Re: Simple Prescription Question


"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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