OCULAR MICROTREMOR MEASUREMENT SYSTEM - DESIGN AND PERFORMANCE

The frequency of ocular microtremor (OMT) is related to the functional status of the brain stem, and thus OMT may be useful in the diagnosis and management of brain stem disorders. The paper discusses the desig n of an OMT measurement system and reports quantitative specifications for three portable systems. All systems use a piezo-electric element as the transducer, which measures the displacement of the sclera durin g eye rotations. The systems differ in the manner in which the signal is recorded. All systems can detect eye movements corresponding to dis placements of the sclera ranging from 12 to over 3000 nm. The frequenc y responses of all systems are flat (< 2 dB deviation from peak respon se) between 20 and 150 Hz. The phase response shows deviations (< pi) at the extremes of this range, but qualitative comparison of input and measured signals demonstrates that phase distortion is not excessive. Thus all systems are acceptable for clinical studies involving OMT.