User blog comment:Sicarius001/Theory on Flash Step/Sonido Speed and Effects/@comment-13442349-20130807071936

For some reason, I couldn't reply to your comment on my earlier post. Anyhow, I don't believe it affects their perception. In fact, Ichigo has noted at one point that he could see where Byakuya was going during a shunpo and reacted to it via blocking the attack. (During the SS arc)

I believe users of these "Steps" already possess the perception necessary to use these techniques.