Nebula's eyes are black because she is a cyborg. She has had her body augmented with cybernetic implants, including her eyes. The black sclera is a result of this augmentation. It gives her a menacing and intimidating appearance, which is fitting for her character as a villain. The Princess Pinky Black Sclera contacts are a good choice for cosplaying as Nebula because they accurately replicate her eye color. We've covered with different black colored contacts with smaller lens diameter that easy to wear.