In Chinese superstition, 左眼皮跳 (left eyelid twitching) means good luck is coming, while 右眼皮跳 (right eyelid twitching) means bad luck. The saying goes: 左眼跳财，右眼跳灾.
usage
眼皮底下 (under one's eyelid) is an idiom meaning 'right under one's nose', similar to English.
