Working late at night in front of your bright screen might be quite troublesome to your eyes. For this reason, programs like EasyOnTheEyes were developed: to help you reduce the luminosity level of your display and avoid dealing with sight discomfort.
macOS already provides you with features to help you adjust the color temperature of your screen. However, getting to those options might take a while as you would need to launch System Preferences and look for the aforementioned features. This is why EasyOnTheEyes might be a better solution. It lives on your Menu Bar and you can immediately adjust the luminosity level of your monitor.
You can choose between 6 profiles: Off, 1,2,3,4, and 5. Choose the one that fits your needs and the program will immediately apply the necessary changes.
Personally, I'd like the utility more if it would feature options for launching at system login and for defining global hotkeys to immediately change the luminosity profiles.
Still, the program works perfectly and comes without a price tag. So, it's up to you to decide, based on your requirements, if it's worth installing this utility on your computer or not.