1. There is a preset created by Jeff Kaczor called eyes to improve which can run 24/7. I have heard the flashes that seem that come when it is dark can be indication of torn retina.
2. I would also try heavy metal detox settings (don't do mercury if you still have amalgams), as heavy metals can affect your optic nerves and brain in case that's the reason you are experiencing flashes. I get flashes in both eyes simultaneously and I know for me it's a neurological issue.
For more details, please check the link: