Graduated compression socks or stockings are specifically designed to prevent occurrence or recurrence of venous disorders such as edema related to varicose veins, thombophlebitis and deep venous thrombosis.  They are tightest at the ankle, and become less constrictive moving up the leg, hence the term "graduated".  This pressure gradient helps to compress surface veins and optimize the return of blood to the heart against gravity.
Our clinic no longer carries compression hosiery and socks.