Re: Simple Prescription Question


ok ... now I think I get it; even knowing better, I haven't really been
properly accounting for the difference in distance from reading material I
typically experience ... do people really consistently read stuff at 16" ??
well, guess you have settle in on something or the other .. unless you want
to keep a variety of glasses around

what we need is auto-zoom lenses ... maybe one of these days nanotechnology
will give us microprocessors embedded in lenses; AI will figure out the
focal distance and trigger changes in refractive power something along the
lines of "Transitions" changing the level of tint ... not in my lifetime I
would not think ... we'll probably just fix the eye
itself instead ...

<<
My own radical opinion is that educated and licensed opticians should be
able to make these adjustments, since those without the need for distance
correction are free to choose any power they like, from +1.00 to +3.25 at
any wal-mart. But alas in most states, licensing boards will consider it
an actionable offense for an optician to provide the same options to
ametropes (people who need glasses for distance.) To me it's inconceivable
that you have no right to ask for a +0.75 pair of SV.


I'd have to go along with this one, being of a libertarian bent ... just so
long as the opticians are making these judgments in consultation with the
patient

thanks ...

BW



"Mike Tyner" <mtyner@xxxxxxxxxxxxxx> wrote in message
news:S6KdnQMiyflnnGHbnZ2dnUVZ_j2dnZ2d@xxxxxxxxxxxxxxx

"Barrie Wilson" <bwilson@xxxxxxxxxxx> wrote

but Mike, just to clarify, if I went down to the local "eye shop" and
handed them my Rx and said I wanted a pair of SV reading glasses made,
what would they likely do?

Licensed opticians will feel obligated to fill the rx as written. The way
it's written, "SV reading glasses" will be made at +1.25 in each eye.
Other than frame quality and some refinements, these would be
indistinguishable from decent drugstore glasses.

The distance rx of -1.25 means you see pretty well at (1/1.25=0.8m=) 30
inches with no glasses. This obvious benefit for reading is why nature
made you nearsighted in the first place. You see better at 30 inches than
someone who isn't nearsighted, because your eyes already have "built-in"
reading glasses just as someone else would get from +1.25. So you only
need +1.25 more to add up to +250, which will be clear at (1/2.50=0.4m=)
16".

So whether you "need" reading glasses depends on how well you can cope
with that 30-inch "natural" working distance, eg pushing your monitor back
and holding your newspaper out. But if you can see your monitor without
glasses now, you probably won't be able to see it from the same position
with a pair of +1.25 glasses. That's OK if you get "half-eye" frames so
you can look over them.

The 16" assumption is traditional, but these days it only works for
laptops, watchmakers and cross-stitiching.

In your situation, working distance is everything. So for a 16" working
distance, you need +125 more near power than nature gave you. For an 18"
WD, you need +100. For 20", you need +0.75. Drugstores don't sell +0.75
but you can probably find them on the internet. For 30", you take your
glasses off.

would they use the "calculated" +1.25? (based on the -1.25 add 2.50, both
eyes) I just had an eye exam and the numbers on the Rx are what they are
... are they even allowed to adjust it to +1.00 when an OD has said
otherwise ? or is there more to the arithmetic?

My own radical opinion is that educated and licensed opticians should be
able to make these adjustments, since those without the need for distance
correction are free to choose any power they like, from +1.00 to +3.25 at
any wal-mart. But alas in most states, licensing boards will consider it
an actionable offense for an optician to provide the same options to
ametropes (people who need glasses for distance.) To me it's inconceivable
that you have no right to ask for a +0.75 pair of SV.

But if you want something custom, you may have to make your doctor
understand what you want and get a written script. It's often difficult
with younger doctors who haven't experienced the intricacies of presbyopia
themselves. :) Your situation is simple enough you could write your own
script and have some made on the Internet.

Perhaps you were advising on the assumption that I was just going down to
the drug store to buy a pair of "readers" ?? which is perhaps what I
should do?

Well you certainly could. I recommended you think about +100 rather than
+125, but it all depends on where you sit, where is your monitor, where do
you read, and such. You can try the two in a drugstore and you'll find
that one is clear about two inches closer than the other. You'll probably
find +1.25 a little confining. DON'T base it on "print size." Pick some
small print and move your head in and out to see what _distance_ works
best.

You could benefit from a drugstore pair that is ridiculously strong, like
+200 or +250, to put away in the medicine cabinet or tacklebox, for
untying knots and taking out splinters, things you hold 10 inches away.

The biggest problem with SV glasses is they're SV - only clear at certain
distances. You can approximate what you need with this pair or that, but
you wind up with an assortment of powers and they disappear right before
you need them.

My favorite fix, in your situation, is a custom progressive with
about -0.50 in the top and a +1.50 add, depending on how long your arms
are. These are "indoor" glasses only, because they contain only the range
of powers that are useful in a small room, cubicle, or workshop.

-MT, OD




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