Quote Originally Posted by animus
I do believe it's easy to deduce that he might have a Mang Sharingan. The direct quote from DB's subs is "Itachi, how bad has your eyesight gotten?". I think it's one of those questions that you use in comparison to yourself. To emphasize my point the question could possibly be asked this way, Itachi how bad has YOUR eyesight gotten? You say it's a taunt, but do you really think Itachi would really have a shocked reaction like he did to a taunt? Kakashi already stated to Itachi that he knew the technique had dangers to the eyes from use, and like you said Itachi even praises him for it. So it's an extremely logical situation to assume Kakashi might have it just from the next statement and Itachi's reaction.
It can`t be a comparison, because in order to compare you need two "subjects" to compare, if he said something like... is your eyesight as bad as mine? then it will be completely plausible, kakashi deducted that itachi can`t use mangekyou a lot, because

A) Itachi was tired the first time he used it

B) They even showed a flash of Kisame saying out loud how he shouldn`t be using it or whatever (this one should be enough giveaway...)

Kakashi: After using that technique, you were very fatigued and retreated inmediately

(Flashback) Kisame: Itachi-san, it`s dangerous for you to use your eyes too much

Kakashi: Besides using a large amount of chakra, using that technique poses a huge risk to your eyes right itachi?

I`m focusing in what Kisame said and second part of Kakashi`s last sentence... they basically sayd the same, i don`t see something that needs to be overanalyzed or anything, maybe i`m missing something.