Well, now I know that I'm not crazy - and no, I am not smoking mushrooms either! The gorgeous, vibrant colours that I see when I'm going to sleep is called "scintillating scotoma". It is defined as "a transient visual sensation of bright shimmering colours, as that preceding scintillating scotoma (aura) in migraines."
But unlike an aura, it doesn't just happen in the periphery of my vision or in just one eye, and it is much more beautiful. It happens to me about five minutes after I turn out the lights at night. It is so beautiful that I actually look forward to it! I had asked several doctors what this was and they all just looked at me strangely until I asked my new ophthalmologist, Dr. Whiteman. He cleared up this mystery immediately - it is an abnormal functioning of portions of the occipital cortex at the back of the brain - not my eyes at all! My brain has to deal with scrambled signals from my optic nerve all day, so once I stop looking at things (turn off the lights for the night) my visual cortex goes nuts for a while!
I wish there was some way to portray this phenomenon in art, but the movement is such an intricate part of the experience that a static painting wouldn't do it justice. The shimmering, pulsing flow of light and colour reminds me of Northern Lights, except that the colours are so much more vibrant; deep turquoises, electric blues, the most verdant shades of green. And then there's the gold, pink, salmon, and silver bursts of colour at one side or the other. There's no way for me to convey this to you visually.
This peaceful, dreamlike state I experience every night now is almost a perk to having optic nerve damage.
