How to reduce cyl for norms and diffs?

I’m a newbie and it’s even harder for me to absorb the huge info since English is not my first language. And trust me Google translate is kinda bad. So pls i need your help.
I have only seen how to reduce sph diopter, I havent seen how to reduce cyl yet. So pls tell me how to reduce it when it comes to diffs and norms. I’m about to make my first reduction.
Thank you so much

so sorry for asking such a simple problem, i would be thankful if you guys use simple words so it’s easier to understand

The wiki article has a section on reducing astigmatism and I think it’s very well detailed:

As with myopia, astigmatism should be tackled in small steps when selecting lenses for differential or normalized glasses. If only a small amount of cylinder correction is present, say 0.25 diopters, the cylinder correction can be dropped, with no other changes. Otherwise, cylinder should be reduced in small increments. If sphere is being reduced, cylinder should not be changed at the same time, and conversely, if cylinder is being reduced then sphere should not be changed. The only time that both sphere and cylinder should be changed, is when converting to the spherical equivalent.


When reducing cylinder value, you should never change the axis value if it has been consistent for some time. The axis only refers to the orientation in which the cylinder is affecting your eyes, and any reduction of cylinder will happen on this orientation.

Astigmatism - Reduced Lens Wiki