Implementation of a Subjective Visual Vertical and Horizontal Testing System Using Virtual Reality

Subjective visual vertical (SVV) and subjective visual horizontal (SVH) tests can be used to evaluate the perception of verticality and horizontality, respectively, and can aid the diagnosis of otolith dysfunction in clinical practice. In this study, SVV and SVH screen version tests are implemented using virtual reality (VR) equipment; the proposed test method promotes a more immersive feeling for the subject while using a simple equipment configuration and possessing excellent mobility. To verify the performance of the proposed VR-based SVV and SVH tests, a reliable comparison was made between the traditional screen-based SVV and SVH tests and the proposed method, based on 30 healthy subjects. The average results of our experimental tests on the VR-based binocular SVV and SVH equipment were −0.15° ± 1.74 and 0.60° ± 1.18, respectively. The proposed VR-based method satisfies the normal tolerance for horizontal or vertical lines, i.e., a ±3° error, as defined in previous studies, and it can be used to replace existing test methods.