Impact of Simulated Central Scotomas on Visual Search in Natural Scenes

Abstract

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.

Macular degeneration affects eye movement behavior during visual search

“…This way, we were able to compare the PRL-based reference frame with a fovea-based reference frame either using the fovea or a peripheral location. Previous studies have revealed that inducing a simulated central scotoma in normally sighted participant induces impairments in visual search tasks, such as increase in search time and fixation duration (Bertero, 1988; Cornelissen et al, 2005; McIlreavy et al, 2012) and a decrease of search facilitation for repeated displays (Geringswald et al, 2012). To compare the search behavior in different types of visual search, the experiment contained two conditions: in the first condition the target was an unfilled circle hidden among c-shaped distractors of equal size (serial condition) and in the second condition the target was a filled circle (pop-out condition).…”

Characterizing and automatically detecting smooth pursuit in a large-scale ground-truth data set of dynamic natural scenes

“…For example, throughout this manuscript we use the term ''naturalistic'' in order to describe the stimulus scenes in our data set. We use this term in the meaning of ''imitating real life or nature'' in accordance with other literature (Krieger, Rentschler, Hauske, Schill, & Zetzsche, 2000;Torralba, Oliva, Castelhano, & Henderson, 2006;Dorr et al, 2010;Tatler, Hayhoe, Land, & Ballard, 2011;McIlreavy, Fiser, & Bex, 2012;Smith & Mital, 2013;Parks, Borji, & Itti, 2015;Leder, Mitrovic, & Goller, 2016;Ramkumar et al, 2016;Foulsham & Kingstone, 2017;Schomaker, Walper, Wittmann, & Einhäuser, 2017;White et al, 2017). We describe our experimental set-up as naturalistic in part to contrast it with synthetic stimuli with prescribed, isolated eye movements often used for studies involving smooth pursuit (Vidal et al, 2012;Santini et al, 2016): Naturalistic stimuli represent a more complex set of visual inputs that affect oculomotor behavior (Monache, Lacquaniti, & Bosco, 2019), and the idea that the visual system is optimized to efficiently encode the inputs that surrounded our ancestors during evolution is well established (Field, 1987;Atick & Redlich, 1992).…”

Visual Search in the Detection of Retinal Injury: A Feasibility Study

“…There is currently a fairly large body of literature on the effects of foveal and large parafoveal scotoma and general peripheral field restrictions, both simulated and in diseased eyes, on behaviors ranging from visual search, tracking, to navigation and reading. [8][9][10][27][28][29] In contrast, and to our knowledge, there have been no studies of the effects on vision of small scotoma in the central 20°.…”

“…Simulation studies show that even small lesions in the fovea have the potential to cause severe disruptions of vision and degradation in the performance of tasks such as visual search and tracking. [8][9][10] Lesions outside of the fovea may or may not be immediately noticed unless they are extensive in size. Lesions that are small and localized and scattered across the retina outside the fovea may be particularly difficult to detect.…”