Quote Originally Posted by maodiver View Post
no, because it is ridiculous to believe that a trout can't see it...I mean, you can see it, right? and a trout has much better eyesight underwater than you do...
Not that I'm advocating 7x, but to be fair to those who do, their argument isn't that the fish can't see it, it's that it allows a more drag-free presentation, and that for nymphs, that it sinks better.

The former can just as easily be accomplished by a longer leader and/or a slack-line cast. A heavier fly and/or a tuck cast takes care of latter. Or you can use a finer leader and lose more flies and fish.