Dark circles under the eyes (raccoon eyes) are mostly due to melanin pigmentation. Your degree of pigment is obviously genetic. Hence, many people who have this problem are of Afro-American, Caribbean, Mediterranean or Hispanic descent.
A second cause is vascular congestion. This is an area containing many, small blood vessels. In some people, these are congested, causing a somewhat purple discoloration. Rubbing the area under the eyes certainly worsens the situation. Thus, people with atopic dermatitis (eczema) often are burdened with this discoloration.
Any dermatologist can tell you that a hallmark of eczema are these "allergic shiners." Rubbing can also be precipitated by an allergic contact dermatitis. Patch testing by your dermatologist might be able to elicit an allergy. Avoidance of that allergan would certainly help.
As we age, we lose collagen in general. This area, whose skin is thin to start off with, suffers the most noticeably. I am not talking about laxity here, although that is true too. The thinness of the skin makes the blue-brown pigmentation under the skin look even more apparent.
What to do about this problem? Fillers are probably the best solution as far as cost and convenience. Restylane is the better choice here since it is a little less mobile and remains where it is placed better. Also, it gives less of a blue tinge than its competitor Juvederm.
IPL may help. The vascular-pigment application at wavelengths between 530-600 would give you a good benefit as would a laser. As far as eye creams for this problem, there are as many of these as excuses for the Cubbies not going to the World Series.
Most of these products contain the following ingredients: Vitamin K, green tea, Vitamin C (make sure it has ferulic acid - Journal of the American Academy of Dermatology Sept 2008 - as this creates a much more stable product), licorice (yeah, that's licorice... the good tasting stuff), hydroquinone, and kojic acid. There are, of course, other helpful ingredients.
Brands I like, in no particular order:
RevaleSkin Eye Replenishing cream
SkinCeuticals Eye Gel
Neutrogena Radiance Boost Eye Cream
Olay's Definity
Hylexin (nervous about recommending the latter because they hype their product SO much.
