This is a research study to evaluate the effectiveness of the PAVE (Parallactic Visual-Field Enhancement) System for the treatment of chronic visual field loss due to stroke, traumatic brain injury, or brain surgery. The PAVE regimen involves the use of a virtual reality headset to deliver visual stimulation to subjects diagnosed with visual field loss.

The primary objective is to demonstrate that there is an improvement in the visual field after use of the PAVE therapy over a period of eight weeks with three sessions per week. The primary outcome is an increase in visual field area as measured with Goldmann-type kinetic perimetry.

The secondary outcome will be demonstration that the subjective assessment of visual function using the National Eye Institute Visual Function Questionnaire (NEI-VFQ) is better after PAVE therapy when compared to before therapy.

The participants will visit the investigators office at the start of the study to establish a baseline for visual field size and visual field function. The subject will use PAVE in the office or at home three times per week for eight weeks. There will be twenty four therapy sessions in total. At four weeks the subject will visit the office and have perimetry measurements. At eight weeks the subject will visit the office and have perimetry measurements and complete the NEI-VFQ survey. Four weeks after the completion of the therapy sessions a follow up visit will take place where visual field measurement using kinetic perimetry and NEI-VFQ will be administered.

This clinical investigation will focus on patients with chronic visual field loss following a cerebrovascular accident (CVA), a traumatic brain injury (TBI), or surgery of the brain. The CVA and TBI and some surgeries of the brain may affect bilateral visual fields (homonymous hemianopia, quadrantanopia, or general constriction). While perimetric visual field improvements can occur spontaneously in the first few months after brain injury, after six months the condition is considered chronic and permanent .

This study will include patients at least 6 months after the brain injury event and up to ten years after onset. If available for the study, patients suffering field loss as a result of brain surgery may also be enrolled. All patients shall have a definitive diagnosis of homonymous hemianopia, quadrantanopia, or general constriction. The patients shall have the ability to wear the virtual reality head mounted display HMD for a 30-minute session performed in the clinic at least once per week. Patients will be between 21 and 80 years of age. The clinical study shall be comprised of a single arm with all subjects receiving therapy with the PAVE software on the HMD. The initial sample size will be a minimum of fifteen. Performance will be evaluated using a semiautomated kinetic perimeter (SKP) measurement derived from the Goldmann method.

The goal will be to determine the amount of statistically significant improvement of the visual field for the subjects. Additional endpoints will include the percentage of subjects showing improvement and subjective assessment of the subject's visual performance using the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ).

Inclusion Criteria:

• This study will include patients at least 6 months after the CVA or TBI or brain surgery event and up to ten (10) years after onset
• The patients shall have a definitive diagnosis of homonymous hemianopia or quadrantanopia or generalized constriction.

Exclusion Criteria:

• Presence of any physical, neurological, or mental disability that would interfere with receiving the therapy.
• Concurrent use of another visual therapy
• Concurrent use of medications judged to affect training (amphetamines, dopamine, etc.)
• Presence of ocular or neurological conditions that would interfere with training or cause a visual impairment including no residual vision, disorders of the eye, non-optic nerve heteronymous visual field defects
• Insufficient fixation ability
• Use of life supporting external medical device such as infusion pumps, ventricular assist devices, etc.
• Presence of active implantable medical device including but not limited to cardiac pacemakers, defibrillators, nerve stimulators, cochlear implants, etc.
• Subjects with known photosensitive epilepsy.
• Subjects with chronic active infections on the head and face should be excluded from the study
• Patients with known immune disorders for whom an infection could be life threatening should be excluded from the study.