Broke my bifocal sunglasses and decided this time to replace them with riding sunglasses that are optically correct when in a riding position. Down side was the missing bifocal. So I went to one of our forums favorite sites:
http://www.safetyglassesusa.com/
I found you can convert your sunglasses into bifocals by getting Optx 20/20 Stick-on Bifocals. So hopefully by next weekend I will have some bifocal riding sunglasses.