Three-dimenional eye movement analyi of uperior oblique myokymia

Purpoe To confirm the idea that ole contraction of the uperior oblique mucle caue attack of uperior oblique myokymia (OM). Deign Obervational cae report. Method A 43-year-old man preented with epiodic monocular ocillatory eye movement. Three-dimenional eye movement were recorded uing the magnetic earch coil ytem and analyzed a rotation vector. The attack of OM conited of intorional, depreive, and abductive fat phae and their exponential decaying low phae. Reult Average direction of rotation axi for the fat phae while fixating traight ahead wa 51.5 ± 5.4 degree from depreion axi in vertical-torional plane, 78.7 ± 4.4 degree from abduction axi in horizontal-torional plane, and 76.3 ± 4.3 degree from abduction axi in horizontal-vertical plane (±D, n = 50). Time contant of low phae were le than 0.1 econd. Concluion Quantitative three-dimenional analyi of OM directly confirmed that the fat phae of OM attack were induced by the ole contraction of the uperior oblique mucle.