The mysterious Blue Sensitive Eye Cones

On Thu, 24 Jul 2003 01:28:35 GMT, (Stuart Levy) wrote:

Very interesting -- does this mean our eyes have *four* (or more?) types
of cones? Or is this an additional sensitivity peak in one of the
three I'd already heard of, and if so, which?

No, it just means there are at least 5 different pigments that have been
identified. In most people, the neural wiring is set up for one rod population
and 3 cone populations. So the effect of the UV sensitive pigment is essentially
the same as an existing pigment having a second absorption peak. Most people are
still trichromats.

The thing is, the retinoid pigments are apparently quite variable, and there may
be a significant range of actual function in the population. But the neurology
is much more uniform. How any of this affects individual color perception is
hard to assess. My point in the context of the original post was simply that an
aphakic eye does have some significant UV sensitivity. AFAIK this doesn't extend
to the ability to identify UV as anything other than blue, however.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com