Hi! Skin around eyes is the thinnest and that is why poor blood circulation in that particular area appears more prominently in the form of blue/black circles. The best treatment to treat dark circles is to increase oxygen circulation in your body with the help of exercises, yoga. Taking break between hectic work schedule and splashing your eyes with cold water 2-3 times a day is helpful. Drink plenty of water throughout the day, have a balanced diet, eat more iron and zinc containing foods like dates, nuts and dry fruits. Many topical creams that contain kojic acid helps to reduce dark circles but they should be taken after consulting a good dermatologist only. Some latest treatments like light therapy, skin resurfacing and injectable fillers give faster and long lasting results, but before you choose one it's important to determine the cause. As for the dark patches they could be melasma due to hormonal imbalances.