In short, wearing gauze, casts, eyepatches and similar items for Fetish Fuel purposes, or seeing it as such.
Particularly well-entrenched as a Moe trait in anime/manga circles, and featured in the cosplay style/fashion trend called kegadoru ("injured idol"). The basic psychology isn't difficult: the appearance of injury implies the need to be protected, which inspires a desire to approach and [...] [tvtropes.org]