Blue light filter.
This is the one I use. Been using it for years to protect my eyes from the harsh blue light. Makes my eyes feel more comfortable because you can dim the screen to suit you.
It has different settings. Just pick one that you prefer. Has different colour filters, so you can find the one you like the most. You can also adapt the intensity.
Comes with a handy flashlight too.
A tip though… I do have to switch it off when taking photos with my phone as they come out darker with the filter on.
But there is a helpful settings bar that isn’t intrusive, so it’s easy to turn on and off. As with the flashlight.
Free from Google play.
One Vision Blog 