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BACKGROUND: The ocular vestibular evoked myogenic potential is otolith-dependent and has been suggested to be a manifestation of the linear vestibulo-ocular reflex (L-VOR). A characteristic feature of the translational LVOR (t-LVO...
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BACKGROUND: The ocular vestibular evoked myogenic potential is otolith-dependent and has been suggested to be a manifestation of the linear vestibulo-ocular reflex (L-VOR). A characteristic feature of the translational LVOR (t-LVOR) is its dependence on the distance of a target. OBJECTIVE: To assess if viewing distance affects amplitude and latency properties of the ocular vestibular evoked myogenic potential (oVEMPs). METHODS: Bone- and air-conducted (BC and AC) stimuli were used to evoke oVEMPs in 10 healthy subjects. BC stimuli consisted of impulsive accelerations applied at the mastoids, AFz, Oz and Iz. AC stimuli consisted of 500?Hz tones delivered unilaterally to each ear. Target distances of 40?cm (near), 190?cm (intermediate) and 340?cm (far) were used for all stimuli. RESULTS: The largest amplitude oVEMP was obtained from Iz and the latency for AFz was shorter than for BC stimulation at other sites. We found no significant effect of target distance on oVEMP amplitudes for any of the stimuli used. There was a small but significant effect on latency with the nearest target having a longer latency (overall 12.4?ms vs 12.0?ms for the 2 more distant sites). CONCLUSIONS: Previously reported differences between latencies and stimulus sites for midline BC stimulation were confirmed. Target distance had no significant effect on oVEMP amplitude, which suggests it is not modified like other components of the t-LVOR.
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In general, multi-view autostereoscopic displays can only provide autostereoscopic images with little crosstalk at the optimum viewing distance (OVD) in the depth direction, limiting the mobility of viewers. Therefore, this paper ...
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In general, multi-view autostereoscopic displays can only provide autostereoscopic images with little crosstalk at the optimum viewing distance (OVD) in the depth direction, limiting the mobility of viewers. Therefore, this paper proposes a method of increasing viewer mobility in the depth direction by varying the distance separating the parallax barrier and the display. Computer simulations and experiments were conducted to verify changes in the OVD resulting from the application of the proposed method. The results showed that the proposed method is effective at changing the OVD with respect to changes in the viewing distance. Therefore this method minimizes changes in the 3D image quality due to the viewer's depth location. (C) 2016 Elsevier B.V. All rights reserved.
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We have shown in a previous paper that preferred viewing distance (PVD)-a viewer's favored distance from which to watch TV in the home viewing environment-is shorter when watching a high spatial resolution 4k TV than on a high-def...
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We have shown in a previous paper that preferred viewing distance (PVD)-a viewer's favored distance from which to watch TV in the home viewing environment-is shorter when watching a high spatial resolution 4k TV than on a high-definition TV (HDTV). PVD depends on (1) the spatial resolution of the viewer's object of interest in the relevant scene, (2) whether viewers have sufficient time to optimize their PVD, as with still images, and (3) whether they are appropriately encouraged to pay attention to the object at hand on the screen, by, for example, narrative instructions. In this paper, we demonstrate that an analogous result is obtained in a comparison between high spatial resolution 8k TV and HDTV: The PVD of viewers for 8kTV is shorter than that for HDTV. This result suggests new possibilities for high spatial resolution TV, such as novel applications and TV programs that are especially developed for 8k TV systems.
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In this paper we explore and validate the merits of using absolute and relative viewing distances from the screen as complementary input modalities for interactive systems. We motivate the use of viewing distance as a complementar...
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In this paper we explore and validate the merits of using absolute and relative viewing distances from the screen as complementary input modalities for interactive systems. We motivate the use of viewing distance as a complementary modality by first mapping out its design space and then proposing several new applications that could benefit from it. We demonstrate that both absolute and relative viewing distance can be reliably estimated under controlled circumstances for both desktop and mobile devices using low-cost cameras and readily available computer vision algorithms. In our evaluations we find that viewing distance is a promising complementary input modality that can be reliably estimated using computer vision in environments with constant lighting. For environments with heterogeneous lighting conditions several challenges still exist when designing practical systems. To aid practitioners and researchers we conclude by highlighting several design implications for future systems.
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Postural control relies to visual-motion processing (afferent or efferent) and this is thought to be deficient in dyslexics. There is a controversy between clinic and fundamental studies as to the presence of posture abnormalities...
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Postural control relies to visual-motion processing (afferent or efferent) and this is thought to be deficient in dyslexics. There is a controversy between clinic and fundamental studies as to the presence of posture abnormalities in dyslexics. To explore further this issue, this study examines posture stability in quite stance in 13 dyslexics (mean age: 13.5 years) and in 13 non-dyslexics (mean age: 13 years). Experiment 1 shows that, similarly to adults and elderly, all children (dyslexics and non-dyslexics), present better stability at near distance (i.e. smaller surface area of the COP, smaller lateral and antero-posterior oscillations). This could be due to reduced angular size of retinal motion signals at far, but also to convergence relaxation. Importantly, the surface area of the COP, lateral and antero-posterior oscillations are significantly higher in dyslexics. Experiment 2 examines posture stability while subjects make active vergence movements between a far and a near target. For many dyslexics, moving the eyes back and forth in depth rather improved postural stability. The only significant difference was that the lateral oscillations were still higher in dyslexics. Experiment 3 uses eye movement recordings (video-oculography) and demonstrates that dyslexics have problems with maintaining stable the angle of vergence for a prolonged period. We conclude that mild postural instability may exist in dyslexics but it could be improved by oculomotor and attention processes.
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Postural control relies to visual-motion processing (afferent or efferent) and this is thought to be deficient in dyslexics. There is a controversy between clinic and fundamental studies as to the presence of posture abnormalities...
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Postural control relies to visual-motion processing (afferent or efferent) and this is thought to be deficient in dyslexics. There is a controversy between clinic and fundamental studies as to the presence of posture abnormalities in dyslexics. To explore further this issue, this study examines posture stability in quite stance in 13 dyslexics (mean age: 13.5 years) and in 13 non-dyslexics (mean age: 13 years). Experiment 1 shows that, similarly to adults and elderly, all children (dyslexics and non-dyslexics), present better stability at near distance (i.e. smaller surface area of the COP, smaller lateral and antero-posterior oscillations). This could be due to reduced angular size of retinal motion signals at far, but also to convergence relaxation. Importantly, the surface area of the COP, lateral and antero-posterior oscillations are significantly higher in dyslexics.Experiment 2 examines posture stability while subjects make active vergence movements between a far and a near target. For many dyslexics, moving the eyes back and forth in depth rather improved postural stability. The only significant difference was that the lateral oscillations were still higher in dyslexics. Experiment 3 uses eye movement recordings (video-oculography) and demonstrates that dyslexics have problems with maintaining stable the angle of vergence for a prolonged period. We conclude that mild postural instability may exist in dyslexics but it could be improved by oculomotor and attention processes.
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This study explored the viewing distance and screen angle for electronic paper (E-Paper) displays under various light sources, ambient illuminations, and character sizes. Data analysis showed that the mean viewing distance and scr...
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This study explored the viewing distance and screen angle for electronic paper (E-Paper) displays under various light sources, ambient illuminations, and character sizes. Data analysis showed that the mean viewing distance and screen angle were 49.5 mm and 123.7°. The mean viewing distances for Kolin Chlorestic Liquid Crystal display was 500 mm, significantly longer than Sony electronic ink display, 491 mm. Screen angle for Kolin was 127.4°, significantly greater than that of Sony, 120.0°. Various light sources revealed no significant effect on viewing distances; nevertheless, they showed significant effect on screen angles. The screen angle for sunlight lamp (D65) was similar to that of fluorescent lamp (TL84), but greater than that of tungsten lamp (F). Ambient illumination and E-paper type had significant effects on viewing distance and screen angle. The higher the ambient illumination was, the longer the viewing distance and the lesser the screen angle. Character size had significant effect on viewing distances: the larger the character size, the longer the viewing distance. The results of this study indicated that the viewing distance for E-Paper was similar to that of visual display terminal (VDT) at around 500 mm, but greater than normal paper at about 360 mm. The mean screen angle was around 123.7°, which in terms of viewing angle is 29.5° below horizontal eye level. This result is similar to the general suggested viewing angle between 20° and 50° below the horizontal line of sight.
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Evidence about the effect of smartphone use on accommodation is limited and inconclusive. Several studies have investigated either symptoms or near triad measures following smartphone use. These suggest that, certainly for the sho...
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Evidence about the effect of smartphone use on accommodation is limited and inconclusive. Several studies have investigated either symptoms or near triad measures following smartphone use. These suggest that, certainly for the short term, smartphones have a negative impact on the near triad and produce symptoms. In addition, there is a body of recent work reporting cases of acute acquired concomitant esotropia (AACE) that may be caused by the accommodation-vergence demand of excessive smartphone use. A pilot study was undertaken to investigate accommodative measures before and after 30 minutes of smartphone use. Participants aged 16-40 years were invited to participate. Accommodative facility (AF), near point of accommodation (NPA), and near point of convergence (NPC) before and after 30 minutes of habitual smartphone use were assessed. NPA and AF were assessed with both eyes open (BEO), right eye (RE) and left eye (LE). Accommodative facility was assessed using +/- 2DS flipper lenses and measured in cycles per minute (cpm). NPA and NPC were assessed using the RAF rule and measured in centimeters. Data were analyzed in StatsDirect using non-parametric statistical tests. Eighteen participants were recruited, with a mean age of 24 years (SD: 7.6yrs). AF improved by 3cpm (p= .015) for BEO, 2.25cpm for RE (p = .004) and 1.5 cpm for the LE (p =. 278) after smartphone use. NPA with BEO became worse by 2 cm (p =.0474), with the RE worse by 0.5cms (p = .0474) and the LE, worse by 0.125 cms (p = .047). Convergence worsened by 0.75 cms (p = .018). Although these appeared to represent a change in measures following smartphone use, post-hoc analysis with Bonferroni correction demonstrated that these were not statistically significant at the 0.07 significance level. This pilot study found that there was no difference in accommodative and convergence measures before and after 30 minutes of smartphone use. These results suggest evidence contrary to the existing literature. There are several limitations to this pilot study and previous work, which are discussed. Suggestions on future work to explore the effect of smartphone use on the near triad to address limitations and further knowledge, in this area, are provided.
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Analysis of the nearest reported distance in accounts of seemingly unknown, large, marine animals (sea monsters) by boat- or water-based eyewitnesses, revealed that, contrary to expectation, the majority of sightings were at close...
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Analysis of the nearest reported distance in accounts of seemingly unknown, large, marine animals (sea monsters) by boat- or water-based eyewitnesses, revealed that, contrary to expectation, the majority of sightings were at close distance (< 200 m). This suggests that misidentification of inanimate objects or known animal species due to great distance was unlikely. Assuming a uniform distribution of objects around the boat, the reported sightings were far closer than expected, implying a bias in the sighting or reporting process. The distribution of reported distances from boat- or water-based eyewitnesses was almost identical to that of shore-based witnesses. Unidentified large marine animals were more likely to be reported to be closer if the report was anonymous or secondhand. The gap of time between recollection/reporting and the actual sighting did not influence reported distance. There was no relation between reported distance and reported length. There was some equivocal evidence that the absence of a stated distance in a report might be an indicator of a hoax.
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