Sit at your desk and reach your arm straight out toward the screen. If your fingertips land well short of the glass, good. If they hit it, or pass it, you're sitting closer to your monitor than your eyes were built to handle — and you've probably been doing it for years.
The comfortable range for a monitor is roughly an arm's length: somewhere around 20 to 30 inches from your eyes to the screen, depending on how big the display is. Most people sit closer than the bottom of that range, often by six or eight inches, and those inches cost more than they look like they should.
Here's why. When you focus on something close, a small muscle inside each eye contracts to bend the lens. Hold a close focus for hours and that muscle is doing isometric work the entire time, the same as holding a light dumbbell at arm's length all afternoon. It doesn't hurt sharply. It just fatigues, and the fatigue shows up as that tired, slightly aching feeling behind the eyes at the end of the day — the thing you blame on "screen time" when a fair share of it is simply distance. Move the screen back into the 20-to-30-inch range and the focusing muscle gets to relax a little. The strain eases. The same eight hours cost your eyes less.
There's a catch with laptops, which is that you can't easily move the screen back without moving the keyboard back with it — and then you're reaching to type. The fix is the same one that fixes the height problem: lift the screen, push it to a comfortable distance, and bring in an external keyboard so your hands stay home on the desk while the display sits where your eyes want it. A stand buys you the distance and the height at once. We covered the angle that makes that work in why 6° is the right laptop incline, and our Riser is built to set both at the same time.
One more thing while you're adjusting. Distance and lighting work together — a screen at the right distance in a badly lit room still strains, because your pupils are fighting the contrast between a bright screen and a dark wall. We got into that in the monitor light bar guide. Get the distance right and light the space around the screen, and most desk eye-strain quietly goes away.
Try it for one day. Push the screen back until your outstretched fingers just miss it. It'll feel slightly too far for about an hour, the way a corrected habit always does, and then it'll feel like the obvious place it should have been all along.
An arm's length. Further than instinct. Easier on the eyes.
