What does the "with eyes so dark" line of Halsey's "Graveyard" mean?

Question

In the song "Graveyard" by Halsey, there's one line that goes like this:

You look at me
With eyes so dark, don't know how you even see
You push right through me

The song overall is about someone in a relationship with a person who's heading into a bad place (mentally) and their partner following them there.

But what does this line about "dark eyes" mean? Is it referring to physically dark eyes, like from lack of sleep? Or what?

Answer 1

The singer describes being in a relationship with someone who is unhappy and self-destructive (“drunk at the steering wheel”) but loves them so much that she would follow them to destruction, as she declares repeatedly:

I woulda followed all the way to the graveyard

In this context, “dark” has a couple of meanings. First,

dark, adj. 9. Not able to see; partially or totally blind; sightless.

_{Oxford English Dictionary}

That is, the subject of the song is unable to notice the singer (“don't know how you even see”), and “pushes right through” her (treats her as if she doesn’t exist). Second,

dark, adj. 5. a. Devoid of that which brightens or cheers; gloomy, cheerless, dismal, sad.

_{Oxford English Dictionary}

This is metonymy, the eyes standing for the person.