Screen Light, off on the top?

[gbentenza]

Since few weeks ago the light of the screen (on the top) was kind of blinking at the startup in the morning, but after some minutes it came back to normal. And now, after beeing on sleeping mode for few hours, the top of the screen is quite dark as if the light on the top just give up. So now I have a light degradé from light-bottom to dark-top. Is there anything I can do?
I work all day in it with photography...

(iMac OS X, with a 2.66GHz Intel Core 2Duo processor, from 2008)
Thank you! G.

 

[Kaveman]

This is a hardware problem, you will need to take it to an AppleCare Service Centre near you.

 

[gbentenza]

thank you Kaveman.