I believe 6/6 is the metric equivalent of 20/20 so that's pretty good. However, if you're going to get correction for 6/15 you might as well go for an improvement in the other eye as well. This could possibly bring both eyes up to 6/5 or even 6/4. Think how much safer you will feel if you do this. You could have the lenses put into some cool looking shades of your choice.