PROCEDURE:  ,This tracing was obtained utilizing silver chloride biopotential electrodes placed at the medial and lateral canthi at both eyes and on the superior and inferior orbital margins of the left eye along a vertical line drawn through the middle of the pupil in the neutral forward gaze. 
PROCEDURE : , This tracing was obtained utilizing silver chloride biopotential electrodes placed at the medial and lateral canthi at both eyes and on the superior and inferior orbital margins of the left eye along a vertical line drawn through the middle of the pupil in the neutral forward gaze .