331 results on '"Visual sensitivity"'
Search Results
2. Characteristics of visual sensitivity in familial cortical myoclonic tremor and epilepsy
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Yujia Cao, Wenjuan Zhang, Xiaoli Wang, Jiang Zhu, Yonghong Liu, Jin-Xiang Wang, and Bi Wang
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medicine.medical_specialty ,genetic structures ,medicine.diagnostic_test ,business.industry ,Electroencephalography ,Epilepsies, Myoclonic ,Video sequence ,General Medicine ,Audiology ,medicine.disease ,Visual sensitivity ,eye diseases ,Pedigree ,Epilepsy ,Neurology ,Neuroimaging ,Tremor ,medicine ,Reflex ,Humans ,In patient ,Photosensitivity Disorders ,Neurology (clinical) ,business - Abstract
The aim of the study was to describe the electroclinical features of visual sensitivity in patients with familial cortical myoclonic tremor and epilepsy. We searched the EEG database using the terms "familial cortical myoclonic tremor and epilepsy" and "visual sensitivity" over a seven-year period from March 2013 to April 2020 in the Xijing hospital, Xi'an, China. The inclusion criteria were demonstrable electroclinical visual sensitivity in the form of eye-opening sensitivity, eye-closure sensitivity, eyes-closed sensitivity and photosensitivity. Clinical, EEG and imaging records of patients were screened, and subsequently, detailed analysis of their data was undertaken. We enrolled six patients with visual sensitivity, five of whom suffered with rare generalized tonic-clonic seizures. Neuroimaging was negative in all cases. All patients demonstrated photosensitivity; eye-opening sensitivity associated with cortical myoclonic in one patient, eyes-closed sensitivity associated with cortical myoclonic tremor status in three patients, and eye-closure sensitivity in two patients. At the last follow-up visit, cortical myoclonic tremor and epilepsy in all patients was well controlled with first-line treatment. Visual sensitivity is therefore likely to be an important reflex trait in some patients with familial cortical myoclonic tremor and epilepsy, and should be routinely evaluated in order to better define the electroclinical features in FCMTE syndrome. [Published with video sequences]. more...
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- 2021
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3. Increased Visual Sensitivity and Occipital Activity in Patients With Hemianopia Following Vision Rehabilitation
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Kristin Jünemann, Arash Sahraie, Sara Ajina, and Holly Bridge
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medicine.medical_specialty ,genetic structures ,medicine.medical_treatment ,Development/Plasticity/Repair ,Vision Disorders ,Optic chiasm ,Audiology ,Affect (psychology) ,rehabilitation ,Blindness, Cortical ,Quality of life ,perimetry ,Medicine ,Humans ,Vision rehabilitation ,cortical blindness ,Research Articles ,Visual Cortex ,hemianopia ,Rehabilitation ,business.industry ,General Neuroscience ,Visual sensitivity ,eye diseases ,Visual field ,V5/hMT ,medicine.anatomical_structure ,functional MRI ,Visual Fields ,business ,Occipital lobe - Abstract
Hemianopia, loss of vision in half of the visual field, results from damage to the visual pathway posterior to the optic chiasm. Despite negative effects on quality of life, few rehabilitation options are currently available. Recently, several long-term training programs have been developed that show visual improvement within the blind field, although little is known of the underlying neural changes. Here, we have investigated functional and structural changes in the brain associated with visual rehabilitation. Seven human participants with occipital lobe damage enrolled in a visual training program to distinguish which of two intervals contained a drifting Gabor patch presented within the blind field. Participants performed ∼25 min of training each day for 3–6 months and undertook psychophysical tests and a magnetic resonance imaging scan before and after training. A control group undertook psychophysical tests before and after an equivalent period without training. Participants who were not at ceiling on baseline tests showed on average 9.6% improvement in Gabor detection, 8.3% in detection of moving dots, and 9.9% improvement in direction discrimination after training. Importantly, psychophysical improvement only correlated with improvement in Humphrey perimetry in the trained region of the visual field. Whole-brain analysis showed an increased neural response to moving stimuli in the blind visual field in motion area V5/hMT. Using a region-of-interest approach, training had a significant effect on the blood oxygenation level-dependent signal compared with baseline. Moreover, baseline V5/hMT activity was correlated to the amount of improvement in visual sensitivity using psychophysical and perimetry tests. This study, identifying a critical role for V5/hMT in boosting visual function, may allow us to determine which patients may benefit most from training and design adjunct interventions to increase training effects. SIGNIFICANCE STATEMENT Homonymous visual field loss is a common consequence of brain injury and is estimated to affect more than 230,000 people in the United Kingdom. Despite its high prevalence and well-described impact on quality of life, treatments to improve visual sensitivity remain experimental, and deficits are considered permanent after 6 months. Our study shows that behavioral changes following vision rehabilitation are associated with enhanced visually-evoked occipital activity to stimuli in the blind visual field. Unlike previous behavioral studies, we observe clinical changes that are specific to the trained region of vision. This lends significant weight to such training paradigms and offers a mechanism by which visual function can be improved despite damage to the primary visual pathway. more...
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- 2021
4. Comparison of central visual sensitivity between monocular and binocular testing in advanced glaucoma patients using imo perimetry
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Tomoyuki Kumagai, Yuji Yoshikawa, Hirokazu Ishii, Junji Kanno, Kei Shinoda, Itaru Kimura, Sho Ishikawa, Takuhei Shoji, Izumi Mine, and Akane Saito
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Male ,Retinal Ganglion Cells ,Visual acuity ,genetic structures ,Visual Acuity ,Glaucoma ,0302 clinical medicine ,Nerve Fibers ,Medicine ,Aged, 80 and over ,Vision, Binocular ,Clinical Science ,Middle Aged ,Visual sensitivity ,Sensory Systems ,Visual field ,Female ,medicine.symptom ,Glaucoma, Open-Angle ,medicine.medical_specialty ,field of vision ,Vision Disorders ,Sensitivity and Specificity ,Perimeter ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Predictive Value of Tests ,Vision, Monocular ,Ophthalmology ,Humans ,In patient ,False Positive Reactions ,Intraocular Pressure ,Aged ,Monocular ,business.industry ,medicine.disease ,eye diseases ,Absolute deviation ,glaucoma ,Cross-Sectional Studies ,physiology ,030221 ophthalmology & optometry ,Quality of Life ,Visual Field Tests ,sense organs ,Visual Fields ,business ,030217 neurology & neurosurgery - Abstract
Background/AimThis study aimed to compare central visual sensitivity under monocular and binocular conditions in patients with glaucoma using the new imo static perimetry.MethodsFifty-one consecutive eyes of 51 patients with open-angle glaucoma who were affected with at least one significant point in the central 10° were examined in this cross-sectional study. Monocular and binocular random single-eye tests were performed using the imo perimeter and the Humphrey field analyser (HFA) 24-2 and 10-2 tests. The eyes were assigned to ‘better’ and ‘worse’ categories based on the visual acuity and central visual thresholding. Central visual sensitivity results obtained by monocular, binocular random single-eye tests and binocular simultaneous both eye test were compared.ResultsThe average mean deviation with the HFA 24-2 was −5.5 (–1.5, –14.6) dB (median, (IQR)) in the better eyes and −18.0 (–12.9, –23.8) dB in the worse eyes. The mean sensitivity in the central 4 points of the visual field (VF) of the worse eyes was lower when measured under the binocular eye condition than under the monocular condition. Conversely, this value of the better eyes was greater when measured under the binocular eye condition than under the monocular condition.ConclusionsThe central sensitivity of the better eyes was better and that of the worse eyes poorer with binocular testing than with monocular testing in patients with glaucoma. Although monocular VF testing is still the most straightforward means to monocularly monitor glaucoma at clinical settings, binocular testing, such as provided with imo perimetry, may be a useful clinical tool to predict the effect of VF impairments on a patient’s quality of visual life. more...
- Published
- 2020
5. UV sensitive vision in cardinals and tanagers is ubiquitous
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Pablo D Lavinia, Belén Casalía, Pablo L. Tubaro, Ana S. Barreira, and Elisabet Vilacoba
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Physics ,Optics ,genetic structures ,business.industry ,Colour Vision ,Animal Science and Zoology ,Photopigment ,sense organs ,business ,Visual sensitivity ,Cone (formal languages) ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
Short wavelength visual sensitivity in birds is determined mostly by the type of photopigment present in the short-wavelength sensitive cone 1 (SWS1) which varies between clades and takes two main forms: the violet sensitive type (VS) and ultraviolet sensitive type (UVS). The common ancestor of passerines is thought to have been UVS, but there were at least 8 transitions between both types of visual sensitivity, even within species of the same family (Maluridae). The type of visual system a species has is a key parameter of avian visual models employed to describe chromatic visual perception and assess if colour differences are discernible by birds. Cardinalidae and Thraupidae together include more than 400 very diverse species that were model organisms in many bird colouration studies. However, visual sensitivity has been characterised for only one species of each of these families so far. Here, we obtained partial genetic sequences of the SWS1 opsin gene that determines the spectral sensitivity of the photopigment for a phylogenetically broad species sample of these families. All cardinals and tanagers studied here have SWS1 sequences corresponding with UVS sensitivity, suggesting that this character is conserved in these bird families despite their highly diverse range of plumage colours and habitat types. more...
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- 2020
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6. Obstacle avoidance in bumblebees is robust to changes in light intensity
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Emily Baird
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030110 physiology ,0301 basic medicine ,Forage (honey bee) ,Light ,Vision ,Computer science ,Short Communication ,Dusk ,Experimental and Cognitive Psychology ,Motion ,03 medical and health sciences ,0302 clinical medicine ,Obstacle avoidance ,Animals ,Computer vision ,Bumblebee ,Ecology, Evolution, Behavior and Systematics ,Light intensity ,business.industry ,Bees ,Visual sensitivity ,Visual field ,Flight ,Flight, Animal ,Obstacle ,Artificial intelligence ,Visual Fields ,Fast motion ,business ,Insect ,030217 neurology & neurosurgery - Abstract
Flying safely and avoiding obstacles in low light is crucial for the bumblebees that forage around dawn and dusk. Previous work has shown that bumblebees overcome the limitations of their visual system—typically adapted for bright sunlight—by increasing the time over which they sample photons. While this improves visual sensitivity, it decreases their capacity to resolve fast motion. This study investigates what effect this has on obstacle avoidance in flight, a task that requires the bees to reliably detect obstacles in the frontal visual field and to make a timely diversion to their flight path. In both bright and dim light, bumblebees avoided the 5 cm diameter obstacle at a consistent distance (22 cm) although in dim light they approached it more slowly from a distance of at least at least 80 cm. This suggests that bumblebees have an effective strategy for avoiding obstacles in all light conditions under which they are naturally active, and it is hypothesised that this is based on a time-to-contact prediction. Electronic supplementary material The online version of this article (10.1007/s10071-020-01421-z) contains supplementary material, which is available to authorized users. more...
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- 2020
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7. Visual space curves before eye movements
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Ifedayo-EmmanuEL Adeyefa-Olasupo
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Visual processing ,business.industry ,Computer science ,Visual space ,Eye movement ,Computer vision ,Artificial intelligence ,Percept ,business ,Visual sensitivity ,Gaze - Abstract
In most experiments within the field of cognitive and systems neuroscience, fixation is often required prior to the onset of an experimental trial. However, the term “fixation” is rather misleading since our eyes are constantly moving. One type of transient miniature movement ubiquitously observed during fixation is commonly referred to as fixational eye movements or microsaccades. Perimicrosaccadic compression of visual space — the ability of retinotopic cells to transiently exhibit predictive spatiotemporal retinotopic compressive shifts toward the target of an impending microsaccade — is known to dramatically alter visual perception. However, whether perimicrosaccadic compressive shifts can become spatially asymmetric, that is, continuously directed toward a specific foveal region over another (e.g., an upper over a lower region in the fovea) and for what purpose, remains poorly understood. Assuming that these transient shifts are indeed asymmetric under certain conditions, the perceptual and oculomotor consequences such asymmetricity might accompany across visual space is poorly understood. Equally unaccounted for is a mechanistic account of the neural computation and architecture that could support these transient asymmetric shifts while the visual system actively maintains retinotopic organization. Here, we systematically measured visual sensitivity in human subjects to faint probes presented during fixation and around the time of saccadic eye movement at geometrically symmetric retinotopic locations in the foveal, parafoveal, and peripheral regions of visual space. Remarkably, we observed transient local asymmetric visual sensitivity differences between these symmetric retinotopic locations where none should be observed. Equally surprising, we observed the trajectories of saccadic eye movements, which are expected to travel along a linear path, routinely deviate along a curved path toward orthogonal eccentric locations. To provide a mechanistic account of the neural computation and architecture that may explain our results, we proposed a novel neurobiologically inspired phenomenological force field model in which underlying attentional and oculomotor signals are modulated by transient eccentric error signals that manifest as temporally overlapping predictive forces and impinge on the retinotopic visual cortex. These forces, which transiently bias putative population sensitivity toward an orthogonal retinotopic foveal region and, around the time of a saccadic eye movement, along an axis orthogonal to the saccade direction toward a mislocalized peripheral region, succinctly capture the essence of our empirical observations. more...
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- 2021
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8. Cortical Hyper‐Excitability in Migraine in Response to Chromatic Patterns
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Pulkit Grover, Sarah M. Haigh, Alireza Chamanzar, and Marlene Behrmann
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Adult ,Male ,medicine.medical_specialty ,genetic structures ,Aura ,Migraine Disorders ,Audiology ,Young Adult ,03 medical and health sciences ,Neural activity ,0302 clinical medicine ,Humans ,Medicine ,030212 general & internal medicine ,Chromatic scale ,Chromaticity ,Hue ,Cerebral Cortex ,business.industry ,Electroencephalography ,Middle Aged ,medicine.disease ,Visual sensitivity ,Neurology ,Migraine ,Cortical Excitability ,Evoked Potentials, Visual ,Female ,Neurology (clinical) ,business ,Color Perception ,Photic Stimulation ,030217 neurology & neurosurgery - Abstract
Objective Individuals with migraine exhibit heightened sensitivity to visual input that continues beyond their migraine episodes. However, the contribution of color to visual sensitivity, and how it relates to neural activity, has largely been unexplored in these individuals. Background Previously, it has been shown that, in non-migraine individuals, patterns with greater chromaticity separation evoked greater cortical activity, regardless of hue, even when colors were isoluminant. Therefore, to investigate whether individuals with migraine experienced increased visual sensitivity, we compared the behavioral and neural responses to chromatic patterns of increasing separation in migraine and non-migraine individuals. Methods Seventeen individuals with migraine (12 with aura) and 18 headache-free controls viewed pairs of colored horizontal grating patterns that varied in chromaticity separation. Color pairs were either blue-green, red-green, or red-blue. Participants rated the discomfort of the gratings and electroencephalogram was recorded simultaneously. Results Both groups showed increased discomfort ratings and larger N1/N2 event-related potentials (ERPs) with greater chromaticity separation, which is consistent with increased cortical excitability. However, individuals with migraine rated gratings as being disproportionately uncomfortable and exhibited greater effects of chromaticity separation in ERP amplitude across occipital and parietal electrodes. Ratings of discomfort and ERPs were smaller in response to the blue-green color pairs than the red-green and red-blue gratings, but this was to an equivalent degree across the 2 groups. Conclusions Together, these findings indicate that greater chromaticity separation increases neural excitation, and that this effect is heightened in migraine, consistent with the theory that hyper-excitability of the visual system is a key signature of migraine. more...
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- 2019
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9. Wavelength‐specific thresholds of artificially reared Japanese eelAnguilla japonicalarvae determined from negative‐phototactic behaviours
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Keishi Matsuda, Masaaki Kamoshida, and Yoshitsugu Masuda
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0106 biological sciences ,Light ,Aquaculture ,Aquatic Science ,010603 evolutionary biology ,01 natural sciences ,Japonica ,Optics ,Japan ,Anguillidae ,Phototaxis ,Animals ,Japanese eel ,Ecology, Evolution, Behavior and Systematics ,Larva ,biology ,business.industry ,010604 marine biology & hydrobiology ,Anguilla ,biology.organism_classification ,Visual sensitivity ,Wavelength ,Spectral sensitivity ,business - Abstract
We report wavelength-specific thresholds of leptocephali of Japanese eels Anguilla japonica determined from their negative-phototactic behaviour. Leptocephali are most sensitive to wavelengths 400-500 nm and at very short wavelengths. Their visual sensitivity decreases more sharply at wavelengths >500 nm than it does at wavelengths more...
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- 2019
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10. Microperimetry in Three Inherited Retinal Disorders
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Ronald M. Hansen, Anne B. Fulton, and Laura Bagdonaite-Bejarano
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medicine.medical_specialty ,Retinal Disorder ,genetic structures ,Retinoschisis ,Fixation, Ocular ,Macular Degeneration ,03 medical and health sciences ,0302 clinical medicine ,Ophthalmology ,medicine ,Humans ,Stargardt Disease ,Clinical Trials as Topic ,Retina ,business.industry ,Outcome measures ,Small sample ,General Medicine ,medicine.disease ,Visual sensitivity ,Stargardt disease ,Clinical trial ,medicine.anatomical_structure ,030221 ophthalmology & optometry ,Visual Field Tests ,Visual Fields ,business ,Microperimetry ,Choroideremia ,030217 neurology & neurosurgery - Abstract
Objective: Microperimetry (MP) is used to assess visual sensitivity mediated by the central retina. As such, MP performance is a candidate outcome measure for gene therapy trials. Herein, we review MP results in three inherited retinal disorders for which gene therapy trials have been initiated-choroideremia, Stargardt disease, and X-linked juvenile retinoschisis. Each of these disorders typically presents in childhood and each has distinct effects on the central retina. Outcomes and Results: Our review indicates that microperimetry is feasible in each of these conditions. The MP sensitivity maps vary among conditions consistent with known effects of each of the three conditions. There is, however, within each of the three disorders considerable variability in fixation stability and in the pattern of sensitivity loss. Conclusions: Microperimetry is a valuable tool for monitoring functional aspects of central retina in an individual patient, especially in combination with other modalities such as OCT, autofluorescence, and acuity and thus may contribute to evaluating the efficacy of gene treatments. Variability of the MP parameters raises some cautions in application of MP as an outcome measure in treatment trials that may have small sample sizes. Nonetheless, we suspect that MP will continue to have a rightful place in future gene therapy trials. more...
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- 2019
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11. Significant correlations between focal photopic negative response and focal visual sensitivity and ganglion cell complex thickness in glaucomatous eyes
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Atsushi Tada, Tomoharu Nishimura, Mana Gonmori, Masahiko Ishizuka, Yuji Hara, Shigeki Machida, and Satoshi Ebihara
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Retinal Ganglion Cells ,medicine.medical_specialty ,genetic structures ,Open angle glaucoma ,Cell complex ,Glaucoma ,chemistry.chemical_compound ,Ophthalmology ,medicine ,Electroretinography ,Humans ,business.industry ,Retinal ,General Medicine ,medicine.disease ,Visual sensitivity ,eye diseases ,Ganglion ,medicine.anatomical_structure ,chemistry ,Visual Field Tests ,sense organs ,Visual Fields ,business ,Microperimetry ,Glaucoma, Open-Angle ,Tomography, Optical Coherence ,Photopic vision - Abstract
PURPOSE To determine whether there are significant correlations between the focal photopic negative response (PhNR), the focal visual sensitivity and the ganglion cell complex (GCC) thickness in glaucomatous eyes. STUDY DESIGN Single-center observational study. METHODS Fifty-two eyes of 52 patients (71.4 ± 9.42 years) with clinically diagnosed open angle glaucoma were studied. Thirty-six age-matched normal subjects served as controls. The focal PhNR of the focal macular electroretinograms (fmERGs) were elicited by a 15° circular, a superior semicircular or an inferior semicircular stimulus centered on the fovea. The thickness of the GCC was measured in the corresponding retinal areas in the spectral-domain optical coherence tomographic images. The visual sensitivities (dB) were measured by microperimetry at the retinal area where the fmERGs were elicited and were converted to liner values (1/Lambert). RESULTS The focal PhNR amplitudes were significantly correlated with the visual sensitivities of the full-circle (R = 0.532), the superior (R = 0.530) and inferior (R = 0.526) semicircular responses (P more...
- Published
- 2021
12. Landscape Visual Sensitivity Assessment of Historic Districts—A Case Study of Wudadao Historic District in Tianjin, China
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Jian Zeng, Aihemaiti Namaiti, and Ya-Nan Fang
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Index (economics) ,Geographic information system ,010504 meteorology & atmospheric sciences ,media_common.quotation_subject ,Geography, Planning and Development ,0211 other engineering and technologies ,lcsh:G1-922 ,02 engineering and technology ,historic district landscape ,01 natural sciences ,visual sensitivity ,Earth and Planetary Sciences (miscellaneous) ,Quality (business) ,Sensitivity (control systems) ,Computers in Earth Sciences ,Visibility ,0105 earth and related environmental sciences ,media_common ,business.industry ,Environmental resource management ,landscape assessment ,Wudadao ,021107 urban & regional planning ,Geography ,Scale (social sciences) ,Landscape assessment ,business ,Tourism ,lcsh:Geography (General) - Abstract
Against the backdrop of urban stock renewal, as the core area of a city rich in culture, aesthetics, and tourism resources, the assessment of landscape visual sensitivity of historic districts can provide an accurate, objective, and intuitive decision-making basis for the multi-purpose planning of districts. The main purpose of this study was to develop an assessment method based on the geographic information system (GIS) in order to make a visual sensitivity index map on a district scale. To this end, this study uses the multi-criteria evaluation (MCE) method, selects the visibility (VSv), the number of potential users (VSu), and remarkableness (VSe) as the main criteria, and constructs a comprehensive assessment model of the visual sensitivity of the historic landscape. The most well-protected Wudadao Historic District in Tianjin (Wudadao) was selected as the study area, and its visual sensitivity was assessed. The assessment results are divided into four levels: areas of high sensitivity, moderate sensitivity, low sensitivity, and very low sensitivity. Results indicate that after the optimization and improvement of the evaluation index for visual sensitivity of a large-scale forest landscape, it is feasible to evaluate the small-scale visual sensitivity of historic districts, the higher the sensitivity level, the more important it is to be protected, and the more cautious it should be in the renewal of districts, the higher the number of potential users, the higher the visual sensitivity level, and so on. Further attention needs to be paid to planning and design to improve visual quality. more...
- Published
- 2021
13. Two-photon visual sensitivity of cataract patients
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Katarzyna Komar, Bartosz L. Sikorski, Anna Matuszak, Maciej Wojtkowski, and Marcin Marzejon
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medicine.medical_specialty ,genetic structures ,Two-photon excitation microscopy ,Intraocular lenses ,business.industry ,Ophthalmology ,Refractive surgery ,medicine.medical_treatment ,medicine ,sense organs ,business ,Visual sensitivity ,eye diseases - Abstract
The two- and one-photon visual sensitivities (2phS and 1phS) of cataract patients were tested before and after IOL surgery. Mean change in 2phS was twice smaller than 1phS indicating that 2phS is less affected by cataract. more...
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- 2021
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14. Photosensitivity in Various Disease States
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Umberto Raucci, Pasquale Parisi, Melania Evangelisti, Giovanni Di Nardo, and Maria Pia Villa
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medicine.medical_specialty ,Visual perception ,genetic structures ,Photophobia ,autism spectrum disorder ,Disease ,Audiology ,Electroencephalography ,Photosensitivity ,h response ,medicine ,alzheimer disease ,adhd ,electroencephalography ,ictal epileptic headache ,intermittent photic stimulation (ips) ,panic disorders photic driving (pd) ,photoparoxysmal eeg response (ppr) ,Intermittent photic stimulation ,medicine.diagnostic_test ,business.industry ,Visual sensitivity ,eye diseases ,Visual evoked responses ,sense organs ,medicine.symptom ,business - Abstract
Photosensitivity or “visual sensitivity” is in the literature used in different ways: (1) the focal or generalized epileptiform EEG reaction to Intermittent Photic Stimulation (IPS) or other visual stimuli, so called photoparoxysmal response or PPR; (2) visual stimuli that provoke seizures in everyday life, such as flickering sunlight, TV, videogames or striped patterns; and (3) sensitivity to lights in terms of ocular discomfort or photophobia. The variability in photic driving as physiological visual evoked responses has intrigued scientists since the use of IPS in EEG clinical research and gave insight into pathophysiological mechanisms. more...
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- 2021
15. Photosensitive and Pattern-Sensitive Epilepsy: A Guide for Patients and Caregivers
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Athanasios Covanis and Jessica Solodar
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medicine.medical_specialty ,Epilepsy ,Visual perception ,business.industry ,Reflex Epilepsy ,Medicine ,Audiology ,business ,medicine.disease ,Visual sensitivity ,Pattern sensitivity ,Safety guidelines - Abstract
Photsensitive epilepsy is the most common type of reflex epilepsy. Seizures in people with photosensitive or patter-sensitive occur in response to specific visual stimuli such as strobe lights, or flashing computer graphics, or, in some people, fixed stripes and gemetric patterns. The risk of these seizures has grown due to the tremendous increse in electronic screen exposure in daily life. This guide describes photosensitivity and pattern sensitivity and how they are diagnosed, managed and treated. It provides patient and caregivers with recommendations regarding strategies and environmental modifications that can reduce seizures triggered by common visual stimuli. Cobalt blue eyeglasses or sunglasses are strongly recommended for seizure protection. more...
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- 2020
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16. Quantifying visual allodynia across migraine subtypes: the Leiden Visual Sensitivity Scale
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Matthijs J.L. Perenboom, Amir H Zamanipoor Najafabadi, Ronald Zielman, Johannes A. Carpay, and Michel D. Ferrari
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0301 basic medicine ,medicine.medical_specialty ,Photophobia ,Aura ,Visual sensitivity ,Audiology ,Allodynia ,03 medical and health sciences ,0302 clinical medicine ,Chronic Migraine ,medicine ,Ictal ,Migraine ,business.industry ,Construct validity ,Cortical excitability ,medicine.disease ,Migraine with aura ,030104 developmental biology ,Anesthesiology and Pain Medicine ,Neurology ,Neurology (clinical) ,medicine.symptom ,business ,030217 neurology & neurosurgery ,Research Paper - Abstract
Supplemental Digital Content is Available in the Text. Visual allodynia, the burden of hypersensitivity to light and patterns, is enhanced in migraine patients, particularly in those with migraine with aura and chronic migraine., Enhanced sensitivity to light (photophobia) and patterns is common in migraine and can be regarded as visual allodynia. We aimed to develop and validate a questionnaire to easily quantify sensitivity to light and patterns in large populations, and to assess and compare visual allodynia across different migraine subtypes and states. We developed the Leiden Visual Sensitivity Scale (L-VISS), a 9-item scale (score range 0-36 points), based on literature and patient interviews, and examined its construct validity. Furthermore, we assessed ictal and interictal visual sensitivity in episodic migraine with (n = 67) and without (n = 66) aura and chronic migraine with (n = 20) and without (n = 19) aura, and in healthy controls (n = 86). Differences between migraine subtypes and states were tested using a linear mixed model with 3 fixed factors (episodic/chronic, with/without aura, and ictal/interictal). Test–retest reliability and construct validity of L-VISS were good. Leiden Visual Sensitivity Scale scores correlated in the expected direction with light discomfort (Kendall's τ = −0.25) and pattern glare tests (τ = 0.35). Known-group comparisons confirmed its construct validity. Within migraine subtypes, L-VISS scores were higher in migraine with aura versus without aura and in chronic versus episodic migraine. The linear mixed model showed all factors affected the outcome (P < 0.001). The L-VISS is an easy-to-use scale to quantify and monitor the burden of bothersome visual sensitivity to light and patterns in large populations. There are remarkable ictal and interictal differences in visual allodynia across migraine subtypes, possibly reflecting dynamic differences in cortical excitability. more...
- Published
- 2018
17. Relationship of Macular Thickness and Function to Optical Microangiography Measurements in Glaucoma
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Srilakshmi Dasari, Robert N. Weinreb, Mohammed Riyazuddin, Harsha L. Rao, Narendra K. Puttaiah, Carroll A.B. Webers, Zia S. Pradhan, Kaweh Mansouri, RS: MHeNs - R3 - Neuroscience, Oogheelkunde, MUMC+: *MA Oogheelkunde (3), and MUMC+: MA UECM Oogartsen MUMC (9) more...
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Male ,Retinal Ganglion Cells ,primary open-angle glaucoma ,genetic structures ,Glaucoma ,PROGRESSION ,perfusion density ,optical microangiography ,Nerve Fibers ,0302 clinical medicine ,Macula Lutea ,VESSEL DENSITY ,RETINA ,Aged, 80 and over ,medicine.diagnostic_test ,Angiography ,Organ Size ,DEFECTS ,Middle Aged ,Visual sensitivity ,Visual field ,medicine.anatomical_structure ,COHERENCE TOMOGRAPHY ANGIOGRAPHY ,Female ,Visual field loss ,OPEN-ANGLE GLAUCOMA ,Glaucoma, Open-Angle ,Tomography, Optical Coherence ,Adult ,medicine.medical_specialty ,ganglion cell-inner plexiform layer thickness ,Open angle glaucoma ,VISUAL-FIELD LOSS ,03 medical and health sciences ,Optical coherence tomography ,Ophthalmology ,medicine ,Humans ,EYES ,HEALTHY ,Intraocular Pressure ,Aged ,vessel length density ,Retina ,PERIPAPILLARY ,business.industry ,medicine.disease ,eye diseases ,Cross-Sectional Studies ,Microangiography ,030221 ophthalmology & optometry ,sense organs ,business ,030217 neurology & neurosurgery - Abstract
Purpose:The purpose of this article was to evaluate the relationship between macular optical microangiography (OMAG), ganglion cell-inner plexiform layer (GCIPL) thickness, and visual sensitivity measurements of different macular sectors in primary open-angle glaucoma.Methods:In a cross-sectional study, 39 eyes of 26 primary open-angle glaucoma patients underwent optical coherence tomography imaging and 10-2 visual field examination of the macula in the same session. Linear regression models were used to evaluate the relationships between OMAG, GCIPL thickness, and visual sensitivity measurements in different macular sectors. Strength of relationship was reported as coefficient of determination (R-2).Results:R-2 values for the associations between OMAG and GCIPL thickness measurements ranged from 0.37 in the temporal sector to 0.56 in the inferior macular sector. R-2 values for the association between OMAG and visual sensitivity measurements ranged from 0.23 in the superior to 0.53 in the inferior macular sector. R-2 values for the association between GCIPL thickness and visual sensitivity measurements ranged from 0.15 in the superior to 0.62 in the temporal sector.Conclusions:The strongest associations between OMAG, GCIPL thickness, and visual sensitivity measurements were found in the inferior macular sector. The association of OMAG with GCIPL thickness measurements was as strong as the association between OMAG and visual sensitivity measurements in the inferior macular sector. more...
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- 2018
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18. Optimum Space-Frequency Partition in Subband Image Coding with Human Visual Sensitivity and Region-of-Interest
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Haruhiko Miyazaki and Masashi Kameda
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Image coding ,Region of interest ,Computer science ,business.industry ,Frequency partition of a graph ,Pattern recognition ,Artificial intelligence ,business ,Space (mathematics) ,Visual sensitivity - Published
- 2018
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19. Luminance modulations from eye movements predict visual sensitivity
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Janis Intoy, Martina Poletti, Michele Rucci, Norick R. Bowers, and Jonathan D. Victor
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Ophthalmology ,business.industry ,Computer science ,Eye movement ,Computer vision ,Artificial intelligence ,business ,Visual sensitivity ,Luminance ,Sensory Systems - Published
- 2021
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20. Visual sensitivity and reaction time measures show no evidence for purely exogenous object-based attention
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Martin Rolfs and Olga Shurygina
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Ophthalmology ,Computer science ,business.industry ,Computer vision ,Artificial intelligence ,business ,Visual sensitivity ,Sensory Systems ,Object-based attention - Published
- 2021
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21. Adaptive Optimization of Visual Sensitivity
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Sergei Gepshtein and Thomas D. Albright
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Multidisciplinary ,Adaptive optimization ,business.industry ,Computer science ,05 social sciences ,Sensory system ,Observer (special relativity) ,Machine learning ,computer.software_genre ,Visual sensitivity ,Article ,050105 experimental psychology ,03 medical and health sciences ,0302 clinical medicine ,Premise ,Normative ,Visual motion perception ,0501 psychology and cognitive sciences ,Artificial intelligence ,Environmental statistics ,business ,computer ,030217 neurology & neurosurgery - Abstract
Sensory systems adapt to environmental change. It has been argued that adaptation should have the effect of optimizing sensitivity to the new environment. Here we consider a framework in which this premise is made concrete using an economic normative theory of visual motion perception. In this framework, visual systems adapt to the environment by reallocating their limited neural resources. The allocation is optimal when uncertainties about different aspects of stimulation are balanced. This theory makes predictions about visual sensitivity as a function of environmental statistics. Adaptive optimization of the visual system should be manifested as a change in sensitivity for an observer and for the underlying motion-sensitive neurons. We review evidence supporting these predictions and examine effects of adaptation on the neuronal representation of visual motion. more...
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- 2017
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22. Saccadic Suppression Is Embedded Within Extended Oscillatory Modulation of Sensitivity
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Maria Concetta Morrone and Alessandro Benedetto
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Adult ,Male ,genetic structures ,Visual Acuity ,Visual oscillations ,Fixation, Ocular ,Sensorimotor integration ,Horizontal saccades ,050105 experimental psychology ,03 medical and health sciences ,0302 clinical medicine ,Biological Clocks ,Saccadic suppression of image displacement ,Long period ,Saccades ,Humans ,0501 psychology and cognitive sciences ,Contrast sensitivity ,Saccadic suppression ,Research Articles ,Communication ,Neuroscience (all) ,business.industry ,General Neuroscience ,05 social sciences ,Eye movement ,Neural Inhibition ,Action and perception ,Eye movements ,Visual sensitivity ,Saccadic masking ,Visual field ,Saccade ,action and perception ,contrast sensitivity ,eye movements ,saccadic suppression ,sensorimotor integration ,visual oscillations ,Female ,Psychology ,business ,Neuroscience ,Psychomotor Performance ,030217 neurology & neurosurgery - Abstract
Action and perception are intimately coupled systems. One clear case is saccadic suppression, the reduced visibility around the time of saccades, which is important in mediating visual stability; another is the oscillatory modulation of visibility synchronized with hand action. To suppress effectively the spurious retinal motion generated by the eye movements, it is crucial that saccadic suppression and saccadic onset be temporally synchronous. However, the mechanisms that determine this temporal synchrony are unknown. We investigated the effect of saccades on contrast discrimination sensitivity over a long period stretching over >1 s before and after saccade execution. Human subjects made horizontal saccades at will to two stationary saccadic targets separated by 20°. At a random interval, a brief Gabor patch was displayed between the two fixations in either the upper or lower visual field and the subject had to detect its location. Strong saccadic suppression was measured between −50 and 50 ms from saccadic onset. However, the suppression was systematically embedded in a trough of oscillations of contrast sensitivity that fluctuated rhythmically in the delta range (at ∼3 Hz), commencing ∼1 s before saccade execution and lasting for up to 1 s after the saccade. The results show that saccadic preparation and visual sensitivity oscillations are coupled and the coupling might be instrumental in temporally aligning the initiation of the saccade with the visual suppression.SIGNIFICANCE STATEMENTSaccades are known to produce a suppression of contrast sensitivity at saccadic onset and an enhancement after saccadic offset. Here, we show that these dynamics are systematically embedded in visual oscillations of contrast sensitivity that fluctuate rhythmically in the delta range (at ∼3 Hz), commencing ∼1 s before saccade execution and lasting for up to 1 s after the saccade. The results show that saccadic preparation and visual sensitivity oscillations are coupled and the coupling might be instrumental in aligning temporally the initiation of the saccade with the visual suppression. more...
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- 2017
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23. Photosensitivity in Dravet syndrome is under-recognized and related to prognosis
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Anja C M Sonsma, Al W. de Weerd, Dorothée G.A. Kasteleijn-Nolst Trenité, Nine V A M Knoers, Frans S. S. Leijten, Merel Wassenaar, Thea Gutter, W. Boudewijn Gunning, Jolien S. van Campen, Nienke E. Verbeek, Willy P. J. Spetgens, and Eva H. Brilstra more...
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0301 basic medicine ,Male ,Pathology ,Pediatrics ,Photic Stimulation ,Epilepsies, Myoclonic ,Electroencephalography ,Epilepsies ,Epilepsies, Myoclonic/complications ,0302 clinical medicine ,Reflex/diagnosis ,Intellectual disability ,Prevalence ,SCN1A ,Intermittent photic stimulation ,Child ,medicine.diagnostic_test ,Epilepsy, Reflex/diagnosis ,Visual sensitivity ,Sensory Systems ,Neurology ,Child, Preschool ,Female ,medicine.medical_specialty ,Adolescent ,Myoclonic/complications ,PPR ,Epilepsy, Reflex ,03 medical and health sciences ,Self-induction ,Dravet syndrome ,Pattern stimulation ,Physiology (medical) ,medicine ,Journal Article ,Humans ,Preschool ,Photoparoxysmal EEG response ,Epilepsy ,NAV1.1 Voltage-Gated Sodium Channel/genetics ,business.industry ,Self induction ,Infant ,medicine.disease ,NAV1.1 Voltage-Gated Sodium Channel ,030104 developmental biology ,Neurology (clinical) ,business ,030217 neurology & neurosurgery - Abstract
Objective: To detect determinants for photoparoxysmal EEG response (PPR) in SCN1A -related Dravet syndrome (DS). Methods: Data were studied from nationwide medical histories and EEGs of DS-patients ( n =53; 31 males, age 2–19years). Detailed questionnaires on visual stimuli were completed by parents ( n =49). Results: PPR was found in 22 patients (42%; median age 1.25yr), and repeatedly in 17%. PPR (17% of 249 intermittent photic stimulation (IPS)-EEGs) occurred more often with optimal IPS protocols (OR 2.11 [95%CI 1.09–4.13]) and in EEGs showing spontaneous epileptiform abnormalities (OR 5.08 [95%CI 2.05–12.55]). PPR-positive patients tended to be younger at first ( p =0.072) and second seizure ( p =0.049), showed severe intellectual disability ( p =0.042), and had more often spontaneous occipital epileptiform abnormalities ( p Clinical sensitivity was reported in medical files in 22% of patients and by parents in 43% (self-induction 24%). Clinical or EEG proven visual sensitivity was detected in 65% of cases. Conclusions: Sensitivity to visual stimuli is very common in DS and more often noticed by parents than confirmed by EEG. Detection of PPR improves with repetitive tests using accurate IPS protocols. Significance: Photosensitivity is an important feature in DS and seems to be a marker of the severity of the disorder. Therefore repeated standardized IPS should be encouraged. more...
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- 2017
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24. Quantification of photophobia in visual snow syndrome: A case-control study
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Andreas Straube, Christoph J. Schankin, Ruth Ruscheweyh, and Ozan Eren
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Adult ,Male ,Migraine without Aura ,medicine.medical_specialty ,Photophobia ,Migraine with Aura ,Audiology ,Visual processing ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Medicine ,Humans ,030304 developmental biology ,0303 health sciences ,business.industry ,General Medicine ,Visual snow ,Syndrome ,Middle Aged ,Visual sensitivity ,Visual Disturbance ,Case-Control Studies ,Female ,Neurology (clinical) ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
Objective To quantify photophobia in visual snow syndrome (VSS), a debilitating migraine-associated visual disturbance manifesting with continuous “TV snow-like” flickering dots in the entire visual field and additional visual symptoms, such as photophobia. Methods Photophobia was compared between 19 patients with VSS and 19 controls matched for age, sex, migraine and aura using the Leiden Visual Sensitivity Scale (L-VISS). Results Patients with VSS had an increased L-VISS-score compared to matched controls [(22.2 ± 5.9 vs. 4.4 ± 4.8; ANOVA, factors VSS and comorbid migraine: Main effect for VSS (F = 100.70; p Conclusion Patients with VSS suffer continuously from photophobia at a level similar to chronic migraineurs during attacks. Although migraine and VSS share dysfunctional visual processing, patients with VSS might be more severely affected. more...
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- 2019
25. Efficient coding of natural scene statistics predicts discrimination thresholds for grayscale textures
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Tiberiu Tesileanu, Jonathan D. Victor, Vijay Balasubramanian, Mary M. Conte, Ann M Hermundstad, and John J Briguglio
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0301 basic medicine ,Adult ,Male ,Light ,QH301-705.5 ,Science ,efficient coding ,Physics of Living Systems ,Grayscale ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Salience (neuroscience) ,psychophysics ,natural images ,Psychophysics ,Humans ,Biology (General) ,Mathematics ,texture perception ,General Immunology and Microbiology ,business.industry ,General Neuroscience ,Binary image ,Scene statistics ,Pattern recognition ,General Medicine ,Limiting ,Middle Aged ,Visual sensitivity ,030104 developmental biology ,Pattern Recognition, Visual ,Salient ,FOS: Biological sciences ,Quantitative Biology - Neurons and Cognition ,Medicine ,Neurons and Cognition (q-bio.NC) ,Female ,Artificial intelligence ,business ,Research Advance ,030217 neurology & neurosurgery ,Photic Stimulation ,Coding (social sciences) ,Neuroscience ,Human - Abstract
Previously, in (Hermundstad et al., 2014), we showed that when sampling is limiting, the efficient coding principle leads to a "variance is salience" hypothesis, and that this hypothesis accounts for visual sensitivity to binary image statistics. Here, using extensive new psychophysical data and image analysis, we show that this hypothesis accounts for visual sensitivity to a large set of grayscale image statistics at a striking level of detail, and also identify the limits of the prediction. We define a 66-dimensional space of local grayscale light-intensity correlations, and measure the relevance of each direction to natural scenes. The "variance is salience" hypothesis predicts that two-point correlations are most salient, and predicts their relative salience. We tested these predictions in a texture-segregation task using un-natural, synthetic textures. As predicted, correlations beyond second order are not salient, and predicted thresholds for over 300 second-order correlations match psychophysical thresholds closely (median fractional error, 33 pages, 12 figures more...
- Published
- 2019
26. A HVS-Inspired Attention to Improve Loss Metrics for CNN-Based Perception-Oriented Super-Resolution
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Juan Luis Gonzalez Bello, Munchurl Kim, and Taimoor Tariq
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FOS: Computer and information sciences ,Visual perception ,Computer science ,business.industry ,Computer Vision and Pattern Recognition (cs.CV) ,media_common.quotation_subject ,Computer Science - Computer Vision and Pattern Recognition ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Pattern recognition ,Visual sensitivity ,Convolutional neural network ,Visualization ,Feature (computer vision) ,Perception ,Human visual system model ,Artificial intelligence ,business ,Image restoration ,media_common - Abstract
Deep Convolutional Neural Network (CNN) features have been demonstrated to be effective perceptual quality features. The perceptual loss, based on feature maps of pre-trained CNN's has proven to be remarkably effective for CNN based perceptual image restoration problems. In this work, taking inspiration from the the Human Visual System (HVS) and visual perception, we propose a spatial attention mechanism based on the dependency human contrast sensitivity on spatial frequency. We identify regions in input images, based on the underlying spatial frequency, which are not generally well reconstructed during Super-Resolution but are most important in terms of visual sensitivity. Based on this prior, we design a spatial attention map that is applied to feature maps in the perceptual loss and its variants, helping them to identify regions that are of more perceptual importance. The results demonstrate the our technique improves the ability of the perceptual loss and contextual loss to deliver more natural images in CNN based super-resolution. more...
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- 2019
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27. MEASUREMENTS OF INTRAOCULAR STRAYLIGHT, VISUAL SENSITIVITY, AND DISCOMFORT GLARE FOR YOUNG AND ELDERLY OBSERVERS
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Tomoharu Ishikawa, Kazuhiko Ohnuma, Nao Tsuchiya, Miyoshi Ayama, and Yuki Tachikawa
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business.industry ,Optometry ,Glare (vision) ,Medicine ,business ,Visual sensitivity - Published
- 2019
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28. Evaluation of Landscape Resources of Urban Forest Park Based on GIS – Take Beijing Tongzhou Grand Canal Forest Park as an Example
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Sheng Lu and YanYi Lyu
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Resource (biology) ,Geographic information system ,business.industry ,020208 electrical & electronic engineering ,05 social sciences ,Environmental resource management ,0507 social and economic geography ,Elevation ,02 engineering and technology ,Visual sensitivity ,Grand canal ,Geography ,Urban forest ,Beijing ,Ecotourism ,0202 electrical engineering, electronic engineering, information engineering ,business ,050703 geography - Abstract
Urban forest parks are different from urban parks and forest parks. They are located in the central area or suburbs of the city. They are supported by forest ecological landscapes, supplemented by man-made natural landscapes, and provide the citizens with a place for forest ecotourism, which has certain special characteristics. Therefore, the evaluation of landscape resources of urban forest parks can objectively analyze the landscape effects of urban forest parks. This paper takes Beijing Tongzhou Grand Canal Forest Park as an example. Based on the basic geographic data combined with DEM as the data foundation, the ENVI software and Arc GIS software are used as the specific implementation platform to select the representative forest park 18 scenes. Quantitative analysis of slope, aspect, elevation, and landscape visual sensitivity. Finally, it was found that the scenic spots of scenic spot 2, scenic spot 4 and scenic spot 15 were lower; the scenic spots 1, scenic spots 6, and scenic spots 14 and 18 scored higher. This verifies the feasibility of applying GIS technology in landscape resource evaluation of urban forest parks, and provides reference and basis for landscape resource evaluation techniques in similar areas. more...
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- 2019
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29. Association of Intereye Visual-Sensitivity Asymmetry With Progression of Primary Open-Angle Glaucoma
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Young Kook Kim, Eunoo Bak, Jin Wook Jeoung, Jinho Lee, Ahnul Ha, Sung Uk Baek, Young Soo Han, Ki Ho Park, Jin Soo Kim, and Yong Woo Kim
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Adult ,Male ,hemifield ,medicine.medical_specialty ,Time Factors ,primary open-angle glaucoma ,genetic structures ,Open angle glaucoma ,Optic Disk ,Glaucoma ,Nerve Fibers ,Hazard modeling ,visual field defect ,Ophthalmology ,Humans ,Medicine ,Significant risk ,Asymmetry Index ,Intraocular Pressure ,Aged ,Retrospective Studies ,Aged, 80 and over ,business.industry ,Middle Aged ,Prognosis ,medicine.disease ,Visual sensitivity ,intereye ,eye diseases ,Visual field ,Absolute deviation ,Disease Progression ,asymmetric ,Visual Field Tests ,Female ,sense organs ,Visual Fields ,business ,Glaucoma, Open-Angle ,Tomography, Optical Coherence ,Follow-Up Studies - Abstract
Purpose To investigate the relationship between intereye visual field defect (VFD) asymmetry and subsequent VF progression in primary open-angle glaucoma (POAG). Methods Moderate-stage patients with POAG (226 eyes of 113 patients) with a single hemifield defect were followed for 8.7 years. Participants were categorized into three groups by initial VF pattern: (1) unilateral VFD, (2) bilateral VFD within same hemifield (superior–superior, inferior–inferior), (3) bilateral VFD within opposite hemifield (superior–inferior). The mean deviation (MD) difference between the intereye was defined as the intereye MD asymmetry index (iMAI). Intereye visual-sensitivity difference within the same hemifield was calculated as the intereye hemifield visual-sensitivity asymmetry index. Functional progression was detected by Glaucoma Progression Analysis. The overall rate of MD change and the association between new indices were evaluated by linear regression. A Kaplan-Meier survival analysis was performed and the factors associated with glaucoma progression were evaluated by Cox proportional hazard modeling. Results Unilateral VFD eyes and bilateral VFD eyes within opposite VF hemifield showed significant progression and faster rate of MD change compared with bilateral VFD eyes within same VF hemifield (71.1% vs. 45.9% vs. 21.1% [P = 0.001]; –1.27 dB/y vs. −0.64 dB/y vs. −0.32 dB/y [P = 0.001]). Unilateral VFD eyes showed the fastest time to VF progression compared with other groups (P = 0.002). A faster rate of MD change was associated with greater intereye MD asymmetry index (P = 0.001) and greater intereye hemifield visual-sensitivity asymmetric index (P = 0.031), which were significant risk factors for glaucoma progression (all P < 0.001). Conclusions Among POAG eyes with comparable hemifield VFDs, eyes without a corresponding hemifield defect in the fellow eye showed faster rates of progression compared with those with a corresponding hemifield defect. more...
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- 2021
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30. Validation of the Leiden Visual Sensitivity Scale and Visual Discomfort Scale in Chronic Pain Conditions
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Ten Brink, Antonia F., Proulx, Michael J., Bultitude, Janet H., Leerstoel Stigchel, Leerstoel Dijkerman, Helmholtz Institute, Experimental Psychology (onderzoeksprogramma PF), Afd Psychologische functieleer, Leerstoel Stigchel, Leerstoel Dijkerman, Helmholtz Institute, Experimental Psychology (onderzoeksprogramma PF), and Afd Psychologische functieleer more...
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medicine.medical_specialty ,Central sensitization ,Visual perception ,genetic structures ,Visual Discomfort ,Experimental and Cognitive Psychology ,03 medical and health sciences ,0302 clinical medicine ,Physical medicine and rehabilitation ,030202 anesthesiology ,Artificial Intelligence ,Fibromyalgia ,medicine ,Humans ,pattern glare ,business.industry ,Chronic pain ,medicine.disease ,Scale (music) ,Visual sensitivity ,Sensory Systems ,Ophthalmology ,Complex regional pain syndrome ,Complex Regional Pain Syndrome ,visual allodynia ,fibromyalgia ,Chronic Pain ,business ,visual stress ,Complex Regional Pain Syndromes ,030217 neurology & neurosurgery - Abstract
Discomfort provoked by normally innocuous visual stimuli has been reported by people with chronic pain. Visual discomfort may be higher in pain conditions in which central sensitization is implicated, such as Complex Regional Pain Syndrome (CRPS) and fibromyalgia. In an online study, we validated the Leiden Visual Sensitivity Scale (L-VISS) and Visual Discomfort Scale (VDS) in people with CRPS ( n = 57), fibromyalgia ( n = 75), and general chronic pain ( n = 53); investigated whether these groups and pain-free controls ( n = 125) differed in visual discomfort; and evaluated the effect of age. The L-VISS and VDS had good internal consistency. Both scales were positively related with experimentally induced visual distortions for mid-spatial frequency striped patterns, suggesting good construct validity. The scales were positively related with each other, and dissociated between the pain and pain-free groups in similar ways, suggesting good construct validity. There was no relationship between age and L-VISS scores and a small negative relationship between age and VDS scores. Visual discomfort was highest in the fibromyalgia group, followed by the CRPS group. This research confirms the utility of the L-VISS and VDS for measuring visual sensitivity in chronic pain and adds to evidence that central sensitization is an important mechanism of visual discomfort. more...
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- 2021
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31. Abnormal visual sensitivity in eyelid myoclonia with absences: Evidence from electrocortical connectivity and non-linear quantitative analysis of EEG signal
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Alessandra Nicoletti, Loretta Giuliano, Vito Sofia, Greta Mainieri, Mario Zappia, Daniela Fatuzzo, and Giovanni Mostile
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Myoclonus ,medicine.medical_specialty ,Alpha (ethology) ,Epilepsies, Myoclonic ,Audiology ,Electroencephalography ,Epilepsy, Reflex ,03 medical and health sciences ,Epilepsy ,0302 clinical medicine ,Medicine ,Humans ,Resting state fMRI ,medicine.diagnostic_test ,business.industry ,Eyelids ,General Medicine ,medicine.disease ,Visual sensitivity ,eye diseases ,Frontal Lobe ,Electrophysiology ,Neurology ,Frontal lobe ,Epilepsy, Absence ,Epilepsy, Generalized ,Neurology (clinical) ,Occipital Lobe ,business ,Occipital lobe ,030217 neurology & neurosurgery - Abstract
Purpose Eyelid myoclonia with absences (EMA) is an epileptic syndrome characterized by eyelid myoclonia with or without absences, eyes closure-induced EEG paroxysms and photosensitivity. Pathophysiological mechanisms of visual sensitivity in EMA are not-fully understood. The objective of the present study was to analyze the electrophysiological dynamics implicated in the visual sensitivity in patients with EMA. Methods We analyzed data of 10 subjects with diagnosis of EMA and of 10 healthy control subjects. For both patients and controls, 4-seconds artifacts-free electroencephalographic signal epochs recorded were analyzed, during resting state, eyes-opened and eyes-closed tasks. Resting state networks in EEG have been computed using independent components analysis (ICA) LORETA. Moreover, the power law exponent β was obtained for each coordinate as minus the slope of the power spectrum versus frequency in a Log-Log scale. Results Using LORETA ICA, patients during resting state showed significant differences as compared to controls with a reduction of the physiological alpha activity over the occipital lobe and of the physiological beta activity over the frontal lobe. Immediately after eye closure, a significant increase of beta activity over the frontal lobe was found in the group of patients compared to controls. Power law exponent β analysis showed a significant increase of β over the frontal regions in patients as compared to controls during resting-state and an increase of β over the parieto-occipital regions after eye closure. Conclusion Abnormal occipital and frontal cortex activities seem to be related with the visual sensitivity and eyelid myoclonia observed in patients with EMA. more...
- Published
- 2019
32. Perceptual model optimized efficient foveated rendering
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Wenxin Yu, Yinwei Zhan, Zhuo Yang, Zipeng Zheng, and Yuqing Li
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Visual perception ,Computer science ,business.industry ,media_common.quotation_subject ,05 social sciences ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,020207 software engineering ,02 engineering and technology ,Virtual reality ,Frame rate ,Visual sensitivity ,050105 experimental psychology ,Rendering (computer graphics) ,Computer graphics ,Perception ,0202 electrical engineering, electronic engineering, information engineering ,0501 psychology and cognitive sciences ,Computer vision ,Artificial intelligence ,business ,ComputingMethodologies_COMPUTERGRAPHICS ,media_common - Abstract
Higher resolution, wider FOV and increasing frame rate of HMD are demanding more VR computing resources. Foveated rendering is a key solution to these challenges. This paper introduces a perceptual model optimized foveated rendering. Tessellation levels and culling areas are adaptively adjusted based on visual sensitivity. We improve rendering performance while satisfying visual perception. more...
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- 2018
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33. Clinical treatment of traumatic optic neuropathy in children: Summary of 29 cases
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Na Li, Min Chen, Yan Jiang, and Jisheng Zhang
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Cancer Research ,Pediatrics ,medicine.medical_specialty ,Visual acuity ,business.industry ,Decompression ,Traumatic optic neuropathy ,General Medicine ,Visual sensitivity ,03 medical and health sciences ,0302 clinical medicine ,Pharmacotherapy ,Immunology and Microbiology (miscellaneous) ,030221 ophthalmology & optometry ,medicine ,Proper treatment ,General anaesthesia ,medicine.symptom ,business ,Clinical treatment ,030217 neurology & neurosurgery - Abstract
Clinical features and treatments for traumatic optic neuropathy (TON) in children are reported. Twenty-nine children were enrolled in the Affiliated Hospital of Qingdao University from April 1999 to May 2015 for retrospective analysis. Of these 29 patients, 5 received drug therapy, and 24 received drug therapy combined with surgical therapy. Among the patients who received surgical therapy, 23 received nasal endoscopic optic decompression under general anaesthesia, and 1 received nasal endoscopic orbital decompression under general anaesthesia. All the patients were followed up for at least 6 months. In 29 cases, 48.28% (14/29) had visual improvement. Of the 5 patients who received drug therapy, 3 showed improvement (60%). Of the 24 cases who received drug and surgical therapy, 11 showed improvement (45.83%). Of the 22 patients who lost visual sensitivity, 10 showed improvement (45.45%). Of the 7 cases with visual acuity above basic light sensitivity, 4 showed improvement (57.14%). In conclusion, TON in children can lead to poor diagnosis and prognosis because of the difficulty of examining children and their limited language expression ability. Early ophthalmologic examination is therefore essential for children with craniofacial injuries, and proper treatment should be undertaken as soon as possible. more...
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- 2018
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34. Macular thickness as a predictor of loss of visual sensitivity in ethambutol-induced optic neuropathy
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Bing Chen, Bing-jian Yang, Mo Yang, Qiu-hong Wang, Ai-di Zhang, Chunxia Peng, and Shihui Wei
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medicine.medical_specialty ,genetic structures ,Nerve fiber layer ,ethambutol ,lcsh:RC346-429 ,macular thickness ,Optic neuropathy ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Developmental Neuroscience ,Optical coherence tomography ,ethambutol-induced optic neuropathy1 ,visual sensitivity ,Ophthalmology ,peripapillary retinal nerve fiber layer ,Medicine ,In patient ,nerve regeneration ,lcsh:Neurology. Diseases of the nervous system ,Ethambutol ,optical coherence tomography ,medicine.diagnostic_test ,business.industry ,Retinal ,medicine.disease ,Visual sensitivity ,eye diseases ,Surgery ,ethambutol-induced optic neuropathy ,neural regeneration ,medicine.anatomical_structure ,chemistry ,030221 ophthalmology & optometry ,Optic nerve ,sense organs ,business ,030217 neurology & neurosurgery ,medicine.drug ,Research Article - Abstract
Ethambutol is a common cause of drug-related optic neuropathy. Prediction of the onset of ethambutol-induced optic neuropathy and consequent drug withdrawal may be an effective method to stop visual loss. Previous studies have shown that structural injury to the optic nerve occurred earlier than the damage to visual function. Therefore, we decided to detect structural biomarkers marking visual field loss in early stage ethambutol-induced optic neuropathy. The thickness of peripapillary retinal nerve fiber layer, macular thickness and visual sensitivity loss would be observed in 11 ethambutol-induced optic neuropathy patients (22 eyes) using optical coherence tomography. Twenty-four healthy age- and sex-matched participants (48 eyes) were used as controls. Results demonstrated that the temporal peripapillary retinal nerve fiber layer thickness and average macular thickness were thinner in patients with ethambutol-induced optic neuropathy compared with healthy controls. The average macular thickness was strongly positively correlated with central visual sensitivity loss (r (2) =0.878, P=0.000). These findings suggest that optical coherence tomography can be used to efficiently screen patients. Macular thickness loss could be a potential factor for predicting the onset of ethambutol-induced optic neuropathy. more...
- Published
- 2016
35. Zoning classes for forest visual landscape management in and around Pyeongchang Winter Olympic area: focused on Alpensia district in the city of Pyeongchang, Gangwon-do
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Hyun-Chul Park, Jung-Hwan Lee, and Gwan-Gyu Lee
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Buffer zone ,business.industry ,Ecology ,Forest management ,Forest landscape ,Forestry ,Management, Monitoring, Policy and Law ,Landscape design ,Visual sensitivity ,Altitude ,Geography ,Physical geography ,Zoning ,business - Abstract
Korea is preparing to host the 2018 Winter Olympics in Pyeongchang. The region surrounding Pyeongchang mostly consists of forested areas. To manage this region, it is necessary to design a process designating different management areas such as those allowing the formation of artificial and concentrated landscapes and restricted areas for conservation of the landscape. This study identifies methods for analyzing the degree of forest landscape management and level of visual sensitivity and subdivides the visible areas surrounding the region where the Winter Olympics will be held into different classes. As a result, four different classes were subdivided and the areas were divided into conservation zones, buffer zone 1, buffer zone 2, and transitional zones. The areas in the fourth class (transitional zone), where artificial and aggressive forest landscape management is possible, were primarily subjected to frequent movement and high levels of use. These areas included roads, city streets, areas surrounding ... more...
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- 2015
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36. Action capability enhances visual sensitivity in the extrapersonal space
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Do Joon Yi and Baek, Jongsoo
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Action (philosophy) ,business.industry ,Computer science ,Computer vision ,Artificial intelligence ,Space (mathematics) ,business ,Visual sensitivity - Published
- 2015
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37. Correlation between macular blood flow and central visual sensitivity in retinitis pigmentosa
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Yasuhiro Ikeda, Toshio Hisatomi, Noriko Yoshida, Tatsuro Ishibashi, Hiroshi Enaida, Shunji Nakatake, Kota Fujiwara, Masato Akiyama, Shoji Notomi, Yusuke Murakami, and Takahiro Nabeshima
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Adult ,Male ,medicine.medical_specialty ,Visual acuity ,Adolescent ,genetic structures ,Visual Acuity ,Blood Pressure ,Correlation ,Young Adult ,chemistry.chemical_compound ,Ophthalmology ,Retinitis pigmentosa ,Electroretinography ,Laser-Doppler Flowmetry ,Humans ,Medicine ,In patient ,Intraocular Pressure ,Aged ,Retrospective Studies ,business.industry ,Retinal Vessels ,Retinal ,General Medicine ,Blood flow ,Middle Aged ,Control subjects ,medicine.disease ,Visual sensitivity ,eye diseases ,chemistry ,Regional Blood Flow ,Visual Field Tests ,Optometry ,Female ,sense organs ,Visual Fields ,medicine.symptom ,business ,Blood Flow Velocity ,Retinitis Pigmentosa - Abstract
Purpose To investigate the changes in macular blood flow and the correlation between those changes and central visual function in patients with retinitis pigmentosa (RP). Methods The mean blur rate (MBR), a quantitative blurring index of the laser speckle pattern that represents retinal and choroidal blood flow, was measured by laser speckle flowgraphy. Mean blur rate values in the macular area were compared between 70 patients with RP and 28 control subjects. The relationships between MBR on the one hand and, on the other, visual acuity (VA), mean deviation (MD) and averaged macular sensitivity of static perimetry tests (Humphrey Filed Analyzer, the central 10-2 program) were analysed in patients with RP. Results Macular MBR was decreased to 75% in patients with RP compared with control subjects (p more...
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- 2015
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38. Central visual field sensitivity data from microperimetry with spatially dense sampling
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Andrew T. Astle, Iram Ali, and Jonathan Denniss
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Computer science ,lcsh:Computer applications to medicine. Medical informatics ,Microperimetry ,Multivariate interpolation ,03 medical and health sciences ,0302 clinical medicine ,Computer vision ,Central visual field ,lcsh:Science (General) ,Data Article ,Perimetry ,Multidisciplinary ,business.industry ,Age-related macular degeneration ,Eye movement ,Visual field ,Visual sensitivity ,Fixation (visual) ,030221 ophthalmology & optometry ,lcsh:R858-859.7 ,Artificial intelligence ,Normal vision ,business ,030217 neurology & neurosurgery ,lcsh:Q1-390 - Abstract
Microperimetry, also referred to as fundus perimetry or fundus-driven perimetry, enables simultaneous acquisition of visual sensitivity and eye movement data. We present sensitivity data collected from 60 participants with normal vision using gaze-contingent perimetry. A custom designed spatially dense test grid was used to collect data across the visual field within 13° of fixation. These data are supplemental to a study in which we demonstrated a spatial interpolation method that facilitates comparison of acquired data from any set of spatial locations to normative data and thus screening of individuals with both normal and non-foveal fixation “Methods for normative data comparison in gaze-contigent microperimetry” (Denniss and Astle, 2016) [1]. more...
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- 2016
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39. Visual attention is not always spatially coupled to subsequent oculomotor program
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Heiner Deubel, Luca Wollenberg, and Martin Szinte
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Cued speech ,Dissociation (neuropsychology) ,business.industry ,Covert ,Saccade ,Facilitation ,Visual attention ,Computer vision ,Artificial intelligence ,business ,Psychology ,Visual sensitivity ,Cognitive psychology - Abstract
The premotor theory of attention postulates that spatial attention arises from the activation of saccade areas and that the deployment of attention is the consequence of motor programming. Yet, attentional and oculomotor processes have been shown to be dissociable at the neuronal level in covert attention tasks. To investigate a potential dissociation at the behavioral level, we instructed human participants to saccade towards one of two nearby, competing saccade cues. The spatial distribution of visual attention was determined using oriented Gabor stimuli presented either at the cue locations, between them or at several other equidistant locations. Results demonstrate that accurate saccades towards one of the cues were associated with presaccadic enhancement of visual sensitivity at the respective saccade endpoint compared to the non-saccaded cue location. In contrast, averaging saccades, landing between the two cues, were not associated with attentional facilitation at the saccade endpoint, ruling out an obligatory coupling of attentional deployment to the oculomotor program. Rather, attention before averaging saccades was equally distributed to the two cued locations. Taken together, our results reveal a spatial dissociation of visual attention and saccade programming. They suggest that the oculomotor program depends on the state of attentional selection before saccade onset, and that saccade averaging arises from unresolved attentional selection. more...
- Published
- 2017
- Full Text
- View/download PDF
40. Test and Analysis of Chinese Coal Miners’ Vision Ability
- Author
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Feng Wu and Mingming Deng
- Subjects
genetic structures ,business.industry ,Coal mining ,Adaptation (eye) ,Flicker fusion threshold ,Visual sensitivity ,eye diseases ,Color discrimination ,Coal ,Response ability ,business ,Psychology ,Depth perception ,Cognitive psychology - Abstract
Two hundred and thirty-nine coal miners’ vision, color discrimination, dark adaptation, depth perception, vision response time and Critical Flicker Fusion Frequency (CFF) were tested. The results showed that, with the age increasing, the coal miners’ dark adaptation ability, vision response ability and visual sensitivity declined; there were significant differences in vision response ability and visual sensitivity from different types of work; the miners with better vision had stronger dark adaptation ability and visual sensitivity; the miners with stronger dark adaptation ability had stronger visual sensitivity. In the end, some proposals were given to coal miner selection and management. more...
- Published
- 2017
- Full Text
- View/download PDF
41. The Verriest Lecture: Adventures in blue and yellow
- Author
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Michael A. Webster
- Subjects
Color difference ,Color vision ,business.industry ,media_common.quotation_subject ,Color space ,Visual sensitivity ,Article ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Variation (linguistics) ,Optics ,Perception ,Neural processing ,Computer Vision and Pattern Recognition ,Psychology ,business ,Cognitive psychology ,media_common ,Hue - Abstract
Conventional models of color vision assume that blue and yellow (along with red and green) are the fundamental building blocks of color appearance, yet how these hues are represented in the brain and whether and why they might be special are questions that remain shrouded in mystery. Many studies have explored the visual encoding of color categories, from the statistics of the environment to neural processing to perceptual experience. Blue and yellow are tied to salient features of the natural color world, and these features have likely shaped several important aspects of color vision. However, it remains less certain that these dimensions are encoded as primary or “unique” in the visual representation of color. There are also striking differences between blue and yellow percepts that may reflect high-level inferences about the world, specifically about the colors of light and surfaces. Moreover, while the stimuli labeled as blue or yellow or other basic categories show a remarkable degree of constancy within the observer, they all vary independently of one another across observers. This pattern of variation again suggests that blue and yellow and red and green are not a primary or unitary dimension of color appearance, and instead suggests a representation in which different hues reflect qualitatively different categories rather than quantitative differences within an underlying low-dimensional “color space.” more...
- Published
- 2020
- Full Text
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42. The taste and visual sensitivity research based on arrangement of colors - The main item is the Korean traditional five-cardinal-colors
- Author
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Son, Wonjun
- Subjects
Communication ,business.industry ,Taste (sociology) ,media_common.quotation_subject ,Research based ,Sensitivity (control systems) ,Psychology ,business ,Visual sensitivity ,media_common ,Cognitive psychology - Published
- 2014
- Full Text
- View/download PDF
43. GIS-Based Multi-Criteria Assessment and Seasonal Impact on Plantation Forest Landscape Visual Sensitivity
- Author
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Zhidong Zhang, Xuanrui Huang, Huijuan Yang, Zhongqi Xu, and Yongning Li
- Subjects
MCE ,Geographic information system ,010504 meteorology & atmospheric sciences ,AHP ,seasonality ,business.industry ,Forest management ,Analytic hierarchy process ,Forestry ,Context (language use) ,lcsh:QK900-989 ,Vegetation ,010501 environmental sciences ,GIS ,01 natural sciences ,Geography ,Aerial photography ,visual sensitivity ,lcsh:Plant ecology ,plantation forest landscape ,Digital elevation model ,business ,Scale (map) ,Cartography ,0105 earth and related environmental sciences - Abstract
Visual sensitivity assessments identify the location of the high-sensitivity areas in terms of visual change. Studying the visual sensitivity of plantation forest landscapes and their seasonal changes can help resolve increasingly frequent conflicts between tourism and forest management activities, in the context of the multi-functional management of plantation forests. In this study, we used the geographic information system (GIS) and multi-criteria evaluation (MCE) methods combined with the analytic hierarchy process (AHP) to perform a visual sensitivity evaluation. Nine map-based criteria were selected, and the visual sensitivity of summer and autumn values were calculated, using data from sources including inventory data for forest management planning and design, digital elevation model (DEM), and aerial photographs. Vegetation uniformity (VU) and color diversity (CD) indices were constructed using three patch-level-based landscape indices, including area (AREA), fractal dimension index (FRAC), and proximity (PROX), to visualize the summer and autumn vegetation characteristics of a plantation forest landscape. We conducted a case study on the Saihanba Mechanical Forest Plantation, China&rsquo, s largest forest plantation. The results were evaluated by experts, confirming the method to be reliable. This study provides an accurate, objective, and visualized evaluation method for the visual sensitivity of plantations for forest management units at the landscape scale. In analyzing the visual sensitivity of plantation forest landscapes, appropriate criteria (e.g., uniformity or diversity should be selected based on forest vegetation characteristics). When identifying high-sensitivity regions, it is necessary to simultaneously analyze areas with high visual sensitivity in different seasons and then superimpose the results. more...
- Published
- 2019
- Full Text
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44. An Optimal Tchebichef Moment Quantization Using Psychovisual Threshold for Image Compression
- Author
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Nur Azman Abu, Nanna Suryana, and Ferda Ernawan
- Subjects
Health (social science) ,General Computer Science ,General Mathematics ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Data_CODINGANDINFORMATIONTHEORY ,Huffman coding ,Education ,symbols.namesake ,Redundancy (information theory) ,medicine ,Computer vision ,Quantization (image processing) ,General Environmental Science ,Mathematics ,Colour image ,business.industry ,General Engineering ,Visual sensitivity ,General Energy ,medicine.anatomical_structure ,symbols ,Bit-length ,Human eye ,Artificial intelligence ,business ,Image compression - Abstract
Colour image carries a certain amount of perceptual redundancy for the human eyes. The human eye is capable of perceiving various levels of colours. The sensitivity of human eye is useful for perceptual visual quality image in image compression. The visual sensitivity of the colour image in terms of image compression can be measured by a psychovisual threshold to generate the quantization tables. This paper will investigate a psychovisual threshold level for Tchebichef moment transform (TMT) from the contribution of its moments. In this paper presents a new technique to generate quantization table for TMT image compression based on psychovisual error threshold. The experimental results show that these new finer quantization tables based on psychovisual threshold for TMT provides better quality image and lower average bit length of Huffman code than previously proposed TMT quantization. more...
- Published
- 2014
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- View/download PDF
45. Iterative filtering algorithm for color image based on visual sensitivity and improved directional distance
- Author
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Gaoxi Li, Hua Li, Fuyuan Zhang, and Jun Cao
- Subjects
business.industry ,Computer science ,Color image ,Pattern recognition ,Computer vision ,Artificial intelligence ,Iterative filtering ,business ,Visual sensitivity - Published
- 2013
- Full Text
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46. Visual Sensitivity Shifts with Perceived Eye Position
- Author
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Bartholomäus Odoj and Daniela Balslev
- Subjects
Adult ,Male ,medicine.medical_specialty ,Eye Movements ,Cognitive Neuroscience ,Audiology ,Stimulus (physiology) ,Somatosensory system ,Young Adult ,Reaction Time ,medicine ,Humans ,Attention ,Vision, Ocular ,Visual search ,Communication ,Proprioception ,Postcentral gyrus ,business.industry ,Superior colliculus ,Transcranial Magnetic Stimulation ,Visual sensitivity ,Gaze ,Visual Perception ,Female ,business ,Psychology ,Photic Stimulation - Abstract
Spatial attention can be defined as the selection of a location for privileged stimulus processing. Most oculomotor structures, such as the superior colliculus or the FEFs, play an additional role in visuospatial attention. Indeed, electrical stimulation of these structures can cause changes in visual sensitivity that are location specific. We have proposed that the recently discovered ocular proprioceptive area in the human postcentral gyrus (S1EYE) may have a similar function. This suggestion was based on the observation that a reduction of excitability in this area with TMS causes not only a shift in perceived eye position but also lateralized changes in visual sensitivity. Here we investigated whether these shifts in perceived gaze position and visual sensitivity are spatially congruent. After continuous theta burst stimulation over S1EYE, participants underestimated own eye rotation, so that saccades from a lateral eye rotation undershoot a central sound (Experiment 1). They discriminated letters faster if they were presented nearer the orbit midline (Experiment 2) and spent less time looking at locations nearer the orbit midline when searching for a nonexistent target in a letter array (Experiment 3). This suggests that visual sensitivity increased nearer the orbit midline, in the same direction as the shift in perceived eye position. This spatial congruence argues for a functional coupling between the cortical eye position signal in the somatosensory cortex and visuospatial attention. more...
- Published
- 2013
- Full Text
- View/download PDF
47. On the Origin of the Eye’s Sensitivity Curves
- Author
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Keith K. Niall
- Subjects
Physics ,Twilight ,Brightness ,genetic structures ,business.industry ,Color vision ,Visual sensitivity ,eye diseases ,medicine.anatomical_structure ,Optics ,medicine ,Human eye ,sense organs ,Sensitivity (control systems) ,Scotopic vision ,business ,Photopic vision - Abstract
The spectral brightness sensitivity function of the ordinary human eye may be considered in terms of the availability of natural sources of illumination. The human eye possesses both a cone system of vision and a rod system of vision. Here it is speculated that their peak brightness sensitivities arose in phylogenetic development, with the cone system being relatively recent in appearance. The older rod system became adapted to the role of low-illumination, or ‘twilight’ vision. The comparative physiology of vision offers support to these conjectures, based on differences in illumination for terrestrial animals and aquatic animals. more...
- Published
- 2017
- Full Text
- View/download PDF
48. Contrast sensitivity, V1 neural activity, and natural vision
- Author
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Michael A. Paradiso and James E. Niemeyer
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Male ,Time Factors ,genetic structures ,Physiology ,media_common.quotation_subject ,Action Potentials ,Adaptation (eye) ,Choice Behavior ,050105 experimental psychology ,Contrast Sensitivity ,03 medical and health sciences ,Neural activity ,0302 clinical medicine ,Saccades ,Contrast (vision) ,Animals ,0501 psychology and cognitive sciences ,Sensitivity (control systems) ,Vision, Ocular ,media_common ,Visual Cortex ,Neurons ,Communication ,business.industry ,General Neuroscience ,05 social sciences ,Eye movement ,Visual sensitivity ,Macaca mulatta ,Saccadic masking ,eye diseases ,Area Under Curve ,Psychology ,business ,Neuroscience ,030217 neurology & neurosurgery ,Photic Stimulation ,Research Article - Abstract
Contrast sensitivity is fundamental to natural visual processing and an important tool for characterizing both visual function and clinical disorders. We simultaneously measured contrast sensitivity and neural contrast response functions and compared measurements in common laboratory conditions with naturalistic conditions. In typical experiments, a subject holds fixation and a stimulus is flashed on, whereas in natural vision, saccades bring stimuli into view. Motivated by our previous V1 findings, we tested the hypothesis that perceptual contrast sensitivity is lower in natural vision and that this effect is associated with corresponding changes in V1 activity. We found that contrast sensitivity and V1 activity are correlated and that the relationship is similar in laboratory and naturalistic paradigms. However, in the more natural situation, contrast sensitivity is reduced up to 25% compared with that in a standard fixation paradigm, particularly at lower spatial frequencies, and this effect correlates with significant reductions in V1 responses. Our data suggest that these reductions in natural vision result from fast adaptation on one fixation that lowers the response on a subsequent fixation. This is the first demonstration of rapid, natural-image adaptation that carries across saccades, a process that appears to constantly influence visual sensitivity in natural vision. NEW & NOTEWORTHY Visual sensitivity and activity in brain area V1 were studied in a paradigm that included saccadic eye movements and natural visual input. V1 responses and contrast sensitivity were significantly reduced compared with results in common laboratory paradigms. The parallel neural and perceptual effects of eye movements and stimulus complexity appear to be due to a form of rapid adaptation that carries across saccades. more...
- Published
- 2016
49. Complex Visual Adaptations in Squid for Specific Tasks in Different Environments
- Author
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Wen-Sung Chung and N. Justin Marshall
- Subjects
0301 basic medicine ,genetic structures ,Physiology ,media_common.quotation_subject ,retinal deformation ,mid-water ,03 medical and health sciences ,Magnetic resonance imagery ,dual-layered inner segment ,Physiology (medical) ,biology.animal ,magnetic resonance imagery ,Biological neural network ,medicine ,Contrast (vision) ,Computer vision ,media_common ,Original Research ,Squid ,Retina ,complex squid retina ,optic lobe ,signal convergence ,biology ,business.industry ,Anatomy ,Visual sensitivity ,eye diseases ,030104 developmental biology ,medicine.anatomical_structure ,%22">Fish ,Inner segment ,Artificial intelligence ,business - Abstract
In common with their major competitors, the fish, squid are fast moving visual predators that live over a great range of depths in the ocean. Both squid and fish show a variety of adaptations with respect to optical properties, receptors and their underlying neural circuits, and these adaptations are often linked to the light conditions of their specific niche. In contrast to the extensive investigations of adaptive strategies in fish, vision in response to the varying quantity and quality of available light, our knowledge of visual adaptations in squid remains sparse. This study therefore undertook a comparative study of visual adaptations and capabilities in a number of squid species collected between 0 and 1,200 m. Histology, magnetic resonance imagery (MRI), and depth distributions were used to compare brains, eyes, and visual capabilities, revealing that the squid eye designs reflect the lifestyle and the versatility of neural architecture in its visual system. Tubular eyes and two types of regional retinal deformation were identified and these eye modifications are strongly associated with specific directional visual tasks. In addition, a combination of conventional and immuno-histology demonstrated a new form of a complex retina possessing two inner segment layers in two mid-water squid species which they rhythmically move across a broad range of depths (50–1,000 m). In contrast to their relatives with the regular single-layered inner segment retina live in the upper mesopelagic layer (50–400 m), the new form of retinal interneuronal layers suggests that the visual sensitivity of these two long distance vertical migrants may increase in response to dimmer environments. more...
- Published
- 2016
50. A comparison of the effects of inferotemporal and striate cortex lesions on the visual behaviour of rhesus monkeys
- Author
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Alan Cowey and Lawrence Weiskrantz
- Subjects
Male ,medicine.medical_specialty ,Visual acuity ,genetic structures ,media_common.quotation_subject ,Basal Ganglia ,050105 experimental psychology ,Discrimination Learning ,03 medical and health sciences ,0302 clinical medicine ,Ophthalmology ,Animals ,Medicine ,Contrast (vision) ,0501 psychology and cognitive sciences ,Visual behaviour ,Discrimination learning ,Vision, Ocular ,media_common ,Cerebral Cortex ,business.industry ,Visually guided ,05 social sciences ,Cognitive neuroscience of visual object recognition ,General Medicine ,Visual sensitivity ,eye diseases ,Form Perception ,Female ,Visual Fields ,Striate cortex ,medicine.symptom ,business ,Neuroscience ,030217 neurology & neurosurgery - Abstract
The effects of bilateral removal of inferotemporal cortex or lateral striate cortex are compared. The former operation impairs visual pattern discrimination learning, without disturbing prompt detection and retrieval of food, visual acuity or visual fields. In contrast, animals in which the macular striate projection area has been removed are significantly superior in tests of visual pattern discrimination learning despite showing impairment of visually guided reaching, visual acuity, and visual fields. The results indicate that the inferotemporal defect is not caused by deficient visual sensitivity or acuity. more...
- Published
- 2016
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