Beautiful Eyes

The skin under the eyes is the thinnest on the body. The many blood vessels in this area can show through the delicate skin, contributing to the appearance of dark under-eye circles, especially if the vessels become dilated.
Dark under-eye circles begin in the capillaries, the tiny blood vessels that web the delicate skin around the eyes. The capillaries are so small that red blood cells sometimes have to line up, single file, to get through. Frequently, red blood cells get lost and wander into the surrounding skin. This isn't a problem - it happens all the time - and your body has a mechanism to mop up these escapees. Enzymes in your body break down the red blood cells, including their hemoglobin. When hemoglobin is broken down, its remaining components have a dark blue-black color. Just like a bruise. So your dark under-eye circles are actually caused by leaky capillaries. It's quite possible that capillaries all over your body are leaking small amounts of blood all the time.But the reason dark under-eye circles are so apparent is this: the skin around the eyes is some of the thinnest, most delicate skin of your entire body. The capillaries are much closer to the surface of the skin there. Many people's skin is not only thinner around the eyes, but also more translucent. The combination of capillaries near the skin's surface and translucent skin makes this discoloration much more apparent. And that's why you have those dark under-eye circles staring back at you in the mirror.