Follow some basic tips to work in a better way on your computer. Do not work in total darkness where the computer screen is the only source of light, especially if you have to type or copy from a printed document.
Ensure that the keyboard and the document you are typing from are adequately lit up. The keys and letters should be visible and they should appear in focus when you look at them. If you are looking at a sheet of paper while typing, keep a paper holder adjacent to the monitor and ensure the letters are visible. Contrast also affects visibility. Black letters on a white background are the easiest to read as opposed to light lettering on a dark background.
Set the contrast correctly for your monitor, too. Outrageous colours such as red letters on a gray background are painful to even stare at. Set your desktop screen to a subtle colour and avoid pictures and graphics with fluorescent colours.