Dry eyes at the computer: why it happens and what helps

By the middle of the afternoon your eyes feel gritty, hot or heavy, and rubbing them helps for about a second. Dry eyes at the computer usually come down to two things working together: you blink less, and less completely, while you concentrate on a screen, and the air around many desks is dry or moving. The tears coating the front of each eye evaporate faster than they are topped up.

Most of the fixes are changes at the desk: blinking on purpose, looking away regularly, getting moving air off your face, adding some moisture to a dry room and lowering the screen a little. If the dryness keeps coming back anyway, or comes with pain or changes in your vision, that is the point to see an optometrist.

What is actually drying out

What keeps the front of each eye wet is the tear film, a coating much thinner than a sheet of paper. It keeps the surface of the eye smooth, which you need for clear vision, and it is refreshed every time you blink. Each blink spreads a fresh coat across the eye. Between blinks it slowly thins and evaporates. An oily outer layer, made by tiny glands along the edges of your eyelids, slows that down.

When the film breaks up before the next blink arrives, small dry patches form on the surface. That is what you feel as grit, burning, or the sense that there is something in your eye. Your vision may smear for a moment and clear when you blink.

One thing surprises people: dry eyes can also water a lot. An irritated eye can set off a rush of reflex tears, thin and watery ones that run off instead of coating the surface. So streaming eyes at the end of a screen day do not rule out dryness.

Why a day at the desk makes it worse

You blink less, and only halfway

Concentration slows blinking. Studies of people reading or working at screens have generally found that they blink less often than they do in conversation, and that more of their blinks are partial, with the upper lid stopping short of the lower one. The blinks you skip are coats of tear film the eye never gets. There is more on this, and on how to do a proper blink, in why you blink less at the computer.

Your eyes are open wider

When you read a book, you look down and your upper lids drop to cover more of each eye. A screen at eye level or above keeps your eyes wide open, so more of the surface is out in the air. Tall external displays and laptops raised high on a stand both do this.

The air is dry, and it moves

Air conditioning dries the air in summer and heating dries it in winter. A room can feel perfectly comfortable and still be dry enough to bother your eyes. On top of that, air often moves across a desk without you noticing: a ceiling vent above your chair, a heater by your feet blowing upward, a desk fan on a hot day, the exhaust from a computer or a nearby printer. Your skin may not register a draft. A film of tears a few thousandths of a millimeter thick does.

Contact lenses

A contact lens sits inside the tear film and splits it into a layer in front of the lens and a layer behind it. Many lens wearers find their eyes feel drier on long screen days and worse toward the evening, when the lenses have been in for hours.

Other things that can play a part

Dry eye becomes more common as people get older, and some medicines, hormonal changes and health conditions can contribute too. You do not need to work out which one applies to you. It is one more reason to mention the dryness to a pharmacist or a doctor if you take regular medicines, and to get checked if desk changes do not help.

Desk changes that help

None of these is dramatic, and you don't need all of them. Start with the ones that match your desk.

Blink on purpose a few times an hour

Close your eyes slowly and fully, as if you were about to fall asleep, pause for a second and open them. Do it three or four times. The goal is a complete blink, upper lid all the way down to the lower one, which spreads the tear film properly and squeezes a little oil from the glands along the lid edges.

Look away regularly

Short breaks give your blink rate a chance to recover, because blinking tends to return to normal as soon as you stop reading. The 20-20-20 rule is the easy version: roughly every 20 minutes, find something 20 feet away and rest your eyes on it for 20 seconds. Closing your eyes for a few seconds during that break helps too.

Get moving air off your face

Spend one minute finding where the air around your desk comes from.

• Look up. If there is a vent above or in front of your desk, turn its slats away from you, or move your chair or desk a little out of its path.
• Point a desk fan at your body or the wall, not at your face.
• Turn a heater at your feet so it blows across the floor, not up toward your head.
• At home, notice whether your desk sits right next to a radiator or an air conditioner and move it if you can.

Add some moisture to a dry room

If the room feels dry, especially in winter with the heating on, a humidifier can help. Keep it clean, following the maker's instructions, because a neglected one can grow mold. In an office where you do not control the air, the other changes on this list matter more.

Lower the screen a little

Set the top edge of the screen around eye level or a little under it, so that your gaze dips a touch to reach the middle. Your upper lids then cover more of each eye. For a laptop on a stand, this usually means a lower setting than you might pick. About an arm's length away is a good distance to start from.

Go easy on your lenses on long screen days

Stick to the wear time and replacement schedule your optometrist gave you, wear glasses for long evening sessions, and replace the lens case regularly. If your lenses feel dry most days, tell your optometrist. There are different lens materials and care solutions, and they can suggest what might suit you.

Try not to rub

Rubbing feels good for a moment, but it can irritate the surface further and, if you wear lenses or have unwashed hands, bring dirt into the eye.

A word on eye drops

Many people reach for eye drops first. There are many kinds, and which one suits you, if any, depends on what is causing the dryness and whether you wear contact lenses. Ask a pharmacist or an eye doctor before you choose one, and mention it if you find yourself using drops many times a day.

When to see an optometrist

Mild dryness at the end of a long screen day is very common. Book an appointment with an optometrist or an eye doctor if any of these apply:

• The dryness has not improved after a couple of weeks of the changes above.
• Your eyes hurt, rather than just feeling tired or gritty.
• They stay red, or there is discharge or crusting along the lids.
• Your vision stays blurred after you blink, or light has started to bother you.
• One eye is much worse than the other.

If you wear contact lenses and an eye becomes red and painful, take the lenses out and get it looked at promptly, the same day if you can.

An optometrist can examine the tear film and the edges of your lids, tell you whether this is dry eye and what kind, and suggest what to try. They will also check your prescription. An out-of-date one makes screen work harder, and it can creep up without you noticing.

Letting your Mac do the noticing

The trouble with dry eyes is that you only notice them after the fact. Nobody feels their blink rate dropping. You feel the grit an hour later.

A prompt from outside your own head catches it earlier. Notchpals' Eyes characters, Blip, Bill and Blush, bring two moments that suit dry eyes. One is a blink break: a request for a few slow, complete blinks and nothing else. The other is an eye break, a short look across the room in the 20-20-20 spirit. Your crew has one of the three. Here is Blush on the blinking:

BlushBlink slowly with me? I'll go first. Don't watch. Okay, now you.

Press Done after the blinks. If you are in the middle of something, Later moves the visit 20 minutes down the road, once. These visits come out of a daily allowance that all your crew's repeating reminders share, Calm, Normal or Chatty, and even on Chatty they are spaced well apart. So the blink habit from earlier in this post still does most of the work, and the visits keep it from fading. Notchpals can't see your eyes, so it takes your Done on trust. It can't turn the air vent away from you either, so do that part today.