Quote Originally Posted by DB_Hunter
Besides, it seems to fit in also when Kakashi tried telling Naruto and Sakura near the beginning of Shippuden that he had learnt a cool new technique.
lol, the man nicknamed the "copy ninja" learned another technique in 3 years....big surprise

As for the whoel eyesight issue, at first i thought that kakashi had caught itachi in his own genjutsu (like kurnie did back when she faced itachi), and itachi hadn't realized it yet, hence the "how bad has your eyesight gotten" comment. But that doesn't seem to be teh case.

I dont think that it was in reference to the strain from using MS though. Remember, the sharingan is as feared as it is because of the power of insight it has (second only to the bayakugan)...so im thinking kakashi had made some sort of discovery about itachi, or perhaps itachi had failed to realize something...which is why kakashi commented on his eyesight getting bad.