You may think that when you turn the brightness down you are helping your eyes, but most of the time this is totally wrong.
First, let’s set some basic rules about your screen brightness.
The light emitted from your screen should match your room lighting and your screen should not look like a light source in the room.
What this means is that in dark room, your brightness should be low, and in bright room, your brightness should be high.
This should be all you need to know about brightness, but there is a catch.
Most monitors are actually super unhealthy at low brightness and the reason for this is PWM flicker.
Pulse width modulation is a cheap way for manufacturers to lower the brightness and make monitors energy efficient.
It works by turning the monitor OFF for short interval of time then back ON. The lower the frequency of this process the darker the screen, but at some point, our eyes start to adapt to this.
Our brain is slow and we don’t perceive this, but our eyes start to contact like a muscle. The iris of our eye starts to open and close continually.
To try this go to your light switch and turn the light ON and OFF fast. The feeling is not really pleasant.
Flicker-free monitors basically don’t use PWM, but DC dimming and this makes them more healthy for the eyes.
What you need to know is that if you don’t have flicker-free monitor and don’t use Iris you should put your Hardware brightness to the maximum amount.
Iris controls the brightness without PWM for all monitors. It works by hooking to the graphics pipeline and changing the image to a darker one before it is sent to the monitor and this is why Iris helps with eye strain caused by bad monitor.
If you have a monitor with PWM flicker set your hardware brightness to the max and download Iris to control the brightness without PWM flicker.