How often should you blink, and what screens do to it
By Ally Daoud, Australian Optometrist and Dermii Co-founder
The short answer
A normal blink rate is 12 to 15 blinks a minute. Looking at a screen drops it to 5 to 7. Every blink presses the glands along the edge of your eyelid and releases a small amount of oil onto the eye, so fewer blinks means less oil. That is why eyes that feel fine at 9am feel gritty by 3pm.
Before you read on, count your blinks for the next minute. Most people are surprised.
How many times should you blink per minute?
12 to 15 a minute is the usual range. Some people sit a little either side of it and that is normal.
You do not decide to do it. Blinking is automatic, in the same way breathing is, and like breathing it changes depending on what you are doing without you noticing. Reading slows it. Concentrating slows it. Driving at night slows it.
Over a waking day that adds up to somewhere around fifteen thousand blinks. Each one takes about a tenth of a second, which is why you never perceive the world going dark.
What happens to your blink rate on a screen?
It falls by roughly half, to 5 to 7 a minute.
This has been measured many times and the finding is consistent. The more concentrated the task, the fewer the blinks. Reading a document, scanning a spreadsheet, following a video call. Anything that holds your attention holds your eyelids open with it.
A screen makes it worse in a second way. Screens tend to sit slightly above eye level, especially a desktop monitor, so you look up rather than down. Looking up opens the eye wider and exposes more surface to the air, which means more evaporation from a tear film that is already getting less oil.
So the two effects stack. A wider open eye, and a third of the usual oil supply, for eight hours.
Why does blinking matter for dry eyes?
Because the blink is the delivery system.
Along the edge of each eyelid, at the base of the lashes, sit around thirty small glands. They hold oil, and that oil forms the top layer of your tear film. Its job is to slow the watery layer underneath from evaporating. What your tears are actually made of.
The oil does not seep out on its own. When your lids press together they squeeze the glands, a small amount of oil is released onto the lid margin, and the upward sweep of the blink spreads it across the eye.
No blink, no squeeze. No squeeze, no fresh oil.
There is a second job too. Blinking sweeps debris off the surface of the eye and towards the inner corner, where it drains away. Fewer blinks means more of it sitting there.
What is an incomplete blink?
A blink where the upper lid does not quite reach the lower one.
It sounds like a small thing and it is surprisingly common on screens. Estimates vary but a significant share of blinks during focused screen work are partial rather than full. Your lid comes most of the way down, then goes back up.
Two things follow. The glands along the lower lid margin never get properly pressed, so less oil comes out of them than out of the upper ones. And the lower part of the eye, the strip that never gets covered, dries out more than the rest.
If your eyes feel worse across the bottom, or you notice the discomfort sitting low, incomplete blinking is worth considering.
You can feel the difference yourself. Close your eyes gently, as if falling asleep, and hold for a second. That is a complete blink. Most people notice immediately that it is not what they have been doing at a screen.
Why do my eyes get worse in the afternoon?
Because it is cumulative.
You start the morning with a tear film that has been left alone overnight. Through the day, at roughly half the oil supply you should be getting, that film gets progressively less stable. It breaks up faster between blinks, and the gaps where the surface is exposed get longer.
By mid afternoon the difference is enough to feel. Gritty, heavy, like sandpaper, burning by four. It is not tiredness and it is not in your head. It is a supply problem that has been building since you sat down. More on the afternoon dip.
Can you train yourself to blink more?
Partly, and it is worth doing, but be realistic about what it achieves.
Deliberate blinking works while you are paying attention to it and stops when you go back to concentrating, which is most of the day. A reminder on your phone or a note stuck to the monitor helps more than willpower.
What helps most is the complete blink rather than the count. Two or three deliberate full closes, holding each for a second, a few times an hour. You are aiming at quality rather than quantity.
The honest limit is this. Blinking more moves whatever oil is available to be moved. If the oil in those glands has thickened over years, better blinking will not soften it. That takes sustained warmth, from something like a self-warming mask, and the lid margin has to be clean enough for the oil to have somewhere to go. On warmth and on cleaning the margin.
Blinking well keeps a working system working. It does not restart one that has been sluggish for a decade.
When to see an optometrist
Book a proper look if you have eye pain, sudden vision changes, light sensitivity, coloured or sticky discharge or if one eye is clearly different from the other.
Worth booking too if you have been uncomfortable for months without improvement, or if you find it hard to close your eyes fully. There is more that can be assessed in a chair than at a desk.
Frequently asked questions
How often should you blink per minute? A normal blink rate is around fifteen blinks a minute, though anywhere from twelve to twenty is common. Over a waking day that adds up to roughly fifteen thousand blinks.
How much does screen time reduce your blink rate? By roughly two thirds. Blink rate drops from around fifteen a minute to about five during concentrated screen work, and the more absorbing the task the fewer the blinks.
Why does blinking matter for dry eyes? Blinking is what releases oil from the glands along the edge of the eyelid. That oil forms the top layer of the tear film and slows evaporation. Fewer blinks means less oil reaching the eye.
What is an incomplete blink? A blink where the upper lid does not fully meet the lower lid. The glands along the lower lid margin are not properly pressed, so they release less oil, and the lower part of the eye surface dries out more than the rest.
Can blinking exercises help dry eyes? They help move whatever oil is available, and complete blinks matter more than frequent ones. Blinking will not soften oil that has already thickened in the glands, which needs sustained warmth and a clean lid margin.
Why are my eyes worse in the afternoon than the morning? The effect is cumulative. A reduced blink rate across a working day means the tear film gets progressively less stable, so discomfort builds through the day rather than arriving at once.
Keep reading
- What your tears are actually made of
- Does a warm flannel actually work?
- Why are my eyes worse in the afternoon?
About the author: Ally is a practising optometrist in Australia and the co-founder of Dermii, an Australian lid-hygiene brand. The information in this article is general and is not a substitute for clinical advice. If you’re concerned about your eye health, please see your optometrist or GP.
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