Just wanted to ask....have you checked all the inserts in your eyes? If you have one that is missing, broken, has sharp edge, that could be the cause of the fragile line. The friction of it rubbing a bad spot on the insert or lack of insert could weaken the line causing your problems. Just a thought is all and something to check. sometimes, those inserts are never noticed to be damaged, but upon closer inspection, you may find something out of place.