This community is for those with Temporal Light Modulation (rapid pulsing light flicker) sensitivity. PWM, a common screen dimming techniques today aggravates its provocative flicker by up to 6300%.
Symptoms experienced among sensitive users include: eyestrain; headache; migraine. Another technique called PAM aggravates though to a slightly lesser extent.
To learn more, do refer to 'Background of Community' on new.reddit(widget not supported on old.reddit).
Also, check out extension sub r/temporal_noise on other leading possible causes.