眼窩周囲における角膜網膜電位分布の研究

一側義眼のENG記録

抄録

The interpretation of ENG recordings in patients with an artificial eye has certain difficulties. The artificial eye moves in association with the intact eye, but the horizontal recording from the artificial eye is deflected in the opposite direction to the intact eye movement, synchronously and with minimum amplitude. This inverted horizontal deflection of ENG was first documented by Miles in 1939. However, the mechanism of this phenomenon remains to be elucidated. A subject with a left artificial eye and a right intact eye was selected for this study. Poly-graphic recordings were taken from several electrodes attached to the outer and inner canthus of the right eye, a, b; the nasal roof, c; and the inner and outer canthus of the left eye, d, e. The indifferent electrode was placed on the mastoid process. When the test subject was asked to gaze at a target 30° to the left, a showed -107.6μV; b, 124.3μV; c, 78.9μV; d, 57.2μV; e, 12.1μV. When he gazed 30° to the right, a showed 122.1μV; b -99.2μV; c, -63.3μV; d, -43.3μV; e, -29.5μV. Those data were well predicted by the electrical potential induced by movement of the intact eye alone. These results were compared with those of two normal subjects and two patients with oculomotor palsy. It was concluded that the synchronous inverted horizontal ENG recording from the artificial eye is caused by movements of the intact eye. It is assumed that the field of potential in one eye is always influenced by the corneoretinal potential of the other eye.