2015 Macbook Pro Retina 15in display with strip of brightness around boarder

Hi,

I have an issue with my current mid 2015 Macbook Pro Retina 15-inch screen. There is a strip on the right and top of the screen which is of a different brightness ( a lot brighter than the rest of the screen). The screen is significantly dimmer than my partner's 2017 13 in macbook pro with the touch bar, as well as my older 2014 11-inch Macbook Air.

Any help would be greatly appreciated.