ON can cause changes in your color vision, I know that reds get dimmer for me when I have a mild bout.
I just learned recently that intermittent blurriness can be ON also, didn't know that until it happened to me.
It's not just blindness and pain, it can be milder at times.
I have no idea of other causes of your symptoms, but there may be some.
Have you seen an Opthomologist? (not optomitrist)
If not, I would.

Best of luck