I wouldn't think the supplements are responsible for the eye problems. In fact, zinc and NAC are supposedly good for the eyes. (I'm not including prednisone in this equation as it's a medication, not a supplement.)
I see that you are taking C and B but what about vitamin D (and to a lesser extent vitamin A)? A quality cod liver oil supplement contains both and might be helpful. I have found Carlson brand, in liquid or softgels, to be quite good.
As for noticing the floaters, you might just be in that phase of tinnitus where everything is noticeable and scary and annoying. I went through a horrible period like that but, thankfully, I came out of it. I guess it's a type of habituation, which seems to have more to do with how I mentally handle the tinnitus and floaters as opposed to actually eliminating them. I still have both problems but they bother me far less these days than they did just a year ago. I got to this point by learning relaxation techniques (breathing exercises, etc.) and getting cognitive behavioral therapy.
Hope this helps.
