In a word, Perfect.  The Cocoons over-the-prescription-glasses perform exactly as advertised, & I'm more than happy to give them infinite numbers of thumbs up.  I prefer the extra coverage that the side pieces afford, & for me, the gray lenses block glare without distorting the world's colors beyond recognition.  The Cocoons have flexible bows, so you can squeeze your head to your heart's content, but mine fit snugly without further manipulation.  They slide on & off easily ~ no fumbling required.  Will probably buy another pair, perhaps with amber lenses this time.