Sign of Plano power

[shubhendu]

Hii,
What is sign of a Plano power in prescription.
+0.00 or -0.00 or only 0.00/Plano
Which notation was correct & why.pls help.
Thanks in advance..

[juno]

I don't think it actually matters, everything is zero. At least here in the States, I have worked with various software that have accepted +0.00, 0.00, or -0.00, and some have auto-converted it into a different sign, but with no consistency. I will say that I think Plano or PL is only ok if you are actually hand-writing the Rx out, as most software doesn't like the non-numeric string. I think it's only going to matter if your specific software is popping up an error message, which may not be universal with other software. For instance, Davis Vision entry wants things in +0.00, but Spectera Vision removes + signs altogether in any part of the Rx

[KrystleClear]

I think this is why a lot of people will just write "Plano."

[juno]

I think this is why a lot of people will just write "Plano."

Sure, but that doesn't make any of them more technically correct or incorrect. You could get any of those four notations in as an optician (or doctor, for that matter) and still know exactly what you need to do for it, it would only be what your software demands of you as far as input goes. OP lists India as location, so I will heavily disclaim this as US-centric advice. I guess it's possible other countries could have specific legally-required protocol surrounding how plano must be written out on an Rx

[Uilleann]

Yep.

Zero = Zero = Zero

Sign [+/-] is irrelevant in practical terms. There is no "right or wrong" in any of those notations, nor is it wrong to use "plano" either.

[Barry Santini]

I respectfully disagree:

For almost all order entry systems and calculations, Plano is, by default, Plus-signed.

B

[Robert Martellaro]

I wrote it as Pl Sph so I didn't have to think too hard about all of the math it takes to make the lenses I used to fit.

But after a barrel of coffee I might enjoy reading something like this (pages 3-5) just to keep the cobwebs out of my inner spaces.

Robert

[Lensman11]

Great reading Robert. I had many heated conversations with opticians and Optometrists on this subject of Plano lenses and their associated oc. I still remember the answer I got that shut me down on this subject forever after. “Young man do you know what O.D. Stands for after my name, yes Optometric Doctor no was the it stands for Right (as in od and os ) I am always right and don’t forget it. I can’t tell you how many times people apply prentices rule when we have axis other than 90 and 180 and believe there is no prism created at the 180 because the power is Plano. It is Prentices rule not Prentices law because it is not always correct and goes not apply all the time.
The oc on low power lenses is hard to control because the lens is not parallel to the surfacing tool and prism is induced in the lapping process. It is a small amount but it has a huge effect on the oc in low power lenses. There are techniques to prevent this but they are rarely used as the standard equipment cannot be used.

[PRECISIONLAB]

my 2 cents...and as noted above

For notation purposes, handwritten typically is alpha so plano or pl sph.

For calculations purposes, numeric notation requires a sign of the integer as algebraic addition and subtraction is used for layout calculations such as the nominal lens formula for required backside curves.

So, the default + is simply a placeholder as required as coded in the software.

[Oculus Uterque]

I respectfully disagree:

For almost all order entry systems and calculations, Plano is, by default, Plus-signed.

B

Which might be because plano or ZERO is a positive number, which is in fact the correct answer to the OP.