Ensure that every time you use your computer that you are sitting comfortably. You will be amazed at how much time can pass when you just log on to check your email. You might end up spending an hour when you only intended to spend 5 mins.
Staring at a computer screen for any extended time can put a strain on your eyes. Make sure the screen brightness is suitable for the amount of light in the room. If you have percripstion glass’s for reading ensure you wear them when using your computer.