Vision Loss Impact on Navigation in Virtual Reality

Cortically Blind Group: Inclusion Criteria: Residents of the United States or Canada Presence of one-sided stroke or stroke-like damage to primary visual cortex or its immediate afferent white matter sustained within the specified age range of 21 - 75 years (verified by MRI and/or CT scans) Reliable visual field defects in both eyes (homonymous defects) as measured by Humphrey or equivalent perimetry. Willing, able, and competent to provide their own informed consent Cognitively able, responsible to understand written and oral instructions in English Emmetropic or else wear corrective contact lenses inside the virtual reality headset Exclusion Criteria: Those who have never driven or earned a drivers' license Past or present ocular disease interfering with visual acuity Best corrected visual acuity (BCVA) worse than 20/40 in either eye Sustained damage to the dorsal lateral geniculate nucleus Presence of diffuse, whole-brain degenerative processes Presence of brain damage deemed by study staff to potentially interfere with outcome measures History of traumatic brain injury Documented history of drug/alcohol abuse Diagnosis of cognitive or seizure disorders Diagnosis of one-sided attentional neglect Control Group: Inclusion Criteria: Normal or corrected-to-normal vision, who are between the ages of 21 and 75 years of age, roughly matched to the age of CB subjects enrolled above Competent and responsible, as determined by the Principal Investigator Willing, able, and competent to provide their own informed consent Normal cognitive abilities, be able to understand written and oral instructions in English Emmetropic or else wear corrective contact lenses inside the virtual reality headset Exclusion Criteria: Subjects who have never driven or earned a drivers' license BCVA worse than 20/40 in either eye Presence of vision loss from ocular diseases or disorders Presence of a visual field defect Inability to wear corrective contact lenses inside the virtual reality helmet if required to see clearly Subjects with a history of neurological disorders Subjects with a history of TBI Persons who lack the competence or are otherwise unable to perform the visual testing as directed.