Many diagnostic tools, which record eye movement, are available for diagnosis and treatment of the patients with impaired eye movement. Most of these tools cannot record directly the eye movement but record electrical analog signal developed when eyeball moves through electrode attached on skin or sclera. Because they need a fixation device, they may bring a patient discomfort. It is well known that digital recording device is not interfered by external noise signal and that its reproducibility is acceptable. We have developed a noninvasive, direct, and precise technique for recording eye movement and verified its reproducibility. We video-taped the horizontal and vertical eye movement and processed the captured images digitally using a image analysis program. the result showed the frequency energy of eye movement in the range within 6Hz and at 10 or 11Hz. The eye movement was observed more clearly after filtering the low frequency energy by inverse Fourier transformation. The reproducibility for measurements of total variability were as follows; vertical displacement measurements, 1.21%; horizontal displacement measurements, 0.68%. In conclusion, this new technique is easy and comfortable to examiner and patient. Its reproducibility was acceptable. Thus it may served as a substitute of conventional tools for recording eye movement.
Diagnosis ; Electrodes ; Eye Movements* ; Fourier Analysis ; Humans ; Noise ; Sclera ; Skin