Measurement with fiber optics of nystagmus eye movements
Ernesto Suaste-Gómez, Lorenzo S. Leija, Humberto J. Sossa-Azuela · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1995
Usually for study and to analyze the nystagmus eye movements is used a non invasive method for eye movements with an infrared limbus reflection technique, based on an IR-LED emitter and photo diodes detectors, also using a scleral search coil in a magnetic field and digital image processing. We use a new technique, silica-based fiber optic system with rod lens that consist in two pairs, a pair for horizontal eye movements and another for vertical eye movements and a circular array in order to detect torsional nystagmus. This fiber optics bundle was made on a spectacle mounted differential reflectivity device. The electrical signals detected are introduced to two instrumentation amplifiers (horizontal and vertical), an amplifier-multiplex for torsional nystagmus and we use an interface of eight channels A/D connected to the PC. The software is developed to analyze: position, velocity, acceleration, cross correlation, FFT based processing for frequency analysis and power spectral density determination. The results obtained were in these areas: nystagmus, eye tracking (X - Y), saccadic eye movements related to visual stimulus on a visual perimeter then compared with the IR-LED and photo transistors techniques and application for disabled.