Since this model has a LED-backlit TFT active-matrix display the problem could be the controller or the display.'' Is there any history you've neglected to share (liquid spill or dropped).''
Neither repair is easy, no would I start either one unless I knew it was the correct one.
I'd say take this to Apple, or an Apple Certified Repair shop to find out what is the true problem.
''If this answer is acceptable '''please remember to return and mark it'''.''