Fang Yu, Gill Christopher, Poletti Martina, Rucci Michele
Department of Psychological & Brain Sciences, Boston University, Boston, MA, USA.
Department of Neuroscience, University of Rochester, Rochester, NY, USA.
J Vis. 2018 Mar 1;18(3):18. doi: 10.1167/18.3.18.
Small saccades, known as microsaccades, occur frequently during fixation. Several recent studies have argued that a considerable fraction of these movements are present in the traces from one eye only. This claim contrasts with the findings of older reports, which concluded that microsaccades, like larger saccades, are virtually always binocular events. Here we examined the characteristics of small saccades by means of two of the most established high-resolution eye-tracking techniques available. A binocular Dual Purkinje Image eye-tracker was used to record eye movements while observers fixated, with their head immobilized, on markers displayed on a monitor. A specially designed eye-coil system was used to measure eye movements during normal head-free viewing, while subjects fixated on markers at various distances. Monocular microsaccades were virtually absent in both datasets. In the head-fixed data, not a single monocular microsaccade was observed. In the head-free data, only one event appeared to be monocular out of more than a thousand saccades. Monocular microsaccades do not seem to occur during normal head-free or head-immobilized fixation.
小扫视，即微扫视，在注视过程中频繁出现。最近的几项研究认为，这些运动中有相当一部分仅存在于单眼的眼动轨迹中。这一说法与早期报告的结果形成对比，早期报告得出结论，微扫视与较大的扫视一样，几乎总是双眼事件。在这里，我们通过两种最成熟的高分辨率眼动追踪技术来研究小扫视的特征。使用双目双浦肯野图像眼动仪在观察者头部固定、注视显示器上显示的标记时记录眼动。使用专门设计的眼线圈系统在正常无头部运动的观看过程中测量眼动，此时受试者注视不同距离的标记。在两个数据集中几乎都没有单眼微扫视。在头部固定的数据中，未观察到一个单眼微扫视。在无头部运动的数据中，在一千多次扫视中只有一次似乎是单眼的。在正常无头部运动或头部固定的注视过程中似乎不会出现单眼微扫视。
