On rare occasions i get this sensation when lying down. This sensation is hard to describe but i'll try..

It's like the blackness behind my eyelids becomes darker in a sense. And i am zooming in, untill the point of black becomes larger and larger and eventually it becomes like a small dot. And then it stays stable like this.

There's more to it but that's as far as i can describe at this point. I have a feeling i should do something but any attempt of stimulating does not change the blackness. Does anyone know what i'm talking about here? What can i do to get something useful out of this?