I've used a twist tie to repair before. Wish I had some pictures to show you.
Remove the entire white plastic part. Strip the outer casing off of a twist tie. Run it through one of the screw holes on the lens and over the top of the rail then through the 2nd hole next to it. Twist the ends of the tie together under the lens and bend them flat so they won't touch anything inside the CD drive. Then put some glue on the twisted ends to help reinforce so they don't come apart over time.