Dave, I find that it helps me a great deal to take a brown cardboard box and use a 2 or 3" dot @ 100 yards. A tan box or piece of paper with a 3" black dot is also a lot easier for me to see. I prefer the orange dot in dim light and the black in bright sun.

You just have to get back in touch with your sights and have your eye adjust. I couldnt shoot for chit with open sights @ 100 yards due to me doing to much shooting at 50 and 70 yards.

I am finally back to shooting my 100 yard mark and its getting easier for my eye to focus on the dot and the sights.

Gotta practice for a while until you get used to them again.