UV radiation exposure is frequently linked to true pigment behind the eyes. The sun's rays can trigger an increase in the synthesis of melanin resulting in dark patches under the skin.
Some people have deeper pigmentation beneath their eyes, which can make a black circle appear. While there is no proven aetiology for this disorder but hereditary factors may play a role.
Shadowing produced by complexion changes and lack of fullness associated with regular skin ageing causes dark circles around the eyes that seem hollow
The skin around your eyes loses its structure as you get older, making your eyes seem sunken. Which is created by a lack of fullness.
When your body doesn't get enough water, the skin around your eyes might look dull or sunken, comparable to a hollow appearance caused by volume loss