Foreword
Eye strain (or asthenopia) and “Computer vision syndrome” are probably familiar to most of heavy computer users: the symptoms include red, dry, or sore eyes, eye pain, and a bunch of others, not obviously related to eyes ones. We will go through a few causes and ways to reduce it.
The material comes from years of observation and occasional topical reading. Not much of sources is linked here, but other articles on this topic can easily be found.
CRT monitors
Fortunately, CRT monitors are not used much these days, yet if you happen to own and use one – that may be the cause. The solution here is simple: switch to an LCD monitor.
Glare
It is both annoying and harmful. There is a few ways to reduce it, but one of the most straightforward and reliable ones it to get rid of all the light sources – except for the monitor itself, of course.
Brightness and contrast
Here is a simple and important one: since you basically stare at a lamp all the day long, which obviously is not nice, it often helps to reduce its brightness – one of the basic monitor settings. Though it may become harder to read (which is bad for several reasons) with reduced brightness, and then you will need to increase contrast in order to compensate it.
But if your room is brightly lit itself, then having higher brightness may be a good thing; basically, it should match the environment.
Color themes
Colors are somewhat complementary to brightness: dark background reduces overall brightness, so dark color themes are often preferred. But again, it may differ depending on environment: light ones may be more suitable for daytime.
Contrast is primarily determined by colors. This WCAG recommendation links some examples where you can observe how it works, while the recommendation itself explains how and why to keep the contrast high.
Yet, do not jump into extremes: too high contrast (black on white, white on black) is another possible reason of eye strain. Picking pastel colors is a safe option in most situations; or, at least, replace black with dark grey, and white with light grey or yellow. By the way, warm colors are considered to be nicer for eyes.
Blinking and taking breaks
Eyes get dry if you are not blinking, and it is said that people tend to blink less when they are doing their computing. It is also not particularly healthy to stare at the same object and to sit all the time, so taking breaks is a useful thing to do. The problem with it is that not everyone likes to interrupt what they are doing in order to take some silly break. One solution would be to take breaks not regularly, but at least occasionally: instead of procrastinating in front of a computer, catch a cat, grab a coffee, take a nap, or even do some physical (which may also be helpful to relieve stress) or eye exercises.
Bias lighting
Bias lighting is praised by some folks. It is about placing a light source behind your monitor – so that there is no glare, but you do not stare at the only lamp in a dark room, since there is some ambient light.
Fonts
Last but not least, fonts are important for comfortable reading. It is useful to configure the following things in your terminal emulator, text editor, and web browser:
- Font size: unfortunately, many websites will not respect it, but it should be large enough to be comfortable to read all the day – that is, larger than the minimal size suitable for reading.
- Arguably, sans serif fonts (the ones without serifs) are more suitable for reading from a screen.
- Easily distinguishable letters would not harm: “1lI” and “O0” should not make you to focus more than usual, for instance.
- Subpixel rendering and hinting should be configured and work appropriately. It usually is not a big problem on major GNU/Linux distributions these days, yet one may observe them being terrible from time to time, which may be caused by poor fonts or poor configuration.