personally i swear by oakley minutes. i know not very scientific, but just shedding my two pence worth. Reduces the glare to an absolute minimum, yet still let more than enough light through. I find they are especially good when the sun is very low on the horizon. Use them for flying all the time even when there is minimal sunlight they help me see better and spot many features (when flying vfr) that i couldn't possibly see when i lift them up. (except when there is no sun). I even use them when driving. Oh and they look good too
