That is an interesting article on why Computer Screens are not green-on-black anymore. Although, many developers like to have their terminal/IDE screen look like that, myself included, there are other people who finds it uncomfortable, and the reason for that is astigmatism!
Apparently, people with astigmatism have a hard time reading white text on a black background, or green text in this case because of the light levels that goes into the iris.
To read more about this check the following article from @Gizmodo
One Surprising Reason Computer Screens Aren’t Green-On-Black Anymore.