Faint lines in top left of the screen? Random?

[chriswright101]

I'm just noticing some very VERY faint lines, 3 in total, in the top left of my screen.

I'm in the middle of doing a dissertation so I haven't got time to really power everything down and restart it. I'm hoping the problem just lies in over-using it today, because it's definitely a new glitch as of today.

Anybody else experienced this problem?

 

[chriswright101]

Ok, after a restart and shutting down, then coming back to the iMac 10/11 hours later, I am now noticing that the lines are still there. They get more noticeable as the computer progressively gets used more over the course of the day.

Can anybody enlighten me with advice? Doesn't sound like a big deal, but it's an expensive machine that I would rather have in pristine condition for as long as possible.