抄録
The precise recording of human eye movements is important in both clinical and basic researches. Many techniqes have been used, but we have found the magnetic search coil method with a soft contact lens to be more convenient than the eye recording systems in common use. We devised a new search coil system based on Remmel's method. In our procedure, the horizontal and vertical fieled coild are driven at 50 and 75 Hz, respectively, by phase-locked square waves. The size of the frame which delivers the magnetic field is 30 cm in diameter. As a sensor eye coil, a newly designed soft contact lens is applied. The lens is made of silicone rubber and is 13.5 mm in diameter. It was tested in normal subjects, and there was no slipping from the eye and no corneal damage.
With this equipment, we studied the influence of eye-coil position on gains of both pursuit and saccadic eye movements in 10 normal subjects. The gains were unchanged when the eye-coil position moved within 5 cm in all directions and increased lineay when it moved more than 5 cm. With the use of these data, pursuit eye movements were investigated in an open loop condition. The scleral search coil system of measuring eye movements offers higher resolution, higher linearity, wider dynamic range, lower drift and lower noise, and is more stable than the conventional ENG. The advantage of our system were clearly demonstrated in velocity and acceleration tracings in an open loop condition.
In conclusion, our system was found to be ideal for the accurate recording of human eye movements.
