🚀 go-pugleaf

There is a type of cataract called a "posterior subcapsular" cataract
that behaves the way you are describing.  The normal human lens is
sitting in a little "hammock" (the lens capsule) that is attached to
the cilliary muscles in an area called the zonules.  In a normal "old
age" cataract the lens is greying in the center and around the outside
edge, much like an old onion gets darker in the center and around its
edge.  In that type of cataract the patient goes through presbyopia as
he ages normally.  Things aren't to simple with PSC cataracts.  The PSC
cataract stiffens and greys the entire back surface of the lens, and
this can freeze your ability to accomodate.
Dick DeadEye wrote:
> 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=/