Fasting (and weird diets and anything that alters the osmolarity of your
blood) can change the optical qualities of the eye dramatically. It doesn't
improve your ability to see detail - you don't grow more photoreceptors -
but it's one of a few things that can significantly alter your refraction -
eg nearsighted or farsighted.

If you happen to be nearsighted and suddenly become less so, you'll declare
"it's a miracle."

OTOH, the same process would make a farsighted person's vision _worse_ and
they'd testify "that diet ruint mah vision!".

These effects tend to be temporary, but you can see how myths get started.

On the other hand, if you believe vitamins and micronutrients and fiber are
important in a healthy diet, it's hard to see how you could argue benefits
of doing without those for a week at a time.

There are some benefits to bilberry, as with any berry loaded with
antioxidants. But there are historical reasons why bilberry has a false
reputation for "improving vision."

Corrected visual acuity depends on how many photoreceptors you have, and how
smooth your optical surfaces are. We don't see bilberry making much
difference in actual acuity measurements.

-MT

It is doubtful you will experience any vision improvement unless there
is an underlying inflammation at a very low level which may be
affecting vision. Also note that many medicines can affect vision. It
is interesting to note that there are currently two large trials being
conducted to assess the use of these herbs and other antioxidants to
prevent macular degeneration or impede its progression. I suspect the
results will be positive because previous epidemiological studies have
suggested some dietary antioxidant compounds to confer protection for
the eyes.

The fasting is interesting, it may suggest something they were eating
was not good for their vision. Additionally, caloric restriction
results in a number of physiological changes that *may* help vision, in
particular increased protein turnover, slightly raised cortisol (will
inhibit inflammation), and improved antioxidant status. However, for
caloric restriction to work it is essential to maintain nutritional
status via supplements. For a fascinating article on caloric
restriction, track down Mark Mattson's article, "Starve me and watch my
brain run." Remember, the retina is the brain ... . Caloric restriction
together with good nutrition does wonderful things for the brain.

I wouldn't get too carried away with taking herbs etc to improve your
vision but there is unequivocally some benefit, particularly for those
at risk for eye related degenerative diseases, to seriously consider
taking something to protect their eyes. Don't wait til the problem
emerges, it's too late then, lifelong attention is required. Oh yes,
and get rid of trans fatty acids!

By the way, I've recently met two people who swear that taking an
antioxidant formula specifically designed for eye protection have
halted their macular degeneration and improved their vision, so they
claim. I can understand the halting bit, not so sure about the
improving bit.