I've always been curious if she's blind in that eye, or if it's just miscolored, like heterochromia.

Hitosura said:

I've always been curious if she's blind in that eye, or if it's just miscolored, like heterochromia.

Before Reimu grew a body she had half her face torn off, as shown by the scar, too
Usually in comics discoloring an eye means the character is blind, and given those events she most definitely can't see from that eye

Well, her face wasn't torn off. She was beaten severely by a human who thought she stole her platinum badge from another yukkuri.

I don't actually believe she's blind in that eye, either.

You'll see in the next part of this story.

She's blind in that left eye, you can see that in the last panels of the first part, where she said she "still cannot see through that eye".