Shawkat F S, Harris C M, Taylor D S
Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Trust, London WC1 N 3JH, UK.
Br J Ophthalmol. 2001 Apr;85(4):428-31. doi: 10.1136/bjo.85.4.428.
To report five children with horizontal jerk nystagmus in whom eye movement recordings in the dark revealed a spontaneous reversal in the direction of the nystagmus beat. Three patients were blind in one eye and were diagnosed as having a manifest latent nystagmus (MLN), and two patients had strabismus and congenital nystagmus (CN).
Eye movements were recorded using DC electro-oculography with simultaneous video recording, including infrared recording in total darkness.
Four patients had decelerating velocity slow phase jerk nystagmus when recorded under natural lighting conditions; the fifth case had accelerating velocity and linear slow phase jerk nystagmus. Under absolute darkness, nystagmus reversed in direction of beat with a mixture of linear and decelerating velocity slow phase waveforms. One child with unilateral anophthalmos could wilfully reverse the beat direction of his nystagmus by trying to look with his blind eye in the light and dark.
These observations support the theory that LN/MLN beat direction is determined by the "presumed" viewing eye and may be consciously controlled. The spontaneous reversal of beat direction in the dark suggests eye dominance is predetermined. Eye movement recordings identified mixed nystagmus waveforms indicating that CN (accelerating velocity slow phases) and LN/MLN (linear/decelerating velocity slow phases) coexist in these subjects.
报告5例水平性眼球震颤患儿，其在黑暗环境中的眼动记录显示眼球震颤的方向出现自发反转。3例患儿单眼失明，被诊断为显性潜伏性眼球震颤（MLN），2例患儿患有斜视和先天性眼球震颤（CN）。
使用直流眼电图同时进行视频记录来记录眼动，包括在完全黑暗环境中的红外记录。
4例患儿在自然光照条件下记录时表现为慢相速度递减的眼球震颤；第5例表现为慢相速度递增和线性的眼球震颤。在绝对黑暗环境中，眼球震颤的方向发生反转，伴有线性和慢相速度递减波形的混合。1例单侧无眼球患儿能够通过在明、暗环境中尝试用其盲眼注视来故意反转眼球震颤的跳动方向。
这些观察结果支持以下理论，即潜伏性/显性潜伏性眼球震颤的跳动方向由“假定”注视眼决定，并且可能受意识控制。黑暗中跳动方向的自发反转表明眼优势是预先确定的。眼动记录识别出混合性眼球震颤波形，表明这些受试者中存在先天性眼球震颤（慢相速度递增）和潜伏性/显性潜伏性眼球震颤（线性/慢相速度递减）。
