Re: Fwd: [rlhymers-watcher] Glasses, Drugs and Color Perception

From: herownsourgelatine <dlinden_at_jhmi.edu_at_hypermail.org>
Date: Sun, 03 Jun 2007 14:00:12 -0000

--- In OliveStarlightOrchestra_at_yahoogroups.com, Bark of Delight <barkofdelight@...>
wrote:
>
>
> --- Joy McCann <joy.mccann_at_...> wrote:
>
> > So do they really help? Or am I simply being
> > visually obsessive-compulsive
> > by putting the glasses on?
> > ....
> > Perhaps I'm nuts. Or maybe I need some LSD.
>
>
> Yes to all the above.
>
> DJQ to elaborate presently.
>
> Bark!
>
Here's the deal. If you are looking at a uniform field of a single color, it won't matter if
you have your glasses on or off-- your perception of that color will be the same. However,
if you are looking at a natural scene in which color varies a lot across the visual field, then
having corrected versus blurry vision will have a big impact. Essentially, when your vision
is defocused, then a single cone or small group of cones (the color sensing cell type in
your retina) will be receiving light from multiple adjacent points in your visual field. If
these points have different colors, then those colors will be blended as the image blurs.
You can see this effect another way by taking a slide or video projector and twiddling the
focus knob...

hosg
Received on 2007-06-03 07:00:20