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Foveal

About: Foveal is a research topic. Over the lifetime, 2652 publications have been published within this topic receiving 94120 citations.


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Journal ArticleDOI
TL;DR: Perisaccadic visual localization was measured by presenting brief (250 microseconds), bright (6000 cd/m2), binocular, gaze-point (foveal) probe flashes in an otherwise dark field to normal human subjects instructed to point to them with an unseen hand, finding stable post-saccadic localization was not achieved until about 100-300 msec after completion of a saccade.

22 citations

Journal ArticleDOI
TL;DR: A new test for clinical measurement of crowding in the fovea that is quick and accurate, works well with children and adults, and is expected to work well with dementia patients as well.
Abstract: Crowding is a major limitation of visual perception. Because of crowding, a simple object, like a letter, can only be recognized if clutter is a certain critical spacing away. Crowding is only weakly associated with acuity. The critical spacing of crowding is lowest in the normal fovea, and grows with increasing eccentricity in peripheral vision. Foveal crowding is more prominent in certain patient groups, including those with strabismic amblyopia and apperceptive agnosia. Crowding may lessen with age during childhood as reading speed increases. The range of crowding predicts much of the slowness of reading in children with developmental dyslexia. There is tantalizing evidence suggesting that the critical spacing of crowding indicates neural density (participating neurons per square deg) in the visual cortex. Thus, for basic and applied reasons, it would be very interesting to measure foveal crowding clinically in children and adults with normal and impaired vision, and to track the development of crowding during childhood. While many labs routinely measure peripheral crowding as part of their basic research in visual perception, current tests are not well suited to routine clinical testing because they take too much time, require good fixation, and are mostly not applicable to foveal vision. Here we report a new test for clinical measurement of crowding in the fovea. It is quick and accurate, works well with children and adults, and we expect it to work well with dementia patients as well. The task is to identify a numerical digit, 1-9, using a new “Pelli” font that is identifiable at tiny width (0.02 deg, about 1 minarc, in normal adult fovea). This allows quick measurement of the very small (0.05 deg) critical spacing in the normal adult fovea, as well as with other groups that have higher critical spacing. Preliminary results from healthy adults and children are presented.

22 citations

Journal Article
TL;DR: The findings support the idea that the defect in strabismic amblyopia does not involve a functional abnormality in the fovea distal to the ganglion cell layer.
Abstract: A hand-held stimulator-ophthalmoscope was used to elicit foveal cone electroretinograms (ERGs) from fifteen patients with strabismic amblyopia. The ERGs were in response to a 4 degrees stimulus visualized on the fundus and centred on the fovea throughout testing. Foveal cone ERGs from amblyopic eyes were normal in amplitude and normal in b-wave implicit time. Interocular differences in ERGs in patients with amblyopia were no greater than those in normal subjects. Patients with comparable visual acuity loss due to macular scars or juvenile hereditary macular degeneration had abnormal foveal cone ERGs, while patients with optic atrophy had normal responses. These findings support the idea that the defect in strabismic amblyopia does not involve a functional abnormality in the fovea distal to the ganglion cell layer.

22 citations

Journal ArticleDOI
TL;DR: A fully automated fovea detection algorithm to extract the foveA position in SD-OCT volumes of eyes with exudative maculopathy has cross-vendor functionality, while demonstrating accurate and reliable performance close to typical expert interobserver agreement.
Abstract: In macular spectral domain optical coherence tomography (SD-OCT) volumes, detection of the foveal center is required for accurate and reproducible follow-up studies, structure function correlation, and measurement grid positioning. However, disease can cause severe obscuring or deformation of the fovea, thus presenting a major challenge in automated detection. We propose a fully automated fovea detection algorithm to extract the fovea position in SD-OCT volumes of eyes with exudative maculopathy. The fovea is classified into 3 main appearances to both specify the detection algorithm used and reduce computational complexity. Based on foveal type classification, the fovea position is computed based on retinal nerve fiber layer thickness. Mean absolute distance between system and clinical expert annotated fovea positions from a dataset comprised of 240 SD-OCT volumes was 162.3 µm in cystoid macular edema and 262 µm in nAMD. The presented method has cross-vendor functionality, while demonstrating accurate and reliable performance close to typical expert interobserver agreement. The automatically detected fovea positions may be used as landmarks for intra- and cross-patient registration and to create a joint reference frame for extraction of spatiotemporal features in ?big data.? Furthermore, reliable analyses of retinal thickness, as well as retinal structure function correlation, may be facilitated.

22 citations

Journal ArticleDOI
TL;DR: At high object spatial frequencies peripheral recognition performance could be explained relatively well by the retinal sampling gradient, or equivalently by the cortical magnification factor, together with the effects of the optics of the eye.

22 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023144
2022385
202195
2020119
2019108
201883