A study of search coil positions in the magnetic field

Abstract

Eye monements were recorded by a scleral search coilmagnetic field system. We studied how the coil fitted the eyes, and how the amplitude changed when the coils moved in the magnetic field.
1. The amplitudes of eye movements of 30° which were recorded by a scleral coil-magnetic field system were equal to the amplitudes of 30° of the coil movement at the same position as the eyes in the magnetic field. Therefore, there seemed to be no slipping of the coils on the eyes. However, when the coils became old, or frequently used, sometimes the fitting of the coils on the eyes was very loose.
2. The more the coil moved forwards or backwards, the smaller were the amplitudes of the horizontal and vertical coil movements. The more the coil moved upwards or downwards, the smaller were the amplitudes of the horizontal coil movements, however the vertical coil movements became larger. The more the coil moved to the right, or to the left, from center of the magnetic field, the larger were the amplitudes of the horizontal coil movements, however the vertical coil monements became smaller.
3. The same amplitudes of coil movements as of eye movements recorded by coils at the center of the magnetic field occurred when the coils moved from the center of the magnetic field; 10cm to the right or to the left, 5cm upwards, 10cm downwards and 25cm backwards.