Ergonomics: Reducing Eye Strain

I often brag to my close friends I have 20/10 vision. This means that I can see things about 10 feet (ca. 3 m) further away than people with perfect 20/20 vision can. I want to continue bragging about this, so as a Software Engineer that admittedly spends much of my free time on screens, I gotta make sure I protect my eyes as much as possible!

Fear Mongering and Ergonomics

First and foremost, I do not want to fear monger. I personally have health anxiety and get too stressed when I hear about people's health optimizations. If you don't find yourself making every ergonomic decision possible, you're fine. I do not want to claim that if you make these adjustments, your eyesight will be saved, nor do I want to claim that if you do not make these adjustments, your eyes will be doomed.

However, I do want to claim that making some of these adjustments will make for a more comfortable experience. With the amount of time that we spend on our devices, I believe that making the experience as comfortable as possible is essential. Go ahead, try to argue that we shouldn't try to increase our physical comfort!

Increase your Default Font Size

I make it a point to increase the default font size on just about every app I use: my terminal, Firefox, Microsoft Teams, even the Mincraft chat dialogue.

"But I can already see with the default font!"

Yeah, I know. I can too, and so can most people. That's why it's the default font. However, whether or not you are able to see does not necessarily imply comfort. Comfort is actually correlated with "visual acuity."

Visual Acuity

Visual Acuity is defined as the sharpness of vision. It is measured by your ability to discern letters at a given distance according to a standard. When I said I had 20/10 vision, that was my visual acuity. It means I can see at 20 feet (ca. 6 m) what normal people would need to be 10 feet (ca. 3 m) away to see. So, how does visual acuity come into play?

Mark Rosenfield, a researcher at SUNY College of Optometry, focuses on Computer Vision syndrome, or digital eye strain. In his article published in Volume 17 of Optometry in Practice, he finds that the visual acuity demands when looking at a web page on a smartphone can range from about 6/6 to 6/29 with a mean of 6/15. This means that the average smartphone web page requires you to see at 6 feet (1.83 m) what it takes the average person to see 15 feet (4.57 m) away. This may sound like you're covered in most cases, but Rosenfield highlights that acuity reserve is required to allow comfortable reading for an extended period of time. In fact, studies show that two-times acuity reserve is appropriate for young, visually normal subjects when reading from a laptop. In other words, the text should be at least twice the size of what you're capable of reading. The acuity reserve rate only goes required for a comfortable reading experience only increases with age and demand of the task.

If I want to have a comfortable browsing experience, whether at work or at home, I need to increase default font size. There's some overhead in setting this up, obviously, but it's worth it. You only have to do it once! If you want to try it out, I recommend increasing the zoom size of your browser. I've found success increasing from 100% to 120%.

Reduce Blue Light

Get f.lux (it's free)

I cannot recommend f.lux enough. I promise there's no affiliation here, I'm not big enough for something like that. If you don't know, f.lux reduces the blue light on your computer. This will give your computer a more yellow or red tint. It's incredibly easy to set up. Once you download it, its default settings will adjust to the time of day and reduce your computer's blue light to mimic the rhythm of the sun. I have customized the settings to reduce my blue light throughout the entire day and have turned up the intensity to the highest setting. It may feel weird at first, but you get used to it in no time. Note that I turn f.lux off while I watch movies and play games if it's not too late so that I can appreciate the visual medium!

Increase your Sleep Quality

I'm guilty of using my devices before bed. In an ideal world, I'd like to cut them out completely a few hours before bed... I've switched to using board games and physical books as my nighttime activities. This has helped a bit, but I'll still message my friends at night, work on side projects, or even doomscroll. While f.lux doesn't completely alleviate the impact of screentime on your sleep quality, it has been shown to help. This is because night-time exposure to blue light affects our circadian timing. Our bodies are biologically programmed to believe that since there is blue light, the sun must be out. As a result, the quality of our sleep is disrupted. If you want to read more about why you should increase sleep quality, I recommend sleep professor Matthew Walker's book: Why We Sleep, or at least read Bill Gates' takeaways from it.

Use Dark Mode (Maybe)

I have found that my eyes feel better when I have dark mode on. It makes text easier to read, and again reduces blue light. There are many plugins that allow you to turn on dark mode on every site. I downloaded Dark Reader for Firefox and have had a generally positive experience with it. There are some sites where the css becomes a little goofy, so I'll toggle the plugin for those sites and add them to the exception list. You can go as far as customizing css for certain sites, but I haven't used that feature at all.

Caveat: Researchers are Split on Dark Mode

While dark mode makes text more legible, and decreases blue light, it heavily depends on your physical environment; it seems to be the most effective when working in low-light environments. Researchers seem to be split on the overall effectiveness of dark mode. According to the paper linked above, recent studies show that dark text on a light background is actually more beneficial when your goal is to read text on a computer screen. This is because positive contrast results in a smaller pupil size, increasing retinal image quality and depth of field.

It appears that using dark mode is a trade off between blue light and visual acuity. I am no eye doctor, so take this with a grain of salt. Here is what I've gathered: Dark Mode should be used at night to reduce blue light, but dark mode can be turned off if you are in a well-lit area. I personally assume that bringing up my default font size accounts for the decrease in visual acuity that comes with dark mode, but I have nothing to support this.

Do What Feels Best

This is the most important part. Do what feels right to you. If dark mode doesn't feel good to you, don't use it. The same goes for all these other adjustments I've mentioned. Of course, I recommend you try some of these and give it a few days to see if you adjust to it. The ultimate goal here is to increase your comfort, so if you're not comfortable, what's the point?

If you care enough about your health to seek out and read something like this, you're probably doing enough to maintain a healthy lifestyle. Thanks for reading, and feel free to reach out to me.