Affection of Visual Field Right-Side Bias Due to Head Mounted Displays on Bisection Tests

-A Study of Healthy Subjects-

抄録

【Background/Purpose】

 Left-sided USN patients continually look to their right, but are often not conscious of doing so. Moreover, this leads to a vicious cycle that makes it difficult for a patient to direct his or her attention to the left. However, there is no clear understanding of how a right-side bias in a patient’s visual field affects their spatial perception.The purpose of this study was to verify the effect of a visual field bias to the left in spatial perception in healthy young subjects.

【Methods or Cases】

 We recruited 40 right-handed healthy adults. The subjects were divided into four groups which were devided by using hand and by visual field direction.. An HMD with an attached webcam was fitted to the subjects’ heads. The camera angle was centered for the groups with such that the a centered visual field was also centered and biased horizontally to the right by 10° (the Yaw angle) for the groups with a right-biased visual field group. Each of the four groups underwent the line bisection tests across four combinations of variables, using a stick or mouse to point at a touch panel located 60 or 120 cm away from the subject.

【Results】

 At the result, regardless of the hand used, when the index finger or stick was used (reaching condition), the line bisection point was displaced significantly to the left of center. Additionally, a major left-displaced trend was observed in the short distance tests that did not use in which tools were not used compared with the long distance tests that used tools in which they were used.

【Discussion/Conclusion】

 This finding may have been a result of the amount of practice (or sufficient experience) coordinating hand and eye movements in the condition where participants used their dominant hand and reached with their own arm and not a stick (i.e., visual motion adaptation).

【Ethical consideration】

This investigation conducted according to the principles expressed in the Declaration of Helsinki. Each participant provided a signed informed consent form.