Why Screen Glare Keeps Your Brain on Alert

The cost of screen use usually gets described in mental terms — fragmented attention, shallow processing, distraction. Those are real, but they miss a more basic mechanism: sensory cost. Screens hijack the orienting reflex, an ancient nerve circuit that evolved to detect new things in your surroundings, and they keep that circuit partly switched on even when you aren’t actively looking at them.

The orienting reflex, first described by Soviet physiologist Evgeny Sokolov, is a built-in response to anything new or changing. When something new shows up in your senses — a sound, a movement, a change in light — your brain briefly shifts resources to evaluate it ^[1]. This reflex is essential for survival: it’s why you notice a branch move in the forest. But it’s badly matched to a digital environment where things change hundreds of times an hour.

Screens trigger the orienting reflex through several channels. The visual flicker of refresh rates, motion from animations and video, and brightness changes from notifications all set it off. The problem isn’t that any single trigger is costly on its own — it’s that this reflex never fully settles down around digital stimuli, because the stimuli keep changing. In a natural setting, the orienting reflex adapts to steady input and stops firing. In a digital environment, steady input is rare.

The evidence for the most commonly recommended fix — blue-light-blocking glasses — is weak. A 2021 review found that blue-light-filtering lenses had no meaningful effect on eye strain, sleep quality, or visual performance compared to regular lenses . The blue-light explanation is popular because it comes with a product to sell, but the data doesn’t back it up. The problem isn’t the color of the light. It’s how unstable your visual field is.

The thing that actually works is sensory rest: stretches of low-change visual input that let the orienting reflex power down. The easiest version is time outdoors with your eyes on the horizon — no phone, no book, no podcast. A horizon offers almost nothing new to evaluate. The orienting reflex gradually settles, and the mental cost of constantly orienting drops. [OPINION]

The recommended dose is 20 minutes of outdoor light — ideally in the morning, though any time of day helps — spent specifically looking at the horizon or distant objects. A horizon is the clearest signal of “nothing to evaluate” your visual system can get. It triggers the opposite of the orienting reflex: relaxed, low-effort visual processing that lets your nervous system step back from constantly scanning for threats.

This idea is backed by Attention Restoration Theory, which proposes that focused attention (the kind screen work demands) is a limited resource that needs to be replenished by a different kind of attention — the effortless kind natural environments trigger . Natural environments are “softly interesting” — they hold your attention without demanding it — which lets your focused-attention system recover. Screens are the opposite: constantly demanding, requiring focused attention nonstop.

Two sensory-rest sessions a day — 20 minutes each — are enough to meaningfully lighten the load on your orienting reflex. The first should happen within an hour of waking, to set your circadian rhythm and clear out the sensory buildup from the night. The second can happen any time in the afternoon when screen fatigue peaks. It costs nothing. The only barrier is the urge to fill every gap with more input.

The pushback is almost always the same: “I don’t have time for two twenty-minute breaks.” That objection is itself a symptom of the problem. Your orienting reflex has been running all day. The twenty minutes isn’t lost time — it’s recovery time that makes the rest of your day more productive, because your sensory system is no longer partly switched on. Thinking of it as a break misses the point. It’s maintenance. The same way you wouldn’t run a car engine at full throttle all day without letting it cool, you shouldn’t run your orienting reflex nonstop without giving it a chance to settle.

Disclaimer: This post is for inspiration and education, not medical advice. Everyone’s body is different, so please check with your doctor before changing your diet, exercise, or lifestyle routine. By using these tips, you agree to do so at your own risk.

References

^[1] Sokolov EN. Higher nervous functions: the orienting reflex. *Annual Review of Physiology*, 1963. DOI: https://doi.org/10.1146/annurev.ph.25.030163.002553

^[2] Kaplan S. The restorative benefits of nature: toward an integrative framework. *Journal of Environmental Psychology*, 1995. DOI: https://doi.org/10.1016/0272-4944(95)90001-2

Kurt Greiner

Kurt is a digital strategist and IT professional blending emerging technology with practical application to help businesses and individuals streamline their digital presence. His current work focuses on the intersection of intentional living and technological resilience, exploring how individuals can leverage modern tools to navigate the second half of life with purpose.