874 resultados para Eye, Artifical
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Background There is a potential risk of infection with blood-borne viruses if a doctor receives a blood splash to a mucous membrane. The quantification of facial contamination with blood has never been documented in the context of dermatological surgery. Objectives (i) To identify the number of facial blood splashes that occur during skin surgery and to identify the procedures that present higher risks for the operator and assistant. (ii) To assess the provision of eye protection and attitudes to its use in dermatological surgery in the U.K. Methods (i) Prospective, observational study in the skin surgery suite of a U.K. teaching hospital assessing 100 consecutive dermatological surgery procedures, plus 100 consecutive operations in which an assistant was present. Primary outcome: number of face-mask visors with at least one blood splash. Secondary outcomes: to identify if any of the following variables influenced the occurrence of a blood splash: grade of operator, site and type of procedure, and the use of electrocautery. (ii) A postal survey of all U.K.-based members of the British Society of Dermatological Surgery (BSDS) was conducted assessing facilities available and the attitudes of U.K.-based clinicians to the use of face masks during surgery. Results (i) In 33% of all surgical procedures there was at least one facial splash to the operator (range 1–75) and in 15% of procedures the assistant received at least one splash (range 1–11). Use of monopolar electrocautery was significantly less likely to result in splashes to the mask compared with bipolar electrocautery [odds ratio (OR) 0Æ04; 95% confidence interval (CI) 0Æ01–0Æ19]. Compared with the head/neck, operations on the body were significantly more likely to result in splashes to the mask (OR 6Æ52) (95% CI 1Æ7–25Æ07). The type of procedure and the status of the operator did not have a bearing on the likelihood of receiving a splash to the mask. (ii) From the survey, 33 of 159 (20Æ8%) of BSDS members had no face masks available and 54 of 159 (34Æ0%) did not wear any facial protection while operating. The majority (53Æ5%) thought they received a splash in £ 1% of procedures. Conclusions There is a substantial risk of a splash of blood coming into contact with the face during dermatological surgery for both the operator and assistant, regardless of the procedure. The risk of receiving a blood splash to the face may be substantially underestimated by U.K.-based dermatologists. The use of protective eyewear is advisable at all times, but particularly when using bipolar electrocautery, or when operating on high-risk individuals.
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Objective Primary open angle glaucoma (POAG) is the most common type of glaucoma in Africa. We carried out a study to determine the clinical presentation pattern of patients with primary open angle glaucoma (POAG) at a tertiary hospital in Malawi. Design A cross-sectional study Setting Lions Sight First Eye Hospital—a major referral and teaching state eye hospital in Blantyre, Malawi Subjects Study participants were newly diagnosed POAG patients at specialist eye clinic during study period. Results A total of 60 POAG patients were recruited into the study. The mean age was 58.7 years (SD= 16.6, range 18 - 86). There were more male (44, 73.3%) than female (16, 27.7%) patients. The majority of patients (73%) presented one year after onset of visual symptoms. Twenty-six patients (43%) had unilateral blindness (visual acuity < 3/60; WHO classification), while nine patients (15%) presented with bilateral blindness. A vertical cup-to-disc ratio (CDR) of 0.8 or worse was seen in 92 eyes (79%). The mean intraocular pressure (IOP) reading was 35.5 mmHg (SD 13.30). Of the thirty-three eyes that successfully underwent visual field analysis, very advanced defects were recorded in 12 eyes (36%). Conclusion This study demonstrates delayed presentation and male predominance among POAG patients at a tertiary eye hospital in Malawi. Glaucoma intervention programmes should aim at identifying patients with treatable glaucoma with particular attention to women.
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Purpose. To analyze the levels of the diadenosine polyphosphates Ap4A and Ap5A in tears, in a set of control subjects and in groups of symptomatic and nonsymptomatic persons with dry eye. Methods. Ninety-seven subjects participated in the study. The subjects were divided into five experimental groups: control subjects; symptomatic patients with normal tear secretion; symptomatic patients with low tear secretion; forced blink; and corneal mechanical stimulation provided by a gas esthesiometer. The Schirmer I test was used to measure and collect tear secretions from each subject. All samples were processed by high pressure liquid chromatography (HPLC) and their Ap4A and Ap5A levels determined. Results. The levels of Ap4A and Ap5A in tears were greater in all symptomatic patients than in control subjects, especially in symptomatic subjects with low tear secretion. Within the symptomatic subjects with normal tear secretion, significant differences in concentrations of Ap4A and Ap5A were found between men and women. In the forced blink experiments, concentrations of the Ap4A and Ap5A rose with increasing blink frequency. When the cornea was mechanically stimulated, the levels of Ap4A and Ap5A rose significantly during both moderate and high-flow rate tests. Conclusions. The increased levels of Ap4A and Ap5A in tears of patients with dry eye allow these dinucleotides to be used as objective biomarkers in dry eye conditions.
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Over the last few decades, the importance of ophthalmic examination in neurodegenerative diseases of the CNS has reportedly increased. The retina is an extension of the CNS and thus should not be surprising to find abnormal results in both the test exploring visual processing and those examining the retina of patients with CNS degeneration. Current in vivo imaging techniques are allowing ophthalmologists to detect and quantify data consistent with the histopathological findings described in the retinas of Alzheimer’s disease (AD) patients and may help to reveal unsuspected retinal and optic‐nerve repercussions of other CNS diseases. In this chapter, we perform an analysis of the physiological changes in ocular and cerebral ageing. We analyse the ocular manifestations in CNS disorders such as stroke, AD and Parkinson’s disease. In addition, the pathophysiology of both the eye and the visual pathway in AD are described. The value of the visual psychophysical tests in AD diagnosis is reviewed as well as the main findings of the optical coherence tomography as a contribution to the diagnosis and monitoring of the disease. Finally, we examine the association of two neurodegenerative diseases, AD and glaucoma, as mere coincidence or possible role in the progression of the neurodegeneration.
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Thirteen international netballers viewed static images of scenarios taken from netball open play. Two ‘team mates’, each marked by one opponent, could be seen in each image; each team mate-opponent pair was located on opposite sides of the vertical meridian, such that a binary response was required (‘left’ or ‘right’) from the participant, in order to select a team mate to whom they would pass the ball. For each trial, a spoken word (“left”/“right”) was presented monaurally at the onset of the visual image. Spatially invalid auditory cues (i.e., in the ear contralateral to the correct passing option), reduced performance accuracy relative to valid ones. Semantically invalid cues (e.g., a call of “left” when the target was right-located), increased response times relative to valid ones. However, there were no accompanying changes in visual attention to the team mates and their markers. The effects of auditory cues on covert attentional shifts and decision-making are discussed.
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Analisi sperimentale svolta per valutare come la segnaletica di cantiere, se percepita correttamente, influenza la guida degli utenti che circolano sulla strada interessata da lavorazioni di tipo cantieristico. L'analisi si prefigge anche lo scopo di trovare le soluzioni necessarie per garantire il livello di sicurezza più alto possibile sia per gli utenti che si ritrovano a stretto contatto con il cantiere, che per lavoratori che vi operano.
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PURPOSE: To assess the relationship between short-term and long-term changes in power at different corneal locations relative to the change in central corneal power and the 2-year change in axial elongation relative to baseline in children fitted with orthokeratology contact lenses (OK). METHODS: Thirty-one white European subjects 6 to 12 years of age and with myopia −0.75 to −4.00 DS and astigmatism ≤1.00 DC were fitted with OK. Differences in refractive power 3 and 24 months post-OK in comparison with baseline and relative to the change in central corneal power were determined from corneal topography data in eight different corneal regions (i.e., N[nasal]1, N2, T[temporal]1, T2, I[inferior]1, I2, S[superior]1, S2), and correlated with OK-induced axial length changes at two years relative to baseline. RESULTS: After 2 years of OK lens wear, axial length increased by 0.48±0.18 mm (P0.05). CONCLUSION: The reduction in central corneal power and relative increase in paracentral and pericentral power induced by OK over 2 years were not significantly correlated with concurrent changes in axial length of white European children.
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A distributed network of cortical and subcortical brain regions mediates the control of voluntary behavior, but it is unclear how this complex system may flexibly shift between different behavioral events. This thesis describes the neurophysiological changes in several key nuclei across the brain during flexible behavior, using saccadic eye movements in rhesus macaque monkeys. We examined five nuclei critical for saccade initiation and modulation: the frontal eye field (FEF) in the cerebral cortex, the subthalamic nucleus (STN), caudate nucleus (CD), and substantia nigra pars reticulata (SNr) in the basal ganglia (BG), and the superior colliculus (SC) in the midbrain. The first study tested whether a ‘threshold’ theory of how neuronal activity cues saccade initiation is consistent with the flexible control of behavior. The theory suggests there is a fixed level of FEF and SC neuronal activation at which saccades are initiated. Our results provide strong evidence against a fixed saccade threshold in either structure during flexible behavior, and indicate that threshold variability might depend on the level of inhibitory signals applied to the FEF or SC. The next two studies investigated the BG network as a likely candidate to modulate a saccade initiation mechanism, based on strong inhibitory output signals from the BG to the FEF and SC. We investigated the STN and CD (BG input), and the SNr (BG oculomotor output) to examine changes across the BG network. This revealed robust task-contingent shifts in BG signaling (Chapter 3), which uniquely impacted saccade initiation according to behavioral condition (Chapters 3 and 4). The thesis concludes with a published short review of the mechanistic effects of BG deep brain stimulation (Chapter 5), and a general discussion including proof of concept saccade behavioral changes in an MPTP-induced Parkinsonian model (Chapter 6). The studies presented here demonstrate that the conditions for saccade initiation by the FEF and SC vary according to behavioral condition, while simultaneously, large-scale task dependent shifts occur in BG signaling consistent with the observed modulation of FEF and SC activity. Taken together, these describe a mechanistic framework by which the cortico-BG loop may contribute to the flexible control of behavior.
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The purpose of this thesis is to investigate and understand the effect of a servicescape’s ambient and social conditions on consumers’ service encounter experience and their approach/avoidance behavior in a retail context. In three papers, with a total sample of over 1600 participants (including 550 actual consumers) and seven experiments, the author investigates the effect of music (ambient stimuli), employees’ self-disclosure (verbal social stimuli) and employees’ gazing behavior (nonverbal social stimuli) on consumers’ service encounter experience and approach/avoidance behavior in a retail store. Paper I comprised two experiments, and the aim was to investigate the influence of music on emotions, approach/avoidance behavior. Paper II comprised two experiments, and the aim was to investigate the effect of frontline employees’ personal self-disclosure on consumers’ reciprocal behavior. Paper III comprised three experiments, and the aim was to investigate the influence of employee’s direct eye gaze/ averted eye gaze on consumer emotions, social impression of the frontline employee and encounter satisfaction in different purchase situations. The results in this thesis show that music affects consumers in both positive and negative ways (Paper I). Self-disclosure affects consumers negatively, in such a way that it decreases encounter satisfaction (Paper II) and, finally, eye gaze affects consumers by regulating both positively – and in some cases also negatively – consumers’ social impression of the frontline employee and their encounter satisfaction (Paper III). The conclusions of this thesis are that both ambient and social stimuli in a servicescape affect consumers’ internal responses, which in turn affect their behavior. Depending on the purchase situation, type of retail, and stimuli, the internal and behavioral responses are different.
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Artist David Lyons and computer scientist David Flatla work collaboratively to create art that intentionally targets audiences of varying visual abilities mediated through smart device interfaces. Conceived as an investigation into theories and practices of visual perception, they explore the idea that artwork can be intentionally created to be experienced differently dependent on one’s visual abilities. They have created motion graphics and supporting recolouring and colour vision deficiency (CVD) simulation software. Some of the motion graphics communicate details specifically to those with colour blindness/CVD by containing moving imagery only seen by those with CVD. Others will contain moving images that those with typical colour vision can experience but appear to be unchanging to people with CVD. All the artwork is revealed for both audiences through the use of specially programmed smart devices, fitted with augmented reality recolouring and CVD simulation software. The visual elements come from various sources, including the Ishihara Colour Blind Test, movie marques, and game shows. The software created reflects the perceptual capabilities of most individuals with reduced colour vision. The development of the simulation software and the motion graphic series are examined and discussed from both computer science and artistic positions.
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Weekly Newsletter from the Northwest District Office for libraries containing programs, activities, classes for the upcoming week.
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Weekly Newsletter from the Northwest District Office for libraries containing programs, activities, classes for the upcoming week.
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Weekly Newsletter from the Northwest District Office for libraries containing programs, activities, classes for the upcoming week.
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Weekly Newsletter from the Northwest District Office for libraries containing programs, activities, classes for the upcoming week.