Overview
The purpose of this research is to better understand the impact of cortically-induced blindness (CB) and the compensatory strategies subjects with this condition may develop on naturalistic behaviors, specifically, driving. Using a novel Virtual Reality (VR) program, the researchers will gather data on steering behavior in a variety of simulated naturalistic environments. Through the combined use of computer vision, deep learning, and gaze-contingent manipulations of the visual field, this work will test the central hypothesis that changes to visually guided steering behaviors in CB are a consequence of changes to the visual sampling and processing of task-related motion information (i.e., optic flow).
Eligibility
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.