This story has been around for a while now, but I just
recently learned about it. It's the niftiest thing I've
heard in quite a while.
Executive summary: For the vast majority of colorblind
people, there now exist special "sunglasses" that make
the full range of colors visible.
It turns out that contrary to conventional wisdom, the
vast majority of "colorblind" people have three sets
of cones. The third set is not missing; it's just
shifted so that it overlaps far too much with its
neighbor.
The fun thing is, this is fixable! Suppose you have
a sharp notch filter that cuts out the region of
overlap, leaving only the wings where the two response
curves are reasonably distinct.
Apparently the biology had been known for years, but
the people who knew it didn't put two and two together.
They didn't think of it as a fixable problem. The
eventual solution involved some serendipity.
Pedagogical remark: This makes a great answer for
students who ask what physics is good for. It turns
out that there are still lots of unsolved problems
out there, and lots of nifty solutions waiting to be
invented. By and large, nowadays all the best work
is interdisciplinary. You need to know physics /and/
something else.
-- Without physics, you could never solve the color-
blindness problem.
-- With "only" physics, you could never solve the
colorblindness problem.