Why are there white lines running across my Macbook Pro(late 2013) screen?

My problem is that there are horizontal white lines flickering on and off on my screen whenever I move my cursor, type, or watch a video. This has been a recurring problem with my Macbook Pro Retina for about a year and a half now; I could deal with it up until recently when 2x1 inch boxes of static began flickering on and off as well. The colors of these boxes have been green, pink, grey, and white and are very annoying and hard to ignore. Also, when I'm using a hardware intense video editing program like Final Cut Pro, my Macbook screen will go black and bring up the log in screen. I don't know if there is a loose ribbon cable connecting the screen or if it's a faulty screen in general but would like to know the best course of action for repair or solving this issue.

Specs:

Macbook Pro (Retina, 15-inch, Late 2013)

Processor: 2.3 GHz Intel Core i7

Memory: 16 GB 1600 MHz DDR3

Graphics: NVIDIA GeForce GT 750M 2048 MB

Please let me know if I could provide any more info about my machine that would be of assistance.