPAGATION IN THE MEDIUM SIMULATING THE HUMAN EYE VITREOUS

    Directory of Open Access Journals (Sweden)

    P. Y. Rogov

    2015-09-01

    Full Text Available The paper deals with mathematical model of linear and nonlinear processes occurring at the propagation of femtosecond laser pulses in the vitreous of the human eye. Methods of computing modeling are applied for the nonlinear spectral equation solution describing the dynamics of a two-dimensional TE-polarized radiation in a homogeneous isotropic medium with cubic fast-response nonlinearity without the usage of slowly varying envelope approximation. Environments close to the optical media parameters of the eye were used for the simulation. The model of femtosecond radiation propagation takes into account the process dynamics for dispersion broadening of pulses in time and the occurence of the self-focusing near the retina when passing through the vitreous body of the eye. Dependence between the pulse duration on the retina has been revealed and the duration of the input pulse and the values of power density at which there is self-focusing have been found. It is shown that the main mechanism of radiation damage with the use of titanium-sapphire laser is photoionization. The results coincide with those obtained by the other scientists, and are usable for creation Russian laser safety standards for femtosecond laser systems.

  12. Design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye

    Science.gov (United States)

    Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Iturbide-Jiménez, F.; Martínez-López, M.; Ramírez-Como, M.; Armengol-Cruz, V.; Vásquez-Báez, I.

    2014-09-01

    Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.

  13. Coupling Osmolarity Dynamics within Human Tear Film on an Eye-Shaped Domain

    Science.gov (United States)

    Li, Longfei; Braun, R. J.; Driscoll, T. A.; Henshaw, W. D.; Banks, J. W.; King-Smith, P. E.

    2013-11-01

    The concentration of ions in the tear film (osmolarity) is a key variable in understanding dry eye symptoms and disease. We derived a mathematical model that couples osmolarity (treated as a single solute) and fluid dynamics within the tear film on a 2D eye-shaped domain. The model concerns the physical effects of evaporation, surface tension, viscosity, ocular surface wettability, osmolarity, osmosis and tear fluid supply and drainage. We solved the governing system of coupled nonlinear PDEs using the Overture computational framework developed at LLNL, together with a new hybrid time stepping scheme (using variable step BDF and RKC) that was added to the framework. Results of our numerical simulations show good agreement with existing 1D models (for both tear film and osmolarity dynamics) and provide new insight about the osmolarity distribution over the ocular surface during the interblink.

  14. Quick-Eye: Examination of Human Performance Characteristics Using Eye Tracking and Manual-Based Control Systems for Monitoring Multiple Displays

    Science.gov (United States)

    2013-03-01

    primary eye movements, fixations and saccades . Fixations can be described as the process where the eyes are focusing on an aspect in the environment for...the purpose of gaining visual information. Saccades , conversely, are the rapid transition movements between fixations [3]. Hayhoe and Ballard... Reading and Information Processing: 20 Years of Research," Psychological Bulletin, vol. 124, no. 3, pp. 373–422, 1998. [4] M. Hayhoe and D. Ballard

  15. Laser interferential diagnostics of retinal visual acuity of the human eye with cataract

    Science.gov (United States)

    Chaussky, Anatoly A.; Ryabukho, Vladimir P.; Tuchin, Valery V.; Akchurin, Garif G.; Bakutkin, Valery V.; Radchenko, Elena Y.; Nazaryants, Vitaly

    1999-04-01

    In the paper theoretical and experimental study of forming of interference pattern with a high contrast at the retina cataractous eye is presented. The high contrast of retinal fringes is reached by control of the parameters of incident beam with regular interference fringes. Experimental result have been done for the model objects that can be described in the framework of 'random phase screen' approximation. Some recommendations for clinical application are suggested.

  16. Determination of chromatic aberration in the human eye by means of Fresnel propagation theory

    OpenAIRE

    Mas Candela, David; Pérez Rodríguez, Jorge; Illueca Contri, Carlos; Espinosa Tomás, Julián; Hernández Poveda, Consuelo; Vázquez Ferri, Carmen; Miret Marí, Juan José

    2005-01-01

    In this communication, the authors have determined the longitudinal chromatic aberrations in real eyes. The method that has been used combines real data of corneal morphology, central thickness of crystalline lens and biometric measures of axial length together with numerical calculation of the propagation process. The curvature of the crystalline lens has been adjusted to different curvature models and refractive index distributions. The wavelength dependence of all ocular media has been mod...

  17. [A tracking function of human eye in microgravity and during readaptation to earth's gravity].

    Science.gov (United States)

    Kornilova, L N

    2001-01-01

    The paper summarizes results of electro-oculography of all ways of visual tracking: fixative eye movements (saccades), smooth pursuit of linearly, pendulum-like and circularly moving point stimuli, pursuit of vertically moving foveoretinal optokinetic stimuli, and presents values of thresholds and amplification coefficients of the optokinetic nystagmus during tracking of linear movement of foveoretinal optokinetic stimuli. Investigations were performed aboard the Salyut and Mir space stations with participation of 31 cosmonauts of whom 27 made long-term (76 up to 438 day) and 4 made short-term (7 to 9 day) missions. It was shown that in space flight the saccadic structure within the tracking reaction does not change; yet, corrective movements (additional microsaccades to achieve tracking) appeared in 47% of observations at the onset and in 76% of observations on months 3 to 6 of space flight. After landing, the structure of vertical saccades was found altered in half the cosmonauts. No matter in or after flight, reverse nystagmus was present along with the gaze nystagmus during static saccades in 22% (7 cosmonauts) of the observations. Amplitude of tracking vertically, diagonally or circularly moving stimuli was significantly reduced as period on mission increased. Early in flight (40% of the cosmonauts) and shortly afterwards (21% of the cosmonauts) the structure of smooth tracking reaction was totally broken up, that is eye followed stimulus with micro- or macrosaccades. The structure of smooth eye tracking recovered on flight days 6-8 and on postflight days 3-4. However, in 46% of the cosmonauts on long-term missions the structure of smooth eye tracking was noted to be disturbed periodically, i.e. smooth tracking was replaced by saccadic.

  18. Evaluation of visual acuity and color vision in normal human eyes with a sutureless temporary amniotic membrane patch.

    Science.gov (United States)

    Ijiri, Shigeyuki; Kobayashi, Akira; Sugiyama, Kazuhisa; Tseng, Scheffer C G

    2007-12-01

    To evaluate how sutureless amniotic membrane patches may affect visual functions in normal human eyes. Prospective intervention study. Ten sets of sutureless amniotic membrane patch manufactured as PROKERA were inserted in one eye of six normal patients. Four sets (one each) were inserted in four patients, while six sets (three each) were inserted in two patients. Uncorrected distant and near visual acuities, color vision, amniotic membrane thickness measured by pachymetry, and total symptom scores were compared before and after insertion. Within 30 minutes after insertion, mean distant visual acuities decreased from -0.22 +/- 0.06 to 0.92 +/- 0.45 logarithmic minimum angle of resolution (logMAR). Among 10 sets of PROKERA inserted, the largest optotype (1.0 logMAR) of the near vision chart could not be recognized in five, but color vision evaluated by Panel D-15 was still preserved in all. Total symptom scores increased to 47.8 +/- 9.1 points (maximum, 100 points). Among symptoms, total scores for foreign body sensation (17.8 +/- 3.6) and blurred vision (17.8 +/- 4.4) were high. Loss of distant visual acuity and increases of symptom scores were not correlated with amniotic membrane thickness, of which the mean was 67.6 +/- 25.2 mum. However, amniotic membrane that was less opaque tended to provide relatively good visual acuities. Because of the relative non-transparency of sutureless amniotic membrane patches in PROKERA, distant and near visual acuities decreased in normal human eyes. The foreign body sensation noted after insertion is primarily derived from the rigid supporting skirt.

  19. 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 ...

  20. 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 ...

  1. Eye Injuries

    Science.gov (United States)

    ... 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 work ...

  2. Eye emergencies

    Science.gov (United States)

    ... Keep flushing the eye with clean water or saline for at least 15 minutes. Seek medical help right away. Do not delay. EYE CUT, SCRATCH, OR BLOW Gently apply a clean cold compress to the eye to reduce swelling and ...

  3. Human eye cataract microstructure modeling and its effect on simulated retinal imaging

    Science.gov (United States)

    Fan, Wen-Shuang; Chang, Chung-Hao; Horng, Chi-Ting; Yao, Hsin-Yu; Sun, Han-Ying; Huang, Shu-Fang; Wang, Hsiang-Chen

    2017-02-01

    We designed a crystalline microstructure during cataract lesions and calculated the aberration value of the eye by using ray trace modeling to identify the corresponding spherical aberration, coma aberration, and trefoil aberration value under different pathological-change degrees. The mutual relationship between microstructure and aberration was then discussed using these values. Calculation results showed that with increased layer number of microstructure, the influence of aberration value on spherical aberration was the greatest. In addition, the influence of a relatively compact microstructure on spherical aberration and coma aberration was small, but that on trefoil aberration was great.

  4. Determination of chromatic aberration in the human eye by means of Fresnel propagation theory

    Science.gov (United States)

    Mas, David; Perez, Jorge; Illueca, Carlos; Espinosa, Julian; Hernandez, Consuelo; Vazquez, Carmen; Miret, Juan J.

    2005-09-01

    In this communication, the authors have determined the longitudinal chromatic aberrations in real eyes. The method that has been used combines real data of corneal morphology, central thickness of crystalline lens and biometric measures of axial length together with numerical calculation of the propagation process. The curvature of the crystalline lens has been adjusted to different curvature models and refractive index distributions. The wavelength dependence of all ocular media has been modelled through the Cauchy formula. Propagation through anterior and posterior chambers has been accomplished through numerical calculation of diffraction integral instead of classical ray-tracing approach. This imposes serous restrictions on the number of samples that are needed for a full propagation process. If we are only interested in amplitude calculations the method consists of evaluating propagation from cornea to crystalline lens with a spectrum propagation method. Propagation from the lens to the best image plane is accomplished by a direct calculation of Fresnel integral. With this model, we have obtained the refraction chromatic difference in diopters for several eyes. Results are compared with real measures of the chromatic aberration, showing a good agreement with numerical calculations. The capabilities of the technique have been demonstrated by applying the method to the study of the chromatic aberration of a keratoconus.

  5. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life

    DEFF Research Database (Denmark)

    Lynnerup, Niels; Kjeldsen, Henrik; Heegaard, Steffen

    2008-01-01

    dating is made possible by comparing the (14)C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric (14)C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even...... on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close...... that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14)C content of various tissues may be used to assess...

  6. Sensory versus motor loci for integration of multiple motion signals in smooth pursuit eye movements and human motion perception.

    Science.gov (United States)

    Niu, Yu-Qiong; Lisberger, Stephen G

    2011-08-01

    We have investigated how visual motion signals are integrated for smooth pursuit eye movements by measuring the initiation of pursuit in monkeys for pairs of moving stimuli of the same or differing luminance. The initiation of pursuit for pairs of stimuli of the same luminance could be accounted for as a vector average of the responses to the two stimuli singly. When stimuli comprised two superimposed patches of moving dot textures, the brighter stimulus suppressed the inputs from the dimmer stimulus, so that the initiation of pursuit became winner-take-all when the luminance ratio of the two stimuli was 8 or greater. The dominance of the brighter stimulus could be not attributed to either the latency difference or the ratio of the eye accelerations for the bright and dim stimuli presented singly. When stimuli comprised either spot targets or two patches of dots moving across separate locations in the visual field, the brighter stimulus had a much weaker suppressive influence; the initiation of pursuit could be accounted for by nearly equal vector averaging of the responses to the two stimuli singly. The suppressive effects of the brighter stimulus also appeared in human perceptual judgments, but again only for superimposed stimuli. We conclude that one locus of the interaction of two moving visual stimuli is shared by perception and action and resides in local inhibitory connections in the visual cortex. A second locus resides deeper in sensory-motor processing and may be more closely related to action selection than to stimulus selection.

  7. Psychophysical and perceptual performance in a simulated-scotoma model of human eye injury

    Science.gov (United States)

    Brandeis, R.; Egoz, I.; Peri, D.; Sapiens, N.; Turetz, J.

    2008-02-01

    Macular scotomas, affecting visual functioning, characterize many eye and neurological diseases like AMD, diabetes mellitus, multiple sclerosis, and macular hole. In this work, foveal visual field defects were modeled, and their effects were evaluated on spatial contrast sensitivity and a task of stimulus detection and aiming. The modeled occluding scotomas, of different size, were superimposed on the stimuli presented on the computer display, and were stabilized on the retina using a mono Purkinje Eye-Tracker. Spatial contrast sensitivity was evaluated using square-wave grating stimuli, whose contrast thresholds were measured using the method of constant stimuli with "catch trials". The detection task consisted of a triple conjunctive visual search display of: size (in visual angle), contrast and background (simple, low-level features vs. complex, high-level features). Search/aiming accuracy as well as R.T. measures used for performance evaluation. Artificially generated scotomas suppressed spatial contrast sensitivity in a size dependent manner, similar to previous studies. Deprivation effect was dependent on spatial frequency, consistent with retinal inhomogeneity models. Stimulus detection time was slowed in complex background search situation more than in simple background. Detection speed was dependent on scotoma size and size of stimulus. In contrast, visually guided aiming was more sensitive to scotoma effect in simple background search situation than in complex background. Both stimulus aiming R.T. and accuracy (precision targeting) were impaired, as a function of scotoma size and size of stimulus. The data can be explained by models distinguishing between saliency-based, parallel and serial search processes, guiding visual attention, which are supported by underlying retinal as well as neural mechanisms.

  8. Pathology of 219 human cadaver eyes with 1-piece or 3-piece hydrophobic acrylic intraocular lenses: capsular bag opacification and sites of square-edged barrier breach.

    Science.gov (United States)

    Ness, Peter J; Werner, Liliana; Maddula, Surekha; Davis, Don; Zaugg, Brian; Stringham, Jack; Burrow, Michael; Yeh, Oliver

    2011-05-01

    To assess capsular bag opacification and sites of initial posterior capsule opacification (PCO) in human cadaver eyes with square-edged 1-piece or 3-piece hydrophobic acrylic intraocular lenses (IOLs). John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Eyes were immersed in 10% formalin after enucleation and had anterior segment scanning with very-high-frequency ultrasound (Artemis). After the eyes were sectioned at the equator, gross examination of the anterior segment was performed from the posterior aspect to assess capsular bag opacification, anterior capsule coverage of the IOL edge, and IOL fixation. Selected eyes had histopathologic examination. One hundred nineteen eyes with 1-piece IOLs and 100 with 3-piece IOLs were included in the analyses of capsular bag opacification. There was no difference in central (P=.29) or peripheral (P=.76) PCO. In 63 of 84 eyes with a 1-piece IOL and peripheral PCO, the optic-haptic junction was the site of initiation. In eyes with a 3-piece IOL, initial peripheral PCO was observed at nearly the same rate whether there was full 360-degree anterior capsulorhexis overlap of the optic or no overlap (P=.13). In the latter, the site of PCO initiation was in areas lacking capsulorhexis coverage in 46% of eyes. There was no difference in central or peripheral PCO between 1-piece and 3-piece hydrophobic acrylic IOLs. With 1-piece IOLs, PCO tended to start at the optic-haptic junctions. With 3-piece IOLs, full anterior capsule coverage did not produce a statistically significant benefit with respect to PCO prevention. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  9. About the Eye

    Medline Plus

    Full Text Available ... D., Deputy Clinical Director Education Programs National Eye Health Education Program (NEHEP) Diabetic Eye Disease Education Program Glaucoma ... NEI Office of Science Communications, Public Liaison, and Education. Technical questions ... of Health and Human Services | The National Institutes of Health | ...

  10. 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

  11. Delineation of motoneuron subgroups supplying individual eye muscles in the human oculomotor nucleus

    OpenAIRE

    Che Ngwa, Emmanuel; Zeeh, Christina; Messoudi, Ahmed; Büttner-Ennever, Jean A.; Horn, Anja K. E.

    2014-01-01

    The oculomotor nucleus (nIII) contains the motoneurons of medial, inferior, and superior recti (MR, IR, and SR), inferior oblique (IO), and levator palpebrae (LP) muscles. The delineation of motoneuron subgroups for each muscle is well-known in monkey, but not in human. We studied the transmitter inputs to human nIII and the trochlear nucleus (nIV), which innervates the superior oblique muscle (SO), to outline individual motoneuron subgroups. Parallel series of sections from human brainstems ...

  12. Delineation of motoneuron subgroups supplying individual eye muscles in the human oculomotor nucleus

    OpenAIRE

    Emmanuel eChe-Ngwa; Christina eZeeh; Christina eZeeh; Ahmed eMessoudi; Jean Alice Büttner-Ennever; Anja Kerstin Ellen Horn; Anja Kerstin Ellen Horn

    2014-01-01

    The oculomotor nucleus (nIII) contains the motoneurons of medial, inferior and superior recti (MR, IR, SR), inferior oblique (IO) and levator palpebrae (LP) muscles. The delineation of motoneuron subgroups for each muscle is well-known in monkey, but not in human. We studied the transmitter inputs to human nIII and the trochlear nucleus (nIV), which innervates the superior oblique muscle (SO), to outline individual motoneuron subgroups. Parallel series of sections from human brainstems were i...

  13. Opening our eyes to a critical approach to medicine: The humanities in medical education.

    Science.gov (United States)

    Liao, Lester

    2017-02-01

    This paper examines a recent medical graduate's perspective on how undergraduate education tends to focus on imparting medical knowledge with little reference to the human aspects in clinical medicine. This is problematic because medicine is both about people and practiced by people. Students often have minimal exposure to the humanities prior to and in medical school and are frequently unaware of the societal trends that impact their view of medical practice. Familiarity with the humanities is a crucial means to understanding human nature, recognizing personal sociocultural biases, and practicing patient-centered medicine. This gap in knowledge may be due to the increase in medical information and optimistic ideologies related to medical progress. Philosophical paradigms and historical examples are considered to demonstrate the relevance of both fields in the humanities in understanding the role of moral human agents in applying medical knowledge. Educational changes in the humanities are proposed as a potential solution to our current deficits. Informal changes include mentorship relationships and shifting the general underpinning attitude in medical culture. Formal changes include specific courses teaching a critical approach to medicine. Changes in competency-based education and admissions are also suggested. These amendments are proposed to practice a fuller, truly human medicine.

  14. Eye-head stabilization mechanism for a humanoid robot tested on human inertial data

    DEFF Research Database (Denmark)

    Vannucci, Lorenzo; Falotico, Egidio; Tolu, Silvia

    2016-01-01

    Two main classes of reflexes relying on the vestibular system are involved in the stabilization of the human gaze: the vestibulocollic reflex (VCR), which stabilizes the head in space and the vestibulo-ocular reflex (VOR), which stabilizes the visual axis to minimize retinal image motion. Together...... torso disturbance acquired on human subject performing various locomotion tasks confirm the effectiveness of our approach....

  15. Human Rights and the Ethno-Nationalist Problematic through the Eyes of Greek-Cypriot Teachers

    Science.gov (United States)

    Zembylas, Michalinos; Charalambous, Panayiota; Charalambous, Constadina; Lesta, Stalo

    2016-01-01

    The present article aims to examine the interplay between the transnational discourses of human rights and the particularities of local constructions and conceptualisations of human rights within the context of an ethnically divided society, Cyprus. Specifically, this interplay is examined through a qualitative study of Greek-Cypriot primary…

  16. Analysis of the Viscoelastic Properties of the Human Cornea Using Scheimpflug Imaging in Inflation Experiment of Eye Globes

    Science.gov (United States)

    Lombardo, Giuseppe; Serrao, Sebastiano; Rosati, Marianna; Lombardo, Marco

    2014-01-01

    Purpose To demonstrate a Scheimpflug-based imaging procedure for investigating the depth- and time-dependent strain response of the human cornea to inflation testing of whole eye globes. Methods Six specimens, three of which with intact corneal epithelium, were mounted in a customized apparatus within a humidity and temperature-monitored wet chamber. Each specimen was subjected to two mechanical tests in order to measure corneal strain resulting from application of cyclic (cyclic regimen) and constant (creep regimen) stress by changing the intra-ocular pressure (IOP) within physiological ranges (18–42 mmHg). Corneal shape changes were analyzed as a function of IOP and both corneal stress-strain curves and creep curves were generated. Results The procedure was highly accurate and repeatable. Upon cyclic stress application, a biomechanical corneal elasticity gradient was found in the front-back direction. The average Young's modulus of the anterior cornea ranged between 2.28±0.87 MPa and 3.30±0.90 MPa in specimens with and without intact epithelium (P = 0.05) respectively. The Young's modulus of the posterior cornea was on average 0.21±0.09 MPa and 0.17±0.06 MPa (P>0.05) respectively. The time-dependent strain response of the cornea to creep testing was quantified by fitting data to a modified Zener model for extracting both the relaxation time and compliance function. Conclusion Cyclic and creep mechanical tests are valuable for investigating the strain response of the intact human cornea within physiological IOP ranges, providing meaningful results that can be translated to clinic. The presence of epithelium influences the results of anterior corneal shape changes when monitoring deformation via Scheimpflug imaging in inflation experiments of whole eye globes. PMID:25397674

  17. Analysis of the viscoelastic properties of the human cornea using Scheimpflug imaging in inflation experiment of eye globes.

    Directory of Open Access Journals (Sweden)

    Giuseppe Lombardo

    Full Text Available PURPOSE: To demonstrate a Scheimpflug-based imaging procedure for investigating the depth- and time-dependent strain response of the human cornea to inflation testing of whole eye globes. METHODS: Six specimens, three of which with intact corneal epithelium, were mounted in a customized apparatus within a humidity and temperature-monitored wet chamber. Each specimen was subjected to two mechanical tests in order to measure corneal strain resulting from application of cyclic (cyclic regimen and constant (creep regimen stress by changing the intra-ocular pressure (IOP within physiological ranges (18-42 mmHg. Corneal shape changes were analyzed as a function of IOP and both corneal stress-strain curves and creep curves were generated. RESULTS: The procedure was highly accurate and repeatable. Upon cyclic stress application, a biomechanical corneal elasticity gradient was found in the front-back direction. The average Young's modulus of the anterior cornea ranged between 2.28±0.87 MPa and 3.30±0.90 MPa in specimens with and without intact epithelium (P = 0.05 respectively. The Young's modulus of the posterior cornea was on average 0.21±0.09 MPa and 0.17±0.06 MPa (P>0.05 respectively. The time-dependent strain response of the cornea to creep testing was quantified by fitting data to a modified Zener model for extracting both the relaxation time and compliance function. CONCLUSION: Cyclic and creep mechanical tests are valuable for investigating the strain response of the intact human cornea within physiological IOP ranges, providing meaningful results that can be translated to clinic. The presence of epithelium influences the results of anterior corneal shape changes when monitoring deformation via Scheimpflug imaging in inflation experiments of whole eye globes.

  18. SU-G-IeP4-09: Method of Human Eye Aberration Measurement Using Plenoptic Camera Over Large Field of View

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Yang; Wang, Ruixing; Ma, Haotong; Zhang, Xuanzhe; Ning, Yu; Xu, Xiaojun [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha (China)

    2016-06-15

    Purpose: The measurement based on Shack-Hartmann wave-front sensor(WFS), obtaining both the high and low order wave-front aberrations simultaneously and accurately, has been applied in the detection of human eyes aberration in recent years. However, Its application is limited by the small field of view (FOV), slight eye movement leads the optical bacon image exceeds the lenslet array which result in uncertain detection error. To overcome difficulties of precise eye location, the capacity of detecting eye wave-front aberration over FOV much larger than simply a single conjugate Hartmann WFS accurately and simultaneously is demanded. Methods: Plenoptic camera’s lenslet array subdivides the aperture light-field in spatial frequency domain, capture the 4-D light-field information. Data recorded by plenoptic cameras can be used to extract the wave-front phases associated to the eyes aberration. The corresponding theoretical model and simulation system is built up in this article to discuss wave-front measurement performance when utilizing plenoptic camera as wave-front sensor. Results: The simulation results indicate that the plenoptic wave-front method can obtain both the high and low order eyes wave-front aberration with the same accuracy as conventional system in single visual angle detectionand over FOV much larger than simply a single conjugate Hartmann systems. Meanwhile, simulation results show that detection of eye aberrations wave-front in different visual angle can be achieved effectively and simultaneously by plenoptic method, by both point and extended optical beacon from the eye. Conclusion: Plenoptic wave-front method possesses the feasibility in eye aberrations wave-front detection. With larger FOV, the method can effectively reduce the detection error brought by imprecise eye location and simplify the eye aberrations wave-front detection system comparing with which based on Shack-Hartmann WFS. Unique advantage of the plenoptic method lies in obtaining

  19. Correlations between refractive error and biometric parameters in human eyes using the LenStar 900.

    Science.gov (United States)

    O'Donnell, Clare; Hartwig, Andreas; Radhakrishnan, Hema

    2011-02-01

    To investigate the relationship between refractive error and ocular biometry in healthy subjects using a new optical low coherence reflectometry device. Biometric measurements were obtained with a LenStar LS 900 (Haag Streit, Switzerland) on one eye of 70 phakic subjects (mean ± SD age; 29 ± 9 years). Forty myopes and 30 non-myopes (best sphere range -9.63 D to +0.63 D) were included. Outcome measures were compared for the two groups using one way between groups ANOVA. These included; keratometry, central corneal thickness, iris width, anterior chamber depth, pupil diameter, lens thickness, axial length and retinal thickness. No mydriatic or cycloplegic agents were used. There were significant differences between groups for keratometry readings (p = 0.021 and p = 0.038 for steep and flat k readings respectively), anterior chamber depth (p = 0.001), lens thickness (p = 0.026) and axial length (pbiometric parameters assessed and provides information about the relationships between these biometric parameters and age. The results, coupled with a unique ability to image and analyse the ocular structures non-invasively make the LenStar a promising new instrument for ocular evaluation in research and clinical practice. Copyright © 2010 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  20. Theoretical effect of refractive error and accommodation on longitudinal chromatic aberration of the human eye.

    Science.gov (United States)

    Atchison, D A; Smith, G; Waterworth, M D

    1993-09-01

    Simple formulas based on reduced eyes have been developed to predict the variation in longitudinal chromatic aberration with variation in ametropia or accommodation. Two formulas were developed, one for axial ametropia and one for refractive ametropia. The latter also served as a model for accommodation. The results using the formulas are in close agreement with results obtained using raytracing through more sophisticated models. Combining the results of different methods gives the following predictions of change in chromatic difference of focus, between wavelengths of 400 and 700 nm, with change in each diopter of refractive error or accommodation: axial ametropia 0.012 to 0.017 D (0.6 to 0.9%), refractive ametropia 0.05 D (2.2 to 2.4%), and accommodation 0.04 to 0.05 D (2.1 to 2.6%). The chromatic aberration effects of correcting lenses with low dispersion are intermediate in effect and opposite in sign to the effects of corresponding degrees of axial ametropia and refractive ametropia.

  1. Effect of optical correction and remaining aberrations on peripheral resolution acuity in the human eye.

    Science.gov (United States)

    Lundström, Linda; Manzanera, Silvestre; Prieto, Pedro M; Ayala, Diego B; Gorceix, Nicolas; Gustafsson, Jörgen; Unsbo, Peter; Artal, Pablo

    2007-10-01

    Retinal sampling poses a fundamental limit to resolution acuity in the periphery. However, reduced image quality from optical aberrations may also influence peripheral resolution. In this study, we investigate the impact of different degrees of optical correction on acuity in the periphery. We used an adaptive optics system to measure and modify the off-axis aberrations of the right eye of six normal subjects at 20 degrees eccentricity. The system consists of a Hartmann-Shack sensor, a deformable mirror, and a channel for visual testing. Four different optical corrections were tested, ranging from foveal sphero-cylindrical correction to full correction of eccentric low- and high-order monochromatic aberrations. High-contrast visual acuity was measured in green light using a forced choice procedure with Landolt C's, viewed via the deformable mirror through a 4.8-mm artificial pupil. The Zernike terms mainly induced by eccentricity were defocus and with- and against-the-rule astigmatism and each correction condition was successfully implemented. On average, resolution decimal visual acuity improved from 0.057 to 0.061 as the total root-mean-square wavefront error changed from 1.01 mum to 0.05 mum. However, this small tendency of improvement in visual acuity with correction was not significant. The results suggest that for our experimental conditions and subjects, the resolution acuity in the periphery cannot be improved with optical correction.

  2. The human pineal gland: a review of the "third eye" and the effect of light

    National Research Council Canada - National Science Library

    Booth, F M

    1987-01-01

    The human pineal gland is an extremely active neuroendocrine transducer. Environmental light acts through the retina and entrains the pineal gland's circadian rhythms by way of the hypothalamus and sympathetic nervous system...

  3. Real Time Eye Tracking and Hand Tracking Using Regular Video Cameras for Human Computer Interaction

    Science.gov (United States)

    2011-01-01

    Expo (ICME 2010), July 2010, Singapore. (15% acceptance rate)  Kaoning Hu, Shaun Canavan , and Lijun Yin, “Hand pointing estimation for human computer...Computing, Dec. 2009. Las Vegas, NV  Shaun Canavan and Lijun Yin, Dynamic face appearance modeling and sight direction estimation based on local...Kaoning Hu, Shaun Canavan , and Lijun Yin, “Hand pointing estimation for human computer interaction based on two orthogonal views”, IEEE/IAPR

  4. Lasik eye surgery - slideshow

    Science.gov (United States)

    ... presentations/100206.htm Lasik eye surgery - series—Normal anatomy To use the sharing features on this page, ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  5. 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 | ...

  6. PARACRINE AND AUTOCRINE INTERACTIONS IN THE HUMAN ISLET: MORE THAN MEETS THE EYE

    Science.gov (United States)

    Caicedo, Alejandro

    2012-01-01

    The pancreatic islet secretes the hormones insulin and glucagon to regulate glucose metabolism. To generate an adequate secretory response, islet endocrine cells must receive multiple regulatory signals relaying information about changes in the internal and external environments. Islet cells also need to be made aware about the functional status of neighboring cells through paracrine interactions. All this information is used to orchestrate a hormonal response that contributes to glucose homeostasis. Several neurotransmitters have been proposed to work as paracrine signals in the islet. Most of these, however, have yet to meet the criteria to be considered bona fide paracrine signals, in particular in human islets. Here, we review recent findings describing autocrine and paracrine signaling mechanisms in human islets. These recent results are showing an increasingly complex picture of paracrine interactions in the human islet and emphasize that results from other species cannot be readily extrapolated to the human context. Investigators are unveiling new signaling mechanisms or finding new roles for known paracrine signals in human islets. While it is too early to provide a synthesis, the field of islet research is defining the paracrine and autocrine components that will be used to generate models about how islet function is regulated. Meanwhile, the identified signaling pathways can be proposed as therapeutic targets for treating diabetes, a devastating disease affecting millions worldwide. PMID:23022232

  7. Immunohistochemical markers for corneal stem cells in the early developing human eye

    DEFF Research Database (Denmark)

    Lyngholm, Mikkel; Høyer, Poul E; Vorum, Henrik

    2008-01-01

    markers and potential markers for LSCs and early transient amplifying cells in human adults. In this study, we describe the development of the ectodermally derived LSCs and the mesodermally derived niche cells from the time at which the cornea is defined (week 6) until the formation of the early limbal...... niche (week 14) in human embryos and fetuses. The expression of SOD2 and CK15 was investigated together with other recently identified limbal proteins. Previously suggested LSC and differentiation markers (PAX6, aquaporin-1 and nestin) were also investigated. Both SOD2 and CK15 were present...

  8. Mapping human resources for eye health in 21 countries of sub-Saharan Africa: current progress towards VISION 2020.

    Science.gov (United States)

    Palmer, Jennifer J; Chinanayi, Farai; Gilbert, Alice; Pillay, Devan; Fox, Samantha; Jaggernath, Jyoti; Naidoo, Kovin; Graham, Ronnie; Patel, Daksha; Blanchet, Karl

    2014-08-15

    Development of human resources for eye health (HReH) is a major focus of the Global Action Plan 2014 to 2019 to reduce the prevalence of avoidable visual impairment by 25% by the year 2019. The eye health workforce is thought to be much smaller in sub-Saharan Africa than in other regions of the world but data to support this for policy-making is scarce. We collected HReH and cataract surgeries data from 21 countries in sub-Sahara to estimate progress towards key suggested population-based VISION 2020 HReH indicators and cataract surgery rates (CSR) in 2011. Routinely collected data on practitioner and surgery numbers in 2011 was requested from national eye care coordinators via electronic questionnaires. Telephone and e-mail discussions were used to determine data collection strategies that fit the national context and to verify reported data quality. Information was collected on six practitioner cadres: ophthalmologists, cataract surgeons, ophthalmic clinical officers, ophthalmic nurses, optometrists and 'mid-level refractionists' and combined with publicly available population data to calculate practitioner to population ratios and CSRs. Associations with development characteristics were conducted using Wilcoxon rank sum tests and Spearman rank correlations. HReH data was not easily available. A minority of countries had achieved the suggested VISION 2020 targets in 2011; five countries for ophthalmologists/cataract surgeons, four for ophthalmic nurses/clinical officers and two for CSR. All countries were below target for optometrists, even when other cadres who perform refractions as a primary duty were considered. The regional (sample) ratio for surgeons (ophthalmologists and cataract surgeons) was 2.9 per million population, 5.5 for ophthalmic clinical officers and nurses, 3.7 for optometrists and other refractionists, and 515 for CSR. A positive correlation between GDP and CSR as well as many practitioner ratios was observed (CSR P = 0

  9. Mapping human resources for eye health in 21 countries of sub-Saharan Africa: current progress towards VISION 2020

    Science.gov (United States)

    2014-01-01

    Background Development of human resources for eye health (HReH) is a major focus of the Global Action Plan 2014 to 2019 to reduce the prevalence of avoidable visual impairment by 25% by the year 2019. The eye health workforce is thought to be much smaller in sub-Saharan Africa than in other regions of the world but data to support this for policy-making is scarce. We collected HReH and cataract surgeries data from 21 countries in sub-Sahara to estimate progress towards key suggested population-based VISION 2020 HReH indicators and cataract surgery rates (CSR) in 2011. Methods Routinely collected data on practitioner and surgery numbers in 2011 was requested from national eye care coordinators via electronic questionnaires. Telephone and e-mail discussions were used to determine data collection strategies that fit the national context and to verify reported data quality. Information was collected on six practitioner cadres: ophthalmologists, cataract surgeons, ophthalmic clinical officers, ophthalmic nurses, optometrists and ‘mid-level refractionists’ and combined with publicly available population data to calculate practitioner to population ratios and CSRs. Associations with development characteristics were conducted using Wilcoxon rank sum tests and Spearman rank correlations. Results HReH data was not easily available. A minority of countries had achieved the suggested VISION 2020 targets in 2011; five countries for ophthalmologists/cataract surgeons, four for ophthalmic nurses/clinical officers and two for CSR. All countries were below target for optometrists, even when other cadres who perform refractions as a primary duty were considered. The regional (sample) ratio for surgeons (ophthalmologists and cataract surgeons) was 2.9 per million population, 5.5 for ophthalmic clinical officers and nurses, 3.7 for optometrists and other refractionists, and 515 for CSR. A positive correlation between GDP and CSR as well as many practitioner ratios was observed

  10. Cultural Human Rights and the UNESCO Convention: More than Meets the Eye?

    NARCIS (Netherlands)

    Donders, Y.; De Beukelaer, C.; Pyykkönen, M.; Singh, J.P.

    2015-01-01

    Shortly after the adoption of the UNESCO Convention on the Protection and Promotion of the Diversity of Cultural Expressions Donders analysed to what extent this Convention could play a role in the advancement of human rights in general and cultural rights in particular, despite the fact that

  11. Effects of Long-Term Exposure to 60 GHz Millimeter-Wavelength Radiation on the Genotoxicity and Heat Shock Protein (Hsp Expression of Cells Derived from Human Eye

    Directory of Open Access Journals (Sweden)

    Shin Koyama

    2016-08-01

    Full Text Available Human corneal epithelial (HCE-T and human lens epithelial (SRA01/04 cells derived from the human eye were exposed to 60 gigahertz (GHz millimeter-wavelength radiation for 24 h. There was no statistically significant increase in the micronucleus (MN frequency in cells exposed to 60 GHz millimeter-wavelength radiation at 1 mW/cm2 compared with sham-exposed controls and incubator controls. The MN frequency of cells treated with bleomycin for 1 h provided positive controls. The comet assay, used to detect DNA strand breaks, and heat shock protein (Hsp expression also showed no statistically significant effects of exposure. These results indicate that exposure to millimeter-wavelength radiation has no effect on genotoxicity in human eye cells.

  12. Simultaneous examination of tear film break-up and the lipid layer of the human eye: a novel model eye for time course simulation of physiologic tear film behavior (Part 2).

    Science.gov (United States)

    Arnold, Stefan; Bruenner, Holger; Langenbucher, Achim

    2010-01-01

    This article describes a model eye created to mimic the three-layered human tear-film. The model replicates the properties of the mucin, liquid and lipid layer as well as the time-course behavior including blinking process and tear film break-up for measurements with the tear film sensor described in Part 1. The setup basically consists of a sphere that is moistened by a dilution of tear film substitute. Therefore, the time point of the first break-up strongly depends on the consistency of the dilution. By means of an integrated heater, the evaporation rate of the artificial tear-film can be increased. To illustrate the applicability of the model eye, exemplary images during tear-film simulation, taken with and without using the heater, are shown. All images were captured by the sensor. Results and other potential applications are briefly discussed. Copyright © 2010. Published by Elsevier GmbH.

  13. Eye Cancer

    Science.gov (United States)

    ... form of childhood eye cancer. Hemangioma is a benign tumor of the choroid and retina that starts in the blood vessels. Other, rare cancers of the eye include: Conjunctival melanoma is a tumor of the conjunctiva, which is ...

  14. 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 ...

  15. A General Education Course in Cultural Astronomy: Exploring the Universe Through Human Eyes

    Science.gov (United States)

    Larsen, Kristine

    2017-01-01

    Astronomy courses for non-science majors (often referred to as Astro 101) are the bread and butter of the general education service obligation of astronomy faculty and programs across the US. Their content has traditionally been a general survey of the solar system, stars and galaxies, or even the entire universe. However, because the audience is students who will not be continuing on in astronomy, there is actually no need to cover a broad range of specific topics. Rather, it is more important to concentrate on the scientific process, and hopefully leave the student with an understanding of the relevance of science in everyday life, regardless of his or her major. As a result, some faculty prefer a more interdisciplinary focus for their Astro 101 classes, for example courses on the search for extraterrestrial life. Another option for general education astronomy courses is what has become known as cultural astronomy. Cultural astronomy focuses on the ways in which astronomical knowledge and belief influences human behavior and social structures. Under this umbrella fall two important areas of study, archaeoastronomy (concentrating on ancient cultures) and enthoastronomy (focusing on extant cultures). Such interdisciplinary courses draw heavily upon archaeology, history, anthropology, art, and other fields more traditionally aligned with the humanities and social sciences than the natural sciences, and therefore can be attractive to students in these non-science majors. In such courses, students experience the “humanity” of science: the important connections between science and the human experience, and how experts in myriad fields contribute in meaningful ways to our understanding of how astronomical knowledge has been constructed and disseminated across time and space. This poster describes the content and pedagogy of a general education course in cultural astronomy for non-science majors that stresses hands-on and experiential learning, including the use of

  16. RNA silencing in white petunia flowers creates pigmentation patterns invisible to the human eye.

    Science.gov (United States)

    Matsubara, Kiyoshi; Kei, Satoko; Koizumi, Mayuko; Kodama, Hiroaki; Ando, Toshio

    2012-06-15

    Modern commercial petunias exhibit a wide range of flower colors, which can be observed in gardens. In this study, we present a petunia cultivar that exhibits a floral pattern that is invisible to humans but is possibly visible to pollinating insects. We show that this hidden pattern is established by differentially localized accumulation of flavonols and cinnamic acid derivatives in the corolla limb. This accumulation is caused by a combination of two distinct mechanisms that inhibit anthocyanin biosynthesis: a loss-of-function mutation in the ANTHOCYANIN2, and localized RNA-silencing of CHALCONE SYNTHASE-A. Copyright © 2012 Elsevier GmbH. All rights reserved.

  17. Analysis of the effects of non-supine sleeping positions on the stress, strain, deformation and intraocular pressure of the human eye

    Science.gov (United States)

    Volpe, Peter A.

    This thesis presents analytical models, finite element models and experimental data to investigate the response of the human eye to loads that can be experienced when in a non-supine sleeping position. The hypothesis being investigated is that non-supine sleeping positions can lead to stress, strain and deformation of the eye as well as changes in intraocular pressure (IOP) that may exacerbate vision loss in individuals who have glaucoma. To investigate the quasi-static changes in stress and internal pressure, a Fluid-Structure Interaction simulation was performed on an axisymmetrical model of an eye. Common Aerospace Engineering methods for analyzing pressure vessels and hyperelastic structural walls are applied to developing a suitable model. The quasi-static pressure increase was used in an iterative code to analyze changes in IOP over time.

  18. Visual Warning Signals Optimized for Human Perception: What the Eye Sees Fastest

    Directory of Open Access Journals (Sweden)

    B. L. Gros

    2005-01-01

    Full Text Available This study aimed to answer the question of how to design a visual warning signal that is most easily seen and produces the quickest reaction time. This is a classic problem of bionic optimization—if one knows the properties of the receiver one can most easily find a suitable solution. Because the peak of the spatio-temporal contrast sensitivity function of the human visual system occurs at non-zero spatial and temporal frequencies, it is likely that movement enhances the detectability of threshold visual signals. Earlier studies employing extended drifting sinewave gratings bear out this prediction. We have studied the ability of human observers to detect threshold visual signals for both moving and stationary stimuli. We used discrete, localized signals such as might be employed in aerospace or automotive warning signal displays. Moving stimuli show a superior detectability to non-moving stimuli of the same integrated energy. Moving stimuli at threshold detectability are seen faster than non-moving threshold stimuli. Under some conditions the speed advantage is over 0.25 seconds. Similar advantages have also been shown to occur for suprathreshold signals.

  19. “Omics” in Human Colostrum and Mature Milk: Looking to Old Data with New Eyes

    Science.gov (United States)

    Fanos, Vassilios; Reali, Alessandra

    2017-01-01

    Human Milk (HM) is the best source for newborn nutrition until at least six months; it exerts anti-inflammatory and anti-infective functions, promotes immune system formation and supports organ development. Breastfeeding could also protect from obesity, diabetes and cardiovascular disease. Furthermore, human colostrum (HC) presents a peculiar role in newborn support as a protective effect against allergic and chronic diseases, in addition to long-term metabolic benefits. In this review, we discuss the recent literature regarding “omics” technologies and growth factors (GF) in HC and the effects of pasteurization on its composition. Our aim was to provide new evidence in terms of transcriptomics, proteomics, metabolomics, and microbiomics, also in relation to maternal metabolic diseases and/or fetal anomalies and to underline the functions of GF. Since HC results are so precious, particularly for the vulnerable pre-terms category, we also discuss the importance of HM pasteurization to ensure donated HC even to neonates whose mothers are unable to provide. To the best of our knowledge, this is the first review analyzing in detail the molecular pattern, microbiota, bioactive factors, and dynamic profile of HC, finding clinical correlations of such mediators with their possible in vivo effects and with the consequent impact on neonatal outcomes. PMID:28783113

  20. "Omics" in Human Colostrum and Mature Milk: Looking to Old Data with New Eyes.

    Science.gov (United States)

    Bardanzellu, Flaminia; Fanos, Vassilios; Reali, Alessandra

    2017-08-07

    Human Milk (HM) is the best source for newborn nutrition until at least six months; it exerts anti-inflammatory and anti-infective functions, promotes immune system formation and supports organ development. Breastfeeding could also protect from obesity, diabetes and cardiovascular disease. Furthermore, human colostrum (HC) presents a peculiar role in newborn support as a protective effect against allergic and chronic diseases, in addition to long-term metabolic benefits. In this review, we discuss the recent literature regarding "omics" technologies and growth factors (GF) in HC and the effects of pasteurization on its composition. Our aim was to provide new evidence in terms of transcriptomics, proteomics, metabolomics, and microbiomics, also in relation to maternal metabolic diseases and/or fetal anomalies and to underline the functions of GF. Since HC results are so precious, particularly for the vulnerable pre-terms category, we also discuss the importance of HM pasteurization to ensure donated HC even to neonates whose mothers are unable to provide. To the best of our knowledge, this is the first review analyzing in detail the molecular pattern, microbiota, bioactive factors, and dynamic profile of HC, finding clinical correlations of such mediators with their possible in vivo effects and with the consequent impact on neonatal outcomes.

  1. Integration of Subretinal Suspension Transplants of Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells in a Large-Eyed Model of Geographic Atrophy.

    Science.gov (United States)

    Petrus-Reurer, Sandra; Bartuma, Hammurabi; Aronsson, Monica; Westman, Sofie; Lanner, Fredrik; André, Helder; Kvanta, Anders

    2017-02-01

    Subretinal suspension transplants of human embryonic stem cell-derived retinal pigment epithelial cells (hESC-RPE) have the capacity to form functional monolayers in naive eyes. We explore hESC-RPE integration when transplanted in suspension to a large-eyed model of geographic atrophy (GA). Derivation of hESC-RPE was performed in a xeno-free and defined manner. Subretinal bleb injection of PBS or sodium iodate (NaIO3) was used to induce a GA-like phenotype. Suspensions of hESC-RPE were transplanted to the subretinal space of naive or PBS-/NaIO3-treated rabbits using a transvitreal pars plana technique. Integration of hESC-RPE was monitored by multimodal real-time imaging and by immunohistochemistry. Subretinal blebs of PBS or NaIO3 caused different degrees of outer neuroretinal degeneration, RPE hyperautofluorescence, focal RPE loss, and choroidal atrophy; that is, hallmark characteristics of GA. In nonpretreated naive eyes, hESC-RPE integrated as subretinal monolayers with preserved overlying photoreceptors, yet not in areas with outer neuroretinal degeneration and native RPE loss. When transplanted to eyes with PBS-/NaIO3-induced degeneration, hESC-RPE failed to integrate. In a large-eyed preclinical model, subretinal suspension transplants of hESC-RPE did not integrate in areas with GA-like degeneration.

  2. Femtosecond laser-induced cavitations in the lens of the human eye

    DEFF Research Database (Denmark)

    Kessel, Line; Nymand, Jose; Harbst, Michael

    2007-01-01

    attempted to define the cavitation threshold in the human lens in vitro using multiphoton effects base d on radiation from a femtosecond 800 nm Ti:Sapphire laser. Cavitations were observed from pulse energy densities exceeding 16 mJ/cm2, but only after several minutes of exposure and not as a result...... of a single laser pulse. This suggests that cavitations were caused by a process which differs ITom the single-pulse cavitations observed at higher intensities. To evaluate whether the release of gas was caused by ionization and plasma formation or by thermal effects, we introduced pauses into the pulse train......, which did not change the total exposure time needed to form a cavitation. This suggests that local heating did not play a significant role in producing the observed phenomenon, suggesting that photochemical reactions may be involved. These results demonstrate that there are several types of ultrafast...

  3. Femtosecond laser-induced cavitations in the lens of the human eye

    DEFF Research Database (Denmark)

    Kessel, Line; Nymand, Jose; Harbst, Michael

    attempted to define the cavitation threshold in the human lens in vitro using multiphoton effects base d on radiation from a femtosecond 800 nm Ti:Sapphire laser. Cavitations were observed from pulse energy densities exceeding 16 mJ/cm2, but only after several minutes of exposure and not as a result...... of a single laser pulse. This suggests that cavitations were caused by a process which differs ITom the single-pulse cavitations observed at higher intensities. To evaluate whether the release of gas was caused by ionization and plasma formation or by thermal effects, we introduced pauses into the pulse train......, which did not change the total exposure time needed to form a cavitation. This suggests that local heating did not play a significant role in producing the observed phenomenon, suggesting that photochemical reactions may be involved. These results demonstrate that there are several types of ultrafast...

  4. Cross-modal recognition of shape from hand to eyes in human newborns.

    Science.gov (United States)

    Streri, Arlette

    2003-01-01

    The hypothesis that the ability to coordinate information between tactual and visual modalities is present at birth and dependent on perceptual inherent structures was tested in human newborns. Using an intersensory paired-preference procedure, we showed that newborns can visually recognize the shape of an object that they have previously manipulated with their right hand, out of sight. This is an experimental evidence that newborns can extract shape information in a tactual format and transform it in a visual format before they have had the opportunity to learn from the pairings of visual and tactual experience. This is contrary to a host of theories and models of perceptual learning, both traditional (empiricist philosophers) and modern (connectionist).

  5. Differentiation between vergence and saccadic functional activity within the human frontal eye fields and midbrain revealed through fMRI.

    Directory of Open Access Journals (Sweden)

    Yelda Alkan

    Full Text Available Eye movement research has traditionally studied solely saccade and/or vergence eye movements by isolating these systems within a laboratory setting. While the neural correlates of saccadic eye movements are established, few studies have quantified the functional activity of vergence eye movements using fMRI. This study mapped the neural substrates of vergence eye movements and compared them to saccades to elucidate the spatial commonality and differentiation between these systems.The stimulus was presented in a block design where the 'off' stimulus was a sustained fixation and the 'on' stimulus was random vergence or saccadic eye movements. Data were collected with a 3T scanner. A general linear model (GLM was used in conjunction with cluster size to determine significantly active regions. A paired t-test of the GLM beta weight coefficients was computed between the saccade and vergence functional activities to test the hypothesis that vergence and saccadic stimulation would have spatial differentiation in addition to shared neural substrates.Segregated functional activation was observed within the frontal eye fields where a portion of the functional activity from the vergence task was located anterior to the saccadic functional activity (z>2.3; p0.2.Functional MRI can elucidate the differences between the vergence and saccade neural substrates within the frontal eye fields and midbrain.

  6. A macaque's-eye view of human insertions and deletions: differences in mechanisms.

    Directory of Open Access Journals (Sweden)

    Erika M Kvikstad

    2007-09-01

    Full Text Available Insertions and deletions (indels cause numerous genetic diseases and lead to pronounced evolutionary differences among genomes. The macaque sequences provide an opportunity to gain insights into the mechanisms generating these mutations on a genome-wide scale by establishing the polarity of indels occurring in the human lineage since its divergence from the chimpanzee. Here we apply novel regression techniques and multiscale analyses to demonstrate an extensive regional indel rate variation stemming from local fluctuations in divergence, GC content, male and female recombination rates, proximity to telomeres, and other genomic factors. We find that both replication and, surprisingly, recombination are significantly associated with the occurrence of small indels. Intriguingly, the relative inputs of replication versus recombination differ between insertions and deletions, thus the two types of mutations are likely guided in part by distinct mechanisms. Namely, insertions are more strongly associated with factors linked to recombination, while deletions are mostly associated with replication-related features. Indel as a term misleadingly groups the two types of mutations together by their effect on a sequence alignment. However, here we establish that the correct identification of a small gap as an insertion or a deletion (by use of an outgroup is crucial to determining its mechanism of origin. In addition to providing novel insights into insertion and deletion mutagenesis, these results will assist in gap penalty modeling and eventually lead to more reliable genomic alignments.

  7. Morphology and Accommodative Function of the Vitreous Zonule in Human and Monkey Eyes

    Science.gov (United States)

    Lütjen-Drecoll, Elke; Kaufman, Paul L.; Wasielewski, Rainer; Ting-Li, Lin

    2010-01-01

    Purpose. To explore the attachments of the posterior zonule and vitreous in relation to accommodation and presbyopia in monkeys and humans. Methods. Novel scanning electron microscopy (SEM) and ultrasound biomicroscopy (UBM) techniques were used to visualize the anterior, intermediate, and posterior vitreous zonule and their connections to the ciliary body, vitreous membrane, lens capsule, and ora serrata, and to characterize their age-related changes and correlate them with loss of accommodative forward movement of the ciliary body. α-Chymotrypsin was used focally to lyse the vitreous zonule and determine the effect on movement of the accommodative apparatus in monkeys. Results. The vitreous attached to the peripheral lens capsule and the ora serrata directly. The pars plana zonule and the posterior tines of the anterior zonule were separated from the vitreous membrane except for strategically placed attachments, collectively termed the vitreous zonule, that may modulate and smooth the forward and backward movements of the entire system. Age-dependent changes in these relationships correlated significantly with loss of accommodative amplitude. Lysis of the intermediate vitreous zonule partially restored accommodative movement. Conclusions. The vitreous zonule system may help to smoothly translate to the lens the driving forces of accommodation and disaccommodation generated by the ciliary muscle, while maintaining visual focus and protecting the lens capsule and ora serrata from acute tractional forces. Stiffening of the vitreous zonular system may contribute to age-related loss of accommodation and offer a therapeutic target for presbyopia. PMID:19815737

  8. Differentiation between vergence and saccadic functional activity within the human frontal eye fields and midbrain revealed through fMRI.

    Science.gov (United States)

    Alkan, Yelda; Biswal, Bharat B; Alvarez, Tara L

    2011-01-01

    Eye movement research has traditionally studied solely saccade and/or vergence eye movements by isolating these systems within a laboratory setting. While the neural correlates of saccadic eye movements are established, few studies have quantified the functional activity of vergence eye movements using fMRI. This study mapped the neural substrates of vergence eye movements and compared them to saccades to elucidate the spatial commonality and differentiation between these systems. The stimulus was presented in a block design where the 'off' stimulus was a sustained fixation and the 'on' stimulus was random vergence or saccadic eye movements. Data were collected with a 3T scanner. A general linear model (GLM) was used in conjunction with cluster size to determine significantly active regions. A paired t-test of the GLM beta weight coefficients was computed between the saccade and vergence functional activities to test the hypothesis that vergence and saccadic stimulation would have spatial differentiation in addition to shared neural substrates. Segregated functional activation was observed within the frontal eye fields where a portion of the functional activity from the vergence task was located anterior to the saccadic functional activity (z>2.3; pvergence but not the saccade data set. Similar functional activation was observed within the following regions of interest: the supplementary eye field, dorsolateral prefrontal cortex, ventral lateral prefrontal cortex, lateral intraparietal area, cuneus, precuneus, anterior and posterior cingulates, and cerebellar vermis. The functional activity from these regions was not different between the vergence and saccade data sets assessed by analyzing the beta weights of the paired t-test (p>0.2). Functional MRI can elucidate the differences between the vergence and saccade neural substrates within the frontal eye fields and midbrain.

  9. A Simple Method for Establishing Adherent Ex Vivo Explant Cultures from Human Eye Pathologies for Use in Subsequent Calcium Imaging and Inflammatory Studies

    Science.gov (United States)

    Veréb, Zoltán; Facskó, Andrea; Hawlina, Marko

    2014-01-01

    A novel, simple, and reproducible method for cultivating pathological tissues obtained from human eyes during surgery was developed using viscoelastic material as a tissue adherent to facilitate cell attachment and expansion and calcium imaging of cultured cells challenged by mechanical and acetylcholine (ACh) stimulation as well as inflammatory studies. Anterior lens capsule-lens epithelial cells (aLC-LECs) from cataract surgery and proliferative diabetic retinopathy (PDR) fibrovascular epiretinal membranes (fvERMs) from human eyes were used in the study. We hereby show calcium signaling in aLC-LECs by mechanical and acetylcholine (ACh) stimulation and indicate presence of ACh receptors in these cells. Furthermore, an ex vivo study model was established for measuring the inflammatory response in fvERMs and aLC-LECs upon TNFα treatment. PMID:25276840

  10. A Simple Method for Establishing Adherent Ex Vivo Explant Cultures from Human Eye Pathologies for Use in Subsequent Calcium Imaging and Inflammatory Studies

    Directory of Open Access Journals (Sweden)

    Sofija Andjelic

    2014-01-01

    Full Text Available A novel, simple, and reproducible method for cultivating pathological tissues obtained from human eyes during surgery was developed using viscoelastic material as a tissue adherent to facilitate cell attachment and expansion and calcium imaging of cultured cells challenged by mechanical and acetylcholine (ACh stimulation as well as inflammatory studies. Anterior lens capsule-lens epithelial cells (aLC-LECs from cataract surgery and proliferative diabetic retinopathy (PDR fibrovascular epiretinal membranes (fvERMs from human eyes were used in the study. We hereby show calcium signaling in aLC-LECs by mechanical and acetylcholine (ACh stimulation and indicate presence of ACh receptors in these cells. Furthermore, an ex vivo study model was established for measuring the inflammatory response in fvERMs and aLC-LECs upon TNFα treatment.

  11. The feasibility of an automated eye-tracking-modified Fagan test of memory for human faces in younger Ugandan HIV-exposed children.

    Science.gov (United States)

    Chhaya, Ronak; Weiss, Jonathan; Seffren, Victoria; Sikorskii, Alla; Winke, Paula M; Ojuka, Julius C; Boivin, Michael J

    2017-05-22

    The Fagan Test of Infant Intelligence (FTII) uses longer gaze length for unfamiliar versus familiar human faces to gauge visual-spatial encoding, attention, and working memory in infants. Our objective was to establish the feasibility of automated eye tracking with the FTII in HIV-exposed Ugandan infants. The FTII was administered to 31 perinatally HIV-exposed noninfected (HEU) Ugandan children 6-12 months of age (11 boys; M = 0.69 years, SD = 0.14; 19 girls; M = 0.79, SD = 0.15). A series of 10 different faces were presented (familiar face exposure for 25 s followed by a gaze preference trial of 15 s with both the familiar and unfamiliar faces). Tobii X2-30 infrared camera for pupil detection provided automated eye-tracking measures of gaze location and length during presentation of Ugandan faces selected to correspond to the gender, age (adult, child), face expression, and orientation of the original FTII. Eye-tracking gaze length for unfamiliar faces was correlated with performance on the Mullen Scales of Early Learning (MSEL). Infants gazed longer at the novel picture compared to familiar across 10 novelty preference trials. Better MSEL cognitive development was correlated with proportionately longer time spent looking at the novel faces (r(30) = 0.52, p = .004); especially for the Fine Motor Cognitive Sub-scale (r(30) = 0.54, p = .002). Automated eye tracking in a human face recognition test proved feasible and corresponded to the MSEL composite cognitive development in HEU infants in a resource-constrained clinical setting. Eye tracking may be a viable means of enhancing the validity and accuracy of other neurodevelopmental measures in at-risk children in sub-Saharan Africa.

  12. Attentional Drift: An Exploratory Study into the Development of an Attention Level Monitoring System Based on Human Eye Fixation

    Science.gov (United States)

    2010-03-01

    participate. Additionally, in order to avoid confounding effects from fatigue and nutrition , participants were screened to ensure that proper... nutrition and adequate rest were achieved prior to executing the experiment. All participants had a minimum of at least seven hours of sleep and had eaten...feature called Gazetrailtm, which enables the experimenter to see a snake -like trail of a preset number of eye-fixation points. The eye-tracking

  13. 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 ...

  14. Tuberculosis; Eye

    African Journals Online (AJOL)

    muscle could present as a painful swelling over the corresponding part of the eye with associated restriction of ocular motility involving the muscle. TUBERCULOSIS OF THE EYE. CORNEA: Primary infection of the cornea is very rare. Corneal involvement is usually due to a hypersentitivity or cross-reaction whereby the.

  15. Eye cosmetics.

    Science.gov (United States)

    O'Donoghue, M N

    2000-10-01

    There are many eye cosmetics available to enhance the beauty or improve the appearance of the face. To prevent infection, most eye cosmetics contain preservatives. Fragrance is usually absent to keep the products as safe as possible. Hypoallergenic products contain fewer ingredients and may be more appropriate for patients with sensitive skin.

  16. 'Goats that stare at men'--revisited: do dwarf goats alter their behaviour in response to eye visibility and head direction of a human?

    Science.gov (United States)

    Nawroth, Christian; von Borell, Eberhard; Langbein, Jan

    2016-05-01

    Being able to recognise when one is being observed by someone else is thought to be adaptive during cooperative or competitive events. In particular for prey species, this ability should be of use in the context of predation. A previous study reported that goats (Capra aegagrus hircus) alter their behaviour according to the body and head orientation of a human experimenter. During a food anticipation task, an experimenter remained in a particular posture for 30 s before delivering a reward, and the goats' active anticipation and standing alert behaviour were analysed. To further evaluate the specific mechanisms at work, we here present two additional test conditions. In particular, we investigated the effects of the eye visibility and head orientation of a human experimenter on the behaviour of the goats (N = 7). We found that the level of the subjects' active anticipatory behaviour was highest in the conditions where the experimenter was directing his head and body towards the goat ('Control' and 'Eyes closed' conditions), but the anticipatory behaviour was significantly decreased when the body ('Head only') or the head and body of the experimenter were directed away from the subject ('Back' condition). For standing alert, we found no significant differences between the three conditions in which the experimenter was directing his head towards the subject ('Control', 'Eyes closed' and 'Head only'). This lack of differences in the expression of standing alert suggests that goats evaluate the direction of a human's head as an important cue in their anticipatory behaviour. However, goats did not respond to the visibility of the experimenter's eyes alone.

  17. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, P; Vaz, P [Technological and Nuclear Institute, Estrada Nacional No 10, 2686-953 Sacavem (Portugal); Zankl, M; Schlattl, H, E-mail: pedro.nogueira@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen-German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  18. Anti-Inflammatory and Antioxidative Effects of Camellia japonica on Human Corneal Epithelial Cells and Experimental Dry Eye: In Vivo and In Vitro Study.

    Science.gov (United States)

    Lee, Hyo Seok; Choi, Joo-Hee; Cui, Lian; Li, Ying; Yang, Jee Myung; Yun, Je-Jung; Jung, Ji Eun; Choi, Won; Yoon, Kyung Chul

    2017-02-01

    To analyze the anti-inflammatory and antioxidative effects of Camellia japonica (CJ) on human corneal epithelial (HCE) cells and its therapeutic effects in a mouse model of experimental dry eye (EDE). Camellia japonica extracts of varying concentrations (0.001%, 0.01%, and 0.1%) were used to treat HCE cells. Dichlorofluorescein diacetate (DCF-DA) and dihydroethidium (DHE) assays were performed. The production of peroxiredoxin (PRX) 1-6 and manganese-dependent superoxide dismutase (MnSOD) in HCE cells was assessed using Western blot analysis. Furthermore, eye drops containing 0.001%, 0.01%, or 0.1% CJ extract or a balanced salt solution (BSS) were applied to the EDE. Clinical parameters were measured 7 days after treatment. The levels of inflammatory markers and intracellular reactive oxygen species (ROS) were measured. Treatment with 0.01% and 0.1% CJ extracts decreased apoptosis in HCE cells. In addition, band intensities of PRX 1, 4, and 5, as well as MnSOD, after hydrogen peroxide (H2O2) treatment showed a significant improvement after pretreatment with 0.01% and 0.1% CJ extracts. Mice treated with 0.1% CJ extract showed significantly improved clinical parameters when compared to those of the EDE control and BSS groups. A significant decrease in the levels of inflammatory markers and intracellular ROS was observed in the 0.01% and 0.1% CJ extract groups. Camellia japonica extracts promoted antioxidative protein expression and suppressed apoptosis in HCE cells. Furthermore, CJ extracts improved clinical signs of dry eye and reduced oxidative stress and the expression of inflammatory markers, suggesting that eye drops containing CJ extract could be used as an adjunctive treatment for dry eye.

  19. Human eye-head gaze shifts preserve their accuracy and spatiotemporal trajectory profiles despite long-duration torque perturbations that assist or oppose head motion.

    Science.gov (United States)

    Boulanger, Mathieu; Galiana, Henrietta L; Guitton, Daniel

    2012-07-01

    Humans routinely use coordinated eye-head gaze saccades to rapidly and accurately redirect the line of sight (Land MF. Vis Neurosci 26: 51-62, 2009). With a fixed body, the gaze control system combines visual, vestibular, and neck proprioceptive sensory information and coordinates two moving platforms, the eyes and head. Classic engineering tools have investigated the structure of motor systems by testing their ability to compensate for perturbations. When a reaching movement of the hand is subjected to an unexpected force field of random direction and strength, the trajectory is deviated and its final position is inaccurate. Here, we found that the gaze control system behaves differently. We perturbed horizontal gaze shifts with long-duration torques applied to the head that unpredictably either assisted or opposed head motion and very significantly altered the intended head trajectory. We found, as others have with brief head perturbations, that gaze accuracy was preserved. Unexpectedly, we found also that the eye compensated well--with saccadic and rollback movements--for long-duration head perturbations such that resulting gaze trajectories remained close to that when the head was not perturbed. However, the ocular compensation was best when torques assisted, compared with opposed, head motion. If the vestibuloocular reflex (VOR) is suppressed during gaze shifts, as currently thought, what caused invariant gaze trajectories and accuracy, early eye-direction reversals, and asymmetric compensations? We propose three mechanisms: a gaze feedback loop that generates a gaze-position error signal; a vestibular-to-oculomotor signal that dissociates self-generated from passively imposed head motion; and a saturation element that limits orbital eye excursion.

  20. Xeno-Free and Defined Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells Functionally Integrate in a Large-Eyed Preclinical Model

    Directory of Open Access Journals (Sweden)

    Alvaro Plaza Reyes

    2016-01-01

    Full Text Available Human embryonic stem cell (hESC-derived retinal pigment epithelial (RPE cells could replace lost tissue in geographic atrophy (GA but efficacy has yet to be demonstrated in a large-eyed model. Also, production of hESC-RPE has not yet been achieved in a xeno-free and defined manner, which is critical for clinical compliance and reduced immunogenicity. Here we describe an effective differentiation methodology using human laminin-521 matrix with xeno-free and defined medium. Differentiated cells exhibited characteristics of native RPE including morphology, pigmentation, marker expression, monolayer integrity, and polarization together with phagocytic activity. Furthermore, we established a large-eyed GA model that allowed in vivo imaging of hESC-RPE and host retina. Cells transplanted in suspension showed long-term integration and formed polarized monolayers exhibiting phagocytic and photoreceptor rescue capacity. We have developed a xeno-free and defined hESC-RPE differentiation method and present evidence of functional integration of clinically compliant hESC-RPE in a large-eyed disease model.

  1. Imaging the Aqueous Humor Outflow Pathway in Human Eyes by Three-dimensional Micro-computed Tomography (3D micro-CT)

    Energy Technology Data Exchange (ETDEWEB)

    C Hann; M Bentley; A Vercnocke; E Ritman; M Fautsch

    2011-12-31

    The site of outflow resistance leading to elevated intraocular pressure in primary open-angle glaucoma is believed to be located in the region of Schlemm's canal inner wall endothelium, its basement membrane and the adjacent juxtacanalicular tissue. Evidence also suggests collector channels and intrascleral vessels may have a role in intraocular pressure in both normal and glaucoma eyes. Traditional imaging modalities limit the ability to view both proximal and distal portions of the trabecular outflow pathway as a single unit. In this study, we examined the effectiveness of three-dimensional micro-computed tomography (3D micro-CT) as a potential method to view the trabecular outflow pathway. Two normal human eyes were used: one immersion fixed in 4% paraformaldehyde and one with anterior chamber perfusion at 10 mmHg followed by perfusion fixation in 4% paraformaldehyde/2% glutaraldehyde. Both eyes were postfixed in 1% osmium tetroxide and scanned with 3D micro-CT at 2 {mu}m or 5 {mu}m voxel resolution. In the immersion fixed eye, 24 collector channels were identified with an average orifice size of 27.5 {+-} 5 {mu}m. In comparison, the perfusion fixed eye had 29 collector channels with a mean orifice size of 40.5 {+-} 13 {mu}m. Collector channels were not evenly dispersed around the circumference of the eye. There was no significant difference in the length of Schlemm's canal in the immersed versus the perfused eye (33.2 versus 35.1 mm). Structures, locations and size measurements identified by 3D micro-CT were confirmed by correlative light microscopy. These findings confirm 3D micro-CT can be used effectively for the non-invasive examination of the trabecular meshwork, Schlemm's canal, collector channels and intrascleral vasculature that comprise the distal outflow pathway. This imaging modality will be useful for non-invasive study of the role of the trabecular outflow pathway as a whole unit.

  2. Small-Angle Fibre Diffraction Studies of Cornela Matrix Structure: A Depth-Profiled Investigation of the Human Eye-Bank Cornea

    Energy Technology Data Exchange (ETDEWEB)

    Quantock,A.; Boote, C.; Young, R.; Hayes, S.; Tanioka, H.; Kawasaki, S.; Ohta, N.; Lida, T.; Yagi, N.; et al.

    2007-01-01

    In the cornea of the eye light transmission is facilitated by the regular arrangement and uniform diameter of collagen fibrils that constitute the bulk of the extracellular corneal matrix. Matrix architecture, in turn, is believed to be governed by interactions between collagen fibrils and proteoglycan molecules modified with sulfated glycosaminoglycan side chains. Here, we outline the contribution made by small-angle X-ray scattering studies of the cornea in understanding the role of sulfated glycosaminoglycans in the control of collagen architecture in cornea, and present new depth-profiled microbeam data from swollen human eye-bank corneas that indicate no significant change in collagen fibril diameter throughout the tissue, but a lower collagen interfibrillar spacing in the anterior-most stromal regions compared with the ultrastructure of the deeper cornea.

  3. A 1.5-Mb contig within the cat eye syndrome critical region at human chromosome 22q11.2.

    Science.gov (United States)

    Johnson, A; Minoshima, S; Asakawa, S; Shimizu, N; Shizuya, H; Roe, B A; McDermid, H E

    1999-04-15

    We have constructed a 1.5-Mb contig spanning the distal half of the critical region for cat eye syndrome on human chromosome 22 from D22S543 to D22S181. The contig consists of 20 P1 artificial chromosome (PAC) clones and 11 bacterial artificial chromosome (BAC) clones screened from 2 BAC and 2 PAC libraries. Continuous overlap between the clones was confirmed using vectorette PCR and riboprobes. Despite the instability of this region in a previous YAC contig, only 1 BAC showed a minor instability and then in only one isolation. This contig is now providing the basis for genomic sequencing and gene identification in the cat eye syndrome critical region. Copyright 1999 Academic Press.

  4. Red Eye

    Science.gov (United States)

    ... AskMayoExpert. Conjunctivitis. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2014. Jan. 11, 2018 Original article: http://www.mayoclinic.org/symptoms/red-eye/basics/definition/SYM-20050748 . Mayo Clinic Footer Legal Conditions and ...

  5. Rosmarinic Acid Potentiates Pentobarbital-Induced Sleep Behaviors and Non-Rapid Eye Movement (NREM) Sleep through the Activation of GABAA-ergic Systems.

    Science.gov (United States)

    Kwon, Yeong Ok; Hong, Jin Tae; Oh, Ki-Wan

    2017-03-01

    It has been known that RA, one of major constituents of Perilla frutescens which has been used as a traditional folk remedy for sedation in oriental countries, shows the anxiolytic-like and sedative effects. This study was performed to know whether RA may enhance pentobarbital-induced sleep through γ-aminobutyric acid (GABA)A-ergic systems in rodents. RA (0.5, 1.0 and 2.0 mg/ kg, p.o.) reduced the locomotor activity in mice. RA decreased sleep latency and increased the total sleep time in pentobarbital (42 mg/kg, i.p.)-induced sleeping mice. RA also increased sleeping time and number of falling sleep mice after treatment with sub-hypnotic pentobarbital (28 mg/kg, i.p.). In electroencephalogram (EEG) recording, RA (2.0 mg/kg) not only decreased the counts of sleep/wake cycles and REM sleep, but also increased the total and NREM sleep in rats. The power density of NREM sleep showed the increase in δ-waves and the decrease in α-waves. On the other hand, RA (0.1, 1.0 and 10 μg/ml) increased intracellular Cl- influx in the primary cultured hypothalamic cells of rats. RA (p.o.) increased the protein expression of glutamic acid decarboxylase (GAD65/67) and GABAA receptors subunits except β1 subunit. In conclusion, RA augmented pentobarbital-induced sleeping behaviors through GABAA-ergic transmission. Thus, it is suggested that RA may be useful for the treatment of insomnia.

  6. Lack of delta waves and sleep disturbances during non-rapid eye movement sleep in mice lacking alpha1G-subunit of T-type calcium channels.

    Science.gov (United States)

    Lee, Jungryun; Kim, Daesoo; Shin, Hee-Sup

    2004-12-28

    T-type calcium channels have been implicated as a pacemaker for brain rhythms during sleep but their contribution to behavioral states of sleep has been relatively uncertain. Here, we found that mice lacking alpha1(G) T-type Ca(2+) channels showed a loss of the thalamic delta (1-4 Hz) waves and a reduction of sleep spindles (7-14 Hz), whereas slow (sleep. Analysis of sleep disturbances, as defined by the occurrence of brief awakening (BA) episodes during NREM sleep, revealed that mutant mice exhibited a higher incidence of BAs of >16 sec compared with the wild-type, whereas no difference was seen in BAs of sleep spindles from cortically generated slow waves. These results also suggest that the alpha1(G)-subunit of T-type calcium channels plays a critical role in the genesis of thalamocortical oscillations and contributes to the modulation of sleep states and the transition between NREM sleep and wake states.

  7. Lack of delta waves and sleep disturbances during non-rapid eye movement sleep in mice lacking α1G-subunit of T-type calcium channels

    OpenAIRE

    Lee, Jungryun; Kim, Daesoo; Shin, Hee-Sup

    2004-01-01

    T-type calcium channels have been implicated as a pacemaker for brain rhythms during sleep but their contribution to behavioral states of sleep has been relatively uncertain. Here, we found that mice lacking α1G T-type Ca2+ channels showed a loss of the thalamic delta (1–4 Hz) waves and a reduction of sleep spindles (7–14 Hz), whereas slow (16 sec compared with the wild-type, whereas no difference was seen in BAs of

  8. Effects of social stimuli on sleep in mice : non-rapid-eye-movement (NREM) sleep is promoted by aggressive interaction but not by sexual interaction

    NARCIS (Netherlands)

    Meerlo, Peter; Turek, Fred W.

    2001-01-01

    Sleep is generally considered to be a process of recovery from prior wakefulness. In addition to being affected by the duration of the waking period, sleep architecture and sleep EEG also depend on the quality of wakefulness. In the present experiment, we examined how sleep is affected by different

  9. Lack of delta waves and sleep disturbances during non-rapid eye movement sleep in mice lacking α1G-subunit of T-type calcium channels

    Science.gov (United States)

    Lee, Jungryun; Kim, Daesoo; Shin, Hee-Sup

    2004-01-01

    T-type calcium channels have been implicated as a pacemaker for brain rhythms during sleep but their contribution to behavioral states of sleep has been relatively uncertain. Here, we found that mice lacking α1G T-type Ca2+ channels showed a loss of the thalamic delta (1–4 Hz) waves and a reduction of sleep spindles (7–14 Hz), whereas slow (sleep. Analysis of sleep disturbances, as defined by the occurrence of brief awakening (BA) episodes during NREM sleep, revealed that mutant mice exhibited a higher incidence of BAs of >16 sec compared with the wild-type, whereas no difference was seen in BAs of sleep spindles from cortically generated slow waves. These results also suggest that the α1G-subunit of T-type calcium channels plays a critical role in the genesis of thalamocortical oscillations and contributes to the modulation of sleep states and the transition between NREM sleep and wake states. PMID:15601764

  10. 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? ...

  11. Using the human eye to image space radiation or the history and status of the light flash phenomena

    Science.gov (United States)

    Fuglesang, C.

    2007-10-01

    About 80% of people who travel in space experience sudden phosphenes, commonly called light flashes (LF). Although the detailed physiological process is still not known, the LFs are caused by particles in the cosmic radiation field. Indeed, by counting LFs one can even make a crude image of the radiation environment around the Earth. Studies on the space station Mir with the SilEye experiment correlated LFs with charged particles traversing the eye. It was found that a nucleus in the radiation environment has roughly a 1% probability of causing a light flash, whereas the proton's probability is almost three orders of magnitude less. As a function of linear energy transfer (LET), the probability increased with ionization above 10 keV/μm, reaching about 5% at 50 keV/μm. The investigations are continuing on the International Space Station (ISS) with the Alteino/SileEye-3 detector, which is also a precursor to the large Anomalous Long Term Effects on Astronauts (ALTEA) facility. These detectors are also measuring—imaging—the radiation environment inside the ISS, which will be compared to Geant4 simulations from the DESIRE project. To further the understanding of the LF phenomena, a survey among current NASA and ESA astronauts was recently conducted. The LFs are predominantly noticed before sleep and some respondents even thought it disturbed their sleep. The LFs appear white, have elongated shapes, and most interestingly, often come with a sense of motion. Comparing the shapes quoted from space observations with ground experiments done by researchers in the 1970s, it seems likely that some 5-10% of the LFs in space are due to Cherenkov light in the eye. However, the majority is most likely caused by some direct interaction in the retina.

  12. 21 CFR 886.3200 - Artificial eye.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Artificial eye. 886.3200 Section 886.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3200 Artificial eye. (a) Identification. An artificial eye is a...

  13. Immediate Effects of 3% Diquafosol and 0.1% Hyaluronic Acid Ophthalmic Solution on Tear Break-Up Time in Normal Human Eyes.

    Science.gov (United States)

    Nam, Ki Tae; Ahn, So Min; Eom, Youngsub; Kim, Hyo Myung; Song, Jong Suk

    2015-12-01

    The purpose of this study was to evaluate the immediate effect of 3% diquafosol ophthalmic solution on tear break-up time (TBUT) in normal human eyes, and to compare it with that of saline and 0.1% hyaluronate ophthalmic solution. Cross sectional comparative study in the first study, 10 healthy volunteers underwent topical application of 2 different ophthalmic solutions in each eye. Saline was randomly applied to one eye and 3% diquafosol ophthalmic solution was added to the fellow eye. TBUT was measured and video recorded before application and at 5, 10, 15, and 20 min after. The TBUT in each eye was compared at each time point with regard to the 2 different ophthalmic solutions. In the second study, another 10 healthy volunteers were included. The same methods were used to compare the immediate effects of 0.1% hyaluronate and 3% diquafosol ophthalmic solution application on TBUT. In the first study, topical instillation of saline did not increase TBUT. However, 3% diquafosol significantly increased TBUT for up to 15 min after application. At every time point, the TBUT increased more significantly from baseline in the diquafosol group than it did in the saline group. In the second study, 0.1% hyaluronate increased TBUT for up to 5 min after application, while 3% diquafosol increased TBUT for up to 15 min. Although the TBUT changes after 5 min were not significantly different between the 2 groups, the TBUT changes at 10, 15, and 20 min were significantly greater in the 3% diquafosol group than they were in the 0.1% hyaluronic acid group (+1.58 ± 0.82 vs. +0.53 ± 1.36 at 10 min, +0.67 ± 0.91 vs. -0.04 ± 1.29 at 15 min, and -0.06 ± 0.96 vs. -0.59 ± 0.90, diquafosol group vs. hyaluronic acid group). One drop of 3% diquafosol increased TBUT for up to 15 min after application. The immediate effect of 3% diquafosol on TBUT was greater than that of saline and even that of 1% hyaluronate ophthalmic solution.

  14. Proposal, verification and comparison of three computer image analysis methods for detection and evaluation of colour glaucomatous changes within the optic disc of a human eye retina

    Science.gov (United States)

    Pluhacek, Frantisek; Pospisil, Jaroslav

    2005-04-01

    The typical symptom of the human eye glaucoma is a rise and a progression of the bright area (named pallor area) within the retina blind spot. The image analysis manner proposed by the authors detects and suitably numerically describes the relative size of the representative pallor area in the colour digital image of the retina obtained by a suitable fundus camera connected with the computer. Three new different computer image analysis statistical methods for experimental diagnostic evaluation of the obtained characteristic data are proposed in this article: the quantile curves method, the neural net method and the probability density curves method. The quantile curves method is based on the graphical comparison of a relative representative pallor area size with its determined normal value. The neural net and probability density curves methods can automatically and objectively classify the investigated eyes in exactly defined glaucoma risk classes and diagnosed glaucoma with the rated probabilities of incorrect diagnosis determination. All mentioned methods are verified and mutually compared by their application to the large statistical sets of human retina images of various healthy and glaucomatous subjects.

  15. Eye trauma

    African Journals Online (AJOL)

    2011-02-02

    Feb 2, 2011 ... Industrial workers should be protected by safety glasses but injuries occur nonetheless. Eye trauma is frequent in homes, farms and backyards where safety glasses are not available. Angle-grinders, metal beating, hammering, fence mending, herding animals, forestry, fire fighting and cutting sugar cane ...

  16. Your Eyes

    Science.gov (United States)

    ... OK if you ask to see their liver! Big as a Ping Pong Ball The eye is about as big as a ping-pong ball and sits in ... of sight! Reviewed by: Jonathan H. Salvin, MD Date reviewed: February 2015 More on this topic for: ...

  17. Eye trauma

    African Journals Online (AJOL)

    2011-02-02

    Feb 2, 2011 ... Stain cornea with fluorescein. It is advisable to examine the eye as soon as possible since a delay will invariably lead to lid swelling, making the examination far more difficult. This can be overcome using cotton tips to retract the eyelids, or lid retractors can be made from bent paper clips (Illustration 1).

  18. Ocular surface area and human eye blink frequency during VDU work: the effect of monitor position and task.

    Science.gov (United States)

    Nielsen, Pernille Kofoed; Søgaard, Karen; Skotte, Jørgen; Wolkoff, Peder

    2008-05-01

    The purpose of this study was to investigate how the ocular surface area (OSA) and the eye blink frequency (BF) are affected by a high versus a low-monitor position during visual display unit (VDU) work with varying cognitive demands. In a balanced randomized (2 x 2) design ten healthy subjects (five males, five females) completed two different tasks on the VDU in a simulated office environment (23 degrees C and 30-35% relative humidity); an active task with demands on vision and hand-eye coordination, and a passive task. Two monitor positions were used: high (the monitors' upper edge at the same height as the subjects' eyes) and low (lowered by 25 degrees and perpendicular to gaze angle). Each task lasted 10 min. An OSA-proxy was measured from video recordings, and BF was sampled by electrooculography. The effect of lowering the gaze angle by 25 degrees decreased the OSA-proxy significantly (P < 0.01) during the active task, indicating that a low position of the monitor may be preferable even though the BF also decreased. Overall, the OSA-proxy was 6% higher during the active task compared to the passive while BF during the active task was 69% lower than during the passive task. The low BF during the active task was succeded by a burst with high BF after cessation of the active task, indicating a compensatory blinking process. This stresses that interchange of work tasks with different cognitive load is as important as the monitor position in the prevention of visual and musculoskeletal disorders.

  19. Cerebral O2 metabolism and cerebral blood flow in humans during deep and rapid-eye-movement sleep

    DEFF Research Database (Denmark)

    Madsen, P L; Schmidt, J F; Wildschiødtz, Gordon

    1991-01-01

    It could be expected that the various stages of sleep were reflected in variation of the overall level of cerebral activity and thereby in the magnitude of cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF). The elusive nature of sleep imposes major methodological restrictions...... on examination of this question. We have now measured CBF and CMRO2 in young healthy volunteers using the Kety-Schmidt technique with 133Xe as the inert gas. Measurements were performed during wakefulness, deep sleep (stage 3/4), and rapid-eye-movement (REM) sleep as verified by standard polysomnography...

  20. Conjunctivitis (Pink Eye)

    Science.gov (United States)

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

  1. About the Eye

    Medline Plus

    Full Text Available ... NEI for Kids > About the Eye All About Vision About the Eye Ask a Scientist Video Series ... Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun ...

  2. 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 ...

  3. About the Eye

    Medline Plus

    Full Text Available ... USAJobs Home > NEI for Kids > About the Eye All About Vision About the Eye Ask a Scientist Video ... Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More Information ...

  4. About the Eye

    Medline Plus

    Full Text Available ... USAJobs Home > NEI for Kids > About the Eye All About Vision About the Eye Ask a Scientist ... Links to More Information Optical Illusions Printables About the Eye Your eyes are made up of many ...

  5. 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 ...

  6. Diabetic Eye Disease

    Science.gov (United States)

    ... Disease, & Other Dental Problems Diabetes & Sexual & Urologic Problems Diabetic Eye Disease What is diabetic eye disease? Diabetic eye disease is a group ... eye diseases that can threaten your sight are Diabetic retinopathy The retina is the inner lining at ...

  7. 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- ...

  8. Why Do Eyes Water?

    Science.gov (United States)

    ... for Educators Search English Español Why Do Eyes Water? KidsHealth / For Kids / Why Do Eyes Water? What's ... coming out of your nose. Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  9. Eye Movement Disorders

    Science.gov (United States)

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

  10. Cortical dynamics during the preparation of antisaccadic and prosaccadic eye movements in humans in a gap paradigm.

    Directory of Open Access Journals (Sweden)

    Isabel Cordones

    Full Text Available To compare the cortical dynamics of different oculomotor tasks, EEG and eye movements were recorded in 21 volunteers. Using a comprehensive approach, subjects were asked to perform saccadic tasks, which included a saccadic eye movement to a peripheral target (prosaccadic, a movement to the opposite side (antisaccadic, or maintain the gaze fixed (no-go. In mixed trials, prosaccadic, antisaccadic and no-go tasks were indicated by a color square (S1 present for 1900-2500 ms (instructive period. S1 disappeared for 370 ms (gap and a black dot at 8 deg at right or left indicated the beginning of the task. Reaction times, amplitude of eye movements and number of errors were greatest in antisaccadic tasks, suggesting a greater difficulty. The EEG showed a contingent negativity variation (CNV that increased progressively along the instructive period and suddenly during the gap: higher in antisaccadic, followed by prosaccadic and no-go tasks. Principal component analysis (PCA disentangled fronto-central and occipital CNV-related and fronto-central gap-related components. The instructive period was characterized by fronto-central and occipital beta desynchronization (ERD higher in antisaccadic than in no-go and parieto-occipital alpha synchronization higher in no-go than in antisaccadic tasks. During the gap, parieto-occipital beta and alpha ERD were higher in antisaccadic compared to no-go. The gap was further characterized by a fronto-central increase of inter-trial coherence in theta: highest during antisaccadic, followed by prosaccadic and no-go tasks. This phase locking in theta was also accompanied by theta ERS, which was significantly higher in antisaccadic than in the other two tasks. In PCA of spectral power two main components had dynamics similar to those extracted from voltage data, suggesting cross-frequency coupling. These results suggest that the more difficult saccadic tasks are associated with top-down control mediated by frontal cortex

  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. Fundamental Evaluation of Adaptation and Human Capabilities in a Condition Using a System to Give a User an Artificial Oculomotor Function to Control Directions of Both Eyes Independently

    Directory of Open Access Journals (Sweden)

    Fumio Mizuno

    2011-10-01

    Full Text Available To investigate flexible adaptation of visual system, we developed a system to provide a user an artificial oculomotor function to control directions of both eyes. The system named “Virtual Chameleon” consists of two CCD cameras independently controlled and a head-mounted display. The user can control each tracking directions of two cameras with sensors set to both hands so that the user can get independent arbitrary view fields for both eyes. We performed fundamental experiments to evaluate capability to evaluate adaptation to use of Virtual Chameleon and effects on the user's capabilities. Eleven healthy volunteers with normal and corrected-to-normal vision participated in the experiments. The experiments were tests to find out each position of targets put in both side of a subject. In the experiments, a condition using Virtual Chameleon and a condition without it was adopted. We obtained accuracy rates and time intervals to find out target positions as experimental results. The experiments showed all of volunteers became able to actively control independent visual axes and correctly understood two different views by using Virtual Chameleon, even though two independent view fields yielded binocular rivalry to volunteers and binocular rivalry reduced human capabilities compared to cases without Virtual Chameleon.

  13. Preventing Eye Injuries

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Eye Injuries Sections Preventing Eye Injuries Recognizing and Treating Eye ... Five Steps to Safer Champagne Celebrations Preventing Eye Injuries Leer en Español: Lesiones de los Ojos Reviewed ...

  14. Trends and implications for achieving VISION 2020 human resources for eye health targets in 16 countries of sub-Saharan Africa by the year 2020

    Science.gov (United States)

    2014-01-01

    Background Development of human resources for eye health (HReH) is a major global eye health strategy to reduce the prevalence of avoidable visual impairment by the year 2020. Building on our previous analysis of current progress towards key HReH indicators and cataract surgery rates (CSRs), we predicted future indicator achievement among 16 countries of sub-Saharan Africa by 2020. Methods Surgical and HReH data were collected from national eye care programme coordinators on six practitioner cadres: ophthalmologists, cataract surgeons, ophthalmic clinical officers, ophthalmic nurses, optometrists and ‘mid-level refractionists’ and combined them with publicly available population data to calculate practitioner-to-population ratios and CSRs. Data on workforce entry and exit (2008 to 2010) was used to project practitioner population and CSR growth between 2011 and 2020 in relation to projected growth in the general population. Associations between indicator progress and the presence of a non-physician cataract surgeon cadre were also explored using Wilcoxon rank sum tests and Spearman rank correlations. Results In our 16-country sample, practitioner per million population ratios are predicted to increase slightly for surgeons (ophthalmologists/cataract surgeons, from 3.1 in 2011 to 3.4 in 2020) and ophthalmic nurses/clinical officers (5.8 to 6.8) but remain low for refractionists (including optometrists, at 3.6 in 2011 and 2020). Among countries that have not already achieved target indicators, however, practitioner growth will be insufficient for any additional countries to reach the surgeon and refractionist targets by year 2020. Without further strategy change and investment, even after 2020, surgeon growth is only expected to sufficiently outpace general population growth to reach the target in one country. For nurses, two additional countries will achieve the target while one will fall below it. In 2011, high surgeon practitioner ratios were associated with

  15. The gene for death agonist BID maps to the region of human 22q11.2 duplicated in cat eye syndrome chromosomes and to mouse chromosome 6.

    Science.gov (United States)

    Footz, T K; Birren, B; Minoshima, S; Asakawa, S; Shimizu, N; Riazi, M A; McDermid, H E

    1998-08-01

    Cat eye syndrome (CES) is associated with a duplication of a segment of human chromosome 22q11.2. Only one gene, ATP6E, has been previously mapped to this duplicated region. We now report the mapping of the human homologue of the apoptotic agonist Bid to human chromosome 22 near locus D22S57 in the CES region. Dosage analysis demonstrated that BID is located just distal to the CES region critical for the majority of malformations associated with the syndrome (CESCR), as previously defined by a single patient with an unusual supernumerary chromosome. However, BID remains a good candidate for involvement in CES-related mental impairment, and its overexpression may subtly add to the phenotype of CES patients. Our mapping of murine Bid confirms that the synteny of the CESCR and the 22q11 deletion syndrome critical region immediately telomeric on human chromosome 22 is not conserved in mice. Bid and adjacent gene Atp6e were found to map to mousechromosome 6, while the region homologous to the DGSCR is known to map to mouse chromosome 16. Copyright 1998 Academic Press.

  16. Bona fide colour: DNA prediction of human eye and hair colour from ancient and contemporary skeletal remains

    NARCIS (Netherlands)

    J. Draus-Barini (Jolanta); S. Walsh (Susan); E. Pośpiech (Ewelina); T. Kupiec (Tomasz); H. Głab (Henryk); W. Branicki (Wojciech); M.H. Kayser (Manfred)

    2013-01-01

    textabstractBackground: DNA analysis of ancient skeletal remains is invaluable in evolutionary biology for exploring the history of species, including humans. Contemporary human bones and teeth, however, are relevant in forensic DNA analyses that deal with the identification of perpetrators, missing

  17. Age-related changes in local water and protein content of human eye lenses measured by Raman microspectroscopy

    NARCIS (Netherlands)

    Siebinga, I.; Siebinga, I.; Vrensen, G.F.J.M.; de Mul, F.F.M.; Greve, Jan

    1991-01-01

    The Raman microspectroscopic method was used to determine the local water and protein content in human lenses. In 18 lenses of varying age position-defined water/protein content measurements were carried out along the visual and the equatorial axis. A main characteristic of the human lens is its

  18. Molecular Inflammation in the Contralateral Eye After Cataract Surgery in the First Eye.

    Science.gov (United States)

    Zhu, Xiang-Jia; Wolff, Don; Zhang, Ke-Ke; He, Wen-Wen; Sun, Xing-Huai; Lu, Yi; Zhou, Peng

    2015-08-01

    The purpose of this study was to assess the inflammatory status of the aqueous humor in the fellow eye after uneventful cataract surgery in the first eye. At the screening stage, aqueous humor samples from 15 first-eye and 15 second-eye cataract patients were collected just before cataract surgery and assayed using human cytokine antibody array. Screened cytokines were then verified using a suspension array system with aqueous humor samples obtained from 35 first-eye and 36 second-eye cataract patients. The cytokine antibody array revealed that interleukin-1 receptor antagonist (Il-1ra) and macrophage inflammatory protein (MIP)-1a and MIP-1b were expressed at high levels in first-eye patients and were lower in second-eye patients, whereas opposite trends were found for monocyte chemoattractant protein 1 (MCP-1) and for regulated on activation, normal T expressed and secreted (RANTES) (all, P eye patients than in that of first-eye patients (P = 0.0067, Student's t-test). This study revealed that expression of MCP-1, a pain-related inflammatory chemokine, was significantly increased in aqueous humor in the contralateral eye after first-eye cataract surgery. This suggests there may be a sympathetic ophthalmic type uveitis in the contralateral eye after first-eye cataract surgery and that may help to explain why second-eye phacoemulsification is often more painful. (ClinicalTrials.gov number, NCT01824927.)

  19. Do the eyes scan dream images during rapid eye movement sleep? Evidence from the rapid eye movement sleep behaviour disorder model.

    Science.gov (United States)

    Leclair-Visonneau, Laurène; Oudiette, Delphine; Gaymard, Bertrand; Leu-Semenescu, Smaranda; Arnulf, Isabelle

    2010-06-01

    Rapid eye movements and complex visual dreams are salient features of human rapid eye movement sleep. However, it remains to be elucidated whether the eyes scan dream images, despite studies that have retrospectively compared the direction of rapid eye movements to the dream recall recorded after having awakened the sleeper. We used the model of rapid eye movement sleep behaviour disorder (when patients enact their dreams by persistence of muscle tone) to determine directly whether the eyes move in the same directions as the head and limbs. In 56 patients with rapid eye movement sleep behaviour disorder and 17 healthy matched controls, the eye movements were monitored by electrooculography in four (right, left, up and down) directions, calibrated with a target and synchronized with video and sleep monitoring. The rapid eye movement sleep behaviour disorder-associated behaviours occurred 2.1 times more frequently during rapid eye movement sleep with than without rapid eye movements, and more often during or after rapid eye movements than before. Rapid eye movement density, index and complexity were similar in patients with rapid eye movement sleep behaviour disorder and controls. When rapid eye movements accompanied goal-oriented motor behaviour during rapid eye movement sleep behaviour disorder (e.g. grabbing a fictive object, hand greetings, climbing a ladder), which happened in 19 sequences, 82% were directed towards the action of the patient (same plane and direction). When restricted to the determinant rapid eye movements, the concordance increased to 90%. Rapid eye movements were absent in 38-42% of behaviours. This directional coherence between limbs, head and eye movements during rapid eye movement sleep behaviour disorder suggests that, when present, rapid eye movements imitate the scanning of the dream scene. Since the rapid eye movements are similar in subjects with and without rapid eye movement sleep behaviour disorder, this concordance can be extended

  20. Questions Students Ask: The Red-Eye Effect.

    Science.gov (United States)

    Physics Teacher, 1985

    1985-01-01

    Addresses the question of why a dog's eyes appear red and glow when a flash photograph is taken. Conditions for the red-eye effect, light paths involved, structure of the eye, and typical cameras and lenses are discussed. Also notes differences between the eyes of nocturnal animals and humans. (JN)

  1. Optimizing viewing procedures of breast tomosynthesis image volumes using eye tracking combined with a free response human observer study

    Science.gov (United States)

    Lång, Kristina; Zackrisson, Sophia; Holmqvist, Kenneth; Nystrom, Marcus; Andersson, Ingvar; Förnvik, Daniel; Tingberg, Anders; Timberg, Pontus

    2011-03-01

    The purpose of this study was to evaluate four different viewing procedures as part of improving viewing conditions of breast tomosynthesis (BT) image volumes. The procedures consisted of free scroll volume browsing, and a combination of initial cine loops at three different frame rates (9, 14 and 25 fps) terminated upon request followed by free scroll volume browsing. Fifty-five normal BT image volumes in MLO view were collected. In these, simulated lesions (20 masses and 20 clusters of microcalcifications) were randomly inserted, creating four unique image sets for each procedure. Four readers interpreted the cases in a random order. Their task was to locate a lesion, mark and assign a five level confidence scale. The diagnostic accuracy was analyzed using Jackknife Free Receiver Operating Characteristics (JAFROC). Time efficiency and visual search behavior were also investigated using eye tracking. The results indicate that there was no statistically significant difference in JAFROC FOM between the different viewing procedures, however the medium cine loop speed seemed to be the preferred viewing procedure in terms of total analyze time and dwell time.

  2. Age-related changes in local water and protein content of human eye lenses measured by Raman microspectroscopy

    OpenAIRE

    Siebinga, I.; Siebinga, I.; Vrensen, G.F.J.M.; de Mul, F.F.M.; Greve, Jan

    1991-01-01

    The Raman microspectroscopic method was used to determine the local water and protein content in human lenses. In 18 lenses of varying age position-defined water/protein content measurements were carried out along the visual and the equatorial axis. A main characteristic of the human lens is its constant and relatively low protein content. In addition this constant nuclear value is reached within a short distance from the capsular surface. For statistical analysis of age-related changes the d...

  3. Modelling the impact of blood flow on the temperature distribution in the human eye and the orbit: fixed heat transfer coefficients versus the Pennes bioheat model versus discrete blood vessels

    Science.gov (United States)

    Flyckt, V. M. M.; Raaymakers, B. W.; Lagendijk, J. J. W.

    2006-10-01

    Prediction of the temperature distribution in the eye depends on how the impact of the blood flow is taken into account. Three methods will be compared: a simplified eye anatomy that applies a single heat transfer coefficient to describe all heat transport mechanisms between the sclera and the body core, a detailed eye anatomy in which the blood flow is accounted for either by the bioheat approach, or by including the discrete vasculature in the eye and the orbit. The comparison is done both for rabbit and human anatomies, normo-thermally and when exposed to homogeneous power densities. The first simplified model predicts much higher temperatures than the latter two. It was shown that the eye is very hard to heat when taking physiological perfusion correctly into account. It was concluded that the heat transfer coefficient describing the heat transport from the sclera to the body core reported in the literature for the first simplified model is too low. The bioheat approach is appropriate for a first-order approximation of the temperature distribution in the eye when exposed to a homogeneous power density, but the discrete vasculature down to 0.2 mm in diameter needs to be taken into account when the heterogeneity of the temperature distribution at a mm scale is of interest.

  4. Disruptive camouflage tricks the human eye: a study of detection times of two near-similar targets in natural backgrounds

    Science.gov (United States)

    Selj, Gorm K.

    2015-10-01

    Our understanding of camouflage, in military as well as in evolutionary perspectives, has been developing over the last 100 years. In that period of time several underlying principles have emerged. It has turned out in the recent decade that background pattern matching alone may not be sufficient to conceal targets because of the ubiquitous and revealing information contained by the edges of a target. In this paper we have studied one concealment strategy, the so-called disruptive coloration, further as it predicts that high contrast patches placed at the target's outline will impede detection, by creating false target edges when exposed to the observer. Such disruptive coloration is contra-intuitive as it may impede detection in spite of the fact that the patches themselves may be poorly concealed. In military environments the "disruptive approach" within camouflage has been textbook material for decades. Still, very little has been reported, supporting this idea, especially when it comes to the concealment of human targets in natural sceneries. We report here experimental evidence from a field study, containing detection data from 12 unique natural scenes (5 testing the disruptive effect, 7 as reference tests), with both human targets and human observers, showing that disruptively colored camouflage patches along a human's outline (its head) may increase detection time significantly as when compared to a similar (human) target concealed only with background matching. Hence, our results support the idea that disruptive coloration may impede detection and similarly that the best concealment is achieved when disruptive coloration is added to a target that matches the background (reasonably) well. This study raises important question to the current understanding of human vision and concealment as well as to any approach to describe the human visual system mathematically.

  5. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Eye Symptoms Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué ... Your Eyelid Nov 29, 2017 New Dry Eye Treatment is a Tear-Jerker Jul 21, 2017 Three ...

  6. 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 ...

  7. 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 ...

  8. What Is Dry Eye?

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    Full Text Available ... Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Eye Health Find an Ophthalmologist Academy Store Eye Health A- ... Get ophthalmologist-reviewed tips and information about eye health and preserving your vision. Privacy ... Choosing Wisely When It Comes to Eye Care, Part 5 Mar 19, 2013 Eye Makeup Safety ...

  9. What Is Dry Eye?

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    Full Text Available ... Health Find an Ophthalmologist Academy Store Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask ... Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? ...

  10. Arousal facilitates involuntary eye movements.

    Science.gov (United States)

    DiGirolamo, Gregory J; Patel, Neha; Blaukopf, Clare L

    2016-07-01

    Attention plays a critical role in action selection. However, the role of attention in eye movements is complicated as these movements can be either voluntary or involuntary, with, in some circumstances (antisaccades), these two actions competing with each other for execution. But attending to the location of an impending eye movement is only one facet of attention that may play a role in eye movement selection. In two experiments, we investigated the effect of arousal on voluntary eye movements (antisaccades) and involuntary eye movements (prosaccadic errors) in an antisaccade task. Arousal, as caused by brief loud sounds and indexed by changes in pupil diameter, had a facilitation effect on involuntary eye movements. Involuntary eye movements were both significantly more likely to be executed and significantly faster under arousal conditions (Experiments 1 and 2), and the influence of arousal had a specific time course (Experiment 2). Arousal, one form of attention, can produce significant costs for human movement selection as potent but unplanned actions are benefited more than planned ones.

  11. The immune privilege of the eye: human retinal pigment epithelial cells selectively modulate T-cell activation in vitro

    DEFF Research Database (Denmark)

    Kaestel, Charlotte G; Lovato, Paola; Ødum, Niels

    2005-01-01

    PURPOSE: To examine the effect of human retinal pigment epithelial (RPE) cells on phytohemagglutinin (PHA) activation of T cells. METHODS: Resting peripheral blood lymphocytes (PBLs) were stimulated with PHA with or without the presence of gamma-irradiated RPE cells. Proliferation and the cell...

  12. False positive reactivity of a substance P-antibody in the ectodermal/epithelial plug of the nose, ear, eye and perineum of the human and mouse fetuses.

    Science.gov (United States)

    Masumoto, Hiroshi; Katori, Yukio; Kawase, Tetsuaki; Cho, Baik Hwan; Murakami, Gen; Shibata, Shunichi; Matsubara, Akio

    2010-08-01

    Epithelial/ectodermal plug formation in the developing nose, ear, and eye regions is followed by canalization/recanalization mediated by cell death. However, the mechanism is not well understood. Recently, substance P (SP)-mediated cell death, rather than cell apoptosis, has been reported in neuronal and non-neuronal cells. Horizontal paraffin sections of 5 human fetuses at 15-16 weeks of gestation were used to examine the entire area of the nose, ear, eye and perineum with immunohistochemistry for SP and its receptor neurokinin-1 (NK-1), and protein gene product (PGP) 9.5 and S100 protein to identify whether the positive cells had neural origins. The deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) method was also conducted to identify apoptosis. Four SP antibodies were commercially obtained and compared the results. In addition, using the same antibodies for SP, those results were compared with fetal mouse heads (E14-17). Substance P immunoreactivity of one of the 4 antibodies (sc9758) was clearly found in the nasal plug, the epithelium of the anterior nasal cavity, the entire excretory tear duct, the marginal palpebral conjunctiva, the auditory meatal plug, the parotid duct, the external urethral orifice and, the preputial lamella along the future prepuce. Immunoreactivity was usually seen in enlarged round cells in humans. In fetal mouse heads, in spite of negative reaction in all these sites, the midline epithelial seam at the palate fusion and the oral epithelium especially at and near the tooth germ specifically reacted with the sc9758. Nevertheless, the other 3 antibodies did not react at any of those sites both in human and mouse fetuses. NK-1 receptor-positive cells were seen in the nose and meatal plugs and preputial lamella, but not in the tear duct. S100 protein, PGP 9.5, and TUNEL method all demonstrated negative reactivity at any sc9758-positive sites. Consequently, the present immunoreactivity of the sc9758

  13. The human homolog of insect-derived growth factor, CECR1, is a candidate gene for features of cat eye syndrome.

    Science.gov (United States)

    Riazi, M A; Brinkman-Mills, P; Nguyen, T; Pan, H; Phan, S; Ying, F; Roe, B A; Tochigi, J; Shimizu, Y; Minoshima, S; Shimizu, N; Buchwald, M; McDermid, H E

    2000-03-15

    Cat eye syndrome (CES) is a developmental disorder with multiple organ involvement, associated with the duplication of a 2-Mb region of 22q11.2. Using exon trapping and genomic sequence analysis, we have isolated and characterized a gene, CECR1, that maps to this critical region. The protein encoded by CECR1 is similar to previously identified novel growth factors: IDGF from Sarcophaga peregrina (flesh fly) and MDGF from Aplysia californica (sea hare). The CECR1 gene is alternatively spliced and expressed in numerous tissues, with most abundant expression in human adult heart, lung, lymphoblasts, and placenta as well as fetal lung, liver, and kidney. In situ hybridization of a human embryo shows specific expression in the outflow tract and atrium of the developing heart, the VII/VIII cranial nerve ganglion, and the notochord. The location of this gene in the CES critical region and its embryonic expression suggest that the overexpression of CECR1 may be responsible for at least some features of CES, particularly the heart defects. Copyright 2000 Academic Press.

  14. About the Eye

    Medline Plus

    Full Text Available ... Cool Eye Tricks Links to More Information Optical Illusions Printables About the Eye Your eyes are made ... of the macula, where your vision is sharpest. Optic nerve (OP-tic nurv) is the bundle of ...

  15. About the Eye

    Medline Plus

    Full Text Available ... and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and ... National Eye Health Education Program (NEHEP) Diabetic Eye Disease Education Program Glaucoma Education Program Low Vision Education ...

  16. 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 ...

  17. Dilating Eye Drops

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Dilating Eye Drops En Español Read in Chinese What are dilating eye drops? Dilating eye drops contain medication to enlarge ( ...

  18. 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 ...

  19. Eyes, Bulging (Proptosis)

    Science.gov (United States)

    ... Therapy for Kids With Rare Eye Disease (Video) Ocular Implant (Video) Glaucoma Additional Content Medical News Eyes, ... has other eye symptoms, such as dryness, increased tear formation, double vision, loss of vision, irritation, or ...

  20. What Is Dry Eye?

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    Full Text Available ... vision? May 27, 2017 Is stopping Restasis dangerous? Mar 06, 2017 Why are my eyes bloodshot when ... When It Comes to Eye Care, Part 5 Mar 19, 2013 Eye Makeup Safety Tips Sep 25, ...

  1. LASIK eye surgery

    Science.gov (United States)

    ... to correct a very nearsighted eye may prevent amblyopia (lazy eye). Your eyes must be healthy and ... any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should ...

  2. About the Eye

    Medline Plus

    Full Text Available ... and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of ... National Eye Health Education Program (NEHEP) Diabetic Eye Disease Education Program Glaucoma Education Program Low Vision Education ...

  3. 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. ...

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... also when your eyes do not make the right type of tears or tear film. How do ... information about eye health and preserving your vision. Privacy Policy Related New Dry Eye Treatment is a ...

  5. What Is Dry Eye?

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    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- ...

  6. What Is Dry Eye?

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    Full Text Available ... Get ophthalmologist-reviewed tips and information about eye health and preserving your vision. Privacy ... Choosing Wisely When It Comes to Eye Care, Part 5 Mar 19, 2013 Eye Makeup Safety ...

  7. Prediction of Severe Eye Injuries in Automobile Accidents: Static and Dynamic Rupture Pressure of the Eye

    OpenAIRE

    Kennedy, Eric A.; Voorhies, Katherine D.; Herring, Ian P.; Rath, Amber L.; Duma, Stefan M.

    2004-01-01

    The purpose of this paper is to determine the static and dynamic rupture pressures of 20 human and 20 porcine eyes. This study found the static test results show an average rupture pressure for porcine eyes of 1.00 ± 0.18 MPa while the average rupture pressure for human eyes was 0.36 ± 0.20 MPa. For dynamic loading, the average porcine rupture pressure was 1.64 ± 0.32 MPa, and the average rupture pressure for human eyes was 0.91 ± 0.29 MPa. Significant differences are found between average ru...

  8. 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 ...

  9. 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.

  10. Retinal and post-retinal contributions to the Quantum efficiency of the human eye revealed by electrical neuroimaging

    Directory of Open Access Journals (Sweden)

    Gibran eManasseh

    2013-11-01

    Full Text Available The retina is one of the best known quantum detectors with rods able to reliably respond to single photons. However, estimates on the number of photons eliciting conscious perception, based on signal detection theory, are systematically above these values after discounting by retinal losses. One possibility is that there is a trade-off between the limited motor resources available to living systems and the excellent reliability of the visual photoreceptors. On this view, the limits to sensory thresholds are not set by the individual reliability of the receptors within each sensory modality (as often assumed but rather by the limited central processing and motor resources available to process the constant inflow of sensory information. To investigate this issue, we reproduced the classical experiment from Hetch aimed to determine the sensory threshold in human vision. We combined a careful physical control of the stimulus parameters with high temporal/spatial resolution recordings of EEG signals and behavioral variables over a relatively large sample of subjects (12. Contrarily to the idea that the limits to visual sensitivity are fully set by the statistical fluctuations in photon absorption on retinal photoreceptors we observed that the state of ongoing neural oscillations before any photon impinges the retina helps to determine if the responses of photoreceptors have access to central conscious processing. Our results suggest that motivational and attentional off-retinal mechanisms play a major role in reducing the QE efficiency of the human visual system when compared to the efficiency of isolated retinal photoreceptors. Yet, this mechanism might subserve adaptive behavior by enhancing the overall multisensory efficiency of the whole system composed by diverse reliable sensory modalities.

  11. Lipid composition of the human eye: are red blood cells a good mirror of retinal and optic nerve fatty acids?

    Directory of Open Access Journals (Sweden)

    Niyazi Acar

    Full Text Available BACKGROUND: The assessment of blood lipids is very frequent in clinical research as it is assumed to reflect the lipid composition of peripheral tissues. Even well accepted such relationships have never been clearly established. This is particularly true in ophthalmology where the use of blood lipids has become very common following recent data linking lipid intake to ocular health and disease. In the present study, we wanted to determine in humans whether a lipidomic approach based on red blood cells could reveal associations between circulating and tissue lipid profiles. To check if the analytical sensitivity may be of importance in such analyses, we have used a double approach for lipidomics. METHODOLOGY AND PRINCIPAL FINDINGS: Red blood cells, retinas and optic nerves were collected from 9 human donors. The lipidomic analyses on tissues consisted in gas chromatography and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS. Gas chromatography did not reveal any relevant association between circulating and ocular fatty acids except for arachidonic acid whose circulating amounts were positively associated with its levels in the retina and in the optic nerve. In contrast, several significant associations emerged from LC-ESI-MS analyses. Particularly, lipid entities in red blood cells were positively or negatively associated with representative pools of retinal docosahexaenoic acid (DHA, retinal very-long chain polyunsaturated fatty acids (VLC-PUFA or optic nerve plasmalogens. CONCLUSIONS AND SIGNIFICANCE: LC-ESI-MS is more appropriate than gas chromatography for lipidomics on red blood cells, and further extrapolation to ocular lipids. The several individual lipid species we have identified are good candidates to represent circulating biomarkers of ocular lipids. However, further investigation is needed before considering them as indexes of disease risk and before using them in clinical studies on

  12. Lipid composition of the human eye: are red blood cells a good mirror of retinal and optic nerve fatty acids?

    Science.gov (United States)

    Acar, Niyazi; Berdeaux, Olivier; Grégoire, Stéphane; Cabaret, Stéphanie; Martine, Lucy; Gain, Philippe; Thuret, Gilles; Creuzot-Garcher, Catherine P; Bron, Alain M; Bretillon, Lionel

    2012-01-01

    The assessment of blood lipids is very frequent in clinical research as it is assumed to reflect the lipid composition of peripheral tissues. Even well accepted such relationships have never been clearly established. This is particularly true in ophthalmology where the use of blood lipids has become very common following recent data linking lipid intake to ocular health and disease. In the present study, we wanted to determine in humans whether a lipidomic approach based on red blood cells could reveal associations between circulating and tissue lipid profiles. To check if the analytical sensitivity may be of importance in such analyses, we have used a double approach for lipidomics. Red blood cells, retinas and optic nerves were collected from 9 human donors. The lipidomic analyses on tissues consisted in gas chromatography and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS). Gas chromatography did not reveal any relevant association between circulating and ocular fatty acids except for arachidonic acid whose circulating amounts were positively associated with its levels in the retina and in the optic nerve. In contrast, several significant associations emerged from LC-ESI-MS analyses. Particularly, lipid entities in red blood cells were positively or negatively associated with representative pools of retinal docosahexaenoic acid (DHA), retinal very-long chain polyunsaturated fatty acids (VLC-PUFA) or optic nerve plasmalogens. LC-ESI-MS is more appropriate than gas chromatography for lipidomics on red blood cells, and further extrapolation to ocular lipids. The several individual lipid species we have identified are good candidates to represent circulating biomarkers of ocular lipids. However, further investigation is needed before considering them as indexes of disease risk and before using them in clinical studies on optic nerve neuropathies or retinal diseases displaying photoreceptors degeneration.

  13. Interaction vs. observation: distinctive modes of social cognition in human brain and behavior? A combined fMRI and eye-tracking study.

    Science.gov (United States)

    Tylén, Kristian; Allen, Micah; Hunter, Bjørk K; Roepstorff, Andreas

    2012-01-01

    Human cognition has usually been approached on the level of individual minds and brains, but social interaction is a challenging case. Is it best thought of as a self-contained individual cognitive process aiming at an "understanding of the other," or should it rather be approached as an collective, inter-personal process where individual cognitive components interact on a moment-to-moment basis to form coupled dynamics? In a combined fMRI and eye-tracking study we directly contrasted these models of social cognition. We found that the perception of situations affording social contingent responsiveness (e.g., someone offering or showing you an object) elicited activations in regions of the right posterior temporal sulcus and yielded greater pupil dilation corresponding to a model of coupled dynamics (joint action). In contrast, the social-cognitive perception of someone "privately" manipulating an object elicited activation in medial prefrontal cortex, the right inferior frontal gyrus and right inferior parietal lobus, regions normally associated with Theory of Mind and with the mirror neuron system. Our findings support a distinction in social cognition between social observation and social interaction, and demonstrate that simple ostensive cues may shift participants' experience, behavior, and brain activity between these modes. The identification of a distinct, interactive mode has implications for research on social cognition, both in everyday life and in clinical conditions.

  14. Interaction versus Observation: distinctive modes of social cognition in human brain and behavior? A combined fMRI and eye-tracking study.

    Directory of Open Access Journals (Sweden)

    Kristian eTylen

    2012-12-01

    Full Text Available Human cognition has usually been approached on the level of individual minds and brains, but social interaction is a challenging case. Is it best thought of as a self-contained individual cognitive process aiming at an ‘understanding of the other’, or should it rather be approached as an collective, inter-personal process where individual cognitive components interact on a moment-to-moment basis to form coupled dynamics? In a combined fMRI and eye tracking study we directly contrasted these models of social cognition. We found that the perception of situations affording social contingent responsiveness (e.g. someone offering or showing you an object elicited activations in regions of the right posterior temporal sulcus and yielded greater pupil dilation corresponding to a model of coupled dynamics (joint action. In contrast, the social-cognitive perception of someone ‘privately’ manipulating an object elicited activation in medial prefrontal cortex, the right inferior frontal gyrus and right inferior parietal lobus, regions normally associated with Theory of Mind and with the mirror neuron system. Our findings support a distinction in social cognition between social observation and social interaction, and demonstrate that simple ostensive cues may shift participants’ experience, behavior and brain activity between these modes. The identification of a distinct, interactive mode has implications for research on social cognition, both in everyday life and in clinical conditions.

  15. High Permeability and Intercellular Space Widening With Brimonidine Tartrate Eye Drops in Cultured Stratified Human Corneal Epithelial Sheets.

    Science.gov (United States)

    Hashimoto, Yumi; Yokoo, Seiichi; Usui, Tomohiko; Tsubota, Yukiko; Yamagami, Satoru

    2018-02-01

    To investigate the toxicity of topical glaucoma medications using cultured stratified human corneal epithelial sheets (HCES). HCES were exposed for 30 minutes to the following glaucoma medications: 0.1% brimonidine with sodium chlorite as the preservative, 0.005% latanoprost with 0.02% benzalkonium chloride (BAC) as the preservative, and 0.5% timolol with 0.005% BAC as the preservative. Then, cell viability and barrier function were tested by the WST-1 assay and carboxyfluorescein permeability assay, respectively. After exposure to glaucoma medications, HCES were evaluated by hematoxylin and eosin staining, periodic acid-Schiff staining, scanning electron microscopy, and transmission electron microscopy. HCES exposed to brimonidine showed higher viability and better preservation of cell morphology and microvilli compared with cell sheets exposed to latanoprost or timolol. The carboxyfluorescein permeability assay demonstrated that the barrier function was preserved after HCES were exposed to timolol, but not after exposure to brimonidine or latanoprost. Transmission electron microscopy revealed widening of intercellular junctions with prominent deposits of glycogen or mucopolysaccharide (periodic acid-Schiff positive) after exposure of HCES to brimonidine. The toxicity of 0.1% brimonidine containing sodium chlorite for HCES was lower than that of ophthalmic preparations containing BAC. Reduction of the barrier function occurred after HCES were exposed to brimonidine because of widening of intercellular junctions.

  16. About the Eye

    Medline Plus

    Full Text Available ... the eye behind the iris that helps to focus light on the retina. It allows the eye to focus on both far and near objects. Iris is ... front of your eye. It helps your eye focus light so things look sharp and clear. Sclera ( ...

  17. About the Eye

    Medline Plus

    Full Text Available ... All About Vision About the Eye 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 ...

  18. Eye Injuries in Sports

    Science.gov (United States)

    ... very high risk. This includes boxing, wrestling, and martial arts.There are several types of common eye injuries in sports.Blunt trauma injuries. These occur when something or someone hits you in or around your eye. A black eye is bruising of your eye, eyelid, or ...

  19. Eye Movements in Reading as Rational Behavior

    Science.gov (United States)

    Bicknell, Klinton

    2011-01-01

    Moving one's eyes while reading is one of the most complex everyday tasks humans face. To perform efficiently, readers must make decisions about when and where to move their eyes every 200-300ms. Over the past decades, it has been demonstrated that these fine-grained decisions are influenced by a range of linguistic properties of the text, and…

  20. Recognizing and Treating Eye Injuries

    Science.gov (United States)

    ... Patient Stories Español Eye Health / Tips & Prevention Eye Injuries Sections Preventing Eye Injuries Recognizing and Treating Eye ... to Safer Champagne Celebrations Recognizing and Treating Eye Injuries Leer en Español: Reconociendo las Lesiones de los ...

  1. Visually guided eye growth in the squid.

    Science.gov (United States)

    Turnbull, Philip R K; Backhouse, Simon; Phillips, John R

    2015-09-21

    Eyes with refractive error have reduced visual acuity and are rarely found in the wild. Vertebrate eyes possess a visually guided emmetropisation process within the retina which detects the sign of defocus, and regulates eye growth to align the retina at the focal plane of the eye's optical components to avoid the development of refractive error, such as myopia, an increasing problem in humans. However, the vertebrate retina is complex, and it is not known which of the many classes of retinal neurons are involved. We investigated whether the camera-type eye of an invertebrate, the squid, displays visually guided emmetropisation, despite squid eyes having a simple photoreceptor-only retina. We exploited inherent longitudinal chromatic aberration (LCA) to create disparate focal lengths within squid eyes. We found that squid raised under orange light had proportionately longer eyes and more myopic refractions than those raised under blue light, and when switched between wavelengths, eye size and refractive status changed appropriately within a few days. This demonstrates that squid eye growth is visually guided, and suggests that the complex retina seen in vertebrates may not be required for emmetropisation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Analysis of closed eyes motion using a wireless eye-mask.

    Science.gov (United States)

    Hsieh, Chi-Wen; Kan, Chi-Wen; Jong, Tai-Lang

    2007-04-01

    The closed eyes motion strongly depends on the sleep depth of humans. Typically, the electroencephalogram and motion of ciliary muscle's measurement are common methods of evaluating the sleep status and eyeball motion respectively. The proposed survey is to make a wireless eye-mask for monitoring the closed eye motion non-invasively. The mask with CCD unit, wireless module, and an antenna can send the image of closed eye motion into the image-processing module in PC host. The spatial and frequency features from the eye-mask are analyzed to quantitatively describe relative position, velocity, and moving direction of eyelids and eyeballs. Besides, the motion history can feed into the support vector machine neural network and statistics units to evaluate the appropriate time to trigger the alarm if emergency occurs. The survey not only constructs a system with wireless monitoring the closed eye motion non-invasively but develops an algorithm judging whether the closed eye moving or not.

  3. Novel method for evaluation of eye movements in patients with narcolepsy

    DEFF Research Database (Denmark)

    Christensen, Julie A E; Kempfner, Lykke; Leonthin, Helle L

    2017-01-01

    BACKGROUND: Narcolepsy causes abnormalities in the control of wake-sleep, non-rapid-eye-movement (non-REM) sleep and REM sleep, which inlcudes specific eye movements (EMs). In this study, we aim to evaluate EM characteristics in narcolepsy as compared to controls using an automated detector....... METHODS: We developed a data-driven method to detect EMs during sleep based on two EOG signals recorded as part of a polysomnography (PSG). The method was optimized using the manually scored hypnograms from 36 control subjects. The detector was applied on a clinical sample with subjects suspected...

  4. 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.

  5. 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

  6. Eye movements in vestibular disorders.

    Science.gov (United States)

    Kheradmand, A; Colpak, A I; Zee, D S

    2016-01-01

    The differential diagnosis of patients with vestibular symptoms usually begins with the question: is the lesion central or is it peripheral? The answer commonly emerges from a careful examination of eye movements, especially when the lesion is located in otherwise clinically silent areas of the brain such as the vestibular portions of the cerebellum (flocculus, paraflocculus which is called the tonsils in humans, nodulus, and uvula) and the vestibular nuclei as well as immediately adjacent areas (the perihypoglossal nuclei and the paramedian nuclei and tracts). The neural circuitry that controls vestibular eye movements is intertwined with a larger network within the brainstem and cerebellum that also controls other types of conjugate eye movements. These include saccades and pursuit as well as the mechanisms that enable steady fixation, both straight ahead and in eccentric gaze positions. Navigating through this complex network requires a thorough knowledge about all classes of eye movements to help localize lesions causing a vestibular disorder. Here we review the different classes of eye movements and how to examine them, and then describe common ocular motor findings associated with central vestibular lesions from both a topographic and functional perspective. © 2016 Elsevier B.V. All rights reserved.

  7. Design, Sensing and Control of a Robotic Prosthetic Eye for Natural Eye Movement

    Directory of Open Access Journals (Sweden)

    J. J. Gu

    2006-01-01

    Full Text Available Loss of an eye is a tragedy for a person, who may suffer psychologically and physically. This paper is concerned with the design, sensing and control of a robotic prosthetic eye that moves horizontally in synchronization with the movement of the natural eye. Two generations of robotic prosthetic eye models have been developed. The first generation model uses an external infrared sensor array mounted on the frame of a pair of eyeglasses to detect the natural eye movement and to feed the control system to drive the artificial eye to move with the natural eye. The second generation model removes the impractical usage of the eye glass frame and uses the human brain EOG (electro-ocular-graph signal picked up by electrodes placed on the sides of a person's temple to carry out the same eye movement detection and control tasks as mentioned above. Theoretical issues on sensor failure detection and recovery, and signal processing techniques used in sensor data fusion, are studied using statistical methods and artificial neural network based techniques. In addition, practical control system design and implementation using micro-controllers are studied and implemented to carry out the natural eye movement detection and artificial robotic eye control tasks. Simulation and experimental studies are performed, and the results are included to demonstrate the effectiveness of the research project reported in this paper.

  8. Combining Sodium Hyaluronate and Polyvinylpyrrolidone Therapies for the Rabbit Cornea: A New Approach to Relief of the Human Dry Eye Syndrome.

    Science.gov (United States)

    Ehrenberg, Moshe; Zolotariov, Eyal; Loeb, Emmanuel; Poliansky, Vadim; Levy, Aharon

    2015-09-01

    The novel combination of 0.1% sodium hyaluronate (HA) and 5.0% polyvinylpyrrolidone (PVP) into one eyedrop was investigated to test the hypothesis of its increased relief of dry eye syndrome (DES). We evaluated HA and PVP, either alone, or in combination, by utilizing 16 rabbits, where their right eyes received one or two different eyedrops, and their left eyes, as controls, received none. The DES replica in rabbits was induced by 0.1% benzalkonium chloride (BAC) eyedrops. BAC was instilled into the right eyes of all rabbits, which were divided into four groups of four. In Group 1 M, the rabbits received only BAC. A second eyedrop given to the right eyes of Group 2 M was HA, of Group 3 M was PVP, and of Group 4 M was the combination of both HA and PVP. All eyes were followed clinically for 14 d, and thereafter, examined histopathologically. Clinically, the HA+PVP combination yielded the least perilimbal conjunctival erythema (p < 0.05), and the least corneal epithelial fluorescein staining (p < 0.001) compared to each treatment alone. Histopathologically, all four rabbits' right eyes in the combination group 4 M displayed the greatest preservation of the corneal epithelium (p < 0.001) and of the perilimbal conjunctival goblet cell density (p < 0.001). This unique combination of both HA and PVP into one eyedrop, was more potent than either treatment alone in protecting the ocular surface. A preparation, containing both HA and PVP may become useful for DES patients.

  9. Eyes Wide Open

    Directory of Open Access Journals (Sweden)

    Zoi Manesi

    2016-04-01

    Full Text Available Research from evolutionary psychology suggests that the mere presence of eye images can promote prosocial behavior. However, the “eye images effect” is a source of considerable debate, and findings across studies have yielded somewhat inconsistent support. We suggest that one critical factor may be whether the eyes really need to be watching to effectively enhance prosocial behavior. In three experiments, we investigated the impact of eye images on prosocial behavior, assessed in a laboratory setting. Participants were randomly assigned to view an image of watching eyes (eyes with direct gaze, an image of nonwatching eyes (i.e., eyes closed for Study 1 and averted eyes for Studies 2 and 3, or an image of flowers (control condition. Upon exposure to the stimuli, participants decided whether or not to help another participant by completing a dull cognitive task. Three independent studies produced somewhat mixed results. However, combined analysis of all three studies, with a total of 612 participants, showed that the watching component of the eyes is important for decision-making in this context. Images of watching eyes led to significantly greater inclination to offer help as compared to images of nonwatching eyes (i.e., eyes closed and averted eyes or images of flowers. These findings suggest that eyes gazing at an individual, rather than any proxy to social presence (e.g., just the eyes, serve as a reminder of reputation. Taken together, we conclude that it is “eyes that pay attention” that can lift the veil of anonymity and potentially facilitate prosocial behavior.

  10. Analysis of the cat eye syndrome critical region in humans and the region of conserved synteny in mice: a search for candidate genes at or near the human chromosome 22 pericentromere.

    Science.gov (United States)

    Footz, T K; Brinkman-Mills, P; Banting, G S; Maier, S A; Riazi, M A; Bridgland, L; Hu, S; Birren, B; Minoshima, S; Shimizu, N; Pan, H; Nguyen, T; Fang, F; Fu, Y; Ray, L; Wu, H; Shaull, S; Phan, S; Yao, Z; Chen, F; Huan, A; Hu, P; Wang, Q; Loh, P; Qi, S; Roe, B A; McDermid, H E

    2001-06-01

    We have sequenced a 1.1-Mb region of human chromosome 22q containing the dosage-sensitive gene(s) responsible for cat eye syndrome (CES) as well as the 450-kb homologous region on mouse chromosome 6. Fourteen putative genes were identified within or adjacent to the human CES critical region (CESCR), including three known genes (IL-17R, ATP6E, and BID) and nine novel genes, based on EST identity. Two putative genes (CECR3 and CECR9) were identified, in the absence of EST hits, by comparing segments of human and mouse genomic sequence around two solitary amplified exons, thus showing the utility of comparative genomic sequence analysis in identifying transcripts. Of the 14 genes, 10 were confirmed to be present in the mouse genomic sequence in the same order and orientation as in human. Absent from the mouse region of conserved synteny are CECR1, a promising CES candidate gene from the center of the contig, neighboring CECR4, and CECR7 and CECR8, which are located in the gene-poor proximal 400 kb of the contig. This latter proximal region, located approximately 1 Mb from the centromere, shows abundant duplicated gene fragments typical of pericentromeric DNA. The margin of this region also delineates the boundary of conserved synteny between the CESCR and mouse chromosome 6. Because the proximal CESCR appears abundant in duplicated segments and, therefore, is likely to be gene poor, we consider the putative genes identified in the distal CESCR to represent the majority of candidate genes for involvement in CES.

  11. Learning increases human electroencephalographic coherence during subsequent slow sleep oscillations.

    Science.gov (United States)

    Mölle, Matthias; Marshall, Lisa; Gais, Steffen; Born, Jan

    2004-09-21

    Learning is assumed to induce specific changes in neuronal activity during sleep that serve the consolidation of newly acquired memories. To specify such changes, we measured electroencephalographic (EEG) coherence during performance on a declarative learning task (word pair associations) and subsequent sleep. Compared with a nonlearning control condition, learning performance was accompanied with a strong increase in coherence in several EEG frequency bands. During subsequent non-rapid eye movement sleep, coherence only marginally increased in a global analysis of EEG recordings. However, a striking and robust increase in learning-dependent coherence was found when analyses were performed time-locked to the occurrence of slow oscillations (learning in the slow-oscillatory, delta, slow-spindle, and gamma bands. The findings identify the depolarizing phase of the slow oscillations in humans as a time period particularly relevant for a reprocessing of memories in sleep.

  12. About the Eye

    Medline Plus

    Full Text Available ... First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks ... NEI Office of Science Communications, Public Liaison, and Education. Technical questions about this website can be addressed ...

  13. 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 ...

  14. What Is Dry Eye?

    Medline Plus

    Full Text Available ... 12, 2017 Can lupus affect my vision? May 27, 2017 Is stopping Restasis dangerous? Mar 06, 2017 ... link between seasonal allergens and dry eye Apr 27, 2015 Choosing Wisely When It Comes to Eye ...

  15. Eye muscle repair

    Science.gov (United States)

    ... child may go home. You should have a follow-up visit with the eye surgeon 1 to 2 weeks after the surgery. To prevent infection, you will probably need to put drops or ointment in your child's eyes.

  16. National Eye Institute

    Science.gov (United States)

    ... testing new therapies. Learn more Learn about the Eye and Vision Our web pages for kids make ... illusions, and more. View the site Video: New Eye Imaging Tools The NEI Audacious Goals Initiative is ...

  17. About the Eye

    Medline Plus

    Full Text Available ... Education Programs National Eye Health Education Program (NEHEP) Diabetic Eye Disease Education Program Glaucoma Education Program Low ... iris adjusts the size of the pupil and controls the amount of light that can enter the ...

  18. What Is Dry Eye?

    Medline Plus

    Full Text Available ... vision? May 27, 2017 Is stopping Restasis dangerous? Mar 06, 2017 Why are my eyes bloodshot when ... When It Comes to Eye Care, Part 5 Mar 19, 2013 Follow The Academy Professionals: Education Guidelines ...

  19. 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 ...

  20. Lasik eye surgery - discharge

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000525.htm Lasik eye surgery - discharge To use the sharing features on this page, please enable JavaScript. Lasik eye surgery permanently changes the shape of the cornea ( ...

  1. About the Eye

    Medline Plus

    Full Text Available ... Links to More Information Optical Illusions Printables About the Eye Your eyes are made up of many ... make sense of the world around you. Did You Know? Vision depends on your brain as much ...

  2. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Eye Health Home Annual Meeting Clinical Education Practice Management Member Services Advocacy Foundation About Subspecialties & More Academy Publications EyeNet Ophthalmology Ophthalmology Retina Information for: International Ophthalmologists Media Medical Students Patients and ...

  3. Eye Cosmetic Safety

    Science.gov (United States)

    ... eye (scratching your cornea, for example) with a mascara wand or other applicator. Even a slight scratch ... containers of eye cosmetics. Manufacturers usually recommend discarding mascara two to four months after purchase. Discard dried- ...

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Services Advocacy Foundation About Subspecialties & More Eye Health Home Annual Meeting Clinical Education Practice Management Member Services ... 2015 Choosing Wisely When It Comes to Eye Care, Part 5 Mar 19, 2013 Follow The Academy ...

  5. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Eye Health Home Annual Meeting Clinical Education Practice Management Member Services Advocacy Foundation About Subspecialties & More Academy Publications EyeNet Ophthalmology Ophthalmology Retina Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians ...

  6. About the Eye

    Medline Plus

    Full Text Available ... Clinical Studies Publications Catalog Photos and Images Spanish Language Information Grants and Funding Extramural Research Division of ... National Eye Health Education Program (NEHEP) Diabetic Eye Disease Education Program Glaucoma Education Program Low Vision Education ...

  7. Cultivating the Third Eye

    National Research Council Canada - National Science Library

    Holden, Constance

    2005-01-01

    Zoologist Om Prakash Jangir and his colleagues found that if the removed tadpoles' eyes and raised the animals in a medium enriched with vitamin A, a new eye developed within ten days over the site of the pineal gland...

  8. Eye Injuries at Home

    Science.gov (United States)

    ... Steps to Safer Champagne Celebrations Eye Injuries at Home Leer en Español: Lesiones de los Ojos en ... chore is being done. Preventing Eye Injuries at Home Wearing protective eyewear will prevent 90 percent of ...

  9. About the Eye

    Medline Plus

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

  10. Bags Under Eyes

    Science.gov (United States)

    ... can include: Mild swelling Saggy or loose skin Dark circles When to see a doctor You may not ... Rochester, Minn., July 22, 2014. Related Chemical peel Dark circles under eyes Bags under eyes Symptoms & causes Diagnosis & ...

  11. In vitro assessment of eye irritancy using the Reconstructed Human Corneal Epithelial SkinEthic HCE model: application to 435 substances from consumer products industry.

    Science.gov (United States)

    Cotovio, José; Grandidier, Marie-Hélène; Lelièvre, Damien; Bremond, Christelle; Amsellem, Carolle; Maloug, Saber; Ovigne, Jean-Marc; Loisel-Joubert, Sophie; Lee, Aline Van Der; Minondo, Anne-Marie; Capallere, Christophe; Bertino, Béatrice; Alépée, Nathalie; Tinois-Tessonneaud, Estelle; de Fraissinette, Anne De Brugerolle; Meunier, Jean-Roch; Leclaire, Jacques

    2010-03-01

    The 7th amendment of the EU Cosmetics Directive led to the ban of eye irritation testing for cosmetic ingredients in animals, effective from March 11th 2009. Over the last 20years, many efforts have been made to find reliable and relevant alternative methods. The SkinEthic HCE model was used to evaluate the in vitro eye irritancy potential of substances from a cosmetic industry portfolio. An optimized protocol based on a specific 1-h treatment and a 16-h post-treatment incubation period was first assessed on a set of 102 substances. The prediction model (PM) based on a 50% viability cut-off, allowed to draw up two classes (Irritants and Non-Irritants), with good associated sensitivity (86.2%) and specificity (83.5%). To check the robustness of the method, the evaluated set was expanded up to 435 substances. Final performances maintained a high level and were characterized by an overall accuracy value > 82% when using EU or GHS classification rules. Results showed that the SkinEthic HCE test method is a promising in vitro tool for the prediction of eye irritancy. Optimization datasets were shared with the COLIPA Eye Irritation Project Team and ECVAM experts, and reviewed as part of an ongoing progression to enter an ECVAM prospective validation study for eye irritation. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  12. Eyes Wide Open

    OpenAIRE

    Zoi Manesi; Van Lange, Paul A. M.; Pollet, Thomas V.

    2016-01-01

    Research from evolutionary psychology suggests that the mere presence of eye images can promote prosocial behavior. However, the “eye images effect” is a source of considerable debate, and findings across studies have yielded somewhat inconsistent support. We suggest that one critical factor may be whether the eyes really need to be watching to effectively enhance prosocial behavior. In three experiments, we investigated the impact of eye images on prosocial behavior, assessed in a laboratory...

  13. Extraction of Eye Tracking Movements Using Path Stitching Algorithm

    Science.gov (United States)

    Morita, Souhei; Furukawa, Koichi; Ozaki, Tomonobu

    Researchers are able to estimate what subjects attend to by using eye tracking systems. Existing approaches for analyzing eye movements are very useful to estimate attention to still objects. But they are inadequate to estimate attention to moving objects, although paying attention to moving objects is usual human behavior. Thus, we propose a novel approach and algorithm to estimate attention to moving objects more precisely. Our approach is to extract "eye tracking movements". We phrase both saccadic eye movements and smooth pursuit eye movements as "eye tracking movements". Because previous works reveal that humans often track a moving object by the eye movements when they pay attention to the object, our approach seems to be appropriate. Our algorithm used for extracting eye tracking movements is called Path Stitching (PS) algorithm. The PS algorithm is a kind of Longest Common Subsequence (LCS) discovery algorithms using Dynamic Time Warping (DTW) as a similarity measurement procedure. Eye tracking movements can be regarded as a situation that a subsequence of eye movements' trajectory is similar to a subsequence of the target's trajectory with a small or no time-difference. Because humans track a moving object by the eye movements with locally fluctuated time difference, we think the use of DTW is very appropriate. In addition, to make outputs more comprehensible, we employ the LCS discovery approach for the PS algorithm. The experimental results show that the PS algorithm is more able to extract eye tracking movements than the fixation extracting approach. The fixation extracting approach is the most popular and the strongest approach to analyze eye movements. Therefore, we conclude that our novel approach will advance the analysis of human behavior by the eye movements and human-computer interaction systems they utilize user's eye movements.

  14. Fish eye optics

    Science.gov (United States)

    Hudec, R.; Michalova, S.

    2017-07-01

    We report on small student (high—school) project of the Czech Academy of Sciences dealing with animal (fish) eyes and possible application in science and technology. Albeit most fishes have refractive eyes, the recent discoveries confirm that some fishes have reflective eyes with strange arrangements as well.

  15. 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 ...

  16. Common eye emergencies

    African Journals Online (AJOL)

    2007-10-11

    Oct 11, 2007 ... Common eye emergencies may present as an acute red eye, sudden visual loss or acute ocular trauma. Most eye emergencies will require referral to an ophthalmologist after initial basic examination and primary management. A relevant history of onset and symptoms of the current problem must be ...

  17. What Is Dry Eye?

    Medline Plus

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  18. 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

  19. Eye Care: MedlinePlus Health Topic

    Science.gov (United States)

    ... Institute) Sports and Your Eyes (National Eye Institute) Topic Image MedlinePlus Email Updates Get Eye Care updates by email What's this? GO Related Health Topics Eye Diseases Eye Infections Eye Injuries Eye Wear ...

  20. Sustained eye closure slows saccades

    Science.gov (United States)

    Shaikh, Aasef G.; Wong, Aaron L.; Optican, Lance M.; Miura, Kenichiro; Solomon, David; Zee, David S.

    2010-01-01

    Saccadic eye movements rapidly orient the line of sight towards the object of interest. Pre-motor burst neurons (BNs) controlling saccades receive excitation from superior colliculus and cerebellum, but inhibition by omnipause neurons (OPNs) prevents saccades. When the OPNs pause, BNs begin to fire. It has been presumed that part of the BN burst comes from post-inhibitory rebound (PIR). We hypothesized that in the absence of prior inhibition from OPNs there would be no PIR, and thus the increase in initial firing rate of BNs would be reduced. Consequently, saccade acceleration would be reduced. We measured eye movements and showed that sustained eye closure, which inhibits the activity of OPNs and thus hypothetically should weaken PIR, reduced the peak velocity, acceleration, and deceleration of saccades in healthy human subjects. Saccades under closed eyelids also had irregular trajectories; the frequency of the oscillations underlying this irregularity was similar to that of high-frequency ocular flutter (back-to-back saccades) often seen in normal subjects during attempted fixation at straight ahead while eyes are closed. Saccades and quick phases of nystagmus are generated by the same pre-motor neurons, and we found that the quick-phase velocity of nystagmus was also reduced by lid closure. These changes were not due to a mechanical hindrance to the eyes, because lid closure did not affect the peak velocities or accelerations of the eyes in the “slow-phase” response to rapid head movements of comparable speeds to those of saccades. These results indicate a role for OPNs in generating the abrupt onset and high velocities of saccades. We hypothesize that the mechanism involved is PIR in pre-motor burst neurons. PMID:20573593

  1. School eye health appraisal

    Directory of Open Access Journals (Sweden)

    Desai Sanjiv

    1989-01-01

    Full Text Available School children form an important large target group which must be screened adequately for early detection of eye diseases and prevention of blindness. A total approach in a school eye health programme must include teacher orientation and health education of children in addition to screening for eye diseases. The ocular morbidity pattern in 5135 school children of Jodhpur is discussed in this paper and it is hoped that it will be an indicator to all eye care agencies to help plan their priorities in the delivery of school based eye care.

  2. EYE GAZE TRACKING

    DEFF Research Database (Denmark)

    2011-01-01

    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...

  3. Test-retest repeatability of the pupil light response to blue and red light stimuli in normal human eyes using a novel pupillometer

    DEFF Research Database (Denmark)

    Herbst, Kristina; Sander, Birgit; Milea, Dan

    2011-01-01

    In this study, we evaluated the repeatability of pupil responses to colored light stimuli in healthy subjects using a prototype chromatic pupillometer. One eye of 10 healthy subjects was tested twice in the same day using monochromatic light exposure at two selected wavelengths (660 and 470¿nm, i...

  4. Test-retest repeatability of the pupil light response to blue and red light stimuli in normal human eyes using a novel pupillometer

    DEFF Research Database (Denmark)

    Herbst, Kristina; Sander, Birgit; Milea, Dan

    2011-01-01

    In this study, we evaluated the repeatability of pupil responses to colored light stimuli in healthy subjects using a prototype chromatic pupillometer. One eye of 10 healthy subjects was tested twice in the same day using monochromatic light exposure at two selected wavelengths (660 and 470 nm, i...

  5. Penetration of 0.3% ciprofloxacin, 0.3% ofloxacin, and 0.5% moxifloxacin into the cornea and aqueous humor of enucleated human eyes.

    Science.gov (United States)

    Silva, G C M; Jabor, V A P; Bonato, P S; Martinez, E Z; Faria-E-Sousa, S J

    2017-07-03

    We aimed to quantify the penetration of ciprofloxacin, ofloxacin, and moxifloxacin into the cornea and aqueous humor of cadaver eyes. A total of 60 enucleated eyes, not eligible for corneal transplantation, were divided into three groups and immersed in commercial solutions of 0.3% ciprofloxacin, 0.3% ofloxacin, or 0.5% moxifloxacin for 10 min. Whole corneas and samples of aqueous humor were then harvested and frozen, and drug concentrations analyzed by liquid chromatography tandem mass spectrometry. The mean corneal concentration of moxifloxacin was twice as high as ofloxacin, and the latter was twice as high as ciprofloxacin. The mean concentration of moxifloxacin in the aqueous humor was four times higher than the other antibiotics, and the mean concentrations of ciprofloxacin and ofloxacin were statistically similar. The amount of drug that penetrated the anterior chamber after a 10-min immersion was far below the safe limit of endothelial toxicity of each preparation. Moxifloxacin demonstrated far superior penetration into the cornea and anterior chamber of cadaver eyes compared to ciprofloxacin and ofloxacin. One should not expect endothelial toxicity with the commercial eye drops of ciprofloxacin, ofloxacin, and moxifloxacin that reach the anterior chamber through the cornea.

  6. Fetal eye movements on magnetic resonance imaging.

    Science.gov (United States)

    Woitek, Ramona; Kasprian, Gregor; Lindner, Christian; Stuhr, Fritz; Weber, Michael; Schöpf, Veronika; Brugger, Peter C; Asenbaum, Ulrika; Furtner, Julia; Bettelheim, Dieter; Seidl, Rainer; Prayer, Daniela

    2013-01-01

    Eye movements are the physical expression of upper fetal brainstem function. Our aim was to identify and differentiate specific types of fetal eye movement patterns using dynamic MRI sequences. Their occurrence as well as the presence of conjugated eyeball motion and consistently parallel eyeball position was systematically analyzed. Dynamic SSFP sequences were acquired in 72 singleton fetuses (17-40 GW, three age groups [17-23 GW, 24-32 GW, 33-40 GW]). Fetal eye movements were evaluated according to a modified classification originally published by Birnholz (1981): Type 0: no eye movements; Type I: single transient deviations; Type Ia: fast deviation, slower reposition; Type Ib: fast deviation, fast reposition; Type II: single prolonged eye movements; Type III: complex sequences; and Type IV: nystagmoid. In 95.8% of fetuses, the evaluation of eye movements was possible using MRI, with a mean acquisition time of 70 seconds. Due to head motion, 4.2% of the fetuses and 20.1% of all dynamic SSFP sequences were excluded. Eye movements were observed in 45 fetuses (65.2%). Significant differences between the age groups were found for Type I (p = 0.03), Type Ia (p = 0.031), and Type IV eye movements (p = 0.033). Consistently parallel bulbs were found in 27.3-45%. In human fetuses, different eye movement patterns can be identified and described by MRI in utero. In addition to the originally classified eye movement patterns, a novel subtype has been observed, which apparently characterizes an important step in fetal brainstem development. We evaluated, for the first time, eyeball position in fetuses. Ultimately, the assessment of fetal eye movements by MRI yields the potential to identify early signs of brainstem dysfunction, as encountered in brain malformations such as Chiari II or molar tooth malformations.

  7. Nutrients for the aging eye

    OpenAIRE

    Rasmussen HM; Johnson EJ

    2013-01-01

    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-infla...

  8. The Interaction Between Vision and Eye Movements.

    Science.gov (United States)

    Gegenfurtner, Karl R

    2016-07-05

    The existence of a central fovea, the small retinal region with high analytical performance, is arguably the most prominent design feature of the primate visual system. This centralization comes along with the corresponding capability to move the eyes to reposition the fovea continuously. Past research on visual perception was mainly concerned with foveal vision while the observers kept their eyes stationary. Research on the role of eye movements in visual perception emphasized their negative aspects, for example, the active suppression of vision before and during the execution of saccades. But is the only benefit of our precise eye movement system to provide high acuity of the small foveal region, at the cost of retinal blur during their execution? In this review, I will compare human visual perception with and without saccadic and smooth pursuit eye movements to emphasize different aspects and functions of eye movements. I will show that the interaction between eye movements and visual perception is optimized for the active sampling of information across the visual field and for the calibration of different parts of the visual field. The movements of our eyes and visual information uptake are intricately intertwined. The two processes interact to enable an optimal perception of the world, one that we cannot fully grasp by doing experiments where observers are fixating a small spot on a display. © The Author(s) 2016.

  9. 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.

  10. '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

  11. Calculation of SAR and temperature rise in a high-resolution vascularized model of the human eye and orbit when exposed to a dipole antenna at 900, 1500 and 1800 MHz.

    Science.gov (United States)

    Flyckt, V M M; Raaymakers, B W; Kroeze, H; Lagendijk, J J W

    2007-05-21

    The eye is considered to be a critical organ when determining safety standards for radiofrequency radiation. With a detailed anatomy of the human eye and orbit inserted in a whole-head model, the specific absorption rates (SARs) and thermal effects were determined under exposure to a dipole antenna representing a mobile phone operating at 900, 1500 and 1800 MHz with an output power of 1 W. The temperature rise was calculated by taking the blood flow into account either by the Pennes bioheat model or by including the discrete vasculature (DIVA). In addition, a simple spherical model using constant heat transfer coefficients was used. Peak SARs in the humour are 4.5, 7.7 and 8.4 W kg(-1) for 900, 1500 and 1800 MHz respectively. Averaged over the whole eyeball, the SARs are 1.7, 2.5 and 2.2 W kg(-1). The maximum temperature rises in the eye due to the exposure are 0.22, 0.27 and 0.25 degrees C for exposure of 900, 1500 and 1800 MHz, respectively, calculated with DIVA. For the Pennes bioheat model, the temperature rises are slightly lower: 0.19, 0.24, 0.22 degrees C respectively. For the simple spherical model, the maximum temperature rises are 0.15, 0.22 and 0.20 degrees C. The peak temperature is located in the anterior part of the lens for 900 MHz and deeper in the eye for higher frequencies, and in the posterior part of the lens for 1500 MHz and close to the centre of the eyeball for 1800 MHz. For these RF safety applications, both DIVA and the Pennes bioheat model could be used to relate the SAR distributions to the resulting temperature distributions. Even though, for these artificial exposure conditions, the SAR values are not in compliance with safety guidelines, the maximum temperature rises in the eye are too small to give harmful effects. The temperature in the eye also remains below body core temperature.

  12. 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.

  13. 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 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.

  14. What Is Dry Eye?

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    Full Text Available ... Services Advocacy Foundation About Subspecialties & More Eye Health Home Annual Meeting Clinical Education Practice Management Member Services Advocacy Foundation About Subspecialties & ...

  15. 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 Services Advocacy Foundation About Subspecialties & ...

  16. Ocular Emergencies: Red Eye.

    Science.gov (United States)

    Tarff, Andreina; Behrens, Ashley

    2017-05-01

    "Red eye" is used as a general term to describe irritated or bloodshot eyes. It is a recognizable sign of an acute/chronic, localized/systemic underlying inflammatory condition. Conjunctival injection is most commonly caused by dryness, allergy, visual fatigue, contact lens overwear, and local infections. In some instances, red eye can represent a true ocular emergency that should be treated by an ophthalmologist. A comprehensive assessment of red eye conditions is required to preserve the patients visual function. Severe ocular pain, significant photophobia, decreased vision, and history of ocular trauma are warning signs demanding immediate ophthalmological consultation. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. 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 ...

  18. What Is Dry Eye?

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

  19. Learning optimal eye movements to unusual faces.

    Science.gov (United States)

    Peterson, Matthew F; Eckstein, Miguel P

    2014-06-01

    Eye movements, which guide the fovea's high resolution and computational power to relevant areas of the visual scene, are integral to efficient, successful completion of many visual tasks. How humans modify their eye movements through experience with their perceptual environments, and its functional role in learning new tasks, has not been fully investigated. Here, we used a face identification task where only the mouth discriminated exemplars to assess if, how, and when eye movement modulation may mediate learning. By interleaving trials of unconstrained eye movements with trials of forced fixation, we attempted to separate the contributions of eye movements and covert mechanisms to performance improvements. Without instruction, a majority of observers substantially increased accuracy and learned to direct their initial eye movements towards the optimal fixation point. The proximity of an observer's default face identification eye movement behavior to the new optimal fixation point and the observer's peripheral processing ability were predictive of performance gains and eye movement learning. After practice in a subsequent condition in which observers were directed to fixate different locations along the face, including the relevant mouth region, all observers learned to make eye movements to the optimal fixation point. In this fully learned state, augmented fixation strategy accounted for 43% of total efficiency improvements while covert mechanisms accounted for the remaining 57%. The findings suggest a critical role for eye movement planning to perceptual learning, and elucidate factors that can predict when and how well an observer can learn a new task with unusual exemplars. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Brain-machine interface for eye movements.

    Science.gov (United States)

    Graf, Arnulf B A; Andersen, Richard A

    2014-12-09

    A number of studies in tetraplegic humans and healthy nonhuman primates (NHPs) have shown that neuronal activity from reach-related cortical areas can be used to predict reach intentions using brain-machine interfaces (BMIs) and therefore assist tetraplegic patients by controlling external devices (e.g., robotic limbs and computer cursors). However, to our knowledge, there have been no studies that have applied BMIs to eye movement areas to decode intended eye movements. In this study, we recorded the activity from populations of neurons from the lateral intraparietal area (LIP), a cortical node in the NHP saccade system. Eye movement plans were predicted in real time using Bayesian inference from small ensembles of LIP neurons without the animal making an eye movement. Learning, defined as an increase in the prediction accuracy, occurred at the level of neuronal ensembles, particularly for difficult predictions. Population learning had two components: an update of the parameters of the BMI based on its history and a change in the responses of individual neurons. These results provide strong evidence that the responses of neuronal ensembles can be shaped with respect to a cost function, here the prediction accuracy of the BMI. Furthermore, eye movement plans could be decoded without the animals emitting any actual eye movements and could be used to control the position of a cursor on a computer screen. These findings show that BMIs for eye movements are promising aids for assisting paralyzed patients.

  1. 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

  2. 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…

  3. What Is Dry Eye?

    Medline Plus

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

  4. What Is Dry Eye?

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

  5. About the Eye

    Medline Plus

    Full Text Available ... Vision Research & Ophthalmology (DIVRO) Student Training Programs To search for current job openings visit HHS USAJobs Home > NEI for Kids > About the Eye All About Vision About the Eye Ask a Scientist Video Series Glossary The Visual System Your Eyes’ ...

  6. Smoking and Eye Health

    Science.gov (United States)

    ... Patient Stories Español Eye Health / Tips & Prevention Sections Smoking and Eye Disease Leer en Español: El Cigarrillo ... By: Brenda Pagan-Duran MD Apr. 27, 2017 Smoking contributes to a number of major health problems, ...

  7. Chemotherapy in eye cancer

    African Journals Online (AJOL)

    Chemotherapy in eye cancer. Chemotherapy is one of several treatment strategies used to halt the uncontrolled division, proliferation and unpredictable growth patterns of malignant cells. R Dolland, BSc, MB BCh, FC Ophth (SA). Consultant, St John Eye Hospital, Division of Ophthalmology, Department of Neurosciences, ...

  8. What Is Dry Eye?

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    Full Text Available ... Media Medical Students Patients and Public Technicians and Nurses Senior Ophthalmologists Young Ophthalmologists Tools and Services EyeCare ... Media Medical Students Patients and Public Technicians and Nurses Senior Ophthalmologists Young Ophthalmologists Tools and Services EyeCare ...

  9. What Is Dry Eye?

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    Full Text Available ... and Nurses Senior Ophthalmologists Young Ophthalmologists Tools and Services Emergency Relief EyeCare America Help IRIS Registry Medicare ... and Nurses Senior Ophthalmologists Young Ophthalmologists Tools and Services Emergency Relief EyeCare America Help IRIS Registry Medicare ...

  10. 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...

  11. LASIK Eye Surgery

    Science.gov (United States)

    ... Persistent dry eyes Unstable vision due to medications, hormonal changes, pregnancy, breast-feeding or age Keratitis, uveitis, herpes simplex ... to certain conditions, such as abnormal wound healing, hormonal imbalances or pregnancy. Sometimes this change in vision is due to another eye problem, ...

  12. 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.

  13. What Is Dry Eye?

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    Full Text Available ... Nurses Senior Ophthalmologists Young Ophthalmologists Tools and Services Emergency Relief EyeCare America Help IRIS Registry Medicare Physician ... Nurses Senior Ophthalmologists Young Ophthalmologists Tools and Services Emergency Relief EyeCare America Help IRIS Registry Medicare Physician ...

  14. What Is Dry Eye?

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    Full Text Available ... IRIS Registry Medicare Physician Payment Meetings and Deadlines Museum of Vision Ophthalmology Job Center Our Sites EyeWiki ... IRIS Registry Medicare Physician Payment Meetings and Deadlines Museum of Vision Ophthalmology Job Center Our Sites EyeWiki ...

  15. What Is Dry Eye?

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    Full Text Available ... Public Technicians and Nurses Senior Ophthalmologists Young Ophthalmologists Tools and Services EyeCare America Help IRIS Registry Medicare ... Public Technicians and Nurses Senior Ophthalmologists Young Ophthalmologists Tools and Services EyeCare America Help IRIS Registry Medicare ...

  16. What Is Dry Eye?

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    Full Text Available ... Payment Meetings and Deadlines Museum of Vision Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive ... Payment Meetings and Deadlines Museum of Vision Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive ...

  17. What Is Dry Eye?

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    Full Text Available ... Vision Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive Surgery Subspecialties Cataract/Anterior Segment Comprehensive ... Vision Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive Surgery Subspecialties Cataract/Anterior Segment Comprehensive ...

  18. About the Eye

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    Full Text Available ... National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and other programs ... search for current job openings visit HHS USAJobs Home > NEI for Kids > About the Eye All About ...

  19. Coupling of Thalamocortical Sleep Oscillations Are Important for Memory Consolidation in Humans.

    Directory of Open Access Journals (Sweden)

    Mohammad Niknazar

    Full Text Available Sleep, specifically non-rapid eye movement (NREM sleep, is thought to play a critical role in the consolidation of recent memories. Two main oscillatory activities observed during NREM, cortical slow oscillations (SO, 0.5-1.0 Hz and thalamic spindles (12-15 Hz, have been shown to independently correlate with memory improvement. Yet, it is not known how these thalamocortical events interact, or the significance of this interaction, during the consolidation process. Here, we found that systemic administration of the GABAergic drug (zolpidem increased both the phase-amplitude coupling between SO and spindles, and verbal memory improvement in humans. These results suggest that thalamic spindles that occur during transitions to the cortical SO Up state are optimal for memory consolidation. Our study predicts that the timely interactions between cortical and thalamic events during consolidation, contribute to memory improvement and is mediated by the level of inhibitory neurotransmission.

  20. Analysis of an international collaboration for capacity building of human resources for eye care: case study of the college-college VISION 2020 LINK.

    Science.gov (United States)

    Mwangi, Nyawira; Zondervan, Marcia; Bascaran, Covadonga

    2017-03-14

    There is an extreme health workforce shortage in Eastern, Central, and Southern Africa. Shortage of eye care workers impedes effective implementation of prevention of blindness programs. The World Health Organization has identified education, partnership, leadership, financing, and policy as intertwined interventions that are critical to resolving this crisis on the long term. The VISION 2020 LINK between the College of Ophthalmology of Eastern, Central, and Southern Africa and the Royal College of Ophthalmologists in the United Kingdom aims to increase the quantity and quality of eye care training in East, Central, and Southern Africa through a focus on five strategic areas: fellowship examination for ophthalmologists, training the trainers, curriculum development for residents in ophthalmology and ophthalmic clinical officers, continuous professional development (CPD), and mentoring program for young ophthalmologists. This study examined how education and partnership can be linked to improve eye care, through an evaluation of this north-south link based on its own targets and established frameworks to guide north-south links. An exploratory qualitative case study design was used. Twenty-nine link representatives were recruited through purposive sampling and snowballing. Face-to-face interviews were conducted using a semi-structured interview schedule that incorporated the components of a successful link from an existing framework. Documents pertaining to the link were also examined. Thematic analysis was used for data analysis. The findings revealed that the perception to the contribution of the link to eye care in the region is generally positive. Process indicators showed that the targets in three strategic objectives of the link have been achieved. Framework-based evaluation also showed that the link is successful. Mutual learning and development of friendships were the most commonly identified success factors. Inadequate awareness of the link by college

  1. Dry Eye Disease and Microbial Keratitis: Is There a Connection?

    Science.gov (United States)

    Narayanan, Srihari; Redfern, Rachel L.; Miller, William L.; Nichols, Kelly K.; McDermott, Alison M.

    2013-01-01

    Dry eye is a common ocular surface disease of multifactorial etiology characterized by elevated tear osmolality and inflammation leading to a disrupted ocular surface. The latter is a risk factor for ocular surface infection, yet overt infection is not commonly seen clinically in the typical dry eye patient. This suggests that important innate mechanisms operate to protect the dry eye from invading pathogens. This article reviews the current literature on epidemiology of ocular surface infection in dry eye patients and laboratory-based studies on innate immune mechanisms operating at the ocular surface and their alterations in human dry eye and animal models. The review highlights current understanding of innate immunity in dry eye and identifies gaps in our knowledge to help direct future studies to further unravel the complexities of dry eye disease and its sequelae. PMID:23583043

  2. Structural neural substrates of reading the mind in the eyes

    Directory of Open Access Journals (Sweden)

    Wataru eSato

    2016-04-01

    Full Text Available The ability to read the minds of others in their eyes plays an important role in human adaptation to social environments. Behavioral studies have resulted in the development of a test to measure this ability (Reading the Mind in the Eyes Test, revised version; Eyes Test, and have demonstrated that this ability is consistent over time. Although functional neuroimaging studies revealed brain activation while performing the Eyes Test, the structural neural substrates supporting consistent performance on the Eyes Test remain unclear. In this study we assessed the Eyes Test and analyzed structural magnetic resonance images using voxel-based morphometry in healthy participants. Test performance was positively associated with the gray matter volumes of the dorsomedial prefrontal cortex, inferior parietal lobule (temporoparietal junction, and precuneus in the left hemisphere. These results suggest that the fronto-temporoparietal network structures support the consistent ability to read the mind in the eyes.

  3. An eye tracking system for monitoring face scanning patterns reveals the enhancing effect of oxytocin on eye contact in common marmosets.

    Science.gov (United States)

    Kotani, Manato; Shimono, Kohei; Yoneyama, Toshihiro; Nakako, Tomokazu; Matsumoto, Kenji; Ogi, Yuji; Konoike, Naho; Nakamura, Katsuki; Ikeda, Kazuhito

    2017-09-01

    Eye tracking systems are used to investigate eyes position and gaze patterns presumed as eye contact in humans. Eye contact is a useful biomarker of social communication and known to be deficient in patients with autism spectrum disorders (ASDs). Interestingly, the same eye tracking systems have been used to directly compare face scanning patterns in some non-human primates to those in human. Thus, eye tracking is expected to be a useful translational technique for investigating not only social attention and visual interest, but also the effects of psychiatric drugs, such as oxytocin, a neuropeptide that regulates social behavior. In this study, we report on a newly established method for eye tracking in common marmosets as unique New World primates that, like humans, use eye contact as a mean of communication. Our investigation was aimed at characterizing these primates face scanning patterns and evaluating the effects of oxytocin on their eye contact behavior. We found that normal common marmosets spend more time viewing the eyes region in common marmoset's picture than the mouth region or a scrambled picture. In oxytocin experiment, the change in eyes/face ratio was significantly greater in the oxytocin group than in the vehicle group. Moreover, oxytocin-induced increase in the change in eyes/face ratio was completely blocked by the oxytocin receptor antagonist L-368,899. These results indicate that eye tracking in common marmosets may be useful for evaluating drug candidates targeting psychiatric conditions, especially ASDs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Ancient and contemporary history of artificial eyes.

    Science.gov (United States)

    Danz, W

    1990-01-01

    Throughout history, the human eye has been mentioned by authors as the most precious of gifts. It unveils the entire outer world to our consciousness, gives life expression and dignity to the face. The loss of an eye must therefore have always been regarded as the greatest misfortune. The ancient cultures of Babylon, Jericho, and Egypt used "art-eyes" in mummies, sarcophagus lids, and statues; they were made from precious stones, silver, gold, and copper as a symbol of light and life in their religious beliefs. Most of the recorded sources concerning the ancient practice of medicine were among the scrolls contained in the library of Alexandria. In the period between the Roman Colonial wars, the rise of Christianity and the fall of Alexandria to Arabs in 642 A.D., almost all of these sources, including those concerning the practice of Ophthalmology were lost. The largest collection of antiquity "art-eyes" and artificial eyes, mentioned in this paper, are found in the collection of the firm of Mueller and Sohne, Wiesbaden, Germany. They include the progress made in human artificial eyes to modern times. Historically, man has tried to alleviate the psychological suffering incurred by the loss of an eye, by hiding or covering the defacement with a patch. Of greater significance are the efforts made by the ophthalmologist and the ocularist (past and present) to restore functionally and cosmetically the natural facial appearance by means of an ocular prosthesis that corresponds to the remaining natural eye. Associated problems frequently concern both the reconstructive surgeon, who must be informed of the ocular prosthetic possibilities that are within the capacity of the ocularist, and the ocularist, who must create the prosthesis.

  5. Advocacy for eye care

    Directory of Open Access Journals (Sweden)

    Thulasiraj D Ravilla

    2012-01-01

    Full Text Available The effectiveness of eye care service delivery is often dependant on how the different stakeholders are aligned. These stakeholders range from the ministries of health who have the capacity to grant government subsidies for eye care, down to the primary healthcare workers who can be enrolled to screen for basic eye diseases. Advocacy is a tool that can help service providers draw the attention of key stakeholders to a particular area of concern. By enlisting the support, endorsement and participation of a wider circle of players, advocacy can help to improve the penetration and effectiveness of the services provided. There are several factors in the external environmental that influence the eye care services - such as the availability of trained manpower, supply of eye care consumables, government rules and regulations. There are several instances where successful advocacy has helped to create an enabling environment for eye care service delivery. Providing eye care services in developing countries requires the support - either for direct patient care or for support services such as producing trained manpower or for research and dissemination. Such support, in the form of financial or other resources, can be garnered through advocacy.

  6. Flow inside an eye under vitreous surgery

    Science.gov (United States)

    Kono, Daiki; Sakamoto, Shun; Sakakibara, Jun

    2014-11-01

    Vitreous is a clear gel filling the space between crystalline lens and retina in human eye. Under circumstances where the vitreous becomes opaque due to bleeding or other disease, ophthalmologist removes the vitreous from eye by cutting and sucking through a pipe named vitreous cutter, and meanwhile replaces fluid in the eye with a balanced salt solution by injecting it through the infusion port. Jet flow from the infusion port may cause intense flow. Consequently, this may generate a pressure and a shear stress on the retinal wall and possibly lead to the damage of retinal cell. In this study, we visualized the flow inside eye and estimated the shear stress on the retinal wall under the vitreous surgery. Instead of using human eye, we used a spherical shell model simulating human eyeball, and measured the two dimensional distribution of two-component velocity by PIV. Under the condition of Re=66 to 99, which meet in the actual operation, the maximum shear stress reaches 0.4 Pa. This value is insufficient to cause retinal detachment, while any physiological effect on the retinal endothelial cells is still unclear. Flow field under higher Re will be presented in the talk. Supported by Grants-in-Aid for Scientific Research of Japan Society for the Promotion of Science under Grant No. 25289026.

  7. Aquaporins in the Eye

    DEFF Research Database (Denmark)

    Tran, Thuy Linh; Hamann, Steffen; Heegaard, Steffen

    2017-01-01

    The major part of the eye consists of water . Continuous movement of water and ions between the ocular compartments and to the systemic circulation is pivotal for many physiological functions in the eye. The movement of water facilitates removal of the many metabolic products of corneal-, ciliary...... pressure. In the retina, water is transported into the vitreous body and across the retinal pigment epithelium to regulate the extracellular environment and the hydration of the retina. Aquaporins (AQPs ) take part in the water transport throughout the eye....

  8. Clinical study on high concentrations of sodium hyaluronate eye drops for moderate to severe dry eye

    OpenAIRE

    Yu-Jing Tian; Qin Zhang

    2014-01-01

    AIM: To observe the efficacy of high concentrations of sodium hyaluronate(3g/L SH)for moderate to severe dry eye. METHODS: Forty moderate to severe dry eye patients were included in the study according to the diagnosis criteria and randomized into two groups. The patients of the trial group received topical administration of high concentration sodium hyaluronate(3g/L), and those of the control group received sodium hyaluronate(1g/L)plus recombinant human epidermal growth factor. The dry eye s...

  9. 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.

  10. What Is Dry Eye?

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  11. Eye Injuries (For Parents)

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    ... of your child's routine activities, such as a sport , follow up by investing in an ounce of prevention — protective goggles or unbreakable glasses ... Your Child's Medical History First Aid: Eye Injuries Your Child's Vision What ...

  12. What Is Dry Eye?

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    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. What Is Dry Eye?

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  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. 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).

  16. What Is Dry Eye?

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    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 lupus affect my vision? May 27, 2017 Is ...

  17. What Is Dry Eye?

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    Full Text Available ... plug? Sep 12, 2017 Can you explain why I have halos and blurry vision in the morning? ... 06, 2017 Why are my eyes bloodshot when I wake up? Jun 26, 2016 Find an Ophthalmologist ...

  18. About the Eye

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    Full Text Available ... support research, training, health information dissemination, and other programs with respect to blinding eye diseases, visual disorders, ... and Funding Extramural Research Division of Extramural Science Programs Division of Extramural Activities Extramural Contacts NEI Division ...

  19. What Is Dry Eye?

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  20. About the Eye

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    Full Text Available ... Extramural Science Programs Division of Extramural Activities Extramural ... is the small, sensitive area of the retina needed for central vision. It contains the fovea. Lens is the clear part of the eye behind ...

  1. About the Eye

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    Full Text Available ... are made up of many different parts that work together to help you see. Check out the ... Learn how the different parts of your eye work together so you can see and make sense ...

  2. About the Eye

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    Full Text Available ... part of your eye and what it does. Macula (MACK-yoo-luh) is the small, sensitive area ... FOH-vee-uh) is the center of the macula, where your vision is sharpest. Optic nerve (OP- ...

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    Full Text Available ... eyes don’t make enough tears or something affects one or more layers of the tear film. ... in the morning? Jun 12, 2017 Can lupus affect my vision? May 27, 2017 Is stopping Restasis ...

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  13. Eye Complications in IBD

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    ... necessary. Another possible consequence may be night blindness. Artificial tears provide relief of symptoms. Vitamin A supplements, ... of the lens of the eye that impairs vision). SUMMARY Although not everyone with Crohn’s disease or ...

  14. About the Eye

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  18. Using Eye Makeup

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    ... in a moving vehicle. Do not separate your mascara-clumped lashes with sharp items. If you tend ... all eye makeup at night before sleeping, especially mascara that can stick to the lashes. Brush a ...

  19. Standard eye exam

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    ... the eye ( glaucoma ) using a method called tonometry Color blindness is tested using cards with colored dots that ... Astigmatism (abnormally curved cornea) Blocked tear duct Cataracts Color blindness Corneal abrasion (or dystrophy) Corneal ulcers and infections ...

  20. Sports and Your Eyes

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    ... at high risk for eye injuries. Baseball Basketball Water Sports Boxing ... Protective Eyewear Fast Facts Everyone should wear protective eyewear. Ordinary prescription glasses, contact lenses, and sunglasses won’t protect you from injuries. ...