Digital eye strain: what actually causes it

What is digital eye strain?

Digital eye strain covers the eye and vision symptoms that come with long screen use: tired, sore or dry eyes, blurred vision, headaches, and aching in the neck and shoulders. It affects an estimated half or more of computer users. The symptoms are usually temporary, but for many people they come back every working day.¹

What causes it?

• Focusing up close for hours. Your eyes work to hold focus and point together at a near screen.
• Blinking less. Concentrating on a screen reduces blinking, which dries the eyes. See dry eyes and screens.
• Uncorrected vision. Small prescriptions, astigmatism or eye teaming problems add effort.
• Glare. Bright, harsh light makes you squint.
• Flicker. Many screens pulse their backlight or flicker their pixels.

Can screen flicker cause eye strain?

Your retina responds to flicker far faster than you can see: researchers recorded it keeping time with a fluorescent light pulsing 145 times a second.² In a double-blind office trial, replacing flickering fluorescent lights with nearly steady ones cut eye strain and headaches by more than half.³

Many monitors dim with PWM, flashing the backlight on and off, and many 6-bit panels flicker pixels between shades (FRC dithering). Read about PWM sensitivity and dithering sensitivity.

Is blue light the cause?

Probably not. A 2023 Cochrane review of 17 trials found that blue-light filtering glasses may not reduce eye strain from computer work in the short term.⁴ Blue light’s best-documented effect is on your body clock and sleep, so it matters most in the evening. See screens, blue light and sleep.

The Firelight is low in blue light because filament light naturally is. For eye strain, the bigger screen factors are flicker and glare.

Glare, posture and a sore neck

In a lab study of computer work, direct glare increased blink rate, made people bend their heads forward and raised blood flow in the trapezius, the big muscle across the top of the shoulders.⁵ Eye strain and neck strain often travel together; see neck, jaw and shoulder tension.

How to reduce digital eye strain

• Follow the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds.
• Blink fully and often, and ask about lubricating drops if your eyes feel dry.
• Get an eye exam and mention how much time you spend on screens.
• Keep the screen about an arm’s length away and slightly below eye level.
• Match screen brightness to the room and cut glare from windows and lamps.
• Choose a screen that doesn’t flicker: DC dimming, no PWM and no FRC dithering.