Doubt about astigmatism

hello, I feel that you have a lot to understand about astigmatism. can you help me, i have some doubts about astigmatism

  1. whether the active focus for astigmatism (not sph) is done at the edge of double vision or outside the edge of double vision. I see other people say that active focus on astigmatism can be done far outside the edge of double vision because it is only directional blur

  2. how to calculate edge of directional blur? is it the same as sph for example if I reduce my cyl by 0.25 then I will get edge of double vision as far as 400 cm (100: 0.25)

  1. You need blur to stimulate refocusing. If you’re working on astigmatism, you need to be on the edge of directional blur.

  2. Stenopaeic Slit

I did not find a way to find the edge of double vision using stenopic slit. if I just want to reduce my astigmatism in normalized, does it mean I have to work on the edge of double vision in my normalized?

It should find the ends of astigmatism blur, not double vision. Your distance to blur should be closer at one angle than the opposite angle.

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