Tara L. Alvarez

Learn More
PURPOSE This research quantified clinical measurements and functional neural changes associated with vision therapy in subjects with convergence insufficiency (CI). METHODS Convergence and divergence 4° step responses were compared between 13 control adult subjects with normal binocular vision and four CI adult subjects. All CI subjects participated in 18(More)
PURPOSE To assess the potential peak velocity asymmetry between the left-eye and right-eye movement responses stimulated by symmetrical vergence steps in those with normal binocular vision and those with convergence insufficiency (CI) before and after vergence training. This study also evaluated whether vergence training influenced convergence peak velocity(More)
PURPOSE The purpose of this study was to investigate the relationship between phoria and the dynamics of vergence eye movements as described by the ratio of convergence average peak velocity to divergence average peak velocity, termed the vergence peak velocity ratio. METHODS Phoria and vergence step responses were recorded. Three measures of phoria were(More)
PURPOSE Phoria is used in the diagnosis of binocular dysfunctions, such as convergence insufficiency. A common treatment for convergence insufficiency is vision therapy, yet it is controversial whether the phoria changes as a result of rehabilitation. Phoria can vary due to the duration and/or the type of prior visual tasks. The variability potentially(More)
In a natural environment, saccade and vergence eye movements shift gaze in different directions and distances. In a laboratory setting, targets can be positioned precisely to elicit symmetrical vergence movements; however, saccades occur during the vergence movement even though the stimulus should not stimulate a saccadic response. These saccades may(More)
Previous work has shown that the disparity vergence eye movement system responds to inward (i.e., convergent) ramp stimuli with both smooth and step-like behavior depending on target velocity. The responses to diverging ramp stimuli have not been previously studied, but convergence and divergence responses to other stimuli often show different behaviors.(More)
PURPOSE Eye movement research has traditionally studied solely saccade and/or vergence eye movements by isolating these systems within a laboratory setting. While the neural correlates of saccadic eye movements are established, few studies have quantified the functional activity of vergence eye movements using fMRI. This study mapped the neural substrates(More)
PURPOSE Cortical and subcortical functional activity stimulated via saccade and vergence eye movements were investigated to examine the similarities and differences between networks and regions of interest (ROIs). METHODS Blood oxygenation level-dependent (BOLD) signals from stimulus-induced functional Magnetic Resonance Imaging (MRI) experiments were(More)
PURPOSE The purpose of this study is to investigate the functional neural anatomy that generates vergence eye movement responses from predictive versus random symmetrical vergence step stimuli in humans and compare it to a similar saccadic task via the blood oxygenation level dependent signal from functional MRI. METHODS Eight healthy subjects(More)
Previous studies on the speed and latency of convergence and divergence eye movements have produced varied, sometimes contradictory, results. Four subjects were studied and tracked 4 degrees disparity step changes for convergence and divergence at different initial target positions. Here we report that the dynamics of divergence movements not only differ(More)