The Xbox Series X UI update includes an upgrade to 4K resolution, Night Mode, a Blue Light Filter, and more. To enable the Blue Light Filter, go to Settings, select Accessibility, select Night Mode, then select Display.
The Night Mode Display has options to dim the screen and apply a Blue Light Filter. The Blue Light Filter option has a bar to adjust the filter, giving users the freedom to choose its strength.
Since the Blue Light Filter is part of Night Mode, users can select when Night Mode turns on or keep it on always. Users can adjust the settings of Night Mode to only include the Blue Light Filter, but there are also options to block the HDR display and adjust the brightness of the Xbox logo lights on the console and controller.
The Night Mode Display settings can be seen below, comparing screens with no Night Mode on and one with Dim at nearly 50% and the Blue Light Filter at nearly 90%. The change is pretty drastic, but the settings can, of course, be adjusted for preference.
The Blue Light Filter will allow users to adjust the screen to put less strain on the eyes. According to a Harvard Medical School article, "Blue wavelengths—which are beneficial during daylight hours because they boost attention, reaction times, and mood—seem to be the most disruptive at night." An experiment conducted by Harvard researchers found that blue light suppressed melatonin for about twice as long as green light.
By turning down the blue light on an Xbox Series X, users can decrease the strain on their eyes and prevent sleep disruptions from continuous exposure to blue light.
For more Xbox Series X guides, check out Best Keyboard and Mouse for Xbox Series X/S on Pro Game Guides.