The screenshots will explain better than I can. As I go further away from blocks, they loose pixels and get smudged into a blur. This is the way that the game stops itself from loading every pixel when you are far away right? Well it's happening right next to me now. I was playing Minecraft earlier today then I started it up again now, get on my world and everything is like this!

I haven't tried restarting my game yet because I needed to get the screenshots. I'll edit once I have. EDIT Okay. I've restarted and it's still weird. I've also found out that it doesn't happen to transparrent blocks or entities.