Unfortunately, it's not as simple as a linear calculation. BUT, the
rule of thumb is as follows:
Distance prescription = 20' to infinity
Computer prescription = 24-36"
Reading prescription = 12-24"
In your case your ADD (reading correction) is a +2.00, which means
that an additional +2.00 diopters (for a total prescription of -/25 +
2.00 = +1.75) gives you clear vision at 12-24". For a computer
prescription, it would be half of that extra strength...+1.00.
BUT, there's an easier way...and especially since your regular
prescription is so extremely slight at only -0.25. Just go to your
nearest WalMart or discount store, and try on some reading glasses.
Try them, with your eyes, at various distances...experimentally
determine which gives you the vision you require at the distance you
require.
And, while we're at it, be aware that yours is a somewhat special
case. DISCUSS YOUR REQUIREMENTS WITH YOUR DOCTOR...standard reading
distance, while useful for most, may be irrelevant to you. Instead,
clearly seeing a column wheel at a distance of 6" or less may be of
paramount importance.
Ask him also about monovision. You're already using it...regular
vision in one eye, and magnified through a loupe in the other. My own
loupe clips on the side of my glasses.
Monovision is not a common option, especially at the normal
dispensaries, but there's no reason that it wouldn't work for you.
-- Chuck Knight
On Fri, Oct 30, 2009 at 10:53 PM, clocker <[email protected]> wrote:
>
> Hi all.
> I have another question.
>
> While I was thinking about what Chuck and Ed had to say about my last
> questions I got thinking about task specific glasses for close work.
>
> I'm sure glasses that are specifically designated to suit viewing ones
> computer screen would be very popular. I'm developing a few ideas of
> my own on what might be handy.
>
> How do you specify the changes, from whatever the default is, in
> relation to ones prescription? Or does the vendor do that for you if
> you provide a verbal confirmation of the desired distance?
>
> I'm thinking specifically about a desired reading distance, but not
> exclusively.
> Ian
>
>
> >
>
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