Bilberry is a perennial shrub with dark purple fruit rich of anthocyanidins, it has been used as a dietary supplement for improving eyesight and relieving eye fatigue since 1965. It's reported that the  pilots of the Royal Air Force consumed bilberry as part of their breakfast during the World War II, to help them improve their vision for night flights.  The polyphenols found in bilberry have exceptionally powerful anti-oxidant potencies which help to relieve free radicals. Clinical research has also indicated that bilberry can improve vessel circulation thus promoting a reduction in cardiovascular diseases.