Do not know much about fatigue, don’t have a problem with it, But I do know a lot about vitamins, minerals, supplements and herbals. Twenty years of research fifty years using them. The eyes and the adrenals use and need vitamin C the most. Any shortage to the adrenals can throw the whole system out of whack. Health problems, sugar, injuries, stress, etc. draws vitamin C away from the adrenals and eyes gets cataracts. ??????
Love this internet page 'Vitamin C, Insulin, And Why Tigers Don’t Get Scurvy'.