Can anyone advise me about blueberries and whether or not they are used for varicose veins?

Nothing Confirmed. Blueberries can boost blood flow and are rich in vitamin c. They also repair damaged proteins in the blood vessel walls and promote the overall health of the vascular system. On top of that, blueberries are a good source of both insoluble fiber and soluble fiber such as pectin.
No proof. Blueberries have vitamin c which enhances the anti-inflammatory effect of bioflavonoids. These are supposed to improve vein elasticity and increase blood flow in the legs, thus preventing or eliminating varicose veins. Blueberries also have antioxidants called anthocyanins which are supposed to help strengthen the vessel integrity and thus reduce varicose veins. None of this is proven.
No proof. Blueberries contain antioxidants called anthocyanins which are supposed to help strengthen the vessel integrity and help vein health. Blueberries also have vitamin c which enhances the anti-inflammatory effect of bioflavonoids. These are supposed to improve vein elasticity and increase blood flow in the legs . There is no medical research that proves that these factors prevent varicose veins.
No. I have never heard of using blueberries for varicose veins. Generally speaking these veins can be treated medically or surgically. Blueberries is not an option, imho.
Blueberries. blueberries are rich in bioflavonoids which aid strength to blood vessel walls so the may be helpful but not the ultimate choice.