P3D Re: Re Wearing glasses, P3D Re: Pulfrich Effect

[abram klooswyk <abram.klooswyk@xxxxxx>]

P3D Re Wearing glasses, P3D Re: Pulfrich Effect

Dan Shelley, Boris Starosta, George Themelis wrote on wearing and not
wearing glasses. 
Jim Crowell used to comment on issues like this. 

My first reaction would be: what glasses are you talking about?
Glasses come in several different forms and are prescribed for a number
of different conditions. So the issue is complex.

Myopes with minus 5 Diopter (like me) wouldn't be helped much by taking
off there glasses in projection! But they certainly can do parallel free 
viewing without glasses, in fact easier than non-myopes. 
I call this my built-in stereo viewer. In fact, by the time I will have 
lost all accommodation my eyes will be better for free viewing than for
normal vision :-).  (My astigmatism is small, as is the difference 
between my left and right eye.)

Boris obviously has a small amount of astigmatism. In this condition the
strength as well as the axis of the correcting lens is significant. In
some cases strong 3D distortion effects arise in people who wear these 
lenses for the first time, this is a *geometrical* effect which occurs 
not only with moving objects (or a moving subject), and it is not a 
Pulfrich effect, but the distortion can be disturbing in moving (I also
have tried this myself). 

Glasses are also prescribed for latent amounts of squint and
wall-eyedness.
With several types of glasses *also* color depth effects occur, as 
described by Boris (but let chromostereopsis out off the discussion 
for some time :-)).

Abram Klooswyk


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