Jim, these types of visual perceptual problems are very difficult, if
not impossible, to diagnose (much less treat).
It could be related to a depth perception deficiency but
that should be easily shown with the various tests we have.
So I don't think there are any easy answers that would
explain your vision disturbances.

frank

Well, perhaps "normal" brains might do this. Mine certainly doesn't.

I'd say when the object appeared to get smaller, it was becasue your
brain switched _out_ of "glasses mode". With your lenses on, it had to
mentally magnify your retinal images to make them fit the space you
felt around you. Take the lenses off, and this compensation was no
longer needed. But we were taught the world didn't just change size
(except in fairy tales) so it was only in unusual circumstances that
you became conscious of the change happening.

One of my responses to wearing negative lenses through most of my
childhood was to learn to disconnect the perceived size of an object
from its distance. I stopped directly experiencing the change in
perceived size as I moved toward and away from things. I learned to
rely only on perspective and relative motion to judge distance. The
experience of moving toward an object was like "dollying" a camera
toward it while "zooming" the lens wider - leaving the object the same
visual size. (Or in another way of thinking, part of me left my body
and stayed back away from the object while the other part approached
it.)

Of course I knew objects should appear larger as they got closer, and
if you had asked me I would have said they did, but I didn't
experience it directly. After many years without lenses, I'm finally
beginning to learn to re-connect the link between size and distance.
When I remember to mentally switch it on (sort-of like learning to
move a long forgotten muscle) the difference in how the world appears
to work is shocking.

I remember disconnecting the link when I was maybe nine years old, as
a way of adapting to lenses that were otherwise far too painful to
wear. I keep intending to find time to study how the optometric
profession thinks adaptation is supposed to work. Apparently most
people can tolerate the size changes their lenses impose, with only an
occasional artifact like Dan describes.

But as I mentioned, if you had asked me earlier, I would have said I
saw objects get bigger as I got nearer. I wonder how many other
lens-adapted people see such size changes mentally but not in the
direct, vivid, visual way I'm re-learning to see them...  

Loren