Can a holistic practitioner really reads the whites of you're eyes for a basis of overall health?

Not quite. I'm not sure, but i wonder if you might be thinking of iridology? This focuses on the colored part of the eye, the iris, rather than the white part of your eye (sclera). Iridologists say that because there are so many nerve endings in the iris, it can reveal tendencies to illness. A 1979 jama article could draw no conclusions about this. For additional info, see: http://www.Iridologyassn.Org.