Why did Anakin keep his eye scar when Luke got completely healed of much deeper scars from the Wampa?

Now, I know that the Wampa scene was apparently introduced to account for Hamill’s changed nose from his recent car accident but it does seem possible that after the Bacta tank treatment and some other Medical Droid attention, he was completely healed of them, then why isn’t this the case with Anakin? Did he just think that the scar looked cool and leave it there?

Edit: Apparently the wampa scene was written even before the accident, so it really is possible to heal very deep scars in the galaxy far, far away, which makes me wonder why Anakin (and then Vader) still had theirs.