Macular drusen and the sensitivity of the central visual field

1994 ◽  
Vol 88 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Edoardo Midena ◽  
Tatiana Segato ◽  
Maria Chiara Blarzino ◽  
Claudia Degli Angeli
Keyword(s):  
Visual Field ◽  
Central Visual Field ◽  
Macular Drusen

scholarly journals Central Visual Field Defects in Patients with Distinct Glaucomatous Optic Disc Phenotypes

2021 ◽  
Vol 223 ◽  
pp. 229-240
Author(s):  
Eren Ekici ◽  
Sasan Moghimi ◽  
Huiyuan Hou ◽  
James Proudfoot ◽  
Linda M. Zangwill ◽  
...  
Keyword(s):  
Visual Field ◽  
Optic Disc ◽  
Visual Field Defects ◽  
Central Visual Field ◽  
Field Defects

A role for the corpus callosum in visual area V4 of the macaque

1993 ◽  
Vol 10 (1) ◽  
pp. 159-171 ◽  
Author(s):  
Robert Desimone ◽  
Jeffrey Moran ◽  
Stanley J. Schein ◽  
Mortimer Mishkin
Keyword(s):  
Visual Field ◽  
Corpus Callosum ◽  
Anterior Commissure ◽  
Color Constancy ◽  
Receptive Fields ◽  
Optic Tract ◽  
Complete Suppression ◽  
Central Visual Field ◽  
Field Representation ◽  
Area V4

AbstractThe classically defined receptive fields of V4 cells are confined almost entirely to the contralateral visual field. However, these receptive fields are often surrounded by large, silent suppressive regions, and stimulating the surrounds can cause a complete suppression of response to a simultaneously presented stimulus within the receptive field. We investigated whether the suppressive surrounds might extend across the midline into the ipsilateral visual field and, if so, whether the surrounds were dependent on the corpus callosum, which has a widespread distribution in V4. We found that the surrounds of more than half of the cells tested in the central visual field representation of V4 crossed into the ipsilateral visual field, with some extending up to at least 16 deg from the vertical meridian. Much of this suppression from the ipsilateral field was mediated by the corpus callosum, as section of the callosum dramatically reduced both the strength and extent of the surrounds. There remained, however, some residual suppression that was not further reduced by addition of an anterior commissure lesion. Because the residual ipsilateral suppression was similar in magnitude and extent to that found following section of the optic tract contralateral to the V4 recording, we concluded that it was retinal in origin. Using the same techniques employed in V4, we also mapped the ipsilateral extent of surrounds in the foveal representation of VI in an intact monkey. Results were very similar to those in V4 following commissural or contralateral tract sections. The findings suggest that V4 is a central site for long-range interactions both within and across the two visual hemifields. Taken with previous work, the results are consistent with the notion that the large suppressive surrounds of V4 neurons contribute to the neural mechanisms of color constancy and figure-ground separation.

Visual Field Damage and Progression in Glaucomatous Myopic Eyes

2007 ◽  
Vol 17 (4) ◽  
pp. 534-537 ◽  
Author(s):  
A. Perdicchi ◽  
M. Iester ◽  
G. Scuderi ◽  
S. Amodeo ◽  
E.M. Medori ◽  
...  
Keyword(s):  
Visual Field ◽  
Open Angle Glaucoma ◽  
Linear Regression Analysis ◽  
Visual Fields ◽  
Light Sensitivity ◽  
Progressive Increase ◽  
Central Visual Field ◽  
Trend Function ◽  
Visual Field Damage ◽  
Loss Variance

Purpose To make a visual field retrospective analysis on a group of patients with primary open angle glaucoma (POAG) and to evaluate whether different refractive errors could have different progression of the 30° central sensitivity. Methods A total of 110 patients with POAG (52 men and 58 women) were included in the study. All the patients were divided into four subgroups based on the refractive error. The visual field of all the included patients was assessed by an Octopus 30° central visual field every 6 months, for a total of 837 visual fields examined. The resulting data were analyzed by PERIDATA for Windows 1.7 TREND function. Mean defect (MD) and loss variance (LV) were considered for the analysis. Results At the first examination, 82% of eyes showed a global decrease of differential light sensitivity (MD >2 dB) and in 67% the distribution of the defect was nonhomogeneous (LV >6 dB). The analysis of variance for subgroups showed a more significant decrease of MD in highly myopic patients. A linear regression analysis highlighted a statistically significant change in time of MD in 36% and of LV in 34% of the eyes studied. Highly myopic patients had the highest (p<0.01) percentage of change of MD and LV (46% and 42%, respectively). Among the four subgroups, there was no difference in progression of MD decrease in time. Conclusions These results showed that after 5 years of glaucoma, the visual field was altered in most of the eyes examined (82%) and that in 67% of cases, its defect was nonhomogeneous and worsened with the increase of myopia. The regression linear analysis of visual field changes in time showed a progressive increase of MD and LV in approximately one third of all the eyes examined.

Agreement between Compass Fundus Perimeter New Grid and 10-2 Testing Protocols for Detecting Central Visual Field Defects

2021 ◽  
Author(s):  
Nevin W. El-Nimri ◽  
Rafaella C. Penteado ◽  
Christopher Bowd ◽  
James A. Proudfoot ◽  
Huiyuan Hou ◽  
...  
Keyword(s):  
Visual Field ◽  
Visual Field Defects ◽  
Central Visual Field ◽  
Testing Protocols ◽  
Field Defects

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.

The magnitude of the central visual field could be detected by active middle-late processing of ERPs

2016 ◽  
Vol 1650 ◽  
pp. 41-50
Author(s):  
Maojuan Li ◽  
Xiaoqin Liu ◽  
Qianqian Li ◽  
Mengmeng Ji ◽  
Wenwen Huang ◽  
...  
Keyword(s):  
Visual Field ◽  
Central Visual Field
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