Prolonged bouts of video gaming can also cause symptoms very similar to Computer Vision Syndrome, Or CVS. Computer Vision Syndrome, As the name suggests, Is caused by staring at a computer screen for an extended period of time without any significant breaks. CVS, And the similar symptoms related to video games, Can include blurry vision, Eye irritation and light sensitivity, Not to mention neck and shoulder pain.
Playing games for an extended period of time can and will cause damage that builds up over time. However, There are ways to prevent and/or minimise the damage done through techniques such as backlighting. Also, Taking a 5 minute break after each half hour.
Regarding the statement that says “cause you to be bad”. It is possible for video games to effect a person. However, It does not effect the person long term. If you play a relaxing game, You will feel relaxed. If you play a horror game, You will feel anxious. After playing, These effects will quickly die off and will not change their overall personality. So the answer is no, It will not cause someone to be bad.
If you play for a long time your eyes feel increasing strain. But the second part of your question is false. Video games, Even violent ones, Shouldn’t make a person bad. People who aren’t violent by nature won’t, For example, Shoot up a school just because they played Call of Duty or a similar game.
It has been proven that games do not cause you to lose eyesight and instead, They actually IMPROVE your vision. Video Games (especially shooter games) actually help out with focusing more and gamers can do attention tasks easier. Video Games also decreased violence overall.
My sources for this is the TED talk "Your brain on video games".