The color changes I experience are the same as tisriley, decabea, and pwb. For me it happens most often while I'm trying to work and fall asleep (I have a low blood pressure and some meds that make me sleepy, plus sleep apnea & I can't always wear my C-Pap.) for a few minutes or just have my eyes closed for a few minutes. When I open my eyes I'm usually looking down at the keyboard and it will be a different color. Lately it's been navy blue every time but before it was a variety of colors. I've also had an entire room be a different color, with all the edges brighter than the rest. I have heart failure, for which I have an LVAD (Left Ventricular Assist Device). It's a pump inserted in my heart that pumps the blood for it. I'm also on multiple medications.
I'd love to hear any information that is discovered!