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Showing papers on "Foveal published in 2015"


Journal ArticleDOI
TL;DR: Optical coherence tomography angiography provides a noninvasive method to visualize and measure the superficial and deep plexus FAZ in a normal population, which can vary in size and shape, with the FAZ area significantly larger in the deep compared with the superficial plexi.
Abstract: Purpose:To analyze the foveal avascular zone (FAZ) in normal eyes using optical coherence tomography angiography.Methods:Prospective noncomparative case series. The parafoveal region of 70 eyes from 67 healthy subjects was imaged using optical coherence tomography angiography to visualize the superf

290 citations


Journal ArticleDOI
TL;DR: The findings show that the human visual system can effectively use peripheral and foveal information about object features and that visual perception does not simply correspond to disconnected snapshots during each fixation.
Abstract: Due to the inhomogenous visual representation across the visual field, humans use peripheral vision to select objects of interest and foveate them by saccadic eye movements for further scrutiny. Thus, there is usually peripheral information available before and foveal information after a saccade. In this study we investigated the integration of information across saccades. We measured reliabilities--i.e., the inverse of variance-separately in a presaccadic peripheral and a postsaccadic foveal orientation--discrimination task. From this, we predicted trans-saccadic performance and compared it to observed values. We show that the integration of incongruent peripheral and foveal information is biased according to their relative reliabilities and that the reliability of the trans-saccadic information equals the sum of the peripheral and foveal reliabilities. Both results are consistent with and indistinguishable from statistically optimal integration according to the maximum-likelihood principle. Additionally, we tracked the gathering of information around the time of the saccade with high temporal precision by using a reverse correlation method. Information gathering starts to decline between 100 and 50 ms before saccade onset and recovers immediately after saccade offset. Altogether, these findings show that the human visual system can effectively use peripheral and foveal information about object features and that visual perception does not simply correspond to disconnected snapshots during each fixation.

103 citations


Journal ArticleDOI
TL;DR: Although the underlying pathomechanisms for differential GA progression remain unknown, local factors may be operative that protect the foveal retina-retinal pigment epithelial complex and Quantification of directional spread characteristics and modeling may be useful in the design of interventional clinical trials aiming to prolong foveale survival in eyes with GA.

98 citations


Journal ArticleDOI
15 Jun 2015-PLOS ONE
TL;DR: In this article, the authors used Spectralis segmentation software to obtain thickness of eight individual retinal layers at 0°, 2° and 5° eccentricities nasal and temporal to foveal centre.
Abstract: PURPOSE: To investigate repeatability and reproducibility of thickness of eight individual retinal layers at axial and lateral foveal locations, as well as foveal width, measured from Spectralis spectral domain optical coherence tomography (SD-OCT) scans using newly available retinal layer segmentation software. METHODS: High-resolution SD-OCT scans were acquired for 40 eyes of 40 young healthy volunteers. Two scans were obtained in a single visit for each participant. Using new Spectralis segmentation software, two investigators independently obtained thickness of each of eight individual retinal layers at 0°, 2° and 5° eccentricities nasal and temporal to foveal centre, as well as foveal width measurements. Bland-Altman Coefficient of Repeatability (CoR) was calculated for inter-investigator and inter-scan agreement of all retinal measurements. Spearman's ρ indicated correlation of manually located central retinal thickness (RT0) with automated minimum foveal thickness (MFT) measurements. In addition, we investigated nasal-temporal symmetry of individual retinal layer thickness within the foveal pit. RESULTS: Inter-scan CoR values ranged from 3.1μm for axial retinal nerve fibre layer thickness to 15.0μm for the ganglion cell layer at 5° eccentricity. Mean foveal width was 2550μm ± 322μm with a CoR of 13μm for inter-investigator and 40μm for inter-scan agreement. Correlation of RT0 and MFT was very good (ρ = 0.97, P 0.05); however this symmetry could not be found at 5° eccentricity. CONCLUSIONS: We demonstrate excellent repeatability and reproducibility of each of eight individual retinal layer thickness measurements within the fovea as well as foveal width using Spectralis SD-OCT segmentation software in a young, healthy cohort. Thickness of all individual retinal layers were symmetrical at 2°, but not at 5° eccentricity away from the fovea.

91 citations


Journal ArticleDOI
TL;DR: It is found that humans perform best when an oriented target is visible both before (peripherally) and after a saccade (foveally), suggesting that humans integrate the two views.
Abstract: We perceive a stable environment despite the fact that visual information is essentially acquired in a sequence of snapshots separated by saccadic eye movements. The resolution of these snapshots varies-high in the fovea and lower in the periphery-and thus the formation of a stable percept presumably relies on the fusion of information acquired at different resolutions. To test if, and to what extent, foveal and peripheral information are integrated, we examined human orientation-discrimination performance across saccadic eye movements. We found that humans perform best when an oriented target is visible both before (peripherally) and after a saccade (foveally), suggesting that humans integrate the two views. Integration relied on eye movements, as we found no evidence of integration when the target was artificially moved during stationary viewing. Perturbation analysis revealed that humans combine the two views using a weighted sum, with weights assigned based on the relative precision of foveal and peripheral representations, as predicted by ideal observer models. However, our subjects displayed a systematic overweighting of the fovea, relative to the ideal observer, indicating that human integration across saccades is slightly suboptimal.

79 citations


Journal ArticleDOI
TL;DR: The projection from the amblyopic eye was found to have a normal cortical magnification factor, enlarged population receptive field sizes, and topographic disorganization in all early visual areas, consistent with an explanation of amblyopia as an immature system with a normal complement of cells whose spatial resolution is reduced and whose topographical map is disordered.
Abstract: The neural basis of amblyopia is a matter of debate. The following possibilities have been suggested: loss of foveal cells, reduced cortical magnification, loss of spatial resolution of foveal cells, and topographical disarray in the cellular map. To resolve this we undertook a population receptive field (pRF) functional magnetic resonance imaging analysis in the central field in humans with moderate-to-severe amblyopia. We measured the relationship between averaged pRF size and retinal eccentricity in retinotopic visual areas. Results showed that cortical magnification is normal in the foveal field of strabismic amblyopes. However, the pRF sizes are enlarged for the amblyopic eye. We speculate that the pRF enlargement reflects loss of cellular resolution or an increased cellular positional disarray within the representation of the amblyopic eye. SIGNIFICANCE STATEMENT The neural basis of amblyopia, a visual deficit affecting 3% of the human population, remains a matter of debate. We undertook the first population receptive field functional magnetic resonance imaging analysis in participants with amblyopia and compared the projections from the amblyopic and fellow normal eye in the visual cortex. The projection from the amblyopic eye was found to have a normal cortical magnification factor, enlarged population receptive field sizes, and topographic disorganization in all early visual areas. This is consistent with an explanation of amblyopia as an immature system with a normal complement of cells whose spatial resolution is reduced and whose topographical map is disordered. This bears upon a number of competing theories for the psychophysical defect and affects future treatment therapies.

56 citations


Journal ArticleDOI
TL;DR: The visual system configuration of emberizid sparrows (single fovea, wide binocular field, high eye movement amplitude) can meet multiple sensory demands for foraging and predator detection purposes.
Abstract: Avian species vary in their visual system configuration, but previous studies have often compared single visual traits between two to three distantly related species. However, birds use different visual dimensions that cannot be maximized simultaneously to meet different perceptual demands, potentially leading to trade-offs between visual traits. We studied the degree of inter-specific variation in multiple visual traits related to foraging and anti-predator behaviors in nine species of closely related emberizid sparrows, controlling for phylogenetic effects. Emberizid sparrows maximize binocular vision, even seeing their bill tips in some eye positions, which may enhance the detection of prey and facilitate food handling. Sparrows have a single retinal center of acute vision (i.e. fovea) projecting fronto-laterally (but not into the binocular field). The foveal projection close to the edge of the binocular field may shorten the time to gather and process both monocular and binocular visual information from the foraging substrate. Contrary to previous work, we found that species with larger visual fields had higher visual acuity, which may compensate for larger blind spots (i.e. pectens) above the center of acute vision, enhancing predator detection. Finally, species with a steeper change in ganglion cell density across the retina had higher eye movement amplitude, probably due to a more pronounced reduction in visual resolution away from the fovea, which would need to be moved around more frequently. The visual configuration of emberizid passive prey foragers is substantially different from that of previously studied avian groups (e.g. sit-and-wait and tactile foragers).

46 citations


Journal ArticleDOI
26 Feb 2015-Cortex
TL;DR: The results suggest that the sequential part-based processing strategy that promotes the length effect in the reading of these patients also allows them to discriminate between faces on the basis of feature identity, but processing of second-order configuration information is most compromised due to their left pFG lesion.

44 citations


Journal ArticleDOI
TL;DR: Examination of the relative roles of central and peripheral vision when performing a dynamic forced-choice task found that high levels of blur did not prevent better-than-chance performance by skilled players when peripheral information was blurred, but they did affect response accuracy when impairing central vision.
Abstract: The main purpose of this study was to examine the relative roles of central and peripheral vision when performing a dynamic forced-choice task. We did so by using a gaze-contingent display with different levels of blur in an effort to (a) test the limit of visual resolution necessary for information pick-up in each of these sectors of the visual field and, as a result, to (b) develop a more natural means of gaze-contingent display using a blurred central or peripheral visual field. The expert advantage seen in usual whole field visual presentation persists despite surprisingly high levels of impairment to central or peripheral vision. Consistent with the well-established central/peripheral differences in sensitivity to spatial frequency, high levels of blur did not prevent better-than-chance performance by skilled players when peripheral information was blurred, but they did affect response accuracy when impairing central vision. Blur was found to always alter the pattern of eye movements before it decreased task performance. The evidence accumulated across the 4 experiments provides new insights into several key questions surrounding the role that different sectors of the visual field play in expertise in dynamic, time-constrained tasks.

43 citations


Journal ArticleDOI
TL;DR: It is shown, for the first time, that robust contour interactions exist in the fovea for much larger target-flanker spacing than reported previously: participants overcome crowded conditions for long presentations times but exhibit contour interaction effects for short presentation times.
Abstract: Visual crowding, as context modulation, reduce the ability to recognize objects in clutter, sets a fundamental limit on visual perception and object recognition. It's considered that crowding does not exist in the fovea and extensive efforts explored crowding in the periphery revealed various models that consider several aspects of spatial processing. Studies showed that spatial and temporal crowding are correlated, suggesting a tradeoff between spatial and temporal processing of crowding. We hypothesized that limiting stimulus availability should decrease object recognition in clutter. Here we show, for the first time, that robust contour interactions exist in the fovea for much larger target-flanker spacing than reported previously: participants overcome crowded conditions for long presentations times but exhibit contour interaction effects for short presentation times. Thus, by enabling enough processing time in the fovea, contour interactions can be overcome, enabling object recognition. Our results suggest that contemporary models of context modulation should include both time and spatial processing.

42 citations


Journal ArticleDOI
TL;DR: The spectrum of ocular structure and visual function inAlbinism is broad, suggesting a possible diagnosis of albinism in a patient with an even more normal clinical presentation.
Abstract: Purpose A hallmark of albinism is foveal hypoplasia. However, literature suggests variable foveal development. This study evaluates the association between ocular phenotype and foveal morphology to demonstrate the broad structural and functional spectrum. Methods Best-corrected visual acuity (BCVA), nystagmus, angle kappa, stereoacuity, iris transillumination, macular melanin presence, foveal avascular zone, and annular reflex were recorded in 14 patients with albinism. Spectral-domain optical coherence tomography provided macular images. Results The clinical phenotype was broad, with BCVA varying from 20/20 to 20/100. Better BCVA was associated with a preserved foveal avascular zone, annular macular reflex, stereoacuity, and macular melanin. Imaging demonstrated a continuum of foveal development correlating with BCVA. Individuals with a rudimentary pit had normal inner and outer segment lengthening and better BCVA. Conclusions The spectrum of ocular structure and visual function in albinism is broad, suggesting a possible diagnosis of albinism in a patient with an even more normal clinical presentation.

Journal ArticleDOI
TL;DR: It is found that when the visual stimulus was attended, background connectivity between V1 and the left frontal eye fields (FEF), left intraparietal sulcus (IPS), and right IPS varied strongly across different eccentricity sectors in V1 so that foveal sectors were more strongly connected than peripheral sectors.
Abstract: Attention facilitates the processing of task-relevant visual information and suppresses interference from task-irrelevant information. Modulations of neural activity in visual cortex depend on attention, and likely result from signals originating in fronto-parietal and cingulo-opercular regions of cortex. Here, we tested the hypothesis that attentional facilitation of visual processing is accomplished in part by changes in how brain networks involved in attentional control interact with sectors of V1 that represent different retinal eccentricities. We measured the strength of background connectivity between fronto-parietal and cingulo-opercular regions with different eccentricity sectors in V1 using functional MRI data that were collected while participants performed tasks involving attention to either a centrally presented visual stimulus or a simultaneously presented auditory stimulus. We found that when the visual stimulus was attended, background connectivity between V1 and the left frontal eye fields (FEF), left intraparietal sulcus (IPS), and right IPS varied strongly across different eccentricity sectors in V1 so that foveal sectors were more strongly connected than peripheral sectors. This retinotopic gradient was weaker when the visual stimulus was ignored, indicating that it was driven by attentional effects. Greater task-driven differences between foveal and peripheral sectors in background connectivity to these regions were associated with better performance on the visual task and faster response times on correct trials. These findings are consistent with the notion that attention drives the configuration of task-specific functional pathways that enable the prioritized processing of task-relevant visual information, and show that the prioritization of visual information by attentional processes may be encoded in the retinotopic gradient of connectivty between V1 and fronto-parietal regions.

Journal ArticleDOI
TL;DR: It is suggested that saccades are accompanied by a prediction of their perceptual consequences (i.e., the foveation of the target object) which should be biased toward previously associated foveal input, enabling predictions about the perceptual consequences of saccadic eye movements.
Abstract: Human vision is characterized by a consistent pattern of saccadic eye movements. With each saccade, internal object representations change their retinal position and spatial resolution. This raises the question as to how peripheral perception is affected by imminent saccadic eye movements. Here, we suggest that saccades are accompanied by a predictionoftheirperceptualconsequences(i.e.,thefoveationofthetargetobject).Accordingly,peripheralperception should be biased toward previously associated foveal input. In this study, we first exposed participants to an altered visualstimulationwhereoneobjectsystematicallychangeditsshapeduringsaccades.Subsequently,participantshad to judge the shape of briefly presented peripheral saccade targets. The results showed that targets were perceived as less curved for objects that previously changed from more circular in the periphery to more triangular in the fovea. Similarly,shapeswereperceivedasmorecurvedforobjectsthatpreviouslychangedfromtriangulartocircular.Thus, peripheral perception seems to depend not solely on the current input but also on memorized experiences, enabling predictions about the perceptual consequences of saccadic eye movements.

Journal ArticleDOI
TL;DR: In eyes with idiopathic ERM and decreased vision due to abnormally thick IRL in the foveal center, postoperative visual outcomes correlated well with preoperative CIRLT and postoperative restoration of IRL configuration after ERM peeling.
Abstract: Purpose To investigate foveal inner retinal layer (IRL) restoration and its relationship with functional visual outcomes after membrane peeling in eyes with idiopathic epiretinal membrane (ERM) with foveal central thick IRL. Methods Consecutive eyes (n = 57) with a thick foveal IRL that underwent 25-gauge vitrectomy for ERM treatment were included. Complete ophthalmic and spectral domain optical coherence tomography examinations were performed before and 1 year after surgery. Results Before surgery, mean best-corrected visual acuity (BCVA) was 20/48 (logMAR, 0.38); central foveal thickness, 515.0 ± 90.9 μm; and central IRL thickness (CIRLT) at the fovea, 167.7 ± 80.1 μm. One year after ERM peeling, mean BCVA improved to 20/30 (logMAR, 0.18), central foveal thickness to 404.1 ± 96.4 μm, and CIRLT to 76.8 ± 68.0 μm. In multivariate analysis, initial BCVA and CIRLT at baseline correlated well with final BCVA and BCVA improvement at 12 months. In comparison with Group B eyes (persistently thick foveal IRL at 12 months), Group A eyes (restored foveal IRL at 12 months) had thinner CIRLT at baseline and showed a significant post-surgical improvement in BCVA and metamorphopsia. Conclusion In eyes with idiopathic ERM and decreased vision due to abnormally thick IRL in the foveal center, postoperative visual outcomes correlated well with preoperative CIRLT and postoperative restoration of IRL configuration after ERM peeling.

Journal ArticleDOI
TL;DR: Foveal thinning highly correlates with motor impairment and also disease duration, and quantifying capillary and neuronal remodeling could serve as biological markers.
Abstract: Inner foveal thinning and intracellular alpha-synuclein were demonstrated in the retina in Parkinson disease. While pathognomonic alpha-synuclein is associated with embryonic dopaminergic (DA) neurons, postmortem studies in the nervous system and retina show prominent effect also in non-DA neurons. We evaluated foveal capillaries and foveal thickness in 23 Parkinson disease subjects and 13 healthy controls using retinal fluorescein angiography and optical coherence tomography. The size of the foveal avascular zone inversely correlates with foveal thinning. Foveal thinning highly correlates with motor impairment and also disease duration. Quantifying capillary and neuronal remodeling could serve as biological markers.

Journal ArticleDOI
TL;DR: This paper used GlassesOff's application for iDevices to train foveal vision of young participants at reading distance based on contrast detection tasks under different spatial and temporal constraints using Gabor patches.
Abstract: Studies show that manipulating certain training features in perceptual learning determines the specificity of the improvement. The improvement in abnormal visual processing following training and its generalization to visual acuity, as measured on static clinical charts, can be explained by improved sensitivity or processing speed. Crowding, the inability to recognize objects in a clutter, fundamentally limits conscious visual perception. Although it was largely considered absent in the fovea, earlier studies report foveal crowding upon very brief exposures or following spatial manipulations. Here we used GlassesOff's application for iDevices to train foveal vision of young participants. The training was performed at reading distance based on contrast detection tasks under different spatial and temporal constraints using Gabor patches aimed at testing improvement of processing speed. We found several significant improvements in spatio-temporal visual functions including near and also non-trained far distances. A remarkable transfer to visual acuity measured under crowded conditions resulted in reduced processing time of 81 ms, in order to achieve 6/6 acuity. Despite a subtle change in contrast sensitivity, a robust increase in processing speed was found. Thus, enhanced processing speed may lead to overcoming foveal crowding and might be the enabling factor for generalization to other visual functions.

Journal ArticleDOI
TL;DR: In this paper, the authors explore interactions of local context and global structure in the long-term learning and retrieval of invariant display properties, showing that invariant spatial display properties can be acquired based on scarce, para-/foveal information, while their effective retrieval for search guidance requires the availability (even if brief) of peripheral information.
Abstract: Our visual brain is remarkable in extracting invariant properties from the noisy environment, guiding selection of where to look and what to identify. However, how the brain achieves this is still poorly understood. Here we explore interactions of local context and global structure in the long-term learning and retrieval of invariant display properties. Participants searched for a target among distractors, without knowing that some “old” configurations were presented repeatedly (randomly inserted among “new” configurations). We simulated tunnel vision, limiting the visible region around fixation. Robust facilitation of performance for old versus new contexts was observed when the visible region was large but not when it was small. However, once the display was made fully visible during the subsequent transfer phase, facilitation did become manifest. Furthermore, when participants were given a brief preview of the total display layout prior to tunnel view search with 2 items visible, facilitation was already obtained during the learning phase. The eye movement results revealed contextual facilitation to be coupled with changes of saccadic planning, characterized by slightly extended gaze durations but a reduced number of fixations and shortened scan paths for old displays. Taken together, our findings show that invariant spatial display properties can be acquired based on scarce, para-/foveal information, while their effective retrieval for search guidance requires the availability (even if brief) of a certain extent of peripheral information.

Journal ArticleDOI
TL;DR: To test directly whether foveating objects is necessary for ensemble perception, observers' sensitivity to average facial emotion in the absence of foveal input was measured and showed no difference in accuracy between the occluded and non-occluded conditions.
Abstract: The visual system extracts average features from groups of objects (Ariely, 2001; Dakin & Watt, 1997; Watamaniuk & Sekuler, 1992), including high-level stimuli such as faces (Haberman & Whitney, 2007, 2009). This phenomenon, known as ensemble perception, implies a covert process, which would not require fixation of individual stimulus elements. However, some evidence suggests that ensemble perception may instead be a process of averaging foveal input across sequential fixations (Ji, Chen, & Fu, 2013; Jung, Bulthoff, Thornton, Lee, & Armann, 2013). To test directly whether foveating objects is necessary, we measured observers' sensitivity to average facial emotion in the absence of foveal input. Subjects viewed arrays of 24 faces, either in the presence or absence of a gaze-contingent foveal occluder, and adjusted a test face to match the average expression of the array. We found no difference in accuracy between the occluded and non-occluded conditions, demonstrating that foveal input is not required for ensemble perception. Unsurprisingly, without foveal input, subjects spent significantly less time directly fixating faces, but this did not translate into any difference in sensitivity to ensemble expression. Next, we varied the number of faces visible from the set to test whether subjects average multiple faces from the crowd. In both conditions, subjects' performance improved as more faces were presented, indicating that subjects integrated information from multiple faces in the display regardless of whether they had access to foveal information. Our results demonstrate that ensemble perception can be a covert process, not requiring access to direct foveal information.

Journal ArticleDOI
TL;DR: To characterize typical microanatomical alterations of immaturity in the fovea, that remain into childhood, after extremely preterm birth before 27 weeks gestational age (GA) and to suggest a clinical methodological evaluation tool.

Journal ArticleDOI
TL;DR: Results from probe-VEPs indicate that enhanced processing of the foveal target rather than suppression of the peripheral flankers supports interference control, implying that predictability alters interference control by a reconfiguration of stimulus processing.

Journal ArticleDOI
TL;DR: Using radial scans, 71% of eyes demonstrated a foveal lucency at 1 month, whose size correlated with visual recovery following macular hole surgery, and preoperative basal hole diameter was predictive of foveAL lucency development and size.

Journal ArticleDOI
TL;DR: Besides traction retinal detachment, vision loss in IP can occur with abnormalities of the inner foveal structure seen on spectral-domain optical coherence tomography, consistent with prior descriptions of fveal hypoplasia.
Abstract: Importance This report presents evidence from spectral-domain optical coherence tomography and fluorescein angiography of inner foveal structural abnormalities associated with vision loss in incontinentia pigmenti (IP). Observations Two children had reduced visual behavior in association with abnormalities of the inner foveal layers on spectral-domain optical coherence tomography. Fluorescein angiography showed filling defects in retinal and choroidal circulations and irregularities of the foveal avascular zones. The foveal to parafoveal ratios were greater than 0.57 in 6 eyes of 3 patients who had extraretinal neovascularization and/or peripheral avascular retina on fluorescein angiography and were treated with laser. Of these, 3 eyes of 2 patients had irregularities in foveal avascular zones and poor vision. Conclusions and Relevance Besides traction retinal detachment, vision loss in IP can occur with abnormalities of the inner foveal structure seen on spectral-domain optical coherence tomography, consistent with prior descriptions of foveal hypoplasia. The evolution of abnormalities in the neural and vascular retina suggests a vascular cause of the foveal structural changes. More study is needed to determine any potential benefit of the foveal to parafoveal ratio in children with IP. Even with marked foveal structural abnormalities, vision can be preserved in some patients with IP with vigilant surveillance in the early years of life.

Journal ArticleDOI
TL;DR: Polarization-sensitive OCT can better allow correct grading of the fovea in relation to BCVA and identify foveal sparing than other imaging modalities, and should be considered in diagnostic and therapeutic evaluations.
Abstract: PURPOSE To compare current imaging methods with respect to their ability to detect the condition of the fovea in patients with geographic atrophy (GA). METHODS The retinas of 176 eyes with GA were imaged using two spectral-domain optical coherence tomography (SD-OCT) systems, Cirrus HD-OCT and Spectralis HRA+OCT, and fundus autofluorescence (FAF) and infrared imaging (IR) was used in the scanning laser ophthalmoscope (SLO) mode. Polarization-sensitive OCT (PS-OCT), which selectively visualizes the RPE in addition to SD-OCT features, was used to image 95 eyes. Geographic atrophy lesions were categorized as fovea spared, involved, or not quantifiable (grades 0, 1, and 2). Morphologic gradings were subsequently correlated with best-corrected visual acuity (BCVA) measurements to independently identify the corresponding functional condition of the fovea. Cohen's κ statistics with a bootstrap method was applied to compare retinal imaging methods. RESULTS In PS-OCT, 84% of eyes with BCVA greater than or equal to 20/40 were detected, whereas in conventional retinal imaging the rate ranged from 27% in FAF to 45% in the SD-OCT segment. Cohen's κ statistics revealed significant differences between the gradings of PS-OCT and conventional imaging with κ = 0.488 and a global Hotelling's T2 statistic of 17.9 with a P value of P = 0.003. Statistical tests revealed no statistically significant differences between the conventional retinal imaging modalities. CONCLUSIONS Polarization-sensitive OCT can better allow correct grading of the fovea in relation to BCVA and identify foveal sparing than other imaging modalities. The differences in imaging precision should be considered in diagnostic and therapeutic evaluations.

Journal ArticleDOI
TL;DR: Data suggest that V6A contains multiple representations of spatial information for reaching, consistent with a role of this area in forming cross-reference frame representations to be used by premotor cortex.
Abstract: During foveal reaching, the activity of neurons in the macaque medial posterior parietal area V6A is modulated by both gaze and arm direction. In the present work, we dissociated the position of gaze and reaching targets, and studied the neural activity of single V6A cells while the eyes and reaching targets were arranged in different spatial configurations (peripheral and foveal combinations). Target position influenced neural activity in all stages of the task, from visual presentation of target and movement planning, through reach execution and holding time. The majority of neurons preferred reaches directed toward peripheral targets, rather than foveal. Most neurons discharged in both premovement and action epochs. In most cases, reaching activity was tuned coherently across action planning and execution. When reaches were planned and executed in different eye/target configurations, multiple analyses revealed that few neurons coded reaching actions according to the absolute position of target, or to the position of target relative to the eye. The majority of cells responded to a combination of both these factors. These data suggest that V6A contains multiple representations of spatial information for reaching, consistent with a role of this area in forming cross-reference frame representations to be used by premotor cortex.

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TL;DR: Visual performance after adaptation is dependent on the lateral extent of the adaptation stimulus, and foveal contrast sensitivity improved in the mid spatial frequency region after small field blur adaptation.

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TL;DR: It is concluded that although there are some qualitative differences between human and ideal search behavior, humans make principled adjustments in their search behavior as ambient light level decreases.

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TL;DR: It is argued that the combination of the large magnification factor and the impressive ability of the cerebral cortex to learn to recognize arbitrary patterns, might outweigh the disadvantages of bypassing earlier processing stages and makes V1 a viable option for the restoration of vision.

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TL;DR: Optical coherence tomography offers a potential biomarker tool in Parkinson's disease and a mathematical model quantifying symmetry, breadth, and depth of the fovea was applied.
Abstract: Background Optical coherence tomography offers a potential biomarker tool in Parkinson's disease (PD). A mathematical model quantifying symmetry, breadth, and depth of the fovea was applied. Methods Nintey-six subjects (72 PD and 24 healthy controls) were included in the study. Macular scans of each eye were obtained on two different optical coherence tomography devices: Cirrus and RTVue. Results The variables corresponding to the cardinal gradients of the fovea were the most sensitive indicators of PD for both devices. Principal component analysis distinguished 65% of PD patients from controls on Cirrus, 57% on RTVue. Conclusion Parkinson's disease shallows the superior/inferior and to a lesser degree nasal-temporal foveal slope. The symmetry, breadth, and depth model fits optical coherence tomography data derived from two different devices, and it is proposed as a diagnostic tool in PD. © 2015 International Parkinson and Movement Disorder Society

Journal ArticleDOI
TL;DR: Computed tomography arthrography with a radial plane view exhibited enhanced specificity and positive predictive value when a type 3 or 4 lesion was identified in the detection of a TFCC foveal tear compared with historical controls.
Abstract: Purpose To classify triangular fibrocartilage complex (TFCC) foveal lesions on the basis of computed tomography (CT) arthrography using a radial plane view and to correlate the CT arthrography results with surgical findings. We also tested the interobserver and intra-observer reliability of the radial plane view. Methods A total of 33 patients with a suspected TFCC foveal tear who had undergone wrist CT arthrography and subsequent surgical exploration were enrolled. We classified the configurations of TFCC foveal lesions into 5 types on the basis of CT arthrography with the radial plane view in which the image slices rotate clockwise centered on the ulnar styloid process. Sensitivity, specificity, and positive predictive values were calculated for each type of foveal lesion in CT arthrography to detect foveal tears. We determined interobserver and intra-observer agreements using kappa statistics. We also compared accuracies with the radial plane views with those with the coronal plane views. Results Among the tear types on CT arthrography, type 3, a roundish defect at the fovea, and type 4, a large defect at the overall ulnar insertion, had high specificity and positive predictive value for the detection of foveal tears. Specificity and positive predictive values were 90% and 89% for type 3 and 100% and 100% for type 4, respectively, whereas sensitivity was 35% for type 3 and 22% for type 4. Interobserver and intra-observer agreement was substantial and almost perfect, respectively. The radial plane view identified foveal lesion of each palmar and dorsal radioulnar ligament separately, but accuracy results with the radial plane views were not statistically different from those with the coronal plane views. Conclusions Computed tomography arthrography with a radial plane view exhibited enhanced specificity and positive predictive value when a type 3 or 4 lesion was identified in the detection of a TFCC foveal tear compared with historical controls. Type of study/level of evidence Diagnostic II.

Journal ArticleDOI
TL;DR: A processing advantage for emotional words relative to emotionally neutral stimuli in foveal and parafoveal vision is suggested and implications for the notion of attention attraction due to emotional content are discussed.
Abstract: Despite the well-known influence of emotional meaning on cognition, relatively less is known about its effects on reading behavior. We investigated whether fixation behavior during the reading of Chinese sentences is influenced by emotional word meaning in the parafovea. Two-character target words embedded into the same sentence frames provided emotionally positive, negative, or neutral contents. Fixation durations on neutral pretarget words were prolonged for positive parafoveal words and for highly frequent negative parafoveal words. In addition, fixation durations on foveal emotional words were shorter than those on neutral words. We also found that the role of emotional words varied as a function of their valence during foveal and parafoveal processing. These findings suggest a processing advantage for emotional words relative to emotionally neutral stimuli in foveal and parafoveal vision. We discuss implications for the notion of attention attraction due to emotional content.