Dark spot on the display T430

[SylVestrini]

Hello fellas,

A while ago I bought a second hand T430 (1366x768 TN display) and recently noticed a dark spot on the display. It is mainly visible from the angle the picture below is taken and on black/dark screen. When I am in front of the laptop I see nothing wrong, no matter whether the display is dark or light. When a lot of side light is coming from the window that is on the left of my desk it might become slightly visible, when I move to the side and when the screen is black or very dark. Any ideas what this might be and if possible to fix?
Thanks!

https://imgur.com/jjAYxvV

[TheForgottenKing]

Probably display damage. I'd recommend doing the FHD IPS mod anyway.