One eye weak astigmatism, one eye strong: what do I do for differentials?

Dear fellow endmyopians :slight_smile:

I have been reading a lot on the forum and the blog lately and still have not come to a conclusion to which prescription my first diffs should have. I currently have the following prescription:
L: -2,25, cyl -0,75 (146)
R: -2,25, cyl -1,75 (170)
The problem I have in evaluating which way to go is: should I start reducing cyl or sph first? The left cyl is neglectable in my vision, but the right isn’t. If I start with sph, I would leave the cyl the way it is and not cut out the left cyl, to not confuse the eyes too much. If I start with cyl, I would have to find the proper amount of reduction. Should I rather reduce on both eyes, or start with the weaker first? It’s very weird, so I would be very thankful for your various opinions.

Helpful postings and info for me were especially Kent’s story and also Aaron’s story, both from the podcast and the forum, and also info from Lajos. So, in any case, I’m gonna be careful in not reducing too much. I also have an optometrist who supports me in going this way, and also uses diffs for near-work e.g., but he warned me that reducing too much sph might end up in worsening the cyl, so yeah, slowly and steadily.

On another note: I think I will also buy a test lens kit to answer this question, but the only proper one I found for my condition is about 150€/170$. So I was also thinking: wouldn’t it make sense to have a place where endmyopians can resell or give away test lens kits they don’t use anymore? I’m based in Germany, so American sellers will have too high shipping costs.

Let the cylinder be the same for your first pairs of differentals and nomalized and when you have made some reduction then you can start to work on reducing your cylinders. That is how I have understood . I have -1 in cylinder and have kept that prescribtion the same. I started out on sphere -2 both eye and will now start use normazied -1.50. I have had -1.75 for most of the summer. I think I might start to work on my cylinder when I am down on -1 or 1-25 or so. Good luck!

When in doubt, keep things simple, which means change as little as possible. Tolerance for dropping cylinder varies, and you’re going to have to do the steps to reduce complexity for the eye with more cylinder anyway, may as well save the better eye until that step and have fewer changes now.

Thanks! In your understanding, @Marigold, if you had two different cylinders, would you first try and equalize them or work on both at the same time?
I guess it makes sense to start with the spherical, to unburden the eye from the muscular strain.

That’s actually a good point of view. So I won’t reduce cyl in the better eye, that’s what I thought as well, but neither in the weaker. I guess I’m gonna start with the spherical. Thanks!

Jake always suggests general sph reduction first as it’s simpler on the brain, to get the hang of reducing.

having said that, he also suggests an INITIAL drop in cylinder for differentials as you don’t need so much astigmatism correction up close

in my experience, you can get away with a BIT of equalisation but don’t try to change that 1 D difference in one step! I have 0.25 D cyl difference between the eyes and equalised that for my first diffs.
but reduction didn’t go so easy on the eyes (strain)

so I would start with a mild reduction on both eyes for close-up of up to 0.5D with maybe a small step of 0.25D reduction extra on the stronger cyl to move a little bit in the direction of equalisation

but that’s just my opinion, based on my personal experience

ah OK you already read some stuff from me :wink:

I got one too and used it at the start quite a lot but then didn’t use it again since then

it can be useful but you can also get away without it. The problem is that in some cases strain shows up after hours or even days and you can’t hold the test lens in front of your face that long :wink: or wear the test frames that long. BUt yeah, for complex prescriptions like yours (sph, cyl and unequal eyes) it is more useful than for simple prescriptions

I think unless you find a used one in germany you’ll have to go via ebay and order one from China but the price is still in the range you posted.

to make it more complex I think how much reduction your eye can take also depends on which is your dominant eye. your dominant eye might get used more and hence get strained more by a reduction than your non-dominant eye…

I am far too inexperienced to answer that question. You better listen to the more experient fellows here. But it seems to be more difficult to reduce cyl than sphere from what I have understood.

https://endmyopia.org/pro-topic-how-to-reduce-prescription-complexity/

1 Like