Homonymous hemianopia (HH) patients report difficulties in avoiding collisions with other pedestrians. We evaluated pedestrian collision detection and avoidance behaviors in HH patients and healthy controls using a novel virtual reality (VR) walking with pedestrians, which enables natural walking behavior in an empty real-world corridor while viewing an immersive VR environment (shopping mall with colliding and other pedestrians) presented in a head-mounted display (HMD). Critically, it measures avoidance maneuvers in addition to collision detection. Colliding and non-colliding pedestrian scenarios were developed for Meta Quest 2 using Unity. Ten normal vision (NV) subjects and 12 HH subjects detected and avoided collisions with virtual approaching and overtaken pedestrians initialized at bearing angles of 20, 40, and 60 degrees, with planned time-to-collision of 6 seconds in each trial. HH subjects were less likely to detect and more likely to collide with pedestrians than NV, particularly for blind-side targets. Response times did not differ between groups but were faster for overtaken pedestrians. HH subjects also biased their head rotations toward the blind side and more after detection compared to before. Collision avoidance difficulties as reported by HH subjects, which clinical measures fail to capture, were recorded and analyzed with objective measures. These metrics may offer further insights into the underlying mechanisms driving collision avoidance behaviors. Our HMD-VR collision detection and avoidance paradigm enables natural walking behaviors and offers an affordable, objective assessment tool that may be adopted by clinicians for mobility enhancement and rehabilitation.

翻译：同向性偏盲（HH）患者报告在避免与其他行人碰撞方面存在困难。本研究采用一种新型虚拟现实（VR）行人行走模拟系统，评估了HH患者与健康对照组的行人碰撞检测与规避行为。该系统允许参与者在空置的真实走廊中进行自然行走，同时通过头戴式显示器（HMD）观察沉浸式VR环境（呈现带有碰撞风险行人及其他行人的商场场景）。其关键优势在于，除碰撞检测外，还能精确测量规避动作。基于Unity引擎为Meta Quest 2设备开发了包含碰撞与非碰撞场景的行人模拟程序。10名正常视力（NV）受试者与12名HH受试者需检测并规避虚拟环境中接近或被超越的行人，这些行人初始方位角分别为20、40和60度，每次试验中预设碰撞时间为6秒。结果显示，HH受试者检测到行人的概率更低，且发生碰撞的概率更高，尤其在盲侧目标上更为明显。两组响应时间无显著差异，但对被超越行人的响应更快。HH受试者头部旋转存在向盲侧偏斜的趋势，且在检测到行人后较检测前偏斜幅度更大。本研究通过客观测量记录并分析了HH患者主诉但临床检测难以捕捉的碰撞规避困难。这些量化指标可为揭示碰撞规避行为的内在机制提供新见解。本研究所开发的HMD-VR碰撞检测与规避范式支持自然行走行为，提供了一种经济、客观的评估工具，有望被临床工作者用于行动能力提升与康复训练。