I think this all boils down to sensitivity. I drive a car in the United States, but would not do so when visiting friends in Charedi neighborhoods in Eretz Yisroel, where women don’t drive. It is conspicuous to drive there, similar to a woman driving a large truck here in the United States.
Many sunglasses that are worn make a fashion statement and call attention to the wearer as do too fancy clothes or too much makeup. One can’t put a guideline on what is too much makeup, it’s really a sensitivity.
A person who needs sunglasses to protect his eyes and yet wants to be modest and refined looking can certainly look for some that are quieter and more conservative than many of those being sold today. For an important interview or business meeting no one would try to achieve the “cool” look. The same should be true for the frum Jew always.