Re: II vs. X

[P3D Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 8:55 PM -0700 4/21/97, P3D Dr. George A. Themelis wrote:
>This is not 2 vs. 10 but Parallel vs. Cross viewing.
>
>Gabriel want to take a poll as to which is easier for most people.
>I can see both points.  In order to parallel view you need first to relax
>your eyes, and make them diverge towards infinity (daydreaming, etc.)  Once
>the images are locked (fused) then the muscles are called to focus the
>image.  In order to cross view you need to strain the eyes as if you are
>looking closer.  Many people might find it easier to strain their eyes
>instead of making them relax.

There was a discussion about this a few months back.  The relationship
between accomodation (lens focus) & convergence generally isn't calibrated
perfectly accurately.  Some people (exophores) tend to converge too little,
i.e. at a greater distance than where they're focused, & they tend to find
wall-eyed viewing easier; others (esophores) tend to converge too near &
tend to find cross-eyed viewing easier.  Both kinds of phoria can be easily
detected by an optometrist & are thought to contribute to eyestrain...

That's probably only a partial explanation, however, & I don't know that
anyone's ever taken a large-sample survey...

I prefer wall-eyed, myself.

-Jim C.

----------------------
Jim Crowell
Division of Biology
216-76
Caltech
Pasadena, CA
(818) 395-8337
jim@xxxxxxxxxxxxxxx



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