An account

After lucid dreams (and sometimes after nonlucids): What are those blobs of colour I see in my vision? They resemble crumpled wads of paper or origami. They appear just before the dream ends and persist several seconds into wakefulness, clearly visible as I lie in bed. If I close my eyes tightly they are still there. Once it was purple and white on a violet background (viewed through a rectangular window surrounded by blackness). It vaguely resembled a neuron or a cancer cell. That one was clearly dimensional and floated in 3D space. I could study its contours and still remember its general shape. This morning it looked like an orange-and-black walnut. I fancied I was seeing my optic nerve. That is my best guess. Does anyone else see these things? What is it about the dream state (or hypnagogic state) that makes them appear? Is this related to the "sparkling void" I hear lucid dreamers talking about or is that something different?