Page mode reading with simulated scotomas: Oculo-motor patterns

Scherlen, Anne Catherine; Bernard, Jean Baptiste; Calabrèse, Aurélie; Castet, Éric

doi:10.1016/j.visres.2008.06.005

Cited by 32 publications

(23 citation statements)

References 38 publications

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“…In this study we found a comparable increase in fixation duration, but this failed to reach significance. Our results for fixation duration conflict with other studies that have used artificial scotomas with different tasks, including reading 30 and visual search tasks in highly regular search arrays 6, 10 . These tasks did not use a natural images but instead resolution-dependent stimuli.…”

Section: Discussioncontrasting

confidence: 99%

Impact of Simulated Central Scotomas on Visual Search in Natural Scenes

McIlreavy¹,

Fiser²,

Bex³

2012

Optometry and Vision Science

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Purpose In performing search tasks, the visual system encodes information across the visual field at a resolution inversely related to eccentricity and deploys saccades to place visually interesting targets upon the fovea where resolution is highest. The serial process of fixation, punctuated by saccadic eye movements, continues until the desired target has been located. Loss of central vision restricts the ability to resolve the high spatial information of a target, interfering with this visual search process. We investigate oculomotor adaptations to central visual field loss with gaze-contingent artificial scotomas. Methods Spatial distortions were placed at random locations in 25° square natural scenes. Gaze-contingent artificial central scotomas were updated at the screen rate (75Hz) based on a 250Hz eyetracker. Eight subjects searched the natural scene for the spatial distortion and indicated its location using a mouse-controlled cursor. Results As the central scotoma size increased, the mean search time increased [F(3,28)= 5.27, p= .05] and the spatial distribution of gaze points during fixation increased significantly along the x [F(3,28)= 6.33, p= .002] and y [F(3,28)= 3.32, p= .034] axes. Oculomotor patterns of fixation duration, saccade size and saccade duration did not change significantly, regardless of scotoma size. Conclusions There is limited automatic adaptation of the oculomotor system following simulated central vision loss.

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Section: Discussioncontrasting

confidence: 99%

Impact of Simulated Central Scotomas on Visual Search in Natural Scenes

McIlreavy¹,

Fiser²,

Bex³

2012

Optometry and Vision Science

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“…Some recent reviews show the difficulty of providing a clear-cut understanding of crowding (Levi, 2008;Strasburger, Rentschler, & Jüttner, 2011). Crowding has also been invoked to account for reading deficits either in amblyopia (Levi, Song, & Pelli, 2007), in low vision (Wallace, Chiu, Nandy, & Tjan, 2013;Wallace, Chung, & Tjan, 2017), or in developmental dyslexia (Martelli, Filippo, Spinelli, & Zoccolotti, 2009) although this remains a controversial issue both in low vision (Bernard, Scherlen, & Castet, 2007;Calabrèse et al, 2010;Chung, 2004;Scherlen, Bernard, Calabrèse, & Castet, 2008) and dyslexia (Doron, Manassi, Herzog, & Ahissar, 2015;Ramus & Ahissar, 2012).…”

Section: Introductionmentioning

confidence: 99%

Letter and symbol identification: No evidence for letter-specific crowding mechanisms

et al. 2017

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It has been proposed that letters, as opposed to symbols, trigger specialized crowding processes, boosting identification of the first and last letters of words. This hypothesis is based on evidence that single-letter accuracy as a function of within-string position has a W shape (the classic serial position function [SPF] in psycholinguistics) whereas an inverted V shape is obtained when measured with symbols. Our main goal was to test the robustness of the latter result. Our hypothesis was that any letter/symbol difference might result from short-term visual memory processes (due to the partial report [PR] procedures used in SPF studies) rather than from crowding. We therefore removed the involvement of short-term memory by precueing target-item position and compared SPFs with precueing and postcueing. Perimetric complexity was stringently matched between letters and symbols. In postcueing conditions similar to previous studies, we did not reproduce the inverted V shape for symbols: Clear-cut W shapes were observed with an overall smaller accuracy for symbols compared to letters. This letter/symbol difference was dramatically reduced in precueing conditions in keeping with our prediction. Our results are not consistent with the claim that letter strings trigger specialized crowding processes. We argue that PR procedures are not fit to isolate crowding processes.

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“…In gaze-contingent paradigms, the gaze location is monitored with an eyetracker and is then used to manipulate the visual information the observer is currently looking at. In one variant of such gaze-contingent paradigms, the moving mask technique (Rayner & Bertera, 1979), foveal information is degraded in order to investigate scene and object perception (Henderson, McClure, Pierce, & Schrock, 1997;Larson & Loschky, 2009;van Diepen, Ruelens, & d'Ydewalle, 1999), eye movement patterns in visual search (Bertera, 1988;Bertera & Rayner, 2000;Cornelissen, Bruin, & Kooijman, 2005) and reading (Fine & Rubin, 1999;Scherlen, Bernard, Calabrese, & Castet, 2008), and highlevel cognitive functioning such as visual context learning (Geringswald, Baumgartner, & Pollmann, 2012) when the observer is faced with a central scotoma.…”

Section: Introductionmentioning

confidence: 99%

A behavioral task for the validation of a gaze-contingent simulated scotoma

2013

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Gaze-contingent displays provide a valuable method in visual research for controlling visual input and investigating its visual and cognitive processing. Although the body of research using gaze-contingent retinal stabilization techniques has grown considerably during the last decade, only few studies have been concerned with the reliability of the specific real-time simulations applied. Using a Landolt ring discrimination task, we present a behavioral validation of gaze-contingent central scotoma simulation in healthy observers. Importantly, behavioral testing is necessary to show whether the simulation impairs foveal processing of visual information. This test becomes even more crucial when researchers are faced with null results in a task performed with the scotoma, as compared with a control condition. It must be ruled out that the lack of behavioral effects results from a type II error caused by improper implementation before conclusions about foveal contributions to the given task may be drawn. In our experiment, the scotoma effectively prevented foveal processing of the visual stimuli, leading to significantly reduced response accuracies, as compared with unimpaired vision.Moreover, the final fixation at the time of the participants' responses was placed close to the target position in the unimpaired condition, whereas the distance to the target was enhanced with the scotoma, indicating that the observers were not able to discriminate visual target stimuli from distractors, due to the scotoma. The present work presents a validated behavioral testing method for the efficiency of gaze-contingent scotoma simulations, including code for implementation. In addition, solutions for common methodological problems are discussed.

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Page mode reading with simulated scotomas: Oculo-motor patterns

Cited by 32 publications

References 38 publications

Impact of Simulated Central Scotomas on Visual Search in Natural Scenes

Impact of Simulated Central Scotomas on Visual Search in Natural Scenes

Letter and symbol identification: No evidence for letter-specific crowding mechanisms

A behavioral task for the validation of a gaze-contingent simulated scotoma

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