Under Eye Circles

What are under eye circles?

Under-eye circles or dark circles are a common cosmetic concern globally (R). In an Indian study, their prevalence was estimated to be as high as 31% (R). They affect more women than men (R), and women also seem to have more pronounced dark circles (R). They are typically first noticed during puberty or early adulthood (R, R), and become more common and more severe up until age 60, when their intensity diminishes (R).

Under-eye circles can be classified into different types based on their colour, the visibility of the blood vessels under the skin, whether they are structural, and whether they have a hereditary component. Pigmented dark circles have a brown hue and are sometimes associated with solar lentigines, freckles, melasma or other forms of pigmentation. Vascular dark circles have a blue, pink or purple hue, and prominent blood vessels that become more visible when the skin is stretched. Structural dark circles are shadows cast by the anatomical structure of the face such as hollows or tear troughs under the eyes, and disappear when illuminated directly. Constitutional dark circles appear as brown to black pigmentation over the lower eyelids, and are associated with a strong family history (R, R, R, R).

The type of under-eye circles is associated with one's race and skin type, with vascular dark circles being more frequent among the Chinese and those with darker skin (types IV and V), whereas constitutional dark circles and tear troughs are more common among Malays and Indians (R, R, R).

What causes under-eye circles?

The biggest risk factor for dark circles is often one's family history (R, R, R), since genetics have an influence on facial bone structure, the amount of melanin and haemoglobin, the number and size of the capillaries under the eyes, and the thickness of the skin under the eyes, all of which affect the appearance of dark circles (R, R, R). Interestingly, anaemia due to a deficiency in iron is also associated with dark circles, with some anaemic patients reporting improvements in their dark circles after their anaemia was treated (R). This may be because lower oxygen saturation of the blood under the eyes contributes to facial pallor, which makes dark circles more prominent (R, R).

Under-eye circles can also be exacerbated by lifestyle factors such as stress and a lack of sleep. An unhealthy diet that causes inflammation and glycation may also hasten the skin's pigmentation process (R, R).

Because there are many possible causes that can lead to under-eye circles, the underlying causes for each affected individual should be identified first in order to select the appropriate treatment (R, R, R).

How are under eye circles measured?

Under-eye circles can be clinically assessed and scored by comparing them visually against a scale containing photographs to illustrate the different grades of severity (R, R). They can also be evaluated objectively using instruments like a colorimeter or chromameter to measure the amount of melanin in the skin and the degree of erythema of the skin under the eyes, or through image analysis of photographs (R, R).