Link: Harvard Health Publishing / Harvard Medical School
This fairly brief article does a good job of summarizing pros and cons of gaming, both physically and mentally.
It lists several gaming injuries, which I believe would show good objective evidence of overuse.
It provides criteria for identifying Internet Gaming Disorder (As per the American Psychological Association).
It provides tips on "Gaming in Moderation" including several tips on preventing injury (One of which I have started using this afternoon, regarding giving your eyes a break for every 20 minutes of screen time).