Vision info

Binocular vision
It seems that in many cases bad tech triggers binocular vision problems.
It doesn't matter if you ever had any binocular vision problems or if your vision is perfect. Bad tech (or bad lighting) may interact with binocular vision, either causing additional troubles to people who have underlying problems or casing troubles to people who have perfect vision.
A very simple binocular vision self-test is a Brock string test. You can test yourself before an eyestrain and in the middle of it to understand what's going on. Brock string can also be a basic exercise.

If you suspect some underlying binocular vision problems you may consult with an optometrist and try:

Helpful links:

If your core problem is bad tech and not an underlying condition, they can help you only partially (or not help at all). Patching one eye has the best chance to lessen tech influence.

Exercises and lens are not a cure if you never had any binocular vision problems. In that case, you better avoid bad tech and track your health with the Brock string test. You also can do exercises to help you get rid of symptoms faster, but be careful. Avoid overdoing them and avoid doing any exercises through pain, in some cases, it can make things worse: the bad screen will overwork your eye muscles and exercises/lens can overwork them additionally (example).

Please note that tech can affect your light sensitivity, lead to red eyes, etc. Track your eye health during exercises and patching. If you notice that your eyes or one open eye have increased light sensitivity, a lot of new visible blood vessels on the conjunctiva, or signs of inflammation (post with example), consider avoiding the bad screen.

Just to double-check: check your prescription glasses
If you wear prescription glasses/contacts and you have troubles not only with some screens but also with different activities that involve focusing, double-check your prescription.
Sometimes a mistake as little as 0.25 can lead to a lot of troubles: thread

13 days later

List of image, signal, source, flicker related problems for monitors and laptops

1. PWM
Severe stroboscopic full-screen flicker, typically invisible (but easily detectable)
Article about PWM on notebookcheck
Iris - software that emulates DC dimming, equalling PWM to that is used for 100% brightness on your device
An old and experimental tool to adjust PWM driver frequency on Windows
IEEE Std 1789-2015 - recommended practices for PWM (pdf)

2. Vcom (LCD screens)
Small flickering of separate pixels, visible with bad factory settings
Article about Vcom
Post about Vcom on IXBT with flicker sample (Russian)

3. Inversion (LCD screens)
Small flickering of separate pixels, visible on test images
Inversion tests (should be displayed without any scaling in browser or OS, 1:1 ratio):
http://www.techmind.org/lcd/index.html#inversion
http://www.lagom.nl/lcd-test/inversion.php
Post about inversion leading to real life visible patterns
Post about inversion leading to real life visible colored spots (Russian)

4. Temporal dithering
Small flickering of pixels to create a color, potentially visible
Article about dithering with link to example (Caution! Severe flicker!)
More detailed article with examples
Another article that has advice on where to find dithering setting for Nvidia and AMD
Guide how to check whether dithering is affecting you and turn it off on Intel video cards (Russian)
Solution for temporal dithering from si_edgey
Post with a hardware and software setup to overcome dithering
Disabling dithering on Linux with Nvidia
On laptops, discrete GPU passes its output to the integrated GPU, so it has the final say on dithering or processing
Ditherig, software to turn off dithering: home page
Ditherig source code
You can find more about how to disable dithering through the forum search.
Dithering tests and capture:
By Seagull I have bought a capture card
By Seagull GPU dithering (Important findings: dithering frequency depends on the color and also dithering may disappear on some output modes of specific GPU)
By andc Screens under microscope in slowmo (dithering / FRC tests)
By ShivaWind Video of undefined dithering-like flicker, made visible with e-ink (scroll through user posts for more info)

5. FRC
Small flickering of pixels to create a color, potentially visible
It is a form of temporal dithering that is tied to the matrix and is used to increase matrix color capacity.
Data about many matrices can be found here:
http://www.tftcentral.…onitor_panel_parts.htm
http://www.panelook.com/modelsearch.php?op=size
How to check panel manufacturer on MacBook

6. Cables
Can create noise or artifacts on image. Also connection port can affect how a GPU will process a signal.
HDMA cable
Post about symptoms from a specific HDMI cable
Visible flicker from a malfunctioning HDMI cable (Russian) - this post was originally on ledstrain but I can't find the original one
Post about HDMI cable influence on eyestrain (Russian)
VGA cable
Post about VGA cable flicker
Conversion cables
Post about yellow tint with conversion cables

7. Image output
Post where eyestrain decreases with 16-235 range
Two examples of eyestrain or discomfort from different color range settings (Russian)
Post where 16-235 helped to eliminate eyestrain completely
Article about 16-235 and 0-255 (Russian)
Nvidia drivers automatically interpret monitor as TV when it is plugged in through HDMI and gives it 16-235 range (dated 2015) (Russian)
Image output and dithering:
GPU dithering (Important findings: dithering may be absent with some image output modes)

8. Image resolution scaling
Scaling algorithms make an image blurry
A big and very detailed article about scaling

9. Software and OS
Might be connected to dithering, color output, or other things that are hard to figure out
Detailed article about eyestrain from Linux (Russian)
Thread about eyestrain from linux, where disabling dithering does not fix the issue
Windows 10 anniversary edition (1607 and later) thread
Thread where rebooting Windows 10 in audit mode helped
Chrome thread

10. Visual effects in software
Chromatic aberration in games:
Thread about one game on Reddit
Few other visual effects in games
Factorio: headache and eye pain

11. Anti-aliasing, font smoothing
ClearType on Windows
Debian: https://ledstrain.org/…-rendering-eyestrain/8
Post about anti-aliasing influence on headaches, Ubuntu

List of light, backlight, screen parts related problems for monitors and laptops

It is worth mentioning that a single monitor or laptop model can have different LCD panels within, provided by different manufacturers. They will look similar and have the same specifications on paper but will have differences.

1. Undefined problem X (light that affects vergence).
Presumably connected to inner screen parts.
A very detailed post about this problem on smartphones
Hypothesis here
Post where removal of BEF (or similar) layer reduced symptoms with 5 screens
Post where a change of polarizer and BEF removal helped partially

2. Excessive blue light
There are some reports that reducing blue light helps, but sometimes not for 100%.
To limit the blue spectrum from the entire screen - optics have glasses with a blue-blocking filter. Notice that filters vary in intensity.
Post about blue light blocking glasses success
Blue light test for glasses

3. Rough matte coating
Up to personal preferences. Sometimes can cause more than discomfort.
Post about discomfort
Another post about strong discomfort
And another post about strong discomfort (Russian)

4. Screen is too glossy
Up to personal preferences. Sometimes can cause more than discomfort.
Post about severe discomfort (Russian)

5. Minimal brightness is too high
It can affect you if there's not enough lighting in the place where you use a monitor, or if you work at night/without light.
Windows:
Dimmer - download link and also author's story about eyestrain when working at night.

Slacor This thread is anyway created for further systematization and sort of a wiki workgroup, so I will post here also wiki questions.
For now created two pages in links: about smartphones and about monitors.
Questions:

  1. I am not sure where is the correct version of markdown. Rich text in the editor on the right shows a very different page compared to the preview window on the left. For now I formatted pages based on the editor.
  2. I am not sure it should go under the links section.
  3. Other sections that I wrote here are most definitely not for the links section.
    Maybe we will work with @logixoul on wiki filling and will figure out where to place those pages or that info in the process.

      List of theories will be in another thread.

      Notice: sensitivity to one kind of flicker doesn't make you automatically sensitive to other flickers.
      Flickers are very different, they have different parameters and different levels of visibility.
      Random examples:
      Post where a person is sensitive to dithering that can be disabled by ditherig, but not sensitive to 200 Hz PWM (Russian)
      Post where a person is sensitive to different sources of signal (OS, GPU), but not sensitive to PWM, and all his safe screens have easily detectable PWM (Russian)

      This is also true for every other problem mentioned here: sensitivity to one does not automatically mean sensitivity to others.

      dev