Tools
Backlight bleed test
Dim the room, go full screen on black, and look at the edges.
How the test works
Black screen
Reveals light leaking around the edges of LCD panels. Set brightness to your usual level; maximum exaggerates it.
Grey levels
Dark and mid greys show clouding and uneven brightness across the panel.
What your results mean
Glow that changes with viewing angle
That's IPS glow, a property of the panel type. Move your head: if it shifts, it's glow, not bleed.
Bright patches fixed at the edges
That's backlight bleed. Mild bleed is common; severe bleed visible in normal use may be covered by warranty.
Questions
Is backlight bleed normal?
Some bleed is normal on LCD panels, especially in a dark room. It's a problem when it's visible in normal content and lighting.
Do OLED screens have backlight bleed?
No. OLED pixels make their own light, so there's no backlight to leak. Look for uniformity issues on dark grey instead.