Equalizing 0.25D difference

Hey there,
I am sorry but I couldn’t find an answer to my question in the other threads!

So my left eye needs -1.75D (says the endmyopia calculator) and my right eye only -1.5D.

When I want to equalize (I also have slight astigmatism on the left eye: -0.25 cylinder and 3 Axis) should I reduce the Left to -1.5D or put the right eye higher to -1.75D. I am wondering also because of my astigmatism but I guess that is not so dramatic and I should reduce the Left to -1.5D.
Somehow I remember I read somewhere that these low Axis and CYL numbers can be left out but only if they are not too big.

Am I right?
I hope you understand what I wrote because I am German!

Thank you and excuse this newbe question but Its urgent! :slight_smile:

2 Likes

Usually, if its your 1st reduction dont equalise.
Do 2-3 reductions before you equalise.
This is just for training and getting used to reducing.
Equalising it a bit more difficult.

Secondly 0.25 diopter difference is considered a “natural” difference. So even if youre R 0.25D and L 0.00D, its not of a big concern.

So my reccomendation would be one of two ways.

  1. If this is your first reduction I would wait 2-3 reductions before trying to equalise.
  2. Dont worry about equalising because its “natural”.
4 Likes

Thank you it helps me a lot. Have a great week Alex!

-0.25 cyl can usually be dropped easily, especially if these are the measurements for differentials. If these are for your normalised then most probably you are not using any corrections for close up work.
This 0.25 cyl simply means that if your left eye needs -1.75D then a part of your left eye could do with an extra eighth of a diopter correction. But as the lenses comes in quarter diopters, you would be just corrected at a certain angle. Axis is the angle, if you need cyl = additional partial correction within the eye, then you’ll need it at position 3 degrees. You don’t reduce or increase the axis. You only reduce the diopters - the sph and cyl values.

Otherwise I agree with @Alexbreedon1111 start with normal drops to get into the practice.

Good luck.

2 Likes

Okay cool, thanks so much! I will definetly will go into depth with my research in the future.

Yes i wanna order my first normalized.

I dont know if I understood correctly, you say, I can “delete” the CYL, but the axis shouldnt be changed. Only the SPH and CYL?
I read in the wiki: " When reducing cylinder value, you should never change the axis value" But if I dont have any CYL, I dont need any Axis anymore, or not?

1 Like

Delete cyl = drop cyl = not add astigmatism correction
These all mean the same.

When you order glasses, there will be the following 3 fields to fill in: sph, cyl, axis. If you don’t want astigmatism / cyl correction, you enter the diopter in the sph field and leave the other 2 fields blank or enter zero.
0.25 cyl can only be reduced to zero, there’s nothing lower. 0.25 cyl is so low that you most probably won’t even notice the difference in vision, or just in certain low light situations.

(In comparison if someone else had let’s say -1.5 astigmatism at axis 3, they could reduce it first to -1.0 at axis 3, then to -0.5 at axis 3 and finally to zero. Or could go at -0.25 cyl steps, too, but the axis would stay 3)

Yes. Axis is the direction of the cyl correction. If you have no cyl correction, you have no direction of the cyl correction, so no axis.