Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.
Invest Ophthalmol Vis Sci. 2014 Mar 13;55(3):1540-8. doi: 10.1167/iovs.13-12748.
Using a driving simulator, we examined the effects of homonymous hemianopia (HH) on head scanning behaviors at intersections and evaluated the role of inadequate head scanning in detection failures.
Fourteen people with complete HH and without cognitive decline or visual neglect and 12 normally sighted (NV) current drivers participated. They drove in an urban environment following predetermined routes, which included multiple intersections. Head scanning behaviors were quantified at T-intersections (n = 32) with a stop or yield sign. Participants also performed a pedestrian detection task. The relationship between head scanning and detection was examined at 10 intersections.
For HH drivers, the first scan was more likely to be toward the blind than the seeing hemifield. They also made a greater proportion of head scans overall to the blind side than did the NV drivers to the corresponding side (P = 0.003). However, head scan magnitudes of HH drivers were smaller than those of the NV group (P < 0.001). Drivers with HH had impaired detection of blind-side pedestrians due either to not scanning in the direction of the pedestrian or to an insufficient scan magnitude (left HH detected only 46% and right HH 8% at the extreme left and right of the intersection, respectively).
Drivers with HH demonstrated compensatory head scan patterns, but not scan magnitudes. Inadequate scanning resulted in blind-side detection failures, which might place HH drivers at increased risk for collisions at intersections. Scanning training tailored to specific problem areas identified in this study might be beneficial.
使用驾驶模拟器，我们研究了同视性偏盲（HH）对视场中头部扫描行为的影响，并评估了头部扫描不足在检测失败中的作用。
14 名完全性 HH 患者和 12 名认知功能正常的视力正常（NV）驾驶员参与了本研究。他们在城市环境中按照预定路线行驶，其中包括多个交叉口。在 T 型交叉口（有停车或让行标志的交叉口）（n = 32）量化了头部扫描行为。参与者还执行了行人检测任务。在 10 个交叉口处，检查了头部扫描与检测之间的关系。
对于 HH 驾驶员，第一次扫描更有可能朝向盲视侧。与 NV 驾驶员相比，他们总体上对盲视侧进行了更多的头部扫描（P = 0.003）。然而，HH 驾驶员的头部扫描幅度小于 NV 组（P < 0.001）。HH 驾驶员对盲侧行人的检测受损，要么是因为没有向行人所在的方向扫描，要么是因为扫描幅度不足（左 HH 在交叉口的最左侧仅检测到 46%，右 HH 在交叉口的最右侧仅检测到 8%）。
HH 驾驶员表现出代偿性的头部扫描模式，但扫描幅度不足。扫描不足导致盲侧检测失败，这可能使 HH 驾驶员在交叉口发生碰撞的风险增加。针对本研究中确定的特定问题区域进行的扫描训练可能会有所帮助。
