Wolfberry, commercially called goji berry, is the common  name for the  fruit of two very closely related species: Lycium  barbarum. 
It is also known as Chinese wolfberry, mede berry, barbary matrimony vine, bocksdorn, Duke of Argyll's tea tree, Murali (in India), red medlar, or matrimony vine. Unrelated to the plant's geographic origin, the names Tibetan goji and Himalayan goji are in common use in the health food market for products from this plant.
Marketing literature for wolfberry products including several "goji  juices" suggest that wolfberry polysaccharides have  extensive biological effects and health benefits, although none of these  claims have been supported by peer-reviewed research.
Interestingly, now Dingbo "Daniel" Lin a researcher from Kansas State University, is studying wolfberries and their potential to improve damage to the  retina. His findings show that the fruit can lower the oxidative stress  that the eye undergoes as a result of type-2 diabetes.
Lin and his colleagues have found that wolfberries have high levels of  zeaxanthin, lutein, polysaccharides and polyphenolics, which have been  shown to improve vision, including the prevention of age-related macular  degeneration and diabetic retinopathy. 
By using type-2 diabetic mice, the researchers are studying the effects  of wolfberries on oxidative stress, one of the factors that occurs in  diabetic retinopathy.
"I would not say that wolfberries are a medicine, but they can be used as a dietary supplement to traditional treatments to improve vision," Lin said. "Wolfberries have high antioxidant activity and are very beneficial to protect against oxidative stress caused by environmental stimuli and genetic mutations."
Ref : http://www.k-state.edu/media/newsreleases/mar10/wolfberry33010.html