Many modern phones use PWM (pulse-width modulation) technology to control screen brightness.
According to Eitna quoting Techadvisor, in this method, instead of directly reducing light intensity, the display is turned off and on hundreds or thousands of times per second to create lower brightness. These changes are usually not visible to the human eye, but some people are more sensitive to this flicker and may experience eye strain, headaches, or nausea.
This issue is especially important on OLED displays. Almost all new mid-range and flagship phones use PWM, and this includes many models of Samsung Galaxy, iPhone, and Google Pixel. Some studies indicate that sensitivity to this type of flicker has been reported in more than 10 percent of people.
How important is PWM frequency?
The important point about PWM is not just its presence or absence, but also the PWM frequency. Frequencies below 1250 Hz are in the “high risk” range. The 1250 to 3000 Hz range has a lower risk, and frequencies around 3000 Hz or higher are less detectable to most people.
Phones such as the Xiaomi 17, Xiaomi 17 Ultra, OnePlus 15, and Sony Xperia 1 VIII have been introduced in the lower-risk range. In contrast, the Honor Magic 8 Pro and Poco X8 Pro are examples that use PWM frequencies around 3000 Hz.
Do you need to replace your phone to reduce PWM?
No. Some phones have special settings to reduce the effect of PWM. In the iPhone 17 series you can disable the Display Pulse Smoothing option in the Accessibility section. New Motorola phones also have a Flicker Prevention or Flicker Protection option that allows switching to DC Dimming.
On Samsung phones you can also reduce the effects of PWM by increasing brightness manually and using the Extra Dim feature. On Pixel phones the Adjust brightness of sensitive eyes option can increase PWM frequency from 240 to 480 Hz and enabling Comfort View has also been suggested as another solution.
These settings do not eliminate the root cause of PWM, but they can be useful for users who are sensitive to screen flicker.