Well you must have not searched very hard if you didn't find studies, because it took me a grand total of 3 minutes: https://www.semanticscholar.org/paper/Optim

Well you must have not searched very hard if you didn't find studies, because it took me a grand total of 3 minutes: https://www.semanticscholar.org/paper/Optimal-Line-Length-in-Reading--A-Literature-Review-Nanavati-Bias/d02c332bb95138d4bab647a7ad4f6f27556c8df3 https://www.semanticscholar.org/paper/Optimal-Line-Length-in... There are many citations that lead to other studies on the same topic.