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Prior oculomotor studies have investigated the various effects of short-term modification on vergence, saccadic and smooth pursuit eye movements. Previous vergence studies have concentrated on step modification stimuli. Few have investigated the effects of modification on vergence ramp movements. Thus, this study explores the trends observed within a short-term modification experiment studying smoothly...
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...
It is known that ocular motor dysfunction can be treated by utilizing vision therapy or vision training. However, the question remains on whether binocularly normal persons will have any significant change to their vergence ocular motor system if they go through vision training sessions. This study intends to explore that question. A total of five (n = 5) binocularly normal persons participated in...
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...
Vergence eye movements are critical in daily routines. These movements navigate three-dimensional space. Convergence and divergence eye movements are used to create and maintain stereoscopic vision. This study investigates differences in vergence eye movements between the left and right eye movement. Eye movements were collected using a costume haploscope design paired with our stimulus-presentation...
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...
Saliency of the stimuli presumably plays a critical role in vision rehabilitation. This study sought to determine whether a peripheral or near central target influenced the peak velocity of convergence which may have an impact on visual saliency. Blue line stimuli, one without any distracting peripheral background and two with distracting background were given to four subjects within a haploscope...
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...
Glaucoma is the degeneration of the optic nerve head caused by elevated intraocular pressure (IOP) and diurnal variations. It is the second leading cause of blindness. Proper treatment requires IOP to be monitored and maintained. Goldmann applanation tonometry is the clinical gold standard measured in the physician's office quarterly for those who are glaucoma suspects. It requires a local anesthetic...
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...
The focus of this paper is to investigate the significance of the cerebral vascular enhancement effect on diffusion tensor imaging (DTI) datasets and in establishing appropriate DTI imaging protocols. Two DTI scans are performed on each subject during the same imaging session. Between DTI scans, 22 minutes of a visual tracking experiment and 3 minutes of an alternating breath hold experiment are performed...
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...
This study's aim is to ascertain whether the amount of saccades during convergence has any relation to a person's preference of progressive additive lenses (PALs). Since patients who are better adapters to PALs have faster vergence dynamics, we presume those who do not adapt well must have an alternative to compensate for their slower vergence system. The goal of this experiment is to compare the...
Presbyopia, a degenerative condition, which decreases accommodation, sets in approximately at the age of forty. One approach to correct presbyopia is the use of bifocal or progressive lenses. Naturally, some people are more prone to adapt to wearing progressive lenses than others. The vergence system, which controls the inward and outward turning of the eyes, is a system which supports viewing objects...
The ability to change or adapt is critical in the survival of a species. Research has shown that the dynamics of disparity vergence eye movements, the inward (convergence) or outward (divergence) turning of the eyes, are malleable and depend to some extent on the amplitude of preceding stimuli. Divergence eye movements are dependent on initial stimulus position where responses that occur closer to...
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