Elio has an eye patch because he injured his eye in a fight with another kid. In the movie "Elio," the character gets his eye injured during a confrontation, and doctors ask him to wear an eye patch to protect it so he doesn't touch that eye. This injury and the resulting eye patch are part of the film's story and character development. Before the movie's release, there were theories that Elio might have amblyopia (lazy eye), a common childhood vision condition treated by wearing an eye patch on the stronger eye to strengthen the weaker one. However, the official explanation in the film is that the eye patch is due to an injury from a fight, not a medical condition like amblyopia. The eye patch also fits into Elio's imaginative character who dreams of being a "space captain pirate," and it makes him visually distinctive. Pixar animators have noted that the patch serves both thematic and practical purposes in the animation design. In summary, Elio wears an eye patch because of an injury sustained in a fight, and the patch visually supports his unique, imaginative character in the story.