I'm not sure.

Thankfully the effect is fairly unnoticable during daylight hours, although if I close my eyes I can see that the colours are still there, but more faintly. It's at its most annoying in the dark, when I open my eyes and they're still there, blocking my vision. Luckily they go away after a few moments when my eyes readjust.

Last time I had a routine check by an optician, they didn't find anything wrong. But I didn't mention this effect and I suppose they wouldn't be looking for it.