NJIT Physics Department Seminar
October 19th, Monday
The Underlying Mechanism of Vision Therapy revealed using Functional Imaging
Prof. Tara Alvarez
Dept. of Biomedical Engineering, NJIT
(Biophysics, Host: Thomas/Dias)
Time: 11:45am-12:45pm with 11:30am tea time
Room: ECE 202
Convergence insufficiency (CI), a prevalent binocular vision disorder in adults and children, is characterized by greater exophoria at near than at distance, reduced fusional convergence amplitude and receded near point of convergence. CI is associated with symptoms including double/blurred vision, eyestrain, and headaches when engaged in reading or other near work. Dr. Alvarez and colleagues published the first data of functional activity using functional MRI (fMRI) with convergence eye movements correlated to vision function in CI patients before and after Office-Based Vergence and Accommodative Therapy with home reinforcement (OBVAT). The recent NEI/NIH multi-center randomized clinical trial, the Convergence Insufficiency Treatment Trial (CITT), demonstrated the effectiveness of OBVAT for CI, reporting 73% of patients have sustained improvements of vision function and symptoms. Our quantitative methods integrated with established CITT standards address important questions about the underlying neural substrates and changes in convergence presumed to be evoked by OBVAT. We combine objective eye movement recordings and fMRI, to take a first critical step to answer what neural substrates change within the visual system as the near point of convergence and convergence amplitudes improve with therapy. The relationship between convergence eye movements and fMRI will be discussed. Measurements from the CI patients were obtained before and after 18 hours of vision therapy. Neural substrates were stimulated using an fMRI block design composed of sustained fixation compared to vergence eye movements. Individual subject reference vectors were computed using a data-driven independent component analysis (ICA) of a group of time series. After vision therapy, the blood oxygenation level dependent (BOLD) percent signal change increased in the frontal eye fields (FEF), posterior parietal cortex (PPC) and cerebellar vermis (CV). Second, the task induced functional connectivity improved in the FEF, PPC, and CV. Last, the BOLD percent signal change within FEF and CV significantly correlated to the clinically developed symptom survey.
Tara Alvarez is Professor of Biomedical Engineering at NJIT. After her Ph.D. (BME, Rutgers) and research at Bell Labs, she helped found NJIT’s BME Department in 2001. Her laboratory seeks to understand fundamental mechanisms of oculomotor learning. She actively studies how clinical vision therapy leads to sustained reduction in visual dysfunction. (5% of children and 40-50% of traumatic brain injured patients suffer oculomotor dysfunction.) Dr. Alvarez is known for demonstrating how vision therapy alters neural oculomotor control using combined measurements of functional imaging (fMRI) and eye movements. This knowledge improves therapeutic efficacy while decreasing cost – especially for children and those with brain injury. Her work is funded by NIH, where her most recent grant placed in the top 5%, NSF and Essilor International. She has 125 peer reviewed publications and 4 patents. She has been recognized by numerous awards: NSF CAREER (2005), Best Scientific Achievement (NORA, 2008), Outstanding Woman of Science (NJABR, 2008), NJIT Excellence in Education (2013), NJIT Excellence in Research (2015), Thomas Edison Award (NJ R&D Council, 2015). She serves on the editorial board of Journal of Eye Movement Research and actively reviews for 7 other journals.