Transient astigmatism

The official EM article says this double vision effect occurs when you reduce too quickly and is temporary, so you should stop reducing and wait for it to disappear.

If you reduce a cylinder too quickly, you will confuse your visual cortex, which will compensate by adding a cylinder that appears only on one side of a focal plane during the double vision resolution.

Do not get cylinder correction for it, as you would just put extra load on your visual cortex for no reason, slowing down your progress.

If it's too noticeable, you can step up, but User:User believes that you must use lots of close-up near the edge of where the cylinder appears, or on both sides of the edge if tolerable, because there would otherwise be no stimulus to clear it. If you have a huge cylinder only in the distance (very low myopia with huge cylinder), it's tricky, since stepping up to hide it would not solve the problem.