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A ‘random walk’ visual training system was developed to be presented on a haploscope. This test entailed a series of 2 and 4 deg step changes located at different vergence angles presented for an unpredictable amount of time. This training sequence was designed to serve as a control measurement for future comparison to evaluate whether three dimensional gaming stimulates adaptation to the vergence...
While a body of literature relating cognition and oculomotor performance exists, a better understanding of these processes would help facilitate the development of effective treatments for patients suffering various neurological disorders, such as Multiple Sclerosis (MS), Huntington's Disease, or a traumatic brain injury. To examine the relationship between the two, we sought to measure cognition...
While fMRI has identified which regions of interests (ROI) are functionally active during a vergence task (the inward or outward rotation of eyes), the functional connectivity between ROIs is less understood. This study tested the following hypotheses: 1) significant functional connectivity would be observed between the frontal eye fields (FEF), the posterior parietal cortex (PPC) and the cerebellar...
Although a great amount of research studying oculomotor function has been conducted, a full understanding of how it relates to and is affected by neurological and neurodegenerative disorders is still warranted. This experiment seeks to build a system comparing pro-saccades, gap saccades, and overlap saccadic eye movements. Gap saccades extinguish the visual targets for 200 msec while overlap saccades...
Throughout the day, the human visual system acquires information using saccade and vergence eye movements. Previously, functional MRI (fMRI) experiments have shown both shared neural resources and spatial differentiation between these two systems. FMRI experiments can reveal which regions are activated within an experimental task but do not yield insight into how regions of interest (ROIs) interact...
A pure vergence stimulus requires the two eyes to turn equally inward or outward theoretically resulting in a pure symmetrical vergence response. However, saccades, a rapid conjugate eye movement, are frequently observed in vergence responses. This investigation sought to systematically quantify whether the occurrence of saccades within symmetrical vergence responses is correlated to vergence peak...
During symmetrical vergence movements, saccades are frequently observed. This research tests the hypothesis that the brain initiates a saccade to facilitate a vergence movement when it has slower dynamics. This study analyzes the frequency of saccades in four healthy controls during near and far ranges for both convergence and divergence movements. The experiment suggests that the frequency of saccades...
Vergence eye movements are the inward and outward turning of the eyes and contemporary views believe these movements are mediated by a preprogramming and feedback controlled mechanism. The individual left and right eye responses have been reported to have large dynamic asymmetries between the individual eye movements. One hypothesis to explain the observed asymmetry is the preprogrammed transient...
Presbyopia is part of the aging process where the eye losses the ability to focus at different depths. Progressive additive lenses (PALs) are routinely prescribed to facilitate the accommodation system for those with presbyopia. However, it is unknown why some individuals are more likely to adapt to PALs compared to others. Eighteen subjects who had all tried PALs participated in a vergence motor...
This research used the Infomax ICA algorithm to search for independent circuits within the functional activity evoked during saccadic and vergence tracking fMRI experiments. Image processing determined independent components from each subject's data and then identified which components had high correlation between subjects. Using the individual independent components that had high correlation between...
Visual fatigue is defined as weariness or discomfort localized in either the head or the eye after a visually demanding task. The etiology of visual fatigue is insufficiently understood in vision research. This study investigates the correlation between changes of near-dissociated phoria versus vergence dynamics defined as the ratio of convergence average peak velocity to divergence average peak velocity...
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