Yeah, you're right. Sometimes the color isn't consistent.
Cuz Vincent (ML) original eye colors is Blue. While Lucas eyes is Green. In real life when we actually do an eye transplant, our original eye color will retain and the donor eye color should not be visible.
But I think the artist purposely let Lucas eye color remain to highlight his sacrifice that returned back Vincent's eyesight.
no that's not true if you look back to the first couple chapters Vincent has green eyes, and Lucas is the one with brown eyes, so it's just inconsistent art
why were his eyes blue for a couple of panels? I would understand if they were brown or green but blue is pretty random