I think what they will eventually find out is multiple forms of vitamin A. Probably at least one form from animals and another form from beta carotene.

My reason is this. They know that carotenoids (including beta carotene) greatly improve the eyes. They know that vitamin A greatly improve the eyes.

If carotenoids are not being converted to Vitamin A - then they must not be measuring the right form of vitamin A. Perhaps they are measuring the animal version of vitmain A and not the plant version.

The other problem about studies regarding beta carotene and vitamin A are that researchers that show positive studies usually use natural beta carotene, mix in other carotenoids and antioxidants.

I think that most researchers that want to show bad news - use synthetic beta carotene all by itself.