problem with tobi's eye

[Roby]

Really Tobi has had Kamui since he fought with Minato. How come Kakashi did not have MS way back then?

Like I said in post above he did not know how to activate MS. Took him forever to activate MS when they chased Deidara and around that time he learned that he infact did have MS

ok then how about this, when kakashi was fighting against the fake itachi during the garra story,how did kakashi know itachi was going blind from using his MS unless kakashi was having vision problems himself with his MS

Kakashi happens to know a lot abaut Uchiha history and sharingan/rinnegan overall. And in chapters from part1 he discusses abaut them a lot with Jiraya or explains to Sasuke time to time