All of a sudden my work in visio is very hard to see. All lines, saved shapes from stencils, current projects or ones from months ago look really light and thin and gray. If I zoom in very close things look normal but when I zoom out I can barely tell what is there. I haven't changed the line weight or transparency (not that that should affect older projects), in fact I have had to change the line weight just to work on things since this and it still is almost not visible when zoomed out. Its very odd. Any help is greatly appreciated.
Don't change anything in any of your drawings.
2 things I would do:
1. Change your screen resolution in whatever way you can to see if that makes a difference.
2. What I would do is check that your video drivers are up to date.