Bogdan

Perhaps something got confused/lost in your question..
when you say--- 'go blind'-- that may not seem to be a good question by many--IF you meant 'which is most dangerous ?' its a much better question.
please finish your profile- we sometimes cannot be good help IF we do not know where you live.

And
read the stickies and a bunch of threads in the 'Welcome' section... I hope that will encourage you to make an intro