MBP screen has suddenly got a green tint over it

I was just using my mac as usual and then the screen just developed a green tint, It mainly affects the black colours the most, the whole thing is still functional as usual but the colours are wrong. Another wired thing is, and this isnt just my eyes getting used to the new colours, but it isn't as bad now as it was when it had just happened, I took the bottom off and pushed the rubber bits which are either side of the display hinge thinking they might be connectors that had got loose, it hasn't fixed it but it may not have even been that that made a difference but it is definitely not as bad now as it was .

Restarting hasn't made a difference either, here is an image to show you what I mean, this whole screen should be black (or near enough), however as you can see it's green, also note the black 'yes' 'no' buttons in the middle of the screen are black and appear not affected by the green issue.

It also isn't app specific, effects system too even boot screen was tinted green and as you can see it is not uniform.

It on a late 2013 MBP 15" retina display model running yosemite, had no issues so far since upgrading.

Any help on this would be much appreciated because I'm at a loss now as to what the issue could be.

Thanks.