Screen developed flickering problem

Hi, i have had my

iMac Intel 27" EMC 2429

Model A1312 / Mid 2011 / 2.7 & 3.1 GHz Core i5 or 3.4 GHz Core i7 Processor since 2011 with no issues until last week when the screen started flickering. Only thing that 'fixes' it is to uncheck the auto brightness and reduce the screen brightness just enough to make the flickering go away. I am worried the whatever the issue is will continue to get worse. Any inputs on what is starting to fail ?

Thanks