The Schepens Eye Research Institute, Boston, MA 02114, USA.
JAMA Ophthalmol. 2013 Mar;131(3):303-9. doi: 10.1001/jamaophthalmol.2013.1443.
To determine how central field loss (CFL) affects reaction time to pedestrians and to test the hypothesis that scotomas lateral to the preferred retinal locus will delay detection of hazards approaching from that side.
Participants with binocular CFL (scotoma diameter, 7°-25°; visual acuity, 0.3-1.0 logMAR) using lateral preferred retinal fixation loci and matched controls with normal vision drove in a simulator for approximately 1½ hours per session for 2 sessions a week apart. Participants responded to frequent virtual pedestrians who appeared on either the left or right sides and approached the participant's lane on a collision trajectory that, therefore, caused them to remain in approximately the same area of the visual field.
The study included 11 individuals with CFL and 11 controls with normal vision. The CFL participants had more detection failures for pedestrians who appeared in areas of visual field loss than did controls in corresponding areas (6.4% vs 0.2%). Furthermore, the CFL participants reacted more slowly to pedestrians in blind than nonscotomatous areas (4.28 vs 2.43 seconds, P < .001) and overall had more late and missed responses than controls (29% vs 3%, P < .001). Scotoma size and contrast sensitivity predicted outcomes in blind and seeing areas, respectively. Visual acuity was not correlated with response measures.
In addition to causing visual acuity and contrast sensitivity loss, the central scotoma per se delayed hazard detection even though small eye movements could potentially compensate for the loss. Responses in nonscotomatous areas were also delayed, although to a lesser extent, possibly because of the eccentricity of fixation. Our findings will help practitioners advise patients with CFL about specific difficulties they may face when driving.
确定中央视野损失（CFL）如何影响行人的反应时间，并验证以下假设，即视网膜优势侧旁的暗点会延迟对来自该侧的危险的察觉。
使用侧向视网膜优势固定点的双眼 CFL（暗点直径 7°-25°；视力 0.3-1.0 logMAR）的参与者和具有正常视力的匹配对照者在模拟器中每周进行 2 次、每次约 1 个半小时的驾驶。参与者对经常出现的虚拟行人做出反应，这些行人出现在左侧或右侧，并且沿着与参与者车道碰撞的轨迹接近，因此使他们保持在视野的大致相同区域内。
该研究包括 11 名 CFL 参与者和 11 名具有正常视力的对照者。CFL 参与者在视野丧失区域中出现的行人的检测失败率高于相应区域中的对照者（6.4%比 0.2%）。此外，CFL 参与者在盲区内对行人的反应速度比非暗点区内慢（4.28 比 2.43 秒，P<.001），并且总体上比对照者的迟发和漏发反应更多（29%比 3%，P<.001）。暗点大小和对比敏感度分别预测了盲区内和可看见区内的结果。视力与反应测量无关。
除了导致视力和对比敏感度丧失之外，中央暗点本身也会延迟危险的察觉，即使小眼球运动可能潜在地补偿损失。在非暗点区域内的反应也会延迟，尽管程度较轻，这可能是由于注视点的偏心度。我们的发现将有助于从业者为 CFL 患者提供有关他们在驾驶时可能面临的特定困难的建议。
