One thing that immediately stuck out to me while reading Anti-Gone were Spyda and Lynxa’s eyes, or well the absence of them until the second half of the book. At first their glasses did not seem out of place while they were outside on the boat, but once they went indoors to shop or pick up their drugs they kept the glasses on. Lynxa briefly took them off in the clothing store but she put them back on until the movie. The movie theater is the only time in the story when both characters remove their glasses.
Maybe they only took the glasses off because the movie theater was dark, but I don’t think anything is just a coincidence in this book. I noticed that Lynxa did not put her glasses back on when she left the theater but Spyda did. The glasses may be a tool for the characters see an augmented reality. Or maybe the glasses help them see reality because Spyda and Lynxa take multiple drugs before they remove their sunglasses, which altered what they saw and felt. Either way I think the sunglasses are more than what they seem to be.