Help with Intermediate RX

[misstara007]

Can anyone remind me on transposing this Rx:

True Rx
+1.50 +1.75 x 2
+1.50 +2.00 x 170

+2.50 Add

For Computer the OD says to use a +1.00

Is this the right rx?

+2.50 +1.75 x 2
+2.50 +2.00 x 170

+2.50 Add (????) or +1.00 Add

Gues Im just mostly confused on the add... Should I use +2.50 or +1.00?

Thanks- Just havent done this in a while :)

[CME4SPECS]

+1 for inter. +2.50 for near.

[Uncle Fester]

Is this the right rx?

+2.50 +1.75 x 2
+2.50 +2.00 x 170

Yes

[kgcopley]

the rx should read intermediate +2.50+1.75x2 od +2.50+1.75x170 os with a +1.50added for reading so if a bifocal you will have a +1.50 add

[misstara007]

So for FT 28
+2.50 +1.75 x2
+2.50 +2.00 x170

Add- ?

[bob_f_aboc]

So for FT 28
+2.50 +1.75 x2
+2.50 +2.00 x170

Add- ?

the rx should read intermediate
+2.50+1.75x2 od
+2.50+1.75x170 os with a
+1.50 added for reading so if a bifocal you will have a +1.50 add

The answer is right in front of you.

[CME4SPECS]

So for FT 28
+2.50 +1.75 x2
+2.50 +2.00 x170

Add- ?

miss, the total add is 2.50, you've used 1.00 already so you have 1.50 left for the bifocal.

[misstara007]

:cheers: Got it. Thanks

[tmorse]

For starters, I can't understand why your computer came up with only +1.00 Add for Computer use.

Regular intermediate is normally about 50% of Bifocal Add and is good for
distance of about 30-40inches. 50% of +2.50 is +1.25, not +1.00.
But a computer is located about 22-24 inches away, and usually requires 60% (or even 66%) of the +2.50 Add.
60% of +2.50 is +1.50, not +1.00

So I believe adding +1.00 to Sphere is incorrect, as +1.00 is only 40% of the +2.50 Add.

So add +1.50 to the OD and OS Sphere, and leave amounts of cyl and axis the same. Since you used +1.50 for the computer intermediate, the balance of the original +2.50 ADD is +1.00. If making a bifocal, it's Add Power for reading would be this left over Add+1.00. :cheers:

[Senorwes1]

According to most optical textbooks,
If you want a Computer Rx ONLY (with no Bifocal Add for near), the Rx should be:
OD +2.75 +1.75 X 002 (Take 1/2 the add power and add it to the sphere power)
OS +2.75 +2.00 X 170

If you want a Computer Rx (with a FT 28 Bifocal Add), the Rx should be:
OD +2.75 +1.75 X 002 Add +1.25
OS +2.75 +2.00 X 170

Now, if the Dr. specifies something different, then make them as the Rx is written.
As you have written here, I would assume the Dr. wanted you to add +1.50 to the sphere power and make the ADD POWER +1.00,
so the Rx would be:
OD +3.00 +1.75 X 002 Add +1.00
OS +3.00 +2.00 X 170

Hope we haven't all confused you with so many different suggestions. Good luck.

[drk]

Take out some +1.25 trial lenses and sit at a computer. You'll see it's a little constraining.

I like +1.00, FWIW!