Wow! Thanks for that piece of the puzzle! I did not know zinc was needed to convert beta-carotene to retinal! I had come to the conclusion that I was genetically unable to convert beta-carotene to Vitamin A but now it looks like it could be just another side-effect of my allergies using up all the damn zinc! And yes I do have eye issues...like a dry eye issue...when there is cold dry air which causes me allergies...all goes away when the temp rises above 32. Do your eye issues go away as the weather improves?