# Having trouble figuring out my astigmatism

Yes I have! I’m have officially -0,75 and -1,25 cylinder (officially because I think it’s lower now but can’t really tell), and I can distinguish between the astigmatism blur and the “total” blur in the wheel…

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What are your cm measurements to each bluer for each eye?

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Sam, you’ve been busy. While you’re at it I hope you will one day get to my misspelled user name.
Wanted to show @JuliaBcn using her cm measurements but let’s just use my own LE:

1st point of blur = 24cm
2nd point of blur = 29cm

SPH = 100/29 = 3.45
CYL = 100/24 - 3.45 = 0.72

In opto terms: -3.50 SPH -0.75 CYL

Are you astigmatic?

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Only checking public misspelling.

Was hoping not, but apparently so. Does it matter if the measurement are taken direct from the screen or is printing out the astigmatism wheel a necessity.

Shouldn’t matter. I just found it much easier to use the wheel on a setup similar to/inspired by this: https://endmyopia.org/brilliant-diy-centimeter-measuring-tool/

Yes, I made a wheel based on this but couldn’t get anything meaningful from it.

Oh I see. I found this ‘wheel’ to be more useful:

Copy/paste that image into a Word doc and print. Use the image on the right. Hold it close enough to your eye so that all of the lines are dark. Gradually move it away from your eye. If you do not have astigmatism, all of the lines will blur equally and at the same time. If you do have astigmatism only some of the lines will blur at first (1st point of blur) like in the image on the left.

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It gets scaled, based on image size, margins and paper size. What is the diameter of the wheel after printing?

Shouldn’t think that matters terribly though I haven’t experimented with different sizes. The diameter of the image I use is 7cm (one set of lines end-to-end, not including numbers).

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I am -1.25 with -1 cyl ×10° in left eye and -1.75 in right…i cannot see near text clearly with left eye…is it due to cyl?

What is meant by divide into 100?

The measurements in cm of your distance to blur.

Can I use that image ( the spoke wheel ) on my computer monitor?

Don’t see why not, whatever seems to work best for you.

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Here is the right one on it’s own.

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I like simple things so I have to say I like this pic best for astigmatism measurement.
With the instructions from @Astigmatism_Assasin. Thank you!

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Why is the second measurement SPH? I’ve been using this method to calculate CYL only and calculating SPH by measuring distance to blur with text. What I noticed is that the first measurement from this spiral is always closer to my SPH measurement from text (and SPH value in my subscription). The same is true for my brother–I convinced him to start EM at the same time I started.

Both the first and the second measurements in cm are sphere calculations. The first measurement is on the axis where your eyes are strongest (least sphere correction is needed). The second is on the axis where your eye is the weakest (the most sphere correction would be needed to achieve 20/20). Both are calculated as 100/distance in cm. The difference between the two sph values obtained above will give you the cylinder value.

Example:

if on strongest axis (let’s say 0-180 one) you measure 15 cm, the sph value is 100/15= -6.66 D
if on weakest axis (let’s say 90 one) you measure 14 cm, the sph value is 100/14= -7.142 D

Cyl value in this case would be the difference between the two spheres values like this: 6.66-7.142 = -0.476D Cyl . rounded to -0.5D cylinder on the 90 axis.

Hope this helps a bit more

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@chives, as you calculate the sph or the cyl, make sure you account for the vertex distance, if you are wearing glasses and not contacts. It does make quite a difference in the higher strength lenses.

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