Quote Originally Posted by animus
Maybe you should rewatch the episode before you make that statement. This is Kisame's exact quote from DB's translation, "Itachi-san, it's dangerous for you to use your eyes too much." Kakashi himself then said, "Besides using a large amount of Chakra, using that technique poses a huge risk to your eyes. Right, Itachi?" And Itachi's answer to that was "An impressive analysis for only having it seen once." Meaning he is not only praising Kakashi, but affirming to the fact that it does in fact damage the eyes. Why do you think that flashback was even included? Because it led up to Kakashi's explanation of the dangers of the Mang Sharingan. Or do you think the huge risk to his eyes is getting teary eyed whenever you look at the sun? Sure, Kisame's words were not something as clearcut as "They damage your eyes." but when you take it in context with Kakashi's statements they compliment eachother.

Ok but you are still combining Kakashi and Kisame's statement into one. The point I was making is there is no way that Kakashi is going to infer permanent eye damage from "It's dangerous to use your eyes too much." That same warning has been given many times to many different characters and it was always in regards to chakra usage. There is no precedent set for Kakashi hearing that and thinking eye damage. In general, we interpret what we hear based on past experiences and thus Kakashi would just interpret that as a warning about the chakra strain of the technique.

That fact that Kakashi uses the word "besides" is implying that on top of the chakra requirements Kakashi had made an extra insight into the dangers of the technique. I still think finding the scroll is the most plausible solution.