Many people claim that sitting too close to a monitor or TV will permanently damage your eyes, but is there any empirical evidence to back it up? And what is the ideal sitting distance for regular computer users?

The answer is quite simple.
Monitors and TVs pose no risk of permanent eye damage. None at all. It’s a myth that started as an old wives tale and keeps being perpetuated without any solid supporting evidence. The truth is, it doesn’t matter how near or far you sit.

As a guideline, start from arm’s length and adjust accordingly. A smaller screen (e.g. under 14 inches) might be more comfortable up close while a larger screen (e.g. over 20 inches) might require that you sit further back. But anything goes as long as you’re comfortable.
The real secret to fighting computer-related eye fatigue is to take frequent breaks and give your eyes some rest. Doing so could help you sleep better and improve your health.