I was hoping to use these flip up sunglasses while out cutting grass so that I can just flip them up when it gets dark or if I need to go into the shed and get gas. Unfortunately the lenses seems hazy and annoying. It might be the light reflecting between the lenses of my prescription glasses and these flip up lenses.  Or I might be too spoiled by my crystal clear prescription sunglasses. Either way I don't like them and wouldn't recommend them.