Digestion 2001;63:203-6.CloseRetinopathyDose: 150 mg dailyProanthocyanidins (OPCs), a group of flavonoids found in pine bark, grape seed, and other plant sources have been reported in preliminary French trials to help limit the progression of retinopathy.1, 2 In one controlled trial, 60% of people with diabetes taking 150 mg per day of OPCs from grape seed extract had no progression of retinopathy