Tesla experienced flashes in his peripheral vision.

He also suffered with intense anxiety.

From what i've found out so far the combination of anxiety and sympathetic nervous system responses - due to the body being over-ramped can cause visual disturbances.

When in fight-flight mode the body sends blood to where it's needed most for survival - ie muscles to be able to run to safety...and our senses become pin-sharp - smell and sight especially.

So in constant anxious/sympathetic nervous response mode during everyday life visual anomolies can result.

I've seen flashes for 2 years.

Just one rational reason for such an experience.

Of course, it could be this ascension thingy occurring too - i don't dispute that.