What does sleep effects over the dark eye circle?

Sleeping Horizontally
 It is common to have dark circles under your eyes when you haven't slept enough, but interestingly, dark circles are not a direct result of tiredness. The most common cause of dark circles under the eyes is sleeping too horizontally. When you sleep horizontally, fluid from the eyes doesn't drain properly and will rest under the eye, causing bags under the eyes and shadows.

Pale and Tired
 If, after lack of sleep, your face is paler, this could be the reason for dark circles becoming apparent. The contrast of lighter skin against darker under eye circles could make them appear worse than they usually are. Also, pale, thin skin allows veins, puffiness and shadows to appear clearer underneath the eye, where skin is the most delicate.