• Two patients with botulin ophthalmoplegia had rapid quivering eye motions during attempts to refixate laterally placed objects; these abnormal eye movements occurred in conjunction with a disjunctive limitation of range of eye movements. Oculographic examination showed that the quivering motions were composed of multiple hypometric saccades, many of which had subnormal and stuttering velocities. By blocking acetylcholine release into myoneural junctions, botulin toxin seems to limit the duration of saccadic burst innervation reaching ocular muscle.
Hedges TR, Jones A, Stark L, Hoyt WF. Botulin OphthalmoplegiaClinical and Oculographic Observations. Arch Ophthalmol. 1983;101(2):211-213. doi:10.1001/archopht.1983.01040010213005