Viewfinder eyepiece protection for glasses Canon 7

[pixelman]

Has anyone found a solution for protecting eyeglasses from the metal viewfinder window of a Canon 7s? I would love to find a solution like the "right o-ring" that can be attached to prevent eye glasses from being scratched.

 

[charjohncarter]

Masking tape works for me. Put it on the metal part that is touching your glasses and no more scratches.