Research

CVI and Neuroplasticity 

CVI is a growing public health concern and more research is needed to better understand the underlying biology of CVI and the unique developmental and educational needs of individuals with CVI.1 Dr. Lotfi B. Merabet, director of The Laboratory for Visual Neuroplasticity at the Schepens Eye Research Institute of Mass. Eye and Ear, is dedicated to advancing research of CVI. 

"In developed countries including the United States, CVI is the leading cause of permanent visual impairment in children, and is characterized by visual dysfunction primarily associated with damage to central brain structures as opposed to the eyes. Despite this significant public health concern, the neurophysiology of this condition remains poorly understood, and more research is needed to fully understand how the developing brain reorganizes itself in response to early damage.

The goal of this investigation is to establish a conceptual framework relating sensory function with structural and functional brain reorganization in CVI. In this effort, we use high resolution structural reconstruction and characterization of the white matter pathways of the brain using diffusion based imaging (specifically, High Angular Resolution Imaging, or HARDI). We employ behavioral assessments integrating virtual reality (VR), psychometric sequences, and eye/gesture tracking technology. These novel techniques allow us to characterize visual dysfunctions beyond what is done in the standard clinical settings using scenarios that more closely approximate real world situations."2

Dr. Lotfi Merabet, OD, PhD, MPH

Director, The Laboratory for Visual Neuroplasticity

Dr. Merabet with Henry (CVI, Phase II)
Dr. Merabet with Henry (CVI, Phase II)

CVI vs. Ocular Visual Impairment: The Impact on Developmental Neuroplasticity

Figure 1: "White matter reconstructions (shown in sagittal view) of three main pathways involved in the processing of visual information, namely the superior longitudinal fasciculus (SLF; the neuroanatomical correlate of the dorsal visual processing stream), inferior longitudinal fasciculus (ILF; the ventral visual processing stream), and inferior fronto-occipital fasciculus (IFOF; mediating visual attention and orienting)."3 Read the full article.

Control vs. CVI: Brain analysis video illustrating differences in the integrity of key visual pathways (MRI, HARDIBrain, HARDIpath)

Object Crowding: Control-vs-CVI

Virtual Toy Box Study

"Eye tracking data for an individual with CVI is compared to an age matched neuro-typical sighted control (A). The heat maps represent the aggregate of the eye movement data captured during the task. Notice that for the control participant, the eye movements remain tight and concentrated even when the level of task difficulty increases (i.e. a greater number of toy distractors are present). In contrast, notice how the eye movements are less tightly clustered for the CVI participant at low task difficulty, and then become even more widespread at the high task difficulty."4

Human Crowding: Control-vs-CVI

Virtual Corridor Study

"Eye tracking data for an individual with CVI is compared to an age matched neuro-typical sighted control (A). The heat maps represent the aggregate of the eye movement data captured during the task. Notice that for the control participant, the eye movements remain tight and concentrated even when the level of task difficulty increases (i.e. a greater number of people distractors are present). In contrast, notice how the eye movements are less tightly clustered for the CVI participant at low task difficulty, and then become even more horizontally widespread at the high task difficulty. This trend is also evident from the group data collected (B)."5

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Medical Resources

1Mass. Eye and Ear Communications (2018, Feb 12). Blindness of the Brain: Explaining CVI.  Retrieved from https://focus.masseyeandear.org/blindness-brain-explaining-cvi/
2The Laboratory for Visual Neuroplasticity (2019). Neuroplasticity Associated With Cortical/Cerebral Visual Impairment. Retrieved from https://scholar.harvard.edu/merabetlab/research 
3Martín, M. B., Santos-Lozano, A., Martín-Hernández, J., López-Miguel, A., Maldonado, M., Baladrón, C., … Merabet, L. B. (2016). Cerebral versus Ocular Visual Impairment: The Impact on Developmental Neuroplasticity. Frontiers in psychology, 7, 1958. doi:10.3389/fpsyg.2016.01958
4The Laboratory for Visual Neuroplasticity (2018, January 24). Virtual Toy Box Study [Facebook post]. Retrieved from https://www.facebook.com/CVI.Neuroplasticity/
5The Laboratory for Visual Neuroplasticity (2018, January 24). Virtual Corridor Study [Facebook post]. Retrieved from https://www.facebook.com/CVI.Neuroplasticity/

 

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