PAVE (Parallactic Visual-Field Enhancement) System for Treatment of Chronic Visual Field Loss Due to Stroke, Traumatic Brain Injury, or Brain Surgery

Overview

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 the clinical outcomes from exposure to the PAVE therapy (test group) are statistically superior to those achieved with a placebo (control group). 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 for the test group when compared with the control group. The participants will visit the investigators office once per week for a minimum of eight weeks and a maximum of twenty four weeks and receive a therapy session. Every four weeks the participants visual field will be measured using kinetic perimetry. Every eight weeks the participant will complete the NEI-VFQ. 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 five 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 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 a random controlled trial with the test group receiving therapy with the PAVE software on the HMD. The control group will receive placebo treatment using the HMD. The placebo software will replace the patterns of PAVE with a different pattern. In both the control and test groups the patient is requested to focus on the central target during the session. The initial sample size will be n=15 for each group. Performance will be evaluated using a semiautomated kinetic perimeter (SKP) measurement derived from the Goldmann method. The study will be an adaptive design with interim data analysis and hypotheses evaluation performed every four weeks after the subjects have completed that week's therapy. Termination of therapy may occur four weeks after the interim data assessment. The decision to end the study will depend on the variance and the rate of change in the perimetry measures. If the rate of improvement of the test group appears constant, then the study will continue for at least another four weeks. If the variance between subjects is high, additional subjects may be recruited and added to the study to improve statistical power. The maximum duration of the study for an individual participant shall be 24 weeks of treatment and a 4 week follow-up for a total of 28 to 30 weeks. The goal will be to demonstrate a statistically significant difference in the improvement of the visual field between the test and control groups. Additional endpoints will include the percentage of test group patients showing improvement compared with the mean of the control group and subjective assessment of the subject's visual performance using the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ).