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Arenas Mejía, Catherine, i Ingrid Sulay Tavera Perez. "Validez del cuestionario CISS-V15 para el diagnóstico de la insuficiencia de convergencia". Revista Investigación en Salud Universidad de Boyacá 3, nr 2 (1.12.2016): 127. http://dx.doi.org/10.24267/23897325.183.
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Introducci.n. El cuestionario Convergence Insufficiency Symptoms Survey, (CISSV15)es una herramienta para el diagn.stico y seguimiento del tratamiento depacientes con insuficiencia de convergencia.Objetivo. Determinar la validez del cuestionario CISS-V15 para el diagn.stico de lainsuficiencia de convergencia, frente a las pruebas cl.nicas con que se eval.a elestado motor ocular de los pacientes atendidos en consulta optom.trica, en lasciudades de Recife y Salvador, Brasil.M.todos. Se llev. a cabo un estudio con enfoque cuantitativo, de tipo transversal ydescriptivo, con 50 pacientes de dos instituciones educativas en Brasil. Seseleccionaron aquellos que cumpl.an con los criterios de inclusi.n para aplicar elcuestionario, y se identificaron los pacientes con insuficiencia de convergencia yaquellos con visi.n binocular normal. Se analizaron los resultados del cuestionarioy las pruebas de motilidad ocular, para estimar medidas de tendencia central, yanalizar los valores de sensibilidad y especificidad del cuestionario.Resultados. La prueba alcanz. una sensibilidad de 0,83 y una especificidad de0,81.Conclusiones. Frente a las pruebas cl.nicas, el cuestionario CISS-V15 demostr.tener validez diagn.stica para las personas con insuficiencia de convergencia yaquellas con visi.n binocular normal, lo que lo convierte en una herramienta valiosapara el diagn.stico y seguimiento del tratamiento de los pacientes con insuficienciade convergencia.Palabras clave: trastornos de la motilidad ocular, visi.n binocular, astenopia,diplop.a, validez de las pruebas
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Brenner, Eli, i Wim J. M. Van Damme. "Judging distance from ocular convergence". Vision Research 38, nr 4 (luty 1998): 493–98. http://dx.doi.org/10.1016/s0042-6989(97)00236-8.
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Mays, L. E., Y. Zhang, M. H. Thorstad i P. D. Gamlin. "Trochlear unit activity during ocular convergence". Journal of Neurophysiology 65, nr 6 (1.06.1991): 1484–91. http://dx.doi.org/10.1152/jn.1991.65.6.1484.
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1. Ocular convergence is usually accompanied by excyclotorsion of the eyes. Furthermore, the magnitude of cyclotorsion is dependent on the elevation of the eyes. The reason for this excyclotorsion during convergence is not understood. 2. Excyclotorsion could be produced by either increased activity in the inferior oblique muscle or decreased activity in the superior oblique muscle. An earlier study indicated that convergence may also be accompanied by a temporal (lateral) translation of the eye. This observation is more consistent with a relaxation of the superior oblique than contraction of the inferior oblique. 3. This hypothesis was tested by recording the activity of 31 neurons in the trochlear nucleus, which contains the superior oblique motoneurons. This was done in alert monkeys that were trained to make both versional and vergence eye movements. In addition, the cyclotorsion associated with convergence was measured in one of these monkeys. 4. A consistent excyclotorsion associated with convergence was observed. Trochlear unit activity decreased during convergence in all cells tested. The magnitude of this decrease was significantly greater than that seen with conjugate adduction. Furthermore, the size of the decrease varied systematically with ocular elevation in a manner that was consistent with earlier measures of cyclotorsion during convergence. 5. These results suggest that the excyclotorsion seen during convergence, and perhaps the lateral translation of the eye, are due to a relaxation of the superior oblique muscle. This relaxation during convergence is greater than that which accompanies similar conjugate movements of the eyes. We hypothesize that this peculiar pattern of muscle innervation has a motor rather than sensory function.(ABSTRACT TRUNCATED AT 250 WORDS)
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Carbone, Mauro. "La surface obscure". Chiasmi International 21 (2019): 103–15. http://dx.doi.org/10.5840/chiasmi20192114.
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Tout le trajet de la pensée de Merleau-Ponty est traversé – en certains cas de manière plus évidente que d’autres – par ce que je propose de définir comme une idée de la littérature et de la philosophie en tant que dispositifs de vision, pour utiliser une expression qui est née – et ce n’est pas un hasard – dans le domaine des études cinématographiques. Plus précisément, je voudrais montrer que Merleau-Ponty voit la littérature et la philosophie de son époque opérer comme des dispositifs de vision convergents, vision qui est à considérer, à son tour, comme une pratique corporelle et pas seulement oculaire. Cela dit, il faut souligner que de tels dispositifs visuels convergents ont la particularité de fonctionner avec les mots, et que Merleau-Ponty met l’accent sur leur différente efficacité à exprimer son époque. De plus, je pense que l’idée implicite de la philosophie en tant que dispositif de vision opérant par des mots « comme toute la littérature » a une place importante, mais pour l’instant pas assez développée, dans la dernière période de la pensée de Merleau-Ponty. En outre, je voudrais souligner qu’une telle perspective est cruciale aussi pour notre époque, bien que je crois qu’elle soit différente de celle de Merleau-Ponty. En effet, je pense que notre époque et celle de Merleau-Ponty sont toutes deux caractérisées par une tension entre l’importance croissante des images et la centralité traditionnelle du concept dans notre culture.The whole path of Merleau-Ponty’s thought is crossed – some times more evidently than others – by what I propose to qualify as the idea of literature and philosophy as visual apparatuses (dispositifs), to use an expression that was born – and not by chance – in the field of Film Studies. More precisely, I aim at asserting that Merleau-Ponty sees literature and philosophy working in his epoch as convergent apparatuses of vision, in turn understood as a bodily and not merely ocular practice. Immediately after that, I should specify that such convergent visual apparatuses peculiarly function by words, and that Merleau-Ponty stresses their different efficiency in expressing his epoch.Moreover, I think that the implicit idea of philosophy as a visual apparatus working by words “like all literature” has a particularly relevant but so far not consequently developed place in in the last period of Merleau-Ponty’s thought. Also, I would like to stress that such a perspective is crucial in our own time too, even though I consider it to be different from Merleau-Ponty’s. Indeed, I think that both our time and Merleau-Ponty’s are characterized by a tension between the increasing importance of images and the traditional centrality of the concept in our culture.L’intero percorso del pensiero di Merleau-Ponty è attraversato, in certi casi in modo più evidente, da quella che propongo di definire come un’idea di letteratura e di filosofia come dispositivi di visione, per usare un’espressione nata, non a caso, nell’ambito dei Film Studies. Più precisamente, vorrei mostrare come Merleau-Ponty concepisca la letteratura e la filosofia della sua epoca come dispositivi di visione convergenti, intesi come una pratica corporea e non già meramente ottica. Specificherò, poi, che tali dispositivi di visione convergenti operano attraverso la parola e che Merleau-Ponty sottolinea la loro diversa efficacia nell’esprimere la sua epoca. Ritengo inoltre che l’idea implicita di filosofia come dispositivo di visione che agisce tramite la parola, “come tutta la letteratura”, occupi un posto particolarmente decisivo, anche se non del tutto esplicitato, nell’ultimo periodo del pensiero di Merleau-Ponty. Vorrei poi mostrare come tale prospettiva si riveli cruciale anche nel nostro tempo, per quanto diverso rispetto a quello di Merleau-Ponty. Infatti, penso che tanto la nostra epoca quanto quella di Merleau-Ponty siano caratterizzate da una tensione tra l’importanza sempre crescente delle immagini e la tradizionale centralità riservata al concetto nella nostra cultura.
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Monaco, A., O. Streni, M. Marci, L. Sabetti, G. Marzo i M. Giannoni. "Relationship between mandibular deviation and ocular convergence". Journal of Clinical Pediatric Dentistry 28, nr 2 (1.01.2005): 135–38. http://dx.doi.org/10.17796/jcpd.28.2.mj7311l03m257134.
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Recent studies have confirmed the relationship between head posture, mandibular position and visual focusing. A case-controlled study was conducted to assess the occurrence of ocular convergence defects between subjects with functional mandibular latero-deviation and healthy subjects in pediatric age. Sixty subjects (the study group) presented mandibular latero-deviation classified as functional according to the use of a clinical examination and frontal and basal tele-radiography. Sixty subjects without functional mandibular laterodeviation (control group) were selected randomly from all subjects seeking pediatric dental care and matched by gender and age to study group. All one hundred and twenty subjects were submitted to orthoptic tests performed by the same operator. These results seemed to confirm that in mandibular latero-deviation subjects ocular convergence defects occurred in greater frequency than in controls underlining the importance of role of pediatric dentistry among interdisciplinary cooperation.
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Saji, Juhi, Muhemmed Swadique i Ravi RV. "Study of ocular causes of convergence insufficiency". MedPulse International Journal of Ophthalmology 12, nr 1 (2019): 14–16. http://dx.doi.org/10.26611/100941214.
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Lê, Thanh-Thuan, i Zoï Kapoula. "Role of ocular convergence in the Romberg quotient". Gait & Posture 27, nr 3 (kwiecień 2008): 493–500. http://dx.doi.org/10.1016/j.gaitpost.2007.06.003.
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Burkhart, Scott O., Christine Ellis i Troy M. Smurawa. "VESTIBULAR AND OCULAR MOTOR FINDINGS IN ACUTELY INJURED 8-12-YEAR-OLD PATIENTS FOLLOWING CONCUSSION". Orthopaedic Journal of Sports Medicine 7, nr 3_suppl (1.03.2019): 2325967119S0000. http://dx.doi.org/10.1177/2325967119s00005.
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Background: Vestibular and ocular motor deficits have been recognized as a key marker of the pathophysiology consistent with the diagnosis of concussion (Grady, 2010). Previous studies have been performed detailing the validity and clinical benefit of vestibular and ocular motor assessments (Corwin et al., 2015; Mucha et al., 2014). Recent guidelines and position statements have started recommending the use of vestibular and ocular motor assessment for pediatric patients (Matuszak et al., 2016), the most recent consensus statement recommending vestibular and ocular motor assessment by all practitioners within acute concussion settings (McCrory et al., 2017). Unfortunately, very little data exists with respect to vestibular and ocular motor performance in concussion patients between 8-12 years of age. The current study included a standardized administration of the Vestibular Ocular Motor Screening (VOMS) and the King-Devick Test (KD) in a sample of patients diagnosed with concussion and evaluated in an outpatient concussion clinic within 7 days of their initial date of injury. This study intended to evaluate performance on the VOMS and KD in an injured sample of patients 8-12 years of age. Methods: Pediatric patients diagnosed with concussion (n = 45) presenting to an outpatient concussion clinic within 7 days from their initial date of injury were administered a standardized version of the VOMS and KD. Patients were administered the VOMS and KD by certified athletic trainers educated and trained on administration. The VOMS consists of nine measures and was validated by the University of Pittsburgh (Mucha et al., 2014) as a symptom provocation measure with a symptom rating of 0-10 with convergence measured in centimeters, and scores of 6 cm or greater being indicative of abnormal. The KD is an ocular motor performance measure and has previously demonstrated reliability, sensitivity and specificity with respect to concussion diagnosis (Hecimovich et al., 2018). Demographic, acute injury, and baseline values were summarized using descriptive statistics. Point estimates and 95% confidence intervals were calculated for all end points. Pearson correlations were calculated based numerical values from the VOMS and KD data. Results: The total sample consisted of 14 females and 31 males, with a mean age of 10.6 + 1.4 years. 20% of the subjects (n = 9) reported a prior history of concussion with a total of 17 previous concussions reported. 13.3% of the sample (n = 6) reported a history of migraine and 4.4% (n = 2) reported a history of psychiatric diagnosis. Acute self-reported injury data based on signs and symptom markers were calculated including; dizziness (66.6%, n = 30), headache (82.2%, n = 37), vision problems (42.2%, n = 19), amnesia (35.5%, n = 16), and loss of consciousness (22.2%, n = 10). Descriptive statistics for baseline VOMS symptoms were recorded; headache (mean = 3.2 + 2.7, CI = 2.8-3.6), dizziness (mean = 1.3 + 1.7, CI = 1.1 -1.5) nausea (mean = 0.7 + 1.6, CI = 0.5-0.9), and fogginess (mean = 1.1 + 2.0, CI = 0.8 -1.4). VOMS convergence in centimeters across trials; T1 (mean = 5.1 + 5.2, CI = 4.6-5.9), T2 (mean = 6.2 + 5.8, CI = 5.3-7.1), and T3 (mean = 7.1 + 6.9, CI = 6.1-8.1). KD time in seconds; card 1 (mean = 22.4 + 9.5, CI = 21-23.8), card 2 (mean = 23.1 + 9.5, CI = 21.7-24.5), card 3 (mean = 27.2 + 9.3, CI = 25.8-28.6), and total (mean = 72.8 + 27.3, CI = 68.7-76.9). Pearson correlations revealed strong correlations across VOMS symptoms; headache (r = 0.89-0.99), dizziness (r = 0.78-0.98), nausea (r = 0.88-0.98), and fogginess (r = 0.89-0.98). Moderate correlations between KD time and convergence distance were observed; KD card 1 (convergence T1, r = 0.61, convergence T2, r = 0.58, convergence T3, r = 0.49), KD card 2 (convergence T1, r = 0.62, convergence T2, r = 0.58, convergence T3, r = 0.48), and KD total time (convergence T1, r = 0.59, convergence T2, r = 0.54, convergence T3, r = 0.46). Conclusion: To the best knowledge of the authors involved, this study is the first of its kind to explore the performance on the VOMS and KD in a sample of acutely injured (< 7 days) 8-12-year-old patients diagnosed with concussion. Several notable findings were observed. Headache was the most predominant symptom reported during VOMS administration and remained significantly higher than the other symptoms of dizziness, nausea, and fogginess. This finding may be the byproduct of increased difficulty in symptom description between the ages of 8-12. Further, correlations within symptoms were strong suggesting throughout VOMS administration symptoms remain relatively stable. Lastly, moderate relationships were noted between convergence on the VOMS and KD time scores. This is likely a result of both measures addressing ocular motor functioning but differing based on data medium (centimeters versus seconds). The current study was limited based on sample size and further data is necessary to draw larger conclusions based on 8-12-year-old injured VOMS and KD performance.
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Gamlin, P. D., J. W. Gnadt i L. E. Mays. "Abducens internuclear neurons carry an inappropriate signal for ocular convergence". Journal of Neurophysiology 62, nr 1 (1.07.1989): 70–81. http://dx.doi.org/10.1152/jn.1989.62.1.70.
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1. Single-unit recording studies in alert Rhesus monkeys characterized the vergence signal carried by abducens internuclear neurons. These cells were identified by antidromic activation and the collision of spontaneous with antidromic action potentials. The behavior of abducens internuclear neurons during vergence was compared with that of horizontal burst-tonic fibers in the medial longitudinal fasciculus (MLF) and to that of a large sample of unidentified abducens cells (presumably both motoneurons and internuclear neurons). 2. The results indicate that abducens internuclear neurons and lateral rectus motoneurons behave similarly during vergence eye movements: the majority of both groups of cells decrease their firing rate for convergence eye movements: a minority show no change for vergence. This finding is strongly supported by recordings of horizontal burst-tonic fibers in the MLF, the majority of which decrease their activity significantly for convergence eye movements. 3. These findings indicate that a net inappropriate vergence signal is sent to medial rectus motoneurons via the abducens internuclear pathway. Because medial rectus motoneurons increase their activity appropriately during symmetrical convergence, this inappropriate MLF signal must be overcome by a more potent direct vergence input. 4. Overall, both abducens internuclear neurons and lateral rectus motoneurons decrease their activity for convergence less than would be expected based on their conjugate gain. This implies that some degree of co-contraction of the lateral and medial rectus muscles occurs during convergence eye movements. 5. Some horizontal burst-tonic MLF fibers decrease their activity more for convergence than any recorded abducens neuron. These fibers may arise from cells in the nucleus prepositus hypoglossi or vestibular nuclei.
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Takada, Ritsuko, Naoto Hara, Hiruma Hasebe, Haruo Toda, Mineo Takagi, Haruki Abe i Takehiko Bando. "1541 Effects of extrastriate cortical lesions on ocular convergence". Neuroscience Research 28 (styczeń 1997): S194. http://dx.doi.org/10.1016/s0168-0102(97)90529-0.
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Oyamada, H., H. Hasebe, S. Kinomura, R. Kawashima, Y. Ouchi, R. Takada, H. Tsukada i in. "1542 Ocular convergence to disparity stimuli-a pet study". Neuroscience Research 28 (styczeń 1997): S194. http://dx.doi.org/10.1016/s0168-0102(97)90530-7.
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Ooi, D., E. D. Cornell, I. S. Curthoys, A. M. Burgess i H. G. MacDougall. "Convergence reduces ocular counterroll (OCR) during static roll-tilt". Vision Research 44, nr 24 (listopad 2004): 2825–33. http://dx.doi.org/10.1016/j.visres.2004.06.014.
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Scarfe, Peter, i Paul Hibbard. "A Bayesian model of distance perception from ocular convergence". Journal of Vision 17, nr 10 (31.08.2017): 159. http://dx.doi.org/10.1167/17.10.159.
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Mansour, Ahmad M., Frederick Wang, Fadi El-Baba i Paul Henkind. "Ocular Complications in Strabismus fîxus convergens". Ophthalmologica 195, nr 3 (1987): 161–66. http://dx.doi.org/10.1159/000309806.
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Miller, Joel M., Ryan C. Davison i Paul D. Gamlin. "Motor nucleus activity fails to predict extraocular muscle forces in ocular convergence". Journal of Neurophysiology 105, nr 6 (czerwiec 2011): 2863–73. http://dx.doi.org/10.1152/jn.00935.2010.
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For a given eye position, firing rates of abducens neurons (ABNs) generally ( Mays et al. 1984 ), and lateral rectus (LR) motoneurons (MNs) in particular ( Gamlin et al. 1989a ), are higher in converged gaze than when convergence is relaxed, whereas LR and medial rectus (MR) muscle forces are slightly lower ( Miller et al. 2002 ). Here, we confirm this finding for ABNs, report a similarly paradoxical finding for neurons in the MR subdivision of the oculomotor nucleus (MRNs), and, for the first time, simultaneously confirm the opposing sides of these paradoxes by recording physiological LR and MR forces. Four trained rhesus monkeys with binocular eye coils and custom muscle force transducers on the horizontal recti of one eye fixated near and far targets, making conjugate saccades and symmetric and asymmetric vergence movements of 16–27°. Consistent with earlier findings, we found in 44 ABNs that the slope of the rate-position relationship for symmetric vergence ( kV) was lower than that for conjugate movement ( kC) at distance, i.e., mean kV/ kC = 0.50, which implies stronger LR innervation in convergence. We also found in 39 MRNs that mean kV/ kC = 1.53, implying stronger MR innervation in convergence as well. Despite there being stronger innervation in convergence at a given eye position, we found both LR and MR muscle forces to be slightly lower in convergence, −0.40 and −0.20 g, respectively. We conclude that the relationship of ensemble MN activity to total oculorotary muscle force is different in converged gaze than when convergence is relaxed. We conjecture that LRMNs with kV < kC and MRMNs with kV > kC innervate muscle fibers that are weak, have mechanical coupling that attenuates their effective oculorotary force, or serve some nonoculorotary, regulatory function.
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Miller, Joel M., Christopher J. Bockisch i Dmitri S. Pavlovski. "Missing Lateral Rectus Force and Absence of Medial Rectus Co-Contraction in Ocular Convergence". Journal of Neurophysiology 87, nr 5 (1.05.2002): 2421–33. http://dx.doi.org/10.1152/jn.00566.2001.
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For a given position of the eye in the orbit, most abducens motoneurons (LRMNs) fire at higher rates in converged gaze than when convergence is relaxed, implying that lateral rectus (LR) muscle force will be higher for a given eye position in convergence. If medial rectus (MR) muscle force balances LR force, it too would be higher in convergence, that is, LRMN recording studies predict horizontal rectus co-contraction in convergence. Three trained rhesus monkeys with binocular eye coils and custom muscle force transducers (MFTs) on LR and MR of one eye alternately fixated near (approximately 7 cm) and far (200 cm) targets with vergence movements of 20–30°. Tonic muscle forces were also measured during conjugate fixation of far targets over a 30 × 30° field. MFT characteristics and effects on oculomotility were assessed. Contrary to predictions, we found small (<1 g) decreases in both LR and MR forces in convergence, for those gaze positions that were used in the brain stem recording studies. This missing LR forceparadox (higher LRMN firing rates in convergence but lower LR forces) suggests that motoneurons or muscle fibers contribute differently to oculorotary forces in converged and unconverged states, violating the final common path hypothesis. The absence of MR co-contraction is consistent with, and supports, the missing LR force finding. Resolution of the missing LR force paradox might involve nonlinear interactions among muscle fibers, mechanical specialization of muscle fibers and other articulations of the peripheral oculomotor apparatus, or extranuclear contributions to muscle innervation.
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Lee, Ji-Woo, Hyun Gug Cho, Byeong-Yeon Moon, Sang-Yeob Kim i Dong-Sik Yu. "Effects of prolonged continuous computer gaming on physical and ocular symptoms and binocular vision functions in young healthy individuals". PeerJ 7 (4.06.2019): e7050. http://dx.doi.org/10.7717/peerj.7050.
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Background and Objective Addiction to computer gaming has become a social problem in Korea and elsewhere, and it has been enlisted as a mental health disorder by the World Health Organization. Most studies related to computer use and vision have individually assessed physical and ocular symptoms and binocular vision. Accordingly, the present study comprehensively assessed subjective physical and ocular symptoms and functions related to binocular vision after prolonged continuous computer gaming. This study aimed to investigate the effects of prolonged continuous computer gaming on physical and ocular health and visual functions in young healthy individuals. Methods Fifty healthy college students (35 male/15 female), aged 19–35 years old, were enrolled in this study. The inclusion criteria were no binocular vision problems and no reported history of ocular disease. Participants played continuously for 4 h from 6:00 to 10:00 p.m. Physical and ocular symptoms and visual functions such as convergence, accommodation, phoria, and the blink rate were assessed before and after continuous computer gaming for 4 h. Results Continuous computer gaming for 4 h resulted in convergence and accommodation disturbances and increased physical and ocular discomfort. Near phoria showed an exophoric shift, whereas distance phoria showed no change. Moreover, the accommodative and vergence facilities and blink rate were significantly decreased. All visual functions recovered to the baseline levels by the following morning. Discussion Our findings suggest that excessive and continuous computer gaming impairs visual functions and causes ocular and physical fatigue. Our findings further the understanding of the adverse effects of excessive computer use on physical and ocular health, and adequate breaks are necessary to reduce physical and visual discomfort during computer gaming.
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Wu, Yidong, Meiping Xu, Junxiao Zhang, Jinjing Zhou, Minghui Wan, Zhiyue Dai, Tingting Peng i in. "Can Clinical Measures of Postoperative Binocular Function Predict the Long-Term Stability of Postoperative Alignment in Intermittent Exotropia?" Journal of Ophthalmology 2020 (21.07.2020): 1–9. http://dx.doi.org/10.1155/2020/7392165.
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Purpose. To evaluate whether clinical measures of postoperative binocular functions could predict the long-term stability of postoperative ocular alignment in children with intermittent exotropia. Methods. A retrospective study was performed in thirty-nine children (median: 7 years) who have been surgically treated from intermittent exotropia without overcorrection (less than 10 prism diopters [pd] of exodeviation at 1 month postoperatively). Angles of deviation and binocular functions were measured preoperatively and at 1 month, 6 months, and the final follow-up visit (≥24 months) postoperatively. We examined the relationships between postoperative drift (change of ocular alignment) and binocular functions (sensory fusion, fusional convergence amplitude, and stereoacuity). Results. The surgical success rate (esophoria/tropia ≤5 pd to exophoria/tropia ≤10 pd) dropped to 76.9% at 6 months after surgery and to 53.8% at individuals’ last visit (mean: 37 months). The mean exodrift was 7.7 ± 9.2 pd from the postoperative month 1 to the final visit (p<0.001) on distance fixation. Distance stereoacuity, central fusion, and fusional convergence amplitude significantly improved following surgery (p<0.05). However, no significant correlation was found between their binocular functions measured at the beginning of each follow-up period and the postoperative drift (all p>0.13). Conclusion. Our findings suggest that the clinical measures of sensory fusion, fusional convergence amplitude, and stereoacuity cannot serve as a robust predictor for the long-term stability of postoperative ocular alignment in patients who underwent successful surgery without overcorrection at 1 month postoperatively.
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Takagi, Mineo, Haruo Toda i Takehiko Bando. "Extrastriate cortical neurons correlated with ocular convergence in the cat". Neuroscience Research 17, nr 2 (lipiec 1993): 141–58. http://dx.doi.org/10.1016/0168-0102(93)90091-4.
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Burkhart, Scott O., Christine Ellis i Troy M. Smurawa. "ACUTE PERFORMANCE ON A VESTIBULAR AND OCULAR MOTOR SCREENER AND RECOVERY FOLLOWING CONCUSSION". Orthopaedic Journal of Sports Medicine 7, nr 3_suppl (1.03.2019): 2325967119S0013. http://dx.doi.org/10.1177/2325967119s00136.
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Background: Concussion injuries are synonymous with vestibular impairments and symptoms include dizziness, impaired balance, and problems with gaze stability (Covassin et al., 2014). Common ocular motor impairments after a concussion include convergence/accommodative insufficiencies and saccadic dysfunction (Mucha et al., 2014). Vestibular and ocular motor impairments have been linked to worse outcomes following concussion (Pearce et al., 2015), including prolonged recovery (Corwin et al., 2015). The purpose of the current study was to determine which VOMS impairments were linked with longer recovery. Methods: Pediatric patients diagnosed with concussion (n = 131) presenting to an outpatient concussion clinic within 7 days from their initial date of injury were administered a standardized version of the VOMS. Patients were administered the VOMS by certified athletic trainers educated and trained on administration. The VOMS consists of nine measures and was validated by the University of Pittsburgh (Mucha et al., 2014) as a symptom provocation measure with a symptom rating of 0-10 with convergence measured in centimeters, and scores of 6 cm or greater being indicative of abnormal. Demographic, acute injury, and baseline values were summarized using descriptive statistics. Point estimates and 95% confidence intervals were calculated for all end points. Results: 131 patients with a mean age of 13.5 + 2.4 completed the VOMS within 7 days (mean = 3.2 + 1.7) of a diagnosed concussion. The sample was evenly divided by gender (52.7% male, 47.3% female). Patients were grouped by recovery time: <14 days (n = 19, 14.5%) 15-28 days (n = 64, 48.9%), and 29-120 days (n = 48, 36.6%). In the <14 day recovery group, 5.2% (n = 2) reported a history of concussion, 15.8% (n = 3) reported a history of migraine, and 5.2% (n = 2) reported a history of psychiatric diagnosis. In the 15-28 day recovery group, 21.9% (n = 14) reported a history of concussion, 9.4% (n = 6) reported a history of migraine, and 6.5% (n = 4) reported a history of psychiatric diagnosis. In the 29-120 day recovery group, 25% (n = 12) reported a history of concussion, 25% (n = 12) reported a history of migraine, and 6.25% (n = 3) reported a history of psychiatric diagnosis. Descriptive statistics for baseline VOMS symptoms were recorded for the <14 day recovery group; headache (mean = 1 + 1.49, CI = 0.7 -1.3), dizziness (mean = 0.2 + 0.5, CI = 0.1-0.3), nausea (mean = 0 + 0, CI = 0-0), and fogginess (mean = 0.9 + 1.5, CI = 0.5 -1.3), for the 15-28 day recovery group; headache (mean = 3.3 + 2.4, CI = 3-3.6), dizziness (mean = 1.5 + 1.9, CI = 1.3 -1.7), nausea (mean = 0.8 + 1.7, CI = 0.6 -1), and fogginess (mean = 1.7 + 2.2, CI = 1.4-2), for the 29-120 day recovery group; headache (mean = 4.4 + 2.2, CI = 4.1-4.7), dizziness (mean = 1.9 + 2.2, CI = 1.6-2.2), nausea (mean = 1.4 + 2.2, CI = 1.1 -1.7), and fogginess (mean = 2.4 + 2.9, CI = 2-2.8). VOMS convergence in centimeters across trials for the <14 day recovery group; T1 (mean = 2.6 + 2.4, CI = 2.1-3.1), T2 (mean = 3.4 + 2.4, CI = 2.9-3.9), and T3 (mean = 3.8 + 2.5, CI = 3.2-4.4), for the 15-29 day recovery group; T1 (mean = 3.9 + 3.9, CI = 3.4-4.4), T2 (mean = 4.8 + 4.2, CI = 4.3-5.3), and T3 (mean = 5.3 + 5.1, CI = 4.7-5.9), for the 29-120 day recovery group; T1 (mean = 6.9 + 5.2, CI = 6.1-7.7), T2 (mean = 8.3 + 1.8, CI = 7.4-9.2), and T3 (mean = 9.6 + 2.1, CI = 8.6-10.6). VOMS symptom provocation increase of +2 and +3 from baseline were totaled for each recovery group. Abnormal convergence greater than 6 cm on any trial was totaled for each group. Percentages for all 3 recovery groups with symptom provocation of +2, +3, and abnormal convergence were calculated. In the <14 day recovery group, 21% had a +2 symptom provocation on at least one symptom, 16% had a +3 symptom increase on at least one symptom, and 16% had abnormal convergence greater than 6 cm on at least one convergence trial. 11% of the <14 day recovery group had a +2, +3, increase and abnormal convergence greater than 6 cm. In the 15-29 day recovery group, 69% had a +2 symptom provocation on at least one symptom, 34% had a +3 symptom increase on at least one symptom, and 38% had abnormal convergence greater than 6 cm on at least one convergence trial. 13% of the 15-29 day recovery group had a +2, +3, increase and abnormal convergence greater than 6 cm. In the 29-120 day recovery group, 85% had a +2 symptom provocation on at least one symptom, 60% had a +3 symptom increase on at least one symptom, and 58% had abnormal convergence greater than 6 cm on at least one convergence trial. 38% of the 29-120 day recovery group had a +2, +3, increase and abnormal convergence greater than 6 cm. Conclusion: The current study identified symptom provocation of +2 and +3 as well as abnormal convergence greater than 6 cm were the most synonymous with recovery across the three recovery groups. Clinicians should consider these findings in providing recommendations and discussing anticipated recovery with patients. Further research is needed to determine more definitive parameters when predicting recovery following concussion.
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Demer, Joseph L., i Robert A. Clark. "Magnetic resonance imaging of differential compartmental function of horizontal rectus extraocular muscles during conjugate and converged ocular adduction". Journal of Neurophysiology 112, nr 4 (15.08.2014): 845–55. http://dx.doi.org/10.1152/jn.00649.2013.
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Activity in horizontal rectus extraocular muscles (EOMs) was investigated by magnetic resonance imaging (MRI) of humans during asymmetric convergence to a monocularly aligned target at 15-cm distance or monocular fixation of afocal targets placed over a wide range of conjugate abduction through adduction. Cross sections and posterior partial volumes (PPVs) of EOMs were determined from quasi-coronal image planes and were separately analyzed in the inferior vs. superior compartments, defined by lines bisecting their maximum vertical dimensions. Both inferior and superior compartments of medial (MR) and lateral (LR) rectus exhibited contractile changes in PPV and maximum cross section for both asymmetric convergence and a comparable range of conjugate adduction. Both LR compartments, and the inferior MR compartment, exhibited similar decreases in contractility correlating with relaxation during both convergence and conjugate adduction. In contrast, the superior MR compartment exhibited roughly three times the contractility in conjugate adduction as in similar-magnitude convergence. In the aligned eye that did not move during convergence, summed contractility in all compartments of MR and LR exhibited corelaxation consistent with published EOM force measurements in this paradigm (Miller JM, Bockisch CJ, Pavlovski DS. J Neurophysiol 87: 2421–2433, 2002; Miller JM, Davison RC, Gamlin PD. J Neurophysiol 105: 2863–2873, 2011). The superior MR compartment also exhibited significantly greater contractility than the other compartments over the maximum achievable horizontal globe rotation from abduction to adduction. These findings suggest that the superior MR compartment is controlled differentially from the inferior compartment and suggest that its activity is reduced during convergence as a component of generally altered extraocular mechanics.
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Moran, Ryan N., Tracey Covassin i Jessica Wallace. "Premorbid migraine history as a risk factor for vestibular and oculomotor baseline concussion assessment in pediatric athletes". Journal of Neurosurgery: Pediatrics 23, nr 4 (kwiecień 2019): 465–70. http://dx.doi.org/10.3171/2018.10.peds18425.
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OBJECTIVEMigraine history has recently been identified as a risk factor for concussion and recovery. The authors performed a cross-sectional study examining baseline outcome measures on newly developed and implemented concussion assessment tools in pediatrics. The purpose of this study was to examine the effects of premorbid, diagnosed migraine headaches as a risk factor on vestibular and oculomotor baseline assessment in pediatric athletes.METHODSPediatric athletes between the ages of 8 and 14 years with a diagnosed history of migraine headache (n = 28) and matched controls without a history of diagnosed migraine headache (n = 28) were administered a baseline concussion assessment battery, consisting of the Vestibular/Ocular Motor Screening (VOMS), near point of convergence (NPC), and the King-Devick (K-D) tests. Between-groups comparisons were performed for vestibular symptoms and provocation scores on the VOMS (smooth pursuit, saccades, convergence, vestibular/ocular reflex, visual motion sensitivity), NPC (average distance), and K-D (time).RESULTSIndividuals diagnosed with migraine headaches reported greater VOMS smooth pursuit scores (p = 0.02), convergence scores (p = 0.04), vestibular ocular reflex scores (p value range 0.002–0.04), and visual motion sensitivity scores (p = 0.009). Differences were also observed on K-D oculomotor performance with worse times in those diagnosed with migraine headache (p = 0.02). No differences were reported on NPC distance (p = 0.06) or headache symptom reporting (p = 0.07) prior to the VOMS assessment.CONCLUSIONSPediatric athletes diagnosed with migraine headaches reported higher baseline symptom provocation scores on the VOMS. Athletes with migraine headaches also performed worse on the K-D test, further illustrating the influence of premorbid migraine headaches as a risk factor for elevated concussion assessment outcomes at baseline. Special consideration may be warranted for post-concussion assessment in athletes with migraine headaches.
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Figueroa O., Luisa Fernanda, i Yolanda López Aguirre. "Estrabismos convergentes y divergentes en niños". Ciencia & Tecnología para la Salud Visual y Ocular 8, nr 2 (1.12.2010): 103–14. http://dx.doi.org/10.19052/sv.819.
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En la valoración visual del paciente pediátrico es indispensable determinar el alineamiento ocular, para poder así descartar estrabismos que generan además de ambliopía, pérdida de la visión binocular. La endotropia se considera como el tipo más frecuente de estrabismo en los niños, responsable de más del 50% de las desviaciones, cuyo manejo puede ser quirúrgico o con prescripción óptica de acuerdo a su origen. Las exodesviaciónes son poco frecuentes antes de los 6 meses, generalmente inician de manera intermitente y se vuelven constantes, están asociadas a insuficiencia de convergencia y correspondencia sensorial anómala; dependiendo de su magnitud y permanencia se tratan con ortóptica o con cirugía.
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Gupta, Akanksha, Pallavi Mohanty i Sonika Bhatnagar. "Integrative analysis of ocular complications in atherosclerosis unveils pathway convergence and crosstalk". Journal of Receptors and Signal Transduction 35, nr 2 (23.07.2014): 149–64. http://dx.doi.org/10.3109/10799893.2014.942462.
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Kawata, Keisuke, Leah H. Rubin, Jong Hyun Lee, Thomas Sim, Masahiro Takahagi, Victor Szwanki, Al Bellamy i in. "Association of Football Subconcussive Head Impacts With Ocular Near Point of Convergence". JAMA Ophthalmology 134, nr 7 (1.07.2016): 763. http://dx.doi.org/10.1001/jamaophthalmol.2016.1085.
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Sherpa, D. "Ocular morbidity among primary school children". Journal of Chitwan Medical College 4, nr 2 (30.07.2014): 32–34. http://dx.doi.org/10.3126/jcmc.v4i2.10860.
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Knowledge of disease pattern in children can help design preventive and curative strategies. This study is conducted to determine the pattern of ocular morbidity among the primary school children. Children of primary school were included in this study. A complete eye examination was done in all children including loupe examination, refraction and Perkins tonometry. funduscopy were done in selected children. A total of 332 primary school children were included in the study, of which 332 children 99 (29.82 %) had ocular morbidity. Refractive error was the commonest type of ocular morbidity in 31 (9.33 %). Myopia was the commonest type of refractive error (84.77%) in contrast to hypermetropia (0.30 %). 27. Conjunctivitis was the second common type of ocular morbidity (17%). Among others, Convergence insufficiency in 17 children (5.12%), exodeviation in 10 children (3.01%), blepharitis in 5 children (1.5%), vitamin A deficiency in 5 children (1.50%), ocular trauma in 2 patients (0.60%) and stye in 2 children (0.60%) were found. Refractive error is the commonest form of ocular morbidity in primary school children. DOI: http://dx.doi.org/10.3126/jcmc.v4i2.10860 Journal of Chitwan Medical College 2014; 4(2): 32-34
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Frohman, Elliot M., Richard B. Dewey i Teresa C. Frohman. "An unusual variant of the dorsal midbrain syndrome in MS: clinical characteristics and pathophysiologic mechanisms". Multiple Sclerosis Journal 10, nr 3 (czerwiec 2004): 322–25. http://dx.doi.org/10.1191/1352458504ms1043oa.
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Patients with MS exhibit a broad diversity of ocular motor syndromes. We describe a patient with relapsing-remitting MS who developed an unusual variation of the dorsal midbrain syndrome, character ized by monocular convergent-retraction nystagmus in the right eye, accompanied by divergent-retraction nystagmus in the fellow eye upon attempted upward gaze. Examination also revealed a skew deviation with a left hyperdeviation and severe adductio n limitation in the left eye during attempted right gaze. We propose that a left INO accounted for the inability of the left eye to adduct (and result in convergent-retraction) during attempted upward saccades. We consider the patho physiologic mechanisms responsible for our observations and review important details of the dorsal midbrain ocular motor circuitr y.
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Chun, Bo Young, i Kyung Min Kang. "Early Results of Slanted Recession of the Lateral Rectus Muscle for Intermittent Exotropia with Convergence Insufficiency". Journal of Ophthalmology 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/380467.
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The aim of this study was to evaluate the efficacy of slanted recession of the lateral rectus muscle for intermittent exotropia with convergence insufficiency. This prospective study included 31 patients who underwent slanted lateral rectus recession for intermittent exotropia with convergence insufficiency between June 2010 and June 2012. Following parameters were recorded and analyzed: patient sex, age, preoperative and postoperative near and distance ocular alignment, and changes in stereopsis. The mean age of the patients was 9.2 years. The preoperative mean deviation angle was 32.4 PD at distance and 43.4 PD at near. After 6 months, slanted lateral rectus recession reduced the deviation angles to 2 PD at distance and 3.4 PD at near. In addition, the mean difference between distance and near deviation angles was significantly reduced from 11 PD to 1.4 PD at 6 months postoperatively. Slanted lateral rectus recession for intermittent exotropia with convergence insufficiency in children successfully reduced the distance and near exodeviations and the near-distance difference without increasing the risk of long-term postoperative esotropia or diplopia.
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Moran, R. N., J. Wallace i T. Covassin. "Influence of Pre-Morbid Migraine History on Baseline Vestibular/Ocular Motor Screening and King-Devick Test Performance". Archives of Clinical Neuropsychology 34, nr 5 (lipiec 2019): 743. http://dx.doi.org/10.1093/arclin/acz026.13.
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Abstract Purpose To examine the effects of premorbid migraine history on baseline Vestibular/Ocular Motor Screening (VOMS) and King-Devick (KD) test performance in youth athletes. Methods This study implemented a cross-sectional design and was conducted at a series of youth sport venues in a designated research area. Youth athletes between the ages of 8 and 14 years with a diagnosed history of migraine headaches (n=28) and match controls (n=28) were administered a baseline VOMS and KD test. Between-group comparisons for provocation scores on the VOMS (smooth pursuit, saccades, convergence, vestibular-ocular reflex [VOR], and visual motion sensitivity [VMS]), Near-point of convergence [NPC] average distance (cm), and KD time (seconds) were conducted. Results Individuals diagnosed with migraine headaches reported greater VOMS scores compared to match controls on smooth pursuit (0.43±1.1 vs. 0.00±0.0; p=.02), convergence (0.46±1.2 vs. 0.04±0.1; p=.04), horizontal VOR (0.89±1.4 vs. 0.07±0.2; p<.001), vertical VOR (0.61±1.1 vs. 0.11±0.3; p=.04), and VMS (0.86±1.5 vs. 0.04±0.1; p=.01). Differences were also observed on the KD test with worse times in the diagnosed migraine group (54.33±11.8s) compared to match controls (47.17±8.9s; p=.02). No differences were reported on NPC distance between the migraine (2.22±3.1cm) and control group (0.83±1.2; p=.06). Conclusion Youth athletes with diagnosed migraine history reported higher baseline VOMS scores and worse KD time compared to match controls, further illustrating the influence of premorbid migraine headaches as a risk factor for elevated baseline concussion assessment. Special consideration may be warranted for post-concussion assessment in athletes with diagnosed migraine headaches.
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Chen, Yuanyuan, Yuwen Wang, Xinping Yu, Aiqin Xu, Jian Jiang i Hao Chen. "Effect of Illumination on Ocular Status Modifications Induced by Short-Term 3D TV Viewing". Neural Plasticity 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/1432037.
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Objectives.This study aimed to compare changes in ocular status after 3D TV viewing under three modes of illumination and thereby identify optimal illumination for 3D TV viewing.Methods.The following measures of ocular status were assessed: the accommodative response, accommodative microfluctuation, accommodative facility, relative accommodation, gradient accommodative convergence/accommodation (AC/A) ratio, phoria, and fusional vergence. The observers watched 3D television for 90 minutes through 3D shutter glasses under three illumination modes: A, complete darkness; B, back illumination (50 lx); and C, front illumination (130 lx). The ocular status of the observers was assessed both before and after the viewing.Results.After 3D TV viewing, the accommodative response and accommodative microfluctuation were significantly changed under illumination Modes A and B. The near positive fusional vergence decreased significantly after the 90-minute 3D viewing session under each illumination mode, and this effect was not significantly different among the three modes.Conclusions.Short-term 3D viewing modified the ocular status of adults. The least amount of such change occurred with front illumination, suggesting that this type of illumination is an appropriate mode for 3D shutter TV viewing.
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Kawata, K., R. Tierney, J. Phillips i J. Jeka. "Effect of Repetitive Sub-concussive Head Impacts on Ocular Near Point of Convergence". International Journal of Sports Medicine 37, nr 05 (9.02.2016): 405–10. http://dx.doi.org/10.1055/s-0035-1569290.
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Figtree, William V. C., Michael C. Schubert i Americo A. Migliaccio. "Horizontal Vestibulo-Ocular Reflex Gain Measures During Convergence Using a Monocular Video Technique". Otology & Neurotology 41, nr 1 (styczeń 2020): e118-e123. http://dx.doi.org/10.1097/mao.0000000000002414.
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Suleiman, Abdelbaset, Brian J. Lithgow, Neda Anssari, Mehrangiz Ashiri, Zahra Moussavi i Behzad Mansouri. "Correlation between Ocular and Vestibular Abnormalities and Convergence Insufficiency in Post-Concussion Syndrome". Neuro-Ophthalmology 44, nr 3 (9.10.2019): 157–67. http://dx.doi.org/10.1080/01658107.2019.1653325.
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Takagi, Mineo, Haruo Toda, Toyohisa Yoshizawa, Naoto Hara, Tomoo Ando, Haruki Abe i Takehiko Bando. "Ocular convergence-related neuronal responses in the lateral suprasylvian area of alert cats". Neuroscience Research 15, nr 3 (listopad 1992): 229–34. http://dx.doi.org/10.1016/0168-0102(92)90010-a.
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Rowe, Fiona J., David Wright, Darren Brand, Carole Jackson, Shirley Harrison, Tallat Maan, Claire Scott i in. "Profile of Gaze Dysfunction following Cerebrovascular Accident". ISRN Ophthalmology 2013 (10.10.2013): 1–8. http://dx.doi.org/10.1155/2013/264604.
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Aim. To evaluate the profile of ocular gaze abnormalities occurring following stroke. Methods. Prospective multicentre cohort trial. Standardised referral and investigation protocol including assessment of visual acuity, ocular alignment and motility, visual field, and visual perception. Results. 915 patients recruited: mean age 69.18 years (SD 14.19). 498 patients (54%) were diagnosed with ocular motility abnormalities. 207 patients had gaze abnormalities including impaired gaze holding (46), complete gaze palsy (23), horizontal gaze palsy (16), vertical gaze palsy (17), Parinaud’s syndrome (8), INO (20), one and half syndrome (3), saccadic palsy (28), and smooth pursuit palsy (46). These were isolated impairments in 50% of cases and in association with other ocular abnormalities in 50% including impaired convergence, nystagmus, and lid or pupil abnormalities. Areas of brain stroke were frequently the cerebellum, brainstem, and diencephalic areas. Strokes causing gaze dysfunction also involved cortical areas including occipital, parietal, and temporal lobes. Symptoms of diplopia and blurred vision were present in 35%. 37 patients were discharged, 29 referred, and 141 offered review appointments. 107 reviewed patients showed full recovery (4%), partial improvement (66%), and static gaze dysfunction (30%). Conclusions. Gaze dysfunction is common following stroke. Approximately one-third of patients complain of visual symptoms, two thirds show some improvement in ocular motility.
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Caetano, Joselany Afio, Maria Alzete Lima, Denise Araújo Silva i Jennara Cândido do Nascimento. "Repercussão da visão monocular após trauma ocular". Revista Brasileira de Enfermagem 64, nr 5 (październik 2011): 845–48. http://dx.doi.org/10.1590/s0034-71672011000500007.
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Pesquisa qualitativa convergente assistencial, que objetivou identificar percepções e significados referentes à perda visual de pacientes que apresentavam visão monocular devido ao trauma ocular. Participaram seis vítimas de trauma ocular com visão monocular, de um hospital referência em emergência. Os dados emergiram das falas das pessoas no grupo de convivência e de entrevistas semiestruturadas. Os resultados demonstraram expectativa de voltar a enxergar, dúvida quanto ao diagnóstico e ausência de acompanhamento, o qual despertou sentimento de angústia e situação conflituosa relacionada à perda da independência. O grupo de convivência foi considerado um elemento que contribuiu para um viver mais saudável, ao promover a troca de experiências e o compartilhar de saberes.
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Busettini, C., F. A. Miles i R. J. Krauzlis. "Short-latency disparity vergence responses and their dependence on a prior saccadic eye movement". Journal of Neurophysiology 75, nr 4 (1.04.1996): 1392–410. http://dx.doi.org/10.1152/jn.1996.75.4.1392.
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1. A dichoptic viewing arrangement was used to study the initial vergence eye movements elicited by brief horizontal disparity steps applied to large textured patterns in three rhesus monkeys. Disconjugate steps (range, 0.2-10.9 degrees) were applied to the patterns at selected times (range, 13-303 ms) after 10 degrees leftward saccades into the center of the pattern. The horizontal and vertical positions of both eyes were recorded with the electromagnetic search coil technique. 2. Without training or reinforcement, disparity steps of suitable amplitude consistently elicited vergence responses at short latencies. For example, with 1.8 degrees crossed-disparity steps applied 26 ms after the centering saccade, the mean latency of onset of convergence for each of the three monkeys was 52.2 +/- 3.8 (SD) ms, 52.3 +/- 5.2 ms, and 53.4 +/- 4.1 ms. 3. Experiments in which the disparity step was confined to only one eye indicated that each eye was not simply tracking the apparent motion that is saw. For example, when crossed-disparity steps were confined to the right eye (which saw leftward steps), the result was (binocular) convergence in which the left eye moved to the right even though that eye had seen only a stationary scene. This movement of the left eye cannot have resulted from independent monocular tracking and indicates that the vergences here derived from the binocular misalignment of the two retinal images. 4. The initial vergence responses to crossed-disparity steps had the following main features. 1) They were always in the correct (i.e., convergent) direction over the full range of stimuli tested, the initial vergence acceleration increasing progressively with increases in disparity until reaching a peak with steps of 1.4-2.4 degrees and declining thereafter to a nonzero asymptote as steps exceeded 5-7 degrees. 2) They showed transient postsaccadic enhancement whereby steps applied in the immediate wake of a saccadic eye movement resulted in much higher initial vergence accelerations than the same steps applied some time later. The response decline in the wake of a saccade was roughly exponential with time constants of 67 +/- 5 (SD) ms, 35 +/- 2 ms, and 54 +/- 4 ms for the three animals. 3) That the postsaccadic enhancement might have resulted in part from the visual stimulation associated with the prior saccade was suggested by the finding that enhancement could also be observed when the disparity steps were applied in the wake of (conjugate) saccadelike shifts of the textured pattern. However, this visual enhancement did not reach a peak unit 17-37 ms after the end of the "simulated" saccade, and the peak enhancement averaged only 45% of that after a "real" saccade. 4) Qualitatively similar transient enhancements in the wake of real and simulated saccades have also been reported for initial ocular following responses elicited by conjugate drifts of the visual scene. We replicated the enhancement effects on ocular following to allow a direct comparison with the enhancement effects on disparity vergence using the same animals and visual stimulus patterns and, despite some clear quantitative differences, we suggest that the enhancement effects share a similar etiology. 5. Initial vergence responses to uncrossed-disparity steps had the following main features. 1) They were in the correct (i.e., divergent) direction only for very small steps (< 1.5-2.5 degrees), and then only when postsaccadic delays were small; when the magnitude of the steps was increased beyond these levels, responses declined to zero and thereafter reversed direction, eventually reaching a nonzero (convergent) asymptote similar to that seen with large crossed-disparity steps; convergent responses were also seen with larger vertical disparity steps, suggesting that they represent default responses to any disparity exceeding a few degrees. 2) As the postsaccadic delay was increased, responses to small steps (1.8 degrees) declined to zero and thereafter re
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Kontos, Anthony P., Jamie McAllister Deitrick, Michael W. Collins i Anne Mucha. "Review of Vestibular and Oculomotor Screening and Concussion Rehabilitation". Journal of Athletic Training 52, nr 3 (1.03.2017): 256–61. http://dx.doi.org/10.4085/1062-6050-51.11.05.
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Vestibular and oculomotor impairment and symptoms may be associated with worse outcomes after sport-related concussion (SRC), including prolonged recovery. In this review, we evaluate current findings on vestibular and oculomotor impairments as well as treatment approaches after SRC, and we highlight areas in which investigation is needed. Clinical researchers have intimated that recovery from SRC may follow certain clinical profiles that affect the vestibular and oculomotor pathways. Identifying clinical profiles may help to inform better treatment and earlier intervention to reduce recovery time after SRC. As such, screening for and subsequent monitoring of vestibular and oculomotor impairment and symptoms are critical to assessing and informing subsequent referral, treatment, and return to play. However, until recently, no brief-screening vestibular and oculomotor tools were available to evaluate this injury. In response, researchers and clinicians partnered to develop the Vestibular/Ocular-Motor Screening, which assesses pursuits, saccades, vestibular ocular reflex, visual motion sensitivity, and convergence via symptom provocation and measurement of near-point convergence. Other specialized tools, such as the King-Devick test for saccadic eye movements and the Dizziness Handicap Inventory for dizziness, may provide additional information regarding specific impairments and symptoms. Tools such as the Vestibular/Ocular-Motor Screening provide information to guide specialized referrals for additional assessment and targeted rehabilitation. Vestibular rehabilitation and visual-oculomotor therapies involve an active, expose-recover approach to reduce impairment and symptoms. Initial results support the effectiveness of both vestibular and visual-oculomotor therapies, especially those that target specific impairments. However, the evidence supporting rehabilitation strategies for both vestibular and oculomotor impairment and symptoms is limited and involves small sample sizes, combined therapies, nonrandomized treatment groups, and lack of controls. Additional studies on the effectiveness of screening tools and rehabilitation strategies for both vestibular and oculomotor impairment and symptoms after SRC are warranted.
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Toda, Haruo, Hiruma Hasebe, Ritsuko Takada, Mineo Takagi i Takehiko Bando. "1523 Properties of ocular convergence-related neurons in the extrastriate cortex in the cat". Neuroscience Research 28 (styczeń 1997): S188. http://dx.doi.org/10.1016/s0168-0102(97)90511-3.
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King, W. Michael, Wu Zhou, R. David Tomlinson, Kathleen M. V. McConville, William K. Page, Gary D. Paige i James S. Maxwell. "Eye Position Signals in the Abducens and Oculomotor Nuclei of Monkeys During Ocular Convergence". Journal of Vestibular Research 4, nr 5 (1994): 401–8. http://dx.doi.org/10.3233/ves-1994-4509.
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Maruta, Jun, Hamish G. MacDougall, John I. Simpson, Theodore Raphan i Bernard Cohen. "Eye velocity asymmetry, ocular orientation, and convergence induced by angular rotation in the rabbit". Vision Research 46, nr 6-7 (marzec 2006): 961–69. http://dx.doi.org/10.1016/j.visres.2005.10.015.
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Hasebe, H., H. Oyamada, H. Toda, K. Ukai i T. Bando. "1642 Changes in ocular convergence during 3-d task using a hmd in humans". Neuroscience Research 25 (styczeń 1996): S184. http://dx.doi.org/10.1016/0168-0102(96)89076-6.
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ENGELMANN, RALF, JOHN M. CROOK i SIEGRID LÖWEL. "Optical imaging of orientation and ocular dominance maps in area 17 of cats with convergent strabismus". Visual Neuroscience 19, nr 1 (styczeń 2002): 39–49. http://dx.doi.org/10.1017/s0952523801191042.
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Strabismus (or squint) is both a well-established model for developmental plasticity of the brain and a frequent clinical symptom. While the layout and topographic relationship of functional domains in area 17 of divergently squinting cats has been analyzed extensively in recent years (e.g. Löwel et al., 1998), functional maps in convergently squinting animals have so far not been visualized with comparable detail. We have therefore investigated the functional organization of area 17 in adult cats with a surgically induced convergent squint angle. In these animals, visual acuity was determined by both behavioral tests and recordings of visual evoked potentials, and animals with comparable acuities in both eyes were selected for further experiments. The functional layout of area 17 was visualized using optical imaging of intrinsic signals. Monocular iso-orientation domains had a patchy appearance and their layout was different for left and right eye stimulation, so that segregated ocular dominance domains could be visualized. Iso-orientation domains exhibited a pinwheel-like organization, as previously described for normal and divergently squinting cats. Mean pinwheel density was the same in the experimental and control animals (3.4 pinwheel centers per mm2 cortical surface), but significantly (P < 0.00001) higher than that reported previously for normal and divergently squinting cats (2.7/mm2). A comparison of orientation with ocular dominance maps revealed that iso-orientation domains were continuous across the borders of ocular dominance domains and tended to intersect these borders at steep angles. However, in contrast to previous reports in normally raised cats, orientation pinwheel centers showed no consistent topographical relationship to the peaks of ocular dominance domains. Taken together, these observations indicate an overall similarity between the functional layout of orientation and ocular dominance maps in area 17 of convergently and divergently squinting cats. The higher pinwheel densities compared with previous reports suggest that animals from different gene pools might generally differ in this parameter and therefore also in the space constants of their cortical orientation maps.
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Livingston, Christine A., i Stacey Rickert Fedder. "Visual-Ocular Motor Activity in the Macaque Pregeniculate Complex". Journal of Neurophysiology 90, nr 1 (lipiec 2003): 226–44. http://dx.doi.org/10.1152/jn.00033.2003.
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The anatomical connections of the pregeniculate complex (PrGC) with components of the visual-ocular motor system suggested its contribution to ocular motor behavior. Subsequent studies reported saccade-related activity in the primate PrGC. To determine its contribution, we characterized pregeniculate units ( n = 128) in alert macaques during ocular motor tasks and visual stimulation. We found that 36/109 saccade-related units exhibited postsaccadic bursts or pauses in tonic discharge for saccades of any amplitude or direction. In contrast to previous results, 46/109 responses preceded or coincided with the saccade, while 47/109 responses were directionally tuned. Pregeniculate units were modulated not only in association with saccades (109/128) but also with smooth eye movements and visual motion (20/128) or eye position (23/128). Multiple ocular motor signals were recorded from 19% of the units, indicating signal convergence on individual neurons. Visual responses were demonstrated in 51% of PrGC units: visual field illumination modulated the resting discharge of 33 units; the responses of 37 saccade-related units and all 23 position-dependent units were modulated by visual stimulation. Early saccadic activity in the PrGC suggests that it contributes more to gaze than postsaccadic modulation of visual or ocular motor activity. The patterns of saccadic responses and the modulation of PrGC activity in association with a variety of visual-ocular motor behaviors suggest its potential role as a relay between the parietal cortex and elements of the brain stem ocular motor pathways, such as the superior colliculus and pretectal nucleus of the optic tract.
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Reddy, Sridhara, Gurunadh Satyanarayana Velamakanni i Shailesh Mogra. "Prevalence Study of Ocular Morbidity among Primary School Children in Delhi Area". Journal of Medical Academics 3, nr 2 (2020): 43–45. http://dx.doi.org/10.5005/jp-journals-10070-0048.
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ABSTRACT Aim To estimate the prevalence of ocular morbidity among primary school children in Delhi area. Materials and methods This was a descriptive cross-sectional study. The study was conducted among primary school children of age group 5–12 years in Delhi area. A total of 1,100 school-going children were evaluated. After questionnaire administration, visual acuity, examination of anterior and posterior segment structures of the eyes of the children were carried out. For the statistical analysis, children were divided into three groups: group I (5–7 years), group II (8–10 years), and group III ((<12 years) based on age. Results A total of 1,100 school children (625 boys and 475 girls) participated in the study. A total of 282 (25.6%) children had visual impairment and 315 (28.6%) children had ocular morbidities. The common ocular morbidities identified were refractive error 25.6%, color vision defective 0.9%, convergence defect 1.8%, and squint 0.2%. The older age group (8–10 years) had a higher prevalence of refractive error, especially myopia, compared to the younger age group (5–7 years) and group ((<12 years) (p < 0.001). Conclusion A high prevalence of ocular morbidity among school children of age group 8–10 years was observed. Refractive errors were the most common ocular disorders. This study emphasized that a simple school visual screening program is effective for the early detection of ocular problems. How to cite this article Reddy S, Velamakanni GS, Mogra S. Prevalence Study of Ocular Morbidity among Primary School Children in Delhi Area. J Med Acad 2020;3(2):43–45.
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Perlmutter, S. I., Y. Iwamoto, J. F. Baker i B. W. Peterson. "Interdependence of Spatial Properties and Projection Patterns of Medial Vestibulospinal Tract Neurons in the Cat". Journal of Neurophysiology 79, nr 1 (1.01.1998): 270–84. http://dx.doi.org/10.1152/jn.1998.79.1.270.
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Perlmutter, S. I., Y. Iwamoto, J. F. Baker, and B. W. Peterson. Interdependence of spatial properties and projection patterns of medial vestibulospinal tract neurons in the cat. J. Neurophysiol. 79: 270–284, 1998. Activity of vestibular nucleus neurons with axons in the ipsi- or contralateral medial vestibulospinal tract was studied in decerebrate cats during sinusoidal, whole-body rotations in many planes in three-dimensional space. Antidromic activation of axon collaterals distinguished between neurons projecting only to neck segments from those with collaterals to C6 and/or oculomotor nucleus. Secondary neurons were identified by monosynaptic activation after labyrinth stimulation. A three-dimensional maximum activation direction vector (MAD) summarized the spatial properties of 151 of 169 neurons. The majority of secondary neurons (71%) terminated above the C6 segment. Of these, 43% had ascending collaterals to the oculomotor nucleus (VOC neurons), and 57% did not (VC neurons). The majority of VOC and VC neurons projected contralaterally and ipsilaterally, respectively. Most C6-projecting neurons could not be activated from oculomotor nucleus (V-C6 neurons) and projected primarily ipsilaterally. All VO-C6 neurons projected contralaterally. The distributions of MADs for secondary neurons with different projection patterns were different. Most VOC (84%) and contralaterally projecting VC (91%) neurons had MADs close to the activation vector of a semicircular canal pair, compared with 54% of ipsilaterally projecting VC (i-VC) and 39% of V-C6 neurons. Many i-VC (44%) and V-C6 (48%) neurons had responses suggesting convergent input from horizontal and vertical canal pairs. Horizontal and vertical gains were comparable for some, making it difficult to assign a primary canal input. MADs consistent with vertical-vertical canal pair convergence were less common. Type II yaw or type II roll responses were seen for 22% of the i-VC neurons, 68% of the V-C6 neurons, and no VOC cells. VO-C6 neurons had spatial properties between those of VOC and V-C6 neurons. These results suggest that secondary VOC neurons convey semicircular canal pair signals to both ocular and neck motor centers, perhaps linking eye and head movements. Secondary VC and V-C6 neurons carry more processed signals, possibly to drive neck and forelimb reflexes more selectively. Two groups of secondary i-VC neurons exhibited vertical-horizontal canal convergence similar to that present on neck muscles. The vertical-vertical canal convergence present on many neck muscles, however, was not present on medial vestibulospinal neurons. Spatial transformations achieved by the vestibulocollic reflex may occur in part on secondary neurons but further combination of canal signals must take place to generate compensatory muscle activity.
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Zhang, Y., L. E. Mays i P. D. Gamlin. "Characteristics of near response cells projecting to the oculomotor nucleus". Journal of Neurophysiology 67, nr 4 (1.04.1992): 944–60. http://dx.doi.org/10.1152/jn.1992.67.4.944.
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1. Previous work has shown neurons just dorsal and lateral to the oculomotor nucleus that increase their firing rate with increases in the angle of ocular convergence. It has been suggested that the output of these midbrain near response cells might provide the vergence command needed by the medial rectus motoneurons. However, lens accommodation ordinarily accompanies convergence, and a subsequent study showed that only about one-half of these midbrain near response cells carried a signal related exclusively to vergence. One hypothesis suggested by this finding is that this subgroup of neurons might have a unique role in providing a "pure" vergence signal to the medial rectus motoneurons. 2. In the present study extracellular recordings were made from midbrain near response cells in monkeys while eye position and lens accommodation were measured. The monkeys viewed targets through an optical system that allowed the accommodative and ocular vergence demands to be manipulated independently. This approach was used to produce a partial dissociation of accommodative and vergence responses, so that an accommodative and vergence coefficient could be determined for each cell, by the use of the following equation FR = R0 + kda x AR + kdv x CR where FR is the firing rate of the near response cell, R0 is the predicted firing rate for a distant target, kda is the (dissociated) accommodation coefficient, AR is the accommodative response, kdv is the (dissociated) vergence coefficient, and CR is the convergence response. 3. The vergence and accommodation coefficients were determined for a large number of midbrain near response cells, including a subset that could be antidromically activated from the medial rectus subdivisions of the oculomotor nucleus. Some near response neurons were found with signals related exclusively to convergence (i.e., kdv greater than 0 and kda = 0), whereas several others had signals related exclusively to lens accommodation (i.e., kda greater than 0 and kdv = 0). The majority of the near response cells had signals related to both responses (i.e., kda not equal to 0 and kdv not equal to 0). Furthermore, the vergence and accommodation coefficients of near response cells appeared to be continuously distributed. Some cells had negative accommodation or vergence coefficients. 4. The 17 near response cells that could be antidromically activated from the oculomotor nucleus presumably provide vergence signals to the medial rectus motoneurons. Although all had positive vergence coefficients, only four of these cells carried signals that were related exclusively to vergence.(ABSTRACT TRUNCATED AT 400 WORDS)
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Marasini, S., R. Sharma, P. R. Sthapit, D. Sharma, U. Koju, G. Thapa i B. P. Nepal. "Refractive Errors and Visual Anomalies in Schoolchildren in the Kavrepalanchowk District". Kathmandu University Medical Journal 8, nr 4 (4.06.2012): 362–66. http://dx.doi.org/10.3126/kumj.v8i4.6231.
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Background Schoolchildren form an important target group for a nation, as any ocular morbidity in this age group has huge physical, psychological and socio-economical implications. Childhood eye disorders can contribute to the burden of blindness in any society. This study aims to highlight the prevalence of ocular morbidity in governmental schools in a sub-urbanised area of Nepal, in relation to ethnic variation. Methods A descriptive study, and the study population used were schoolchildren who were examined in their schools and afterwards referred to the hospital if required. Presenting and best corrected visual acuity, refraction, binocularity assessment, anterior and posterior segment evaluation was carried out. Data was analysed statistically using SPSS software, version 14. Results We examined 1,802 school children. The mean age was 10.78±3.61 years. Ocular abnormality was detected in 11.7%. Low vision and blindness was rare (0.11% and 0.05%). Ocular morbidities were more common in Newar communities (3.71%) followed by Brahamans (3.38%). Lid abnormalities were the most common (3.55%), and morbidities in each ethnicity were followed by refractive errors (3%), conjunctival abnormalities (1.10%), strabismus (0.88%) and amblyopia (0.33%). Refractive errors were most common among Newar communities (1.16%) at almost twice as many Brahamans (0.61%) followed by Mongolians (0.49%). Convergence insufficiency was detected in 2.49% (p<0.01). Conclusions Ocular morbidities are common in children in Kavhrepalanchowk District with lid abnormalities being the most common issue, probably due to a lack of hygienic practice. Ethnic variation of ocular morbidities is an important observation mostly for refractive error and strabismus.http://dx.doi.org/10.3126/kumj.v8i4.6231 Kathmandu Univ Med J 2010;8(4):362-6
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Yonas, A., C. E. Granrud i J. Grittner. "Size-distance perception based on ocular convergence angle in 3- to 5-year-old children". Journal of Vision 6, nr 6 (24.03.2010): 733. http://dx.doi.org/10.1167/6.6.733.
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Man, B. L., i Y. P. Fu. "Acute esotropia, convergence-retraction nystagmus and contraversive ocular tilt reaction from a paramedian thalamomesencephalic infarct". Case Reports 2014, jun11 2 (11.06.2014): bcr2014205168. http://dx.doi.org/10.1136/bcr-2014-205168.
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