Eye exam - near/far vision

When you get an exam for glasses, does the test give the doctor one
number for near vision, and one number for far vision?

If so, how does the doctor then decide what to write for Cylinder, if
the two are different?

On Sep 2, 10:13 am, "Mike Tyner" <mty...@mindspring.com> wrote:
> "Richard Fangnail" <richardfangn...@excite.com> wrote
>
> > When you get an exam for glasses, does the test give the doctor one
> > number for near vision, and one number for far vision?
>
> > If so, how does the doctor then decide what to write for Cylinder, if
> > the two are different?
>
> Cylinder is assumed to be exactly the same for near and far.
>
> "Cylinder" describes the steepest and flattest meridians.
>
> When there is a "+2.00 add," both meridians are changed by +2.00.
>
> -MT

When they make bifocals, what do they use for the two different parts?
That is, how do you write an Rx for bifocals? From what you say,
Cylinder would be the same for near and far.

"Richard Fangnail" <(E-Mail Removed)> wrote in message
news:86efcaed-f2ab-4f9e-a385-(E-Mail Removed)...
> When they make bifocals, what do they use for the two different parts?
> That is, how do you write an Rx for bifocals? From what you say,
> Cylinder would be the same for near and far.

He is wrong. The Rx has the distance vision (typically measured at 20 ft)
and there is an "add" power specification that only applies to the bottom
reading area of the lens (so the reading area is the sum of the distance
plus the add power).