Recent Advances in Understanding Peripheral Vision

1986 ◽  
Vol 30 (6) ◽  
pp. 601-603 ◽  
Author(s):  
Mark W. Cannon
Keyword(s):  
Visual Field ◽  
Spatial Pattern ◽  
Peripheral Vision ◽  
Pattern Perception ◽  
Recent Advances ◽  
Entire Visual Field

Recent experiments have revealed a considerable uniformity in the mechanisms mediating spatial pattern perception over the entire visual field.

Pediatric Visual Snow Syndrome (VSS): A Case Series

2019 ◽  
pp. 249-254
Author(s):  
Kenneth J. Ciuffreda ◽  
MH Esther Han ◽  
Barry Tannen
Keyword(s):  
Visual Field ◽  
Case Series ◽  
Therapeutic Interventions ◽  
Visual Condition ◽  
Visual Phenomena ◽  
Entire Visual Field ◽  
The Individual ◽  
Vision Therapy ◽  
Abnormal Visual

Visual snow syndrome (VSS) is a relatively rare, unusual, and disturbing abnormal visual condition. The individual perceives “visual snow” (VS) throughout the entire visual field, as well as other abnormal visual phenomena (e.g., photopsia). Only relatively recently has treatment been proposed (e.g., chromatic filters) in adults with VSS, but rarely in the pediatric VSS population (i.e., medications). In this paper, we present three well-documented cases of VSS in children, including their successful neuro-optometric therapeutic interventions (i.e., chromatic filters and saccadic-based vision therapy)

scholarly journals What do patients with glaucoma see: a novel iPad app to improve glaucoma patient awareness of visual field loss

2020 ◽  
pp. bjophthalmol-2020-317034
Author(s):  
Meghal Gagrani ◽  
Jideofor Ndulue ◽  
David Anderson ◽  
Sachin Kedar ◽  
Vikas Gulati ◽  
...  
Keyword(s):  
Visual Field ◽  
Vision Loss ◽  
Peripheral Vision ◽  
Glaucoma Patient ◽  
Visual Field Loss ◽  
Sensitivity Threshold ◽  
Roc Curve Analysis ◽  
The Mean ◽  
Ipad App ◽  
Field Defects

PurposeGlaucoma patients with peripheral vision loss have in the past subjectively described their field loss as ‘blurred’ or ‘no vision compromise’. We developed an iPad app for patients to self-characterise perception within areas of glaucomatous visual field loss.MethodsTwelve glaucoma patients with visual acuity ≥20/40 in each eye, stable and reliable Humphrey Visual Field (HVF) over 2 years were enrolled. An iPad app (held at 33 cm) allowed subjects to modify ‘blur’ or ‘dimness’ to match their perception of a 2×2 m wall-mounted poster at 1 m distance. Subjects fixated at the centre of the poster (spanning 45° of field from centre). The output was degree of blur/dim: normal, mild and severe noted on the iPad image at the 54 retinal loci tested by the HVF 24-2 and was compared to threshold sensitivity values at these loci. Monocular (Right eye (OD), left eye (OS)) HVF responses were used to calculate an integrated binocular (OU) visual field index (VFI). All three data sets were analysed separately.Results36 HVF and iPad responses from 12 subjects (mean age 71±8.2y) were analysed. The mean VFI was 77% OD, 76% OS, 83% OU. The most common iPad response reported was normal followed by blur. No subject reported dim response. The mean HVF sensitivity threshold was significantly associated with the iPad response at the corresponding retinal loci (For OD, OS and OU, respectively (dB): normal: 23, 25, 27; mild blur: 18, 16, 22; severe blur: 9, 9, 11). On receiver operative characteristic (ROC) curve analysis, the HVF retinal sensitivity cut-off at which subjects reported blur was 23.4 OD, 23 OS and 23.3 OU (dB).ConclusionsGlaucoma subjects self-pictorialised their field defects as blur; never dim or black. Our innovation allows translation of HVF data to quantitatively characterise visual perception in patients with glaucomatous field defects.

Apparent Velocity of Motion Aftereffects in Central and Peripheral Vision

Perception ◽  
1986 ◽  
Vol 15 (5) ◽  
pp. 603-612 ◽  
Author(s):  
Michael J Wright
Keyword(s):  
Visual Field ◽  
Time Course ◽  
Peripheral Vision ◽  
Temporal Frequency ◽  
Motion Aftereffect ◽  
Apparent Velocity ◽  
Real Motion ◽  
Temporal Decay ◽  
Spatial Grain ◽  
Motion Aftereffects

Adapting to a drifting grating (temporal frequency 4 Hz, contrast 0.4) in the periphery gave rise to a motion aftereffect (MAE) when the grating was stopped. A standard unadapted foveal grating was matched to the apparent velocity of the MAE, and the matching velocity was approximately constant regardless of the visual field position and spatial frequency of the adapting grating. On the other hand, when the MAE was measured by nulling with real motion of the test grating, nulling velocity was found to increase with eccentricity. The nulling velocity was constant when scaled to compensate for changes in the spatial ‘grain’ of the visual field. Thus apparent velocity of MAE is constant across the visual field, but requires a greater velocity of real motion to cancel it in the periphery. This confirms that the mechanism underlying MAE is spatially-scaled with eccentricity, but temporally homogeneous. A further indication of temporal homogeneity is that when MAE is tracked, by matching or by nulling, the time course of temporal decay of the aftereffect is similar for central and for peripheral stimuli.

Occipitoparietal alpha-band responses to the graded allocation of top-down spatial attention

2014 ◽  
Vol 112 (6) ◽  
pp. 1307-1316 ◽  
Author(s):  
Isabel Dombrowe ◽  
Claus C. Hilgetag
Keyword(s):  
Visual Field ◽  
Spatial Attention ◽  
Brain Regions ◽  
Alpha Band ◽  
Top Down ◽  
Attentional Resources ◽  
Parietal Lobes ◽  
Visual Spatial ◽  
Entire Visual Field ◽  
Band Activity

The voluntary, top-down allocation of visual spatial attention has been linked to changes in the alpha-band of the electroencephalogram (EEG) signal measured over occipital and parietal lobes. In the present study, we investigated how occipitoparietal alpha-band activity changes when people allocate their attentional resources in a graded fashion across the visual field. We asked participants to either completely shift their attention into one hemifield, to balance their attention equally across the entire visual field, or to attribute more attention to one-half of the visual field than to the other. As expected, we found that alpha-band amplitudes decreased stronger contralaterally than ipsilaterally to the attended side when attention was shifted completely. Alpha-band amplitudes decreased bilaterally when attention was balanced equally across the visual field. However, when participants allocated more attentional resources to one-half of the visual field, this was not reflected in the alpha-band amplitudes, which just decreased bilaterally. We found that the performance of the participants was more strongly reflected in the coherence between frontal and occipitoparietal brain regions. We conclude that low alpha-band amplitudes seem to be necessary for stimulus detection. Furthermore, complete shifts of attention are directly reflected in the lateralization of alpha-band amplitudes. In the present study, a gradual allocation of visual attention across the visual field was only indirectly reflected in the alpha-band activity over occipital and parietal cortexes.

Foveal Attention Modulates Responses to Peripheral Stimuli

2000 ◽  
Vol 83 (4) ◽  
pp. 2443-2452 ◽  
Author(s):  
Simo Vanni ◽  
Kimmo Uutela
Keyword(s):  
Visual Field ◽  
Target Location ◽  
Peripheral Vision ◽  
Human Subjects ◽  
Stimulus Onset ◽  
Visual Object ◽  
Frontal Eye Field ◽  
L1 Norm ◽  
Luminance Stimulus ◽  
The Right

When attending to a visual object, peripheral stimuli must be monitored for appropriate redirection of attention and gaze. Earlier work has revealed precentral and posterior parietal activation when attention has been directed to peripheral vision. We wanted to find out whether similar cortical areas are active when stimuli are presented in nonattended regions of the visual field. The timing and distribution of neuromagnetic responses to a peripheral luminance stimulus were studied in human subjects with and without attention to fixation. Cortical current distribution was analyzed with a minimum L1-norm estimate. Attention enhanced responses 100–160 ms after the stimulus onset in the right precentral cortex, close to the known location of the right frontal eye field. In subjects whose right precentral region was not distinctly active before 160 ms, focused attention commonly enhanced right inferior parietal responses between 180 and 240 ms, whereas in the subjects with clear earlier precentral response no parietal enhancement was detected. In control studies both attended and nonattended stimuli in the peripheral visual field evoked the right precentral response, whereas during auditory attention the visual stimuli failed to evoke such response. These results show that during focused visual attention the right precentral cortex is sensitive to stimuli in all parts of the visual field. A rapid response suggests bypassing of elaborate analysis of stimulus features, possibly to encode target location for a saccade or redirection of attention. In addition, load for frontal and parietal nodi of the attentional network seem to vary between individuals.

scholarly journals A P300 brain-computer interface with a reduced visual field

2020 ◽  
Author(s):  
Luiza Kirasirova ◽  
Vladimir Bulanov ◽  
Alexei Ossadtchi ◽  
Alexander Kolsanov ◽  
Vasily Pyatin ◽  
...  
Keyword(s):  
Visual Field ◽  
Visual Processing ◽  
Peripheral Vision ◽  
Brain Computer Interface ◽  
Basic Research ◽  
Computer Interface ◽  
Eye Tracker ◽  
Central Visual Field ◽  
P300 Speller ◽  
User Fatigue

AbstractA P300 brain-computer interface (BCI) is a paradigm, where text characters are decoded from visual evoked potentials (VEPs). In a popular implementation, called P300 speller, a subject looks at a display where characters are flashing and selects one character by attending to it. The selection is recognized by the strongest VEP. The speller performs well when cortical responses to target and non-target stimuli are sufficiently different. Although many strategies have been proposed for improving the spelling, a relatively simple one received insufficient attention in the literature: reduction of the visual field to diminish the contribution from non-target stimuli. Previously, this idea was implemented in a single-stimulus switch that issued an urgent command. To tackle this approach further, we ran a pilot experiment where ten subjects first operated a traditional P300 speller and then wore a binocular aperture that confined their sight to the central visual field. Visual field restriction resulted in a reduction of non-target responses in all subjects. Moreover, in four subjects, target-related VEPs became more distinct. We suggest that this approach could speed up BCI operations and reduce user fatigue. Additionally, instead of wearing an aperture, non-targets could be removed algorithmically or with a hybrid interface that utilizes an eye tracker. We further discuss how a P300 speller could be improved by taking advantage of the different physiological properties of the central and peripheral vision. Finally, we suggest that the proposed experimental approach could be used in basic research on the mechanisms of visual processing.

scholarly journals Role of the Dorsal Posterior Parietal Cortex in the Accurate Perception of Object Magnitude in Peripheral Vision

i-Perception ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 204166952110584
Author(s):  
Tristan Jurkiewicz ◽  
Romeo Salemme ◽  
Caroline Froment ◽  
Laure Pisella
Keyword(s):  
Visual Field ◽  
Posterior Parietal Cortex ◽  
Peripheral Vision ◽  
Visual Fields ◽  
Size Perception ◽  
Control Group ◽  
Optic Ataxia ◽  
Actual Object ◽  
Pointing Errors ◽  
Accurate Perception

Following superior parietal lobule and intraparietal sulcus (SPL-IPS) damage, optic ataxia patients underestimate the distance of objects in the ataxic visual field such that they produce hypometric pointing errors. The metrics of these pointing errors relative to visual target eccentricity fit the cortical magnification of central vision. The SPL-IPS would therefore implement an active “peripheral magnification” to match the real metrics of the environment for accurate action. We further hypothesized that this active compensation of the central magnification by the SPL-IPS contributes to actual object’ size perception in peripheral vision. Three optic ataxia patients and 10 age-matched controls were assessed in comparing the thickness of two rectangles flashed simultaneously, one in central and another in peripheral vision. The bilateral optic ataxia patient exhibited exaggerated underestimation bias and uncertainty compared to the control group in both visual fields. The two unilateral optic ataxia patients exhibited a pathological asymmetry between visual fields: size perception performance was affected in their contralesional peripheral visual field compared to their healthy side. These results demonstrate that the SPL-IPS contributes to accurate size perception in peripheral vision.

scholarly journals Brightness Perception Throughout the Entire Visual Field

2015 ◽  
Vol 99 (5) ◽  
pp. 258-262 ◽  
Author(s):  
Tasuku Watanuki ◽  
Hiroshi Takahashi ◽  
Takashi Irikura
Keyword(s):  
Visual Field ◽  
Brightness Perception ◽  
Entire Visual Field

Effect of Practice on Expansion of Peripheral Vision

1973 ◽  
Vol 37 (3) ◽  
pp. 720-722 ◽  
Author(s):  
A. Louise Sailor
Keyword(s):  
Visual Field ◽  
Analysis Of Variance ◽  
Stimulus Object ◽  
Peripheral Vision ◽  
Visual Fields ◽  
Speed Reading ◽  
And Control ◽  
Experimental Partner

This study was designed to test the effect of practice on the expansion of peripheral vision. 24 college speed reading students were tested for a measure of peripheral vision with a Lafayette Color Perimeter. Half of the Ss practiced detection of a white stimulus object for a period of 6 wk. Ss serving as controls assisted by moving the carrier into the visual field of an experimental partner. Analysis of variance showed significant increase in visual fields for all Ss, experimental and control. Attention factors and equipment used in the speed reading classes appear to account for these results.

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