I have the MacBookPro 15'' mid 2009 (10.9.3) , and from today I have green flickering on my monitor.
I did try with Reset PRAM, Repair Disk, also TechToolPro but i have the same problem.
It seem that the problem is with "black Color"
If I change the "total Black" I can "fix" the problem...
If i connect my Macbook with second Monitor, in Second monitor I haven't the problem but in "main monitor" the problem remains
What can I try ?