High Astigmatism, low myopia

Read a lot on astigmatism, myopia, glasses and science. I’ve read too much and now eyesight topic is like an unfinished puzzle that needs some guidance. Here we go.
I have high astigmatism both eyes
OD SPH 0.5 CYL 3.0
OS SPH 0.25 CYL 3.0
This is my 20/20 glasses indoor whith good lighting (results got midday)
Bot eyes i’ve removed 0.5 cyl and added .25 sph in order to reduce cylinder
Planning now to get normalized with only .50 cyl reduction .
Do I need for differentials to keep the SPH and only reduce CYL or I’d better use test lens kit to find most confortable diopters for close up until i see slight blur ?

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Hi, I noticed nobody ever replied. Im curious on your progress. If you have a moment could add an update?

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Ok. Long story short. For a very long time was wearing -1.75 and -1.5. Then i tried equalising then i tried lowering. Couldnt see any progress. And that i did for at least 2 years. Dont know where the problem is.

So now i am not wearing any glasses at all because after wearing any glasses all day at the end of day i feel my eye are getting tired and am afraidbto damage them any further.

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me too i’m desperate. i do not know what to do anymore. i’m dancing in circles

I’ll be watching this too because I’ll probably need it in about 3-6 months!

I started out at:
OD SPH -1.25 CYL -4.25
OS SPH -2.00 CYL -4.25

Current Normalized (20/25) is at:
OD SPH -0.5 CYL -2.75
OS SPH -0.75 CYL -2.75

My next set will be:
OD SPH -0.5 CYL -2.50
OS SPH -0.5 CYL -2.50

I’m really starting to fly by the seat of my pants, I have gotten so far without increasing my sph, I think my plan will be to settle in on equalized -0.5 sph and then when it’s comfortable go up to -0.75sph and do a long slow descent on my cyls. My diffs will only have cyl by that point. In the case that I start getting ciliary spasm, I may need to reduce sph on the norms and try adding a little plus (+)sph to diffs, but who knows if I’ll do it until the time comes and I consider it a last resort as it’s relatively unknown territory.

I also plan an using the best lenses with anti-glare from this point forward as my test lens kit has indicated that “Operation: Rugby to Basketball” could produce some horrendous glaring.

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When I asked zenni for some plano prisms, it would not allow it. I had to have at least a quarter diopter of sphere in anything. But the plus option seems a good one.

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Wow, good to know, thx.

Hi,

One question, for a prescription everytime you add for example -0.5 cyl you have to add 0.25 sphere right? to compensate the spherical power the cyl adds…

So if you have for example 2sph, -4cyl, the spherical equivalent is 0, so in that case you don´t have myopia/hyperopia, you have “pure” astigmatism, is that right?
Because you naturally have the circle of least confusion in the center, but two separate images due to the astigmatism. If you add or remove spherical power, you simply de-center these two images respect the retina.

I came to this conclusion after watching these videos:



Am I right?

Sounds about right… it seems to me it would be simpler to think of the cylinder correction as a +/- thing. I think +2D sph, -4D cyl means it’s +2D on one axis, and -2D on the other. Could also be specified as -2D sph + 4D cyl (on the perpendicular axis).

But an even simpler way that it could have been described is 0 sph +/- 2D cyl (Which is just what you are saying.) The axis is slightly less intuitive this way, though. Doing it this way, you don’t have to think about “spherical equivalents” - the average, and therefore the spherical equivalent, is always 0. (Well… to be fair, you’ve already factored it in by convering it into this form…)

Good, so for example if you have:
+2 SPH, -4 CYL, and you want to make a reduction of 0.5 CYL, you have to also reduce 0.25 of SPH, resulting in +1.75 SPH, -3.5 CYL, in order to keep the spherical equivalent the same (or in other words, to compensate the sphere that the cyl was giving you). Later if you realize you can reduce the sphere you can do it, but that is independent (or in other words, is another variable of the problem).

So, if this is correct, in those cases where the spherical equivalent is equal to zero (pure astigmatism), when trying to reduce cyl, I’m not sure if the rule of trading cyl for sphere is useful, because if you modify the spherical equivalent you are de-centering the circle of least confusion, which I don´t see that can enhance your vision, am I right?

I think you might be talking at crossed purposes slightly. (Though you’ve almost certainly thought more about it than I have.) I think when you talk about trading cylinder for sphere, you’re talking about just the cylinder part. ie in your example, the -4D part. So by definition, you cannot have a “spherical equivalent of zero”. (Except for the trivial case that cylinder was just 0.25D) Here, the spherical equivalent (aka avergage) of -4D cylinder is -2D spherical. And then you combine this -2D equivalent with the original +2D spherical, and getting net 0 overall.

It seems to make sense, if your overall prescription is (in the terminology I introduced above) 0 +/- 2D, then then next step is 0 +/- 1.75D. You wouldn’t want to introduce a net spherical term.

With the “trading cylinder for sphere”, I was referring to the technique I have read in Endmyopia when someone wants in the next round to reduce CYL, to add SPH to compensate the blur to be able to deal better with the astigmatism. I think that if in your prescription you have a spherical equivalent of zero, it doesn´t make sense to mess with the spherical equivalent.

I think we agree, but it’s just a detail of terminology/conventions.

Even if you are not “net zero speherical”, when you trade cyl for sph you are not “messing with” the spherical equivalent: you are preserving it.

Ok thanks, another question,

Suppose there is a quite imbalanced 20/20 prescription, for example:
SPH; CYL; AXIS
OD: +1.50; - 3.00; 108
OS: +0.25; -0.5; 60

And the diffs could be:
OD: +0.75; - 1.50; 108
OS: 0.0; 0.0; 60

In this case, is it advisable for the left eye to try a differential prescription like this?:
OS: -0.25; +0.50; 60
To keep enhancing the left, and to create similar level of blur challenge between right and left?

Thanks!

Sorry, I couldn’t offer any kind of practical advice on the best lenses to try. (I’m very new here.) What you’d need is a guru (or someone who has already been through a similar process).

Just noticed


which looks like another case of low myopia / high astigmatism. You might want to compare notes …?

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Could it be that for these astigmatic cases, you may end up with a slightly stronger diff prescription (close-up indoor artificial night lighting) than the normalized (outdoor sunny lighting)? Due to the fact that the astigmatic blur affects equally at any distance (it does not seem to be so much distance dependent as other conditions than myopia for example).

Hi there, I noticed that you quoted my post.
So @emdiv do also have such a prescription (high astigmatism, low myopia) or are you just referring my post for the other people in this thread?

In any case I would like to talk with anyone who has a similar prescription (history) as me, because I am desperate to learn more about my (complex / unconventional) prescription.

Just referencing it for the others in this thread. I have just been reading about astigmatism for interest. (I have some double vision, but not sure if it’s related to astigmatism or not.)