Looking after your eyes with long screen hours

Screens make you blink less

Concentrating on a screen cuts your blink rate to under half its normal level. The tear film dries, producing grittiness and stinging, which is a large part of what people call eye strain. Blinking deliberately helps, as does placing the screen slightly below eye level so the eyelids open less. The more absorbing the screen, such as games or videos, the less you blink, so closing your eyes for a few seconds now and then during long sessions already makes a difference.

What 20-20-20 actually does

Every 20 minutes, look at something about six metres away for 20 seconds. Sustained close focus keeps the focusing muscle contracted; looking far releases it. It is hard to remember without a timer, so setting a reminder is worth it. Look at something genuinely far away, such as the view outside; staring at a wall in the same room may not relax the focusing muscles enough.

• Set a reminder every 20 minutes
• Look out of a window or down a corridor
• Hold the distant focus for 20 seconds
• Standing up adds a stretch to it

Match brightness and contrast

A bright screen in a dark room keeps your eyes adapting, which tires them. Matching screen brightness to the room is the basic fix. If small text makes you squint, increasing text size helps both your posture and your eyes. Text with too little contrast against the background also tires them faster. Screens that flicker at low brightness can tire some people more, so if another screen feels noticeably easier under the same conditions, the device itself may be the difference.

About blue light

Evidence that blue-light filtering reduces eye strain is weaker than commonly claimed. What is reasonably clear is that bright screens at night push your sleep rhythm later. Night mode is better understood as a sleep measure than an eye-health one. At night, lowering overall screen brightness makes a bigger difference than night mode alone.

Screen and desk layout

Eye strain often comes less from the screen itself than from where it sits. A screen that is too close keeps the focusing muscles tense, and facing or sitting with your back to a window leaves your eyes fighting glare and brightness differences. The guidelines below are a starting point rather than a rule; adjust gradually toward what feels comfortable.

• Distance: about where your fingertips reach with your arm extended
• Height: the top of the screen at or slightly below eye level
• Place windows to the side of the screen to avoid glare and backlight
• Do not use a screen alone in a dark room; switch on room lighting too
• Keep air from heating or air conditioning off your face

Habits that reduce dryness

Much of the gritty feeling comes from the tear film drying out. Besides blinking deliberately, a humidifier in dry seasons and keeping airflow away from your eyes both help. If you wear contact lenses during long screen sessions, your eyes dry out more easily, so set aside time without them. Artificial tears are a handy aid, but if you need them often, reduce the causes first, and if it continues, ask an eye doctor which product and routine suit you.

Common mistakes and a checking order

When their eyes feel tired, many people rub them or turn brightness all the way up to see more clearly; both make strain worse. It is also common to keep wearing glasses from several years ago and blame the screen alone. Vision changes slowly, which makes it hard to notice yourself. Check in a simple order: first screen brightness and text size, then screen distance and position, then your break habits. If nothing improves after two or three weeks, get your eyes tested.

When to see an optometrist

Pain lasting days despite rest, part of your vision being blocked, sudden changes in sharpness, or worsening glare may not be a usage problem. Eyes are a poor organ to wait out, so have these looked at promptly.