Eye color assignment to certain skins?

[neonal18]

Hi all. I was wondering how I could assign a certain eye color to a certain skin tone. I saw that this is done with vampires in Nightlife. Is it done with the eye that appears on skin tone textures? If not, how?

[HystericalParoxysm]

Nightlife vampires are done via a skin overlay that covers the face and body skin as well as the eye textures. It's not an actual skintone so much as a semi-transparent layer on top, which is fully opaque over the eyes, giving the appearance of a changed eye colour. Mods are available which make the entire overlay invisible, allowing sims to retain their original skin and eye colour.