Overview

This research aims to examine changes in plastic potential of the visual system with time from stroke affecting primary visual cortex. We will measure structural and mechanistic aspects of progressive degeneration along the early visual pathways, correlating them with changes in visual performance, and in responsiveness to visual restoration training. This project will advance both scientific knowledge, as well as technical capability and clinical practices for restoring vision and quality of life for people suffering from cortical blindness.

Eligibility

Inclusion Criteria:

• Residents of US and Canada
• MRI and/or CT scans showing evidence of one-sided / unilateral stroke or stroke-like damage to the primary visual cortex or its immediate afferent white matter sustained less than 6-months prior to enrollment
• Reliable visual field defects in both eyes as measured by Humphrey, Macular Integrity Assessment (MAIA), Goldmann, and/or equivalent perimetry. This deficit must be large enough to enclose a 5-deg diameter visual stimulus.
• Ability to fixate on visual targets reliably for 1000ms (as demonstrated by visual fields, and verified in study participation)
• Willing and safely able to undergo magnetic resonance imaging (MRI) scanning
• Willing, able, and competent to provide informed consent
• Fluent in written and spoken English
• Cognitively able, responsible, and willing to complete daily visual training independently at home for several months.

Exclusion Criteria:

• Past or present ocular disease interfering with vision
• Best corrected visual acuity worse than 20/40 in either eye
• Presence of damage to the dorsal Lateral Geniculate Nucleus, as shown on MRI/CT scans
• Diffuse, whole brain degenerative processes
• Brain damage deemed by study staff to potentially interfere with training ability or outcome measures
• History of traumatic brain injury
• Documented history of drug/alcohol abuse
• Currently use of neuroactive medications which would impact training, as determined by PI
• Cognitive or seizure disorders
• One-sided attentional neglect
• Inability to perform the visual training exercises as directed