I can do that too. You're misunderstanding the concept. I'm perfectly capable of drawing, eyes closed or not (though it's much harder eyes closed, obviously). I do digital art. I just conceptualize things differently. I don't have a mental image, it's more like a knowledge of what shapes go together to make certain forms. I build things piece by piece from fundamental shapes that I analytically know make certain objects or creatures, but I don't have an image of what it is until I have actually put it down in paper.

I don't know if I worded that in a way that makes sense, as I've always struggled with explaining how I conceptualize to people that have an ability I don't. I know what shapes make up a dog, but I can't see the dog, if that makes any sense.