VR-HMD Eye Tracker in Active Visual Field Testing

Abstract

Visual field defects (VFDs) is difficult to recognize by most patients because of the filling-in mechanism in the human brain. The current visual field test displays light sources within the range of the effective visual field and takes the responses from the patient after recognizing this light stimulus. Since, these responses are determined subjectively by the patient, the resulted measure may be less reliable. This method may take more than 30 minutes, requiring the patient to fix his gaze and head where it may give a physical burden in the patient. In this study, we propose an active visual field testing (AVFT) based on a high-speed virtual reality head-mounted display (VR-HMD) eye tracker which enables to increase the testing reliability and to reduce the physical burden during the test. Our tracker runs up to 240Hz allowing the measurement of rapid eye movement to precisely detect visual fixation and saccades which provide essential elements to evaluate defects in the visual field. The characteristics of visual fixation and saccades are utilized to confirm when each stimulus is recognized by the patient during the test. Our experiment shows that each test can be conducted in 5 minutes.