The Culprit: That purply color is usually caused by dark veins showing through. Some people have genetically thinner and more see-through skin under their eyes, but skin also becomes increasingly translucent as collagen decreases with age. Dark circles can also form when the tiny channels inside veins under the eyes weaken over time; this causes the veins to dilate and the blood inside to pool. A lack of sleep can make blood vessels dilate, too.

Treatment Strategies: Use an eye cream to plump skin from the outside, which will make the veins underneath a little less visible. Choose one with subtle light-reflecting pigments to further brighten the area and gentle skin-lightening ingredients, such as kojic acid and vitamin K.

Makeup Strategies: Opt for a concealer with a yellow undertone, which neutralizes the purple tone of dark circles. Apply concealer with a thin makeup brush. Start at the inner corners, where the circles are darkest, and gently pat outward to where darkness fades, usually about halfway across the lower lids. Tap gently with a finger to blend. Avoid plum and blue eye shadows, which accentuate circles, and stick to neutral colors, such as taupe and mocha.

RS Picks

B.Kamins Therapeutic Eye Cream, $98
To Buy: www.bkamins.com.

Peter Thomas Roth Power K Eye Rescue, $100
To Buy: www.peterthomasroth.com.

Lancôme Effacernes Waterproof Undereye Concealer, $25.50
To Buy: www.lancome-usa.com.