Improved Search Coil Method for Measuring Eye Movements

描述(由申请者提供)：研究人员将开发一种新的设备，用于精确和方便地测量眼睛运动。该装置基于现有和广泛使用的有线巩膜搜索线圈技术，在眼睛上放置一个带有小线圈的环形隐形眼镜，其方向由外部磁场在线圈中感应的电流的大小确定。新设备在眼睛上使用了类似的巩膜隐形眼镜，但新的隐形眼镜没有从眼圈到相关电子设备的电线。信号在眼睛线圈中感应，并由眼睛附近的发送器/接收器从眼睛线圈检测。根据接收到的信号确定透镜和线圈的方向。现有的原型系统是新系统进一步开发的基础，新系统将沿着以下方向进行：1)评估现有系统的工程设计选择；2)制造嵌入适当线圈的新隐形眼镜；3)扩展系统以测量扭转眼球运动以及水平和垂直运动；4)包装为可供受试者佩戴的独立系统；5)通过对眼睛和镜头运动的视频分析来评估性能。这种新方法保留了传统有线线圈分辨率高、精度高、运动范围大和完全三维定向测量的优点。传统系统的最大缺点是从眼圈到信号处理电子设备的导线。通过消除这些电线，产生了几个非常显著的优势。主体舒适性大大增加，因为从眼睛引出的外部电线经常刺激眼皮，并导致令人讨厌的睫毛刺激。可以进行更大范围的实验，因为将头放置在外部磁场中的限制变得更少；无头实验，如涉及运动和自我产生的运动的实验变得更加实用。也许最重要的是，避免了外部布线的断裂(当前系统中最常见的故障来源)。“无线”测量系统将为研究和临床社区带来巨大的好处。特别是，前庭和动眼患者对新线圈的耐受性应该比现有线圈好得多，这样可以更容易、更方便地在更大一部分人群中记录准确的眼球运动，对他们来说，传统线圈往往令人生畏和不舒服。

DESCRIPTION (provided by applicant): The investigators will develop a new device for the precise and convenient measurement of eye movements. The device is based on the existing and widely used wired scleral search coil technique, in which an annular contact lens with a small coil of wire is placed on the eye, and its orientation determined from the magnitude of the current induced in the coil by external magnetic fields. The new device uses a similar scleral contact lens on the eye, but the new lens has no wires leading from the eye coil to the associated electronics. Signals are induced in the eye coil, and detected from the eye coil, by a transmitter/receiver near the eye. The orientation of the lens and coil is determined from the received signal. An existing prototype system is the basis for further development of the new system, which will proceed along the following lines: 1) assessment of engineering design options with the existing system; 2) fabrication of new contact lenses with the appropriate coils embedded; 3) extension of the system to measure torsional eye movements as well as horizontal and vertical; 4) packaging as a stand-alone system that can be worn by the subject; 5) assessment of performance by video analysis of eye and lens motion. This new method retains the conventional wired coil's benefits of high resolution and accuracy, large range of movement, and complete three-dimensional measurement of orientation. The largest drawback of the conventional system is the wires that lead from the eye coils to the signal processing electronics. By eliminating these wires, several very significant advantages result. Subject comfort is greatly increased, as the external wiring leading from the eye often irritates the eyelid and causes annoying stimulation of the eyelashes. A greater range of experiments can be performed, since the placement of the head within the external magnetic fields becomes less restrictive; head-free experiments, such as those involving locomotion and self-generated movements become much more practical. Perhaps most importantly, breakage of the external wiring (the most common source of failure in current systems) is avoided. The "wireless" measurement system will be of tremendous benefit to both the research and the clinical communities. In particular, vestibular and oculomotor patients should tolerate the new coils much better than existing ones, allowing easier and more convenient recording of precise eye movements in a larger segment of this population, for whom the conventional coils are often intimidating and uncomfortable.