Drawing glasses is quite easy. You just need to draw half of glasses. I draw the left side only. And make a mirror to the right side. So, we have left side and right side in the same shape.
This is the preview of glasses that I've mentioned above.
For the shadow at top side, I make it not mirror technique, but I do it manually. Just a simple line to make it shiny.
Here you can download for free the vector above. You can open it bu using corel draw 11 and above.