When the iPad Pro was first introduced, it comes with a display adjustment feature known as TrueTone. The TrueTone is intended for colour adjustment based on different environment where the sensor detects the light changes and adjust colour warmth accordingly. In the new iOS 11 Beta 6 update, it can be seen that the TrueTone technology previously available on iPad Pro gets featured on the upcoming iPhone 8.
With this feature enabled, you will get less eye strain when you stare at the display for a long period of time. However, we recommend you to always rest your eyes periodically for the best care of your eyes.