The bulk update request #14915 has been rejected.
create implication heterochromatic_eyewear -> asymmetrical_eyewear
Heterochromatic implies asymmetry to be present.
However, keep in mind we can separate the two if that is the site's preference. Personally, I'd prune asymmetrical from heterochromatic eyewear that has the same shape, and clarify it in the wiki for the tags.