From: AKOSSOWSKY@TURBO.kean.edu
Subject: Re: SCI: VR AND DIVING
Date: 26 Nov 92 11:16:29 EST



Since I brought up the subject of diving masks, I'll quickly explain
it:

1. The 25% magnification is not psychological in any sense. It is
caused by the differences in refractive indicies of the water and the
air in the mask. It is the same effect as when you put a pencil in a
glass of water. The part under water looks 25% larger (and if you hold
the pencil at an angle, it looks split because of the same difference
in refraction).

2.  The tunnel vision does cause the magnification effect, the
magnification effect is the primary cause of the tunnel vision (I have
no editor, that was supposed to be "does NOT cause the mag effect,).

3.  One must NEVER wear goggles at depth, because the pressure would
compress the airspaces around the eyes and be very painfull and burst
most of the blood vessel, a condition called 'eye squeeze'.  A mask
encloses both eyes and the nose in one airspace so you can exhale
through your nose to equalize the pressure.

4. They make masks that are completely clear to help reduce the tunnel
vision but it is not as big a problem as you might think.

ApK