I'm 29 years old, myopic with astigmatism, and correctable to 20/20.  
I wear glasses about 70% of the time and contacts the rest of the
time.

Lately I've been noticing a weird sensation with my vision...  If I
dart my eyes around quickly I notice almost a smearing effect for a
split second as my eyes refocus.  This seems particularly compounded
if I glance back and forth between a bright light (like a flourescent
one) and an unlit background.  It also happens in both eyes, and they
feel like they are burning and worn out towards the end of the day.

I recently visited my optometrist and was told this is pretty common
for computer users (I spend 8 hrs/day average on the computer).  She
gave me a script for "computer glasses" which basically are my current
script knocked down a little bit, apparently to help my eyes relax.  
The do seems to help, but its been several days and my eyes are still
doing this.

I am starting to wonder if there is some other kind of thing going on
here...  Are any of these symptoms of some crazy eye disease, or is
this just typical for computer users?  If so, is it worth doing some
extra digging around for eye exercises?  Thanks in advance!!