Sentence:  Without moving your head, move your gaze upward to look at twelve <WSD>o'clock</WSD>. Now look down at six <WSD>o'clock</WSD>. Repeat three times, then blink several times, and rest with your eyes closed. 
Meaning of the word marked with <WSD> tags:  In conjunction with a numeral, indicates the direction, relative to the speaker or a vehicle, especially an aircraft, corresponding to the direction the hour hand is pointing at the time corresponding to the numeral, with twelve representing directly ahead and three being to the right.