How do shadows and bags appear under the eyes ?
a) The bags:
When the walls of the blood capillaries become altered, their tonicity diminishes. A water leakage can be observed which makes the eye swell, and an oedema or bag appears in the neighbouring tissue.
b) The shadows:
When the walls of the blood capillaries become altered, their tonicity diminishes. A leakage and a stasis of blood pigments can be observed in the neighbouring tissue together with a reduction in the speed of the circulation of blood in the capillaries. The shadows, which are situated in the furrows under the lower eyelid, take on a purple hue, revealing the blood pigments that have accumulated under the skin. Progressively, the blood pigments which have infiltrated become oxidized, bringing about the variation in the colour of the shadows.