Here is the link to the article mentioned.
The Interesting Case of LCD Screens and Post Concussive Headaches

This article is not entirely correct. A properly functioning LCD screen does not flicker. LCD pixels are either on or off. CRT (old TV Tube) screens flicker because each pixel lights up then fades before lighting up again. This is the source of flicker. Screen brightness can be a problem and can be easily changed on most laptops and on desk displays through settings or with f-lux, a free software program.

An issue that can be a problem for some is line length. 45 to 75 characters is considered a comfortable line length. 66 characters of letters and spaces is considered ideal. Many web site use a line length of up to 120 characters or more, making it difficult to follow from line to line. A browser window can be made narrower to shorten lines if the web page uses automatic line break.

Horizontal gaze (nystagmus) can impact reading effort as it changes how the eye moves from side to side. The number of saccadic movements (eye movements) per line is considered optimal at 64 to 84 characters. It may be less for struggling brains.

The Norway study compared reading text on paper to text on 15 inch screens. There was no mention of line length in characters or inches.

Lines on NT are about 85 to 90 characters so they can be a struggle. Many of us on NT promote short paragraphs of 5 or 6 lines max to make reading from one line to the next easier. Otherwise, the visual struggle can be a problem. The longer the line length, the more limiting the number of lines in a paragraph makes a difference.

So, it may help to try different line lengths to see if there is a limit.