Here's my 2 cents.
I wear glasses with bifocals, but I am still more comfy piecing without my glasses on and my forehead smack up against the machine.
I try to pin, but to keep the point on the outer edge of the 1/4" line so it's easier to pull. While I am right-handed, I pin lefty and just stop, wind my arm around and pull the pin when the needle is even with it. My late MIL said you can't hurt anything sewing over a pin on an older machine as it is built tougher than these new ones.
So...I decided to give this bifocal thing a try since it had helped for the rest of my vision. There I was sewing along and decided to leave the pin in. I didn't slow down or anything. There was this horrendous noise. The machine needle broke, came flying at me and hit me right in the glasses....which I only happened to be wearing. The pin was bent in this strange S shape and I had to dig it out from behind my bobbin case. I was so scared I hurt my machine. Luckily, it was alright.
I have never sewn over another pin....but I still don't piece with my glasses on. I guess I'm just weird. :roll: