埼玉医科大学雑誌 第39巻 第2号 (2013年3月) 121-129頁 ◇論文(図表を含む全文)は，PDFファイルとなっています．
PDF (720 KB)
3D analysis of binocular eye movement during head tilt
Kazuki Sugizaki1)＊, Yasuo Koizumi2), Mio Iwamura2), Ryuichiro Araki3), Yasuhiro Kase1), Tetsuo Ikezono1), Toshiaki Yagi4)
1) Department of Otolaryngology, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
2) Department of Otolaryngology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan
3) Community Health Science Center, Saitama Medical University, 38 Morohongo, Moroyama, Iruma-gun, Saitama 350-0495, Japan
4) University of Human Environments, 6-2 Kamisanhonmatsu, Motojyuku, Okazaki, Aichi 444-3505, Japan
Ocular counter rolling (OCR) is one type of vestibulo-ocular reflex (VOR) originating in the otolith organ, and is one of the few effective tests of otolith function. The purpose of the present study was to assess the three-dimensional binocular eye movements that occur in response to the roll tilt. Furthermore, the study was intended to find out whether any asymmetry or disconjugacy of eye movements exists in 1 g environment.
Ten healthy subjects (6 males and 4 females) participated in this experiment. The subjects were tilted to the left or to the right on the naso-occipital axis up to 35 degrees (deg.). The eye movements were recorded and an analysis of these eye movements was performed using a video-oculographic method.
In torsional eye movement, there was counter-rolling of the eyes in response to head tilt. In terms of horizontal eye movement, the left eye deviated towards the right during left ear down (LED) tilt, and the right eye deviated towards the left during right ear down (RED) tilt. There was no asymmetry in the performance of horizontal, vertical or torsional eye movements. There was no disconjugacy in the vertical or torsional eye movements, and in the horizontal eye movements disconjugacy was observed in which the lowermost eye to the tilt deviated towards the opposite side.
In normal subjects in a 1 g environment, each of the three eye movements was symmetrical during head tilt. There was disconjugacy observed in the horizontal eye movements. The deviation of the lowermost eye towards the opposite relative to the tilt direction may be explained by the anatomical and/or physiological characteristics of the utricular nerve projection to the abducens nucleus.
J Saitama Medical University 2013; 39: 121-129
(Received August 17, 2012 / Accepted February 1, 2013)
Keywords: eye movements, ocular counter rolling, binocular, symmetry, disconjugacy
(C) 2013 The Medical Society of Saitama Medical University