I don't like the design of Elio's eyepatch, and for some reason that's my main sticking point.
The color is too saturated, it fits too closely around his eye, and it doesn't have any external support besides a very thin band of adhesive on the edge.
I get why they designed it this way: it's colorful so it's not too medical or pirate-like, and it's just around the eye to let show expression, but it reads like an adhesive pad stuck directly to his eyelid, rather than the skin around it, which would be very uncomfortable.
It's also just about the most saturated thing in the frame, more prominent than his actual eye.
