Eyeglasses have rx with od os add +2. 00 for bifocals . Want reading glasses ... what to change?

Question

eyeglasses have rx with od os add +2. 00 for bifocals . I want reading glasses ... The rx has sph ... cyl ... and axis . I want to order one pair of glasses for reading only. would I replace the sph or cyl with the add

Answer 1

An optical will make you reading glasses that are just for reading. They will add the +2.00 to your current sphere power. The Cyl and the Axis will stay the same, because they are just to correct for your astigmatism, if you have one. So, you can get over the counter glasses, but you seem to have that astigmatism, so they will never be as sharp as they could be. As to which power you should choose, say your sphere is +0.50, then choose +2.50 in readers, but if you are a -0.50, get +1.50. Good luck!

Answer 2

If your top power is for distance in the minus powers, it gets a bit complicated...

Write out your Rx here exactly as written , then someone in optical here can tell you what to do with it for the correct reading power.

I'll check back often.

______________________________________...

OK...because of the + cylinder it is more complicated...it has to be changed to - cyl first.

Ophthalmologists write Rx's in the + cyl form, but the whole industry works in the - cyl form..so it has to be converted.

Your Rx:

- 3.75 + 1.00 X 180

- 3.00 + 1.25 X 173

So after converting it, it becomes..

OD - 2.75 - 1.00 x 90

OS - 1.75 - 1.25 x 83

The axis has to be converted by 90 degrees when changing to the - cyl form....it is still the same Rx.

so, with the +2.00 added, your reading Rx would be as follows :

OD -0.75 -1.00 x 90

OS +0.25 -1.25 x 83

There you are !...notice there is a - on the right, and a + on the left...that's correct.

It may look strange to you...but believe me...that is how it works...

Answer 3

Over the counter readers DO NOT compensate for cylinder (cyl or astigmatism) correction.  If the cylinder correction is minimal, such as -0.25, no problem.

But to obtain OTC readers from your prescription, take your sphere power and add the ADD power to it.

Example...If your Rx is -3.00 -0.25 x52, add the +2.00 to the -3.00 which will give you a -1.00.  There are no OTC readers with a minus.

In  other words, your sphere power would have to start basically at -1.00 and have a range up to +1.50.

Hope this helps.