In the past couple of years presbyopia has become acutely apparent
(I just turned 40, ugh!) and now a backsided cataract (meaning its
on the inside of the lens, instead of the outside), due to previous
uveitis.  Even at the beginning of the year, my vision was still
20/20 correctedl; it has suddenly dropped in the past few months to
20/50, even corrected, but does improve to 20/20-20/25 while looking
through "pinhole glasses", so both of my eyedoctors (including a
retinologist) are confident it is just the cataract.
It doesn't seem to be the stereotypical "haze" type cataract, or even
blurry presbyopia, but rather like you're looking through binoculars
that are focused near the end extreme, where there is "ghosting" (like
looking through a double-paned window) and faces beyond 20-30 feet have
a mushy blur to them and in general has a somewhat watery-eyed
(as if crying) view.

(BTW, the vitreous is detatched in that eye, and other eye I'm blind in
from similar uveitis, 10 years after this eye!)

The thing is, the main problem seems to be that my focus seems to
have "frozen":  If I look at a streetlight in the distance at night,
I see a triangle of 3-4 lights (now seems to be morphing more into
a blurry circle), and if I hold my finger out to arms lentgh and
try to focus on it as I bring it close in, right up to my nose (so
that I'm crosseyed), the focus doesn't budge!!
I've also tried focusing on a poster on the wall, and I've found
that the FARTHEST in focus (in the same way that "bifocals" have
a sharp dropoff point) seems to be about 18" without glasses, 12"
through the bifocal part and 23" through the distance part--i.e.,
about 1.5-2 feet!!
Could the main problem (compounded by the cataract) be that the
focus is "frozen"--extreme presbyopia?
Is there a name for this?
I had a similar question about "dual focus" last year at about this
time:

   http://groups.google.com/group/sci.med.vision/msg/9b9daa68c98e9b62

Needless to say, things have gotten worse.  P=/