Oh another headcanon is that Seatrolls have bad eyesight because their eyes evolved to see better underwater than in the surface, which is why they need glasses. My basis for this is only that Eridan and Meenah wear glasses, and Feferi never takes her goggles off once she's in the surface, so i think those are her glasses too lol. I headcanon Cronus doesnt wear glasses cus he thinks they are lame lol