What Is The 20-20-20 Rule For Screen Time?

With smartphones, computers, and TVs being ubiquitous in modern life, digital eye strain (DES) has become a real concern. Symptoms of DES include irritated eyes, blurry vision, and light sensitivity, and they are likely to show up after staring at screens continuously for two or more hours. Activities that can lead to excessive screen time include doom scrolling, high-intensity gaming sessions, remote work, and reading books using e-readers. Ophthalmologists and other eye experts have long recommended a simple eye care technique called the 20-20-20 rule as an effective way to prevent or ease eye strain.

The rule is simple: For every 20 minutes of screen time, look at an object 20 feet away for 20 seconds. Since screens are usually placed at a close viewing distance, this causes the eye muscles to contract to keep things in focus (they relax when looking at distant objects). If they remain in this state for an extended period of time, they get fatigued; hence, the DES symptoms. The 20-20-20 rule gives them a little break because 20 feet is a more optimal viewing distance for allowing the eye muscles to relax, 20 seconds is roughly the time it takes them to relax, and 20 minutes is the preferred length between breaks.

But does the 20-20-20 rule work? Surprisingly, studies have yielded somewhat conflicting results when trying to pin down its impact on digital eye strain, especially in the long term. While your eyes do benefit from taking regular breaks during screen time, among other things, you may not need to strictly adhere to this rule.

A study was published on PubMed where 30 young adults were given a demanding reading task to do for 40 minutes on a tablet. The researchers measured their DES symptoms before and after the task. The study was conducted in four phases, and participants took 20-second breaks every five, 10, or 20 minutes, or no break at all (worked the entire 40 minutes) during each phase. The participants were told to look out the window during the 20-second break. The results showed that while DES symptoms increased after each task, the breaks did little to prevent or alleviate them.

Another study published on PubMed found that the 20-20-20 rule did reduce DES and dry eye symptoms in 29 symptomatic patients when they used a computer program that constantly reminded them to take breaks. That study took place over a two-week period, but when the researchers followed up a week later, after the participants had stopped using the program, the benefits had disappeared. The researchers also measured improvement in binocular vision and ocular surface health, and found the 20-20-20 rule had no meaningful impact on them.

What these studies show is that if you want to see relief from DES symptoms with the 20-20-20 rule, you would need to follow a rigid schedule for an extended period of time. But once you stop, the symptoms will return. It's good for short-term relief, but maybe not so much if you're looking for meaningful and lasting relief.

Taking regular breaks during screen time will always be a beneficial part of preventing and alleviating digital eye strain symptoms. It's just that the 20-20-20 rule isn't the magic bullet that it has been made out to be. Long-term relief comes from combining several strategies, including the 20-20-20 rule. For instance, experts advise that you place the screen 20 to 28 inches from your eyes, with the top of the screen below eye level. This makes your eyes look slightly downward. They will be slightly rested at this distance and position, which helps reduce DES.

Glare is another problem that causes eye fatigue by overwhelming your eyes with brightness. You can reduce it by turning down the screen's brightness or turning on the blue light filter, especially in dark rooms or at night. You can also turn on dark mode on your computer and phone. For websites that don't have it (since web pages don't usually adopt system-level settings), you can use a browser extension that adds dark mode to their pages. With these strategies, you don't need to buy blue light glasses.

Blinks lubricate the eyes. But when you're staring at your screen, your blink rate reduces; sometimes significantly. When this happens, your eyes start feeling dry and irritated on top of being tired. So make sure to blink intentionally more often to prevent dry eyes. If your eyes start to feel dry, use artificial tears to lubricate them and rest them for a bit.