On an average day, I spend my working hours in front of a computer monitor and when I head home, it’s gaming time. My eyes don’t get a break from the flicker of electronic screens which is why I pay particular attention to the refresh rate of my monitors because having a monitor with a higher refresh rate really cuts down on eye strain.
A higher refresh rate results in a smoother screen that's more gentle on the eyes. If you're trying to reduce eyestrain then a monitor refresh rate of 120Hz is best. A higher-end 144hz or 240hz monitor wouldn't be necessary for eye health but would further increase frames per second and overall display smoothness.
If you’re more of a gamer and less of a tech nerd like me, you may be wondering why a higher refresh rate is easier on the eyes. Hey, you might be wondering what a refresh rate is, so let’s start at the beginning…
What is a refresh rate?
A refresh rate is measured in Hz or Hertz. Hertz is a frequency, so it refers to how many times per second something occurs. In the case of a refresh rate, Hertz refers to how many times the picture on that television screen refreshes to show a new picture.
So, if you have a movie shot at 24-frames-per-second, you want a television that can display at least 24-frames per second. Incidentally, this won’t be a problem – most televisions today refresh at 60 or 120 Hz. This means that they are capable of refreshing the picture on the screen 60 or 120 times so they can display a maximum of 60 or 120 frames per second.
Frames per second and Hz
Many decades ago movies used to be called “moving pictures” and that is essentially what they are – a series of pictures one after the other. These pictures are captured by a camera at a specific rate – so a video camera that records a Hollywood movie may capture 24-frames-per-second.
At 24-frames-per-second the movie camera is taking twenty-four snapshots every second and when those snapshots are strung together, they create a “moving picture.”
Now, a camera must take a specific number of frames per second to create a smooth moving “movie” otherwise you would see the equivalent of an electronic flipbook.
The frames per second are what determine how many frames get sent to the screen when the film is displayed. So, a film shot at 24-frames-per-second is only ever going to be able to display a maximum of 24-frames in a second.
To get the best picture possible when you watch that movie, you want a television that can display at least 24-frames-per-second.
Now, when shopping for a television to watch your movie on, you aren’t going to find a television that advertises frames per second, you are going to see what is called a “refresh rate.”
What happens if refresh rate is lower than frames per second?
While we rarely experience problems viewing movies on our television screens, video games today are designed to hit a minimum frame rate of 60-frames-per-second, but they often exceed this.
So, what happens if you have a monitor that has a 60Hz refresh rate but a video game that runs at 120fps?
To get the most out of your video game, you need a monitor that is going to refresh 120 times per second – a 120Hz monitor. With a 60Hz monitor, you are going to get half the amount of frames per second displayed.
Imagine your video game as that series of moving pictures, only this time, you only get to see every other picture. When every other picture is threaded together and displayed, you wind up with a very choppy picture.
This is exactly what happens when you use a monitor with a low refresh rate to play a game with a high number of frames per second. Your picture is not fluid because you are missing half of the information. Think back to the flipbook I mentioned before, this is an exaggerated example but is much easier to visualize.
Now, if you have a monitor with a 120Hz refresh rate, you will see every frame of the film which means that your picture is smoother and flows together flawlessly.
How does refresh rate affect your eyes?
So how does this all affect your eyes?
It is generally believed that the average human eye takes in and processing at a rate of 60 frames per second, although this varies individually with some people taking in more and some less - there is some debate about whether 60 frames is the rate since people have proven your eyes can detect changes at higher frame rates of higher than 100 frames per second
Since we can take in 60-frames-per-second as a base, when we view something that is displayed at a slower rate, we tend to feel slightly disoriented as our brains struggle to put together the movement of the pictures and fill in the gaps between pictures.
Have you ever watched people dancing under a strobe light? Strobe lights work similarly.
A strobe light that runs at 10 Hz is showing far fewer frames per second than our eyes are capable of taking in. So when the light flickers at 10Hz, everything we see becomes choppy like a stop-motion film. We can start to feel disoriented as our brains work to fill in the gaps or the “frames” that we aren’t seeing that we think should be there.
This is an extreme example because we’re not playing video games shot at 10-frames-per-second, but the principle remains the same. Lower refresh rates force our brains to work harder to fill in the gaps and our eyes strain because we are actually seeing pictures refresh rather than seeing fluid motion.
Video - How many Frames-per-second (FPS) can you eye see?
If the human eye takes in 60 FPS, Why do we have 120Hz monitors?
If the average number of frames per second that the human eye can see and process is 60, why would we need a monitor or television screen that refreshes an image more than 60 times per second?
Firstly, the average FPS that the human eye takes in and processes is 60, some people can see more and some who see less. For those people capable of seeing more than 60FPS, the difference between 60Hz and 120Hz is distinct.
Secondly, even when we are only able to consciously process 60 frames per second, we are still able to take in frames beyond that on an unconscious level.
What does that mean exactly?
It means that when your video game streams at 120 frames per second, you may be consciously taking in and processing 60 frames every second, but the other frames that you are not consciously processing are still providing your brain with cues (or information) that can help to process the big picture.
Is there a big difference in how we see a video game on a monitor that has a 60Hz refresh rate vs 120Hz refresh rate?
This goes back to the question above. Some people are going to notice a much bigger difference between these two refresh rates if they can process more than the average 60 frames per second. Even those people who cannot process more than 60 frames per second will notice a difference in how smooth the picture is, though.
Video - 60hz vs 144hz vs 240hz refresh rate monitors
Is it always best to get the highest refresh rate possible on a monitor?
The answer to this question depends on what you are going to use your monitor for. Let’s look at some examples…
During the day, I am a graphic designer, having a monitor that refreshes at 120Hz makes little difference to me because I spend most of the day looking at still pictures. Yes, my picture is crisp and clear, but it is also crisp and clear at 60Hz for the type of work that I do.
Fast forward to night time when I am gaming. Playing a game of COD at 60Hz is doable, but try playing it at 120Hz and you will notice the difference that you didn’t know you were missing. The picture is much sharper, the blurriness while moving quickly is a thing of the past, and the image that you get on the scope of your gun is something else entirely.
What I mean to say is that if you spend most of your time working on your monitor doing graphic design, coding, or even just surfing the web, you’re not likely to notice a huge difference between a 60Hz refresh rate and a 120Hz refresh rate.
If, however, you are playing a fast-paced game or a game that was optimized for 120 frames per second, the difference in refresh rate is more than noticeable. Your brain is being fed more information about your surroundings and your eyes are straining less to take in details.
Not sure whether refresh rate will make a difference to how you see your favorite game? Try using a 60Hz monitor, boot up your game and spin your character in circles while trying to keep a clear view of your environment. There is a lot of blur and tearing.
Now, do the same thing using a monitor with a 120Hz refresh rate. As you spin your character this time, you will notice much less blurring and will feel much less like the environment is trying to catch up with you as you move.
What about refresh rates higher than 120Hz?
The Asus ROG Swift monitor has a refresh rate of 360 Hz. Is this refresh rate worth investing in?
No…not yet, anyway. Virtually every game on the market falls at 60 FPS to 120FPS. A 360Hz monitor is not going to be able to give you any more frames per second than the game has. That said, when 360 FPS games do become the “next big thing,” a 360Hz monitor will offer a very subtle benefit over a 240Hz monitor, and for some, the difference will be imperceivable.