Visual Search Training and Obstacle Avoidance in Adults with Visual Impairments

Kuyk, Thomas; Liu, Lei; Elliott, Jeffry L.; Fuhr, Patti S.

doi:10.1177/0145482x1010400405

Cited by 22 publications

(20 citation statements)

References 13 publications

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“…Moreover, there was also no improvement in regard to safety in either of the training groups, which indicates that the subjects did not become familiar with the course by repetition, as we would then expect fewer collisions. This finding is in contrast with the findings by Kuyk et al [ 19 ], where walking speed did not improve after EST training in AMD patients, who were assumed to have normal peripheral vision. However, the subjects in the current study significantly reduced the number of collisions with obstacles only in the dim walking conditions.…”

Section: Discussioncontrasting

confidence: 99%

“…This demonstrates that top-down information processing is involved in successful vision rehabilitation. Similar results were obtained by Kuyk and colleagues who studied the effect of exploratory saccade training (EST) in a large cohort of patients with vision loss [ 19 ]. They found that patients' performance in exploratory tasks improved with training and led to fewer collisions with obstacles under dim conditions.…”

Section: Introductionsupporting

confidence: 84%

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Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study

et al. 2016

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PurposeDegenerative retinal diseases, especially retinitis pigmentosa (RP), lead to severe peripheral visual field loss (tunnel vision), which impairs mobility. The lack of peripheral information leads to fewer horizontal eye movements and, thus, diminished scanning in RP patients in a natural environment walking task. This randomized controlled study aimed to improve mobility and the dynamic visual field by applying a compensatory Exploratory Saccadic Training (EST).MethodsOculomotor responses during walking and avoiding obstacles in a controlled environment were studied before and after saccade or reading training in 25 RP patients. Eye movements were recorded using a mobile infrared eye tracker (Tobii glasses) that measured a range of spatial and temporal variables. Patients were randomly assigned to two training conditions: Saccade (experimental) and reading (control) training. All subjects who first performed reading training underwent experimental training later (waiting list control group). To assess the effect of training on subjects, we measured performance in the training task and the following outcome variables related to daily life: Response Time (RT) during exploratory saccade training, Percent Preferred Walking Speed (PPWS), the number of collisions with obstacles, eye position variability, fixation duration, and the total number of fixations including the ones in the subjects' blind area of the visual field.ResultsIn the saccade training group, RTs on average decreased, while the PPWS significantly increased. The improvement persisted, as tested 6 weeks after the end of the training. On average, the eye movement range of RP patients before and after training was similar to that of healthy observers. In both, the experimental and reading training groups, we found many fixations outside the subjects' seeing visual field before and after training. The average fixation duration was significantly shorter after the training, but only in the experimental training condition.ConclusionsWe conclude that the exploratory saccade training was beneficial for RP patients and resulted in shorter fixation durations after the training. We also found a significant improvement in relative walking speed during navigation in a real-world like controlled environment.

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Section: Discussioncontrasting

confidence: 99%

Section: Introductionsupporting

confidence: 84%

Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study

et al. 2016

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“…Several recent studies have reported benefits of visual search training for mobility in patients with low vision, mostly under conditions of low luminance or contrast 14, 15 . The present results suggest that the main oculomotor change with the use of peripheral vision is an increase in fixation instability.…”

Section: Discussionmentioning

confidence: 99%

“…Recent work suggests that training on a visual search task can improve mobility performance under low light conditions for people with visual impairments including AMD 14, 15 . To develop novel rehabilitation interventions, a better understanding of the short-term oculomotor adaptations of the visual system following scotoma onset is needed.…”

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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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“…Visual search in people with visual impairment has been suggested as a predictor for mobility and performance of other daily activities (Kuyk et al 2005). There is evidence for the effectiveness of eye movement training on visual search in congenital prosopagnosia (Schmalzl et al 2008), following brain damage (Bouwmeester et al 2007), and for improved visual search and mobility performance in people with visual impairment of ocular origins following repeated practice of an item-based search task (Kuyk et al 2010;Liu et al 2007). These types of findings could lead to interventions and alternative approaches to management of patients.…”

Section: Open Peer Commentarymentioning

confidence: 99%

The impending demise of the item in visual search

Hulleman¹,

Olivers²

2015

Behav Brain Sci

102

118

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The way the cognitive system scans the visual environment for relevant information - visual search in short - has been a long-standing central topic in vision science. From its inception as a research topic, and despite a number of promising alternative perspectives, the study of visual search has been governed by the assumption that a search proceeds on the basis of individual items (whether processed in parallel or not). This has led to the additional assumptions that shallow search slopes (at most a few tens of milliseconds per item for target-present trials) are most informative about the underlying process, and that eye movements are an epiphenomenon that can be safely ignored. We argue that the evidence now overwhelmingly favours an approach that takes fixations, not individual items, as its central unit. Within fixations, items are processed in parallel, and the functional field of view determines how many fixations are needed. In this type of theoretical framework, there is a direct connection between target discrimination difficulty, fixations, and reaction time (RT) measures. It therefore promises a more fundamental understanding of visual search by offering a unified account of both eye movement and manual response behaviour across the entire range of observed search efficiency, and provides new directions for research. A high-level conceptual simulation with just one free and four fixed parameters shows the viability of this approach.

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Visual Search Training and Obstacle Avoidance in Adults with Visual Impairments

Cited by 22 publications

References 13 publications

Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study

Eye Movement Training and Suggested Gaze Strategies in Tunnel Vision - A Randomized and Controlled Pilot Study

Impact of Simulated Central Scotomas on Visual Search in Natural Scenes

The impending demise of the item in visual search

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