Okayokay! Clear Epoxy! E.g.
http://www.crscientific.com/epoxy-green.html
Or any other clear epoxy!
I'd disassemble the light (PITA), clean with alcohol, tape a small piece of clear plastic foil (e.g. a piece of clear polymid foil) over the front of the hole for a "mold" and then fill in the back crater that's now missing with the epoxy. I'd take it in two or three steps since the stuff shrinks quite a bit when drying. Do it face down, so the bubbles can rise. You won't have to refill to the whole glass thickness. After you are done, pull off the front clear plastic foil carefully. If it doesn't come off, cut with a razor blade flush with the lens.
When you are done, open the garage, turn the light on and have Rick over to tell you which light is distorted!
Cheers, George