When looking into the distance, there is a great abundance of flashing particles in the background, as sen in the screen shot. They appear only present on the terrain, and not in the air blocks.
MC-74734
Excessive Flickering Particles in the Distance
Resolved
Duplicate
0
Alan Raterink
No User
(Unassigned)
Unconfirmed
Minecraft 1.8.1
Retrieved
You might play around with the Mipmapping settings in the video options to see if that changes anything.