FCPS Neurology
Clinical
Neurophysiology
fellow – AKUH, Pakistan
Phenomenology of abnormal ocular and eyelid movements may appear complex and difficult to describe at first but recognition of an overall pattern is helpful in characterization:
Ocular flutter comprises bursts of saccades in one plane, typically horizontal, during forward fixation. There are no intervals between saccades.
Opsoclonus is a continuous succession of multidirectional conjugate saccadic eye movements with no inter-saccadic interval, sometimes aptly called ‘saccadomania’.
Patients can manifest ocular flutter when developing or recovering from opsoclonus, and both disorders probably share pathophysiological mechanisms (In flutter, abnormal saccades are limited to horizontal plane).
Square wave jerks are abnormal conjugate saccades that take the eyes off a point of fixation, followed by a normal inter-saccadic interval (200 msec) and a corrective saccade back to the initial point.
Ocular tics are repetitive conjugate movements of eyeballs, usually up and outwards which are partially suppressible and associated with a sensory urge. These eyeball movements look similar overall on each occurrence. Consciousness is always preserved.
Oculogyric crisis involve intermittent tonic (sustained at peak) conjugate deviation of eyeballs usually upwards and outwards but can be in other directions or may even manifest as fixed central fixation. This is mostly seen as acute side effect of dopamine D-2 receptor blockers. Usually associated with an inner sense of fear.
Ocular myorhythima is a slow (<3 Hz) rhythmic vergence movements of the eyeballs in which they slowly move in and then move outwards (not crossing midline when going out). Seen almost exclusively in Whipple’s disease (oculomasticatory myorhythmia).
Eyelid Flicker is a slight vibration (4–6 Hz) of the eyelids without tonic spasm.
Eyelid Flutter are larger amplitude eyelid movements (3–4 Hz) resembling flapping of butterfly wings.
Eyelid Jerk is a sudden and quick tremor of eyelids, faster than a flutter (4–6 Hz) and accompanied by a brief tonic spasm of the eyelids
