Seems to symbolize duality, like above/below or black/white masonic checkerboard.
>Internal world/external world
>Multiplicity
>Programming/SRA/Trauma-Based Mind Control/MKUltra
Aside from the symbolism, it seems like many of the older generations of satanists have one eye droopier than the other. My guess has always been that the brain corresponds to sides of the body, and perhaps the programming (using alters on one side of the brain, or having one side of the brain responsible for certain functions) is what's caused differences in facial/eye symmetry either over the years or at the exact moment the photo is taken