Browsing by Author "Cloutier, Melissa"

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    Impact of Central Vision Loss on Eye Movements and Time-to-Contact Judgments
    (2023-11-27) Cloutier, Melissa; DeLucia, Patricia R
    Background: Time-to-contact (TTC) judgments can be influenced by eye movements as well as by multisensory stimuli (i.e., presenting a stimulus that has both an auditory and visual component). To date, no study has investigated the interaction between eye movements and unimodal (visual-only) versus multimodal (audiovisual) presentation on TTC estimates. Further, eye movements differ between individuals with normal vision and individuals with central vision loss during navigation tasks. However, no study has investigated eye movement differences between individuals with normal vision and individuals with central vision loss in a TTC task. The current study investigated (1) if eye movements differed between unimodal and multimodal presentations and if that difference influenced TTC estimates, and (2) whether eye movements differed between individuals with central vision loss and individuals with normal vision. Method: Individuals with normal vision and individuals with central vision loss completed a TTC estimation task in an immersive virtual reality environment. Participants were asked to indicate when they believed the approaching object would reach them, after the object had disappeared in both unimodal and multimodal conditions. Saccade amplitude, saccade duration, and fixation duration were recorded in all trials. ii Results: Results showed that saccadic eye movements predict TTC estimates in the unimodal condition but not in the multimodal condition. Further, for both vision groups (central vision loss and normal vision) in the unimodal condition, TTC estimates increased as saccadic eye movement (i.e., saccade amplitude and saccade fixation) increased. However, there was a greater increase in the central vision loss group compared to the control group. Neither group exhibited an effect of saccadic eye movements on TTC estimates in the multimodal condition. Conclusion: Results suggest that eye movements do not predict TTC estimates in a multimodal condition for both the central vision loss and normal vision groups. Future research should investigate why the addition of an auditory stimulus removed the effect of saccadic eye movements on TTC estimates.
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    Topical Review: Impact of Central Vision Loss on Navigation and Obstacle Avoidance while Walking
    (Wolters Kluwer, 2022) Cloutier, Melissa; DeLucia, Patricia R.
    SIGNIFICANCE : Individuals with central vision loss are at higher risk of injury when walking and thus may limit trips outside the home. Understanding the mobility challenges associated with central vision loss (CVL) can lead to more effective interventions. A systematic literature review focusing on mobility in CVL was conducted. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses method, 2424 articles were identified in 4 databases (PsycINFO, APA PsycArticles, PubMed, and Web of Science). To be included within this review, the study methodology needed to be related to the three components of walking: (1) navigation, defined as the ability to reach a target destination; (2) obstacle avoidance, defined as the ability to avoid collisions with obstacles located at various heights and directions; and (3) street crossing, defined as the ability to both navigate a path and avoid collisions in a traffic environment. The methodology also needed to be empirical. Case studies, unstructured observational studies, studies based on self-report, research proposals, and existing systematic reviews were excluded. Titles, abstracts, and full text of identified articles were screened, yielding 26 articles included in the review. Results showed that, in many tasks, individuals with CVL can accomplish a level of performance comparable with individuals with normal vision. Differences between normal and impaired vision were due to either age or how the groups completed the task. For example, individuals with CVL could cross a street successfully but did so less safely (i.e., smaller safety margins) than individuals with normal vision. To identify new interventions for CVL, future research should focus on the differences in the mechanisms underlying mobility between individuals with normal and impaired vision rather than solely on performance differences.