Dark vignette appears around perimeter of screen.

There is a very dark vignette that has appeared around the perimeter of the screen, limiting my field of view and making gameplay quite irritating. I get really bad migraine headaches and this new weird dark area reminds me of when a migraine begins and I start to loose my peripheral vision and get tunnel vision. It is absolutely dreadful ...both the migraine and this newly developed dark perimeter. 

 

I did notice some graphics improvements. That water looks nice! ...however, these issues have killed the playability of the game for me. Please help. Thank you in advance!