Impact of Central Vision Loss on Eye Movements and Time-to-Contact Judgments

• Main Author: Cloutier, Melissa
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2023
• Subjects: Ophthalmology; Optometry; Psychology
• ISBN: 9798383415696

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.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.